.6H- I i.r PALEONTOLOGY: YOLLTME VIII. _ AN INTRODUCTION TO THE STUDY OP THB GBNKRA Paleozoic Brachiopoda. Part II. II V JAMES HALL, 8TATK OBOLOaiBT AND PAI.^ONT<>IX>OI8T. ASSISTED BT JOHN M. CLARKE. , r ALBANY, N. Y. : CHABLE8 VAN BENTHUYSEN & SONS. 1894. QH [06 V. 50 DEDICATION. To His Excellency, ROSWELL P. FLOWER, Governor of the State of New York : Sir : I have the honor to present to your Excellency a volume of the Natural History of the State, entitled Volume VIII, Part II, Paleontology op New York. This volume, published by authority of the Legislature, is the final one of thirteen in this department of Natural Science, and relates especially to the Class Brachiopoda. Any further investigations which may be made in this science will be published as separate papers or memoirs. The volume is a continuation of Volume VIII, Part I, entitled an Introduc- tion to the Study of the Palaeozoic Brachiopoda ; Part I having been commu- nicated to your Excellency in 1892. The long delay in the publication of the second part is a matter of extreme regret to the author. The objects of this work, as stated in the first part of the volume, were to bring together under one title a summary and revision of the genera of Palaeo- zoic Brachiopoda, including in this revision all the genera which had been pub- lished in the preceding volumes of the Palaeontology of the State, as well as in collateral works. This work has now been accomplished, so far as collections and means of publication have been afforded. In concluding this work I wish to express my most sincere thanks to your Excellency for the liberal and kindly disposition manifested towards this undertaking ; also my grateful acknowledgments to the Legislatures of the State of New York which, in the past, have so liberally responded to the needs of scientific investigation. I have the honor to remain, With great respect. Your obedient servant, JAMES HALL, Albany, N. Y., November 29, 1894. State Geologist and PalcEontologist. TABLE OF CONTENTS. Pase. DEDICATION iii TABLE OF CONTENTS v-vii PREFACE - - ix-xvi II. BRACHIOPODA ARTICULATA (continue) ------ 1 \ SpIRIFER -------------1 Ctrtia ------------- 40 Cyrtina ----- --43 Strinoothtris ------ 47 Spiriferina ------ -51 Amboc(elia ------------ 54 Metaplasia ------ -56 Whitfieldella ------------ 58 Hyattella ---- -61 Datia 62 Hindella 63 Meristina --- 65 Merista ------- 70 Meristella ------ 73 Charionella ------ -78 Pentaoonia ----- -- 80 Camarospira -82 Athyris ------------- 83 Cliothyris ....----90 actinoconchum ------------ 92 Seminula ..---93 Spirioerella - 98 Kayseria --I01 Rbtzia 103 Rhynchospira ---...------ lOo Ptychospira ------------ 112 • Dncites ------------- 113 eumetria - 1'^ acambona ------------- 119 hustedia ------------- 120 Uncinella ---- - 123 vi TABLE OF CONTENTS. BRACHIOPODA ARTICULATA (mntiniud). Pagb. Trkmatospika 124 Pakazyoa .....-....-.- 127 Ahoi'lothec-a 129 CatLoeriRA ..-.. 134 Lbptoorlia - 136 VlTfLIXA .--.. 138 Ajabaia - 141 Ndclbobfira 142 Ctclospira 146 Glaaua 152 ZTampiRA 164 Catazyqa 157 Clixtosella 159 Atrypina ............. 161 Atryi'a 163 Gruenkwaldtia 175 Karpins^kia 176 Rhtncuonella ........... 177^ 178 Protoruyncha 180 Orthorhyxchula -- - 181 Rhtncuotrema 182 Rhtnchotreta ..-■-_ 186 KTENasCHJSMA --.-----..-. 187 Camarot(ec-hia 189 LlORHTNCHUB 193 WiLsoNiA, Uncinulds, Uncindlina, Hypothtris ...... 196 PnoNAx - 202 Eatonia - 204 Cyclorhina -- - 206 Terebkatcloiuea -- 208 Rhtnchofora - 210 Camarophoria 212 tSYNTROPHlA 216 Camarella 219 PARAffTROPHIA 221 Amahtropuia 224 porambomtes 226 Ltcophoria 230 comchidium 231 Pextahkrcs - 236 Barrandella, Pentamerella, Sieberella, Gypidula .... 241 Capellinia 248 TABLE OF CONTENTS. vii BRACHIOPODA ARTICULA-TA {continued). Paqe. Stricklandinia --..-_..... 249 Amphiqenia ------------- 252 Renssell^ria -... 255 Newberria - 261 Centronella, Oriskania, Selenella, R( )Minqerina, Triqeria, Notothyris - 265 scaphiooelia 275 Meoalanterib .----...-.-. 277 Stringocephalcs -._ 282 Cryptonella -......--_.- 286 Dielasma 293 DiELASMINA ...----- .-.. 298 Hemiptyc-hina ----........ 299 ^ Cryptacaxthia 300 Tropidoleptus .-.-...-.... 302 ElCHWALDIA ............ 307 aulacorhynchcs 3h Lyttonia - 313 Oldhamina -- 314 RiCHTHOFEMA ---....----- 315 Supplementary Note on Vitulina .--....-- 317 Evolution op the Genera op the PALisozoic Brachiopoda . - - - 319 Table of Classification -....^.---- 351 Descriptions of New Species .....-.-.. 359 INDEX 371 PLATES AND EXPLANATIONS xxi-lxxxiv E R R ^ T ^ Fig* 1, under Bpirifbb, a HitU Paleontology of N. Y., vol. ii, pp. 66, 261-266, 327, 828, pi. xiii, figs. 2d, 2 r, 3 ; pi. liv, ^ga. 2-6 i pi. Ixxiv, figs. 7-9. 1852. 8piT\fer, V. Robmbr. Kreidebil.iung von Texas, p. 88, pi. xi, fig. 7. 18SS. 8pir\fer, Halu StanBbury's Expl. and Survey of the Valley of the Gi-eat Salt Lake of Utah, p. 410. pi. Iv, fig. S. 18SS. Spir\fer, Owbk. Geol. Survey Wisconsin, Iowa and Minnesota, pp. 585, 586, pi. iii, figs. 1-6, 8; pi. V, figs. 4, 6. 18M. 8pir{fer, Norwood and Pkattbn. Jour. Acad. Nat. Sci. Philadelphia, vol. iii, pp. 72, 73, pi. ix, figs. 2, 3. 185S. Spirifer, Shdmard. Oeol. Survey of Missouri, pp. 202, 203, 216, pi. c, figs. 7, 8. 1866. Spirifer, Hali. Pacific R«ilioa1. vii, figs. 2, 4, 5. 1858. 9pir\fer, DtUhyris, Roqbks. Geology of Pennsylvania, vol. ii, part ii, p. 825, fig. 643 ; p. 826. fig. 650 ; p. 828, figs. 668-670, 673 ; p. 829, fig. 683 ; p. 833, fig. 694. 1868. Spirifer, Shumard. Trans. St. Louis Acad. Sci., vol. i, pp. 292, 293, 390 ; pi. xi, figs. 3, 4. 1869. Spirifer, Hall. Palajonlology of N. Y., vol. iii, pp. 198-205, 419-428, plates xxv, xxvi, xxvii, xx\-iii, xcvi, figs. 7-9 ; pi. xcvii, xcviii, figs. 1-8 ; pis. xcix, c. 1869. Spirifer, Mbkk and Hatdbn. Proc. Acad. Nat. Sci. Philadelphia, vol. iii, second ser., p. 27. 1869. Spirifer, Smumard. Trans. St Louis Acad. Sci., vol. i, p. 391. 1860. Spirifer, Hall. Canadian Naturalist and Geologist, vol. v, p. 145. 1860. Spirifer, Mkbk. Proc. Acad. Nat. Sci. Philadelphia, vol. iv, second ser., pp. 308-310. 1860. Spirifer, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., pp. 71, 82, 94, 111. 1860. Spirifer, Amboecelia, McCuesnbt. New Palaeozoic Fossils, pp. 41-43. 1860. Spir\fer, Swallow. Trans. St. Louis Acad. Sci., vol. i, pp. 641-646. 1860. Spirifer, F. Robmbr. Die silui-ische Fauna des westlichen Tennessee, p. 68, pi. v, fig. 8. 1860. Spir\fer, Emmoks. Manual of Geolog>', p. 151. 1860. Athyris, Billihqs. Canadian Jour., vol. v, new ser., p. 276, figs. 33, 34. 1861. Spirifer, Nbwbkrrt. Ives' Rept. Coloi-ado river of the West, p. 127. 1861. Spirifer, McChbskby. New Palteozoic Fossils, p. 84. 1861. Spirifer, Hall. Ann. Rept. Geol. Survey of Wisconsin, pp. 25, 26. 1861. Spirifer, Billisos. Canadian Jour., vol. vi, new ser., pp. 253, 254, figs. 59-62 ; p. 255, figs. 63, 64 ; p. 266, figs. 65-67 ; p. 257, figs. 68-70 ; p. 258, figs. 71-73 ; p. 260, figs. 74-76 ; p. 261, figs. 77, 78. 1861. Spirifer, Mbbe and Wobthbk. Proc. Acad. Nat. Sci. Philadelphia, vol. v, second ser., p. 143. 1862. Spirifer, Whitb. Proc. Boston Soc. Nat. Hist., vol. ix, p. 24. 1882. Spirifer, Whitb and Whitkibld. Pioc. Boston Soc. Nat. Hist., vol. viii, p. 293. 1862. Spirifer, Wixchbll. Proc. Acad. Nat. Sci. Philadelphia, vol. vi, second ser., pp. 405, 406. 1862. Spirifer, Hall. Geology of Wisconsin, vol. i, p. 69. figs. 5, 6, p. 436. 1862. Delthyrix (Coxbad) Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., pi. xi, fig. 18. 1868. Spirifera, Davidsom. Quai-t Jour. Geol. Soc. London, vol. xix, pp. 170, 171, pi. ix, figs. 7-10. 186S. Spirifer, Athyrit, BiLLisas. Geology of Canada, p. 317, figs. 328, 329 ; p. 372, figs. 391-394 ; p. 373, fig. 898 i p. 386, figs. 422-424 ; p. 957, figs. 455-457 ; p. 960, figs. 465-467. BRACHIOPODA. 3 1863. Spirifer, Swallow. Trans. St. Louis Acad. Sci., vol. ii, pp. 85, 86, 108. 1863. Spirifer, Hall. Ti-ansactions of the Albany Institute, vol. iv, pp. 211, 212. 1863. Spirifer, Billings. Pioc. Portland Soc. Nat. Hist., vol. i, pp. 116, 117, pi. iii, figs. 15-17. 1864. Spirifera (Martinia), Mbbk and Haydkn. Pal. Upper Missouri, pp. 17, 19, 20. 1864. Spirifera, Meek. Palaeontology of California, vol. i, p. 13, pi. ii, fig. 6. 1865. Spirifera, Winchbll. Proc. Acad. Nat. Sci. Philadelphia, vol. ix, second ser., pp. 118, 119. 1865. Spirifera, Shalbr. Bull. Mus. Comparative Zoology, No. iv, p. 70. 1866. Spirifera, Gbi.vitz. Carbon und Dyas in Nebraska, pp. 42, 44, 45, pi. iii, figs. 10, 18. 1866. Spiriftra, Martinia, Wikchbll. Geological Report of the Lower Peninsula of Michigan, pp. 93, 94. 1866. Spirifera, Swallow. Trans. St. Louis Acad. Sci., vol. ii, pp. 408-410. 1866. Spirifera, Billing.s. Catalogue Silurian Fossils of Anticosti, p. 48. 1866. Spirifera, Mbbk and Wortheh. Geol. Survey of Illinois, pp. 155, 298, pi. xiv, fig. 5 ; pi. xxiii, fig. 5. 1866. Spirifera, Hall. Proc. Amei-ican Philosophical Society, vol. x, p. 246. 1867. Spirifera. Hall. Paleontology of N. Y., vol. iv, pp. 186-247, 250-257, 416, 417, plates xxvii, figs. 13-34, xxviii, xxix, xxx, xxxi, xxxii, xxxiii, xxxiv, xxxv, xxxvi, xxxvii, xxxviii, xxxviii A, xxxix *, xxxix, xl, xli, xlii, Ixiii, figs. 6-13, 14. 1867. Spirifera, Swallow. Trans. St. Louis Acad. Sci., vol. ii. 1867. Spirifera, Hall. Twentieth Report N. Y. Stale Cab. Nat. History, pp. 251, 370, 371, pi. xiii, figs. 5-11, 14, 15. 1868. Spiryera (Martinia), Mbbk. Trans. Chicago Acad. Sci., vol. i, pp. 101-107, pi. xiv, tigs. 1-3, 9, 12. 1868. Spiriftra (Martinia), McCubsmbt. Trans. Chicago Acad. Sci., vol. i, pp. 34-36, pi. i, figs. 3, 4 ; pi. vi, tig. 5 ; pi. viii, tig. 3. 1868. Spirifera, Mbbk and Wobthk.v. Geol. Survey of Illinois, vol. iii, pp. 298, 384, 399, 414, 415, 434, 443, pi. vii, fig. 9 ; pi. viii, figs. 5-7 ; pi. x, figs. 1, 2, 5 ; pi. xiii, fig. 8. 1869. Spirifera, Todla. Sitzungsb. d. k. k. Akad. Wissen. zu Wien, vol. lix, p. 3, pi. i, figs. 2-4. 1870. Spirifera, Winchbll. Proc. American Philosophical Soc, vol. xii, pp. 245, 251, 252. 1870. Spirifera, Mbbk and Worthbn. Proc. Acatl. Nat. Sci. Philadelphia, vol. xiv, sec. ser., p. 36. 1870. Spirifera (Trigonotreta), Mbbk. Pi'OC. Acad. Nat. Sci. Philadelphia, vol. xiv, sec. ser., p. 60. 1871. Spirifera (Trigonotreta), Mbbk. Proc. Acad. Nat. Sci. Philadelphia, vol. xv, sec. ser., p. 179. 1872. Spirifera (Martinia), Mbbk. Hayden's Rept. U. S. Geological Survey of Nebraska, pp. 183, 184, pi. ii, fig. 3 ; pi. iv, fig. 4 ; pi. vi, fig. 12 ; pi. viii, figs. 2, 15. 1872. Spirifera, Hall and Whitfield. Twenty-fourth Rept. N. Y. State Cab. Nat. Hist., p. 182. 1873. Spirifera, Hall and Whitkibld. Twenty-third Rept. N. Y. State Cab. Nat. Hist., pp. 237, 238, pi. xi, figa. 12-24. 1873. Spirifera, Mbbk. Sixth Ann. Rept. U. 8. Geol. Survey of the Terr., pp. 466, 470. 1873. Spirifera, Mbbk and Worthbk. Geological Survey of Illinois, vol. v, pp. 572, 573, pi. xxv, figs. 5, 7. 1874. Spirifera, Rathbo.v. Bull. Buffalo Soc. Nat. Sci., vol. i, pp. 237, 239, 241, pi. viii, figs. 1-9, 11, 13-21 J pi. ix., fig. 22. 1874. Spirifera (Marti7iia), Derby. Bull. Coraell Univemty, vol. i, pp. 13, 15, 16, 19, plates i-v, viii, ix. 1874. Alhyrisl, Spiriferina, NiCHOLSOif. Paleontology of Province of Ontario, pp. 82, 88. 1874. Spirifera, Billinos. Palteozoic Fossils, vol. ii, pp. 44, 45, 47, pi. iii, tig. 8 ; pi. iii A, figs. 3, 5. 1875. Spirifera, Meek. Paleontology of Ohio, vol. ii, pp. 280, 290, 329, pi. xiv, tigs. 5, 8 ; pi. xix, tig. 14. 1875. Spirifera, White. Wheeler's Expl. and Survey West of the 100th Meridian, vol. iv, pp. 86, 88, 90, 132-136, pi. v, figs. 7, 8, 10 ; pi. x, figs. 1-3 ; pi. xi, fig. 9. 1875. Spirifera, Mbbk and Worthbk. Geol. Survey of Illinois, vol. vi, pp. 521, 523, pi. xxx, figs. 1-3. 1875. Spirifera, Hall and Whitkibld. Twenty-seventh Rept. N. Y. State Cab. Nat. History, pi. ix, figs. 11-13, 17, 18. PALEONTOLOGY OF NEW YORK. 1876. afbiftra, Mb««. Sim|>8oii'H Rej)!. Expl. Great Basin of the Terr, of DUh, pp. 345-347, 361, 888, pi. i, fltrs. 1, 4, 5 ; pi. ii, tgn. 3. 5. 1876. Spkr^era, Dbkbt. Bull. Mua. Comparative Zoolojcy, vol. iii, p. 279. 1876. S^r\fmh Mbu. Bull. U. 8. Geol. Survey of the Terr., vol. ii, p. 355, pi. i, fig. 3. 1877. 8fir^tra, Hall and Whitkikld. King's D. 8. Geol. Expl. Fortieth Parallel, vol. iv, pp. 264, 256, 2«St. 270. pi. iv, figs. 6-8 ; pi. v, figs. 13-16, 17, 18. 1877. 8fir\ftra (Trigonotnta), Mkbk. King's U. 8. Geol. Expl. Fortieth Parallel, vol. iv, pp. 39-46, 88. 90, 91. pi. i, fig. 9 ; pi. iii, figs. 1, 3, 6 ; pi. iv, fig. 4 ; pi. ix, figs. 1, 2, 6. 1878. Spbifera, Dawsok. Acadian Geology, thinl ed., p. 292, fig. 91 ; p. 291, fig. 89; pp. 301, 499, fig. 176 ; pp. 59ti, 897. 1878. Spir\feTa, BrHBRiixiB. Quart. Journal GteoX. Society London, vol. xxxiv, pp. 628, 629, 633, 634, pi. XXV, fig. 6 ; pi. xxix, figs. 1, 2. 1878. 9pir\fera, Millbk. Pitk:. Daven|K>rt Acad. Sci., p. 222. 187». Spb^era, Hall. Twenty-eighth Repl. N. Y. State Mus. Nat. History, pp. 166, 167, pi. xxiv, figs. 1-30. 1879. Sp'uifera, Ratubdw. Proc. Boston Soc. Naf. HisU, vol. xx, pp. 25-30. 187S. Spir\fera, Oawfoh. Canadian Naturalist and Geologist, vol. ix, second ser., p. 3. 1880. ((plr\fer€i, Whitk. Second Ann. Rept. Indiana Bureau of Statistics and Geol., pp. 497, 603, 604, 517, plate iii, figs. 5, 6 ; pi. iv, ligs. 1-5, 10, 11 ; pi. viii. fig. 3. 1880. Spirlfera, Williams. American Journal of Science, vol. xx, p. 456. 1881. Splr\ftra {MarttHia), Williams. Annals N. Y. Acad. Sci., vol. ii. 1881. Spitifera, Millbr. Jour. Cincinnati Soc. Nat. Hist., vol. iv, pp. 2, 314, pi. vii, figs. 9, 10. 1881. Spiiifera, Whitb. Tenth Rept. SUte Geol. of Indiana, pp. 129, 135, 136, 149, pi. iii, figs. 5, 6 ; pi. iv, figs. 1-5 ; i>l. viii, fig. 3. 1881. Spiryrra (Marliiiia), Whitk. Wheeler's Expl. Survey west of the 100 Meridian, vol. iii, Appen- dix, i>. xil. 188S. 9pir\fera, Wuitvibld. Bull. American Mus. Nat. Hist., vol. i, p. 47, pi. vi, figs. 13-16; 1883. Sphifetxi, t Spiriferina, Whitkikld. Geol. Wisconsin, vol. iv, pp. 287, 328-331, pi. xvii, figs. 1, 2 ; pi. XXV, figs. 22-28 ; pi. xxvi, figs, 1-4. 1883. Spir\fera, Hall. Eleventh Rept. State Geologist Indiana, pp. 294-297, pi, xxiv, figs. 1-20, 30 ; pi. xxvii, figs. 8, 9. 1883. ISpirifera {Mattinia), Whitb. Eleventh Rept. Slate Geol. Indiana, p. 372, pi. xlii, figs. 4-6. 1883. ecie8 deHcribeil as Spir\fa- zic-zae. Hall, in 1843. The same specific name was, curiously enough, used by F. Rokmkb, in Ihe same year, for a quite distinct Devonian Spiriper, and D'Orbiqny, in 1850, proposed for the Aineriuan sitecles the name above used. tSee observations on the ^nera SYRiHaoTHTBis, Ctrtima and Spirifbrina. BRACHIOPODA. 17 Mr. Davidson has referred tAvo Devonian species to Spiriferina, S. cristata Schlotheim, var. octoplicata, and S. insculpta, Phillips ( ? ), both of which are described as having a punctate structure. It is not known, however, whether in these early forms the loop has attained its ultimate development; we might expect to find it with its lateral branches discrete as in the true Spirifers. The species of this septate section have, so far as known, the surface of the concentric lamellae covered with fine radiating striae which were evidently not continued into spines or fimbriae. Among the forms which are referred to the genus Spiriferina nearly every variation of surface ornament is to be found except this. The Carboniferous species, like S. Kmtuckiensis and S. solidirostris, which resemble very closely in other respects these septate lamellose Spirifers, are fimbriated. 'I. Aseptati. Those without a median septum in the pedicle-valve. These species are more abundantly plicated, often much more extended on the hinge than in the septate group. The lamellae are without radial striations. The Aseptati group themselves naturally about two type-forms, the first, (a), Spirifer mucronatus, Conrad, an alate, multiplicate shell with a single low plication in the sinus and a corresponding depression on the median fold; the other, (b), Spirifer submucronatm, Hall, in which the fold and sinus are not plicate. Of these subdivisions the latter was the first to appear in the American Palaeozoic, and is represented by S. submucronatus, and S. Cumberlandia, Hall, of the Oriskany sandstone of Maryland, S. macrus. Hall, S. gregarim, Clapp, and an undescribed species from the Upper Helderberg group. Spirifer gregarim is of interest in having a high area, a rather short hinge, and in assuming some of the characters of the group of the Ostiolati in its internal umbonal callosities. The Mucronatus-type does not appear earlier than the Hamilton fauna, where it is represented by iS. mucronatus, S. segmentus, Hall, S. bimesialis, Hall, S. subat- tenuatus, Hall, S. varicosus, Conrad. III. Fimbriati. Typical examples, Spirifer fimbriatus, Conrad, S. lineatus, Martin, S. arredus. Hall. (la) 1842. OHhis, Vanuxkm. Geology of N. Y. ; Rept. 'ITiird Dist., p. 112, dg. 1. (16) 1842. Orihig, Vahuxkm. Geology of N. Y. ; Rept. Third Dist., pp. 91, 94. 18 PALEONTOLOGY OF NEW YORK. (i) 184S. (>•) 1848. (la) IMS. (16) 1848. (!•) 1848. (I«) 1849. (la) 18S). (It) 1853. (8) 18S3. (la) 1857. (S) 18M. (»«) 859. DdtMyrU, Co»RiD. Jour. Acad. Nat. 8ci. Philadelphia, vol. vili, p. 263. OrtkUt (DfUhj/rit). Hall. Geology of N. Y. ; Kept. Fourth Dist., p. 142, fig. 1. DelUgrU, Hall. Geology of N Y. j Rept. Fourth Dial., p. 105, fig. 3; p. 171, fig. 5. DdtMfrU, Hall. (loology of N. Y. ; Rept. Fourth Dist., p. 208. fig. 10 ; p. 346, fig. 1. SjAr\fer, Caotklsad. Essiai BurleSystimeSilur. de I'Amer. Septeiitr., p. 41, pl.xii, figs. 1,2. Spir^fer, Hall. American Journal of Science, vol. xx, p. 228. Spirifer, Hall. Pala«ontology of N. Y., vol. ii, p. 262, pi. liv, figs. 3o-*; p. 328, pi. Ixxiv, figs. 9a-A. Spirifer. Hall. Paleontology of N. Y., vol. ii, p. 263, pl. liv. fig. 4. Splr\fer, Swallow. Ti-ans. St. Louis Acad. Science, vol. ii, p. 86. Spirifer. Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., pp. 58, 62. Spirifer, Hall. Geol. Survey Iowa, vol. i, pt. ii, p. 606, pl. iv, figs. 6o-e; p. 645, pl. xx, fig. 4 ; p. 705, pl. xxvii, fig. 4. Spiiifrr, Hall. Palieonlology of N. Y., vol. iii, p. 420. pl. xcvi, figs. 8 a-e ; p. 422, pl. xcvii, figs, la-h, 2o-i; p. 205, pl. xxviii, figs. 4 a-e; p. 199, pl. xxv, figs. lo-«; p. 308, pl. xxviii, figs. 2a-/; p. 198, pl. viii, figs. 17-23. Spiri/rr, Halu Palaeontology of N. Y., vol. iii, p. 203, pl. xxviii, fig. 1. Si>ir\fer, McChbsicbv. New Palaeozoic Fossils, p. 43. tipirifera, Hillijiiib. Canap. 10, 14. 18.'>2. Spirifer, Owbk. Geol. Survey Wisconsin, Iowa and Minnesota, p. 586, pi. iii, figs. 2, 6; p. 585, pi. iii, figs. 8, 4, 8. 1857. Spiriftr, Hail. Tenth Ann. Rept. N. Y. Stale Cab. Nat. Hist , pp. 128, 129, 132, 135, 154, 155, 156, l!)8, 161, 163, 164. 1858. Delthyris, Roubks. Geol. Survey Pennsylvania, vol. ii, p. 828; figs. 669, 670. 1868. Spirifer, Hali. Geol. Survey Iowa, vol. i, pt. ii, p. 508, pi. iv, fig. 7 ; p. 509, pi. iv, tig. 8 ; p. 510, pi. v, fig. 1 ; p. 520, pi. vii, fig. 7. 1863. Spir\fera, Billings. Geology of Canada, p. 386, figs. 422o, 6. 1867. Spirifera,VlAU.. Palspontology of N. Y., vol. iv, p. 197, pi. xxix, figs. 1-8 ; p. 198, i>l. xxiv, figs. 9-18; p. 209, pi. xxxi, figs 14-19; p. 211, pi. xxxi, figs. 11-13, 20-30; p. 220, pi. xxviii, figs. 12-16 ; p. 223, pi. xxxvi, figs. 1-13 ; p. 226, pi. xxxvii, figs. 10-20; p. 227, pi xxxviii, figs. 1-25; pi. xxxviii*, figs. 12-18; p. 2.S0, pi. xxxviiia, figs. 23-32 ; p. 234, pi. xxxv, fig. 24 ; p. 292, pi. xxx, figs. 16-20. 1868. Spirifera, Mbkk and Wobtubn. Geol. Survey Illinois, vol. iii, p 433, pi. xiii, fig. 8. 1868. Spirifer, Mbkk and Worthbn. Geol. Survey Illinois, vol. iii, p. 414, plate x, fig. 1. 1878. Sjnrifera, Millkr. Pi-oc. Davenport Acad. Nat. Sci., p. 222. 1880. Spirifera, Wiiitk. Second Ann. Rept. Bureau Stat, and Geol. Indiana, p. 503, pi. iv, figs. 1-3; p. 504, pi. iv, figs. 4, 5. 1881. Spirifera, Whitb. Tenth Ann. Rept. State Geologist Indiana, p. 135, pi. iv, figs. 1-3 ; p. 136, pi. iv, figs. 4. 5. 1889. Spirifera (CyHina), Whitkibld. Geol. Wisconsin, vol. iv, p. 329, pi. xxv, figs. 25, 26 ; p. 329, pi. xxvi, fig. 3; p. 330, pi. xxvi, fig. 4 ; p. 331, pi. xxvi, figs. 1, 2. 1883. Spirifera, Calvih. American Journal of Science, vol. xxv, p. 433. 1884. Spirifera, Walcott. Palajontology of the Eureka District, p. 137, pi. xiv, fig. 10. 1885. Spirifera. Clarkb. Bull. No. 16, U. 8. Geol. Survey, p. 31, pi. iii, fig. 12. 1888. Spirifera, Calviw. Bull. Laboratories State Univei-sity Iowa, p. 19. 1889. Spirifera, NBrtBLROTa. Kentucky Fossil Shells, p. 105, pi. viii, figs. 1-8 ; p. 107, pi. ix, figs. 1-7 ; p. 11.1, pi. vi, figs. 1-7, 9, 11-17; p. 117, pi. vi, figs. 8, 10, 18-20; p. 123, pi. xi, figs. 1-5 ; p. 125, pi. xxvi, figs. 2-5 ; p. 126, pi. vii, figs. 1-10. BRACHIOPODA. 29 Forms with the median fold and sinus without plications. These species, in the degree of plication of the sides and the development of the muscular scars, closely resemble the members of the foregoing group. As a rule, the Ostiolati are stouter shells, shorter on the hinge and more ventri- cose than the Aperturati ; their surface is frequently ornamented with fine granules or interrupted radiating striae, and in some instances this linear sculpture is so pronounced (e. g. S. Parryanus, Hall, S. Macbridii, Calvin) as to suggest a derivation from the multiplicate members of Radiati. The cardinal process is developed as a broad, thin, spreading plate, crossed longitudinally by numerous linear depressions ; a feature which is progressively developed from the earlier members of the group toward the syringothyroids. There appears to be no substantial basis for a subordinate grouping of these species ; they were evidently but slightly susceptible to variations in exterior characters. While the cardinal area is sometimes erect and broad, and at others more or less arched, these differences occur within specific limits. Many of the middle Devonian representatives bear a low median sulcus on the fold, which may be accompanied by a broad, very faint, indistinct plication apparent only near the anterior margin of the sinus. Such are S. Oweni, Hall, S. granulosus, Conrad (^ S. granuliferus, Hall), . 