SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY • NUMBER 19 Permian Brachiopods of West Texas, III (PART 1-TEXT) G. Arthur Cooper and Richard E. Grant iSi>U£0 DEC 29 SMITHSONIAN INSTITUTION PRESS City of Washington 1975 ABSTRACT Cooper, G. Arthur, and Richard E. Grant. Permian Brachiopods of West Texas, III. Smithsonian Contributions to Paleobiology, number 19 (part 1: text; part 2: plates), pages 795-1921, plates 192-502, 1975.—The third of a six-part mono- graph on the Permian brachiopods of the Glass, Guadalupe and other mountain ranges of West Texas, this volume contains systematic descriptions of genera and species in the suborders Productidina and Chonetidina. The Productidina, which constitute about 45 percent of the brachiopod specimens in the collections from West Texas, are divided into the superfamilies Strophalosiacea, Aulostegacea, Richthofeniacea, and Productacea. The Chonetidina, less numerous, contain the single superfamily Chonetacea. Permian Brachiopods of West Texas, I. Smithsonian Contributions to Paleobiology, number 14, 231 pages, 39 figures, 23 plates. Issued 29 December 1972. Permian Brachiopods of West Texas, II. Smithsonian Contributions to Paleobiology, number 15, pages 233-793, figure 40, plates 24-191. Issued 16 April 1974. Official publication date is handstamped in a limited number of initial copies and is re- corded in the Institution's annual report, Smithsonian Year. SI Press number 4808. Series cover design: The trilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Cooper, Gustav Arthur, .1902- Permian brachiopods of West Texas. (Smithsonian contributions to paleobiology, no. 14-15, 19) Supt. of Docs: SI 1.30: 19 Includes bibliographies. 1. Brachiopods, Fossils. 2. Paleontology—Permian. 3. Paleontology—Texas. I. Grant, Richard E., joint author. II. Title. III. Series: Smithsonian Institution. Smithsonian contributions to paleobiology, no. 14 [etc.] QE701.S56 no. 14, etc. [QE796] 560'.8s [564\8'097649] 72-4218 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 Price domestic postpaid or GPO Bookstore Contents Page Order Strophomenida ..... ........................... 795 Suborder Productidina .......................................... ...... 795 Superfamily Strophalosiacea ............................ ........ 795 Family Strophalosiidae ....................._______........... . 795 Subfamily Strophalosiinae .... ........ ...... ................. .......... 795 Genus Strophalosia ................... ...................... ..... 795 Genus Heteralosia........................................ . ...... 796 Subfamily Ctenalosiinae .......... . . ...... ............... 802 Genus Ctenalosia ... ....... ............ ........... ......... 802 Family Teguliferinidae..................... .... ............. ........... 808 Genus Teguliferina .............................. ....... 809 Genus Acritosia ............................ .............. .. . . 816 Superfamily Aulostegacea............... .................... 822 Family Cooperinidae ............ ......... ...... ........... .... 822 Genus Cooperina ............ ................... . . .. 823 Genus Atelestegastus ........................ ...... ........ 828 Family Aulostegidae ................ ...... ............... ....... 830 Subfamily Echinosteginae ......... ......................... .... 830 Genus Limbella ................................................. 830 Genus Edriosteges ................. .............................. 838 Genus Echinosteges ................... ......... .................. 844 Genus Cactosteges ....................................... .......... 850 Genus Xenosteges .................. ...... ................... 853 Subfamily Chonosteginae.............. .. ................. ....... 861 Genus Chonosteges................................................ 862 Subfamily Institellinae ..................... .................... 871 Genus Institella .......................................... .......... 871 Genus Glyptosteges...................... ...... .............. . . 876 Genus Craspedona ................. ........ .......... ........... 881 Family Spyridiophoridae ...................... ............... .... 883 Genus Spyridiophora ..................... ... .............. ......... .. 884 Family Agelesiidae ................................................... 890 Genus Agelesia ... ...... ............ ...... ................ . 890 Family Scapharinidae ........... ..... 894 Genus Scapharina ........... ........ ............... ........ 895 Family Rhamnariidae ............ .... .......................... 898 Genus Spuriosa ................ .................. ... ............. 898 Genus Ramavectus.................................................... 899 Genus Rhamnaria .................................................. 901 Family Tschernyschewiidae ................. ......................... 914 Genus Tschernyschewia............................................ .. 914 Family Scacchinellidae ..................................................... 917 Genus Scacchinella ..................................... . ...... 917 Superfamily Richthofeniacea ...................... .................. 926 Family Hercosiidae ................................................. 928 Genus Hercosia........................................................ 928 Genus Hercosestria...................................... ........... 935 Family Cyclacanthariidae .......................................... 938 Genus Cyclacantharia ............ .... .......... ...... ........ 939 Genus Taphrosestria........................ .................... 954 Genus Sestropoma ............... ... ...... .......... 958 Genus Collumatus .......................... ........ ........ 961 Family Richthofeniidae ................................................. 962 iii iv SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Page Genus Richthofenia ......... ..... ...... ........................... 962 Subfamily Prorichthofeniinae .......... ...................... 963 Superfamily Productacea ................... ... ............ .. 963 Family Overtoniidae ................................................. 963 Subfamily Overtoniinae ....... . . ..... ....... ........ 963 Genus Fimbrinia ............ ................................ 963 Genus Simplicarina ............................ . . 966 Genus Rhytisia ............................ ........, . . ...... 967 Family Marginiferidae ................ ... ..... ......... 969 Subfamily Marginiferinae ....................... ..... 969 Genus Kozlowskia.................... ...................... ... 969 Genus Hystriculina ...................... . . ..... . . ............. 977 Subfamily Costispiniferinae ....................... ........... .... 984 Genus Bothrionia ............ ...... .... ...................... 984 Genus Costispinifera ....... . . ........ ...... 989 Genus Elliottella ................................................ 994 Genus Echinauris.................................. ............. 1000 Genus Oncosarina..................................... .... 1018 Subfamily Retariinae ............. 1023 Genus Kutorginella................... .... ................ 1023 Genus Thamnosia ........................... . .......... .. 1031 Family Echinoconchidae......................... ................ .... 1038 Subfamily Echinoconchinae......... ....... ............................ ... 1038 Genus Echinaria.......................... .... ....... 1038 Genus Calliprotonia ................. .... ........ .............. . . 1040 Genus Bathymyonia .................................. .... 1040 Subfamily Waagenoconchinae .... ....... ............... .... ..... 1041 Genus Waagenoconcha.................. ....................... 1041 Family Buxtoniidae ................. ......... .... 1049 Subfamily Buxtoniinae................................................ 1049 Genus Kochiproductus .......... ......................... 1049 Genus Ametoria ............................ .......... ...... .... 1055 Subfamily Juresaniinae ................ ... .... 1056 Genus Juresania .............. .... ..... ........................ 1057 Family Dictyoclostidae ................................ ...... ... 1058 Subfamily Dictyoclostinae ....................................... 1058 Genus Spinarella ................. .......................... 1058 Genus Xestosia .... ..... .......... 1063 Genus Nudauris ...... ............ ....... ...... ..... 1066 Genus Dasysaria ................................. ...... . . 1075 Genus Rugatia ............ ................................. .... 1077 Genus Spinifrons . . ........ ........................ 1084 Genus Reticulatia ............. ....... ..... .................. 1086 Genus Antiquatonia ......... ......... ...... .... ........ . . 1090 Genus Peniculauris....................... .......... .... 1093 Subfamily Horridoniinae . . .. ... ................. 1101 Genus Horridonia............................................ \\Q\ Family Paucispiniferidae . . .......... 1102 Genus Anemonaria............................................ 1102 Genus Liosotella . . . . ..... ...... ...................... HO4 Genus Paucispinifera ........ . „................................... H20 Genus Polymorpharia .......................................... 1143 Family Linoproductidae ......... ................... II45 Subfamily Linoproductinae . . II45 Genus Linoproductus ............................................ 114g Genus Cancrinella . ..................................... H50 Genus Liraria ... ... ...... ........................... 115g Genus Undellaria ....... . ................................. _ 1157 Genus Grandaurispina ................................................ II59 Genus Holotricharina ............ ................................... j 173 Genus Yakovlevia ...... ........................ . . ... 1177 Genus Siphonosia ............. Subfamily Anidanthinae ........... Genus Megousia ............... Subfamily Striatiferinae .......... Genus Striatifera .............. Genus Compressoproductus ..... Uncertain and Misidentified Productacea Suborder Chonetidina .............. Superfamily Chonetacea ......... ..... Family Rugosochonetidae ........... Page 1188 ............... ................ 1190 ................... 1190 .............................. 1200 .................................. 1201 ..... ........................... 1202 ............................... 1212 ........................... 1212 ................................ 1212 ................................. 1212 Subfamily Rugosochonetinae ................................ 1213 Genus Sulcataria .................. ...................... 1213 Genus Neochonetes . . ....... ....... ...... ............. .. 1217 Genus Dyoros (Dyoros) ............................. 1220 Genus Dyoros (Lissosia) ...... . .. ............... 1241 Genus Dyoros (Tetragonetes).......... .......................... . . 1246 Genus Lissochonetes ................... ....... ..... ....... . . . 1258 Genus Leurosina............................... ................ 1260 Genus Mesolobus . .......... ............ ........................ 1266 Genus Quadrochonetes ........................................ 1267 Subfamily Lamellosiinae ...... ...... .... ........................ 1270 Genus Lamellosia .................. ........ ......................... 1270 Subfamily Chonetinellinae ....................... 1270 Genus Chonetinella........................................... 1271 Genus Chonetinetes .......................... ....... ........... 1281 Subfamily Undulellinae ................ ......................... 1286 Genus Undulella ...... .......................................... 1286 Genus Micraphelia......................... ..... 1291 Subfamily Plicochonetinae ................. .. ..... 1295 Genus Rugaría......................................... .. 1295 Literature Cited ___ ........................... ....................... 1297 PLATES 192. 193. 194. 195. 196. 197. 198. 199. 200. 201. 202. 203. 204. 205. 206. 207. 208. 209. 210. 211. 212. 213. 214. 215. 216. Heteralosia, Ctenalosia, and Liosotella Heteralosia ....................... Spuriosa and Heteralosia ......... Heteralosia ...................... Heteralosia ........... ....... Ctenalosia............ ....... Ctenalosia ...... ....... Acritosia ....... ...... ....... Acritosia and Richthofenia ...... Acritosia ............. ....... Acritosia ............. ....... Acritosia and Teguliferina ........ Teguliferina................... 1300 1302 1304 1306 1308 1310 1312 1314 1316 1318 1320 1322 1324 Teguliferina .................................................... ...... 1326 Teguliferina....................................................... ...... 1328 Teguliferina ..... .......................... ............... . . 1330 Paucispinifera, Liosotella, Cooperina, Glyptosteges, and Horridonia .............. 1332 Cooperina ............ ................ ...................... 1334 Cooperina ............................ . .............................. 1336 Atelestegastus ................................... . ................. 1338 Chonosteges and Cooperina ..........................f .................... 1340 Limbella ............ .................................................. 1342 Limbella ................................................................ I344 Limbella ................................................................... 1346 Limbella ................................................................. 1348 Vi SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Page 217. Paucispinifera, Cyclacantharia, Limbella, and Rhamnaria .... ....... ....... 1350 218. Edriosteges ............................................................... 1352 219. Edriosteges ............................................. 1354 220. Edriosteges ............................................................... !356 221. Edriosteges .. .......................................................... 1358 222. Edriosteges .............................. ............................ 1360 223. Edriosteges and Echinosteges............................................... 1362 224. Echinosteges..................................................... 1364 225. Echinosteges ..................................................... 1366 226. Echinosteges.......................................................... 1368 227. Echinosteges...................................................... 1370 228. Echinosteges .................. ........ ........ . 1372 229. Echinosteges .......................................................... 1374 230. Echinosteges................................................... 1376 231. Agelesia, Spyridiophora, and Cactosteges ........ ....... .............. 1378 232. Xenosteges .............................................. 1380 233. Hystriculina and Xenosteges............................................... 1382 234. Xenosteges ......................................................... 1384 235. Xenosteges................................................................ 1386 236. Xenosteges .............................................................. 1388 237. Scapharina and Kutorginella .......................... . ................... 1390 238. Scapharina.............................................................. 1392 239. Scapharina ................................................................ 1394 240. Chonosteges .......................................................... 1396 241. Chonosteges ......................................................... 1398 242. Chonosteges ............................................................... 1400 243. Chonosteges ........................................................ 1402 244. Chonosteges, Yakovlevia, Echinosteges, Paucispinifera, Oncosarina, and Xenosteges 1404 245. Chonosteges ......................................................... 1406 246. Institella and Peniculauris .................... ................... 1408 247. Institella................................................................ 1410 248. Institella............................................................... 1412 249. Glyptosteges ......................................................... 1414 250. Glyptosteges ............................................................ 1416 251. Spyridiophora .......................................................... 1418 252. Spyridiophora ........................................................ 1420 253. Spyridiophora and Glyptosteges ........ ............................ 1422 254. Craspedona ........................... ........................ 1424 255. Agelesia .......................................................... 1426 256. Ametoria and Ramavectus ...................... ........................ 1428 257. Limbella and Ramavectus ........................ ....................... 1430 258. Rhamnaria, Ramavectus, and Echinosteges ...................... 1432 259. Rhamnaria ........................................... ................. 1434 260. Rhamnaria ....................................... ................. 1436 261. Rhamnaria ................................... .............. .. 1438 262. Rhamnaria ............................................................... 1440 263. Rhamnaria .......... ............................ ...... 1442 264. Rhamnaria ....................... ............................... I444 265. Rhamnaria ................................................................ 1446 266. Rhamnaria ......................... .... ¡44g 267. Echinosteges and Rhamnaria..................................... ....... I45O 268. Tschernyschewia ....................................... ... ............ 1452 269. Tschernyschewia and Strophalosia ......... ........ 1454 270. Scacchinella ..................................... ................ I456 271. Scacchinella................................................................. 145g 272. Scacchinella .......... ........................ .. ... 14gn 273. Scacchinella ................................... .................. 1402 274. Scacchinella .... ............................ ................. 1464 275. Scacchinella ....... ................. .......................... 1466 276. Scacchinella ................. ............... -----.................. 1468 NUMBER 19 ¦..-, Vil Page 277. Scacchinella ...... ..................................................... 1470 278. Scacchinella ............................................................ 1472 279. Scacchinella ................................................................ 1474 280. Scacchinella , . ......................................................... 1476 281. Scacchinella ................................................. .. 1478 282. Scacchinella ...................................................... 1480 283. Scacchinella .......................................................... 1482 284. Dyoros (Dyoros), Scacchinella, Sestropoma, and Acritosia ........................ 1484 285. Hercosia ................................................................... 1486 286. Hercosia ...................................................................... 1488 287. Hercosia ..................................................................... 1490 288. Hercosia ........................ .......................................... 1492 289. Hercosestria and Hercosia ............. ............. .......... 1494 290. Hercosia and Hercosestria ................... .................... 1496 291. Hercosestria........................... ...................... 1498 292. Hercosestria ............................................................. 1500 293. Hercosestria ................................. ....................... 1502 294. Acritosia and Cyclacantharia ............... ...................... 1504 295. Cyclacantharia ................................ . .................... 1506 296. Cyclacantharia ........................... ................ 1508 297. Cyclacantharia ................................. ........ 1510 298. Cyclacantharia .......................... ....................... 1512 299. Cyclacantharia ........................................ ......... 1514 300. Cyclacantharia .............................................. ...... 1516 301. Hercosia and Cyclacantharia ..................... ....................... 1518 302. Cyclacantharia .......................... ........................... 1520 303. Taphrosestria ..................................................... 1522 304. Taphrosestria ___ ............... ........................... 1524 305. Taphrosestria and Collumatus....... . ....................... 1526 306. Collumatus and Sestropoma........ ............................. 1528 307. Sestropoma.......... ................................ 1530 308. Acritosia, Cyclacantharia, and Sestropoma .................................... 1532 309. Acritosia, Hercosia, Teguliferina, Collumatus and Cyclacantharia ............... 1534 310. Fimbrinia, Simplicarina, Oncosarina, and Costispinifera ..................... ... 1536 311. Fimbrinia and Rhytisia .. ................................. 1538 312. Kozlowskia, Costispinifera, and Simplicarina .............................. 1540 313. Kozlowskia ............................................................ 1542 314. Kozlowskia ................................................. 1544 315. Hystriculina ......... .............................................. 1546 316. Bothrionia and Thamnosia . ................................... 1548 317. Bothrionia ................................... .................... 1550 318. Oncosarina and Bothrionia 1552 319. Costispinifera.......................................................... 1554 320. Costispinifera ....................................................... 1556 321. Costispinifera ................................................... 1558 322. Elliottella............................ ...................... 1560 323. Elliottella ....................................................... 1562 324. Oncosarina .................................. ...... ............ 1564 325. Hystriculina and Elliottella ................... . 1566 326. Echinauris ............................................................ 1568 327. Echinauris ................................ . 1570 328. Echinauris .................................. ..................... 1572 329. Echinauris . . ................. .... ..................... 1574 330. Echinauris . . . . ................. ___ 1576 331. Echinauris........... ........... ..... ........ 1578 332. Echinauris . ......... .................. 1580 333. Echinauris ....... ... 1582 334. Echinauris ............. ........ .................. .. 1584 335. Echinauris...................... ...............------ 1586 336. Echinauris ................................... .......................... 1588 vm SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOG Page 337. Echinauris ........................,...... .............................. 1590 338. Echinauris ........ ................................................... 1592 339. Echinauris.............................................................. 1594 340. Echinauris ...... .................... .............................. 1596 341. Echinauris . . ........... ..........., ................................... 1598 342. Kutorginella ..................................................... 1600 343. Kutorginella ............................. .................. ......... 1602- 344. Kutorginella ...........................____ .......................... 1604 345. Thamnosia ..................... ...... ...... .......................... 1606 346. Thamnosia ..................... ..................................... 1608 347. Thamnosia .......................................................... 1610 348. Thamnosia ..................................... ......................... 1612 349. Thamnosia ............................ ..... ............. ...... 1614 350. Kutorginella ............................................................ 1616 351. Thamnosia and Rhamnaria ................................................ 1618 352. Bathymyonia and Waagenoconcha....................................... 1620 353. Hercosia, Juresania, and Bathymyonia............. ............................ 1622 354. Waagenoconcha ...................... ............................. 1624 355. Waagenoconcha ................... ................................. . 1626 356. Waagenoconcha ......................... ................................. 1628 357. Waagenoconcha .......................................................... 1630 358. Kochiproductus.........................................................:. 1632 359. Kochiproductus........................................................... 1634 360. Kochiproductus .......................................................... 1636 361. Kochiproductus ............................................................ 1638 362. Rhamnaria and Kochiproductus ......................................... 1640 363. Dasysaria ................................................................... 1642 364.. Dasysaria ................................................................. 1644 365. Dasysaria and Nudauris .................................. ............. 1646 366. Xestosia and Nudauris................................................... 1648 367. Echinauris, Xestosia, and Nudauris ................................ . ........ 1650 368. Nudauris ..........................................................___ 1652 369. Nudauris ..........i..................................................... 1654 370. Nudauris .................................................................... 1656 371. Nudauris and Xestosia ..................................................... 1658 372. Nudauris................................................................ 1660 373. Rugatia ................................................................... 1662 374. Rugatia . . ............................................................ 1664 375. Rugatia ...... .. ...................................................... 1666 376. Rugatia ................................................................ ... 1668 377. Rugatia ............................................................... .... 1570 378. Rugatia and Reticulatia................................................ 1672 379. Spinarella .............................................................. 1674 380. Spinarella ... ........................................................ 1676 381. Spinarella .............................................................. 1678 382. Xestosia ................................................................. 1680 383. Xestosia and Reticulatia............................................. 1682 384. Spinifrons ................................................................. 1684 385. Spinifrons ............................................................. 1686 386. Reticulatia, Antiquatonia, Calliprotonia, and Echinaria .................... 1688 387. Spinifrons ............................................................... I690 388. Spinifrons ................................................................ jg92 389. Spinifrons ............................................................ . .. 1694 390. Spinifrons and Antiquatonia.......................................... ... 1696 391. Antiquatonia............................................................. 1698 392. Reticulatia.................................................................... I7OO 393. Reticulatia ...................................................................¦. 17Ó2 394. Peniculauris............................................................... 1704 395. Peniculauris .............................................................\. 1706 396. Peniculauris............................................................. 1708 NUMBER 19 IX Page 397. Peniculauris .............. ..... ..................... 1710 398. Peniculauris ..................................................... 1712 399. Peniculauris ............................. ................... 1714 400. Peniculauris .......................... ........................... 1716 401. Peniculauris ....................................................... 1718 402. Peniculauris ............................. .. ....... ...... 1720 403. Peniculauris ............................................................... 1722 404. Peniculauris ................................................................. 1724 405. Peniculauris ............................................................... 1726 406. Peniculauris .................................................................. 1728 407. Peniculauris................................................................. 1730 408. Anemonaria ................................................................... 1732 409. Liosotella ............................................................... 1734 410. Nudauris, Echinauris and Liosotella ........................................... 1736 411. Liosotella................................................................... 1738 412. Liosotella and Grandaurispina ................................................. 1740 413. Liosotella ........,....................................................... 1742 414. Liosotella .................................................................... 1744 415. Liosotella ................................................................... 1746 416. Liosotella ......... .......................... ....................... 1748 417. Paucispinifera ....................................................... 1750 418. Paucispinifera ............................................................ 1752 419. Paucispinifera and Oncosarina ............................................ 1754 420. Paucispinifera ............................................................ 1756 421. Paucispinifera............................ ................. 1758 422. Paucispinifera.......................... ..................... 1760 423. Paucispinifera .............................. ...................... 1762 424. Paucispinifera ...... .................... .................... 1764 425. Paucispinifera ................................ .......................... 1766 426. Paucispinifera .......................... ...... ..... 1768 427. Polymorpharia ............................. ........ 1770 428. Cancrinella . . .......................... ................... 1772 429. Cancrinella .................................... ........ ___ 1774 430. Cancrinella and Grandaurispina ......... ............................ ..... 1776 431. Linoproductus ......................................................... 1778 432. Linoproductus ........................... .......................... ... 1780 433. Compressoproductus and Linoproductus ................................... 1782 434. Yakovlevia and Liraria ................................................ ..... 1784 435. Grandaurispina ............................................................... 1786 436. Grandaurispina ....................................................... 1788 437.. Grandaurispina 1790 438. Grandaurispina ............................. ............................ 1792 439. Grandaurispina ............................. ............................ 1794 440. Grandaurispina ............................................................. 1796 441. Grandaurispina ..................................................... 1798 442. Grandaurispina ......................... .................... 1800 443. Grandaurispina ......................................................... 1802 444. Holotricharina ............................................................ 1804 445. Echinaria, Holotricharina, Hystriculina and Calliprotonia .................... 1806 446. Acanthocrania, Paucispinifera, Elliottella, Liosotella, Megousia, and Holotricharina 1808 447. Megousia and Kozlowskia ............................................... 1810 448. Megousia ......................................................... 1812 449. Megousia ............................................................... 1814 450. Megousia ........... .......................................... 1816 451. Megousia ... ...................... 1818 4'52. Megousia and Yakovlevia .......... .... ..................... 1820 453. Megousia, Grandaurispina, Linoproductus, Antiquatonia, and Kozlowskia ........ 1822 454. Compressoproductus..................... . ................... . 1824 455. Striatifera and Compressoproductus ........ ....................... 1826 456. Compressoproductus ........................ ....................... 1828 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Page 457. Compressoproductus ...................................................... 1830 458. Compressoproductus .................................................... 1832 459. Compressoproductus ............... ...... ............................ 1834 460. Compressoproductus ................................................... 1836 461. Compressoproductus ............................................... , ... 1838 462. Compressoproductus and Striatifera................................... 1840 463. Institella, Megousia, Compressoproductus, and Striatifera ............. ......... 1842 464. Compressoproductus and Polymorpharia.................................. 1844 465. Striatifera ............................................................ 1846 466. Siphonosia .......................................................... 1848 467. Siphonosia, Megousia, and Undellaria ................................. 1850 468. Horridonia, Echinauris, Institella, Glyptosteges, Siphonosia, and Nudauris ..... 1852 469. Yakovlevia ........................................................... 1854 470. Yakovlevia .............................................................. 1856 471. Yakovlevia ...................................................... 1858 472. Yakovlevia ............................................................... 1860 473. Yakovlevia.......................................................... 1862 474. Yakovlevia .......................................................... 1864 475. Spyridiophora, Paucispinifera, Limbella, Striatifera, and Orthotichia ...... 1866 476. Echinauris, Sestropoma, Paucispinifera, and Rugoclostus .................... 1868 477. Chonetinetes .................................................. ;..... 1870 478. Chonetinetes, Chonetinella, and Sulcataria .................................... 1872 479. Chonetinella and Leurosina ............. ................................. 1874 480. Chonetinella and Sulcataria ................................................ ] 876 '481. Dyoros (Dyoros) ........................... .............................. 1878 482. Dyoros (Dyoros) ........................ ...... 1880 483. Dyoros (Dyoros)............................ ............................ 1882 484. Dyoros (Dyoros)............................. ....................... 1884 485. Dyoros (Dyoros) ............................. ..................... .... 1886 486. Dyoros (Dyoros) .................................................. ,......... 1888 487. Dyoros (Dyoros) and Dyoros (Lissosia) ...................................... 1890 488. Dyoros (Lissosia).............................................. ...... 1892 489. Dyoros (Lissosia) and Dyoros (Tetragonetes)........ ................ .... .. 1894 490. Dyoros (Tetragonetes) .................................................. 1896 491. Dyoros (Tetragonetes), Lissochonetes, and Quadrochonetes .......... .... 1898 492. Dyoros (Tetragonetes) and Undulella .............................. ...... 1900 493. Micraphelia ............................................................... 1902 494. Leurosina .................................................................. 1904 495. Leurosina and Dyoros (Tetragonetes) ......................................... 1906 496. Mesolobus?, Rugaría, and Neochonetes ................................. 1908 497. Neochonetes, Dyoros (Tetragonetes), and Lamellosia ...................... .... 1910 498 Rugaría, Leurosina, Dyoros (Tetragonetes), Dyoros (Dyoros) and "Chonetes" ,...... 1912 499. Dyoros (Tetragonetes) and Rugaría....................................... 1914 500. Chonetinella, Dyoros (Dyoros), and Leurosina........................ 1916 501. Dyoros (Dyoros), Chonetinella, and Micraphelia .................................. 1918 502. Quadrochonetes, Undulella, Dyoros (Lissosia), Dyoros (Dyoros), and Chonetinetes . . 1920 Permian Brachiopods of West Texas, III G. Arthur Cooper and Richard E. Grant Order STROPHOMENIDA Öpik, 1934 Suborder PRODUCTIDINA Waagen, 1883 Superfamily STROPHALOSIACEA Schuchert, 1913 Family STROPHALOSIIDAE Schuchert, 1913 Primitive Strophalosiacea with hinge teeth in the pedicle valve and sockets in the brachial valve. Pedicle valve having an interarea; delthyrium closed by a flat or convex pseudodeltidium. Noto- thyrium, if present, covered by a chilidium. Pedicle valve anchored by rhizoid spines and umbonal ce- mentation. Cardinal process initially bilobed but becoming trilobed to bulbous with age. Subfamily STROPHALOSIINAE Schuchert, 1913 Strophalosiidae having a smooth dorsal valve, without spines. Genera in West Texas: Strophalosia W. King (1844) is extremely rare in West Texas, only four specimens having been found; Heteralosia is a genus common in West Texas in the Permian and Pennsylvanian. Muir-Wood and Cooper (1960) erroneously de- scribed the subfamily Strophalosiinae as having a spiny dorsal valve. They then created the Hetera- G. Arthur Cooper and Richard E. Grant, Department of Paleobiology, National Museum of Natural History, Smith- sonian Institution, Washington, D.C. 20560. losiinae for genera of strophalosiids having a dorsal valve without spines. Brunton (1966) studied the type specimens of Strophalosia gerardi W. King, type-species of the genus, and was unable to find any trace of spines on its dorsal valve. He therefore recommended the elimination of the Heteralosiinae. Heteralosia proves to be different generically from Strophalosia but belongs in the same family. Genus Strophalosia W. King, 1844 Strophalosia inexpectans, new species Plate 269: figures 13-30 Medium size, but large for genus, wider than long, subquadrate in outline; concavo-convex; sides mod- erately rounded, greatest width at midvalve; hinge narrower than midwidth, straight, with short in- terarea. Anterior margin rounded to somewhat truncated medially. Rhizoid spines short and deli- cate, concentrated on ears, umbonal, and postero- lateral slopes; ornament spines numerous, delicate, recumbent, covering entire surface. Pedicle valve fairly evenly and moderately con- vex in lateral profile; anterior profile broadly con- vex, moderately steep lateral slopes. Umbonal region swollen moderately but extended slightly posterior to posterior margin. Median region greatly swollen, long anterior slope moderately swollen but not steep. Interarea orthocline. Del- thyrium small and narrow and covered by a slightly convex pseudodeltidium. Ears poorly developed, obtuse. Cicatrix of attachment small. 795 796 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Brachial valve not well known, moderately concave; deepest posteromedially; posterolateral regions flattened; interarea short, hypercline. Or- nament spines thin and delicate. Pedicle valve interior with small, delicate teeth very closely spaced. Adductor scars large and rounded; diductor scars flabellate and surrounding adductors. Brachial valve interior with long narrow cardinal process extending nearly perpendicular to posterior margin. Sockets deep. Adductor scars elongate; me- dian ridge low, rounded, extending to base of car- dinal process and to about midvalve in anterior direction. Measurements (in mm).— brach- ial sur- valve face mid- hinge length length length width width height AMNH 512 151229a 26.9 23.0 33.0 30.0 20.0 10.6 151229b 23.6 20.5 28.0 30.4 22.0 9.5 (holotype) 151229c 23.4 19.4 27.0 27.3 20.8 8.0 Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Member). Locality.—AMNH 512 (= USNM 728). Diagnosis.—Large Strophalosia with numerous fine recumbent hairlike spines on the brachial valve and short rhizoid spines on the ears. Types.—Holotype: USNM 151229b. Figured paratypes: USNM 151229a, c, d. Measured para- types: USNM 151229a, c. Comparison.—No other strophalosiid of this type is now known from North American Permian rocks. The genus Strophalosia, sensu stricto, ap- pears hitherto to have been restricted to the Perm- ian of Asia and Australia. Some species have been described from the latter place and the type of the genus is from the Himalayas but it is poorly known. Species from Australia usually assigned to Stropha- losia have a spinose brachial valve, a feature shared with S. inexpectans. Strophalosia inexpectans cannot be compared favorably with any of the Australian species which are much larger and more robust, usually with stronger spines and with details of the interior different from those of the Guadalupe Mountains species. The Australian strophalosias usually have the cardinal process thick-shafted but the median ridge is not strongly developed. A platform for the ventral adductor muscles is usually present in these austral species. S. gerardi W. King, the type spe- cies of the genus, is also a large form very similar to the Australian species but its interior is un- known. The American species is wider-hinged than any of the species figured by Coleman (1957). Discussion.—This species is known from only four specimens, three pedicle valves and one frag- mentary brachial valve. Considering the enormous quantity of material from AMNH 512 = USNM 728 dissolved by the two institutions, this proves to be one of the rarest species in the Guadalupe Moun- tains. It is of special interest as the first represen- tative of the genus to be found on this continent. Genus Heteralosia R. H. King, 1938 Heteralosia hystricula (Girty) Plate 193: figures 45, 46; Plate 194: figures 16-31; Plate 195: figures 1-43 Strophalosia hystricula Girty, 1909:275, pi. 30: figs. 14, 14a. [Not of R. E. King, 1931:96.] Small, subcircular in outline, lateral and anterior margins rounded; hinge narrower than greatest width at midlength. Commissure without fold; pedicle valve adorned by rhizoid and ornament spines, rhizoid spines in row along hinge, numerous on ears, and scattered distantly over entire sur- face. Ornament spines stout and recumbent, usu- ally short, many lying closely and irregularly along valve surface, those on valve edge usually longer and attaining length about 7 mm. Brachial valve marked by small dimples and mounds. Pedicle valve strongly and evenly convex in lateral profile, broadly domed in anterior profile; cicatrix of attachment large, usually occupying en- tire umbonal region. Median region strongly inflated; lateral and anterior slopes steep; ears minute, poorly defined; interarea short, broadly tri- angular, flat, covered by slightly elevated pseudo- deltidium. Teeth small, long, about 1 mm. or less apart. Adductor field small, elevated to form sub- triangular callosity with central longitudinal ridge or carina; adductor callosity in old individuals par- tially excavate. Diductor scars large, surrounding adductor field and occupying about posterior half of valve. NUMBER 19 797 Brachial valve irregular but generally moderately concave, umbonal region slightly convex. Anterior margin somewhat abruptly reflected dorsally. In- terior with laterally compressed cardinal process, lobes of myophore separated only by narrow groove in anteroventral face in young, but varying with age to bilobed and trilobed. Sockets deep, floored by small horizontal plates and roofed by extensions of palintrope. Adductor field subcircular, small, divided by thin but low median septum extending slightly anterior to midvalve. Measurements (in mm).— brach- ial maxi- valve hinge mum thick- length length width width height ness USGS 3763 118545 10.0 ? 8.3 11.7 4.7 ? (holotype) USNM 706e 152629a 12.9 ? 12.3 15.9 5.5 ? 152629b 11.4 ? 10.6 13.3 5.1 ? 152629c 11.0 7.9 6.8 11.7 3.4 ? 152629e ? 8.0 11.0 11.0 ? ? USNM 706b 152630a 10.4 9.0 8.5 12.1 4.6 2.6 152630b 10.9 8.4 8.6 12.9 4.6 2.7 152630c 8.4 6.8 7.3 10.5 4.2 2.2 152630d 7.4 5.7 5.2 7.8 3.0 1.6 152630e 11.0 9.8 8.2 13.3 5.0 4.3 152630g 11.9 ? 10.7 14.6 6.7 ? Stratigraphic Occurrence.—Road Canyon For- mation, Word Formation (China Tank, Willis Ranch, Appel Ranch members and lenses between the last two), Cherry Canyon Formation. Localities.—Road Canyon: USNM 703c, 716xa, 721j, 721z, 723w, 724c. Word: USGS 3763; USNM 732s. China Tank: USNM 703e, 706a, 706c, 706z, 713, 726r, 733q. Willis Ranch: AMNH 505, 506; USNM 706, 706e, 723t, 724u, 735c. Appel Ranch: 704, 706d, 714o, 715i, 719z, 726t. Lenses: 706b, 732c. Cherry Canyon: USNM 728. Types.—Holotype: USNM 118545. Figured hy- potypes: USNM 123891g; 153581b; 154115a-l; 154116a-f; 154117a, c; 154118a-e. Measured hypo- types: USNM 152629a-c, e; 152630a-e, g. Diagnosis.—Subcircular, moderately large Het- eralosia with numerous stout rhizoid spines. Comparison.—No foreign or North American species is like H. hystricula (Girty). The Salt Range species described by Reed (1944) are mostly much larger and not comparable. In North America H. mexicana Cooper, which comes from beds of about the same age as the Glass Mountains species, is larger and is less convex and somewhat subquad- rate rather than circular. Discussion.—The spines, muscle area of the ped- icle valve, and the cardinal process are anatomi- cal features of H. hystricula that need elaboration. In most specimens the rhizoid or attachment spines are confined to the cardinal extremities and the posterior margin. As in other attached forms the young stages of this species are fixed to their anchorage by a fringe of rhizoid spines around the margin of the cicatrix. These spines are sufficient to fix the young forms, but the larger specimens need additional anchorage. This is accomplished by rhizoid spines given off at almost any point on the anterior slope of the pedicle valve. These spines are scattered among the prostrate ornament spines. They are given off at about right angles to the shell surface and are extended toward the substratum and grow until contact is made. They are extended along the surface of the object of attachment for a distance sufficient to accomplish their purpose. The rhizoid and ornament spines can be distin- guished readily on exfoliated shells. The orna- ment spines are given off from the shell surface obliquely but early turn at an angle to grow al- most parallel to the surface. Shells found loose on the outcrop or broken from rock have many of the spines stripped off. Most of the rhizoid spines are destroyed but the ornament spines are only par- tially stripped away because they so closely follow the surface slope. The bases of the stripped oft rhizoid spines show as small circular holes but the bases of the ornament spines usually consist of the angularly bent proximal end. The part of the muscle area of the pedicle valve of interest is that concerned with the adductor mus- cles. In young specimens the adductor scars appear on each side of a low, linear, scarcely perceptible, median ridge located just under the delthyrium and extending anteriorly for about one-quarter valve length. With advancing age and size this mus- cle region is gradually thickened, but the increase in thickness is uneven. Most of the thickening takes place medially and emphasizes the height of the median myophragm. The area in question be- comes triangular in outline, the base of the tri- angle being the truncated anterior margin of the adductor field. With advancing age the anterior of 798 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY this triangular callosity is excavated to form a some- what tentlike plate. The excavation is seldom deep into the callosity, but, nevertheless, may be con- spicuous. Inside the brachial valve the cardinal process goes through interesting changes with growth. Normally the shaft of the cardinal process of the adult is short, with the myophore extending obliquely pos- teriorly at a low angle to the commissure. The myo- phore is laterally compressed and narrow, usually with a narrow median depression that divides it into two lobes. On the anteroventral face the car- dinal process also displays a fine median depres- sion, in many specimens widening slightly to indent the distal end of the myophore and emphasize its bilobed character. On the myophore a roughened area (muscle scar) appears on each side of the median depressed line. This is slightly elevated above the margins. In old specimens the median roughened area is expanded and is set off from the lateral depressed areas by deep grooves. This ar- rangement produces a trilobed cardinal process, the median roughened area bounded by depressed lateral lobes. In a few specimens, however, the median roughened lobe is divided by a deep de- pression and it becomes bilobed. This, with the lateral lobes, produces a quadrilobed cardinal process. The shaft of the cardinal process usually is slightly thickened at the base where the sockets are located. With age, strong horizontal ridges may appear at the base of the cardinal process, just an- terior to and bounding the sockets. In other old specimens a ridge or thickening may be developed on the anterior margins of the adductor field to form a chevron-shaped ridge with its apex an- chored in the median septum dividing the adduc- tor scars. Growth.—As usual in attached shells of this type the cicatrix of attachment is fairly large, at- taining 6 mm. in some specimens. Consequently, the young shell is flat and spread out before it geniculates and starts to grow with the anterior part nearly vertical. The adult shell is strongly erect on its attachment surface. The plane of commis- sure is nearly that of a right angle and inclination from the vertical may take place to produce either an acute or an obtuse angle. Variation.—Like all brachiopods that are fixed by part of their shell, H. hystricula is affected in form, size, and ornament depending on the condi- tions under which it grew. Specimens obviously adult or in old age status are dwarfed because of growth against an impeding object. The hinge is a variable part of this species because of impingement against objects or because of distortion by grow- ing on uneven surfaces. In spite of all these diffi- culties the species generally maintains,, its strong convexity and the characteristic spinosity. Ecology.—Heteralosia hystricula apparently at- tached to any solid object with which the larvae came in contact. It is found on nearly all of the common Word brachiopods, small or large, on some of the pelecypods, and on corals and bryozoans. Paucispinifera, probably because it is very abun- dant, is commonly encrusted by H. hystricula. Remarks on Stratigraphy.—The type-specimen of Heteralosia hystricula was collected by R. T. Hill and is said to come from the "Deleware Moun- tain Formation, Comanche Canyon, Glass Moun- tains, Texas (station 3763)." The specimen has the appearance of a Word fossil and is believed to have come from the Word Formation, probably Word (Third Limestone Member of P. B. King = Willis Ranch Member). We have assigned specimens from some localities in the Road Canyon Formation to this species. These have about the same convexity and general form, and the body spines in length and thickness are like those of H. hystricula. Much larger collec- tions are needed before a distinction between these specimens and Girty's species could be established. Heteralosia, however, has proved to be rare out- side of the China Tank and Willis Ranch members. Heteralosia magnispina, new species Plate 192: figures 11-19; Plate 193: figures 12, 13; Plate 196: figures 43-67 Moderate size, subcircular to subquadrate out- line, hinge narrower than greatest width (at mid- valve); sides and anterior margins rounded. Cicatrix variable. Pedicle valve with large, thick rhizoid spines; ornament spines prostrate but stout and distant. Pedicle valve strongly convex in lateral and an- terior profiles; median region strongly inflated; lat- eral and anterior slopes steep; interarea flat, short; teeth small, elongate, closely spaced. Adductor ridge moderately long but not strongly elevated. NUMBER 19 799 Brachial valve with posterior half corresponding to cicatrix, flat to gently convex; anterior half, concave; surface irregularly and coarsely dimpled or irregularly folded. Cardinal process small and delicate; myophore variable but not greatly thick- ened. Shaft stout at base and buttressed by slender lateral plates anterior to sockets. Median septum thick at junction with cardinal process, becoming a slender and delicate partition anteriorly and ex- tending to just beyond midvalve. Adductors with prominent V-shaped ridge on anterior side in adults. Surface, especially in anterior third, marked by fine endospines. Measurements (in mm).— brach- ial maxi- valve hinge mum thick- length length width width ness height USNM 728 151272a 7.3 ? 5.6 7.3 ? 3.5 151272b 7.9 ? 6.8 8.0 ? 4.0? 151272c 7.4 5.9 7.5 8.5 2.8 3.9 151272d 8.0 ? 6.1 8.5 ? 3.1 151272e 8.5 ? 10.0 10.4 ? 3.8 (holotype) 151272f ? 6.4 6.7 7.5 ? ? 151272g ? 7.4 9.0 9.6 ? ? 151272h ? 6.2 6.8 7.5 ? ? Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Member), Bell Canyon For- mation (Hegler, Pinery, Rader, McCombs and Lamar members). Localities.—Getaway: AMNH 21, 512, 519, 600; USNM 728, 730, 732. Hegler: AMNH 635; USNM 731, 732a. Pinery: AMNH 375, 528; USNM 725h, 725n, 733. Rader: AMNH 404, 410; USNM 725f, 725g, 740a, 740i. McCombs: AMNH 385. Lamar: AMNH L-6, 37, 430; USNM 725a, 728i, 728p, 738, 738b. Unplaced: AMNH 524. Diagnosis.—Strongly convex Heteralosia with strong rhiziod spines and distant, coarse ornament spines. Cardinalia delicate. Types.—Holotype: USNM 151272e. Figured paratypes: USNM 151272c, d, f-1, 0; 151289a, b; 154119. Measured paratypes: USNM 151272a-d, f-h. Unfigured paratypes: USNM 151272a, b, d; 151289c. " Comparison.—This species somewhat suggests H. hystricula (Girty) but differs in having fewer and stronger spines of both types on the pedicle valve and generally more delicate structures in the brachial valve. The cardinal process is shorter than that of the Glass Mountains species but the sep- tum is continuous and more prominent in the Guadalupe Mountains species. Discussion.—The collection on which this de- scription is based is mainly from the Getaway Mem- ber (AMNH 512 = USNM 728) which contains ade- quate series. Specimens from other localities are few. Several specimens have finer spines than the majority but even these spines are coarser and less numerous than those of H. hystricula. Specimens from the Bell Canyon Formation usually consist of a few each from many localities and variation among them is considerable. Nevertheless, when they are compared with the standard set from the Getaway Member, we are unable to find any con- sistent differences. The body or ornament spines are of the same size and abundance but the pro- files and shapes are extremely variable. This, however, is characteristic of cemented forms. Sev- eral specimens (lot USNM 151289) of brachial valves have a bizarre development of the so called brachial ridges in which they are elevated anteriorly from the valve floor and simulate those of Xe- nosteges. The ecology of this species seems to be identical to that of H. hystricula but it may have lived in more strongly moving water, accounting for the large and thick anchor spines and the fair abun- dance of specimens stripped off their moorings. Heteralosia paucispinosa, new species Plate 193: figures 26, 27; Plate 196: figures 1-42 Small, subiircular outline, hinge narrower than maximum width; anterior well rounded; cardinal extremities obtuse; cicatrix moderately large; in- terarea moderately long; rhizoid spines stout, in ring around cicatrix; ornament spines few, long and stout, attaining length of 5 mm on anterior margin. Spines borne on poorly defined costae. Teeth small; delthyrium narrow, not covered; median range varying from absent to a thin sep- tum; muscle scars not seen. Brachial valve with anterior half wrinkled and pitted, moderately concave; interarea short, steeply inclined. Interior with narrow, strongly ele- vated cardinal process, not strongly lobate; median ridge low; adductor field slightly thickened. 800 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brach- ial maxi- valve mum hinge length length width width height USNM 731 154129c 10.6 8.7 9.4 6.6 3.5 (holotype) 154129b ? 9.5 11.2 8.6 4.0 154129e 8.8 8.0 8.8 6.3 4.2 Stratigraphic Occurrence.—Bell Canyon For- mation (Hegler, Pinery, Rader and Lamar mem- bers). Localities.—Pinery: AMNH 401. Hegler: USNM 731, 732a, 740c, 740d. Rader: USNM 740a, 740j. Lamar: AMNH 38. Diagnosis.—Small Heteralosia with a few very strong and long spines. Types.—Holotype: USNM 154129c. Figured paratypes: USNM 151280a-c; 154129a, b, d-g; 154130; 154131a, b; 154132a, b; 154133; 155030. Comparison.—This species differs from all the others described herein by its few strong spines and circular outline. Discussion.—As with all Heteralosia this species is very variable, but its strong spines and con- siderable depth help to identify it. Specimens from AMNH 38 show an unusually deep and thick pedicle valve with a moderately thickened diduc- tor region. In the brachial valve the so-called brachial ridges are elevated anteriorly like those of Xenosteges. Specimens larger than usual in the Hegler Member were taken in the Rader Member, USNM 740a. Heteralosia tenuispina, new species Plate 193: figures 15-25 About medium size for genus, narrowly elliptical in outline, length slightly greater than width; hinge narrower than midwidth; anterior broadly rounded; anterior and lateral profiles moderately convex; interarea short and wide; delthyrium narrow, thin pseudodeltidium in holotype. Cicatrix small. Sur- face marked by numerous, short, slender spines; stouter and longer spines along posterior margin. Brachial valve varying from nearly smooth to pitted. Pedicle valve interior with large teeth; muscle area only slightly thickened. Brachial valve interior with small cardinal process and low slender median septum. Measurements (in mm).—From locality USNM 731 specimens 152634b (holotype) and d, respec- tively: length 10.6, (?); brachial valve length 10.0, 7.6; width 13.0, 9.0; hinge width 11.0, 9.5; height 3.6, (?). Stratigraphic Occurrence.—Bell Canyon For- mation (Hegler Member). Locality.—USNM 731. Diagnosis.—Medium-sized Heteralosia with nu- merous fine spines on the exterior of the pedicle valve. Types.—Holotype: USNM 152634b. Figured paratypes: USNM 152634a, c, d. Comparison.—This differs from the other species herein described by its finely spinose exterior. It is a rare species only known from one locality. Heteralosia vidriensis, new species Plate 192: figures 1-10; Plate 193: figures 28-44 About medium size for genus, transversely quad- rangular in outline, width greater than length; cardinal extremities nearly rectangular, slightly ob- tuse or slightly acute; sides gently rounded; anterior broadly rounded. Attachment surface usually small, interarea short, wide; rhizoid spines slightly more than 2 mm long and slender, tapering, scattered openly on surface. Ornament spines concentrated on ears, slender, and also scattered over whole surface. Pedicle valve moderately convex in lateral pro- file, maximum convexity at about midvalve. An- terior profile broadly domed with fairly short slopes moderately steep. Median region generally fairly strongly swollen, swelling extending to anterior in some specimens. Brachial valve moderately convex, fairly well- fitting concavity of pedicle valve; hinge wide, ex- tremities slightly concave. Anterior and sides mod- erately deflected in dorsad direction. Surface closely and fairly deeply pitted to match spines of opposite valve. Pedicle valve interior with small narrow delthy- rium covered by narrowly arched pseudodeltidium; teeth small with flat dorsad surface; adductor plat- form short but strongly developed in adults. Brachial valve with short, low cardinal process with median depression on shaft; median ridge con- NUMBER 19 801 tinuous and reaching anterior to midvalve; sockets small. Measurements, (in mm).— brach- ial valve hinge length length width width height USNM 721u 152632a 8.2 ? 10.7 9.6 3.9 152632b ? 6.6 11.6 10.0 ? 152632c 9.6 ? 12.0 11.6 3.9 152632d 10.4 ? 13.8 10.0 5.1 152632e 9.6 ? 14.0 12.9 3.1 152632g 9.4 ? 12.2 11.7 3.7 (holotype) Stratigraphic Occurrence.—Cathedral Moun- tain Formation, Road Canyon Formation. Localities.—Cathedral Mountain: USNM 72lu. Road Canyon: USNM 722e. Diagnosis.—Medium-sized Heteralosia with transversely rectangular outline and short, slender ornament spines. Types.—Holotype: USNM 152632g. Figured paratypes: USNM 152632a, c, d, f, h. Measured paratypes: USNM 152632a-d, e. Unfigured para- types: USNM 152632e. Comparison.—The transversely rectangular out- line and moderate convexity of the pedicle valve distinguish this species from H. hystricula (Girty). The same features may be used to distinguish it from H. magnispina, new species, but, in addi- tion, the short, slender spines make separation of the two easy. Discussion.—This is a rare species and only 17 specimens were taken. Brachial valves are rare, con- sequently the variation of the brachial structures cannot be detailed. An interesting feature of this species is the scattered ornament spines over the body of the shell. This may be a consequence of its low convexity and the fact that the cicatrix is small. Variation of the pedicle valves is shown by rounding of the cardinal extremities, narrowing of some of the specimens, and differences in depth. Heteralosia species 1 Plate 193: figures 1, 2 A possible new species is represented by a single specimen which is nearly circular in outline, deeply concave dorsally, and has a correspondingly strongly convex pedicle valve. The hinge is much narrower than the maximum width which is at midvalve. The surface of the pedicle valve is provided with numerous fine, prostrate spines, and the brachial valve is nearly smooth, not dimpled as is common in the genus. Measurements in mm are: length 11.3, brachial valve length 8.7, hinge width 5.9, greatest width 12.0, thickness 3.5, and height 6.4. Stratigrachic Occurrence.—Cathedral Moun- tain Formation. Locality.—USNM 702. Type.—Figured and described specimen 152631. Comparsion.—This specimen resembles H. hy- stricula (Girty) but some differences are apparent when the measurements of the latter are com- pared. The Cathedral Mountain specimen is deeper and more convex than the common Word speci- mens. Furthermore, the prostrate spines of Hete- ralosia species 1 appear to be finer and more nu- merous than those of H. hystricula. These differ- ences indicate a species quite different from H. hystricula. Inasmuch as a single specimen is all that is known, the species has not been named. Heteralosia species 2 Plate 193: figure 14 The only specimen representing this species may be a young one or it may represent a flat and thin- bodied form such as H. mexicana Cooper. The specimen measures 5.7 mm in length by 7.1 mm in width and is about one mm thick. The cicatrix is small, suggesting that the specimen may be an adult flat species. Spines on the pedicle valve are few and distantly scattered. Stratigraphic Occurrence.—Road Canyon For- mation. Locality.—USNM 707e. Type.—Figured and described specimen USNM 154120. Discussion.—No other species except the Mexican one referred to above is like this Road Canyon specimen. Heteralosia species 3 This is the largest Heteralosia so far found in the Permian of West Texas. It is 17 mm long by 18 mm wide. It is strongly convex in both profiles and 802 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY it has short, slender, body spines but its ornament spines are thick and stout and concentrated on the ears and sides as well as scattered over the body. The single pedicle valve is from Road Canyon For- mation at USNM 721y. Described specimen USNM 152633. Heteralosia species 4 Plate 193: figure 9 This is a small species with a strongly bulbous pedicle valve which is 9 mm. long by 11 mm. wide. The lateral and anterior slopes are very steep, the spines slender, strongly oblique but not prone and well-scattered. Bone Spring Formation: AMNH 628. Described specimen USNM 151293a. Heteralosia species 5 A coarse-spined species with length and width nearly equal occurs at USNM 721u, Cathedral Mountain Formation. Described specimen USNM 152635. Heteralosia species 6 Plate 193: figure 10 A moderately fine-spined species reminiscent of H. hystricula but not so convex and with some- what fewer spines. Bell Canyon Formation, Rader Member. AMNH 410. Figured specimen USNM 152636. Heteralosia species 7 Plate 193: figures 3-8, 11 About medium size for genus, transversely rec- tangular in outline, sides gently rounded, subtrun- cated anterior margin producing narrowly rounded anterolateral extremities. Interarea very short. Sur- face with short, moderately fine, prone, ornament spines; halteroid spines stout, few, scattered. Pedicle valve gently convex in anterior and lat- eral profile; median region with slight sulcus. Teeth small; muscle region not thickened but with incipient platform. Brachial valve flatly concave; cardinal process short, narrowly pointed. Median septum low, continuous. Measurements (in mm).—From locality USNM 728f, specimens 151274a and 151270, respectively: length 8.3, 7.6; brachial valves unmeasurable; width 11.0, 9.8; hinge width 10.6, 9.6; height 3.5, 2.7. Stratigraphic Occurrence.—Skinner Ranch Formation; Bone Spring Formation. Localities.—Skinner Ranch: USNM 722-1. Bone Spring: USNM 728f. Diagnosis.—Rectangular Heteralosia of medium size, low convexity, and fine spines. Types.—Figured specimens: USNM 151274a-c. Described specimen: USNM 151270. Comparison.—This species suggests H. vidriensis, new species, but differs in its less convex profile, squarer outline, and sulcate anterior. Subfamily CTENALOSIINAE Muir-Wood and Cooper, 1960 Strophalosiidae with numerous small teeth and sockets along the hinge of both valves; obscurely costate anteriorly, brachial valve and pedicle valve rugose, with no spines. Genus: Ctenalosia Cooper and Stehli, 1955. Since its description the range of this interest- ing genus has been extended both geographically and stratigraphically. It is now known from the Bell Canyon Formation and the China Tank and Appel Ranch members of the Word Formation as well as the Getaway Member of the Cherry Canyon Formation where it is common. An unusually large species has been taken from the Park City Forma- tion in Wyoming. A primitive member occurs in the Neal Ranch Formation. Genus Ctenalosia Cooper and Stehli, 1955 Ctenalosia Cooper and Stehli, 1955:470.—Muir-Wood and Cooper, 1960:91. Small Strophalosiacea attached by most of ven- tral surface; usually wider than long and plano- convex to slightly biconvex; hinge usually narrower than midwidth; anterior commissure with mod- erate dorsal fold. Spines commonly of rhizoid type but rarely ornamental, located on cardinal ex- tremities and umbonal slopes. Anterior unattached part of pedicle valve marked by subdued costellae. Brachial valve marked by concentric undulations and obscure radial costellae. NUMBER 19 803 Pedicle valve somewhat saucer-shaped but with anterior part strongly deflected in dorsal direction; interarea moderately long, pseudodeltidium flat. Brachial valve operculiform, with short interarea. Pedicle valve interior with hinge-line denticulate, teeth small and protruding; myophragm prominent, dividing somewhat heart-shaped elevated adductor platform; diductor scars flabellate. Brachial valve with hinge margin marked by row of deep pits or sockets for teeth of pedicle valve under short interarea; cardinal process small and narrow, at right angles to valve surface or at oblique angle; shaft moderately long, indented me- dially by groove; myophore with wide median lobe but lateral lobes reduced and laterally compressed, adductor field small, usually deeply impressed and commonly excavated anteriorly; breviseptum short; brachial ridges large, occupying most of lateral areas; median groove margined by elevated inner walls of brachial ridges. Type-Species.—Ctenalosia fixata Cooper and Stehli (1955:471, pi. 52, A: figs. 1-16). Discussion.—Ctenalosia is a genus of small bra- chiopods having the general aspect of Heteralosia. Except for small external differences the two are readily confused. Heteralosia is the only Permian genus with which Ctenalosia is likely to be mis- taken and the two occur together at several lo- calities. Externally the two genera may be distin- guished by the fact that Ctenalosia has no ornament spines whereas those of Heteralosia are prominent. Furthermore, the anterior surface of Ctenalosia is commonly costellate but that of Heteralosia is usu- ally without costellae. The major differences are on the inside of the two genera. Ctenalosia is readily recognized by the posterior margin of either valve; the pedicle valve has a row of teeth and the brachial valve a row of sockets. Heteralosia has no articulation other than the normal pair of teeth and sockets with which most Strophalosiacea are provided. Another distinguishing feature of Ctena- losia is the prominent anterior fold and sulcus, not developed in Heteralosia. Several details of the anatomy of Ctenalosia may be advantageously discussed. In specimens favorably preserved, especially those growing on a flat surface, the pedicle valve palin- trope is well developed. It is fairly long and flat, the pseudodeltidium scarcely disturbing the even surface. The delthyrium is moderately large, but is usually covered almost completely by the flat pseu- dodeltidium. In some specimens the pesudodelti- dium is marked by a narrow smooth area at about its center, but generally its outline is difficult to determine. Generally the sides of the delthyrium of Cten- alosia are not marked by a tooth at each anterior angle as in other Strophalosiacea. Each is rather marked by a row of irregular teeth, the largest of which may appear at almost any point along the hinge line. The teeth are irregular, triangular, gen- erally pointed projections lying in the tissue that supports the palintrope. Thus they jut out just under (anterior to) the edge of the palintrope. In some instances the smaller teeth are near midvalve bounding the delthyrium but in others smaller teeth are scattered in the row. Two or more teeth may grow together to form a single large tooth; in other places, where a tooth has failed to develop, a gap may appear in the row. In some, the teeth are closely crowded, in others, widely separated; the two conditions depending on factors of growth, crowding, and age. The adductor platform of the pedicle valve is variable, as are all other features of this genus. In the young, the myophragm appears as a low, rounded ridge with faint thickenings. The myo- phragm maintains its prominence in all growth stages and no specimen was seen in which it had been engulfed. In old age the muscle platform in some specimens is excavated anteriorly so that it hangs over the median part of the valve, the myo- phragm becoming exaggerated and projecting ver- tically as a real septum. The sockets in the brachial valve are as irregu- lar in size as the teeth. Like the teeth, they are located in the secondary tissue just under (anterior to) the palintrope. In perfectly preserved specimens the sockets underlie the palintrope, but in many specimens the palintrope has been stripped away and the sockets appear as a serrated margin, the walls between the sockets standing up as ridges. In the young of Ctenalosia the cardinal process is narrowly compressed and the myophore is no wider than the shaft. The anteroventral surface of the shaft is marked by a deep groove which divides the shaft longitudinally into two equal rounded bars. The groove terminates near the distal end of the cardinal process, where the myophore is somewhat flattened. Anteriorly the groove con- 804 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY tinues the full length of the shaft and onto the valve floor, where it separates two low rounded ridges. These extend anteriorly between the ad- ductor scars but diverge laterally at the anterior end of the scars and form an anterior bounding ridge to the adductor field in many specimens. The myophore of young specimens is narrowly compressed, but the median lobe is the widest of the three. The lateral lobes are tightly pressed against the median one, and the groove between is narrow. In some valves the lateral lobes overlap the median lobe. With age many specimens widen the myophore, and in a few specimens it becomes definitely trilobed, but the median lobe always re- tains its greater width. In young specimens the cardinal process is usu- ally at right angles to the valve floor, but with growth it becomes more erect relative to the floor; however, no specimens were seen where it had reached the perpendicular when the valve is viewed from the ventral side. The development of the cardinal process of this genus is as variable as that of all other attached productids, and the same patterns are discernible. Many specimens that had not yet attained full adult length and width nevertheless exhibit full adult interior characters. The adductor scars are deeply sunk and are surrounded by thickened rims. The myophore is thickened and expanded, and the bra- chial ridges are greatly exaggerated. On the other hand some of the largest brachial valves in the collection have a small underdeveloped cardinal process with a deep median groove, scarcely defined adductor scars, and only faintly developed brachial ridges. No basis for specific distinction could be discovered in these specimens.; consequently, it is concluded that the variations are induced by the accidents of living conditions favorable to some individuals, less so to others. The adductor field is as variable as the cardinal process. Usually the scars are deeply sunk in the tissue of the floor and consist of an anterior and posterior pair as usual. In some, even large shells, the scars are scarcely visible but this is unusual. It is commoner for them to be deeply sunk, and in well-nourished specimens they are defined by the ridges mentioned above. In a few, these ridges are excavated somewhat on the anterior side, and the adductor field then has the appearance of an ele- vated platform. The brachial ridge is another variously devel- oped feature of the brachial valve interior, from invisible in some large specimens to so strongly de- veloped that they form elevated ridges. In the ideally developed specimen the ridge originates on each side of the adductor field at the point where the anterior and posterior adductors meet. The ridge then swings anterolaterally and roughly par- allel to the lateral margin to make a narrow loop posteriorly at the edge of the sulcus (fold of the exterior), and then dying out just anterior to mid- valve. In some specimens the strongest parts of the brachial loop are the part parallel to the antero- lateral margin and that bounding the sulcus. The latter part is so strong and elevated in some that it lends considerable depth to the sulcus. The median sulcus as in most productids is not very deep. In Ctenalosia it is short, shallow and wide, commonly defined by the inner ridge of the brachial ridge. Externally the sulcus appears as a low fold, frequently not clearly discernible except for the emargination of the pedicle valve, in which a moderately deep sulcus is produced to match the dorsal fold. The growth of Ctenalosia is like that described for Heteralosia and other closely attached genera. Usually specimens that attach to broad, flat surfaces are likewise broad, with well-developed interareas and wide hinges. On the other hand specimens that attach to bryozoans, crinoid stems, or other round objects are generally narrow-hinged and have long interareas. Furthermore, rhizoid spine develop- ment is more scattered, the spines longer, and in many instances, stouter. The holotype of the type species is an example of a specimen attached to a narrowly rounded object. The rhizoid spines are scattered over most of the exterior of the pedi- cle valve. In one unusual specimen the posterior part of the pedicle valve and its anchor spines form a solid ring. Usually however, the cicatrix is broad, and the rhizoid spines form a fringe around it. A feature observed in a number of pedicle valves from USNM 728 may be due to burrowing organ- isms or may result from ingrowing spines. These are long tubes that generally extend from about the anterior end of the adductor field to a short dis- tance from the anterior margins. The tubes are generally straight; commonly they are fairly deeply buried near their origin, but emerge on the inner NUMBER 19 805 valve surface and extend along it roughly parallel to other spines. The exterior part of the spines is usually thin-walled and the apertures round. These suggest rhizoid spines that were engulfed by the growing shell and continued to flourish for some time as described in Waagenoconcha (Grant, 1966a, b). Perhaps, however, they represent other organ- isms that lived under the mantle of the brachiopod. In the latter case, irritation caused by the intruder would lead to the expectation that the brachiopod would have thickened the shell at these places and attempted to seal off or smother the "parasite." Ctenalosia fixata Cooper and Stehli Plate 197: figures 1-65 Ctenalosia fixata Cooper and Stehli, 1955:471, pi. 52A: figs. 1-16.—Muir-Wood and Cooper, 1960:91, pi. 31: figs. 17-25. Small, attached shells forming shallow to deep saucer; outline variable, wider than long or vice versa depending on substrate; hinge usually narrower than midwidth; sides rounded; anterior margin rounded to emarginate depending on age. Attached by umbo and anchored by ring of stout rhizoid spines. Surface of pedicle valve obscurely to moderately strongly costellate. Exterior of bra- chial valve without spines, wrinkled concentrically or with obscure costellae; infrequently with pattern of host impressed on exterior. Pedicle valve with most of umbonal surface oc- cupied by cicatrix in many specimens, thus form- ing shallow or deep saucer more elevated on anterior side than on posterior. Some specimens attached to round objects, productellid in outline, with strong and fairly even convexity in lateral profile, but with domed anterior profile. Anterior slope long and steep. Interarea moderately long, flat. Cardinal extremities reduced, usually partaking in fixation. Sulcus shallow but indenting front margin. Brachial valve variable, generally gently convex in lateral profile and broadly convex in anterior profile, but many specimens broadly concave in both profiles. Ears small and flattened, well defined but not prominent. Margin thickened and slightly deflected in dorsal direction. Fold low, externally not clearly defined in most specimens but deep and pronounced as sulcus internally. Interior of both valves as defined for genus. Measurements (in mm).— brach- ial maxi- valve mum hinge thick- length length width width height ness USNM 706c 124123a 7.0 6.3 8.1 4.7 3.2 2.7 (holotype) 124123b 6.9 4.5 7.0 4.3 3.0 2.4 124123d 6.2 ? 9.4 6.3 4.2? ? 152642a 9.0 ? 9.8 8.1 5.2 ? 152642b 6.4 4.8 8.0 6.4 3.8? 3.0 USNM 728 152643a 6.6 ? 8.9 6.6 2.8 ? 152643b 7.4 5.8 8.7 5.0 5.0 4.2 152643c 6.1 4.8 8.3 5.2 2.8 2.4 Stratigraphic Occurrence.—Cherry Canyon For- mation (Getaway Member), Word Formation (China Tank, Willis Ranch, and Appel Ranch members and lenses between the last two), Bell Canyon Formation (Hegler and McCombs mem- bers). Localities.—China Tank: USNM 706c. Lens: AMNH 512, 652; USNM 706b. Getaway: USNM 728. Appel Ranch: USNM 706d, 714o, 715i, 719z, 722t, 727j. Hegler: USNM 732a. McCombs: AMNH 409. Types.—Holotype: USNM 124123a. Figured par- atypes: USNM 124123b-i; 124161a. Measured para- types. USNM 124123b, d. Measured hypotypes: USNM 152642a, b; 152643a-c. Unfigured para- types: USNM 124123J, 124161b. Figured hypotypes: USNM 152642a, b; 154123; 154124a, b; 154125a-c; 154126a-c; 154127a-c; 154128a-k. Discussion.—Some important differences between the specimens from the Glass Mountains and those of the Guadalupe Mountains are evident. Speci- mens from the latter are generally more robust, with thicker shells and more positive structures in the interior. The Glass Mountains specimens are generally thin-shelled and the interior features are not as prominent as in most of the Guadalupe specimens. Nevertheless, the variation is so great in the specimens from both regions that some from the Guadalupe Mountains have the same delicate nature as those from the Glass Mountains. Some specimens from the Glass Mountains exhibit greatly thickened structures, such as the myophore of the cardinal process and the brachial ridges; however, the majority of specimens from that region are more 806 delicately constructed than those from the Guada- lupe Mountains. It is suggested that an ecological factor was operating in the two regions because no basis for separating species could be found on the exterior. This species is known only from the Getaway Member in the Guadalupe Mountains and is com- mon at only one spot. At USNM 728 ( = AMNH 512) it occurs in a sponge bioherm where it found congenial conditions and ample surface to fix it- self on the solid sponges. In the Glass Mountains Ctenalosia is usually fixed to other shells rather than to sponges. Furthermore, the bottom was a fine sandy lime mud in each of the Word limestone members. Generally, the fossil occurrences in these Word limestones represent thanatocoenose assem- blages of dead shells washed together. Ctenalosia has an odd distribution in these limestones; it is rare in the China Tank Member, but only a single specimen has been found in the Willis Ranch Member. Inasmuch as several tons of limestone from this part of the Word Formation were dissolved in the course of this study, the species is thus ex- tremely rare in that member. A fair number of specimens was taken from a lesser bulk of Word limestone (Appel Ranch Member). It is thus com- moner in this member but is, nevertheless, a rare shell. Ctenalosia primitiva, new species Plate 192: figures 26-34 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 701, specimens 151249a (holotype) and b (para- type), respectively: length 5.2, 4.8; brachial valve length 4.7, 4.1; width 6.6, 5.5; hinge width 5.3, 3.2; thickness 2.4, 2.7; height 3.0, 3.8. Stratigraphic Occurrence.—Neal Ranch For- mation. Localities.—USNM 701, 701d, 721g. Diagnosis.—Small Ctenalosia with incipiently denticulate hinge and ornament spines. Types.—Holotype: USNM 151249a. Figured paratypes: USNM 151249c, d; 151267. Measured paratype: USNM 151249b. Unfigured paratype: USNM 151249b. Comparison.—Small size and the strongly costel- late anterior free part of the pedicle valve, together with the incipient nature of the comblike teeth along the hinge, separate this species from other described forms. Furthermore, the interior of the brachial valve is rather heteralosiid without the median sulcus and without strong median ridges. Discussion.—This species is of great interest be- cause it combines characters of Heteralosia and Ctenalosia. The exterior surface of the free part of the valve is costellate like that of Ctenalosia, but has ornament spines like those of Heteralosia. The interior of the brachial valve is like that of Heteralosia. Missing inside the brachial valve are the strong adductor pits and the brachial ridges. The shaft of the cardinal process is not so long and is not connected to the breviseptum. This species probably represents an ancestral stage in the de- velopment of Ctenalosia. Small, strongly convex with small cicatrix of at- tachment; sides and anterior rounded; free surface costellate; anchor spines stout, but ornament spines long and slender. Interarea short. Brachial valve moderately concave, with maximum concavity to- ward anterior. Surface of brachial valve wrinkled, pitted, margin of larger specimens castellated to correspond to pedicle valve. Pedicle valve interior with few, poorly developed comblike teeth as well as normal teeth. Brachial valve interior with irregular sockets; cardinal process widely trilobed, shaft short. Sockets poorly defined. Septum low, highest anteriorly and reach- ing just beyond midvalve. Adductor field fairly wide. Measurements (in mm).—From locality USNM Ctenalosia rotunda, new species Plate 192: figures 20-25, 35-45 Small, with thick shell, subcircular in outline with well-rounded sides and anterior margin. Height not great; anterior exposed surface fairly strongly costellate. Hinge narrower than maximum width, at midvalve. Attachment surface variable but fairly large; interarea short. Teeth of pedicle valve large and few; sockets of brachial valve deep. Brachial valve unevenly convex and with anterior depres- sion parallel to margin in anterior part. Interior with large and ponderous cardinal process, short breviseptum, and large, elevated adductor plat- forms. NUMBER 19 807 Measurements (in mm).— brach- ial valve hinge thick- length length width width height ness AMNH 635 152645c 7.0 5.8 6.3 4.7 2.9 3.4 (holotype) 152645a 4.5 4.0 5.2 2.7 2.9 152645b 3.9 3.6 4.9 2.4 3.1 3.3 Stratigraphic Occurrence.—Bell Canyon For- mation (Hegler Member). Localities.—AMNH 635, USNM 732a. Diagnosis.—Small, thick-shelled Ctenalosia with round outline and a few large teeth. Types.—Holotype: USNM 152645c. Figured paratypes: USNM 152645b; 154121a, b. Measured para types: USNM 152645a, b. Comparison.