SbX 1926 INVERT. ZOOL. SMITHSONIAN INSTITUTION AMEIRICAN SILUEIAN CRINOIDS BY FRANK SPRINGER LAS VEGAS, NEW IVlEXICO ASSOGIATE IN PALEONTOLOGY, U. S. NATIONAL NIUSEUM (Publication 871)  ¢.-,, - PUBLISHED CITY OF WASHINGTON BY THE S/VIITHSONIAN INSTITUTION 926 BALOEIMORE MD.» U. S. A. CONTENTS INTRODUCTION ...... Erly Geologists .... The Tennessee Area . The Indiana Area ............................................... 6 The New York Area ........................................... 7 The Foreign Silurian ................................................ 8 Origin of the work .................................. 9 Collections used ......................................... Acknowledgments .............. 1 Order CAMERATA ................. Family DI MEROCRINIDAE ............................. 12 Dimerorrimts ........................................ F..tdim«rocrimts, new genus ............................................................. Cyphocrimts ................................... 14 Gaaacrin us .......... Lamptcrocrimts ............................. 19 (;enus and spccics indct. Family RHODOCRINIDAE .............................................. 22 lParaga:acrimts, new genus .......................................... 2_2 lP«ulocrinus, new genus .................................. 22 llïlsonictqm«s, new genus ..................................... 23 Eudimerocrinus, new genus .......... 24 Gcmtx and spccics itdct ............................... 24 L yriocrimts ................................. 24 Family [ELOCRINIDAE 25 J[acrostylocrinus ........................................ 25 Melocrim,s ..... 27 Cytocrinus ....................... Mariacrin us .... 28 . lllocrinus .................. 3o t'atclliocrimts .............................. Gcnus and species indet ................... 32 Laurclocrinus, new genus ... 32 CIonocrinus ............................. 34 Family C.«LrPOCmlVmaE ........................... 35 Eucalyptocrinus ........................................... 35 Callicrinus ............................................................ 39 Family BaTOCRIIVaE ............................. 4 Carpocrinus ........................................................... 42 Desmidocrim,s ............................. 43 Cflicocrin us ........... 43 lPeriechocrinus ................................. 44 çaccocrimt.s ...................................... 45 Aorocr[mts ........................................................... 47 Family PLaTVCRmaE ....................................................... 48 Lyonicrimts, new genus ....................................... .8 Myrtillocrinus ......... 9 Coccocr[mts ................................................................... Culicocrinus ............................................................. 5I Gemts and species indet., No. I ............................................... 5I Gemts and spec[es indct., No. 2 ................................ 51 Gemts and species indet., No. 3 ..................................... 52 Hapalocrinus ....................... 52 Brahmacrinus ............................................. 53 Nyctocrin us ........................................................................... 54 Marsipocrimts ........................................................................ 55 I!1 iv CONTEN TS PAGE 64 Order FLEXIBILIA ...................................... . ......... 64 Farnily LECAIOCRIIIDAE Lecanocrinus ................................................................ 65 .qnisocrinus ......................................................... 66 H ormocrinus ................ 66 Asaphocrinus ...................................... 67 Pycnosaccus ........................................................... 68 Family SAGENOCRINIDAE .. Sa9enocrinus ............ 68 Family ICHTHYOCRINIDAE .... Ichthyocrinus ....... 68 Clidochirus .............. Family TAXOCRIN'II)AE . 69 Protaxocrinus . 69 Gn orim ocrim«s ........... 70 Order INADUNATA ........ 7I LARVIFORMIA ...................................................................... Pisocrinus ....................................................... 72 Trîacrinus ...................................................................... 74 8 Zophocrinus .................................................................. 8 Tiaracrinus ................................ Mysticocrinus ........................................................... 83 Family HETEROCR1NIDAE ......................................................... 85 Myclodactylus ...................................................................... 85 Family CALCEOCRI NIDAE .................................................................... Morphology and evolutionary sequence ................................................... 88-o3 Analysis of Genera ......................................................... Cremacrim, s ...................................................................... IO5 Eucheirocrinus ................................................. Calceocrims ...................................   5 Halysiocrinus ........................................................ Family PETALOCRINIDAE ................................................................ 126 Pctalocrim«s .......................................................................... Crotalocrinus ...................................................................... 128 Family CYATHOCRIN'IDAE .............................................................. 131 Thalamocrinus ........................................................................ 3I Ampherisfocrim«s .................................................. 132 Lecythiocrinus ........................................................ 133 Cyathocrinus ........................................................ 133 Parisocrinus ........................................................ 135 Gissocrinus ......................................  35 Botryocrin,«s ........................................ I35 INSERTAE SEDIS ...................................... I37 Parastcphanocrinus .................................................... 139 Stcphanocrinus ................................................................ 139 BLASTOIDEA AND CYSTI]3EA ................... I4I Troostocrims ............................................................... I4 Tctracystis ......................................................................... 14 I Stribalocystites ............................ I42 Lysocystites ................................... 142 Caryocrhus ................................................................... 143 PERSONAL RECORD ................................................................ I44 BIBLIOGRAPHY OF AUTHOR'S V¢ORKS. I46 A. Sclcntific ................................................. .................. 146 I. In Collaboration .................................. .......................... I46 » I, Sole Authorship. I46 B. [isccllancous ......... IIx ............................... .................... EXPLANATION OF PLATES ........................... 16 7 ........................... 73 ANERICAN SILURIAN CRINOIDS tlY FRANK SPRINGER ASSOCIATE IN PALEONTOLOGY, U. S. NATIONAL _IUSEUII INTRODUCTION \Vestern Tennessee has been classic ground for American paleontologists ever since Gerard Troost, State Geologist of that state, brought to the I849 meet- ing of the American Association for the Advancement of Science a series of fossil crinoids collected by him in Decatur and neighboring counties, and sub- mitted through Professor Louis Agassiz 1 an imposing list of genera and species nev to science, of which he had prepared a monograph with full descriptions and numerous illustrations. For want of funds to defrav the expense, the mono- r  . graph was not published during the autho s lifetime, but remained buried until 9o9, when it was issued by the United States National Museum as Bulletin 65, the MS., together v«ith the collection, having been left bv Troost to tbe Smith- sonian Institution with a viev to publication. Er that time most of the new forms had been described by other authors, and the credit for the original dis- coveries announced in his list was lost to the one by whom it was so well deserved. In 1847 came the eminent German paleontologist, C. Ferdinand Roemer, who became deeply interested in the prolific fauna of the Tennessee Silurian, and during a sojourn of several weeks made extensive collections in Decatur County. The results of his researches were published in 186o in his well known monograph entitled " Die Silurische Fauna des \Vestlichen Tennessee:" 4to, Breslau, Germanv. Manv new species were brought out, and the work has been regarded as a standard for the area of which it treats. The Tenuessee .qrca The region under consideration lies along the Tennessee river and within its drainage. It abounds in natural exposures in the bluffs of the river and its tributaries, and in numerous glades where the fossiliferous limestone was ex- posed on the surface and disintegrated bv erosion of the softer overlying clays and marls. Fossils in great numbers were weathered out upon those glades, which produced the greater part of the specimens obtained bv the earlv collectors. Following the two pioneers above mentioned, Prof. J. M. Safford as State Geologist made extensive studies of the Silurian formations, and his accounts 1 Proc. Ara. Assn. Adv. Sci. (2), VIII, read Atg. 1849, vol. 2, I85O , pp. 59-64. ! 2 SMITHSONIAN INSTITUTION of the stratigraphy were published in the American Journal of Science for I86 I, and in his Rel' ort of t860.. Ile gave to the Niagaran, rocks the collective naine leniscus, which he subdivided int twc porti«,ns, a lower Ol- variegated bed, and an upper, or sponge-bearing led. I le also ruade important collections, which are n«w in the l[useum of Vanderl»ilt University at Nashville. In consequence of the pullication of the works of these early geologists, the Sihnian area became an attractive field fol collectors, and was visited ri-oto time to time by manv ardent fossil hunters, among them Col. Sidney S. I,yon, l'fol. ,\. I I. \Vorthel, of lllinois, ])r. Carl Rominger, of Michi.gan, Mrs. J. I. 3lilligan, who resided in Decalur Cotmtv fol a considcrable time, and lny old associate, Charles \Vachsmuth, who ruade two journeys along the Telmessee river durinR his sojourns in the South in the 'go's. He was greatly impressed with the richness of the fossil beds, and the opportunities which thev offered for intensive collecting, which the state of his health did hot permit him to utilize in that then rather wild country--although even with his lilnited facilities he lnade important acquisitic, ns. In more recent tilnes the geology of the western Tennessee region has been studied in detail bv Dr. -\ug. F. Foerste, whose vahmble pal»er on " Silurian and Devonian Lilnestones f \Vestern Tennessee" was pullished in 19o,3.' tle recog- nized in Safford's variegated beds the Clinton, Osgood, Laurel and \Valdron fiwmatins of the nrthern areas, and at the tp f this division two new foui-- mations, the Lego and 1 )ixn beds ; while to the upper or sponge-bearing bed of the lIeniscus he al»plied the new naine Brownsport. Still later investigations were ruade by Prof. \V. F. Pate, of Lebanon, Kentucky, and Dr. R. S. Bassler, of the United States National .hluaeuln. Their joint work pul)lished in I9o8 , entitled " The Late Xiagaran Strata of \Vest Tennessee," - contains the latest and fullest infornmti«m on the subject. It '`'`'as based upon several seasons of studv and collecting by llr. Pate, the last two of theln in mv service, supple- lnented by a careful review f the stratigl-al»hy by the two authors together in a field excursion ruade expressly fl" the lmrpose in I9o 7. Manv sections of typical lcalities are given, and the paper slmuld be consulted for a more detailed presentation f the facts than i. attempted here. Pate and Bassler fotlnd that the Brownsport and succeeding heds, which have furnished bv far the gl-eatel-part of the fossils from the glade region, are .eparal)le into four principal divisions, well marked faunallv and lith«logicallv fol- which thev pl-l),sed the forlnation lames Beech River, Bol», Lobelville and l)ecatur. The tabulation opposite of the several classifications as ruade bv them will be tlseful in tracing the horizons as mentioned in the works of different authors. 1 Journal of Geology, il, pp. 554-75. 2 Proc. U. S. Nat. Mus., vol. 34, PP. 407-43e. INTRODUCTION 3 The collections ruade by \Vachsnmth in the glades of Decatur County, and his observations on the mode of occurrence of the fossils, gave me a very strong ilnpression of the possibilities of that region for the paleontologist. In 9o5 I purchased the collection of l'rofessor ['ate, containing alnong other material considerable obtained bv hiln from the glades of Decatur and Perrv counties. From him I secured additional authentic information regarding the local condi- tions and prospects for further collecting, Oll the basis of which I arranged with Niagaran .çtrata of lVest Tcnnessce AFFORI3, I9. "Sponge-bearing bed Variegated bed Gant FOERSTE, I9o3. Brownsport PATE AND ]ASSLER, 19o8. Decatur  Coral zone Lobelville I.Bryozoan zone t Conchidium zone Bob Dyctyonella zolae 1. Uncinulus zone / Eucalyptocr. zoile Beech River Troostocr. zone _ Coccocr. zone Dixon Dixon Lego ] Lego Waldron Glenkirk \Valdron Laurel Laurel Osgood } Osgood Maddox Clinton Clinton him to make a systematic campaign in that area the follovcing season. Ail the crinoids that had been round up to that time had been in the form of specilnens weathered out upon the glades, and consisted lnainly of the loose calices with which the arms or finer structures were rarely preserved. If the beds from which they came could be located in place, there would be a possibility, in accordance with out long experience in the Burlington limestone, of finding some colonies with the cl-inoids imbedded in the lnatrix as originally deposited. Accordingly, [r. Pate, at the outset of his excursion in the summer of 9o6, xvas instructed to trace the crinoids by the fragments to their layer, and then dig. 4 SMITHSONIAN INSTITUTION The first result of this method was to locate along the bluffs of t3eech River in Decatur County an exposure of shales and shaly limestone some 60 feet in thickness, containing the beds from the erosîon of whîch the most productive Of the glades were derived. Preliminary tests showed that some layers of this contained crinoids in place in good preservation, and thereupon a force was organized for extensive quarrying, with proper blasting equipment, and the work of uncovering the fossiliferous layers was carrîed on for the remainder of the summer under Mr. Pate's energetic direction. It was resumed the follow- ing summer, during which by persistent quarrying and blasting the favorable exposures were thoroughly excavated, and the accessible crinoid-bearîng strata exhausted. These were chiefly in the upper shales, now known as the Euca,pto- crizus zone. Some smaller exposures in the vicinity produced the name-giving genera of the Troostocriu,s a:d Coccocrbms zones. Several vears later Fred- erick Braun was sent for a final inspection of the Tennessee river area, especially the weathered quarry dumps, which yielded some excellent additional specimens. The occurrence of the crinoids as disclosed by these quarrying operations was rather irregular, and much material was moved that proved tobe barren. But in the aggreate the work of the two seasons was eminently successful, yielding a total of ninety-five species of crinoids, of which fifty-nine were new, distributed among thirty-three genera, besides a blastoid and a few cvstids. The crinoids from the shales were usually silicified, and for the most part in excellent preservation. The matrix was readily removed by preparation, so that manv of them when ready for study lmd the crown freely exposed on one or ail sides. In some cases considerable colonies were round; for example, the hitherto rare "" Coccocri,us" bacca, of which about a thousand calices were recovered from a bed of shaly limestone of limited area. Taking the collection as a whole, it mav be said without exaggeration that more finely preserved crinoids were secured b Mr. Pate's two summers' campaign than had been round by all the collectors in the Tennessee Silurian during the sixty years preceding. Many rare forms, hitherto known onlv fronl isolated or fragmentary speci- mens, occurred in numbers sufficient for a thorough elucidation of their charac- ters, and an even greater number were entirelv new. This xvas conspicuouslv true for the Flexibilia, the Clceocrinidae and several genera of Cmerata, o'f which there were forms and specimens such as had never been seen before. Details of these, however, will be better shown bv the figures upon the plates. Upon the broader question of the parallelism of the crinoidal fauna with that of the north European Silurian, the collection furnishes a wealth 15f infor- mation confirmatory of the existence of a migrational connection between the two areas. In several rare and specialized genera, as well as in some of abundant occurrence, species are round which except for difference in matrix can scarcelv be distiuguished from the English or Swedish forms. The general racles of the fauna proclaims a close relationsbip, and this impression is reinforced bv the silnilaritv of manv of the other fossils. INTRODUCTION 5 The prominent exposures thus worked belong to the Beech River forlna- tion of the Brownsport group as designated by Pate and Bassler in their paper already inentioned, which they furthersubdivided into three zones called in ascending order Coccocrin us zone, Troostocrin us zone and Eucalyptocrinus zone. Of these the last, or upper, zone was by far the most important, the greater part of the crinoids having corne front it. The other two are chieflv characterized Ge,eral Section Tennessee, etc. Niagaran Devonian Helderbergian TENNESSEE Linden Decatur limest. Lobelville, coral zone Bob, limest, and shale Eucalyptocrinus zone, shale Troostocrinus zone, shale and limest. Coccocrinus zone, shaly limest. Dixon, shale and red limest. Lego. limest. \Valdron, shale Laurel, massive limest. Osgood, shale and limest. OTHER AREAS Louisville ls. Kentucky, Ind. d Cedarville dol Ohio Racine dol. Illinois Hopkinton dol. Ioxva Indiana Indiana Rochester shale New York I EUROPE by the forms from which their llalnes are given. Al»ove the shales is a consider- able thickness of the Decatur lilnestone, which yielded only a few specimens here, but at a locality along the bluffs of the Telmessee river some remarkably distinct forms were obtained. At other places in the immediate vicinity the lower Niagaran formations occur, from Osgood to Dixon, so that the p.rincipal mena- bers are represented in their proper sequence within a short distance. To facilitate reference to the horizons mentioned in the descriptions, I give above the general section of the Silurian forlnations of Tennessee as deter- mined by Pate and Bassler, together with the equivalents which mav etater into tbe discussions. 6 SMITHSONIAN 1NSTITUTIç)N TIe Izdiaa .4'ca Next to Temlessee tlle most imlmrtant western Silurian area is in ]ndiana. which is the typical region f,-r the three lwer Niagaran formations. The first important devdopment there was matie by James Hall ad under his direction at XValdron, in the shale beds which bear its naine. Among a wealth of other fossis these produced a remarkable crinoidal fauna, containig numerous nexv forms which were described bv I lall in several publications from 869 to 882. Underlyin K the XValdron, at the town of St. Paul in the saine vicinitv, is an immese exposure of the Laurel formation, a massive limestone of considerable thickness, which bas vielded a crinoid fauna c,f a racles markedly different from those of the other Silurian members. An excellent collection from this area was ruade bv the 1)octors t-Imvard, which was acquired bv the Geological Survey of 1ndiana and formed the basis of descriptions bv S. A. Miller in the  7th and gth Annual Reports. Dr. C. C. XVashlmrn also ruade an extensive collection from which a ch,,ice selection of crinoids passed into my hands, the main collection leing afterwards acquired bv the Universitv of Chicavo. G,o(l crinoid material was ,l)tained at St. Paul, as well as in the XVabash area to the north and the Osgood beds to the south, bv A. C Benedict, and in the XValdron shale at Harts- ville lv Dr. 5Ioses Elrod, both of which were subsequeltly acquired bv me, as was also the large collection of 5If. John F. Hammell, of Madison, Indiana, which contained important material from ail these formations. The northern area of XVabash, Grant and ç[adiscm coumies presents differ- ences in the crinoid content from the l.aurel which suKgest a connection, in part at least, with the Racine dol«mite of the Çhicago area. The most characteristic species of the St. Paul rocks are hot round there, although some of the northern species are thoug-ht to occur at St. Paul. The geologT of the lndiana Niagaran bas been carefully studied bv Dr. Foerste, and his papers on the subject will be round fully instructive. ' Being reatly impressed with the possibilities of the St. Paul expasures of the I.aurel f«wmation, and the strikinK character of its fauna as indicated by tle earlier collections, I ruade some special eorts from rime to rime to secure a more complete representation of its c,ntents. The crinoids were chieflv con- tained in the softer interbedded lavers between the beds of lnassive limestone which were extensivelv quarried f,u- comme-cial purposes. These layers consti- tuted the débris of the quarries left in scattered dumps, in which the specimens became exposed b) weatherin from vear to year, affordin the main resource of the collectors. No prolific colonies were uncovere(l, and no great quantity of specimens was observed, but tle l)reservation was excellent, and new or rare forms were ahvavs to be expected. Crefnl overhauling of this materiaI was ruade tmder mv direction during several vears by Carles S. Beachler in 1887,  eist Ann. Rep. Dep. Geol. Indiana, I8, pp. 213- ; 22d ibid., 897 , pp. I9S_28S. I NTRODUCTION 7 Frederick 1-',raun in I)I l, and, most ilnportant of all, duri11p_, the three seasons of t0tS, 9 6, aud 97 bv lnV forluer assistant, the late l )r. I lerrick E. Wilson, who had befcwe that ruade some collections there fl- the Universitv of Chicago. Local cç, nditic,11s wele favorable during his calupaigns, which xvel-e fairly suc- cessful, and aln,n,el his acquisitions were some of the ilnl)«wtant types described in this work. The New ]'ork /lrca In the eastern Silurian area the classic localitv is I,ockpol-t, New York. Extensive exposures of the Rochester shale vielded a 1-ich and varied fauna, aluon which were luany new forlns of crinc, ids which forlned the ty'pes of .enera and species descl-ibed bv Hall in the earlier volumes of the Paleontolo.y of New York. The pioneer collections lnade lv Professor Hall and Colonel Jewett ultimatelv passed into the possession of the Alnericala Iuseunl of Natural Nistorv at Ne v Vork, and the State 5Iuseuln at Albanv, where I have been afforded abundalt opportunity for their study, as well as the types c,f Hall's lmmel-ous species from \Valdl-ol. Another fine collection fl-om the saine fol-ma- tion at Grimsl)y, Qntario, vas assembled bv the elninent financier, the late Sir Edluund \Valker, which was also placed at mv disposal, and is now in the Univelsitv of Toronto. The most intilnate and protracted studv of the Lockport beds, shales and ulMerlying lilnestones, was ruade lv the resident lfllysician, f)r. E. N. S. Rinue- ber,. Durin, a residence of m(re than thirtv vears he accumulated a large col- lection which formed the basis of several important publicatiolS bv him ff-oto 882 to 89o, in which a nulnler of new enera and species were described.  The crinoids and cvstids, ilcludin the types of Rin-uebel--'s species, were acquired bv me, and form an ilnportant part of the luaterial studied. In additiou to this, ] bave the fruits of three Calupaigns in the vears 9o, 9  2 and 9  4 at Lockport bv the veteran collector, Frederick P,l-aUl, in mv service. Ill the course of an intensive studv of the shales he carried on lar,-e quarryin,e, operations where the conditions were round favorable. Some of his acquisitions vel-e of the p41-eatest importance, notablv alnong the Flexihilia and the al»errant genus z][yclodactyhts, as fullv described in mv monogl-alh of the former ,q-roup of 02o, and in the paper on Unusual 13"OrlnS of Fossil Cl-inoids, of 926. While the I.ockpol-t fauna does hot fall strictly within the lilnits of this Wol-k, SOlne COllsideration of it is essential fc, r purposes of COlnparisola, as the formation is to be correlated with the Osgood of the Iidiana area.  Tvo New Species of Crinoids from Shale of the Niauara Group. Jour. Cin. Soc. Nat. Hist.. Oct., x882, p- I9: New Fossils from the Niagara Period, Proc. Acad. Nat. Sci. Phil., 884, p. 44; Nev Genera and Species of Fossils from the Niagara Shales, Bull. Buff. Soc. Nat. Sci., x886, p. 5; Some New Species of Fossils from the Niagara Shales, Proc. Acad. Nat. Sci. Phil., 888, p. x3 ; The Niagara Shales of Western New York, Ara. Geol., May, x888, p. -63: The Calceocrinidae: A Revision of the Family, and Description of New Species, Anu. New York Acad. Sci., 889, p. 388 The Crinoidea of the Lover Niagara Limestone at Lockport, Ann. N. Y..Acad. Sci., July, 89o, p. 30. tq SMITIISONIAN INSTITUTION Th e CI[ica9o .