219. 1888. Syringothyris, Hbrrick. Bulletin Denison Univei-sity, vol. iii, p. 41, pi. i, fig. 7; pi. ii, fig. 17 ; pi. v, figs. 4-7 ; vol. iv, p. 14. 1889. Syringothyris, Simpson. Trans. American Philosophical Society, p. 440, fig. 5 ; p. 441, fig. 6. 1890. Syringothyris, Schdchbrt. Ninth Rep. N. Y. State Geologist, pp. 28-37. Shells spiriferoid, usually large, with erect cardinal area and broad, multipli- cate lateral slopes. Fold and sinus generally non-plicate. In the pedicle-valve the delthyrium is covered by a convex, imperforate plate, which is frequently absent. The dental lamellae, more or less strongly developed, rest on the bot- tom of the valve, and at their anterior extremities are produced about the broad diductor impressions. They are united beneath the deltidium by a transverse plate arising from a testaceous callosity in the apex of the delthy- rium. This plate is formed by the deposition of accretions to the margins of the delthyrium, which unite in the median line, the union being marked by a raised line less distinct on the upper than on the under side of the plate. From just within the lateral margins and on the inner side of the plate two lamellar 48 PALMOUTOLOGY OF NEW YORK. processes are given off, which are curled toward each other with some irregu- larity, not meeting except where coalesced with the apical callosity, forming a tube which is split along its inner surface. This tube is adherent to the trans- verse plate as far as the latter extends, and is frequently produced beyond its termination. Muscular scars as in Spirifer, their anterior portion being divided by a short median septum which is an extension from the apical calcareous deposit. The brachiiil valve is spiriferoid in all internal details. The cardinal process is broad, multistriate and supported by a short median thickening. The spirals are large, the primary lamellae bearing a pair of short, discrete spinous processes which represent the loop. The shell structure is more or less distinctly and abundantly punctate. It is probable that these punctae perforate the epidermal layer and extend to the inner laminae of the shell. The exterior is usually ^"* *°- ^"* p;''"*'^ '*"'«"»' <"■ •^ Syringoihyns typa. covered with a finely textile ornament which has been compared, in appearance, to " twilled cloth." Type, Syiingothyris typa, Winchell. Burlington limestone. The relations of this genus to the Spirifers with smooth fold and sinus {Osti- olati) have already been adverted to at some length. In view of the existence of at least one punctated species of Spirifee (S. plenus, Hall) in which the trans- verse plate and split tube of Syringothyris are not present, and of gradational conditions in respect to other points of structure, which have been noticed, it is quite safe to assume that this peculiar group of forms is an outcome from normal development with variation along that spiriferoid line. The extrava- gant structure within the delthyrium, termed the split tube, may be regarded as the extreme manifestation of a tendency in all the later spiriferoids with plicated exterior to excessive secretion of testaceous matter in this region. Dr. Kino, in 1868,* claimed to have found traces of this tube or canaliferous plate in a rudimentary condition in several species of Spibifer, e. g., S. striatus. * AniiMls Md Kagnane of Natural Histoiy, Fourth aeries, vol. ii, p. 18. BRACHIOPODA. 49 S. disjundus. These observations have not yet been verified, but it would be reasonable to expect such phenomena even among Spirifers not belonging to the group of Ostiolati. Yet here, as in so many other generic groups of the brachiopods, it is the extreme development of a given peculiarity which serves as a basis of generic distinction from forms possessing the same character in a state of incipiency. What may have been the function of this organ in the physiology of the animal is still a subject for speculation. King suggested that it might have been a base of attachment for the pedicle-muscles. The pedicle, however, was probably atrophied in the mature condition of these shells ; at least all means of egress were obstructed, except beneath the deltidium. There is no reason from analogy for assuming that the pedicle ever passed through this aperture but in case it was thus extruded, Dr. King's supposition seems a plausible one. If, however, the pedicle was atrophied from the closure of its normal channel nearer the beak, this calcareous tube may have been an exudation encysting this functionless organ. In one interesting species from the earliest of the Carboniferous faunas, S. Herricki, Schuchert, there is a solid process in place of a tube benesith the transverse plate, which is extended to the bottom of the valve, thus forming a septum supporting the transverse plate, and exhibiting in a striking manner an inclination toward the internal structure of Spiriferina. The divergent views of King and Carpenter in regard to the punctation of the shell in S. cuspidalus are well known, and the discussions may be found principally in the Annals and Magazine of Natural History, and the Geological Magazine for the years 1867 and 1868.* The late F B. Meek was the first to demonstratef that the shell substance in S. cuspidatus is punctate, and probably all the species possessed of a transverse plate and split tube have this shell structure. This punctation has been de- scribed as " patchy ; " it is better developed or better retained in some parts of • The student may ateo be referred to Dr. Cabpbntbb's earlier observations in his report to the Bidtish Association, 1844, " On the Microscopic Structure of Shells," and to his treatise in Davidson's Intioduction, " On the Intimate Structure of the Shells of the Brachiopoda." 1852. t Proc. Acatlemy of Natui-al Sciences, Phila., vol. ix, second ser., p. 275. 1865. 50 PALJEONTOLOGY OF NEW YORK. the shell than in others, a variation which may be due to the easy destruction of the delicate pores which are exceedingly small and much .finer than in Spiriperina, Cyrtina, and the terebratuloids. Attention, however, may be directed to an interesting species from the Cho- teau limestone of Cooper county, Missouri, small in size, cyrtiniform in figure, with a highly and coarsely punctate shell.* While regarding Svringothyris as an outcome from Spirifer along the line of the Ostiolati, the genus contains an occasional species which is isomorphic with the Aperturati. Such, for example, are the S. Randalli, Simpson, from the Waverly faunas of eastern Pennsylvania, and the S. distans, McCoy, of the Coal Measures of Great Britain and Belgium. The type species of Syringothvris was named by Professor Winchell, Syringothyris typa, and was derived from the Burlington limestone. Drs. King and Davidson both regarded this fossil identical with Spirifer cuspidatus, Martin, and they have been followed by Meek, Walcott and Herrick, but Schochert f has pointed out differences which may serve to keep the European and Amer- ican forms distinct. The fact that the species Spirifer Carteri, Hall, from the Waverly sandstones of Ohio, is a Syringothyris has been long known. Swallow's Spirifer {Cyrlia ?) Hannibalensis, from the Choteau limestone, is a smaller form of the same specific type as S. typa. In the Waverly fauna of Pennsylvania occur the species described by Mr. G. B. Simpson as S. Randalli and S. angulata.X In the development of the same fauna in Ohio, and in the Keokuk group of Indiana, Illinois and Iowa, S. texta. Hall, and its allies are not uncommon species {Spirifer texttis, Hall, S. subcuspi- datus. Hall, S. propinquus. Hall). *Thia is evidently an undescribed shell, and as it is an impoi-tant one for our purposes the name SyrinffothyrU MUtouri is proposed. Its highly punctate shell, its size and form, all indicate a deviation toward Cybtika, while the canalifoi-m transvei'se plate is developed as a very delicate structure. For a fuller description of the sjiecies see the supplement to this volume. t On Syringothyris, Winchell, and its American species ; RepoH of the N. Y. State Geologist for 1889, p. 380. 1890. J Proc. American Philoso])hical Society, vol. xvi, 1889, p. 435. These were described as 8. Randalli and var angulata, but as the formei' possesses a plicate fold and sinus and in the latter the fold and sinus ■re amootb, it will be better to regard them as distinct species. BRACHIOPODA. 51 Mr. ScHUCHERT h ot Spiryerina Km- Shell substance strongly punctate tnrougliout. tuctimsis. suumard. (o Type, Terebratulites rostratus, Schlotheim. Lias. This name is currently allowed to cover a large number of species presenting the most extreme variations in exterior characters and some important inter- nal differences. The type of the genus is a form upon whose surface the plications are obsolescent and whose epidermis is covered with closely matted spinules ; the median septum is discrete from the dental lamellae, and the loop is a transverse band with a slight upward curve. Recent writers on the Triassic bnichiopods, however, still strain the genus to include species in which the septum unites with and supports the convergent dental lamellae, forming the structure characterizing the interior of Cyrtina.* Among the palaeozoic species referred to Spiriferina, the prevailing expres- sion is a strongly plicated exterior with well marked fold and sinus. The shells are usually of small size, and though occasionally with a spiniferous exterior, as in S. spinosa, the usual ornamentation consists of concentric lam- ellae of growth, the surface of which is radially striated and probably minutely fimbriate. The development of the median septum in these species is never 8o extreme as in S. rostrata and the Liassic forms. * See page 45 of this volume. BRACHIOPODA. 53 The accompanying figure of S. Walcotti, Sow- erby, shows the great elevation of this wall, and the broad scars of the adductor muscles upon its lateral faces. This specimen indicates how im- portant are the changes in the anatomy of the animal, resulting from, or productive of this median septum. The older species have furnished no direct evidence of similar muscular attach- fig. 42. SpMferina fTaicoWi, Soworby; ahowingmus- ment, but there is no reason for doubting its cuiar scai son waiis of median septum of ° podiclevalve. (c.) existence wherever such a septum is found. As far as observed, the loop of the palaeozoic species is slightly different from that of the later members of the genus, and resembles that of Cyrtina, the lateral portions converging upward, between the spiral coils, and uniting in a slight anterior extension. The spiral ribbon is spiniferous in S. rostrata, but usually smooth in the Carboniferous species. In S. spinosa, and probably in other species, there is a solid calcareous deposition in the umbonal cavity of the pedicle-valve, filling the interspaces between the dental lamellae and the median septum, not constituting a union of the three plates as in Cyrtina, but forming a secretion analogous to that found in the syringothyroid Spirifers, and to the transverse plate in Syringothyris itself Both the palaeozoic and Liassic species have broad crura, a faint elevated median ridge in the brachial valve, and a pair of divergent ridges lying on the surface of the first internal plications, extending fully, or more than one-half the length of the valve, and ending abruptly; probably the external fulcra of the adductor muscles. It has already been observed that the derivation of the generic characters of this genus has been from the lamellose-septate Spirifers whose inception dates from the faunas of the Upper Silurian. Though none of these Silurian and Devonian species, in the American faunas, developed a punctate shell structure, they usually bear the lamellose, often radially striated exterior, prevailing among the Spiriferinas of the Carboniferous. Mr. Davidson has described two of these lamellose species from the Devonian, which have a strongly punctated 54 PALEONTOLOGY OF NEW YORK. sliell, Spiriferim cristata, Schlotheira, var. odoplicata and S. insculpta* in which it has not been conclusively shown that the median septum exists, though this is a legitimate inference. The gradual assumption of the punctated structure is not so clearly defined among these forms as in the syringothyroid line of development, although one species, the Spirifer transversus, McChesney, from the Chester limestone, is a septate shell in which punctation is but feebly and sparsely developed. The American species which may be referred to Spiriferina are few. The Spirifer solidirostris, White, of the Kinderhook group, is a septate- lamellose shell, but the specimens we have examined do not evince punctation. Spiriferina spinosa, Norwood and Pratten, and S. transversa, McChesney, of the Chester (Kaskaskia) limestone, S. subelliptica, McChesney, of the Keokuk group ; S. Ken- tuckiensis, Shumard, and var. propatula, Swallow, and S. spinosa, var. campestris. White, of the Coal Measures, are characteristic representatives. The forms which have been described as S. Billingsi, Shumard, S. binacuta and S. Clarksvillensis, Winchell, and iS. subtexta, White, have not come under our observation. It should be remarked that Walcott has regarded f S Kentuckensis and var. propa- tula, and S. spinosa as synonyms of Spiriferina cristata (Schlotheim), Davidson. Genus AMBOCCELIA, Hall. 1860. PLATE XXXIX. 1842. OrttiU, CoNBAD. Journal Acad. Nat. Sci. Philailelphia, vol. viii, p. 264. 1848. OrOiis, Hall. Gteology of N. Y. ; Kept. Fourth Dist., p. 180, fig. 8 ; p. 267, fig. 5. 1846. Orthu, RonxoLT. Bull. 8oc. Qfiol. de France, sec. ser., vol. iv, p. 322, pi. iii, fig. 8. 1857. Orthif, Hall. Tenth Kept. N. Y. State Cab. Nat. Hist., p. 167, figs. 1-3. 1860. Amboatlia, Hall. Thirteenth Kept. N.Y. State Cab. Nat. Hist., p. 71, figs. l-3jp.72,fig8.4-6;p.81. 1862. Amboaelia (Spirifer f),yfHnH. Proc. Boston Soc. Nat. Hist., vol. ix, p. 26. 1864. Amboccdia, Mbbk and Hattdbn. Palaeontology of the Upper Missouri, p. 20. 1867. Amboatlia, Hall. Paleontology of N. Y., vol. iv, pp. 258-262, pi. xliv, figs. 1-26. 1883. Amboatlia, Clatpolb. Proc American Philosojihical Society, vol. xxi, p. 232. 1887. Amboatlia, (Ehlsbt. Bull, de la Soc. d'Etudea Scientif. d'Angers, p. 6, pi. v. figs. 11-16. 1889. Amiocalia. Nbttblkoth. Kentucky Fossil Shells, pp. 8S, 86, pi. xvii, figs. 25, 26. Diagnosis. Shells small, concavo-, or plano-convex. Marginal outline nearly semicircular. Hinge-line long and straight, its length nearly or quite equaling the greatest transverse diameter of the shell. • Devonian Brachiopoda, pp. 46, 48, pi. iv, figs. 11-17. t Palsontology of the Eureka District, p. 218. 1884. BRACHIOPODA. 55 Pedicle-valve greatly elevated ; umbo arched and incurved ; with a narrow median groove which becomes fainter or disappears towards the anterior mar- gin. Cardinal area well defined and arched; divided medially by an open delthyrium whose lateral margins bear incomplete deltidial plates. Teeth prom- inent, erect, strongly recurved at the tips ; not supported by dental plates. Muscular area quite restricted, consisting of narrow, elongate diductors, enclosing an almost linear adductor. The entire area is sometimes divided by a faint median ridge. The interior surface about the muscular area is strongly pitted. Brachial valve convex at the beak, becoming depressed over the pallial re- gion and reflexed near the margin. Cardinal area comparatively broad and standing at nearly right angles to the area of the opposite valve. Delthyrium open, the deltidial covering* attaining the same degree of development as in the pedicle-valve. Cardinal process narrow and much elongated, resting on the bottom of the valve except at its posterior extremity which is simply bifurcated. Crural plates erect, parallel ; taking their origin in the deltidial plates and ex- tending about one-fourth the distance across the valve. The spirals are attached by long crura, the ribbon making a few volutions only, thus forming loose coils, directed laterally. The loop has apparently the same incipient condition of development as in Spirifer. According to (Ehlert,! the spiral ribbon bears spinules on its outer margins. Muscular impressions anterior and composed of four well defined adductor scars. Surface smooth or with fine concentric striae crossed by indistinct radiating lines ; rarely spinous. Shell substance fibrous, impunctate. Type, Orthis umbonata, Conrad. Hamilton group. Observations. — The external characters of the Devonian forms of Amboc(elia ally it to Martinia, and there is little doubt that the finely punctured epidermal layer is common to both. The structure of the interior, however, is so unlike that of Spirifer, in its elongate and simple cardinal process, long, parallel, erect crural plates and anterior muscular scars in the brachial valve, that the generic value of the group is beyond question. The type of structure is essentially ♦ CMlidium, Beechep. t Bulletin de la Society d'Etudes Scientifiques d' Angers, 1887 ; Brachiopodes du Devonien de I'Ouest de la France, p. 6, pl. v, Hg. 12. 56 PALEONTOLOGY OF NEW YORK. Devoninn. In America, Amboccelia umbonata appears in the Corniferous lime- stone, and its existence is continued under more favorable conditions for devel- opment in tlie various faunas of the Hamilton group. In the latter faunas is also a larger form which has been described as A. praumbona, Hall, and in the Chemung group A. umbonata var. gregaria, Hall, is a very abundant shell. The Orthis umbonata was identified in the Devonian of western France (Gahard) by Marie Rouaclt as early as 1851,* and has been redescribed and figured by (Ehlert in the work already cited. There also occurs in the Hamilton shales of western New York a species with spinous exterior {A. spinosa, sp. nov.) ; and in the final appearance of Amboc(EL1a in the Coal Measures, where it is represented by the Spirifer plano- convexus, Shumard, the same condition of exterior occurs. In the latter, how- ever, the surface spines are usually lost, the exterior appearing as in the Devonian species though showing the fine punctation or reticulation of the epidermal shell layer. Genus METAPLASIA, nov. gen. PLATE XXXIX. This name is proposed for the little shell described in 1859 as Spirifer pyxi- datus, Hall.f While it possesses a general spiriferoid aspect in outline, the structure of the hinge and deltidium, the pedicle-valve is the more convex and bears a broad fold, while the brachial valve is fiat or slightly convex over the lateral extremities and depressed medially by a broad sinus. This reversal of the relative position of the fold and sinus is accompanied by some other peculiarities. The teeth are stout and unsupported by lamellae ; the posterior extremities of the diductor impressions in the pedicle-valve are deeply impressed and sepa- rated by a short, thick septum. Anteriorly the muscular area is less clearly defined; from its distal margin diverge two ridges which were probably of vascular origin, and a few radiating furrows of similar character are seen on the lateral portions of the valve. * BuU. Soc. G6ol. de France, 2nd ser., t. viii, p, 323. t Paleontology of New York, vol. iii, p. 428, pi. c, figs. 9-12. BRACHIOPODA. 57 In the brachial valve the cardinal process is quite prominently developed and is distinctly bilobed. The socket walls are elevated and recurved ; ante- riorly they are produced into short crural bases which are not free, but rest upon the bottom of the valve. The muscular area is narrow and elongate, and consists of a pair of central adductor scars embraced posteriorly by a broader pair. From the anterior margin of this area arise two vascular trunks which diverge outwardly and recurve, following the margins of the valve. These give off a series of branches externally and probably a shorter series toward the center of the valve. The ovarian markings are very distinct about the bases of the dental sockets. The external surface of the shell is smooth or covered with very fine con- centric lines. The shell substance is fibrous and apparently impunctate. Whether this species was spiriferous has not been determined, none of the specimens examined hiiving shown evidence of brachial supports. In some respects the charsicters of the species are suggestive of Orthis ; for example, the well developed, bilobed, recurved cardinal process, filling the delthyrium of the brachial valve and extending beyond the plane of the cardinal area ; the vascular sinuses, and to some extent, the arrangement of the muscular impressions. These features, taken in connection with the delthyrium of the pedicle-valve, which does not appear to have been covered, though sometimes partially filled with an apical accretion, may perhaps be interpreted as confirm- atory evidence of the non-spiriferous character of the species. Metaplasia pyxidata was described from the Oriskany fauna of Cumberland, Maryland. It is known to occur also in the Oriskany of New York and Canada, as well as in the decomposed chert of the Corniferous limestone in the Province of Ontario. It may be here observed that the very peculiar species Spirifer cheiroptyx, described by d'Archiac and de Verneuil,* from the middle Devonian at Paffrath, and its ally in the Carboniferous limestones of Vise, S. Oceani, d'Orbigny,f have * On the Fowils of the Older Deposits of the Rhenish Provinces: Trans. Qeol. Soc. London, vol. vi, p. 370, pi. XXXV, figs. 6, a, b, 1842. t Pi-odrome de Paltontologie stratigraphique, pi. i, p. 149, 1850. See, also, Db Koninck, Faune du Cal- ciUre carbonifSre de la Belgique, 8e partie; Brachiopodes, p. 132, pi. xxviii, figs. 11-16, 1887. 