—The three specimens available in- dicate a species smaller and thicker-shelled than C. fixata, with coarser teeth in the pedicle valve and larger, more elevated adductor platforms. Ctenalosia transversa, new species Plate 198: figures 1-19 Large for genus, wider than long and broadly elliptical in outline; sides narrowly rounded; anterior margin broadly rounded; pedicle valve attached by at least half its length. Free surfaces of pedicle valve marked by strong costae, about 7 in 5 mm at front margin; brachial valves generally with visceral disc region irregularly marked by rounded humps or interrupted costae; anterior margin with well-marked costae. Pedicle valve strongly geniculated, visceral disc region attached to hard surface, anterior trail por- tion free and extending at right angle or slightly obtuse angle from surface of attachment; anterior commissure marked by strong sulcus best shown at margin. Rhizoid spines forming ring around at- tached part; body or ornament spines long and aris- ing at low angle, few and scattered. Interarea mod- erately long. Brachial valve unevenly concave, visceral disc region usually slightly convex, trail geniculated at low angle, bent in dorsal direction. Anterior mar- gin with broad fold. Pedicle valve interior with short median ridge and moderately elevated, anteriorly thickened muscle platform. Teeth along cardinal margin long, pro- truding. Brachial valve interior with variable but long erect cardinal process having trilobed myophore. Cardinal process shaft usually indented. Median septum strong. Adductor platform thickened, an- teriorly free of valve floor. Sockets deep and prominent. Measurements (in mm).— brach- ial valve mid- hinge thick- length length width width height ness USNM 762 152644a 8.5 ? 11.7 7.7 2.4? ? 152644b 9.4 ? 12.7 6.9 3.0? ? 152644c 8.2 ? 11.3 7.9 1.3? ? 152644d 9.9 7.6 12.5 7.3 2.3 1.1? (holotype) Stratigraphic Occurrence.—Park City Forma- ation (Franson Member). Localities.—USNM 760, 762. Diagnosis.—Large, strongly cosíate Ctenalosia with long trail. Types.—Holotype: USNM 152644d. Figured par- atypes: USNM 152644a, c, e, g, h; 154134a-c. Mea- sured paratypes: USNM 152644a-c. Unfigured para- types: USNM 152644b, f. Comparison.—Ctenalosia fixata Cooper and Stelili is the only species to which this one can be compared. It is a much larger and more strongly ornamented species than the Glass Mountains and Guadalupe Mountains form. A stouter cardinal process and more thickening of the interior of both valves characterizes C. fixata but the brachial valve adductor platform is not as free at the anterior end as it is in C. transversa. Furthermore, the thickening of the muscle platform in the pedicle valve of C. transversa is not so strong as that of C. fixata. Discussion.—The early stages of this species are low and slightly convex, the pedicle valve spreads gradually over the surface of attachment until it attains a length of 5 mm. or more, provided the substratum will permit. Growth then takes place at an angle to the subsurface. This angle may be initially more than a right angle, but as growth continues, the anterior curves sufficiently for the trail to approximate a right angle from the attach- ment surface. Anchoring in the early stage is by 808 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY cementation and strengthening with rhizoid spines which form a ring around the young Ctenalosia. After the trail is well developed, body spines, arising at a low angle to the trail surface, curve anterodorsally and undoubtedly hung over the aperture. The folding of this shell, as in C. fixata, is variable but is one of its distinctive features. This generally originates as a slight wave of the anterior margin toward the dorsal valve but it deepens as the margin grows away from the surface of attach- ment. In occasional specimens it may become so strong as to create an elongate tongue on the pedicle valve. The most interesting structure of the interior of the pedicle valve is the teeth, which are generally long and slender but develop interesting aberra- tions. Usually the tooth is fanglike, slightly curved toward the posterior, fairly sharply pointed, and about .25 mm in length, but, in rare shells at- tains a length of 1 mm. When viewed from beneath the palintrope, the teeth in some specimens form distinct ridges; in others they have been covered by shell substance and only the articulating or free parts are visible. Several specimens show interesting abberations in which teeth have been coalesced by shell material just beneath the palintrope edge to form an ir- regular plate or extra socket. In another, these secondary structures form a second set of irregularly shaped teeth under the primary set. The development of the myophragm, the small plate on the adductor platform, is as variable as the development of the platform itself. In some speci- mens it is strong and approximates a septum, but in others it seems not to have formed. This seems not to be a matter of preservation or poor silicification, because no trace of the structure is to be seen in these shells. Although the platform varies from scarcely perceptible to widely triangular and strongly elevated, no specimens were seen in which the adductor platform is anteriorly excavated. The interarea of this species is fairly long and is completely flat; the pseudodeltidium is flush with the sides of the interarea, and itself flat and difficult to differentiate. Usually it is thin and is commonly crushed out to form a gap. When uncrushed, its position is clear by a gap in the battery of teeth. Most specimens of the brachial valve show the posterior as a row of pegs with spaces between them. These specimens are imperfect. In perfect condition the sockets appear as a horizontal row of deep pits just anterior to the posterior margin. Usually how- ever, the posterior margin is eroded away, leaving the space between the sockets as pits. It is also common for the posterior dorsal surface to be so worn that the sockets appear as holes through the posterior of the valve. The cardinal process is long-shafted and slender or stout. In young specimens it usually extends at a right angle to the valve directly into the body cavity, but in older specimens it rotates to stand at about 45° to the valve surface. The anterior part of the shaft in young specimens is excavated, but in older forms it may be completely solid or may retain the elongated excavation. The myophore is notable for the large size of its median lobe. This is usually wider and longer than the lateral lobes and protrudes beyond the lateral lobes. In some specimens the lateral lobes are closely pressed to the median lobes but in others they are more flaring which emphasizes the trilobation. The adductor platform is strongly excavated anteriorly, the lobes to which the anterior adductor pair are attached hanging free in the valve. The posterior scars are located somewhat outside and behind the anterior scars and are generally not thickened, as they are attached to the valve floor. The degree of anterior excavation is variable, but is noticeable in all specimens and extreme in some. The breviseptum is strongly developed anteriorly, but is usually buried at its proximal end in the tissue of the adductor platform. Brachial ridges are only indistinctly developed in this species. Ctenalosia transversa most commonly occurs attached to the brachial valve of Bathymyonia, but has been seen adhering to Xestotrema pulchrum and Derbyia. It also clings rarely to bryozoa. Family TEGULIFERINIDAE Muir-Wood and Cooper, 1960 Strophalosiiacea having an obliquely conical pedicle valve attached by its apex and anchored by rhizoid spines; pseudodeltidium and interareas ab- sent; brachial valve opercular; cardinal process long-shafted, bilobate, no alveolus. Little or no development of apical cystose shell. NUMBER 19 809 Genera in West Texas: Teguliferina Schuchert and LeVene (1929), Acritosia Cooper and Grant (1969). This family appears in the Pennsylvanian but becomes abundant in the Neal Ranch Formation, where there are small patch reefs or bioherms of them. It is represented by Acritosia in the Skinner Ranch Formation, but the family does not range higher than the Skinner Ranch except for A.? vestibula, new species, from the Road Canyon, tentatively referred to that genus. Genus Teguliferina Schuchert and LeVene, 1929 Tegulifera Schellwien (not Saalmüller, 1880, insect), 1898: 362; 1900b:59. Teguliferina Schuchert and LeVene, 1929:121.—Stehli, 1954: 330.—Muir-Wood and Cooper, 1960:92. Planispina Stehli, 1954:331.—Muir-Wood and Cooper, 1960: 94. Small to medium, forming low oblique cones or (in later species) rounded cones with eccentric apex. Brachial valve opercular and usually lying deeply within cone, to form a vestibule, at a steep angle to the vertical. Exterior surface usually with strong growth lines or ragged concentric lamellae representing resting stages in growth; surface usually with fine concentric growth lines and, in some species, obscure radial lines. Shell attached by apex and anchored by smooth, round spines in young stages, but commonly joined by flattened webs be- tween them or with broad flattened spines and sheetlike expansions. Inside of anterior margin of pedicle valve provided with stout protective spines on ventral side partially or almost wholly covering opening. Pedicle valve with very narrow, straight hinge and short triangular interarea commonly covered by shell layers. Sockets for articulation of brachial valve lying at anterolateral extremities of hinge usually narrow and deep; aulacoterma strong and forming prominent ridge around valve interior. Muscle area small, with anterior median callosity divided by septum commonly forked anteriorly; adductor scars elongate; diductor impressions sub- flabellate; interior spine extensions common, especially on sides. Brachial valve pyriform in outline, narrow hinge having narrow ginglymus (?); articulating processes forming narrow, rounded projections at hinge extremities; lateral ridges strong, forming marginal thickening; cardinal process long-shafted, with narrow or slightly expanded trilobed myophore; median ridge supporting cardinal process and ex- tending to middle of adductor field; breviseptum short, extending anterior to midvalve, in some species uniting with median ridge to form long continuous ridge. Adductor scars elongate. Brachial ridges indistinct. Type-Species.—Tegulifera deformis Schellwien (1898:362). Diagnosis.—Small, obliquely conical Tegulife- rinidae having weblike, flat expansions between the rhizoid spines. Comparison.—The peculiar weblike expansions between the rhizoid spines of this genus separate it from all others of the family. It differs from Acritosia in its generally smaller size and strictly apical position of the articulation. It is easily distinguished from Taphrosestria by the squat form of that genus and the fact that anastomosing spines cover the entire aperture of Taphrosestria. Slehli (1954:331) created the genus Planispina for conical shells having the internal and external features of Teguliferina, and, in addition, flat webs between the rhizoid spines. He regarded the teguliferinids with rhizoid spines having a round cross section as the true Teguliferina. He had apparently no specimens of the European species and consequently was not aware of the flattened rhizoid spines and webs. These features are visible on a number of specimens of unsilicified tegulife- rinas from the Pennsylvanian of Texas, Kansas, Illinois, and Oklahoma, as well as on European specimens. The feature seems to be characteristic of Teguliferina and thus Planispina becomes a subjective junior synonym of Teguliferina. Discussion.—Teguliferina is one of the common- est inhabitants of the Wolfcampian and late Penn- sylvanian bioherms. In some of them it occurs in such numbers that it makes up most of the bioher- mal structure. Such masses give an excellent oppor- tunity to study the clusters as well as the individual. The clusters are composed of young and old speci- mens thus making it possible to remark on the on- togeny of the various species. The mode of growth is one of the distinguishing characters of Teguliferina. The junction point of the two valves remains apical throughout the life 810 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY of the animal, although the form of the cup radi- cally changes from an oblique to a nearly vertical cone. The posterior side thus develops a long hood that envelopes the hinge region. This hood is internally strongly papillose and must have been covered by an extension of the mantle. In Teguliferina no protective spines have been observed on the posterior side to protect or cover the hinge region. On the anterior side, however, the cup is well protected by stout spines, usually vari- able within a single species. In many individuals these spines merely form a ring around the anterior side. They commonly project nearly vertically or at a moderate angle to the exterior surface. In others they are massive and stout and nearly cover or completely cross the opening of the vestibule. The spines are commonly single but many of them bifurcate, while others may join at some distance from the margin. These protective spines are so variable in many species that they do not afford a reliable specific character. The young Teguliferina reach a fair size before the oblique cone starts to equalize its anterior and posterior sides. In the young specimens the anterior side is strongly elevated and has a rim of protective spines inside the anterior rim. A hood starts to form over the hinge region and this, once started, grows rapidly to equalize the two sides of the cone. When the hood is fully grown it attains the same height as the posterior side. The hood is usually strongly papillose on its inner surface, the papillae approximating stubby spines in some specimens. A cone-in-cone effect results from a series of apertures arising one within another probably by contraction and expansion of the mantle in the upward growth of the animal. Some specimens show this effect very strongly, and have a very ragged appearance as a consequence of it. The cone is anchored by spines which, in the young, are round and delicate. As the cup continues its growth and need for more solid anchoring arises, the spines are further reinforced by develop- ment of webs between them and external sheets of shell substance that may also serve as an anchoring medium. This material originates as a spine, starting as a spine opening and expanding anteriorly and laterally and frequently branching in its growth. The sheets commonly wrap around or partially envelope spines already formed. It is as though a thick viscous liquid was squeezed out of a narrow opening and expanded over all irregularities in its way. The sheetlike substance appears to be con- nected with the external layer and is concentrically marked similiar to the exterior of the cup. The development of the webs is not uniform among the species; in T. boesei they appear at about the time the posterior hood begins to develop, after the individual had been long attached by normal round spines. In the Gaptank species the webs appear at a very early stage, and no round spines were seen. The most interesting features of the pedicle valve are those of the hinge region which is unlike the normal brachiopod because the sockets of articula- tion are located in this valve. The inner cavity of the pedicle valve is pear-shaped, narrowing poste- riorly. At the narrowed end are the two small shelflike plates (or palintrope) separated by a triangular opening into which the lophidium of the cardinal process is inserted. The anterior edges of the shelflike plates are the hinge edge and terminate laterally against the valve wall. The sockets for the insertion of the articulating process are located at the anterolateral edge of the triangular plates. The surface of the palintrope constitutes an interarea like that of normal brachiopods. A few exfoliated specimens show this interarea as a small triangular surface at the beak and with a small cover or elytridium over the posterior part of the triangular opening. Thus this structure, except for the sockets which are aberrant, is like that of the Strophalo- siidae or Aulostegidae. The palintrope is supported by shell thickening that forms a ridge on each side of the narrowed posterior part of the valve and extends antero- laterally around the entire inside of the cup. This ridge is the aulacoterma. It is thickest posteriorly and in some specimens is longitudinally divided for some distance. This shelf forms the resting place of the sides of the brachial valve. At the posterior, narrowed end of the pedicle valve, opposite the curve forming the narrowing, is located a pit of variable dimensions, the surface of which is smooth or papillose. In some specimens this pit appears to be completely absent; in others it is a conspicuous feature. Its presence or absence appears to have no significance in the formation of species. A similar feature appears in richthofeniids. The muscle scars of the pedicle valve are not gen- erally strongly impressed. The muscle field occupies the narrowed end of the cup and is usually some- NUMBER 19 811 what thickened especially at the anterior. A me- dian myophragm is generally present which forks narrowly at the anterior end. The adductors are elongate and the diductors subflabellate. A feature common in productaceans, and also in richthofeniids, is the presence of spine bases on the interior of the cup. These are fairly common, especially on the lateral walls of many specimens. In the younger individuals these appear as small holes, but in older and larger forms they have distinct rims around them. The brachial valve is also pyriform in outline and fits closely into the small end of the pedicle valve, the expanded anterior part overlying the aulaco- terma. The hinge is extremely narrow and straight. An interarea, or ginglymus, forms the posterior margin. On each extremity of the hinge is a small triangular lateral projection which is the articulat- ing process. This fits into the socket at the antero- lateral extremity of the pedicle valve palintrope. In some specimens the socket is further strengthened by a thickening on the margin of the aulacoterma where it terminates posteriorly at the socket. The lateral margins of the brachial valve, especially at the reentrant just anterior to the hinge where it is narrowest, is strengthened by a thickening. This extends anterolaterally along the margin of the expanding shell to about midvalve, where it gen- erally dies out. These marginal thickenings cor- respond to the lateral ridges of the normal produc- tid shell. The thickening is strongest and highest just anterior to the articulating process where the shell is narrowest and and probably helped in the articulation of the valves. The cardinal process is erect, elongated, long- shafted, and bilobed in ventral view. In side view it is at an angle to the valve surface. The myophore is generally moderately lobed, with the lateral lobes moderately expanded but the median lobe narrow. The lateral lobes are moderately deeply grooved as usual in productids. The shaft bears a median groove. The cardinal process is buttressed by median elevation frequently consisting of two low parallel ridges that extend between the adductor scars. This unites with the breviseptum to form a single long ridge, and is separate from it. The breviseptum is usually short and terminates anterior to midvalve, but posteriorly extends between the adductors. The anterior pair of adductors is the larger of the two. In T. conida the scars are large and somewhat thickened but in some individuals of T. boesei they are long and narrow and moderately deeply inserted. The anterior slope of the valve is marked by large, stoutly pointed endospines of varying number depending on the species. Growth.—The growth of the cup of Teguliferina is one of the main distinctions between this genus and the richthofeniids. The younger Teguliferina forms a very oblique cone in which the brachial valve is roughly parallel to the ventral side of the cone. The oblique position of the brachial valve is maintained throughout life, no matter how elon- gated the cone becomes. The cone is attached at the apex, but this part of the shell does not migrate aperturally as in the richthofeniids. Teguliferina boesei R. E. King Plate 203: figures 4-25; Plate 204: figures 1-30; Plate 207: figures 28-38 Teguliferina boesei King, 1931:96, pi. 27: figs. 14-16. Planispina boesei (R. E. King) Muir-Wood and Cooper, 1960, pi. 9: figs. 11-17. Adult forming fairly symmetrical cone except for apex, that -is twisted or deformed; young forming oblique cone. Height about three fourths of width. Posterior side of cone flattened, anterior side rounded. Apex usually deformed, attachment sur- face generally small. Initial and young anchor spines, rounded and slender; later attachments with strong broad webs forming after adulthood is reached. Anterior surface obscurely costellate. Pedicle valve with strong aulacoterma and prom- minent concave, shelflike areas posterolaterally. Hinge very narrow. Hood strongly developed in early adultstage. Protective spines on anterior side slender to moderately stout, numerous, not com- pletely covering the aperture. Outer anterior mar- gin not strongly reflected. Brachial valve gently concave to flat; surface finely papillose. Widest at midvalve, with the sides narrowly rounded and anterior broadly rounded. Pedicle valve interior with lightly impressed muscle scars; interior spines moderately developed. Brachial valve interior with large and erect cardinal process, long breviseptum; no cardinal process buttress, and elongate adductor scars. Endospines few and large. 812 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 701d 151347a 13.4 11.1? 16.0 3.0? 13.4 4.1 2.8 151347b 12.6 10.1? 19.0 3.0? 13.4 5.5 3.8 151347c 14.4 12.5? 20.5 2.9? 12.2 6.2 3.8 151347d 16.9 13.1? 20.0 3.2 14.6 6.9 4.2 151347e 15.6 11.7 22.0 3.3? 14.4 6.8 4.8 151347Í 17.0 12.2? 21.4 3.5? 15.6 8.7? 5.5 151347g 18.7 12.6 28.0 2.8 16.6 8.8? 6.5 151347h 17.6 11.0 22.0 3.1 18.8 9.0 5.1 151347Í 14.7 11.9? 20.0 ? 19.4 10.4 7.6 151347J 18.2 11.0 21.0 3.5? 23.0 15.0 4.4 151347k 18.5 12.6? 23.0? ? 20.0 10.5 7.0 1513471 15.0 ? 24.0 ? 17.2 16.0 6.9 151347m 19.1 ? 28.0 ? 20.6 18.0 9.6 151347n 15.8 ? ? ? 20.1 14.0? 6.0 USNM 701h 151349a 12.0 ? 23.0 ? 17.1 12.6 7.5 151349b 15.2 10.6? 21.0 2.9 17.1 9.6 6.5 151349c 13.2 10.3? 20.0 2.8 13.6 7.8 3.9 151349d 11.6 9.0? 14.0 2.0 12.9 7.0 3.5 151349e 9.4 7.4 13.0 2.7 9.5 3.8 3.5 151349Í 7.9 5.0 9.0 ? 6.8 2.9 2.3? USNM 701k 151352a 18.4 13.0? 29.5 ? 26.3 18.4 ? 151352b 15.9 ? 26.0? ? 20.6 17.8 ? 151352c 14.0 10.7? 15.0? ? 19.0 9.3 4.7 151352d 14.2 10.2 16.0 1.8 15.1 4.7 3.9 151352e 10.7 8.0 15.0 2.8 13.0 5.0 2.8 USNM 712w 151362a 13.7 ? 30.0 ? 20.0 18.0 6.9 151362b 18.7 11.8 25.0 2.1 19.0 11.9 5.3 151362c 13.0 9.3 17.0 2.5 12.8 5.4 3.5 Stratigraphic Occurrence.—Gaptank Forma- tion (Virgilian), Gaptank Formation (Uddenites- bearing Shale Member), Neal Reach Formation; Lenox Hills Formation. Localities.—Gaptank: USNM 700g, 70ly. Ud- denites: USNM 700i, 701e, 701f, 701p, 701q, 701t, 701v, 701x, 702j, 702n, 702q, 702r, 703p, 703x, 713b, 713o. Neal Ranch: USNM 701, 701a, 701a3, 701c, 701d, 701h, 701k, 701-1, 712w, 713h, 715b, 715e, 721g, 727d, 727e, 742c. Lenox Hills: USNM 705, 705k, 705m, 705s, 707j, 709t, 715, 716r, 723r, 737u. Diagnosis.—Fairly large Teguliferina with deep cups in the adult and prominent web-like spine attachments. Types.—Holotype: YPM 12829. Figured para- types: YPM 12661a, b. Figured hypotypes: USNM 151346a-c; 151347n; 151352d, e; 154091a-c, e-i; 154092a-h; 154093a-d, f; 154094a, c; 154095a, b; 154101a, b; 154110. Measured hypotypes: USNM 151347a-n, 151349a-f, 151352a-e, 151362a-c. Unfi- gured hypotypes: USNM 151347a. Comparisons.—It is almost impossible to identify most young specimens of different species of Teguliferina. It is usually necessary to have the full growth series and also enough adult specimens to give a good idea of the full range of variation. As identified by us this species is represented in the collection by many hundreds of specimens of all sizes and a full range of variable adults. In its fully grown form this species is unlike T. armata of the Pennsylvanian of Illinois, Texas, and Kansas, which is fairly common in King's bed 10 of the Gaptank Formation (USNM 700, 700a) at the base of the hills 23 miles north-northeast of Marathon. Adult T. armata has a low, oblique cup with little or only moderate development of the hood. Com- plete cups rarely attain a height over 12 or 13 mm. NUMBER 19 813 Teguliferina boesei attains a much larger size and the adult cup is usually much deeper. Teguliferina kansasensis Girty attains a size equal to that of T. boesei but the three specimens of this species now known do not permit adequate com- parison. All the specimens have a fairly broad apical region and form large, rapidly expanding cups, far more expanded and irregular in form than those of the majority of T. boesei. Teguliferina conida (Stehli) is a well-formed and rounded cup, in profile suggesting a large T. boesei. It is, however, usually much larger; its young stage is generally more spreading and open than that of T. boesei, which is oblique and generally pointed at the apex. The shell of T. conida is much stouter and the spines more robust than those of T. boesei. Of European species, T. boesei is most like T. deformis (Schellwien), type-species of the genus. The latter is commonly preserved in a hard mas- sive reefy limestone which makes comparison with silicified material difficult. The figures by Schellwien indicate a less robust species than the Glass Mountains one, seldom attaining the size and spaciousness of the Texas species. Discussion.—Six localities in the Glass Mountains have yielded large collections of this species. Each was apparently the site of bioherms on which Teguliferina dwelt in abundance. Considerable variation may be seen among the specimens from each locality and among those from different local- ities. For example specimens from approximately the same levels at USNM 701 h and 701k are much more delicate than the robust forms from USNM 712w. In spite of all the variables only one species seems to be represented from the Uddenites zone to the lower part of the Skinner Ranch Formation. Specimens from USNM 701 are generally more robust and solid than those from other localities. The explanation may be the difference in strati- graphic level, those from USNM 701 coming from the upper part of the Gray Limestone Member (bed 2 of P. B. King). Like the adults, the young of this species are extremely variable; forms that are transverse are found side by side with elongate individuals. These variable young produce variable adults. Further- more, no rule was discovered as to the size when the adult characters of protective spines and the beginning of a vestibule were initiated. These features appeared at lengths between 10 and 20 mm, but mostly at about 15 mm. Specimens smaller than 10 mm generally do not have spines or a vestibule; however, specimens slightly above this length may develop protective spines, but the vestibule usually developed later. Some specimens attained a length of 20 mm without developing either a vestibule or the protective spines, but these are unusual. That Teguliferina in the late Pennsylvanian and early Permian of the Glass Mountains favored a biohermal environment is clear from the Glass Mountains collections. Specimens in the shales of the Uddenites-bearing Shale Member of the Neal Ranch formation are rare and usually are not well-preserved. Most show evidence of transporta- tion. Specimens are abundant in the limestones, commonly in masses or clusters but these do not retain their coherence when decalcified. Neverthe- less, fairly large specimens showing the clustering habit have been recovered. Large specimens of Teguliferina in the Uddenites- bearing Shale Member are referred here to T. boesei. These include large forms found with Scacchinella primitiva in the Virgilian (?) bioherm south of the Arnold Ranch (USNM 700g.) Bio- herms of the Neal Ranch Formation abound in this species, but it is rare in the Lenox Hills Formation in which few silicified specimens were found. Inasmuch as the Lenox Hills formation is mostly conglomerate, specimens in it are loose or have drifted from nearshore bioherms. Teguliferina compacta, new species Plate 207: figures 1-10 Small, thick-shelled, solid, forming well-rounded cones with eccentric apex; posterior side generally slightly or markedly flattened; anterior side rounded; cup opening commonly narrowed and covered by few stout protective spines. Cone-in- cone effect strong; successive rims preserved as ragged lamellae. Attachment surface small. Rhizoid spines stout, bound by flat webs. Interior and bra- chial valve not known. Measurements (in mm).—From locality USNM 705r, specimens 151370a (holotype), b, and c, re- spectively: length 12.8, 14.8, 15.5; surface length 20.0, 16.0, 21.5; width 12.2, 18.2, 18.2; height 15.0, 16.4, 15.0?. Stratigraphic Occurrence.—Skinner Ranch Formation (top); Hess Formation (Taylor Ranch Member). 814 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Localities.—Skinner Ranch: USNM 705r. Tay- lor Ranch: USNM 702d, 702e, 723-1. Diagnosis.—Small, compact Teguliferina with ragged exterior. Types.—Holotype: USNM 151370a. Figured paratypes: USNM 151370b, c. Measured paratypes: USNM 151370b, c. Comparison.—The thick shell, low cone, and stout rounded form of this species, with the few protective spines over the cup, separate it from any of the Texas or European forms. Discussion.—This species is rare and is not favorably preserved because it is generally covered and often filled with gray siliceous material that is interpreted to be silicified algae that have grown over the dead shells. These algae make it difficult to recover complete specimens and may be the rea- son that the dorsal valve has not yet been seen. Teguliferina conida (Stehli) Plate 89: figures 31-33; Plate 205: figures 1-35; Plate 206: figures 1-43; Plate 309: figures 7-14 Planispina conida Stehli, 1954:332.—Muir-Wood and Cooper, 1960, pi. 9: figs. 18, 19. Large thick-shelled Teguliferina broadly oblique in young but forming misshapen cone in adults; aperture of cone flattened to concave on dorsal side; place of attachment varying from point to broad patch; apex usually distorted. Growth cylindrical after development of hood. Anchor spines stout and round in young, strengthened and partially covered by webs and sheets of shell tissue. Surface mostly concentrically marked except on dorsal side, which is obscurely costellate in some specimens. Anterior side with strong cone-in-cone development. Pedicle valve with stout protective spines on an- terior side, varying from oblique and single to branching and occasionally anastomosing. Hood formed after attainment of maximum width, usually flattened to concave; anterior side strongly convex and rounded. Lip of cup not greatly expanded. Brachial valve widely pear-shaped and with short posterior neck; hinge narrow. Surface varying from slightly convex to gently concave; sides narrowly rounded; anterior margin broadly rounded to sub- truncate. Pedicle valve interior with muscle area moder- ately to strongly thickened; internal spines numer- ous and large. Brachial valve interior with large cardinal pro- cess; buttress ridge strong; breviseptum strong and anteriorly elevated; adductor scars elongated; en- dospines few and large. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 705a 151375a 17.4 ? 30.0 ? 24.8 21.1 ? 151375b 20.0 14.1 27.0 2.9 23.8 15.8? ? 151375c 19.4 12.0? 32.0? ? 20.6 17.2 6.7 151375d 25.1 11.6? 31.5 3.5? 26.9 18.0 7.4 151375e 22.3 13.0 27.0? 3.6 23.2 14.3 6.4 151375f 16.8 ? 26.0 ? 22.3 15.2 ? 151375g 21.0 15.0 27.0 3.9 22.1 10.5 6.1 151375h 16.0 11.0? 22.0 3.3? 18.9 11.2 5.0 151375Í 19.0 13.3 24.0 4.0 23.6 10.7 2.1 USNM 728£ 152686a 16.0 12.0 18.0 4.9 19.7 6.0 4.0 152686b 14.0 8.3? 25.0? ? 20.0 14.4 6.1? 152686c 18.6 13.7? 27.0 3.5? 20.7 17.0 8.0 AMNH 625 123889 20.6 ? ? ? 22.6 18.8 ? Stratigraphic Occurrence.—Bone Spring For- mation, Skinner Ranch Formation (base), Cibolo Formation (Breccia Zone of Udden). Localities.—Bone Spring: AMNH 625, 629, 631, 632, 696; USNM 725c, 728e, 728f, 746. Skinner Ranch: USNM 705a, 707b, 709v, 714p, 715v, 720e, 724p, 733r. Cibolo: USNM 728-1, 738r. Diagnosis.—Stout, thick-shelled Teguliferina NUMBER 19 815 with strong cone-in-cone effect and ragged posterior sides. Types.—Figured hypotypes: USNM 123889; 151375a, c-e, i, j; 155149; 154096a-h, j, m; 154097a-d; 154098a, b; 154099a-c; 154111. Measured hypotypes: USNM 123889; 151375a-i; 152686a-c. Comparison.—Differences between T. conida (Stehli) and T. boesei R. E. King appear in young and old specimens. The young of the former are usually rounder and more open than those of T. boesei, and much less oblique. Furthermore, the appearance of the hood and protective spines ap- pears to take place at an earlier time or smaller size than in T. boesei. Although adults of both species have a similar habit, the cup of T. conida attains a much larger size and a greater diameter. Furthermore the protective spines are commonly larger and thicker than those of T. boesei. The cone-in-cone feature in the shell growth is more developed in most specimens of T. conida than in T. boesei and produces a shell with a ragged dorsal side. This feature occurs in most species of Teguliferina but it is especially marked in T. conida because of its large size and compact form. Discussion.—Teguliferina conida was described by Stehli (1954:332) under the generic name of Planispina, in allusion to the prominent webs on the spines. Inasmuch as these occur in the Penn- sylvanian species and also the European type species, they do not constitute a valid generic charac- ter in this case. Teguliferina conida is identified in the Glass Mountains in the Scacchinella zone (base of Skinner Ranch Formation), as well as in the Bone Spring Formation of the Sierra Diablo. Speci- mens in the Glass Mountains attain a somewhat larger size and more robust form but other features appear to be alike, making separation as different species unlikely. Teguliferina parva, new species Plate 207: figures 11-18 Small, forming posteriorly flattened cones having length and height about equal. Hood margin some- what flattened; spines on anterior inside margin numerous, moderately stout and inclined away from aperture; sides narrowly rounded. Surface with pos- terior side ragged, anterior side fairly smooth. An- chor spines of young specimens round, slender; older specimens with well-developed sheets of rhi- zoid tissue forming webs between spines. Pedicle valve with apex misshapen, attachment surface varying from small to nearly entire pos- terior surface. Ragged zone on posterior side ap- proximating half height of adult, having many closely crowded lamellae. Aulacoterma thick; pos- terolateral concave areas large. Brachial valve compressed, pear-shaped, with very narrow hinge and narrowed apical region. Sides narrowly rounded and interior broadly rounded. Pedicle valve interior with very narrow hinge; muscle scars not strongly impressed. Brachial valve interior with large, erect cardinal process, no median buttress ridge to cardinal process; long brevisep- tum; elongate adductor scars. Few endospines. Measurements (in mm).—Teguliferina parva, new species: brachial surface hinge length valve length length width midwidth height thickness USNM 761 151372a 9.9 ? 15.0 ? 12.7? 9.7 ? 151372b 11.4 ? 21.0 ? 16.0 10.4 ? 151372c 11.3 ? 15.0? ? 14.8 11.0 ? 151372d 9.9 7.3 13.5 2.8 14.2 6.5 4.0? 151372e 10.2 8.2 13.5 2.6 14.9 5.5 3.6 (holotype) Stratigraphic Occurence.—Wolfcampian (Red Eagle Limestone). Location.—USNM 761. Diagnosis.—Small Teguliferina with flattened cones and wide brachial valves. Types.—Holotype: USNM 151372e. Figured para- types: USNM 151372a, c, f. Measured paratypes: USNM 151372a-d. Comparisons.—The small size and flattened na- ture of the cones of this species separate it from the 816 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY other Permian species which are larger and generally deeper. Fully grown cups of this species attain only about half the length of T. boesei or T. conida. Discussion.—This species has somewhat different ecology from that of other Permian species, which are commonly bioherm dwellers. Teguliferina parva occurs commonly in small spreading clusters on a limy mud base. The clusters have little depth and are usually only one cup deep. Specimens are com- monly found in small patches which could not have had much effect on the bottom. Other genera of brachiopods are rarely associated with the clusters. Teguliferina solidispinosa, new species Plate 207: ficures 19-27 Fairly large for genus, robust and thick-shelled; width greater than length; cups irregular, with ragged dorsal side; aperture elliptical, wider than long, narrowly reflected lip. Attachment surface large; hood long and flattened. Anchor spines thick, long, and with abundant webs and attach- ment sheets. Apertural spines thick, crowded, often united distally, laterally attaching to inner wall of posterior side to form excurrent channel. Brachial valve thin and delicate, with strong me- dian ridge and large elevated cardinal process. Measurements (in mm).—From locality USNM 701c, specimens 154100a (holotype) and b, respec- tively: length 18.0, 13.1; brachial valve length 17.0?, (?); surface length 15.0?. 19.0; hinge width 3.3, (?); height 15.0, 15.0; thickness 7.0?, (?). Stratigraphic Occurrence.—Neal Ranch For- mation. Locality.—USNM 701c. Diagnosis.—Thick-shelled Teguliferina with spines covering aperture. Types.—Holotype: USNM 154100a. Figured paratypes: USNM 154100a, c. Measured paratype: USNM 154100b. Comparison.—This species differs from others in the almost complete covering of the apertural spines over the cup and the fusing of their ends distally and laterally with the walls of the cup. Discussion.—This species is strongly reminiscent of Taphrosestria, new genus, in the construction of the spines and the channel they form for excurrent stream. The species does not have the regular de- velopment of residual apertural flanges (cone-in- cone) seen in Teguliferina (Stehli). The web development is so strong on and between the spines that specimen 154100b shows sheets covering the host. In specimen 154100a the early rhizoid spines are very slender but are preserved behind a sheet or wall formed by the welding of the spines together by attachment shell. Genus Acritosia Cooper and Grant, 1969 Acritosia Cooper and Grant, 1969:5. Small to moderately large variable cones having protective spines on anterior side only; cones oblique in youth but even and nearly circular in adults. Margin of cup with slight flare. Brachial valve oblique within cup; vestibule deep. Exterior with strong concentric wrinkles; rhizoid spines stout, circular in cross section. Pedicle valve interior with strong aulacoterma; apex only slightly thickened; pseudodeltidial re- gion short and confined to apical region, not mi- grating dorsally. Muscle region not strongly thickened. Brachial valve flat to slightly concave, with mod- erately long neck. Cardinal process like that of Teguliferina, erect, shaft short; muscle region slightly thickened, scars separated by low double ridge. Endospines few, strong. Type-Species.—Acritosia magna Cooper and Grant, (1969:6, pi. 5: figs. 17, 18). Diagnosis.—Teguliferinidae with rhizoid spines having circular cross section and without strength- ening webs. Comparison.—This genus is intermediate be- tween Teguliferina and Cyclacantharia. It is distin- guished from Teguliferina by its round anchor spines, whereas the other genus has flat, weblike attachment spines. Acritosia is unlike Hercosia in lacking the strong apical septum of that genus, but it may be confused with Cyclacantharia, which likewise does not have a median septum. Cyclacantharia, however, differs from Acritosia in having a complete circle of protective spines around the inner margin of the aperture and is provided with a prominent muscle mound at the apex of the pedicle valve. Furthermore, the pedicle valve of Acritosia does not migrate dorsally as the shell advances in age, a feature linking it with the Teguliferinidae. NUMBER 19 817 Discussion.—As presently constituted this genus includes species that are strongly contrasting in their appearance. The type species is large, thin- shelled, and variable; A. peculiaris, new species, is strongly flattened; A. solida and A. vestibula, both new, are thick-shelled; and A. teguliferoides (R. E. King) is small, stout, and oblique. In spite of these marked differences they have many char- acters in common. All are strongly oblique in youth and have the brachial valve apically hinged as in Teguliferina. With growth, this valve main- tains its apical position or migrates very slightly. It never migrates to the extent seen in Cyclacan- tharia, Hercosia, or other Richthofeniacea. Acritosia magna Cooper and Grant Plate 199: figures 1-29 Acritosia magna Cooper and Grant, 1969:6, pi. 5: figs. 17, 18. Large, thin-shelled cones varying from high to somewhat spreading; anterior side flattened; pos- terior side broadly rounded. Apex small, bluntly pointed, directed posteriorly; attachment surface small. Young forming wide, spreading, oblique cones. Surface wrinkled and with concentric lines of growth. Rhizoid spines round and slender. Pedicle valve with numerous short, stout spines on inside margin of anterior side; aulacoterma well marked and extending obliquely around in- side of cup, lying just posterior to the protective spines on anterior side. Muscle field not thickened, but with low median myophragm. Interarea small; posterolateral flattened areas small or nearly obsolete. Brachial valve nearly flat; transversely pear- shaped, sides extended and narrowly rounded; an- terior margin gently rounded to nearly straight. Posterior extension short. Brachial valve interior with narrow and erect cardinal process; buttress ridge low or nonexistent. Breviseptum low and obscure. Adductor scars slightly thickened, elongate. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 701h 151737a 24.5 ? 33.0 5.0 27.9 24.0 151737b 26.2 16.4 33.0 4.3 26.3 18.6 151737c 32.3 18.7 43.0? 4.2 33.0 27.4 2.7 151737d 28.7 ? 31.0 ? 28.5 22.0 151737e 31.4 ? 42.0 ? 27.0 37.3 151737£ 20.9 ? 31.0 ? 22.3 22.6 USNM 701k 151739a 23.0 15.0? 31.0 4.0 25.2 18.0 151739b 24.0 ? 43.0 ? 24.8 25.4 151739c 20.6 ? 40.0 ? 27.4 25.6? 9.0 151739d 17.8 12.4? 24.0 5.0 28.6 14.4 6.1 151739e 20.7 ? 30.0 ? 36.4 14.3 ? USNM 701g 151735a 18.0 ? 28.0? ? 28.2 22.0 ? (holotype) Stratigraphic Occurrence.—Neal Ranch For- mation (beds 9-14). Localities.-----USNM 701c, 70lg, 701h, 701k. Diagnosis.—Wide, thin-shelled Acritosia with flaring cups. Types.—Holotype: USNM 151735a. Figured paratypes: USNM 151734; 151737e; 151738; 151739b, e, f, h; 154043a, b; 154044a, b, d. Mea- sured paratypes; USNM 151737a-f, 151739a-e. Un- figured paratypes: USNM 151737a-d, f; 154044c, e. Comparison.—The large size and thin shell dis- tinguish this species from all others of the genus. The species can be confused only with A. pecu- liaris, new species, which is similar in size but has a thicker shell, stouter protective spines, and less flared aperture. Discussion.—This is the largest of the Tegulifer- inidae occuring in the Wolfcampian (Neal Ranch Formation). It occurs intimately intergrown in large "colonies" of Teguliferina boesei R. E. King. 818 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Acritosia magnifica, new species Plate 308: figures 24-27 Large, bluntly conical, starting as squat, spread- ing cup, attaining maximum width early and then growing vertically; apical angle near or above 100°, length and width nearly equal; sides strongly wrinkled but with only small cone-in-cone effect. Surface strongly wrinkled; rhizoid spines scattered over entire cup, very thin. Protective spines only on anterior side of cup. Apex small with very small cicatrix. Brachial valve deeply inset, not granu- löse, with strongly and narrowly convex shoulders. Sides narrowly rounded, anterior margin broadly rounded. Interior of pedicle valve with small aulacoterma; floor with somewhat thickened muscle region. De- tails of brachial valve not preserved. Measurements (in mm).—From locality USNM 724j, specimens 154055a and b (holotype), respec- tively: length 25.5, 26.4; brachial valve length (?), 18.0; width 32.3, 31.4; thickness 20.6, 13.4; height 35.4, 23.2; aperture width 27.5, 26.3; aperture length 18.4, 24.4. Stratigraphic Occurrence.—Road Canyon For- mation. Locality.—USNM 724j. Diagnosis.—The largest species of Acritosia, with rapidly expanding cup in the young but long and cylindrical in the adult. Types.—Holotype: USNM 154055b. Figured paratype: USNM 154055a. Discussion.—This is an unusual species for its shape, size, and combination of characters. The cup starts off initially as a low, squat cone which expands rapidly reaching its maximum width at an early age, e.g., in specimen 154055a, at about one- third the height of the cup. The anchor spines are very slender and delicate for such a large shell. The brachial valve has strongly rounded shoulders that fit into the reentrant formed by the flat areas, large in this species, bounding the hinge. These specimens are referred to Acritosia be- cause their protective spines are located on the ventral side only and there is no strong median septum as in Hercosia. A fair-sized muscle mound can be seen in a crack in the holotype and is sug- gestive of a trend toward Cyclacantharia. Another feature linking it to Acritosia is the small develop- ment of cystose shell located mainly in the apical part of the cone. Acritosia peculiaris, new species Plate 201: figures 1-45 Large cones, variable, oblique to erect, with wide apical angle and large, somewhat flared aperture. Brachial valve strongly oblique within cup, thus de- fining shallow vestibule. Hood long, flat to con- cave. Cross section broadly to somewhat narrowly elliptical. Sides rounded, but anterior and posterior slightly to strongly flattened. Protective spines stout, short, anastomosing. Surface concentrically wrinkled; rhizoid spines slender. Apex not strongly thickened by cystose shell. Brachial valve flattened posteriorly, concave an- teriorly with short, narrow, neck and sloping shoulders. Sides rounded to subtruncate; anterior margin nearly straight. Surface coarsely papillose to spinose in young, strongly and thickly papillose in adults. Pedicle valve interior with strong and oblique aulacoterma located just under spine row on an- terior side; muscle mound low, with diductor scars clearly defined on each side. Posterolateral areas not strongly developed. Brachial valve interior with large and erect car- dinal process buttressed posteriorly by lophidium; lateral ridges moderately well developed; median buttress ridge strong, continuous with breviseptum. Endospines stout, few in number, forming one or two rows. Measurements (in mm).— -Acritosia peculiaris, new species: brachial brachial apical valve valve surface hinge mid- aperture aperture angle length length width length width width height thickness length width USNM 707g 151776a 43° 20.0 15.0? 24.0 46.0 6.0? 32.2 30.3 ? 20.0 31.5 151776b 60° 25.1 18.0 23.5 45.0 6.0 28.7 17.6 ? 24.0 99.0 USNM 707ha 151756a (holotype) 51° 21.4 18.5 22.0 33.0 6.2 26.5 33.0 20.0? 16.6 29.7 151756b 42°? 22.4 20.0 22.5 37.0 5.3 25.5 25.0 13.5 23.6 26.9 NUMBER 19 819 Stratigraphic Occurrence.—Lenox Hills For- mation, Bone Spring Formation, Skinner Ranch Formation (Dugout Mountain, Decie Ranch, Pop- lar Tank and Sullivan Peak members), Hess Formation. Localities.—Lenox Hills: USNM 705m. Bone Spring: USNM 725c, Dugout Mountain: USNM 733-1. Decie Ranch: USNM 707a, 707g, 708q, 714t, 716p, 720f, 720g, 727u. Poplar Tank: USNM 707h, 707ha, 708e, 710x. Sullivan Peak: USNM 707d, 707x, 710d, 714y, 715j, 722h, 722-1, 727a, 733j, 739g. Skinner Ranch: AMNH 504, 520; USNM 705n, 715n, 723s. Skinner Ranch (low): USNM 71 Id, 712p, Skinner Ranch (top): USNM 705r, 71 Or, 722m, 723-1, 726h, Hess: USNM 702d, 716o, 716n, 726n. Diagnosis.—Large Acritosia with anteriorly con- cave brachial valve, poorly developed posterolat- eral areas and large, erect cardinal process. Types.—Holotype: USNM 151756a. Figured paratypes: USNM 151756b; 151776a, b; 154045a-h; 154046a, b, d; 154047; 154048. Measured para- types: USNM 151756b; 151776a, b. Unfigured para- types: USNM 154046c. Comparison.—Of all species of Acritosia this one may be compared to A. magna Cooper and Grant, which it approaches or equals in size. The differences between the two are discussed under A. magna. Discussion.—The shortness of the body chamber helps to identify this species in unsilicified speci- mens or those in matrix. Large specimens from the Decie Ranch Member are placed here although it has not been possible to see details of the interior. Acritosia silícica, new species Plate 200: ficures 1-29; Plate 309: figures 1-5 Average size for genus, forming oblique cones approximating angle of 90° in adults; sides fairly straight; apex bluntly pointed; aperture roundly elliptical, margins strongly flaring in many speci- mens. Anterior side of aperture with moderately long, rather delicate, pointed spines. Surface ru- gose, undulations interrupted and irregular. Rhi- zoid spines numerous, rounded in section but thin and delicate. Pedicle valve with irregular lateral profile, um- bonal region usually flattened, median region narrowly rounded and anterior slope long, flat- tened or gently convex. Posterior side short and flattened; hinge sockets wide and deep. Aulaco- terma well-defined. Muscle region medially thick- ened. Brachial valve flat to gently concave, usually somewhat geniculated anteriorly toward dorsal di- rection. Hinge very narrow, forming moderately long neck; anterior and anterolateral margins de- flected. Brachial valve interior with long, slender, narrowly compressed cardinal process; long shaft marked by median groove extending anteriorly into median ridge thus forming two parallel ele- vated lines extending nearly to mid-valve; endo- spines long and delicate. Measurements (in mm).— Acritosia silícica, new species: brachial brachial apical valve valve surface hinge mid- aperture aperture angle length length width length width width height thickness length width USNM 725b 152687a 61° 9.4 12 8.8 18.0 ? 12.4 10.0 5.8 7.7 9.7 152687b 70° 13.5 ? ? 18.5 4.2 17.2 9.3 ? 6.5 8.7 152687c (holotype) 88° 15.0 9.7 11.3 22.0 2.4 17.6 7.9 3.6 9.4 13.0 152687d 91° 15.3 ? ? 17.0? 4.0 19.7 10.7 ? 11.5 13.7 152687e 91° 15.0 ? ? 24.5 3.7 17.9 8.4 ? 9.6 14.1 152687f 70° 10.5 ? ? 14.5 2.7 12.8 6.9 ? 7.0 9.6 152687g 80° 14.3 10.6 13.2 21.5 3.6 19.0 10.0 4.3 8.8 12.4 152687h 70° 17.7 10.2? 13.2 28.0 ? 20.6 12.4 6.0 9.1 13.0 Stratigraphic Occurrence.—Hueco Fomation (upper), Cibolo Formation. Localities.—Hueco: AMNH 700; USNM 725b. Cibolo: AMNH 703. Diagnosis.—Medium-sized Acritosia forming round oblique cones with moderately deep vesti- bule and moderately flaring apertural margins. Types.—Holotype: USNM 152687c. Figured paratypes: USNM 152687a, b, d, g, h, o, q, s-v, x. Measured paratypes; USNM 152687a, b, d-h. Un- 820 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY figured paratypes: USNM 152687e, f, i-n, p, r, w. Comparison.—This species suggests Teguliferina boesei R. E. King, but that species has webbed rhizoid spines. It is most like A. teguliferoides (R. E. King) but that species is more oblique, usually smaller and has a thick mat of rhizoid spines as anchors. It is much smaller and more oblique than A. magna Cooper and Grant, or A. peculiaris and solida, new species. Discussion.—This species is abundant in a small patch at USNM 725b. It evidently lived in intimate masses because specimens of all sizes and shapes were recovered from the residues. Many young speci- mens show the initial form to have been circular but unfavorable position caused many of them to be elongated on further growth. The hinge sock- ets of the pedicle valve in the young have a strong anterior marginal rim. Acritosia solida, new species Plate 202: figures 43-61 Fairly large, thick-shelled cones rounded on an- terior side but flattened to concave on posterior side, apex twisted strongly toward posterior, small point of attachment. Hood in adults usually strongly concave. Aperture usually strongly flat- tened on anterior side. Surface strongly wrinkled, with cone-in-cone effect marginally. Rhizoid spines generally rounded and slender. Pedicle valve with deep vestibule; aulacoterma strong; posterolateral areas poorly developed; mus- cle field not strongly thickened. Interior spines num- erous and long. Protective spines thick. Brachial valve widely pyriform with narrowly rounded sides and broadly rounded anterior margin. Profile nearly flat. Cardinal process large, erect, buttressed by double median ridge. Lateral ridges strong; adductor scars elongate. Endospines few and large. Measurements (in mm).—Brachial valve length and thickness unmeasurable. surface hinge mid- length length width width height USNM 702d 151741a 14.0 30.0 4.3 23.6 16.8 151741b 18.0 29.0 5.0 22.4 16.4 151741c 14.0 23.0 ? 13.7 18.0 151741d 18.4 27.0 ? 28.0 20.2 151740b 18.2 34.0 ? 28.2 22.5 (holotype) Stratigraphic Occurrence.—Skinner Ranch For- mation (Dugout Mountain Member), Hess Forma- tion (Taylor Ranch Member). Localities.—Skinner Ranch: USNM 727f. Dug- out Mountain: USNM 732e. Taylor Ranch: USNM 702d, 716n, 716o. Diagnosis.—Thick-shelled and large Acritosia with strongly concave posterior side. Types.—Holotype: USNM 151740b. Figured par- atypes: USNM 151740a; 151741a-c, e, g. Measured paratypes: USNM 15174la-d. Unfigured paratypes: USNM 151740a; 151741d, f. Comparison.—This is a stout-shelled species of moderate size strongly resembling Hercosia uddeni (Böse) It differs from that species in not having a median septum, in having much stouter and fewer protective spines, and in a nearly apical bra- chial valve articulation. This species is much larger than A. teguliferoides (R. E. King) and also A. vestibula, new species. The latter has rounder and more compact cups than A. vestibula, whereas A. teguliferoides is oblique and strongly reminiscent of Teguliferina. Acritosia teguliferoides (R. E. King) Plate 200: ficures 30-34; Plate 202: figures 1-42; Plate 203: figures 1-3, 26-40; Plate 284: figures 34, 35 Prorichthofenia teguliferoides R. E. King, 1931:99, pi. 30; figs. 2-7. Teguliferina? teguliferoides (R. E. King) Stehli, 1954:330, pi. 24: figs. 5-8. Small, oblique, thick-shelled cones cemented by small, bluntly pointed apex which is directed pos- teriorly; aperture flattened on posterior side but well rounded on opposite side. Hood flattened to concave. Anchor spines slender, round and num- erous. Pedicle valve interior with numerous protective spines on inside of anterior margin; aulacoterma strong; posterolateral areas concave and prominent; muscle impressions not strong; myophragm weak. Brachial valve pyriform in outline, flat to concave in profile. Side narrowly rounded and anterior broadly rounded; posterior moderately extended and narrow. Brachial valve interior with elevated cardinal process buttressed by low median ridge continuous with breviseptum. Lateral ridges strong. NUMBER 19 821 Measurements (in mm brachial surface width length valve length length hinge midwidth height thickness AMNH 625 151752a 13.2 9.7 23.0 ? 16.9 12.6 7.0 151752b 11.8 9.8 18.0 ? 15.7 11.0 6.2 AMNH 628 151753a 12.9 10.3 21.0 4.1 17.5 11.6 7.5 151753b 14.7 ? 26.0 ? 19.5 13.8 ? 151753c 12.4 11.0 21.5 3.2 15.7 8.4 6.1 151753d 9.6 8.0 17.0? 2.4 11.4 7.2 5.9 Stratigraphic Occurrence.—Bone Spring For- mation (lower), Skinner Ranch Formation (Decie Ranch Member), Cibolo Formation. Localities.—Bone Spring: AMNH 625, 628, 629, 631, 660; USNM 728e, 728f, 728h. Decie Ranch: USNM 707a, 707w, 708q. Skinner Ranch (base): AMNH 520; USNM 705a, 705o, 709u, 71 li, 71 lp, 715v, 720e. Cibolo: 728-1, 738f, 738r. Diagnosis.—Small, stout, thick-shelled Acritosia with a thick brush of attachment spines on all sides of the pedicle valve. Types.—Lectotype: YPM 11957a. Figured para- type: YPM 11952, 11957b, T11064. Figured hypo- types: AMNH 27312/1-3 and USNM 153674; 154049a-d, f, h, i, k; 154050a-f; 154052a, b, d, e; 154058a-i, 1, m. Measured hypotypes: USNM 151752a, b; 151753a-d. Comparison.—This is a small and strongly obli- que Acritosia, having about the same size as A.? vestibula, new species. It appears to be more oblique and to have a narrower and more pointed apex than that of A. vestibula, which is fairly well-rounded apically. It also possesses a heavier mat of anchor spines than the Road Canyon species. Discussion.—King failed to designate a type for his species and Stehli (1954) also did not select a type from King's lot. We therefore select a speci- men illustrated by R. E. King (1931, pi. 30: figs. 3a-b) from the Sierra Diablo (R. E. King 479) as lectotype. This specimen shows the strongly oblique form and has a remnant of the brachial valve preserved. It also has a trace of the spines on the anterior margin of the cup. Acritosia? vestibula, new species Plate 294: figures 1-16; Plate 308: figures 1-5 Small variable cones with wide aperture but usually with posterior side flattened or concave; vestibule deep; hood usually low and depressed anteriorly. Anterior marginal wall of cup with row of long delicate spines at high angle to axis. Apex bluntly pointed, straight, small, commonly incurved. Aperture not flaring. Surface with concentric wrin- kles, cone-in-cone feature not developed. Rhizoid spines delicate. Pedicle valve interior with aulacoterma well de- veloped, located well down in vestibule below spine row. Posterolateral areas large, flattened. Pseudodeltidial area short, open to interior. Muscle region not thickened; muscles commonly inserted in deep apical pit. Interior spines present. Brachial valve flat to slightly concave; not pa- pillose externally in adults. Neck short, not deeply excavated; shoulders nearly straight; sides narrowly rounded, anterior margin nearly straight to gently rounded. Brachial valve interior with delicate cardinal pro- cess covered by chilidium; median ridge obscure; adductor scars not thickened. Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USNM 702c, 709c, 71 Ou, 724a, 724d. Types.—Holotype: USNM 151743b. Figured paratypes: USNM 151742a, b; 151743a, b, f, h-j. Measured paratypes: USNM 151743a, c-i. Unfig- ured paratypes: USNM 151743c-e, g. Diagnosis.—This species is distinguished by its deep vestibule, delicate spines, and flat or concave posterior side. Discussion.—This is a rare species and not en- tirely characteristic of the genus. It is placed ten- tatively in Acritosia because it lacks the strong med- ian septum of Hercosia. It is not so oblique as nor- mal in Acritosia and the brachial valve is not obliquely placed. It cannot be assigned to Cyclacan- 822 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brachial brachial apical valve valve surface hinge mid- aperture aperture angle length length width length width width height thickness length width USNM 702c 151743a 58° 13.3 10.0? 11.5 22.0 4.0 14.9 13.6 6.0 12.0 16.2 151743b (holotype) 37° 13.8 10.0? 11.0 23.0 4.5 15.0 17.5 10.8 8.8 15.0 151743c 56° 11.3 8.8 10.5 19.0 3.8 13.4 9.7 6.9 12.2 14.4 151743d 44° 13.2 10.0 12.0 21.0 3.8 15.0 15.0 10.7 12.2 14.0 151743e 46° 13.7 9.0 11.0 20.0 3.3 14.0 13.0 7.3 9.5 15.0 151743f 34° 13.5 10.0 11.5 23.0 3.8 15.0 16.0 9.2 14.0 16.0 151743g 54° 12.0 9.0 11.0 23.0 2.8 14.5 14.6 8.3 12.3 14.7 151743h 54° 11.4 9.5 10.0 19.0 2.5 13.0 10.0 7.5 11.0 12.0 151743Í 54o? 7.8 7.0 6.5 1.5 2.0 7.7 5.5 3.9 9.3 8.7 tharia because it does not develop spines around the whole inside of the aperture. attached productidinids. We therefore eliminate this family from the Aulostegacea. Superfamily AULOSTEGACEA Muir-Wood and Cooper, 1960 [Ex Aulostegidae Muir-Wood and Cooper, 1960] Productida derived out of Stropholosiacea by re- duction and elimination of teeth and sockets, modi- fication of the pseudodeltidium, and elimination of the chilidium but retaining the ventral interarea. Usually attached initially but may live free if broken from mooring. This superfamily is established for the large num- ber of genera having the palintrope well defined, the interarea with the delthyrium open or closed by an elytridium, and a lophidium. In the young stages these brachiopods are attached by beak ce- mentation, buttressed by rhizoid spines. Many lived attached throughout their lives but others lived free on the sea bottom after having been ripped from their moorings. Families represented in the Glass Mountains are: Cooperinidae, Aulostegidae, Spyridiophoridae, Tschernyschewiidae, and Scacchinellidae. In the Treatise on Invertebrate Paleontology (part H, 1965:H460) the family Chonetellidae is classified among the Strophalosiacea and is placed between the Spyridiophoridae and the Tscherny- schewiidae. This is certainly a poor placement be- cause that genus has no strophalosiid characters. Moreover it was not an attached form and must have lived like the marginiferids or other small un- Family COOPERINIDAE Pajaud, 1968 [Ex Cooperininae Pajaud, 1968] Small to minute, cemented by large cicatrix and anchored by rhizoid spines; brachial valve with prominent erect trilobed cardinal process. Pedicle valve with platelike palintrope having smooth in- terarea. No elytridium. Brachial ridges present. Genera in West Texas: Cooperina Termier, Ter- mier, and Pajaud, 1966; and Atelestegastus, new genus. The first genus is very common in the Willis Ranch Member of the Word Formation, but is less common elsewhere. It appears to have originated in the Pennsylvanian because several specimens were taken in the Pawnee Formation (Labirdie Member) from Nowata County, Oklahoma. These belong to "Leptalosia" spondyliformis (White and St. John) as figured by Dunbar and Condra (1932). The brachial valves of the Oklahoma specimens have the same adductor platforms as the Permian species. In the Permian it occurs in Wolfcampian sediments as well as in the higher formations. Atelestegastus also may occur in the Pennsylvanian as indicated by externally similar specimens from the Pawnee Formation in Oklahoma. We do not agree with the opinion of the Ter- miers and Pajaud that Cooperina belongs in the Thecideidina. This little genus has all of the dis- tinguishing characters of the Productidina as ex- NUMBER 19 823 plained by Cooper and Grant (1969:17) and elab- orated below. Genus Cooperina Termier, Termier, and Pajaud, 1966 Cooperina Termier, Termier, and Pajaud, 1966:332-335.— Cooper and Grant, 1969:17. Small, attached by umbonal part of pedicle valve; subrectangular in outline; hinge equal to or less than midwidth; pedicle valve surface spinose but not costellate; rhizoid spines confined to ears and umbo; ornament spines long and slender, curving over anterior margin; brachial valve surface with scattered spines. Pedicle valve strongly convex and deep; palin- trope thin and flat, without delthyrium; interarea flat; teeth absent; anterior half marked in older specimens by low, thick median ridge extending nearly to midvalve. Brachial valve flat to gently concave, smooth or with fine spines in well-preserved specimens; car- dinal process large, laterally expanded, bilobed to quadrilobed, lobes widely divergent; visceral region enclosed by elevated, submarginal rim diverging from base of cardinal process and united anteriorly to form median ridge extending to midvalve; med- ian ridge grooved anteriorly; adductors attached to thin elevated platforms attached partly to valve floor and partly to lateral submarginal ridge; bra- chial ridges indistinct, elongated. Type-Species.—Cooperina inexpectata Termier, Termier, and Pajaud (1966: 332-335). Comparisons.—Cooperina is characterized by its attached habit, spinose pedicle valve and spiny bra- chial valve, lack of teeth in the pedicle valve or sockets in the opposite valve, the flangelike submar- ginal ridge, short but prominent median ridge, and the elevated, excavate adductor platforms. Absence of teeth and sockets indicates relation- ship of Cooperina to the Aulostegacea but the ad- ductor platforms and lateral flanges as well as the peculiar median ridge set it apart from all mem- bers of that family. The interior of the brachial valve has some features that are prophetic of the Thecideidae, although probably not ancestral. Discussion.—Although many hundreds of speci- mens of this genus were examined, it was not pos- sible to determine some features in detail. It was not possible to make out clearly the form of the ventral muscle scars. The presence of a short obscure median ridge indicates the presence of the adductors in the umbonal cavity but not one specimen re- vealed their form. The diductor scars are equally obscure but faint markings on both sides of the posterior half of the interior indicate these muscles to have been large and strong, as usual in the Pro- ductidina. Some pedicle valves show minute serrations or a row of small ridges along the inner margins oppo- site the ears. These suggest some of the strainer de- vices observed in other productids. The median ridge in the anterior half of C. inexpectata is com- monly strongly developed and undoubtedly is the counterpart to the deep groove that occurs in the median ridge of the brachial valve. These two ridges divide the anterior of this species into two halves. The same is probably true of the two other known species, but in C. parva the median ridge is not developed and the partition of the valves is accomplished by the median ridge of the brachial valve. Some features of the brachial valve are variable, such as the cardinal process, the development of the median ridge, and the adductor platforms. The cardinal process varies from small, narrow, and bilobed to laterally expanded, especially at the base, and with a large quadrilobed myophore. This structure is considerably compressed dorsoven- trally and is set slightly obliquely to the plane of valve junction to accommodate insertion of it under the thin, flat palintrope. On the posterior face the cardinal process is like that of other aulo- stegaceans in having the lateral lobes grooved. On the opposite side or ventral face the lobes are sepa- rated by a shallow depression that extends nearly to midvalve, or at least to the adductor platforms. In some specimens the two lobes are separated dis- tally by a small, occasionally deep notch which emphasizes the bilobation. In such cases each lobe is divided by the median groove mentioned above, with the result that the cardinal process appears to be quadrilobed. In many specimens the base of the cardinal pro- 824 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY cess is widely expanded laterally, giving the struc- ture the appearance of a single large plate. The cardinal process is unlike the characteristic aulo- stegacean process in lacking the alveolus and in not having a lophidium. The lack of an elytridium is undoubtedly the reason for these absences. The submarginal ridge of the brachial valve is one of its most important characteristics. This is usually strongly elevated on the sides but is low where it loops anteriorly and changes direction to produce the median ridge. The median portion of this ridge is most elevated and forms a flange fitting closely to the inner walls of the pedicle valve. The anterior looped portion of this ridge is com- monly serrated and may thus have acted as a siev- ing device in feeding. The median ridge, like most of the other charac- ters of this interesting little genus, is variable. After the lateral submarginal ridge or flange turns med- ially at the anterior it extends posteromedially to unite near midvalve. This forms a knife-edge sep- tum facing posteriorly, but the anteromedian face is a triangular groove, narrowing posteriorly, which accommodates the median ridge of the opposite valve in species which possess it. Perhaps the most diagnostic character of this genus is the adductor platforms in the brachial valve. These make two small, elevated flat plates deeply excavated dorsally and with free edges fac- ing ventrally and medially. These little plates range in position from horizontal to nearly verti- cal, viewed with the brachial valve lying on its dor- sal or outer surface. This change in position is determined by the exterior curvature of the bra- chial valve. Cooperina, according to evidence found in this study, is always attached by the pedicle umbonal region, usually by a generous portion of it. The normal position of the animal is for the adult to have the plane of its commissure at about right angles to the surface of an attachment. The authors of Cooperina (Termier, Termier, and Pajaud, 1966: 332) regarded this little genus as the forerunner of the Thecideidina, which appear in the succeeding Triassic Period. The interior of the brachial valve, with its thick and elevated med- ian ridge bisecting the shell, is obviously like that of some of the Thecideidina, especially Davidson- ella Munier-Chalmas. In our opinion, the pro- ductid characters of this genus militate against its inclusion in the Thecideidina. These characters were outlined by us (Cooper and Grant, 1969:17) as follows: 1, presence of spines on both valves; 2, straight hinge without teeth and sockets; 3, prob- able pseudopunctate shell; 4, lobate cardinal process of productid type; 5, productid type of brachial ridges in the brachial valve; 6, flabellate diductors in the pedicle valve; and 7, manner of attachment to the substrate. The productids in their evolution gradually elim- inated the pseudodeltidium. It is present in Strophalosiacea but was eliminated from this super- family to produce the Aulostegacea. A pseudodel- tidium is rarely present in the Productacea (Pro- ductellidae) and it was eliminated from all of the later genera. No pseudodeltidium is present in Cooperina, but the pseudodeltidium is one of the most important characters of the Thecideidina. To produce a thecideid from Cooperina would require the redevelopment of teeth and sockets and acquisi- tion of punctae while at the same time eliminating pseudopunctae (taleolae). Other genera of the Cooperinidae, described by Grant (1972), exhibit forms of ptycholophous bra- chidia that resemble some of the Mesozoic thecidea- ceans and suggest that the general form of the productidine lophophore was ptycholophous. Der- ivation of the thecideans from some stock within the productidina remains a possibility, although the necessary changes in shell structure are great. Cooperina inexpectata Termier, Termier, and Pajaud Plate 210: figures 1-61; Plate 212: figures 11-22 Cooperina inexpectata Termier, Termier, and Pajaud, 1966: 332.—Cooper and Grant, 1969:17. Small, attached, squarish to longitudinally rec- tangular; sides subparallel to moderately divergent; anterior margin narrowly rounded; anterior com- missure with slight fold toward brachial valve; pedi- cle valve strongly but unevenly convex, umbonal region flattened but anterior half subgeniculate; brachial valve flat to concave. Surface of pedicle NUMBER 19 825 valve spinöse, that of brachial valve with small spines in well-preserved specimens. Pedicle valve with broad area of attachment ap- proximating posterior half; anterior half moder- ately to strongly convex. Surface spinose, spines rhizoid and ornamental. Rhizoid spines long, slen- der, forming fringe around area of attachment and tufts on ears; ornament spines long and slen- der, attaining length of at least 4 mm and crudely arranged in concentric rows. Interarea moderately long, measuring 0.75 mm on shell 4mm long, fiat, with anterior margin straight and extending to lateral margins to form line of contact for brachial valve. Ears small, flattened, approximately forming right angle. Umbonal cavity moderately deep, roofed by flat and delicate palintrope. Pedicle valve interior with obscure muscle area, diductor scars appearing to occupy most of posterior half; adductors not clearly discernible but located on low short elevation in adults and old specimens; anterior half divided by low median ridge, also best defined in young or old specimens. Brachial valve gently convex to moderately swol- len in posterior half to one-third but moderately to strongly concave in anterior one-half to two- thirds. Hinge straight, articulating with or abutting straight edge of palintrope. Brachial valve interior with elevated submar- ginal ridge running from each side of base of cardinal process along margins to curve narrowly at anterior and unite medially, forming elevated ridge that extends to about midvalve; submar- ginal ridge elevated, forming prominent wall later- ally that fits into thickened lateral margins of ped- icle valve. Cardinal process oblique to commissure and protruding markedly toward ventral valve, there inserted into umbonal cavity; cardinal pro- cess bilobed to trilobed, lobes moderately diver- gent, each lobe in old specimens also bilobed to form quadrilobed process. Base of cardinal process expanded laterally in dorsal view; grooved medially in ventral view. Ears prominent, flattened and de- pressed dorsally to submarginal ridge. Median ridge forming high crest almost dividing valves into two chambers, knife-edge sharp on posterodorsal edge but grooved along anterior face, groove receiving elevated ridge of pedicle valve. Adductor scars at- tached to two elevated platforms, or shelves, lo- cated at angle between lateral submarginal ridge and valve floor, attachment being made on floor and to ridge; adductor platforms ranging from par- allel to nearly perpendicular to valve floor, depend- ing on curvature of shell. Well-defined productid brachial ridges in well-preserved specimens. Measurements (in mm).— brach- ial valve maximum hinge thick length length width width ness SNM 706e 152637a 2.2 2 2.0 1.3 1.0 152637b 2.8 1.9 2.8 1.9 0.9 152637c 3.0 2.4 2.8 1.9 1.5 152637d 3.3 2.5 2.8 1.8 1.3 152637e 3.3 ? 3.2 2.6 2.1 152637f 3.7 2.7 3.6 2.7 2.1 152637g 4.2 3.G 3.0 2.6 1.9 152637h 4.0 ? 3.5 2.9 1.7 152637Í 4.5 ? 4.2 3.0 2.3 Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Member), Word Formation (China Tank, Willis Ranch, Appel Ranch mem- bers and lenses between last two), Bell Canyon For- mation (Hegler Member). Localities.—Getaway: AMNH 512, 600; USNM 728, 732. Word: USNM 732s, 737w, 741p. China Tank: USNM 706c, 706z, 726r, 733q. Willis Ranch: AMNH 505, 506; USNM 706, 706e, 723t, 723w, 724u, 735c. Appel Ranch: USNM 719z, 722t. Lenses: USNM 706b, 742b. Hegler: AMNH 635; USNM 731, 732a. Diagnosis.—Rectangular to square Cooperina having long curved ornament spines, a broad attach- ment area on the pedicle valve and strongly ele- vated median ridge in the brachial valve. Types.—Figured hypotypes: USNM 152637d, g; 153184; 153185a, b; 153198a-n, p; 154142a, b, e, f, h; 154l43a-d. Measured hypotypes: USNM 152637a-i. Discussion.—As in all attached forms, the an- atomical features of C. inexpectaia are highly variable. Such shells are so dependent on the object to which they are affixed that their shape and size are usually greatly influenced. The attachment sur- face of C. inexpectaia is large and attachment is commonly reinforced by a dense fringe of rhizoid spines. The young are usually biconvex or convexi- concave, depending on the surface attachment. At 826 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY this stage the plane of valve junction is parallel to the surface of attachment but as growth continues the anterior margin and the commissure gradually change direction, until in the adult, they are ap- proximately at right angles to the attachment sur- face. During the time of the shifting of the angle of the commissure to the attachment surface, orna ment spines appear at the margin of the growing shell. Cooperina inexpectata did not have any favorite object to which it attached but used any dead shell in a sheltered position to which its larva could attach. Specimens have been seen on bryozoans, corals, pelecypods, and a great variety of dead brachiopods. The best preserved specimens are those that lodged in the living chamber of dead Cyclacantharia. These commonly preserve the long curved halteroid spines in best condition and com- pleteness. Cooperina parva, new species Plate 208: figures 13-38 Shell small, quadrate in outline, length and width about equal; sides gently rounded; anterior margin broadly rounded; hinge width slightly less than mid- width; anterior commissure without trace of fold- ing; cicatrix of attachment large, occupying about one-third valve length; spines on pedicle valve long and slender, exact length not known, distant and scattered on surface; rhizoid spines not crowded around cicatrix. Pedicle valve strongly convex, greatest convexity at midvalve; anterior profile broadly domed; in- terarea equal to about one-fifth valve length; sides thickened; ears not prominent, forming obtuse angle. Interior not showing form of muscle scars or any evidence of median septum at valve anterior. Brachial valve of unequal convexity, posterior half gently swollen, anterior half gently concave but with anterior margin gently reflected dorsally; sides elevated into moderately high flange descend- ing anteriorly, scarcely developed along anterior margin; anterior median ridge low and short, indistinctly defined to about midvalve; cardinal process erect, moderately stout, myophore with four small lobes. Adductor platforms elevated, slightly oblique to median line, nearly vertical, with free margins serrated. Measurements (in mm). brach- ial maxi- valve hinge mum thick- length length width width ness USNM 702c 152638a 2.3 1.5 1.4 2.4 1.2 (holotype) 152638b ? 1.4 1.1 1.7 0.4 152638c ? 1.2 1.2 1.8 0.2 USNM 702d 152639d 1.5 1.4 1.2? 2.0 0.3 152638e 2.0 1.5 1.8 2.3 1-2 152639f 2.0 ? 1.5 1.9 0.9 152639g ? 1.4 1.0 1.5 0.3? Stratigraphic Occurrence.—Hess Formation (Taylor Ranch Member), Cathedral Mountain Formation (Wedin Member), Road Canyon For- mation. Localities.—Taylor Ranch: USNM 702d. Cathe- dral Mountain: USNM 702, 703a1, 72lu, 723u. Wedin: USNM 700x, 723v. Road Canyon: USNM 702c. Diagnosis.—Cooperina with a squarish outline, scattered spines, and poor development of the med- ian ridge in the brachial valve. Types.—Holotype: USNM 152638a. Figured paratypes: USNM 154174; 154175a; 152638b, c; 152639d-g. Measured paratypes: USNM 152638b, c; 152639d-g. Comparison.—The squarish outline of this species distinguishes it from the somewhat triangu- lar outlines of C. triangulata and C. subcuneata, both new. It is smaller than C. inexpectata and has fewer and more scattered ornament spines irregu- larly arranged, and it has a much less prominent median ridge in the brachial valve. Cooperina subcuneata, new species Plate 209: figures 38-59 Small, but about medium size for genus; outline rudely triangular with anterior wider than posterior which is considerably narrowed in most specimens. Sides rounded and converging posteriorly; an- terior margin narrowly rounded. Hinge narrow, interarea moderately long, triangular, flat, and without delthyrial opening. Beak slightly incurved. Cicatrix moderately large, varying from a third to NUMBER 19 827 more than half posterior surface of pedicle valve. Anchor spines delicate, forming fringe adjacent to cicatrix. Pedicle valve most convex anterior to cicatrix, there swollen and narrowly rounded. All slopes steep. Cardinal extremities slightly to moderately acute; interior with low median ridge. Brachial valve exterior flatly concave, umbonal region slightly swollen. Surface marked by several rows of small holes. Interior of brachial valve with thin, fairly large posterior adductor platforms. Me- dian ridge long, high, narrowly expanded anteriorly. Cardinal process, moderately long, bilobed. Measurements (in mm).— brach- ial maxi- valve mum hinge thick- length length width width ness height USNM 726d 152641a 3.0 2.8 2.5 1.9 1.2 1.4 USNM 721j 151241a 3.5 2.7 2.7 1.7 1.4 1.5 (holotype) 151241b 3.4 2.9 2.7 1.3 1.0 1.2 Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—AMNH 501; USNM 702c, 71 Ou, 716xa, 720d, 721j, 721s, 721t, 721x, 721z, 722e, 722v, 724c, 726d, 726e, 732j, 736x. Diagnosis.—Small subcuneate Cooperina with rows of pits on the brachial valve. Types.—Holotype: USNM 151241a. Figured par- atypes: USNM 151241b, c; 152641a; 154140; 154141. Measured paratypes: USNM 152641a, 151241b. Comparison.—This species is larger than C. parva, new species, and less triangular and larger than C. triangulata, new species of the Neal Ranch Formation. It is most like C. inexpectata Termier, Termier, and Pajaud, but has a narrower hinge region, thinner and less robust valves, a narrower anterior expansion of the median ridge of the brachial valve, and numerous tiny pits on the ex- terior of the brachial valve. Discussion.—This species is generally rare, and it is difficult to find the small brachial valves in the mass of fine debris in the abundant detrital mate- rials of interbiohermal accumulations. The speci- mens found in living position usually have their commissure at a low angle to the attachment sur- face, but some are found at a fairly high angle but seldom at 90°. The most unusual feature of this species is the presence of numerous pits, arranged crudely in concentric rows on the exterior of the brachial valve. These do not seem to accord with spines of the opposite valve. They may be sites of small spines but no trace of spines was seen on any specimens, not even the best preserved ones. Cooperina triangulata, new species Plate 209: figures 1-37 Minute, triangular in outline. Hinge very nar- row; greatest shell width at anterior; lateral margins widely divergent anteriorly, indented just anterior to cardinal extremities, somewhat narrowly rounded anterolaterally; anterior margin with strong median reentrant; anterior commissure slightly folded to- ward brachial valve; pedicle valve deep, brachial valve nearly flat to moderately concave; rhizoid spines fine, on ears and body of shell; no ornament spines observed. Brachial valve with scattered dim- ples corresponding to rhizoid spines. Pedicle valve strongly convex in lateral profile, narrowly domed in anterior profile; umbonal region narrow; umbonal and lateral slopes precipitate; an- terior slope steep. Ears proportionately large flat- tened and protruding laterally beyond lateral mar- gins. Interarea small, triangular, short, with median thin, translucent part over cardinal process and in position of delthyrium. Pedicle valve interior with slight thickening of floor of umbonal chamber but no median ridge or septum visible; anterior half with poorly defined median elevation. Brachial valve in lateral profile with umbonal region gently convex to flat but anterior two-thirds broadly to moderately concave; anterior margins deflected somewhat dorsally; ears prominent, pro- truding laterally, approximately at right angle. Cardinal process nearly erect, quadrilobate when viewed from ventral side, bilobed to trilobed in dorsal view. Flanges along concave sides thin and strongly elevated, fitting closely inside steep sides of pedicle valve; adductor platforms small, narrow, steeply tilted. Median elevation in median half steep and high, lateral ridges forming it not meeting to make median ridge or septum, but remaining separated by deep groove of varying width. 828 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brach- ial maxi- valve hinge mum thick- length length width width ness heigf SNM 701d 152640a 2.6 1.7 1.0? 2.6 0.8 1.4 152640b 2.7 2.1 1.1 2.6 1.0 1.3 152640c 3.1 2.2 1.2? 2.6 1.5 1.7 (holotype) 152640d 3.2 2.6 1.4 2.7 1.6 1.8 Stratigraphic Occurrence.—Neal Ranch For- mation (bioherms in beds 9-14 of King's section and Cooper's beds 9-12). Localities.—USNM 701, 7013, 701d, 721g. Diagnosis.—Minute, triangular Cooperina hav- ing a lobate anterior margin, very narrow hinge and deeply grooved median ridge in the anterior half of the brachial valve interior. Types.—Holotype: USNM 152640c. Figured paratypes: USNM 154138a, b; 154139a, b; 154140d, g, e-i. Measured paratypes: USNM 152640a, b, d. Unfigured paratypes: USNM 154140a, b, f. Comparison.—This species may be distinguished from the others described herein (except C. subcu- neata, new species) by its triangular outline, lobate anterior, narrow hinge, and the deeply grooved me- dian elevation of the brachial-valve interior, which does not terminate in a median ridge. This latter character distinguishes it from C. subcuneata, which is also triangular in outline. Discussion.—This little species is fairly common near the middle of the Neal Ranch Formation at its type section. Features of importance that need further explanation are the spines and the brachial valve interior. Spines are well scattered over the surface of the pedicle valve but they consist only of rhizoid spines. They are seldom seen near the anterior margin in the few specimens attached in growth position. Most of the material available for study consists of specimens stripped of the spines. In most, the lo- cation of the spines is shown only by pits, and these do not reach the anterior margin. No ornament spines were observed on any specimens. The features of the brachial valve interior are fairly normal for the genus, except for the median ridge. The cardinal process appears to be of the same type and fairly strongly lobed in all specimens in which it is visible. The adductor platforms are elongate and narrow, compared to those of the other species, and are fairly widely separated. The great difference in this species, compared to the others, is in the course of the lateral flanges and submarginal ridge. The flanges are high and thin but descend in height where they approach the an- terolateral margins. Here they make a, narrow loop and extend posteriorly; however, they fail to unite to form a sharp median ridge or crest as in the other species. Variation.-—Considerable variation can be de- tected in the width of the hinge and the anterior. Both of these features are dependent on the object to which the shells are attached. Ecology.—The ecology of this little species is the same as that for the other members of the genus. It does not appear to have had a favorite surface for attachment but does favor crannies in dead shells. Remarks on Stratigraphy.