ŒE rca Another important Silurian area to be considered by wav of comparison is that of the Racine dolomite at Chicago, which has produced a considerable crinoidal fauna, heretofore fully worked up and described by Stuart \Veller 1 and A. \V. Slocom." In this formation the calcareous test of the crinoids has been largely dissolved bv chemical action, so that for the most part only the inter- nal casts are preserved. For this reason close comparison of characters is usna]]v difficult. Dut the general racles of the fauna is very important, differing in manv respects from those of southern Indiana and Tennessee, and paral]eling that of the European Silurian in the presence of the highly specialized genus Crotalo- crius. In this it is reinforced by the occurrence in the equivalent Hopkinton dolomite of Iowa of the equally specialized Petalocrinus, also of Gotland. The Foreig Siluria In view of the close parallelism between the Alnerican Silurian and that of northern Europe before alluded to, it becalne desirable to secure an adequate representation of the crinoids froln the two principal localities, Dudlev in En- land, and the island of Gotland, Sweden. I had the advantage during a sojourn in Europe in I887 of personal examination and studv of the p_,reat Silurian col- lections in the British ][useuln, and in the Dudlev Museum, and also of several private collections at Dudley during a visit to that field, especially tho.e of Mr. Charles Holcroft, now in tbe Birmingham [useuln, Of Mr. John Gray, since acquired bv the British Museum, and of Mr. \Villiam Madely. Through the good offices of l[essrs. Holcroft and lIadely, and from other local collectors, I was able to secure considerable useful material from that ramons locality, which has been increased by purchases and exchanges since. From Gotland the more common species were obtained from time to time from dealers, and rarer ones from the Riks ]Iuseuln at Stockholm by exchange, thanks to the liberalitv of mv good friend Prof. G. Lindstr/Sm. In more recent years I secured the ser- vices of local collectors on the island, first of Prof. G. Klinteberg, and after- wards of Mr. A. Florin, an experienced collector, who l,:l-lew the geology of the island thoroughly, whom I engaged for a season's operations with blasting equip- ment. This resulted in SOllle valuahle acquisitions in the way of rare, and even new, forms, which have aided materiallv in the comparative studv of the faunas. All of the material thus accumulated forms part of mv personal collection iii the United States National l[useum, where it will remain in perpetuity. The total number of species herein illustrated and discussed is 98 helong- ing to 63 genera; of these 74 species are new and I2 undetermined. Thev are distributed as follows" Camerata, total lO 3, new 43, undetermined 12; Flexi- bilia, total 18, new 3 : Inadulaata, total 77, new 28.  Bull. Chicago Acad. Sci., 4, pt. , 9oo. - Field Columbian Museum, 2, Geol. Ser., No. o, 9o8 INTRODUCTION 9 01-icait oj  the lVork The idea of a systematic work upon the American Silurian crinoids was first suggested by the account of the wonderful crinoidal fauna of Gotland by Angelin in lais Iconographia Crinoideorum, and afterward by Bather in tbe Cri- noidea of Gotland, and by my observations upon lae 1Znglish collections from the Dudley area al»ove mertioned. The collections made bv Wachsmuth in Ten- nessee and Beachler in Indiana indicated a certain correspondence between the Silurian crinoidal faunas of the two continents which offered an inviting subject for investigation, and it was probably this consideration which induced the be- ginning of efforts toward the assembling of material with reference toit. It was hot until the discovery of the rich collections ruade bv Pate in 9o6- 7 that the plans took definite shape with the starting of drawings bv .Ir. Chapman, con- current with the work upon the Flexibilia. These were prosecuted froln time to time in a desultory way, as the demands of business and of other work permitted, and were continued as additional material was acquired. Preliminary studies and notes xvere ruade in the saine irregular war, but it was only in I923 that I round myself in a position to assemble the drawings, and begin the final prepa- ration of the text. At this point the work was suspended bv a protracted physical breakdown incident to an impaired heart, from which a slow recovery has enabled me to resume it at intervals. That I have been able to bring the work to a conclusion is a result that was hot expected : and for which I ara profoundly thankful. In conformitv with the preparatory field-work, this treatise is chiefly limited to the Silurian faunas of Tennessee and Indiana. The crinoids of the Lockport field have been thoroughly treated bv Hall and Ringueberg. and a few of them .q , since by myself. \Veller's and locom s works upon the Çhicago crinoids cover that field exhaustivelv. Therefore. except for incidental reference to a few forms for special reasons, it bas hot been deemed necessarv to include those of either field. For a similar reason I ana omitting most of tbe \Valdron species, which were so fullv described by Hall. The effort is ruade to reduce the treatment of species to a simple presenta- tion of the essential facts, avoidin.o, so far as possible the formal recital of char- acters which often becomes irksome. In some in.tances, where a form or group bas been the subject of extended discussion hitherto, or where the acquisition of new material has thrown important light upon forms or questions before obscure, full latitude is employed. This will account for some differences in method that ma3, be noticeable. In the descriptions it has hot been thought necessary to include tables of dimensions. They are usuallv only a pedantic incumbrance, inasmuch as the saine information is more conveniently furnished bv the drawings, which are IO SMITHSONIAN INSTITUTION alwavs ruade to scale upon a photograplic basis, and are of natural size except as indicated in the legend. kVhile the chier purpose of this treatise is to brin K to light the nexv Kenera and species which have been discovered within the areas hereinbefore indicated, it is also boped to increase our knowle(1Ke of forms l)revi.usly known where nexv information ha been Kained by later discoveries. But where such species have already l»een adequately illustrated and dcscribed, thev will hot 1)e included here. As to synonymy, Dr. assler's Bibliogral)hic Index of Ordovician and Silurian Fossils, pullished bv lhe Uni/ed States National 5[useum as Hulletin 94, in o5, brinKs references to ail esseutial literature relative to Alnerican genera and species down to that date in the Kreatest detail and most convell{ent form. The publicatim has beeu widely distributed, and is available in everv scieutific lil)rarv and in the hands of ail working 1)aleontoloR-ists. It is therefore unneces- sarv to encuml)er these paKes wiIh the usual full citations of authors previ(.us ta that date, inasmuch as a simple vcference tc that work will afford all the needful information. I ara thus at libertv to Iimit mv references coveriu K dates previous t 05 to such of the treatises as may for the sake )f claritv or convenience be deemed of special importance iu the historv of the fc)rm under consideration. Iu the notation of Horizon and Localitv in connection with species,  ara avoiding the needless repetition of tbe terre '" Silurian," inasmuch as all species herein descrilmd, unless otherwise stated, are from that horizon, and reference to the respective formations is usuallv quite suflcient t identifv the Keoloical position. The material upon which this work is based is derived from the folIowing sources, consistin K «f collectims either ruade fw, or acquired by, myself, and uow in the United States National 5Iuseuln, and those lelonvin K to other own- crs which I bave been privileged to studv: . luthot"s Collcctimzs Uscd Rocms'rwR SHaLE : Lokporl, New York Bv Frederick Braun, Igio, I, I9 4. From Dr. E. collection, Lockport. N. S. Ringueberg, Oscoor, I.AtRL AND \VaLDRON ; Indiana and Te:messee P,v Charles S. I3eachler, 8,qî; St. Paul and \Valdron. P, raun, I)I- at St. Paul. assler and Bl-atm, at Newsom, Teunessee. Herrick E. \Vilson, i95, 1916, 917; St. l?aul. ]ndiana. From Dr. Moses Elrod, collection- Hartsville, ]ndiana. Dr. C. C. \Vash- lmrn" \Valdr,m, lndiana. [r. John F. Hammell, collection- [adison, Indiana, includilg-that of A. C lqenedîct- St. Paul and other southern localities and northern area. INTRODUCTION I..vr Na(;aR^N (BROWNSI'ORT) ; Tennessee Bv Charles \Vachsnmth, ,q85 to 888. \V. F. Pate, I9O6 , 9o7 . Braun, From Col. S. S. Lyon, collection, 85 ) to 86o. 5Ifs. J. M. 5Iilligan, collec- tion ; Jacksonville, Illinois. Pate, collectiou; before 9o6. OTHER COLI.ECTIONS STUDIED Alnericall 5[useuIn Natural H istory, Xew York, Hall Collection ; Lockport. State Museum, New York, Albany, t]all and Jewett collections; Lockport and Valdron. Sir Edmund Valker, Toranto; Grimsby, Ontario. Valker Museum. Universitv of Chicago ; Çhicago area and St. Paul. Unix ersitv of lllinois, Cham- paign: Vorthen collectim. Vauderbilt University, Nashville; Safford collec- tiou. United States National Museum: Çontaining Troost collection, Termes- sec; Rominger collecticn, Tennessee and 5Iichigan: [r. Ulrich's collection of Ordovician from [ilmesota. British 5[useuln ; London. Dudlev Museum ; Dudlev. England. All of these last mentioned collections were most generously placed at mv disposal or studv, for which I aih deeply indebted to the owuers and authorities in charge of them. I ara also under renewed obligation to I lon. Charles D. XValcott, Secretarv of the Smithsonian Iustitution : to Dr. Geo. P. Merrill, head of the Divisiou of Geology in the National 5Iuseum, for their continued interest in mv researches : to Dr. R. S. Bassler, Curator of Paleontology, for his unflaggin assistance durin K their prosecution: aud fa 5Iiss 5largaret XV. Moodey, Registrar in the Division of Geology, wh, has direct charge of mv collection and library, and has adlniuistered mv «»Nce in the Xatimal 5Iuseum durin K my protracted dis- abilitv, when I was endeavoring to Calnplete the later stages of this work through the medium of correspondence. This invlved llUlneraus COlmnissions in the wav of selecting and sending specimeus, looks and notes, looking up references, and attendiug to the endless details incideut to such investigalions..kll of these were executed bv her, uuder advice of Dr. Bassler when needed, with a zeal and iutelligent interest that met, and often anticipated, everv requirement. The drawings for the plates have been in the course of execution during a peri)d of more than fifteen years, bv [r. Kenneth M. Chapman, of Santa Fé, Xew [exico, the artist of manv of mv former works. Thev are based upon 1)hotographs ruade bv himself at first, and in the later stages bv Dr. Bassler and Dr. C. E. Resser. To his keen observation I owe their accuracv of details, and as works of art the drawings speak for themselves. Except as otherwise stated, the originals of all the drawings, including the types of the nexv species herein described, are in the author's collection in the United States National Iuseum. I2 SMITHSONIAN INSTITUTION Order CAMERATA Wachsmuth and Springer CRINOIDEA IN WHICH TI[E LOWER BRACHIALS TAKE PART IN TIlE DORSAL CUP. ALL PLATES OF CALYX UNITED BY CLOSE SUTURE AND IMMOVABLE. ]V[OUT/-I AND FOOD-GROOVES COMPLETELY COVERED, THE COVERING PIECES OF THE LATTER FREQUENTLY INCORPORATED IN THE TEG- MEN..NAL OPENING EXCENTRIC OF SUBCENTR-AL, FRE_OUENTLY AT THE END OF A TUBE. ARMS UNISERIAL OR B[SERI_AL, AND PINNULATE. The crinoids of this order constitute more than hall of those hereln treated, embracing 31 genera of which 7 are new, and 43 new species out of a total of Io 3. Important new light is shed upon some forms heretofore hot xvell understood such as Gaacrinus, Laniterocrim«s and Lyonicrinus. The most prolific of the genera is Marsipocrim«s, hitherto accounted rare, which now appears from the Tennessee area to the number of Io species, some of tbem in a preservation and with a wealth of individuals belote unknown. Family DIMEROCRINIDAE Bather This falnily, embracing substantiallv all dicyclic Camerata with truncate 9ost. B in which the RR are in contact except at the anal side, while it has an extreme range from Ordovician to Devonian, is essentially a Silurian form, of which w4 have four well marked genera in the present collection. DIMEROCRINUS Phillips Plate « Dim.erocrin.i¢«s Phillips in Murchison's Sil. Syst., I839, p. 674. Dinerocrinus D'Orbigny, Prodr. Pal., , 85o, p. 46.Vachsmuth and Springer, ev. Pal., 2, I88I, pp. 97.--Bather, Treatise on Zool. (Lankester), 3, 9oo, p. 98.--Zittel-Eastman, Textb. Pal., d Ed., 93, P. 87.Jaekel, Phylogenie und System, 98, p. 4L--Bassler, Bibliogr. Index, Bull. 92, U. S. Nat. Mus., 95, P. 438. Thysanocrims Hall, Pal. New York, 2, 852, pp. 88, 355.--'0,rachsmuth and Springer, N. A. Cin. Cam., 897, p. 9o. Glypa«ter Hall, Pal. New York, 2, I852, p. I87; 28th Rep. New York St. l{us., I879, p. I3L--\Vachsmuth and Springer, Rev. Pal., 2, 88i, p. I93. Eucrinus Angelin, in part, Icon. Crin. Suecc., 878, p. 98. Calvx rather elongate : IBB 5 ; post. B truncate ; first anal plate in line with RR, followed by 3 in second range ; iBr in several ranges : anus without a tube ; arms biserial, simple, 2 or 4 to the ray, directed upwards; cohmm round. Gcnotyie. Dimerocrimts dccadactyh¢s Phillips. Distribution.. Silurian; England, Gotland, America. This genus is xvell represented in the English Silurian under Phillips' type from Dudley, in Gotland by several species under the naine Eucrinus, and in America bv a series of species under Thysanocrin-us and G,plaste; to which nmst now be added importnt new forms from the Tennessee collections. In the monogrvph of Crinoidea Camerata of 897 priority was given to the naine Thysanocrinus, a course which has since been modified in fayot of the per- fectlv recognizable type described bv Phil]ips. D[ MEROCRI N1DAE 13 Dimerocrinus planus nexv species Plate r., figs. -7 A finely preserved species, with elongate conical calyx, smooth surface, and verv stout arms . to the ray; the interl»rachial svstem is well developed in sev- eral ranges, 1) 3- which the brachials are incorporated to the third or fourth IIBr. IBB Slnall, rarely visible from a side view. Anus directlv through the tegmen. Çolunm long, composed of uniformly short columnals, averaging about ._2, nana. This is a conspicuous fossil in the Tennessee Silurian, of which besides the seven speci- mens figured there are a nulnber of others showing similar characters. In having only ten arms it is closer to the Dudley species than to those from Gotland. Horicon aud locality. Beech River formation, Brownsport group, Niagaran; Decatur Çounty, Tennessee. As collections are ruade, it is not always possible to give the subdivision from which the species is derived. For the P, eech River formation, by far the greater part of the specimens are from the upper, Eucalyptocrimts, zone. Dimerocrinus milliganae (Miller aud Gurley) Plate _r, fig. 8 Glyptastcr milliganae Millet and Gurley, Bull. m, Illinois St. Mus., 896, p. 87, pl. 5, figs. 7-9. I am figuring the type of this Tennessee species, formerlv in the collection af Mrs..I.M. Milligan. Only the calvx is preserved, but it is well differentiated by the prominent ridges along the basal and radial series, more angular contour generally, and larger IBB. Horizon and local#y, saine as last. Dimerocrinus nodobasis new species Platc z. figs. 9, zo Similar to D. planus but differing in the presence of sharp angular cusps upon the basals; the IBB are extremelv small, entirely concealed bv tle top columnal. Horizon and locality, saine as last. Dimerocrinus inornatus (Hall) Plate z. figs. zr, ze Gl3'ptastcr inornalus Hall, Trans. Aih. Inst., 4, 863, p. o5; 28th Rep. New York St. Mus., x879, p. 34, pl. x4, figs. x-6.--Bassler, Bibliogr. Index, x95, P. 439. A massive species with strongly nodose basals, producing a stellate base. Flom the Waldron formation, Hartsville, Indiana. D. (Glyptaster) occidcntalis (Hall). 28th Rep. New York St. 3[us., I8î9, p. 33, pl. 13, figs. 7-ri, a much more delicate species with sharp surface sculpturing, is from the saine formation at \Valdron. 14 SMITHSONIAN INSTITUTION To the foregoing Anlerican species may be added Rhodocrinus halli Lyon, from the Louisville limestone, a doubtful species from the XValdron, three species fronl the Racine dolomite, rive from the Rochester shale, and one from the Helderbergian--atl as listed in Bassler's bibliography. The follmving rive species of Angelin from Gotland, Eucrimts intcrmdialis, ornatus, hwvis, quinqanc, qula.ris and spcciosus, with 4 arms to the ray, are referred to this genus, alld probably two or more of them are synonyms. Eudimerocrinus multibrachiatus new genus and species Plate z, ficjs. .r 3, z3a. b, z 4 The difference in arnl structure between this and all species referred to Dimerocriuus is so great that to be consistent with the practice follovced in other cases, it seems imperative to propose a new genus for its receptinn. \Vhile in those forms the arms are alxvays simple, hot branching beyond the calyx, here they undergo several bifurcations at wide angles up to as manv as three, giving 6 or 8 final branches. These are all stout, and biserial both above and below the bifurcationsa type of arm highly distinctive of several enel-a. such as .4bacocriuus, Clonocrius, Mcgistocrinus. etc. In the COlnpositiorl of the calyx there is no difference, and with specimens consisting of the calvx alol]e it would be impossible to point out anv character for distinction more than specific. But we have two unusuallv fille specimens, with the arnls ahnost completely pre- served to the numerous bifurcations, and both entirelv freed from the matrix, so that the characters of the calyx are fully disclosed ou ail sides. The surface structure is remarkabh" clear and distinct, with Stl-ong sculpturing, many of the plates sharply projecting and ahnost spinose. If in this species the interbrachials extended down to a connection with the basals, it might fairly go with Eucrimts vemtstus and E. udnor of Angelin, for which \Vachsmuth and Springer established the genus Anthcmocrimts  under the Rhodocrinidae. Horizon and locality. Beech River formation, Brownsport group, Niagaran; Decatur Çounty, Tennessee. CYPHOCRINUS S. A. Miller Plate I Cphocrhms MiIler, I8th Ann. Rep. Dep. Geol. Indiana, 1894, p..3o4 (adv. sheets 1892).Bather, Treatise on Zool., 3, 19oo, p. I99.--WeIIer, BuIl. Chicago Acad. Sci., 4, pt. 1, p. 75 (synonymy discussed).-- Zittel-Eastman, Textb. Pal., 2d Ed., 1913, p. I87.--Bassler, Bibliogr. Index, 1915, p. 34o. Iqyptiocrinus Wachsmuth and Springer, Ara. Geol., IO, I892, p. I38; N./. Crin. Caln., 1897, p. 200. Clyx constructed as in Dimerocrinus, but low, wide, and recurving from a narrow obconical base to a spreadin, inverted bowl, with arms directed down- wards; axillary and ceutral teganen plates spiniferous. Genotype. Cyphocrimts 9orbyi S. A. Miller. Distribution. Silurian; hot known outside of America. 1 Rev. Pal., 2, 1881, p. 208. See also Jaekel, Phylogenie tuld System, 1918, p. 4o, where he claims that E. minor may have only 4 IBB. DI M EROCRI NI DAE 1 5 Cyphocrinus gorbyi S. A. Miller Plate _r. figs. r5-z8 Cyphocrinus 9orbyi Miller, I8th Ann. Rep. Indiana Dep. Geol., 1894 (adv. sheets, 1892, p. 5I), p. 305, pl. 7, figs. 14-I6.--Hyptiocrim«s typus \Vachsmuth and Springer, Am. Geol., IO, 1892, p. 138; N. A. Crin. Cam., I897, p. 2Ol, pl. I9, figs. 6 a-c. This genus, while contrasting in the hemisl)heric and dl-ooping contour widely with the preceding, clearly exhibits the essential characters of the falnilv in the construction of the calyx. The arlns have hot been round beyond slight remnants, from which it is evident that thev were biserial, stout and unbranched" and from the appearance of the extremelv elongate spilaous anabulacrals upon the tegmen SUlmOUlting the rays, and the direction of the arm-openilagS, it might be inferred that thev were of the reculalbent type, with the pinlmles directed outward. Four specimens of the type species, which is quite abundant at the type locality, are figured in order to show some details mooe fullv than appeared in the original description. This applies especially to the interbrachial openings at the margin of the tegmen for fixed Ifinnules to the number of 4 or 6 between the ravs and their divisions. These openings, formerly interpreted as " respiratory pores," are now traced in several Camerate genera with unbranched arms to a connection with the arm-groove? \Veller has described a species, C chicagoensis, from the Racine dolomite of the Chicago area, but otherwise the form bas only been round in the Laurel limestone at St. Paul, Indiana. This and the next following f«,rm were independently described by Wachsmuth and Springer and S. A..Iiller in 892. The \Vachsmuth and Springer names xvere published in the American Geologist for September, 8c2, but owing to some delay in printing, that number of the magazine was not actuallv issued until some weeks after its purported date. [eantime Ir. Miller issued advance sheets of the Sth Rep. Geol. Indiana containing his new names, which were specially distributed to his correspondents. The claire was ruade that this distribution antedated the delivery of the magazine to its subscribers. Dr. \Veller in con- nection with lais Chicago species considered the question in the light of such evidence as could be obtained, and decided in fayot of the priority of liller's names, which I bave accepted. Horizon and Iocalitv. Laurel limestone. St. Paul, Indiana. GAZACRINUS S. A. 5Iiller Plate 2 Gaacrimts Miller, ISth Rep. Geol. Dep. Indiana, I894, p. 3o3 (adv. sheets, I892, p. 49), N. A. Geol. Pal., ISt App., I892, p. 679: ibid., 2d App., I894, p. 746.--Weller, t3ull. Chicago Acad. Sci., 4. pt. I, I9OO, p. 78, fig. 38 (synonymy discussed).--Bather, Treatise on Zool., 3, 9co, p. I88, fig. Ii9.---Zittel- Eastman, Textb. Pal., _'2d Ed. I913, p. i87.--Jaekel, lhylogenie und System, I918, pp. 4t, 8o.--Bassler, Bibliogr. Index, I915, p. 545. Idiocrinus Wachsmuth and Springer, Ara. Geol., IO, I892, p. 35; N. A. Crin. Cana., I897, p. 2o2. Base concave, ]Y',, confined to the caxrity; i]3r in cup limited to a single large plate in each interradiu. COlmecting with tegaalen, that of posterior side followinff the truncate B : arrllS biserial, simple, directed upwards. =k_nUS without a tube. Teaaen composed of a few plates, crowned with a central pyramid.  See Springer, Scyphocrim«s, Smithsonian Inst., I97, pp. 33-37- I6 SM1TIISONIAN INSTITUTION Gcnotype. Gacacrim«s inornatus S. A. Miller. Distribution. Silurian to Devonian; America. Not recognized in the foreign Silurian. The position and relations of this genus have been misunderstood. Bather placed it anmng the Flexibilia. Jaekel in his latest attempt at the systematic arrangement of the crinoids, Philogenie und System, I918, does hot fully agree with this reference, but in order to be on the sale side places it in each of lais two most widely distinct grand divisions ; first under his subclass Cladocrinoidea, equivalent to the Camerata, in a familv next to the Dimerocrinidae (p. 4I), and then in lais other subclass, Pentacrinoidea (p. 8o), in a family Gazacrinidae under the suborder Calpiocrinitesan association of types about as illcongruous as could possibly be imagined. As originally described, partly through errors of definition and partly through limita- tion of material, the essential characters of the genus were hOt fully di.closed, it belng known only bv two species from a single locality, specinlens of which were rare and imperfect. Later acquisitions have furnished much nmv information, giving us now a series of seveu or more species ranging through several formations of the Silurian in different localities and up into the Devonian. These bave added greatly to our knowledge of strtctures unsuspected before. From them it nmv appears tlmt the enus has ten heavy, biserial arms, directed upward and closely abutting. The tegmen is unlike tbat of others of the family, and is a distinct variation from that of the Camerata generally, being composed of a fmv large interambula- cral plates, surnmmated by a set of triangular interlocking plates thought to be orals which vary in different species, being suturallv closed or even anchylosed iu some to form a solid pyramid with angular vertical ridges forming grooves into which the arms may fit. The various forms of this structure are well shown on plate 2, aud from these it mav be seen that there is a strong analogy between this tegmen and that of the Calyptocrinidae, as will appear by comparison with the figures of Eu«alyptocrinus crassus Oll plate 7, figs. i 9, o. This will furnish the desired line of connection with the Camerate type. See also \Vachsmnth and Springer, N. A. Crin. Cm., I897, pl. 8I. fiZs, z2-I5 alad Hall 28tla Rep. Nev York St. Mus., I879, pl. 9, figs. I, 3, 4, 5- The interpretation of the pyramid of plates that we call orals is involved in considerable doubt. They are buried under closely fitting arms, which xvould affect the reflarity of their development, and there is manifest in some species a strong tendency to fusion, by which the relation of the component plates may bc greatly modified. The definition of the genus bv Ir. Miller, and description of the type species, are erro- neous as to the composition of the base in the definite statement that it has " no subradials " that is, that it is a monocvclic criuoid, which is a serious and fundamental error. This was due to loose observation, and the lack of careful preparation of the specimens to bring out the infrabasals at the bottom of the cavity, where they are plainly to be seen in more than a dozen of my specimens. \Vachsnmth and Springer's definition of ldiocrinus, based on the saine species as Miller's under a different naine, specified the 5 small IBB at the bottom of the cavity, and the fact is shown by numerous examples of this and other species. It is also stated by Millet that the arms are composed of fi single series of flattened plates, which was pure guess-work, and contrarv to the fact as now known. Gazacrinus inornatus S. A. 3[iller Plate 2, figs. r_-O Gazacrinus inornatus Miller, Sth Rep. Indiana Dep. Geol., I894 (adv. sheets, 892, p. 49), P. 3o3, pl. 5, figs. 9, m, 5-7.