58 PALEONTOLOGY OF NEW YORK. a deep sinus on the brachial valve, and also a corresponding sinus on the opposite valve. Kach valve is divided externally by two strong divergent ridges, into three depressed areas, one central and two lateral. Quenstedt, considering both species identical, erected for their reception* a special sub- division of his Aperturati, viz., Cincta. The hinge is long and the cardinal areas on both valves well developed ; the surface is smooth or covered with fine con- centric lines. Little is known of the interior, but it appears from Quenstedt's description that a cardinal process is well developed and that the shell con- tains spirals similar to those of Spirifer. It is very evident that, in association with this most peculiar exterior which of itself necessitates a separation of these species from Spirifer, will be found other peculiarities not pertaining to any of the subdivisions of that genus here adopted. To render the classification of the spiriferoids more homogeneous we propose for this aberrant group the designation Verneuilia (see plate xxxix). Genus WHITFIELDELLA, nom. nov. PLATE XLVIU. 1828. Terebraluia, Dalman. Kong. Vetenskaps-Akad. Handlingar, pi. vi, fig. 7. 1842. Atrypa, Vakoxkm. Geology of N. Y. ; Kept. Third Dist., p. 112, fig. 5. 1843. Atrypa, Hall. Geology of N. Y. ; Rapt. Fourth Dist., p. 71, fig. 3; p. 142, fig. 5 j Tables of Organic RemainB, No. 13, fig. 5. 1852. Atrypa, Hall. Paleontology of N. Y., vol. ii, pp. 9, 76, 77, 260, 268, 269, 328, pi. iv, figs. 4, 5 ; pi. xxiv, figs. 1-4, 6 ; pi. Iv, figs. 1, 2, 4 ; pi. Ixxiv, fig. 10. 18R6. Atrypa, BiLLi»as. Canadian Naturalist and Geologist, vol. i, p. 137, pi. ii, fig. 9. 1858. Atrypa, Rogkbs. Geology of Pennsylvania, vol. ii, part ii, p. 823, fig.'634. 1869. Merista, Hall. Pulteontology of N. Y., vol. iii, p. 253. 1869. Merista, Hall. Twelfth Rept. N. Y. State Cab. Nat. Hist., pp. 77, 78. 1862. Athyris, Charkmdlaf, Billings. Palseozoic Fossils, vol. i, p. 146, fig. 124 j p. 166, fig. 150. 1863. AthyrU, BtLusae. Geology of Canada, p. 317, figs. 320, 332-334. 1863. Meristella, Hall. Transactions of the Albany Institute, vol. iv, p. 226. 1867. MerUtina, Hall. Paleontology of N. Y., vol. iv, p. 299. 1867. MerUtella, Davidson. British Silurian Bracbiopoda, p. 112, pi. xxi, figs. 1-10. 1868. Athyrist, McCnsgNBT. Ti-ans. Chicago Acad. Science, vol. i, p. 33, pi. viii, fig. 2. 1873. MerUtetla {f Merittina), Mbbk. Paleontology of Ohio, vol. i, p. 180, pi. xv, fig. 2. 1873. Athyris, Nichouson and Hindb. Canadian Journal, vol. xlv, new ser., pp. 144, 157. 1875. Athyris, Nicholson. Palaeontology of the Province of Ontario, p. 61, fig. 32o ; p. 62, fig. 32e. 1879. Meristina, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p. 160, pi. xxv, figs. 1-7. 1882. Meristina, Davidson. British Silurian Brachiopoda, Supplement, p. 94, pi. iv, figs. 20-23. 1882. Meristina, Hail. Eleventh Rept. State Geologist of Indiana, pp. 300, 301 ; pi. xxv, figs. 1-7. * Petrefact«nkunde Deutschlands; Brachiopoden, p. 610, pi. liii, figs. 70-72. 1871. BRACHIOPODA. 59 1882. Meristella, Whitfield. Geology of Wisconsin, vol. iv, p. 321, pi. xxv, fig. 5. 1883. Meristella, Hall. Transactions of the Albany Institute, vol. x, p. 71. 1889. Meristina, Nettblboth. Kentucky Fossil Shells, p. 102, pi. xxxiii, figs. 10, II. 1889. Meristina, Bebchbr and Clarke. Memoirs N. V. State Mus., pp. 67-70, pi. vii, figs. 4-13. Diagnosis. Shells usually of small size ; valves subequally convex, ovate or elongate in outline. Umbo of the pedicle-valve not high or greatly incurved, usually exposing the circular apical foramen, beneath which the deltidial plates are frequently retained. Cardinal slopes of both valves broad and not distinctly defined ; anterior margin subtruncate and gently sinuate. In the typical forms there is a faint sinus on both valves near the anterior margin, otherwise the surface is smooth. On the interior the muscular impressions of the pedicle- valve are similar to those of Meristella. In the brachial valve the hinge- plate is concave, divided by a deep central concavity which is supported by a median septum. On either side are the lobes bearing the bases of the crura. The brachidium* consists of two spiral cones arranged as in Merista, but as a rule the ribbon makes fewer (from six to twelve) volutions at maturity. FlO. 48. Flo. 44. The loop or WhUfMdella nUida, Ball, (c.) The loop is simple, the branches being more nearly erect than in Merista, Meristella, etc., and beyond their junction continued into a short, acute, gener- ally slightly curved process, which makes a large angle with the direction of the lateral branches. The muscular impressions, which are very faint, are divided, longitudinally, by the median septum, and, transversely, into anterior and pos- terior .scars. From the ante-lateral margins of the muscular area in both valves, radiates a series of vascular sinuses, the principal trunks of which are very con- spicuous ; this feature, however, is rarely retained. External surface of the valves smooth or concentrically striate. Shell-substance fibrous, impunctate. Type, Atrypa nitida. Hall. Niagara group. • The term brachidium may be applied to the calcified brachial supports of all Brachiopoda. 60 PALEONTOLOGY OF NEW YORK. Obsbrvations. This name is proposed as a substitute for the term Mertstina in its current application to species not congeneric with M. Maria. The num- ber of these species is, probably, comparatively large, and their features subject to considerable variation, though, with few exceptions, there are none having the structure of the brachidium as described above, which present difiFer- ences in other respects sufficient to justify a separation from the type form. Heretofore the structure of the loop in this group has not been correctly dem- onstrated. Mr. Davidson figured and described preparations of Atrypa nitida and Terebratula didyma, Dalman* (which he regarded as equivalent terms), showing a loop erect and slightly inclined backward at its tip, but without the simple posterior prolongation ; he applies to these species the generic term Meristina. The reasons are given elsewhere for restricting the genus Meristina to species similar to M. Maria, Hall ; and though the second species mentioned in the original description of that genus, Atrypa nitida, agrees rather more closely in the form of the loop with the figure given at that time, both species vary from the structure as there represented, which is a condition not yet known to occur among the brachiopods. It is not unlikely, how- ever, that this phase of development may be found among some early athyroid species. We may with reasonable security refer to this genus the following American species : Atrypa cylindrica, Hall, A. intermedia, Hall, A. naviformis. Hall, of the Clinton group; A. nitida, Hall,f A. crassirostra, Hall ( = A. cylindrica. Hall), of the Niagara group, and Charionella? Hyale, Billings, of the Guelph limestone. With these are probably to be associated Atrypa oblata, Hall, of the Medina sandstone, and Athyris Harpalyce, Billings, of the Lower-upper Helderberg * Silarian Brachiopoda, Supplement, pi. iv, figs. 20-23a. t In the original description of this species the appellation nitida was applied to a small form, elongate- snlitriangalar in outline and subtruncate on the anterior margin. At the same time a largei- form with a more gradual anterior slope was designated as var. oblata. It is the latter which agiees more closely with the very abundant shell in the Niagara fauna of Waldron, Indiana, subsequently identified aa Meristdla nitida (Twenty-eighth Annual Report of the New York State Museum, p. 160. 1879), while the typical form of the siiecies is found in the extension of the Niagara fauna to the southward, in the vicinity of LnaisvlUe, Kentucky. The similarity of the Waldron variation to the Meristina didyma, as identified by Datidtok from the English Silurian, is very close, while the typical Atrypa nitida seems to maintain per- manent differences. The Qotlaod foi-ms of Atrypa didyma have a higher umbo than any of the American shells, constantly exiMsing Ihe deltidial plates and the entii-e length of the pedicle-opening. BRACHIOPODA. 61 fauna of Square Lake, Maine. Of the foregoing species we know the character of the loop in Whitfieldella cylindrica, W. nitida and W. intermedia. The forms of Whitfieldella cylindrica occurring in the Niagara limestone at Hillsboro, Ohio, have a remarkably elongate shape, broad and abrupt cardinal slopes on the pedicle-valve, subnasute anterior extremity. In these respects the species differs from other members of the group, but the character of its loop as developed from a solid internal cast in silica, requires, for the present, its retention in this association. A very similar species in all external characters is Dalman's Atrypa prunum, from an equivalent horizon in Gotland Genus HYATTELLA, gen. nov. PLATE XLVUI. This terra is introduced for a group represented by the peculiar species, Atrypa congesta, Conrad, of the fauna of the Clinton group. This species has been found to possess a loop like that of Whitfieldella, but presents some significant points of variation from that genus in other re- spects, viz. : „ . - Fig. 45. The loop of Byaitella Ihe form is compactly subpentahedral ; the umbo congesta, hm. (o of the pedicle-valve acute, concealing most of the deltidium. The pedicle- valve bears a strong median sinus and two faint lateral sinuses, the opposite valve having corresponding folds. The surface of the shell and the ante-lateral margins are strikingly sinuate. Fine, sharp, closely crowded concentric striae cover the exterior. The interior of the pedicle-valve has a deep and strongly striate pedicle-cavity, bounded by strong dental lamellas ; the diductor scars are distinctly defined, enclosing a linear adductor. In the brachial valve the hinge-plate is triangular and divided medially by a deep cleft. The lateral portions are broad and elevdted, supporting short, straight crura. The spiral ribbon makes not more than six volutions, forming very loose coils. There is no median septum. 62 PALEONTOLOGY OF NEW YORK. The differences from other ineristelloids are sufficient to justify the separa- tion of this species, witli which we are at present able to associate only the form described by Mr. Billings as Athyris Junta, from the Anticosti group, Divisions 2-4* Gends DAYIA, Davidson. 1881. PLATE LV. 1839. Tgnbratula, i. db C. Sowbbby. Murchison's Silurian System, pi. v, fig-. 7. 1848. Atrypa, McCoy. Synopsis Silurian Fossils of Ireland, p. 40. 1847. Ter^ralula, Barbandk. Silur. Brachiopoden aus BOhmen, pi. xv, tig. 4. 1848. Tertbratula, Davidson. Bull. Soc. Geol. de France, sec. ser., vol. v, pi. 328. 184S. HypothyrU, Phillips. Mem. Qeol. Survey Great Britain, p. 281. 1852. HemithyrU, HcCot. British Palaeozoic Fossils, p. 204. 1859. Rhyndumella, Saltkr. Murchison's Siluria, second ed., p. 545, pi. xxii, fig. 12, 1860. Rhynchonella, Lindstb5m. Gotlands Brachiopoder, p. 381. 1869. Rhynclumellaf, Davidson. British Silurian Bi-achiopoda, p. 190, pi. xxii, tigs. 20-23. 1881. Dayla, Davidson. Geological Magazine, new ser., vol. viii, p. 291. 1882. Dayia, Davidson. British Silurian Bracbiopoda, Su})plement, p. 96, pi. v, figs. 1-4. Mr. Davidson has established this genus upon the little species, Terebratula navicula, J. de C. Sowerby, from the Wenlock and Ludlow formations of Great Britain and the Island of Gotland. In his earliest description he referred the species with doubt to Rhynchonella,! and at that time gave an elaborately illustrated account of the peculiar interior surface characters of the valves. Subsequently, J ascertaining from the preparations of the brachidium made by the Rev. Mr. Glass, the distinctive structure of the loop, he proposed it as the type of a new generic division. The shells of this species are small, subtrihedral in contour, with a very convex pedicle-valve which may be obscurely keeled along the middle and de- pressed laterally ; and a brachial valve which is convex posteriorly, but becomes concave over the anterior region, and bears a well developed median sinus. The hinge-line is short ; the cardinal area absent. The umbo of the pedicle-valve is gibbous and its apex closely incurved, concealing the foramen. Deltidial plates were probably developed but they appear to be invariably lost in separated valves. The delthyrium is wide, the teeth divergent, moderately conspicuous and unsupported by lamellae. In the bottom of the valve are two * Oataloguea Silurian Kosidla of Aulicusti, p. 46. 1866. t Britisb SiluHan Bracbinpooth of this siiecies and of M. passer, Barrande (Systfime Silurien, vol. v, pis. s, ziii, dr), and in A.merican species of this genus. BRACHIOPODA. 71 their apices directed toward the lateral margins. The loop has been shown by the Rev. Norman Glass to have the following structure : the lateral branches approach and unite near the middle of the interior cavity, forming a very short stem, from the posterior extremity of which is given off a pair of arms. These curve down- ward to the primary lamellae of the coil and returning, meet the lateral branches below their point of union ; the whole forming a scissors-shaped arrangement essentially like that of Meristella, differing only in minor respects indicated under the discussion of that genus. External surface of the valves smooth or with concentric growth-lines. Shell-substance fibrous. Type, Terebratula herculea, Barrande. Etage E. Fig. M. The spirala and loop of iferiata herculea, Barrande. (After Davidson, from a prepara- tion by Glass.) Observations. Merista is a genus rather sparingly represented in species, though some of the species, like M. scalprum, Roemer ( = M. pkbeia, Sowerby), of the European middle Devonian, are very abundant in individuals. In American faunas there are but three forms which may at present be refer- red to the genus, M. typa, Hall, M. elongata, Hall, a probable variety of the former, from the Lower Helderberg fauna at Cumberland, Maryland, and a new species, M. Tmnesseensis, from a similar horizon in Perry county, Tennessee. It appears from the description of the genus above given, that the essential difference between Merista and Meristella lies in the existence, in the former, of the plate termed by Kino the " shoe-lifter process " ; the variations in the structure of the loop and hinge-plate being of minor importance. This internal plate, free at its inner edge, must have induced some important modification in the functions and internal arrangements of the animal. It is evident that its upper surface was one of muscular insertion, and whatever may have been 72 PALEONTOLOGY OF NEW YORK. the causes producing it, the cavity beneath it unquestionably enclosed and pro- tected delicate portions of the viscera* The term Camabium, Hall, was proposed for Merista typa {=Camarium typum). Hall, before the structure of M. herculea, Barrande, was well understood ; sub- sequently the name was withdrawn. Camarium typum is, however, a shell with some interesting peculiarities and susceptible of great variation in the form and size of its " shoe-lifter." This is sometimes very narrow, as in the other species of the genus, but is oftener very wide on the margin and may extend for fully two-thirds the diameter of the valve. Usually it is evenly and highly arched, but often is sharply angled and abruptly elevated. The dental lamellae may extend for a short distance over the surface of the plate, ending abruptly, or they may be produced along its margins as two greatly thickened, callous ridges. In these features, however, there does not appear to be any good basis for a separation of this species from its allies. The genus Merista has usually been regarded as ranging from the faunas of the upper Silurian (Wenlock, Etage E, etc.) into the middle Devonian. In European faunas it appeared before the age of the genus Mekistella, but in America the appearance of the two genera was contemporaneous. It would be altogether natural to presume that species occurring so late as the middle Devonian and after so great an interval from the disappearance of the typical forms of the genus, must have undergone some more or less substantial modification. This is the case with the Devonian Merista scalprum, F. Roemer ( = A/, plebeia, Sowerby), from the Eifel and Devonshire. A careful examina- tion of a considerable number of individuals from Pelm shows that a " shoe- lifter " is quite as conspicuously developed in the brachial as in the pedicle- valve, while the cavity beneath it is divided into two compartments by the median septum which extends beyond the anterior edge of the platform thus • There can be no doobt that this plate in Merista is quite analog'ous to the supported spondylium of Pb>tambbd8, Cahabophoria, etc., as well as to the platform of the Trimerellids, to which attention has been directed in the pi-ece60. Athyris, Whitk. Journal Boston Soc. Nat. Hist., vol. vii, p. 229. 1860. Athyris, Hall. Thiiteenth Rept. N. Y. State Cab. Nat. Hist., pp. 73, 89, 93, figs. 1-47, p. 94. 1860. Athyris, McChksnby. New Palaeozoic Fossils, pp. 46, 47, 80, 81. 1860. Athyris, Billi.ng.s. Canadian Journal, vol. v, p. 278. 1860. Spirigera, Swallow. Ti-ans. St. Louis Acad. Sci., vol. i, pp. 649-652. 1861. Athyris, Newberry. Ive's Rept. on the Colorado River of the West, p. 126. 1861. Athyris, Saltbr. Quart. Journal Geol. Soc. London, vol. xvii, p. 64, p]. iv, fig. 4. 1861. Athyris, BiLLmns. Canadian Journal, vol. vi, pp. 138, 145, figs. 54-57. 1861. Athyris, McChbsnky. New Palteozoic Fossils, pp, 78, 79, 81. 1861. Athyris, Hall. Fourteenth Rept. N. Y. State Cab. Nat. Hist., p. 99. 1862. Athyris, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., p. 180, figs. 1-4 ; pi. iii, figs. 10-13, 15, 16, 24. 1862. Athyris, Billings. Palseozoic Fossils, vol. i, p. 144. 1863. Athyris, Billings. Geology of Canada, p. 373, fig. 399 ; p. 385, fig. 421. 1863. Spirigera, Swallow. Trans. St. Louis Acad. Sci., vol. ii, pp. 83-91. 1863. Spirigera, A. Winchbll. Proc. Acad. Nat. Sci. Philadelphia, vol. vii, sec. ser., p. 6. 1863. Athyris, Davidson. Quart. Journal Geol. Soc. London, vol. xix, p. 170, pi. ix, figs. 4, 5. 1864. Athyris, Daviuson. Monogr. Brit. Devon. Brach., p. 13-19, pis. iii, iv. t 1865. Athyris, Shalbb. Bull. Mus. Comparative Zoology, No. 4, p. 69. 1865. Spirigera, A. Winchbll. Proc. Acad. Nat. Sci. Philadelphia, vol. ix, pp. 117, 118. 1866. Spirigera, A. Winchbll. Geol. Rept. of the Lower Peninsula of Michigan, p. 94, 84 PALEONTOLOGY OF NEW YORK. 1866. Athsfris, Mrm and Worthk!*. Geol. Survey of Illinois, vol. ii, ji. 254, pi. xviii, fig. 8. 1866. AthyrU, Obihitz. Carbon und Dyas in Nebraska, pp. 40, 42, pi. iii, fi(f8. 7-9. t 1866. Athyrix, BiLLlsas. Catalogue Silurian Fossils of Anticosli, pp. 47, 48. 1867. /4ttyri», Hall. Twentieth Kept. N. Y. SUte Cab. Nat. Hist., pp. 152, 3fi8. 1867. Atkyru, Hall. Paljpontolojry of N. Y., vol. iv, pp. 282-293, pis. xlvi, xlvii, figs. 1-33. 1867. AthyrU, Hall. American Journal Science, vol. xliv, p. 48. 1868. Aihyri* f McChbssby. Trans. Chicago Acad. Science, vol. i, p. 33, pi. vi, fig. 4. 1869. Spir'igera {Athyris), Todla. Sitaungsb. der kais. Akad. der Wissensch., vol. lix, p. 6, pi. i, fig. 5. 1871. AthyrU, Mkbk. Hayden's U. 8. Qeol. Survey of Nebraska, p. 180, pi. i, fig. 12; pi. v, fig. 8 ; pi. viii, fig. 4. 1873. Athyris, Mkkk and Wokthbk. Qeol. Survey of Illinois, vol. v, p. 570, pi. xxv, fig. 14. 1874. AthyrU, Dbrbt. Bulletin Cornell University, vol. i, pp. 7, 10, pi. i, fig. 6, 8j pi. ii, figs. 9-12; pi. iii, figs. 8, 16-21, 29 ; pi. vi, figs. 2, 16 ; pi. ix, figs. 4-6. 1875. AthyrU, Mbkk. Palieonlology of Ohio, vol. ii, p. 283, pi. xiv, fig. 6. 1876. Spiriymi, Whitk. Wheeler's Expl. and Survey West of the 100th Meridian, vol. iv, pp. 91, 92, 141 ; pi. V, figs. 11, 12 ; pi. x, figs. 5, 6. 1876. AthyrU, Mkkk. Bull. U. S. Geol. Survey of the Terr., vol. ii, pi. i, fig. 2. 1876. AthyrU, Dkrbt. Bull. Mus. Comparative Geology, vol. iii, p. 279. 1876. AthyrU, Mkkk. Simpson's Kept. Expl. Great Basin of the Terr, of Utah, p. 350, pi. ii, fig. 4. 1877. AtliyrU, Hall and Wbitfibld. King's U. S. Geol. Expl. 40th Parallel, vol. iv, pp. 256, 257. 271, pi. iv, figs. 10, 11, 15-17 ; pi. v, figs. 19, 20. 1877. AthyrU. Mbbk. King's U. S. Geol. Expl. 40th Parallel, vol. iv, pp. 81-83, pi. viii, fig. 6 ; pi. ix, figs. 3, 4. 1878. AthyrU, Dawsom. Acadian Geology, thii'd ed., p. 290, fig. 88. 1880. Athyris, Whitb. Second Ann. Rept. Indiana Bureau of Statistics and Geology, p. 502, pi. iv, figs. 8, 9. 1881. Athyris, Wuitk. Tenth Rept. State Geologist Indiana, p. 134, pi. iv, figs. 8, 9. 1882. Athyris, Whitfiblp. Bulletin American Museum of Natural Histoi-y, vol. i, pp. 49, 50, \t\. vi, figs. 18-27. 1883. AthyrU, Hall. Twelfth Report of the State Geologist of Indiana, pp. 328, 329, pi. xxix, figs. 18-27. 1884. AthyrU, Whitb. Thirteenth Rept State Geologist Indiana, p. 136, pi. xxxv, figs. 6-9. 1884. AthyrU, Walcott. Monogi-. U. S. Geol. Survey, vol. viii, pp. 148, 222, pi. xviii, fig. 6. 1884. AthyrU, Wortkbn. Bull. Illinois State Mus. Nat. Hist., p. 24. 1887. AthyrU, Hbrrick. Bull. Denison Univereity, vol. ii, p. 44, pi. ii, fig. 23. 1888. AthyrU, Kbyks. Proc. Acad. Nat. Sci. Philadelphia, p. 10. 1888. AthyrU, Hbrrick. Bull. Denison Univereity, vol. iii, p. 49, pi. ii, figs. 1,7; vol. iv, pp. 14, 24, pi. iii, fig. 6. 1889. AthyrU Nbttblroth. Kentucky Fossil Shells, p. 87, pi. xvi, figs. 25-32. 