—Residues from Pennsylvanian limestones have produced speci- mens having the form of C. triangulata but no in- teriors have been found to prove the true generic affinities of these specimens. Leptalosia spondyli- formis (White and St. John) from Pennsylvanian rocks of Iowa and Nebraska has the form of Coo- perina and its interior, as indicated by specimens from Nowata, Oklahoma, has the same adductor platforms. Cooperina species Five specimens from two localities represent a possible species of Cooperina. Two specimens from USNM 705a (USNM 151232) are nearly square in outline, the largest measuring about 2.6 mm in length and width. It is thick-shelled, with the in- terior sides narrowing toward the beak, indicating a narrowing of the brachial valve. The interarea is short and narrow. The brachial valve is fairly deeply concave and has a slight dorsad wave in the anterior margin. Three specimens from USNM 728f (USNM 151247) are thick shelled and some- what narrow at the hinge, suggesting probable identity with specimens from USNM 705a. Atelestegastus, new genus [Greek atele (imperfect) + stegastos (cover)] Small, attached by ventral umbo and anchored by rhizoid spines; subcircular in outline; concavo- NUMBER 19 829 convex in profile; anterior commissure unfolded; pedicle valve marked by scattered rhizoid and or- nament spines; brachial valve with fine erect spines. Outer margin of pedicle valve broadly flattened. Pedicle valve with palintrope and flat interarea; teeth absent; floor of umbonal chamber somewhat thickened, but adductor and diductor impressions not clearly visible. Brachial valve with large bilobed cardinal pro- cess, each lobe divisible into two parts; shaft stout, extending anterior to posterior margin; median septum indistinct, extending anterior to midvalve; adductor impressions small; brachial ridges large, extending anteriorly from lateral margins of ad- ductor scars and occupying most of anterior half; brachial ridges marked by row of endospines anteriorly. Type-Species.—Atelestegastus marginatus, new species. Diagnosis.—Attached aulostegaceans having broad outer rim in pedicle valve and brachial valve with reduced median septum and large bra- chial ridges. Comparison.—This interesting genus of small at- tached brachiopods suggests Cooperina at first glance, but differs in the broad, flattened rim of the pedicle valve, absence of a prominent median sep- tum or ridge, absence of adductor platforms, and the great development of the brachial ridges. Absence of teeth excludes it from the Stropha- losiidae. The form of the brachial valve separates this genus from any of the small aulostegids, such as Xenosteges. Discussion.—The most remarkable anatomical feature of this little brachiopod is the disparity in length between the pedicle and brachial valves. The brachial valve forms a lid over only a part of the pedicle valve. The outer rim of the latter is quite uncovered and suggests a trend toward the richthofeniids or teguliferinids. However, the inter- area is well developed and the general morphol- ogy, except for the rim, is that of the Auloste- gacea. Atelestegastus contrasts quite strongly to Coo- perina in the interior details of the brachial valve. In the latter the important features are the me- dian ridge or ridges and the adductor platforms. In Atelestegastus, externally like Cooperina, these two characters are completely lacking. Like other attached forms Atelestegastus exhibits a variety of distortions because of accidents of its situation. It apparently prefers the interior parts of dead shells where it must have been somewhat sheltered but specimens occur in which it is perched in what must have been an exposed situa- tion. Atelestegastus marginatus, new species Plate 211: figures 1-51 Small, subcircular, lateral and anterior margins well rounded; posterior margin umbonate, small to moderately large cicatrix of attachment; hinge straight and narrower than greatest width at mid- valve; lateral and anterior margins of pedicle valve flattened, deflected, forming rim to receive against inner edge of brachial valve, pedicle valve thus forming a miniature cup. Rhizoid spines scattered with moderate density over whole surface of pedicle valve, numerous on ears and posterior margin; rhizoid spines long or short depending on surface of attachment. Ornament spines apparently few but scattered among rhizoid spines, full length not determined. Brachial valve with scattered, erect, fine, hairlike spines, true length also not known. Pedicle valve strongly convex in lateral profile, broadly convex in anterior profile; greatest depth slightly posterior to midvalve; umbonal region swollen; all slopes steep, but anterior slope less so than lateral slopes, flattened or depressed by shal- low sulcus; ears prominent, rounded on ventral side but flattened and conspicuous on dorsal side, usu- ally forming rounded, obtuse angle. Palintrope thin, delicate, interarea flat with delthyrium visible be- cause of extreme thinness of covering plate or when plate is broken out. Flattening of ears continued anteriorly around inner shell margin to define or surround restricted body cavity. Pedicle valve interior with muscle scars and other details obscured or not sufficiently impressed to be visible. Brachial valve unequal in profile, umbonal re- gion slightly to moderately swollen, but anterior two-thirds moderately to deeply concave; anterior margin reflected dorsally to fit against inner mar- gin of rim of pedicle valve; ears prominent, flat- tened; cardinal process long-shafted, stout with lateral strengthening along posterior margin; me- 830 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY dian septum much reduced; brachial ridges large, descending from sides of adductor patches directly anteriorly to make loop near anterior margin, there extending posteriorly to end near midvalve; outer margin of brachial loops low ridge laterally but marked by small endospines anteriorly. Cardinal process with prominent myophore lobes. Measurements (in mm).— brach- ial maxi- valve mum hinge thick- length length width width ness height USNM 701d 150877a 3.8 ? 4.1 2.9 ? 1.8 150877b 3.7 2-5 4.0 2.3? 0.9 2.2 150877c 3.3 2.4 3.6 2.3 0.8 1.4 150877d 3.6 2.1 3.5 2.7 1.1 1.8 150877e 3.1 2.1 3.2 2.5? 0.8 1.6 USNM 721g 154135c 4.7 4.2 5.0 2.3 1.3 2.3 (holotype) Stratigraphic Occurrence.—Neal Ranch For- mation (beds 9-14 of P. B. King). Localities.—USNM 701, 701a3, 701c, 701d, 701h, 701k, 721g, 727e. Diagnosis.—Subricular Atelestegastus with broad anterior rim on pedicle valve. Types.—Holotype: USNM 154135c. Figured paratypes: USNM 150875; 150877b, f-1; 150878a, b; 154135a, b; 154136; 154137a, b. Measured para- types: USNM 150877a-e. Unfigured paratypes: USNM 150877a, c-e. Family AULOSTEGIDAE Muir-Wood and Cooper, 1960 Interarea in pedicle valve only; delthyrium usu- ally closed by elytridium and/or lophidium. Bra- chial valve interior with trilobate or quadrate cardinal process with antron in young stages; brachial ridges given off horizontally. Subfamilies: Echinosteginae Muir-Wood and Cooper, 1960; Chonosteginae Muir-Wood and Cooper, 1960; and Institellinae Muir-Wood and Cooper, 1960. Subfamily ECHINOSTEGINAE Muir-Wood and Cooper, 1960 Aulostegidae with spinose pedicle valve capillate, lamellate, or costellate in some genera; brachial valve without spines, surface dimpled, costellate or capillate; brachial valve adductor scars on plat- forms. Genera in West Texas: Echinosteges Muir-Wood and Cooper, 1960; Edriosteges Muir-Wood and Cooper, 1960; Limbella Stehli, 1954; Xenosteges Muir-Wood and Cooper, 1960; and Cactosteges, new genus. Echinosteges is generally characteristic of the Word Formation but occurs rarely in the Road Canyon and Bell Canyon formations. Edriosteges is confined to the Skinner Ranch, Cathedral Moun- tain, and Road Canyon formations. Limbella is commonest in the Neal Ranch Formation but ranges into the Skinner Ranch above and Gaptank below. Xenosteges appears first in the Lower Cathe- dral Mountain, is common in the Road Canyon, but less common in the Word Formation. It occurs in the Bell Canyon Formation but is rare. Genus Limbella Stehli, 1954 Limbella Stehli, 1954:329.—Muir-Wood and Cooper, 1960: 107.—Williams et al., 1965:H455. Moderately large, concavo-convex, attached by pedicle valve umbo and anchored by rhizoid spines on ears, posterior margin, and umbonal slope; an- terior commissure faintly and narrowly folded; sur- face of pedicle valve marked by moderately long scattered ornament spines and fine costellae; bra- chial valve costellate but without spines. Anterior and lateral margins with flattened ventrally di- rected frill on both valves. Pedicle valve usually with short and inconspicu- ous interarea; delthyrium open. Diductor scars flabellate, large; adductor field narrow and long, consisting of two elevated long slender inner scars and outside them a narrow dendritic but very ob- scure scar. Inner periphery thickened. Brachial valve with thick, commonly exaggerated, lateral ridges extending from base of cardinal pro- cess; cardinal process deeply excavated in young but usually without antron in adults; shaft short, myophore varying from bilobed to trilobed. Lophi- dium long and narrow. Adductor field narrowly elliptical, consisting of inner conspicuous set of muscles and outer pair, one on each side of inner ones. Inner pair lobate; thickened, outer pair ob- NUMBER 19 831 scure. Breviseptum thin, bladelike, commonly poorly developed (or poorly preserved). Brachial ridges obscure, slightly oblique. Anterior slope marked by thick but short endospines. Type-Species.—Aulosteges wolfcampensis R. E. King (1931:95, pi. 26: figs. 1-6). Diagnosis.—Aulostegidae with costellate exterior, short interareas, no elytridium, slightly thickened muscle scars in both valves; no subperipheral rim and a frill in all adult stages. Comparison.—Limbella is closest to Edriosteges and Strophalosiella. From the former it differs chiefly in several small details. On the exterior it is more strongly costellate than Edriosteges, which has been called capillate rather than costellate to distinguish the degree of development. Another feature of Limbella not shared by Edriosteges is the concentric lamellae remaining on the exter- ior by the continual abandonment of successive frills. The ornament spines of Limbella generally appear to be longer than those of Edriosteges es- pecially in the younger specimens. Inside the pedicle valve the elytridium is not de- veloped in Limbella and the palintrope is usually short. The muscle field is like that of Edriosteges, but only the inner pair of adductor scars is well developed, and these are not elevated to the degree degree usual in Edriosteges. The outer pair of ad- ductor scars, usually so prominent in Edriosteges, is usually difficult to see in Limbella and is never thickened as in that genus. The interior of Limbella is like that of Edrio- steges but differs in the development of the car- dinal process and other features. The cardinal process in immature Limbella is tentlike, but with growth the antron is usually effectively filled, and generally no trace of it is left in the adult forms. The paired points on the ventral face of the car- dinal process shaft, possible accessory muscle attach- ments in Edriosteges, are not developed in Limbella. The development of the lateral ridges of Limbella is in great contrast to their very modest develop- ment in Edriosteges. The latter genus in adult forms makes a thick subperipheral rim around the margin of the brachial valve, but such a rim is not developed in Limbella. Another minor difference between the two genera is the stout, long endo- spines on the anterior slope of the brachial valve interior in Limbella. From the above it seems that the two are clearly different genera but they are definitely closely re- lated, perhaps Edriosteges having descended from Limbella. Strophalosiella Licharew (1935) is another genus possibly closely related to Limbella which may, perhaps, preoccupy Stehli's genus. This point cannot be proved, however, until better specimens than that illustrated by Licharew are found and de- scribed. Slrophalosiella is recorded from the Upper Carboniferous but no features of its interior have yet been published. The chief distinction between it and Limbella is the stronger costellation of the Russian shell than any seen on Limbella. A trace of the musculature is visible in one of Licharew's figures, which indicates no thickening of the ad- ductor whatsoever, which is different from Limbella and Edriosteges. Although one must admit the pos- sibility of Limbella being a synonym of Stropha- losiella, the two should be maintained as separate genera until the interior details of Strophalosiella are made known. Discussion.—Inasmuch as details of the anatomy of Limbella differ from those of Edriosteges and other Aulostegidae, it is important to describe some of these with care. Perhaps the features, or rather lack thereof, of most importance on the ex- terior are the interarea and elytridium. In most specimens of Limbella the palintrope is short and the delthyrium open, the latter varying in width from specimen to specimen, but usually fairly narrow. A few specimens have the beak and umbo somewhat elongated, but in these the delthyrium is effectively plugged by the high, keeled lophidium. Still fewer specimens with elongated beaks have the beak curved so that it hangs over the interarea. In these a plate closes the posterior or apical end of the delthyrium. The plate, however, is concave and a feature of the interior. The posterior edge of the lophidium slides over the concave surface of this plate. It is essentially an elytridium in reverse. Another feature of the interior of the pedicle valve worthy of notice is the dendritic outer ele- ment of the adductor field. This is usually im- possible or difficult to see except in very old specimens, and may not be clear in them. The scar usually is not strongly dendritic and is not as many branched as the same scar of Edriosteges. The interior of the brachial valve of Limbella is quite distinctive. In very young forms the cardi- 832 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY nal process is like that of other Aulostegidae, in the form of a tent. Two thin, sloping plates unite posterodorsally to bound a triangular cavity. In Limbella, unlike Edriosteges and Echinosteges, the cavity in the cardinal process is filled at an early age. The filling is well advanced in specimens less than 10 mm long. In most adults the cavity is filled at or before young adulthood, but some individuals failed to fill the cavity even after attaining the length and width of an adult. The variation in attainment of adult characters of the cardinal process appears to be similar in most of the genera. Specimens of small size, which would be deemed young because they are small, may have adult in- terior characters. Others, however, seemingly adult by virtue of their large size, may still retain many features of immaturity. These phenomena are also to be seen in Limbella. The development of the cardinal process in Lim- bella is intimately linked with the development of the lateral ridges. This is a feature that constitutes an important difference between Edriosteges and Limbella. In the young the lateral ridges form on either side of the cardinal process; but as growth continues, the cavity in the cardinal process is filled from the anterior, and the proximal ends of the lateral ridges lap onto the sides of the car- dinal process. This gives the lateral ridges a distinct curve, concave posteriorly. In late adulthood the cardinal process shaft appears to arise from the shelflike lateral ridge. In this form, the posterior of Limbella is utterly unlike that of Edriosteges. The shaft of the cardinal process of Limbella is generally compressed and when viewed from the ventral side is divided medially by a groove. This creates a bilobed cardinal process in this view. Usually the median lobe of the myophore is deeply grooved, and this further enhances the appearance of bilobation. The myophore, however, when viewed from the posterior, is trilobed but it seldom attains the exaggerated lobation seen in Edriosteges. The development of the adductor scars, especially in L. wotfcampensis, is worthy of note. These have the same elements noted in Echinosteges and Edriosteges, i. e., an inner set and an outer one. As in the other two genera, the inner set of ad- ductors in Limbella consists of two bilobed scars, an elongate, narrowly tear-shaped inner scar and a shorter but similarly shaped scar slightly oblique and joined to the inner one at the narrow end. These bilobed scars are the most prominent ele- ment in the muscle field. As in the other genera mentioned, these are smooth, but are much more closely pressed together. Outside of this bilobed pair is an elongate, obscure muscle patch, in some speci- mens showing as a series of discontinuous small scars and in others a definitely dendritic pattern, but consisting of a few lobes only. In L. wolfcam- pensis the adductor field is not greatly thickened, except for the inner pair of lobate scars, but in L. victorioensis the adductor field may be as strongly thickened as in Edriosteges. Limbella costellata, new species Plate 216: figures 16-23 Approaching Limbella woljcampensis in size, length and width nearly equal; sides gently rounded; anterior margin rounded, with wide frill in one specimen. Hinge about equal to mid- width. Surface of both valves costellate, costellae moderately strong, about 11 per 5 mm near front margin. Pedicle valve moderately convex in lateral pro- file, but anterior slope steeper than umbonal slope; anterior profile moderately convex, somewhat flat- tened and slightly depressed by shallow, narrow sulcus. Beak small, umbonal region somewhat in- flated: median region swollen; sides steep. Sulcus originating near midvalve, narrow, shallow, and in- conspicuous. Ears flattened, approximately form- ing a right angle. Adductor field not strongly elevated. Rhizoid spines of small diameter. Brachial valve moderately concave, deepest in umbonal region; ears flattened and prominent, separated from main concavity of valve by steep- ening of lateral slope; anterior somewhat flattened but with only faint evidence of fold. Dimples round, distant, and deep. Measurements (in mm).— sur- maxi- face hinge mum thick- length length width width height ness USNM 700g 149086a 36.3 56.0 42.7 41.8 16.8 ? (holotype) 149086b 33.8 48.0 36.0 39.0+ 14.0 ? 149086c 31.7? 51.0+ ? 38.0 15.0? 11.9 USNM 702n 154202 37.3 65.0? 40.0 35.5 21.0 14.0 NUMBER 19 833 Stratigraphic Occurrence.—Gaptank Forma- tion (approximately bed 10 of P. B. King (1937: 81), see note under USNM 700g), Uddenites- bearing Shale Member. Localities.—Gaptank: USNM 700g, 705q. Ud- denites: USNM 702n, 713e. Diagnosis.—Somewhat circular Limbella with strong costellae and distant deep dimples on the brachial valve. Types.—Holotype: USNM 149086a. Figured paratypes: USNM 149086b, 154202. Measured para- types: USNM 149086b, c. Unfigured paratype: USNM 149086c. Comparison and Discussion.—The above de- scription is based on 15 specimens all broken from the rock. These are thus difficult to compare with the fine and complete silicified specimens from the Neal Ranch Formation. Most of the measurements fall within the limits listed for L. wolf camp en sis except for the length and width, which seem more nearly equal in the Gaptank species. The costel- lation appears to be somewhat finer and the dim- ples of the brachial valve deeper than in the Neal Ranch species. Some of these specimens (USNM 149086) of Limbella are especially important because they are the oldest ones known and occur in a position re- garded as well within the Pennsylvanian. It is in- teresting to record that they occur with the earliest representative and most primitive form of Scac- chinella. They, like the latter, are thus "heralds" of the Permian. Two specimens from the Ud- denites-bear'mg shale are referred to this species. Limbella limbata, new species Plate 217: figures 5-17; Plate 257: figures 1, 2; Plate 475: figures 7-10 Large for genus, subquadrate in outline, width slightly greater than length, sides gently rounded, anterior margin broadly rounded. Pedicle valve with numerous spines, small spine bases scattered over surface; brachial valve with fine, shallow fairly num- erous dimples; both valves with interrupted con- centric wrinkles, and fine costellae, about 12 in 5 mm, near front margin. Pedicle valve unevenly convex in lateral profile, maximum convexity in anterior third, anterior slope steep, posterior slope long and much less steep than anterior one; anterior profile flatly con- vex on top and with precipitous sides; top of profile indented by narrow, shallow sulcus. Beak small, umbo gently convex; umbonal region broadly flat- tened; region just anterior to midvalve swollen; sulcus originating near midvalve, deepening an- teriorly but only moderately deep at front of some specimens, scarcely visible and broad in others. Interarea short, nearly flat; muscle field with ad- ductors not strongly thickened. Broad anterior frill present in well-preserved specimens. Brachial valve gently concave, deepest in an- terolateral parts; umbo broad, shallow, depressed; median line of ventrally sulcate specimens ele- vated to form low fold varying from distinct to non- existent. Ears flattened, not strongly demarcated. Lateral ridges curved, strong, adductor field only moderately thickened even in large shells. Brachial valve interior with large cardinal pro- cess but nonthickened adductor field. Lateral ridges thick and solid. Measurements (in mm).— maxi- surface mum thick- frill length length width height ness length USNM 714t 149101a 31.6 56.0 39.7 16.6 13.8 ? 140101b 40.0 61.0 39.3 20.0 16.0 ? 149101c 31.9 50.0 38.3 12.6 ? ? 149101d 34.7 54.0 42.7 15.8 Î ? 149101e 31.0? 45.0? 33.5 16.0 ? 10.5 149101f 32.8 46.0 32.4 12.7 ? ? 149101g 28.2 36.0 35.0 7.8 ? ? USNM 722-1 154208a 30.0 44.0 38.7 15.5 ? 10.6 (holotype) 154208b 33.0 50.0 34.0 17.0 ? 10.0 154208c 34.0 ? 39.0 ? ? ? Stratigraphic Occurrence.—Cibolo Formation, Skinner Ranch Formation (Dugout Mountain, Decie Ranch, Poplar Tank, and Sullivan Peak members), Skinner Ranch (base or top). Localities.—Cibolo: USNM 738c, 738q. Dugout Mountain: USNM 732e. Decie Ranch: USNM 707a, 714t, 715a. Poplar Tank: USNM 707ha, 708e, 741k. Sullivan Peak: USNM 705o, 707, 707b, 707d, 707g, 707x, 709-1, 713m, 715u, 722k, 722-1, 727a, 733j, 739g. Skinner Ranch (base): USNM 705a, 705n, 707w, 708q, 711d, 712p, 715n, 716p, 739-1. Skinner Ranch (top): USNM 710r, 722m, 723-1, 723s, 727f, 729-1. Diagnosis.—Large Limbella with numerous 834 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY spines on pedicle valve and many somewhat crowded dimples on the brachial valve, strongly con- vex in lateral profile and with deep pedicle valve. Types.—Holotype: USNM 154208a. Figured paratypes: USNM 149075; 153922a, b; 154208b, c, e; 154111. Measured paratypes: USNM 149101a-g; 154208b, c. Unfigured paratypes: USNM 154208d. Comparison.—Most of the specimens of this species, except the types, are not silicified, making direct comparison with silicified specimens difficult. Nevertheless, the species is closest to L. wolfcam- pensis but is often larger and always deeper than the Neal Ranch species. In its often wide shells this species also suggests L. victorioensis Stehli but is deeper, and the frill is not so wide as in the Sierra Diablo species. The lateral profile of L. limbata is different from that of both L. victorioensis and wolf campensis. Limbella victorioensis Stehli Plate 215: figures 4-27; Plate 216: figures 1-10 Limbella victorioensis Stehli, 1954:329, pi. 23: figs. 8-12. This species is uncommon in the Sierra Diablo, and it is difficult to obtain good specimens. None was found with both valves articulated, suggesting a type of occurrence different from that of L. wolf- campensis (R. E. King) from the Glass Mountains where many specimens were taken with both valves in contact. The two species are quite different when numerous specimens can be compared. L. wolf- campensis, however, has occasional individuals that outstrip the Sierra Diablo species in size, but gen- erally the Sierra Diablo species appears to be larger and more robust. The interiors of the two species also are different. The musculature of L. wolfcampensis is much more lightly impressed inside the pedicle valve than the other species and the brachial valves of the Sierra Diablo species has a stronger development of the adductor callosities. Furthermore, the cardinal pro- cess of the latter is generally more robust, but it is difficult to make a comparison, except in a broad way. Limbella victorioensis shows retardation and acceleration of growth of these structures in the same manner as seen in Echinosteges. There is no reason to believe that L. victorioen- sis lived in a manner different from that of L. wolf- campensis, which has been found in its actual living position. Measurements (in mm).—From USNM 728f, specimens 152648a and b, respectively: length 28.0, 31.2; brachial valve length 27.5, 27.9; maxi- mum width 36.7, 26.8; hinge width 31.8, 31.3; height 16.7, 18.4; frill length 12.5, 13.2; surface length 45.0?, 50.0. Stratigraphic Occurrence.—Bone Spring For- mation. Localities.—AMNH 629; USNM 725c, 728e, 728f, 728h, 742, 746. Diagnosis.—Large, wide-frilled Limbella. Types.—Lectotype: AMNH 27310/1:1. Figured paratypes: AMNH 27310/1:2-4. Figured hypo- types: USNM 152648a-c, 154200a-i. Measured hypo- types: USNM 152648a, b. Discussion.—The fine costellae of L. victorioen- sis are difficult to see, perhaps because of preser- vation, but the few specimens revealing costellae show them to be very similar to those of L. wolf- campensis. Like those of the latter they are low and broad, rather crowded, and number about 14 in 5 mm at the front of a large brachial valve, slightly more than in L. wolfcampensis. The Sierra Diablo species is also marked by the same thin, wavy, con- centric lamellae that are abundant on the surface of L. wolfcampensis, but in most specimens they are not so abundant as in the Glass Mountains species. The frill of the Sierra Diablo species, when well-formed, appears to be wider than that of L. wolfcampensis but, again, this is a matter of a few specimens showing this condition. Anterior cos- tation appears to be more prevalent in the Sierra Diablo species, and with somewhat stronger costae. An interesting feature of the anterior frill is its costation which corresponds to the anterior row of spines, each spine above or resting in the space be- tween costae. Evidently the spines are responsible in part for the wrinkling of the frill. Limbella wolfcampensis (R. E. King) Plate 213: figures 1-29; Plate 214: figures 1-21; Plate 215: figures 1-3; Plate 216: figures 11-13, 15 Aulosteges wolfcampensis King, 1931:95, pi. 25: figs. 1-6.— Muir-Wood and Cooper, 1960:107, pi. 131: figs. 6-16. Medium size, thin, subrectangular in outline; widest at about midvalve; sides gently rounded; NUMBER 19 835 anterior margin broadly rounded. Hinge generally narrower than midwidth. Surface costellate, sub- costate, and spinose. Pedicle valve somewhat narrowly and evenly convex in lateral profile; moderately and broadly convex in anterior profile; beak small, incurved; umbo swollen, merging with greatly swollen median region; lateral and anterior slopes precipitate; sul- cus narrow, shallow, originating posterior to mid- valve and extending to anterior margin. Ornament spines distantly scattered, gently curved, moderately long (10 mm) and tapering gently. Rhizoid spines thickest and largest on ears, becoming more slender and smaller medially; rhizoid spines extending an- terolaterally onto posterior part of frill. Entire sur- face marked by fine broad radial costellae, 7 to 10 in 5 mm at front of pedicle valve of adults, radial costellae and obscure interrupted costae, the latter originating anterior to base of ornament spine. Frill extending obliquely ventrad, moderately long (15 mm). Pedicle valve interior with short, curved inter- area, delthyrium narrow, open; umbonal chamber filled by muscle field, diductor scars large and flabellate; adductor field long and slender, median scars strongly elevated, surface smooth but long, narrow, and bilobed. Inner lobe long, lateral lobe short. Outer adductor scars obscure, difficult to see, faintly dendritic. Lateral walls of umbonal chamber covered by mat of small endospines. Brachial valve interior with prominent, frequ- ently shelflike lateral ridges hanging over adductor field; lateral ridges uniting with thin, usually short ear baffle bounding inner part of ear; cardinal pro- cess shaft united with brachial ridges. Cardinal pro- cess of young, open, tentlike, thickening and filling with age; adult cardinal process usually narrow, ventrad face bilobed, but myophore trilobed. Ad- ductor field consisting of paired scars, each scar divisible into three scars. Inner pair of scars bilobed, smooth and strongly elevated; outer scars de- pressed, difficult to see and obscurely dendritic. Areas on each side of muscle field minutely endo- spinose. Brachial ridges faintly impressed, com- monly not seen, somewhat posteriorly located. Breviseptum varying from thin, threadlike ridge to thin, bladelike septum, highest at anterior extrem- ity and usually extending slightly anterior to mid- valve. Anterior slope marked by large, stout, conical endospines. Measurements (in mm).—All hypotypes. brachial valve surface hinge ¡ maximum length length length width width height thickness frill length USNM 701k 149052a 33.2 24.4 52.0 39.8 41.2 19.6 10.8 6.0 149052b 31.3 21.7 41.0 30.6 39.2 14.0 7.4 8.0 149052c 26.5 18.7 40.0 32.7 34.6 13.1 0.3 3.0 149052d 18.0 15.9 26.0 15.9 23.3 7.5 5.3 ? 149052e 9.0 8.5 13.5 9.1 10.8 4.8 2.8 ? 149052f 35.3 29.4 53.0? 44.0? 48.8 17.8? 10.0 6.0 USNM 701h 149049a 37.7 ? 56.0 39.0 47.3 + 18.5 ? 5.0 149049b 35.9 26.0 63.0 39.1 42.1 17.0 10.4 8.5 149049c 32.4 23.0 ? 36.5 40.6 15.5 11.1 4.5 149049d 29.4 21.6 44.0 30.0? 34.1 15.3 8.5 5.0 149049e 25.0 19.0 43.0 26.8 30.6 15.0 10.2 ? 149049f 19.3 18.6 25.0 15.5 18.8 7.0 3.1 ? 149049g 13.2 12.0 15.0 11.9 14.4 3.3 3.0 ? 149049h 10.1 7.8 11.5 5.9 8.6 3.3 2.4 ? 149049Í 5.6 5.2 7.0 5.6 6.9 2.7 1.9 ? USNM 701 149063 45.6 31.2 68.0 41.7? 59.0 23.0 15.0 11.0 USNM 701c 149053a 38.0 26.7 61.0 36.0 44.4 26.6 16.4 ? 149053b 37.4 28.9 62.0 41.7 44.3 20.2 11.8 6.0 836 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Stratigraphic Occurrence.—Gaptank Forma- tion (Uddenites-bearing Shale Member), Neal Ranch Formation, Lenox Hills Formation. Localities.—Uddenites: USNM 701v, 703x. Neal Ranch: USNM 701, 701a, 701a1, 701a3, 701c, 701d, 701g, 701h, 701k, 701-1, 706x, 727e, 742c. Lenox Hills: USNM 704q, 705, 705k, 705m, 705s, 706g, 707j, 707m, 707z, 709t, 710w, 713q, 715, 715b, 716r, 737u. Diagnosis.—Large, subquadrate Limbella with rough, irregularly scaly surface. Types.—Lectotype (herein designated): YPM 11847a. Figured paratypes: YPM 11839, 11847b, 11849. Figured hypotypes: USNM 124120a, c, d, g; 149049b, c; 149052d; 149053a; 149061a-j; 154201; 154203; 154204; 154205; 154206; 154207; 154199. Measured hypotypes: see list. Type-Specimens.—R. E. King's cotypes consist of four lots of specimens, three of them at Yale and one at Austin. Lot YPM 11849 consists of two speci- mens from locality 193 ( R. E. King 1931, pi. 26: fig. 1). The larger of the two specimens is decorticated, both sides have been broken and the hinge and most of the beak are buried. It is a pedicle valve only but shows the strong convexity and the shallow sulcus extending from the umbo to the anterior margin. The anterior margin is reflected fairly strongly in an anteroventral direction. The um- bonal and visceral regions are strongly wrinkled. The second specimen in this lot is a fragment only of a young individual showing the longitudinal median region with a moderately deep sulcus. YPM 11839 from locality 88S (R. E. King 1931, pi. 26: figs. 5a, b) is another fragmentary pedicle valve with lateral margins broken away and only part of the hinge preserved. Part of the exterior surface preserves strong costellae on the umbonal and visceral regions. The specimen is strongly con- vex and strongly geniculated (an angle of 83°). King's idea that this is a triangular species evi- dently was derived from these broken pedicle valves. YPM 11847 consists of two specimens, one (R. E. King 1931, pi. 26: fig. 2) showing the interior of the brachial valve and the other (R. E. King 1931, pi. 26: fig. 3) a partial interior and partial impres- sion of the exterior, the latter showing well the impressions of the costellae and fairly well the rec- tangular form, although the ears are broken off both sides. The specimen showing the interior has the cardinal process fairly well preserved, and the lateral ridges are strong. The muscle area is clear but the median septum shows as only a slight line. Not one of the Peabody specimens is complete, and the three lots are hardly adequate to define a species. The same is true of the Texas specimens. T10185 consists of two specimens from locality 93. One of these, a fragment of the brachial valve interior, shows the cardinal process and muscle scars. The other specimen in this lot is an exfoliated pedicle valve, larger and somewhat less strongly geniculated than the other pedicle valves of the cotype lots. Although none of these cotypes is suitable to characterize the species, a type must be selected from them if the species name is to survive. Inas- much as a genus has been based on this species, it seems reasonable to put the species on as sound a basis as possible. Two stratigraphic levels are re- presented by these cotypes. One specimen (YPM 11839) comes from the Uddenites-bearing Shale Member. This specimen, which preserves its shape and ornamentation better than any of the others, is eliminated from consideration because many of the fine silicified specimens illustrated herein come from approximately King's locality 93, the location for several other cotypes. Specimen lot YPM 11849 is also eliminated from consideration. This lot is from Dugout Mountain and comes from the Lenox Hills Formation, a level far above the bed nine (of P. B. King) of the Neal Ranch Formation from which the remainder of the cotypes are said to have come. Neither of the cotypes belonging to the Uni- versity of Texas shows the outline well, nor does the pedicle valve have the ornament well preserved. By elimination we are left with the two brachial valves of lot 11847, and of these the specimen marked 11847a is the better. We select it as the type of the species. The lectotype is an imperfect brachial valve but it shows well the curved, strong brachial ridges, the subdued adductor field, and the thick endospines on the anterior slope. These are all features of the brachial valves of silicified specimens from USNM 701c, which is approximately King's locality 93. The list furnished by R. E. King from "bed 9" at lo- cality 93 is, as King states, probably float from "The next few higher beds on the side of the arroyo northeast of Wolfcamp" (R. E. King 1931:134). The limbellas were probably derived from P. B. NUMBER 19 837 King bed 12 ( = Cooper bed 9), where the genus is abundant. Comparison.—Exterior and interior, details sep- arate Limbella victorioensis Stehli from L. wolf- campensis King. Fine details of the exterior of the Sierra Diablo shell are not well preserved, but Stehli gave the main difference between the two species to be the lesser development of the costellae in L. victorioensis than in the Glass Mountains species. Other exterior differences between the two species appear to be the more recumbent nature of the ornament spines of L. victorioensis, the more prominent pustules at the base of the spines, and the narrower, shorter costae anterior to the pustules. The brachial valve of the Sierra Diablo shell is flatter than that of L. wolf campensis. Inside the pedicle valve of L. victorioensis an oblique ridge is developed inside the ear, whereas in the Glass Mountains species the ear is flattened and partly overhangs the umbonal chamber. The ear of L. wolf campensis is more strongly developed than that of the other species. Inside the brachial valve of L. victorioensis the brachial ridges extend directly laterally and are not curved. Furthermore, the adductors muscles are attached to thick plat- forms, as in Edriosleges. The endospines of the Sierra Diablo shell are much thicker than those of L. wolfcampensis. Discussion.—The localities USNM 701c, 701h and 701k are all bioherms along the same strike but the specimens from each of these localities vary slightly. Those from the first place are more ro- bust than the others. The bioherms represent as- semblages that once lived together rather than being washed into an environment. The variations shown by these specimens probably resulted from crowding together or contending with other species for space. Specimens of Limbella, few in number, were found in the Uddenites-bearing Shale Member of the Gaptank Formation just under the thick lime- stone identified as lower "Wolfcamp" by P. B. King. These specimens are not silicified and are difficult to identify. Their characters however, suggest to us that they are the same species as L. wolfcampensis. A feature characteristic of this species worthy of mention is the concentric lamellae appearing on the venter and slopes. This consists of numerous and crowded layers of shell which represent remnants of the frills produced by contraction and advance of the mantle at various stages in the growth. Limbella species 1 Plate 216: figure 14 Small to medium for genus, length and width nearly equal; outline subquadrate; sides gently rounded, anterior margin rounded and medially indented. Interarea short, about orthocline. Surface marked by fine, low, broad, and crowded costellae. Ornament spines short, scattered. Rhizoid spines long and slender, bunched on ears. Pedicle valve unevenly convex in lateral pro- file, greatest convexity just anterior to midvalve, posterior slope flattened, anterior slope steep. An- terior profile a broad, flat-topped dome with slight median depression. Beak short; umbonal region usually somewhat swollen. Sulcus usually promi- nent, shallow and inconspicuous on posterior slope, fairly strong and moderately deep on anterior half. Flanks bounding sulcus moderately swollen. Brachial valve with maximum concavity in um- bonal region, median region marked by broad, low fold originating just posterior to midvalve and ex- tending to margin. Flanks moderately deep, an- terior margins strongly deflected. Interior not seen. Measurements (in mm): From locality USNM 713x, specimen 152647, and from 702f, 149070a, respectively: length 28.5, 28.2; brachial valve length (?), 23.6; maximum width 30.9, 30.8; hinge width 28.6*, 27.6; thickness (?), 7.3; height 10.7, 13.5. Stratigraphic Occurrence.—Hess Formation (Taylor Ranch Member), Skinner Ranch Forma- tion (top). Localities.—Hess: USNM 702d, 702e, 702f, 702m, 71 Sx, 716n, 716o. Skinner Ranch (top): 705r. Diagnosis.—Subquadrate Limbella with maxi- mum thickness and convexity anterior to midvalve and with a strong median sulcus. Type.—Figured specimen: USNM 152647. Discussion and Comparison.—This species is un- common and difficult to obtain in a satisfactory state for description. It is also difficult to prepare specimens because they occur in a very siliceous matrix and cannot be cleanly etched. Had good specimens been obtainable, we would have estab- lished it as a species. It is readily distinguishable from the other limbellas by its medium size, the strong sulcus, and the even, broad costellae. Some uncertainty exists in the generic designa- tion of this species because it has the appearance of 838 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Edriosteges and apparently occurs with a species of that genus. The usual fairly strong development of the costellae on the pedicle valve, a feature rare in Edriosteges, determined the assignment to Limbella. Some decorticated specimens of Limbella from the Skinner Ranch Formation have the general form and size of the Taylor Ranch speci- mens but it is not possible to be sure of that assign- ment. Genus Edriosteges Muir-Wood and Cooper, 1960 Edriosteges Muir-Wood and Cooper, 1960:103. Generally large, usually quadrate to subpen- tagonal, concavo-convex with slight and narrow dorsal fold in anterior commissure, pedicle valve with long rhizoid spines on ears, posterior margin, and posterolateral umbonal slopes; body of shell covered by distant, short, curved, recumbent orna- ment spines. Brachial valve with concentric wrinkles and fine radial capillae. Pedicle valve interior with large flabellate di- ductor scars, elongate and elevated adductor field occupied by anterior elongated scars and posterior shorter scars. Elytridium short and usually poorly developed. Brachial valve with cardinal process and lophi- dium as in Echinosteges; adductor scars strongly dendritic, not on elevated platforms; breviseptum small and low brachial ridges horizontal, promi- nent. Types-Species.—Edriosteges multispinosus Muir- Wood and Cooper (1960:104, pi. 17: figs. 1-10). D i a g N o s i s.—Concavo-convex, nontuberculate Echinosteginae having a capillate brachial valve, slight development of the elytridium and adductor scars only slightly elevated. Comparison.—In its general form and other exterior details Edriosteges most closely resembles Echinosteges and Limbella. The differences between these genera consist of numerous small but never- theless persistent and cumulative characters. Echi- nosteges differs from Edriosteges in exterior details in having both valves strongly tuberculate, in hav- ing a greater development of the palintrope of the pedicle valve, and a consequent greater develop- ment of the elytridium. The brachial valve of Echinosteges is usually more nearly flat or anteriorly gently concave rather than strongly concave as in Edriosteges. It is also faintly to moderately strongly capillate. Internally, the pedicle valves of the two genera are essentially the same but differences can be de- tected in the brachial valves. In Edriosteges the adductor muscle scars are not located on elevated and excavated platforms as they are in Echinosteges and the brachial ridges of Edriosteges are much more strongly developed than in the other genus. The cardinal processes of the two are essentially the same with the exception that the antron of Edriosteges tends to be more completely obliterated than in Echinosteges. This is hardly a generic char- acter but is worthy of note. The fairly strong capillation of both valves of Limbella and the longer, stronger, and more distant recumbent spines on the body of the pedicle valve distinguish this genus externally from both of the others. The palintrope of the pedicle valve of Limbella is shorter than that of the other two genera and the cardinal process and adductor field are also very different. Consequently, Limbella in reasonably well-preserved specimens is readily dis- tinguishable from Edriosteges and Echinosteges. Edriosteges beedei (R. E. King) Plate 218: ficures 12-20; Plate 223: figures 19-22 Aulosteges beedei King, 1931:92, pi. 25: figs. 12, 13 [not 14 = Echinosteges and not 15 = young of Echinosteges tubércu- lo tus]. Types consist of four specimens marked cotypes: YPM 11876a and 11876b, T10690, and T11045. The first is a flattish specimen with imperfect mar- gin, nearly square, length and width nearly 20 mm. The second is more elongated than the first and with much of the left side missing. The third has two valves, and the beak is longer and more attenuated than that of the Yale specimens. This type and the Yale specimens are from the Leonard Forma- tion (loc. 123), but the fourth, cotype T11045, is from the Word Formation and is clearly an interior of Echinosteges tuberculatus (King) and not re- lated to A. beedei. We select cotype YPM 11876a as type of the species. As thus restricted the name becomes useful for a flattish Edriosteges that occurs in the Cathedral Mountain Formation. The lectotype is obviously an immature specimen. An adult has the following characters: it is elongate, rectangular in outline, and with a moderately long frill restricted to the pedicle valve. The lateral profile is moderately con- vex but in anterior profile it is somewhat narrowly domed. The interarea is long and has a long nar- row elytridium. Ornament spines are fairly evenly but distantly scattered over the surface and, as shown by the lectotype, are short and stout. The NUMBER 19 839 brachial valve is broadly and moderately concave and has a large lophidium. Measurements (in mm).—From locality USNM 702, specimen 149120 (hypotype): length with frill 47.0, brachial valve length 32.0, width without frill 29.9, interarea length 10.0, height 13.2, thickness 8.0, length of frill 8.4. Stratigraphic Occurrence.—Cathedral Moun- tain Formation. Localities.—R. E. King 123, USNM 702. Diagnosis.—Elongate and somewhat flattened Edriosteges with scattered, short, stout ornament spines. Types.—Lectotype: YPM 11876a. Paratypes: YPM 11876b, T10690. Figured hypotypes: USNM 149119, 149120. Comparison and Discussion.—This species is a smaller and less robust form than E. multispinosus Muir-Wood and Cooper and has a shorter frill and narrower outline. One specimen (USNM 149119) illustrates a type of injury common in attached forms when one side impinges against a resistant object which prevents or distorts growth on one side. Edriosteges compactus, new species Plate 223: figures 1-16 Small for genus, subcircular to square in outline; sides nearly straight; anterior margin gently rounded; anterolateral extremities narrowly rounded. Shell thick. Hinge nearly as wide as maxi- mum width just anterior to midvalve. Ears nearly at right angles. Surface of pedicle valve concentri- cally wrinkled and with distant short spines (about 7 mm) with small, slightly swollen bases. Rhizoid spines on ears stout. Anterior marginal frill short. Pedicle valve moderately and evenly convex in lateral profile, maximum curvature at or slightly anterior to midvalve; anterior profile somewhat narrowly domed but depressed medially by shallow sulcus. Umbonal and median regions inflated, beak small and inconspicuous. Lateral and anterior slopes precipitous. Sulcus moderately wide and shallow, originating just posterior to midvalve and extending to anterior margin. Interarea usually short but variable; elytridium usually small. Brachial valve moderately concave, greatest con- cavity anterior to midvalve; posterior third nearly flat. Surface wrinkled and obscurely dimpled. Pedicle valve interior having greatly thickened adductor field with individual scars like those of E. multispinosus. Brachial valve interior with prom- inent lateral ridges and long plane area posterior to them. Subperipheral rim thick and well-developed. Adductor field enormously thickened but scars simi- lar to those of E. multispinosus. Cardinal process thick-shafted and elaborate but with antron not closed; ventral face of cardinal process usually bilobed, myophore bilobed or trilobed, commonly exaggerated. Brachial ridges rounded, usually fairly well impressed. Breviseptum variously developed. Measurements (in mm).— brachial valve surface hinge maximum frill length length length width width height thickness length USNM 72it 152651a 30.0 22.3 50.0 24.3 28.5 18.0 11.2 4.3 + (holotype) 152651b 28.6 23.2 44.0 23.0 31.4 12.4 8.5 ? 152651c 28.7 22.0 48.0 25.7 33.3 15.5 10.0 ? 15265Id 28.8 20.6 41.0 18.3 27.7 13.4 9.2 2.6 + 152651e 23.8 19.9 30.0 19.3 21.6 8.8 6.0 ? USNM 709c 149139e 31.0 21.4 45.0 23.6 32.8 17.6 11.5 7.5 149139Í 31.7 24.0 52.0 28.0 38.7 15.0 14.3 ? 149139g 26.0 20.4 36.0 20.0 23.7 10.4 6.4 ? 149139h 20.1 16.7 25.0 20.0 24.2 7.5 6.8 ? 149139Í 16.8 14.9 20.0 14.5 17.7 5.5 4.5 ? 149139J 12.3 ? 16.5 10.0 13.0 4.4 ? ? USNM 710u 149140a 31.1 25.1 48.0 24.0 31.0 15.8 10.0 ? 149140b 32.8 20.5 ? 28.7 35.0 17.5 ? ? 149140c ? 25.4 ? 22.0 27.0 ? ? ? 149140d ? 25.4 ? 24.6 25.7? ? ? ? 840 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USNM 709c, 710u, 716z, 721j, 721t, 721y, 722e, 722f, 723x, 724a, 724d, 726d, 726e, 726f. Diagnosis.—Small, quadrate, thick-shelled Edrio- steges with greatly exaggerated interior details. Types.—Holotype: USN M 152651a. Figured paratypes: USNM 149137e, 149140c, 152651c. Mea- sured paratypes: USNM 149139e-j, 149140a-d, 152651b-e. Unfigured paratypes: USNM 149137a-d; 149140a, b; 152651b, d. Comparison.—This species differs from E. beedei (R. E. King) in its smaller size and greater con- vexity. It differs from E. multispinosus Muir-Wood and Cooper in its smaller size and subcircular to nearly square outline, moderate concavity of the brachial valve, and the exaggerated details of the interior. Many specimens of E. multispinosus attain greatly thickened muscle fields and cardinal process but the degree of thickening attained by E. com- pactus is usually not reached by the other species at the same length as in the Road Canyon form. Another feature characteristic of E. compactus is the great thickening of the cardinal process, without, at the same time, obliterating the antron. In nearly all the specimens of the brachial valve in the collection the antron is open, usually to a considerable degree. Edriosteges multispinosus Muir-Wood and Cooper Plate 218: figures 1-11; Plate 219: ficures 1-27; Plate 220: figures 1-32; Plate 221: figures 1-23; Plate 222: figures 6-13; Plate 223: figures 17, 18 Aulosteges medlicottianus, R. E. King (not Waagen), 1931:93, pi. 26: figs. 8, 9. Edriosteges multispinosus Muir-Wood and Cooper, 1960:104, pi. 17: figs. 1-10. Variable, strongly concavo-convex, subcircular to subtriangular in outline; sides and anterior margin gently rounded. Hinge equal to or less than shell- width. Greatest width at or anterior to midvalve. Ears prominent, forming obtuse angles in pedicle valve. Pedicle valve strongly and fairly evenly convex in lateral profile; strongly domed in anterior profile but gently and narrowly sulcate medially. Umbonal region moderately to strongly convex; median region swollen; lateral and anterior slopes steep; umbonal slopes steep. Sulcus shallow, occupying the anterior two-thirds. Anterior margin in old shells recurved ventrad to form smooth, capillate, or irregularly wrinkled frill from 5 to 15 mm long. Pedicle valve surface spinose, body spines recum- bent, slender, curved ventrad, and ranging in length from few millimeters to more than 12 mm. Spine bases only slightly swollen. Rhizoid spines in most individuals confined to ears and posterior margins, densely matted, long and ramifying, rare on umbonal slopes but occasionally appearing on frill. Palintrope generally short and wide; delthy- rium narrow, usually occupied by short, irregular elytridium commonly poorly developed, but in some specimens flared and expanded anteriorly to form socket for lophidium. Ornament, besides spines, consisting of irregular, obscure, discontinu- ous costae and fine capillae covering entire exte- rior especially near anterior margin. Pedicle valve interior with deep umbonal chamber occupied by elongate and swollen adduc- tor field separating broadly flabellate diductor scars; adductor scars consisting of anterior pair, an inside elongate scar with one or two oblique lateral lobes on outside, and two strongly dendritic, elongate scars lying obliquely behind anterior pair. Brachial valve varying from fairly deeply concave in young adults to gently concave in old individuals; exterior marked by irregular concen- tric wrinkles especially near ears, entire surface covered by fine, usually somewhat obscure capillae. Interior with variable cardinal process varying from deeply excavate tentlike structure at right angles to valve surface to strongly tri- to quadrilo- bate and solid; myophore usually strongly trilobate. Adductor scars thickened but not forming elevated platform, interior pair lobate, consisting of long inner scar running length of field and shorter oblique anterolateral lobe; outer scar also elongate but lying obliquely outside inner scar and strongly dendritic; breviseptum reaching slightly anterior to midvalve, bladelike and most elevated anteriorly, extending posteriorly to about midway between adductor scars. Lateral ridge varying from absent to strong and extending laterally from base of cardinal process to ear, there in some old specimens, meeting moderately thick, subperipheral rim; anterior slope marked by fine, scattered endospines. Brachial ridges well developed only in old specimens. NUMBER 19 841 Measurements (in mm).— brachial valve surface hinge maximum frill length length length width width height thickness lengtl USNM 703a 123906a 46.1 35.3 73.0 43.8 44.7 22.0 14.8 ? (holotype) 123906b 36.0 30.0 57.0 41.0 43.7 22.0 13.5 8.5 149116a 52.2 ? 78.0 42.0 64.6 27.0 ? ? 149116b 40.5 32.8 58.0 38.7 45.5 20.6 13.2 ? 149116c 31.7 25.9 45.0 31.0 + 40.2 14.1 7.7 ? 149116d 30.2 25.8 41.0 25.4 33.4 11.6 8.0 ? 149116e 19.1 17.3 27.0 20.0 24.8 8.2 5.6 ? 149116f 12.5 10.5 14.0 11.0 12.8 3.7 1.8 ? 149116g 7.3 ? 8.0 8.0 9.3 2.0 ? ? 149116h 18.7 14.5 26.0 12.9 21.6 7.1 5.4 ? 149116Í 4.6 3.5? 5.0 4.0 5.6 1.6 1.2? ? USNM 702c 149122a 47.6 39.2 75.0 45.5 47.2 23.4 10.0? ? 149122b 41.6 28.4 58.0? 35.3 46.7 22.1 17.0 12.0 149122c 45.5 30.0* 66.0? 33.4 56.8 22.9 ? 10.0 149122d 46.7 24.3 56.0? 30.8 42.2 + 19.8 10.3 15.0 USNM 703a1 152650 51.8 39.7 68.0 42.7 52.6 20.0 13.3 ? USNM 703b 149117 25.0 20.5 34.0 29.2 31.2 10.0 5.9 ? Stratigraphic Occurrence.—Cathedral Moun- tain and Road Canyon formations. Localities.—Cathedral Mountain: AMNH 500; USNM 702, 702a, 702b, 702inst., 702 low, 702un, 703a1, 703b, 703bs, 708c, 71 lq, 714w, 721u, 723u, 726o, 726u, 726y, 732u. Road Canyon: AMNH 501, 503, 507; USNM 702c, 703a, 703c, 703d, 707e, 716x, 719x, 720d, 721j, 721o, 721r, 721s, 721w, 721x, 721y, 721z, 722v, 724b, 724c, 724j, 726d, 726z, 732m, 734j, 735b. Diagnosis.—Strongly convex Edriosteges usually subquadrate outline and scattered strong spines over the pedicle valve. Types.—Holotype: USNM 123906a. Figured par- atypes: USNM 123906b, c; 123907. Figured hypo- types: USNM 149115a-c; 149121; 149122d; 154183b, d, f, g, i-k, m, n, p-w; 151484a-h, 1, m, p, q; 154185a- f; 154187; 154188a, b; 154189a-c. Measured hypo- types: USNM 123906b, 149116a-i, 149117, 149122a- d, 152650. Discussion.—Like Echinosteges, Edriosteges is variable; the variations in the two genera are quite similar but some differences can be noted. It is therefore pertinent to discuss in some detail the anatomical features of E. multispinosus so they may be compare with those of Echinosteges, as detailed under that genus. Exterior.—In general the young are wider than long, nearly plano-convex and anchored in the usual fashion. Growth additions are greater ante- riorly than laterally, with the result that the depth of the pedicle valve increases. This makes for increasing height with growth and a strongly con- vex adult. Naturally some specimens reach maxi- mum convexity more quickly than others and a few remain only moderately convex throughout life. These modifications may be accounted for by the congeniality of living conditions in the particular site occupied by an individual. Attainment of old adult characters before maximum length is reached and retention of juvenile features after maximum length has been achieved can be observed in numerous specimens. In spite of this the charac- teristic form of the adult is strongly convex. The frill is variably developed, from absent to a length of 15 mm. This feature may appear in shells before attainment of maximum length for the species and is a good sign of maturity. The spines too, are not uniformly developed. In some speci- mens they are somewhat more crowded than in 842 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY others, and a few appear to have smaller spines over the entire shell, even though that particular individual has attained the maximum size for the species. The interarea is usually short for the species but some individuals that lived in conditions so crowded that the hinge could not develop normally, became narrow hinged and long beaked; with consequent extremely long interareas. Specimens with short interareas normally are not provided with well- developed elytridia. These seem to be normal for the species but some specimens, usually old ones, show elaborate development of the elytridium. In such cases the elytridium is anteriorly flared or even alate. Spines given off from the elytridium are present in a number of specimens. As in other members of the Aulosteginae the elytridium assisted in the articulation of the valves. Interior.—The development and variation in the structures of both valves are of considerable interest. In the pedicle valve the muscle fields is of special significance. Pedicle Valve.—The area occupied by the di- ductor scars is restricted posteriorly by deposition of adventitious material which forms a broad, smooth area, in marked contrast to the spreading dendritic patches of the posterior adductor scars. Consequently, the diductor scars are more rectan- gular than fan-shaped, as in some other productid genera. The adductor field is normally long and narrow but in some specimens it flares anteriorly. The adductor field is divisible readily into anterior and posterior pairs of scars. The anterior pair is fairly simple and consists of an elongated inner scar and a shorter outer one. In the form of these scars, no two specimens seem to be alike. In some the outer scars are separated from the inner one, but in others they may be joined to the inner scar. What is uniform, however, is the clear distinction between the anterior and posterior scars. The posterior pair of scars is elongate and varies in position from distinctly posterior, only over- lapping slightly posterolaterally, to definitely lateral and extending but a short distance posteriorly. The posterior scars are finely dendritic and thus form a strong contrast to the simpler pattern of the anterior scars. In some specimens the anterior pair divides the field from front almost to back, but the posterior scars usually unite be- hind the anterior ones. Although the details of both pairs of scars are extremely variable, the scars, nevertheless, have a sameness in their pattern. A similar situation exists with the adductor field of the brachial valve. Brachial Valve.—The pattern of scars in the adductor field of this valve is almost exactly like that of the pedicle valve. The field is divisible into an anterior and a posterolateral pair of scars but the latter does not unite behind the former. The anterior pair of scars, like those of the pedicle valve, consist each of two tear-shaped scars, a long inner one and a shorter outer one, the two commonly joined posteriorly at their narrow ends. Many speci- mens, however, show a separation between them. The inner scar usually extends posteriorly for the entire length of the adductor field and separates the anterior from the posterolateral scars. Lying obliquely outside the inner scars are the finely dendritic posterolateral adductors. The pattern of these scars is quite elongate and fairly strongly elevated in some specimens. The dentritic nature of the posterolateral scars is not clearly observable until the shell has attained a length of about 15 mm. The anterior pair retains its twofold character in the youngest specimens in which the scars are clearly visible (12 mm). Below this size, or in larger but less mature shells, the scars cannot be readily individualized and the anterior and poste- rior pairs appear to form a single elongate, tear- drop-shaped impression. In the oldest specimens the inner pair of scars, which is usually clearly separable from the posterolateral set in younger adults, tends to break into short patches separated by grooves. When this occurs the anterior pair loses its individuality. Cardinal Process.—This structure exhibits most of the changes observed in Echinosteges but in many specimens the antron is completely obliter- ated. Of considerable interest is the strong develop- ment in most adults of the small projections or lobes that appear on the shaft. These have been in- terpreted (Muir-Wood and Cooper, 1960) as diduc- tor muscle attachments but their small size in American genera make this idea uncertain. No clearly defined scars have been seen in Edriosteges. In very old specimens the cardinal process reaches an enormous size and bears no resemblance to the youthful hollow form. Trilobed and quadrilobed forms are fairly common, and the myophore migrates through a large angle to face in a posterodorsad direction. NUMBER 19 843 A feature of the brachial valve interior charac- teristic of Edriosteges, but not developed in Echinosteges, is the peripheral rim. Prematurely adult forms exhibit this feature but generally it is well developed only in mature or gerontic adults. It takes the form of a ridge originating on the ears, and in some specimens continuous with the lateral ridge, which „extends anteriorly and surrounds the interior and locates on the edge of the anterior slope. In some specimens it is moderately strongly elevated especially just anterior to the ears. This ridge appears to be a response to deepening of the pedicle valve in growth. Ecology.—No details observed in the ecology and life habits of this species are significantly differ- ent from those of other similarly attached forms. Remarks on Stratigraphy.—This species is common at USNM 702c, where specimens are exceptionally well preserved. At this place the species does not attain as large a size as the largest specimens from USNM 703a. The species occurs at two distinct levels, one is at the top of the section, where a series of bioherms directly underlies the thin, carbonaceous limestone of the Road Canyon Formation. The other occurs far below this level where bioherms with abundant Leptodus also con- tain Edriosteges that differ somewhat from the younger specimens. Many of the specimens collected at this lower level are slightly less convex than the specimens from the Road Canyon. Mixed with these, however, are specimens having the normal characteristics of the species. Unfortunately, the collection is not large enough to determine whether or not a new species is present. The same remarks will hold for specimens from the Cathedral Mountain Formation from USNM 702, 702a, 702un, 702inst., 702b, 71 lq, 714w, 703bs, localities that represent about the same level (that of the base of the Leonard as defined by King). Many of these specimens fall into the range of variation of the species but some have finer spines and generally are not so convex as normal for the species. Again the collection is too small to make specific differentiation. Edriosteges tenuispinosus, new species Plate 222: ficures 1-5 Large for genus, subquadrate in outline, width and length almost equal; cardinal extremities obtuse; sides and anterior margin gently rounded; lateral profile moderately convex, posterior third somewhat flattened; anterior profile broadly domed and with steep sides; umbonal region flattened; median region inflated. Surface marked by short, slender ornament spines, closely crowded and covering surface; rhizoid spines thin and delicate. Interarea long; elytridium narrow, moderately elevated. No frill. Brachial valve broadly concave, most concave in anterior third; ears flattened; lophidium elevated. Measurements (in mm).—From locality USNM 703a1, specimen 152650 (holotype): length 50.4, brachial valve length 40.0, maximum width 53.2, hinge width 41.2, height 19.7, thickness 13.6. Stratigraphic Occurrence.—Cathedral Moun- tain Formation. Locality.—USNM 703a1. Diagnosis.—Large, shallow Edriosteges with short, fine ornament spines. Types.—Holotype: USNM 152650. Comparisons—This is the largest species of Edriosteges from the Glass Mountains and differs from E. multispinosus Muir-Wood and Cooper not only in size but in being shallower and less domed in anterior profile, in having finer ornament spines, no frill, and more delicate rhizoid spines. Edriosteges species 1 A few specimens taken from the sponge reef or bioherm in the Taylor Ranch Member of the Hess Formation at USNM 702d appear to belong to Edriosteges rather than Limbella. The ornament spines are well scattered and no costellae are apparent on any specimen. All the specimens are misshapen and show the effects of living in crowded conditions. The most complete specimen is 30 mm long by 28 mm wide, but the hinge is greatly narrowed by impeded growth caused by crowding. No median sulcus is evident in the pedicle valve. The interarea is fairly long. The brachial valve is gently concave and on the inside has aborted lat- eral ridges like those of more normal species of Edriosteges. The adductor field is not thickened but the cardinal process is stout-shafted and bi- lobed. The lophidium is keeled. These specimens are of special interest because they are probably the earliest members of this genus from the Glass Mountains and possibly the oldest known anywhere. 844 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Types.—Described specimens: USNM 149068, 149146. Genus Echinosteges Muir-Wood and Cooper, 1960 Echinosteges Muir-Wood and Cooper, 1960:101.—Williams et al., 1965:H455. Large, piano- to concavo-convex, subquadrate or rectangular to subpentagonal aulostegids having spiny pedicle valve but nonspiny brachial valve; rhizoid spines abundant on ears and posterolateral margins; ornament spines short, suberect; pedicle valve tuberculate to indistinctly costate anteriorly, tubercles bearing ornament spines; brachial valve dimpled and wrinkled, spines rare. Pedicle valve with long palintrope, very narrow delthyrium and elevated elytridium; adductor scars restricted to elongated elevated platform; diductor scars flabellate, not extending anterior to adductor platform. Brachial valve with prominent lophidium; cardi- nal process moderately long-shafted, deeply exca- vated anteriorly in young, solid and massive in adults; myophore varying from narrowly bilobed to widely bilobed to massively trilobed; posterior mar- gin flattened; lateral ridges indistinct or poorly formed; adductor scars situated on thick rounded platform, anteriorly, laterally, and medially exca- vated; breviseptum originating within adductor field, extending anteriorly to slightly beyond mid- valve; brachial ridges indistinct except in old speci- mens, given off horizontally; brachial loops normal. Type-Species.—Aulosleges tuberculatus R. E. King (1931:95, pi. 27: figs. 4-7). Diagnosis.—Large Aulostegidae with long in- terarea, strong elytridium, short halteroid spines, and large brush of rhizoid spines on the ears. Comparison.—This genus stands in strong con- trast to Limhella and Edriosteges in spite of the fact that it has some of the characters of both. It differs from Limhella in its squarish outlines, the deeply and numerously dimpled brachial valve, and the numerous short halteroid spines. It differs from Edriosteges in the greater development of the palintrope and elytridium, lesser depth of the pedicle valve, and the lack of any radial ornament, which is also a distinction from Limhella. Inter- nally, the brachial valve in the type species devel- ops a strong adductor platform but not all of the species are so provided. Discussion.—This is a common genus in the Word Formation of the Glass Mountains but is ex- tremely rare in the limestone below the Getaway Member of the Cherry Canyon Formation and in the Bell Canyon Formation of the Guadalupe Mountains. In the Word Formation of the Glass Mountains it is commonest in the Willis Ranch Member, fairly common in the China Tank Mem- ber, but less so in the Appel Ranch Member. The genus first appears in the Road Canyon Formation but is rare there. In rocks of post-Word affinities the genus is excessively rare. It is known outside the United States from Word equivalents in Coahuila, Mexico (USNM 149022). This lot includes an ex- ceptionally large specimen and may represent an undescribed species, but the specimens are not well preserved. Echinosteges relies for its fixation very largely on the rhizoid spines, which are more greatly devel- oped than in most of the aulostegids of the Glass Mountains. These thick, stout spines are confined to the posterior margin, to the umbonal slopes, and to the lateral margins to midvalve or slightly be- yond. When individuals live crowded together, the posterior ends become engulfed in a tangled mass of rhizoid spines. The ornament spines are short and suberect, projecting from their tubercle obliquely to the surface. These spines are thick at the base but taper rapidly. Another feature of the exterior that needs re- marking is the frill that develops around the ante- rior margin of both valves of old specimens. Although this frill or "gutter" was mentioned in the original description among the generic charac- ters of Echinosteges, it is definitely not a generic character. Its occurrence is too spasmodic to assist in defining the genus. Furthermore, similar frills appear in other genera, either spasmodically or, in one genus, in most of the specimens seen. The frill is commonly thin and very fragile. In many speci- mens it appears only as remnants because of its fragility. In the original description of this genus (Muir- Wood and Cooper, 1960:102), some points of anat- omy were not considered in detail and a few statements need clarification. On the exterior of the shell, the brachial valve is said to have spines "very rare near hinge." Although we examined many brachial valves, none proved to have spines near the hinge. One very unusual specimen (USNM NUMBER 19 845 149019a, pi. 224: fig. 7) did, however, have large spines which, unexpectedly, prove to be rhizoid spines. These appear attached to the frill along the lateral margin of a large brachial valve. The spines are stout and thick; they grow nearly vertically from the frill for about 5 mm, after which they bend at a right angle to grow parallel to the shell surface for about an inch. They then descend with a moderate slope to attach to the surface along which they run to the opposite margin. The speci- men unfortunately is fragmentary, but no attached spines appear on the valve surface that could be identified with a possible set of spines emanating from the frill on the opposite side of the specimen. Probably this is an aberrant individual. Obviously, this unusual occurrence does not affect the defini- tion of Echinosteges as having a brachial valve free of spines. Of considerable interest on the pedicle valve are the palintrope, interarea, and the elytridium, which are best developed in this species of all the Glass Mountains aulostegids. As with all attached forms, the length and width of the palintrope and interarea are extremely variable. Some specimens that have been forced to grow squeezed tightly be- tween their fellows usually have an enormously elongated palintrope. In such specimens the elytri- dium is exceptionally well developed. The delthy- rium or cleft in the palintrope is always extremely narrow, consequently the elytridium is narrowly folded and increases in height above the interarea anteriorly. At its anterior end the elytridium is puckered and grooved to accommodate the carínate edge of the lophidium. In many specimens the an- terior end of the elytridium hangs over the lophi- dium and, in several specimens, extensions of its end are folded around the sides of the lophidium, tending to lock this structure in place. In such examples the elytridium serves fairly effectively as an articulatory device. One of the generic characters stated for Aulo- steges is the presence of small spines on the "delti- dium." This feature, which has been observed in a few specimens of Echinosteges, usually adults or old individuals, is occasionally deceptive, because spines grow from the posterior margin over the interarea and wrap over or cease growth at the elytridium. These examples appear to show the spines as emanating from the elytridium when ac- tually they do not. But in a fair number of speci- mens spines are given off directly and vertically from the narrowly rounded edge of the elytridium. These spines are hollow and open inside the valve through the elytridium. Spines from the elytridium are rare, but are used for attachment. The palintrope edge in some specimens is min- utely serrate, but no specimens were seen in which this becomes an important factor in the articula- tion. The interarea is marked by prominent hori- zontal lines of growth which interrupt vertical lines. These appear to be the growth tracks of ir- regularities along the margin. Muscles occupy the entire posterior half of the pedicle valve. The diductors are large and flabellate but never strongly impressed. The adductor field, however, is prominent because of its elevation on a long and narrow platform dividing the diductors from back to front. The diductors do not extend anterior to the front end of the adductor platform. A thin, low, delicate myophragm divides the ad- ductor platform into halves. The myophragm in many specimens is concealed by shell tissue and cannot always be observed, except in the anterior end of the platform. Four scars are visible in favor- ably preserved specimens. The two larger ones ap- pear at the anterior end, and the smaller, narrower ones at the'posterior. Both pairs commonly become dendritic with age. In some specimens the scars can be seen on the sloping side of the platform as well as on the top. The development of the adductor platform is ex- tremely variable, even in young shells. In some young adults it is only slightly elevated above the floor, but in some youthful ones it is strongly ele- vated. The age of the shelf or platform may be de- duced from the character of the scars on it. In the young, the surface of the scars is smooth and the margins fairly well-defined; but in old platforms the scars are generally dendritic, and the outline of individual muscles difficult to trace. The structure of greatest interest in Echinosteges is the cardinal process, which undergoes consider- able change from the young to the adult. In imma- ture specimens the cardinal process is elongated, extending into the body chamber at right angles to the posterior margin, and forming a tentlike struc- ture. In cross section it is triangular and is deeply excavated on the anterior side but carínate on the posterior side. The myophore is narrowly com- pressed, consisting of three unequal lobes, the me- 846 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY dian lobe being the larger; the two lateral ones are depressed anteriorly, forming ridges below the level of the median lobe, and are separated from the me- dian one by narrow grooves and the sloping lateral faces of the median lobe. The myophore occupies about the ventrad half of the posterior carínate face, the other half being the sharp edge of the lophidium. In some specimens the distal tip of the cardinal process is slightly indented medianly. When emphasized, this indentation may lead to a quadrilobate process but this is not a common con- dition. Considerable variation exists between individu- als below 5 mm length in the development of the cardinal process. In many specimens the process is small and short but in others it is robust and thick, with stout lateral pillars forming the sides. The myophore ranges from narrowly compressed to moderately expanded, with the appearance of that of a larger adult. It is possible to explain these differences as the result of living in unfavorable or in favorable environments. The more precocious processes may have devel- oped in specimens situated where food and oxygen were in proper supply; the specimens with weaker development of the process may have been under- nourished. On the other hand, those with the stouter and more advanced cardinal processes may represent individuals that are essentially adult but dwelt in an unhospitable environment for such a long period that they attained adulthood without reaching normal adult size. Specimens ranging in size from 5 to 25 mm show the same variations in development from immature cardinal processes to those types more typical of old age, even though a specimen an inch long is still young. In spite of the range, certain advances can be noted in the majority of specimens. Generally, the distal end of the process is wider than in the very young, and the median lobe of the myophore is more prominent. In all specimens observed, the anterior face is deeply excavated but the lateral walls are thicker, and in many specimens a small projection appears near the proximal base of the cardinal process wall, or nearer the middle in some specimens. These projections show incipiently in many small specimens and are seldom strongly de- veloped at a length of one inch (25 mm). No consistency was observed in the expansion of the distal end of the myophore. Some extreme ex- amples have a widely bilobed end, but the majority of specimens are only slightly expanded at a length of one inch. Many of them have scarcely advanced from the narrowly compressed stage of the very young. Brachial valves ranging in length from one inch (25 mm) to nearly 2 inches (45 mm) exhibit still greater variation in the cardinal process than the smaller valves. In general, a great thickening of the process takes place, and in a fair percentage of specimens the anterior excavation is totally elimi- nated, the shaft becoming filled and overgrown by callus. Exactly as in the smaller specimens, individ- uals of large size appear whose cardinal process shows little change from its youthful form. For ex- ample, one specimen 35 mm long has a cardinal process open anteriorly, except near the ventrad end, where it is thickened and slightly grown to- gether and the myophore is tightly compressed. An- terior points that are common in many specimens are still in an incipient condition. This specimen contrasts with another, 41 mm long, in which the anterior cavity is completely closed, and the two processes are prominent and partially cover the an- terior face. The myophore of this specimen is deeply cleft medially and the cardinal process dis- tally is strongly bilobed, the lobes widely divergent. This specimen may be compared to another of the same length but of heavy shell and massive cardinal process. A cavity appears at the base of the process and is bounded by massive lateral plates. The re- mainder of the anterior face is covered by enor- mously expanded lateral lobes of the cardinal process and a large development of the two pointed processes. The myophore of this specimen is char- acterized by a forked median lobe of moderate size with two massive lateral lobes on each side, making the cardinal process 15 mm in lateral measurement. The lophidium is correspondingly thickened and the specimen shows all signs of having had a healthy old age. The largest brachial valve in the collection is 47 mm long. It is not as thick as the preceding speci- men but has all of the marks of extreme old age. The cardinal process is about the same width as that of the preceding specimen, and the median lobe is not cleft but forms a rounded lump. The extravagant feature is the lateral lobes, which are greatly expanded and have broader attachment sur- faces than normal. The lophidium in this case is narrow and sharp. The elevated adductor platforms are an impor- NUMBER 19 847 tant feature of Edriosteges. In the youngest speci- mens available (about 5 mm long) the platforms are conspicuous but not greatly elevated. As with other features, however, this statement must be qualified. In some specimens the platforms are defi- nitely lifted above the floor and are anchored by a low plate, the platforms being excavated fairly deeply medially. In older specimens the elevation becomes higher and the supporting plate more con- spicuous. In addition the platform is excavated laterally as well as medially. In adults and old specimens the platforms are so thickened in some specimens that they coalesce, but in others they re- main deeply excavated medially. Generally in the young two scars are visible on each platform. These are somewhat teardrop- shaped and the smaller one lies on the outside of the larger. In old specimens scars become strongly dendritic, so much so, that it is usually difficult to distinguish the separate scars. Ecology.—Echinosteges lived like most of the other members of the Aulostegacea but differs from many genera in having the rhizoid spines confined to the posterior margin, umbonal slopes, and the posterior half of the lateral margin. Many aulo- stegids have anchor spines scattered on the body of the shell or along the front and anterior half of the lateral margins. Rhizoid spines have not been ob- served in these parts of Echinosteges. It is, perhaps, because of lack of anterior and lateral supports that the rhizoid spines are so thickly matted and massed at the posterior. The specimens that have been found in living position are firmly rooted by a dense mat of spines. Echinosteges guadalupensis (Shumard) Plate 229: figures 1-19; Plate 244; figures 28, 29; Plate 258: figure 30; Plate 267: figures 1^ Strophalosia guadalupensis Shumard, 1860:292, 390, pi. 11: figs. 5a, b. Aulosteges guadalupensis Girty, 1909:277, pi. 20: figs. 22, 22a. [Not of R. E. King, 1931:93, pi. 25: figs. 8-11, = Rhamnaria kingorum Muir-Wood and Cooper.] Small and delicate for genus, longer than wide, outline longitudinally sub trigonal to rectangular; greatest width near midvalve. Sides moderately rounded; hinge narrower than greatest width; an- terior somewhat narrowly rounded; anterior com- missure with gentle dorsad flexure. Interarea long, flat, apsacline. Elytridium large, long, strongly arched. Surface finely tuberculate on pedicle valve, tubercles bearing on ears and posterolateral slopes short (3.5 mm), nearly recumbent, ornament and brush of long but delicate rhizoid spines. Brachial valve finely and deeply pitted. Pedicle valve fairly evenly and gently convex in lateral profile; anterior profile broadly but moder- ately domed with sulcate median region and steep, gently rounded sides. Umbonal region narrowly in- flated with long and steep posterolateral slopes to small deflected ears. Sulcus fairly strong, originating at about midvalve and indenting anterior margin. Flanks swollen, lateral slopes steep; anterior slope moderately steep. Pedicle valve gently convex in posterior third but becoming moderately concave anteriorly, with anterior quarter abruptly deflected ventrally to form steep slope lessening laterally and posteriorly and bounding deepest concave part on each flank of low median fold. Ears slightly developed, bound- ing deepest concave part on each flank of low median fold. Median fold originating just posterior to midvalve, angular and broad. Pedicle valve interior with elongate adductor field, dendritic posteriorly and divided by low apical myophragm extending anteriorly not quite to middle of adductor field. Diductor scars sub- flabellate. Brachial valve interior with broad ginglymus or false interarea. Cardinal process primitive, with long open shaft and bilobed myophore. Lophidium keeled but not strongly developed. Adductor field not strongly developed, with no trace of platforms; breviseptum low and inconspicuous, often not visi- ble. Measurements (in mm).—Hypotype, USNM 152652a: length 33.0, brachial valve length (?), maximum width 29.0, hinge width 22.2, height 11.7, thickness (?), interarea length 7.3. Hypotype, USNM 152652n, brachial valve: length (?), bra- chial valve length 27.9, maximum width 35.0, hinge width 21.7, height and thickness (?). Stratigraphic Occurrence.—Bell Canyon For- mation (Hegler, Pinery, Rader and Lamar mem- bers), Capitán Formation. Localities.—Hegler: USNM 731, 732a, 740c. Pinery: AMNH 397; USNM 725n, 736. Rader: AMNH 403, 410; USNM 725f, 725g, 740i, 740j. Lamar: 728p. Capitán: 738a. Types.—Figured hypotypes: USNM 149407; 848 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 152652a, c, j, 1, m; 154181; 154182a. Measured hypo- types: USNM 152652a, n. Comparison.—This species is smaller, with deli- cate and more numerous spines than E. tuberculatus (R. E. King) the only other species known. The exterior of the brachial valve is more numerously and more finely pitted than that of King's species and it also has a median fold, a character not shared by the Word species. Discussion.