---ldiocrinus elon9atus ,Vachsmuth and Springer, Ara. Geol., xo, 892, p. I36- N. A. Crin. Cam., I897, p. 2o3, pl. I8, figs. 8 a-c. ' Specilnens slnall, average height to width at top of iBr 12 X I I 111111. Clvx elonffate conical. Base narrow with 1313 higher than wide, curving abruptly into DIMEROCRINIDAE 17 a cavity forlning an iuverted cone with the small IBB at the bottom. RR very large, iBr and IIBr projectiug over into the teg-mel, lmt exteriorlv the brachials pass illseusiblv into the large biserial arlns, two to the rav, wbich abut closely both between the ravs and tbeir divisious. \rentral pyralnid somewhat variable ill sbape, asymlnetric, consistiug of rive similar plates x ith a sulaller central one interposed" or tbe central plate lnay represent the posterior oral pusbed in be- tweeu the others by aual structures, with the posterior triangular plate flauked bv two others connecting folming the border of the anal opeuiug. These pyramid plates abut by their proximal edges upon the bent over processes formed by ex- teusions of the IIBr and iBr plates. Surface Slnooth. Horizon and localily. Laurel limestone, Niagaran ; St. Paul, Indiana. Gazacrlnus magnus nexv species Plate 2, figs. IO, II, 12 This species, from the sarne horizou and locality as the preceding, is known oulv from the teRlniual pyramid, which is of great size, aud exhibits in a re- markable degree the sharp ridges-- 5 or ]o in number--forlning the border of vertical grooves or compartlnents iu which the arlns may rest as in Eucalyp- tocriuus. There are 3 specilnel]s. Fig. 12 has ouly .5 broad grooves, while fig. IO has I.O, with extremely sharp dividing ridges. This pylamid is formed by the sutural union of .5 elongate plates, as is clearly shown bv the interior view of the sanie specilnen in fig. Ioa. This is further confirmed by fiX. I I. which shows a single detached plate of a similar and larger pyramid. Here there is no questiou of a central plate as in the preceding species. ]-[orizon and locality, saine as last. Gazacrinus depressus new species Plate 2, figs. 3, 14 A crushed specilneU from St. Paul of differeut type from the preceding, rather resembling the Tenuessee form. Horizon and locality, saine as last. Gazacrinus ventricosus (\Vachsmuth and Spriuger) Plate 2, figs. 1.5-I6 Idiocrinus ¢,entricosus Wachsmuth and Springer, Ara. Geol., IO, p. I37; N. A. Crin. Cam., I897, p. 2o5, pl. I8, figs. 9 a-b. Specimens verv small, height to width at top of IIBr about 2 by 2. 5 mm. Calvx low, subglobose, but with base excavate and IBB sunken in the cavity. iBr large, elongate, projecting iuward where their extensi«,ns support the teg- minal pyralnid, which here consists usuallv of anchvlosed plates bv the fusion 18 SMITHSONIAN INSTITUTION of which the identitv of the conlponent plates is lost; in this condition the solidi- fied pyralnid is frequently found isolated, while the calyx of the species is ex- tremelv rare and the arlns unknown. These detached pyramids are usually strongiv marked with radiating ridges and groc, ves, as shown in figs. 6, 6a, which converge exteriorly into a fused glohular mass at the center. FrOl]l such examples the inference xould be that in the course af the lnodification of the tegmen incident to COlnpression by the closely packed almS the original function of the structure had been lost. Surface smooth with calyx plates moderately convex. These isolated bodies when first cbserved xvere supposed bv Miller and by \Vachsmuth and Springer to represent the ventral structure of Pisocrinus, specimens of which were numer- OtlS il the saine bed. tIoricon atd locality, saine as last. Gazacrinus ramifer { Roelner) Plaie _, figs. rT-_,r Eucalvplocrin.us tamiser Roemer, Sil. Fauna \Vestl. Tennessee, 8.5o, p. 5L pl. 4 a. b.--Callicrinus tamiser \Vachsmuth and Springer, N. A. Cin. Çam.. 897, p. 358. A large species: calyx wider than high, average about o bv ._, mm. Base broad, excavate, the plates strongly marked by a stellate rira bordering the cavity, which is here wide and shallow. Other ridges passing from BB to RR divide the surface into prominent triangles. IBB fairly large..Arlns long and heavy, directed upward, lying parallel but not so closelv abutting as in the type species. The ventral pyramid is relativelv very large, with only a few sharp ridges, as shown in fig. 9a. It is an interesting fact that Roemer wheu describing this species, one of the rarest known to the early Tennessee collectors, should bave bien led by an indefinable resemblance in the calyx alone to refer it to EucaI.rplocrims, and that \\rachsmuth and Springer, upon the evidence of a solitary specimen which thev had obtained, while in much doubt as to its generic relations, recognized a possible affinity 'ith the other Calyptocrinid, Callicrin««. The shales of the Beech River forlnation have yielded some remarkably fine specimens of this species, throwiug nev light on the relations of the genus, free from the matrix and exposing arms and surface characters at all sides. The clue to the actual structure first afforded by this material xvas later confilmed by the finding of the equally instructive speci- mens of the type species at St. Paul. Horizot a.d locality. Beech River formation, Niagaran; Decatur and \Vayne counties Tennessee. Gazacrinus milliganae (Millet and Gurley) Thysaocrim«s milliganae Miller and Gurley, Bull. 8, Illinois St. Mus., ]896, p. 5[, pl. 3, figs. 23-25. Similar to the preceding, and perhaps only a varietv of it, represented bv imperfect specimens. I ara figurin.q .[iller and Gurlev' type specimen and a DI MEROCRINIDAE I9 couple of others that may l»crhaps go with it. The chier difference ol»servable is that here the lase is less deeply excavate, and the BP,, instead of being raised into a stellate ridge, are sharply nodose, forming a well defined pentagon. Horizon and locality. Beech River formation, Niagaran; from the glades in Decatur County, Tennessee. Gazacrinus stellatus uexv species Plate 2, figs. 25 a-c This species is the onlv instance in which the genus has been recognized from bevond the limits of the Silurian. The unique specimen upon which it is based c(mes fr(ln the Linden formation of the Helderbergiau, the lmver beds of which in some Tenuessee localities lie in verv close relation to the Decatur limestone et the top of the Niagaran, where it almost seems as if there is an intermingling of typical fossils. The species, while in geueral similar in size and proportious to G. ramifer, is clearly distinct in detail. The basal cavity is sharply defined, the edge forlning an acutely pointed pentagon with straight sides. The lï)B and other calvx plates are covered with coarse pustules, which tend to coalesce below into lines forming raised triangles on the radials, but with more isolated rugose lnarkings on the other plates. ]-[orL:on and locality. Linden formation, Helderbergian, Lower Devonian; Hardin County, Tennessee. Two species have been descril,ed by Weller from the Racine dolomite of the Chicago area, and one bv Hall from the Rocbester shale et Lockport as Th3'sanocrims has been re- ferred to the genus. For list and synonymy, see Bassler, Bibliogr. Index, I95, p. 545- LAMPTEROCRINUS Roemer Plate 3 Lampterocrinus Roemer, Sil. Fauna Westl. Tennessee. 86o, p. 4o.--Vachsmuth and Springer, Rev. Pal. , I88L pp. 84, I99; 3, 885, p. lOI ; N. A. Crin. Cam.. 897, p. -'2oT.--Bather, Treatise on Zool., 3, 9oo, P- 99, fig- I24 .--Zitte1-Eastman, Textb. Pal., d ed., 93, P- 87.--Jaekel, Phylogenie und System, 98, p. 4L For further references see Bassler, Bibliogr. Index, I95, p. 689. Clyx snl)tul-lfiuate, similaï to that of Dimerocrin us but asvmmetrical owing to lmlging at anal side; iBr few, anal ilatel-l-adius wider than the others; ravs produced into 5 tulmlar extensions, beal-ing uniserial, pinlmlifel-ous al-ms at each side, with more than one pinnule to a brachial: tegnen composed of numerous couvex plates passing into a strong, sui)central tube; colulnu sharpl3r pentagonal. Gc,otyl, c. Lamptcrocrimts Tenucssccnsis Roemer. Diçrribttiom Silurian : America. In the Revision of the Palaeocrinoideaç pt. ". p. zoo, and in N. A. Crinoidea Camerata, p. ",o7, \Vachsnmth and Springer described the brachial arrangement of this genus as con- sistin of lateral appendages, in which the brachials, from primibrachs up, roofed bv covering pieces were extended into single rigid tubes, or free rays. giving off the arms laterallv. This 20 SMITHSONIAN INSTITUTION was an inference bv Vachsmuth of a structure xx hich had not actuailv been seen, based upon analogy of the Batocrinid genus ._çteyanocrimts. It was criticised bv gather in his review of the Camerata monograph, 6th notice, Geol. Mag., Match, 899, p. I25, callin attention to the fact that our interpretation had hOt yet received confirmation. This objection can now be met by the proved fact. Lampterocrimts is one of the best known and almndant crinoids in the Tennessee rocks, and from Roemer's time on tlm calices were to be round in collections generally. Tbey are firm, strong fossils, with thick plates solidly cemented together, well adapted to resist weathering in the glades. From these rotund bodies the other parts are readily detached, so that untii now no one has ever seen anv vestige of the arm structure. ]3y the fortunate occurrence of some specimens intact in the Neech River shales, protected by the matrix which could be removed by preparation, we are noxv enabled to exhibit the complete crown with all tbe appendages in their natural position. the remarkable series of specimens here studied, there are two with the tubular rays and side arms and the anal tube in place, and four otbers with parts of the radial extensions favorablv located for inspection. There are rive beavy tubes composed of the primibrachs and higher brachials curved like arm plates, with their covering plates, fringed with very long, slender arms given off alternately from each side, and bearing delicate pinnulesprecisely the struc- ture of ._çteyanocri.n.us sculptus of th Burlington limestone. The ide-arms are uniserial, and each ossicle bears two pinnules, one from each side. While the type species remains as the chief representative of the genus, the new material has produced a well defined nmv one with a variant for a possible third. Hall described a smail species L. parwts, from the Valdron sha]e, and a]so one from the Racine dolomite of the Chicago area, from which three species are also described bv \Veller. Rowley described another from the Missouri Silurian. None of these throw anv liht on the structure. See ]assler's Index for list with references. Lampterocrinus tennesseensîs Roemer Plate 3., figs. r-6 Lampterocrimts t«nnesseensis Roemer. Sii. Fauna ,Vestl. Tennessee, 86o, p. 37, pl. 4, figs.  a, b.-- Vachsmuth and Springer, N. A. Crin. Cam., 897, p. 2o9.--Bassler, Bihliogr. Index, 95, p. 69o. This original species, so well known in all collections bv weathered speci- mens from the glades, is strongly chavacterized by its elongate form, sharp stel- late sculpture, and prominence of the anal interradius, which is larger than tle others, and curves over into the tegnen where it passes into the strong sub- central tube, while the lower part is more or less svcollen so as to produce a de- cided asymlnetry. This anal "hump " is a most conspicuous cbaracter, bv which the weathered calices are usually recognized at a glance. The sculpture takes the form of highly raised ridges passing from center to center of the plates, outlining a variety of triangles and hexagonal figures. At the anal side these often connect in such a xvav that thev frm a strong median ridge runnin- the full length of tbe interradius from the posterior basal to the anal tube. The complete crown, free on both sides, was imbedded in a shalv limestone, vhere several instructive fragments of arms also occurred showing their mode f connection and relation to the tubular rays, and especially their bipinnulation, as in fig. 6. This peculiar structure, at one time considered to be an impossibility in crinoid morphology (Crin. Gotland, 893 ' p. 36), is nmv known to exist in several genera. I figure on plate 7 a specimen of Carpocrinus from Gotland in which the two pinnules to a brachial are well developed ; and the structure DIMEROCRINIDAE 2I was fully described in a Devonian genus in my paper on DolatocriJzus, 1 with 2, 3 and 4 pin- nules to a brachial. Since then it bas been further observed by Miss Goldring. Devonian Crinoids of Nev York, 1924, in the genera Clarkeocrinus, p. I8o, and Liparocrinus, p. 397, with like numbers of pinnules to the brachial. This leading species for the Tennessee Silurian was recognized by Troost long be- fore Roemer's time,, and fully described under the name Balanocrinitcs in his unpublished monograph. Horicon and localitv. Shaly limestone of Beech River formation. Niagaran; Decatur and adjoining counties, Tennessee. Lampterocrinus sculptus new species Plate 3, fic3s. 7, 8 A variant of the preceding, from the saine horizon and locality, with a lower and lnore spreading calyx, more dclicate sculpture and more nulnerous ridges. Lampterocrinus roemeri new species Plate 3, figs. 9-r4 Differs from the type species in the nmch plainer character of the surface markings. The ridges are fewer and lnore prolninent, and the rholnboidal areas enclosed by theln are ahnost uniforlnly smooth, alld hot crossed by other ridges ; thus the stellate appearance is largely wantilg. The specilnens all COlne froln a sort shale at a little different level froln the former species. In addition to the small crown with arms and anal tube, fig. o, there are 4 calices with parts of the radial appendages attached, as in fig. 9. and 2o other good specimens, in all of which the characters above mentioned are constant. I[ere aL, o mav be seen the sharply pen- tagonal stem characteristic of the genus, with concave sides, as shown in figs. 9 and Io. I have caIIed this species L. rocmcri, in honor of the founder of the genus. Horizon and locality. Soif shale of the Beech River formation, Niagaran" Tuck's Mill, Decatur County, Tennessee. genus and species indet. Plate 3, lqg s. z5, r5a This fragment, of which there is not enough of the calyx left to indicate its generic relations, is figured on account of the very unusual feature of a hexagonal stem. almost un- known among crinoids. Aside from its six-sided section, the stem in detail strongly resembles that of Lamptcrocrimts, and the specimen may be only a sport from that genus. Horizon and locality, saine as last. genus and species indet. Platc z, lqgs. IQ-22 Stem fragments of unkllOWll crinoid froln St, Paul, ]ndiana. t Bull. II5, 1_1. S. Nat. Mus., I92I, pp. 5. 8. 22 SMITHSONIAN INSTITUTION Familv RHODOCRINIDAE Roemer This dicyclic famil.v, similar to the Dimerocrinidae except tbat the radials are separated ail around, is introduced to receive a number of peculiar t'orms fallin.,o- within its limits t"or which it has leen necessary to propose nexv genera. Paragazacrinus rotundus new genus and species Plate 4, fi(,qs. >4 O11 account of the strong resemblance c»f the tegminal parts this small species was af first supposed to be a varietv of Ga.:'acris; but when it xas round tiret in three gc»od specimens the RR were separated all around bv truncating all 5 BB that interpretation became untenal)le, and there seemed no recourse except to place it as a new genus under the Rhodocrinidae. There are 5 IBB sunken in an indented pit, and 4 or .5 large iBr in the CUl) separating the ravs up to the tegmen, which branch and become free cm lhe first IIBr, giving o arms in all, which are hot flrther known. They test in grooves bounded by ridges forming a ventral pyramid which is surnmunted by an elongate spine. This is sulported bv 5 tegmen plates, the exact relation of which is dicult to determine, but they are thought to be interamlmlacral in position. The three rotund calices are figured, t(Nether with a detached central spine, as to which the question remains open whether it mav hot belong to Ga.vacritus, although it is helieved that the spine is a separate element covering the pyramid. The two ¢orms are from tbe saine localitv and formation, but whether ff-oto the saine laver is hot lmown. Horisou and locality. Laurel limestone, Niagaran ; St. Paul, hMiana. Paulocrinus biturbinatus new genus and species Plate 4. fi9s. 5.5a-c This genus and species are proposed for the reception of a solitary calyx, which both in general form and in cup structure is totally unlike anv other lmown from the Silurian. It is large, rbust, with truncate conical CUl) spread- ing to the arm-bases, and frm there c,ntracting to an opposite cone consisting of a many-plated tegmen passing into a large, subcentral anal tube. The calvx plates are lhick and strongl)" elevated, those «f the tegmen rather nodose, and those of the cup more r less acuminate, and ornamented bv radiating- ridges. The most peculiar thing al»out tbis form is tbe base, forming the truncate end of the dorsal cone. There are 5 IP, B surrounding an enormous lumen, and no two of them alike, 3 slnaller and pentagonal on the posterior and left posterior sides ; the other 2 hexagonal and truncated bv 13B are larger than the former 3 combined. A similar inequality pervades the BB but reversed in position as if compensatory, tbe two larger being the posterior and left posterior (see diagram, fig. 5c). Also the Rit are nacre or less tmequal, and asynametric in RHODOCRINIDAE 23 form, two of them connectiug with the I P,[l. Arm olenings 4 to the ray, directed horizontally from a projecting rira ; the r. post. ray bifurcates on the first IBr, but by way of compensation this is followed by more than two III;r: the amas not preserved. AI1 this l)oints to an abnormal specimen, or sport--but of what ? The form and genera! structure of the calvx are positive and xvell defined, and in alI the collections from St. Paul and the Tennessee localities nothing bas been round with which it can be compared. Therefore it will have to stand upon the above description until the normal form is shown bv further discoverv. Horizon, and locality. Laurel lilnestone, Niagaran; St. Paul, hdiana. Wilsonicrinus discoideus new genus and species Plate 4, figs. 6, 6a This is another Rhodocrinid straggler frOlll the St. Paul beds, knov,n onlv bv the single type specimen, and apparently without close relatives. The calyx is a broad, wheel-shaped disk, wifi smooth plates, slightly convex below and contracting above to a large subcentral anal tube. ]t has 4 IBB sunken into a small indented cavity, BB fairly equal in size, truncate above and connecting with single large iBr. Arm-openings to, small and widelv separated, issuing from a series of cuneate llBr. The outstanding feature of thi,; genus is the fixed lfinnules origiuating upon the longer face of the IIBr to the number of 4.5 or 6 on each side in the form of more or less irregular pinnulars, which by contact with the IIBr and with each other are incorporated in the cup; they lead directlv to interbrachial openings for free pinnules independent of the arms, emerg- ing at the margin of the tegmen between the ravs and their subdivisions. These are verv con- spicuous, corresponding in number to the incorporated pinnules. Thus the interbrachiaI areas, above and bevond the single large iP, r plates which abut upon the truncated BB, are occupied by these fixed pinnules, which have every appearance of higher iBr. For a fui1 discussion of the fixed pinnules lu various genera and the interpretation of their openings at the mar.q-ila of the tegmen, see my papers on Scyphocrinus  and Dolatocrim«s? The type specimen was round by mv former assistant, the late Dr. Herrick E. \Vilson, who recoguized its highly distinctive characters, and the generic laame is proposed in lais memorv. Horizon. and locality. I.aurel limestone, Niagaran" St. Paul, Indiana. Emperocrinus indianensis 5Iiller and Gurlev Plate 4. ficjs. 7, 7a Em.perocrinus indianensis Miller and Gurley. Bull. 6, Illinois St. Mus., I895, p. 43, pl. 4, figs. I6, I7.-- Bather, Treatise on Zool., 3, I9oo, p. 2o2.--Bassler, Bibliogr. Index, I915, p. 476. Another rare form, of simpler construction than the preceding, which I ara illustrating from a new specimen. Instead of being discoid, the calvx is pentagonal, and the iBr areas, instead of bein, filled to the margin with the incorporated pinnules, are depressed, contracted and limited to the single large  Smithsonian Publication No. 244o, I917, pp. 33-37, 4c-46: pl. 9, figs. 5-6. e Bull. 115, U. S. Net. Mus., 192I, pp. 24, 25, pl. 7, figs. 2-5. 24 SMITIISONIAN INSTITUTION plate. There are a few openings £or ree interbrachial pimIules, apparently only one to each ami on the outer side of the ray, lying close under the ami- base. These structures were hot brought out in the original description, and whereas the number of II] is there said to be three, it is distinctly rive in my specimen. Iiller and Gurley treated the enus as belonging to the Flexibilia. Hori«on. and locality. Laurel Iimestoue, Niagaran; St. Paul, Indiana. Rhodocrinidae gems and species indet. Plate 4, fis. 8, Sa A fragment with onlv part of the lase, attached in a slanting position to a very large stem. There are 4 IP, B at the botton of an indented cavity as in severaI of the associated forms, and entirely covered by the stem. None of the others of this family here described have any part of the stem preserved, and it mav be that, large as it seems, this is the normal type for the group. But the sloping attachment to the calyx is unusual. The BB are truncate for a connection with the succeediug iBr, separating the RR, so it probably belongs here. Horizon. and localitv. Laurel limestoue, Niagaran; St. tanl. Indiana. Lyriocrinus melîssa t l all Lyriocrinus melissa, Hall, 28th Rep. New York St. Mus. Nat. Hist., 1879, p. 1.39, pl. 15, figs. I8--W; Ilth Ann. Rep. Indiana Dep. Geol., 1882, p. 269, pl. 14, figs. 18--'7, pl. I5, fig. II.Wachsmuth and Springer, N. A. Crin. Cam., 1897, p. 263, pl. ii, figs. 4a-l.--For complete synonymy, Bassler, Bibliogr. Index, ]ull. 92, U. S. Nat. Mus., I9IS, p. î'î'4; also for the genus, and other species, p. 773. This very typical Rhodocrinid species is one of the leadinx fossils in the \Valdron for- mation, occurring abundantly at the type locality, Waldron, Indiana, and in the rich exposure of \Valdron shale at Newsom, near Nashvitle, Tennessee; it has also been identified in the Racine dolomite of the Chicago area. Reference to the thorough discussion and illustration of the species by Hall and by Wachsmuth and Springer MI1 afford alI needful information, and it is accordingly omitted from consideration here. Another fine species, L. dactylus, was described by Hall froln the Rochester shale at I.ockport, of xvhich unusually perfect specilnens from Grimsby, Ontario, are in tie Sir Ed- lnund Walker collection in the University of Toronto. I bave an undescribed specimen from Dudley, indicating the presence of the genus in the English $ilurian. MELOCRI NIDAE Family MELOCRIXIDAE Zittel Of this extensive lnonocyclic falnily, with the radials in contact all around, the collections here in hand contain eight genera, two of them foreigners now first recognized in this country, one which thougi known belote has developed an unexpected wealth of species, and one new. MACROSTYLOCRIN US Plate 4 Macro«tylocri»zu« Hall, Pal. New York, 2, I852, p. 2o3.--Wachsmuth and Springer, Rev. Pal., , I88L pp. 96, xo2; N. A. Crin. Cam., x897, P. 285.--]ather, Treatise on Zool., 3, xgoo, p. 6œ.Zittel- Eastman, Textb. Pal., d ed., x93, P. 9L--Jaekel, Phylogenie und System, x918, p. 36.--Bassler, Bibliogr. Index, Buli. 9 -9, U. S. Nat. Mus., x95, P- 782. BB 3 unequal: anal interradius wider than the others above level of RR; arms IO, simple, biserial. Gcnotype. Mcrostylocrinus ornatus Hall. Distribntion. Silurian and Devonian : America, England. This typically Silurian genus, but now known to occur in the Lower Devonian, a which has hitherto been accounted as one of the rare fossils, is well represented in the present collec- tions, especially for illustrating the structure of the tegmen, heretofore unknown. Several species are figure& all but one previousl.v described, and of these it is hot deemed necessary to repeat the descriptions. Macrostylocrinus fasciatus Hall Plate 4. fi9 s. 9, ça. b Macro«tylocrinu« fa«ciatu« Hall, 28th Rep. New York St. iIus., 879, p. 3o, pi. 3, figs. 5, 6.--Wachsmuth and Springer, N. A. Crin. Cam., 897, p. z88, pl. zz, fig. 3.--Bassler, Bibliogr. Index, 95, P. 78. The specilnen here figured has the fasciculated striae, rardv well preserved. perfectly distinct, and shows correctlv the full dimensions of the calyx and the forln and proportions of ail the plates. The important feature, however, is that it has the tenen intact, which bas not been round belote. Usuallv the upper part is broken away, so that the great elongation of the cup does hot appear. The tegmen is composed of a great number of slnall smooth plates, traversed fl-Olll the center to arm-bases bv narlow, almost linear, ambulacra. The small anal cpening lies at the extreme lnarKin, where it projects between the tv«o posterior rays, connecting with the median row of anal plates on the dorsal side. Radial series sharply defined bv a lnedian ridge. Total height of calvx 13 111111. Hori»on and loc«lity. \Valdron shale, Niagaran ; Hartsvilte, Indiana.  Springer, Unusuai Forms of Fossil Crinoids. Proc. U. S. Nat. Mus., Vol. 67. 9-'6. p. 35- 26 SMITHSONIAN INSTITUTION Macrostylocrinus granulosus Itall Flate 4. figs. fo-z3 Macrostylocrinus striatus var .qramtlosus :Hall, 28th Rep. New York St. Mus., I87o. p. I29.--\Vachsmuth and Springer, N. A. Crin. Cam., 1897, p. 289, pl. 22, figs. I5a, b.--Bassler, Bibliogr. Index, I915, p. 782, 783. There is here illustrated a fOrlll with turbinate calvx, expanding upward as most frequent in the gelms, in which the tegmen is also beautifully preserved in two specimens. This is of a somewhat different type, in accord with the more spreading fornl of the calyx, in which the ambulacra tend to becolne wider, and the anal opening very nmch larger; it is situated in the depressed posterior interanlbulacrum between the nlargin and the center, and in one specimen is closed by a pyranlid of slnall plates. The granulose surface, completely devoid of striae, together with the general form and proportions, seems to indicate the reference to this species. It is verv small, as is best seen bv comparing the draw- ings, which are mostly double size. Hori:on a»td localitv. \Valdron shale, Niagaran ; Madison, ]ndiana, Newsom and perhaps Decatur County, Tennessee. Macrostylocrinus laevis new species Plate 4. figs. 4-9 This naine is suggested to desiffnate a snlooth form occurring rather plen- tifullv in the Beech River formation, having relatively small RR and wide IBr, and in which we bave the stout biserial arms partly preserved. Horizon. md local#y. Beech River formation, Niagaran : Decatur County, Tennessee. Macrostylocrinus meeki (Lyon) Plate 4, fios. o-:2 • 4ctitocrimts mceki Lyon, Proc. Acad. Nat. Sci. Phil., x86t, p. 4ri, pl. 4, figs. 4a, b.--Macrostylocrinus meeki, Wachsmuth and Springer, Rev. Pal., , p. xo3 ; N. A. Crin. Cam., x897, p. 29o, pl. 2, figs. 6a, b. A broader and more rotmld calyx than usual in the genus, and notable ¢or the shar nledian ridges which follow the ravs from radials into afin-bases; it mav also be more or less striate. Horizon. atd local#v. Louisville limestone. Iefferson County, Kentuckv, and Black River formation, Niagaran; Decatur Count)-, TennessC. " (?) Macrostylocrinus pustulosus new species Plate 4, fig.«. 