1890. AthyrU, Worthkji. Geol. Survey of Illinois, vol. viii, p. 103, pi. xi, fig. 2. " General Characteristics. — Nearly orbicular, small ; no cardinal area or hinge- line; spiral appendages very large, filling the greater part of the shell." — McCoy, op. cit., p. 146. Diagnosis. Shells subequally biconvex ; outline transversely elliptical, sub- circular or elongate-subovate ; surface medially sinuate. BRACHIOPODA. 85 In the pedicle-valve the beak is inconspicuous and incurved, usually con- cealing the foramen and deltidial plates ; frequently, however, the former is exposed. Cardinal slopes not well defined in the typical group. The convexity of the valve is greatest in the umbonal region, the surface sloping evenly to the sides, and becoming depressed on the median line into a sinus, which is most conspicuous on the anterior margin. Beak of the brachial valve not promi- nent ; a median fold corresponds in strength to the sinus of the opposite valve. In the interior of the pedicle-valve the deltidial plates are usually absent ; the teeth are prominent, recurved at the tips, and supported by stout dental lamellae, which are not produced anteriorly about the muscular area. Between them lies a deep, transversely striated pedicle-cavity, and in front of this an ovate muscular scar extending about one-half the length of the valve and divided into flabellate diductors (which are frequently very indistinct) and nar- row, cordate adductors. The pallial region is covered with ovarian pittings and branching sinuses. In the brachial valve the dental sockets are broad and deep. The hinge- plate varies considerably in form ; in the typical division of the genus it is subtriangular in outline, and supported by stout crural plates. The median portion is flat or concave, the lateral margins thickened and elevated. At the apex of the plate and just within the beak of the valve is a circular perforation (viscercal foriimen), which is continued beneath the plate into the cavity of the valve. The anterior margin of the plate is straight or slightly concave, occa- sionally trilobate, and the crura are attached at the extremities of the lateral ridges. Sometimes the outliiie of the hinge-plate is rendered subquadrate by the development of two post-lateral expansions. The brachidium consists of spiral cones lying base to base, with their apices directed laterally. The form of these cones varies with that of the internal cavity, but as a rule they are much compressed vertically, the posterior curva- ture being short and convex, while the anterior curve is long and sometimes depressed. The crura originate from the hinge -plate at a large angle, are long and convergent ; the primary lamellae arising from their extremities, make an angular curve at their origin, thence, in the typical species, curving deeply 86 PALEONTOLOGY OF NEW YORK. upward and backward, to form the first volution. The spirals are connected by a loop, which takes its origin on the first half of the primary lamellae, the ^-- — • - ^^'^"'^ ^^.^ —^ ^ >^o^ 1 — r • ••- I. / a c — ' ^ < FlO. 87. Diagram of the straotnre of tho bracbidinm In Atuyeis. z. Spiral coil. I. Saddle. a. Primary lamella of spiral ooU. m. Fimbriated extensions of saddle. a'. Secondary lamella. (. Stem of loop. a". Umbonal blades. A Arms of loop, c Cmra. b. Accessory lamella. (. Loop. n. Fimbria on oater margins of lamella, c. Lateral branches of loop. two lateral lamellae converging, and uniting at about half the distance across the base of the cones, to form a broad saddle with a convex upper surface ; the anterior extremity of this saddle may be simple or divided ; its posterior por- tion is narrowed, inclined downward or toward the beak of the brachial valve for a short distance, thence it rises abruptly toward the umbo of the pedicle- valve, and bifurcates near the extremities of the crura, each branch following the curvature of the primary lamellae and continuing for only a part of the dis- tance between the ends of the crura and the origin of the loop. These acces- sory lamellae vary somewhat in form, are narrower than the ribbon of the coil, and lie between the primary, and the first band of the secondary lamellae. ''., ^^ ,> 'h "% V V^ 0 ,0'^ FlO. 68. FIO. 09. Pig. M. Vertical section of AlhyrU $ubtUUa, Hall, Jast back of the loop ; showing the crura («) and the acoe'sory lamella (a). Fl*. ». VertJeal section of Athyri* tubtUUa, Hall, through tho stem of the loop. This view shows the great width of the primary lamella, the Inclination of the accessory lamella (o, a) to them, and the thickened inner •dfe* of the keoondary lamella. (o.) BRACHIOPODA. 87 The muscular area consists of a long, ovate scar, which is divided into a subquadrate posterior pair, and a subcordate anterior pair of adductor impres- sions. These are separated longitudinally by a very faint median ridge. On casts of the interior the filling of the visceral foramen in the hinge-plate fre- quently shows a cross-striation like that of the pedicle-cavity of the opposite valve, and also indicates that the median ridge is continued throughout the extent of this passage. The surface of the valves is variously ornamented ; in the typical group, at each concentric growth-line, there is a broad lamellar expansion ; in some cases this expansion is striated longitudinally, or it may be divided into flat spines, which merge into the lamella at their bases; again the spines may be long and tubular, but connected by the laminar expansions. The surface frequently appears to be smooth, or covered only with concentric striae, and in one of the largest subdivisions of the genus (Seminula) this is a normal condition, while in other divisions it is often altogether casual. Shell-substance fibrous, impunctate. Type, Terebratula concentrica, von Buch. Middle Devonian. Observations. The number of species which, in common usage, are referred to Athtris, is very great. This name, like those of some other genera, Orthis, Strophomena, Atrypa, etc., has been a convenient receptacle for forms whose intimate relations were not thoroughly known; but the investigations of King, Davidson, Glass, Zugmayer, Bittner, and other careful students of the spiriferous brachiopods, have done much to eliminate from this association some of the more positively heterogeneous material. The diagnosis above given is restricted pretty closely to the essential characters of the well known species, Terebratula concentrica, von Buch, which, in the absence of any specified type, is usually, and quite properly regarded as the typical species, being it is the first in the list of descriptions accompanying the original account of the genus. McCoy applied the term Athtris to shells, which in his belief, possessed no apical foramen or deltidium, but more careful observation soon showed that the concealment of the cardinal area was but a condition of 88 PALjEONTOLOGY OF NEW YORK. growth, developed earlier in some species than in others, and hence the term wa« essentially a misnomer. On this account some authors, particularly the French and German writers, have preferred to use the term Spirioera, pro- posed by d'Orbigny in 1847* to replace Athyris, and founded on the same species. The term Eothvris, also, was proposed by the late Professor Qoen- 8TBDT,t but it has not come into general use. Among generic appellations there are too many misnomers which have an established and positive value, to permit the rejection of the term Athyris without great inconvenience, attended by no equivalent advantage. The term is therefore used in a re- stricted application and substantial reasons will be given for a subdivision of the genus.J The essential feature which forms the basis of union of all the variations of the genus here discussed, is the nature of the loop. This complicated struc- ture was first demonstrated by Davidson in 1857 § for the species Athyris pectimfera, Sowerby. Since that date our knowledge of this organ has become more extended and more exact, and we now know its peculiarities in several species from the Devonian, Carboniferous and Permian faunas. Athyris concentrica, representing a combination of characters which expresses the typical phase of athyroid structure, is distinguished from the subordinate divisions of the genus by the following differences : (a) The usually transverse form ; this is a feature subject to variation, but throughout the group this outline is striking, simply from the frequency of its occurrence. (6) The lamellar expansions or varices at the concentric growth-lines are simple, that is, are not split up into spinules, nor do they embrace such spinules, but are usually transversely striated. They are often highly developed toward the margins of the valves, but are generally ♦ Comptes rendns, vol. rxv, p. 268. t Petrefaclenkunde Dentschlands, p. 442. 1871. J Students who may wish to follow the variation of opinion in regard to the value of the genus Athyris, •re referreil to a paper by the late Mr. Billtvos, Palffontolo^fist of the Geolotrical Sui-vey of Canada, "On the Claaeification of the Subdivisions of McCoy's Genus Athyris, as determined by the Laws of Zoological Nomenclature;" American Journal of Science, vol. xliv (1867), p. 48. See, also, vol. xxxiii of the same Journal, pp. 127, et neq. f British Permian Brachiopoda, p. 21. BRACHIOPODA. 89 absent, probably from abrasion, on the earlier portions of the shell, and, as already observed, are frequently entirely lost, (r) The hinge-plate is triangular, flat rather than concave in the middle, and without post-lateral expansions; it is, moreover, not elevated above the plane of the margins of the valve. (d) The union of the primary lamellae with the crura is more or less obtuse, the former making a curve upward, away from the crura, passing them again near the hinge-plate ; thus appearing to make a noose on each side at their origin.* (e) The loop is very long, its origin from the primary lamellaa being at or in front of the middle of their length. FlO. 60. riG. 61. The crura and loop of Athyrit tpiriferoides, Eaton. (0.) (/) The saddle of the loop is broad and undivided at its anterior extremity, (g) The arms, or accessory lamellae of the loop, are narrow. (h) The saddle, accessory lamellae and spiral bands are without spinules or fimbria. FIO. 62. The emra and loop or Athyrit vUtata, Hall. FlO. 63. (o.) Of American species which are referable to this typical division of Athyris, may be cited : A. spirifer aides, Eaton, of the Corniferous limestone and Hamilton ♦This peculiar structure was first shown by Mr. R. P. Whitfield, for the species of A. vittata. Hall, mad A. tpiriferoides, Baton, in Volume IV of the Palaeontologry of New York. 90 PALEONTOLOGY OF NEW YORK. group ; A. Cora, Hall, of the Hamilton group ; A. vi'tata* Hall, of the Cornifer- OU8 limestone and Hamilton group; A. Angelica, Hall, of the Chemung group; A. lamellosa, Li'-veilU', of the Waverly and Keokuk groups ; A. incrassata. Hall, of the Burlington limestone, and A. Hannibalmsis, Swallow, of the Choteau limestone. Subgenus CLIOTHYRIS, King. 1850. This name was introduced by Professor Phill[P8, in 1841,f as a substitute for Dalman's term Atrypa, which this author did not regard as appropriate. The term wa.s not subsequently used by him, nor was any typical species mentioned, so that in its original application the term has no meaning. Subsequently, and perhaps unfortunately, Professor William King revived the name, J giving a careful diagnosis and specifying as his type of the genus, Atrypa pecUnifera, J. de C. Sowerby. His description was : " Generally lenticular in form ; minutely punctured ; with variously characterised projecting laminae of growth ; Spirab pectinated ; Dental plates large and separated ; Crural base perforated ; Foramen situated at the point of the umbone, and open inferiorly by the fissure." At this date the genus Athyris was not closely restricted or well understood. Kino followed McCoy in regarding Terebratula concentrica, von Buch, as its type, and demonstrated, though imperfectly, the existence of a process connecting the spiral coils of the shell. Atri/pa pedinifera is a Permian species which varies from the structure in the typical division of Athyris in the following respects : The surface ornamenta- tion consists of broad, thin, lamellar expansions which are divided almost, and sometimes quite to their bases, into long, flat spinules; hinge-plate nar- row and rather acutely triangular ; the primary lamellae are attached to the * These three species are pretty constant in their differences, the first being transverse, squamous forms, the others more orbicular and retaining but traces of the laminae. The species present vaiiations which are included by European palffiontologiats within the limits of Athyris conctntrica, von Buch. t Palteozoic Foiwils of Cornwall, Devon and West Somerset, p. 65. X The Permian Foeails of England, p. 137. BRACHIOPODA. 91 crura not only at their apices but for a short dis- tance along their inner faces, not making the nooses peculiar to Athyris proper ; they are broad and blade-like, narrowing beyond the insertion of the loop ; the loop is situated posteriorly ; the accessory lamellae are narrow near their origin, broaden and then taper again, having the shape of a sickle. The spiral ribbon, from the figures given by Davidson and King, appears to be pectinated on all its outer edges, but it has not been shown that the anterior extremity of the loop is similarly ornamented. FlO. 64. The fimbriated spirals ot Athyris pectin- if era, Sowerby. (Davidson.) These features are of sufficient significance to distinguish this group of species from the typical division of the genus. It must be granted, that as the really essential difiierences are in the structure of the spirals and loop, it will be impossible to make a final arrangement of these species until their internal structure has been fully elucidated. Temporarily, however, the char- acter of the external ornament may be relied upon, inasmuch as we know the internal arrangements with which it is associated in the type-species, Cliothyris pedinifera. This subgenus is equivalent to Waagen's section Ornate, typified by the Athyris Roysii, Leveille,* under which he includes, besides A. Roysii and A. pedinifera, five new species {A. subexpansa, A. capillata, A. semiconcava, A. acuto- marginalis, A. glohulina), all from the upper and lower divisions of the Productus limestone of the Salt-Range of India. In American faunas Cliothyris is rep- resented by the species usually identified as A. Roysii, in the Waverly and Keokuk divisions of the lower Carboniferous, A. hirsuta, Hall (= A. americana. Swallow), from the St. Louis and Chester limestones, and A. sublamellosa. Hall, from the Burlington limestone. • Prodactus limestone Fossils, p. 478. 1883. 92 PALEONTOLOGY OF NEW YORK. SoBOENCs ACTINOCONCHUS, McCoy. 1844. In the same work that contained the original description of Athyris, McCoy proposed the above term for a shell which he described as Actinoconchus paradoxus. •• General Characteristics. — Shell globose ; the margin of both valves greatly extended, forming a flat, circular, striated disc ; spiral appendages as in Athy- ris."—{Op. cit., p. 149.) Its affinities with Athyris were evident to the author, and later writers have regarded it simply as a synonym for that term. The Actinoconchus paradoxus was subsequently shown by Davidson to be the same shell as Phillips' Spin/era (= Athyris) planosulcata (1836), which McCoy had himself identified among the Carboniferous fossils of Ireland from desquamated specimens (p. 148).* There seem to be excellent reasons for reinstating this term in its original application, as Athyris planosulcata is a strongly individualized species which may well serve as the type of a group. It is characterized by the extravagant development of the concentric lamel- lar expansions! which are striated radially by distant sulci " about half a line apart" (Davidson). These expansions appear to be actually fine, tubular spines connected by, or imbedded in a tenuous calcareous plate. The interior of the pedicle-valve bears a median septum which traverses the pedicle-cavity and half the length of the shell ; also two strong dental plates which are continued forward, slightly diverging, fpr more than one-half the length of the septum. Mr. Davidson has given elaborate illustrations of the spirals and loop of this species, from preparations by the Rev. Norman Glass,| and from them it appears that the latter organ, the loop, has essentially the same conformation as in Cliothyris pectinifera, though it is placed further forward (see Silurian Supple- ment, p. 98, fig. 1.). The saddle of the loop is neither divided nor pectinated, while the spiral ribbon bears short spinules " on the edge and face of the lamellse fronting the sides of the shell " (Davidson). Athyris planosulcata is a species * McCoT afterwards refeireil the species to the genus Athyris : British Palaeozoic Fossils, p. 486. 1865. t See Datidsoh's superb fif^res in Carboniferous Brachiopoda, pi. xvi., figs. 7, 8. t Supplement to British Silurian Brachiopoda, p. 98, figs. 1, 2, pi. iv, figs. 14-19. BRACHIOPODA. 93 which has a wide distribution through the lower and upper Carboniferous of England, Ireland and Belgium. Subgenus SEM INULA, McCoy. 1844. This is another term proposed in the " Synopsis of the Carboniferous Fossils of Ireland," which has been absorbed into the genus Athyris by later writers. On page 150 of his work, McCoy mentions Seminula as " a genus formed for the reception of those little species which have a minute perforation but want the deltidium," and further, on page 158, describes the genus as follows: " General Characteristics. — Shell small, subpentagonal ; smooth or slightly plaited at the margin ; beak of the dorsal valve small, with a minute perfora- tion; no deltidium. " The species of this genus are all small ; the margin frequently indented, but no distinct plait.s on the surface ; the outline is usually more or less pent- agonal ; the beak has a very minute foramen for the passage of the muscle of attachment, but there is no deltidium separating the foramen from the hinge. " The genus is peculiar to the Palaeozoic rocks." In this place the author described three species, the first of which, Seminula pentahedra, Phillips (sp.), may be taken as the type in absence of any specified typical species. Phillips' species has been shown to be synonymous with Spir- ifer ambiguus, Sowerby, and is antedated by it. The other forms referred, in the work cited and subsequently, to Seminula by McCoy, have been shown by Davidson to be not congeneric with S. (^Athyris) ambigua. No generic import- ance can now be given to the apparent absence of the deltidium in this shell ; it is simply concealed as in many other Athyres by the incurvature of the beak. Mr. Davidson has described and elaborately figured the Athyris am- bigua* and from his work, with the aid of a series of specimens from the Car- boniferous limestone of Great Britain,! it appears that the shell has certain characters which do not permit its easy association with the other subdivisions of Athyris. The smooth exterior of the species, its subpentahedral form and • Carboniferous Brachiopoda, p. 77, pi. xv, figs. 16-22 ; pi. xvii, figs. 11-14. 1858. t For some of which we have been indebted to Prof. John Young, of the Hunterian Museum, Glasgow. 94 PALEONTOLOGY OF NEW YORK. sinuate valves are distinctive features and to these must be added the peculiar character of the muscular scars. This subtype is largely represented in the American Carboniferous faunas and from an examination of its various species we deduce the following characterization : Shells transverse, often elongate or ficiform ; valves biconvex, the pedicle- valve with a median sinus over the pallial region, and the brachial valve with a corresponding ridge ; both sinus and fold may be divided by a sharp median sulcus extending from the umbones to the margins. There is frequently evi- dence of a single obscure lateral fold on each side of both valves. The umbo of the pedicle-valve is incurved and the deltidial area is usually concealed ; the foramen, however, is exposed as a circular or ovate aperture which encroaches on the substance of the valve. In the pedicle-valve the diductor muscular im- pressions are very faintly defined ; the adductor and pedicle impressions are as in the typical forms of Athyris. In the brachial valve the hinge-plate is highly developed, its upper face being subquadrate in outline, concave on the surface, the concavity deepening toward the visceral foramen which lies just beneath the beak ; not infrequently the foramen is closed by secretions of testaceous matter. The posterior flanges of the plate pass beyond the hinge-line and into the umbonal cavity of the opposite valve. The anterior face of the plate is erect and the anterior edge somewhat trilobed, the lateral lobes bearing the crural bases. The crura are straight and their attachment to the primary lamellse is of the same character as in Cliothyris, etc. The primary lamelljE, on the umbonal curve, are broad, the loop usually situated posteriorly. The saddle of the loop is often bilobed on its anterior margin, and frequently fio. k. , . . Loop of AthyrU Mnuclea, both it and the outer margins of the ribbon of the sec- Haii. .ui. Louis lime- stone, (o.) ondary volutions are fimbriated. The muscular impressions of this valve are very narrow, and subdivided into two pairs of elongate scars. The members of the posterior pair are divided by a median septum or ridge, which begins beneath, though it does not support the hinge-plate. Branching vascular sinuses are sometimes retained over the pallial region of both valves. BRACHIOPODA. 