—This is an extremely rare species in the Bell Canyon Formation. Beside the type lot from the Rader Member a few posterior portions of brachial valves were taken from several localities. The Pinery Member (USNM 725n) produced three similar specimens but it is uncertain that they are specifically the same. Some of the specimens from the Rader, at other localities than that of the types, indicate that they were larger and thicker than the type specimens, but all of them have the same open-shafted cardinal process and immature type of myophore which is a mark of the species. Specimens of Echinosteges, fully adult in size, often retain a juvenile kind of cardinal process. This is not characteristic of most species because many specimens, including ones with juvenile exterior proportions, develop elaborately lobed cardinal processes. Possibly if enough specimens of E. guadalupensis are found they may show that this species, too, developed a more advanced cardinal process in old age in a small percentage of the specimens. On the basis of the shape of the specimen figured by Shumard (1860: 390, pi. 11: figs. 5a, b), with its elongated beak, the specimens described above have been identified as Shumard's species. Similar speci- mens but with low beaks have the characters of Rhamnaria and cannot be identified as Shumard's species. Specimens were taken in the limestone as well as from the residues but it is a rare species. Echinosteges tuberculatus (R. E. King) Plate 101: figure 14; Plate 223: figures 23, 24; Plate 224: figures 1-10; Plate 225: figures 1-19; Plate 226: figures 1-18; Plate 227: figures 1-25; Plate 228: figures 1-43; Plate 229: figures 20-38 Aulosteges tuberculatus R. E. King, 1931:95, pi. 27: figs. 4-7. Aulosteges beedei R. E. King, 1931:92, pi. 25: fig. 15 [not figs. 12-14 = pi. 101: fig. 14]. Large, quadrate to subrectangular but commonly misshapen; length and width nearly equal; hinge variable, narrow to nearly equal to greatest width; sides straight to gently curved; anterior margin broadly rounded; anterior commissure faintly unip- licate; surface tuberculate and spinose. Pedicle valve with prominent tubercles covering exterior, each tubercle bearing recumbent stout ornament spine about 6 mm long or less; ears bearing tangled masses of long rhizoid spines by which shell is anchored. Tubercles on anterior slope in many specimens elongated into prominent costae. Anterior margin of old specimens provided with ventrally reflected flange, or gutter. Lateral profile unequally convex, posterior half nearly flat to gently convex, but anterior half strongly convex and with precipitate anterior slope. Anterior profile strongly domed, sides steep and long. Beak small, slightly incurved over interarea; umbo rounded to greatly elongated, moderately convex; median re- gion swollen. Palintrope long, divided by narrow delthyrium; interarea flattened or curved and ir- regular; delthyrium closed by narrow and irregular elytridium. Palintrope margin straight and un- modified. Pedicle valve interior with open and spacious umbonal chamber with elongated and strongly elevated adductor field in the middle. Four scars, inner and outer pairs, discernible; adductor scars commonly dendritic. Diductor scars seldom well impressed, broadly flabellate, not extending beyond tip of adductor platform. Anterior half pitted, marked by taleolae. Brachial valve generally square in outline, variable in profile, ranging from almost flat to slightly convex and to unevenly concave, latter examples being gently convex in posterior half but gently to moderately concave in anterior half. Exterior concentrically but unevenly wrinkled and pitted by irregular dimples corresponding to tubercles of pedicle valve; no spines observed. Interior with posterior margin thickened from cardinal process to flattened and narrowly rounded ears. Cardinal process variable, deeply excavated anteriorly; shaft short, consisting of two pillars bridged by keeled myophore in young but bilobed to trilobed myophore in adults. Adductor platforms prominent, elevated on low ridges and overhanging or pinching out median septum; platforms exca- vated laterally and medially; breviseptum extend- ing from anterior end of adductor platforms to NUMBER 19 849 beyond midvalve; brachial ridges obscure, originat- ing at anterolateral ends of adductors and extend- ing directly laterally. Anterior margin in many specimens with ventrally deflected flange, or gutter, corresponding to that of pedicle valve and outside of it. Measurements (in mm).— brachial surface hinge maximum length valve length length width width height thickness USNM 706c 149020a 53.2 ? 75.0 35.0 47.8 20.0 ? 149020b 49.1 ? 71.0 35.5 42.0 19.0 ? 149020c 39.8 ? 49.0 29.0 33.5 16.9 ? 149020d 33.8 ? 40.0 32.0 32.0 10.6 ? 149020e 30.0 ? 33.5 21.5 29.5 7.8 ? 149020f 27.7 ? 33.0 21.5 25.0 8.1 ? 149020g 24.8 ? 28.5 18.0 22.0 7.2 ? 149020h 20.2 ? 20.5 21.5 22.3 7.8 ? 149020Í 16.6 ? 18.5 13.0 16.0 3.5? ? 149020j 9.0 ? 10.0 10.0 10.5 3.0 ? 149020k 6.5 ? 7.0 7.5 7.5 1.7 ? 1490201 3.7 ? 8.5 3.5 5.0 1.1 ? 149020m 38.2 ? 41.0 44.0 ? ? 149020n 33.0 ? 35.3 39.0 ? ? 149020o 31.6 ? 26.5 35.6 ? ? 149020p 27.1 ? 19.0 22.7 ? ? 149020q 18.7 ? 17.3 21.0 ? ? 149020r 12.8 ? 13.7 14.1 ? ? 149020s 8.0 ? 6.4 8.0 ? ? 149020t 41.1 32.4 52.0 30.5 37.9 15.8 10.1 149020U 25.8 21.0 30.0 23.0 28.6 8.5 8.3 USNM 706b 149024a 48.8 35.2 56.0 37.4 45.2 17.1 13.1 149024b 58.0 41.6 88.0 45.5 59.8 36.0 28.0 Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Member), Road Canyon Formation, Word Formation (China Tank, Willis Ranch, and Appel Ranch members and lenses be- tween last two). Localities.—Road Canyon: USNM 716xa, 720d, 721j, 732j. Cherry Canyon: AMNH 21, 496, 512, 600; Moore 31; USNM 728, 730, 732. Word: USNM 732c, 732s, 741p. China Tank: USNM 706c, 713, 733q. Willis Ranch: AMNH 505, 506; USNM 706, 706e, 723t, 723w, 724u, 735c=706e. Appel Ranch: USNM 714o, 716v, 726t. Lenses: USNM 706b, 742b. Types.—Lectotype (herein designated): YPM 10608a. Figured paratype: YPM 10608b. Figured specimen: T11045. Figured hypotypes: USNM 123452; 123453a, c, k-m, p; 123905a, b, e, f, h, i, k; 149019a-j, 1, m; 149020u; 149024a, b; 149026; 1490- 39a, b; 154177a; 154178a-e, h, j-1; 154179a-d, f, g, j-1; 154180a-c, f, g, k-q; 154529. Measured hypotypes: USNM 149020a-u; 149024a, b. Comparison.—This species differs from E. guad- alupensis (Shumard) in its larger size, more robust form, stronger spines, and more advanced internal characters in the brachial valve. Type-Specimens.—R. E. King (1931:95) failed to designate a holotype for his species. We therefore select the specimen illustrated on plate 27: figure 7 as lectotype. This specimen is a large and fully mature adult from the Word Formation (Willis Ranch Member). Selection of this specimen is mandatory because King (p. 95) indicates his "types" from his locality 239. The only other specimen from this lot is fragmentary. These specimens are from the same stratigraphic level as the abundant ones from USNM 706e and those figured by Muir-Wood and Cooper (1960, pis. 14-16). Echinosteges? species Plate 258: figures 31, 32 A probable new species is represented by a frag- 850 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY ment from the Neal Ranch Formation at USNM 701. The specimen is the posterior part of a pedicle valve having a broad and flat, strongly apsacline interarea with a narrow and slightly elevated elytridium. The exterior is covered by a mat of very fine spines. This is the only trace of this genus or other aulostegid except Limhella found in the Neal Ranch Formation. The delicacy of the spines sheds some doubt on the generic assignment. Type.—Figured specimen: USNM 149045. Cactosteges, new genus [Greek cactos (prickly plant) + steges (chamber)] Moderate size, subquadrate in outline, piano- to concavo-convex with the pedicle valve of consider- able depth; anterior commissure faintly uniplicate; surface of both valves spinose, pedicle valve attached to substrate by rhizoid spines located on the ears, umbonal slopes, and lateral margins and bearing short, slender prostrate ornament spines; brachial valve with delicate erect spines; pedicle valve marked by concentric undulations and nodose spine bases arranged in concentric rows; brachial valve marked by concentric undulations, shallow pits. Pedical valve with incomplete palintrope on each side of beak separated by triangular delthyrium; palintrope marked by flat interarea; region just anterior to palintrope thickened and forming platform; pitted along palintrope margin. Inner lateral slopes marked by large internal, hollow spines; adductor scars thickened and elevated to form low platform; diductor scars truncate ante- riorly, wide, surrounding adductors and occupying most of posterior half of valve. Brachial valve with large bilobed to trilobed cardinal process with expanded myophore and thick shaft; lophidium prominent, plugging delthyrium. Posterior margin thickened and marked by irreg- ular row of nodes; median septum thin, low but extending from cardinal process shaft to beyond midvalve; brachial ridges large but indistinct; en- dospines large and in row along anterior slope. Type-Species.—Cactosteges anomalus, new spe- cies. Diagnosis.—Aulostegidae having spines on both valves, incomplete palintrope in pedicle valve, and brachial valve with prominent endospines on the summit of the anterior slope. Comparison.—At first glance Cactosteges is most like Echinosteges Muir-Wood and Cooper, but in- terior and exterior differences readily separate the two. On the exterior Echinosteges is strongly tuber- culate but it has few, if any, spines on the brachial valve. The interior differences are more numerous. Echinosteges is characterized by a broad and con- spicuous palintrope in which the delthyrium remnant is covered by an elytridium. A correspond- ing cover has not been seen in any specimen of Cactosteges. Furthermore, the palintrope hangs free over the umbonal chamber and is commonly very long in Echinosteges, but in Cactosteges the palintrope either overlies the marginal edges or is greatly thickened underneath, so that it does not hang free at all or only for a short distance. The thickenings around the palintrope of Cactosteges and their possible value in articulation is a feature not seen in Echinosteges. Inside the brachial valve important differences between the two genera are still clearer. In Echinosteges, the cardinal process of young speci- mens is strongly excavated anteriorly, the shaft is short, and the lophidium greatly exaggerated. In Cactosteges the lophidium is small in all stages, the shaft is longer, and the process is not anteriorly excavated. A difference between the septa and associated adductor platforms is also perceptible. In Cactosteges the median septum extends from the cardinal process shaft to beyond midvalve and is continuous all the way. Furthermore, the adductor scars are only moderately elevated and in the young are never anteriorly excavated. In many specimens of Echinosteges the median septum is visible only from the anterior of the adductor platform to beyond midvalve and the adductor platforms are greatly elevated and usually are deeply excavated anteriorly. In Echinosteges the brachial ridges are indistinct, as they are in Cactosteges, only appearing in old adults and never with a development of long endospines on the summit of the anterior slope, as in Cactosteges. Discussion.—Cactosteges presents some interest- ing points in brachiopod anatomy not commonly seen among productid brachiopods. One of these concerns the development of adventitious shell in the region immediately anterior to the palintrope, and its bearing on articulation of the valves. Among the productids it seems clear that the cardinal process and delthyrium are accessories to articula- tion but in some genera adventitious deposits in the form of nodes and sockets appear to have helped NUMBER 19 851 toward the same goal. In young specimens the palintrope is only slightly developed, but in adults it is fairly well marked, overhanging the deeper part of the umbonal chamber. In a few specimens the palintrope is thin enough to have been fractured where it is free and, in this condition, simulates the perideltidial area of Dunbar (in Dunbar and Condra, 1932). In most adults the palintrope is supported and thickened underneath, and a shelf of adventitious shell is built anteriorly against the under side of the palintrope, against the lateral wall of the umbonal chamber, and nearly flush with the flattened ears. This creates a shelf, underlying the palintrope on which the brachial valve rests, that is commonly marked by a row of pits along the junction of the adventitious shell and the under side of the pal- intrope. In some parts of the row the pits are shallow but in others they are fairly deep. These pits receive nodose projections from the posterior of the brachial valve. The posterior margin of the brachial valve of this species is marked on each side of the lateral slope of the cardinal process shaft by an irregular row of round nodes suggesting, in some specimens, small bunches of grapes. These nodes articulate with the sockets in the pedicle valve alluded to above and seem to be modified taleolae, although it is difficult to prove the point in silicified material. The palintrope of the pedicle valve is generally divided by a delthyrium that is fairly wide in this genus. This opening is usually plugged by the large triangular lophidium of the brachial valve, but in some specimens this plate does not suffice to close the opening. In such shells an incipient elytridium is formed, but it is seldom well developed and its presence is rare. In many specimens the narrow space between the end of the delthyrium and the beak is filled by shell material to make a solid wall against the end of the lophidium of the brachial valve. The pedicle valve musculature is not always well defined in this genus. The adductor field is usually thickened, in some cases greatly so, but the diductor scars are seldom clearly seen. The adductor scars are usually elongate, teardrop-shaped platforms, divisible, in some rare specimens, into anterior and posterior pairs. In some old specimens an additional lateral teardrop-shaped pair appears, one on each side of the main two. The diductor scars, when visible, are large and flabellate, as usual in the productids, and surround the adductor pair. Several other features of interest that appear in most pedicle valves of this genus should be mentioned. Anterior to the muscle field the median region of the interior is gently folded or thickened. This area is marked by short, oblique endospines with their pointed ends directed anteriorly. This endospinose area corresponds with that of the brachial valve. On the inside of the steep, lateral walls just anterior to the ears and extending nearly to the anterolateral extremities appear oblique elevated lines. They are undoubtedly parallel to the direc- tion of the currents entering the valve when the animal fed. A corresponding area appearing in the brachial valve is mentioned below. Another feature that appears in the same place is the one or more rows of short, hollow spines on the interior. In general, these are essentially parallel to the markings mentioned above and are open at their free end; apparently they connect with large spines on the exterior of the shell. As in most productids the cardinal process of Cactosteges is variable, so much so in some speci- mens that identification is difficult. In the youngest specimen recognized as belonging to this genus, the cardinal process extends ventrally at right angles to the posterior margin; it is without a shaft and is thickened and solid on the anterior side. The myophore is bilobed and the lobes are separated by a moderately deep reentrant. The lophidium is prominent. Adults exhibit a variety of forms, most of which retain the prominent bilobed outline when viewed from the ventral side but have developed a moderately long shaft that is oblique to the posterior margin. In the posterior side the myophore is some- what expanded and is trilobed, a large median lobe being separated by two diverging slits from the lateral lobes. In a few specimens the median lobe is so strongly developed that the cardinal process is trilobed in ventral view. Another feature of the cardinal process is the development of two pointed processes, or points, that extend anteriorly and obscure the shaft. The median ridge in the young extends to the cardinal process; in older forms it may be visible or may be obscured by medial growth of the adductor plat- forms or may be buried in shell deposit. The ears of the brachial valve are fairly prominent and flattened. They are set off from the main part of the shell by an oblique baffle that extends from the posterior margin to the lateral 852 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY margin at or near midvalve. This baffle evidently makes contact with the inner wall of the pedicle valve, where it is obliquely striated. The baffle of the brachial valve is striated like that part of the pedicle valve against which it abuts. Incurrent feeding streams may have passed through the narrow passage made between baffle and pedicle shell wall when the valves gaped. Cactosteges anomalus, new species Plate 230: figures 1-49; Plate 231: figures 44-56 Outline irregular, generally somewhat quadrate, with lateral margins slightly oblique, anterolateral margins narrowly rounded and anterior margin broadly rounded. Lateral margins just anterior to ears slightly indented. Hinge narrower than greatest width, which is near or anterior to middle. Rhizoid spines long, moderately stout, concentrated on ears and umbonal slopes but scattered along lateral margins. Halteroid spines thin and sharp, about 3 mm long. Interrupted concentric undulations marking pedicle valve and irregular concentric undulations and pits appearing on brachial valve. Brachial valve spines short and delicate. Pedicle valve unevenly convex in lateral profile, maximum convexity anterior to midvalve and posterior half or more nearly flat; anterior profile highly domed but with top flattened and sides steep. Umbo narrowly swollen near beak, gently convex and with gentle slopes laterally; median region greatly swollen, with precipitate anterior and anterolateral slopes; sulcus narrow and shallow, irregularly developed, but usually originating at or posterior to midvalve and extending to anterior margin; ears small, not prominent, forming rounded obtuse angles. Pedicle valve interior with short palintrope, flat or somewhat curved, and divided by an open delthyrium; region anteroventral to palintrope greatly thickened and roughened; ears small and usually somewhat concave; inner umbonal slopes marked by hollow tubes in rows just under margin; adductor platforms low; diductor scars large but not deeply impressed. Brachial valve fairly evenly concave, concavity varying from gentle to moderately deep; umbonal region concave; lophidium forming small triangle on posterior margin; ears small, varying from indistinct to narrowly acute. Brachial valve interior with variable cardinal process moderately long-shafted, with bilobed to trilobed myophore, the younger specimens having prominently bilobed myophore with deep median slit on ventral face but old specimens with thick trilobed myophore, the two median Jobes having coalesced to produce a single thick lobe; median septum variable, ranging from high to low but usually uniting with cardinal process shaft and extending anterior to midvalve; adductor scars elongate and somewhat teardrop-shaped, inner two usually thickened to form prominent platform that may partially obscure or squeeze against median septum. Brachial ridges obscure, oblique at point of origin and marked anteriorly by row of long endospines situated along line where anterior slope of concave valve originates. Measurements (in mm).— brachial surface hinge maximum length valve length length width width height thickness USNM 706 151297a 15.0 12.5 21.0 11.2 14.8 5.9 4.8 (holotype) 151297b 13.3 12.5 17.0 12.3 14.5 4.6 2.9 151297c 11.2 10.9 14.0? 8.7 12.5 4.1 2.3 151297d 13.3 10.8 23.0 11.8 14.7 8.2 6.0 151297e 16.4 ? 29.0 13.0 19.7 10.7 ? 151297f 15.7 ? 18.0 12.5? 18.5 5.4 ? 151297g 13.8 ? 18.0 13.9 17.3 4.8 ? USNM 706c 151299a 13.8 11.3 17.0 10.5 14.7 5.3 3.5 151299b 14.7 12.2 21.0 10.5 15.9 6.8 4.7 NUMBER 19 853 Stratigraphic Occurrence.—Road Canyon For- mation, Word Formation (China Tank and Willis Ranch members). Localities.—Road Canyon: USNM 716xa, 720d, 721 j. Word: USNM 732s. China Tank: USNM 706c, 713, 721p, 726r, 733q. Willis Ranch: AMNH 506; USNM 706, 706e, 718d, 723w, 724u, 735c. Diagnosis.—Convex, small Echinosteginae with distant strong, ornament spines. Types.—Holotype: USNM 151297a. Figured paratypes: USNM 151296a, b; 151297d-f, 151298; 154150a-c; 154151a-d; 154152a-j. Measured para- types: USNM 151297b-g, 151299a, b. Unfigured paratypes: USNM 151297a-c, 154150d. Comparison.—No other species of this genus is known with which this one may be compared. It may be confused with small individuals of Rham- naria but can be destinguished by Rhamnaria's densely nodose shell surface, each node bearing a slender spine. The effect is of a much more strongly and finely spinose shell than is usual in Cactosteges. Internally, the pedicle valve-of young Rhamnaria has a vestigial median septum, another ready distinction between the two. Discussion.—As presently constitued this species is one of the most variable of all productids. The extreme variability probably comes about because of the attached habit. This species is of about medium size for productids and when growing in crowded places may be greatly distorted. Specimens range from gently and fairly evenly convex to narrowly rounded or domed in lateral profile. The young are almost flat and even the most rotund specimens must have had this nearly flat early stage. If the young grew in such a position that the anterior always remained free, the specimen would reach maturity with a gentle lateral profile. If, on the other hand, growth started in the apertural region of a richthofeniid, the anterior margin may become deflected in its growth at an early stage and produce an individual with narrowly rounded lateral profile. Indications are that this may have happened in the majority of cases, because no consistent difference has been discovered on which to separate species in the material at hand. Cactosteges anomalus is an uncommon species at all of its localities. Most of the specimens come from the lower part of the Word Formation (Willis Ranch Member) at USNM 706, but it is neverthe- less rare at this place. Specimens from USNM 706e seem slightly larger than from the previous place and some features such as the endospines of the pedicle valve, are better preserved on them than on others from elsewhere. Genus Xenosteges Muir-Wood and Cooper, 1960 Xenosteges Muir-Wood and Cooper, 1960:111.—Williams et al., 1965:H455. Small, concavo-convex, attached; hinge variable, usually wider than midwidth; anterior commissure slightly uniplicate; outline subquadrate, varying from nearly square to transversely rectangular; surface smooth or marked by interrupted or discon- tinuous concentric wrinkles. Spines consisting of rhizoid spines only extending from posterior mar- gin, ears, and umbonal slope. No ornament spines. Pedicle valve with short interarea and open delthyrium; umbonal cavity deep; adductor field in old specimens forming triangular elevated track; delthyrium in old specimens partly closed by con- cave plate. Outer spines continued into interior in many specimens. Brachial valve interior with variable cardinal process, usually short-shafted and with bilobed or trilobed myophore; adductor scars thickened to form prominent platform in adults; breviseptum short but well elevated; no lateral ridges, but brachial ridges sloping at steep angle and commonly strongly elevated as projecting lobes; anterior slope minutely endospinose. Type-Species.—Xenosteges adherens Muir-Wood and Cooper (1960:112). Diagnosis.—Nearly smooth Aulostegidae, gener- ally of small size, having rhizoid spines only and prominent, commonly elevated brachial ridges. Discussion.—The species of this little genus are easy to recognize because of their nearly smooth exterior and the presence of rhizoid spines only, restricted to the posterior portion of the pedicle valve. The growth habit of all members of this genus is like that of most other members of the family. The umbonal cicatrix of attachment varies in size from a mere spot to covering almost all the umbonal region. Unlike most members of the family that beak and umbonal region may be thinned by close attachment. Although most specimens appear to be fairly solidly cemented by the umbonal region, many are 854 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY additionally securely anchored by rhizoid spines. The umbo of many specimens is a veritable forest of short anchor spines put out in the early stages of life. Later rhizoid spines are sent out from the ears and the umbonal slopes. Because of the small size of the specimens, most of these spines are short, but the spines in some did not stop growing after contact with the substratum. In some instances spines over 25 mm long have been measured, a length exceptional for such small shells. Xenosteges imposed itself on many host objects. It favored the interior surface of Neospirifer, Hercosia, the larger productids, and any other niche that offered protection and stability. The exterior features require little comment except for the ears. These are prominent in X. adherens Muir-Wood and Cooper but less so in other described species. Prominent ears appear to have been a feature of late adulthood. The ears of large or adult shells are usually well demarcated from the main body by a prominent change in slope and also by the strong convexity of the ear. These features are not so prominent in the Guada- lupian species, which are more nearly square or elongate. Most of the younger specimens having incipient ears that appear as posterolateral bulges. Xenosteges umbonatus, new species, generally an elongate species with subdued ears, develops strongly swollen and prominent projections in old specimens that have had favorable living condi- tions. The young specimens of most of the species show the ears more prominently on the dorsal side, where they are usually set off by a change in slope or an oblique ridge. The interior details of this genus offer some interesting features, including a general increase in the degree to which these are developed in the younger strata. In the pedicle valve the interarea is not strongly developed in any of the species. It is perhaps longest and widest in X. adherens, which attains a large size for the genus. In some speci- mens, especially large ones in which the posterior is thin, the interarea may be greatly reduced, even to disappearance. In specimens in which the interarea is well developed, as in some individuals of X. quadratus, new species, the delthyrium, which is always open to the exterior, is usually sealed on the inside by a concave plate. A few specimens of X. adherens show this plate, but not as fully developed as in X. quadratus. This small plate evidently forms a groove in which the lophidium of the cardinal process moved. Another sporadically developed feature of the interior is the presence of hollow spines on the inside of the pedicle valve. These are an extension of exterior spines into the interior, a phenomenon well developed in Cactosteges. The lateral and anterior border of Xenosteges is rounded and thickened to fit snugly into a groove around the anterior border of the opposite valve. Young pedicle valves of X. adherens are very little thickened in the umbonal cavity and it is difficult to determine the size and character of the muscle scars. In old specimens the position of the adductor field is shown by a ridge or myophragm extending anteriorly from the beak. In many old specimens the areas on each side of the ridge are thickened to form an elongate, narrowly triangular elevation. The diductor muscles, which must have lain anterolateral of this platform, were not visible in any of the specimens examined. In X. quadratus the triangular adductor field is more prominent, larger, and thicker, but the diductor scars are no clearer in this species than in the former. The elevated adductor track is a more prominent feature in this species than in the former and is strong in young adults as well as in older specimens. The adductor platform reaches it greatest development in X. umbonatus, new species, from the Guadalupe Mountains. In this species the plat- form is still wider than in the others and occupies the entire umbonal cavity. In some specimens it is so deeply excavated anteriorly as to form a separate plate above the valve floor. It is also divided medially by a moderately elevated myophragm. No clear impressions of the diductor scars are visible in our specimens of this species. Study of the members of this genus suggests a development of the adductor platform from an impression of the adductor field to a distinct and separate plate. The intermediate in this evolution is X. quadratus, in which the adductor platform is slightly excavated anteriorly. This trend culminates with X. umbonatus, new species, in which the adductor platform is a separate plate. The development of the cardinal process of Xenosteges is variable, as in other genera, but the complete story is not known. The smallest brachial valve of X. adherens is about 4 mm in length and that of X. quadratus is about 4.5 mm; neither shows NUMBER 19 855 the characteristic tentlike structure of the youthful aulostegid cardinal process. The specimen of X. adherens is thin and delicate and, seen from the ventral side, its cardinal process is bilobed and short-shafted, surmounting a broad triangular pro- jection that protrudes beyond the posterior margin. From the dorsal side it also presents a broadly triangular outline, the apex of the triangle serving as a lophidium, and from the posterior the cardinal process has a compressed, bilobed myophore. The smallest specimen of X. quadratus, seen from the dorsal side has a slight triangular projec- tion beyond the posterior margin, the lophidium, which, with the myophore, extend ventrally at right angles to the brachial valve. The myophore is com- pressed laterally and is bilobed, surmounting a short shaft. The cardinal process is bounded on each side by a swelling, or boss. Between these swellings and the dorsal side of the shell are shal- low depressions. The stage described for the smallest X. adherens is obviously an earlier devel- opment than that for X. quadratus, because later stages of X. adherens come to resemble the condi- tion described for X. quadratus. Viewed from the posterior, the cardinal process of the adult X. adherens has a narrowly triangular myophore, bilobed toward the ventral side. The shaft is short and lies across a trough formed by thickened lateral ridges on the ventral side and a thin projection of the outer layer on the dorsal side. The thickened part of the palintrope bounding the delthyrium fits into the grooves on each side of the cardinal process thus formed, and the slender, narrow lophidium plugs the delthyrium. All these features are thus accessories in the articulation of the brachial valve. Adult X. quadratus has the same essentials as the Cathedral Mountain species, i.e., the thick lateral ridges and thin outer wall with a groove between; The lophidium is somewhat less elevated but serves the same purpose. The myophore of the cardinal process varies from laterally compressed with a ventral groove on the shaft indicating bilobation, to widely V-shaped with the arms of the V curved laterally. Triloba- tion is rare. Another feature of the cardinal process visible on numerous specimens is a growth anteriorly on the ventral side of the shaft and extending from the myophore. This forms a small cone terminating in a single point. This growth is reminiscent of the two-coned growth on the shaft of Edriosteges and Echinosteges. Another variable feature of Xenosteges is the adductor platform. In X. adherens it is scarcely thickened in young adults but in old shells it is fairly elevated. In X. quadratus, on the other hand, the adductor scars are elevated on thick platforms. The scars are elongate elliptical or tear-shaped but the anterior and posterior pairs are not well differentiated. In some specimens the rims of the outer and anterior margins of the platform are excavated. No dendritic scars have been observed in this genus. In most adult or old brachial valves the brachial ridges are well developed or, in some species, extravagantly developed. As with the adductor platforms, the brachial ridges of X. adherens are generally not very prominent. In the larger and older specimens the anterior, or looped, end of the brachial ridge may be thickened and elevated slightly above the valve floor. The brachial ridges of X. quadratus are extravagantly developed. In some specimens they are elongated and elevated and they extend nearly to the floor of the pedicle valve. At their anterior ends they are somewhat spinose or serrate. The elevation is not confined to the ante- rior ends but extends to the lateral portions which connect with the elevated adductor platform. These platforms, the brachial ridges, and the breviseptum in this species are all grown together. Xenosteges adherens Muir-Wood and Cooper Plate 232: figures 1-48; Plate 233: figure 40; Plate 234: figures 28-32 Xenosteges adherens Muir-Wood and Cooper, 1960:112. Small, rarely attaining width of 15 mm.; gener- ally wider than long but varying from transversely rectangular to nearly square or rectangular. Hinge usually widest part; ears prominent and narrowly rounded; sides straight to sloping medially; ante- rior margin narrowly to broadly rounded, sulcate in old specimens. Surface nearly smooth but usually with concentric undulations concentrated on ears and sides. Rhizoid spines variable, heavier spines on outer sides; shell usually attached by beak but anchored by spines commonly attaining consider- able length. Pedicle valve strongly and somewhat narrowly convex in lateral profile; broadly convex in ante- 856 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY rior profile, with moderately sloping sides. Um- bonal region narrowly convex; median region inflated; anterior slope usually steep. Sulcus, when present, originating at about midvalve, seldom con- spicuous in young but strong in old specimens. Umbonal slopes steep. Ears large, rounded, well demarcated by steep lateral slope. Palintrope short; interarea short and commonly poorly developed. Brachial valve deeply concave, greatest concavity in umbonal region, flattening and shallowing some- what anteriorly. Ears prominent, flattened, demar- cated by short but steep ridge bounding median deeply concave region. Hinge straight, fitting close to edge of pedicle valve hinge line; lophidium prominent, plugging delthyrium; cardinal process generally short-shafted. Measurements (in mm).— brachial sur}ace hinge length valve length length width midwidth height thickness USNM 702 124128Í 11.0 ? 17.0 16.3 13.7 5.9 ? USNM 702a 124130a 10.7 9.9 17.0 15.0 14.0 5.5 3.9 USNM 703b 149230a 11.8 9.9 18.0 15.8 14.0? 5.5 3.4 149230b 9.9 8.1 15.0? 16.4 12.8 4.9 2.5 149230c 10.6 9.2 15.0 16.4 14.4 5.1 2.9 USNM 703a ¦ 149229a 11.0 9.6 17.0 17.6 15.7 5.6 4.2 149229b 10.5 9.6 15.0 14.0 12.8 5.0 3.8 149229c 10.3 9.0 14.0 12.2 11.1 4.5 3.1 USNM 702b 149228a 9.7 ? 13.5 11.5 9.7 4.2 ? 149228b 10.5 ? 17.0 14.8 12.8 5.2 ? 149228c 9.2 8.0 14.0 10.1 9.3 4.5 3.3 USNM 702 149227a 10.5 8.6 16.5 14.9 13.6 5.4 3.2 149227b 9.5 8.2 14.0 10.1? 10.1 4.5 2.8 149227c 9.4 8.1 12.5 11.2 11.0 4.4 2.6 149227d 9.1 7.6 13.0 10.8 9.4 4.5 2.7 149227e 8.3 6.5 12.0 9.4 8.3 3.6 2.2 149227f 4.1 ? 5.5 7.3 5.0 1.9 ? Stratigraphic Occurrence.—Cathedral Moun- tain Formation (Wedin Member), Cibolo Forma- tion, Bone Spring Formation. Localities.—Cathedral Mountain: AMNH 500H, 500N, 504; USNM 702, 702a, 702b, 702 inst., 702 low, 702 un, 703a1, 703b, 703bs, 708, 71 lq, 712o, 721u, 723k, 724r, 726o, 726u, 726x, 735b. Wedin: USNM 700-1, 700x, 714w, 717e, 723v, 727p. Cibolo: USNM 725v, 738f. Bone Spring: AMNH 660. Diagnosis.—Xenosteges- with shell transverse in the adult, incipient adductor platform in the pedi- cle valve and with brachial ridges only incipiently developed. Types.—Holotype: USNM 124128b. Figured paratypes: USNM 124128a, d, e, g-j; 124129a; 124130a, b. Measured paratypes: USNM 124128Í, 124130a. Unfigured paratypes: USNM 124128b, c, f. Figured hypotypes: USNM 149170; 149230c, d; 154236; 154250; 154251a-d; 154248a; 154249a-d. Measured hypotypes: USNM 149228a-c, 149227a- f; USNM 149230a-c, 149229a-c. Discussion.—Xenosteges adherens attains a much larger size than any of the other species ex- cept X. magnus, new species. It is also wide in the adult stages, has prominent ears, and the greatest width is across the ears. In these respects it differs from X. quadralus, new species, in which the length and width are more nearly equal in the adult. Other differences from X. quadralus appear on the exterior as well as the interior. The in- terarea of X. adherens is usually shorter than that of the Word species. In the pedicle valve the ad- ductor platform of X. quadralus is more strongly NUMBER 19 857 developed and its brachial ridges are usually strongly elevated, whereas those of X. adherens are only slightly elevated anteriorly in adults. The elongate form and great development of the adductor platform of the pedicle valve distinguish X. umbonalus, new species, from X. adherens. Xenosteges anomalus, new species Plate 234: figures 33-51; Plate 244: figures 38-44 Large for genus, subrectangular to semielliptical in outline, greatest width at hinge; sides varying from nearly straight to oblique anterior margin broadly rounded; ears flattened and generally small, nearly right-angled, slightly obtuse or acute; surface smooth; spines stout, usually short, few on posterior margin, umbonal region, ears, and lateral margins; all spines rhizoid. No spines on brachial valve. Pedicle valve strongly convex in lateral profile and broadly and strongly domed in anterior pro- file; beak small, slightly protruded posterior to pos- terior margin; umbonal region narrowly swollen; median region inflated; lateral and anterior slopes steep. Brachial valve moderately concave, anterior quarter strongly geniculated in dorsad direction, forming steep rim around sides and anterior; brachial valve deepest medially, umbonal region forming shallow pit. Ears flattened and small. Pedicle valve interior with short, not strongly developed interarea and well-formed angular ear baffles; delthyrium open, muscle area large; ad- ductor scars forming two parallel, elevated tracks between fiabellate diductor scars. Marginal rim moderately thickened. Brachial valve with interior structures greatly thickened in old shells; cardinal process variable, usually trilobed and moderately spreading, with well-developed lophidium but virtually no shaft developed; adductor scars thick and forming two elevated platforms in each side of breviseptum which does not extend to cardinal process. Ear baffles forming serrated, elevated ridges and ex- tending anteriorly as thick submarginal rim; brachial ridges elevated anteriorly and narrowly extended toward rim; strainer spines, few and thick. Measurements (in mm).— brachial surface hinge length valve length length midwidth width height thickness USNM 728 154241a 10.0 9.0 17.0 12.4 11.5 5.6 2.8 (holotypc) 154241b 10.6 8.7 15.0 11.4 8.3 4.9 2.0 154241c 10.9 ? 17.0 14.0 12.6 5.0 ? 154941d 10.0 ? 15.0 12.3 10.6 ? Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway member). Locality.—AMNH 512= USNM 728. Diagnosis.—Strongly convex, wide Xenosteges, with anteriorly geniculated brachial valve having a strongly thickened submarginal rim. Types.—Holotype: USNM 154241a. Figured paratypes: USNM 154240a-e, 154241b-d. Measured paratypes: USNM 154241b-d. Unfigured para type: USNM 154240c. Comparison.—This is a large convex shell that need be compared only with species of similar com- parable size, i.e., X. adherens Muir-Wood and Cooper and X. quadratus, new species. The former species is usually somewhat alate and has strongly acute ears and a hinge wider than midwidth. It is also more closely attached at the umbo than X. adlierens. The Word Formation species X. quadra- tus is more square and the interior has different details; the cardinal process is smaller, delicate, the brachial ridges are more strongly elevated ante- riorly, and the anterior border is not a strongly elevated rim as in the Getaway species. Discussion.—-This species is somewhat aberrant, when compared with others of the genus, especially in details of the interior. The exterior presents few features that are unusual except for the umbonal region, which appears not to have shared con- spicuously in the attachment of the shell because a scar of attachment is rarely visible. Most of the 858 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY pedicle valves in the collection show no evidence of direct attachment in this region. Some have short rhizoid spines, but only one specimen showed a small flattened scar. Inside the pedicle valve the interarea is not strongly developed and the delthyrium is spreading and not well defined. An important difference ap- pears in the muscle scars of X. anomalus, which has the adductor scars attached to two elevated, elongated platforms. In X. adherens these scars are thickened but are more elongated than in the Get- away species and are also more closely crowded. In X. quadratus the scars are separated by a low myo- phragm and in some specimens the anterior part of the adductor platform is excavated to form an ele- vated plate. The cardinal process of X. anomalus generally has a well-marked lophidium like that of the other species, but in one shell a clear development of a zygidium has taken place, an adaptation to a varia- tion in the width of the delthyrium. The ear baffle of the Getaway species is strongly serrated across the ear but anteriorly it forms a solid and elevated rim around the visceral region. In this species the brachial ridges are not so strongly elevated and elongated as in X. adherens or X. quadratus. This species is rare in the upper Getaway Member of the Cherry Canyon Formation. Xenosteges magnus, new species Plate 234: figures 1-27 Large for genus, transversely rectangular in out- line; widest at hinge or just anterior to hinge; sides oblique to rounded; anterior margin broadly rounded to slightly indented. Anterior commissure with slight dorsal fold medially. Interarea short and wide, gently concave, orthocline to anacline. Surface usually of concentric lamellae, thin and scaly, often preserved only in patches, and rhizoid spines, few in number, and located on posterior margin, umbonal region, sides and ears, occasion- ally on body. Pedicle valve with lateral profile moderately con- vex, greatest convexity near midvalve; anterior pro- file broadly domed with sulcate top and steeply dipping sides. Umbonal region swollen and stand- ing above ears, posterolateral slopes steep. Median region swollen. Sulcus usually fairly strong, origi- nating at about midvalve or slightly posterior, shal- low, narrow, and causing small indentation in front margin. Anterior slope fairly long and moderately steep. Brachial valve with median region forming deepest part, ears and cardinal extremities flat- tened, deflected, and separated from median con- cave region by fairly strong ridge or slope. Anterior dorsally deflected, with steep slope toward middle. Fold originating at midvalve, low and rounded. Pedicle valve interior with strongly flabellate diductors and adductors separated by low myo- phragm. Margins thickened and flattened. Brachial valve interior with small, short-shafted cardinal process; myophore trilobed and laterally compressed; breviseptum short and low; adductor field elongate with lateral scars elongate triangular. Lateral ridges variably developed, usually not con- spicuous; brachial ridges large but not thickened. Endospines in one or two rows, low. Anterior and lateral margins flat and smooth, often extended as short frill. Measurements (in mm).— brachial surface hinge length valve length length midwidth width thickness height USNM 726d 152653a 13.2 11.4 19.0 16.4 17.1 5.1 7.0 (holotype) 152653b 12.3 ? 17.0 15.5 14.5 ? 6.6 152653c 13.0 ? 17.5 16.6 16.4 ? 7.2 152653d 10.0 ? 13.5 11.1 10.4 ? 4.9 152653e ? 11.5 ? 11.7 13.2 ? ? USNM 721x 152654a 12.8 10.7 19.0 16.6 18.2 4.5 7.1 152654b 9.1 8.5 11.0 9.1 8.9 2.2 3.2 NUMBER 19 859 Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USN M 703a, 703c, 716x, 719x, 721j, 721o, 721x, 721y, 723a, 726d. Types.—Holo type: USNM 152653a. Figured paratypes: USNM 154237; 154238; 154239a, b, e. Measured paratypes: USNM 152653b-e; 152654a, b. Unfigured paratypes: USNM 153239c, d; 152653b-e. Diagnosis.—Large, strongly convex and sulcate Xenosteges. Comparison.—This species is most like the larger specimens of X. adherens Muir-Wood and Cooper, and probably descended from it. The Road Canyon species attains a larger size than the Cathedral Mountain species and is usually more narrowly umbonate and more strongly sulcate. Furthermore, the Road Canyon species has a longer interarea and a stronger fold on the brachial valve. The brachial valve interior of X. magnus has a more prominent development of the internal structures. The distinction between these two species is usu- ally one of degree. The young of X. adherens are usually more swollen ventrally than the young of X. magnus and the fully grown adult of the former is usually not so robust and has a lesser develop- ment of the fold and sulcus. The young of X. magnus are flattish but the brachial valves are generally more concave and the pedicle valves more strongly sulcate than those of X. adherens. The sulcus of the latter is variable and in many speci- mens it is scarcely developed. On the other hand, the sulcus of X. magnus is usually well developed, but a few specimens failed to develop one. Xenosteges quadratus, new species Plate 235: figures 1-60; Plate 236: figures 1-18 Shell attaining width of about 12 mm, subqua- drate in outline, width of adults slightly greater than length; sides nearly straight to gently rounded; anterior margin broadly rounded. Hinge straight, variable, seldom wider than midvalve. Ears usually not well developed. Surface marked by irregular concentric wrinkles, concentrated near ears, espe- cially on brachial valve. Pedicle valve strongly convex in lateral profile, with anterior slope somewhat steeper than posterior one; anterior profile strongly to broadly convex, lateral slopes moderately steep; umbonal region inflated; umbolateral slopes steep, demarcated from small, swollen ears by slope change. Sulcus usually absent, obscure when present. Ears narrow, lateral extremities rounded. Interarea short; delthyrium closed by concave plate forming groove for motion of cardinal process. Pedicle valve interior with wide, triangular ad- ductor platform in adults; ears forming flattened area; peripheral rim thick. Brachial valve moderately concave, deepest part in umbonal and mid regions, flattening on ears and along anterior margin. Ears flat to slightly concave. Brachial valve interior with variable cardinal process usually short-shafted and slender but thick in some specimens; myophore varying from widely to narrowly bilobed; adductor platform thickened; breviseptum short but strongly elevated; brachial ridges elongated and elevated above valve floor. Measurements (in mm).—Xenosteges qua dratus, new species: brachial surface hinge length valve length length width midwidth height thickness USNM 706 149195 11.0 9.2 15.0 10.4 12.0 5.5 4.8 USNM 706c 149197 9.5 6.8 15.0 10.5 10.8 5.5 4.0 USNM 706e 149200a 10.2 ? 16.5? 11.9 12.2 6.1 ? 149200b 10.6 ? 18.0 10.6 12.1 5.9 ? 149200c 8.6 7.6 11.0 7.9 9.0 3.3 2.1 154246a 9.3 7.0 14.0 8.4 9.6 5.0 4.4 (holotype) 860 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Member), Word Formation (China Tank, Willis Ranch, Appel Ranch mem- bers, and lenses between the last two), Bell Canyon Formation (McCombs Member). Localities.—Getaway: AMNH 21, 512, 519, 600; Moore 31; USNM 728, 730, 732. Word: USNM 732s, 737b, 741p. China Tank: USNM 706c, 713, 733q. Willis Ranch: AMNH 505, 506; USNM 706, 706e, 723t, 724u, 735c. Lenses: USNM 706b, 732c, 742b. Appel Ranch: USNM 706d, 714o, 715i, 716v, 719z, 722t, 726t, 727j. McCombs: AMNH 409. Diagnosis.—Squarish outline and extravagantly developed interior, especially the elevated brachial ridges characterizes this species. Types.—Holotype: USNM 154246a. Figured paratypes: USNM 149193; 149196; -149197; 149200a, c; 154242a, b; 154243a-d; 154244a; 154245a-c; 154246b-d. Measured paratypes: USNM 149195, 149197, 149200a-c. Unfigured para- types: USNM 149200b. Discussion.—This species is characterized by its nearly square outline and is thus easily distin- guished from adult X. adherens Muir-Wood and Cooper. The extravagant development of the in- terior of the brachial valve of adults is another readily recognized distinguishing feature. Xenosteges quadratics is generally a rare species in all of its occurrences but is commonest in a thin lens of limestone between the Willis Ranch and Appel Ranch members (at USNM 706b). It is rare in the Appel Ranch Member. Xenosteges trivialis, new species Plate 236: figures 19-56 Small to medium for genus, subrectangular in outline, width greater than length, greatest width near hinge or slightly anterior. Sides slightly oblique to gently rounded; anterior margin gently rounded. Beak small, usually truncated by cicatrix; interarea very short, anacline. Surface with con- centric undulations on ears and shell body, but not strong on anterior slope; scaly lamellae patchy. Rhizoid spines confined to posterior margin and umbo. Pedicle valve strongly convex in lateral profile, with greatest convexity near midvalve; anterior profile somewhat narrow dome with steeply sloping sides. Umbonal region narrow and strongly swollen, swelling continuing to anterior margin; lateral slopes steep. Sulcus completely absent. Ears prominent, strongly deflected from shell body. Brachial valve fairly deeply concave at midvalve with fairly steep slopes to midvalve from anterior and sides. Ears deflected and flattened. Surface like that of opposite valve. Pedicle valve interior with myophragm variably developed but with ears set off by prominent oblique ridges. Brachial valve with small laterally compressed, short-shafted cardinal process; brevi- septum low; brachial ridges slightly thickened; en- dospines few, usually low and thick. Measurements (in mm).—Thickness of holo- type 3.1; of others, unmeasurable. brachial valve mid- hinge surface length length width width height length USNM 721z 152655a 8.7 ? 10.5 11.4 4.4 14.0 152655b 8.7 ? 10.2 10.6 4.5 13.0 152655c 7.9 6.3 9.6 9.6 5.0 13.0 (holotype) 152655d ? 6.7 8.2 9.1 ? ? USNM 724c 152656a 9.6 ? 10.5 11.2 4.6 14.0 152656b 8.9 ? 10.6 11.6 4.5 14.0 Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—AMNH 501; USNM 703, 716xa, 720d, 721z, 722e, 724c, 726e, 732j, 736x. Diagnosis.—Small, variable Xenosteges with strongly swollen pedicle valve, no sulcus and swollen umbo. Types.—Holotype: USNM 152655c. Figured paratypes: USNM 152655a, d; 152656c-h. Measured paratypes: USNM 152655a, b, d; 152656a, b. Un- figured paratypes: USNM 152655b; 152656a, b. Comparison.—This species is most like X. ad- herens Muir-Wood and Cooper and is entirely different from X. umbonatus, new species, which is elongate rather than transverse. It differs from X. quadralus, new species, in its less swollen form and less corrugated exterior as well as in the ab- sence of the strongly pendant brachial ridges. It differs from small or young specimens of X. ad- herens in having a more swollen and less narrowly pinched umbonal region, stronger inner ridges defining the ears in the pedicle valve, and no trace of a sulcus on the pedicle valve or fold on the brachial valve. NUMBER 19 861 Discussion.—This is a variable species especially among specimens from USNM 724c. Some of them are very characteristic of the species but others tend toward flatter forms suggesting the young of X. magnus, new species. Furthermore, the specimens at USNM 724c tend to be smaller than those in the other localities. Xenosteges umbonatus, new species Plate 233: figures 41-62; Plate 236: figures 57-70 Productus pileolus Girty (part, not Shumard) 1909:270, pi. 29: figs. 5-7a. Shell small, outline usually elongate rectangular but becoming transversely rectangular in old age; hinge generally forming widest part; sides oblique to gently rounded; anterior margin narrowly rounded. Surface marked by concentric undulations and rhizoid spines. Pedicle valve fairly strongly convex in lateral profile, anterior and posterior slopes nearly equal; anterior profile narrowly domed. Umbo small, merging into inflated median region; lateral slopes steep and descending to swollen ears varying from small to large depending on age. Interarea short. Pedicle valve interior with broad, prominent, excavated adductor platform. Brachial valve deeply concave medially, con- cavity extending from umbo nearly to anterior margin, there somewhat shallower; median concave area bounded by oblique ridges defining ears; ridges abrupt and well-defined. Ears flattened to concave, thus emphasizing bounding ridges. Brachial valve interior with prominent adductor callosity; brachial ridges abruptly elevated but short; peripheral slope steep but short; marginal groove not well de- veloped. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 731 149217a 10.1 ? 14.0 8.0 9.4 5.6 ? 149217b 8.9 ? 13.5 7.2 8.6 4.9 ? 159217c 7.9 ? 10.5 7.0 7.1 3.4 ? 149217d 10.1 8.4 15.0 6.5 9.1 5.3 3.6 (holotype) 149217e 8.5 ? 12.0 9.3? 8.3 4.3 ? 149217f 9.4 ? 14.0 12.3? 11.1 5.6 ? 149217g 7.0 6.1 6.5 4.2 6.1 3.8 2.2 149217h 9.3 8.0 14.0 5.3 7.5 4.9 3.7 149217Í 5.9 5.0 9.5 3.4 4.8 3.0 1.3 Stratigraphic Occurrence.—Bell Canyon For- mation (Hegler, Rader, and Lamar members), Capitán Formation. Localities.—Hegler: AMNH 635; USNM 731, 732a. Rader: 725f. Lamar: 728q. Capitán: 737a. Diagnosis.—Usually elongate outline and deeply concave brachial valve but having a large adductor platform in the pedicle valve. Types.—Holotype: USNM 149217c!. Figured pa- ratypes: USNM 149217a, b, f, h; 154247a-e. Mea- sured paratypes: USNM 149217a-c, e-i. Unfigured paratypes: USNM 149217a, c, e, g, i. Discussion.—The prevailing elongate outline distinguishes this species from X. adherens Muir- Wood and Cooper and most specimens of X. qua- dratics, new species. It is possible that the Capitán species will prove to be the same as X. umbonatus, new species, when the full range of its chracters has been demonstrated. Subfamily CHONOSTEGINAE Muir-Wood and Cooper, 1960 Specialized Aulostegidae having posteriorly rugose and anteriorly costate shells. Anterior pro- jecting rim in type genus bearing a row of attach- ment spines, brachial valve with row of anterior spines or funnels. Genus in West Texas: Chonosteges Muir-Wood and Cooper, 1960. Chonosteges appears in the Decie Ranch Mem- ber of the Skinner Ranch Formation and ranges into the Road Canyon Formation. In the Sierra 862 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Diablo it occurs in the Bone Spring Formation. The genus is seldom abundant but is commonest in parts of the Cathedral Mountain Formation. Genus Chonosteges Muir-Wood and Cooper, 1960 Chonosteges Muir-Wood and Cooper, 1960:113.—Williams et al., 1965:H457. Semicircular to subpentagonal in outline; hinge straight, nearly equal to midwidth; ears poorly defined; shell attached by beak and anchored by elaborate rhizoid spines on ears, umbonal slopes, and anterior margin of pedicle valve; interarea variable, usually fairly long; elytridium narrow and convex; both valves strongly geniculated. Visceral disc region of pedicle valve marked by small, rounded spine bases bearing long slender ornament spines; visceral disc region of brachial valve marked by dimples corresponding to spine bases of opposite valve; brachial valve with row of short curved tubes or erect funnels on margin. Anterior slopes of both valves costate, and anterior margins with smooth border, that of pedicle valve overlap- ping that of brachial valve. Pedicle valve interior with adductor field forming narrow elevated track between diductor scars; anterior margin with row of blunt spines, each spine occupying position between costae of anterior slope. Brachial valve interior with narrow lophidium and long-shafted cardinal process with prominent antron and bilobed or trilobed myophore. Adductor field small, moderately thickened, anterior pair of scars larger and tear-shaped; breviseptum short, highest anteriorly but not extending beyond mid- valve; visceral disc defined by thin, high subperi- pheral rim bearing row of long slender spines. Type-Species.—Aulosteges magnicostatus Girty (1909:278). Diagnosis.—Anteriorly and regularly costate Au- lostegidae with anterior row of rhizoid spines on pedicle valve and row of tubes or funnels on margin of brachial valve. Comparisons.—This genus may be confused with Urushtenia, or Strophalasiella, neither of which has yet been found in North America. Urushtenia is a Russian Permian genus, strongly geniculated and with strongly costate anterior and lateral slopes but the visceral disc regions of both valves are marked by strong concentric wrinkles and the pedicle valve does not have an interarea. Strophalosiella strongly resembles Chonosteges in outline and details of the ornament but is not provided with the elaborate row of rhizoid spines on the pedicle valve, nor with the funnels or tubes on the brachial valve. This genus seems to have been content with the smooth thickened band on the anterior of the valves, that of the pedicle valve overlapping the one on the brachial vaive as in the American genus. The interior details of Stropha- losiella are not fully known, but a cast of the inte- rior of a specimen from Japan indicates arrange- ment of the muscles different from that in Chonosteges. Discussion.—Chonosteges, like most of the Aulostegidae, was attached by the beak of the pedicle valve in early growth stages. The cicatrix of attachment is variable in size and position. In some specimens the cicatrix takes up most of the umbonal slope directly anterior to the beak, but in others it occupies one or the other of the umbolateral slopes. Eccentricity of the cicatrix is fairly common. The attachment (rhizoid) spines of this genus are of unusual interest because the shell was very securely fastened by anchor spines which are given off from all parts of the shell except the visceral disc. Young shells, before geniculation takes place, are anchored by beak ornamentation and spines from the posterior margin and the ears. After ge- niculation takes place and the anterior costae are initiated, spines may be given off from several points on the costae especially near the place of geniculation. After adulthood has been attained and before the anterior border is completed, the major and most important set of anchor spines is sent out. These take off from each costa on the anterior and lateral slopes just posterior to the border. These spines may be of considerable length, especially those on the anterior margin, which may have to grow for a long distance to make contact with the substrate. Anchor spines may be given off at any point along the anterior costae, apparently without plan, but are commonest near the angle of geniculation. These spines are usually short, because the pedicle valve surface is close to the substrate before geniculation takes place. Ornament spines have a smaller diameter than the rhizoid spines, and are most abundant on the visceral disc region but are not confined to it. They also are given off from the costae of the anterior and lateral slopes but are not numerous in these areas. Ornament spines are sent off at a low angle (20°) to NUMBER 19 863 the surface of the visceral disc and have a gentle curve. One specimen about 10 mm long has ornament spines 8 mm long. When Chonosteges is in living position, the ornament spines form a forest on the under surface and protrude from some distance between the rhizoid spines. The most unusual adornment of this genus is the tubes or spines on the brachial valve that grow in a row around the margin from ear to ear. These may take the form of curved tubes or erect funnels, the latter evidently much rarer. From present infor- mation these tubes or funnels are not a specific character. Forms with curved tubes are common at USNM 702un, but one unusual specimen with much expanded funnels was taken at the same locality. These structures appear at the anterior ends of the costae on the inside of the geniculated slope. In most specimens they are broken and only the proximal ends can be seen but, in the few well- preserved specimens available, the tubes extend dorsally for a short distance, perhaps a millimeter or slightly more, but then are bent anteriorly. In some specimens the bend is merely a slight inclination but in others it is more than a right angle. In such cases the tubes are actually directed posteroven- trally. In a few specimens the tubes flare slightly at the distal end but in most of them no distal change in diameter is apparent. A few, however, have been noted to taper distally, but these are uncommon. The curved tubes range from 3 to 5 mm in length. In a few specimens the tubes are upright and their distal ends flare into funnels so crowded that they have the appearance of a pipe organ. The funnels are irregular in shape, some having a stem of moderate length, others flaring directly from the end of the costa from which it extends. The funnels or tubes are hollow throughout and open proximally into the posterior wall of the gutter formed by the smooth recurved anterior border of the shell. When the animal was in feeding position with the valves open, this gutter was full of sea- water. Although the anterior slopes of both valves are strongly costate, their margins are defined by a band that is smooth on the outside surface. The thickened smooth band on the pedicle valve attains a maximum width of 6 mm, extends from ear to ear, and is entirely smooth. It is usually a millimeter or slightly more in the direction of valve length. The costae end abruptly at the posterior edge of this border and have the appearance of being truncated by it. This part of the pedicle valve fits into the gutter formed by the smooth anterior band of the brachial valve. The band on the brachial valve is likewise smooth but is wider than that on the pedicle valve and fits closely over it. A gutter, or grove, is bounded by the band of the brachial valve and acts as a socket for the band of the pedicle valve. The tubes or funnels of the brachial valve open into the gutter. As explained below this gutter and the band of the pedicle valve were important to the animal in feeding. The costae on the slopes of both valves appear anterior to the visceral disc just before geniculation. The disc area is obscurely costate on both valves. The pedicle valve is marked by the bases that bear the ornament spines, and the brachial valve is marked by shallow dimples which seem to corre- spond to the spine bases of the opposite valve. The spine bases are elongate but low and give the appearance of interrupted costellae. On the brachial valve the costae appear before geniculation but are usually not as strongly marked as on the anterior slope. The palintrope of Chonosteges is usually well developed. It is generally a thin and delicate plate divided medially by a long and narrow delthyrium. This is closed by a delicate elytridium, well rounded, moderately elevated, and usually undistorted. Of considerable interest is the buttress for support of the palintrope built on each side near the ears. This is a callus structure, platelike in form, underneath the lateral ends of the palintrope but built medially for some distance. This extends as a curving ridge from each end of the palintrope onto the lateral wall of the valve for a short distance. These features are variously developed, strong in some specimens but poorly developed in others. A feature of considerable interest on the inside of the pedicle valve is the row of short but needlelike spines around the entire margin. These spines are a feature of the smooth anterior rim described above. The rim of the pedicle valve fits into the gutter like margin of the brachial valve. These spines plug the openings of the tubes or funnels that open into the gutter of the brachial valve. Each spine on the anterior margin of the pedicle valve occupies a position on the smooth border opposite the groove between costae. In this way the spines fit into the holes of the funnels of the opposite valve that 864 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY occupy the ends of the costae. Inasmuch as the costae of one valve fits grooves in the other, the spines of the pedicle valve must occupy a/position opposite the grooves between the costae of the pedicle valve. Structures of the interior of the brachial valve such as the cardinal process are variable as in most of the Aulostegidae. The young cardinal process is typically aulostegid, consisting of two oblique plates that form an inverted V surmounted by a narrowly compressed, bilobed myophore. The adult cardinal process is long-shafted and usually shows the re- mains of the antron in the form of a deep longitudinal groove or cavity. Thus, on the ventral face the bilobed character is strongly exhibited. Some specimens show an anterior growth on this face that is reminiscent of the two-pronged callosity so strongly developed in Echinosteges and Edrio- steges. This is not well developed as a rule and is generally rare. The posterior or myophore face of the cardinal process is different from most members of the Aulostegidae in the construction of the lophidium. It is deeply excavated between the myophore and the posterior margin which protrudes conspicuously beyond the lateral ridges. The lophidium is a narrow ridge occupying this depression. It thus extends from the posterior margin to the myophore and is bounded by narrow but deep depressions. The myophore is short and usually bilobed, but some are trilobed, or even quadrilobed, and di- vided from the lophidium by a small curved plate (zygidium) that fits snugly against the anterior end of the elytridium. The zygidium is not developed in young specimens in which the myophore is long and narrowly compressed. In these specimens the carinate face of the cardinal process makes the lophidium, and the lateral depressed areas are not developed. In some older specimens the lateral ridges, which are not usually strongly developed in this genus, are welded to the cardinal process. In these the cardinal process, viewed from the dorsal side, appears to be broad flattened plate. The visceral disc in old specimens is marked by a thin elevated rim that divides the flat disc from the abruptly geniculated anterior slope. The edge of this rim that faces the ventral valve is scalloped, and each tooth of the scallop is extended into a long, needlelike spine attaining a millimeter or more of length. Each spine is situated posteroventral to the ridge separating the funnel openings in the gutter. They are thus located between the costae of the exterior. When the two valves are in contact, the spines lie along the internal grooves created by the costae of the anterior slope. In feeding gape, these spines would pull out of the funnels, allowing water to enter; when the valves closed, the spines sealed off the funnels, much as needle valves. As mentioned above the front margin of the brachial valve is recurved in a ventral direction to form a groove bounded by a smooth outer wall. The inner wall of this groove or gutter is the corrugated surface of the anterior slope. The inner corrugations correspond to the grooves between the costae of the exterior. The costae on the outside carry the tubes or funnels but these open to the inside of the gutter at the end of the pits formed by the inner corrug- ations. These pits receive the spines and serations at the margin of the pedicle valve. The brachial ridges of Chonsteges are like those seen in other Aulostegidae but they are not strongly impressed, except in old individuals. The breviseptum is short and is highest at its anterior end. The adductor field in young shells may be moderately thickened, but in old specimens the scars of the muscles may be fairly deeply impressed. Young Chonosteges attaches by the beak or umbo of the pedicle valve and forms a small saucer-like body. As growth continues it becomes more nearly vertical to the surface of contact. Near adulthood the anterior parts geniculate and the shell becomes more firmly anchored. As explained under Echino- steges, adulthood is not a function of size: some specimens attain this state at a small size, far smaller than normal for the species, but others do not reach adult characters until they have attained their maximum dimensions. Chonosteges was more elaborately safeguarded in its feeding than other Aulostegidae. The compli- cated set of anterior spines, gutters, and plugs is unique to this genus. The spines on the margin of the pedicle valve that are inserted into the inner opening of the tubes or funnels in the gutter of the brachial valve suggest that the funnels may have been brought into the gutter when the valves opened but the extent to which they opened must have been very small. The plugs for the funnels were possibly needed to seal the funnels against entrance by tiny predators. NUMBER 19 865 Chonosteges costellatus, new species Plate 242: figures 1-49 Aulosteges magnicostatus R. E. King, 1931:93, pi. 25: fig. 4(?). Small for genus, wider than long, hinge usually widest; sides gently rounded; anterior margin gently rounded to nearly straight; cardinal extrem- ities approximately right angles and with minute ears. Interarea moderately long; palintrope apsa- cline. Ornamentation of pedicle valve consisting of scattered, coarse spine bases and concentric wrinkles in umbonal region, becoming costate just posterior to midvalve; anterior slope costate, costae fine and regular and separated by grooves of about same width as costae; anterior margin thickened, short, about one millimeter or less; costae numbering 28 or 30 on fully grown individual. Brachial valve pitted in posterior half but costate anteriorly; an- terior margin with smooth border and gutter; outside anterior edge provided with erect funnels 2 to 3 mm long, with short, narrow stems, but gradually widening cups. Pedicle valve with angle of geniculation nearly right angle; visceral disc region nearly flat and an- terior slope nearly flat; beak and umbo small; lateral slopes steep; ears poorly defined; median sulcus variable in development, usually wide and shallow, slightly indenting the anterior margin. Pedicle valve interior not seen. Brachial valve nearly flat except for geniculation which is short and deep; median region slightly concave. Brachial valve interior with massive car- dinal process for small shell; adductor field fairly large, scars with slightly thickened rims. Brachial impressions lightly impressed. Measurements i (in mm).— brachial surface hinge maximum length valve length length width width height thickness USNM 703a1 149275a 11.3 8.7 19.0 12.0 13.6 7.0 5.8 149275b 8.9 8.0 15.0 10.8 12.0 5.4 3.9 149275c 10.6 8.2 17.0 10.0 11.8 6.4 4.9 149275d 11.5 9.3 18.0 11.4 12.9 7.0 4.3 149275e 10.7 9.0 16.0 14.0 14.6 5.9 3.3 149275f 8.8 8.0 15.0 10.0 11.8 5.3 3.8 149275g 8.8 8.0 13.5 8.5 11.0 4.9 2.9 USNM 726o 152661a 11.9 8.7 19.0 13.9 14.5 7.2 4.4 (holoi 152661b 11.4 10.0 17.5 12.5 14.4 7.0 4.6 152661c 10.5 9.3 16.0 13.0 13.0 5.6 3.8 Stratigraphic Occurrence.—Cathedral Moun- tain Formation, Road Canyon Formation. Localities.—Cathedral Mountain: USNM 702, 702un, 703a*, 703b, 712o, 723k, 726o, 726u. Road Canyon: 702c, 703a, 721r, 721x. Diagnosis.—Fairly convex, small to medium size, with fine and regular costae. Types.—Holotype: USNM 152661a. Figured paratypes: USNM 149275e, f; 154168a-e; 154169a- h; 154170a, b. Measured paratypes: USNM 149275a-g; 152661b, c. Unfigured paratypes: USNM 149275a-d. Comparison.—Chonosteges costellatus is most likely to be confused with some forms of C. varia- bilis, new species, especially those with finer costel- lae than usual for the species, it is generally a more convex species than C. variabilis, and it is also characterized by a slight but unmistakable median sulcus that forms a sinuation or flattening of the median region. This is generally not seen in the other species. Generally larger size and stronger costae separate this species from C. magnicostatus (Girty). Chono- steges limbatus, new species, is usually somewhat smaller than C. costellatus but differs in having the strong anterior band and in a more convex lateral profile. C. multicostatus, new species, is totally unlike C. costellatus. Chonosteges costellatus is not widely distributed either geographically or stratigraphically. It is 866 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY known only from the upper part of the Cathedral Mountain Formation, in which it occurs commonly with CoUemataria in a zone just under a bed abounding in Edriosteges. Specimens from the Edriosteges beds at the base of the Road Canyon Formation are also referred to this species. Chonosteges limbatus, new species Plate 240: figures 1-14 Small for genus, wider than long, hinge widest, or slightly narrower than midwidth; sides gently rounded; anterior margin broadly rounded; cardi- nal extremities acute to narrowly rounded. Pedi- cle valve with widely scattered ornament spines; costae originating on geniculated slope, numbering 24 on large specimens, and anterior band excep- tionally long. Brachial valve with anterior band of usual length. Pedicle valve with geniculation near right angle or slightly greater; visceral disc region slightly swol- len; lateral slopes moderately steep; sulcus percep- tible in few specimens. Brachial valve gently concave, greatest concavity in midregion. Interior details not known. Measurements (in mm).—From locality USNM 702d, specimen 149285a (holotype): length 10.0, brachial valve length 8.0, surface length 17.5, hinge width 11.9, maximum width 12.1, height 6.3, thickness 4.5. Stratigraphic Occurrence—Hess Formation (Taylor Ranch Member), Skinner Ranch Forma- tion (top, and Poplar Tank Member), Bone Spring Formation. Localities.—Taylor Ranch: USNM 702d, 702e; Skinner Ranch: USNM 707, 723s, 733j, 739g. Pop- lar Tank: USNM 741k. Bone Spring: AMNH 492, 634; USNM 728g. Diagnosis.—Chonosteges usually of small size, having a long front border. Types.—Holotype: USNM 149285a. Figured paratypes: USNM 154156a, b. Discussion.—This species is distinguished from all others in the Glass Mountains by its small size and the great length of the anterior border. The latter feature is variable, because the younger specimens are not provided with an exceptionally long border, but the adult forms are usually strik- ing in this respect. This species was collected in silicified condition only in the "Fossil bed" of P. B. King, where it occurs in the sponge reef at USNM 702d. It is probable that specimens taken at USNM 702e, where sponges are rare, were dead shells that originally lived among or on the sponges. In any case, the species is uncommon. Chonosteges magnicostatus (Girty) Plate 244: figures 1, 2 Aulosteges magnicostatus Girty, 1909:278, pi. 31: figs. 4, a, b. The type specimen of this species is so poor and so unusual that reference of other specimens to it is very uncertain. The specimen is small and longer than wide, an unusual feature for normal speci- mens of this genus, which are generally wider than long. Furthermore, the interarea is about 2 mm long, an unusual length for such a small specimen of the genus. Nineteen costae can be counted along the margin, but this is not the total number be- cause at least one on the left side cannot be seen and those in the vicinity of the left ear are covered by matrix. The specimen probably has 24 costae. Among the numerous collections of Chonosteges available for study we are unable to find any that compare favorably with this specimen. The vast majority of specimens are wider than long, unless obviously distorted by living under inhospitable conditions. Girty's type specimen is the only one he had. Furthermore, the locality USGS 3840 (green) and zone from whence it came are un- known. Its location is given as "Delaware Mountain Formation, mountains northwest of Marathon, Texas." It is thus impossible, at present, to get any help from either paleontology, geography, or stratigraphy in making the status of C. magni- costatus more certain. Type.—Holotype: USNM 118548. Chonosteges matutinus, new species Plate 240: figures 15-33 Small for genus, slightly wider than long, outline subrectangular; hinge equal to or slightly wider than midwidth; sides gently rounded and slightly oblique; anterior margin broadly rounded. Inter- area moderately long, elytridium long, narrowly convex. Beak fairly long in some specimens. Costel- lae numbering 22, broad, rounded, crowded and with narrow interspaces. Spines not preserved. Brachial valve strongly geniculated in lateral profile, posterior half behind geniculation, flat or flatly convex, but anterior or geniculated half, flat- NUMBER 19 867 tened to moderately convex. Umbonal region moderately swollen; ears deflected, small. Pedicle valve mostly flat, umbonal region elon- gate, swollen; concentric lamellae and pits strong; geniculated part costellate. Interiors unknown. Measurements (in mm).—Thickness of holo- type 2.6, of other specimens, unmeasurable. brachial valve mid- hinge surface length length width width height length USNM 707a 149307a 7.3 ? 8.0 10.6 3.2 13.0 149288a 7.8 ? 7.9 9.0? 4.0 12.0 149288b 8.2 6.8 8.7 10.5 4.0 12.0 (holotype) Stratigraphic Occurrence.—Skinner Ranch Formation (Decie Ranch Member.) Localities.—USNM 707a, 727u. Diagnosis.—Small, strongly costellate Chono- steges. Types.—Holotype: USNM 149288b. Figured paratypes: USNM 149307a, b; 149288a. Measured paratypes: USNM 149307a, 149288a. Comparison.—This species needs to be compared only with C. limbatus, new species, which is the next largest of the species described here. The Decie Ranch species differs in having the length and width more nearly equal, in having slightly less costellae, and in having a narrower band at the anterior in the adult. Discussion.—Our extensive collecting in the Decie Ranch Member resulted in the acquisition of only eleven specimens of this species. It is also the lowest level at which the genus was taken. Chonosteges multicostatus, new species Plate 240: figures 34-51 Large for genus, wider than long, wide hinge equal to or slightly less than greatest valve width just posterior to midvalve. Sides nearly straight to gently rounded; anterior margin broadly rounded; interarea moderately long. Ornamentation of pedicle valve fine in details, with visceral disc covered by numerous fine concen- tric wrinkles bearing small nodes with long hair- like ornament spines. Ornament spines confined to visceral disc and posterior part of anterior slope; geniculated area and anterior slope costate, costae slender and crowded, about 36 on large specimens; spaces between costae narrower than costae, ter- minating in small but deep pit. Anterior border short. Brachial valve with entire visceral disc marked by fine concentric wrinkles, uneven and discon- tinuous and pitted by small dimples. Anterior border longer than on pedicle valve but short, measuring about 1.5 mm in large specimens. Outer edge of border provided with row of large, narrow- stemmed rapidly enlarging funnels having length of about 3 mm and maximum diameter of 1.5 mm. Pedicle valve strongly geniculated, visceral disc gently inflated in lateral profile; anterior slope nearly flat in profile; anterior profile broadly domed but flattened on top, sides steeply sloping. Ears small. Beak small forming an angle of about 110° to 120°. Brachial valve nearly flat but umbonal region forming shallow concavity nearly to midvalve; ears slightly depressed and flattened. Brachial valve in- terior with large and wide cardinal process; mod- erately thickened adductor field and elevated bladelike breviseptum. Subperipheral rim thick- ened and strongly elevated laterally but depressed low medially. Measurements (in mm).—From locality USNM 703bs specimens 149301c (holotype) and d, respec- tively: length 11.0, 13.3; brachial valve length 9.9, 10.5; surface length 14.5?, 22.5; hinge width 14.0, 16.4; maximum width 14.9, 17.4; height 5.2, 7.9; thickness 3.9, 5.1. Stratigraphic Occurrence.—Cathedral Moun- tain Formation. Locality.—USNM 703bs. Diagnosis.—Large Chonosteges with numerous fine costae and with large, erect funnels on the brachial valve. Types.—Holotype: USNM 149301c. Figured paratypes: USNM 149301a, b, d-f. Measured para- type: USNM 149301d. Discussion.—This species is characterized by its large size and fine costae. In size it is equal to about the largest of the specimens of C. variabilis, new species, but can be readily distinguished from that species by the much finer costae. It also differs from C. variabilis in being proportionally wider, and the anchor spines, in conformity with the fineness of the costae, are more slender and delicate. Chonosteges multicostatus suggests C. magnico- status (Girty) which is likewise finely costate and has erect funnels on the brachial valve but no speci- mens of the latter have been seen that even ap- proach the size of C. multicostatus. Proportionately 868 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY thicker anchor spines characterize C. magnicosta- tus. No confusion is likely between C. multicostatus and the other known species of Chonosteges, be- cause none of these attain the large size nor are they as numerously costate as C. multicostatus. Chonosteges multicostatus is known from a single locality only, where it occurs with Agelesia triagona- lis (R. E. King), which is abundant there. At this place, which appears to be a local bioherm with its own peculiarities, Chonosteges is rare, and so are all other species except Agelesia triagonalis. Chonosteges pulcher, new species Plate 241: figures 1-52; Plate 244: figures 3-22 About median size for genus, wider than long, maximum width near midvalve; hinge wide and straight, usually slightly less than greatest valve width; cardinal extremities usually slightly greater than right angle, narrowly rounded, sides gently rounded; anterior margin broadly rounded. Palin- trope usually apsacline; interarea moderately long. Pedicle valve with geniculation slightly less than right angle; lateral profile unequally convex, vis- ceral disc gently convex, geniculated area narrowly but strongly convex, anterior slope gently convex. Anterior profile broadly convex, maximum eleva- tion of profile gently rounded to flattened. Lateral slopes steep; beak small, commonly elongated and misshapen; sulcus shallow, wide, seldom prominent, confined to anterior slope. Pedicle valve ornament on umbo and umbonal slopes consisting of elongate pustules bearing ornament spines, pustules cancellated by concen- tric undulations; visceral disc anteriorly costate and partially cancellated by concentric undulations; anterior and lateral slopes costate, costae number- ing 28 at maximum; costae narrowly rounded, steepsided, interspaces equal in width to costae or slightly wider. Costae ending on smooth band with surface at slight angle to valve surface, giving illusion of underlying costae. Length of band (measured in line with length of shell) 1 mm or slightly more. Anterior edge scalloped, each high point bearing long, needlelike spine. Pedicle valve interior with only slight thickening across ears and modest development of adductor track. Brachial valve nearly flat or perceptibly concave; umbonal region frequently concave; angle of genic- ulation abrupt; surface intricately marked by can- cellated concentric undulations and radial costae complicated by dimples corresponding to spine- bearing pustules of opposite valve; costae appear- ing near midvalve. Anterior gutter deep and nar- row; anterior band variable, attaining length of 2 mm but usually narrower. Outer edge of gutter provided with blunt spines commonly closed to ex- terior, but few specimens with scattered narrow open tubes or longer closed spines. No elaborate funnels seen, majority of specimens with closed spines. Measurements (in mm).— brachial surface hinge maximum length valve length lengtfi width width height thickness AMNH 504 149294 11.3 8.5 20.0 12.8 13.8 7.4 4.4 (holotype) USNM 714w 149279a K.4 7.6 3 11.2 11.8 5.2 3.8 149279b 9.4 7.9 14.0 11.2 11.2 5.0 3.0 149279c 8.7 7.5 14.0 10.3 11.3 5.1 3.3 149279d 9.5 7.0 12.0 9.6 10.1 3.4 2.8 USNM 717e 149280a 10.7 ? 20.0 14.9 15.2 6.7 ? 149280b 8.0 7.6 16.0 11.7 12.2 5.5 3.7 149280c 9.8 8.2 15.0 10.9 11.6 5.4 3.6 USXM 708 149276a 9.4 7.8 13.0? 10.6 11.6 4.6 2.8 USNM 725v 152662a 11.0 ? 15.0 13.2 13.2 4.7 ? USNM 727p 154164b 10.0 9.0 16.0 11.5 13.0 5.5 3.5 NUMBER 19 869 Stratigraphic Occurrence.—Cibolo Formation, Bone Spring Formation, Cathedral Mountain For- mation (Wedin Member). Localities.—Cibolo: USNM 725v. Bone Spring: AMNH 660. Cathedral Mountain: AMNH 500, 504; USNM 702, 708, 712o, 714w, 721u, 723u, 726o, 726u, 727q, 731b. Wedin: USNM 700-1, 700x, 717e, 723v, 727p; Moore 23. Diagnosis.—Small to medium Chonosleges hav- ing about 28 costae and provided with erect funnels on the brachial valve. Types.—Holotype: USNM 149294. Figured para- types: USNM 149280b, c; 154157a-g, i, 1; 154163a-d; 154164a-c; 154165a-d; 154166; 154157a. Measured paratypes: USNM 149276a, 149279a-d, 149280a-c, 152662a, 154164b. Unfigured paratypes: USNM 149280a; 154157h, j, k. Discussion.