25, -Sa It is hot clear that this tlniqtle specimen belongs to the genus. The general contour and pustulose ornament would seem to ge exceptional, while the arrange- nient of the anal side is consistent with the reference. In the large side of the RR it bears considerable resemblance to the early Platycrinidae, and if we had the terrien preserved it nlight be fcund to go with Clicocriuus 2I ELOCRI N I DAE 27 Hori,r, on. aod locality. Beech River forlnation, Niagaran ; Decatur County, Tennessee. Of other species there is 3[. stria.tus Hall from the \Valdron, three from the Racine dolomite, one from the Rochester shale (see Bassler's Index. p. 782) ; and a thoroughly repre- sentative species froln Èngland, 3[. anglicus, by Jaekel. M. indianensis Miller and Gurley, from St. Paul, does not belong to the genus, and mav be a Patelliocrim«s. I aih figuring (.pl. 4, fig. -'24) a complete specimen of the type species, M. ornatus, from Lockport, New York. MELOCRINUS Gc,ld fuss Platc 5 3lclocrinitcs Goldfuss, Petref, Germ., 8-6, p. 97- Mclocrims, Agassiz, Ann. Nat. Hist., 838, p. 447.--Wachsmuth and Springer, Rev. Pal., , I88I, p. 8; N. A. Crin. Cam., 897, p. -9z.--Bather, Treatise on Zool., 3, 9oo, p. 6L--Zittel-Eastman, Textb. Pal., ed ed., I93, p. 9o.--Jaekel, Phylogenie und System, 98, p. 3z.--Goldring, Devon. Crin. New York, 9z3.For complete list of references and table of synonyms, Bassler, Bibliogr. Index, Bull. 9, U. S. Nat. Mus., 95, P. 794. BB 4, unequal; iBr numerous, anal interradius but slightly distinct; ravs produced into two main rami, giving off unilateral, pinnulate arlns, uniserial or biserial, to the outside of the dichctoln: the rami mav be separate (Silurian species), or mare or less fused by their limer lnargins (Devonian species) : column round. Gcnotype. Mclocrimts hicroglyphicus Goldfuss. Distribution. Devonian and Silurian; Germany, Gotland, England, America. Few genera have had so much written about them as this, or have been treated under so manv different names, as will be seen bv the list of references in the P, ibliographic Index. The most recent discussion is that 1,y ,hliss (;oldring in the monograph of the Devonian Cri- noids of New York. of which this genus and its allies form a most important part of the fauna. I titherto it has been allnost negligihle anaong American Silurian fossils, the few species described being neither characteristic nor well represented. That which gives a renewed interest for this work is the discovery of a single specimen in the 13eech River formation showing a wide distribution of the typical form, and the parallelism of its occurrence in this country and the north European Silurian. Verv conspicuous species of what I regard as the Silurian type of the genus have been found in England and Gotland, some of them described by Angelin. Now for the first time we have a parallel to them from the American Silurian. Melocrinus tennesseensis new species Platc 5, fig. z Although the calyx plates of this unique specimen are SOlnewhat disturbed. the decisive features of the rays are well preserved, and the general aspect of the fossil points Unlnistakablv to a close relationship with the t.vpical fcrms of England and Gotland. For comparison I ana fi.uring two specilnens of an abundalat species from Dudley, England, which if nc, t elsewhere described mav be taken as :1I. spcctabilis of Angelin (pl. 5, figs. _% 3)- The remarkal»le simi- larity of type in the two fOrlnS is apparent at a glance,--even the stem of one being ahnost a duplicate of the other. Evidently the calvx of the American species is much the shorter, the base of the cup less turbinate than in the English form, and the iBr in the latter lnore ntlmerouslv dex;eloped. Horicon and localitv. Beech River formation. Niagaran • Decatur County. Tennessee. 28 SMITHSONIAN INSTITUTION Melocrinus oblongus Wacllsmuth and Springer Plate 5, fiç«. 5, 6 Melocrinus oblon9us Wachsmuth and Springer, N. A. Crin. Cam., p. 2oo, pi. 22, figs. 9, I2. Confined to the higher Niagaran beds. Tv,'o specimens are figured espe- ciallv to show the division of the ravs into txvo rows o brachials, for compati- son ,vith the similar elongate form "referred to Roemer's Cytocrinus v«ith only one such row. Horizon and locality. Louisville limestone, Louisville, Kentucky, and Bob formation, Niagaran ; Decatur County, Tennessee. Other Niagaran species are M. obconicus Hall, of the Waldron beds, M. aequalis S. A Miller, of the Laurel; one from Missouri by Rowley, one from the Racine dolomite of the Chicago area and one from the Rochester shale at Lockport. Melocrinus onondaga nexv species Plate 5, fig. 4  figure here what appears to be a very young stage of the genus from the middle Devoniau, which is interesting for the remarkable shortness of the calvx compared with the well developed arms. Horizon a,d locality. Onondaga formation, Iiddle Devonian; Sylvania, Ohio. Cytocrinus laevis Roemer Plate 5, fi9s. 7, 7a, 8 Cytocrhu«s laevis Roemer, Sil. Faun. "Vestl. Tennessee, 86o, p. 46, pl. 4. figs. 2a-c. Melocrinus roemeri Wachsmuth and Springer, N. A. Crin. Cam., I897, p. 3m, pi. 22, figs. IIa, b.--Bassler, Bibliogr. Index, 95, PP- 795, 796. The brachials in this form are extended into 5 trunks composed of a single series of plates, which is a good generic distinction from similar lobate species such as Melocrîmts oblon9us, according to the pract;ce follov,'ed in other groups ; while the arms themselves bave hot been seen, the direct succession of primi- brachs into the arm opening shows how thev must be. Horizon and local#v. 13eech River formation, Niagaran; Decatur Count?-, Tennessee. MARIACRINUS Hall Plate 5 Mariacrhu«s Hall, Ara. Jour. Sci. (2), 25, I858, p. 278; Pal. New York, 3, I86I, pp. o4, I39.--Wachsmuth and Springer, Rev. Pal., 2, 88I, pp. I4, II8, 233: ibid., 3, I885, p. 326; N. A. Crin. Cam., I897, p. 281.--Zittel-Eastman, Textb. Pal., 2d ed., I913, p. 19o.--Goldring, Devon. Crin. New York, I923, p. o9.Bassler, Bibliogr. Index, 915, p. 785. BYI 4; similar to Mclocrinus, but arms free, bralching once or twice, with alternating pinnules or ramules. Genotype. Mariacrimts phtmosus Hall. Distribution. $ilurian, Devonian: America, England, Gotland. MELOCRI N IDAE 2 9 Mariacrinus carleyi (Hall) Plate 5, figs. 9, IO Glyptocrim«s carlcyi Hall, Trans. _A_lb. Inst., 4, 1863, p. 203; 28th Rep. New York St. Mus., I879, p. I32, pl. I4, figs. 7-IO.-lariacrinus carleyi, Wachsmuth and Springer, N. A. Crin. Cam., 1897, p. 282, pl. 22, figs. 2a-c.--Bassler, Bibliogr. Index, 1915 ' pp. 785, 786. A very elongate, turbinate species, widely distributed and round at ail the principal \Valdron localities, and also in the Laurel. The specimen from the latter here figured lacks the sharp radiating ridges upon the loxer plates usual in the \Valdron specimens, the gralmlose surface predominating, but in the other characters the two agree. \Valdron shale, Niagaran: \Valdron and Hartsville, Indiana, and Newsom, Tennessee; also Laurel limestone; St. Paul, Indiana. Mariacrinus aureatus S. A. Miller Plate 5, figs. _r_r, _rza Mariacrinu« aureatus Miller, 17th Rep. Indiana Dep. Geol., 189oe, p. 644 (adv. sheets, 1891), pl. 6, fig. 36. A broadlv rotund species, in almost every way the reverse of the preced- ing, especially in the hihly sculptured ornament which covers the eutire cup with delicate, stellate figures. I4orLon and localiy. Laurel limestone, Niagaran; t. Paul, Iidiana. Mariacrinus sp. Plate 5. fig. z3 This specimen, associated with Mclocrinus in the beds at Dudley, illustrates the pres- ence of the txvo closely allied genera there as here: it shows the arms branching in the usual way, which is the distinguishing character. I4orion and locality. \Venlockian, Silurian: Dudley, England. (?) Mariacrinus rotundus ne»v species Plate 5, figs. z_, This is one of some stralage forms from the topmost Silurian, occurring in close relation to the Lower Devonian. It is so utterly different in general aspect from an)" other species of this or allied genera that it is placed here with much doubt. If seen in a v«ell weathered condition in a miscellaneous collection. the specimen would without hesitation be taken for Dizygocrinus rotmdus of the ]3urlington limestone. Yet according to the structure of the cup as plainly delineated, with no anal plates, and radials in contact all around, it must belong to the Melocrinidae, having abnormally small basals which cannot be defined in the narrow indented cavitv, compensated bv relatively large radials. The highly rounded teela is filled with numerous but very definite plates pierced by a small subcentral anal opeuing, while the i]3r in the cup are but few. [-[orizon and locality. Decatur limestone. Niagaran; below Grandviexv in the bluffs of the Tennessee river, Perrv Cotlllty, Tennessee. Associated xvith .4orocrinus nodosus, infra. 3 .0 SM ITIISONIAX INSTITUTION ALLOCRINUS \Vach¢,muth and Springer ]'late O .qllocrinus \Vachsmuth and Springer, (;eoi. Surv. IIlinois, 8, 89o, p. 2; N. A. Crin. Cam., I897. p. 3o6. Eather. Treatise on Zool., 3, , P- 6.--Zittel-Eastman, Textb. Pal., zd ed. 913, p. I9[.Jackel, Phylogenie und System, 98, p. 36.Eassler, Bibliogr. Index, 95, P- zS- ll 3, unequal, i)-l-sal CUl» h,w an(1 bra(l. N anal ldates: ill- , large. Arms o, unisel-ial. Gcnotyc. ,lllocrinus t3'us Vachsmuth and SlWinger. Distribution. Si]urian ; America. This genus was proposed upon the basis of very scant material, consisting of a calvx and a detached set of arms. The extremeiv iow and Iwoad contour of the former with its concave base. and the massive character of the latter, marked it as thoroughly distinct, con- firmed later I,y a second species from a different horizon, also described from a poor sl)eci- men. Vhile hopilg for further information, I was agreeably surpried at the xvealth of new materiai disclosed by the Telmessee collections, containing hot only immerous excellent speci- inens of the type species, but also of at ieast two others, among them some with almost the complete crinoid beautifu]]y preserved. Only a few of these are 5hown bv the drawings. Ailocrinus typus \Vachsmuth and Springer Plate 6, fils. -4 Wachsmuth and Springer, Geo[. Surv. Illinois, 8, 89o, p. "o7, pl. 4, figs. 7-8; N. A. Crin. Cam., 897, p. 3o7, pl. 24, figs. 7a, b. The hmg, 1,-,ad and s«,mewhat convex uniserial brachials give to the arms an aspect of lnassiveness and simplicity. Having a shallow, concave bae. with radials forling part «)f the cç, ncavity and projecting into a prominent rira at the margin, tbe calyx is fairlv l)road and exl)al(ls upward t the afin-bases. Cup plates all strongly ne,ch,se. With c,ne of the well preserved crowns we are able to show the round stem, with its rather long c,,hmmals, to its full length, with terminal roots attached indicating attachment to a soft bottera. Ilori:on atd localitr, l]ee:h River formation, Xiagaran- Decatur and Vzvne counties, "1 ennessee. Aliocrinus ponderosus new speci«s Plate 6. fi(qs. 5, 6 Similar tc the t.vle , but differing in the eXtl-clnely 1)(l(lel-(ts arlS, widelv swollen in the middle, c(mbined with a verv sh-rt and narr(w calvx. Horieot and local#v. Ileech River formation. Niagaran : Decatur County, Tennessee. Ailocrinus longidactylus new species Plate 6_. I)istinguished ly extrelne length and relative slendel-ness of the arlllS, which impart a different aspect to the complete crown. Thus tbe arms lie much IELOCRINIDAE farther apart and afford a vi«w ,f the cl«)se fringe of pimlules, which are scarcelv visible in the preceding species. The calvx is relativelv broader, and the ne, des upon the CUl» plates are verv consl)icu,_,us, especially the single large iBl" which l»v its central ncde stands out distinct fron the others. One specirl'lel is characterized bv excessivelv lar.-e radials. Horizon and localitv. Beech River forlnation, Niagaran : Decatur County, Tennessee. Allocrinus benedicti S. A. 5Iiller Plate 6, figs. __. _ œe .lllocrimts be»wdicti Miller, 7th Ann. Rep. Indiana Dep. Geol., 892, p. 64ï, pl. 7, fig. I---\\rachsmuth and Springer, N. A. Crin. Cam., I897, p. 308, pl. 24, figs. Sa,/9. çliller's fiï_.ure gave no idea cf generic or .specific characters, beia ruade fr,,m a fragment. I ara figuring two gcd crowns tc show the f,,rm as it Jccurs in the ].autel. in which the calvx plates are me, re br,,adlv r,,unded and the arms rather less rolm.t than in the type. Hori::on and localitv. Laurel limestone, Niagaran: St. Paul, Indiana. PATELLIOCRINUS ,\n?_.elin Plate 6 Patelliocrlnus Angelin, Icon. Crin. Suecc. I878, p. L--Zittel, Handb. Pal., 1879, p. 368.Vachsmuth and Springer, Rev. Pal., z, 88I, p. IOo.Bather, Treatise on Zool., 3, o, p. I6z.Zittel-Eastman, Textb. Pal., 5d ed. I913, p. I9t.Jaekel, Phylogenie und System, 1918, p. 36. tl 3, unequal, 1 )wsal CUl» ehmgate. 'o anal plates; iIr few. Arms biserial or cuneate uniserial. Genotypc. Patclliocrimts pachydactyhts Angelin. Di«tribution. Silurian ; Gotland, America. This Gotlandian genus, now for the first time doubtfullv recognized in America, while having a simple calvx with 3 I[ and a large iBr with anal side lOt differentiated, is widely separated from the !weceding bv its elongate, conical cup and biserial arms. Angelil de- scribed 9 species in which there is considerable confusion of çeneric characters. The figures cannot be depended on (Bather, Crinoidea of Gotland, p. 5) for details, aud it is hard to tell exactly what should be considered as the type. But I have taken P. pinmtla.ttts, pl. 2 4, fig.., as a fait representative, and there is anaong several of the species a general similarity which seems to warrant the reference of out species, in default of anything better. Patelliocrinus ornatus new species Plate 6..figs. z3-5a The surface, as shown by several specimens, is almost invariably ornate, with variations in intensitv due to erosion or growth. ]t is best shown bv figs.  5,  Sa, ¢rom a ¢ree specimen unusuallv well preserved, in which the stout biserial arms and crowded pinnules are in place. The relativelv small radials 3 2 SMITHSONIAN INSTITUTION are comlnon to all the specimens. It is probable that the specimen named by Miller and Gurley Macrostylocrinus indianensis, Bull. 6, Illinois St. Mus., pl. 3, fig- 33, belongs to this genus, but the figure is too indistinct for comparison. Igorizon and localiry. Laurel limestone, Niagaran; St. Paul. Indiana. Patelliocrinus rugosus nexv species Plate 6, fi9s. 6-18 Vith its strong rugose sculpturing, this species may le distinguished from the preceding bv the great preponderance in size of the radials. Hori:on and locality, saine as last. Patelliocrinus laevis new species Plate 6, fic.qs. 9, 20 Differs from the two preceding 1Lv its perfectly: smooth surface and greater elongation of calvx. Horizon. ad locality, saine as last. genus and species indet. Platc 6, figs. 2z-2zb An apparently complete crown, having a low calyx of smooth, rounded plates, three snaall unequal BB, large RR followed by a singlë IBr wlaicla is axillary, filling most of the distal face of the R, and supportiu two stout, biserial arms. There seems to be a single iBr, mostly hot verv well defined, but witla the posterior one the largest, and no other indication of anal structures. It would seem that with so manv details available it should hOt be difficult to de- termine the systematic position of this fossil, but after repeated efforts, aided by consultation with colleagues, I aln still obliged to confess mv inability to treat-it intelli.o4ently. It is doubtless a new genus, but wbere to place it. I do hot knmv. So I aln giving the facts as I and the artist see tbem, aud leaving it to others to continue lhe -uessing. Hori»on and locality. Beech River forlnation, Niagaran ; Decatur County, Tennessee. LAURELOCRINUS new genus Plate 7 This genus is proposed for au asselnblage of peculiar fOrlns from the St. Paul beds, which will hOt fit into anv alreadv known. But for the tripartite base it might go under Clonocrinus. but that would mean rather wide variation from the type. Our specimens, while in considerable number, are all deficient in tbe upper part of the calvx and crown, so tbat we are without information MELOCRI NIDAE 33 as to the arms, or even with certainty as to the higher brachials. The characters are an etongate calyx, cylindrical or slightly contracting upxvards; base com- posed of 3 small BB, unequal, forming with tbe RR a broad, flattened, or shal- loxv concave disk; RR very large, curving below into the base and upward into the sides of the cup; I Br and iBr bave peculiar variations--the latter usually one elongate plate with or witbout a small one in succession. Four species are indicated, based upon rather mincw differences viaibte in the specimens as preserved. Gcnotype. La.urelocrinus pa.ulcn«is new species. Distribution. Silurian ; America. Laurelocrinus paulensis nexv species Plate 7, figs. -8 A large, robust species, with broad base and sides rMng nearlv straight; first IBr quadrangular, usuallv about square, and iBr elongate, 6- or 8-sided, followed by a second one mucb narrower; or exceptionally IBr mav be elongate and iBr acuminate, hot followed by a second; axillarv IBr short, followed bv 3 IIBr, the third axillary, indicating probably four arlns to tbe rav. BB lilnited to a sballoxv cavity, occupied largely bv the cohmm-facet witb verv large lulnen. Surface smootb. Horizon and locality. Laurel limestone, Niagaran; St. Paul, Indiana. Laurelocrinus wilsoni nexv species Plate 7, figs. 9-3 A much smaller form than tbe preceding, even more so than tbe drawings indicate at first glance, those of the latter being natural size and of this enlarged bv one hall; and it is of similar contour; first IBr hexagonal, ter 5-sided, fol- lowed by one or t»vo others. Arms apparently 4 to the ray. Surface in lower part tending to be striate. Horizon and locality, saine as last. Laurelocrinus gibbosus new species Plate 7, figs. 4-6 A similar calyx but much more rounded, witb extremelv large RR and iBr, and small quadrangular IBr, ail strongly gibbous; base somewhat convex, with small column lacet and pentagonal lumen. Horizon and locality, saine as last. SM[THSONIAN IX STITUTIONT Laurelocrinus spinoradialis new species Plate 7, ficjs. I7-zïb . mediuln sized species, with R R arlned with sharp spines 1)rojecting dow- ward: first lfr quadrangular, short; ilr 2 in successi¢,n, very elongate, 8- or -sided ]lBr 3 in series, the first verv lavée, the next two llarr¢w and divided lw an ilIBr, the third axillarv, indicating 4 avms te» the var. ]',ased on the unique slecimen fi,.e,u r ed. HorLvolz azzd locality, saine as ]ast. CLONOCRINUS (...)uenstedt I hot t )ehlert) l'late 7 Clonocrim«s Quenstedt, Petref. Deutschl., 4, 876, p. 638 (hOt Oehlert, 879).Bather, Treatise on Zool., 3, 9oo, p. 62.ZitteI-Eastman, Textb. Pal., 2d ed. 193, p. 9o.Jaekel, Phylogenie und System, 98, P. 32. Corymbocrim«s Angelin, Icon. Crin. Suecc., I878, p. 8.Zittel, llandb. Pal., 879. P. 373.Wachsmuth and Springer, Rev. Pal., 3, 885, p. . I 4, hidden bv column" ir few, ne lav-e fl,llowed l)v small ones in vertical ri, w" no anals. Amas dich ,t, ,m, ,us, lfiserial below and above the lfifurcati ms. Gcnotype. Eucalyptocrimts polydactyhts McCoy. Distribution. Siluriala Gotland, Enland, America. Tbis g-ems is regarded as ]eadin- from the _Xlelocrinidae towards the Calyçtocrinidae. having a simi]ar distribution of the cup idates, but with i[lr bevolad the first hot paired, and the arlns hot resting in COlapartments between partitions. It is essentially a Gotlandian form, of which six pecies have been described tmder tbe naine Çorvmbocrimts. The genus is doubt- fullv recognized here from SOlne imlerfect specimens derived frlaa a formatiola which has produced a number of new and strange fol-ns, one of which is figured. Clonocrinus occidentalis new species Pate 7, fins. I8, zSa tIas deeply StlllkCll lasal cavity, with the slnall /3[ at the botte, m: and the i Ir folhwin the fivst in sin,.o_,-le vertical succession. This may be compared with Corymbocrimts hwz'is Ang., pl. 23, fig. 20. ttorizon and local#v. Decatur limestone ; near l'erryville, Tennessee. CALYPTOCRIXI DAE 35 Familv (AI.Y I'T CRINI DAE Angelin 5hmocvclic. Dcwsal CUl) usuallv with 4 P'P' and concave ba,e; hmer brach- ials and interlwachials incorp«wated in CUl), which above the base is perfectly lentamerous; plates of calyx usuallv limited to a definite number; radials in contact all al-mnd : n,- anals" arms, usuallv _o. resting in pairs in cmpartments fol-med hv vertical l)artitions ]orne lv pr«cesses rising lCr(m the fixed iBr and il I Br t« varyin, heights" teglnen elevated i_ a central anal tube, arld composed 'f 4 circlets of large plates vari«mslv shaped bearing the partiti(ms. Silurial» and Devcmian. For instructive diagrams illustrating the structure, see N. A. Crin. Cam., 897, p. EUCALYPTOCRINUS G,-,ld fuss Platcs î, ?. 9 Eucalyptocri»dtcs Goidfuss, Petref. Germ., 8-6, p. e 4. Eucalyptocrim«s. Agassiz, Ann. Nat. Hist., 838. p. 447.Vachsmuth and Springer. Rev. Pal., 3, P. 7; N. A. Crin. Cam., 7. p. 33z-Bathe r, Treatise on Zool., 3, ]o. p. 64.Veller, Bull. Chicago Acad. Sci., 4, pt. ], goe, p. mz.Zittel-Eastman, Textb. Pal., 2d ed., 93, P. gz.Jaekel, Phylogenie und S'ystem, I018, p. 3z.Çomplete reference with iist of synonyms and species, Bassler, Bibliogr. Index, 95, PP. 5o-5o7. Clyx el«mKate to wide spreading" BB 4-. at 1)cttom f an inverted fulmel fiwmed bv RR at le sides, followed bv l-Br. lier and ll-lBr. 2 each iBr one large 8- or o-sidcd. angular al)ove. SUlq«,rting a pair ,f ehmgate plates of second range extending upward l,etween the afin-bases t,, a connecti,m with the partitions" a single iI [tIr «f similar f«,rm rests Ul)m the truncate second l-Br and COllllects with the partition in line with the rav. Xo anals. Al'lns biserial, paired, restin in o vertical c,,mpartlnents botmded bv pal-titi,ms sup- p¢wted bv lw«cesses arising fl-Om the iBr and ilIBr plates extending the full height of the tegmen and lneetin al»ove in a circlet of peripheral plates. Teglnen COlnposed usually «)f 4 ranges of plates, ttl»ulal-, expanding upward into a canopy having an inner set of plates variable in lmmlmr, often 4, surrounding a central anal ,q)ening, either direct, or produced into a short tube. Gcnotypc. Ettcal3'ptocrinus rosaccus Goldfuss. Distribution. Silurian" Gotland, England, Anml-ica. 3ne species in Middle Devonian, GerlllallV. This prolific Silurian gelms, first described froln a Devonian species, which still remains the olllv olle klloWil frOlll that epoch, has bv the growth of research becolne the leading known crinoid of its typical horizon, both in variety and distribution. Some 4o species have now been described froln the Eurol)ean and Alnerican areas, ilcluding 7 from Gotland. 3 from England, and 3o from the Xiagaran of America, some of which are prolmbly synonyms. The Alnecan species are distrilmted among the subdivisions of the Xiagaran as follows" Rochester 4, Waldron 7, Racine , Beech River 8, Decatur . The last e are now first de- scribed, one of theln marking a new departure fl-elll the type. The Tennessee collections 36 SMITHSONIAN INSTITUTION from the 13eech River formation and the Waldron shale at Newsom have yielded exception- ally fine material of already known species, some of which I am illustrating with new figures, where the characters are better shown than in the originals. Several of the leading forms are so amply treated in the published accounts that further attention is hot needed. A full list of the species with their references is given in Bassler's Index. This genus is remarkable for the absolute uniformity of its cup plates. In all the numerous species there is scarcely a variation from the number, form and distribution of the plates as above stated. Eucalyptocrinus elrodi S. A. h'Iiller Plate 8, figs. _r, z Eucalyptocrinus elrodi MilIer, 17th Rep. Indiana Dep. GeoI., 189z, p. 650 (adv. sheets, p. 4o), pl. 7, figs. 9, lo.Wachsmuth and Springer, N. A. Crin. Cam., 1897, p. 339, pl. 81, figs. 7a, 8-13.Bassler, ]ibIiogr. Index, 1915, p. 5o3, 5o4. The colonv of the \Valdron shale at Newsom seems to have been particu- larly favorable to the growth of this and the succeeding species, they having attained a size unprecedented in the genus. I figure here two calices far exceed- ing those from the type locality, and in v,hich the pustulose ornament in t',vo styles is wonderfullv sbarp, and the calvx plates are delineated with the clarity of a diagram. Horizon and locality. \Valdron shale, Niagaran; Hartsville and Waldron, Indiana; Newsom, Tennessee. Eucalyptocrinus magnus \Vorthen Plate 8, fig. 3 Eucalyptocrinus magnus Worthen, Geol. Surv. Illinois, 6, 187, p. 5Ol, pl. 25, fig. 3.--Wachsmuth and Springer, N. A. Crin. Cam., 1897, p. 348, pl. 82, figs. 7, 8.--]assler, Bibliogr. Index, I915, p. 5o5. This fire of a cup 75 mm. in diameter is given to show the maximum size that may be attained by the genus. It is hot an isolated example, as the species is typically large, with cup lov, broad and smooth, and specimens are hot uncommon of approximately the dimensions of this. It is abundant in the Waldron beds at Newsom, and a characteristic fossil of them, hot having been found at the Indiana localities, although it is reported from the Racine dolomite of the Chicago area. For the opposite extreme in size reference should be had to E. ovalis, of which some specimens are less than 5 mm. in diameter, and which rarely exceed IO or IZ mm. (see N. A. Crin. Cam., pl. 8z, fig. 4). Horizon and locality. Waldron shale, Niagaran; Newsom, Tennessee. Eucalyptocrinus lindahli \Vachsnmth and Springer Plate 8, figs. 4-5 Eucalyptocrinus lindahli Wachsmuth and Springer, Ara. Geol., 189, p. 139; N. A. Crin. Cam., 1897, p. 347, pl. 82, fig. 9.--VVood, ]ull. 64, U. S. Nat. :Mus., 9o9, p. 47, pi. 12, figs. 5, 6.