95 Surface of the valves smooth, that is, with sharp, concentric striae which were never produced into lamellae. The shells which constitute this group were apparently confined to the faunas of the Carboniferous age. The number of species in American faunas is not great, but we have now a pretty thorough understanding of four, Athyris sub- quadrata. Hall; A. trinudea. Hall, of the St. Louis limestone; A. Dawsoni, sp. nov.,* of the lower Carboniferous beds of Windsor, Nova Scotia; and A. sub- tilita, Halljf of the upper Carboniferous. In all these species we now know the structure of the loop, and though in each it has a characteristic form, its variations are not of great significance. Fio.iee. Fig. 67. The loop of Stminula tubtilUa, Hall. (o.) In A. subtilita its position is more posterior than in the other species, the umbonal blades of the primary and accessory lamellae are broader, the saddle • Identified by Datidsoh aa A. tubtilita. See Quarterly Journal Geological Society, vol. xix. t Athyris tubtilita is a protean species, some of whose variations in general form are illustrated on the accoin|>anying plates. One feels at first disinclined to include under the same specific designation the broadly Bciform, the nan-ow elongate, the sinuate, non-sinuate, and trilobed shells which are customaiily thus i-eferred ; but very abundant material shows the difficulty of sejjarating them. The typical form of the species is the elongate shell, broad over the pallial region, and the extreme variations from this type of ex- terior may have a more or less important faunal or geological value. For example, the most abundant representative of the species occuiring in the upper Coal Measui'es about Kansas City, is a nari-ow, elongate, slightly sinuate shell, one extreme of variation ; again, we have been supplied by Professor S. Calvin with a series of specimens from Wintei-set, Iowa, some of which are as deeply trilobate on the anterior margins as extreme forms of A. tubquadrata ; in both instances these variations are found to pass into the typical form of the species by insensible gradations, and as far as known there is little variability in the structure of the interior. In the St. Louis limestone at Pella, Iowa, there occui's a form which it is impossible to sejmrate from A. tubtilita ; the occurrence of the species at so low an horizon is exceptional, while throughout the Coal Measures it is wide and characteristic. 96 PALEONTOLOGY OF NEW YORK. deeply bilobed, its anterior margin and the edges of the secondary volutions fimbriate. The precise value of this pectination of the ,--;..;•-., saddle and coils it is difficult to determine ; it appears to be developed differently in different individuals. We are not satisfied as to the existence of this character in A. trinuclea and A. subquadrata, but in A. Dawsoni it is absent. Some individuals give indication of the pectina- tion of the stem and the accessory lamellae of the loop, and it has been shown by Zugmayer that in Athyris (Spirigera) oxycolpus, Emmrich, of the Rhaetic beds, the accessory lamellae are deeply serrated, a feature coexist- ing with a bilobed saddle.* In A. subquadrata the lateral branches of the loop are long and projected for- ward at a sharp angle. In A. trinuclea, the origin of the loop is more anterior, the lateral branches erect and high, the surface of the bilobed saddle being close under the opposite side of the coils. Athyris Dawsoni is a very interesting FIG. 68. Pectinated loop of AthyrU oxycolput, Emmrich. (ZVOMATBB.) FlO. 68. FIO. 70. FIO. 71. The loop of AthyrU [Seminula) Dawtoni, sp. nov.; showing the variation in development of the saddle in different iodiTidoaU. Fig. 70 is a view from the umbonal region of the specimen represented in Fig. 69, indicating the marginal position of the accessory lamellae upon the umbonal blades. (C.) form occurring with most beautiful and exceptional preservation, the brachi- dium being retained with the slightest incrustation of calcareous matter upon it; all the rest of the shell and the filling of its interior cavity being removed. In this species the loop is normally almost without a saddle; at the union of the lateral branches there is a slight forward protuberance on each side, the stem arising therefrom almost without angulation ; the accessory lamellae, as shown in the accompanying figures, lie upon the inner edges of the primary * Zdomatbb, Unt«r8uchung«n ueber rhaetische Bracbiopoden ; Beitra«ge zur Palsontologie CE^sterreicb- Ungams and (ies Orients, pi. iii, figs. 21-23, and p. 353, figs. 1-3. 1882. BRACHIOPODA. 97 lamellae, and not between the primary and secondary lamellae as usual ; further- more, these accessory lamellae are very narrow.* While from our present knowledge the group of Seminula must be regarded as confined to the Carboniferous (and Permian ?) formations, there is a little species in the white sandstone of Pendleton, Indiana, in a fauna having much similar- ity to that of the Schoharie grit of New Yorlc, which has many of the internal shell-characters of A. suhtilita. This species, Aihyris Rogersi,-f sp. nov., occurs in the condition of internal casts which show the form of the shell and the muscular impressions as described for Seminula, the subquadrate and perforate hinge-plate and the faint median septum in the brachial valve. The brachidium has not been developed. No other Devonian species showing similar affinities is known. From our present knowledge, the athyroids, of the American palaeozoic faunas appeared with this form, at the opening of the Devonian age. Mr. Davidson has illustrated the spirals of a Wenlock species, Terebratula laviuscula, Sowerby,! which seemed to show the existence of accessory lamellae. This little shell has recently been closely investigated by the Rev. Norman Glass,§ who finds that the loop forms no saddle, and that the intercalary lamellae are * lu the proffpess of this work «ome shells wei-e received from a collection formerly belonging- to the Rev. H. Hbrzkb, of Berea, Ohio, bearing the label "Athyrii ambigua, Cork, Ireland." The specimens possess a rather more transvei-se form than usual in A. ambigva, and the faint cancellation of the exfoliated surface would indicate that it was originally spinous or lamel- lose. It is evident that the species is not A. ambigua, but its specitic identity is still uncertain. There is, however, no species of Athyris of which the loop is known, where this organ (as shown in the accompany- ing figure) is so short and so closely confined to the umlx>nal region. The lateral branches onginate from the primary lamella with a very slight anterior curve, being almost horizontal for a short distance ; the um- bonal blades of the primary lamelliE are very broad, beginning in an abrupt angle with the ci'ura and hav- ing a slight curvature. The saddle is entire on the anterior margin and not fimbriate. t Named for Dr. Bbsjamin Roqbrs, of Pendleton, in i-ecognition of his interest in the development of the fauna of this locality. t British Silurian Brachiopoda, Supplement, p. 101, pi. iv, figs. 24-26. § Geological Magazine, Dec. Ill, vol. viii, p. 495. 1891 . Fig. 72. Loop ot Athyri>, sp. ?, Carboniferous limestone, Cork (?). (O.) 98 PALEONTOLOGY OF NEW YORK. short compared with those of atypical ArHYRisand make but a short curve within the primary himelhe. A very peculiar feature of this structure is tlie absence of an upright athyroid stem, tlie bifurcation of the intercalary lamellae taking place at the point of union of the lateral supports of the loop, the whole apparatus having thus, the form of an inclined X, with its upper tips curved outward. The demonstration of this structure justifies the conclusion of Mr. Glass that the species is not an Athyris, but another of such incipient stages of athyroid structure as are represented by Meristina, Whitkieldella, etc., though lacking the upright jugal stem which all those possess. Mr. Glass has proposed to place the species under Davidson's genus Bifida, where it might perhaps rest, were we confident of the accuracy of the determination of the loop in B. lepida as given by Mr. Davidson (see discussion of the genus Bifida), but ivs the shell certainly represents a distinct variation of structure from any heretofore observed, it will be far more satisfactory to recognize this fact by giving the species some distinctive term, as Glassina. Subgenus SPIRIGERELLA, Waagen. 1883. 1862. Athyris, Davidso.v. Quarterly Journal Geol. Soc. London, vol. xviii, \i. 28, pi. i, fig. 8. 1863. Athyris, De Kosinck. Foss. Paleoz. tie I'lnde., p. 33, pi. ix, fig. 8. 1867. Athyris, Vbrcherk. Jour. Asiat. Soc. Bengal, vol. xxxvi, pt. ii, p. 210, pi. ii, figs. I, I a. 1874. Athyris, Dkrbt. Bull. Coniell University, vol. i. No. 2, p. 7, pi. i, fig. 7. 1883. Spirigerella, Waaobn. Palsontologia Indica, p. 450. Dr. Waagen has proposed to separate from Athyris a considerable group of species, under the term Spirigerella. Adhering pretty strictly to the broader characters of the type-species, S. Derbyi, Waagen, it would seem that his asso- ciation of species* under this term is to a certain degree heterogeneous ; at all events, the group conforming in exterior characters to Spirigerella Derbyi, has a peculiar expression not shared by such forms as S. grandis, S. media, S. ovoid- alis, and S. fusiformis, Waagen. The distinctive features of Spirigerella are as follows; Exteriorly the shells are elongate, but may be transverse; their contour shows a decided tend- * Ten in number, from the Carboniferous rocks of tbe Salt-Range. BRACHIOPODA. 99 ency to piano-convexity, the pedicle-valve being de- C-^^ pressed by a broad, flat sinus, and the brachial valve \^f^M^~^ ^ considerably elevated; the cardinal slopes are more \^kr^^==^<'^ or less pronounced ; the surface is smooth or with ^^^ sharp, concentric growth-lines, which were not pro- ''°"'' "' ^^'">«""" "''Iwaa'IenT"" duced into lamellae or spines. On the interior the hinge-plate is high, the anterior face being erect, the upper face subquadrate in outline and concave, the posterior ftice extending considerably beyond the hinge; perforated by a visceral foramen. The loop is situated pretty well back and its structure is essentially like that in Athyris planosulcata ; in S. Derbyi, however, the saddle of the loop, which is entire on its anterior margin, bears a median septum on its summit, extending from its anterior edge to the bifurcation of the stem ; a feature not elsewhere observed among the athyroids, except in Kayseria. In several respects these characters do not permit the assimilation of forms following the type of Spirigerella Derbyi, with any of the foregoing subdivisions. This subgenus and Seminula include only species with smooth shells; in Spirigerella the hinge-plate attained a larger size than in any other group, though its structure does not differ from that of Athyris subtilita. It will accomplish an excellent purpose to restrict the term . Spirigerella to forms having the subplano-convex contour, strongly developed cardinal slopes, and the septiferous loop. As far as the first two of these features are concerned, such a restriction would include all the forms embraced by Waagen in the typical division of the genus (S. Derbyi, S. pralonga, S. hybrida, S. minuta, Waagen), and also those referred to the group of S. numismalis {S. numismalis and 8. alata, Waagen) ; while it eliminates the group of S. grandis {S. grandis, S. media, S. ovoidalis, S. fusiformis, Waagen). How far the structure of the loop in the re- stricted group agrees with that of S Derbyi, has yet to be demonstrated ; but .ST. grandis, the only species besides S. Derbyi of which the loop is described, has not this vertical septum on the saddle, nor has it, or the group it represents, the contour of the closer allies of S. Derbyi, but is a more regular, elongate and biconvex shell. It seems probable that this group of Indian species will 100 PALEONTOLOGY OF NEW YORK. more naturally rest in association with Seminula subtilita than with the group of Spirigerella Derbyi. We have no satisfactory evidence of the occurrence of Spirigerella in North American faunas. The type of structure characterizing Athyris is continued beyond the PalaBOzoic, being abundantly represented in the Alpine Trias faunas. These later fossils have been studied by various authors, and most recently de- scribed by BiTTNER,* who has subdivided them into a number of groups all of which he holds subordinate in generic value to Spirigera ( = Athyris). Of these, two principal divisions are made : (I) Forms with simple spirals ; (II) Forms with double spiral bands. Of the former are : 1. The "genuine Spirigeras"; under which are included: a. Smooth forms. h. Species with sloping shoulders', retzioid rather than athyroid in out- line, and bearing on the surface a few sharp plications, which, at the margin, are opposite, not alternate ; Pliciqera. KIO. 74. Fio. 76. FlR. 74. TetractineUa trigoneOa. Scblothoim. Fig. 75. Loop oi' IHoristelld ivdUtincta, lleyrich. Fig. 76. AmfkUomella hemitpharoidica, Klipstein. KIG. 7«. (BITTNBB.) * BrachioiMMlen tier Alpinen Tiias: Ahhandl. der k. k. geoUig. Reichsanst., Bnd. xiv. 1890. BRACHIOPODA. 101 ij. Tetractinella includes forms with four ribs on each valve. 64. Pentactinella includes those with five ribs on each valve. 63. Anomactinella includes those with a number of ribs sharply de- veloped toward the margin. 2. Amphitomella ; smooth shells with a very strong cardinal plate, and a median septum in each valve extending the entire length of the shell and dividing the cavity into two chambers. 3. DiORiSTELLA ; smooth shells having a loop whose lateral branches return upon themselves, somewhat as in Meristella. Genus KAYSERIA, Davidson. 1882. PLATE XLI. 1841. OrthU, Phillips. Paljeozoic Fossils Cornwall, Devon and West Somei-set, p. 65, pi. xxvi, fig. 110. 1842. OrthU, d'Archuc and de Vkbnbdil. Descr. Older Deposits Rhenish Provinces ; Trans. Geol. Society, London, sec. ser., vol. vi, p. 396. 1853. Orthix, Steininger. Qeogn. Beschreibung der Eifel, p. 80, pi. v, fig. 5. 1864. Atrt/pa, Davidson. British Devonian Brachiopoda, p. 5}, pi. x, fig. 1. 1871. i?etrfa, QuBNSTKDT. Petrefactenkunde Deutschlands ; Brachiopoden, pi. li, figs. 21-25. 1871. Relzia, Katsbb. Zeitscb. der deutsch. geolog. Gesellsch., vol. xxiii, p. 161. 1882. Xoyamo, Davidson. Devonian Brachiopoda, Supplement, p.' 21, pi. ii, figs. 11, 12. Orlhis lens, Phillips, the type-species of this genus, is a small middle Devonian shell, with depressed-convex or lenticular valves, radially plicated exterior, and a median plicated sinus on both valves. Its external expression is not unlike that of some of the retziiform species which belong to the genus Rhynchospira, though it possesses an impunctate shell. The complicated internal organiza- tion has been elaborated by the Rev. Norman Glass and described at length by Mr. Davidson. The pedicle-valve bears a low, thickened median ridge, but is otherwise devoid of pronounced peculiarities. In the brachial valve there is a high median septum which arises from beneath the divided hinge-plate and reaches its greatest elevation at a point behind the center of the valve, whence it descends rather abruptly, traversing altogether about two-thirds the length of the valve. The spiral cones form sharp angles with the crura, and are directed laterally ; the loop is very stout, taking its origin at about one-third the length of the 102 PALEONTOLOGY OF NEW YORK. primftry ribl)on; it is directed somewhat posteriorly, its lateral elements unit- ing to form a short saddle which rests upon, and is supported by the most elevated part of the median septum. According to Davidson's preparations the loop is continued into an upright simple stem, from the summit of which diverge the accessory lamellae. At this point our own preparations do not fully corroborate this account, but indicate rather that this upright stem is continued completely across the umbonal cavity and comes into contact with the opposite valve, resting upon the median ridge of that valve, or with its extremity inserted into a groove upon that ridge. We further find that the accessory lamellae originate from a posterior eleva- tion or process arising from the saddle of the loop and are given off at points just in front of the crural angles. The ribbon of the principal spiral cones is comparatively broad, thickened on the inner margins, making six or seven volutions in a full-grown shell. The accessory lamellae are also produced into spirals which though more delicate are composed of as many volutions as the principal spirals. At their outset the branches of the accessory lamellae pass between the first and second volutions of the princi- pal ribbon, and the two are intercoiled in this manner for their entire extent. Kayseria is thus an athyroid with double spirals and the only species known Fig. 77. Approximate determination or the loop in Kayseria lens, Phillips. FlO. 78. FIO. 79. rig. 78. Pexidella Strohmaperi, .Suess. •Fl(t. 70. IHplospirelln Wissmanni, Mtlnster. (BiTTNKH.) BRACHIOPODA. 103 in palaeozoic faunas in which the accessory lamellae attain so high a develop- ment. As already observed, Bittner has detected a number of such double-spired forms in the Alpine Trias, over all of which he extends the generic term Athvris (or Spirigera), though he has introduced for them a number of subordinate names based upon slight differences of structure, as follows : Pexidella ; smooth forms with thickened shells, and loop of inconspicuous size. DiPLOSPiRELLA ; smooth forms without shell-thickening and with prominent loop. EuRACTiNELLA ; cinctured forms with slightly developed area and broad ribs separated by deep, narrow furrows. Anisactinella ; forms with alternating ribs, area and elevated deltidium. The duplication of the spirals has also been observed in other Triassic genera, notably Koninckina, Suess, and Amphiclina, Laube;* shells differing from Katseria and its Triassic allies in so many other points of structure that a close phyletic connection between them seems highly improbable. Genus RETZIA, King. 1850. PLATE L. 1845. Terebratula, us Vbrmboil. Bull, de la Soc. geol. de France, second sei„ vol. xi, p. 471, pi. xiv, figH. 10 a-d. 1850. Retzia, Kino. Moiiogr. Permian Fobs. Kiigland, p. 137. 1854. Retzia, Davidson. Introd. British Fossil Brachiopoda, \i. 88, pi. vi, fig-. 77. 1886. ijetzio, (Eh LKRT. Annales Sci. Geol., volxix, No. 1, p. 24, pi. xi, figs. 11-19. " A Spiriferidia ; in general oval longitudinally ; ribbed or striated ; with long punctures. Large valve foraminated at or near the apex of the umbone ; with a triangular area, and a closed fissure. Type Terebratula Adrieni, De Ver- neuil." (King, Monogr. of the Permian Fossils of England, p. 137.) The term Retzia has come into general use as a designation for palaeozoic brachiopods which have an elongate-ovate form and radially plicated exterior. * See Ladbb, Die Fauna der Scbichten yon St. Cassian, Zvreit. Abtheil., p. 28. 1865. Bbbchbr, American Journal of Science, vol. xl, p. 211, pi. ii. 1890. 104 PALAEONTOLOGY OF NEW YORK. Many of the species originally included under this designation have been re- moved by the establishment of such generic divisions as Rhynchospira, Trema- TOSPIRA, Edmetria ; but, as the determination of generic values in all these fossils is usually attended with difficulties, it is highly probable, and indeed cer- tain that there are several distinct types of generic structure represented among the commoner species referred to Retzia. It will be necessary to determine the value of this genus from the characters of the species Terebraiula Adrimi, designated by Professor King as its type ; and our observations upon it lead to the belief that, strictly regarded, it presents a type of structure of rare occurrence, and with present knowledge no other species can be placed in the same association. Terebratula Adrimi was described by de Verneuil in 1845* from the lower Devonian of Spain, but our fuller knowledge of the species is due to the de- scriptions and figures given by Dr. CEhlert, who has identified it from the lower Devonian of the Departement de la Sarthe, Sable, Brulon, etc., France, f With the help of Dr. (Ehlert's published work and with his most consider- ate personal assistance, J we have made an earnest endeavor to develop the structure of the brachidium in this species. Unfortunately the specimens accessible were filled with a hard, opaque calcareous material, and such details as have been made out were obtained by the process of serial transverse section- ing. The nature of the interior of the brachial valve and the structure of the hinge-plate had already been demonstrated by CEhlert, and the results obtained in regard to the structure of the loop are so peculiar as to require corroboration, which the material at hand does not permit. The following account of the characters of the species represents the sum of our present knowledge of the genus. • Bulletin de la 8oci«t6 gfol. de Prance. 2d S6r., torn. 11, p. 471, pi. xiv, figs. 10, a-d. ' t See (Eblrrt ; Etudes sur quelques FoBsiles dfivoniens de I'Ouest de Fiance ; Annales Sci. G6ol., U xix, No. 1, p. 24, pi. xi, figs. 11-19. 1886. { Appreciating the necessity of making a thorough study of this rare species, we twice applied to Dr. (EiiLKRT for spe<;imens, ami he has most generously met these requests, not only with a number of examples from the Departement de la Sarthe, hut with copies of unpublished sketches of sections. This genei-osity •nd apirit of helpfulness is most cordially acknowledged. BRACHIOPODA. 