—Because of the finely costate ex- terior of this species it is directly comparable only to C. costellatus and C. multicostatus, new species. It is generally smaller and proportionally finer ribbed than C. costellatus and is smaller and much differently proportioned than C. multicostatus, which geniculates at a point about 10 mm from the beak. Chonosteges pulcher geniculates about half this distance from the beak. Chonosteges pulcher is not common. It occurs with Institella in the western part of the Glass Mountains on the Decie Ranch, on the north flank of Dugout Mountain, and in a fault block (USNM 708) on the Hess Ranch. In the latter of these places it is rare but is fairly common in the exposures on the Decie Ranch. Chonosteges variabilis, new species Plate 212: figures 1-10; Plate 243: figures 1-21; Plate 245: FicuREs 1-16?, 17-38 Aulosteges magnicostatus King (not Girty), 1931:93, pi. 25: figs. 1-3. Chonosteges magnicostatus Muir-Wood and Cooper (not Girty), 1960:113, pi. 20: figs. 1-9; pi. 21: figs. 1-6. Large for genus, plano-convex, subsemicircular in outline; hinge straight, variable, normally widest part of shell but frequently distorted; cardinal ex- tremities narrowly rounded or angular, nearly at right angle; sides gently curved and usually sloping slightly toward the midline. Anterior margin broadly rounded to nearly straight medially. Cica- trix small to large, frequently off-center. Interarea variable, usually short. Ornamentation variable, visceral disc of pedicle valve marked by small, elongate spine bases bear- ing long ornament spines, arranged in quincunx. Posterior two-thirds of visceral disc area of brachial valve marked by shallow dimples. Ornament spines more distantly arranged on anterior slope but con- fined to costae; all ornament spines given off at low angle to shell surface (20°). Costae originating on pedicle valve at angle of geniculation, narrowly rounded and separated by grooves about as wide as costae; number of costae variable, average-sized individuals having about 24, but as many as 30 on exceptional specimens. Costae appearing on an- terior third of brachial valve. Anterior smooth, border usually short (in relation to the valve length) in both valves, usually 1 mm or slightly more, but much longer in unusual specimens. Brachial valve with row of tubular spines attain- ing length of 4 mm, curved over anterior margin and directed posteroventrally. Rare specimens with erect funnels. Pedicle valve with uneven lateral profile, visceral disc region generally slightly to moderately convex; geniculated part narrowly convex and occurring at about two-thirds valve length from beak; anterior slope steep, angle of geniculation about 85°. An- terior profile broadly convex, median region some- what flattened, sides sloping steeply. Beak small; umbonal region narrowly convex but merging abruptly into general convexity of visceral disc region. Ears inconspicuous; sulcus usually obsolete, shallow in small percentage. Brachial valve flat to gently concave to point of geniculation, there bent at angle of about 85°. Trail steep, longest at midvalve, descending posterolater- ally; ears poorly defined, flattened. Pedicle valve interior with moderately thickened adductor field; moderately developed callus sup- ports to palintrope; marginal spines moderately long. Brachial valve interior variable, commonly moderately thickened, usually showing remnant of antron; adductor field moderately thickened or deeply impressed in old shells; brachial ridges rarely well-developed; submarginal rim usually well formed, with long spines, most elevated laterally but shorter medially where rim is low and sulcate. 870 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brachial surface hinge maximum length valve length length width width height thickness USNM 703a 149252a 14.6 ? 20.5 19.8 20.6 6.7 ? 149252b 13.8 11.7 20.0 13.4 16.2 6.7 4.3 USNM 702b 149257a 11.3 9.4 17.5 13.8 14.3 6.2 3.3 149257b 10.2 8.1 16.0 11.9 13.0 5.8 3.7 149257c 11.2 8.9 16.5 9.7 11.3 5.0 3.9 USNM 702un 149259a 11.4 10.0 18.5 13.6 15.0 6.5 4.7 149259b 11.8 9.1 18.0 10.8 13.5 6.5 4.5 149259c 10.3 8.1 15.0 11.9 12.5 5.5 3.9 149259d 9.6 7.3 12.5 9.5 10.6 3.4 3.0 USNM 702a 149251a 13.8 10.6 24.0 13.8 16.0 8.2 6.0 149251b 10.2 8.6 16.0 9.8 12.8 5.7 3.0 149251c 10.5 9.1 17.0 12.0 13.1 ? 4.5 14925Id 11.4 8.4 14.5 10.9 12.3 5.3 4.1 149251e 10.7 8.1 14.0 10.7 11.4 4.6 2.9 14925If 9.3 8.1 13.0 10.9 11.4 4.8 3.3 149251g 8.6 6.8 13.5 9.5 10.8 5.0 3.3 149251h 9.7 6.5 13.5 4.4 7.1 4.4 3.4 149251i 8.9 6.8 11.5 8.0 9.0 3.4 2.4 149251J 7.6 6.9 9.0 6.4 8.4 2.8 2.3 149251k 6.7 6.1 7.0 6.4 8.1 2.3 2.0 149251-1 11.7 9.0 21.0 11.3 13.2 7.7 6.0 124133b 13.6 10.2 ? 10.4? 15.9 7.0 6.3 (holotype) Stratigraphic Occurrence.—Bone Spring For- mation, Skinner Ranch Formation (Decie Ranch, Poplar Tank, Dugout Mountain, and Sullivan Peak members), Cathedral Mountain Formation. Localities.—Bone Spring: AMNH 492, 591, 696. Decie Ranch: USNM 707a, 707g. Poplar Tank: USNM 707ha, 708e. Dugout Mountain: 700o, 700t, 732e, 733-1. Sullivan Peak: USNM 707b, 707d, 718z, 722h, 722-1, 727a. Skinner Ranch (lower): USNM 71 Id, 712p, 720f. Skinner Ranch (upper): USNM 705r, 709, 709a, 709z, 710r, 71 lz, 723-1. Skinner Ranch: USNM 727m, 730s. Cathedral Mountain: AMNH 500A, 500C, 500J, 500L, 500M, 504; USNM 702, 702a, 702b, 702ent, 702-low, 702un, 703b, 710d,711q, 714w, 721u, 723u, 723y, 726o, 726u, 726x, 726y, 727x, 731t, 733m, 735b. Diagnosis.—Strongly costellate Chonosteges of medium to large size with stout anchor spines and curved pipes or rarely funnels on the margin of the brachial valve. Types.—Holotype: USNM 124133b. Figured par- atypes: USNM 123901; 123902; 124131a; 124132a, b; 149251; 149259a, b; 154153b, c; 154154a, c-d, g-i; 154155; 154158a, b; 154384; 154385. Measured para- types: USNM 149251a-l; 149252a, b; 149257a-c; 149259a-d. Unfigured paratypes: USNM 123903c; 124131b; 154163a; 154154b, e, f. Figured specimens: USNM 149264; 154159a, b; 154160; 154161. Comparison.—This species is variable in all re- spects, in outline as well as in costation. Some specimens appear to conform fairly well to C. cos- tellata, new species, but the majority have stronger costellae than that species. The strong costellae dis- tinguish this species from all others described here. Along with the strong costae go the stout and thick anchor spines that spring from them and form the row around the anterior margin of the pedicle valve. Discussion.—A feature still more striking than the coarse costellae is the bent tubes around the anterior margin of the brachial valve. This is the only species in which these have been seen. They contrast strongly with the erect funnels of C. multi- costatus, and C. pulcher, both new species. Several specimens of C. variabilis also have erect funnels but, even allowing for difficulties in preservation and recovery from siliceous residues, they are very NUMBER 19 871 rare. The specimens with funnels come from the same blocks taken at USNM 702un that produced the numerous individuals with curved tubes. A specimen with bent tubes was taken also from the Skinner Ranch Formation (USNM 711). The Skinner Ranch Formation has yielded speci- mens of Chonosteges but none abundant. The re- sult is that most of the specimens are here referred to C. variabilis although some of them seem atypical. They are generally more strongly costellate than the other species and seem to fit into the variable C. variabilis. Larger collections may ultimately crys- tallize the few differences and make it possible to identify other species from these lower stratigraphie horizons. Subfamily INSTITELLINAE Muir-Wood and Cooper, 1960 Aulostegidae having trails forming a large an- terior gutter, with tonguelike extension in the ped- icle valve. Ornament costellate and visceral disc reticulate. Brachial valve without spines. Genera in West Texas: Institella Cooper, 1942; Glyptosteges, new genus; Craspedona, new genus. Institella makes a zone across the mountain and marks the base of the Cathedral Mountain Forma- tion. We did not find the genus outside this forma- tion. It is known however in the Caucasus and in the Sosio Formation of Sicily. Glyptosteges characterizes the Skinner Ranch Formation, especially the Dugout Mountain Mem- ber (Second Limestone Member of the Leonard Formation of P. B. King). It is not common any- where and is difficult to obtain because of its fragile shell. Its habit of attachment was like that of Institella. Genus Institella Cooper, 1942 Institella Cooper, 1942:230.—Muir-Wood and Cooper, 1960: 117.—Williams et al., 1965:H458. Subrectangular outline, convex pedicle valve, but nearly flat to gently concave brachial valve; an- terior commissure strongly folded toward brachial valve; pedicle valve deeply and narrowly sulcate; both valves provided with elaborate frill directed ventrad; surface of both valves costellate; surface of visceral disc area fairly regularly concentrically wrinkled to produce reticulate pattern suggesting. dictyoclostids. Rhizoid spines long and stout, located on ears, posterior margin, and umbo; orna- ment spines rare; brachial valve without spines. Pedicle valve with short interarea, no elytridium; margin of visceral region sharply keeled; diductor scars flabellate; diductor field narrowly elevated on ridge formed by exterior sulcus; inner adductor scars long and narrow, outer scars small, dendritic. Brachial valve with prominent lateral ridges, sessile cardinal process, and delicate, elevated brevi- septum; adductor field small, moderately elevated with inner scars smooth but outer scars dendritic. Type-Species.—Productus leonardensis R. E. King (1931: 70, pi. 14: figs. 4-9). Diagnosis.—Costellate-reticulate, frilled Aulos- tegidae having strongly uniplicate anterior commis- sure. Type-Specimen.—King did not name a holotype but mentions his figure 5 as a cotype. In his list of localities from which this species was taken he uses the word "types" after locality 120. He also gives the same locality for three of the measured speci- mens. Presumably he regarded the specimens from this place as typical of his species. Unfortunately he figured only one of them; it appears to be incom- plete and is illustrated from the side only. This specimen (YPM 10706) is therefore chosen as lectotype of the species. Comparison.—The only genus having external similarity to Institella is Sinualella from the Missis- sippian of Great Britian. The British genus is not provided with the elaborate flange of the Permian genus and the interior details of both valves are different. The Mississippian genus in the pedicle valve has a strongly impressed muscle-area having the shape and strength of muscle impressions dif- ferent from those of Institella. Inside the brachial valve the lateral ridges of Sinuatella are not so prominent and the outer adductor scars are not dendritic. Externally, Institella is similar to Cras- pedona but differs in exterior and interior details, as related under Craspedona. Discussion.—Many features of Institella, such as its leptaenoid form, obscure its relationship to the Aulostegidae. In spite of this the collection includes many specimens showing the members of this genus to have been attached and to have had the living habits of the Aulostegidae. Exterior.—The exterior of this genus is unusual for its ornament, and for the fold, sulcus, and frill. 872 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY The ornament is unusually strong for a member of the Aulostegidae and the reticulation of the visceral region suggests relationship to the Dictyoclostidae. Aulostegid characteristics are too strong, however, to permit classification with that group. It is a clear case of duplication of ornamentational features in unrelated stocks, a phenomenon that helps to cloud brachiopod systemmatics. In most productids the fold and sulcus are not well developed. In Institella, however, the sulcus is so deep and narrow that it divides the pedicle valve into two halves and the crease on the outside is re- flected on the inside as a high and effective median ridge. Anteriorly, the sulcus appears at the anterior end of the pedicle valve as a narrow trough in the frill, almost a tube in extreme cases. The sulcus originates on the umbo of the pedicle valve and deepens anteriorly to the front margin. On the brachial valve the fold is correspondingly well developed. The umbonal region forms a deep, nearly circular pit. At the anterior end of this pit the fold originates as a low ridge which elevates anteriorly and in most specimens is fairly strongly carínate. At the anterior end in well-preserved specimens the fold is also prolonged into a tubular arrangement fitting closely over that of the opposite valve. Usually this is broken away and the fold pro- duces an angular notch at the anterior end. The lateral and anterior frills are the most char- acteristic feature of this peculiar genus. They are well developed on both valves but are usually best preserved on the pedicle valve. In well-preserved specimens the frill grows abruptly in a ventral di- rection at an extremely small angle. It grows ven- trally to a plane almost level with the surface of the median swollen flanks of the pedicle valve. It then flattens and grows laterally for a considerable dis- tance to form a broad expansion. In the older speci- mens it then changes growth direction to dorsal and forms a gutter around the inside of the frill. Thus the body of the shell is surrounded by a deep moat produced by the frill, and the interior is surrounded by a gutter formed of the inside of the frill and bounded by its dorsally growing rim. At the anterior end of the valve, where the sulcus meets the margin, the frill is narrowly folded anteroventrally to form a deep trough or half-tube. When viewed from the inner side, this forms a carínate ridge or apex to the frill. The boundary between the interior and the lateral slope of the frill is almost knife-edge sharp. A frill closely fitting into the one of the pedicle valve is formed by the opposite valve. This one does not always match the other in develop- ment especially at the anterior end. These deep gutters on each side of the valve are undoubtedly devices to help channel the incoming water currents in feeding. These probably ran along the steep sides of the pedicle valve gutter and entered near the ears. The semitubular anterior end probably served as the outlet for waste-bearing currents. Spines.—As in most of the Aulostegidae two types of spines appear on Institella but an unusual feature of the genus is the poor development of ornament spines. These appear rarely on the visceral disc region and are given off from the points, or nodes, formed by intersection of the concentric wrinkles and the costellae. No specimen in the collection preserves these well enough to show their true length. The bases are small and it is therefore sup- posed that the spines were short. The rhizoid spines are strong and are confined to the ears, umbo, the posterior margin, and the frill to about midvalve. In the very young, rhizoid spines appear on the umbonal slopes as well. Some large specimens have rhizoid spines 4 to 5 inches long. These weave along the various surfaces of attach- ment and must have made strong and effective anchors. Some of the spines, however, were of no advantage to their owner. In one instance a spine extends from the posterior line for a half inch then turns abruptly onto itself, where it cements to its own visceral disc surface and runs along it for a considerable distance, affording no support or an- choring. Pedicle Valve Interior.—The interarea of In- stitella is usually short and the delthyrium open. In some specimens the same type of concave plate appears in the apex of the delthyrium as that seen in Limbella. This is a small concave callosity which serves as a socket in which the lophidium of the cardinal process revolves. The diductor scars of Institella are broad and flabellate, occupying about the posterior half of the valve on each side of the carínate median ele- vation formed by the sulcus. The adductor field is long and slender, and the median scars are perched on the crest of the median ridge. These are long and slender, with evidence of another lateral lobe, sug- gesting a form like that of Edriosteges. Posterior and posterolateral to these muscles is a pair of NUMBER 19 873 strongly dendritic scars. In large, old specimens the anterior set becomes dendritic. Brachial Valve Interior.—The cardinal pro- cess is the most important interior feature of Institella. It is typically aulostegid in being a tent-shaped structure with deep pit facing ventrad. Unlike Edriosteges, Limbella, and Echinosteges it is rather flat apically. The small Institella, about 5 mm long, is deeply concave, especially in the pos- teromedian region. Specimens about 8 mm in length are less concave but the posterior region is nevertheless fairly swollen. In specimens of this size the cardinal process is still deeply excavated, and the thickening elongate adductor tracks form a groove leading into the cardinal process antron. Filling of the antron has already started in speci- mens 12 to 13 mm in length. In specimens 15 to 20 mm long the antron is nearly or completely filled. In most larger and thicker specimens the antron has completely disappeared. In some specimens the two prongs so characteristc of Edriosteges and Echinosteges are present, although generally rare. The shaft of the cardinal process of Institella is so short as to appear nonexistent in old specimens. Furthermore, the bowed lateral ridges join the sides of the cardinal process so intimately that the two structures appear as one. The myophore of the cardinal process shows the same variations as in other aulostegid genera, some specimens having a widely bilobed process, others are tightly trilobed, and still others are widely trilobed. In young speci- mens the myophore is generally bilobed when viewed from the ventral side and either bilobed or trilobed in posterior view. The lophidium of the cardinal process is always prominent and strongly carínate. It forms the sole closure to the delthyrium. Variation in the cardinal processes of Institella appears to be completely random, as in other aulo- stegid genera. Small specimens may exhibit com- pletely adult characters, while others of larger size still preserve juvenile features. The brachial ridges in this genus are somewhat better preserved than in Echinosteges, Edriosteges, and Limbella. The ridge starts between the smooth and dendritic diductors, then slopes anterolater- ally to make a narrow loop on the swollen flank. The adductor field is somewhat elongated and consists of an anterior or inner pair of scars, each scar lobed, with the larger one inside flanking the breviseptum and the smaller one on the outside. These are flanked on the outside and postero- lateral to the inner pair by a dendritic pair of scars. The pattern is thus like that of Edriosteges and re- lated genera. Stratigraphic Occurrence.—Institella is a com- mon genus only in the Glass Mountains and is here restricted to a certain part, the Cathedral Mountain Formation. It is rare in the western part of the mountains, where it occurs in abundance only in the Wedin Member of the Cathedral Mountain Formation. In the eastern part of the mountains it is common in the vicinity of Split Tank but is rarer elsewhere. Institella, in our experience, appears first in the thin limestone interbedded with yellow shales at the very crest of Leonard Mountain. Although it has been reported outside of these levels, we have not collected it from any other horizons. Elsewhere in the United States the genus occurs in the middle part of the Cibolo limestone in the Chinati Mountains at the narrows of Cibolo Creek and in the upper part of the Bone Spring Formation and Victorio Peak Member. Outside the United States Licharew (1937:58) assigned to Sinuatella his species Productus sub- sinuatus, but the strong folding, large frill and fine, reticulate ornament suggest Institella. These specimens come from the Pb2 level of the Permian in the North Caucasus. Two species are also known from the Sosio beds of Sicily. Productus salomonensis Gemmellaro (1892: 26) (USNM 149167) is a large species suggestive of /. leonardensis (King) but has a less angular sul- cus, more ornament spines, and finer ornamenta- tion. Another species (USNM 149165, 149166), not named so far as we know, is smaller, more strongly ornamented, and has a shallower and narrower sulcus than /. salomonensis. Institella leonardensis (R. E. King) Plate 246: figures 6-14; Plate 247: figures 1-31; Plate 248: figures 1-38; Plate 463: figures 1-4; Plate 468: figure 10 Producías leonardensis R. E. King, 1931:70, pi. 14: figs. 4-9.— Cooper in Shinier and Slirock, 1944:351, pi. 138: figs. 3-5. Institella leonardensis (R. E. King) Muir-Wood and Cooper, 1960:117, pi. 22: figs. 1-15. 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Localities.—Cathedral Mountain: USNM 703b. Road Canyon: AMNH 503, 507; USNM 702c, 703, 703a, 703c, 703d, 708c, 716x, 719x, 721s, 721t, 721y, 726f, 726z, 726za, 732m. Diagnosis.—Large, generally wide Cyclacaniha- ria with large apical angle and few protective spines around the inside margin of the cup. Types.—Holotype: USNM 151766t. Figured paratypes: USNM 151765a-e; 151766a, b, q; 154060a, b; 154061 a-c, e; 154062a, b; 154065. Mea- sured paratypes: USNM 151766a-s, u; 151768a-k. Unfigured paratypes: USNM 151766c-p, r, s, u; 154061d. Comparisons.—In highly variable shells, espe- cially those in which the variation is induced by inhospitable living conditions, specimens of each species will strongly resemble certain types of variants of the others. This species has individuals strongly resembling some of the variants of C. kingorum Cooper and Grant and C. robusta, new species, but the average of each species is quite unlike the average of the others. Cyclacaniharia paucispinosa differs from C. kingorum in the lesser development of the protective spines around the inner margin of the cup, in the larger apical angle, and in the generally wider and more circular cup. The apical angle of the Road Canyon species is not greatly different from that of C. robusta, but the difference in the degree of development of the protective spines is strong. The brachial valves of C. paucispinosa are not internally nodose as in C. robusta, the development of the muscle mound is much less, and C. paucispinosa has few internal spine tubes. Discussion.—Shells of this species are very dis- tinctive, with their generally wide cups, thin shell, few spines, and often somewhat nude appearing exterior. Generally they are thinner than those of the other species of Cyclacaniharia. This is especially true of specimens from USNM 702c which have almost paper-thin margins to the vestibule especially in young adults. In many specimens the mouth is very wide and expanded rather than contracted as in many specimens of C. kingorum. The spines on the inner rim of the cup are generally somewhat scattered, usually varying from delicate to moder- ately stout, but seldom ponderous and like stag- horns in C. kingorum and C. robusta. Furthermore, the largest spine seen measures about 11 mm. Inas- much as the spines generally are directed at an angle to the cup margin and thus project obliquely rather than directly across the orifice, they do not cover the opening of the cup as they do in C. kingorum and C. robusta. The rhizoid spines of this species appear to be generally located below (ventrad) the aulacoterma and thus leave a fair portion of the cup nude. This fact, together with the smooth unwrinkled character of some of the specimens, lends a rather bare appearance to the cups. These two characters give the species a readily recognizable appearance. The interior of the pedicle valve is distinctive, compared to that of C. kingorum and C. robusta, having some features varying from these species. Most specimens of the pedicle valve are long, and fairly thin-shelled, and do not have a strong apical thickening. A few that have grown crowded between their bretheren, however, are elongated and have a thick, cystose apex. Inside, the muscle mound is seldom thickly developed, and the plates comprising it are usually long and flat. In some, the mound has a double-ridged crest, but other evidence of the muscle scars was not observed. A striking difference between this species and the two large forms from the Word Formation is the poor development of the tubes on the inner shell wall. These, when present, are generally few and scattered and appear just dorsad to the distal end of the muscle mound. None were seen occupying the upper or dorsad portions of the living chamber. In some specimens the ends of the tubes extend into the body chamber and are free of the wall, rather than prone as in the Word species. The interior of the brachial valve is characterized by a large and well-formed cardinal process but only a few endospines are arranged in a single row just inside the anterior margin. Another unusual feature is the fairly well marked presence of the brevisep- tum which is usually not clearly seen in the Word species. Large specimens have well-thickened and strongly dendritic adductor scars. Cyclacantharia robusta, new species Plate 295: figures 7-13; Plate 297: figures 9-19; Plate 302: figures 1-32 Large variable cones with apical angle varying from 30° to 54°, averaging about 45°, apex pointed 950 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOG to bluntly rounded; aperture in adults with moderate flare; vestibule moderately deep; body cavity is 0.7 of height. Cross section at aulacoterma almost circular (length/width ratio is 0.90). Pos- terior side slightly flattened; anterior side broadly rounded and sides rounded. Protective spines on anterior strong and well branched, often thick; spines on posterior side in adult specimens usually large, occasionally massive. Rhizoid spines long and stout. Surface with strong concentric wrinkles. Brachial valve flat to moderately concave in larger specimens with short necks and broadly rounded sides; anterior margin gently rounded t< nearly straight. Surface usually smooth in adults Pedicle valve interior with strong shelflike aula coterma; pseudodeltidial area facing interior, wid< and deeply grooved. Muscle field with strong moundlike adductor field and moderately deer, diductor impressions. Mound with single or doublt ridge on crest. Interior spine tubes numerous or entire interior except in pseudodeltidial region. Brachial valve interior with strong lateral ridges; large cardinal process, slight breviseptum, and few large, stout endospines. Measurements (in mm).— brachial brachial apical valve valve surface hinge thick- aperture aperture flange angle length length width length width midwidth height ness length width length USNM 728 151646a 54° 30.2 17.0 27.0 49.0 9.3 33.6 49.2 34.4 36.0 46.5 8.0 151646b 49° 34.7 23.0 26.5 45.0 8.5 35.2 43.2 33.3 36.0 42.7 7.0 (holotype) 151646c 54° 25.8 16.0 24.0 36.0 7.3 31.4 33.0 21.9 33.2 36.9 11.0 151646d 43° 21.4 16.0? 45.0 23.0 ? 28.2 42.3 28.0? 25.3 31.4? 7.0 151646e 24° 18.6 11.0 16.0 43.0? 7.5 19.3 45.0 34.0 18.6 21.4 ? 151646f 38° 22.9 21.0 21.2 46.0 6.3 24.2 43.0 28.5 32.0 29.1 ? 151646g 38° 22.3 15.0? 21.5 42.0 6.5 26.6 42.4 29.0 26.5 34.6 9.6 151646h 43° 28.2 22.5 26.5 52.0 5.8 31.4 39.6 24.3 28.3? 34.0 6.0 151646Í 49° 24.6 17.0 26.0 45.0 9.0 30.4 40.0 28.0 22.6 35.7 4.0 151646J 50° 23.4 16.5 25.0 30.0 7.0 27.8 26.0 17.5 28.0 32.5 ? 151646k 37° 20.6 14.0 38.0 16.0 6.0 21.8 31.0 21.0 22.6 25.0 5.0 1516461 48° 16.6 13.5 17.5 31.0 5.5 19.6 20.4 12.0 22.7 26.9 ? 151646m 38° 14.0 11.0 14.0 20.0 4.0 16.0 19.0 14.6 15.3 18.0? ? 151646n ? 7.7 6.0 7.0 10.0 2.5 7.7 6.4 5.2 8.9 9.7 ? 151646o 52° 36.3 ? ? 47.0 ? 36.0 48.0 36.8? 35.3? 45.0? ? Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Limestone Member). Localities.—AMNH 496, 512 (= USNM 728), 600. Diagnosis.—Large, stout Cyclacantharia having an average apical angle of about 45° and stout protective spines around the cup rim in adults. Types.—Holotype: USNM 151646b. Figured paratypes: USNM 151645a, b; 151646a, e, g, j; 154059a-g, i-p, r-u. Measured paratypes: USNM 151646a, c-o. Unfigured paratypes: USNM 151646c, d, f, h, i; 154059h, q. Comparison.—This species is most like C. kingo- rum Cooper and Grant and shares some features with it. The relationship of the height to the body cavity is the same as that of C. kingorum and the ratio of height to width is most like that of C. kingorum from the Word Formation (China Tank Member, USNM 706c) rather than like the more typical forms such as those at USNM 706e. The apical angle averages higher than normal in C. kingorum and the adults attain a length of 50 mm, but none have been found which attain a length equal to those at USNM 706e in the Glass Moun- tains. The protective spines of C. robusta are very large and massive, covering the large aperture, and the spines on the posterior side on the hood are generally more massive and longer than those of C. kingorum. Cyclacantharia roubsta can be distinguished readily from C. paucispinosa, new species, by the bare appearance of the exterior of the latter, its generally greater apical angle, the smaller and less robust protective spines, and the generally lesser NUMBER 19 951 development of the muscle mound in the apex of the pedicle valve. The brachial valves of the two are also unlike, because C. robusta has a stronger development of endospines but the adductor scars are not so strongly thickened and dendritic as in C. paucispinosa. Discussion.—This species has no features not seen on other richthofeniids but it has some of them exceptionally developed, such as the interior tubes on the body wall, the pedicle valve muscle field, the protective spines, rhizoid spines, aula- coterma, and the shell. The body wall of many specimens between the apex and the aulacoterma is covered by longitudi- nal tubes. These are strongest posteriorly and dis- appear into the shell wall at various places to emerge on the exterior as a rhizoid spine, some of considerable length. The passage of the spines through the cystose layer and outer shell wall can be seen in numerous specimens. Sections near the base of the cup show spines within the cystose layer of the muscle mound and at any other part except the pseudodeltidial region. The cysts cling to the outside of the tube and effectively cover it. In some, the tubes are superimposed on one another, a short one extending into the cystose layer and at the place where it passes into that layer, and a new tube begins with an opening at about the end of the previous tube. This gives some of the tubes the appearance of having one or more openings. The tubes do not appear until a fairly late stage in development, early adulthood. These tubes appear to be identical to those developed in many productid genera, such as Liosotella, which appear on the inner lateral slopes anterior to the ear baffle, and W aagenoconcha as described by Grant (1966b). Some specimens of Cyclacantharia robusta show actual scars of the muscles. The diductor scars thus appear to lie on the sloping faces of the muscle mounds in the apex. The muscle mounds are built of cystose shell, the cysts being large blisters. The later ones formed on the outside of the mound facing the aperture are somewhat conical in form. The adductors appear to have been attached to one or two linear ridges that lie on the crest of the mound. At a fairly early stage in the development, protective spines form in the granular zone around the inside of the vestibule, above the aulacoterma. Several rows of them form as small knobs and gradually lengthen with age. In late stages of shell growth the posterior side produces cysts around old spines as the animal migrates in a dorsal direction in its shell. Many of the cysts bear small spines that appear to be incipient protective spines. These resemble taleolae very strongly, and it is possible that the spines are a modification and elaboration of taleolae. The granules around the inner vestibule are taleolae, and evidence points to their presence on the layer lining the wall of the body cavity. Broken protective spines have a radial or stellate structure in the interior and there also is a different color between the main shell substance of the spine and the radial structures, the latter appearing as a white star in some of the specimens that are broken across. A central axis makes a round hub for the wheel from which seven spokes radiate. On the exterior the spokes stand up as elevated lines, thus producing a striated appearance. The spokes appear to be harder or more resistant than the matrix between them, thus emphasizing the ribbed appear- ance of the spine (USNM 151646 h, j). Because of their silicified state, it is difficult to make any state- ment regarding the nature of the two elements making up these spines, nor does the collection include any unsilicified material that could be sectioned. Several specimens have the rhizoid spines well enough preserved to show some of their character- istics. These spines generally are simple tubes but, where passing over obstructions are often flattened or otherwise distorted. In other places they swell to double or more their normal size. Many of them flatten and widen on making contact with substrate, spreading out distally and thus effecting a stronger hold on the bottom. In some instances spines coalesce where their ends meet, but no example of branching was seen. Although the spines are effec- tive holdfasts, they also serve in the economy of space in the sea as dwelling sites for innumerable small invertebrates, and for the spat of Cyclacan- tharia. The spines of some also became traps for small shells that were killed when ultimately their brachial valves could not be moved, so the shells could not grow normally (see pi. 292: figs. 1, 2; pi. 116: fig. 8). The aulacoterma of adults is usually thick and forms a prominent ridge around the inside of the shell at the dorsal end of the body cavity. Broken specimens that show the whole interior of the body 952 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY cavity commonly exhibit a succession of rings around the body wall representing several genera- tions of aulacoterma. The distance between these shows the extent of growth of the shell during certain periods, but it is not possible to determine how long each period was. Most stages of growth are preserved in specimens of this species. They exhibit the same types of variation seen in C. kingorum but few subcylindri- cal forms were developed, suggesting that C. robusta was not so crowded in its early stages as C. kingo- rum. Cyclacantharia transitoria, new species Plate 294: figures 19-33 Medium to fairly large variable cones, apical angle varying between 25° and 75°, averaging about 45°. Cross section at aulacoterma roundly elliptical, cup slightly flattened on posterior side; cup usually high, but depends on position in colony. Apex of high slender specimens considerably thickened by cystose shell, those with broad apical angle less so. Body chamber occupying about two-thirds of height. Aperture with slight to moderate flare. Protective spines forming complete ring in old adults, with thick and erect spines on hood, but these sporadic in young adults. Protective spines usually short and stout. Rhizoid spines not numerous, slender to moderately thick. Pedicle valve interior with thick aulacoterma and entire interior thickened in adults, strong antero- median ridge in many specimens. Psuedodeltidial area fairly wide, with moderately strongly rounded margins; muscle mound low, slightly thickened, not greatly elongated. Internal spines rare. Postero- lateral platforms small and narrow. Brachial valve flat posteriorly but gently concave, anterior reflected dorsally in anterior third. Neck short, reentrant not deep; shoulders sloping and sides anteriorly narrowly crowded. Brachial value interior with large and thickened, often elongated cardinal process in old specimens; adductor scars thickened, anteromedian scars smaller than posterior pair. Breviseptum strong in some specimens; endospines stout, bordering an- terior margin. Myophragm low, double ridge, chili- dium strongly developed. Measurements (in mm).— brachial brachial apical valve valve surface hinge thick- aperture aperture angle length length width length ividth midwidth height ness length width USNM 721z 152690a 45° 17.2 ? ? 39.0 ? 21.6 32.8 ? 12.6 17.5 152690b 65° 24.0 ? } 32.0 ? 29.1 25.4 ? 20.3 25.9 152690c 42° 19.6 13.0 20.6 33.0 ? 24.3 27.4 21.0 16.0 22.0 152690d 62° 20.9 ? ? 26.0 ? 23.9 18.0 ? 18.5 22.8 USNM 726d 152693a 45° 24.4 ? ? 38.0 7.0 31.6 35.5 ? 13.4 21.4 152693b 30° 24.0 11.3 14.0 37.5 4.8 23.3 29.9 20.6 13.3 17.3 USNM 724c 152691a 45° 20.8 13.2 16.3 32.0? 6.0 23.4 28.2 18.8 16.2 19.4 152691b 55° 20.7 14.5 16.3 36.0 6.0 24.4 27.8 18.5 16.6 22.6 (holotypc) 152691c 58° 16.4 ? ? 32.0 5.2 19.6 16.2 ? 13.0 16.8 USNM 721j 152692a 34° 19.4 14.5 17.3 35.0 + 7.3 23.5 32.0? 22.5 17.5 21.3 USNM 710u 151654a 47° 19.8 13.5 22.2 40.0 8.0? 27.4 36.6 22.9 22.7 27.8? 151654b 75o? 21.5 14.0 21.5 33.0 7.3 25.9 35.0 23.0 29.7 ? 151654c 39° 21.4 15.5 17.5 33.0 8.5 20.5 28.7 18.0 27.3 25.0 151654d 38° 18.4 12.0 20.0 38.0 5.0? 21.2 32.3 23.4 19.7 25.3 151654e 32° 16.9 13.2 14.0 44.0 ? 18.0 43.7 24.0 22.4 ? 151654Í 31° 13.3 11.0? 13.0? 31.0 ? 16.0 25.6 ? ? ? 151654g 37° 12.0 10.3 14.8 21.0 5.0 15.9 26.3 18.2 14.8 18.0 151654h 37° 13.0 9.5 13.0 20.0 4.8 12.8 18.0 11.0 14.3 15.0? NUMBER 19 953 Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—AMNH 503; USNM 700v, 706f, 707e, 710u, 713, 716xa, 720d, 721], 721r, 721w, 721x, 721y, 721z, 722e, 723x, 724a, 724b, 724c, 724j, 726d, 726e, 732i, 732j, 736x. Diagnosis.—Medium sized Cyclacantharia with moderate apical angle and development of protec- tive spines spasmodic on the posterior side. Types.—Holotype: USNM 152691b. Figured paratypes: USNM 152691a, c; 152692a; 152693b. Measured paratypes: USNM 151654a-h; 152690a-d; 152691a, c; 152692a; 152693a, b. Unfigured para- type: USNM 152693a. Comparison.—This species more nearly suggests C. kingorum Cooper and Grant than any of the other species of this genus. It differs in a lesser development of protective spines on the posterior side of the cup and a generally smaller size. Fewer internal spines appear in C. transitoria than in C. kingorum. Discussion.—This species is not as abundant as C. kingorum, and it has therefore been impossible to define its characters as well as those of the Word species. Brachial valves from USNM 71 Ou have a very obese cardinal process and an unusually large development of the breviseptum. Furthermore, the chilidium is very well developed in this species. The cardinal process in some specimens has the lobes greatly elongated anteriorly. This character- istic is strongly reminiscent of a similar process in the aulostegids. Cyclacantharia species 1 Variable but usually long and slender cones with long cystose apex; apical angle small, varying be- tween 20° and 40°. Cystose part occupying about one-third of height. Cross section variable, generally elliptical. Body chamber greatly elongated. Aper- ture generally not flared. Protective spines not seen; rhizoid spines not preserved. Pedicle valve interior with very narrow pseudo- deltidium; pseudodeltidial area covered only api- cally; muscle mound not strongly developed. Brachial valve moderately long necked; shoulders narrowly rounded. Interior not known. Described and measured specimen: USNM 152689. Measurements (in mm).—From locality USNM 720e, specimen 152689: apical angle 38°, length 21.6, surface length 47.0, midwidth 27.5, height 48.5 + - Stratigraphic Occurrence.—Skinner Ranch Formation (base). Locality.—USNM 720e. Diagnosis.—Elongate cones with high body cham- bers, low muscle mound, and narrow pseudodel- tidium. Comparison.—This species is more slender than other described Cyclacantharia. It resembles the higher specimens of Hercosia uddeni which R. E. King described as Prorichlhofenia likharewi, but the latter has a strong apical septum and not so high a body chamber. Discussion.—This species occurs scattered among the Scacchinella and other bioherms that are abun- dant at USNM 720e. It forms small clusters and patches of very closely attached individuals. This very intimate growth evidently accounts for the ex- tremely high cups that are so characteristic. Cyclacantharia species unidentifiable Several small lots of Cyclacantharia are impossi- ble to place in the species described above. Some of these are undoubtedly new species but considerably more material would be needed to demonstrate this. The specimens are listed by locality. Species 2 (USNM 728f).—This locality includes specimens similar to fragmentary ones from AMNH 628, 629, and 631, which are from the same strati- graphic level in the Bone Spring Formation and very close to USNM 728e. The specimens are all fairly erect cups with a fairly deep body chamber and therefore not referable to Acritosia. In most of the specimens the posterior side is not well pre- served but in one of them (AMNH 631), an obese specimen preserving only the posterior side, thick spines overhang the hinge. Described specimens: USNM 155032. Species 3 (USNM 746).—Several specimens have the cup short, with wide aperture and large apical angle. The specimens do not have a median septum and the hood of the posterior side is not preserved on any of them. Described specimens: USNM 151635. Species 4 (USNM 702d).—A small single cup attached to a bryozoan branch has a complete circle of delicate spines around the inside of the aperture. 954 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY The specimen is only 11 mm in height, but the complete circle of protective spines suggests an adult. Figured specimen (PI. 294; figs. 17, 18): USNM 154053. Species 5 (AMNH 404).—A fine specimen about 30 mm high and with a nearly circular cup is a definite Cyclacantharia because it has a complete circle of spines around the inside of the cup. The spines are short and thin but occupy a zone of at least 5 mm. Figured specimen (PI. 308: figs. 7-9): USNM 151641. Species 6 (AMNH 417).—This lot consists of 20 specimens of assorted sizes. The adult is a high cup (30 mm or more) with elliptical aperture. The shell is stout; the muscle region of the pedicle valve is thickened and generally surrounded by numerous interior spines. Spines appear around the inside of the cup but are small on the posterior side. The brachial valve has stout but subdued en- dospines and an obscure breviseptum. The stratigraphie occurrence of this lot is doubt- fully quoted as Carlsbad Limestone. If this is the correct horizon, the range of the genus into the Capitan-Carlsbad is established. Described specimens: USNM 151642. Taphrosestria, new genus [Greek taphros (ditch) + sestron (sieve)] Small, squat, irregular cones with rounded base and wide flaring aperture. Brachial valve forming lip deep within cone, surmounted by high vestibule. Inner marginal wall of anterior side with flat anas- tomosing spines, commonly united closely and ex- tending nearly across aperture, leaving narrow channel on posterior side; lip of cone sulcate on posterior wall of cup. Hood large, thickened and cystose. Exterior strongly rugose and squamose, squamae formed by successive margins of apera- ture (cone-in-cone structure). Anchor spines round and stout. Pedicle valve interior with palintrope; aulaco- terma strong and thick. Apex thickened by triangu- lar muscle area; diductor scars outside adductors, triangular, attached to fluted plate overhanging lateral cavities. Adductor field thick and solid, slightly elevated above diductors. Adductors elon- gate, consisting of anterior and posterior pairs. Me- dian myophragm small. Pseudodeltidial area short, open to interior. Internal spines large, short, nu- merous. Brachial valve coarsely granulóse to spinose on exterior; interior with strong, fairly erect but bilobed, short-shafted cardinal process. Region be- tween cardinal process and adductor field thick- ened; median buttress ridge double, but indistinct. Adductor scars moderately thickened, consisting of inner anterior pair and outer posterior pair. Bra- chial ridges, when preserved, extending obliquely anterolaterally; endospines marginal, reduced. Breviseptum reduced and indistinct. Type-Species.—Taphrosestria peculiaris, new species. Diagnosis.—Cyclacanthariidae with specialized protective spines, thickened muscle area in the pedicle valve, and extended pseudodeltidial region. Comparisons.—The small size and squat appear- ance of these cones resemble Teguliferina Schu- chert and Le Vene and Acritosia Cooper and Grant. Taphrosestria differs in the form of the protective spines and the circulation channel produced by them on the posterior side of the cup. It also differs from Teguliferina in not having the flattened anchor spines so characteristic of that genus and in having well-developed cystose tissue in the apex. It differs from Acritosia in the character of the pedicle muscle field, details of the brachial valve, and the greater development of the psudodeltidial region. Taphrosestria differs from Cyclacantharia in not having a complete ring of spines around the inside margin of the cup, although it agrees with it inter- nally. It also differs strongly from Hercosia, which it resembles externally, in not having the strong knife- edge median septum in the pedicle valve. Taphrosestria appears to be intermediate be- tween the Teguliferinidae which it resembles in its exterior form, and the Cylacanthariidae or Her- cosiidae in its cardinal process. Discussion.—This is one of the most peculiar of all the Glass Mountains brachiopods. Its squat form and spreading apertural margin combined with the nearly complete cover of flat anastomosing spines is distinctive. The form of the cup of Taphrosestria is variable, but the degree of variability seems not to be so great as in Hercosia, or in Hercosestria. Some specimens of Taphrosestria are low and spreading, but others form fairly erect cones. Generally the surface of NUMBER 19 955 attachment is irregular and fairly broad. The bases do not come to a point as in the more narrowly conical forms, consequently, it is difficult to measure an apical angle for specimens of Taphrosestria. The name was given in allusion to a well-marked groove on the posterior, or hood side, of the cup that is conspicuous in some specimens but not all of them. This small trough, often tubular, is located under the extremities of the anastomosing protective spines and thus probably formed an excurrent channel during feeding. The incoming channel in feeding would be through the spines. The protective spines are broad and flat and as they spread across the anterior side of the cup to- ward the posterior side they may unite and thus form a fairly solid network. The spines do not unite with the entire posterior side of the margin. Some of them attach to the inner sides of the cup margin and to the lateral parts of the posterior margin, but are left free over the posterior groove. In some specimens the anterior side of the aperture is cov- ered by a solid plate or roof for as much as a half of the aperture. This is caused by a solid sheet of shell material not differentiated into individual spines at its origin. In these examples individual spines form far out over the aperture, thus the aperture may be- come greatly restricted. Some details of the interior are as strange as those of the exterior. The aulacoterma of the pedicle valve is generally very thick and commonly is ele- vated medianly into a low median ridge that forms a notch in the anterior margin of the brachial valve. The pseudodeltidial area in its details is ex- actly like that of Teguliferina, but Taphrosestria differs in being extended dorsally to a modest de- gree as the shell grows. Therefore, on the inside of the posterior wall a pseudodeltidial area like that of the prorichthofeniids, only shorter, may be seen. Of considerable interest is the ventral muscle area which is better developed than in most related genera. Generally this area is fairly well elevated but it is commonly deeply excavated laterally so that the attachment parts of the diductor scars are thin plates, often elaborately fluted at their mar- gins. The median part, where the adductors are attached, is cemented solidly to the floor and the muscle scars, which were elongate, are separated by a low myophragm, not always clearly visible. Interior spines are present, even common in some of the specimens. They generally are of large di- ameter with large openings but they do not extend far along the inner valve surface. The shell walls of Taphrosestria are moderately thick but are strengthened in certain parts by the development of cystose shell. Broad flat cysts are laid down under the muscle field but the cysts, formed to strengthen the hood, are generally small and rounded. The exterior of the brachial valve is so coarsely papillose, or even spinose, that these valves can usually be distinguished from those of Cyclacan- tharia, which also occurs in these beds associated with Taphrosestria. The brachial valve is short- necked and has narrow, sloping shoulders and is thus quite unlike that of the preceding genera. In profile it is generally slightly convex. The cardinal process is short but is fairly erect and has large myophores. The shaft is double, so that the process appears to consist of two parts closely pressed together. Anterior to it the shell is nearly smooth, having been covered by adventitious shell and considerably thickened. Anterior to this part may be seen a remnant of the double median ridge which in many specimens divides the adduc- tor scars. The muscle field is well defined and the four scars of the adductors are usually clear, even in somewhat waterworn specimens. In other speci- mens the scars are greatly thickened and elevated. None of the brachial valves in the collection shows well-formed endospines. These usually appear as elevated lines or dashes, a few along the front mar- gin. This condition suggests that the spines became reduced as the protective spines over the aperture became more highly developed. One brachial valve of T. peculiaris shows the trace of the brachial ridges, a rare feature in any of these genera. These ridges are elongate, oblique, extending anterolaterally from the muscle field and nearly to the rounded anterolateral shell extremi- ties. Growth.—Few young specimens were obtained, but these indicate a manner of growth similar to that of the other richthofeniacean genera. Speci- men USNM 151760k is the youngest measured specimen that has attained a width of aperture of 12 mm, yet it has no trace of the spines on anterior side. The hood is well formed, however, and has attained a length of about 3 mm, while the body chamber is extremely shallow. 956 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Taphrosestria expansa, new species Plate 303: figures 12-33 Large for genus, squat conical form, widely expanded margin of aperture. Anterior side some- what less expanded than posterior side; apex flat- tened and fairly broad, cytose shell sparsely developed, strongest on posterior side and in apical region. Aperture widely flaring, with broad smooth inner surface; cone-in-cone effect moderately devel- oped. Protective spines long, frequently intergrown, flattened but leaving broad and large posterior channel. Rhizoid spines numerous, fairly stout. Pedicle valve interior with thick aulacoterma having median elevation on anterior side; muscle area thick and flabellate, muscle scars strongly impressed, not readily differentiated. Brachial valve nearly flat, distantly and coarsely papillose and spinose; spines short and stout; neck short; reentrant slight; interior with short bilobed cardinal process; breviseptum almost obsolete; adductor field thickened, brachial ridges not developed. Measurements (in mm).— brachial surface hinge thick- aperture aperture length valve length length width midwidth height ness length width USNM 724b 152688a 20.6 ? 26.0 ? 24.0 12.2 ? 10.6 15.5 152688b 30.0 11.6 25.0? 6.4 36.6 18.7? ? 11.2 17.5 152688c 24.3 } 23.0 ? 29.6 17.3 9.7? 10.8 19.0? 152688d 28.7 ? 30.0? ? 27.0 19.0 ? 10.5 17.6 152688e 31.0 ? 33.0? ? 34.0 20.0 ? 10.0 16.9 152688f 23.2 ? 30.0 6.5 36.6 17.0 ? 10.0 16.0 152688h 25.4 11.4 27.0 5.0 25.0 23.2 c.8.0 9.6 22.0 (holotype) Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USNM 721y, 724b. Diagnosis.—Large Taphrosestria with widely ex- panded and flaring aperture. Types.—Holotype: USNM 152688h. Figured paratypes: USNM 152688b, d-f; 154084. Measured paratypes: USNM 152688a-f. Unfigured paratypes: USNM 152688a, c, g. Comparison.—The large size and widely flaring aperture of this species is a ready distinction from T. peculiaris, new species. Discussion.—This species is uncommon but very distinctive. Except rarely, the spines do not grow so solidly together, as in the smaller species, and they are generally less massive in T. expansa than in T. peculiaris. Taphrosesiria expansa usually has a very ragged appearance because of the mode of formation of the flaring aperture. New margins or lips are added at different growth stages, and the earlier ones are usually not covered. In one speci- men the flaring lip was built over the spines in such a way that a large expanse of these spines appears between the old and the new lip. The younger spines are thicker than the older ones. The dorsal valve is small relative to the great expansion of the aperture. The cardinal process in this species is small and low, aulostegid in expres- sion, and posterodorsally covered by a chilidium. Taphrosestria peculiaris, new species Plate 303: ficures 1-10; Plate 304: figures 1-45; Plate 305: figures 1-20 Small, usually squat cones with strongly rugose exterior and small base of attachment. Anterior side generally slightly lower than opposite one. Posterior side generally flattened. Apical angle broad and generally rounded. Cystose material sparsely devel- oped. Aperture irregular, usually with widely flaring margin, successive apertural margins having strong "cone-in-cone" effect producing elaborately frilled exterior. Protective spines broad and flattened, anastomosing and spreading nearly across aperture to leave narrow channel on posterior side. Rhizoid spines numerous, rounded and fairly stout. NUMBER 19 957 Pedicle valve interior with broad aulacoterma, thickest posteriorly; muscle area broadly flabellate, with poorly to well developed median myophragm; diductor attachments subtriangular, elevated, and excavated below; commonly elevated above adduc- tors; adductor field broad, widely and longitudinally elliptical in outline; interarea well developed; pseudodeltidial region short, occasionally with slight growth track; interior spines short, numerous, and with wide diameter. Brachial valve slightly convex to flat, strongly and coarsely papillose to spinose. Neck short, reentrant slight; shoulders not well developed; sides narrowly rounded. Brachial valve interior with erect short-shafted, bilobed cardinal process with large myophores. Breviseptum short and inconspicuous; median ridge double but obscure; adductor scars thickened in some specimens; brachial ridges usually not clear but directed anterolaterally. Measurements (in mm).— brachial surface hinge thick- aperture aperture length valve length length width midwidth height ness length width USNM 710u 151760a 14.2 ? 13.0 16.4 15.0 ? 15.0 18.4 151760b •14.3 10.5 27.0 17.3 21.9 11.8 16.6 26.8 151760c 13.0 10.0? 25.0 4.0 12.4 20.5 9.8 10.0 16.0 151760d 10.4 ? 17.0 12.8 14.4 ? 18.8 20.4 151760e 10.2 8.0? 14.0 14.3 14.4 7.0? 14.2 17.5 151760f 12.5 9.0? 20.0 18.3 17.0 8.0? 15.4 19.7 151760g 10.7 8.0? 11.0 16.7 12.9 7.0? 17.8 22.5 151760h 10.3 ? 11.0 15.6 14.2 ? 16.0 18.0 151760Í 12.6 ? 10.0? 15.6 12.6 4.5? 14.8 18.0 151760J 10.0 7.0 5.0 3.3 13.3 6.8 4.7? 12.8 16.5 151760k 8.0 6.5 7.0 3.0 9.6 5.9 2.3 9.2 12.3 1517601 10.6 ? 6.5 11.0 11.0 4.7? 15.5 17.0 151760m 10.5 6.5? 13.0? 13.8 15.5 7.0? 20.2 22.4 151760n 10.6 8.0 17.0 4.0 12.0 14.2 8.0? 15.4 14.0 USNM 721y 154082a 16.5 ? 20.0 ? 16.6 18.2 10.0? 16.5 30.0 (holotype) Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USNM 707e, 709c, 710u, 716z, 721 j, 721t, 721w, 721x, 721y, 722f, 723x, 724a, 724b. Diagnosis.—Squat, squamose, and rugose, with body chamber occupying about half the height and thick muscle platform in pedicle valve. Types.—Holotype: USNM 154082a. Figured paratypes: USNM 151757a-d; 151759c-f; 151760a, d, H m-q; 154082b; 154085; 154086; 154087; 154109. Measured paratypes: USNM 151760a-n. Unfigured paratypes: USNM 151759a, b; 151760b, e, j-1. Comparison.—This species bears some resem- blance to Teguliferina compacta, new species, which is a thick-shelled, stout form differing from Taphrosestria, in having a more cylindrical cup, fewer spines covering the aperture, and a strong cone-in-cone effect. This species differs from Taph- rosestria expansa in having a smaller size and less flaring cone. Discussion.—The anastomosing nature of the protective spines and their complete spanning of the cup aperture is a unique development in these peculiar brachiopods. Although the spines cover the cup, a strong gap is left by the shallow trough in the lip of the posterior side. The development is thus intermediate between the conditions seen in CycJacantharia and Seslropoma. Taphrosestria? species Plate 303: figure 11 Two specimens from USNM 702-low are unlike any other richthofeniids in the collection. They are 958 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY extremely low and squat in appearance, having a very broad base and wide apical angle. The speci- mens measure 7 and 10 mm, respectively, in height and are almost circular, with a diameter of 31 mm. The margin is strongly flaring especially on the posterior side. The muscle pit is deep, and adductor and diductor scars lateral to the former are readily distinguishable. The brachial valve and protective spines, if any, are unknown. The specimens are assigned to Taphrosestria because of the shallow cups, the lack of a septum, and the deep muscle pit. Figured specimen: USNM 154083a. Genus Sestropoma Cooper and Grant, 1969 Sestropoma Cooper and Grant, 1969:8. Conical outline, cones varying from short to elongate, tapering to squat, aperture wide, hood elevated and covered by high-crowned, strongly convex net of modified protective spines. Vestibule shallow. Exterior concentrically wrinkled, strong rugose zone near aperture; apex moderately to strongly thickened by cystose shell, depending on growth habit. Rhizoid spines numerous and stout. Pedicle valve interior with stout aulacoterma and moderately strong longitudinal ridges defining pseudodeltidial region, open to interior through- out length of cone. Muscle mound carínate, elon- gate, and strongly elevated. Internal spines not strongly developed. Brachial valve generally flat to slightly convex; interior with reduced and low cardinal process; adductor scars moderately thickened; endospines reduced, in several rows, earlier ones remaining as scattered nodes. Lateral ridges moderately strong. Type-Species.—Sestropoma cribriferum Cooper and Grant (1969, pi. 2: figs. 19-21). Diagnosis.—Like Hercosestria externally, but with highly arched coscinidium and thickened muscle mound, without a median septum. Comparison.—This genus is closest to Coscina- rina, from the Permian of Sicily, and to Hercoses- tria, from the Leonardian of the Glass Mountains, each of which possesses a sievelike cover over the aperture of the pedicle valve. It is unlike Coscina- rina in the form of the cone, but more particularly in not having the myocoelidium characteristic of Old World richthofeniids. Sestropoma is more elongate than Hercosestria of the Glass Mountains in the form of the cup, and differs also in the nature of the network over the cup and the interior. The coscinidium of Sestro- poma is more even and regular than that of Hercosestria and is generally much more elevated and rounded; that of the Leonardian genus is flattened and not usually extended beyond the cup margin. Internally the two genera are also unlike, the Guadalupe Mountain genus having a mound- like muscle area with keeled summit but the Glass Mountains genus provided with a high bladelike septum. Discussion.—It is not necessary to discuss in detail all the anatomical features of this genus because some of them are exactly like those of other Richthofeniacea. The pseudodeltidial arrangement and the anchoring of the shell is exactly like that of the other genera. It may be profitable to discuss the net over the cup, the muscle region, and the little that is known about the brachial valve. Aside from the muscle region, the most distinctive feature of Sestropoma is the sievelike network, the coscinidium, overlying the aperture of the pedicle valve. This resembles that of Hercosestria but is much more regular. It is difficult to detect the originating spines, which have completely lost their identity, around the margin. Generally the coscini- dium is strongly but unevenly arched. In lateral view the sieve is gently convex nearly to its crest and then is narrowly folded to join the hood margin. This makes for a long anterior side but a short posterior side to the coscinidium. In S. cribriferum the mesh forms numerous polygonal openings about 1 mm or slightly more in their widest dimension. These do not have a definite shape and vary from elliptical to definitely pentagonal, but the inner margins are all rounded. The coscinidium is about .75 mm thick and is consequently a delicate struc- ture, especially in the silicified state. In dorsad growth of the hood, as the shell grows and expands, the hood is plastered against the outer posterior wall of the sieve. In broken specimens, the interior wall of the hood has the partially buried remnants of the sieve welded to it, making generic identification possible even when the coscinidium is destroyed. The mound forming the site of the muscle region is similar to that of Cyclacantharia and it is believed that Sestropoma was derived from Cyclacantharia NUMBER 19 959 by formation of the coscinidium. The muscle mound is greatly elongated and is formed of closely spaced large cysts. The crest of the mound is carí- nate and in some is almost septate, but a bladelike septum uniting with the inner surface of the pseudodeltidium is never formed. The sloping face of the mound has two sets of muscle scars, a larger set occupying most of the sloping face and a smaller one occupying the margin of the carina. Muscle marks at the base of the mound are not clearly visible, consequently interpretation of the scars that are visible is difficult. The ones on the long slope may be the diductors or they may be the larger adductors. It is also probable in either case that the elongate muscles on the carínate crest are scars of adductors. The brachial valve of both species of Sestropoma is very delicate; few specimens have been obtained and none of these is complete or perfectly pre- served. The cardinal process, wherever it could be seen, seems to be somewhat aborted. In one valve, it is confined almost to the myophore lobes, and in others the myophore is not conspicuous and the shafts are reduced to mere lines. The lateral ridges are indifferently developed but the adductor field seems to be somewhat more strongly thickened than is usual in other genera of this family. The individual scars, however, have not been satisfacto- rily determined nor were they seen to be dendritic. They are sufficiently thick to be separated into left and right pairs by a fairly deep groove rather than by the low ridge that is more usual among the Productidina. Endospines are clearly seen in only one specimen and these appear in two rows at the anterior. Posterior to the spine rows are scattered nodes, regarded as incompletely resorbed spines left behind in the anterior growth of the shell. Sestropoma cribriferum Cooper and Grant Plate 306: figures 36-51; Plate 307: figures 1-33; Plate 308: figures 10-21; Plate 476: figures 19-26 Prorichthofenia sp. Newell et al., 1953, pi. 21: fig. 33, pi. 27: fig- 1. Sestropoma cribriferum Cooper and Grant, 1969:8, pi. 2: figs. 19-21. Variably elongated cones with apical angle averaging 47° but varying between 29° and 76°. Cross section at aulacoterma generally elliptical, posterior side moderately to strongly flattened. Posterior side flattened but anterior side well rounded. Sides narrowly rounded. Aperture not flaring, posterior side of hood commonly higher than anterior side. Protective coscinidium forming fairly regular mesh, narrowly rounded medially or toward posterior side, strongly elevated and set deep within aperture, margin of aperture forming rim around net. Rhizoid spines stout. Pedicle valve with strong aulacoterma but with few interior spines usually located in apicad or ventral two-thirds of cone. Pseudodeltidial region open to interior or partly covered apically. Muscle mound narrow, median keel sharp and long, extending from apex dorsally to beyond middle of body chamber. Shell thickest at muscle mound. Muscle marks obscure, apparently confined to muscle mound. Brachial valve thin and delicate, nearly flat, inside with moderately thickened lateral ridges. Hinge wide but neck generally short. Adductor scars moderately thickened, separated by groove rather than median ridge. Cardinal process con- sisting of two elongated and disconnected lobes. Endospines few, anteriorly arranged. Partly resorbed endospines posterior to marginal row appearing as scattered nodes. Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Member), Bell Canyon For- mation (Hegler, Pinery, Rader and Lamar mem- bers), Capitán Formation. Localities.—Getaway: AMNH 512. Hegler: AMNH 635; USNM 731, 740c, 740d, 732a. Pinery: AMNH 397, 398, 435, 437, 524, 528, 537; USNM 725h, 725n, 733, 736. Rader: AMNH 403, 404, 410; USNM 725f, 725g, 725o, 740a, 740i, 740j. Lamar: AMNH 37, 38, 39, 40, 373; USNM; 725e, 728i, 728p, 728q, 738b. Capitán: USNM 748a. Diagnosis.—Variable Sestropoma with strongly convex, finely meshed coscinidium inset into the cup below the margin. Types.—Holotype: 151656b. Figured paratypes: USNM 151656a, c, f, h-k. Unfigured paratypes: USNM 151656d, e, g. Figured hypotypes: USNM 1516561, m; 151665; 154079a; 154080a-d, g, k, 1; 154583a-d. Measured paratypes: USNM 151656a, c- i. Measured hypotypes: USNM 151670a-e; 151676a; 151678a; 154080a, c, d; 154583a. Comparison.—This species is smaller and has a finer meshed coscinidium than 5. mexicana, new species, the only other species of the genus now known. 960 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brachial brachi/xl apical valve valve surface hinge thick- aperture aperture angle length length width length width midwidth height ness length width AMNH 410 151670a 76° 25 A 14.5 27.8 31.0 8.5 35.3 40.0 22.8 29.2 40.0 151670b 54° 25.2 17.3 24.5 45.0 7.3 29.7 39.0 21.4 2fr4 34.2 151670c 53° 18.8 14.0 22.0 33.0? 9.0 25.5 33.3? 22.0 22.0 31.4 151670d 42 o 18.8 13.3 18.5 24.0 6.3 23.0 23.8 18.5 19.7 24.3? 151670e 57° 14.8 10.0 15.0? 18.0 5.0 18.8 18.1 11.0 19.4 20.0 AMNH 403 151678a 62° 20.7 13.5 24.8 37.0 8.2 28.8 27 + 23.2 21.4 35.0 AMNH 39 151676a 52° 19.9 16.0 25.3 34.0? 7.3 2G.9 27.3 + 22.0 22.3 30.8 USNM 731 151656a 34° 19.0 16.0? 18.0? 38.0 ? 21.4 42.0 27.0? 21.4 25.4 151656b 33° 17.2 12.0? 18.0? 30.0 ? 19.0 37.0 25.0 25.9 23.9 (holotype) 151656c 26° 15.3 12.0? 14.0? 32.0 ? 15.5 32.8 ? 17.0 16.5 151656d 29° 11.5 8.0 12.0 16.0 4.5 15.9 22.0? 12.3 13.0 17.0 151656e 33° 10.2 8.0 10.0? 16.0 ? 12.4 17.7 ? 8.7 14.0 151656f 31° 8.0 7.0? 9.0? 14.0 ? 9.0 16.3 } 10.2 12.3 151656g 54° 8.0 7.0 8.5 10.0 2.0 9.6 8.1 6.0 9.3 12.0 151656h 36° 15.9 9.5 15.0 12.0 4.3 18.4 21.0 15.6 19.8 19.9 151656Í 29° 11.3 11.0? 12.5? 18 + ? 13.0 23 + ? 13.4 16.0 USNM 725f 154080a 44° 15.0 ? ? 20.0? ? 14.8 26.2 ? 15.0 17.6 154080c 63° 19.0 ? ? 32.0? ? 25.5 34.0 ? 19.3 24.4 154080d 44° 16.8 ? ? 25.0? ? 16.3 28.2 ? 18.4 18.3 USNM 740j 154583a 53° 20.0 14.0? 20.0? 42.0? 8.6 25.5 38.0 + 23.0? 22.8 25.5 Discussion.—Specimens of this genus are not common in the Bell Canyon Formation, conse- quently the collection is not large enough to permit analysis of the variation seen in the specimens we have. We have not seen such large clusters of shells as those of other richthofeniaceans that occur in the Glass Mountains, so we are unable to evaluate the variation clue to crowding. The species seems to have lived in small clusters of a few specimens rather than in patch reefs. The variation occurs in the form of the cup and in the coscinidium. Long slender forms of the species, such as the type speci- men, occur in the lower part of the Bell Canyon Formation in the Hegler Member. Some short forms are also found. In the upper part of the Bell Can- yon the specimens tend to be larger and wider, but here, too, slender forms are found. It seems best to recognize only the one species until more can be discovered about the limits of variation. Growth series are not present in detail but some young individuals are preserved. Unfortunately, it is not possible to state exactly at what size the coscinidium was formed. Specimens less than 7 mm in height appear not to have a sieve but do have a ring of incipient spines. Specimens with a height of 10 mm appear to have a sieve. One specimen 8 mm high has no trace of the coscinidium, nor are the incipient spines in evidence. Another specimen (USNM 152694) about 20 mm high has an incom- plete coscinidium which suggests how it originated. The spines on the anterior side have lateral branches, but most of these have not yet joined their fellows. On the posterior side the spines are flattened and completely interconnected. The me- NUMBER 19 961 dian region is open; presumably continued growth would have closed it. Sestropoma mexicanum, new species Plate 284: ficures 31-33 Large, conical, apical angle of 75°; dorsal side conspicuously flattened, sides narrowly rounded; apex bent slightly in dorsad direction. Marginal lip long; coscinidium strongly convex with apex about midway, strongly elevated above marginal lip of aperture and with coarse pores. Dorsal valve un- known. Measurements (in mm).—From locality USNM 815, specimen 153675 (holotype): length 22.5, width 29.0, thickness 19.0?, height 41.7, aperture length 31.8, aperture width 40.5. Stratigraphic Occurrence.—Guadalupian (Wa- agenoceras Zone). Locality.—USNM 815 (= AMNH 1028). Diagnosis.—Large wide Sestropoma with nar- rowly domed coscinidium having the crest at about mid-aperture. Types.—Holotype: USNM 153675. Comparison.—This is a wider, stouter, and larger species than that of the Bell Canyon Formation, and the coscinidium has its crest at midvalve rather than near the dorsal side, as in S. cribriferum. Genus Collumatus Cooper and Grant, 1969 Collumatus Cooper and Grant, 1969:6. Small, squat cups attached directly to substrate but often with expanded base of attachment; no attachment spines; aperture elliptical to round de- pending on attachment, covered by lacy network (coscinidium) as in Hercosestria but with open channel on posterior side. Sides smooth, without any ornament. Pedicle valve interior with narrow ridge (aulaco- terma) around inside on which brachial valve rests. Hinge narrow; sockets small, defined by narrow shelf on each side of hinge area; posterior edge of brachial valve inserted in narrow groove in poste- rior wall of pedicle valve; muscle scars on valve floor; diductors somewhat flabellate; anterior side marked by low, wide ridge. Brachial valve interior with narrow hinge; car- dinal process bilobed and with large bilobed myo- phore; myophore posteriorly partially covered by narrow convex chilidium. "Tooth" small. No myo- phragm. Adductors scars thickened; no endospines. Type-Species.—Collumatus solitarius Cooper and Grant (1969:6, pi. 1: figs. 22-26). Comparison.—This genus need be compared only with those having a network over the aperture, i. e., Hercosestria, Coscinarina, and Sestropoma. Collumatus differs from all these in being cemented directly, and by a large surface, to the substrate, completely devoid of spines. It has no septum like that of Hercosestria and does not develop a thick- ened muscle area like that of Sestropoma. Coscina- rina from Sicily has a myocoelidium, a structure not yet seen in adult richthofeniids in North America. The growth form is unlike that of the other genera except Hercosestria which has a similar, squat form. Discussion.—The unique features of this genus are its growth form and its method of cementation, leading to a solitary habit; its complete lack of anchor spines; and the absence of endospines on the inside of the brachial valve. The known richthofeniaceans are colonial in habit, usually forming small clusters, masses or perhaps patch reefs. The individuals are initially cemented at the apex, usually a small point, and braced by struts in the form of rhizoid or cementing spines. In con- trast, Collumatus cements by a broad surface to shells and other parts of the substrate. Only indi- viduals have been found, and the form of the cica- trix indicates that it had no connection with any other individual by cementation. One specimen occupies the interior surface of a small Neospirifer brachial valve. Others have elliptical cicatrices, in- dicating attachment to a thick bryozoan branch or other round object, such as a crinoid stem. One is attached to the convex surface of a small Enteletes, another to Meekella. Every specimen appears to have had a solitary existence. No spines were seen on any of the specimens. Cementation and strengthening of the cup seems to have taken place by deposition of successive smooth sheets, one draped over another. These act instead of spines and may be a specialized attachment ar- rangement corresponding to the spines of other richthofeniaceans. 962 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY The hingement of the valves is like that of other genera of the Richthofeniacea. In Collumatus there is a more strongly developed notch in the posterior wall for the movement of the brachial valve. No specimen shows any trace of a myophragm in the pedicle valve and the brachial valve appears to have lost completely the endopsines so characteristic of Hercosia and Cyclacantharia. Collumatus solitarius Cooper and Grant Plate 89: ficures 24-30; Plate 92: ficures 1-25; Plate 305: figures 21-53; Plate 306: figures 1-35; Plate 309: ficures 16-29 Collumatus solitarius Cooper and Grant, 1969:6, pi. 1: figs. 22-26. Small, solid, crater-like shells with expanding base and broad, irregular attachment surface. Aper- ture narrower than base and covered by coscini- dium with elliptical opening along posterior margin of pedicle valve. Sides smooth, formed by draped sheets of shell substance; aperture margin thickened and rounded. Surface without ornament and without attachment spines. Pedicle valve as above but with moderately thick- ened aulacoterma, strongest on anterior side. Bra- chial valve gently convex, narrowly elliptical in outline, with narrowly rounded sides, and with an- terior margin slightly indented medially. Surface smooth. Interior as defined for genus. Measurements (in mm).— brachial brachial hinge aperture aperture length valve length width valve width width length width USNM 732j 153043a 13.3 7.3 15.0 10.0 4.0 5.0 10.5 153043b 23.5 9.6 23.7 16.2 5.2 10.6 16.4 153043c 17.3 8.8 21.6 13.6 ? 8.2 14.1 153043d 17.8 8.5 25.0 11.9 4.2 7.6 12.0 153548a 11.0 c. 7.5 12.4 c. 10.4 ? 10.0 9.0 (holotype) Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USNM 700v, 732j, 736x, 737y. Diagnosis.—Richthofeniacea having a solitary habit and anchored by broad cementation rather than by spines. Types.—Holotype: USNM 153548a. Figured paratypes: USNM 153548b-d, f, g. Figured hypo- types: USNM 153043a-d, f, g, o, p; 154088a-j; 154089a-d; 154090; 154114a, b; 154526a-c. Mea- sured hypotypes: USNM 153043a-d. Unfigured para- type: USNM 153548e. Comparison.—No other species of the genus is known. Discussion.—Nearly all specimens of this species in the collection had been ripped off their moorings and were found in a shell breccia. Inasmuch as the attachment scars are large, the specimens may have been torn loose during a violent storm. It is not known just what niche C. solitarius may have oc- cupied but it must have been in sheltered spots on the bottom among broken shells and other debris. Family RICHTHOFENIIDAE Waagen, 1885 Richthofeniacea having a myocoelidium in the pedicle valve. Genus Richthofenia Kayser, 1881 Richthofenia Kayser, 1881:352; 1883:74, 195. Richthofenia species Plate 200: figures 35-41 Specimens of this genus are figured for compari- son with members of the Hercosiinae and Cyclacan- thariinae. Neither of these has a myocoelidium for lodgement of the muscles. The specimens illus- trated from the Salt Range, Pakistan, have an un- usually large development of cystose shell in the pedicle valve. Figured specimens: USNM 154051a-c, f. NUMBER 19 963 Subfamily PRORICHTHOFENIINAE Muir-Wood and Cooper, 1960 Full characteristics of the subfamily uncertain. As explained in detail in the discussion of Cycla- cantharia, the genus Prorichthofenia, which is based on Crania permiana Shumard, is at present an uncertain concept. Shumard's specimens, now lost, came from the "White Limestone" of the Guadalupe Mountains. Girty (1909) attempted to interpret Shumard's species but based his views on specimens from rocks much older in the Glass Mountains than the "White Limestone" (= Capi- tan-Carlsbad Formations). As a basis for his genus Prorichthofenia, R. E. King (1931) chose his own interpretation of Girty's conception of Crania permiana. The White Limestone contains two genera of richthofeniids, but which one Shumard had, or whether he had both of them or neither, will probably never be known. We have felt it best therefore to leave Prorichthofenia in a nebulous state. Superfamily PRODUCTACEA Gray, 1840 Family OVERTONIIDAE Muir-Wood and Cooper, 1960 Productacea with brachial ridges oblique; sessile bilobed cardinal process, each lobe posteriorly in- cised, rarely with minute median lobe; cardinal process supported by septum; exterior spinose, rugose, or lamellose, rarely anteriorly costa te. Subfamily OVERTONIINAE Muir-Wood and Cooper, 1960 Overtoniidae with exterior spinose, rugose, or lamellose, rarely anteriorly costate. Genera in West Texas: Fimbrinia Cooper, 1972; Simplicarina, new genus; Rhytisia, new genus. The members of this subfamily are rare and ob- scure shells, mostly small and fairly restricted. Fimbrinia is found in the Sierra Diablo and the Glass Mountains but the other two are only known from the Glass Mountains. Genus Fimbrinia Cooper, 1972 Fimbriaria Muir-Wood and Cooper (not Froelich, 1802), 1960:186. Fimbrinia Cooper, 1972:450. Small, suboval, hinge generally narrower than midwidth. Cardinal extremities obtuse, without spines; valves deeply concavoconvex. Valves orna- mented by broad concentric bands, each bearing row of stout spines. Brachical valve with more slender spines and rows of dimples. Pedicle valve interior without adductor ridge but with ear deflected ventrally, with low baffle. Brachial valve interior with divided posterior platform, widely bilobed cardinal process in ven- tral and dorsal views. Adductor scars on anteriorly elevated platform with posteriorly attenuated ends also elevated. Breviseptum short, not reaching mid- valve and terminating at anterior end of adductors. Brachial ridges directed anterolaterally. Endospines numerous, long and stout. Type-Species.—Overtonia plummeri R. H. King (1938, p. 276, pi. 39: figs. 19-22). Discussion.—This is a rare genus in Pennsylva- nian and Permian rocks of the United States; con- sequently, any interior features revealed are of interest. Specimens from the Sierra Diablo exhibit details of the brachial valve interior. Interior characteristics of the pedicle valve are still uncertain, because all the specimens recovered from the Sierra Diablo are thin and delicate. These fail to reveal the muscle scars but show clearly that the adductors were not attached to a ridge, as in many genera. The beak is strongly incurved and hangs over the hinge. Ears are not well-developed but are deflected toward the ventral valve. Some specimens have on their inside a low and narrow baffle that runs just inside the hinge to the ear, then just under the outer margin of the ear to disappear on the lateral slope. Chief interest in the interior details centers about the cardinal process and the adductor platform. The cardinal process is attached to a fairly well developed posterior platform. It is bilobed in ven- tral and dorsal views and a median lobe is not de- veloped in the largest specimens in the collection from the Sierra Diablo. The cardinal process thus maintains a productellid appearance in the species thus far studied. The adductor scars are located on thick teardrop- 964 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY shaped callosities that are strongly excavated ante- riorly. At the posterior end of these callosities a narrowly-looped ridge surrounds the attenuate end, the two forming a short but deep trough lying on the posterior platform that forms the floor of the depression. The outside of the loops unite with the brachial ridges. The breviseptum is very short and scarcely extends anterior to the muscle platform. At its anterior end, it is bladelike and strongly ele- vated but terminates abruptly and does not reach midvalve. The anterior slope, which occupies about two-thirds the valve length, is marked by scattered, thick, sharply pointed endospines. The exterior of Fimbrinia is distinctive among Permian productids because of its regularity and some unusual details. Both valves are characterized by a single row of spines occupying the middle of each lamella. The lamellae are elevated into crests at the spines and then continue anteriorly nearly flat or slightly concave almost to the next anterior row of spines. Since each newly formed lamella originates on the inside just anterior to the row of spines, the anterior half of the posterior lamella overlaps the posterior half of the next anterior lamella. In most specimens these thin and delicate lamellae are commonly broken off or are raggedly preserved. When complete, they terminate near the place of origin of the spine row, and, in some in- stances, their distal margin lies on the spines. A similar condition exists in the brachial valve, where the anterior, free part of the lamella often lies over the base of the spines of the next row forward. Deep dimples, probably corresponding to the spines of the pedicle valve; appear in rows on the posterior part of the lamellae of the brachial valve. Stratigraphic and Geographic Distribution.— Because of its great rarity, little is known about the distribution of this genus in time and space. It appears in the Wolfcampian of Bolivia where Kozlowski (1914) described Productus cristato- tuberculatus. King (1931:82) listed Kozlowski's species in the Udden iles-bearing Shale Member fauna. The type-species of Fimbrinia occurs in the same zone in north central Texas (lower Cisco) and in several other formations higher in the Pennsyl- vanian. Stehli (1954:326) identified the type species in the lower part of the Bone Spring Formation in the Sierra Diablo. In the Glass Mountains we have found the genus in the Uddenites-bearing Shale Member and in the overlying Neal Ranch and Lenox Hills formations where it is very rare. The youngest occurrence of the genus in the Glass Mountains is in the basal Skinner Ranch Formation (equivalent of the Decie Ranch Member) which corresponds to Stehli's dis- covery in the Bone Spring of the Sierra Diablo. This seems to be the final appearance of the genus. Fimbrinia ovaia, new species Plate 310: figures 1-31 Overtonia plummeri Stehli (not R. H. King), 1954:327, pi. 23: figs. 5-7. Moderately large for genus, elongate oval to subtriangular in outline; hinge narrower than mid- width; sides and anterior well rounded. Cardinal extremities obtuse. Surface marked by concentric bands bearing single row of moderately long, anteriorly curved spines, about 12 rows anterior to umbonal region in large adults. Brachial valve similarly marked but concentric bands bearing large dimples as well as spines more slender than those of pedicle valve. Pedicle valve with strongly convex lateral profile, umbonal region narrowly rounded but middle and anterior regions less so. Anterior profile narrowly convex, sides steeply sloping. Beak strongly in- curved, umbonal region protruding considerably posterior to hinge. Median region narrowly swollen, swelling continuing anteriorly to form slight ven- tral fold in anterior margin. Umbonal slopes pre- cipitate; lateral slopes steeply sloping. Brachial valve slightly wider than long, deeply concave in median region. Sides and anterior sloping medially fairly evenly; anterior margin slightly and narrowly sulcate to accomodate ventral fold of pedicle valve anterior. Pedicle valve interior with moderately developed baffle across ears. Brachial valve interior with small bilobed cardinal process on prominent and somewhat elevated posterior platform. Adductor scars on anteriorly elevated and excavated callosities with narrowly looped ridges anterior to cardinal process. Breviseptum anteriorly strongly elevated but short. Anterior slopes strongly endospinose but endospines stout and scattered. Brachial ridges poorly developed. NUMBER 19 965 Measurements (in mm).—Thickness unmeasur- able. brach- ial sur- valve face hinge mid- length length length width width height USNM 728f 152701a 13.4 10.0 19.0? 7.7 11.7 7.8 (holotype) 152701b 10.8 8.1 18.0 6.9 10.5 5.8 152701c 10.2 7.9 17.0 7.3 9.7 5.5? 152701d 9.4 7.8 15.5 5.7 8.6 5.0 152701e 7.7 6.7 13.0 4.8* 7.8* 4.3 152701f 7.0 6.3 9.0? 6.4 7.1 3.2 152701g 4.6 4.2 ? 3.9 4.6 1.9 152701h 9.7 7.9 ? 8.3 10.7 6.1 152701Í ? 7.8 ? 7.2 9.5 ? 152701J ? 9.0 ? 9.1 11.7 ? Stratigraphic Occurrence.—Bone Spring For- mation (lower), Skinner Ranch Formation (lower). Localities.—Bone Spring: AMNH 628, 696; USNM 725c, 728e, 728f, 728h. Skinner Ranch: USNM 705a, 720e, 724q. Diagnosis.—Coarsely lamellose Fimbrinia with narrow hinge in the adult. Types.—Holotype: USNM 152701a. Figured paratypes: USNM 152701i-m; 153873; 153874a-c. Measured paratypes: USNM 152701b-j. Unfigured paratypes: USNM 152701b-h. Comparisons.—The ornament and size of this species are like those of F. plummeri (R. H. King) of the late Pennsylvanian or early Permian, but the main difference is the much narrower hinge of the Sierra Diablo species. Fairly young specimens are like F plummeri in having the hinge slightly narrower than the midwidth, but in the adult the hinge is much narrower, creating an almost subcarinate condition. Some differences between the two species appear inside the brachial valve. The cardinal process of F. ovata is more delicate, but the adductor platform is more elevated and is excavated anteriorly. The platform of F plummeri is thick but not clearly defined. A thickened marginal rim in F. plummeri is absent in the Sierra Diablo species, and the lateral ridges of the Graham Shale species are better defined than those of F. ovala. Fimbrinia plummeri (R. H. King) Plate 311: figures 5-14 Overtonia cristato-tuberculata R. E. King (not Kozlowski), 1931:82, pi. 20: figs. 1-3. Overtonia plummeri R. H. King, 1938:276, pi. 39: figs. 19-22. —Muir-Wood and Cooper, 1960:186, pi. 46: figs. 1-9. This species was described fully by its author, and its anatomy was later elaborated by Muir-Wood and Cooper, so it seems unnecessary to make further description. Specimens answering fully to the characters of this species were collected and described by R. E. King from the Glass Mountains. A few specimens of Fimbrinia in the silicious residues from beds 9-12 of the Neal Ranch For- mation appear to be juveniles. These are wide- hinged and subcircular in outline. The largest specimen measuring 8 mm in length has 20 spines around the margin, the number appearing at the same length in specimens of F plummeri from the Graham Formation. The Wolfcampian specimens are therefore placed tentatively in this species. Types.