--Bassler, BibIiogr. Index, 1915, p. 504. A rare species, which was tllkllown to collectors from the tilne of Troost, who exhibited in 1849 what he rightly called a maffnificent specilnen tlnder the CALYPTOCRINIDAE 37 naine Eucalyptocrinus splendidus which remained buried in lais unpublished monograph until 19o9, down to the date of Wachsmuth and Springer's descrip- tion. Only two or three specimens have been found, all remarkably true to type, from v«hich I ara giving figures of a very mature and what may he a young indi- vidual. The depressed interbrachial partitions wholly lack the thickening and wide extension of those of E. milli9ame; instead they are narrow and knife- like, v,ith a peculiar splitting or doubling at the extreme upper end--seen also in E. z'entricosus. Horison and locality. Beech River formation, Niagaran; Wayne and Decatur counties, Tennessee. Eucalyptocrinus milliganae Miller and Gurlev Plate 8, figs. 6-8 Eucalyptocrhms milli9anae, Miller and Gurley, Bull. IO, Illlnois St. Mus., 1896, p. 88, pl. 5, figs. 4-6. Bassler, Bibliogr. Index, 1915, p. 5o5. This is one of the best defined species of the genus, but Millet and Gurley's type specimens were imperfect and failed to show its most distinctive character, the wing-likë projections of the interbrachial partitions, as is seen in the three specimens I have figured, especially fig. 6. These are selected out of a dozen or more crovns ahnost equally perfect, fron a colony in the uppermost shale of C ' the Beech River formation at Tu k s Mill, which bv their prominence gave to that bed the naine Eucalyptocrimts zone. These specimens vary greatly in size, from 2o to 5o mn. in height of crown, but without exception they have lhe pro- jecting partitions more or less indicated by which the species is readilv distin- -uished. This is modified by growth, being lnore pronounced in the older indi- viduals. Along with this character the turbinate calyx, broadly truncate at the base, and the smooth surface, are substantiallv as described, and the median swelling of the arms, narrowing to fine points above, is to le noted : they do hot fold over the tegmen or encroach upon it in anv v,'ay, but the widening parti- tions curve over to a junction with the central parts, formin,e, a broad, fiat cir- cular roof, v«ith all its plates well exposed. This is in marked contrast with E. ventricosus in which the exposed part of the teg-men is reduced to a small disk. Hori:on and localita,. Beech River formation. Eucal3,Ptocrim«s zone, Niagaran- Tuck's lkçill, Decatur County, Tennessee. Eucalyptocrinus ventricosus \Vachslnuth and Springer Plate 8. fi,qs. 9-12 Eucalyptocrinus ventricosus XVachsmuth and Springer, N. A. Crin. Cam., 1897, p. 341, pl. 83, figs. II, I2. Bassler, Bibliogr. Index, I915, p. 507. The most abundant species in the ]eech River formation, being' round at almost all the localities throughout the Tennessee river area, but only at the Tuck's lnill beds bave such finely preserved specimens been recovered as those ,]g SMITHSONIAN INSTITUTION I ara figurine. It is n«)tal)le alwavs f«)r the full rotundity of ce)rite)u1", the arlnS infolding ch,selv, t,ver the mar¢in of the te-lnen, with slightly visille pal-titi,laS, lcavinp_, exposed onlv a small disk in the center, in strong contrast to the wide- spreading ro«,f of E. milligcmae. l;eech River formation, Niagaran" Decatur, \Vayne and Perry Horizon and local#v. counties, Tem]essee. Eucalyptocrinus sp. Platc g. fi'd. I3 \ form from the P, eech River formation, Decatur Comty, Tennessee, with cup once and a hall wider than high, and unusually tumid plates, probably different from the other species. Eucalyptocrinus pernodosus new species Platc O. fiys. r- 4 This species, fr,ln the Ulqerln«st NiaR-aran, stands out distinct fro,in the others lw its extremelv low a(l broad cup, twice a wide as high, relatively en,wlnOUS RR, and the hih convexity of its cup-plates. In mature specilnens, as in figs.  and 2, this oes to the extreme of nodcMtv, the plates beinff mediallv 1)r«),luced illt,) spil«,US projections reselnl)linR" l)effs. The Cl-OWll is unusuallv elonFate, exceeding the longest c)f E. milliganac 1)v o per cent, but this exces- sive lelRth is strictlv in the arms, which are also st«)ut, with little taper, but fi-)ldin-«)ver at the tips )etween the nal"row 1)artitk)ns, which are thus left well expc)sed surrc)unding a relativelv small median disk. This aud lhe forlnS fc)llow- ing are the OlflV exalnl)les of the genus as vet round in this fOl-lnatiola. In con- t«)ur «)f cup the species mav 1)e CC)lnpared with E. dcprcssus of S. A. Millet. froln the Racine dolomite, fiured in N. A. Crin. Cam., pl. 8z. fig. 3- Horison a.d localitv. Decatur limestone, Niagaran: quarries above Perryville, Ten- nessee. Eucalyptocrinus sculptilis new species Platc 9. fig.". 5-6a This companion species, from the saine h,-,riz,n as the last, is the reverse «,f it in most of the characters. Inslead of the lwoad, low cul, it is here of the sul»turlfinate t.vle fre«luent in the ,-enus, .and in place of the striking convex or nodose elevati,-,n ,f thc plates, there is an e«lually strikin.o,q surface marked lw a delicate sculpturing extending from the RR t, the uppermost cup-plates. The singular appearance of the stem shown in fi.. 5 is due to a peculiar spreadin of the lmp_, nodal ossicles, exposin 1)etween them a Rreater number of short internodals. The structure is evidentlv similar to that seen in the Devonian Dolatocriuus, as is fully explained and illustrated in my paper upon that R-enus, CAL YPTOCRI NIDAE 39 lhlll. I 5, U. S. Nat. lus., i)2i, lp. 6-, pis. 9, io. ['l-esunlablv the long runded cohmmals in the stem of tiR. 5 are ncdals siluilarlv overgl-OWil, but with,ut separati,n to exp«,se the intervenin" plates. Horizon and locality. Decatur limestone, Niagaran" Bluffs near Perryville, Tennessee. Eucalyptocrinus Sl). Pl«tc O, figs. 7, 7a A form from the saine h«izcn as the preceding having a perfectly smooth surface and turbinate calyx, which mav l»e a nexv species, l»ut the characters are hot sufficientlv pro- nounced for descril»tion, and there it a little uncertainty as to the number of IBr. Horizon and 16calitv. saine as last. Eucalyptocrinus crassus ] l all ['latc 7, .filS. I0, 20 lç.ucalypto«rinus crassus Hall, Trans. AIbany Inst., 4, 1863, p. 197.assler, ibliogr. Index, I915, p. 503. The most alnmdant American pecie, amlly illustrated ia various l)ublica- ti(ms n()te(1 in the Index. The two fiures arc iven here mçrelv fc)r COml)arison with Gacacrinus in regard to the ventral l)yramid. The structure is further hown in the Camerata m()nogral)h, pl. S, tiRs. )2, 4, Il- Horizon and locality. XValdron shale : the specimeus figured are from Hartsvil!e, lnd]ana, but the species also occurs abundantly at Wahlron, and at Newsom, Telmessee, and is reported frç)m the Racine doh)mite of the Chcago area. CALLICRINUS D'Orbigny Plate 9 Callicrinilcs D'Orbigny, Prodr. Pal.. , 849, p. 45- Callicrim«s Pictet, Traité Pal., -d ed., 4. 1%7, P. 3oL--\Vachsmuth and Springer, Rev. Pal., 3, 885, p. 35; N. A. Crin. Cam., 897, p. 353.Veller, Jour. Geol., 5, 7, P- 774; ull. Chicago Acad. Sci., 4, pt. ooo. p. tT, fig. 47.Bather, Treatise on Zool., 3, 9oo, p. 64. fig. 77.Zittel-Eastman, Textb. Pal., d ed., 913, P. i9.Çomplete reference and list of sp«cies, Bassler, iblingr. Index, 95, p. imilar t [ttcalyptocrintts in the CUl», l)tlt l)asal concavitv uuallv broader ; temen c«,ntracting to a decanter shape, and partitions only extendin part wav to ends of arms" large spin,us processes freluently given ff frolu plates of cup and tegmen, the upper circlet of the latter often extended in four quadrant- shaped horizontal lwojections, sometimes to a considerable length. Gcnotype. Eu.eeniacrinitcs costatus Hisinger. Distribution. Siluriau" Gotland, England, America. This closely allied form, also typically Gotlandian, bas added eight more species to the Calyptocrinid type for that area. besides one or two perhaps undescribed, from England. It also became well established in the American Silurian, where if judged by the number of repoed species it would appear to be one of the leading crinoids, limited, with one exception, to a single formation or its equivalent, the Racine dolomite of the Chicago area, from which nine species have beeu described. A these species are nearlv all based upon internal casts of the calvx, in which some of the characters are O»scure or hot shown at all, there is probably d.O SMITIISONIAN INSTITUTION in this genus, as well as in EucaIyptocriJms, some duplication. The generic relations of the species were at first hot understood, some being described under Eucalyptocri»ms and some as a strange organism called by I-lall C,ptodisct«s, now known to be appendages of the Callicrinus tegmen. Weller was the first to point out this fact, and his studies upon the abundant material of the Cicago area did much toward clarifying out understanding of the American occurrences. Most instructive figures for the explanation of the genus are given by Bather in the Treatise on Zoology (Lankester), 3, I9OO, p. 163. The exceptional species from the Laurel formation described by Wachsmuth and Springer from a single specimen can now be further iIlustrated, and some of its characters better defined. Froln fragments we know that there were other species in the same beds. Callicrinus beach|eri \Vachsmuth and Springer Plate 9, fi9s. 8- 3 Callicrim«s beachlcr Wachsmuth and Springer, Ara. Geol., IO, 1892, p. 14o; N. A. Crin. Cam., 1897, p. 355, pl. 83, figs. I4a, b. The series of figures froln six specilnens here given are especially directed to the surface characters of the dorsal cup, which is ntable for the extremelv high and sharp wavy ridges which traverse the plates from radials to afin-bases. In the type specimen this v«as much obscured by hard lnatrix, but these speci- lnens occurred in a sort gralmlar limestone readily removed bv preparation. The smooth, decanter-shaped pyramid enclosed by the arlns, with the ver', short partitions at the lower mar.o_,-in, are also well shown. Horiaon and locality. Laurel limestone, Niagaran; St. Paul. Indiana. Callicrinu-. sp. Plate 9, figs. _r_l-_r 5 These are the terminal quadrant-shaped plates of the tubular tegmen which abut by fours, with a small anal opening in the middle. First described bv Hall as Cryptodiscus, they have been thoroughly explained by \\relier in Iris paper for the Chicago Academy, and Bather's figures 2, 3 and 4, on page 16 3 of the Lankester Zoology, show how they go together. Horizon and locality. Laurel limestone, St. Paul, Indiana. Callicrinus sp. Plate 9, fig. 6 This is auother of the quadrant plates which were only connected with their fellows by short sutures, and beyond that were produced into greatly elongated, rounded appendages. Doubtless these types represented different species, perhaps some of those described by Weller from the Chicago area, but we have only the franents of this and the preceding form, v,hich are too meagre for comparison of species. Horizon and locality, saine as last. BATOCRINIDAE 41 Falnily ]3ATOCRINIDAE \Vachslnuth and Springer Monocyclic. ]3ase hexagonal. BB 3, equal. Lower brachials and inter- brachials incorporated in dorsal cup; radials in contact except at anal side; proximal anal plate in line with RR, heptagonal, followed by three in second range; ravs usually branching within the cup, and the free arms simple, pin- nulate; first prilnibrach quadrangular except in Periechocrinilme. Oldovician to Carboniferous. Jaekel, Phylogenie und System, I918, p. 34, goes back to the plan of Angelin, and while rejecting Monocyclica and Dicyclica as grand divisions of the crinoids, proposes monocyclic suborders based upon the number of basals" but after listing those of 4 and 5 BB as Tetramera and Pentamera, he throxvs the remainder, whether with 3, 2, or undivided basals, into a single suborder, [iomera. LTnder this he puts together all Batocrinidae and Actinocrinidae into the younger family, Actinocrinidae, a short-lived derivative of the other, on the ground that the distinguishing character between them, viz." that the first has three and the last txvo anals in the second range would scarcelv be suflcient even for separating oene a. In this he completely ignores the ahnost unrivaled constancv of the characters by xvhich these two familles are separated according to the accepted classification. It is now well known that among the crinoids modifications of the anal structures yield characters of the highest taxonolnic value. A character in zoological classification derives its value, as has been repeatedly pointed out by the most eminent authorities, hot from its 1-,hysiological irnportance, but from the uniformity xvith which, however unimportant func- tionally, it prevails throughout manv different species, and is common to a great number of forms and hot common to others. Here the familv Batocrinidae, extending from the Ordo- vician to the later Loxver Carboniferous, with nearly 300 species, distributed among -'24 genera which differ alnong themselves bv many striking and conspicuous features, is held together by a definite structure of the anal area, xvithout the slightest deviation save an occasional sporadic specimen. A perfectly evident transitional genus leads to the Actinocrinidae, the character of which is equally constant and invariable in over oo species, and 7 thoroughly well defined genera, No one looking at a complete collection exhibiting tle entire assemblage of genera and species under these txvo forms, or at the ample illustrations of them as given in the Camerata monograph, will doubt for a moment that the far-reaching characters by xvhich they are defined mark the lines of descent. For an author of a systematic work to say that they xvould hardlv serve {or separating genera, is pure dogmatic assertion, ruade xvithout the slightest consideration of the facts. Subfamily CARPOCRININAE ]3ather ]3]3 3; RR rather large; I]3r quadrangular; IIBr usually passing into the free arms, mostly 2, occasionally 3, 4, or 5 to the ray; iBr definitely arranged; anal plates in vertical row; tegmel composed of numerous small plates, with orals in the center compressed : column round. .Jr2 SMITIISONIAN INSTITUTION" CARPOCRINUS  Iiiller Plate 7 Carpocrinzts Millier, Monatsb. Berlin Acad. Wiss., I, 1848, p. 208; \crh. Naturh. \ erein, Iz, I855, P- I9--- Wachsmuth and Springer, Rev. Pal.. z, i88I, p. o5 (full synonymy, pp. o7, Jo8).--Bather, Treatise on Zool., 3, I9oo, p. iOS.--ZitteI-Eastman, Textb. Pal., ;d ed., I913, p. I94.--Jaekel, Phylogenie und System, I918, p. 37. Phoenicocrmuts Austin, Ann. Mag. Nat. Itist., II, 843, p. zoS.--.lbracrinus D'Orbigny, Prodr. Pal., 185o, p. 47.--Habrocrimts Angelin, Icon. Crin. Succc., 1878, p. 3; Pionocrinus Ang., ibid., p. 4; Lcpto- cri»nos Ang., ibid., p. 3. Calvx rotund with protul»eralt lmse; iBr usuallv in several ran-es; anals in 1rcmlinellt ridge : arms st«,ut, nct over tWo to the ray,  ith brachials uniserial, quadrangular or slightly cuneate, l»earing a pinnule on each side, s(,metimes two at the longer face. Genol3,]e. ,4ctinocrinites sim]@.r l'hillips. Distribution. Silurian; Gotland. England, America. This genus, treated tmder several names, is one of the most prolific of the north Euro- pean Silurian, frm which no less than nineteen species have been described, all occurring in Gotland. and at least one also in England. A full list is given bv \Vachsnmth and Springer, Rev. Pal., 2, pp. o7-8. Representing as it does an earlv and simple Batocrinid type, some migrational extension into the American Silurian might well be expected, and in fact was looked for with confidence as the Niagaran fauna of Indiana and Tennessee began to shoxv its remarkable development: So far this expectation has been realized by onlv a single species, which is believed to be fully characteristic as judged by the calyx alone. For comparison, and to illustrate the accompanying type of arms with their doubled pinnules, [ ara figuring on plate 7 a complete crown of C simpL'.r, the species which is common to Egland and Gotland. Carpocrinus sculptus new species Plate 7, figs. _" t-_'«b F.xcept fc, r the absence of arnls, tle sl»ecimen is very perfect, the calvx being entirelv free including the tegmen • even «,f the arms there are short stumps in one rav. enough to show that they hax e the ntmflel-, stoutness and uniserial brachials characteristic of the genus. The calvx is well rounded, with protuber- ant base, prçporti«mally more elongate and with m,re ranges of iBr than usual. ledian row of anal plates very consl)iCU«Us , passing up int« the tegnen to an opening midwav fr«m the center and next to the p«,sterior çral, bordered bv a circlet of small convex plate.a. Tegnen str«,ngly marked l»y 5 very distinct orals. 4 small partly enclsing the much larger p,sterior me, and extremelv conspicu- ous ambulacra with a double series of c«,vering plates, passing outward and l»ranching to the o arm-opelfings" ilteralnl»tlacra small and numerous. Surface of cup plates very çrnatelv sculptured" this is sharp and distinct cm the part which was imledde(1 in the sort matrix, fig.  , lmt in fig. ea. owing to erosion. the surface appears perfectlv Snlooth. Two of Angelin's species, Habrocrims or«tissiuurs and H. oratus, have a similar orna- mentation, but are otherwise different. Hori=on and lo««litv. I,aurel limestone. Xiagaran- St. Paul. lndiana. BATOCRINIDAE 43 DESMIDOCRINUS Angelin Plate î Dc«midocrinus Angelin, Icon. Crin. Suecc., 878, p. 5.Vachsmuth and Springer, Rev. Pal., 2, 88, p. m8.--Bather, Treatise on Zool., 3, 9oo, p. 66.--Zittel-Eastman, 2d ed., I93, P. 94.--Jaekel, Phylogenie und System, I98, p. 37- Calvx as in CarpocriuuÆ. but with iI;r few, anals hot in promhmnt row, arms irregular, 3, 4, «,r perhal»s 5, t the rav, uniserial ; brachials quadrangular. Gcnotypc. D«smidocrim«s pentadactylus Angelin. Distribution. Silurian ; Gotland. England, America. Desmidocrinus laurelianus new species Plate 7, figs. 24-24h This and the succeedin..q- species are referred to the ab,,ve Gc, tlandian enus lecause of the increase ,-,f arms alpe, ve no. and the smaller iBr areas, t tere the latter consist chiefly c,f a sine-le lal"e plate. 111 bolh the anal interradius is fullv developed, but not in the f,)l-ln of a raised vertical row as in Crpocri, us. Ill this the rav hralches on the second llP, r. Çup plates are cc, nvex and smooth. Horizon and locality. Imurel limestone, Niagaran: St. Paul, lndiana. Desmidocrinus dubius new species Plate 7. fig. 25 l)istinguished fro,in the l»l-ecedin " bv the ln,de of al-ln-l»ranchi_, which here occurs first Oll alout the sixth II Fit. alld lel'hal)s a..qain (ll ¢-,lle l-alllUS, thus iving 4 or 5 arms t, lhe rav. The calvx is me, re el,,ngate and CUl» more tur- binate, and the reference tn the Renus is ruade with some d-ubt. ltori:ot and locality, saine as last. Cylicocrinus canaliculatus S..\. Miller Plate 7, figs. 26-20 Çylicocrimts canaliculatus Miller, Sth Ann. Rep. Indiana Dep. Geol., 894. p. 285 (adv. sheets, 892. p. 3), pl. 5, figs. 3, 4.--As Barrandcocrinus. ¥achsmuth and Springer, N. A. Cin. Cm., 897. pp. 484. 485.--Bather, Treatise on Zool., 3, 9oo, p. t66.--Zittel-Eastman, Textb. Pal., 2d ed., tgt3, P. g5--- Bassler, Bibliogr. Index, 95, P. o. The mystery surrounding the relations of the genus founded upon this species as type has hot been solved bv anv of the recently acquired material, bv which our information is still limited to the dorsal cu l) below the arm-bases; it remains insufficientlv known for a generic definition. It has the calvx of the Batocrininae, similar in all visilfle respects to that of the Swedish BarrandcocrinltS with the recumbent arms--a similarity which led \Vachsmuth and Springer to think it might possilfly belon¢ to that genus. The specimens I have since obtained show a thin, flange-like projection at the base which seem to me inconsistent with the close enveloping of the cu l, by the pendent arms such as is indicated bv the various figures of Barrandcocrimts. for example in mv recent paper on Unusual Forms of Fossil Crinoids, ['roc. U. S. Nat. Ius., 67, 1926, pl. 9. figs. 6- 7. Horicmt and locality. Laurel limestone. Niagaran : St. Parti, Indiana. 44 SMITHSONIAN INSTITUTION Cylicocrinus spinosus ne\v species Plate 7, figs. 3 o. 3oa Founded upon an isolated hexagonal base with prominent spinose projec¢ tions, differing thus from all the other specimens. [av be only a variant of the type. Horiou and local#y, same as last. Subfamily PERIECHOCRININAE Barber BB 3- IBr hexagonal ; iBr numerous, passing into iAmb ; tegmen composed of numerous small undifferentiated plates. PERIECHOCRINUS Austin Plate Perlcchocrinitcs Austin Ann. Mag. Nat. Hist., Io, I842, p. o9. Periechocrlnus McCoy, Syn. British Foss., x855, P. 56. \Vachsmuth and Springer, Rev. Pal., 2, p. 27 (list of species) : N. A. Crin. Cam., 897, p. 59.--Bather, Treatise on Zool., 3, 9oo, pp. 66, x68. Zittel-Eastman, Textb. Pal.. 2d ed., I93, p. I94.--Jaekel, Phylogenie und System, 98, P. 35--- Bassler, Bibliogr. Index, 95, PP- 953, 954 (references, synonyms and list of American species). Calyx elongate, slender, expanding to the arm-bases; cup-plates long and rhin, with prominent axial folds along radial series; rays bifurcate two or three times within the cup, leading to from 20 to 40 free arms, biserial, and usually hot branching after beconfing free. Genotype. Actinoo'inites monili.oruds Phiilips. Distribution. Silurian: GotIand, EngIand, America. Of the large number of Siluriav_ species which have been referred fo this genus, at least one is from England, 9 are from Gotland. and  froln North America. The latter are dis- tributed as follows : Rochester shale, I ; Laurel limestone, 2 ; Waldron shale, I ; Brownsport. 3 : Racine dolomite, 4. Besides these are two froln the Lower Carboniferous. and one in Europe from the Devonian which may go better under Saccocrimts. The typical form, as represented bv the abundant and well known English species. P. moniliformis, is well marked and readilv distinguished by the extremely elongate, slender cup, thin plates, unusually high RR and IBr with their conspicuous axial folds running to the arm-bases. Several species of that type have also been described from America, but along with them are some others which while having the saine general calvx arrangement are want- ing in the above characters, having the cup-plates lower, thicker, more convex and Mthout folds. Taking as an example of this type such a form as the Carboniferous P. wl,;tei, pictured in N. A. Crin. Cam.. pl. 6, fig. . one is impressed with the force of the doubt vith vhich it is listed. In the Zittel-Eastman Textbook, edition of 93, 1 undertook to revive Hall's dis- carded genus çaccocrimzs as a receptacle for some of these non-characteristic species, and am making the distinction accordingIy here for two species. An entirely new form for the Tennessee Silurian turned up in the Beech River formation, cIearIy belonging to the English and Swedish type, but unfortunatelv too nmch iniured for a specific definition. BATOCRI N [DAE 45 Periechocrinus tennesseensls (Hall) Plate zo, figs. z- 4 Saccocrlnus temesseensls Hall, Geol. Surv. Ohio, Pal., 2, 875, p. 25, pl. 6, fig. IO.--Periechocrinus termes scensis, Wachsmuth and Springer, N. A. Crin. Cam., I897, p. 528, pl. 5o, fig. 4 (figùred as Roemer's type of Saccocrlnus speciosus).--Wood, Bull. 64, U. S. Nat. Mus., 9o9, pp. 76, 78, pl. 6, fig. o.-- Saccocrinus speciosus Roemer (not Hall), Sil. Fauna Westl. Tennessee, 86o, p. 42, pl. 3, figs. 3a-c.-- ]3assler, ]3ibliogr. Index, 915, P. 956. The species is well known to collectors in the Tennessee area from the earliest times. Both Troost and Roemer recognized it, and in the modern col- lections it is hot uncommon. It is rather on the border liue between the two allied genera as they are here defined. I ara figuring four specimens in order to show sonle of the minor variations which must be considered in anv critical comparison of the described species. ollle show the axial folds by obscure traces, and some scarcely at ail; but all have the slender calvx and narroxv tur- binate base usuallv seen in the genus. The arms varv lu different individuals hot otherwise distinguishable, from 4 to 5 to the rav. The species has beel round at the priucipal localities of the Brownsport group. Horigon and locality. Beech River and perhaps other formations of the Brownsport, Niagaran ; Decatur, Perry and Wayne counties, Tennessee. Periechocrinus sp. Plate zo, figs. 5, Sa The crushed and damaged specilnen here fiured is of a distinctly different type from the preceding, and has much the character of the typical English form: it is the onlv one thus far round that seems to approach the European type so closely; if in better condition for observation it would doubtless bear close comparison with some of those species. The calyx walls are very thin, and the axial folds leading to the arms sharp and prominent. In the number of the branching, biserial arms, which seem to run to 7 or 8 to the ray, the specimen shows a significant resemblance to Angelin's figures of P. moniliformis, Icon. Crin., pl. 9, figs. 4, 4b. Horizon and locality. ]3eech River formation, Niagaran ; Decatur County, Tennessee. SACCOCRINUS Hall Platc zo Saccocrlnus Hall, Pal. New York, 2, 852, p. 2o5: 28th Rep. New York St. Mus., 879, p. I27. Roemer, Sil. Fauna Westl. Tennessee, I86O, p. 44.--Meek and Worthen, Geol. Surv. Illinois, 3, 868, p. 347; ibid., 5, 873, p. 394---Zittel-Eastman, Textb. Pal., 2d ed., 93, P. 94.--13assler, ]3ibliogr. Index, 95, P- 954. Calyx arranged like Periechocrinus. but the arms from about 20 (excep- tionally o) openings branch after becoming free, and are biserial botb below and above the bifurcations. Plates usuallv thicker and more convex, and with- out axial folds. 4 46 SM ITHSONI-\N INSTITUTI()N Genotype. Saccocrimts spcciosus Hall. Dislribution. Silurian. Devonian and Lower Çarboniferous. America, lïurope. One of the Gotlandian species, P. lacz,is (Ang. hot Portlock)=P. ninor \Vachsmuth and Springer, Icon. Crin., pl. 18, fig.  , differs from the dominant type in a way that would lead toward this genus. The Carboniferous species belote alludcd to would be nmch more at home in this restricted company, and thê larger genus will be 1)etter balanced and lnore consistent in its characters with such forms as the first one hêre recorded eliminated. Saccocrinus benedicti S. A. 5Iiller Plate IO, fis. 6-Il Saccocrlnus benedicti, Miller, 7th Ann. Rep. Indiana Dep. Geol., I892, p. 283 (adv. sheets, p. 29), pl. 5, fig. I.--Periechocrh, us ornatus, Wachsmuth and Springer, N. A. Crin. Cam., I897, pl. 5, fig- 7 (hot pl. 5o, figs. 3a, b). A stronly" marked species, almndant at St. l'aul and obtained in excellet preservation lnilms the alms. The contrast letween it and P. tcntesscetsi« figured on the saine plate is most Stl-ikinK. There is a stout, ovoid calvx, with rather 1)l-oad base, thick plates of which the surface varies froln silnple convex to rugose, ne,dose, and even perhaI»s stellate ornament. The al-m-cq)elings stand out boldlv fl-om the calvx at al)crut the third III;r, thus lilniting the free arms to two to the rav: how they bl-anch, if they da, bevond that is unkla,wn. In riais slnall numl»er of arlns the species diffel-s widelv froln all cthers of the genus thus far known. The crue specilnen with stellate Ol-lamentation, fig. 14, is l)rob- allv of a different species, but lacks t lnuch in the arm l-egion for definition. Horizon a»d locality, kaurel limestone, Niagaran : St. Paul, Indiana. Saccocrinus cuspidatus new species Plate IO, ff(q. I fi A form partakin K more of the general shape of Pcriechocriuus than the preceding, but with a less slender, far larger and more robust calvx; wb_ile the shorter cup-plates with their sharp cusps instead of folds diffel-entiate it COln- pletely, and the latter character fr«,m all other species otherwise associated. The arms apparently lecome free with the III P,r. which would give an average of four to the rav, lmbably subjcct w variatim. The specimen is from a higher formation than the others mentioned. Horizon. and locality. Louisville limestone, Xia.e,aran : .