105 Shell elongate-oval, rather broad over the pallial region. Surface covered with rather coarse, angular, usually simple plications. There is a trace of an indistinct median sinus on the pedicle-valve in which the plications are slightly smaller than those adjoining. The umbo of the pedicle-valve is incurved and its apex truncated by a circular foramen. The deltidium is triangular, flat, or arched by the incurvature of the beak ; the deltidial plates are tirmly anchyl- osed into a single piece and the original line of symphysis is represented by a thickened ridge. The edges of the cardinal area are well defined, but not alate on either valve, the beak and area of the brachial valve being entirely concealed by incurvature. The cardinal slopes are broad and smooth. On the interior of the pedicle-valve the teeth are rather small, and are supported by thin lamellae which traverse the umbonal cavity and rest on the bottom of the shell. These lamellae are produced forward for a short distance, limiting, posteriorly, the muscular area. The apical portion of the umbonal cavity contains a longitud- inal tube attached by one side to the inner surface of the deltidium. Just within the outer opening of the foramen this tube appears to have been closed on all sides, but further toward the cardinal margin it becomes split along the back or outer surface, diminishing in size downward and disappearing entirely before reaching the hinge-line. (In the accompanying figures of transverse sections, 80-83 are from a single specimen, 84, 85 from another, and 86-98 from a third.) In sections made across the vertical foramen it is seen that the tube extends within the deltidium and forms a subcircular enfolding of testaceous matter from the margins of the foramen. This organ is similar to that elsewhere described in the genera Hostedia and Acambona, but it appears to be more highly developed and longer in Retzia than in either of these. 106 PALEONTOLOGY OF NEW YORK. FlQ. 80. no. 81. FIO. 82. FIO. 8S. FIG. 84. FlO. 8S. Tig*. 80-8S. Settia AdriaU, ile Vcrncull. Consecutive sections to show internal structore of the nmbonal regions. Fig. 80. Oalline of tlie shell, showing location or next three sections. Ft|t. 81. Section across opening of foramen, with nmbonal tabe open on the baclc. Fijr. 81. Section farther down, showing attachment of the remnants or the tube to the deltidial plates. Pig. 8S. Section near the hinge, showing last traces of tube adherent to the thickened deltidial plates. Figs. 81, 8S. Sections from another individual, one across the foramen, the other beneath it ; showing the continuity of the tube. (0.) V^ Fig. 86. FJO.'ST. no. 88. FlO. 89. Fig. 90. Fio. n. Fig. 03. Fio. 94. Fig. 99. FIG. 9«. Fig. 97. Figs. 86-98. Retzia ddrieni, de Verneuil. FIG. 98. Fig. 86. Section just below the foramen; showing the entire umbonaltubo. Fig. 87. Showing the adherence of the tube to the still divided and discrete deltidial plate.'*. Flgi.88, 89. Sections at the umbo of the brachial valve; showing the internal coalescence of the deltidial plates, and the open tube. Fig. 90. Showing the dental lamellie, and the median septum in the brachial valve. Fig. 91. Section Just above the apex of the brachial valve; showing the last traces of the deltidial plates, which are here free. Fig. n. Section at the apex of the brachial valve. Fig. tt. Section cutting the posterior extension of the median and lateral lobes of the binge-plate. Fig. 91. The same features further down; showing also the appearance of the teeth, and the remnants of the dental lamellas bordering the muscular area of the pedicle-valve, ng. 9S. Section through the center of the hinge-plate; showing also the development of the dental socltets. Fig. 96. Section showing the ante-median crest of the binge-plate. Fig. 97. The anterior edge of the hinge-plate and its supporting septum. Fig. 96. Section in fkx>nt of the hinge-plate; showing the crura and median septum. (o.) BRACHIOPODA. 107 In the brachial valve the hinge-plate is subquadrate on its upper surface, its posterior margin somewhat crescentic, the horns of the crescent extending into the ambonal cavity of the opposite valve ; this character, however, is not so highly developed as in Eumetria. The structure of this plate appears to be essentially similar to that of Hustedia ; at all events, the tent-shaped crural supports of Eumetria are absent ; there is, however, no trace here of the lig- ulate, curved process which occurs in Hustedia, but the median portion of the upper faco is convex and the lateral portions deeply grooved and bounded on the outside by the elevated crural bases. The hinge-plate is supported by a strong median septum which extends for nearly two-thirds the length of the valve. It is most highly elevated near the middle of its length, where it ex- tends vertically about one-fifth of the distance across the internal cavity; thence it tapers rapidly to its anterior extremity. The brachidium has been reconstructed from serial transverse sections of the shell in several directions, and the following description may be relied upon as approximately accurate. The umbonal blades of the primary lamellae are comparatively narrow and considerably incurved at their apices, where attached to the long crura, as in Eumetria. The loop is situated well forward, just behind the center of the lamellae ;* its lateral branches are erect and long ; tliey narrow with a slight twist just above their origin, as in the genera Rhynohospira and Trematospira, then broaden, curving outward and no. 99. FIG- lOO- The loop of Retzia Adrieni, de Vernenll, as reconstructed from consecutive sections, (C.) • It will be observed that in the athyroiii and i-etzioid g-enera, with the exception of Nuclkospiha, bioad umbonal bliuies and a i)Osterioi- i)08ition of the loop charactenze the Carboniferous forms, while in the earlier faunaH the species have nai-row primary lamellse and a medially situated loop. 108 PALAEONTOLOGY OF NEW YORK. thence inward to their point of union. The stem is short, making an angle with the lateral branches, and is directed backward. It reaches the level of the crura at a considerable distance in front of them and is there bifurcated, each arm making a slight double or sigmoid curve. These arms are, however, too short to reach the umbonal blades. The stem itself is continued for a short distance above the point of bifurcation. The spiral ribbons make ten or eleven volutions in full-grown individuals. Fimbriae are absent from both the spirals and loop. Accepting this reconstruction of the loop as correct, this organ proves to be precisely what might be anticipated in this Devonian genus ; it resembles that of the prei'xisting genera Rhynchospira and Trematospira in its position on the primary lamellae, its erect attitude, as well as in the slight twist in the ribbon near its origin, while the length of the lateral branches and the terminal bifur- cation are like Eometria. From Rhynchospira the genus further differs in the presence of the split tube in the umbonal cavity, which feature seems to attain its highest development among these retzioid genera. There are also some additional differences of secondary importance in the structure of the hinge- plate in these two genera. Retzia Adrieni is, therefore, a type of distinct generic structure, of which, as already remarked, no other representative is at present known It is quite certain that the genus is not a member of the palaeozoic faunas of America, so far as known, the so-called Retzias of our Devonian being mostly referable to Rhynchospira. Genus RHYNCHOSPIRA, Hall. 1859. PLATE L. 1852. Atrypa, Hall. Palaeontology of N. Y., vol. ii, p. 280, pi. Ivii, fig. 7. 1857. Waldheimia, Hall. Tenth Ann. Kept. N. Y. State Cab. Nat. Hist., pp. 87-«9. 1859. Jihynchogpira, Hall. Twelfth Ann. Rept. N. Y. SUte Cab. Nat. Hist., pp. 29, 30, figs. 1-6. 1869. Rhynchospira, Hall. Palseontology of N. Y., vol. iii, pp. 213-217, 484, 485, pi. xxxvi, figs. 1,2; pi. xxxvi A, fig. 1 ; pi. xcv a, figs. 1, 7-11. 1861. Retzia, Billisos. Canaecies is referred to the genus Acamboka in db KoNrNCK's last woik on the Faune du Calcaire Carbonifere de Belgique ; Brachiopodes, Explic, pi. xxii, figs. 25-31, 1889. Most of the figures given in this work, however, show a vei-y clearly developed foramen, on the absence of which the genus Acambona was based. Waaobs, on the other hand, has more recently suggested that this rare species may prove con- generic with his Uncinella iTidica. 120 PALJEONTOLOGY OF NEW YORK. more like those ofEumeiria Vemeuiliana, Hall. The hinge-plate bears two short processes on its posterior edge, which extend only for a short distance into the umbonal cavity ; this organ is very imperfectly known, but as far as under- stood it seems to be nearer in structure to that of Hustedia than of Eumetria. Acambona prima was described from the lower beds of the Burlington limestone, and it is quite probably identical with the species described by Professor Swallow, at an earlier date, as Retzia Osagmsis, from the Choteau limestone. . Genus HUSTEDIA,* gen. nov. PLATE IJ. 1868. Terebratula, Marcoo. Geology of North America, p. 51, pi. vi, fig. 11. 1859. Retxia, Mbbk and Hatdbn. Pi-oc. Acad. Nat. Sci. Philadeli)hia, vol. iii, second ser., f. 27. 1860. Retzia, McChksnby. New Palaeozoic Fossils, p. 45. 1866. Relzia, Gbinitz. Carbon iind Dyas in Nebraska, p. 39, pi. iii, fig. 6. 1868. Relzia, McChbsnby. Trans. Chiei-iod of more than twenty years, as Rejircsentativc in the Assembly of the Legislature of New York, zealously espoused the interests of the Paleontology, and of eveiy other department of the Natural History of the State of New York. A wise legislator and educator, a faithful and unswerving fnend and counsellor of many years, his name deMrves to be spoken with respect and reverence wherever geologic science shall be taught or studied, throughout the civilized world. BRACHIOPODA. . 121 structure of the hinge-plate and of the urabonal cavity of the pedicle-valve. The latter contains an internal tube attached by one side to the deltidium, and split along the opposite side, a precisely similar structure to that observed in Retzia Adrimi and Acambona Osagensis, though not so highly developed as in the first of these. This structure is of so frail a nature r^ that it is difficult to preserve it in prepared inte- ikj riors of the valve, but it always reveals itself in transverse sections of the beak near its apex. The structure of the hinge-plate has been quite accu- outime pronie o/"™«. i.f<»-mom-, Mar- rately described by Derby* from the interiors of 7^\::'l^:it:TrZ'\:TeZ Eumetria pmctulifera {= Hustedia Mormoni) obtained TllTJZlm.'ZT"T) '° from the limestone of the Coal Measures at Bomjardim, on the Amazonas. Dr. Waagen has also given a very accurate account both of the hinge-plate and the brachidium in species which he has referred to EuMETRiA.f The hinge-plate, as it appears in the preparations of Terebraiula Mormoni, is con- stituted as follows : It is erect and recurved into the umbonal cavity of the pedicle-valve, projecting considerably beyond the hinge-line ; the upper face is convex and elevated medially, the posterior margin sinuate and crescentic, though the horns of the crescent are very short; two deep converging grooves pass over the upper face, and outside of these, on the lateral margin of the plate are strong lobes which bear the erect, slightly recurved crura ; from the crural bases the lateral margins curve downward to the bottom of the valve and form the socket walls. At the base of the cardinal process and in the median line arises a free, slender, ligulate process which curves upward and backward with a somewhat less curvature than the plate, and rises to the high- est point attained by the latter ; the inner surface of this process is deeply grooved, and at its base it is supported by a median septum which extends for one-third the length of the valve. There is no tent-shaped structure for the support of the crura as in Eumetria. Dr. Waagen has suggested the similarity of this peculiar ligulate process to the visceral tube occurring in many forms of Athyrib, but it is evident from its * Bulledn Cornell Univereity, vol. i, No. 2, pp. 5, 6. 1874. t Salt^Range Foesils ; Brachiopoda, p. 486. 1883. 122 PALEONTOLOGY OF NEW YORK. form and acute apex that it could not have been tubular, and, besides, there is no evidence of a perforation in the plate. The spirals have the same structure as in En- METBIA, and Debbt has shown that the posterior margins of the coils are fimbriated. The loop, also, is quite similar to that of Eumetria Vernmiliana. Waagen has represented it in Eumetria (Hustedia) grandicosta, Davidson, as terminating in a short. Loop or j«. op of Parazpgahiraula, um. The interesting combination of characters is best represented in the species cited, Trematospira hirsuta, Hall, of the Hamilton group,* and with the exception of the structure of the loop, the distinctive features were well illustrated on Plate XLIII of Volume IV of the Palaeontology of New York. There is but one other species which can properly be placed in the same association, namely, the Waldheimia or Trematospira Deweyi,\ Hall, of the Lower Helderberg fauna. This form is very similar to .Parazyga hirsuta in external characters, its surface being finely plicated and with a median fold and sinus. Whether it was orig- inally hirsute can not be decisively determined on account of the usual silicified condition of the shells. The beak of the pedicle-valve is so closely incurved that the foramen is almost or wholly obscured, and the deltidium has the appearance of a concave excavation in the solid substance of the shell, having thus almost precisely the structure occurring in Nucleospira. The hinge-plate » The 8|)ecie8 has also been identified in the Corniferous limestune of Louisville, Ky., and elsewhere, t Name iU- 1 il, i Bifida lepida, (ioUUMas. IFIDA, and on the basis of this also that ^^^ brachidium as represented by Mr. Davidson compared and classified the shell davidsox from preparations by glass. with the genus Whitfieldia (== Meristina.) The accompanying figure shows the structure of this organ as described by him. A careful study of this shell II has led to a quite different result in regard to the structure of the loop. These observations have been made not only from translucent prepara- tions, but also by consecutive sectioning of opaque specimens, and the conclusions verified by frequent repetition of the process. The accompanying figures are of sections made from opaque specimens cut in a plane vertical to the longitudinal axis of the shell, the series * Supplement to British Devonian bracbiupoda, p. 27. t Transactions (if the Geological Society of London, second ser., vol. vi, p. 386. 1840. t British Devonian Brachiopoda, p. S2. 1864. } Zeitschr. der deutschen geolog. Gesellschaft, vol. xxiii, p. 559. 187 J. I From specimens from Gerolstein in the Eifel, furnished by Dr. E. Holzapfbl, of Aachen. 132 PALEONTOLOGY OF NEW YORK. beginning at the beak. Figures 114, 115 show the cross-section of the broad, stout hinge-plate, its convex central area and its elevated crural bases; in figure 115 is a faint indication of the median ridge in the upper or pedicle-valve. In figure 116 the crural bases are apparently merged with the socket walls, the hinge-plate has become depressed, and its median S FtO. 111. FIO. 115. Fio. 110. Fig. 117 Fio. 118. Fio. 119. FIU8. lU-119. Consecutive transverse sections of Anoplotheca (Bifida) IqHda, Goldfoss. (c.) Fig. 114. Section just below apex of pedicle-valve ; showing the teeth and the rorm of the liinge-plato or cardinal process. Fig. IIS. Section a little ftirthor forward; showing the elevation of the socket walls and the beginning of the median septum in both valves. Fig. lie. Section at anterior edge of liinge-plate. Fig. 117. Section cutting the posterior volutions of the spirals; showing the height of the septum in the brachial valve and the thickened median ridge in the pedicle-valve. Fig. 118. Section through the loop ; showing its lateral branches and a portion of its erect, simple stem, and also the grooved surface of the median ridge in the pedicle-valve. Fig. 119. Section along the stem of the loo|> and slightly back of the junction of the lateral branches; showing the articulation of the stem with the grooved ridge of the upper valve, and the height of the median septum supporting the loop. Figs. 111-118 are from the same specimen ; fig. 119 from another ex- ample. elevation has taken the form of a low septum; in fig. 117 the median septum of the brachial valve is very prominent, the median ridge of the opposite valve undivided, and the lamellae of the first volution of the coils and the stem of the loop are shown. This figure shows the manner in which the loop is supported by the median septum ; also a portion of the vertical stem of the loop, and the grooving of the median ridge in the pedicle-valve ; and in fig. 119 the stem of the loop is seen to be produced to the inner surface of the pedicle-valve and its apex fitted into the groove of the median BRACHIOPODA. 133 ridge. The mutual relations of the different parts of the internal apparatus Fig. l-iO. FIG. 121. Figs. 120, 121. The brachidium of Anoplotheca {Bifida) lepida. (c) Fig. 120. A lateral view, showing the relations of the loop to the median septam and ridge. Fig. 121. A poeterior view from behind. are better seen in the accompanying constructive figures (120, 121), one representing a view of the interior from the side, the other from the umbonal region. This structure shows an admirable adaptation in the loop for resistance to strains; the slotted median ridge of the pedicle-valve is short and thick, extending for about one-half the length of the shell, and is most deeply excavated at the point where the stem of the loop is inserted. (See figure of the interior of this valve given on Plate LII, fig. 19.) The cardinal process in this species has not, so far as we are aware, been described or figured, but our sections show that it is quite similar to that of Anoplotheca venusta, as described by Sandberger and Suess. The latter species also has the median septum in each valve, and though the character of its loop is not known, it will be shown that in similar forms from American faunas this organ possesses the same structure as in Terebratula lepida. It is highly improbable that two species, so closely similar in external and internal characters as Anoplotheca venusta and Bifida lepida, and coexisting in the same fauna, are not congeneric. Therefore, with our present knowledge, it seems necessary to conclude that the term Bifida is altogether synonymous with A.N0PL0THECA. 134 PALAEONTOLOGY OF NEW YORK. SoBOENUS CGELOSPIRA, Hall. 186:1 TLATK LIII. 1839. Atrypa, Sowekby. Murchison's Silurian System, p. 637, pi. xx, fig. 7. 1841. Atrypa, Cosrad. Geol. Surv. N. Y.; Ann. Rept. Palseont. Dept., p. 54. 1843. Atrypa, Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 71, fig. 4. 1852. Atryita, Hall. PalsEontology of N. Y., vol. ii, pp. 74, 75, pi. xxiii, figs. 9-11. 1855. HemUhyris, McCoy. British Palieozoic Fossils, p. 201. 1857. Ltptocalia, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 107. 1859. LeploecHia, Hall. Palaeontology of N. Y., vol. ill, p. 24.5, pi. xxxviii, figs. 1-7. 1863. Calospira, Hall. Sixteenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 60. 1866. Leptoctelia, Billinqs. Catalogue of Silurian Fossils of Anticoati, p. 48. 1866. Atrypa, Davidson. British Silurian Brachiopoda, p. 136, pi. xiii, tigs. 23-80. 1867. Ccdoxpira, Leptoccdia, Hall. Paleontology of N. Y., vol. iv, pp. 328-330 (fig. 1), 365, pi. lii, figs. 13-19 ; pi. ivii, figs. 30-39. 1884. Leplocalia, Davidson. General Summary, p. 424. The term Ccelospira was proposed in the Sixteenth Annual Report of the New York State Cabinet of Natural History (p. 60) for the Lower Helderberg species C. concava, Hall, which originally had been referred* to the genus Lep- TOCCELIA. The reason for the separation was expressed in a figure of the bra- chial apparatus accompanying the first use of this name. The spirals were represented as loosely coiled and almost in the same plane, the apices being very slightly elevated and directed outward ; the loop posteriorly situated, broad and continuous, very similar to that of Zygospira. The Leptocalia concava is a small piano-, or subconcavo-convex shell, covered with rather numerous simple or bifurcating plications. The pedicle-valve has distant teeth arising from the lateral cardinal slopes, and in front of the umbonal cavity are a pair of rather deep oval diductor scars, which embrace the anterior extremities of two narrow, less excavated adductors. These are separated by a narrow, more or less conspicuously developed median ridge as in Terebratula venusta and T. lepida. The cardinal process has the same structure as in Anoplotheca, consisting of a central portion curved backward to, or slightly beyond the hinge, and faintly bilobed on its posterior extremity. The crural bases are consolidated with the central process and are continuous with the socket walls. There is a stout • P»la»ntology of New York, vol. iii, p. 245, 1859 ; and Tenth Rept. N. Y. State Cabinet, p. 107, 1857. BRACHIOPODA. 