—Figured specimens: YPM 11499a, b. Stratigraphic Distribution.—Gaptank Forma- tion (Uddenites-bearing Shale Member), Neal Ranch Formation (beds 4-14 of P. B. King). Localities.—Uddenites: King 88, 94, 94s and Tba. Neal Ranch: USNM 701, 701a3, 701d. Fimbrinia species unidentifiable Plate 310: figures 32-34; Plate 311: figures 1-4 Three lots containing this genus are represented by poorly preserved specimens that cannot be satisfactorily placed in any of the known species. Species 1.—Six decorticated specimens preserved in conglomerate indicate a species suggesting F ovata, new species. The pedicle valves are elongate- oval and narrow-hinged. The brachial valves appear shallow and are much pitted. The specimens come from the Lenox Hills Formation at USNM 707j and possibly USNM 715. Figured specimens (PI. 311: figs. 1-4): USNM 153999a, b. Species 2.—A small, poorly preserved silicified specimen from USNM 727e has a fairly wide hinge and preserves some of its spines. Figured specimen (PI. 310: fig. 32): USNM 153876. Species 3.—An immature specimen possibly re- lated to F. ovata was found at USNM 728—1. Figured specimen (PI. 310: figs. 33, 34): USNM 153877. 966 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Simplicarina, new genus [Latin simplicis (unmixed)] Small, deeply concavo-convex, subrectangular, hinge as wide or wider than midwidth; ears small; beak small, not strongly umbonate; anterior margin with modest dorsad fold. Surface smooth; spines few, two on lateral slopes, one or two on trail. No brachial valve spines. Pedicle valve interior with moderately developed ear baffle; adductor scars large, slightly thickened; diductor scars marked by small, thick endospines. Brachial valve interior with small elongate, sessile bilobed cardinal process on posterior platform at high angle to posterior margin; ear baffles low, serrated, extended laterally as low submarginal rim forming thickening on anterior side of visceral region. Adductor scars elongate, teardrop-shaped, small; breviseptum low. Brachial ridges somewhat oblique, not strongly thickened. Type-Species.—Simplicarina incompta, new spe- cies. Diagnosis.—Generalized Overtoniinae with few spines. Comparison.—This small genus suggests Echin- auris but is not provided with the characteristic brush of spines on the ears that is so distinctive of that genus. It also lacks any spines on the brachial valve. Simplicarina suggests the Early Mississippian Geniculifera Muir-Wood and Cooper in its paucity of spines, but that genus, which also possesses few spines, has them placed differently, mostly on the trail and posterior margin rather than on the lateral slopes as in Simplicarina. Simplicarina incompta, new species Plate 310: figures 35-41; Plate 312: ficures 25-50 Small; subrectangular outline, hinge straight, about equal to midwidth; sides slightly oblique and gently rounded; anterior margin broadly rounded with slight median flattening. Body cavity thin. Flanks and umbonal slopes marked by two stout spines; trail with few scattered spines creating obscure costae. Pedicle valve strongly convex in lateral profile, strongly domed in anterior profile, steep slopes; median region with well-defined sulcus originating in umbonal region; anterior slope gently convex, long, and steep. Umbonal and median regions strongly swollen. Beak small; umbo protruding slightly posterior to posterior margin. Ears small, not protruding, moderately rounded approximately at right angle. Brachial valve deeply concave, sides and anterior sloping steeply to deepest part at midvalve; ears small, slightly concave. Pedicle valve interior with small ear baffles and slightly thickened, fairly large adductor field. Brachial valve interior with small, narrow cardinal process, low breviseptum, elongate adduc- tor field, and faintly thickened brachial ridges. Ear baffles serrated, continuing as submarginal rim around entire visceral region. Measurements (in mm).— USNM 721j 151585a 151584 USNM 720d 151583 USNM 726d 153927a (holotype) brachial surface mid- hinge thick length valve length length width luidth height ness 8.0 6.9 15.0 8.3 8.6 4.3 1.3 10.0 8.3 17.0 10.5 8.7 5.8 3.2 7.8 6.8 12.0 8.5 8.0 4.4 1.4 11.5 9.5 20.0 12.0 12.5 7.5 3.0 Stratigraphic Occurrence.—Road Canyon For- maton (upper). Localities.—USNM 720d, 721j, 721z, 722e, 726d. Diagnosis.—Simplicarina with a wide shallow sulcus on the pedicle valve. Types.—Holotype: USNM 153927a. Figured paratypes: USNM 151583, 151585a-c. Measured par- atypes: USNM 151583, 151584, 151585a. NUMBER 19 967 Comparison.—This little shell suggests some spe- cies of Echinauris but it is less spinose than the members of that genus and has no spines on the brachial valve. Discussion.—This is a rare species found only in the Road Canyon Formation. On the exterior the development of the sulcus or anteromedian flatten- ing of the pedicle valve appears to be associated with the presence of two spines on the trail. These are moderately spaced and produce a longitudinal costa which helps to define the sulcus. On the inside of the pedicle valve the spines of the exterior penetrate the shell and are defined by fairly long tubes. Rhytisia, new genus [Greek rhytis (fold)] Small, subquadrate to subcircular in outline; hinge usually narrower than midwidth; ears small and inconspicuous; beak small; anterior margin undeflected. Surface with umbonal and visceral regions of both valves marked by strong, concentric wrinkles. Halteroid spines strong, few, scattered at random; ears smooth or each occupied by single spine. Brachial valve without spines. Pedicle valve with delthyrial opening nearly ob- solete; ear baffles fairly strong; musculature well preserved with flabellate diductor scars not anteri- orly surrounding elongated, teardrop-shaped ad- ductors. Brachial valve with small cardinal process, bi- lobed in ventral and posterior views; shaft short, buttressed by low median ridge divided into two at base of shaft but narrowing and becoming one where joining short anteriorly elevated breviseptum. Endospines small and delicate; brachial ridges obliquely elongated; ear baffles low, oblique ridges; adductor scars, elongated, teardrop-shaped, slightly elevated, median set larger than lateral scars. Type-Species.—Rhytisia rugosa, new species. Diagnosis.—Concentrically wrinkled Overtoni- inae with scattered halteroid spines on the pedicle valve but no spines on the brachial valve. Comparison.—This genus has an appearance very similar to that of Echinauris and Simplicarina. Its strong wrinkles and lack of long, bunched-to- gether halteroid spines on the pedicle valve and the lack of spines on the brachial valve separate it from Echinauris and other genera having brachial valve spines. The more numerous spines and concentric wrinkles are a ready means of spearation from Simplicarina, which has few spines and a shell with obscure radial ornament. Discussion.—This is an uncommon shell, so far known only from a few localities in the Road Can- yon Formation. It is difficult to identify when occuring with abundant Echinauris, whose young it simulates. It is, however, not a young form of another genus because the valves are thick and stout, clearly indicating adult specimens. The rugosity of the exterior is not uniformly well preserved because some specimens retain it only on the slopes, whereas others have it only on the umbonal region. Well-preserved specimens have the valve wrinkled for more than half the length. Most pedicle valves preserve the wrinkles well, even in specimens in which they are worn or poorly developed on the brachial valve. We have been unable to determine a fixed pattern for the spines on the pedicle valve. A few specimens have a spine on one ear or the other or on both ears, but they are not common. Well preserved spines are long, often equal to the shell length. The spines are stout and are given off at a fairly high angle, 30° or more. They usually come directly from the shell and are not attached to spine ridges as in Avonia, Krolovia, and Levipustula. Inside the pedicle valve the delthyrial opening is nearly obsolete and is very small; the ear regions are considerably thickened and flattened and the ear baffles are slightly fluted. The diductor scars are subflabellate and triangular but do not sur- round the adductor scars anteriorly. The adductor scars are elongated, slightly thickened, and tear- drop-shaped and have the same appearance and size as the median adductor scars of the brachial valve. The spine openings inside the pedicle valve are narrowly elliptical and have thickened rims. The brachial valves are moderately to strongly concave and are variably thickened internally. The cardinal process is small and narrowly bilobed with each lobe having a median incision. The lobes coalesce proximally and form a pointed extension that protrudes slightly beyond the umbo and served as a lophidium. The lateral ridges are short and extend into the low, slightly fluted ear baffles that extend anterolaterally almost to midvalve. The breviseptum is anteriorly elevated and descends posteriorly to join the median ridge that bolsters 968 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY the cardinal process. This ridge divides posteriorly to form a double ridge like that of Leioproductus. The median adductor scars are elongate, teardrop- shaped, and commonly slightly thickened. The lat- eral scars are simlarly shaped but smaller. Some specimens have a short ridge extending part way anteriorly between the lateral and median scars. The brachial ridges are well marked in many speci- mens and are greatly elongated anteriorly, as in the Overtoniinae. Rhytisia rugosa, new species Plate 311: figures 15-59 Subquadrate to subcircular outline, hinge usually narrower than greatest width at midvalve; sides gently to moderately rounded; anterior margin strongly rounded, Ears small, slightly protuberant, rounded to subangular; anterior commissure with- out deflection. Surface with posterior half or two- thirds marked by strong, narrowly rounded, fairly regular, concentric wrinkles. Spines all halteroid, stout, fairly long, length often equal to valve length arising at fairly high angle of 30° to 60°, curved anteriorly, and distributed in no discernible pattern. Brachial valve ornamented by wrinkles only, usually confined to posterior half. Pedicle valve strongly and evenly convex in lat- eral profile and narrowly and strongly arched in anterior profile; sides very steep. Umbonal region strongly swollen; beak slightly protruding over umbo of opposite valve. Median region inflated; anterior slope steep. Brachial valve moderately to fairly deeply con- cave, greatest concavity at midvalve, with steep slopes all around; ears flattened. Pedicle and brachial valve interiors as defined in generic description. Measurements (in mm).— brachial surface mid- hinge thick- length valve length length width width height ness USNM721Z 152703a 8.3 ? 15.0 10.0 8.6 4.9 ? 152703b 7.7 ? 12.0 8.5 8.3 3.7 ? 152703c 8.5 7.5 13.5 9.7 6.8 4.3 2.5 (holotype) 152703d 7.7 ? 12.5 7.8 5.2 4.1 ? USNM 724c 152704a 9.4 ? 14.5 10.5 10.0 4.9 ? 152704b 8.9 ? 14.0 9.9 8.0 4.4 ? 152704c 8.4 ? 13.0 8.2 6.5 4.4 ? 152704d 7.8 ? 12.0 8.8 5.8 3.8 ? 152704e 6.9 6.0 10.5 7.3 6.4 3.2 1.7 152704Í 5.9 5.5 9.0 6.3 4.6 2.8 1.4 152704g 5.7 5.0 8.5 6.7 6.0 3.7 2.1 USNM721J 152979a 11.0 8.7? 18.5 11.0 8.3 6.0 ? 152979b 8.9 7.5? 16.0 8.0 8.7 5.0 ? 152979c 8.3 7.1 13.0 8.6 8.5 4.7 ? 152979d 8.5 7.0 12.0 8.3 7.9 4.2 ? 152979e 8.2 7.3 13.0 7.7 7.0 4.2 ? Stratigraphic Occurrence.—Cathedral Moun- tain Formation, Road Canyon Formation. Localities.—Cathedral Mountain: USNM 72lu. Road Canyon: USNM 706f, 720d, 721j, 721x, 721y, 721z, 722e, 723x, 724c, 726d, 726e, 732j, 736x. Diagnosis.—Small Rhytisia with strongly wrin- kled posterior and stout halteroid spines. Types.—Holotype: USNM 152703c. Figured paratypes: USNM 152703b, e-i, k, 1; 152704 b, d, i-k; 152979a, c; 154000a, b. Measured paratypes: USNM 152703a, b, d; 152704a-g; 152979a-e. Un- figured paratypes: USNM 152703a, d, j; 152704a, c, e-h; 152979b. Comparison.—No other species of this genus is known. Discussion.—Several specimens of this species NUMBER 19 969 have been found with attachment rings on the beak. This suggests that they were attached in youth but lived loose on the sea bottom in later life. The species is variable in respect to convexity, promi- nence of the umbo, and wrinkling. The shell has a tendency to smooth out the wrinkles in the anterior of the shell. Family MARGINIFERIDAE Stehli, 1954 Progressive, small or medium Productacea, usu- ally with a few scattered or symmetrically arranged spines; pedicle valve with or without marginal ridges. Brachial valve interior usually with mar- ginal ridge or anterior rows of endopsines; trilobed cardinal process with median lobe bent in a dorsal direction. Subfamily MARGINIFERINAE Stehli, 1954 Marginiferidae having continuous externally ge- niculated marginal or submarginal ridges around the visceral disc of the brachial valve; adductor scars smooth. Genera in West Texas: Hystriculina Muir-Wood and Cooper, 1960; and Kozlowskia Fredericks, 1933. Members of this family in the Glass Mountains are confined to the Lower Permian, where they are uncommon. These genera are more abundant and characteristic of the Pennsylvanian. Both genera are rare to common in parts of the Wolfcampian, but Kozlowskia is believed to extend into the Leonardian. Genus Kozlowskia Fredericks, 1933 Kozlowskia Fredericks, 1933:29.—Muir-Wood and Cooper, 1960:212.—Williams et al., 1965:H479. Small, alate margmiferids with strongly convex pedicle valve^ moderately concave and geniculated brachial valve. Hinge usually forming widest part. Pedicle valve with sulcus varying in development in different species, usually not strongly developed. Surface costellate to obscurely costate, ribbing tend- ing to obsolescence in some species; visceral disc and ears wrinkled in some species. Spines confined to pedicle valve, variable; in row along posterior margin; curved row at base of lateral slope, with anteriormost spine large and stout; two or more stout spines on trail; scattered small spines on body of shell. Brachial valve without spines but with anterior and lateral border of overlapping trails. Pedicle valve interior with elongated and usually thickened adductor platform; ear baffles strong and deeply corrugated on inside surface, extended an- teriorly and medially in some species as low sub- marginal ridge. Brachial valve interior with small sessile, trilobed cardinal process, usually with only slight develop- ment of posterior platform. Lateral ridges variable, but ear baffles strongly developed and continued anteriorly and medially as strong, flattened mar- ginal ridge at edge of visceral disc. Adductor scars usually thickened, forming platform; breviseptum distally elevated and reaching midvalve; brachial ridges usually well developed, commonly greatly thickened. Endospines few, usually in one or two rows, generally stout, commonly long and rarely greatly elongated. Type-Species.—Productus capacii d'Orbigny (1842:50, pi. 3: figs. 24-26). Diagnosis.—Marginiferidae with large ears, sub- dued ornament and a band of trails on the brachial valve. Comparisons.—The prominent band of over- lapping trails distinguishes this genus from all other members of the Marginiferidae in the Glass Moun- tains. Hystriculina might be confused with Kozlow- skia because of its similar ornament and general configuration, but the lack of trail bands and greatly extended ears make separation easy. Kozlowskia is most like Marginifera of the de- scribed Marginiferidae occurring outside of the Glass Mountains, as it possesses the prominent mar- ginal band and general configuration. The two genera differ in the arrangement of the spines and in the development of the trails. Marginifera has numerous spines on the lateral slopes (Grant, 1968) whereas Kozlowskia has few and the Pakistan uenus is not provided with a band of trails on the exterior. Discussion.—The various species of this genus have a distinctive form as well as a characteristic interior. Most of them are widely alate but when found are usually so broken at the hinge that their true width is seldom seen. Specimens dissolved from limestone best exhibit this important character, al- though some specimens preserving the points are occasionally found in matrix. Usually the specimens 970 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY are found weathered from shale and the ear points are seldom preserved in this type of occurrence. Besides the ear points the bulbous nature of the pedicle valve and the peculiar geniculation poste- rior to the middle are equally distinctive. In some species the body of the shell is so bulbous that the length and width are almost equal. The sulcus is an evanescent feature commonly well formed in the Pennsylvanian species but less so in the Permian ones. Kozlowskia splendens (Norwood and Prat- ten) usually has on the pedicle valve a strong but narrow sulcus extending from the venter to the front margin, but the sulcus of K. alata and K. subsphaeroidalis, both new species, is very indiffer- ently developed. Inasmuch as the presence of a fold is dependent on the formation of a sulcus, this feature of the brachial valve is evanescent. The spine arrangement is generally fairly simple but is not the same in all species. Generally six strong spines, or modification of this arrangement occur on each species: a large spine on each ear, a large spine at the base of the lateral slopes, and two large spines on the trail. When favorably preserved, these spines are roughly arranged in a horizontal row around the body of the valve when it lies on its margins. All six spines are seldom preserved. In some species, at least in adulthood, no ear spine is developed. The large spine at the base of the lateral slopes is the end member of a row of four spines that curve from each side of the beak at the base of the lateral slope nearly to the front margin. The two trail spines may be two or several, but numer- ous trail spines are not usually present. Generally the umbonal region has few spines and the rest of the shell body has a few scattered spines. The most diagnostic character of the genus is the concentration of trails in a narrow zone around the visceral area of the brachial valve. As the valves grow and the margin on the interior thickens and expands, a new trail is formed to close the anterior gap between the two valves. The older the speci- mens, usually the more trails; one specimen of K. splendens (Norwood and Pratten) (USNM 124027b) has 7 trails on the margin. Usually the brachial valve trail anterior to the margin is thin, delicate, and seldom preserved. Consequently, it is rare to find a specimen of Kozlowskia preserving any of its anterior trails. Specimens from USNM 705a are almost unique in preserving the last trail of the brachial valve almost entire. These speci- mens too have an exceptional development of the marginal ridge. The interior of the pedicle valve of most species is characterized by an elongated and elevated ad- ductor platform. This is usually elongate and tri- angular in outline, with the anterior somewhat expanded. Two teardrop-shaped dendritic muscle scars can usually be distinguished. The diductor scars are fiabellate and in K. splendens are located in front of the adductor platform. In this species the old portion of the didcutor scar is covered by callus. The ear baffles of the pedicle valve are usually well formed and close off a fairly spacious ear. The inner surface of the baffle and the inner side of the valve for some distance are generally strongly cor- rugated. In many specimens the ear baffles die out anteriorly, but in others they extend nearly to the front margin where they turn inward and unite medially, thus forming a low ridge around the visceral region. The interior of the brachial valve is variable among species but most of them have some details preserved. The cardinal process is generally small but variable. It is the characteristic marginiferid type with a median depression and the median lobe inclined strongly posteriorly. The most exaggerated form of the cardinal process appears in K. hay- denensis (Girty) in which the narrow median lobe is greatly curved posteriorly but anterior to it a great thickening of the base of the cardinal process is extended anterolaterally. Lateral ridges are variably developed within species and within specimens of the same species. Commonly the groove behind the lateral ridge is deeply pitted to receive granules in a similar posi- tion on the pedicle valve. Ear baffles are strongly developed in all the species, and these are deeply corrugated on their outer face and interlock with the corrugations of the pedicle valve ear baffles. The marginal ridge extends anteriorly and medi- ally from the ear baffle. In most specimens this is not extravagantly developed, but in K. alata, new species, it forms a shelf hanging over the inner surface of the trail. In one specimen of K. hay- denensis the marginal ridge has grown inward so far that it has engulfed the distal ends of the long endospines. The adductor platform and breviseptum present no features different from other members of the NUMBER 19 971 family. Generally they are moderately to strongly developed, but in some species bizarre thickenings are produced, as may be seen in K. haydenensis and K. alata. The same is true of the brachial ridges, which are enormously thickened in the former species. Stratigraphic Occurrence.—In the Glass Mountains Kozlowskia occurs in the Gaptank For- mation, notably in bed 10 of P. B. King (1931). It is found in the Neal Ranch Formation but is rare; it is also rare in the Lenox Hills Formation. It is fairly common in the lower Scacchinella bed (Decie Ranch Member) of the Skinner Ranch Formation, which is its final appearance in the Glass Moun- tains. Kozlowskia alata, new species Plate 312: figures 1-20; Plate 453: figure 34 About medium size for genus, length and width variable, body usually subquadrate in outline; hinge forming widest part, commonly alate with acute, extended ears. Sides oblique and sloping me- dially; anterior margin gently rounded to nasute. Surface sculpture variable from nearly smooth to moderately strongly costate; costae variable, numer- ous and closely crowded. Spines long and slender, thin clusters just anterior to ears; several on poste- rior margin and one on ear extremity; rare or non- existent on umbonal region and venter; few distantly scattered on trail slope. Brachial valve ex- terior obscurely costate and with posterior margin longitudinally wrinkled. Pedicle valve strongly convex in lateral profile, greatest curvature at narrowly humped venter; pos- terior region short and flattened, trail unusually long and fairly strongly convex. Anterior profile highly and narrowly domed, top of dome strongly rounded. Umbonal and visceral disc regions flat- tened and protruding only short distance posterior to posterior margin; trail somewhat abruptly bend- ing away from venter, long, convex, and steep ante- riorly. Sulcus evanescent, when present, usually appearing on venter, extending to anterior margin in some specimens but disappearing on trail in others. Trail in old or obese specimens developing narrowly rounded fold forming nasute anterior margin. Lateral slopes precipitate. Ears narrowly rounded, greatly extended. Brachial valve with visceral disc region moder- ately concave, deepest near midvalve; trail sharply geniculated from visceral region, long and thin, usually with several layers; trail zone including three or four layers, forming fairly wide band on edge of geniculated part. Ears concave, widely ex- tended, acute. Trail nasute in old specimens. Pedicle valve interior with sharply and narrowly elevated adductor platform. Ear baffles large, strongly corrugated toward inside of valve, usually extended anteriorly around inside margin as low ridge. Brachial valve with strong and thickened mar- ginal band hanging over long, steep trail; cardinal process flattened, trilobed; lateral ridges strong, uniting with strongly corrugated ear baffles. Adduc- tor platform consisting of two elongate, tear-shaped, elevated scars; breviseptum strongly elevated dis- tally; brachial ridges strongly thickened. Measurements (in mm).— brachial surface hinge mid- thick- length valve length length width width height ness USNM 705a 149800a 19.5 12.2 35.0 23.3 20.7 12.0 6.8 149800b 17.4 11.0 33.0 23.5 18.4 10.5 6.2 149800c 18.2 13.6 33.0 20.8 18.0 10.7 5.3 149800d 18.8 11.0 37.0 24.0* 17.8 12.0 6.8 (holotype) 149800e 13.8 ? 28.0 21.6* 16.9 9.4 ? 149800f 13.7 10.9 24.0 23.4* 16.3 8.7 4.2 149800g 18.0 ? 32.0 28.0 20.0 10.2 ? 149800h 12.6 ? 25.5 21.0* 15.1 8.7 ? 149800Í 14.6 11.0 27.5 18.0* 15.5 9.0 5.5 149800j 13.7 ? 27.0 19.7 15.5 9.0 ? 149800k 12.9 10.3 15.0 14.2? 14.1 8.7 ? 972 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Stratigraphic Occurrence.—Cibolo Forma- tion, Skinner Ranch Formation (Scacchinella beds at base = Decie Ranch Member). Localities.—Cibolo: USNM 728-1. Decie Ranch: 705a, 720e, 720g, 733r. Diagnosis.—Large, widely alate Kozlowskia hav- ing a rounded quadrate shell body. Types.—Holotype: USNM 149800d. figured paratypes: USNM 149799a, b; 149800b. Measured paratypes: USNM 149800a-c, e-k. Unfigured para- types: USNM 149800a, c, e-k. Comparisons.—This is a large species most like K. kingi Stehli from the lower Bone Spring Forma- tion in the Sierra Diablo. The pedicle valve of the Glass Mountains species has a bulbous body like that of K. kingi but it is rounder, the length and width of the body being nearly equal. A sulcus is not well formed in K. kingi and is usually present only on a part of the trail in K. alata (if present). The front margin of K. alata, in old specimens tends to form a narrow fold, a feature not seen in any specimens of K. kingi. The umbonal and vis- ceral regions of K. alata are more inflated than those of K. kingi. The brachial interiors of the two species are totally unlike in the development of their structures, those of K. alata being highly ex- aggerated. Discussion.—The tendency toward development of a nasute anterior appears to be a character thus far seen only in the Wolfcampian species. This tendency is very marked in old specimens of K. alata. An exceptional feature of this species is the pres- ervation of the trail anterior to the thickened mar- gin, a structure that is usually broken away in this genus. In one specimen the marginal ridge forms a band about 1.5 mm wide around the anterior mar- gin of the visceral disc and hangs over the trail, which is preserved for 7.5 mm, about half the valve length. Most of the other structures of the brachial valve in this species are strongly exaggerated but not thickened to the degree seen in some specimens of K. haydenenesis (Girty). Kozlowskia anterosulcata, new species Plate 313: figures 1-12 Small for genus, wider than long at hinge, ears widely extended and acute; sides sloping medially and anterior margin broadly rounded and gently emarginate. Surface sculpture variable, visceral re- gion with few fairly strong concentric wrinkles somewhat cancellated by radial costae. Costae fairly strong, broadly rounded, interspaces variable, usu- ally narrower than costae, about 6 costae per 5 mm, at front margin of well-preserved specimens. Spines few, arrangement uncertain because of poor pres- ervation. Pedicle valve unevenly and narrowly convex in lateral profile, posterior half flattened, anterior half of trail surface gently convex, venter strongly bent; anterior commissure forming high dome with rounded and usually slightly indented top. Visceral disc and umbonal regions moderately swollen but flattened and with long gentle slopes. Geniculation strong, taking place at venter, forming angle be- tween 45° and 65°. Sulcus originating on edge of visceral disc or venter, variable in strength, usually broad and moderately deep and extending to an- terior margin; flanks bounding sulcus rounded and steep-sided. Ears narrowly rounded in section. Brachial valve moderately concave and strongly geniculated; trail moderately long, fairly strongly cosíate. Ears well demarcated and flattened. Pedicle valve interior not known. Brachial valve interior with strong corrugated ear baffle and wide marginal band. Measurements (in mm).—Brachial valve length and thickness unmeasurable. surface hinge length length width midwidth height USNM 715 149795a 10.0 17.0 20.0* 12.9 5.4 149795b 11.3 21.0 20.0* 13.4 6.4? 149795c 10.7 19.0 19.4 12.7? 5.3 149795d 11.8 22.0 20.2 15.3 6.4 149795e 11.1 24.0 14.4 13.3 7.0? USNM 707j 149793a 11.8 21.0 18.4 13.8 6.4 (holotype) Stratigraphic Occurrence.—Lenox Hills For- mation. Localities.—USNM 707j, 712z, 715. Diagnosis.—Small alate Kozlowskia with flat- tened visceral area and sulcate trail. Types.—Holotype: USNM 149793a. Figured paratypes: USNM 149795a, b. Measured paratypes: USNM 149795a-e. Comparison.—This is a small and strongly alate species most resembling K. nasuta, new species. It is NUMBER 19 973 unlike that species in having a flattened visceral disc region, a somewhat angular geniculated zone, and the trail sulcate from visceral disc to anterior margin. Its ornament, flattened visceral disc, and smaller size help to distinguish it from the South American K. capaci (d'Orbigny). This is a rare species that has been found only in conglomeratic limestone with characteristic Wolf- campian cephalopods. Kozlowskia finlayensis, new species Plate 447: figures 49-55 Marginifera sublaevis R. E. King (part), 1931:89, pi. 23: figs. 13a-c [not figs. 15, 19 (= Anemonaria Ínflala Cooper and Grant, 1969)]. Fairly large for genus, transversely rectangular in outline, length equal to two-thirds width; cardinal extremities with large(?) ears; lateral margins rounded but sloping medially; anterior margin broadly rounded, medially indented; surface cov- ered by narrow costellae separated by spaces con- siderably wider than costellae; these best developed on the visceral disc region, becoming obsolete an- teriorly on trail; visceral disc region marked by strong concentric rugae crossing costellae to pro- duce subdued semireticulate pattern. Spines distant and scattered; broad row of 5 large spines on trail; smaller spines scattered over visceral region, on posterior margin, and on umbonal slopes. Pedicle valve unevenly and angularly convex in lateral profile, visceral disc region flattened, trail gently convex, angle of geniculation about 85°; anterior profile broadly domed. Umbo flattened, scarcely protruding above hinge; visceral region slightly swollen; cardinal extremities slightly de- flected in ventral direction; trail longer than visceral area, slightly convex and marked medially by sulcus originating at place of geniculation; sulcus narrow, moderately deep; anterior slope long and steep. Brachial valve moderately deeply concave, most concave in median region; sides sloping steeply medially; cardinal extremities flattened. Position of subperipheral marginal ridge visible as darkened band; trail anterior to subperipheral band moder- ately long. Measurements (in mm).—From King locality 512, YPM 11802 (lectotype) length 14.8, surface length 24.0, brachial valve length 12.4, hinge width 21.0*, midwidth 20.7, height 9.7, thickness 4.0?. Stratigraphic Occurrence.—"Leonard" Forma- tion (just below ammonoid bed). Locality.—King locality 512: Fossil Hill, north- west Finlay Dome, north of Finlay, Texas. Types.—Holotype: YPM 11802. Diagnosis.—Kozlowskia with angular lateral pro- file, well-ornamented visceral disc and strongly sul- cate trail. Comparison.—The lectotype is the only specimen of this species available for comparison with other species. It is most similar to K. kingi Stehli from the Sierra Diablo; indeed, King's cotype YPM 11796 belongs to this species. Several important dif- ferences between the two species appear, however, even at casual study. The lateral profile of Stehli's species is less angular than that of the Finlay Dome specimen, the former having a more inflated and more convex visceral region, although the two are similarly ornamented. The geniculation of K. kingi takes place more anteriorly, and the trail is never so strongly sulcate. Discussion.—The type lot of Marginifera sub- laevis King consists of seven specimens two of them belonging to the University of Texas and the others to Peabody Museum, Yale University. Two of the seven specimens are designated as cotypes and from these only the type must be selected. Specimen 11792a is selected and becomes Anemonaria sublaevis (R. E. King). Specimen T10051 is probably the same species. This leaves those still belonging to Kozlowskia without a name. Speciemen YPM 11796 belongs to K. kingi Stehli, and specimen T9954 is unidentifiable. Speci- men 11802 remains, without a name; for it we pro- pose K. finlayensis. Kozlowskia kingi Stehli Plate 313: figures 24-58; Plate 314: figures 21-45 Kozlowskia kingi Stehli, 1954:322, pi. 22: figs. 6-11. Marginifera sublaevis R. E. King (part), 1931:89, pi. 23: figs. 14a-c. Large for genus, strongly transverse with narrowly attenuated ears forming about 50° angle. Sides sloping medially; anterior margin broadly rounded to somewhat truncated, occasionally narrowly na- sute. Anterior commissure with slight median emar- gination. Beak small and incurved slightly over opposite valve. Surface faintly costellate, costellae best exhibited on venter. Spines few and scattered, 974 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY usually in row along posterior margin, few on flanks, scattered on trail. Ears usually smooth but occasion- ally with one or more spines. Pedicle valve unevenly convex in lateral profile; posterior or visceral region flattened to slightly con- vex; geniculated part narrowly rounded, forming angle of 45° to 50°; anterior part, or trail, gently convex; anterior profile squarely domed, with steep sides, ears protruding widely. Umbonal region flatly convex; region anterior to geniculation inflated. Trail long, occupying about two-thirds of surface length. Sulcus usually present, narrow, shallow, originating at anterior end of venter, where genic- ulation takes place 10 mm anterior to beak. Flanks rounded and steep. Brachial valve with posterior half of visceral re- gion moderately concave, this portion surrounded by steeply sloping trail. Ears prominent and nar- rowly rounded. Trail, when preserved, fairly long, not quite equal in length to length of visceral region. Pedicle valve interior with strongly fluted, well- elevated ear baffles extending laterally to midvalve, continuous around outside of visceral area as low ridge. Adductor track elevated, narrow. Brachial valve interior with small, sessile, typically marginiferid, cardinal process, low lateral ridges; ear baffles strong, fluted on outside, fluting extend- ing anteriorly to where baffle turns medially to form anterior marginal ridge; endospines long and prom- inent, reaching 3 mm at midvalve. Adductor scars consisting of two large inside scars and two smaller outside scars. Brachial ridges strongly developed. Trail covered by small, nearly prostrate spines. Measurements (in mm).— brachial surface hinge mid- thick- length valve length length width width height ness USNM 728f 149805a 18.3 30.0 28.3 21.4 11.7 149805b 15.7 28.0 28.5 22.0 10.8 149805c 15.3 25.0 20.2 20.2 8.7 149805d 16.5 29.0 31.5 25.0 10.6 149805e 16.2 c.27.5 27.6 23.5 9.5 USNM 728e 149803a 19.2 11.0 34.0 24.0 17.0 11.1 6.1 149803b 17.1 32.0 28.7 20.5 11.4 ? 149803c 13.7 26.0 23.2 16.9 8.9 ? 149803d 16.6 31.0 25.0 19.0 10.0 ? 149803e 12.6 10.5 22.0 20.0 17.9 7.8 3.8 Stratigaphic Occurrence.—Bone Spring For- mation (lower), Skinner Ranch Formation (lower). Localities.—Bone Spring: AMNH 497, 625, 628, 629, 631; USNM 725c, 728e, 728f, 728h, 742, 745, 746. Skinner Ranch: 716p. Diagnosis.—Large, alate Kozlowskia with sub- dued costellae and shallow sulcus. Types.—Figured hypotypes: USNM 149803a, d, f-o, q; 149805a, c. Measured hypotypes: USNM 149803a-e, 149805a-e. Comparison.—This species is the largest and most alate Kozlowskia so far described. It is most like K. alata, new species, but differs in its much wider outline, wider ears, and less bulbous form and umbonal region. Occasional specimens that have developed a nasute anterior suggest K. alata but they are unusual variants of K. kingi. Discussion.—This is one of the most abundant species in the lower Bone Spring of the Victorio Canyon region. It is also very well preserved in nearly all of its details. It is variable in the usual forms that productids take. Some specimens are narrower hinged, and there is variation in the de- gree to which the sulcus is developed. A few speci- mens, especially at USNM 728e, develope a nar- row, nasute fold at the anterior although this feature is rare. Considerable variability is noticed in the development of the spines. Some specimens have few spines, whereas others may develop a fair number of small spines, especially in the viserai disc region. The young are nearly flat and one of them has the characteristic attachment ring at the beak showing that this species, like many others, was fixed in its youthful stages. NUMBER 19 975 Kozlozvskia nasuta, new species Plate 313: figures 13-23 Medium size for genus; subquadrate outline, hinge widely extended, ears long, acutely pointed having angle about 60°. Sides nearly straight and sloping strongly medially; anterior margin fairly strongly rounded and medially, narrowly nasute. Surface costellate, costellae crowded, interspaces narrower than costellae, strongest on venter and trail, subdued on visceral disc, absent from umbo. Concentric wrinkles few on visceral disc. Spines few; one large spine near ear extremity; row of three spines at base of lateral slopes, with anterior- most one large and thick; body spines few and widely scattered; spines on trail few. Pedicle valve with uneven lateral profile, venter narrowly curved, visceral disc and umbonal regions short and flattened, trail moderately curved and long, much longer than visceral disc and umbo. Anterior profile moderately high, domed, with long, steeply sloping sides. Visceral disc and um- bonal regions moderately inflated, presenting flat- tened profile; not protruding strongly posterior to hinge. Median region strongly inflated, geniculation taking place about one-third distance from beak. Sulcus narrow, shallow, originating at beak but disappearing near front margin, at locus of narrow median fold, or siphon. Flanks inflated and steep sided. Brachial valve with costellae nearly obsolete on visceral disc region but stronger on trail; deepest near midvalve; ears moderately troughlike, demar- cated by low flexure toward pedicle side. Anterior with five trails forming moderately wide band. Pedicle valve interior with small and moderately thickened adductor platform; area on each side of beak and just anterior to posterior margin strongly granulöse; ear baffles strong, obliquely corrugated on inside. Brachial valve interior with small cardinal pro- cess; lateral ridges moderately developed, strongly granulöse on posterior side. Ear baffles strong, ex- tending into thick, long marginal ridge. Adductor platform widely divided, scars elongate, tear-shaped. Brachial ridges moderately developed. Endospines few, greatly elongated, measuring about 2 mm. Measurements (in mm).—Holotype USNM 149798: length 12.3 (Does not include length of si- phon, 1 mm), surface length 23.5, hinge width 19.1, width 15.5, height 7.6. Stratigraphic Occurrence.—Neal Ranch For- mation (Beds 9-14). Locality.—USNM 701a. Diagnosis.—Small, alate Kozlowskia with nasute anterior margin. Types.—Holotype: USNM 149798. Unfigured paratype: USNM 149798a. Comparison.—This is a distinctive species by virtue of its unusual nasute anterior and the pe- culiar development of the endospines. It is most like K. anterosulcata, new species, but differs in having a bulbous median region rather than an angular geniculation, a discontinuous sulcus on the trail terminating in a narrow fold, and fairly strong costellae. Inside the brachial valve it is unique for the great length of the endospines. It is smaller, more slender, and thinner-shelled than K. capaci (d'Orbigny), which has broader costae, a much more pronounced fold, and no development of the nasute anterior. Discussion.—Three specimens only are known of this species but its characters seem so positive and well defined that it is recognized as distinct. Kozlowskia subsphaeroidalis, new species Plate 314: figures 1-20 Small to medium size, usually wider than long, hinge forming widest part; ears prominent and greatly extended; sides sloping medially; anterior margin flattened to broadly rounded. Outline gen- erally subquadrate, usually slightly transverse. Sur- face sculpture variable, closely costellate, costae irregular in size, commonly obscure to obsolescent. Visceral disc region with distant concentric wrin- kles; ears with few wrinkles. Spines slender; those on sides and posterior generally stronger, arranged in row along posterior margin; tip of ear naked or with one spine; base of lateral slope with row of four halteroid spines; umbonal region and venter with scattered short, curved, erect spines. Trail with row of spines not far posterior to anterior margin. Pedicle valve unevenly convex in lateral profile, maximum curvature at venter, umbonal region strongly flattened, trail slope gently convex and long. Anterior profile forming steep-sided dome. Umbonal region flattened, with long gentle slopes 976 to lateral extremities. Angle of geniculation strong. Sulcus evanescent, usually not well developed but strong and extending from venter to margin in few specimens, but most lacking this feature. Ears long and narrowly rounded in section, acutely pointed and forming angle about 60°. Brachial valve moderately convex with well- demarcated ears; trails strong, final trail occasion- ally preserved. Trails numbering three or four. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Pedicle valve interior with moderately thickened adductor field; ear baffles strong, with strong corru- gations and continued anteriorly around inside of margin as low ridge. Brachial valve interior with small cardinal pro- cess, moderately developed lateral ridges, and mod- erately thickened adductor field. Ear baffles strongly corrugated and uniting with moderately developed marginal ridge. Brachial ridges indistinct. Measurements (in mm).— brachial surface hinge mid- thick- length valve length length width width height ness USNM711p 149797a 13.3 10.8 27.0 21.3 16.8 10.4? 5.9 (holotype) 149797b 12.6 10.7 25.5 18.4 16.2 8.3 5.4 149797c 13.2 10.1 26.0 17.2 15.7 8.5 5.0 149797d 11.9 9.2 21.0 17.4 14.2 7.2 5.0 149797e 12.6 9.2 23.0 16.4* 12.6 7.8 4.9 149797f 12.5 10.1 26.0 21.4* 16.0 8.0 4.6 149797g 12.5 10.1 23.0 20.0 15.0 8.0? 4.6 149797h 12.3 10.0 23.0 18.3 15.7 8.4 4.0 149797Í 11.4 9.0 23.0 15.8? 13.0 7.4 4.0 149797J 11.5 8.8 22.5 15.8? 13.2 7.7 5.0 149797k 10.2 8.3 21.0? 16.1 13.0 7.4 4.0 1497971 12.0? 9.8 20.0? 19.3 13.1? 6.8? 4.2 149797m 10.5 ? 21.0 17.7 12.7 7.0 ? 149797n 10.8 8.6 20.5 15.7 13.5 7.1 3.9 149797o 10.9 8.7 20.0 14.6? 12.8 7.0 3.6 Stratigraphic Occurrence.—Skinner Ranch Formation (Scacchinella bed in lower part). Localities.—USNM 705a, 71 lp, 716p, 724p, 719y, 724q. Diagnosis.-—Alate, transverse, nonsulcate Koz- lowskia with bulbous body. Types.—Holotype: USNM 149797a. Figured para types: USNM 149797b, k, p, q. Measured para- types: USNM 149797b-o. Unfigured paratypes: USNM 149797c-j, l-o. Comparisons.—This species is unlike K. alata and K. nasuta, both new species, in not having a tendency toward a nasute anterior margin even in old specimens. It differs from K. alata in size and in having a more transverse body. Its bulbous form separates it from K. anterosulcata, new species. It is readily distinguished from K. kingi Stehli in its smaller size, lack of a sulcus, and different orna- ment. It might be confused with K. capacii (d'Or- bigny) but is less transverse, more finely costellate, and has a rounder lateral profile. Kozlowskia species unidentified Several specimens of Kozlowskia are too poorly preserved to merit description. Species.—Specimen USNM 149814, from the Neal Ranch Formation at USNM 701, is a large brachial valve about 25 mm wide and 15 mm from the cardinal process to the anterior edge of the mar- ginal ridge. The anterior trail is missing except at the ears. The cardinal process is low and wide, the adductor platform fairly thick and the marginal ridge is strong. This valve suggests an exception- ally large species for this genus with its nearest relations to the larger varieties of K. splendens (Norwood and Pratten). NUMBER 19 977 Genus Hystriculina Muir-Wood and Cooper, 1960 Hystriculina Muir-Wood and Cooper, 1960:210.—Williams et al, 1965:H477. Small, transversely rectangular or subquadrate outline, hinge usually forming widest part in adults. Anterior commissure usually sulcate, sulcus usually narrow but variable in development and becoming obsolescent anteriorly in some species. Brachial valve deeply concave; visceral cavity usually thin. Surface costate except for smooth umbonal region, costae usually obsolescent, crowded and with nar- row interspaces. Surface sparsely spinose, spines all of halteroid type, rare along posterior margin, variable on ears and variously scattered on shell body; lateral spines usually long and stout; body spines generally shorter, curved and erect. Brachial valve without spines. Pedicle valve interior generally with somewhat thickened adductor field and fiabellate diductor scars. Ears usually concave and with variously de- veloped baffles. Brachial valve interior with variously developed lateral ridges, usually moderately strong, crossing ears as baffles and extended anteriorly to form sub- marginal ridge around sides and anterior, or dying out anterior to ears. Posterior platform usually not strongly developed and usually not strongly buttress- ing cardinal process; adductor field with smooth median scars on elevated, teardrop-shaped areas; outer scars small, nondendritic. Breviseptum thin, elevated anteriorly, reaching about to midvalve; brachial ridges variously developed. Anterior slope usually endospinose. Types-Species.—Hystriculina texana Muir-Wood and Cooper (1960:210, pi. 64: figs. 1-10). Diagnosis.—Small Marginiferinae with obsoles- cent costae, sparsely spinose and without a submar- ginal ridge or with only a moderately developed submarginal ridge. Comparisons.—Hystriculina may be confused with such other members of the Marginiferinae as Marginifera Waagen, Desmoinesia Hoare, Kozlow- skia Fredericks, and Elliottella Stehli. It differs from Marginifera in the nature of the external ornament, in not having the lateral spines arranged as in that genus, and in lacking the strong develop- ment of the margin as in the Asiatic genus. Des- moinesia resembles Hystriculina on the ventral side but has a spinose brachial valve. Kozlowskia is generally somewhat larger than most species of Hystriculina and generally is distinctly geniculated and more sparsely spinose than Hystriculina; it also possesses the distinctive trait of piling up trails anteriorly to form a thickened zone at the edge of the visceral disc, a feature never seen in Hystricu- lina. Elliottella may easily be confused with Hystri- culina but is generally more strongly costate, with the costae strong and deeply incised, a strong con- trast to the irregular and obsolescent development of the costae in Hystriculina. Another external differ- ence between the two genera is the fairly prominent concentric wrinkling seen on the visceral regions of both valves of Elliottella. Discussion.—Although Hystriculina is generally common in shaly faciès, it is somewhat restricted in its occurrence in the Glass Mountains. Con- sequently, the material for study is not as abundant as that of many other genera, and some features of this genus are not as clear as might be hoped. This fact and the general variability of the species make understanding difficult. One of the most important features is the subdued character of the radial ornament. Generally the umbonal region is smooth or nearly so but the re- mainder of both valves is covered by radial costae, variable in number and strength in each species, but constituting a good specific character except in ex- treme cases. Varices, or resting stages in growth, are more commonly conspicuous but variable wrinkles do not generally appear on either valve. The spines and their arrangement are usually variable within a species and also between species but they conform to the usually marginiferinoid pattern of few spines. Hystriculina usually has few spines on the posterior margin. The ears, up to mature adulthood, may lack spines; however, in some species the ears in young adults may bear a large terminal spine arising from the angle. In other species this spine may not form until late adulthood. Generally a row of spines may be de- tected along the base of the lateral slope as in many other marginiferoid genera. The body spines are extremely variable in number among and within species. Generally the genus can be described as sparsely spinose. The sulcus and, consequently, the fold are also variable. The genus may be said to be a sulcate form because a sulcus is invariably present on some part 978 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY of the median region of the shell. Usually the sulcus originates on or near the umbonal region and ex- tends to the anterior margin. Generally it is mod- erately deep and usually narrow and U-shaped. In H. ventroplana, new species, most specimens have the fold well developed near its origin at the um- bonal region and across the venter, but it gradually disappears in a general flattening of the trail a short distance posterior to the margin. A few specimens of H. sulcata, new species, which is normally strong- ly sulcate, also appear to lose the sulcus near the front margin. Inasmuch as the development of the fold depends on that of the sulcus, this is even more variable than the sulcus. Most specimens are provided with a low fold that originates near midvalve but its strength varies from barely visible to a strong subcarinate ridge. The pedicle interior furnishes few positive ge- neric characters. The adductor field is generally somewhat thickened but the diductor scars are seldom seen. The ear baffles are another variable feature; they are strong in some species but non- existent in others. The brachial interior does not offer distinctive generic characters, thus making generic determina- tion uncertain in the absence of the opposite valve or of the exterior. The marginal ridges are extremely variable, usually moderately to strongly developed, and, in such cases, commonly extended across the ears as striated baffles. In some, these extend anteriorly nearly to the front margin and then die out. More rarely these ridges extend to the front margin and then medially unite at midvalve to form a marginal ridge. A well-defined marginal ridge is rare and it never reaches the strength of that of Marginifera. Few immature specimens of Hystriculina were re- covered from the residues; consequently, little is known about the growth and development of the shell. The umbonal regions of the few young stud- ied indicate development in the manner common among the Marginiferinae, i. e., by the formation of an umbonal attachment ring and subsequent free- dom on the sea bottom (Grant, 1968). Hystriculina is common in the Pennsylvanian sediments of midcontinental United States. It is also fairly common in shaly parts of the Permian in the same region. In the Glass Mountains it is generally rare, and is found mostly in Wolfcampian sediments. Inasmuch as most of the etched material is derived from biohermal limestones, an environ- ment rare in the Pennsylvanian and Permian out- side of West Texas, the genus is rare in the collection. Most of the shale areas in the Glass Mountains are restricted and have been so fre- quently collected by so many paleontologists that they are now virtually exhausted. Hystriculina is commonest in the Neal Ranch Formation, where it is represented by the new species H. convexa, H. minima, and H. sulcata. The last-named species also occurs in the Uddenites-bear'mg Shale Member, which contains the species H. ventroplana, new species. In the goniatite bed of the Lenox Hills Formation H. dugoutensis (R. E. King) is a rare species. As with many other Wolfcampian types, Hystriculina ranges into the Skinner Ranch Forma- tion (basal Scacchinella bed), where it is repre- sented by H. pumila, new species. Hystriculina convexa, new species Plate 325: figures 1-24 About medium for genus, wider than long; trans- versely subrectangular in outline, hinge forming widest part; ears prominent, acute. Sides rounded and sloping medially; anterior margin broadly rounded to somewhat truncated. Surface irregularly costate, costae crowded, with narrow interspaces. Spines moderately long, stout on flanks, shorter and curved on body; one on ear in adults, about three in row at base of lateral slopes, and fairly numerous spines scattered on body of shell. Pedicle valve strongly convex in lateral profile, greatest convexity at venter, umbonal region some- what flattened. Anterior profile strongly domed and with steep sides, top slightly indented. Umbonal region narrowly and flatly convex; median region inflated, trail long and moderately convex. Sulcus originating on anterior side of umbonal region, variable, deepest in median part of trail, becoming obsolete at anterior in many specimens but reach- ing margin of others. Flanks inflated. Brachial valve most concave near midvalve, with moderately steep sides and anterior; umbonal region moderately deeply depressed; ears small and well demarcated by ridge; fold low, variable, usually poorly defined. Surface, costate and coarsely dim- pled, corresponding to spines of pedicle valve. Pedicle valve interior with strongly thickened NUMBER 19 979 Measurements (in mm).— brachial surface hinge mid- thick length valve length length width width height ness SNM701d 149764a 11.3 9.0 22.0 14.6 13.8 7.6 4.0 (holotype) 149765a 12.1 ? 23.0 16.5 15.5 7.0 ? 149765b 11.6 ? 22.0 16.0 14.4 7.5? Î 149765c 10.5 8.3 20.5 12.8* 13.5 6.6 3.6 149765d 11.1 8.4 20.0 15.0 12.8 6.9 2.7 149765e 10.5 8.0 19.0 13.8 13.0 6.3 3.6 149765£ 10.0 8.0 17.0 13.8* 12.3 5.5 2.2 149765g 8.4 7.0 13.0 8.0 10.5 4.5 1.8 149765h 8.1 7.2 12.0 6.6 9.7 3.3 1.5 149765Í 6.1 5.1 9.0 5.4 7.0 2.1 1.9 adductor field; ear baffles strong, forming decided ridge across ears in most specimens. Brachial valve interior with fairly strong lateral ridges joining strong baffles across ears, continuing anteriorly and medially as irregularly developed submarginal ridge. Cardinal process small. Adduc- tor scars moderately thickened, elongate. Brevisep- tum low; brachial ridges usually present, variously developed. Stratigraphic Occurrence.—Neal Ranch For- mation (beds 9-14), Lenox Hill Formation. Localities.—Neal Ranch: USNM 701, 701d, 701k, 712w, 715e. Lenox Hills: USNM 713y. Diagnosis.—Hystriculina of medium size with variable sulcus tending toward obsolescence ante- riorly. Types.—Holotype: USNM 149764a. Figured paratypes: USNM 149764b-d; 149765d, e. Measured paratypes: USNM 149765a-i. Unfigured paratypes: USNM 149765a-c, f, i. Comparisons.—This species is most comparable to H. sulcata, new species, in size and ornament. It differs in having a lesser development of the sulcus, that of H. convexa tending toward obsolesence and thus giving a convex appearance to the specimens. It is not as robust a species as H. sulcata, new species, and the spines tend to be more delicate than those of the latter. Furthermore, in the adult form, the umbonal region of H. convexa is lower and less extended posterior to the posterior margin than in H. sulcata. Hystriculina convexa shares the character of an- terior obsolescence of the sulcus with H. ventro- plana, a new species that does not attain the size of H. convexa and has the sulcus even less devel- oped. Hystriculina dugoutensis (R. E. King) Plate 445: figures 33-51 Marginifera dugoutensis R. E. King, 1931:87, pi. 21: figs. 6, 7. Small, transversely rectangular in outline, hinge forming widest part; ears moderately extended and generally acute; sides nearly straight, sloping medi- ally. Anterior margin broadly rounded, deeply in- dented. Surface costate, costae gently rounded, in- terspaces narrower than costae. Spines few, large: one on ear, row of three at base of lateral slopes, and few scattered spines on shell body. Pedicle valve with lateral profile strongly convex, most convex at venter; visceral and umbonal regions flattened. Anterior profile broadly domed, sides sloping steeply, median region deeply emargin- ated. Umbonal region narrow and rounded; sulcus Measurements (in mm).— surface hinge length length width ??iidwidih height USNM 715 YPM 11773a 10.0 16.0 16.4* 14.1 5.6? (Iectotype) 149754a 9.6 15.0 14.8 13.7 5.4? 149754b 9.6 15.0 14.5 13.0 5.0? 149754c 10.4 ? ? ? 3.0 YPM 11773b 9.8 15.0 ? 10.9 + 5.0? (paratype) 980 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY originating on umbonal region, narrow and deep, forming broad V; flanks swollen and narrowly rounded. Umbonal slopes to posterolateral extremi- ties steep. Brachial valve deeply concave, strong median fold originating near umbo. King (1931) described two specimens which are unlike in many particulars although both of them are stongly sulcate. The specimen chosen as lecto- type (YPM 11773a) is the wider of the two and is better formed. This has a deep V-shaped sulcus bounded by narrow flanks and is typical of the species as shown by the additional specimens col- lected by parties from the U.S. National Museum of Natural History. The paratype (YPM 11773b) has a more even lateral profile, with less flattening of the umbonal and visceral regions. In dorsal view the umbo of 11773b is strongly swollen and elevated far beyond the posterior margin. In 11773a, on the other hand, the umbo is low and very narrowly rounded and scarcely protrudes beyond the posterior margin. The sulcus of 11773b originates slightly farther anterior than in the other specimen, but is entirely different from that of the lectotype. In 11773a the sulcus is broad, deep, and somewhat V- shaped whereas in 11773b the sulcus makes a nar- row gash from umbo to anterior margin, and is shallow and U-shaped. The flanks bounding the sulcus of 11773b appear more inflated and less nar- rowly rounded, and the cardinal extremities are not preserved. Surface markings and spine arrangement are similar in the two. No other specimen like YPM 11773b was seen in the USNM material of this species. Inasmuch as the ornament, the sulcus, and the measurements indicate a specimen close to H. dugoutensis, this paratype is regarded as an aberrant member of this species. Straticraphic Occurrence.—Lenox Hills For- mation (Goniatite bed). Locality.—USNM 715. Diagnosis.—Strongly and deeply sulcate Hys- triculina, with strong fold on brachial valve. Types.—Lectotype: YPM 11773a. Figured para- type: YPM 11773b. Figured hypotypes USNM: 149754a-c. Measured hypotypes: USNM 149754a-c. Comparisons.—This is the most strongly sulcate Hystriculina known and is thus readily distinguish- able from described forms. Discussion.—This rare species was only found at the locality cited. Few specimens were taken and these are usually indifferently preserved, so it is difficult to obtain a whole specimen. Consequently, we are unable to give complete measurements. The information on the brachial valve was obtained from a complete specimen, partly filled with crystal- line calcite, which went to pieces during an attempt to excavate the brachial valve. Nevertheless, enough was obtained to understand that valve. Hystriculina minima, new species Plate 315: figures 1-23 Small, transversely subrectangular outline, hinge equal to widest part of adults; sides gently rounded, sloping medially; anterior margin gently rounded to nearly straight. Ears fairly large, nearly right angle or acute in adults. Surface costate; costae low, broadly rounded with narrow interspaces, often subdued and obscure, about seven per 5 mm at front, curved row of four at base of lateral slopes; distantly scattered spines on umbonal region, venter, Measurements (in mm).—Hystriculina minima, new species: brachial surface hinge length valve length length width midwidth height thickness USNM 701d 153898a 10.6 8.2 16.0 12.8 12.0 6.8 3.0 (holotype) 159773a 9.6 7.5 17.0 11.6 11.6 5.2 1.8 149773b 10.2 7.8 19.0? 11.0 11.5 6.1 3.6 149773c 8.9 7.2 16.5 16.5 10.9 5.2 2.2 149773d 10.2 7.8 20.0 14.0? 11.5 6.2 3.4 149773e 9.0 7.3 16.0 12.4? 10.7 5.4 2.0 149773f 11.0 8.8 20.5 13.0? 12.8 6.0 3.0 NUMBER 19 981 and trail. Ears and posterior margin lacking spines. Pedicle valve fairly strongly convex in lateral profile, most convex in posterior half; anterior pro- file steep-sided dome with well-rounded crest. Urn- bonal region narrowly swollen and protruding moderately posterior to posterior margin; median region inflated; sulcus usually not developed, but if present, shallow and inconspicuous, not reaching anterior margin. Flanks rounded. Brachial valve fairly and evenly concave, deepest at midvalve and surrounded by steep slopes. Um- bonal region deeply depressed. Ears demarcated by oblique flexure, gently concave. Costae usually ob- scure. Pedicle valve interior with adductor scars on mod- erately swollen platform. Ear baffles not developed. Brachial valve interior with fairly large erect car- dinal process (for small shell); adductor scars on moderately thick platform, elongate, teardrop- shaped. Lateral ridges not developed; ear baffles low and inconspicuous; endospines in narrow band on venter; trail slope costate and granulöse. Stratigraphic Occurrence.—Neal Ranch For- mation (Beds 2-14 of P. B. King). Localities.—USNM 701, 701a, 701a1, 701a3, 701c, 701d, 701h, 721g. Diagnosis.—Small and compact Hystriculina with poorly developed fold and sulcus. Types.—Holo type: USNM 153898a. Figured paratypes: USNM 149773d, f; 153898b-d. Measured paratypes: USNM 149773a-f. Unfigured paratypes: USNM 149773a-c, e, g. Comparisons.—This is a small species comparable to H. pumila, new species, from which it differs in its less regular costation, lesser development of a sulcus, and more rounded outline. It is also smaller than H. ventroplana, new species, and does not have the sulcus confined to midvalve as in that species. Hystriculina pumila, new species Plate 315: ficures 24-47 Small, wider than long, transversely subrectangu- lar outline; hinge widest part of adults; sides gently rounded; anterior margin nearly straight, slightly indented medially; anterolateral extremities nar- rowly rounded. Ears fairly large, forming acute angle in adults. Surface marked by closely crowded, broadly rounded costae, variable in size and strength of development (possibly a funtion of preservation). Costae of large adult numbering 8 or 9 on flanks and 4 in sulcus. Spines numerous, all of halteroid type; a sparse row on posterior margin and angle of ear, a curved row at base of lateral slope, and numerous spines scattered over umbonal region, venter, and trail. Body spines generally erect, curved anteriorly, usually short, attaining length of 5 or 6 mm; lateral spines longer and stouter, approaching 10 mm in length. Pedicle valve moderately convex in lateral pro- file, maximum curvature in posterior third, um- bonal region slightly flattened; anterior profile domed with steeply sloping sides and medially in- dented top. Umbonal region moderately inflated and moderately protuberant posterior to posterior margin. Posteromedian region strongly inflated; trail long and convex. Sulcus originating on venter, Measurements (in mm).—Hystriculina pumila, new species: USNM 71 lp 149759a 149759b (holotype) 149759c 149759d 149759e 149759f 149759g 149759h 149759Í 149759J brachial surface hinge length valve length length width midwidth height thickness 10.6 8.2 20.0 13.2 12.7 5.9 2.8 10.1 7.7 19.0 12.6 11.7 5.9 2.7 9.7 7.6 18.0 11.4 11.2 5.7 2.3 9.2 7.5 16.0 12.2? 11.8 5.3 2.2 9.2 7.4 17.0 11.7 11.0 5.0 2.5 8.1 6.3 15.5 10.5 9.5 4.7 2.0 7.7 6.4 14.0 8.8 9.1 4.9 1.6 7.4 ? 11.5 9.0 9.2 3.7 ? 6.8 ? 10.5 6.5 7.7 2.8 ? 6.2 5.6 9.0 6.2 6.8 2.8 1.1 982 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY shallow and narrow, occupied by two to four costae; flanks bounding sulcus well rounded and with steep sides. Ears triangular, gently convex. / Brachial valve deeply and fairly evenly concave, deepest medially, with strongly sloping sides and front; ears well demarcated by oblique ridge; fold low and inconspicuous, originating near midvalve. Surface costate and indented by dimples corre- sponding to spines of pedicle valve. Pedicle valve interior with small development of adductor platform and poorly formed ear baffles. Brachial valve interior with fairly strong lateral ridges extending anterolaterally to form low baffles across ears and continuing anteriorly to form in- distinct submarginal ridge. Cardinal process small, on moderately developed posterior platform. Me- dian adductor pair consisting of tear-shaped marks moderately thickened and elevated. Breviseptum low; brachial ridges moderately developed. Stratigraphic Occurrence.—Skinner Ranch For- mation (lower). Localities.—USNM 707w, 71 lp, 712p, 715v, 719y, 724p, 724q. Diagnosis.—Small Hystriculina with strong costae and moderately developed sulcus. Types.—Holotype: USNM 149759b. Figured paratypes: USNM 149759c, j-n. Measured para- types: USNM 149759a, c-j. Unfigured paratypes: USNM 149759a, d-i. Comparisons.—This species is compared with H. minima, new species, the species most like it, under that heading. The strong and fairly constant costae make the species unique in this genus. This is the youngest species of Hystriculina known in the Glass Mountains. Hystriculina sulcata, new species Plate 233: figures 1-39 fMarginifera wabashensis R. E. King (not Norwood and Pratten), 1931:91, pi. 23: fig. 4. About maximum size for genus, wider than long, maximum width usually at hinge; transversely sub- rectangular in outline; sides gently rounded and sloping medially; anterior margin broadly rounded and narrowly indented medially. Ear small, nar- rowly rounded in section, bluntly pointed but usually forming slightly acute angle. Surface orna- ment variable, consisting of faint, subdued costae, Measurements (in mm).—Hystriculina su Icata, new species: brachial surface hinge length valve length length width midwidth height thickness USNM 701 149718a 12.3 9.4 22.0 16.7 14.7 8.4 ? 149718b 11.9 9.5 21.0 15.7 15.4 7.8 2.8 (holotype) 149718c 12.8 9.7 23.0 15.6 14.7 8.0 2.4 149718d 12.2 9.5 23.5 16.0 14.9 7.9 3.5 149718e 12.0 8.3 23.0 14.4 13.9 7.8 2.1 149718Í 10.5 7.7 18.5 14.6 13.4 6.7 3.0 149718g 10.5 ? 17.5 13.6? 13.6 5.4 ? 149718h 9.0 7.4 15.0 12.8 11.7 5.0 1.8 149718Í 8.3 6.8 12.5 11.7 11.7 4.1 0.6 149718j 8.1 6.5 12.0 8.4? 10.0 3.3 1.0 149718k 5.9 4.9? 8.0 7.0 7.9 2.4 1.2 1497181 12.5 9.6 23.0 16.0 15.7 8.6 3.1 149718m 11.9 8.7 23.0 15.9 14.6 8.1 3.5 149718n 12.8 9.3 23.0 15.5 14.7 7.5 3.1 149718o 13.2 ? 26.0 18.2 16.2 6.8 ? USNM 701-1 149724a 15.3 11.0 30.0 21.0 17.8 10.8 4.2 149724b 12.8 9.4 24.0 17.2 14.9 7.7 3.7 149724c 11.3 9.4 19.5 15.0 14.4 6.6 2.8 149724d 11.9 ? 23.0 15.8 14.7 6.5 ? NUMBER 19 983 broadly rounded, and with narrow spaces between costae. Spines wholly halteroid, few in number; two on lateral slope over ear and others scattered dis- tantly on umbonal region, venter, and trail. Ears and posterior margin spineless. Pedicle valve strongly convex in lateral profile, venter most strongly curved, umbonal region some- what flattened. Anterior profile strongly elevated, domed; deeply indented medially flanks well rounded, sides steep. Umbonal region flatly convex; median region inflated. Sulcus originating on an- terior side of umbonal region, narrow and contin- uous to anterior margin. Umbonal region low, not extending conspicuously posterior to posterior mar- gin. Brachial valve deepest medially and divided lon- gitudinally by low, rounded fold originating poste- rior to mid valve. Ears flatly concave and with margins elevated, demarcated from concave area by oblique ridge. Slopes to midvalve steep. Pedicle valve interior with adductor callosity on posterior of median ridge, in old shells forming platform expanding in width anteriorly. Ear baffles not well developed. Brachial valve interior with small, stout cardinal process on moderately developed posterior platform; lateral ridges low, oblique extending anterolaterally to meet ear baffles; submarginal ridge present only in old shells, extending from externally stri- ated ear baffle anteriorly and medially. Breviseptum short; brachial ridges moderately developed. En- dospines short and stout, scattered on anterior slope. Stratigraphic Occurrence.—Gaptank Forma- mation (Uddenites-bedLring Shale Member), Neal Ranch Formation (beds 2, 4, 9-14 of P. B. King), Lenox Hills Formation, possibly also Hess Forma- tion. Localities.—Gaptank: USNM 715z. Uddeniles: USNM 701e, 70If, 701p, 701q, 701 r, 701t, 701v, 702q, 703p, 705h, 713a. Neal Ranch: USNM 701, 701c, 701 d, 701k, 701-1, 727e. Lenox Hills: USNM 704f, 704r?, 707m, 709t, 716r. Hess?: USNM 719q. Diagnosis.—Strongly sulcate, subquadrate Hystri- culina. Types.—Holotype: USNM 149718b. Figured paratypes: USNM 149718-1, n-p; 154235b, e, f. Measured paratypes: USNM 149718a, c-o; 149724a- d. Unfigured paratypes: USNM 149718a-k, m; 154235a, c, d. Comparisons.—This is a fairly large species and, therefore, should be compared to H. ventroplana and H. convexa, both new species, and H. dugout- ensis (R. E. King). Distinction between this species and H. ventroplana is easy because the sulcus of the latter becomes obsolescent anteriorly in the adult and its costae are less strongly devel- oped than in H. sulcata. Comparison with H. con- vexa is made under that species. Hystriculina texana Muir-Wood and Cooper is strongly sulcate in most of its specimens although it is variable. It is a much wider and generally smaller species and has a lower umbonal region than that of H. sulcata. Hystriculina dugoutensis (R. E. King) is much more strongly sulcate and proportionately wider than H. sulcata and has narrowly rounded flanks. The two species are en- tirely unlike. Hystriculina ventroplana, new species Plate 315: figures 48-72 Small, slightly wider than long, subquadrate out- line; hinge usually slightly wider than midwidth; ears small, slightly acute. Sides gently rounded, slop- ing slightly medially. Anterior margin moderately and broadly rounded. Surface obscurely costate, costae subdued and irregular, worn specimens sug- gesting smooth shell. Spines few in number; three on lateral slopes over ears, rest scattered on shell body; one spine on ear extremities in adults. Pedicle valve strongly convex in lateral profile, greatest curvature near venter, umbonal region flattened. Anterior profile high, steep-sided dome with gently rounded crest. Umbonal region broad but flatly convex, protruding conspicuously poste- rior to hinge. Median region inflated; trail long and gently convex. Sulcus inconspicuous, originating on venter but merging with trail surface anteriorly and, in adults, not visible near front margin. Flanks rounded and steep-sided. Brachial valve deeply concave, maximum cur- vature near midvalve; anterior and sides steeply dipping toward midvalve. Ears flattened and well demarcated by low ridge. Fold low, poorly de- veloped. Pedicle valve interior with small adductor plat- form moderately thickened; ear baffles poorly de- veloped, interior strongly striated anterior to ear. 984 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOG? Brachial valve interior with fairly large cardinal process, strong lateral ridges and ear baffles extended anteriorly nearly to front margin; adductor field moderately thickened. Measurements (in mm).—Brachial valve length unmeasurable, except USNM 149777b, 9.2. USNM 701v 149785a 149785b USNM 701q 149783a 149783b 149783c 149783d 149783e 149783f USNM 701e 149780a USNM 701 149777b (holotype) length 11.8 12.0 11.7 10.9 11.5? 11.6 11.3 11.4 10.7 11.8 sur- face hinge mid- thick- length width width height ness 21.5 21.0 15.0 13.0 14.2 12.7 6.9? 6.8? ? 20.0 13.9 12.2 6.7? ? 20.0 13.1 12.6 7.0? ? 21.5? 14.6 13.3 5.8? ? 21.5 14.1 13.0 7.7? ? 20.5 13.7 12.7 6.7? ? 21.0 13.6* 12.5? 7.4? 3.1 20.5 12.8 12.3 6.2 ? 23.0 12.8 13.3 7.8 3.0 Stratigraphic Occurrence.—Gaptank Forma- tion (Uddenites-bearing Shale Member) Neal Ranch Formation (beds 2, 9-14 of P. B. King). Localities.—Uddenites: USNM 701e, 701p, 701q, 701v, 701y. Neal Ranch: USNM 701, 701a, 715b, 719r. Diagnosis.—Subquadrate Hystriculina with in- conspicuous sulcus at midvalve but no sulcus on anterior part of trail. Types.—Holotype: USNM 149777b. Figured paratypes: USNM 149777a-c; 149783a, b. Measured paratypes: USNM 149780a; 149783a-f; 149785a, b. Unfigured paratypes: USNM 149780, 149783c-f, 149785a. Comparisons.—This species is readily dis- tinguished from all described Hystriculina by the subdued ornament and the obsolescence of the sulcus anteriorly, although it may be fairly strong at midvalve. Subfamily COSTISPINIFERINAE Muir-Wood and Cooper, 1960 Marginiferidae with crenulated ridges extending across the ears of both valves; prominent endospines in row anterior to septum, and also a set on outer margin of brachial ridges; adductors smooth or rarely partly dendritic. Genera in West Texas: Costispinifera Muir- Wood and Cooper, 1960; Bothrionia, new genus; Elliottella Stehli, 1954; Echinauris Muir-Wood and Cooper, 1960; Oncosarina Cooper and Grant, 1969. Two of the five genera are abundantly represented in the Glass Mountains, Elliottella is abundant in the Sierra Diablo but Bothrionia and Oncosarina are rare. Bothrionia is known only from Guadalu- pian strata in the Guadalupe and Glass Mountains, in both of which it is rare. Oncosarina is fairly com- mon and characteristic of the upper part of the Skinner Ranch Formation in the Glass Mountains. Costispinifera, characteristic of the Early Guadalu- pian, is common in the Glass Mountains but rare in the Guadalupe Mountains. Elliottella, which char- acterizes the Skinner Ranch in the Glass Mountains and its correlative in the Sierra Diablo is common in the latter but rare in the Glass Mountains. Liosotella Cooper which had hitherto been placed in this family is now known to possess a zygidium and has been transferred to the Paucispiniferidae. Nudauris Stehli is here referred to the Dictyoclos- tidae. Bothrionia, new genus [Greek bothrion (little pit)] Small, transverse and wide-hinged Marginiferidae, deeply concavo-convex; anterior margin strongly nasute, giving shell subtriangular outline when well preserved. Surface costellate, costellae narrow, discontinuous in some specimens. Surface sparsely spinose; few spines on the posterior margin, large one near angular extremity of each ear, row at base of lateral slopes, scattered spines on visceral disc and trail, especially on anterior part of latter. Sul- cus inverting to fold anteriorly. Pedicle valve interior with ear baffles moderately to strongly developed, continued anteriorly to form ringlike ridge around visceral area. Muscle scars lightly impressed; no adductor platform. Brachial valve interior with strong oblique lat- eral ridges extending anterolaterally from cardinal process; ear baffles inconspicuous or not developed. Cardinal process sessile, trilobed but without zygi- dium. Posterior platform strongly developed in old shells and extended anteriorly to separate adductor scars and partly enclose proximal part of brevi- septum. Adductor scars four in number, one pair NUMBER 19 985 median but other two on outside of inner ones; scars small, median scars narrowly oval and not lobed. Breviseptum slender blade, free distally. Brachial ridges strong and narrowly looped. Endo- spines numerous, long and slender. Type-Species.—Boihrionia nasuta, new species. Diagnosis'.—Nasute Marginiferidae with sulcus reverting to a fold in the pedicle valve and a strong marginal rim around the visceral region of the pedicle valve. Comparisons.—No described genus is quite like this one externally, but Paramar ginif era Fredericks from the Permian of the Urals has an interior mar- gin in the pedicle valve like that of Boihrionia. The exterior of Paramar ginif era, however, with its fine costellae, long, nonsulcate trail, and different spine arrangement, is entirely unlike the Glass Moun- tains genus. Haydenella Reed from the Permian of the Salt Range of Pakistan is also similar, having in com- mon the narrow visceral cavity and a row of spines along the base of the lateral slopes. This genus is also costellate and nonsulcate; consequently, it can- not be confused with Boihrionia. Rugivestis Muir-Wood and Cooper is a somewhat exaggerated form having essentially the characters of Bothrionia but its brachial valve interior is not wholly known. In Rugivestis the umbonal and vis- ceral regions are reticulated, and the sulcus is short and reverts to a fold at the anterior. The "nose" at the anterior, instead of being like that of Bothri- onia, is elevated, elongated, and carinate but does not protrude beyond the front margin, as in Bothrionia. The interior of Rugivestis, like that of Bothrionia, is provided with a thickened rim around the visceral disc of the pedicle valve. The brachial valve of the Oregon genus appears to have been delicate but other features are not known. The two genera are unlike in detail but are certainly related and should be assigned to the same family. Productus subpusillus Licharew (1937:40, 107, pi. 3: figs. 7-13) from the "Upper" Permian (P2) of the North Caucasus belongs to this genus. Licha- rew's figure 7 shows a fine and typical brachial valve interior. Discussion.—Bothrionia is rare in the Glass and Guadalupe mountains. Although the material at hand is adequate for description and illustration, it does not provide a good growth series, and the num- ber of brachial valves is small. The full range of variation of inner and outer details is thus not avail- able. The unusual feature of the exterior is the sulcus, which originates on the venter, extends for about half the valve length, and then abruptly reverts to a narrow fold that is extended anteriorly beyond the anterior margin as a semitube. This nasute pro- jection thus gives the exterior a definitely triangular outline. The interior of the pedicle valve is unusual in the light impression of the muscle field and the lack of an adductor platform. The most pronunced fea- ture of the pedicle valve interior is the strong rim around the inside of the visceral cavity. As in many other productids the bases of the exterior spines, especially of the lateral rows, is extended into the interior. The brachial valve is distinctive for the great de- velopment of long and slender strainer spines. They occupy a broad band at the place of geniculation, and extend for some distance down the slope of the trail. The cardinal process is small and typically mar- giniferid but has no supporting zygidium. It and the midvalve are greatly thickened by the forma- tion of a posterior platform anterior to the cardinal process. This platform is extended laterally along the inside of the lateral plates and anteriorly be- tween the adductor pairs to enclose the posterior end of the breviseptum. The brachial ridges do not extend directly laterally but are given off obliquely toward the anterolateral extremities. In one specimen the inner end of the loop is thickened and elevated. Bothrionia guadalupensis, new species Plate 316: figures 27-51 Subtriangular to narrowly semielliptical outline, sides sloping rapidly medially, anterior margin broadly rounded to nasute, depending on age. Ears large, subalate, acutely pointed. Surface marked by irregular subdued, closely crowded costae, 3 to 5 per 5 mm on slope of trail. Spines as usual for genus. Pedicle valve moderately convex in lateral profile, umbonal region abruptly curved, venter and trail forming long, convex, and moderately steep slope; anterior profile narrowly domed, sides steeply slop- 986 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY ing. Sulcus poorly defined, narrow and shallow, originating just anterior to umbonal region but dis- appearing about one-quarter valve length posterior to anterior margin; flanks swollen and steep-sided. Anteromedian extremity drawn into narrow tube- like fold, not preserved in young specimens. Brachial valve deeply concave with steeply slop- ing sides and anterior; ears concave and well de- marcated. Fold scarcely defined. Pedicle valve interior with thickened rim around visceral cavity deeply inset with long rim on sides and front. Muscles lightly impressed. Brachial valve interior with high, thin breviseptum and very long endospines on trail slope. Measurements (in mm).—From locality USNM 728, specimens 149628a and d (holotype), respec- tively: length 17.6, 14.1; brachial valve length (?), 11.5; surface length 30.3, 21.0; hinge width 21.6, 17.8; midwidth 19.6, 17.4; height 9.5, 7.4; thickness (?), 3.4. Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Member). Localities.—AMNH 512, USNM 728. Diagnosis.—Large, transverse Bothrionia with large ears, subdued costae, and a large visceral cavity. Types.—Holotype: USNM 149628d. Figured paratypes: USNM 149628a-c, e, f. Measured para- types: USNM 149628a. Comparisons.—Because of its size and trans- verse form, this species is directly comparable to B. transversa, new species, from the Glass Mountains but is totally unlike B. pulchra, new species, the only other species from the Guadalupe Mountains. It differs from B. transversa in the less prominent ribbing, the slighter development of the sulcus, and the less inflated umbonal region. Bothrionia sub- pusillus (Licharew) appears to be a somewhat smaller species and still more transverse. Bothrionia nasuta, new species Plate 316: figures 1-26; Plate 317: ficures 1-10 Productus texanus R. E. King (not Girty), 1931:89, pi. 23: fig. 7. Small, subtriangular to semielliptical outline; widest at hinge, commonly alate; ears large, usually acute; sides gently rounded, sloping strongly me- dially. Anterior margin, when complete, narrowly nasute, drawn to small half tube, or trough. Surface irregularly costate, costae subdued, frequently dis- continuous, numbering three to four per 5 mm on trail. Spines slender, full length not known: one on each ear near distal angle; row of three at base of lateral slopes; horizontal row on trail at about level of anterior end of sulcus; scattered small and delicate spines on visceral disc and trail rarely pre- served. Pedicle valve with fairly even lateral profile, ven- ter strongly convex, posterior third somewhat less so, anterior third or trail gently convex. Anterior Measurements (in mm).—Bothrionia nasuta. new species: brachial surface hinge length valve length length width midwidth height thickness USNM 706b 149637a 15.5 13.0 25.0 17.2 15.3 8.1 3.2 (holotype) 149637b 14.5 ? 25.0 16.2 14.0 7.8 2.9 149637c 13.3 11.2 21.0 15.6? 14.4 7.0 2.9 149637d 14.1 ? 24.0 16.0 14.3 7.9 ? 149637e 13.3 10.9 22.0 15.7 14.5 7.0 2.6 149637f 11.5? 9.0 18.0 16.7 13.9 5.8 1.8 149637g 12.8 ? 20.0 16.8 14.9 6.1 149637h 15.2 ? 26.0 19.5 16.7 7.8 USNM 713 149639 16.2 ? 24.0 16.8 14.9 8.2 USNM 706 149635a 15.4 ? 25.0 18.1 16.2 8.0 159635b 16.0 ? 30.0 18.8 15.6 8.4 159635c ? ? ? 18.1 ? ? 2.9 NUMBER 19 987 profile broadly domed, with sloping sides. Beak small; umbonal region swollen moderately, not pro- jecting far posterior to posterior margin. Sulcus shallow, originating on anterior slope of umbonal region and extending anteriorly part way on trail, then ending abruptly in flattened area, becoming narrow trough at anterior margin. Costellae bound- ing sulcus commonly sloping medially to terminate on anterior part of sulcus; one or two costellae in sulcus, but arrangement not regular. Anterior mar- gin of trail forming band with closely crowded cos- tellae. Flanks bounding sulcus moderately rounded, lateral slopes steeply inclined. Ears broad, com- monly alate, gently convex. Brachial valve delicate and thin, fitting closely into concavity of pedicle valve, thus forming thin visceral cavity. Maximum concavity at midvalve. Umbonal region deeply concave; fold originating near posterior quarter and occupying about median one half; anterior extremity probably with nar- row trough (not preserved) Ears broad and con- cave, defined by broad, oblique flexure. Sides and anterior steeply sloping. Costellae more subdued than on pedicle valve. Pedicle valve interior with small, narrowly and transversely elliptical diductor scars. Adductor scars inserted in pit in thickened specimens; ear baffles moderately strong but continued around margin of visceral disc as thick ridge. Inner spines prominent. Brachial valve interior with moderately thick- ened posterior platform; small cardinal process and small adductor scars. Endospines long, slender, and forming thick band. Stratigraphic Occurrence.—Word Formation (China Tank and Willis Ranch members and lens above the latter). Localities.—China Tank: USNM 706c, 713, 726r. Willis Ranch: USNM 706. Lens: USNM 706b. Diagnosis.—Small, compact, triangular Bothri- onia with strong costae, midwidth and length nearly equal. Types.—Holotype: USNM 149637a. Figured par- atypes: USNM 149635a, b, 149636a, b, 149637b, f, 149639, 153845. Measured paratypes: USNM 149635a-c, 149637b-h, 149639. Unfigured paratypes: USNM 149637c-e, g, h. Comparisons.