[efferson County, Kentuckv. In the Laurel limestone at St. Paul. there is another large species, ill defined, described by Miller and Gurley as 5"accocrimzs umbrosus. Bull. 6, Illinois St. 5Ius., 895, p. 24. pl. 2, figs. 13, I4. Sul»falnih-I;.-T(')CI X INAE Temen lwcad, well diffelentiated. )lates large and heavy, fOllning a riid roof; arms n(,t lwanchin 1)evond the CUl): lfisel-ial ; fil-St IBr u.uallv quadlanKu- lat. Silurian to l.(,wer Çarl3«mifelCus. BATOCRINIDAE 47 This extensive subfalnily, typicall.v Carboniferous, and hitherto considered as having originated in the Devonian, nmst now be lnoved a step farther back in the geological scale and credited to the terminal Silurian, as is proved by the occurrence of a weil defined species in the Tennessee area. Aorocrinus nodosus new species Platc o, fi.qs, ±6-±6b Clvx rotund, with slightly l»rotubcrant be; 1)lates elevated into sharp no(les: iBr few, hOt c«mnecting with tegmen except at the anal side. Anus sui»- central withat a tube. Tegmen plates SlnOth, and none of them spiniferous. The single specimel upon which this species is based was round in the uppermost forma- tion of the Tennessee Niagaran, the Decatur limestone, in a bed which is closdv associated with the overlying I.inden with its characteristic Helderbergian species of the Devonian çcvphocrinus. Xevertheless the presence in the saine laver of such an unquestionable Nia- garan form as Carvocr[nus orua.tus leaves no roo«n for doul,ting the stratigraphic position of our species, which is thus in accord with the great difference in its racles from that of the hitherto known Devonian forms. The extremely rotund and robust calvx and sharply nodose cup-plates produce a distinctlv new type. for which, however, we may bave a connecting link in a species from the Hamilton recently acquired, and herewith figured. It has been contended that the genus, torocrinus as fotmded lw Wachsnmth and Springer, N. A. Crin. Cana., I897, p. 470. should give wav to Coclocrinus of 5Ieek and Vorthen. kVhile this nmv be true for SOlne Lower Carboniferous species, that genus was founded upon a type with verv broad, concave base, from which most of the f.rms referred to ,4orocr[ntts are sufficiently differentiated, but which mav also have a forerunner in the new Devonian species here figured. Hori:on and locality. Decatur limestone, Niagaran: below Grandview. o mlles above Clifton on the Tennessee River, Perry County, Telmessee. Assoeiated with Mariacrinus rotundus. Aorocrinus clarkensis new species Plate Io, figs. r7, r7a This isolated specimen from the Devonian is figured for comparison with the preceding species. Whether it belongs to this genus is hot clear, in the ah- sence of the parts in the afin-zone, h is derived fr«,m the Hamilton leds of Clark Çountv, lndiana. 48 SMITHSONIAN INSTITUTION Familv PLATYCRINIDAE Roemer 3[onocvclic. RR in contact all around. No anal. ]3B 3, unequal, forming a pentagon. This monocyclic family is intermediate between the typical Camerata and the Inadunata. As in the latter, the dorsal cup consists chiefly of basal and radial structures, those of inter- radial origin being in the Iater stages largely confined to the tegmen. It had a long geological range, from Silurian to Lower Carboniferous, and in the latter its typical fonns were fully developed, in which the plates above the radials enter but slightly into the cup, and the stem becomes remarkably specialized with an elliptical section and transverse ridge. It cuhninated with a great number of characteristic species, in which the dominant characters mav be seen and studied to best advantage. The Silurian and Devonian stage exhibits some marked variations, but in the main embraces forms of the simpler and more primitive types, showing the Ieast departure from the Camerate plm. .Vhile they are for the most part rare, the prescrit collections bave yielded abundant representatives of two of the subdivisions. In each the material is of exceptional importance, because the specimens belonging to some forms occur in such numbers and preservation as to afford the means of comparative studies hot hitherto possessed on either continent, requiring in one case the recognition of a new genus. Section I. Subfamilv COCCOCRININAE Bather Ravs with two or more primibrachs. The division here first discussed, embracing forms with 2 or more IBr, represents the simplest form of the Camerata, the calyx consisting only of 3 BB forming a pentagon, 5 RR, 2 x 5 IBr, 5 iBr and 5 orals. The tegmen is ahnost completely occupied bv 5 large triangular orals forming a closed pyramid analogous to the lard-al stage of the crinids. Anal opening is lateral, in the interradio-oral suture, and the arms usuallv two to the ray. Column round, no sign of the elliptic columnals having yet appeared. LYONICRINUS new genus Plate   Pro Coccocrims bacca Roemer, Sil. Fauna Westl. Tennessee, 86o, p. 5L--Cf. Coccocrinus Joh. Mailler, in Wirtgen und Zeiler, Verh. Naturh. Verein Rheinl., 2, 855, p. o.Zittel, Handb. Pal., , 879, p. 347.--Wachsmuth and Springer, Rev. Pal., pt. , 88, p. 58; pt. 3, t885, p. r4; N. A. Crin. Cam., t897, p. 738.--Bather, Treatise on Zool., pt. 3, 9oo, p. 56.Jaekel, Krinoid. DeutschI., 895, P. 95; Phylogenie und System, 98, p. 9L--Zittel-Eastrnan Textb. Pal., x93, P. x99.Bassler, Bihliogr. Index, 95, P. 248. Dorsal cup as in the Platycrinidae. Small basal in left posterior position. ]Br 2. IIBr mol-e than 2. Tegmen composed of 4 large, triangular interambu- lacral plates (? orals) surrounding a central space, perhaps for posterior oral, with open clefts between them for amlmlacra; plns one large posterior plate f]anked by  smaller ones supporting a protulerant anal opening. Arms tell, unbranched, nniserial, v,'ith quadrangular brachials. Genolype. Coccocrims bacca Roemer. Distribution. Silurian; America. This genus is founded upon the species Çoccocrims l, acca. Roelner, of the Telmessee Silurian. Much has been written about the genus Coccocrims, and it still remains illy under- PLATYCRINIDAE 49 stood, partly owing to scarcity of material, and partly to the inherent obscurity of all the early Platycrinidae because the dorsal cup is so simple and alike in so many genera. It has been shifted about in classification ; but most of the later authorities agree in placing it among the Platycrinidae along with Culicocrimts. From this Jaekel in lais worl on Phylogenie und System, I918, dissents, and while placing Culicocrimts among the Platycrinidae greatly re- stricted, transfers Coccocrimts to an entirelv different order, and ranks it in a suborder Hvocrinites al.ong x-ith Iesozoic and Recent forms such as Eudcsicrimts, Hyocrimts, lPtilo- -crimts, etc. The typical species, C. rosacezts, described bv Roemer in I844 as Plat3,cr[mts , vas ruade bv Johannes lIiller the type of Coccocrimts in 855. It has a tegmen constructed mainly of rive large triangular plates, interlocling and forming a pyrarnid somevhat resembling that of Haplocrizzus, hax-ing grooves along their edges: but with this difference, that vhereas in Haplocrimts the x'entral pyrarnid tests directly upon the shoulders of the radials, in Coccocrimts there is a set of plates interposed called " suborals," interbraclial in position, on which the trianflar plates rest in direct succession. The anus is at the line of junction between the posterior interbrachial and the triangular plate, each being notched for the opening. The structure is vell shoxvn by fiires  and 2 on plate . the first being from vhat is probably the original of Schultze's figure in lais monograph of the Eifel iEchinoderms, and the last from the specimen figured by \Vachsmuth and Springer in the Camerata monograph, pl. 3. fig- 4, obtained bv me at Gerolstein in 887. There is a slight difference in the contour of the tegmen of the two specimens, and in the appearance of the grooves, partly due to differ- ence in preservationthe last bein somewhat crushed--but the essentials are the saine. It is a [iddle Devonian species. The nearest allied form to Coccocrimt.s i,; Czdico,rimts, d'escribed bv Johannes lIfiller from the I.ower Devonian, xvhich bas likewise a tegmen composed of 5 large orals,,but thev are closely united bv suture, without anv groove along their edges : thev are also preceded bv plates interbrachial in position (pl. . figs. 3. 3a, 4, 4a. b. c). The chier difference between the two genera, so far as can be ascertained from the material available, is said to be that Culicocrizus has heavy, biserial arms. while in Coccocrimts, the arms are supposed to be uni- serial and rather delicate, and that the former has the lower brachials more deeply incor- porated in the cup than the latter. The tegmen of ('ttlicocrintts is paralleled bv that of M'rtillocrimts Hall, from the Onon- daga of New York, in being composed of closelv interlocking oral plates, bt without any underlying interbrachial structures (pl. x, figs. 5, 5a) • In 86o F. Roemer described the species Coccocriztus bacca, from the Silurian of Ten- nessee. It was a rare form, and he had but fev specimens, vhich disclosed nothing of the tegmen; but he saw the beginning of the interambulacral plates, which he and subsequent authors took to be the " suborals " as in C. rosaces. Little addition to his knowledge was obtained bv later collectors, \Vachsnmth in lais Tennessee excursions finding but four speci- mens, one of vhich preserved some of those plates, but hot intact. This vas figured in the Camerata rnonograph, pl. 75, figs. 5a-. It has been assumed that the interbrachiallv situated plates here. as in Coccocrimts, were followed bv a pyramid of trîangular plates substantially covering the ventral side. 5Iuch of the discussions of the generic position of Coccocrimti hitherto has been based on this species, noxv here separated. Among the collections ruade for me in Tennessee in 9o6- 7 is an extraordinary lot of rnaterial of this species from vhich considerable nexv information has been derived. There are in ail about ,ooo specimens, from tvo colonies hot far al)art. They occurred mostly in a shalv and limestone deposit disintegrating into clay, forming part of the lower member of the Beech River formation designated by Pate and P, assler as the Coccocrimts zone. The specimens chiefly consisted of the calx'x only, but a few were round with more or less of the arlns attached, uniserial, and ten in number. Iany of the specimens ha-e the interambulacral 5o SM ITIISONIAN INSTITUTION tegmeu plates tu gooE1 coudition, together with some additional structures connected with the anus. aud traces of aml)ulacra. In uumerous examples the base is well exposed, so tbat the positiou of the small basal can be observed. Jaekel and l,ather bave stated that this is n«,t a reliable character for the genus, and _laekel declares it is hot constant in C. bacca. These specimeus show that it is thorouglaly constant for the species, but that its position is hot in accordance with lhe general rule in crinoids with an unequallv, tripartite, monocyclic base, namely, left anterior (or 7 o'clock). ¢3u the contrary it is here uniformlv at the left postericw ( o o'clock, pl. r t, figs. 8, -t, _-e2), whereas in C. rosacctts, as shown bv my specimens, it is normal. The former alpears t, be the case in the specimen figured in the Camerata mongraIh, pl. 75, fiffs, i Sa-c: but through misunderstanding a n»te was inserted in the expla:ation of fiff. Sa statinff that it is drawn with the anal side at the left lower corner (.vhich would naake it according to rule), whereas it is actuallv at the right lower corner. Fig. c, the l)osterior view, shows this by the position of the interhasal suture, which wouhl be to the right of the interradial suture if the explanation was correct. _N,'ov the tegmen of C. bacca appears to be consideral»Iv different from that of the typical C. rosaccus. ]nstead of leing suboral plates succeeded bv the large triangular plates, as in that species, and as heretofore suppsed tu this. the interamhulacrals are themselves almost tri- angular, the lower face «,btuselv angular to fit directlv into the notch formed 1)y the sloping shoulders of the radials, while al)ove they are extended to an acute angle, so that when normal position thev would form a low pyramid, lq, ut instead of interlocking at the ai)ex thev leave a considerable open spacc in the middle, and are also hot in contact laterally, but are parted by open clefts running between their edges to the arm bases, along which traces of side pieces of ambulacra can occasionally be seen (pl. ] t. figs. 6 to 8). The larffe tegmen plates are analogous in position to orals, and that is prol)ab!y the lwoper terre for them. Four of them are of like shape and size. 1,rit the fifth remains to be accounted for. The central vacant space seen in ail the specimens is of the proper size aud position to l,,dge the posterior oral, pushed in between the other four by the anal structures, as in the tegmen of manv Camerata illustrated bv Vt'achsnmth and Springer on plate 3 of their monograph, and precisely as seen in that of Culicocrimts lgured herein on plate  I. figure 4c. It is evident that this tegmen was of rather fragile construction, as the ceutral plate is iu- variablv wanting, and the ambulacra only represeuted by traces. Thus the tegminal structure differs also from that of Haplocrimts and Cu[icocritus. in the fact that the plates of the ven- tral pyramid in those genera are closelv joined, those of Culicocritus without anv grooves, and those of tlal, locrimts with snperficial grooves at their edges, hot for ambulacra, but as mere receptacles for the arms, as herein now shown for the first time in I-t. mespili[ormis (pl. 25, figs. 28, 29. 29a. See abo Devonian Crinoid of N'exv York, pl. 4o, figs. o-I4. There is also a verv material difference tu the anal structure of the two forms. Coccocritttts there is a simple openin- at thc base of the posteri,r oral. In C. bacca, the anus is at the end of a short protuberauce, of which we oft, en find one plate, and sometimes one or two more succeeding it. in llace above a large posterior plate flanked bv a smalIer plate at either side. In one specilne_ font »lates in this sertes are visible, leadinff to the opeuing. The two flanking plates served as a strong sui»port, for we frequently see them. and the inter- vening posterior plate standing firmly upright, while all other plates of the tegnfiual arch have fallen down ('pl.  , figs. IO-2O). The evidence is conaplete to prove that the structure of C bacct is different frona that of C rosacetts in three major characters, riz. : the composition of the tegmen, the anal struc- ture, and the position of the small basal. From this it follows that thev cannot be retained in the saine genus. ,ccordingly I ara l»roposing for the Tennessee species the nexv genus L3'odcrimts, tu memorv of Cool. Sidnev ._"3. I.yon. who was an ardent student of the crinoids, and atlthor of Inauv notable genera and species from the I'entucky-lndiana area. PLATYCRI N 1 I)AE Lyonicrinus bacca (Roemer) Plate l l, fgS. 6-_ 3 Coccooimts barre F. Roemer, Sil. Fauna \Vestl. Tennessee, I86O, p. SI, pl. 4, figs. 5a-c.--\Vachsmuth and Springer, N. A. Crin. Cam., 1897, p. 739, pl. 75, fig- 5.--Wood, Bull. 64, U. S. Nat. Mus., I9O9, p. -09, pl. 4, figs. o.--Bassler, Bibliogr. Index, 915, p. ;48. The species is sufficientlv discussed in the remarks upon the genus. Horizon and localitv. Coccocrim«s zone of lleech River formation, Brownsport group, Xiagaran : Decatur and Perrv counties, Tennessee. Coccocrlnus rosaceus (F. Roemer) Plate r. fi9s. . ra. b; 2 Platycrim«s rosaccus Roemer, Rhein. Ueberg, 844, P. 63, pl. 3, fig. 3.--Coccocrinus rosaceus Job. Mfiller, Verh. Naturh. Verein Rheinl. I:, I855, p. _I, pl. 7, figs. 5a-c.--Schultze, Echin. Eifl. Kalk., 867, p. 89, pl. i2, fig. I3.--Wachsmuth and Springer, N. A. Crin. Cam., I897, pl. 3, fig- 4. For comparison with L3'onicrinus l,acca. Iiddle Devonian : Eifel, Germany. Culicocrinus nodosus (Wirtgen and Zeiler) Plate . ficds. 3.3a Platycrinus nodosus \Virtgen and Zeiler, Verh. Xaturh. Verein Rheinl. i2, I855, p. 5, pl. 6, figs. 3.-- Culicocrinus nodosus Job. Mfiller, ibid., p. -'4, pl. 8, figs. I-4. See discussion under L3,onicrim«s. Lower Devonian : Çol,lentz, Germany. (?) Culicocrinus spinosus new species l'late I I, fi9S. JE' 4 a-c This naine is given to a solitarv specimen from Tennessee, xxith much doubt as t« its generic affinities, but chieflv on accc,unt of the rive large spinifer- ous interlockin,e, orals, which differ fr«,m those of the typical species in having the posterir plate flanked ou the outer side bv anal structures and smaller lateral plates, but nevertheless present considerable similarity in proportion and general arrangement. The 1)rimibrachs are also less deeply incorporated in the cup. Beech River formation, l;rownsport group. Xiagaran; Decatur County, Tennessee. Platycrinidae indet., :No.  Plat« ±z. figs. 2 4. e_/a, b A dorsal cup with massive l)late, and large BB. Beech ]ïiver formation " Decatur County, Tennessee. Platycrinidae indet., No. - Plate ±r. ficd. 25 Calyx with large interambulacral plates in position. Laurel limestone" St. Paul. Indiana. 52 SMITHSONIAX INSTITUTION Platycrinidae indet., No. 3 Plate , figs. 26, 27, 28, 29 A small species rather common lu the Laurel limestone at St. Paul, Indiana. The three foregoing species are figured in order to preserve a record of their occurrence, hoping that future discoveries may throw more light upon them. Hapalocrinus Jackel emend. Barber Plates II, 12 Hapalocrinus Jaekel, Krin. Deutschl., I895, p. 37.--Bather, Geol. Mag., 4, I897, p. 342; Treatise on Zool., 3, I9oo, p. I56. Platycrinidae with 2 or more [Dr; orals small; arms uniserial with cuneate brachials tending to biserial, branching once or twice; column large, bearing strong cirri. Genotype. Hapalocrinus clwans Jaekel. Distribution. Silurian to Lower Devonian; England, Gotland, Germany, America. The specimens which I have referred to this genus are notable for their profuse develop- ment of arms and pinnules, and of strong cirri occurring in definite whorls, at intervals ex- tending apparently the full length of the cclumn. The generic characters of these forms are not very certain. Some of them might perhaps better be placed under Cordylocrimts of Angelin, but the distinctions are hard to point out with confidence, and I have chosen the easier course by throwing them all under the one fonn, which is strongly typified by the "' .Platycrinus '" retiariu.s PhiIlips of the English Silurian. This arrangement would seem to include both uniserial and biserial arms--a variation that may occur among the later Platy- crinidae within the saine species, or even the saine individual, incident to growth, as seen for exatnple in P. huntsvillae. A very strongly marked species from the Lower Devonian is figured for comparison. Hapalocrinus gracilis new species Plate _r_r. figs. 30, 3-r, : With heavy cuneate arms and strong pinlmles, and plates. rather high tegmen Hapalocrinus cirrifer new species Plate _r2, fis. r, 2, 3, 4 Remarkable for the long, slender arlns, in some specimens ahnost thread- like; the calvx is large, bnt details of its structure are obscure. Hapalocrinus pinnulatus nmv species Plate r_,. fiç. 5 Calvx narrow and relativelv smaller, but bearing nmch stronger arlns and pinnules. PLA rYCRIN [D_\E 53 Hapalocrinus tuberculatus new species Plate _r2, fig. 6 Arms and pinnules similar to the preceding, but calv-,= rotund, and with tubercular surface. Hapalocrinus tennesseensis new species Crown much displaced, brachials. Plate , fig. 7 :ith sharply uniserial arms and quadrandar Ail the foregoing rive species from the Beech River formation, Brownsport grcup, Nia- garan: Decatur County, Tennessee. Hapalocrinus devonicus new species Plate 12, fi7. 8 Unusually strong stem and cirri, large calyx, and tubercular surface. Kevser formation, Helderbergian, Lower Devonian ; Keyser, West Virginia. Brahmacrinus elongatus new species Plate 12, fiçs. 9-15 The genus to which this species is referred was proposed bv Sollas, 1 to receive a Platvcrinid form frona the 13ritish Lower Carboniferous of true Camerate type, having the lower brachials completely incorporated in the cup bv means of solid interbrachials. Some of the earlier American species of simi- lar type, such as P. cricnsis. - might wetl be placed under it. and it affords a prac-, ticable resting place fol- the present singularly distinct forln. It mav be defined as a Platvcrinid with large I13r and II13r incorporated in the cup bv i13r in two ranges, huge 1313. and relatively smaller RR than in Platvcrinns. Mong with this it is remarkable for having the base divided iuto 3 subequal plates, which are sharply excavate into a saucer-shaped depression surrounding a rather small stem. This bas a minute axial opening, which is a Platvcrinid characteristic, but there is no sign of elliptic columnals. The pecu- liar excavate base is seen in sex-eral species of Platvcrinus--such as P. hmtts- 'illae and others shown in N. A. Crin. Cam.. pl. îo. fig, 12- pl. 73. figs. I I, 12. In the present species the elongate, rather cylindrical, form of the calyx is different from that of the l:'latvcrinidae generally', as is also the great size of the basals. Apparently there are two arms to the ray, which probably branch again. There are two good specimens of the calyx, and several bases. Horizon and locality. Laurel limestone, Niagaran; St. Paul, Indiana. 1 Quart. Jour. Geol. Soc. London, 56. I9oo, p. -264, pl. I6, figs. I, . - N. A. Crin. Cam., 897, p. 676. See also as to the British form, p. 644. _.1. SMITIISONIAN INSTITUTI)N INSERTAE SEI)IS Nyctocrinus magnituBus new genus an«l species Plate .r2. fi.]s. O-2t .111011" the Telmessee cdlectims thel-e is a fOl-iii almlldantlx" l-el)reselted lv well lweserxed specimels, of whicl after fl-equcnt -eviews [ have l»een unable t,, fix the svstematic positiol. It is a dicyclic cri,,id of Çalnel-ate aspect, with 5 1BII. stlggesti tbe 1-)imel-occinidae" l»ut it bas the RR in comact all around, with no anal in the CUl, wbich excludes tbat falnilv as well as the Rh,d,crilfidae. The dicvclic base excludes the 3Ielocrilidae, and «,tbec Çam- elate familles tlmt might be suggested. Excelt fol- this, there would be a some-  -. large RI¢, with one or two what near approach t,) tbe llatvc-inidae. T1 e e a-e . 1B-. filling ,mly part of the distal face, leaving well defined shculdel-S support- ing large iIr chiefly al)ove the line cf f¢R {pel-hals more popelly tegminal iAlb.), of wbich the poslerior ole seelns to le l-ather the lal-gest. Basals are lalge. CUlVilg into a shall,w c«mcax'itv, in whicb the fi ]I}[} f,-m a bl-oad. inverted coe. .rlnS are st,rot, lisel-ial. 2 ,,r 4 to the l-aV with occasionallv al,thel- l»iful-caticn. The lU,st remal-kalle charactel- is a long, spinose anal tube, x-lich projects bev,»nd the limits of lhe amns. Except for the well defined interbrachial plates resting o the radials, this form nfight fall under some of the dicyclic I.adunata" but with out present knowledge it mav as well be left in an imermediate lositio. In addition to the rive specimens figured in which more or less of the arms and anal tube are shown, and the two giving perfect internal and external views of the base. there are hall a dozen calices in which the saine type of dicvclic base clearly appearsso that the definition of characters here given mav be regarded as beyond question. It is a sigular fact that all the specù0ens in which the tube is shown differ from all çthers of the formatiçn, even those in the saine marix, in being very dark in colorwhich suggests the generic naine. leech River formation, Brownsport group, Niagaran" Decatur Çounty. Tennessee. PLATYCRI NIDAE 55 Section 2. Sulfamilv .IlAI¢SI]'CCR]NINAIï Bather Rays with olllv Olle primil)rach. Thc next subdivision, with ravs limited to a single primibrach, is abun- dantlv represented bv its earliest genus, remarkalle for the manner in which its lrachials to the axillarv secundibrach are buried in the cup. s as to produce a thoroughly Camerate structure, and for the constancv with which its charac- ters are maintained throughatt ntmerous species, now to le described. MARSIPOCRINUS Bather Platcs r3-rO .l[«rsupiocrinites Phillips (hOt de Blainville, 83o, in Murchison's Sil. Syst., 1839, p. 67z.--Austin, Ann. Mag. Nat. Hist., m, I84-', p. IO9. 3Iarsul, iocri, us McCoy, British Pal. Rocks and Foss, 1854, p. 54.--Wachsmuth end Springer, Rev. Pal., _% 88I, pp. 63, -3o; N. A. Crin. Cam., I897. p. 73o.--Weller, Bull. Chicago, Acad. Sel., 4, pt. 1, 19oo, p. I37. Marsipocrinus Bather, Quart. Jour. Geol. Soc. London, 45, I88O, p. 73; Treatise on Zool., 3, 19oo, p. 156, fig. 7o.--Bassler, Bibliogr. Index, Ara. Ord. Sil. Foss., IOIS, p. 786. Cupcllaecrinites Troost, Ara. Jour. Sel., I849, p. 49; Proc. Ara. Assn. Adv. Soi., I85O, p. 6 (not defined.-- Cpellaccrims Meek and Vorthen (not Steininger), Proc. Acad. Nat. Soi. Phil., I865, p. I6; Geol. Surv. Illinois, _*, i866, p. 7;.--Shumard, Trans. Acad. Soi. St. Louis, _, I866, p. 36 ; p. 387, footnote.