135 median ridge dividing the muscular impressions and supporting the cardinal process. The structure of the brachial apparatus has been carefully re-examined, and it is found that the crura are slender and rather long, slightly converging toward their apices, forming an acute angle where they meet the primary lamellae; the latter turn outward and backward, remaining widely separated throughout their extent. The coil is lax, the ribbon making but about three volutions, and the cones, though very slightly elevated, have their apices directed outward, toward the lateral slopes of the pedicle-valve. These shells vary considerably in convex- ity both naturally and from accidental compression, and where the internal cavity is shallow the spirals may appear to be coiled almost in oblique planes. The umbonal curves of the primary lamellae are very broad and stout ; the loop arises on their posterior limb, broad and strong, its lateral processes curv- ing gently forward and thence upward, not as in Zygospika, nor as represented in the original figure of these organs in Calospira concava, but elevated and acutely angulated at the apex. Beyond the junction of the lateral processes the loop is continued as a simple stem which is inclined backward and may have been extended to the surface of the internal ridge on the pedicle-valve, as in Terebratula lepida. FlO. 122. FIO. 123. Fig. I2S. Tbe brichidlam of Calotpira concava. Hall. T\g. 123. Proflic, BhowitiK the eleration of the loop. The stem of the loop to probably broken and therefore shorter than Is natural. (^') In front of the base of the loop the primary lamellae become at once narrow and delicate, and it not infrequently happens, in preparations of the interior, 1S6 PALEONTOLOGY OF NEW YORK. that the more fragile portions of the ribbon are lost, leaving only the umbonal blades and the loop. The same details both of exterior and interior structure have been observed in the species Ccelospira Camilla, Hall, of the Corniferous limestone of New York and Canada, and, with the exception of the brachial apparatus, in the Atrypa acutiplicata, Conrad, of the same fauna. It is clearly evident that the structure in the species of Cojlospira here mentioned, is essentially the same as in Anoplotheca venusta and A. {Bifida) lepida. The only material difference, that can now be indicated between these forms, is one of greater geological than biological significance; the later, or middle Devonian forms (Anoplotheca) being more convex, more coarsely and sparsely plicated and more strongly striated concentrically. Upon this basis of distinction the name C(elospira may be retained with a subgeneric value. There are a few species in the Clinton fauna which have the outward expres- sion of Ccelospira, and agree with it in the structure of the articulating appa- ratus. These species are Atrypa plicatula, Hall, A. planoconvexa, Hall, and A. hemispharica (Sowerby), Hall {= Leptocalia hemispherica, Davidson). The brachidium in these forms is not yet known, and their reference to Ccelospira is therefore provisional. Genus LEPTOCCELIA, Hall. 1859. PLATE Lin. 1841. Atrypa, Coitbad. Qeol. Survey N. Y. ; Rept. Palseont. Dept., p. 66. 1846. Atrypa, Morris and Sharps. Quart. Jour. Geol. Soc, vol. ii, p. 27B, pi. x, fig. 3. 1856. Orthin, Sharpe and Salter. Trans. Geol. Society London, second ser., vol. vii, p. 203. 1857. Leptocalia, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. History, p. 108. 1859. Leptocadia, Hall. Palaeont. of N. Y., vol. iii, pp. 449-4.52, pi. ciii b, fiffs. 1 a-g ; pi. cvi, figs. 1 a-f. 1861. Ortliis, Raltkr. Quait. Jour. Geol. Society, vol. xvii, p. 68, pi. iv, fig. 14. 1868. Leptocadia, Mbbk and Wobthkn. Geol. Surv. Illinois, vol. iii, p. 397, pi. viii, figs. 3 a~c. 1892. Leptocalia, Ulrich. Palaozoische Verstein. aus Bolivien: Neues Jahrb. fUr Mineral., etc., Beilagebnd. viii, p. 60, pi. iv, figs. 9 a, b, 10-13. The typical species of this group is L. flabellites, Conrad, of the Oriskany sandstone; a shell which differs, as far as its structure is known, from Ccelospira concava, only in its greater size and coarser, simple plication of the surface. In general contour, structure of hinge, cardinal process, muscular scars and inter- BRACmOPODA. 137 nal septa, it agrees throughout with Anoplotheca and Ccelospiea. In the original diagnosis of Leptoccelia, L. Jiabellites was described and figured as pos- sessing a terebratuloid loop. It was, however, distinctly stated that the evi- dence of this structure was confined to a single specimen containing cavities in its filling of quartz, which corresponded to the restoration given. Subsequent investigations have not corroborated this observation. The specimens of this species are not favorably preserved for the retention of the brachial apparatus, those from Cumberland, Maryland, being replaced by silica and often filled with coarsely crystallized quartz, while those from New York, Gaspe and the South American localities are usually in the form of casts in an arenaceous sediment. Later observations have not shown any trace of the organ described, and it is highly improbable that a species agreeing in all known points of structure with the spirigerous groups just discussed, and having also a fibrous shell structure, should possess a terebratuloid loop. Ref- erence has been made to the fact that in Calospira concava the stout umbonal blades of the primary lamellae and the loop are frequently all that is retained of the brachial apparatus, the rest of the brachidium being very delicate ; the parts thus retained are by themselves certainly suggestive of terebratuloid structure, and not unlike the loop ascribed to L. flabellites. With our present knowledge it would be unwise to separate Leptoccelia too widely from Anoplotheca and C(elospiba. There are but two other species which can safely be referred to the group of L. flabellites, namely, L. dichotoma and L. fimbriata, Hall, also ■ from the Oriskany fauna at Cumberland. The latter shell possesses a peculiarity in the extension, from between the cardinal extremities of the valves, of the inner lamina of the shell substance in the form of a row of spinules having the appearance of matted cilia. (See Plate LIII, figs. 47, 50.) Leptocalia flabellites, the type species, is remarkable for its wide distribution. Like Tropidoleptus carinatus and Vitulina pustulosa, it abounds in the lower Devonian strata of South America. Morris and Sharpe described the species under the name Atrypa palmata, from material collected by Darwin in the Falkland Islands ; Salter described it as Orthis Aymara, from various localities 138 PALEONTOLOGY OF NEW YORK. in the cordilleras of Bolivia; and Ulrich has cited a large list of additional localities which indicate its general and abundant occurrence in that country. It hiis not been reported in the rich lower and middle Devonian faunas of the Amazonas, but occurs at Ponta Grossa, Brazil. Salter identified it as Orthis palmata among some palaeozoic fossils from South Africa, and Ulrich suggests that a similar shell from the Cape, referred to by Murchison* and subsequently by DE VernecilI as Orthis calladis, is probably this species. Of the three species so intimately associated in the Bolivian Devonian, Leptocalia flabellites, Vitulina pustulosa, and Tropidoleptus carinatus, the last is the only one which occurs in European or Asian faunas; all occur in South Africa in faunas which are probably of lower Devonian age. In North America, this association is broken, and Leptoccelia disappears with the early Devonian ; Tropidoleptds and Vitulina appearing only with the introduction of the Hamilton fauna. Genus VITULINA, J Hall. 1860. SUPPLEMENTARY PLATE. 1860. Vitulina, Hall Thii'teenth Rept. N. Y. State Cab. Nat. Hist., p. 72, figs. 1, 2 ; p. 82. 1862. VUulina, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., p. 187. 1867. Vitulina, Hall. Palaeontology of New York, vol. iv, pp. 409-411, pi. Ixii, figs. 1, a-i. 1874. Vitulina, Rathbds. Bull. Buffalo Society of Natural Sciences, vol. i, p. 255, pi. ix. 1876. Vitulina, Dsrbt. Bull. Museum Harvard College, vol. iii, No. 12, p. 282. 1881. Vitulina, Rathbcn. Proc. Boston Society of Natui-al History, vol. xx, p. 36. 1890. Vitulina, Derby. Archivos do Museu Nacional do Rio de Janeiro, vol. ix, p. 76. 1891. VUulina, Ulrich. Neues Jahrbuch fur Mineralogie, etc., p. 273. 1892. VituliTia, Ulrich. Neues Jahrbuch fUr Mineralogie, etc., Beilageband iii, p. 71, pi. iv, figs. 26-29. The nature of the widely distributed little species Vitulina pustulosa, Hall, has never been fully understood. When the generic characters were first described their similarities to both Leptoccelia and Tropidoleptus were sug- gested, but these were not reiterated with the more detailed description and * Silurian System, p. 701. t Bull. .Society G6ol. France, vol xi, p. 166. 1840. I This name is said liy Dall to have been employed by Swainson in 1840 for a genus of Qastropoila, but it does not appear in the later conchological manuals. See Dall, Bull. U. S. Nat. Mus. No. 8, p. 75. This is possibly in ei-ror for Vitolarta, Swainson. 1840. BRACHIOPODA. 139 illustration of V. pustulosa in 1867* Its general external resemblance to Tropidoleptus and its almost universal association with that genus in Devonian faunas have led to a tacit concession, on the part of some authors, of structural relations in the two genera. All observations upon Vitulina have heretofore been based upon separated valves or casts of their interiors. Specimens in which the valves are retained in their normal position are of extreme rarity, and it is from such an example, obtained in the Hamilton shales of Alden, New York, that we have succeeded in demonstrating the species to be spiriferous, and that its structural characters ally it closely to the genera which have just been discussed. The distinctive features of the genus may be summarized as follows : Shell of rather small size ; plano-convex in contour, transverse, the hinge- line making the greatest diameter of the valves. The pedicle-valve is convex, its umbo scarcely elevated and its apex not prominent or incurved. A cardinal area is highly developed, and is divided medially by an open, triangular delthyrium, which bears no traces of deltidial plates in any condition that has been observed. The delthyrium is very wide, its base covering more than one-third the extent of the hinge-line. The teeth are blunt, thickened, and not supported by dental plates. The scar of the pedicle-muscle is distinctly defined, but those of the other muscles are obscure in their limitation. Under the most favorable preservation, there appears a posterior flabelliform pair, situated just in front of the pedicle-scar, and in advance of these a median scar enclosed by two anterior diductor impressions. There is, at times, a low median ridge, which is purely muscular in its origin. The brachial valve is depressed-convex or flat ; it bears a narrow cardinal area coextensive with that on the opposite valve. The delthyrium is wide and open, and when the conjoined valves are viewed from behind, the cardinal pro- cess and socket walls are clearly seen through the wide pedicle-passage. The former of these, the cardinal process, is a straight, simple apophysis, like that in Anoplotheca and C(EL0Spira ; and the socket walls, which are also the bases of the crura, are short, but prominent and elevated, bordering deep and narrow * Palaeontology of New York, vol. iv, pp, 409-411, pi. Ixii. 140 PALEONTOLOGY OF NEW YORK. dental sockets. The brachidium consists of loosely coiled spirals of about four volutions, the cones having their apices directed toward the lateral margins of the valves. On the dorsal side the primary lamellae are close together, but on the ventral side they are wide apart, this fact indicating that the bases of the spirals do not lie in parallel planes but converge toward the brachial valve, so that the slope of the cones, which are somewhat appressed laterally, is essen- tially that of the lateral slopes of the pedicle-valve. The character of the loop has not been ascertained. The muscular impressions consist of four distinct adductor scars which are separated medially by a low, thin ridge. Surface of both valves covered by a few coarse plications, continuous from the umbones to the margins. Of these there are four or five on the lateral slopes. On the pedicle-valve the median pair is the strongest, and forms a sort of double fold with a low sinus between them. On the brachial valve there is a corresponding low median sinus, which contains a simple or double plication. The exterior is covered with fine elevated radiating lines which are usually interrupted to form radiating rows of elongate, lachrymiform pustules. Shell substance fibrous, impunctate. ViTDLiNA now takes its place quite naturally in close association with Ccelo- SPIRA and Leptoc(ELIA. Yet the remarkable development of the cardinal area on both valves and the great open delthyrium are features which suggest an alliance with the orthoids. In so late a representative of this group of spiriferous genera the occurrence of these characters may probably be inter- preted as a single recurrence of an early phase of development. Like the genus Tropidoleptos, with which Vitulina is closely associated wherever it occurs, the latter appeared suddenly, attained a very prolific develop- ment, and as abruptly disappeared. In South America it appears with Tropido- lepttis carinatus wherever Devonian faunas have been recognized, and perhaps more abundantly in the lower Devonian, in association with Leptocalia palmata, Salter, or L.flabellites, Conrad, than in those faunas considered equivalent to the Hamilton shales of New York. Dr. 0. A. Derby, in reporting the species from the Province of Matto Grosso, Brazil, says : " This generic form would seem to be peculiarly a South American one, since, while it is rare and only very locally dis- BRACHIOPODA. 141 tributed in North America, and has apparently not yet been recognized in Europe, it appears in every South American collection of Devonian fossils that has come under my notice. On the Amazonas it is one of the most abundant and characteristic shells in both the lower (Maecuru) and upper (Erere) divisions. It occurs also in the collections made by Prof Alex. Agassiz at Lake Titicaca, in Bolivia, and by myself at Ponta Grossa, in the Brazilian province of Parana, although in both these cases, as in that of Matto Grosso, only a mere handful of fossils was obtained."* A. Ulrich reports that the species was also found in Bolivia by Steinmann, near Tarabuco, and by Sir'BEL in the valley of the Rio Sicasica.f The same author has identified this shell in close association with Leptocalia flabellites, among fossils collected by ScHENCK in the Bokkeveld Mountains, in South Africa. In North America, Vitulina pustulosa is restricted to the middle Devonian, occurring only, so far as known, in the soft shales of the Hamilton group in western New York. Even here it is not generally diffused, but its gregarious habit is evinced by its abundance in the few localities from which it has been reported. Gends a N a B a I a , Clarke. This name has been introduced in an unpublished account of the "Upper Silurian Fauna of the Rio Trombetas, Province of Pard, Brazil,"^ for a Silurian Fig. 121. Hu. J25. Flu. 1-26. Flo. 127. Figs. l-'4-127. Andbaia Paraia, Clarke. Fig. 121. Exterior, sliowiog Uie bractiial valve. Fig. 12.V Profile of a somewliat compressed specimen. Fig. 126. Interior of tlie brachial valve; showing the cardinal process, crura, dental socliets and septum. Fig. 127. Inlemal cast of portion of the pedicle-valve; showing the mnscalar scars. (c.) * Nota sobre a Geologia e Paleontologia de Matto Grosso, pp. 7B, 77. 1890. t Neues Jahrbuch fur Mineralogie, etc., Beilageband viii, pp. 71-73, pi. iv, figs. 26-29. 1892. J Arcbivoe do Museu Nacional do Rio de Janeiro, vol. x 142 PALEONTOLOGY OF NEW YORK. shell allied to Leptocalia fiabellites in the structure of its cardinal process and articulating apparatus, having, however, a highly convex brachial valve with a median septum extending one-half its length, two short, abruptly ending plications on the low median fold, upturned anterior margins, and explanate cardinal extremities. As far as the structure of its type species, Anabaia Paraia, Clarke, is known, it appears to be the precursor of the Devonian shells referred to Anoplotheca and Leptoccelia. Genus NUCLEOSPIRA, Hall. 1859. PLATE XLVUI. 1843. Atrypa, Hall. Geology of N. Y.; Kept. Fourth Dist., p. 200, fig. 3. 1852. Ortftli, Hall. Palaeontology of N. Y., vol. ii, p. 250, pi. Hi, fig. 1. 1857. Spitifer, Hall. Tenth Kept. N Y. State Cab. Nat. Hi.=;t., p. 57. 1858. Nucleospira, Hall. Twelfth Rept. N. Y. State Cab. Nat. Hist., pp. 24-26. 1859. Nueleospira, Hall. Palaeontology of N. Y., vol. Hi, pp. 219-228, pi. xiv, fig. 1 j pi. xxviii, b, figs. 2-19. 1860. Nucleotpira, Whitb. Jour. Boston See. Nat. Hist., vol. viii, p. 227. 1863. Nueleospira, Hall. Transactions of the Albany Institute, vol. iv, p. 226. 1867. Nueleospira, Hall. Palteontology of N. Y., vol. iv, pp. 278, 279, pi. xlv, figs. 33-57. 1879. Nueleospira, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p. 160, pi. xxv, figs. 22-28. 18S2. NHcleofpira, Hall. Eleventh Rept. State Geologist of Indiana, p. 301, pi. xxv, figs. 22-28. 1882. Nueleospira, Whitfiblp. Annals N. Y. Acad. Sciences, vol. ii, p. 194. 1884. Nueleospira, Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 147. 1889. Nueleospira, Nettblboth. Kentucky Fossil Shells, pp. 103, 104, pi. xxxii, figs. 1-4 j pi. xxxiii, figs. 7-9. Diagnosis. Shells usually small, subcircular in outline. Valves subequally convex, often gibbous or ventricose. Hinge-line very short, cardinal ex- tremities rounded. On the pedicle-valve the cardinal area is low and obscured by the incurvature of the beak. Only in very young specimens is the deltidium exposed, and it then consists of two plates attached to the lateral margins of the delthyrium; in mature individuals these plates are coalesced and incurved, the median suture is lost and the foramen covered ; the appearance of the deltidium is that of a triangular concave plate, limited by rather sharp dental ridges and covering the delthyrium for about half its length. The teeth are prominent, approximate, recurved at their tips, sup- ported by thickened bases but not by lamellae. Dental sockets very narrow. The muscular area is flabellate and extends for nearly one-half the length of BRACHIOPODA. 143 the shell ; it is composed of two elongate-ovate adductor scars enclosed by broad and radially striated diductors. A conspicuous median septum begins in the urabonal region and extends to within a very short distance of the anterior edge of the valve. In the brachial valve the hinge-plate arises with a vertical anterior face from the bottom of the shell; but just above the plane of the margins of the valve it is reflected in a curve so abrupt that its upper face becomes horizontal. The anterior face is concave and quadrate in outline ; the posterior face is subtriangular, flat or concave, and is frequently bilobed at its extremity. In profile the plate has a hook-shaped appearance; its posterior extremity being elevated considerably above the beak of the valve, and when the valves are in articulation, extending quite to the bottom of the umbonal cavity of the pedicle-valve. The crural bases are situated on the vertical face of the plate, just at the point of recurvature. The crura are slender, straight, long and rod-like, having a length equal to fully one-fourth that of the shell. They are attached at their tips to the inner surfaces of the primary lamellae. The primary lamellae of the spiral coils are greatly incurved and their apices close together ; their umbonal blades are very broad. The loop originates at about one-fourth the length of the lamellae, is inclined slightly backward, the lateral branches uniting directly in front of the apices of the lamellae, and forming a simple straight stem, which is continued beyond the opposite edge of the coil and almost to the inner surface of the pedicle-valve. The spiral ribbon makes from six to ten volutions, and the cones have their altitude in the transverse diameter of the shell. The muscular area is very narrow and elongate, the posterior adductor scars enveloping the extremities of the anterior adductors. They are divided into pairs by a median septum of the same extent as that of the pedicle-valve. Fine racemose vascular sinuses are sometimes retained over the pallial region of both valves. The external surface usually bears a low median sinus and fold on the pedicle and brachial valves respectively. The epidermal layer of the shell is usually, probably always, covered with numerous fine, short spinules; these. 144 PALEONTOLOGY OF NEW YORK. when removed, leave the surface with only regularly concentric growth-lines marked by papilloB which are the bases of the spinules. Type, Spirifera ventricosa, Hall. Lower Helderberg group. Observations. Ndcleospira is a well defined and very compact genus. Though not largely represented in species, it has a considerable vertical range, appearing in the middle Silurian .and disappearing probably in the middle or upper Devonian. • The genus is allied in some general respects to the genera which Mr. Davidson associated with it, under his sub-family NucLEospinw^, viz.: Retzia, Meristina, Eumetria and Trematospira, but the distinctive features of the brachidium bring it into closer association with Anoplotheca and C(ELbspiRA, notwithstanding the great differences in exterior. The spinul- ous surface, which appears to be common to all the species, is suggestive of Parazyqa and some forms of Athyris. The peculiar structure of the delthy- rial covering, resulting from a coalescence of the deltidial plates, is not unlike that of Eumetria and Trematospira, and the same extreme of modification is reached in Parazyga Deweyi. The imperforate hinge-plate is extravagant in its elevation and peculiar in form. Hitherto the character of the loop has not been accurately determined, and yet this structure is very simple ; a union of the lateral branches at a low angle and the continuation of an undivided straight stem across the interior cavity. The explanation of the various imperfect determinations of this part which have been given by different au- thors, is to be found in the fact that the long, slender crura, the broad umbonal blades of the primary lamellae and the lateral branches of the loop almost, and sometimes actually meet. Any detachment of the interior part of the shell, either intentional or accidental, is very likely to pass through this point of convergence and remove from the seven processes there approximating the simple continuation of the loop. This stem of the loop is continued beyond the bases of the spiral cones, and may reach the surface of the pedicle-valve, but it does not articulate in a slotted ridge in the similarly constructed loop of the genus Bifida or Anoplotheca, nor is its extremity bifurcated to em- brace the low median septum of the valve. The stem usually makes a large BRACHIOPODA. 