—This species is similar in form and outline to B. pulchra, new species, but the Guada- lupe species is less strongly costate, the ears are more accentuated by steeper umbonal slopes, and the ears are enclosed on the outside by a prominent ele- vation. The other described species from Texas are larger and relatively more transverse than B. nasuta. Bothrionia pulchra, new species Plate 317: figures 11-18 Shell small, subtriangular outline, hinge forming widest part; anterior margin narrowly nasute. Sides slightly convex and sloping strongly toward middle. Umbonal and visceral disc regions costate, costae made nodose by rounded spine bases; trail marked by closely crowded costae forming band around an- terior half. Spines one on each ear, row of three at base of lateral slopes, band around midvalve just posterior to costate band of trail. Pedicle valve moderately convex, umbonal region somewhat flattened but more abruptly bent from venter, trail gently convex, forming long steep slope. Sulcus narrow and shallow, occupying midvalve, passing anteriorly into narrow half tube projecting anterior to margin. Flanks rounded and steep; mid- valve strongly swollen. Ears flattened and well de- marcated from precipitous umbonal slopes. Brachial valve deeply concave, umbonal and vis- ceral regions forming circular depression, deepest medially; sides short, sloping moderately; ears with elevated outer rim, demarcated on inside by abrupt descent to midvalve. Surface completely costate and with dimples in interspaces except on part cor- responding to closely and regularly costate trail. Fold narrow but obscure. Pedicle valve interior with lightly developed rim around visceral region. Brachial valve interior un- known. Measurements (in mm).—From locality USNM 732, holotype 149631: Length 14.2, brachial valve length 11.0, surface length 22.0, hinge width 16.6, midwidth 15.4, height 7.5, thickness 2.2. Stratigraphic Occurrence.—Cherry Canyon Formation (Getway Member). Localities.—AMNH 496, 519, 600; USNM 730, 732. Diagnosis.—Small, triangular Bothrionia with short sulcus and strongly nasute anterior but costae not strong. Types.—Holotype: USNM 149631. Figured para- type: USNM 149630. Comparison.—This species in size and shape is 988 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY similar to B. nasuta, new species, but it is less strongly costate than the Glass Mountain species. Its sulcus is somewhat shorter than that of B. nasuta and the narrow, troughlike fold of the an- terior margin is longer although it does not pro- trude beyond the anterior margin any farther than in B. nasuta. The ears of B. pulclira are more prominent than those of B. nasuta because the umbonal slopes of the former are steeper and the surface of the ear is depressed along the bases of the umbonal slopes. Bothrionia transversa, new species Plate 317: ficures 19-54; Plate 318: figures 27-57 Marginifera? texana R. E. King (not Girty), 1931:89, pi. 23: figs. 5-7. Large for genus, wider than long, outline semi- elliptical to subrectangular. Ears large, commonly alate. Sides sloping medially; anterior margin gen- tly rounded to subnasute. Surface irregularly costate, costae variable in size, ranging from three to four per 5 mm on median level of trail. Spine arrange- ment as described for genus. Pedicle valve moderately convex in lateral profile, posterior third gently convex, anterior third form- ing moderately sloping trail; venter swollen and narrowly convex. Sulcus poorly defined, shallow, orginating on posterior side of venter and terminat- ing posterior to anterior margin in broad, flattened band of finer and crowded costellae. Flanks rounded, not prominent; lateral slopes fairly steep. Brachial valve concave, sides short; deepest me- dially, ears set off by oblique fold. Fold inconspicu- ous. Brachial ornament subdued. Pedicle valve interior with small ear baffles and lightly developed ridge around visceral area. Mus- cle field slightly impressed. Brachial valve interior generally delicate but strongly thickened in old shells. Curvature moder- ate, and posterior platform moderately thickened, except in old shells. Endospines numerous and long. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 715i 149646a 16.3? ? 26.0 22.4 19.0 8.2 ? 149646b 15.9 13.1 27.0 22.1 19.6 9.0? 4.0 149646c 15.1 ? 23.5 21.9 19.7 6.6? ? 149646d 14.2 ? 24.0 21.9 17.8 7.0 ? 149646e 14.3 ? 24.0 21.3 16.9 7.6 ? 149646f 13.1 ? 21.0 21.6 17.4 6.8 ? 149643 16.4 12.0 25.0 21.9 19.3 8.5 3.0 (holotype) USNM 706b 149641a 16.9 ? 27.5 22.0 18.9 8.9 ? 149641b 15.0 ? 25.0 22.3 18.6 8.0 ? 149641c 14.1 11.8 23.0 22.3 18.7 7.2 ? 149641d 13.3 11.5 22.0 20.7 17.4 7.1 ? Stratigraphic Occurrence.—Word Formation (Willis Ranch and Appel Ranch members and lens between them). Localities.—Willis Ranch: USNM 706e. Lens: USNM 706b. Appel Ranch: USNM 715i, 719z, 722t, 727j. Diagnosis.—Widely transverse Bothrionia with strong and sharply incised costae. Types.—Holotype: USNM 149643. Figured para- types: USNM 149641a, c; 149646b, e, h; 153846; 153848a-e; 153849a-c; 153850a, b. Measured para- types: USNM 149641a-d, 149646a-f. Unfigured paratypes: USNM 149641b, d; 149646a, c, d, f, g. Figured specimen: YPM 11733. Comparison.—Of described species this one can be compared to B. guadalupensis, new species, which is also strongly transverse. The Glass Mountains species is more strongly ornamented and the re- NUMBER 19 989 lationship of midvalve to length shows the species to be more transverse at midvalve than the Guada- lupe species. Genus Costispinifera Muir-Wood and Cooper, 1960 Costispinifera Muir-Wood and Cooper, 1960:217.—Williams et al., 1965:H479. Small, length and width nearly equal, deeply concavo-convex, subquadrate outline; hinge wide, generally forming greatest shell width; anterior com- missure slightly uniplicate. Visceral cavity deep. Both valves intricately wrinkled in young stages but finely costate in adults. Halteroid spines prominent on ears; ornament spines scattered over whole sur- face, but on pedicle valve arranged in rows follow- ing costae. Ornament spines short and curved. Cos- tae discontinuous, generally confined to trail and lateral slopes. Brachial valve costate on anterior re- flected part and strongly spinose over entire surface, spines of ears and lateral margins larger and usually narrowly curved toward midvalve. Pedicle valve flattened umbonally, narrowly rounded at place of geniculation, trail long. Trail and geniculated region marked by moderately deep sulcus. Adductor field elongated, moderately thick- ened; diductor scars flabellate. Posterior margin with narrow ginglymus. Ears with striated baffle. Anterior slope with stout endospines. Brachial valve interior with prominent ears; adductor field thickened, consisting of two elon- gate inner scars usually thick and prominent, and two outer inconspicuous scars; breviseptum short. Lateral ridges poorly developed; brachial ridges often extravagantly thickened. Cardinal process with elongate and posterodorsally folded median lobe; shaft short and myophore rounded, lophidium small, carinate. Long endospines occupying in- terior near where trail deflects from visceral area. Type-Species.—Costispinifera costata (R. E. King, 1931:85, pi. 21:figs. 8-13) senior synonym of C. texana Muir-Wood and Cooper (1960:218, pi. 67: figs. 1-17). Diagnosis.—Partly costate and partly rugose Costispinifera with both valves strongly spinose. Comparison.—Costispinifera may be confused with several members of the same subfamily. Young of Echinauris may be mistaken for the young of Costispinifera, but specimens of the former are not strongly rugose, as are the young of Costispinifera. Adults of the two cannot be readily mistaken, be- cause Echinauris Muir-Wood and Cooper has much longer ear spines and it is not anteriorly costate. The nonspiny ears and generally stronger costation and less numerous spines serve to distiguish Liosotella Cooper from Costispinifera. In general appearance, Elliottella Stehli is almost exactly like Costispinifera but it does not have spines on the brachial valve. Other members of the subfamily are strikingly dif- ferent, and confusion of them with Costispinifera is unlikely. Discussion.—A few details of the genus should be discussed because some of them might be confus- ing to students unfamiliar with productids. The ex- terior of Costispinifera is its most distinctive char- acter and is quite complex; furthermore, like that of most other productids it is variable. The visceral region of old shells and the entire surface of youth- ful specimens having a length of 10 mm or less are strongly rugose. This feature is variable but where it is best developed it consists of narrowly rounded and fairly regular concentric rugae. These rugae are regular in their size but not in their course over the shell, because they are wavy where they pass around spine bases. In some specimens the rugae are regular and give an attractive pattern underlying the spines. In the majority of specimens, however, the pattern is obscured by irregularities in growth, accidents, or the wear to which a shell is subjected in the sea. Costae are not developed in conjunction with the rugae but appear just anterior to them and are entirely a feature of the anterior slopes, or trail. These are variable; most specimens have them fairly well developed, but in some their develop- ment was postponed until late stages of trail forma- tion. In some specimens, furthermore, they are nearly continuous but in others, they appear to be interrupted and discontinuous. In these they sug- gest elongate spine bases, because the trail spines are wholly confined to the costae. The brachial valve costae are generally confined to the genic- ulated or reflected part of the valve that forms the short trail. Although the spine arrangement is variable in detail, it follows a fairly definite pattern through- out the members of the genus. Spines of the pedicle valve are clearly divisible into two kinds: halteroid, or steadying, spines and ornament spines, which also probably play a minor role in steadying the 990 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY specimens on the sea bottom or anchoring in mud. The halteroid spines appear low on the lateral slopes and generally hang over the ears. Halteroid spines are few on the posterior margin and many specimens have none on the ears. Although a fair number of specimens have spines scattered on the ears, they are seldom numerous and usually not large. The longest halteroid spine measured is 20 mm and this was about equal to the length of the shell. These halteroid spines are not generally well preserved and no perfect specimens appear in the collection. The halteroid spines make a conspic- uous tuft on each side of the shell. They are readily distinguished from the ornament spines because they are fairly straight and extend laterally and posterolaterally, whereas the other spines are curved anteriorly. Most ornament spines appear to be short and taper distally. They are given off from a costa on the trail and are stouter at the base. They remain open but taper toward the free end. In some speci- mens the point of appearance of a spine is also the place of origin of a costa or part of one. Many spines are buttressed anteriorly by a costa that may extend to the margin or recede before reaching an- other spine base in line with it. In many specimens, however, many costae are continuous and the spines appear at a few or many points along the costa. The anteriormost spines, those that overhang the anterior margin, appear somewhat longer than those on the main part of the trail and thus may play a role in steadying the specimen if it lies on the bottom, and may have served a protective function as the shell gaped. Young specimens, and the older parts of the vis- ceral disc, have short spines curved and tapering that arise from inconspicuous, rounded bases. In- frequently, a short radial extension of the base may be noted, but this is usually interrupted by the con- centric rugae. The radial element does not become conspicuous until the shell starts to geniculate or change its general direction of growth. On the vis- ceral region no definite alignment of spines can be discerned, whereas on the trail, they are radial, but no lateral alignment is clear on this part. The ornament of the brachial valve has all the elements of the opposite valve, and, in addition, many scattered pits or dimples that appear to be complementary to some of the spine bases of the pedicle valve. The visceral region of this valve is usually strongly rugose, and the anterior genic- ulated, or deflected, part of the valve, which forms an anterior rim, is costate. The surface is covered by a veritable forest of fine spines of two sizes; those occupying the median parts are fine and hairlike, arising at an angle approaching 90° and usually curved toward the anterior; those on the posterior and anterior margins and on the ears are larger than those more medially placed, and commonly are abruptly curved medially. The spines on the ears and posterolateral slopes extend inward and lie over the umbo and the finer spines of the median region. Spines on the anterolateral and anterior borders may extend inward or outward with no apparent plan. The beak of the pedicle valve of Costispinifera is very small and the region around it is only slightly swollen. The beak hangs slightly over the delthy- rium, which is wide and indistinct. The ginglymus is a curved notch located in the adventitious shell just under the posterior margin on each side of the delthyrium. Laterally it extends to near where the ears become prominent. This narrow groove receives the posterior edge of the brachial valve which rotates in it. When more elaborately developed than in Costispinifera, it may be mistaken for an inter- area. It is especially well developed in the Dictyo- clostidae. The ear is a prominent feature of both valves of Costispinifera. In the pedicle valve it is less ex- tended but is narrowly rounded and concave, forming a small trough. The ear is demarcated from the visceral cavity by an oblique ridge or small shelf. The inner, or ventrad, margin of the ridge is marked by oblique striae and ridges that suggest that the hollow ear is a water channel for the feeding animal, as in Marginifera (Grant, 1968). These striae and ridges extend under the ears and along the inner valve wall to about midvalve in some specimens. Another feature of the interior of the pedicle valve is the scattered endospines, the purpose of which is not entirely clear. These may be as much as 1 mm long and may lie prone against the inner surface or may project at a high angle to the surface. The latter high-angle spines are usually short. Most endospines are hollow and are open at the free end. The spines are most numerous on the side walls under the ears and are rare or less numerous in the median part of the valve. These spines appear to be NUMBER 19 991 located in areas where incurrent streams are likely to be strongest. The exterior sulcus creates an interior median fold or ridge on which the adductor field is located. This ridge elevates the muscle scars, and when these are thickened they have the appearance of a long narrow platform. The scars are thickened only in the older shells, which appear to have an extremely long anterior pair and a much shorter posterior pair. Inside the brachial valve the ear, like that of the opposite valve, shows evidence of having shared in directing water currents into the mantle cavity. The brachial valve ear is somewhat narrowly rounded, more extended than that of the other valve, and is separated from the visceral area by an oblique groove. The side of this groove toward the anterior is marked by short, oblique ridges and grooves like the area just below the ear-ridge of the pedicle valve. This side of the groove has left a fairly distinct growth track in the form of a low ridge traceable to a point near the cardinal process. The cardinal process is short-shafted and in some specimens seems almost nonexistent. The myophore is swollen, rounded, and deeply grooved on its ventrad side. The groove in some is so deep as to be regarded as a pit. The median lobe of the myophore bearing the groove or pit is folded in a dorsal direction and tapers distally. It is usually fitted snugly between the two lateral lobes of the myo- phore, which are flattened laterally and, in some specimens, nearly meet behind the median fold. The cardinal process thus comes to have a trilobed appearance in posterodorsal view, the meeting lobe consisting of the folded part bearing the median groove and the lateral lobes bounding slits that must have been occupied by the muscle fibers. In old specimens, the myophore, except for the median folded part, is not visible when the shell is viewed from the interior. Near the base of the cardinal process the shell is thickened on each side by short ridges which form a broad V. Seen from the posterior these form a low platform on which the cardinal process rests. The beak of the brachial valve is deflected a short distance dorsally. The space between the posterior margin and the myophore is occupied by a narrow lophidium. At the base of the lophidium is an indistinct pit which receives the posterior angle of the delthyrium and helps to articulate the valves. The lophidium fits closely under the small beak of the pedicle valve and makes the union of the two valves snug. Lateral ridges are not developed to a noticeable extent in this genus. The adductor field of the brachial valve of Costispinifera is thickened into a definite adductor platform. Both adductor scars are elongate, but the inner scars are somewhat teardrop shaped. The outer scars wrap around the posterolateral margins of the inner scars and are thus long and slender in some specimens; in others they occupy the same postion but are fairly straight. The brachial ridge, as usual, originates between the inner and outer adductor scars, then extends directly laterally to the place where the anterior slope starts, makes a loop parallel to the edge of the slope, and then is narrowly looped to terminate at midvalve, well outside the outer edge of the adductor field. The line marking the origin of the anterior slope is occupied by long endospines which decrease in size posterolaterally and terminate near the groove separating the ears and the visceral region. Some endospines are 2.5 mm long. Growth.—The smallest specimen assignable to this genus measures about 2.5 mm in length and width. Up to about 5 mm the young have their length and width about equal. Specimens of this size and up to 10 mm, when well preserved, are usually provided with an attachment ring on the umbo of the pedicle valve. This may consist of one or more sets of spines curving up from the umbo to surround a small round object such as the spine of a parent or a small crinoid stem. Above 5 mm in length the growing shell begins to widen until it reaches maximum width, after which, it grows anteriorly without significantly widening. The lengthening of the trail is accomplished in a broad curve. Below 5 mm the brachial valve has no spines, no median septum, and the cardinal process is distinctly bilobed with the myophore in a primitive state. Between 5 and 10 mm this valve starts to develop spines, the median septum appears, and the median lobe of the cardinal process develops and is essentially adult before a length of 10 mm is reached. Stratigraphic Occurrence.—Costispinifera ap- pears to be confined to the Word Formation and its equivalents. In the Glass Mountains it appears in the China Tank Member but is very abundant in the lower part of the Willis Ranch Member. It is 992 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY the commonest productid at USNM 706, and there the preservation is superb. In the higher parts of the Willis Ranch Member it is extremely rare. It is also a rare shell in the Appel Ranch Member. In the Guadalupe Mountains it occurs in the Getaway Limestone Member of the Cherry Canyon Forma- tion, but is not common. In the Delaware Moun- tain Formation in the southern part of the Delaware Mountains, Girty (1909:269) reported a species of it as occurring in "considerable abun- dance." Costispinifera costata (R. E. King) Plate 320: figures 1-44, 45-51?; Plate 321: ficures 10-29 Avonia walcottiana R. E. King (not Girty), 1931:85, pi. 21: figs. 1-4. Avonia walcottiana costata R. E. King, 1931:85, pi. 21: figs. 8-13. Costispinifera texana Muir-Wood and Cooper, 1960:218, pi. 67: figs. 1-17. Medium size, hinge wide, ears prominent outline subquadrate; sides deeply indented anterior to ears but strongly rounded anteriorly; anterior margin broadly rounded and medially indented. Anterior commissure faintly uniplicate. Spines on both valves, numerous and slender. Costae variable, usually in excess of 20 and ranging to 26. Pedicle valve unevenly convex in lateral profile, anterior two-thirds, or trail, moderately convex but posterior third narrowly rounded, curvature great enough to bring surface of umbonal region approximately parallel to surface of trail at its maximum curvature. Anterior profile strongly domed, with precipitous sides and indented middle. Umbonal region projecting about one-third length posterior to hinge line, flattened, small pointed beak projecting slightly beyond hinge-fine. Umbo- nal slopes moderately steep; geniculated region greatly swollen. Trail and anterior slope long and rounded. Sulcus originating near place of genic- ulation or slightly anterior, shallow and broadly U-shaped, extending to anterior margin, here forming slight indentation. Flanks bounding sulcus rounded and with steep slopes. Ears triangular, convex, protruding beyond midwidth. Brachial valve deeply and evenly concave, maxi- mum cavity near midvalve; ears deflected ventrally, flattened to slightly concave, set off from rest of valve by low, oblique ridge; fold orginating near mid- valve, low and indistinct. Umbonal region forming shallow concavity. Pedicle valve interior with prominent ridge separating ears from visceral region; adductor field long and slender, moderately thickened in adults and old shells; endospines numerous, especially on lateral walls. Brachial valve interior with strong ear ridge, stout and somewhat bulbous cardinal process, small median septum, but long and stout endospines. Brachial ridge well developed only in old specimens. Measurements (in mm).— brachial surface hinge length valve length length width* midwidth height thickness USNM 706 124150a 21.9 21.9 13.8 45.0 22.3 14.0 7.5 149703a 16.3 12.9 32.5 19.6 18.8 10.8 6.6 149703b 14.5 11.6 23.0 15.1 16.0 9.7 6.6 149703c 12.0 10.9 18.5 8.6 14.0 4.8 2.7 149703d 20.7 14.7 35.0 27.6 22.7 12.5 6.8 149703g 17.0 12.6 34.5 19.4? 19.0 11.7 7.7 149703J 13.3 12.1 25.0 14.4 15.7 8.2 4.5 1497031 12.7 11.1 22.0 13.6 14.8 7.0 4.0 149703p 19.0 12.0 38.0 20.0 20.6 12.0 6.6 149703W 10.8 9.6 16.5 7.7 12.3 5.2 3.5 149703X 9.0 8.4 12.0 6.2 10.5 3.4 1.6 149704a 6.3 5.8 8.0 6.1 7.8 2.2 1.2 149704b 5.5 4.8 6.0 3.9 5.4 1.6 1.1 149704c 4.8 4.4 5.0 3.4 4.7 1.5 1.2 #Ears on all specimens < lamaged; hinge width approximate. NUMBER 19 993 Stratigraphic Occurrence.—Word Formation (Willis Ranch Member and lens between Willis Ranch and Appel Ranch members). Localities.—Willis Ranch: AMNH 506; USNM 704, 706, 706e, 718d, 723w, 724u, 731 u. R. E. King T240, 241. Lens: USNM 706b. Diagnosis.—Costispinifera with numerous fine costae. Types.—Lectotype: T 10282a. Figured paratypes: T10282b-f, YPM 11568. Figured hypotypes: USNM 124150a, b; 124151b, c; 149702a-e; 149703a, b, d, i, o; 153864a, c-g; 153871a-c; 153872a-f. Measured hypo- types: USNM 124150a, 149703a-d, g, j, 1, p, w, x; 149704a-c. Unfigured hypotypes: USNM 124151a; 149703c, e-h, j-n; 153864. Figured specimens: USNM 153865, 153866, 153867. Comparison.—Differs from C. rugatula (Girty) by its finer costation, finer spines, and larger, more extended, ears. Discussion.—This is a very abundant species in the lower part of the Willis Ranch Member. Much of the information in the discussion of the anatomy under the genus was derived from this species. King's cotypes are from the Willis Ranch Member in the hill north of Leonard Mountain. Although all of his specimens are greatly decorticated, it is necessary to select a type specimen from them. We choose specimen Tl0282a (R. E. King 1931, pi. 21: figs. 10a,b) to be the type of the species because it best preserves the shape, beak, both profiles, and a suggestion of the ears. Restudy of King's and Girty's specimens makes it necessary to put into synonymy C. texana Muir- Wood and Cooper. Comparison of silicified and decorticated specimens often leads to many diffi- culties of recognition. Costispinifera rugatula (Girty) Plate 310: figures 62-70; Plate 312: figures 21-24; Plate 319: figures 1-56; Plate 321: figures 1-9 Productus subhorridus var. rugatulus Girty, 1909:267, pi. 30: figs. 1I-12C—R. E. King, 1931:84, pi. 20: figs. 12, 13, 15. Costispinifera having essentially same outline and profiles as C. cosíala but differing in several anatomical features and details of ornament. Umbonal and visceral regions of both valves marked by narrow, elevated concentric lines to place of geniculation; there concentric ornament displaced by strong, irregular costellae, variable in develop- ment, some specimens having continuous costellae but in others these appearing on anterior side of spine, and interrupted. Ornament spines moderately long and curved, stout; halteroid spines long and stout. Brachial valve strongly marked concentrically in visceral region and deeply pitted. Pits crudely arranged radially and anteriorly occupying spaces between costae. Pedicle valve with moderately deep sulcus extending from place of geniculation to slightly indented anterior margin. Ears moderately devel- oped. Brachial valve deeply concave, maximum concavity near midvalve; umbo forming deeply concave pit. Brachial valve interior with thick adductor plat- form and stout endospines. Measurements (in mm).—Costisp inifera rugatula, new species: brachial surface hinge length valve length length width midwidth height thickness USNM 706c 149715a 22.7 15.0 ? 23.2 20.9 13.0 8.8 149715b 17.7 14.4 34.0 18.0? 20.0 12.2 7.1 149715c 18.2 14.3 37.0 19.9 20.6 13.0 8.4 149715d 15.6 12.4 30.5 18.3 17.8 10.9 7.0 149715e 14.1 11.0 28.5 18.6 16.8 9.5 6.0 149715f 13.6 11.1 26.0 14.3 15.5 9.1 5.1 149715g 12.6 11.3 19.5 10.4 14.6 6.2 3.7 149715h 9.7 8.7 16.0 7.5 10.8 4.4 2.4 149715Í 8.8 7.9 12.5 7.6 10.0 3.1 1.4 149715J 6.1 5.5 7.5 4.5 7.0 1.9 1.0 149715k 4.5 4.2? 5.5 3.3? 4.8 1.7 0.7 994 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Stratigraphic Occurrence.—Road Canyon For- mation, Word Formation (China Tank Member, and lens between Willis Ranch and Appel Ranch members). Localities.—Road Canyon: USNM 706f, 713, 716xa, 721j, 724b, 732j. China Tank: USNM 706c, 726r, 731m, 732s, 733q. Lens: USNM 706b. Diagnosis.—Like Costispinifera costata (R E. King) but with stronger costation, more discon- tinuous costae, stouter spines, and larger pits in the brachial valve. Types.—Holotype: USNM 118536a. Figured paratype: USNM 118536b. Figured hypotypes: USNM 149708a-e; 149715 a, c, e-j; 153862a-c; 153863 a-d, f; 153868d, g; 153869; 153870a, b; 153878a, b; 153905. Measured hypotypes: USNM 149715a-k. Comparison.—This species has a slight overlap with C. costata because the more numerously costate members strongly suggest some of the more coarsely costate members of that species. Generally, however, it is usually easy to distinguish the two species even though their size and shape are almost identical. Costispinifera rugatula is more strongly ribbed than C. costata in all stages of growth and, furthermore, its spines are much stouter than those of the younger species. Another point of distinction is the smaller and less extended ears of C. rugatula. They are pointed but are seldom extended laterally like those of C. costata. Girty's type lot consists of two specimens, one complete with brachial valve but the other a single pedicle valve. Unfortunately, both specimens are young forms having the pronounced concentric wrinkles that characterize the young stages of this genus. They are also more sparsely costate anteriorly and have more scattered spines than many of the adult specimens. Costispinifera walcottiana (Girty) Productus walcottianus Girty, 1909:269, pi. 21: figs. 27, a, b [not 28]. [Not Avonia walcottiana King, 1931:85.] Small, wider than long, outline subquadrate; sides rounded; anterior margin indented; lateral profile strongly convex, gently convex visceral region and long moderately convex trail. Beak small; umbo narrowly convex, steep slopes to ears. Place of geniculation narrowly rounded. Sulcus fairly deep and moderately wide, originating near middle of visceral area. Flanks bounding sulcus narrowly rounded and with steep lateral slopes. Visceral region marked by strong, wavy concentric rugae and scattered, rounded spine bases. Trail marked by interrupted costae, strongest on anterior side of spine bases. Costae ending abruptly near midpoint of rounded geniculated area. Ears not preserved. Spines, as indicated by bases, fairly stout. Measurements (in mm).—Holotype: length 12.1, surface length 25.0?, hinge width 13.0?, mid- width 17.1, height 10.0. Stratigraphic Occurrence.—Delaware Moun- tain Formation (700 feet above the basal black limestone) according to Girty (1909) but assigned to the Getaway Limestone Member, Cherry Canyon Formation, by Newell, et al. (1953). Locality.—USGS 2903 (green). Diagnosis.—Compressed Costispinifera with width considerably greater than length, strongly costate trail and strongly wrinkled visceral region. Types.—Holotype: USNM 118537. Comparison.—This species differs from Costi- spinifera costata (King) in its greater proportional width, less numerous costae, and compressed pro- file. Discussion.—Girty based this species on two spec- imens, one, the holotype, from the Delaware Moun- tain Formation (Getaway Limestone Member of the Cherry Canyon Formation) and the other, USNM 118538, on a filling of the interior of the pedicle valve, found on the side of the road opposite from USGS 2903 in Gualalupe Canyon. It is impossible to be sure that the two are the same. King (1931: 85) believed with Tschernyschew (1916) that they are not the same and placed the internal mold in the subspecies A. walcottiana cos- tata. It is doubtful that this specimen should be assigned there, consequently at the present time it fits in none of the accepted categories. It is also impossible to identify the abundant and well- preserved Glass Mountain species with Girty's specimen. A suite of specimens is greatly needed to establish the true specific characters of C. walcot- tiana. Genus Elliottella Stehli, 1955 Psilonotus Stehli, 1954:323. [Not of Walker, 1834, insect.] Elliottella Stehli, 1955:711. Usually small, transversely rectangular, squarish NUMBER 19 995 to subcircular outline; hinge usually equal to or greater than midwidth; ears commonly large and conspicuous; anterior commissure usually with narrow fold in dorsal direction (uniplicate). Pedicle valve strongly convex; brachial valve deeply con- cave, with thin visceral chamber. Pedicle valve exterior with fairly strong concentric wrinkles in visceral disc region; venter and trail strongly but irregularly costate; halteroid and ornament spines scarcely differentiated, given off from costae; orna- ment spines long and curved anterodorsally; halteroid spines directed anterolaterally and pos- teriorly, those on lateral slopes arranged in crudely curved rows. Brachial valve concentrically rugose in visceral and posterolateral regions, trail costate and with dimples corresponding to spines of pedicle valve on visceral disc and slopes; no spines on brachial valve. Pedicle valve interior with elongate adductor scars located on internal ridge produced by external median sulcus; ear baffles strong, striated, commonly continued as ridge inside lateral margins in old shells; interior spine bases on lateral slopes. Brachial valve interior with small, sessile, margin- iferid cardinal process; myophore small; lophid- ium small; lateral ridges joining striated ear baffles. Adductor field elongate, scars teardrop-shaped; breviseptum delicate; endospines small, on narrowly rounded geniculated area. Brachial ridges as usual for Costispiniferidae. Type-Species (by original designation).— Psilonotus transversalis Stehli (1954:323). Diagnosis.—Anteriorly costate Costispiniferidae irregularly spinose, without spines on brachial valve, and with small lophidium. Comparisons.—Elliottella suggests Costispinifera at first glance but exterior features of the two gen- era, such as the costation and spines of the pedicle valve, are really quite different. The costae of Elliot- tella are strong and continuous, while those of Cos- spinifera are usually narrow and interrupted, and are usually shorter than those of Elliottella. Another important difference between the two genera is the abundance of spines on the brachial valve of Costispinifera and their absence from that valve of Elliottella. Desmoinesia Hoare might be confused with Elliottella, but it has a spinose brachial valve and the costellae of both valves are more regular and finer than those of Elliottella. Interior differences between Desmoinesia and Elliottella are the pres- ence of a thickened rim on the margin of the pedicle valve of Desmoinesia and its absence in Elliottella, the strongly endospinose interior in the midregion of Desmoinesia, and the absence of a lophidium in the same genus. Elliottella differs from Echinauris Muir-Wood and Cooper in not having spines on its brachial valve and in having a strongly costate trail. Hystriculina Muir-Wood and Cooper and Elliot- tella strongly resemble one another but the former has only a few scattered spines, fairly regular and weak radial ornament, and a feebly developed marginal ridge, the last a feature not usually present in Elliottella. Discussion.—Because of the nondescript nature of the spines and the general similarity to other anteriorly costate genera having small shells, Elliottella is not an easy genus to recognize, and recognition becomes even more difficult in poorly preserved or nonsilicified material. No definite pattern or plan has been discerned in the arrangement of the spines. The anterior orna- ment spines appear to have been as long as the halteroid spines, but they are strongly curved antero- dorsally and at the front margin they hang over the dorsal valve. Small halteroid spines appear on the posterior margin and occasional ones on the ears. The costae on the trail are generally strong and elevated, with fairly deep grooves between. A few of them appear to originate with a spine, but most of them are present on the venter and bear several spines. The ears of both valves are prominent. On the pedicle valve they are moderately rounded in section and moderately concave on the interior. Those of the brachial valve are moderately rounded inter- nally but somewhat flattened on the exterior. Baffles across the ears are fairly well developed in both valves. In old pedicle valves the striated baffle is continued laterally along the inside of the lateral margin, but it usually dies out near midvalve or slightly beyond. The same is true of the brachial valve. A ridge extends laterally from the base of the cardinal process, then extends obliquely to join the ear baffle. In some of the older specimens it is extended for a short distance beyond midvalve, where it dies out. Inside the pedicle valve few features can be determined with certainty in the type species. The 996 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY adductor field is seldom thickened to a notable degree. The lateral slopes just ventrad of the ear baffle generally are marked by a row of elongate slits, or holes, with thickened rim. These represent the points of entry of the spines forming the outer- most row on the outside of the lateral slopes. Each hole generally can be linked to a spine on the exterior. The slitlike form of some of them may indicate that they are being gradually closed by the mantle. The cardinal process of Elliottella is typically marginiferid and shows no exceptional features. It is generally nearly sessile, but most specimens build up at its base a thickening or platform that may protrude slightly beyond the posterior margin. The inner adductor pair is generally easily visible and is commonly thickened to some extent but rarely considerably thickened. The region between the posterior end of the adductors and the anterior end of the cardinal process is somewhat thickened generally, but exceptionally becomes rounded and ridgelike, uniting with the thickened breviseptum. The latter is generally thin and delicate and is commonly so badly worn as to be visible only with difficulty. When well preserved, it is bladelike and has a steep anterior edge. Brachial ridges are usually present but are commonly obscure and incomplete. When well preserved, the outside margins of the loops overlap on the inner rim of endospines. The region occupied by the endospines is very convex and fits snugly into the inner part of the venter of the pedicle valve. The endospines are moderately large and form a narrow patch where the visceral disc passes into the anterior slope or trail. Growth.—Elliottella is another of the genera that attached by rings of spines at the umbo in its youthful stages. The most youthful forms are nearly circular in outline, with one or two rings, usually with strongly rugose valves and a few spines of considerable length, commonly longer than the valve length. A specimen about 3 mm in diameter has 5 spines on each side of the midline. Another 4 mm long by 4.5 mm wide has 8 spines on the body and 2 on the posterior margin on each side of the umbo. At an early age, before attaining 3 mm in length, the shells are generally definitely wider than long. They are flatly convex. The development of strong convexity is a variable feature. Elliottella minima (Stehli) Plate 323: figures 1-24 Psilonotus minimus Stehli, 1954:324, pi. 22: figs. 17-19. This species is generally smaller than the other two in the Sierra Diablo and is characterized by stronger, more crowded costae; the majority of the specimens maintain this strong costation, especially in adulthood. Measurements are given below for comparison with those of Elliottella multicostata, new species, and E. transversalis (Stehli). Stratigraphic Occurrence.—Bone Spring For- mation, Skinner Ranch Formation. Localities.—Bone Spring, AMNH 625, 631; USNM 728e, 728f, 745. Skinner Ranch: AMNH 520. Types.—Stehli designated two syntypes and a number of paratypes. The syntypes were, undoubt- edly, his leading specimens. Consequently we select Measurements (in mm).—Elliott* ella minima (Stehli): brachial surface hinge length valve length length width midwidth height thickness USNM 728e 152707a 12.7 10.3 25.0 14.2 15.3 8.8 5.0 152707b 12.3 10.2 23.0 16.0 14.4 8.4 3.4 152707c 11.9 9.4 21.5 13.0 13.4 7.5 4.6 152707d 11.6 9.4 20.5 15.0 15.0 8.0? 2.8 152707e 10.5 8.8 19.5 12.3 13.2 6.5 3.2 152707f 10.4 8.5 17.5 13.5 14.1 5.7 1.8 152707g 10.4 8.7 16.0 11.4 13.7 5.5 3.0 152707h 9.4 7.9 16.0 10.0 12.1 5.5 2.1 1527071 8.5 6.7 14.0 8.4 10.5 4.8? 2.1 NUMBER 19 997 one of these, the pedicle valve AMNH 27306/1:1, as lectotype. The other syntype AMNH 27306/1:2 becomes the paratype. Figured hypotypes: USNM 152707 b,d,j-n. Measured hypotypes: USNM 152707 a-i. Unfigured hypotypes: USNM 152707 a,c,e-h. Discussion.—Our measurements and Stehli's figures indicate a transverse species but the descrip- tion states that E. minima differs from E. iransver- salis "in being much longer in proportion to its width". Our measurements give an average length- width ratio of 0.79 which indicates a transverse shell. This figure is based on the midwith. Using the hinge width, the ratio is 0.87, a less wide shell in proportion to its length but nevertheless transverse. Elliottella multicostata, new species Plate 323: figures 25-58 Large for genus, transversely rectangular in out- line, hinge generally wider than midwidth; cardinal extremities variable from slightly obtuse to extended and rounded ears. Sides gently rounded; anterior margin broadly rounded and usually gently emar- ginate. Surface multicostate, costae numerous, numbering about 26, with 2 to 6 in sulcus and 9 to 10 per 10 mm at margin; costae bounding sulcus often convergent; halteroid spines numerous: forming rows on costae and in row along posterior margin; spines at base of umbonal slope long and straight; costal spines bent anteriorly, becoming parallel to trail surface. Umbonal region crudely reticulated, with spines extending from nodes. Brachial valve with strong regular concentic undulations lateral to umbonal pit; costae subdued and only slightly elevated. Pedicle valve strongly but unevenly convex in lateral profile, maximum convexity posterior to midvalve; anterior profile forming broad dome, indented medially by sulcus and having strongly sloping sides. Umbonal region moderately inflated; median region strongly convex; sulcus originating on posterior side of venter, narrow, variable in depth but generally moderately deep; flanks bounding sulcus moderately swollen; anterior slope long, convex, and fairly steep. Ears deflected and slightly convex. Brachial valve geniculated near midvalve; deeply concave, greatest depth near midvalve; lateral and anterior slopes steep; median fold low, incon- spicuous, originating just posterior to midvalve; umbonal pit moderately deep. Ears deflected, slightly concave. Pedicle valve interior with adductor field only slightly thickened; myophragm elevated but short and low. Brachial valve interior with small sessile, margin- iferid cardinal process; lateral ridges moderately developed and forming fairly strong, striated ear baffles not extended anteriorly as ridges; adductor scars slightly thickened; breviseptum low; endo- spines fairly numerous, small but stout. Measurements (in mm).— brach- ial sur- valve face hinge mid- length length length width width heig. USNM 728h 151590a 16.0 13.5 27.0 18.2 20.7 9.8 151590b 15.2 13.3 26.0 20.5? 20.7 8.9 151590c 13.8 11.4 25.0? 18.0 19.6 8.4 151590d 13.5 11.5 24.5? 18.0 18.8 8.3 151590e 13.8 11.4 24.5 18.0 19.7 8.0 151590f 13.7 11.2 23.5 14.6? 18.0 7.8 151590g 13.6 11.0 26.0? 17.5 16.8 8.6 151590h 12.3 10.0 21.5 17.0 18.5 7.6 151590Í 11.0 9.4 17.0 13.5 14.6 5.9 151590J 12.4 9.6 22.0 15.0 15.9 8.8 151590k ? 10.0 13.5 13.0 15.5 5.0 1515901 ? 11.6 15.5 14.5 17.5 5.3 151590m ? 11.0 15.5 15.0 18.0 5.9 151590n ? 10.8 17.0 17.0 18.2 5.7 151590o ? 10.6 15.0 14.7 16.7 5.4 153882d 14.5 ? 25.0 18.8 18.6 8.0 (holotype) Stratigraphic Occurrence.—Bone Spring For- mation (lower). Localities.—USNM 728e, 728h, 746. Diagnosis.—Elliottella with numerous costae and spines. Types.—Holotype: USNM 153882d. Figured paratypes: USNM 151589a; 153882a-c, e-k. Mea- sured paratypes: USNM 151590a-o. Comparison.—The closest species to Elliottella multicostata is E. transversalis (Stehli). The two differ markedly in the number and strength of the costae, E. multicostata having more numerous cos- tae in both valves. The disparity between the costae is especially marked in the brachial valves; that of E. multicostata has many more costae, but they are greatly subdued and in some specimens are obscure. The sulcus of E. multicostata is generally less 998 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY strongly developed than that of E. transversalis. Spines are generally more numerous on the former species than on E. transversalis. Discussion.—Several fine immature specimens show well the development from an umbonally ringed stage to the adult. Most of the young appear to have been attached to productid spines, because the apex generally has a narrow and round groove. The small size of most of the attachment rinçs with the grooved umbo support this view. The smallest specimens are about 2 mm in diameter, with the earliest umbonal spines numbering four, one on each side and two in the middle. Others have only one in the middle. There seems to be no uniformity in the development of these structures. A specimen of 4-mm diameter has a large attachment scar and a large ring composed of two spines. A row of small spines appears along the margins of the attachment scar. Small attachment spines in additon to the ring spines may appear on the umbo. Evidently the young Elliottella could put out spines where they were needed. Elliottella transversalis (Stehli) Plate 322: figures 1^43 Marginifera? whitei King (part), 1931:90, pi. 23: figs. 2a-c, 3a, b. Psilonotus transversalis Stehli, 1954:324, figs. 12-16. Elliottella transversalis (Stehli), 1955:711. This abundant species in the Sierra Diablo was described fully by Stehli (1954) and needs no formal description here. The abundance of speci- mens in the collection, however, permits the addi- tion of facts about the species not recorded in the original description. The species is extremely variable, as are most productids; consequently, the costae of the exterior are not uniform, nor is the development of the fold and sulcus or the complement of spines. The costae vary from coarse, strong, and crowded to irregular, scattered, and with wide spaces between them. In some specimens the costae on the trail are very regular and fairly even in size, but in a few speci- mens the costae become very numerous, in others sparsely scattered. The sulcus varies from non- existent to deep and indenting the anterior margin. The specimen described by King as Marginifera? whitei is an individual with coarse costae and no sulcus. This is not a common aberration but the U. S. National Museum of Natural History collec- tion contains specimens like his. The spines are variable in length and form. The trail spines of a few specimens are strongly curved coming off the costae at an angle of about 90° but bending strongly to a position parallel with the surface of the trail. In other specimens the spines extend out directly with only slight curvature when they may attain a length of 18 mm. The ear and umbonal slope spines in some specimens attain the same length. The grooved condition of the umbo of some spat indicates that the young of this species were attached to productid spines or other round objects in their early stages. Many of these spat have the character- istic ring of one or two spines which seems to be a usual feature of the productid young. These spat also have a few ornament spines that are enormously long for such small shells. Unlike the Glass Mountains specimens of this genus, those from the Sierra Diablo do not exhibit anteriorly elevated adductor scars inside the brachial valve. The brachial ridges of this species are not well developed. Stratigraphic Occurrence.—Bone Spring For- mation (lower). Localities.—AMNH 628, 629, 696; USNM 728e, 728f, 728h, 742. Types.—Figured hypotypes: USNM 153883a-h, i-p- Elliottella varicostata, new species Plate 325: ficures 25-60; Plate 446: figures 11-17 About medium size for genus, transversely sub- rectangular outline, hinge equal to or slightly greater than midwidth. Sides gently curved; anterior broadly rounded and slightly indented medially. Ears fairly large, bluntly pointed. Surface costate and spinose. Costae strong, rounded, crowded, ranging from 4 to 6 per 5 mm on flanks, 2 to 4 in sulcus: in many specimens sulcus convergent anteriorly and pinching out earlier formed costae. Spines all of halteroid type, erect, and consisting of row along posterior margin including one on ear, curved row at base of lateral slope, and scattered NUMBER 19 999 spines on visceral disc and trail, apparently without definite arrangement. Pedicle valve fairly strongly convex in lateral profile, posterior third having greater convexity but umbonal region flattened; anterior profile strongly domed, medially indented, lateral slopes steep. Beak small, umbo flattened; posteromedian region inflated; sulcus originating on venter, nar- row but nearly parallel-sided and fairly deep throughout length. Flanks rounded and steep sided. Brachial valve conforming closely to pedicle valve, thus forming shallow visceral chamber; valve deepest medially, moderately steep sides and ante- rior; umbo depressed; fold low, carínate, originat- ing slightly posterior to midvalve, indenting margin slightly. Ears demarcated by oblique ridge, moderately concave. Pedicle valve interior with smooth, tear-shaped adductor scars, moderately elevated; ear baffles strong, with inner surface strongly striated, and continued anteriorly as low ridge, not, however, extending around anterior margin. Brachial valve interior with small sessile cardinal process, moderate buttress thickening anteriorly; adductor platform moderately elevated, inner pair of scars divisible into two scars, outer pair small and inconspicuous. Ear baffles low, striated on outer face and extended anteriorly along inside of lateral margin as low ridge. Brachial ridges thick and strongly elevated on anterior side of loop; brevi- septum strongly elevated and distally free. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 705a 152706a 13.2 9.9? 25.0 18.6 16.9 8.3 ? 152706b 13.2 10.2 25.0 17.8 16.5 8.3 ? 152706c 13.8 11.0 25.0 17.3 17.0 8.1 ? 152706d 12.6 9.6 23.0 15.8 14.6 7.9 3.4 152706e 13.3 9.8 24.0 15.8? 14.5 8.4 3.5 152706Í 12.2 10.6 22.0 18.5 16.4 7.6 3.3 152706g 11.0 9.2 18.5 14.6 13.6 6.2 2.5 152706h 11.6 9.3 18.0 13.0? 13.9 5.8 2.4 152706Í 11.0 9.2? 17.0 13.3 13.9 5.2 ? 152706J 12.6 10.0 22.0 15.2 15.2 7.3 ? 152706k 11.4 7.5 18.5 14.0? 12.3 6.5 2.6 1527061 9.9 8.0 16.0 12.0? 11.7 5.0 2.3 152706m 10.1 8.7 15.5 11.6 12.5 5.2 1.7 152706n 12.8 11.0 20.0 17.3 16.0 7.0 2.9 (holotype) Stratigraphic Occurrence.—Skinner Ranch Formation (lower), Cibolo Formation. Localities.—Skinner Ranch: USNM 705a, 705n, 709v, 71 lp, 714e, 715v, 716p, 720e, 720g, 724p, 726h. Cibolo: 728-1, 738r. Diagnosis.—Compact, medium-sized Elliottella with variable costae. Types.—Holotype: USNM 152706n. Figured paratypes: USNM 152706a, c, e, o, q-s; 153881a, b. Measured paratypes: USNM 152706a-m. Unfigured paratypes: USNM 152706b, d, f-n, p. Figured speci- men: USNM 153910a. Comparisons.—Compared to Elliottella transver- salis (Stehli) from the Sierra Diablo, the Glass Mountains species is smaller and less transverse and has more costae in the sulcus. Elliottella varicostata differs from E. minima (Stehli) in the variability of its costation, the deeper, subparallel-sided sulcus, and the development of a pronounced fold in the brachial valve. Discussion.—The striking feature of this species is the variation of its ornament. Although some natural variation exists in the outline and profiles as it does in all productids, these features seem relatively stable compared to the ornament. A few specimens have strong, closely crowded, rounded costae with the sulcus occupied posteriorly by 2 costae, but these median costae are pinched out 1000 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY anteriorly by 2 large costae. In other specimens the sulcus is occupied by 4 or more costae from its place of origin to the front margin. The flanks of one specimen are occupied by 6 costae, but those of another have 10 or more. Bifurcation of costae is also common, and helps contribute to the variation. Another variation is that a spine base located on a broad costa may induce the formation of a super- imposed rib on the costa. All degrees of change exist between the extremes of costation. Genus Echinauris Muir-Wood and Cooper, 1960 Echinauris Muir-Wood and Cooper, 1960:221.—Williams et al., 1965:H480.—Grant, 1968:26.—Stchli and Grant, 1970:31. Small, subcircular to subquadrate outline; concavo-convex, with short visceral region, long trail and well-rounded area of geniculation. Ears generally small, acute. Anterior commissure with faint dorsad fold. Pedicle valve obscurely to moderately strongly sulcate. Surface provided with halteroid and ornament spines; former confined to lateral slopes, long and extending laterally or irregularly at high angle to shell surface; ornament spines short, curved anteriorly and extending at high angle. Brachial valve spines consisting of large marginal spines generally curving medially, and thinner spines scattered over concave surface at high angle. Other ornament on brachial valve consisting of shallow, scattered dimples. Pedicle valve interior with narrow and elongate adductor platform separating flabellate diductor scars; ears with narrow, interiorly striated baffle; subperipheral rim extending from ears to antero- lateral extremities. Endospines in lateral walls. Brachial valve interior having bilobed adductor platform with interior scars tear-shaped and promi- nent but outer pair dendritic and obscure. Cardi- nal process stout, short shafted and with rounded myophore; lophidium small; brachial ridges poorly developed; ears bounded by striated, curved ridge; endospines numerous, in several rows, larger being posteriormost and descreasing in size anteriorly. Type-Species.—Echinauris lateralis Muir-Wood and Cooper, (1960:222, pi. 68: figs. 1-13). Diagnosis.—Costispiniferidae ornamented by spines and spine ridges on pedicle valve and spines and dimples on brachial valve, lateral halteroid spines long and extended laterally. Comparisons.—Although Echinauris, when well preserved, is a very distinctive brachiopod, it is, nevertheless, difficult to separate from several genera when the spines have been stripped away or in old specimens which have a tendency to exaggerate minor features. Compared with other members of the family, Echinauris is most like Costispinifera Muir-Wood and Cooper, Ellioltella Stehli, and Liosolella Cooper. Costispinifera differs from Echinauris in having more elaborate ornamentation and different hal- teroid spine arrangement. The anterior slopes of Costispinifera are usually strongly costate, the costae often interrupted by spine bases, but in Echinauris these slopes are generally without costation although in some species elongate spine bases give the appear- ance of costation. The visceral region of Costispin- ifera is usually strongly concentrically wrinkled in both valves but this is not true in Echinauris. Another distinction between these genera appears in the halteroid spines. In both genera these are mainly confined to, or most prominent on, the lateral slopes, but those of Echinauris are longer, thicker, and extend more directly laterally or are irregular in direction. The halteroid spines of Costispinifera are frequently not much larger in diameter than the ornament spines and they generally are extended strongly posterolaterally rather than laterally as in Echinauris. Elliottella is easily distinguished from Echinauris because it is strongly costate, has no zone of con- centrated halteroid spines, has a concentrically wrinkled visceral disc, and has no spines on the brachial valve. Distinction between Echinauris and Liosotella in well-preserved specimens is easy. Internally, their cardinal processes differ. Moreover, Liosotella has prominent, spineless ears with a single row of strong halteroid spines on the lateral slopes and a strongly costate anterior slope. In worn specimens stripped of their spines, however, the distinction is not always simple. Discussion.—The exterior surfaces of Echinauris between the spines and their bases might be de- scribed as smooth. No prominent concentric lines are present on any of the species and no prominent radial ornament is present. Specimens vary in the development of secondary radial markings. Most juveniles and young adults do not have radial ridges, but many old specimens have interrupted ridges extending longitudinally anterior to the bases of the spines. These then suggest Costispinifera, but the ridges are seldom as well developed as in that NUMBER 19 1001 genus. The brachial valves are essentially without radial ridges of any sort and give a good clue to the generic affinities when the pedicle valve is moder- ately ridged. The most conspicuous feature of well-preserved Echinauris is the halteroid spines. Length of the longest spine seen in the type species is 40 mm (slightly over 1.5 inches). The spines extend directly laterally in only a few specimens, most of them extending ventrolaterally or even less frequently posterolaterally. These spines spring mainly from the lateral slopes, from the ears to the anterior margin. The spines are thus bunched and form a sparse tuft overhanging the ears when viewed from the ventral side. The ornament spines are much shorter than the halteroid spines and are usually fairly strongly curved anterodorsally. The longest spine seen is slightly less than 20 mm long in the type species. At the anterior these spines curve over the margin and over the anterior gape to some extent. A crude lateral alignment can be detected in many of the specimens. The spines appear mainly at the front margin; consequently, a row of them may appear while the shell is resting from its forward growth. When growth resumes, the margin grows away from the latest formed spines, leaving them in an irregu- lar row near the margin. The spine arrangement of the brachial valve appears to have less of a pattern than that of the pedicle valve. The posterior spines and those on the margins are much stouter than those covering the more median parts of the shell. These spines curve abruptly and extend toward midvalve, those from each side tangling at midvalve and forming a mat over the concave valve. The more slender spines in the median parts are given off at a high angle and may protrude beyond the shell margins. In some species they extend for a considerable distance in a dorsal direction. A specimen (USNM 152715) of E. lappacea, new species, from USNM 707e shows the spines on the anterior margin curving toward midvalve and tangling with those from the sides to form a mat over the concave valve surface. A possible explanation for the spines of the brachial valve is that they fulfilled a protective role. Although many productids, such as Elliottella, are very similar to Echinauris, they are not provided with such spines. Furthermore, the possibly pro- tective nature of these spines may be very dubious because many brachial valves in the collection are heavily encrusted by other brachiopods and bryo- zoans. In some the spines serve as the substrate, but in others the intruder established itself directly on the valve surface under the mat of spines. No ginglymus was seen along the hinge of Echinauris. The ventral surface on each side of the beak forms a ridge that apparently fits into a slot on the brachial valve that lies parallel to the posterior margin and just inside of it. The margins of the valve just under the beak are thickened where they fit on each side of the cardinal process to form a crude kind of articulation. The ears are variable but generally flattened in younger shells to form a small shelf, the inner slope of which is marked by oblique striae. In older shells the shelf becomes so thickened that it forms a narrow fold across the ear, and an inner thickening extends from the ear for half the distance to the anterior margin. The adductor field is long and slender, generally not greatly thickened. The anterior pair of adduc- tors is long and slender, lying inside the posterior pair which are less clearly defined but are also long and slender. The anterior and lateral internal slopes of many specimens are adorned by scattered short endo- spines, the purpose of which is not entirely clear. In some these spines are tapered and closed at the free end, but, in others, they are open and hollow. Some appear to connect with spines on the exte- rior. Although the interior of the brachial valve is similar to that of Costispinifera, small differences are consistent and significant. The cardinal process is short shafted and has a somewhat bulbous myo- phore. The ventral face is grooved, and the median lobe of the process is narrow and extends posteri- orly for some distance. It is bounded by the nar- rower lateral lobes, leaving a narrow slit between them. The process in adults rests on a fairly thick- ened platform that protrudes posterior to the poste- rior margin. On the ventral side, the process and the lateral ridges are welded together and stiffened axially by a swollen ridge extending anteriorly to the adductor platform. The latter is present usu- ally only in old adults. The lateral ridges are short and are not extended parallel to the posterior mar- gin but extend anterolaterally in the same line as the ear baffles. On the dorsal side of the cardinal process the lophidium is short, narrow, and carí- nate, just a small ridge on the cardinal process platform. 1002 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY The ears are narrowly rounded when seen from the inside and are divided from the visceral area by a narrow, oblique groove. The inside margin of the groove is steep and is striated along the groove and slightly anteriorly beyond it. The adductor platform consists of two triangular patches on each side of the breviseptum. The patches consist of a strongly thickened median pair of marks and less thickened, less clear patches out- side of them. Each scar of the median pair is some- what tear-shaped and more prominent than the outer pair. The inner scars appear themselves to be divisible indistinctly into two patches, an inner long and slender one, and an outer narrow and short one. In most specimens, the outer indistinct pair of scars is usually dendritic and without clear definition. The breviseptum, when clearly visible, extends from a point between the adductor scars to just beyond midvalve. In many specimens the longi- tudinal thickening of the cardinal process shaft and lateral ridges extends anterior to the posterior edge of the adductor scars and thus becomes con- tinuous with the breviseptum. In such cases the cardinal process shaft and breviseptum appear to be one structure. The differences between the two are not difficult to detect on close examination. In large and old specimens the breviseptum extends anterior to its anteriormost point of junction with the valve floor as a short projection with a sharp anterodorsad point. A major difference between Costispinifera and Echinauris is the dense cover of endospines on the anterior slope of the latter as compared with the single row of large endospines in Costispinifera. The endospines of Echinauris appear in several genera- tions, decreasing in size from the origin of the anterior slope anteriorly. The row of largest spines extends from the slope overhanging the ear groove, around the anterior, parallel to the line of slope, changing from visceral area to anterior slope. Two or more irregular rows of smaller spines appear on the higher parts of the anterior slope, the remainder of which is covered by a dense mat of pustules. The brachial ridges are seldom very clearly impressed on the shell and present no unusual features. The lateral loops are situated near mid- valve and just inside the fringe of endospines marking the lateral margin of the visceral area. Growth.—The youngest pedicle valves are nearly circular in outline, strongly convex, and somewhat keeled in the umbonal region. Such specimens were attached by one or more umbonal rings and perhaps by slight cementation at the beak. Many of the young show a deformity or cica- trix at the beak but this may be by impingement against the substrate rather than atachment. In any case the young of E. lateralis were attached and attachment rings appear on specimens as long as 9 mm. It appears, however, that after reaching a length of 10 mm, the individual attained most of its adult characters. The brachial valve is moderately concave, has dimples and a few wrinkles but is devoid of spines for at least its first 5 mm of growth. Between the 5- and 10-mm stages, spines appear on all of the margins except near the beak. Inside, the median septum is not defined until about the 5-mm stage and the bilobed cardinal process is nearly at right angles to the posterior margin and is deeply grooved anteroventrally. It thus forms a compressed triangle when viewed from the exterior. The groove on the ventral side becomes filled at the base during growth, and the median lobe of the cardinal process begins to become prominent in the 5- to 10-mm stage. Growth of spines on the young pedicle valve is interesting. While the valve is attached the body spines may equal or exceed the length of the spines on the lateral slopes. The body spines are long and curved over the anterior and anterolateral margins and may exceed the length of the body. Stratigraphy.—The origin of Echinauris is not now known; its superficial resemblance to Avonia suggests that it may have arisen from some related form in the Pennsylvanian. The earliest specimens here identified as Echinauris are those from the Uddenites-ht?ir\ng Shale Member described as E. subquadrata, new species. Two other species, both from the Wolfcampian, are similar to E. subquad- rata. This small group of species is not entirely satisfactorily placed in Echinauris because of peculiarities of the spine arrangement, but this seems to be the best assignment according to present knowledge. This type appears also higher in the Permian where is is represented by "Avonia" ore- gonensis Cooper and by Productus tuberculatus Moeller, from Russia. Another group of species in this genus is repre- sented or typified by E. irre guiar is, new species. These are generally small shells with a tendency to NUMBER 19 1003 ventral sulcation, development of interrupted cos- tae, and halteroid spines arranged in helter-skelter fashion. Others included in this group are Avonia subhorrida newberryi McKee, E. parva, new spe- cies, E. crassa, new species, and several undescribed species that are insufficient in number and pres- ervation. This group of species belongs mainly to the Leonardian. Echinauris lateralis Muir-Wood and Cooper, the type species of the genus, is the leading form of another stock which is characterized by the direct lateral extension of halteroid spines. This stock appears to be confined to the Road Canyon and Word formations and includes E. lappacea, E. liumbona, E. productelloides, and E. magna, all new species. The present list of species assigned to Echinauris does not exhaust the possibilities. The genus is common throughout Word equivalents in parts of western United States that are still poorly known paleontologically. It is common in Permian deposits in Utah, Arizona, Wyoming, Nevada, and Cali- fornia. Undescribed species are present in the Guadalupe Mountains of Texas and New Mexico. It seems to be found chiefly in limestone. In the Glass Mountains specimens of the E. irregularis group are commonly found in the biohermal limestones of the late Leonardian; the E. lateralis group, on the other hand, is generally found in dead-shell associations in sandy or dirty limestone. The Word formation has no biohermal associations. Grant (1968) presented an account of the living habits of species that lived apart from bioherms. The holotypes of some of the following new species are too fragile or too spinose to be measured accurately without serious damage. Dimensions can be estimated fairly closely from the photographs on the plates. Echinauris bella, new species Plate 326: figures 1-58; Plate 410: ficures 9-13 Small, young adults usually equal in length and width, old adults elongate oval in outline; deeply concavo-convex; sides gently rounded; anterior margin varying from broadly to narrowly rounded. Hinge usually equal to midwidth. Ears large, nearly at right angle. Surface mostly smooth but with few wrinkles just inside ears; concentric growth lines and few growth lamellae appearing on anterior slope. Halteroid spines long and slender, attaining length of 12.5 mm on specimen 8 mm long; halteroid spines concentrated on ears, posterior margin, and lateral slopes, usually extending later- ally but also irregular. Body spines shorter than halteroid spines, usually more slender, curved, ante- riorly overhanging brachial valve. Brachial valve with wrinkles on ears; moderately spaced hairlike spines covering entire surface. Pedicle valve unevenly convex in lateral profile, umbonal region strongly and narrowly curved, re- mainder moderately convex; anterior profile some- what narrowly domed, with narrowly rounded median region and long sloping sides. Umbonal region narrowly convex merging into strongly and somewhat narrowly inflated median region. Trail long, moderately convex and steep. Sulcus not de- veloped. Umbonal slopes precipitate; lateral slopes steeply inclined to precipitate. Brachial valve deeply concave, deepest in postero- median region; sides and anterior sloping steeply toward midvalve; ears concave and demarcated by strongly defined, oblique ridge. Pedicle valve interior with lightly impressed mus- cle field; ears without baffles. Brachial valve interior with sessile, bilobed car- dinal process; bilobation strong in ventral view but in posterior view inside edges of lobes forming poorly defined median lobe; lateral ridges nonexis- tent or poorly developed; ear baffles forming strong oblique ridge and, in some specimens, extended as low indistinct ridge anteriorly and medially around visceral region. Brachial ridge prominent, extend- ing obliquely anterolaterally from adductor field, looping inside row of moderately strong endospines. Adductor field consisting of two smooth, tear- shaped scars, ear indistinctly divisible into two scars. Breviseptum dividing adductor field, short, not reaching midvalve, distally free. Trail slope long and minutely granulöse. Stratigraphic Occurrence.—Cibolo Forma- tion, Road Canyon Formation. Localities.—Cibolo: USNM 738g, 738-1. Road Canyon: AMNH 509; USNM 702c, 703, 703a, 703c, 703d, 706f, 707e, 710u, 710z, 712t, 720d, 721o, 722g, 724a, 724b, 724j, 726d, 737q. Diagnosis.—Small Echinauris, with length and width nearly equal and spines fairly scattered. Types.—Holotype: USNM 154773b. Figured paratypes: USNM 149621v-z, a M *; 153492a-c; 153493; 154772a, b; 154733a, c. 1004 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 707e 149621a 10.8 7.7 20.0 9.8 10.9 6.6 3.1 149621b 10.3 ? 20.0 10.3 9.3 6.1 ? 149621c 10.0 ? 19.0 8.9 8.9 5.9 ? 14962Id 9.0 7.9 15.5 9.1 9.0 4.8 2.2 149621e 9.0 7.0 17.0 9.0 8.9 5.3 2.3 14962If 8.2 6.6 15.0 7.8 8.0 4.6 1.8 149621g 8.3 6.7 15.0 9.3 8.7 5.0 2.0 149621h 8.2 6.6 14.5 8.6 7.8 4.7 2.0 149621 i 7.7 6.2 14.0 7.9 8.0 4.5 1.6 159621J 8.1 ? 14.5 8.2 7.4 4.5 ? 149621k 7.3 5.7 13.5 7.3 7.2 4.3 1.6 1496211 6.9 5.7 12.4 8.2 7.0 3.9 1.2 149621m 7.7 5.9 13.5 6.3 7.4 4.2 2.1 14962In 6.6 5.3 11.5 5.9? 7.2 3.4 1.0 149621o 6.1 5.0 9.5 6.0 6.3 3.0 1.5 149621p 6.1 5.3 9.0 ? 5.9 2.8 1.4 149721q 5.7 4.7 8.5 5.1 6.0 2.9 1.3 14972lr 5.0 4.4 7.0 5.3 5.2 2.5 ? 149621s 4.9 4.4 6.5 ? 5.0 2.1 0.7 149621t 4.4 3.6 6.0 3.0 4.2 1.8 0.6 14962lu 3.4 2.8 4.0 2.3 3.0 1.0 0.4 154773b 8.5 6.5 ? 8.5 9.0 ? ? (holotype) * *Measuremen ts of holotype pedicle valve incomplete and approximate because of fragility of spines. Comparisons.—This is a fairly distinctive species because of its wide hinge, very delicate spines, and the random arrangement of the halteroid lateral spines. These features distinguish it from all other species of this genus. Externally, this little species suggests Krotovia but the spine arrangement is dif- ferent. Krotovia does not have large lateral spines and the body spines are in quincunx and closely matted, quite unlike those of E. bella. In its small size this species suggests K. barentzi (Milorado- vich) but that species is more strongly convex in lateral profile, the length and midwidth are not nearly equal, and the body spines are more crowded than those of Echinauris. Furthermore, the Glass Mountains species is much smaller than the Russian Arctic form. Discussion.—The cardinal process of E. bella is small but not in proportion to the small size of the shell. The process, when viewed from the ventral side, is distinctly bilobed; viewed from the dorsal side, it is bilobed and a median lobe is not clear. The valve is so deeply concave that the cardinal process myophore is parallel to the valve length and faces dorsad rather than posteriorly. A median lobe is indistinctly formed by coalescence of the in- ner sides of the two lobes, and in old specimens the processes are trilobate. The cardinal process thus suggests that of the Leioproductidae. A callus or platform is formed between the cardinal process and the adductor field. Commonly a ridge extends anterolaterally from it to bound the outside mar- gins of the inner, elongate adductor scars. A second pair of ridges extends anterolaterally on the outside of the smaller and rounded outer scars. The lateral ridges extend from the outside of the posterior platform obliquely across the ears. These are strong ridges but they become lower anteriorly to swing around the lateral margins of the visceral disc and across its anterior margin. This demarca- tion of the visceral disc is a reminder of the margin of the Marginiferinae but it is seldom strongly de- veloped. The breviseptum arises near the posterior end of the adductor field, divides that field into two parts, and just anterior to it, ascends from the floor to jut out free as a sharp projection. The distal end of the septum does not quite reach midvalve. The adductor field consists of two parts, a me- NUMBER 19 1005 dian part of two smooth scars and an outer part on each side consisting of an indistinct rounded outer scar. The two inner scars have smooth surfaces, are elongate triangular in outline, and in some speci- mens are clearly divisible into two scars. The brachial ridges in most specimens are well developed. These originate at the anterior inner edge of the outer adductor scar and descend antero- laterally roughly parallel to the ear baffles or lateral ridges. They are narrowly looped on the posterior side of the band of strong endospines that occurs on the anterior edge of the visceral disc. Echinauris cf. E. boulei (Kozlowski) Plate 367: figures 1, 2 Productus boulei Kozlowski, 1914:47, text-fig. 13, pi. 3: figs. 8, 9. [Not Avonia boulei (Kozlowski) King, 1931:82, pi. 20: figs. 7-9, = Echinauris interrupta, new species.] Large for genus, transversely to longitudinally el- liptical in outline; sides rounded to nearly straight; anterior margin broadly curved. Anterior commis- sure in old specimens slightly and narrowly de- flected in dorsad direction. Surface with moderately long (about 12 mm) spines on both valves, those of pedicle valve sparsely to moderately abundantly scattered over surface and with narrow anterior elongated elevations; spines on lateral slopes not differentiated in size from those on shell body. Brachial valve spines concentrated peripherally, and in vicinity of ears. Pedicle valve strongly convex in lateral profile, most convex part in umbonal region. Anterior pro- file broadly and moderately convex and with long, steep slopes. Umbonal region swollen, not strongly extended posteriorly in young specimens but con- siderably extended in old specimens. Beak small and narrowly pointed. Median region of the young, faintly sulcate in young adults. Brachial valve deeply and evenly concave, snugly fitting pedicle valve; umbonal region deeply de- pressed; ears strongly deflected but small. Pedicle valve interior with broadly flabellate di- ductor muscle scars; adductor track not thickened. Brachial valve interior with broadly bilobed, low cardinal process and strong lateral ridges rising proximally to base of cardinal process. Adductor field broad, not thickened in specimen USNM 153483a, but having curved ridge along anterior margin. Median septum low and slender. Measurements (in mm).—From locality USNM 725z, specimens 153483a and b, respectively: length 22.0, 24.0; brachial value length 15.9, 16.3; mid- width 26.0, 27.3; hinge width 15.4*, 23.0; thickness 4.6, (?). Stratigraphic Occurrence.—Hueco Canyon Formation (just above the Powwow Conglomer- ate). Locality.—USNM 499b = 725z. Diagnosis.—Moderately large Echinauris with poorly developed spines on the lateral slopes and ears and with strong development of longitidinal costae. Type.—Figured specimen: USNM 153483a. Discussion.—It seems best to refer the specimens on which the above description is based to Kozlow- ski's species. They agree with Kozlowski's figures in details of the interior, in size, and in profiles. These Texas specimens are somewhat more sparsely spi- nöse and are more costate than the Andean species. The Hueco Canyon specimens are larger and less umbonate than E. interrupta from the Lenox Hills Formation. Echinauris circularis, new species Plate 335: figures 1-35 Small for genus, nearly circular outline, hinge narrower than midwidth; ears small and incon- spicuous; anterior commissure without dorsad fold. Beak small and inconspicuous. Halteroid spines few, located on ears and lateral slopes. Body spines distant, fairly long, slender, sent off at high angle. Spine bases not forming ridges. Brachial valve with numerous hairlike spines. Pedicle valve strongly convex in lateral profile and highly domed in anterior profile; umbonal re- gion broadly swollen but not extending far poste- rior to hinge; median region strongly and broadly inflated; trail convex, with steep slope. Brachial valve with poorly defined ears and great depth, sides and posterior sloping medially, deepest at midvalve. Pedicle valve interior with muscle scars poorly impressed. Brachial valve interior with small, sessile cardinal process; muscle scars slightly thickened and breviseptum low and short. Stratigraphic Occurrence.—Cathedral Moun- tain Formation. Locality.—USNM 72lu. 1006 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).—Thickness unmeasur- able. brach- ial sur- valve face hinge mid- length length length width width heigl USNM 721u 152725a 8.7 7.4 15.0 7.5 8.8 5.1 152725b 8.8 7.0 15.0 8.0 9.3 5.0 (holotype) 152725c 7.6 6.5 11.5 7.4 8.2 3.8 152725d 10.0 8.7 17.0 8.3 10.7 5.3 Diagnosis.—Nearly circular Echinauris with nar- row hinge and swollen valves. Types.—Holotype: USNM 152725b. Figured par- atypes: USNM 152725a, c-g. Comparison.—The circular form and swollen pedicle valve distinguish this species from E. parva, new species. Echinauris circularis is most like E. bella, new species, but is slightly larger, has a narrower hinge generally, and more swollen pedicle valve. Many specimens of E. bella tend to have a somewhat carínate umbonal region, whereas that of E. circularis is broadly swollen. Echinauris crassa, new species Plate 327: figures 1-36 Small for genus, subquadrate in outline, wider than long; sides slightly oblique to gently rounded; anterior margin very broadly rounded; ears promi- nent; hinge wider than midvalve; pedicle valve sur- face marked by fine growth lines and occasional short, elongated spine bases anterior to spines. All spines stout, differentiation between halteroid and ornament spines not clear, except for position; body spines attaining length of more than 10 mm; spines few in number, well scattered. Brachial valve exte- rior marked by few large, scattered dimples and scattered spines. Pedicle valve in lateral profile strongly convex, maximum convexity in mid region. Beak small; umbonal region broadly swollen and prolonged prominently posterior to hinge in adults. Median region swollen; trail gently convex but sloping steeply to margin; flanks rounded and steep. Brachial valve evenly and moderately concave with steep lateral and anterior rims. Ears flattened, prominent. Measurements (in i mm).—Echinauris crassa, new species: brachial surface hinge length valve length length width midwidth height thickness USNM 703a 152708a 12.6 8.4 ? 13.1 13.1 ? 5.2 (holotype) 152708c 9.3 7.0 18.0 12.8 10.0 6.1 3.6 152708e 12.0 ? 24.0 14.7 13.2 7.7 ? Stratigraphic Occurrence.—Cathedral Moun- tain and Road Canyon formations. Localities.—Cathedral Mountain: USNM 702, 71 lq, 714w, 723u, 723v. Road Canyon: USNM 702c, 703a, 721y, 724d. Diagnosis.—Small Echinauris with few, very stout spines. Types.—Holotype: USNM 152708a. Figured par- atypes: USNM 152708b-f; 154774a, b; 154775a. Discussion.—This is a rare species and only a few specimens are present in the collection. It differs from E. irregularis, new species, which it most re- sembles, in lack of interrupted costae, very strong spines well scattered over the venter and few in number. It is so unlike any of the other species described herein that further comparison is un- necesary. Echinauris interrupta, new species Plate 328: ficures 1-33 Avonia boulei R. E. King (not Kozlowski), 1931:82, pi. 20: figs. 7-9. Medium size for genus, slightly wider than long, somewhat quadrate in outline; lateral margins gently rounded; anterior margin broadly rounded. Anterior commissure not folded. Surface of pedicle valve smooth except for scattered spine bases, short and somewhat rounded in posterior region but be- coming elongated anteriorly to suggest interrupted NUMBER 19 1007 costae. Spines mostly slender, halteroid spines con- centrated on lateral slopes long and slender, but ornament spines short, curved, and slender, attain- ing length of about 10 mm (usually nearer 5 mm). Brachial valve with scattered dimples, and slender, erect spines scattered distantly over surface. Pedicle valve moderately convex in lateral pro- file, maximum curvature at about midvalve; ante- rior profile steeply domed, steep-sided. Umbo narrowly swollen, umbonal slopes steep, beak strongly incurved; ears obtuse, not well defined; median region inflated; trail gently convex; flanks rounded and steep. Median sulcus poorly defined or absent. Brachial valve deeply concave, producing very thin visceral region; concavity broad and deep, deepest at about midvalve; umbonal region deeply concave under beak; ears somewhat flattened but not strongly demarcated except by change of slope in posterolateral areas; anterior and lateral rims steep. Pedicle valve interior with moderately developed ginglymus in some specimens; ear baffles obscure. Brachial valve interior delicate for large shell; car- dinal process small; adductor field small, not thick- ened; median ridge low and endospines nearly uniform in size, small, delicate and covering ante- rior slope. Measurements (in mm).— brachial surface hinge length valve length length width midzvidth height thickness USNM 715 152709a 20.9 ? 35.0? 21A 23.4 10.5 152709b 19.6 ? 33.0 15.0? 21.4 11.1 152709Í 15.0 ? 23.0 14.0 17.0 7.0 152709h ? 16.9 ? ? 21.7 ? 152709Í ? 14.0 ? ? 20.3 ? 152709k 19.8 ? 33.0 15.8? 21.4 10.0 USNM 701 d 152710e 18.8 14.0 31.5 15.0 20.7 9.9 2.9 (holotypc)* #Holotypc too fragile to measure; dimensions estimated from photographs plate 328. Stratigraphic Occurrence.—Neal Ranch and Lenox Hills formations. Localities.—Neal Ranch: King 193; USNM 701, 701c, 701d, 715b, 721g. Lenox Hills: 707m, 707n, 713y, 715. Diagnosis.—Subrectangular Echinauris with wide hinge, scattered, elongate spine bases and short, slender ornament spines. Types.—Holotype: USNM 152710e. Figured paratypes: USNM 152709a; 152710a, b, i-1. Comparison and Discussion.—This is an uncom- mon species in the Glass Mountains and seldom is found silicified. It is most numerous in the goniatite bed in the midst of the 60 feet of shale in the Lenox Hills Formation on Dugout Mountain. Echinauris interrupta is one of several species having a similar habit which is clearly echinaurid but not entirely typical. Generally this group con- tains fairly large shells; but the spines, both orna- ment and halteroid, are more slender than would be expected in shells of this size. Furthermore, the halteroid spines are about the same diameter as the ornament spines. Two species of this group appear in the Glass Mountains, that under discussion and E. subquadrata, new species. A third possible species occurs in rocks of Wolfcampian age in the Hueco Mountains. Echinauris boulei (Kozlowski), when compared with E. interrupta, presents a number of obviously different features. It is much more spinose and the exterior of the brachial valve is more numerously pitted than that of the Glass Mountains specimens. Furthermore, the posterior of the Peruvian speci- mens is more acuminate than that of the Texas material. In addition to these features, the height of E. interrupta is greater than that of E. boulei. Echinauris subquadrata, new species, also sug- gests E. interrupta, but in that species the umbo is less swollen above the hinge and is even broader than that of E. interrupta. The venter and trail of 1008 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY E. subquadrata are less spinose than those of E. interrupta. Echinauris interrupta seems to be characteristic of the Lenox Hills Formation but its occurrence in the upper part of the Neal Ranch Formation sug- gests a relationship between this part of the Neal Ranch and the Lenox Hills Formation. Echinauris irregularis, new species Plate 329: figures 1-24; Plate 330: ficures 1-43; Plate 331: FicuRES 1-34; Plate 332: figures 25-32 Avonia subhorrida rugatula R. E. King (not Girty), 1931:84, pi. 20: fig. 14. Small, subcircular to subrectangular in outline, length and width nearly equal; hinge wide, gener- ally about equal to midwidth but seldom wider than midvalve; sides gently rounded to nearly straight; anterior margin gently rounded, rarely broadly emarginated. Ornament consisting of growth lines, sporadically developed elongated ridges lying anterior to spines on trail, and irregular wrinkles on pedicle valve. Brachial valve with growth lines, scattered wrinkles, and scattered, shallow dimples. Spines consisting of halteroid and ornament spines, former bunched on lateral slopes and laterally or irregularly developed; ornament spines curved, long but seldom reaching length of halteroid spines. Pedicle valve moderately convex in lateral pro- Measurements (in mm).— brachial surface h in ge length valve length length width midwidth height thickness USNM 702b 154776a 10.8 8.5 ? 12.0 12.0 7.5 ? (holotype) USNM 702 152711a 13.5 9.7 26.0 16.4 14.0 8.4 4.7 152711b 12.9 9.3 25.0 15.5 14.9 9.0 5.2 152711c 12.2 9.9 23.0 11.9 13.4 7.6 4.6 152711d 11.9 9.2 22.5 121 11.5 7.4 1.4 152711e 10.6 8.5 17.5 9.6 10.3 5.3 3.3 152711f 8.3 7.1 13.0 7.3 9.9 4.1 2.0 152711g 7.9 7.0 12.0 5.8 8.5 3.8 1.7 152711h 7.4 6.6 10.0 5.5 7.7 2.3 1.3 15271H 6.1 ? 