-- Meek, Ara. Jour. Soi., I866, p. I8. Platvcrinidae with «me ] I_,r, small, axillarv, and I1P,r cm either side of it resting m RR and whollv incorporated in d-rsal cup. fcllc, wed by another axil- larv in case of further divisim" ,ne large iP, r supported bv shc, ulders of RR. flanked bv smaller crues at Upler c,rners  hich mav le restricted to the terrien : arms stout, biserial, two or four to the ray. with large pimmles: tegmen com- posed of numerous oE1nl. and i_-\ml, plates: anu.q subcentral, directlv through the terrien, without a tube" orals small, unsvmmctric, pushed anteriç)rl_v, the posterior plate letween the other four; stem circular in section, lumen large, usually pentagonal or l)entapetal(us • small basal at 1. ant. side. Gcnotype. Marsttpiocrimts coclattts Phillips. Distribution. Silurian to I.ower Devonian" England, Sweden, America. The naine ll[arsupiocr[ntts, proposed bv l-'hillips for the English species, was l»reoccupied bv «le Blainville. Altbough Troost's ls. naine. Cup«llaccriuitcs, given for the form after- wards described bx r Roemer as Platvcrintts tctttcssct'nsts, wêts adopted and pul»lished by 3[eek and \Vorthen and bv Shumard, it is held invalid bv most authors for conflict with Cypcllac- crintts of Steininger. Bather's modification of Pbillips's naine, proposed to relnedy the exist- ing confusion, has been generally accepted. \Vhile the European Silurian bas furnMaed some excellent examples for illustrating the structure of the genus, especially those fiured bv Anelin from I;otland. the little that has been published in regard to it in America has been far /rom commensurate with its impor- tance as now known. This has been due to the extreme raritv o¢ specimens hereto¢ore avail- able. \Vachsmutla and Springer for the Çamerata monograph had verv lneagre lnaterial, either of our own or in other collections. \Ve had onlv two specimens with the tegmen preserved. 56 S,XIITIISONIAN INSTITUTION which were considered quite wonderful, and the Troost collection which has since become accessible was hOt much better supplied. The few calices that had been picked up on the glades consisted mostly of the dorsal CUl), or of the basal plates only, with the surface more or less smoothed by. erosion, and such as wel-e fotlud were usually assumed to belong to Roemer's species, M. tcmwssee,lsis. The publication later of Troost's lnonograph (P, ull. 64, U. S. Nat. Mus., I9o9) indicated the existence of a wider range of forms than had been previously known, and brought out a number of new specific names, but the preservation of the specimens was for the most part poor, and not much aid was given toward fixing tlae diagnostic characters of the species. The elaborate original descriptions were of specimens rather than of species. The collection now assembled furnishes for the first time adequate material for the study of the American forlns of the genus, which seems to have flourished profusely in the Ten- nessee area. Most of it was derived fronl the shales of the Eucalyptocrimts zone of the Beech River formation. These vielded numerous specimens from the sort matrix, in exquisite preser- ration, admitting the most delicate preparation, by which the surface ornament, details of tegmen, and in many cases the arlns and pinnules, were brought to light with a perfection never before seen in this country. The study of this collection bas resulted in the recogni- tion of ten species belonging to this field alone, of which three are new, while rive of those proposed by Troost are confirmed by ample evidence among the new material. Thus we are able to place the leading species upon a firm footing, and to bring out in detail the great diversity by which the gentls is characterized upon a well defined structural plan. In other areas a species has been described by \Veller from the Racine dolomite at Chicago, and one bv Hall from the Ohio Silurian, as well as from the IIelderbergian of New York, by which the range of the genus is extended into the Devonian. Of tb_e Europeau Silurian there is a fine species from England, and four from Gotland described by Angelin, some of which may be synonyms. These fonns for the most part differ consistently from the American species. A notable fact is the extreme rarity o.f this genus in the Laurel formation of St. Paul, where its presence is barely indicated by a few fragments. No genus of fossil crinoids is more clearly defined than Marsipocrin,«s. The general form, with broadly arched tegmen, and the peculiarity bv which the secundibrachs rest directly upon the radials and are thus, as well as by contact with the large interbrachials, incorporated it the cup, impart a certain physiognomy by which it is readilv rec%onized. Typicallv the calyx is low and broad in the proportion of I to 3, or I to 2, with somewhat less differece in the English species. From others of the falnily it is also decisivelv set off by its many-plated tegmen and large stem-hlmen. Within the genus there are several prominent specific characters by which the limits of the species are fairly well defined: I. Form of calyx, which may be either--a, concavo-convex or hemispheric, with radial facets directed below the horizontal, and tegmen exceeding dorsal cup in size" or b, bi-convex, with radial facets intermediate and tegmen about equaling dorsal cup; or c, convex conical; dorsal cup deep convex, tegmen low conical, constricted, narrower than cup. 2. Basal penta..on fiat or convex with raised margil, to concave with basals at bottom of cavity. 3. Interbrachial plate pro.iecting witb corrugated arch, or smooth without pro.iection. 4- Tegmen either--a, sharply tubercular, or with raised', an.,.mllar, diamond-shaped plates, and ambulacra not conspicuous; or, b, smooth, or with rounded plates, and ambnlacra well defined. 5- Surface markings either--c, coarse granular; b, corrugated, with coarse wrinkles or tuberdes; c, tubercles confluent forming more or less interrupted lines or coarse striae part way on plates; d, fine striae traversing the plates; e, entirelv smooth. 6. Number of arms, 2 to the ray as in most American species, or 4 to the rav as usual in the European species. PLATYCRINIDAE 57 Marsipocrinus rosaeformis (Troost) Platc _r 3, fic.qs. I78; I5, ficds. O, ça Cupellaecrinites rosaeformi.¢ Troost, Ara.. Jour. Sci., I849, p. 419; Proc. Ara. Assn. Adv. Sci., 85o, p. 6I (nom. nud.).--Cupcllaecrinus rosaeformis Shumard, Trans. Acad. Sci. St. Louis, 2, 1866, p. 36L Marsipocrinus rosa.eformis (Troost) \Vood, tlull. 64, U. S. Nat. Mus., 9o9, p. 37, pl. 3, figs. 5, 6. A large species, typical specimens I2 nm. height of calvx by 3 ° 111111. xvidtb, to a maxinmm of 5 by 40 mm. Calyx concavo-convex or lemispheric; if rest- ing on a plane surface will touch bv radials or afin-bases. Basal pentagon fiat, relatively small, about one third the total diameter, usually with a small rira around the column-facet. RR horizontal, with facets directed out or down- ward; axillarv IBr ,,'er 3- small, triangulal", uot over one tbird the width of the radial, flanked bv large transverselv elongate IIBr which rest upon the radial and meet by their short inner faces above the axillary; they curve around on the outer side, abutting upon the large iBr and the smaller ones above, and are followed by higher brachials leading to the biserial arms. iBr large, arched, projecting in a curved lip outward and upward, often strougly corrugated or wrinkled, giving to lhe calvx a decagonal outline as seen from above; a much smaller plate abreast of the iBr at either side rests upou the IIBr, sometimes limited to the tegmen. Arms stout, biserial, two to the rav. T%o-men broadly arched, larger than dorsal cup; plfites strongly uodose, shading to angular in some specimens, somewhat obscuring the ambulacra, which are not conspicuous. Surface ornament of cup verv strong, either lu form of a simple corrugation with wrinkles or tubercles hot forming lines, or more or less confluent in radiat- ing lines forming triangles, or parallel striae. l'l-ris is the most prominent species in the Tennessee collections, represented by many fine specimens mostly obtained from the excavations. Comparison of Troost's type specimen in the National Museum, as figured in 9o9, although in poor condition, established that the henispheric calyx is the typical form, and enables us to assign to the species the other char- acters so fully illustrated bv the new material. The specimen figured herein, pl. 5, figs. 9. 9a. reproduced from mv work on çcyphocrim«s, 97, pl. 9, figs. 5, 5a, as M. tcwssecnsis, is probably referable to this species. Horizon atd locality. Chiefly Eucalyptocrim«s zone of the Beech River formation, Brownsport group, Niagaran; Tuck's Mill, near Decaturville, Decatur County, Tennessee. Marsipocrinus tennesseensis (Roemer) Plate -I, figs. -6 Platycim«s temtessee»zsls Roemer, Sil. Fauna \Vestl. Tennessee, I86o. p. 35, pl. 3, figs. 4a-f.oElatycrim«s (Cupellaecrinus) tennesseensis Shumard, Trans. Acad. Sci. St. Louis, 866, p. 362. .l[arsupocri»zus tennesseensis, \Vachsmuth and Springer, Rev. Pal., 2, 88L p. 65: Proc. Acad. Nat. Sci. Phil., 888, p- 373, pl. 2o,. fig. 7; N. A. Crin. Cam.. 897. p. 7., pl. 75, figs. 6a, b.--\Vood, ]3ull. 64, U. S. Nat. Mus., 9o9, p. 3, pl. 9, figs. 5, 6.--]3assler, Bibliogr. Index, 915, P- 788. Similar to M. rosaeformis in size. geueral proportions and form of iBr plate, but witb calyx bi-convex, and dorsal cup and arched tcgmen about equal. . SMITIISONIAN INSTITUTION l;asal pentag,n l»l-q),l-ti,,lmlly lal-.-er ; surface ornalnel]t similar but usually less lronCmnced. Radial facets directcd al»ove the horizontal. TeRmen plates raised, s»mewhat n,-,dose, angular, or Slooth ; amlndacra fairlv dcfined. Roemer's P. tcnnesscensis as described by him contains two species, of which his figures 4a, b, c, must he taken for the type. His specimen was weathered, and surface of both cup and tegmen probably eroded, llut the characters above specified are sufficient to identify the species, of which XVachsmuth and Springer figured a well preserved example (N. A. Crin. Cna., pl. 75, fig- 6, but hot fig. 7)- Horizon and localitv. Beech River formation, Iirownsport group, Niagaran ; Eucalypto- crinus zone and glades, Decatur County, Tennessee. Marsipocrinus striatus (\Vachslnuth and Springer) l'latc z1, figs. ï-z  Marsuplocri»us striatus Vachsmuth and Springer, N. A. Crin. Cam., 7, p- 73z, pl. 75, fig- 8 only. Not Cupellaccrinus striatus Troost, nor Marsipocrinus striatus, Wood, Bull. 64, U. S. Nat. Mus., , P- 33, pl. 9, figs. 3, 14M. infatué. A S«,lnewhat smaller species than the precedinx, varying fl-om r2 to 14 ri]iii. hei-ht of calyx to 5 t« 26 mm. diameter. Calvx lfi-convex, dorsal cup usually higber than tegmen. Basal pemaon shallowlv depressed, al»out one hall the total width. Radial facets directed upwards, iBr usuallv nt projectinç, smooth, curvin over ede «,f tegmen. Tegqnen low, l»lates rounded, smooth and but Iittle raised, leavin ambulacra well defined. Surface of cup usuallv striate, continuous from plate to plate, sometilnes rather owrugate with striae more obscuremuch dependent upon preservation. A considerable number of specimens answer to this description, and agree fairlv well with the type of Wachsmutla and Springer, pl. 75, fig- 8. It is a variable form, tending to shade into other species, but the strong striate ornament and prominent exposure of ambu- lacra are the features chiefly relied on. In specimens from the glades the striae are usually much obscured by weathering, for which allowance must be ruade. Horizon a,d localitv. Beech River formation, Brownsport group, Niagaran; Tuck's Mill and on glades, Decatur County, Tennessee. Marsipocrinus inflatus (Troost) llatc z 5. ficd s. _r-8 Cupcllaecrinites i,aatus Troost, Proc. Ara. Assn. Adv. Sci., 185o, p. 6I.Marsupiocrinus Wachsmuth and Springer, iN. A. Crin. Cam., I897, pl. 75, fig. 17.--Wood, 13ull. 64, U. S. Nat. Mus., 9o9, p. 34. A fairlv lar,e species, with calvx relativclv hip,h, the averae hein al)out 20 mm., by 3 ° mm. wide. Dorsal cu l) o,nvex and rather deep; basal pentagon large, about three fifths the total diameter, margins usuallv notchëd at the inter- basal sutures, and s,,metimes xx'ill slight pr,trusions at the middle of the sides. iP, r hOt projecting, but flush with calvx wall and curvinR over into the teglnen. PLATYCR[NIDAE 9 Arms stout, two to the rav. with pinnule l)el]in.gs 1,etween their bases rimes seen. Te..o.men Ioxv cc, nical, al)rul,tly constricted al»ove the avm-bases, and distinctlv narvower thal the cup; plates ttat or low c¢,lavex, smooth or studded with small tulercles : amlulacra n,,t con.picu,-,us. Surface of CUl) ,,rnate. usuallv corrugate, sometimes xvith rid-es f,»vming stviae, ol- lines parallel to mal-gia of plates: sutures often sharply 1)eveled. A xvell marked species, usuall.s readily recognized bv the high calyx, large basal pen- tag.o, and a certain massiveness hOt al»parent in most other species. The constricted tegmen is very decisive, lut this is seld«m preserved, and with onlv the dorsal cup the large pentagon and vertical sides are usuallv sttfficient. In well preserved specimens the sculpturing i higlaly ornate. This is clearly the form described lv Troost under the names C. striatus and C. in- flatus, as shown bv lais type of the latter, and the figures of the former in the monograph of ]0OE), pl. 9, figs. 13, 4- The first naine being preoccupied by \Vachsnmtla and Springer, the last shofld stand for the species..\ specimen of it xvas figured l»y us as M. temcsseensis (N. A. Crin. Cana., I897, pl. î5, fig. I7 only). The enlarged details of a specimen of this species shown bv figure 8 of plate ]5, alog with ancther which mav be of M. rosacfornis, are reproduced from nav works on .çcypho- c'inus, ]0I 7. pp. 33-38, pl. 9, figs. 5a-c. and Dolarocrinus, Bull. ]]5, U. -q. Nat. Mus., ]92I, p. 24, pl. 2, figs. 3, 4- They were -iven for demostrating the true nature and function of the interbrachial apertures observed in various genera of the Camerata. and frequently desig- nated as " respiratory pores," which are now seen to be the openings for pinnules, the ambu- lacra leading to which are shown in some specimens of other species. For a full discussion of this subject, and the significance of these specimens, reference should ie had to those papers, at the pages indicated. HoHzo and localitv, l leech River formation, chiefly Eucalyptocrinus zone, P, rownsport group, Niagaran ; Tuck's Mill aad glades. Decatur Cotmty, Tennessee. Marsipocrinus verneuili (Trc«st) Plate _r 6. figs. _r-6 Ct«pcllaccrinitcs z,crneuili Troost, Proc. Ara. Assn. Adv. Sci., xSSo, p. 6t (nom. mtd. J.--.Uacsipocriutts ;'erteuili (Troost), \Vood. Bull. 64, U. S. Nat. Mus., 9o9, p- 32, pl. 9, figs. o, II, I2. A small species, average diameter of calvx al)out 5 mm. Calvx 1)i-cc, nvex. with shalh-,w colacave base. heig-ht t, width al,,ut as l to 2. P, asal pentagcn aboutit ball the tc, tal diameter, br,adlv e×cavate. 1),tmded by a conspicu«»us, c,btuselv trial.gular rira. much larger thala tbe c,,lumn-facet, flaring cutxvavd tc a sharp edge. iP, r nct lr¢,jecting, bent over int,-, the te3nen. Arms taperil, two tc the rav. Tegmen lower ttaal cup, xvith h,w. SlnC«thlv rounded plates" ambulacra narrow, uell defilaed, with some outer divisiola« 1-unniag to pimaule ,)pelings. Surface of cup coarse striato-o,rruvate ,,r ru.ose. This species as represented bv Troost's type is well defined, and is confirmed bv seven specimens in the present collection. The flaring rira around the column is a striking character, seen to some extent in other species, but in none so conspicuous as this. Horizon. and local#v. P, eech River ormation of P, rownspsrt group. Eucalyptocrhnts zone, Xiagaran" Tuck's 5IiI1, Decatur Çounty, Tennessee. 60 SMITIISONIAN INSTITUTION Marsipocrinus excavatus lleW species Plate _r6, fiçs. 7-7 b Calyx plano-convex, with basal pentagon abruptly sunken around a small, round column-facet, iBr projecting in small points. Tegmen conical, higher than cup; plates low, covered with small tubercles. Surface markings on cup coarse, with irregular strong wrinkles and obscure striae. Founded upon a single specimen 3 mm. high by _'28 lnm. wide, with basal pentagon about one third the total diameter. Horizon and locaHty. Eucalyptocrinus zone of Beech River formation, Brownsport group, Niagaran ; Tuck's Mill, Decatur County, Tennessee. Marsipocrinus concavus new species Plate _r6, fig. 8 Calyx with deep funnel-shaped basal cavity, involving part of the radials. P, asal pentagon very small, ahnost covered by column at bottom of cavity, bor- dered by a rhin rira. Radials long, extending far dovn into the basal cavity. Surface ornament strong, composed of some irregular striae, and concentric ridges roughly parallel to margins of pentagon. Tegmen and other parts unknown. A thoroughly distinct species, differing from all others as Pisocrinus quinquelobus differs from species with large basals. Unfortunately represented by only a single imperfect speci- men consisting of basals and radials. Horizon and locality. Eucalyptocrimts zone of Beech River formation, Brownsport group, Niagaran ; Tuck's Mill, Decatur County, Tennessee. Marsipocrinus stellatus (Troost) . Plate _r 7, fic.qs. _r-_r o Cupellaecrlnites stellatus Troost, Ara. Jour. Sci., x849» p. 49 ; Proc. Ara. Assn. Adv. Sci., x85o, p. 6 (nom. nud.).--Cupcllaccrim«s stcllatus Shurnard, Trans. Acad. Sci. St. Louis, 866, p. 36.larsipocrinus stcllatus (Troost) Wood, ]3ull. 64, U. S. Nat. Mus., 9o9, p. 36, pl. IO, figs. x, . A rather small species, w':th dorsal cup perfectly smooth, ranging froln 8 and o lnm. height of calyx to 6 and 24 lnln. width. Calvx bi-coin'ex, broadly spreading, with base fiat or sligbtly convex, t3asal pentagon about two fifths the total diameter; interbasal sutures often obscure, i]3r with rather sharp pro- jecting lip. Arlns directed horizontal, long and slender toward the extremities, two to the rav. Tegmen broadlv rounded, smooth in interalnbulacral regions, or with scattering sbarp nodes; ambulacra conspicuous from middle to afin- bases, with some outer branches leading to pinnule openings. Surface of cup entirely devoid of ornalnent. Stem stout, tapering distallv dividing into terminal branches for attachment. The smooth surface in this species is hot a matter of erosion, but is a thoroughly definite character, as is shown by at Ieast a dozen specimens in the collection, mostly well preserved I'LATYCR I X I DAE 6I in the matrix and several with arms and stem attached, in none of which is there any trace of surface markings. The tendencv is toward anchylosis of the basals. Along with these characters the low and broadlv spreading calyx makes the species readily recognized. Horizon and localita,. Eucalyptocrinus zone of Eeech River formation, Erownsport group, Tuck's lIill, Decatur County, Tennessee. Marsipocrinus striatissimus new species Plate ±8, figs. ±-7 A Yerv lare species, attaining a diameter of .5o or 6o mm., with ext-emely rhin plates, sa that specimens are rarelv round undistovted, or with anything lut the basal pentaR-on preserved. Çalvx low and broadlx- speadin, xvith arm facets directed about horizontal. Base convex, xvith narrow romaded rira about column lacet, iBr projectin.e, but little, mostlc smooth. Terrien low. usuallv cvushed, xvitla plates level, smo,th, or covered xvith small lodes or tubercles; ambulacra hot conspicuous. Sm-face of cup marked lx- an exceedingly fine striatio, xvith straight lines ccossin the sutures from plate to plate. Roemer's figure 4d naav be of lhis species, and it was also this which \Vachsnmth and Springer had in mind when in describing their much smaller and more robust M. str[alus they stated that it sometimes reached 6 cm. in width. It is nct uncommon on the glades as fragments only. characterized by large size and the extreme thinness of the plates. The crushed specimen figured on plate 8. figures , a, is the nearest to a complete calvx that is known. Two fairlv robust dorsal cups have the characteristic delicate striation, while in the specimen with arms it is almost obliterated by pressure. Hori=o. ad localiy. Etcal3'Pocrinus zone o Eeech River formation, Brownsport group, Niagaran : Tuck's Mill and glades, Decatur County, Tennessee. Marsipocrinus magnificus (Troost) Plate zo., .figs. z-b C«pellaecri»Htes ntagnitcus Troost, Proc. Ara. Assn. Adv. Sci., I85O, p. 6 (nom. uud.).--Cupellaecrinus ma9nitc«s Shumard, Trans. Acad. Sci. St. Louis, 2, 866, p. 36L Marsipocrinus mag»,ic,«s (Troost) \Vood, Bull. 64, U. S. Bat. Mus., I9O9, p. 34, pl. o, figs. 5-7- A verv larg-e and robust species, with four arms to the rav. Clvx bi- covex : hei-ht _2 7 mm. xvidth 4o mm. Base about fiat. with a thickeled romaded rira surroundin.o.e, tlle colunm-facet : basal pentago about three fifths tlae diame- ter of calvx. Two secundibrachs in succession meet al)ove the tviangulav p-imi- brach, the second one axillacx', folloxved bv a second divisio of the rav. giving fouc arm openi,o.e,-s instead of two as in all the preceding species, iBr verx- large, b-oadlv shield-shape, tcuncate above, and but little projecting. Tegmen com- posed of stro.,o conx'ex or nodose plates, uith ambulacra hOt conspicuous. Sm-face of cup deeply sculptm-ed, with beveled sutures, ap._d coarse tubercles coalescin into pominent ridges to the corners of the basal pentagon, and from there across the radials, forming conspicuous triangles uith apex at the ptimibrach. 5 62 SMITHSONIAN INSTITUTION Known only from the fine and perfect calyx of the type specimen in the Troost collec- tion. and distinguished from all other known American Silurian species by having four arms to the ray, as in the Englisb and Swedish species. But it is remarkable that whereas in the latter the interbrachial plate is compressed by the increased number of arms sa that it is elon- gate and pointed above, in the present species it is wide and broadly truncate al»ove as in the 2-armed forms, the expansion at the arm bases being accommodated by the great convexity of the tegmen. In fact, aside from tbe number of arms this species bears hot the slightest resemblance to the European forms. That other species with 4 arms existed in the Tennessee area is indicated by two fragments from Wavne County, insufficient for description. 14orizo-** ad locality. P, rownsport group, Niagaran; Decatur County, Tennessee. Marsipocrinus turbinatus new species Plate 7, figs. -3 Among all the collections from the Laurel forlnation at St. Paul the four franentary bases here figured are fle only specilnens round belonging to tbis gelms. They are of a wholly different type froln all the other known species, with their turbinate base indicating a more or ]ess elongate calyx; but the pen- tagonal form, with the riln surrounding the cabrera-lacet, and the large lumen. would seeln to settle lhe generic affinities of the species. Horizn and Iocalitç. Laurel formation, Niagaran; St. Panl, Indiana. Marslpocrinus coelatus Phillips Plate _r9, figs. -7 Marsuplocriites coclat«s Phillips, Murchison's Sil. Syst., I839, p. 672, pl. 8, fig. L--Austin, Ann. Mag. Nat. ttist., 84 -, p. o9.Bather, Lankester Zool., pt. 3, P. I57, fig. 70. A mediuln sized species. Calvx convex-conical, ranging from 7 to  5 mln. height to 2 to 3 ° mm. width. Dorsal cup rather deep, broadly rounded below; basal pentagon nearlv fl.at, sometimes excavate, about one third the total width. RR mostly horizontal in mature specilnens- IBr rather large, triangular ; IIBr 2 in series, the second one axillary for a secon,.l division, followed bv 2 or 3 bra- chiais passing into the bi.erial arlns. Arlns 4 to the ray, directed vertically, fairly stout, iBr e]ongate, narrowing to an apex between the rays, almost com- pletely enveloped by the lower ]rachials and incorporated in the dorsal cup. Tegmen low conical or rounded, composed of numerous slna]l plates, often covered by a gastropod COlnmensallv attacbed over the anus: alnbulacra hot prominent, but distinctly marked bv small covering plates, with outer branches running to ilterbrachial pinlmle openings. Surface of cup striato-corrugate, marked in xvell preserved specimens bv strong ridges crossing the sutures, but more often obsolete. Stem stout and appareltly fixed. An abundant and well known species of the lZnglish Si]urian, here figured for com- parison: it has been best illustrated heretofore by Bather in the Lankester Zoology, part 3, page 57, figure 7 o. Specifically it bears little resemMance to anv. American form, while it is a fine representative of the 2o-armed type which seems to have predolninated in tbe European PLATYCRI NIDAE 6 3 area, in contrast to that of IO arms chiefly characteristic of the American ocks, from which itis also sharply distinguished by its elongate, pointed interbracbial plate. A feature of this species hot heretofore mentioned to my knowledge is the tendency to grov in clusters, several individuals in a group being attached by their stout stems to corals or other fixed objects. I ana illustrating this by a slab from Dudley, shown bv a reduced photograph on plate 19, vith nine stems springing from a common base, four of them with the crowns attached and visible, and the others with the crowns imbedded in the matrix. Such a multiple fixation is unusual among crinoids, but here it seems to be a character more than merely incidental, as other specimens are kuown, one very fine one, for example, in the Dudley Musemn, and another in the collection of the late Mr. Charles Holcroft, now in the IIuseum of 13irmingham. Horizon and locality. Wenlockian group, Silurian; Dudley, England. Of other described species there are one bv \Veller from the Racine dolomite, one bv Hall from the dolomite at Cedarville, Ohio, one by Hall from the Helderbergian of New York; and four by Angelin from Gotland. 64 SMITIISONIAN INSTITUTION Order FLEXIBILIA Zittel CRINOIDS WITH A FLEKIBLE CALYX IN WIIICII TIIE LOWER lqRACIIIAI-S ARE LOOSELY  INCOR- PORATED INTO THE DORSAL CUP EITIIER II,'V LATERIAL UNION WITtI EACFI OTHER, BY MEANS OF INTERBRACHIALS, OR OF A LOOSE SI:IN STUDDED WITH CALCAREOUS PARTICLES..ALL PLATES BEYOND TIIE RADIALS UNITED B LOOSE SUTURE, AND MORE OR LFSS MOVABLE. MOUTH AND TEGMINAL FOOD GROOVES EXPOSED. PASE DICYCLIC, WITI{ "r'I{REE I'NFRA- BASALS, UNEQUAL. ARlXtS NON-PINNULATE. STElXI ROUND. In view of the fact that this order of the Crinoidea bas recently been treated mono- graphicaIIy in mv work on the Crinoidea Vlexibilia, 2 volumes 41o, Smithsonian Publication 25Ol, 192o, in which nearly all the species occurrin K in the areas here under consideration have been fullv described and their generic relations discussed, it is hOt deemed necessary to repeat the descriptions, or to do more than give a list of the Kenera and species with references to that work where the complete bibliography will be round, togelher with a selection of the principal figures--for the greater convenience of students of the Si!urian faunas. Of the Flexibilia group there have been recognized from this area IO genera and 18 species, all bttt two of the genera from Tetmessee. Three of the species are new :   are from Tennessee, 6 from ldiana, and one from Obio. They are distrilmted amonK the four fami- lies of the order as follows : Lecanocrinidae 12, Sagenocrinidae 2, lchthyocrinidae 2, Taxo- crinidae ". Thus the great preponderance of this type as round in the present collections be- longs to the small, robust and better preserved Lecanocrinidae. Of the ten genera, nine are common to both Europe and America. Of these, six were formerly considered to be exclusivelv Swedish and English. One newly described genus is represented bv species from both continents. One highly typical Gotlandian and English genus, Pycnosaccus, hitherto barelv recognized in this country, appeared in the Beech River formation in considerable abundance, one species of which can scarcely be distinguished from its foreign prototype. Sagcnocrimts , another specialized form of the European Silurian, is represented here by a thoroughly typical species. And a third, Gtorimocrius, now appears for the first time in .\merica. Besides these important contrilmtions from the Tennessee Silurian there are two well defined new genera, Hormocrimts and Asaphocrinus, in the form of finelv preserved specimens, the first of which also occurs in Europe as new species. Thus the Flexibilia, usually the rarest of the crinoids, take their place among this fauna as one of its most important constituents. Suborder SAGENOCRINOIDEA Posterior interradius either hot differentiaed or containing anal plates, hot usually formed into a tube. the first of which is incorporated in the calvx bv sutural union with adjacent brachials for at least part of its height on hoth sides; posterior basal, if difl:erentiated, truncate or angular, and suturallv con- nected with succeeding anal plate. Family LECANOCRINIDAI?; Sprinaer lnfrabasals more or less erect, forming an essential part of the calvx wall" crown usuallv short, rotund. LECA XOCRI N 1 DAE 6 5 LECANOCRINUS Hall Plate 20 Lecanocrinus Hall, Pal. New York, 2, I852, p. I99.--Springer, Crinoidea Flexibilia, I92o , p. I25. Ravs in contact except at the anal side. Radianal rhombic, obliquelv to lower left of r. post. R. Anal .r alone. Arms dichotomous, interlocking. Genotype. Lecanocrim«s macropetalus Hall. Distribution. Silurian to Devonian" Gotland, England, America. Lecanocrinus pusillus Hall Plate 2o, fige. _r- 5 Lecanocrim«s pusillus Hall, Trans. Albany Inst., 4, I863, p. 2oo.--Springer, Crinoidea Flexibilia, 192o, P. I3L pl. , figs. -3. \Valdron shale; \Valdron, Indiana" Newsom, Tennessee. Lecanocrinus pisiformis (Roenaer) Plate 2o, figs. 6-2 Poteriocrinus pisiformis Roemer, Sil. Fauna \Vestl. Tennessee, 86o, p. 54, pl. 4, figs. 7a-d.--Lecanocrinus pisiform4s Springer, Crinoidea Flexibilia, I92O, p. I35, pl. , figs. 4-36. P, eech River formation; Decatur County, Tennessee. Lecanocrlnus elongatus new species Plate 2o, figs. 3, 4 Similar to L. pisiformis, but crown more elongate, and basals relativelv higher. Laurel limestone; St. laul, hadiana. Lecanocrinus meniscus Springer Plate 20, figs. r5-±sb Springer, Crinoidea Flexibilia, I92O, p. 14o, pl. , figs. 37a-c. ]3eech River formation; Decatur County, Tennessee. Three species have been described from the Rochester shale, one from the Racine, and one from the ainbridge of Missouri; and o species described as Lecauocriuus have been referred to other genera. See ]3assler's ]3ibliogr. Index, page 692. ANISOCRINUS Angelin Plate 20 tnisocrimts Angelin, Icon. Crin. Suecc., 878. p. 13.--Springer, Crinoidea Flexibilia, I9---'o, p. 6o. Rays above radials separated by solid plates arched over by brachials. RA irregularly under r. post. R, above line of ]3]3. Anal .r and one large iI3r alone or followed bv others. Arms dichotomous. Gcnotype. ,uisocrimts iuterradiatus Angelin. Distributiou. Gotland, Alnerica. 66 SMITHSONIAN INSTITUTION Anisocrinus greenei (Millet and Gurley) Plate 2o, figs. t6, 7 Lecanocrbzus 9rccnei Miller and Gurley, BuIi. 8, Illinois St. Mus., 1896, p. 52, pl. 3, fig- 28.--Anisocrinus 9reend, Springer, Crinoidea FIexibilia, I92O, P. 163, pl. IO, figs. 8, 9- Louisville iimestone; Jefferson County, Kentucky; Eeech River formation, Decatur County, Tennessee. There are also figured for comparison" Anisocrimts o,egoensis (Miller and Gurley), plate 20, figure 18, from Crinoidea Flexi- billa, plate IO, figures 7a-c. Oswego, Illinois. Anisocrimts angclini \Vachsmuth and Springer, plate 2o, figure 19, from Crinoidea Flexi- bilia, plate IO, figures 4a, b. Gotland, Sweden. HORMOCRINUS Springer Plate 22 Hormocrim«s Springer, Crinoidea FIexibilia, 19-'o, p. 16o. Ravs above radials separated by solid plates followed bv perisome. !N'o RA. Anal x and large iBr followed by otbers abreast and perisome, or directly by perisome. Arns dictaotomous. Gcnotypc. Centrocrim«s tcnnessecnsis \Vorthen. Distribution. Silurian" America, England, Gotland. Hormocrinus tennesseensis (\Vorthen) Plate 22, fiçls, t-3b Centrocrim«s tcmwssccnsis çVorthen, Geol. Surv. Illinois, 8 189o, p. 96, pl. 14, fig. I.--Hormocrinus ten- ncsseensis, Springer, Crinoidea Flexibilia, 192o, p. 167, pl. 14, figs. I-5. Beech River formation; Decatur County, Tennessee. ASAPHOCRINUS Springer Plate 20 • 4saphocrinus Springer, Crinoidea Flexibilia, 192o, p. 174. Rays above radials separated by perisome only. RA rhombic, obliquely to left of r. post. R. Anal x followed by others passing into a tube. No iEr, areas filled with perisome, SOlnetimes hot expose& Arlns dichotomous. Gcnotype. .4saphocrim«s b«sslcri Springer. Distributiou. Silurian; America. Asaphocrinus bassleri Springer Plate œeo. figs. 20, 2r Springer, Crinoidea Flexibilia, gzç, p. x78, pl. lO, figs. lO-I4. Beech River formation; Decatur County, Tennessee. LECANOCRINIDAE 67 Asaphocrinus minor new species Plate 20, fig. 22 An imperfect specimen lackiug the basal parts, referred with doubt to this genus. The general proportions, distribution of arms, and extent of anal struc- tures, are in fayot of it. Laurel limestone; St. Paul, Indiana. PYCNOSACCUS Angelin Plate 21 Pycnosaccus Angelin, Icon. Crin. Suecc., 1878, p. I3.--Springer. Crinoidea Flexibilia, I92O, p. 18o. Ravs al»ove radials separated bv perisolne onlv. RA rholnbic, obliquely to left of r. post. R. Anal .r alone, followed by perisome. IBr I to 4. Arms dichotomous.- Genotype. Cyathocrinitcs scrobiculatus Hisinger. Distribution. Silurian to Devonian; Gotland, England, America. The first indication of the presence of this genus in America was given by the imperfect specimen described by \Veller in 19oo as P. americamts from the Racine dolomite. It has since appeared probable that the species described bv Hall as Lecanocrimts caliculus from the Clinton of New York belongs here. Recent discoveries have extended the range of the genus into the Lmver Devonian, and perhaps into the middle Devonian of Canada. The material from the Beech River formation of Tennessee not onlv furnished fine specimens for illus- tratilg the general habitus of the genus, but has tbrown a flood of light upon its detailed structure, by means of which its actual characters became for the first rime understood. Pycnosaccus patei Springer Plate 2, figs. >4 Springer, Crinoidea Flexibilia, I92O, p. 186, pl. 12, figs. 1-9. Beech River formation; Decatur County, Tennessee. Pycnosaccus welleri Springer Plate 2, fis. 5-7 Springer, Crinoidea Flexibilia, I92O, p. 186, pl. 13, figs. 3-5. Beech River formation; Decatur Cov.nty, Tennessee. Pycnosaccus laurelianus new species Plate 2, fi9s. 8, Sa A small species (the figures are double size), with more robust arms and smaller radianal than the Tennessee forms, and a peculiar upward videning of the anal plate hot observed in others. Laurel limestone; St. Paul, Indiana. 68 SMITHSONIAN INSTITUTION Pycnosaccus dubius Springer Plate 2 r. figs. o. 9a Springer, Crinoidea Flexibilia, 192o , p. 189, pl. 13, figs.  a, b. eech River formation; Decatur County, Tennessee. Family SAGENOCRINIDAE Roemer emend. Springer Infrabasals more or less recumbent, taking little part in calyx xvall. Crown usually elongate. Rays above radials partly or wholly separated. SAGENOCRINUS Austin Plate 22 SageuocriMtes Austin, Ann. Mag. Nat. Hist., 842, p. o.çagnocrinus Springer, Crinoidea Flexibilia, I920, p. 215. RA obliquely under r. post. ray, more or less between BB. Post. P, truncate. Anals and iBr numerous. Arms dichotomous, hot abutting. Gcnotype. Actinocrinites? c.rpansus Phillips. Distribution. Silurian; England, Gotland, America. Sagenocrinus clarki Springer Plate 2_,, figs. 4, 4a Springer, Crinoidea F]exibilia, 92o, p. 2eo, pl. 9, figs. 4a-d. Beech River formation: Decatur County, Tennessee. Sagenocrinus americanus Springer Plate 22, fig. 5 Springer, Ana. Geol., 30, I9o2, p. 86; Crinoidea Flexibilia, i92o, p. 22L pl. 9, fig. 5. \Valdron shale; Valdron, Indiana. Familv ICHTHYOCRIN1DAE Angelinemend. \Vachsmuth and Springer 1-nfrabasals horizontal, hot appearing externallv and taking no part in the calvx wall. Crown elongate or rotund. Rays widening upward to accommo- date expansion of calyx, lmt in close contact, usuallv interlocking or abutting above interbrachials. ICHTHYOCRINUS Con,ad Plate 22 Ichthyocrims Conrad, Jour. Acad. Nat. Sci. Phil., 8, I842 , p. 279.Springer, Crinoidea Flexibilia, 02o, p. 264. - Rays in contact all around. RA in form of R under r. post. R. No anal or iBr. Post. B hot differentiated. Arms dichotomous, interlocking. Genotype. Ichthyocriuus laevis Conrad. Distribution. Silurian to Devonian" .\merica, England, Gotland, Bohemia. TAXOCRI NIDAE 69 Ichthyocrinus subangularis Hall Plate 22, fiqs. 2, 3 lchthyocrhn«s subangularls Hall, Trans. AIbany Inst., 4, I86O, p. 2oI.--Springer, Crinoidea Flexibilia, 192o, p. 281, pl. 34, figs. I-Io. \Valdron shale; \Valdron, Indiana. CLIDOCHIRUS Anffelin Plate Clidochirus Angelin, Icon. Crin. Suecc., 1878, p. I2.--Sprlnger, Crinoidea FIexibilla, 192o, p. 294. Ravs in contact except at anal side. RA iii fOl'lll Of R under r. post. R. Anal x alone or followed bv others. Post ]3 truncate. Al-ms dichotomous, interlocking. Gcnotype. Clidocl, irus t, yrum Angelin. Distribution. Silurian to Devonian: Gotland, America. Clidochirus americanus Spl-ingel- Pla te 2 z, fi9s. zo, z r Springer, Crinoidea FIexibilia, I92O, p. -'298, pl. 37, figs. 7, 8. Clinton" Dayton, Ohio. Suborder TAXOCRINOIDEA Family TAXOCR]NIDAE \Vachsmuth emend. Springer Posterior interradius always differentiated and occupied bv anal plates in a tube-like series, none of which are hlcorporated in the calyx. All anal plates ffoin post. ]3 up separated bv perisolne from adjacent brachials at one or both sides. Distal face of post. B not suturallv connected with anal plate. Rays above radials partly or whollv separated all around. Cl-ovn usuallv elongate. PROTAXOCRINUS Springer Plate 2_) Prota.rocrim«s Springer, Crinoidea Flexibilia, 192o, p. 345. RA in form of P,. under r. post. P,.. i]3r few. or perisome. Arms dichotolnous. Genotype. Taxocrinus ovalis Angelin. Distribution. Rays wholly separated by iBr Ordovician, Silurian, Devonian; Gotland. America. 70 SMITHSONIAN INSTITUTION Protaxocrinus robustus Springer Plate ce, figs. 6, î Springer, Crinoidea l:lexibilia, I92o, p. 349, pl. 45, figs. 9-I. Beech River formation; Decatur County, Tennessee. GNORIMOCRINUS \Vachslnuth and Springer Plate 22 Gnorimocrinus SVachsmuth and Springer, Rev. Pal., I, :t879, p. 5o.--Springer, Crinoidea Flexibilia, 92o, P. 353. RA rhombic, obliquely to left of r. post. R. iBr few, rays wholly separated by iBr or perisome. Arms dichotomous. Genotypc. Tarocrimts e.rpansus Angelin. Distribution. Silurian; Gotland, America. Gnorimocrinus cirrifer Springer Plate 22, figs. 8-o Springer, Crinoidea :Flexibilia, 92o, p. 355, pl. 47, figs. 7-I. ]eech River formation; Decatur County, Termessee. Gnorimocrinus varians Springer Plate 2, figs. H, Ha Springer, Crinoidea l:lexibilia, 9o, p. 356, pl. 47, figs. 3-7. ]eech River formation; Decatur County, Tennessee. PISOCRI N I DAE 71 Order INADUNATA Wachsmuth and Springer CRINOIDEA WITH A RIGID CALYX IN WItICH THE BRACHIALS ARE FREE (OR SOMETIMES LOOSELY CONNECTED) ABOVE THE RADIALS. 10 INTERR kDIALS OR INTERBRACHIALS EXCEPT AT THE POSTERIOR SIDE AND BRACHIALS NEVER NORMALLY INCORPORATED IN THE CALYX. PLATES OF THE CUP UNITED BY CLOSE SUTURE. IOUTtI SUBTEGMINAL; FOOD-GROOVES SUPRA TEGMINAL BUT MAY BE CLOSED BY FIXED AMP, ULACRAL PLATES. ARMS WITH OR WITHOUT PINNULES. Of this order by far the most important development resulting from the present collec- tions is in the Calceocrinidae, which in their peculiar anatomy stand out apart from all other crinoids. This has hot onlv furnished the material for the first satisfactory comparison of European and American forms, but also has produced an example of evolutionarv modifi- cation, with the process clearly visible, that is without precedent among the crinoids. This succession involves a long course from the Ordovician to the Lower Carboniferous, and in the somewhat elaborate treatment of the familv which its history has dictated, it has been round necessary to include rather full discussion and illustration based upon those epochs in addition to the Silurian. Another strange form, ]llyelodactylus, with its coiled bilateral stem. has proved to be prolific in instructive material, revealing close relationship with some of the European species. The genus Gissocrimts, hitherto known onlv from Gotland and England, is represented here l)v at least two species, one of them of a type dccidedly new and distinct. Among the Larviformia, the puzzling genus Zophocrim«s is now illustrated more com- pletely than ever belote, and doubtful points of its structure cleared up: and the mysterious .'l[ysticocrinus re-figured and described. The inconspicuous and widelv distributed Pisocrim«s is represented by such a wealth of new material as to require a complete review of the numer- ous species already known. Suborder LARVIFORMIA Wachsmuth and Springer Monocyclic (with exceptions). Clyx above the base consisting only of radials and orals, without anal plates, and usually v,'ithout visible ambulacra; plates imnmvably united by close suture. Arms non-pilmulate, simple and uni- serial. Tegmen when kllOWll consisting chiefly of orals. Family PISOCRINIDAE Angelin Basals threie to rive" radials rive, unequal, r. post. and r. ant. compound, 1. post. and ant. llltlch the largest, 1. ant. reduced. 7 2 SMIT]ISONIAN INSTITUTION PISOCRINUS De ],(oninck _Plates »  -», 24, 2.5 Pisocrinus De Koninck, Bull. Acad. Roy. Belgique, 2me. ser., 4, 1858, p. 93.--Ang elin, Icon. Crin. Suecc., I878, p. 2o.--\Vachsmuth and Springer, Rev. Pal., 3, 1886, p. 172.--S. A. Miller, Jour. Cin. Soc. Nat. Hist., 1879, P. IO; Ara. Geol., 189o, p. 356: 17th Ann. Rep. Dep. Geol., Indiana, 189-'2, P- 636- 642 (adv. sheets, pp. 26-32).--Bather, Crin. Gotl., 1893, P- 21; Treatise on Zool., 3, 19 °°, P" 149, fig. 62.--Jaekel, Zeitschr. d. D. Geol. Gesell, 19oo, p. 482; Phylogenie und System, 1918, p. 89.-- Etheridge, Rec. Australian Mus., 19o4, P. 289 --Zittel-V-astman' Textb. Pal., 1913, p. 2oS.--Thomas, Proc. Iowa Acad. Sci., 22, 1916, p. 29I. -Bassler, Bibliogr. Index, 1915, p. 98o. Trlacrinus Ringueberg (hot Munster), Proc. Acad. Nat. Sci. Phil., 1884. p. 144. Crinoids of vel-y slnall size. 1313 5, unequal; r. p. and r. a. truncate distally and slnaller than the otller three, which are angular above. RR unequal and UlSylnlnetric: 1. post. and ant. large, widest below, and meeting BB by trun- cate faces, the other three RR small, angular below and hot touching BB; r. post. R. transverselv bisected, the large lower seglnent serving as inferradial for it and the r. ant. i. thus forming the RA, which separates theln both froln BB: this plate and the two large RR constitute the greater part of the calyx. :\l-iris 5, unlwanched non-pinnulate, colnposed of verv long brachials beyond the first, which is short" thev spring ri-oin indented facets at the middle of tlle radials bounded bv processes or partitions at either side projecting upward and iuward; the processes are various in form and size, froln low, narrow, rectan- gular, to high, wide and of spear-head shape, that on the posterior side, forlned by the right and left posterior radials, being lower and wider than the others, and curved inward for support of the anal tube. Tube crescentic or triangular in section, reselnbling an arln. Te,o,-lnen arched by 5 solid orals which interlock at tlle tenter, meet closelv at their lateral faces, and COlmect with the radial processes. Stem round, with short columnals, thickened in the lniddle. Surface usually smooth, exceptionally tubercular. (.C, ee generic diagraln, pl. 23, fig. 46.) Genotype. Pisocrinus pihtla De I£onincl« Distribution. Silurian; Gotland, England, America, Australia. Pisocrimfs is a form of cosmopolitan distribution, being round ahnost wherever Silurian strata are exposed, hot only in Europe and America, but also in the antipodes, two species having beeu described from Australia. A characteristic fossil of the \Venlockian beds of England and Sweden. from the former of which it was t]rst described, the genus has been recognized from American rocks in Nev York, Ohio, Indiana, Illinois, Iowa, Missouri and Tennessee, in almost all the subdivisions of the Silurian from the Clinton and Osgood to the Racine dolomite and the Louisville. In some of these areas it is an important fide fossil. Species are numerous, and in some of them iudividuals are abundant. Comparison of Euro- pean and American srecies shows a striking correspondence in some of them, which con- tributes important evidence of a migrational connection bv wav of a northern route between the faunas of northeru Europe and the United States during Silurian epochs. For a full discussion of the relations of Pisocrinus and the literature concerning it, reference should be had to Dr. ]3ather's Crinoidea of Gotland, 8c 3. The parallelism of European and Americma species is recognized, being emphasized bv the statement on page 2 7 PISOCRINIDAE 73 that except for tbe difference in matrix and mode of fossilization he could hOt undertake to discriminate between some of the species from the two continents. This agrees with my own observations ruade wbile assembling a representative series of foreign species for comparison. as is shown bv forms herein illustrated on plate 25. Bather's studies upon the morphology of Pisocrinus were very important, especially in placing upon a logical basis the orientation of the calvx, which had hot theretofore been properly understood. Thus the relation of the peculiar large plate lying underneath the right posterior and right anterior radials as the radianal became clear. He recognized three de- scribed species in the European Silurian, and noted an undescrihed species from Dudley. In America eleven species have heen described, of which at least one is a synonym. Certain of these species are beautifully distinct, so that there is hot the least difficulty in recognizing them, eveu from inferior specimens: such, for example, as P. gc.mniformis and P. baccula, occurring at the saine localitv in the Laurel formation, and P. quinquelobus mad P. tc,:nesseensis of the P, rownsport ; whereas P. canpana is so variable and xvidely distributed tbat some varieties are easilv confused witb other species, and one is inclined to see among them an admixture of European forms. For one of so sma!l and inconspicuous a habitus, this genus pos.esses some remarkablv distinctive characters. In the unequal distribution of radials, it partakes of the sinular type of irregularity xvhich characterises its family, as well as tbe Calceocrinidae and several other monocvclic genera, such as Heterocrinus, Haplocrimts, M,cocrimts, Calillocrimts, etc., in which two of them--and those alwavs the saine, 1. post. and ant.--are simple, larger than the others aud of a different shape, while the other three are trausverseh" divided or nmch re- duced iu size. The projecting processes between the radial facets are peculiar to this and a few other genera having narrow, unbranched arms ; their varyin.,-" shape offers useful specific characters; the projections are often built up about equally from the apposed radials, in which case the interradial suture bisects the process, while in others the division may be unequal, or the projection entirely confined to one of the radials. The inequality and difference in shape of the basals is a character iu which this genus differs from most other crinoids, even from those of its mwa family. The arms are characterized hv a great length of bracbials--an unusuaI feature which is repeated in some of the contemporaneous Calceocrinidae. Tiais fact led S. A. Miller into some curious notions about the brachial appendages of Pisocrinus, be declaring with charac- teristic assertiveness that they vere hot arms, but something else of unknown function for vhich he coined a new terre, " arm blades." The arms varv considerablv in length in different species; in some it seems as if thev vere limited ahnost to a single brachial. vhile in others they extend to a dozen or more. The ventral furrov in some species is broad and deep. fringed with side pieces so large as to produce a considerable resemblance to pinnules (pl. 24, figs. 8, 9)- The structure of the tegmen, which was formerly misunderstood--certain isolated, radi- ately folded, conical plates being supposed to belong to it which we nmv know to be the fused orals of Gaacrim«s--has been ruade clear bv the discovery of two specimens in wbich it is perfectly preserved, consisting of rive closelv apposed orals similar to those of OE,mbathocrinus. The characters available for the discrimination of species are for the most part xvell defined. They are: I. General form of calyx, xvbether a. conical, elougate, or short and wide; b, ovoid, ex- panding upward or contracting: c, globose: d, Iobed or round. In some species these are constant and re|iahle, while in others with a wide range of variation all of the first three may be included. 2. Base. whether a. convex xvith small indented colunm-facet : b, concave, broad and shal- low. or with deep, funnel-shaped pit: c, truncate, with cohunn-facet ahnost to full width. 74 SMITIISONIAN INSTITUTION 3. Basals, whether a, large, visible completely in side viev, or only by points of the larger ones; b, small, hidden at bottom of a deep cavity. 4. Radial facets, whether wide or narrow, plain or dove-tailed. 5- Processes, whether a, low and narrow, straight : b, angular, widening upward or inward; or c, high, spear-head shape. No discussion of the genus tisocrinus wou]d be complete without consideration of the Devonian forms from tbe Eifel described by Mfinster  and Schtfltze " as Triacrimts, in which the arrangement of calyx plates is the same, except that it is said to have onlv three basals instead of rive. This probably holds good for T. altus, but in T. depressus the basals vary from 3 to 5; and in my specimens those with 3 are rather more rare than those with 5- In other ways this species shows a considerable similarity to P. tenwssecnsis. The tri-partite base of the Devonian genus is an evident derivative by fusion from the 5 basals of its Silurian ancestor, and the occasional occurrence of 4 and 5 basals a reversion to tbe older type. I ara giving a series of figures of both species on plate 2 5, showing these facts. The other member of the family, Calycanthocrimts. also from the Devonian, represents a development of the saine plan of radial arrangement from Triacrimts in the direction of the Catillocrinidae, by means of an increased nmnber of arm-bearing segments. In the description of species of Pisocrius the terres " large" and " small " are only relative, all forms of the genus being very small as compared with crinoids generally. The figures on the plates are mostly double size. Pisocrinus gernrniforrnls S. A..liller Platc _ » " figs. r-ga Pisocrim*s gemmi[ormis Millet, J«mr. Cin. Soc. Nat. Hist., 1879, p. 113, pl. 9, figs. 6a-c; 7th Ann. Rep. Jndiana Dep. Geol., 892, p. 6.36, pl. 6, figs. lO-12, 24-25 (adv. sheets, 89, p. 26).--Foerste, Jour. Geol., I9O3, p. 562.--S1ocom, bïeld Columb. Mus., 2, Geol. Ser., 9o8, p. 278, pl. 84, figs. I-4. A small species" diameter of maximum specimen at lower tbird of cup 6 mm., usually much smaller, ranging down to 2. 5 mm. Calyx ovoid, truncate above, contracting at arm-facets; smaller specimens globose. Base broadly rounded, with cavitv for column small, abruptly sunken. BB large, well exposed in side view, where the larger ones reach one third the height of calvx. Radial facets wide; processes low, narrow, rectangular, hot widening inward. Arms short and heavy. Tegmen arched bv 5 interlocking orals, closely bounded bv the short first brachials. One of the two most characteristic species of tbe Lmrel at St. Paul, where it occurs in almndance, mostlv less than 4 mm. in diameter ; the habitus is small, larger specilnens being the exception. The verv low, narrow processes between the facets, coupled with the promi- rient basals, are the distinctive characters. The type o.f the original description in x879 was said to be from the lower part of the Niagara group, in Ripley County, Indiana, and in that of I89i in the ITth Indiana, the type locality was given as Osgood, and the species said to be "now known from Madison and other places in the Niagara group of Indiana." Thus it might bave been derived from the Osgood or Laurel formations. According to Foerste (Jour. Geol., I9o3, p. 562) it extends from the Osgood to Laurel in Tennessee. $1ocom identifies it in the Racine of the Chicago area. but the altered condition of the dolomite speci- mens may prevent a close comparison. It is also reported from tbe Bainbridge limestone of  Beitriige z. Petrefaktenk., 839, p. 3- -" Echin. Eifl. Kalk., 866, p. PI SOCRI N I DAE Ste. Genevieve County, Missouri. As the first American species of Pisocrimts to be de- scribed, tbere is a tendency to identify as P. gemmiformis any small, globose form, which mav in some cases be the younger stage of other species. I have round this to be the case in the Tennessee collections. The one thing certain is that the species is characteristic of the typical Laurel formation. The oral plates are shown in figs. 8, Sa. Hori:on and locality. Laurel formation and perhaps Osgood, Niagaran ; St. Paul, Osgood, Madison, Indiana, and possibly other localities as noted. I have figured a specimen from Gotland, plate 25, figure 13, wbich bas ail the characters of this species. Pisocrinus baccula liller and Gurley Plate 23. figs. 9-*5 Pisocrinus baccula Miller and Gurley, Bull. 7, Illinois St. Mus., 895, p. 79, pl. 5, figs. z3-26. A relatively, large species, maximum specimens 5 mm. high by 8 lnm. ,,vide. Clyx globose to ovoid, widest in lower third, contractin. upwards. RR and RA curving sharply inward, formin.o.q a brad trian