8.5 5.7 5.9 2.4 ? USNM 703b 152714a 14.9 10.6 32.0 14.2 15.6 10.1 ? 152714b 16.9 10.8 34.0 13.7 17.4 10.6 ? 152714c 12.4 9.2 24.0 11.7 13.0 7.8 5.1 152714d 11.2 9.7 20.0 10.3 12.2 (3.9 ? 152714e 10.0 7.7 19.0 8.6 10.1 6.0 3.5 152714Í 6.8 6.0 7.0 5.0? 7.7 2.1 1.4 USNM 703a 152713a 14.1 9.0 29.0 14.0? 13.5 9.0 ? 152713b 11.3 7.6? 22.0 9.7 12.5 7.6 ? 152713c 10.7 ».2 20.0 10.8 11.6 6.1 3.6 152713d 9.3 7.5 16.0 8.0 10.8 5.5 2.6 USNM 702c 152712a 13.5 10.3 25.0 14.0 14.8 8.4 5.5 152712b 14.6 9.6? 30.0 15.0 13.7 10.0? ? 152712c 12.2 9.2 24.0 11.8 13.1 7.3 3.8 152712d 10.8 7.7 21.5 11.3 11.6 7.0 3.3 152712e 10.0 7.7 17.5 10.5 11.1 5.7 2.7 152712f 7.9 6.6 12.5 7.4 8.2 3.5 1.4 152712g 5.7 4.8 6.5 4.7 5.9 2.0 1.3 152712h 4.7 4.2 5.0 ? 4.9 1.6 0.9 152712J 7.9 5.9 11.0 7.3 8.6 3.4 2.2 NUMBER 19 1009 file, posterior narrowly convex; anterior profile nar- rowly domed, with steep sides. Beak small, umbonal region varying from slightly elongated behind pos- terior margin to greatly elongated; visceral hump strongly swollen; trail long, inflated and moder- ately convex; median sulcus variably developed, usually scarcely defined. Flanks well rounded; ears small, flattened to gently convex, varying from acute to obtuse but usually nearly right angle. Brachial valve concave with maximum concavity at middle or slightly anterior, margins steeply ele- vated; umbo shallowly depressed; ears flattened but ridges setting them off not strongly developed. Pedicle valve interior with slightly thickened ad- ductor field and inconspicuous ear ridges. Brachial valve with adductor field strongly thickened in adults, interior scars larger, ranging in shape from teardrop-shaped to triangular; median septum prominent; cardinal process usually with bulbous myophore; lateral ridges usually only slightly de- veloped; endospines small. Stratigraphic Occurrence.—Bone Spring, Skin- ner Ranch, Cathedral Mountain (Wedin Member) and Road Canyon formations. Localities—Bone Spring: AMNH 591, 678. Skinner Ranch: USNM 727a. Cathedral Moun- tain: AMNH 500, 500C, 500F, 500H, 500N, 500X; USNM 702, 702a, 702b, 702ent, 702-low, 702un, 703a1, 703b, 703bs, 708, 711q, 712o, 72lu, 723k, 723p, 723u, 726o, 726u, 726y, 733m, 735b. Wedin Member: USNM 700-1, 700x, 714v, 714w, 717e, 723v, 727p. Road Canyon: AMNH 501, 503; USNM 702c, 703a, 703c, 703d, 706f, 707e, 709c, 719x, 721j, 721s, 721y, 724a, 724b, 724j, 726z. Diagnosis.—Small Echinauris with fairly numer- ous strong spines on body, lateral spines irregular, interruptedly costate on trail. Types.—Holotype: USNM 154776a. Figured paratypes: USNM 154776b; 154777a-i; 154778a-c; 154779a-k; 154780a; 154781a, b; 154786a-g; 154787a-e; 154788a-c; 154789a. Measured para- types: USNM 15271 la-i; 152712a-h, j; 152713a-d; 152714a-f. Comparison and Discussion.—Specimens of small Echinauris are fairly common in most of the levels of the "Leonard Formation" of the King brother's first report (in P. B. King, 1931) representing about 300 feet of section. This includes zones character- ized by Institella, Torynechus, and Edriosteges. Naturally, in a span of sediments representing a fair amount of time, considerable variation is en- countered. Deviation appears in the arrangement and size of spines rather than in dimensions, which seem re- markably uniform in generous lots from the four principal localities. The spines vary in length and diameter on the body of the shell and more promi- nently on the lateral slopes, where the long hal- teroid spines are located. These are not all directed laterally as they are in E. lateralis Muir-Wood and Cooper but may take off in almost any direction. Regardless of direction they seem to have served the purpose of steadying the shell on the sea bottom or anchoring it in mud. Echinauris irregularis suggests a larger E. parva, new species, but the latter species appears to be proportionately wider, although the spine arrange- ment of the two is very similar. Size is an important distinction between the two species because E. ir- regularis is almost twice the size of E. parva. Echinauris crassa, new species, suggests E. ir- regularis but is not so costate anteriorly and its spines are much thicker, stronger, and less numer- ous. Echinauris lappacea, new species, is about the same size as E. irregularis, but its umbonal region is not so strongly swollen as that of the Leonardian species, the spines are thicker and less numerous on the pedicle valve and are thicker on the brachial valve as well, but more densely crowded. Echinauris liumbona, new species, also suggests E. irregularis, but, like E. lappacea, the body spines are stronger and thicker, the umbonal region is generally nearly smooth, and the specimens are somewhat wider pro- portionately to E. irregularis. Avonia subhorrida newherryi McKee (1938) in- cludes specimens approximately the size and form of E. irregularis. Although no interiors of this sub- species are now known, its exterior characters place it with Echinauris and it is provisionally assigned to that genus. The spines are not preserved and their bases are not distinguishable on most of the type specimens. All but one of the specimens in McKee's type lot of 7 specimens are wider than long and have the umbonal region extended con- siderably beyond the hinge. The pedicle valve is fairly strongly sulcate, with the sulcus originating on the venter. This feature is a distinction from most specimens of E. irregularis. Interrupted costa- tion is plain on most of the specimens and is some- what coarser than that encountered in the Glass 1010 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Mountains species. The spines, from what can be seen of their bases, appear to have been well scat- tered and slender, somewhat more so than in E. ir- re guiar is. The form, size, and ornamentation of A. subhor- rida newberryi seem to have little in common with the type specimens of E. subhorrida (Meek). It is suggested, therefore, that McKees species be known as E. newberryi. Echinauris lappacea, new species Plate 336: figures 1-31; Plate 476: figures 1-18 Small for genus, wider than long, subrectangular in outline; sides gently rounded; anterior margin nearly straight; hinge variable, usually not equal to midwidth; ears small, angular. Pedicle valve with scattered spines of nearly equal size, except on lateral slopes, there longer and directed somewhat posterolaterally; brachial valve with large spines around margin directed medially and forming mat over valve; small erect spines covering remainder of valve. Pedicle valve strongly and fairly evenly convex in lateral profile; maximum convexity in posterior third; anterior profile domed, dome flattened on top but with very steep sides. Beak small, umbonal region not greatly swollen in adults, considerably more so in old specimens. Median and posterome- dian regions strongly swollen; sulcus shallow and inconspicuous, originating on trail and extending to anterior margin, there causing slight flattening. Trail long, gently convex; flanks rounded and steep. Brachial valve moderately deeply convex, greatest convexity near midvalve; umbonal region more deeply concave and separated from flattened ears by low oblique ridges. Lateral and anterior rims steep. Pedicle valve interior with little thickening of adductor field; ears concave but ear baffles moder- ately developed, striated. Brachial valve interior with small and delicate cardinal process, adductor platform moderately thickened and endospines forming one prominent row. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 707e 152715a 13.3 11.3 22.0 15.0 15.8 8.0 4.0 152715b 13.0 10.8 19.0 14.4 14.9 7.0 152715c 12.2 9.3 23.0 15.0? 15.0 7.5 152715d 12.7 10.2 23.5 13.0 13.3 7.7 4.2 152715e 10.9 ? 19.0 11.4 13.3 6.7 152715Í 11.3 ? 23.0 12.0 11.4 7.5 152715g 18.0 12.4 33.0 16.6 16.2 10.8 6.0 152715h 13.2 ? 24.0 11.8 13.5 7.7 152715Í 10.0 8.0 18.0 10.9 11.4 6.0 (Fragile holotype not measured.) Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USNM 703, 703d, 706f, 707e, 709c, 710u, 720d, 721j, 721o, 721r, 721w, 721x, 721y, 721z, 722e, 722v, 723x, 724b, 724c, 726d, 726e, 732j, 736x. Diagnosis.—Subrectangular Echinauris with low umbonal region, coarse scattered ornament spines, and thick mat of spines on brachial valve. Types.—Holotype: USNM 154822d. Figured paratypes: USNM 152715c, 154520a-f, 154821a, 154822a-c, 154823a-e, 154824a, 154825a. Discussion.—This suggests E. liumbona, new species, from approximately the same stratigraphic level. It differs in its more nearly square outline, less swollen umbo, thicker spines, and nearly com- plete lack of interrupted costae-like spine bases. The brachial valve is quite different from that of E. liumbona because it is covered by a dense mat of spines, the larger ones crowding the margins and overhanging midvalve. Echinauris lateralis Muir-Wood and Cooper is much larger, with somewhat more scattered spines, NUMBER 19 1011 somewhat finer spines in comparison to those of E. lappacea, and with a less dense concentration of spines on the brachial valve of E. lateralis. Echinauris lateralis, Muir-Wood and Cooper Plate 333: figures 1-34; Plate 334: figures 1-33; Plate 335: figures 36-51; Plate 468: figures 5-9 Avonia subhorrida R. E. King (not Meek), 1931:84, pi. 20: figs. 10, 11. Echinauris lateralis Muir-Wood and Cooper, 1960:222, pi. 68: figs. 1-13. Medium size, subpentagonal to elongate, subrec- tangular in outline in adults but transversely sub- rectangular in juveniles; ears small, not usually extending beyond midwidth. Sides moderately rounded, anterior margin nearly straight, medially to gently rounded; anterior commissure unfolded. Spines of two kinds; halteroid spines long and ex- tending laterally to posterolaterally, attaining length of nearly 2 inches (5 cm); ornament spines more slender and shorter than halteroid spines, curved anteriorly and attaining length of nearly 1 inch (2.5 cm). Brachial valve with spines of two sizes; thick and heavy spines around the margins, curving abruptly medially; finer spines arising from valve surface at high angle, usually not extending beyond shell margin. Surface of pedicle valve with sparse wrinkles and fine growth lines, but radial marks few and consisting of short ridges anterior to spines, best developed, if at all, in old adults. Brachial valve surface marked by occasional wrin- kles and growth lines but also by scattered dimples corresponding to larger spines of opposite valve. Pedicle valve strongly convex in lateral profile, maximum curvature in posterior third; anterior profile narrowly domed and with precipitous sides. Beak small, incurved and protruding beyond hinge; umbo narrowly swollen; posteromedian region strongly swollen; trail long and fairly strongly curved; median region depressed from place of geniculation to anterior margin by shallow, fre- quently barely discernible sulcus. Flanks rounded and steep. Brachial valve deeply and evenly concave, maxi- mum concavity near midvalve. Umbonal region shallowly depressed; ears flattened and separated from main concavity of valve by oblique ridge. Pedicle valve interior with long adductor plat- form moderately elevated; ears with low baffle and deep longitudinal groove in adults. Brachial valve interior with bulbous cardinal process having longi- tudinally thickened shaft in adults, moderately thickened adductor field, strong breviseptum, and anterior slope covered by endospines lessening in size and strength anteriorly. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 706e 149698a 23.4 14.4 51.0 19.8 22.0 15.3 8.0 149698b 21.6 13.5 43.0 22.4 22.0 13.7 6.0 149698c 19.8 13.0 37.0 19.0 21.0 12.0 6.6 149698d 18.8 12.8 41.0 16.2? 19.0 13.6 8.4* 149698j 15.8 13.3 35.0 18.0 18.8? 11.0? 6.5 149698k 11.8 9.9 19.0 11.4 15.4 6.0 3.3 1496981 8.5 7.6 12.0 6.0 8.9 3.4 1.8 149698m 8.3 7.1 13.0 7.4 9.0 3.8 2.3? 149698n 4.3 3.4 6.0 2.9 3.9 1.4 0.8 149698o 22.9 ? 48.0 19.0 21.8 15.2 ? 149698p 15.3 ? 21.5 14.6 18.9 8.2 ? 149698q 12.9 ? 20.0 12.9 15.6 5.7 ? 149698r 10.2 ? 15.5 8.4 11.9 4.5 ? Stratigraphic Occurrence.—Road Canyon For- mation, Word Formation (China Tank, Willis Ranch, Appel Ranch members, and lenses between the last two). Localities.—Road Canyon: USNM 713, 716xa. Word: USNM 737b, 741 p. China Tank: USNM 703e, 706, 706c, 706z, 726r, 733q. Willis Ranch: AMNH 505, 506; USNM 706, 706e, 718d, 723t, 1012 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 724u, 735c. Lenses: 706b, 732c, 737w, 742b. Appel Ranch: 704, 706d, 714o, 715i, 719z, 726t. Diagnosis.—Medium Echinauris with length and width nearly equal, faintly sulcate, with well scat- tered body spines, and longer nearly straight hal- teroid spines extending laterally. Types.—Holotype: USNM 124052a. Figured par- atypes: USNM 124052c-e, g, j. Unfigured paratypes: USNM 124052b, f, h, i, k. Figured hypotypes: USNM 149696a-e; 149697a-z, a'-g'; 149699; 153916. Measured hypotypes: USNM 149698a-d, j-r. Comparison and Discussion.—This species is abundant in the Word Formation (Willis Ranch Member), which yields excellently preserved speci- mens from mere spat to old adults, but is rare in the other limestone members of the formation. The youngest specimens are about 2 mm long and are nearly circular. They are provided with a small ring of spines at the umbo and undoubtedly were attached to parental spines or other small round objects. Attachment rings may be preserved in specimens up to 10 mm in length, but they are rare in specimens that large. Echinauris lateralis also suggests E. liumbona, new species, but the Road Canyon species is smaller and has longer and more curved body spines. Echinauris subhorrida (Meek) has been widely identified and specimens of E. lateralis have been placed under this name. The size of the two species is about the same, but the Phosphoria species has on the pedicle valve a conspicuous sulcus lacking in E. lateralis. Furthermore, from a study of spine bases on the type specimen, the spines of E. sub- horrida appear to have been finer than those of E. lateralis, more numerous, and to have been more liberally provided with elongated bases than the Word species. Comparisons with E. lappacea, and E. productel- loides, both new species, are made under those species. Echinauris liumbona, new species Plate 337: figures 1-36 Small to medium, subquadrate in outline; length and width approximately equal; sides rounded; an- terior margin slightly emarginate. Anterior com- missure with slight dorsad flexure. Ears small, form- ing approximately right angle. Ornament spines of pedicle valve long and stout, attaining length of about 15 mm. Halteroid spines about same diameter but not thickly developed on lateral slopes. Bra- chial valve with dimples; stout spines around ele- vated rim and ears, less common in midvalve. Pedicle valve with uneven lateral profile, greatest curvature on visceral hump and umbonal region. Anterior profile forming steep-sided dome flattened somewhat on top. Umbonal region strongly ele- vated posterior to hinge, with few spines or spine bases; posteromedian region strongly swollen; trail convex, with steep slope; sulcus originating on an- terior side of visceral hump, shallow, inconspicuous but extending to anterior margin, there forming slight indentation. Flanks narrowly rounded and with precipitous sides. Brachial valve deeply concave, most concave in median region; ears well demarcated by slope change in posterolateral regions; lateral and ante- rior rims steep, median fold barely perceptible. Pedicle valve interior with adductor field not thickened; ear baffles well developed. Brachial valve interior with small cardinal process on thick- ened platform; lateral ridges strong; slopes to ears striated; adductor field small, moderately thick- ened. Endospines moderately large in one or two rows. Measurements (in mm), able. -Thickness unmeasur- length brach- ial sur- valve face hinge mid- length length width width height USNM 703d 152716a 14.8 10.2? 32.0 18.2 17.6 10.2 152716b 15.6 10.6? 32.0 15.2 16.7 10.4 152716c 14.0 9.6 31.0 14.7 14.8 9.8 152716d 12.1 8.4 26.0 13.1 14.1 7.8 152716c 10.4 8.6 21.0 11.0 13.4 6.4 152716f 7.6 6.6? 12.0 7.0 9.4 4.2 152716g ß.O 4.9? 8.0 5.8 7.0 2.4 152716h 13.0 9.7 25.0 12.2 14.6 8.0 152716o 12.4 ? c.27.0 13.0 14.0 8.5 (holotype) Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—AMNH 503; USNM 703, 703c, 703d, 721j, 721z. Diagnosis.—Subrectangular Echinauris with few spine ridges, emarginate anterior, and naked or nearly naked umbones. Types.—Holotype: USNM 152716o. Figured paratypes: USNM 152716-1, 154826a-e, 154827a. NUMBER 19 1013 Unfigured paratypes: USNM 152716a-k, m, n. Mea- sured paratypes: USNM 152716a-h. Discussion.—This species is most like E. lateralis Muir-Wood and Cooper but has some resemblance to larger individuals of E. irregularis, new species. It differs from the former in not being so umbonate, in having longer, curved ornament spines, and hav- ing the halteroid spines less strongly differentiated than they are in E. lateralis. It differs from E. ir- regularis, new species, in having a different size and shape, not always detectable in some crushed in- dividuals, in having few and subdued elongate spine ridges, and much less umbonate pedicle valve. Echinauris productelloides, new species, resem- bles E. liumbona but is larger, not strongly um- bonate, is more swollen, and has its maximum con- vexity nearer midvalve. Like E. productelloides the spines of both kinds are of about the same diameter, but those of E. liumbona are longer and more curved on the body. Furthermore, the umbonal re- gion of E. productelloides is moderately spinose. Avonia dorsoconcava McKee from the Kaibab Limestone of the Grand Canyon region appears to belong to Echinauris and suggests E. liumbona. It differs, however, in having a fairly strong sulcus in the pedicle valve, the strongest sulcus yet seen in the genus, in having fairly strong interrupted costa- tion on the trail, and a narrow umbonal region. The nature of its spines is unknown. Echinauris magna, new species Plate 338: figures 1-27 Pústula subhorrida Branson (not Meek), 1930:32, pi. 8: figs. 9-11. Large, generally somewhat longer than wide or with width and length nearly equal; outline gener- ally quadrate; hinge usually about equal to mid- width but varying in individuals; sides rounded; anterior margin broadly rounded; anterior commis- sure slightly folded dorsally. Ears small, triangular, prominent, usually acutely angular. Surface of pedicle valve with umbonal region and visceral hump fairly closely covered by spines, their bases forming rounded nodes; anterior slopes and trail marked by narrow and elongated spine bases situ- ated anterior to spines; ornament spines erect or curved, slender on flanks but those occupying sulcus stronger, larger, and erect. Halteroid spines stouter than ornament spines, about equal in diameter to median spines, long, directed posterolaterally, com- monly irregular. Spines of brachial valve, erect, nu- merous over valve surface; slopes of anterior rim irregularly costate. Pedicle valve strongly convex in lateral profile, maximum convexity in posterior third. Anterior profile with nearly vertical sides and sulcate dome. Umbonal region strongly elevated and extending posterior to hinge for a fourth to a fifth of valve length. Umbonal region and visceral hump strongly swollen; trail long, strongly convex in both profiles; sulcus conspicuous, originating on umbo or visceral hump and extending to anterior margin. Flanks bounding sulcus swollen and with precipitous sides. Brachial valve deepest in median region, with strongly elevated rims; ears demarcated by oblique ridge, narrowly concave on dorsal side. Fold low, not always clearly visible, but, when well developed, forming dorsad fold in anterior margin. Pedicle valve interior with elongated and thick- ened adductor field. Ear baffles prominent and thickened, strongly striated; interior extensions of spines prominent on lateral slopes. Brachial valve interior with bulbous myophore on cardinal process Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 722c 152717a 32.4 19.8 62.0? 27.4 30.0 21.0? 11.6 152717b 29.9 17.4 60.0 31.8 29.0 20.0 9.1 (holotype) 152717c 24.0 17.2 52.0 ? 26.6 17.3 9.8 152717d 26.2 20.0 56.0 33.8 30.4 18.3 10.4 152717e 25.4 19.3 15.2 ? 28.2 17.0 8.2 152717Í 26.6 18.8 56.0 30.3 27.3 17.8 ? 152717g 22.4 16.1 46.0 26.4 25.0 15.1 7.7 152717h 27.5 18.0 53.0 32.4 27.5 16.8 8.4 1014 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY but shaft scarcely discernible. Adductor field small, moderately thickened; breviseptum thin, bladelike, strongly elevated, highest at anterior extremity. En- dospines small, forming mat on slope anterior to breviseptum; brachial ridges well formed. Stratigraphic Occurrence.—Phosphoria For- mation (Franson Member). Localities.- USNM 722a, 722b, 722c (= 762), 722d, 760, 762. Diagnosis.—Large Echinauris with numerous fine spines and numerous narrow, interrupted, elongate spine bases on the trail; sulcus strong and with row of large spines up midline of pedicle valve. Types.—Holotype: USNM 152717b. Figured para- types: USNM 152717d, i; 154828a-g; 154829a. Un- figured paratypes: USNM 152717a, c, e-h. Mea- sured paratypes: USNM 152717a, c-h. Comparison and Discussion.—This is the largest of the known species of Echinauris and seems to be fairly common in the Phosphoria Formation of Wyoming where it has long passed under the name of Horridonia subhorrida (Meek). Comparison of silicified specimens of E. magna with the lectotype of E. subhorrida shows the former to have a stronger median sulcus, stronger interrupted costation, and somewhat different spine arrangement. The spine bases of the lectotype of E. subhorrida are not well preserved, but this specimen seems to lack the row of large spines up the valve center as in E. magna (see discussion of E. subhorrida below). Some of the larger forms of E. lateralis Muir- Wood and Cooper, such as those occurring in the lens just above the Willis Ranch Member of the Word Formation (USNM 706b), have some resem- blance to E. magna when the interrupted costae are fairly strong. These never attain the strength of those of E. magna and the species does not attain the maximum size of E. magna. Furthermore, the spine arrangement on the two species is different, and the sulcus of the pedicle valve is narrower and not so strong as it is in the Phosphoria species. Echinauris parva, new species Plate 332: ficures 1-24 Small, wider than long, rectangular in outline with well rounded sides and gently rounded ante- rior margin. Hinge narrower than midwidth; ears small, approximating right angle. Pedicle valve sur- face marked by growth lines and distant oblique ornament spines attaining length on venter of 10 mm; halteroid spines located on lateral slopes and ears, usually irregular in direction, commonly curved, attaining length of 25 mm. Brachial valve with scattered dimples and erect spines, those of ears commonly directed anterolaterally to cover middle of valve. Pedicle valve strongly convex in lateral profile, posterior slope steeper and more curved than ante- rior slope; anterior profile domed, with steep sides but flattened crest; beak small; umbo not strongly elevated beyond hinge; median and umbonal re- gions strongly inflated; lateral slopes steep. Trail flattened to faintly sulcate medially. Brachial valve deeply concave, with steep lateral rims; umbonal region concave; ears flattened and demarcated from concave valve by abrupt slope change. Pedicle valve interior with slightly thickened ad- ductor field; ear baffles not pronounced. Brachial valve interior with strong lateral ridges and thick- ened cardinal process shaft; and adductor field small Measurements (in mm).—Echinauris parva, new species: brachial surface hinge length valve length length width midwidth height thickness USNM 716x 152718a 9.1 7.3 18.0 9.1 10.4 5.7 2.7 152718b 8.5 6.2 15.0 8.3 P-2 5.0 2.8 152718c 7.6 6.2? 14.0 7.2 9.1 4.8? ? 152718d 7.7 6.7? 14.0 ? 8.8 4.4 2.3 152718e 6.4 5.5? 8.0 5.0 7.0 2.7 1.5 154834f 8.0 6.4 14.0 7.7 8.8 5.2 3.2 (holotype) NUMBER 19 1015 but much thickened. Cardinal process myophore small; breviseptum strong; endospines large. Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—AMNH 503; USNM 703, 703c, 716x. Diagnosis.—The smallest of the known Echinau- ris with delicate spines, those of the lateral margins (halteroid spines) irregular in direction. Types.—Holotype: USNM 154834Í. Figured para- types: USNM 152718e, 154834a-e. Comparison and Discussion.—This small and delicate species has been seen only in the Road Canyon Formation. It is most suggestive of young forms of E. irregularis but it is wider than speci- mens of that species of the same size. Echinauris productelloides, new species Plate 339: figures 1-35 Medium size for genus, wider than long, roundly elliptical outline; sides well rounded but anterior margin nearly straight. Ears small, demarcated by slight sinuation of lateral margin, approximating right angle. Pedicle valve with scattered, curved, tapering ornament spines attaining length of at least 12 mm. Halteroid spines long and slender, about same diameter as bases of ornament spines; spine bases short and narrow. Brachial valve exte- rior with fine, even erect spines scattered over whole surface. Pedicle valve fairly evenly and moderately con- vex in lateral profile; maximum convexity near midvalve; anterior profile broadly domed and slightly depressed medially, sides of dome having steep slopes. Beak small, umbo only slightly ex- tended posterior to hinge; umbonal and median regions broadly swollen; anterior slope steep; me- dian region of anterior slope flattened to faintly sulcate; flanks rounded and with steep slopes. Brachial valve moderately concave, deepest near middle; lateral and anterior rims fairly steep; ears concave, demarcated by low ridges. Pedicle valve interior with slightly thickened ad- ductor field; ears flattened; ear baffles forming slen- der ridges. Brachial valve interior with small cardinal process, slender and curving lateral ridges, and scarcely thickened adductor field. Measurements (in mm).—Thickness unmeasur- able. brach- ial sur- valve face hinge mid- length length length width width height 152719a 16.7 12.4 30.0 15.9 18.0 10.0 152719b 15.6 12.0 28.0 16.0 17.7 9.0 151719c 13.5 11.5 24.0 12.3 14.3 7.2 152719d 10.9 9.2 16.5 10.3 11.4 5.2 152719e 8.0 7.1 11.5 ? 9.2 3.5 152719f 4.9 3.8 8.0 ? 5.6 2.1 152719g 15.9 12.4? 31.0? 17.0 19.6 10.0 (holotype) 152719h 14.9 11.9 30.0 15.0 17.9 10.0 Stratigraphic Occurrence.—Cherry Canyon Formation (Getaway Member). Localities.—Moore locality 31. AMNH 21, 28, 496, 512, 519, 600. USNM 728, 730, 732. Diagnosis.—Echinauris of medium size with all spines of about equal diameter and strongly swollen venter. Types.—Holotype: USNM 152719g. Figured paratypes: USNM 152719e, g-1; 154830a; 154831a, b; 154832a. Measured paratypes: USNM 152719a-f, h. Unfigured paratypes: USNM 1527l9a-d, f. Discussion.—This is not a common species in the Getaway Limestone Member and strongly sug- gests E. lateralis Muir-Wood and Cooper. It differs from that species in its strongly swollen venter, the maximum convexity of which occurs near midvalve. The spines are different from those of E. lateralis because both types of spines have about the same diameter, the halteroid spines are thus long and slender; whereas the ornament spines are short, curved, and slender. The spines are also somewhat more numerous on E. productelloides than on the Glass Mountain species. Echinauris subhorrida (Meek) Productus subhorridus Meek, 1877:75, pi. 7: fig. 3a [not 3 and 3b].—Girty, 1909:265. This species has not been identified in the Glass Mountains but varieties and subspecies of it have been named in the Guadalupe Mountains and the name has been used in the Glass Mountains. It is therefore important to identify this species positively and to indicate its range as clearly as possible. 1016 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY The types are preserved in the U. S. National Museum of Natural History (15144) and are labelled as Carboniferous from Moleen Peak, Ne- vada. In the lot are 16 specimens, but they come from other places besides Moleen Peak; the 2 that concern us chiefly are those figured by Meek (1877, pi. 7: figs. 3, 3a and 3b). The specimen represented by figures 3 and 3b are of the same individual, which may be identi- fied by its nearly complete outline, deep sulcus on the pedicle valve, and nearly complete absence of spines bases, although they are abundantly depicted in the two figures. The other specimen, illustrated by figure 3a, is incomplete anteriorly, is somewhat crushed, but does exhibit abundant spine bases. This specimen is not so strongly arched as the previous one and the two appear to us to be entirely different specifically and probably also generically. Although this species has been abundantly cited in the literature, the type selected by Girty (1909, p. 265) has generally been overlooked. According to the USNM catalogue of types Schuchert (in Merrill, 1905) gives the location of the entire lot (USNM 15144) as Moleen Peak, Nevada, but the lectotype is labelled Mahogany Mountain, Egan Pass, Egan Mountains, Nevada, and this locality is also listed by Meek (1877). A single specimen from Moleen Peak, Elko Range, west side of Long Valley appears to have nearly the same features as the lectotype. This is true also of a specimen from the Wachoe Mountains, Nevada. Many specimens from various parts of the Perm- ian have been referred to this species without ref- erence to the types. Furthermore, a number of varieties or subspecies have been created which ap- pear not to be related. For example Productus sub- horridus rugulatus Girty appears to be referrable to Costispinifera rather than Echinauris because of its strongly rugose visceral disc. This variety was also identified by R. E. King (1931) in the Glass Mountains. His specimens are clearly a mixed lot but they seem to have affinities with Echinauris, some belonging to E. lateralis Muir-Wood and Cooper, but others of uncertain relationship be- cause of poor preservation. McKee (1938) proposed a subspecies Avonia sub- horrida newberryi for specimens from the Kaibab Formation of the Grand Canyon. These definitely seem referable to Echinauris but the species is a small one not very similar to E. subhorrida. Its affinities seem rather with E. irregularis, new species, from upper Leonardian rocks of the Glass Moun- tains than with the much younger Phosphoria species. In naming his species "subhorridus" Meek per- petuated an unfortunate misconception, saying, "In its smooth surface, deep mesial sinus, and strong spines, this species resembles the narrowest varieties of Productus horridus of Sowerby." He also pointed out the size difference between the European and British species when compared to the American one, and he indicated an age difference which is now known not to be true. After Sowerby's species P. horridus was made the type of the genus Horridonia Chao, many American authors uncrit- ically placed Meek's species and ones like it in Chao's genus. The slightest comparison of any of these American shells with specimens of Horridonia, which is large, nearly smooth, and has its few spines almost wholly confined to the hinge area of both valves, would convince these authors that they were not dealing with Horridonia. This name has thus been introduced into the American literature for a genus which appears to be rare in the United States (except Alaska). Horridonia is not related to Echinauris; it is a dictyoclostid whereas Echin- auris has affinities with the Marginiferidae. Echinauris subquadrata, new species Plate 340: figures 1-22 Large, subquadrate in outline; wider than long, hinge about equal to midwidth; anterior margin broadly rounded; sides more strongly rounded. Surface mostly smooth but with distantly scattered, short spine bases on pedicle valve; spines short, curved, fairly stout and reaching 10 mm in length; brachial valve marked by large, distant pits or dimples and slender, scattered, delicate spines, especially on rim slopes and ears. Pedicle valve moderately convex in lateral pro- file, maximum curvature in posterior half; anterior profile broadly domed and with steeply sloping sides. Beak small, umbo broad and spreading, not strongly protruding posterior to hinge; median region broadly swollen; anterior slope moderately NUMBER 19 1017 Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 705h 152720 20.4 ? 35.0 24.6 25.0 11.3 ? USNM 701f 152721 20.3 16.4 33.0 21.3 24.0 10.2 4.0 USNM 701c 152722 19.8 14.6? ? 24.7 25.0 10.5 ? (holotype) long and steep: median region from visceral hump to anterior margin flattened or marked by barely perceptible broad sulcus; flanks rounded and steep. Ears prominent, approximately forming right angle. Brachial valve deeply concave but with moderate elevated rim; most deeply concave in median region; ears somewhat flattened and gently concave. Interiors not known. Stratigraphic Occurrence.—Gaptank Forma- tion (Uddenites-bearing Shale Member), Neal Ranch Formation (bed 9 of Cooper = bed 14 of P. B. King), Lenox Hills Formation. Localities.—Uddenites: USNM 701 f, 70lu, 703o, 705h. Gaptank: USNM 701y, 713e. Neal Ranch: USNM 701c, 701d. Lenox Hills: USNM 705, 707m. Diagnosis.—Echinauris of large size with short and slender ornament spines, broad umbo, and swollen venter. Types.—Holotype: USNM 152722. Figured paratypes: USNM 152720; 152721a,b; 154833a. Measured paratypes: USNM 152720, 152721. Discussion.—This species may be confused with E. interrupta, new species, or E. boulei (Kozlow- ski). It differs from the former in having less markedly interrupted costae on the trail, a less produced and much broader umbonal region, and in being proportionally much wider. All these differences from E. interrupta also distinguish this species from E. boulei. Echinauris subquadrata is uncommon in the U ddenites-bearing Shale Member of the Gaptank Formation and in the lower to middle parts of the Neal Ranch Formation. It serves to emphasize the essential continuity of the Gaptank and Neal Ranch formations. Two silicified specimens from "Bed 12" of P. B. King (1931), which forms the crest of the ridge on the west front of the Wolf Camp Hills, are here identified with unsilicified specimens from the Uddenites-bearing Shale Member. The silicified specimens preserve the spines and give a good idea of the appearance of this species in life. These two specimens have the same broad outlines and spreading umbonal region exhibited by their earlier relatives. Echinauris venustula, new species Plate 341: figures 1-56 Small for the genus, squarish in outline, sides well rounded and anterior margin broadly rounded to slightly emarginate. Anterior commissure usually straight but some with slight dorsad fold. Hinge usually narrower than midwidth; Ears small and approximating right angle. Surface smooth but with occasional concentric wrinkles and low ridges ante- rior to small spine bases. Halteroid spines usually lateral, scattered on lateral slopes and ears, attaining length of 15 mm in specimen 10 mm long. Ornament spines sparsely scattered, shorter than halteroid spines, extending anteriorly at about 30°. Brachial valve with strong concentric wrinkles in posterior region and with numerous fine, scattered spines especially marginally where spines point medially; strongly dimpled in some specimens. Pedicle valve strongly convex in lateral profile, narrowest convexity at place of geniculation; trail long and gently convex; umbonal region strongly swollen, especially in old specimens. Geniculation occurring about 5 mm anterior to beak. Anterior profile narrowly domed, with steeply sloping sides. Sulcus barely perceptible, usually confined to trail. Beak overhanging posterior margin. Brachial valve deeply concave, greatest concavity 1018 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY at midvalve, all lateral slopes steep, even those of posterior. Ears small and narrow, grooved but not deeply. Pedicle valve interior with divergent and flabel- late diductor scars. Adductor scars central, elongate, slightly thickened, and not enclosed anteriorly by diductors. Ears abruptly deflected to form shallow shelf, edge forming ear baffle. Brachial valve with fairly large bilobed cardinal process having grooved shaft when viewed from ventral side; doral view showing median lobe folded posteriorly and bounded by grooves. Lateral ridge narrow but well developed; lophidium narrowly rounded. Median adductor pair thickened, tear- shaped; lateral adductor pair small and incon- spicuous; ear baffles fairly thick and strongly fluted toward exterior. Endospines forming one row of strong, fairly long spines and another row sporadi- cally developed; brachial ridges well developed, with strong elevated rim. Anterior slope finely spinose. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 726o 152723a 12.5 8.7 27.0 12.8 10.9 7.7 5.6 152723b 12.5 7.3 26.0 10.7 11.5 7.7 4.2 152723c 11.6 ? 25.0 11.8 12.4 7.5 ? 152723d 11.0 8.2 20.0 11.2 12.0 6.5 3.3 (holotype) 152723e 10.2 7.0 19.5 7.0 10.6 6.6 4.0 152723Í 9.7 7.0 17.0 8.4 10.1 6.2 3.5 152723g 7.5 6.0 12.5 6.2 8.3 3.9 2.1 152723h 6.6 5.7 10.0 5.3 7.4 3.0 1.2 152723Í 4.9 4.5 5.5 3.6 5.4 1.8 0.9 Stratigraphic Occurrence.—Cathedral Moun- tain Formation. Locality.—USNM 726o. Diagnosis.—Small, sparsely spinose Echinauris with faintly developed spine ridges. Type.—Holotype: SNM 152723d. Figured par- atypes: USNM 152723c, m; 154867a-k. Unfigured paratypes: USNM 152723a, b, e-1. Measured para- types: USNM 152723a-c, e-i. Comparison.—This species is most like E. parva, new species, from the Road Canyon Formation but differs in having more swollen pedicle valves with poorer developed sulcus and deeper brachial valves. The spines on E. venustula are less abundant and less crowded than those of E. parva. Discussion.—This species has been found only with Hercosia delicata, new species, at USNM 726o where it is abundant. The species is variable; in late stages of growth there is a tendency toward elon- gation as evidenced by specimen 152723a. Variation also appears in the density of the spines but they are seldom much crowded. Dorsal spines appear as early as the 4-mm stage of growth. Many specimens retain the early umbonal attachment spines into adulthood. Echinauris species unidentified Specimens of Echinauris not identifiable with any of the above species were found at the following localities: AMNH 369, 417, 492, ?520, 633, 634, 635, 658; USNM 700s, 700v, 702b, 702f, 702m, 702n, 704z, 705k, 707b, 707d, 707-1, 710d, 710z, 712t, 713d, 713m, 716o, 716xa, 720d, 721j, 721r, 721s, 721t, 722e, ?722f, 722h, 722j, 722-1, 723w, 725s, 725v, 725y, 726d, 726h, 726n, 726x, 738c. Genus Oncosarina Cooper and Grant, 1969 Oncosarina Cooper and Grant, 1969:9. Small, subcircular to subquadrate in outline, hinge usually equal to or slightly less than mid- width, rarely slightly greater than midwidth; cardi- nal extremities varying from obtuse to slightly acute; NUMBER 19 1019 strongly concavo-convex, pedicle valve strongly in- flated. Sulcus in pedicle valve faintly developed, if present. Surface unequally costate; posterior smooth to indistinctly reticulate; trail with strong rounded costae; ears and posterolateral areas concentrically rugose. Brachial valve likewise but without spines. Pedicle valve with spines on ears and on umbonal and lateral slopes; costae bearing long, anteriorly curved spines on crests. Brachial valve posteriorly flattened but strongly geniculated in anterior part; body cavity moderately deep. Pedicle valve interior with swollen and elongated adductor track; ear baffles fairly well developed and striated. Brachial valve interior with moderately large, sessile marginiferid cardinal process; adductor tracks tearshaped, thickened and excavated medially and anteriorly; breviseptum anteriorly elevated, not extending posterior to midvalve. Ear baffles well developed, extending laterally as subperipheral rim but not extending anterior to visceral region; en- dospines on anterior slope, thick and moderately long. Type-Species.—Oncosarina spinicostata Cooper and Grant (1969:9, pi. 5: figs. 24, 25). Diagnosis.—Rotund and tumid marginiferids with strongly costate trail and no sulcus or only a slight median depression on the pedicle valve. Comparison.—This genus is most like Elliottella, from which it differs in its rotund exterior, lack of or faint development of a sulcus on the pedicle valve, and a brush of spines on the lateral slopes. It also suggests Costispinifera in external appearance, especially in the strength of the concentric undula- tions on the brachial valve; but Oncosarina does not have spines on the brachial valve. The exterior ornament of Oncosarina suggests Semicostella of the Mississippian, but that genus has a more sharply geniculated brachial valve and a much less strong development of spines, besides having a shafted car- dinal process. Discussion.—This genus suggests Elliottella Stehli morphologically, but the expression of the shells, with their strongly rounded profile and lack of median sulcus on the pedicle valve, is distinctive. Furthermore, the species are thus far fairly restricted to the late Wolfcampian sequence. Only one species has been found favorably silici- fied; the location from which it was taken appears to be equivocal, but the anatomy is beautifully dis- played and also the growth of the shell. These details are discussed under O. spinicostata. Oncosarina rotunda, new species Plate 318: figures 1-26 Small, length and width nearly equal; sides gently rounded to nearly straight; hinge width approximately equal to valve width at middle; anterior margin broadly rounded. Ears small, nearly rectangular. Concavo-convex but with fairly deep visceral cavity. Surface costate and spinose; costae irregular, few, rounded, with interspaces narrower than costae. Visceral disc region of both valves marked by regularly arranged, narrow, concentric wrinkles, those of brachial valve interrupted by deep dimples corresponding to spines of pedicle valve. Costae cancellating wrinkles on visceral disc region of pedicle valve. Spines all halteroid in character; usually row on posterior margin terminat- ing at extremity of ears; tuft of thick spines on lateral slopes; body spines fairly numerous, scat- tered and erect. Pedicle valve strongly convex in lateral profile, most convexity in posterior half; anterior profile narrowly convex and steep-sided dome. Beak strongly incurved; umbonal region narrowly swol- len, extended fairly strongly posterior to posterior margin; visceral disc and midregions strongly swollen; umbonal slopes short. Sulcus scarcely de- veloped; when present, narrow and shallow. Flanks swollen and with precipitous sides. Brachial valve moderately concave, maximum concavity near midvalve, sides and anterior sloping moderately steeply; anterior third moderately to strongly geniculated to form costate trail. Ears small, demarcated by slight flexure toward pedicle valve. Pedicle valve interior with enormously thickened adductor platform widening anteriorly; no ear baffles. Anterior slope with elongated pustules. Brachial valve interior with large cardinal process, thickened adductor platform and prominent brevi- septum. Stratigraphic Occurrence.—Skinner Ranch Formation (Decie Ranch Member). Localities.—USNM 707a, 71 Id, 714t. Diagnosis.—Subcircular rotund Oncosarina with strongly sculptured brachial valve. Types.—Holotype: USNM 149819d. Figured 1020 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 714t 149819a 12.2 ? 23.0 11.7? 12.9 7.0 ? 149819b 11.0 7.9? 22.0 10.7 12.1 7.1 5.4 149819c 11.8 ? 23.0? 14.2 12.3 7.6 ? 159819d 11.0 7.8 23.0 10.6 11.1 7.8 5.4 (holotype) 149819e 9.9 ? 17.0 11.5 11.3 4.6 ? 149819f 11.7 9.2 22.0 10.6? 12.0 7.7 6.0 149819g 9.4 7.9 16.0 9.8? 11.4 5.4 3.1 149819J 10.2 9.2 17.0 9.8? 10.7 5.2 3.5 149819k ? 10.0 ? 11.9 13.8 ? ? 1498191 11.5? ? 23.0? 12.0* 13.8 8.0? 5.2 USNM 707a 149816 12.7 8.2 25.0 9.9 10.9 8.4 4.8 paratypes: USNM 149819a, b, g, j, p. Measured paratypes: USNM 149816, I49819a-c, e-1. Unfig- ured paratypes: USNM 149819c, e, f, h, i, k-o. Comparison.—This species is characterized by the rotundity of its pedicle valve not only in out- line but in profile. In most specimens the length and midwidth are almost equal and the hinge is usually about equal to the midwidth. Furthermore, the pedicle valves are strongly convex in lateral profile. This combination of characters generally separates this species from all others. It is also more strongly wrinkled concentrically on the brachial valve than usual in the other more transverse species. Discussion.—This is not a common species; it was taken with Scacchinella in the western part of the Lenox Hills. The specimens have not been found in good silicified condition, and most of them were obtained by breaking them from calcarenite. Oncosarina spinicostata, Cooper and Grant Plate 324: figures 1-42; Plate 419: ficures 44-47 Marginifera manzanica R. E. King (not Girty), 1931:87, pi. 21: figs. 22-24. Oncosarina spinicostata Cooper and Grant, 1969:9, pi. 5: figs. 24, 25. Small, transversely subrectangular outline, hinge equal to or slightly wider than midwidth in adults. Sides gently rounded to nearly straight; anterior margin broadly curved. Ears small, nearly rectangu- lar. Concavo-convex and with fairly deep visceral cavity. Surface costate and spinose, costae variable in number, size, and spacing, ranging from 10 to 18. Spines all of halteroid type; one row on posterior margin and one on ear extremity; concentration of spines on lateral slopes and scattered stout spines on shell body. Pedicle valve strongly convex in lateral profile and with posterior and anterior surfaces nearly par- allel; anterior profile strongly domed and with steep lateral margins. Umbonal region flattened in pro- file, somewhat narrowly inflated as seen from pos- terior and with short, steep slopes; median region inflated. Sulcus, when present, broad and shallow, originating on venter and occupied by two to four costae. Flanks well rounded. Brachial valve deepest medially, visceral disc strongly wrinkled, wrinkles interrupted by large dimples. Sides and anterior, steep. Trail usually short, strongly costate. Ears flattened. Pedicle valve interior with moderately developed adductor platform and poorly developed ear baffles. Brachial valve interior with variably developed cardinal process, small and bilobed in juveniles but stout and trilobed in adults. Adductor platform con- sisting of two plates tilted toward side and sepa- rated by breviseptum; lateral ridges varying from absent to moderately strong; ear baffles strong and continued anteriorly and medially to form indis- tinct submarginal ridge. Brachial ridges indistinct. Endospines few, but stout and long. Stratigraphic Occurrence.—Skinner Ranch For- NUMBER 19 1021 Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 707-1 149823a 11.6 9.9 22.0 11.0? 14.0 6.6 3.6 149823b 11.3 8.6 22.0 13.6 13.8 7.0 3.5 149823c 10.3 8.7 17.5 13.5 13.3 5.7 3.5 149823d 10.3 8.1 18.5 11.2 11.8 6.0 4.3 149823e 9.4 7.4 15.5 11.4 10.7 4.8 2.5 149823f 8.1 6.3 12.0 ? 9.2 3.8 1.5 149823g 7.1 5.7 10.0 6.8? 8.2 3.5 1.3 149823h 6.2 5.7 8.0 6.1? 7.2 2.7 0.7 149823Í 6.6 6.0 9.5 6.6 7.2 3.0 1.7 149823J 11.7 9.2 23.0 12.2 12.9 8.0 4.5 149823k 10.6 8.0 20.0 9.8 11.3 6.9 4.4 1498231 10.9 7.8 18.0 11.4* 10.7 6.0 3.0 149823m 11.8 10.2 21.4 12.4* 13.0 6.5 4.2 USNM 707ha 149825a 12.0 9.4 24.0 12.3 14.6 8.0 4.9 149825b 10.4 7.7 19.0 11.0 12.5 6.4 ? 149825c 9.8 7.8 16.0 10.2 12.4 5.3 ? 149825d 8.2 6.7 13.0 8.9 10.9 4.5 ? 149825e 7.9 6.2 14.0 8.0 10.2 4.7 2.9 149825f 7.8 6.2 11.0 7.3 7.7 3.9 2.1 149825g 5.2 4.1 7.0 4.0 5.2 2.2 1.3 149825h 13.0 8.6 27.4 15.2 13.0 8.3 4.4 USNM 708e 149827a 12.2 ? 25.0 13.5 13.0 7.1 ? 149827b 11.5 ? 20.0 13.8 13.8 6.1 ? 149827c 9.7 ? 16.0? 13.4 11.2 5.5 ? 149827d 11.5 ? 21.5 13.9 12.8 6.8 ? 149827e 9.4 ? 17.0 12.2 12.3 5.2 ? 149827f 10.0 ? 18.0 10.3 11.4 5.5 ? 149827g 10.6 ? 19.0 13.5? 13.0 5.4 ? 149827h 12.4 ? 25.0 12.1 12.3 7.3? ? 149827Í 9.6 ? 16.5 11.0 10.8 6.2 ? 149827j 7.5 ? 12.0? 8.8 8.7 3.9 ? 149827p 11.2 ? 20.0 14.5 14.2 5.7 ? 149827t 11.1 ? 20.0 14.2 14.1 6.5 ? 149827U 10.0 ? 17.0 12.4 12.1 6.0 ? 149827V 9.3 7.5 16.0 11.2 10.7 5.5 2.9 149827w 11.4 9.0 21.0 13.3? 14.1 6.9 3.9 mation (Decie Ranch, Poplar Tank, and Sullivan Peak members), Hess Formation. Localities.—Decie Ranch: USNM 707g = 707-1. Poplar Tank: USNM 707ha, 708e, 713r, 741k. Sullivan Peak: USNM 705o, 707, 714y, 729o. Skinner Ranch (base): USNM 712p. Skinner Ranch (top) : USNM 71 Or, 715f, 723h, 723-1. Hess: USNM 709g. Diagnosis.—Small Oncosarina with variable cos- tae on trail, strongly dimpled brachial valve, and variably rugose brachial valve. Types.—Holotype: USNM 149824=153884. Fig- ured hypotypes: USNM 149823b; 149825a; 149827p; 153884a-f; 153885a, b. Measured hypotypes: USNM 149823a-m, 149825a-h; 149827a-j, p, t-w. Comparison.—Although this species suggests Elliottella Stehli, it differs in details of the orna- mentation, in the abundance of halteroid spines on the lateral slopes, and in the different development of the cardinal process. It is intermediate in size be- tween O. rotunda, new species, and O. whitei (R. E. King). Its costation is more variable than that of the former and the costae are stronger and more elevated. The brachial valve is not so strongly and 1022 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY regularly rugose as that of O. rotunda. This species is smaller than O. whitei with less uniform cos- tation and less strongly developed concentric wrin- kling on both valves. Discussion.—This species has considerable in- terest because of the unusual attachments de- veloped in the young stages and the development of the cardinal process as shown by specimens from USNM 707ha. The spat were attached by a series of rings in the young stages to productid spines or other small objects. Specimens still attached to spines are present in the collection; furthermore, some of the spat attached to the rings of their brothers, the two becoming intimately entwined and usually misshapen. The pedicle valve umbo of the spat is usually distorted and thickened. In some it is flattened where the spines were unable to clasp a round ob- ject and worked their way along the surface of the substrate. These examples are less common than those in which the umbo is distinctly grooved and was anchored by a number of spines. The smallest specimens show that the first rings appeared at the umbo and that others were added forward as needed to fix the specimen more firmly. On speci- mens where many of the earliest formed rings are broken away, a scar that distorts the umbo remains and the later-formed rings appear on the anterior slope. In such specimens, in which the umbonal region is generally considerably thickened, a trace of the attachment host is left as a well-defined groove. In some examples the beak region is thick- ened and distorted, and the remnants of the rings appear as two prongs extended laterally from the beak. Many adults retain the grooves or callosities developed in youth during the attached stages. Some specimens of this species retained their at- tachment rings for a considerable period, at least until 5 mm of length had been attained. This species is variable in shape, some of the variation being attributed to crowding in early life. The cardinal process of O. spinicostata in its younger phases is strongly bilobed and reminiscent of the cardinal process of the Productellinae. In young specimens this structure is bilobed with each lobe deeply grooved. With advancing age, how- ever, the gap between the lobes is somewhat bridged by the development of a median lobe. This extra lobe is deeply indented when viewed from the ventral side; seen from the posterior, the process is definitely trilobed and distinctly marginiferid in its type, because the indented median lobe is inclined posterodorsally. Oncosarina whitei (R. E. King) Plate 244: ficures 32-37; Plate 310: figures 42-61 Marginifera? whitei R. E. King (part), 1931:90, pi. 23: figs. la-c. Medium size, wider than long and subrectangular in outline; hinge forming widest part of adults. Sides gently rounded to nearly straight; anterior margin broadly rounded. Ears large and flattened in adults, nearly rectangular in juveniles. Surface ir- regularly costate; costae narrowly rounded to broad, numbering 12 to 16, interspaces varying from nar- rower to as broad as costae. Spines all halteroid, numerous, stout on sides, slender on body: forming thick tuft on sides, few on posterior margin; numerous scattered spines on body. Pedicle valve variable in lateral profile, adult usu- ally fairly strongly convex, maximum convexity at venter, umbonal region flattened, trail slope long and gently convex. Anterior profile broadly domed, with moderately steep sides. Umbonal region broadly but moderately convex; median region in- flated. Sulcus variable, usually poorly defined, originating on venter, broad and flat, occupied by one to three costae. Flanks rounded but not well demarcated from venter and trail. Brachial valve strongly wrinkled in visceral disc and near ear, deeply dimpled over most of surface; fairly deep and with steep sides and anterior; ears flattened and defined by low, oblique ridge. Pedicle valve interior with strongly thickened adductor platform but ear baffles not strongly developed. Brachial valve interior with moderately large car- dinal process and strongly elevated adductor platform. Lateral ridges and ear baffles moderately developed. Breviseptum short. Stratigraphic Occurrence.—Hess Formation (Taylor Ranch Member). Localities.—USNM 702d, 702e, 702f, 702m, 713x, 716n, 716o, 722p. Diagnosis.—Large for the genus; strong costae on the trail and numerous concentric wrinkles in the umbonal and visceral regions of both valves. NUMBER 19 1023 Measurements (in mm).— length King 107 YPM 11685 14.0 (holotype) USNM 702m 149840 15.8 USNM 702f 149838 12.4 USNM 716n 149843 13.8 USNM 716o 149845a 16.8 149845b 12.3 149845c 11.5 149845d 13.2 149845e 11.2 149845f 12.2 149845g 12.0 brachial valve length 10.7 surface hinge length width midwidth height thickness 27.0 15.0? 15.9 9.5 6.0 11.5 28.0 ? 16.1 9.1 5.4 10.5 22.0 17.0 14.8 7.6 3.4 ? 25.0 17.0? 15.2 8.1 ? ? 28.0? 20.7* 17.4 10.6 ? 20.5 ? 15.2 7.1 ? 18.5 13.6* 13.7 5.9 ? 25.0 17.0* 17.1 6.7 ? 19.0 15.0* 13.7 5.4 ? 21.0 ? 13.6 6.8 ? 21.0 15.6* 13.8 5.5 Types.—Holotype: YPM 11685. Figured hypotypes: USNM 149838; 149840; 149843; 149845 c, d; 153195. Measured hypotypes: USNM 149838, 149840, 149843, 149845a-g. Comparison.—This species is most like O. ro- tunda, new species, in outline and profile but it is much larger and has much stronger costae on the trail. Discussion.—Oncosarina whitei is fairly common in the Taylor Ranch Member, but it is hard to ob- tain good specimens, and interiors are extremely difficult to find or to prepare. The type lot con- sists of three specimens, one from the Glass Mountains (R. E. King locality 107) and two from the Sierra Diablo (R. E. King locality 479). The Glass Mountain specimen is the holotype. The other two are excluded from the species, but others subsequently were found. The lithology in which they occur is extremely hard, contains scattered chert, and is a siliceous limestone. When subjected to hydrochloric acid, décalcification leaves a solid residue of silicious material retaining the form of the original piece. All of this must be picked or scraped off the specimens, a process usually destruc- tive of spines. The few brachial valve interiors obtained do not have anteriorly excavated adductor platforms, but they are greatly thickened and elongated as usual in the genus. The lateral ridge is fairly well de- veloped and has strong fluting on its outer side. Subfamily RETARIINAE Muir-Wood and Cooper, 1960 Marginiferidae having exterior geniculated in dorsal direction and visceral region reticulated; trail long, often tubuliform; brachial valve in- terior with ridges across ears, occasionally with lat- eral flange; anterior row of endospines present. Genera in West Texas: Kutorginella E.A. Iva- nova, 1951( = Retaría Muir-Wood and Cooper, 1960); and Thamnosia Cooper and Grant, 1969. This subfamily ranges into the Capitán Forma- tion of the Guadalupian, where it is represented by a large and highly specialized species. The two genera represented are closely related, differing chiefly in the spinosity of the pedicle valve. The subfamily Retariinae is retained even though it proved necessary to submerge the genus Retaría which inspired it in the synonymy of Kutorginella. Genus Kutorginella E. A. Ivanova, 1951 Kutorginella Ivanov, 1935:87 [nomen nudum],—Ivanova, 1951:329.—Sarycheva, ed., 1960:234. Retaría Muir-Wood and Cooper, 1960:231.—Williams et al., 1965:H482. Neoproboscidella Ivanova, 1949:47 [nomen nudum]. Deeply concavo-convex with brachial valve sharply geniculated; usually transversely rectangu- lar in outline, hinge equal to or greater than mid- 1024 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOL0GY width; pedicle valve sulcate; brachial valve with low fold. Pedicle valve trail nasute in old speci- mens. Surface costellate, with fine concentric undulations cancellating visceral disc of both valves, that of the brachial valve more strongly than other. Both valves spinose, spines consisting of ornament and halteroid spines. Ornament spines mostly in um- bonal and visceral disc regions, usually slender, moderately long and gently curved; halteroid spines on posterior margin, ears, in row at base of lateral slopes above ears, a few on anterior part of trail; halteroid spines usually long and stout, some attaining length of 40 mm, especially at base of lateral slopes and on anterior part of trail. Bra- chial valve with scattered, long, slender spines. Pedicle valve interior with elongate and slightly elevated adductor field and subflabellate diductor scars; posterior adductors dendritic. Ear baffles varying from obsolete to strong. Brachial valve interior usually with moderately long-shafted cardinal process, usually narrowly tri- lobée!, median lobe curved dorsally; cardinal process buttressed by thick ridge uniting with brevisep- tum; lateral ridges strong, uniting with strong ear baffles to form marginal ridge or flange extend- ing around visceral disc, strongly elevated in some species, less so in others. Adductor field large, sub- oval to subtriangular, posterior adductor scars large and dentritic, anterior scars small and smooth. Brachial ridges usually delicate; endospines usually small, fringing anterior end of flange or marginal ridge. Breviseptum slender, uniting with cardinal process buttress ridge, rising to crest distally and extending to edge of visceral disc. Types-Species.—Kutorginella mosquensis E. A. Ivanova (1951:329). Diagnosis.—Transversely subrectangular Pro- ductacea having a semireticulate visceral disc region, a few long halteroid spines, and an elevated flange on the sides of the visceral disc. Comparison.—The ornament and general ex- terior characters suggest the genera Alexenia and Tubaria, which occur in the Upper Paleozoic of Russia. Although the exterior of Alexenia is almost identical to that of Kiitorginella and the name has been used for Re tar ia—Kutorginella (Stehli, 1954, and Cooper, 1957a), the interior of the brachial valve is so unlike that of Kutorginella as to pre- clude any association. In Alexenia the cardinal process is buttressed by two long, thin, parallel plates that extend to midvalve. These are unique among the Productacea and clearly exclude this genus from relationship with Kutorginella. Probably they should not be left in the same family. Tubaria is another Russian genus in which the two valves strongly resemble Kutorginella but the anterior is drawn into a long tube that is far more strongly developed than the nasute extension of Kutorginella. The interior details of Tubaria are not now known and its family placement was based on exterior characters. It might be related to Tham- nosia which has a strongly nasute anterior. At any rate Kutorginella cannot be placed in that genus. Separation of Kutorginella and Retaría is no longer possible. The former genus cannot be said to be well known, its present description is quite sketchy and the few published figures do not permit objective independent analysis of its characters, because no spines are shown. One of the illustrated specimens is anteriorly nasute and strongly resem- bles some specimens of K. sullivanensis (R. E. King). The interior details of the brachial valve described for Kutorginella are identical to those of many of our specimens. The description of Ku- torginella by Sarycheva and Sokolskaja (1952:153) is not in complete accordance with that of Ivanova (1951:329). In the former description it is stated that the spines are small, and that one row occurs along the hinge line and another on the boundary of the ears, whereas Ivanova says that there is a row of spines on the slopes toward the ears. In view of these close similarities it seems only proper that the name Retaría be abandoned. Muir-Wood and Cooper (1960) did not have available the ex- tensive material on which the above remarks are based, and they felt that considerable uncertainty existed as to the true characters of Kutorginella. At the time they wrote they had few strongly nasute specimens of "Retaria." Conservatism was then ap- propriate, but now we are unable to separate these two genera. Discussion.—This is a distinctive genus, common in the Pennsylvanian and through the Leonardian stage of the Permian. Its exterior shape, profile, and ornament combine to make it easily recog- nizable. It is usually transversely rectangular in out- line, but one species, K. meridionalis (McKee), is squarer in outline than most. Usually it is provided with large ears that are widely extended but gen- erally narrowly rounded rather than alate. The lat- NUMBER 19 1025 eral profile of the pedicle valve is usually strongly rounded but that ol the brachial valve is sharply geniculated. The ornament of this genus is as distinctive as its shape. The visceral disc region of the pedicle valve appears to have somewhat finer and less crowded costellae than the trail area but the costellae are less cancellated in this region than those of the brachial valve. On the flatter or vis- ceral disc region of the brachial valve, narrow undulations are fairly closely crowded and give a finely reticulate pattern to the surface. This orna- ment is very characteristic and one of the helpful features in identification. The reticulate pattern does not extend to the trail. In some species this pattern is complicated by superposition of dimples corresponding to the spines of the pedicle valve. Most of the species are strongly sulcate, some less so than others, but a sulcus is invariably present. It originates near the umbo or on the visceral disc and usually extends to the anterior margin. The trail is costellate, with the costellae usually crowded and separated by spaces narrower than their width. Specimens with exceptionally long trails tend to still finer costellae or to their obsolescence. A feature common in old specimens is the narrowing and elongation of the trail to form a nose or partial trough, the brachial valve likewise becom- ing nasute. This feature occurs in most of the species found in the Glass Mountains. The spine arrangement is variable among the species. Kutorginella umbonata (Muir-Wood and Cooper) has a single row of long slender spines over the ears on the lateral slopes, whereas K. sullivanensis (R. E. King) is usually provided with a single long spine in this region. The ornament spines are usually slender, tapering, and curve an- teriorly. They are best developed in the visceral disc region of the pedicle valve, but a few appear on the trail. The halteroid spines are the most conspicuous on all of the species. Those on the posterior margin generally are small and the ears are commonly naked. The lateral slopes are a major site for hal- teroid spines. In species such as K. uddeni, new species, a curved row starts on each side of the umbo and extends to near the posterolateral extremity, increasing in size in this direction and the last one usually being one of the major spines in size. The anterior part of the trail is another site for the development of major halteroid spines. In K. um- bonata (Muir-Wood and Cooper) long halteroid spines appear in a bunch at the anterior end of the trail, but in K. sullivanensis, two large spines only appear at this place, one on each side of the sulcus. The spines on posterolateral extremities and on the anterior part of the trail appear to be the major steadying spines. Most of the trail between the large anterior spines and the visceral disc edge is generally devoid of spines or marked by a few ornament spines only. The shell may have rested chiefly on this part of the trail and have been steadied by the lateral and anterior halteroid spines. This spineless portion of the trail appears in the Glass Mountains species. The full spine ar- rangement of Pennsylvanian members of the genus is not known, except that generally a row of spines overhangs the ears. The brachial spines of all the species are similar. They are commonly long, slender, and hairlike, and appear to have a uniform diameter. Some concen- tration of these on the ears can be noted but on the remainder of the valve they are well scattered. The flange and cardinal process are distinctive features of the brachial valve interior. The car- dinal process, as in all productid genera, is variable, being long or short shafted depending on the species. The myophore is generally indented on the ventral face and is trilobed on the posterior face. It is typically marginiferid in having the median lobe deeply grooved and bent in a posterodorsal direction. The lateral lobes are generally narrowly compressed rather than widely extended. The car- dinal process shaft appears to be extended an- teriorly by the development at its anterior end of a buttress ridge, which extends to the proximal end of the breviseptum to which it is united. In young specimens the ridge and septum are distinct and separate plates. Lateral ridges of varying strength, usually strong, extend obliquely laterally from the ears. Ear baffles, a thin plate or flange, nearly upright or extended directly laterally, hang over the lateral trail area. The flange is narrow to fairly wide, extending an- teriorly to the anterolateral extremity where, in some species, it diminishes in width or disappears. The flange in other species is extended as a shelf over the anterior trail area to midvalve. Along its anterior margin the flange is serrated or spinose. The muscle area is usually variable in size and 1026 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY shape, but always consists of a large dendritic por- tion and a smaller, anterior, nondendritic area. In K. sullivanensis the adductor field is fairly'large and consists of two triangular patches, one on each side of the breviseptum. Most of the posterior of these patches is occupied by dendritic muscle scars, but the anterior angle of the triangle is formed by an elongate teardrop-shaped, nondendritic scar. Kutorginella dartoni (R. E. King) Productus dartoni R. E. King, 1931:67, pi. 10: figs. 12, 13. Small, subrectangular outline, longer than wide; hinge straight and wide, but widest part near mid- width; sides gently rounded; anterior margin broadly rounded; surface costellate, costellae num- bering about 5 per 5 millimeters at front margin; spines scattered on body and trail. Spine pattern not preserved. Ventral valve strongly but unevenly convex in lateral profile, greatest convexity about half-way anterior to beak, but posterior third somewhat flattened; anterior profile broadly rounded with long steep sides and median region depressed by narrow sulcus; umbonal region narrowly rounded and not greatly elongated in dorsal view; median region swollen; trail convex and long; sulcus origi- nating at umbo, narrow and shallow to anterior margin. Flanks rounded, sides steep; cardinal ex- tremities flattened and deflected into small ears; visceral region of dorsal valve finely reticulate. Dorsal valve gently concave in visceral region, strongly geniculated farther anterior; umbo and median region forming most concave part; flanks flattened; anteromedian part of visceral disc marked by low but indistinct fold. Ear baffles well devel- oped, anterior of visceral region inside the dorsal valve marked by low spiny ridge on margin. Measurements (in mm).—From King locality 460, lectotype YPM 10739: length 20.0?, dorsal length 14.6, midwidth 24.5, hinge width 19.8?*, thickness 11.4, surface length 41-K Stratigraphic Occurrence.—Hueco Canyon Formation. Locality.—R. E. King locality 460, South of Victorio Peak above Millican. Types.—Lectotype: YPM 10739. Selection of Type.—This species is based on two cotypes, YPM 10739, from the Hueco Canyon Formation, south of Victorio Peak above Millican (King locality 460), to which was attached a speci- men of Composita called C. mira, and YPM 10740, a pedicle valve from the "Lower Gym" Formation on the slopes of Juan Peak (King locality 385). The specimen of Composita was removed from inside the outer concave surface of the dorsal valve. The dorsal valve is thus revealed in most of its de- tail in YPM 10739. The specimen is so broken along the anterior and on the margins near the cardinal extremities that the ear baffles and the margin are exposed. This specimen (YPM 10739) is more re- vealing than that from Juan Peak, which does not show the dorsal valve or any details of the interior, and therefore is selected as type of the species. The type selected seems to be different from the "Gym" form which has a lower umbo but a more swollen ventral valve, a deeper sulcus, and a much more strongly reticulate ventral visceral region. Kutorginella robusta, new species Plate 350: figures 5-20 Large for genus, transversely rectangular in out- line; hinge wide; ears large and extended laterally beyond midwidth; sides rounded; anterior margin broadly rounded, occasionally producing nasute ex- tension. Anterior commissure with slight dorsad fold. Beak small, incurved. Surface marked by flatly convex, crowded costellae, about 8 per 10 mm at front of adults. Visceral disc regions of both valves strongly and finely reticulated. Spines on pedicle valve numerous, mostly slender and delicate but with a few large. Spines forming single row of 7 or 8 on lateral slope over ears in large adults, these spines becoming increasingly large anterolaterally; largest and longest one usually last row; body spines and those of visceral disc short and delicate; spines on anterior part of trail not numerous, usually del- icate but with occasional ones of about same diameter as last in lateral row. Ears usually without spines; posterior margin generally without spines. Brachial valve with numerous long, hairlike spines, concentrated or best preserved on lateral and an- terior slopes. Brachial valve strongly reticulated. Pedicle valve strongly and fairly evenly convex in lateral profile, and broadly domed in anterior NUMBER 19 1027 profile, top notched by median sulcus. Umbonal region swollen but not protruding strongly posterior to hinge; median region very strongly swollen; sul- cus originating on umbonal region, usually broad and shallow, becoming shallower near anterior margin and in few specimens disappearing to form flattened indistinct costellate area. Ears wide and narrowly rounded. Anterior slope steep. Trail long, with tendency to lobation in some specimens. Brachial valve with broad, shallow depression forming umbo; nearly flat or slightly concave for about two-thirds of length, there strongly genicu- lated at about right angle or slightly less. Ears flat- tened and defined by oblique ridge. Pedicle valve interior with elongated and thick- ened adductor platform in old shells, posterior part dendritic; diductor scars large and flabellate but not enclosing adductors. Ear baffle thin, oblique. Brachial valve with variable cardinal process, thin and delicate with depression on ventral face and bilobed myophore; developing to stout, knob- like process strongly bilobed and greatly thickened. Buttress ridge usually thin but variable, some be- ing thick but all uniting with breviseptum; adduc- tor scars forming two strongly dendritic triangular patches; breviseptum, when well preserved, low, bladelike and extended anteriorly as free point over anterior slope; brachial ridges laterally extended, usually not strongly thickened. Lateral ridges join- ing lateral flanges, these widest anterolaterally but extended medially only as two rows of short, stout spines. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 721 o 149887a 27.3 21.2 64.0 43.3? 42.8 21.0 12.4 149887b 25.7 22.6 57.5 39.4 38.0 19.7 10.6 149887c 27.8 22.4 ? 46.0* 27.8 18.5 12.2 (holotype) 149887d 25.2 21.9 54.0 48.0*? 39.3 17.3 9.0 Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USNM 719x, 72lo, 721s. Diagnosis.—Large Kutorginella generally with delicate spines and a spine row over the naked ears. Types.—Holotype: USNM 149887c. Figured paratypes: USNM 149886a, 149887d, 154025a. Mea- sured paratypes: USNM 149887a, b, d. Unfigured paratypes: USNM 149887a, b. Comparison.—This species is most like Tham- nosia anterospinosa Cooper and Grant and Ku- torginella umbonata (Muir-Wood and Cooper). The great mass of halteroid spines on the anterior of the trail characteristic of T anterospinosa is a ready means of separating it from K. robusta. Sep- aration from K. umbonata is fairly easy because that species is generally somewhat shorter and has a greater tendency to anterior lobation which is sel- dom seen in K. robusta. The lateral row of spines is usually 7 or 8 in K. robusta rather than five, and the trail spines are usually less strongly developed than those of K. umbonata. The cardinal process of K. umbonata is not so strongly developed as that of K. robusta. Discussion.—This species is obviously related to K. umbonata (Muir-Wood and Cooper) because it has a similar lateral row of spines and a tendency to anterior lobation. The latter never seems to ma- terialize in most of the specimens. A considerable difference can be noted in the development of the cardinal process of the two species. Both are narrow and slender in the young but that of K. umbonata remains long and slender throughout life in the majority of specimens. It also retains the median distal depression on the ventral face. In the develop- ment of the cardinal process of K. robusta the process swells distally and the myophore becomes bulbous when viewed from the ventral side and strongly trilobed, from the posterior or dorsal sides. Size does not always determine the degree of growth of the cardinal process. One fully grown brachial valve, fairly thickened and truly adult in every re- spect, has the cardinal process small and delicate, entirely like that of a juvenile. 1028 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Kutorginella sullivanensis (R. E. King) Plate 237: ficures 9-12; Plate 342: ficures 1-34; Plate 350: FIGURES 1-4 Productus dartoni sullivanensis R. E. King, 1931:67, pi. 10: fig. 14. About medium size for genus; transversely rec- tangular in outline; hinge forming widest part; ears large and narrowly rounded, convex on pedicle side. Anterior margin strongly nasute; sides sloping medially. Surface of both valves costellate and spinose. Lateral slopes of visceral disc region marked by few strong concentric rugae cancellating the costellae; visceral disc with narrowly rounded costellae; trail costellae broad and flattened, sep- arated by fine striae, numbering 4 to 6 per 5 mm on trail; nasute part of trail with costellae sub- dued to obsolete. Brachial valve with finely can- cellated ornament. Spines few on pedicle valve; a few small spines on posterior margin; large stout spine attaining length of 35 mm on lateral slope, slightly anterior to and above ear; two large, stout spines attaining length of about 35 mm on trail, just posterior to nasute extension; small widely scattered spines, few in number, on shell body. Brachial valve with scattered, long, hairlike spines. Pedicle valve unevenly convex in lateral profile, valve humped strongly anterior to midvalve, visceral region shorter than trail and moderately convex, trail long and gently convex. Anterior profile steep sided, domed, deeply indented on top. Umbonal and visceral regions moderately swollen, steep slopes to lateral extremities. Median region strongly convex. Sulcus originating near middle of visceral disc, narrow and deep, dividing shell into two lobes. Flanks bounding sulcus strongly swollen. Sulcus extending onto nasute portion but becoming ob- solete or nearly so. Nasute extention pointed in some specimens but generally narrowly truncated. Pedicle valve interior with moderately thickened and elongated adductor field. Ears without baffles but with spines along inner margin facing visceral region. Brachial valve with small, erect, and fairly long cardinal process buttressed by strong ridge joining or surrounding proximal end of breviseptum, in latter case producing three ridges near midvalve. Lateral ridges strong and elevated, uniting with strong ear baffles to form marginal shelf around entire visceral disc, shelf looping sharply posteriorly toward distal end of breviseptum. Anterior edge of shelf with numerous small spines. Adductor field large, formed of two triangular patches on each side of breviseptum, anterior angle of each triangle forming nondendritic adductor, remainder of tri- angle strongly dendritic. Brachial ridges not de- veloped. Stratigraphic Occurrence.—Road Canyon For- mation. Localities.—USNM 702c, 703c, 707e, 710u, 710z, 72 lr, 724b, 724j. Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 707e YPM 10767 19.0 14.0? 37.0 ? 24.5 13.5? ? (holotype) 149872a 19.7 15.2 35.0 30.4* ? 26.8 13.0 6.9 149872b 22.5 16.5 41.0 26.6* 22.4 14.3 9.1 149872c 21.0 15.4 37.5 23.4* ? 24.8 13.7 6.3 149872c! 18.7 13.0 40.0 26.2* 23.2 13.2 8.6 149872e 18.6 14.3 40.0 ? 23.4 13.3 8.0 149872Í 24.0 15.2 45.0 26.6* ? 27.8 15.9 10.6 149872g 20.9 15.6 37.0 ? 24.3 13.2 7.5 149872h 24.2 ? 39.0 24.0? 24.0 11.0 ? 149872Í 21.6 16.0 38.0 ? 24.3 14.0 8.0 149872J 19.8 15.8 40.0 31.2*? 29.0 13.4 7.5 149872k 21.0 17.3 37.0 28.6»? 28.4* 13.5 5.0 1498721 28.5 19.8 45.0 34.0* 31.0* 13.7? 8.0 NUMBER 19 1029 Diagnosis.—Strongly sulcate and nasute Kutor- ginella having two long trail spines and two long lateral spines. Types.—Holotype: YPM 10767. Figured hy- potypes: USNM 149871a-e; 149872e, h, l-o; 149879. Measured hypotypes: USNM 149872a-l. Comparison.—The few large halteroid spines are distinctive of this species and separate it easily from Thamnosia anterospinosa Cooper and Grant, which is multispinose, and from Kutorginella uddeni, which has a curved ring of spines on the lateral slopes. Comparison is thus left with K. umbonata (Muir-Wood and Cooper), which also has a few large halteroid spines on the lateral slopes and trail. The latter, however, is a larger and more robust species than K. sullivanensis (R. E. King), with a higher umbonal region, more broadly rounded lateral profile, and usually more numerous halteroid spines; moreover, K. sullivanensis is more sharply nasute and with less strongly developed broad pli- cation of the trail. Discussion.—Kutorginella sullivanensis is fairly common in the bituminous limestone on the long bench just south of Sullivan Peak. Many specimens are somewhat flattened from umbo to trail but nevertheless seem normally depressed. A few speci- mens preserve the exceptionally long halteroid spines that give a clear indication of the way in which the species must have lived on the sea bottom. Brachial interiors are usually fairly well pre- served but the brachial ridges are preserved only in four specimens. They extend anterolaterally from the adductor field and are looped near to the lat- eral base of the flange. In this species the lateral flange is unusually wide and is set at a high angle to the visceral disc surface. The area surrounding the adductor field is finely pitted. The cardinal pro- cess is generally small and narrowly compressed. Kutorginella uddeni, new species Plate 343: figures 1-17 Medium to large for genus, transversely subrec- tangular in outline; hinge forming widest part; ears prominent, flattened. Lateral margins gently round- ed; anterior margin broadly rounded, usually faintly indented medially. Profile plano-convex with brachial valve strongly geniculated. Surface of both valves costellate, pedicle valve spinose; visceral region marked by distant concentric undulations crudely cancellating the costellae; trail with about five costellae in 5 mm near anterior margin. Bra- chial valve with numerous concentric rugae about same width as costellae, producing fine and prom- inent reticulation. Spines numerous on pedicle valve: few spines along posterior margin; row of five or six curving over ears at base of lateral slopes; few oblique spines on visceral disc; numerous spines scattered over trail and arising from costellae; no spines seen on brachial valve. Profile unevenly convex, greatest convexity at venter about midvalve, umbonal region slightly curved, trail gently convex. Anterior profile form- ing broad medially depressed dome. Umbonal region strongly inflated and with steep slopes to lateral extremities. Median region strongly inflated and humped. Sulcus originating on visceral disc, fairly narrow, usually shallow and extending to an- terior margin. Flanks bounding sulcus moderately inflated and with steep sides. Brachial valve nearly flat for about two-thirds of length, there abruptly geniculated to form nearly vertical slopes. Trail long and strongly costellate. Umbonal region shallowly depressed. Ears flattened and demarcated by oblique flexure toward pedicle valve. Fold barely perceptible, originating near midvalve. Pedicle valve interior with small adductor plat- form and large flabellate diductor scars. Ears flat- tened and without baffles. Brachial valve interior with narrow cardinal pro- cess deeply indented on ventral side, trilobed on dorsal side, median lobe bent posterodorsally. Car- dinal process buttressed by thickening surrounding proximal end of breviseptum. Lateral ridge low, joining large ear baffles continuous anteriorly to anterior end of visceral disc. Adductor scars not strongly thickened. Posterolateral areas pitted. Anterior of visceral disc with small endospines. Brachial ridges not seen. •Stratigraphic Occurrence.—Gaptank Forma- tion (Uddenites-bearing Shale Member), Neal Ranch Formation, Lenox Hills Formation. Localities.—Gaptank: USNM 701y. Uddenites: 701e, 701p, 701q, 701t, 701v, 702n, 703-1, 721h, 721i. Neal Ranch: 701, 701c, 715b. Lenox Hills: 707m, 713y, 715, 720z. Diagnosis.—Kutorginella with a row of spines 1030 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (in mm).— brachial surface hinge length valve length length width midwidth height thickness USNM 701q 149866a 22.3 ? 43.0 29.8? 29.5 13.0? ? 149866b 20.0 ? 39.0 26.0* 27.3 13.0 ? 149866c 21.0 13.7 42.0 ? ? 14.6 11.0 USNM 701e 149857a 25.6 ? 50.0? 32.4? 29.2 15.0 ? USNM 701 149855a 22.8 16.0 43.0 26.4? 27.3 15.2 6.0 + (holotype) USNM 721i 149865a 20.4 15.4 36.0? ? 30.0 13.3 9.2 curving at the base of the lateral slope from the umbo to the posterolateral extremity. Types.—Holotype: USNM 149855a. Figured par- atypes: USNM 149857a, 149866a, 153906a, b. Measured paratypes: USNM 149857a, 149865a, 149866a-c. Unfigured paratypes: USNM 149866b, c; 153906a. Comparisons.—This, like other Glass Mountains species of Kutorginella, has a row of halteroid spines over the ears extending from the umbo to the pos- terolateral extremity. In this respect it is like K. lasallensis (Worthen) of the Pennsylvanian and is probably closely related to it. It differs from that species in having a fuller and more rounded lateral profile, longer and more curved trail, the umbonal region less extended posterior to the hinge, and more swollen median region. Discussion.—Specimens of Kutorginella are fairly common in the Uddenit^-bearing Shale Member of the Gaptank Formation, but it is difficult to find them favorably mineralized in limestone. Kutorginella umbonata (Muir-Wood and Cooper) Plate 343: ficures 18-33; Plate 344: figures 1-30 Retaría umbonata Muir-Wood and Cooper, 1960:231, pi. 70: figs. 1-15. Large for genus, transversely elliptical to subrec- tangular in outline; hinge forming widest part; ears large, narrowly rounded, moderately to strongly convex. Sides rounded, sloping medially. Anterior margin broadly rounded and broadly plicated. Both valves costellate and spinose. Visceral disc slopes with few strong rugae crudely cancellating the cos- tellae; four to six costellae per 5 mm on trail; cos- tellae variable, in some specimens increasing in width anteriorly and becoming broad and flattened, but in others increasing in number at front by in- tercalation. Spines of two sizes: small, with elongate bases on visceral disc and posterior; and large halteroid spines on lateral slopes and trail. Halter- oid spines forming row of five increasingly large stout spines from base of lateral slope over ear around anterior margin of trail to opposite ear; row of five spines at base of lateral slopes and over- hanging ear, last and largest spine in this row form- ing first spine of horizontal row; ears spineless or with few small spines. Brachial valve with numer- ous rugae inside ears and with numerous, delicate, long scattered spines on entire shell, including ears. Pedicle valve with narrowly humped lateral pro- file, visceral disc region short and fairly strongly rounded, trail region about twice length of visceral disc and moderately rounded. Anterior profile broad dome, with steep sides and indented deeeply in middle. Visceral disc moderately inflated and with steep lateral slopes; median region inflated. Sul- cus originating on umbonal region, deep and wide but deepest in middle; flanks bounding sulcus in posterior and media