146 angle with the lateral branches of the loop, and is deflected posteriorly ; its surface is generally cylindrical, but in Nucleospira concenirica it is considerably flattened. Fig. 128. Fig. 129. FIO. ISO. Fig. 131. Kg. 188. A preparation of NueUtapira ventricota, Hall; ihowing the ambonal blades, the loop and the form of the first Tolatlon of the spirals. Figs. 129, 130. The primary lamellae and loop of IfueUotpira ventrioota. Hall. Fig. 131. A preparation of NucUotpira concinna, Hall; showing onehall of the brachidium, the mode of attach- ment of the erurs to the ambonal blades and the fiattened stem of the loop. (c.) The structure of the hinge-plate and brachial apparatus is now known in the following species of this genus : N. pisum, Sowerby, of the Wenlock lime- stone; N. pisiformis, Hall, of the Clinton and Niagara group; N. ventricosa, Hall ; N. elegans, Hall, of the Lower Helderberg, and N. concinna, Hall, of the Corniferous and Hamilton groups. Besides these, the following American species have been described: N. concenirica and N. rotundata, Whitfield, of the Lower Helderberg group, and N. Barrisi, White, of the Kinderhook. A single individual of what appeared, from external characters, to be the species Nucleospira concinna. Hall, from the Corniferous limestone of the Falls of the Ohio, affords a surprising variation in the structure of the loop. The internal parts have the same development and mutual relations as in specimens of the species from the Hamilton shales, except that the stem makes a slightly 146 PALEONTOLOGY OF NEW YORK. anterior instead of posterior bend at its junction with the lateral branches, and each of these branches bears a single row of irregular, somewhat ramose pro- cesses directed toward the inner edges of the umbonal blades. What the sig- nificance of these processes may be is not evident from a study of the specimen. They do not appear to be of mechanical origin or due to crystallization of silica upon the lamellae, but may possibly indicate a pathological or excresential condition. Fio. 13>. loop of Nucltotpira, sp. ?, from the Cornirerous limeBtone at the Falle or the Ohio. (C. ) Genus CYCLOSPIRA, gen. nov. PLATE LV. 1842. Orthis, Emmons. Geology of New York ; Rept. Second Dist., p. 395, fig. 4. 1847, Atrypa, Hall. Paleontology of New York, vol. i, p. 139, pi. xxxiii, figa. 3 a-e. This proposed division is founded on the species, Orthis bisulcaia, Emmons {Atrypa bisulcata, Hall), of the Trenton limestone, which in external characters is very similar to the Dayia navicula, Sowerby, of the Wenlock fauna. It is indeed surprising to find that two species so nearly alike externally, should differ so essentially in internal features as to require their separation into groups which appear but remotely related. Atrypa bisulcata is a subtrihedral shell with a very convex pedicle-valve and a depressed brachial valve. The larger valve has a prominent umbo, the beak being closely incurved over the hinge, concealing both foramen and deltidium. The umbo is longitudinally keeled, but at about one-third the BRACHIOPODA. 147 length of the valve a median furrow begins on this ridge, widening ante- riorly, and thus making a double keel over the forward parts of the shell. The lateral slopes are broad and smooth, interrupted only in the umbo-lateral regions by a short fold on each side, originating at the beak and lying just within the margins. FlO. 133.^ FlO. 134. Front and proBle views of Cydotpira Usutcaia, Emmons. X 2. The brachial valve is slightly convex posteriorly, becoming concave medi- ally over the pallial region. The median sinus bears a low fold corresponding to the central groove of the opposite valve. On the interior of the pedicle- valve the shell in the umbonal region is very thick, and in this thickened portion the scar of the pedicle-muscle, and in front of it, the adductor scar is excavated. At the anterior edge of the muscular area the shell becomes suddenly and abruptly thinner, and thus that area lies on a well-developed, solid platform. In the brachial valve the hinge-plate is small and sup- ported by a low median septum which extends about two-thirds the length of the valve. The crura diverge slightly as they pass downward, making a very low curve or slight angulation at their union with the primary lamellaB. The spiral ribbon is very delicate and quite short, making but two and one-half or three volutions, which are almost circular. The interesting feature of these spirals is that they are coiled in planes nearly parallel to the vertical axial plane of the shell. The best of our preparations, which are transparencies, show quite clearly that the apices of the spirals are very slightly introverted, and the primary whorls are so close together that this slight introversion brings the apices into approximation. This deviation from the vertical is apparently quite normal, and is fully corroborated by the ZYGOSPiKA-like contour of the shell ; and yet it would require but slight mechanical or casual disturbance of 148 PALEONTOLOGY OF NEW YORK. the spirals to produce an equal inclination outwardly. As to the loop, there is as yet no satisfactory proof of its existence ; indeed, the evidence derived FlO. 185. FlQ. 186. The brachidiam'of Cydotpira bimlcata, Emmons. (C.) from a number of transparent preparations is decidedly negative upon this point. Where the crura are attached to the primary lamellae, the ribbon is broadened, and just in front of these points there appear to have been two short convergent apophyses which may be construed as discrete elements of a loop. Though an unprecedented occurrence, it would not be surprising or unnatural to find this early gpirigerous shell actually ajugate. Subsequent investigations of the brachidium must be relied upon to determine whether or not the loop was ever a continuous lamella, but hitherto, repeated preparations of the brachial appa- ratus have given no satisfactory evidence of such a structure.* The peculiarities of the internal supports combined with the nature of the hinge-plate and the contour and smooth exterior of the shell, make an associa- tion which removes Alrypa bisulcata from any intimate connexion with Zygos- PiBA, Catazyoa and Glassia, in which the spirals are also introverted, and * Specimens of Atrypa biiulcata in a suitable condition for the determination of the internal characters are rare. When the matrix is opaque, it usually consists of a mass of organic debris which bos brulien down the delicate brachidium. Through the kindness of Mr. W. R Billings, of Ottawa, we have been permitted to examine an extended series of specimens from his collection and to select for cutting such aa poaacoaod a translucent filling, and upon these the determinations have been based. BRACHIOPODA. 149 from Dayia, which, as already suggested, has only an external resemblance to this species. It is not known with certainty whether other representatives of this type of structure exist among the species of the earlier faunas. Mr. E. Billings de- scribed a species, Athyris Lara, from his Division 2 of the Anticosti group,* which has somewhat the form of Cyclospira bisulcata, and Mr. Davidson statesf that it contains introverted spirals. In another species, or series of species, we find abundant and convincing evidence of the existence of a slight modification of this type contemporaneous with Cyclospira bisulcata. The Atrypa exigua, Hall,| a diminutive shell described from the Trenton limestone of New York, has a similar contour to C. bisulcata, though the pedicle-valve is less convex and the ante-lateral margins of the valves bear evidence of coarse plication. In this little shell the brachial valve has a simply divided hinge-plate, and upon these divisions rest the two short convergent crura ; joining the latter at a low angle, the primary lamellae diverge laterally, converge slightly toward their anterior margins, thence curve verti- cally upward, nearly touching the inner surface of the pedicle-valve and very T\a. 137. FIG. 138. The brachidlam of Atrypa {Protoxyga) exigua. Hall. (o.) gradually approaching each other. The ribbon is continued with a decided internal inclination, until it completes slightly more than one entire volution. Toward the anterior margins of the primary lamellae a strong loop is given oflf, its lateral branches projected very obliquely backward, sometimes scarcely rising between the coils, the union forming a broad angle on the anterior mar- gin with a subacute process on the outer margin. In the accompanying figures * Catalogaes of the Silurian Fossils of the Island of Anticosti, p. 47. 1866. t British Silurian Brachiopoda, Suppl., p. 121. 1862. t Paleontology of New York, vol. i, p. 141, pi. xixiii, figs. 6a-d. 1847. 150 PALEONTOLOGY OF NEW YORK. the structure of the brachidium has been represented from silicified specimens. It may be remarked that in some of the preparations of this fossil the loop is situated somewhat nearer the middle of the primary coils. Many preparations have been made of the brachidium in shells of this species not only from New York, but also from the Trenton horizon of Rochester, Minn., Beloit, Wis., and Auburn, Mo. They have been found in various conditions of incrustation and replacement, but with a constancy of the characters described. Atrypa exigua has been playing a somewhat varied role in recent American literature. Sardeson has described it as a new species,* under the name Zygospira? aquila from the Trenton limestone at Minneapolis and other local- ities in Minnesota. Winchell and Schdchert have included it in a supposed primitive impunctate terebratuloid genus, Hallina, and have termed it Hallina Nicolleti.-f Mr. Sakdeson has been the first to give a figure of the internal structure of the shell (op. cit., fig. 18), the specimen represented having been cut in such a manner as to expose only the loop and that portion of primary lamellae lying behind its bases. The appearance of the brachidium is thus quite suggestive of some MAGELLANiA-like brachiopod. This writer, however, recognized the similarity of the brachidium to that of Zygospira, suggesting that in " other sections there appear to be spiral coils anterior to the part shown in the figure, situated in the dorsal valve mainly, and with the apices together." Messrs. Winchell and Schdchert have, from similar incomplete preparations, unfortunately misapprehended the shell. The value of the proposed genus Hallina can not, however, be estab- lished from the characters of this species only, as the type form specified by the authors is Hallina Saffordi, W. and S., from the Trenton or Glade limestone at Lebanon, Tenn. This is a small shell, oval in outline, and with biconvex valves which bear from fifteen to twenty subangular surface plications, begin- ning in the umbonal regions ; it has, therefore, an altogether different exterior from Atrypa exigua, and is indeed not unlike an immature condition of the well known species, common in the Glade limestone and elsewhere at the Trenton * BaU. Minnesota Academy of Natural Sciences, vol. iii, No. 3, p. 835, pi. iv, ti{^. 15-18. 1892. t American Oeologist, vol. iz, p. 292. 1892. Oeological Survey of Minnesota, vol. iii, pp. 471, 474, pi. sxxiv, figs. 59-62. 1893. BRACHIOPODA. 151 horizon, the Atrypa, Zygospira or Anazyga recurvirostra, Hall. The value of the genus Hallina must be derived from this species, and, after examination Fio. 189. Pio. 140. Fig. 141. Preparations showing tlic strnctare of the brachidium In Baltina Saffordi, Winchell and Sohnchcrt. Fig. 139. The pedicle-valTe cat so as to show the tips of the ascending lamellie. T\g. 140. The opposite side, showing the form of the primary lamella as far as the base of the loop, and the char- acter of the latter. Fig. 141. View showing the form of the bracbidiam in profile. (c.) of specimens from the original locality, we have been unable to find evidence that it is any more terebratuloid in its characters than the Hallina Nicolleti ; indeed, it possesses a brachidium of precisely the same structure as the latter.* The Atrypa exigua and Hallina Saffordi present the minimum development of the spiral cones; the inward inclination of their apices, though but slight, and the highly developed loop, show that they are actually inceptive forms of ZyaospiBA, while the difference in external surface of. the two, smooth in the former except for the low folds about the margins, finely and completely plicated in the latter, the nearly vertical plane of the spirals, as well as their brevity, afford again evidence of the great variability in early types of structure. For the Atrypa exigua the term Protozyoa is proposed ; its relations to Cyclospira are evident, the differences between the two lying in the longer, more nearly vertical and parallel spirals of the latter, and (with the present evidence) in its incomplete loop, indications only of jugal processes being present near the posterior part of the primary lamellae, f * BalliTui Saffordi has a simple hinge-plate composed of two discrete processes, upon which the crura are based, a low median septum in the brachial valve, and well defined though small dental plates. For further illustration of this shell, see Supplementary plate. t The internal structure oi Atrypa biaulcata had been demonstrated and described in manuscript under the name Ctclospiba, some time before the treatise on the Silurian Brachiopoda of Minnesota, by Winchbll and ScHDCHBRT (Geological Survey of Minnesota, vol. iii) was undertaken. As it proved desirable to refer to this type of structure in that work, and as the determinations^above given, were known to one of the authors, the name Ctclospiba was there used with our knowledge and consent. ' 152 PALEONTOLOGY OF NEW YORK. Gbnus glass I a, Davidson. 1881. 1849. Atrypa, Sowbrby. Silurian System, pi. viii, fig. 9. 1859. AtMyrUf Saltbr. Siluria, second ed., p. 642, pi. xxii, fig. 16. 1867. Athyris, Davidson. British Silurian Brachiopoda, p. 121, pi. xii, fig. 19; pi. xiii, figs. 5, o. 18SI . Olastia, Davidsok. Geological Magazine, new series, vol. viii. 1882. Olastia, Davidsoh. British Devonian and Silurian Brachiopoda Supplement, p. 38, pi. i, figs. 10-14; pp. 116-120, pi. vii, figs. 9-20. Shells small, biconvex; elongate-ovate in outline; surface smooth. Umbo of the pedicle-valve not conspicuous; beak depressed. Structure of the deltidium and hinge as in Nucleospira. Muscular impression consisting of two widely divergent, oval diductor scars, between which lies a broad ad- ductor scar. i . :i:. Fio. 143. Figs. 142-141. OUu$ta obovata, Sotrerby. Fig. 142. Interior of the pedicle-valve. Figs. 143, 144. Views uf the exterior. Natural size. FIO. 144. (Davidson.) Brachial valve with an internal septum. The spiral cones have their bases toward the lateral margins of the shell and their apices at the center of the internal cavity ; their position with reference to each other is therefore just the reverse of that in Meristella, Retzia, etc. The cones are laterally com- pressed, and the ribbon makes but few volutions. The loop originates as in Atrypa, is continuous, bending downward into the space between the cones and making a sharp angle at the point of union, which may be directed upward. Type, Atrypa obovata, Sowerby. Wenlock and Ludlow formations. In this genus and Cyclospira the spirals are at the extreme of introversion, and the structure of the brachidium in its entirety is quite similar to that BRACHIOPODA. 153 observed in Atrypina, though the introversion of the spirals is less complete in the latter. Glassia stands in the same relation to Atrypina as Protozyga FlO. 145. Brachidiam of Glattia obovata, Sowerby. (Davidson.) to Hallina ; Glassia and Protozyga having essentially smooth exteriors and the others a plicated surface. Other differences will probably be found in Glassia and Atrypina, and these are indicated by the peculiar structure of the deltidial plates in the former, as described above. Davidson recognizes three species of Glassia, G. obovata, Sowerby, G. elongata, Davidson, from the Wen- lock shales, and G. Whidbornii, Davidson, from the middle Devonian of Torquay. The continuation of this type of structure into the Devonian is of interest as being the only instance of the passage of the primitive zygospiroid structure beyond the limits of the Silurian. Glassia is represented in the lower Silurian of North America by an undescribed species found by Dr. C. Romingeb in a drifted boulder of Trenton limestone, near Ann Arbor, Michigan, in association with Cyclospira bisulcata. This species, Glassia Romingeri, has the smooth, con- vex valves and the introverted spirals of G. obovata, but is a more elongate shell. (See Supplement for description.) 154 PALEONTOLOGY OF NEW YORK. Gends ZYGOSPIRA, Hall. 1862. PLATE LV. 1847. Alrypa, OrOiis f, Stmocisvia, Hall. Palaeontology of N.Y., vol. i, pp. 140-142, 288, pi. xv, fig. 15 ( pi. xxxiii, figs. 4, 5 ; pi. Ixxix, fig. 5. 1859. Jthynchonellaf, Hall. Twelfth Rept. N. Y. State Cab. Nat. Hist., p. 66. 1860. Atrypa, Ukhh. Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 69. 1862. Zygotpira, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., p. 164, figs. 1, 2. 1862. Zygotpira, Billinqs. Canadian Naturalist and Geologist, vol. vii, p. 393. 1862. Athyris, Billinos. Palieozoic Fossils, vol. i, p. 147, figs. 125-127. 1863. AUiyris, Rhynchonellat, Billikos. Geology of Canada, p. 168, fig. 152; p. 211, fig. 211 ; p. 212, figs. 214-216. 1864. Stenocixma, Mbbk and Hatobn. Palaeontology of the Upper Missouri, p. 16. 1866. SliyncJionella, Zygospira, Billinqs. Catalogue Silunan Fossils of Anticosti, pp. 44, 46. 1867. Zygospira, Hall. Twentieth Rept. N. Y. State Cab. Nat. Hist., p. 267. 1868. Zygospira, Mbek. Geological Survey of Illinois, vol. iii, p. 377. 1872. Zygospira, Hall. Twenty-third Rept. N. Y. State Cab. Nat. Hist., pi. xiii, figs. 23-25. 1873. Zygospira, Mbbk. Paleontology of Ohio, vol. i, pp. 125, 126, pi. xi, figs. 4, 5. 1875. Zygoxpira, Millkr. Cincinnati Quarterly Journal of Science, vol. ii, pp. 58, 59. 1878. Zygospira, U. P. Jambs. The Palffiontologist, No. i, p. 7. 1879. Zygospira, Ulrich. Journal Cincinnati Soc. Nat. Hist., vol. ii, p. 14, pi. vii, fig. 10. 1882. Zygospira, Hall. Eleventh Rept. State Geologist of Indiana, p. 305, pi. xxvii, fig. 7. 1882. Zygospira, Anazyga, David.son. British Silunan Brachiopoda, Supplement, pp. 122, 128. 1883. Zygospira, Hall. Transactions of the Albany Institute, vol. x, p. 70. 1889. Zygospira, Nettblroth. Kentucky Fossil Shells, p. 138, pi. xxxiv, figs. 21-25. 1893. Zygospira, 'Wijicbell and Schdcbebt. Geological Survey of Minnesota, vol. iii, pp. 465-469, pi. xxxiv, figs. 42-48. Diagnosis. Shells usually small. Outline subcircular or transversely oval. Contour subplano-convex. Surface sharply plicate. Pedicle-valve with a median plicated ridge. Umbo narrow and prominent; beak acute and in- curved. Foramen elongate, rarely apical, enclosed by the deltidial plates. Hinge-line long and straight ; cardinal extremities rounded. A distinct false area is formed by a pair of ridges diverging from the beak toward the cardinal extremities. On the interior the teeth are moderately well developed and unsupported by dental lamellae. The brachial valve is depressed convex in the umbonal region and bears a more or less conspicuous median sinus. The hinge-plate consists of two broad, stout processes, diverging outwardly, grooved on their summits, and separated from each other by a narrow, sharp cleft. They form both the socket walls and crural bases, and are supported by a low median ridge. Muscular impres- sions obscure in the typical species. BRACmOPODA. 155 The crura are short and straight at their union with the primary lamellae, making a rectangular curve. The first half-volution of the ribbon lies just within the margins of the valves, and the number of volutions is small. The spirals have their bases parallel to the lateral slopes of the pedicle-valve and their apices directed obliquely toward the center of the opposite valve. The loop is a continuous band, variable in position and shape. It may originate on the posterior or anterior limb of the primary lamellae, or be placed medially ; its apex is always angular and directed anteriorly and the lateral curves vary in length and degree according to their position with reference to the spirals. Type, Produda modesta, (Say) Hall. Hudson River group. Observations. The existence of atrypiform spirals in Produda modesta (Atrypa modesta, Palaeontology of New York, Vol. I, p. 141), was recorded in the Thir- teenth Annual Report on the State Cabinet of Natural History, p. 69, and subsequently in the Fifteenth Report of that institution ; the structure of the spirals and their connection was described and figured, and the new genus Zyqospira, erected on the basis of these characters. no. iw. FIO. 147. fio. Ustieiisis are from the original localities, and frt)m the investigation of these we ai-e compelled to disagree with Mr. Davidson's determinations given upon pages 126-128 of his Supplement to the British Bi-achiopoda. On page 127 he states that BRACHIOPODA. 159 It ought, perhaps, to be observed that in a postscript note circulated with some copies of the Twelfth Report on the New York State Museum of Natural History, the name ORTHONOMiEA was proposed as a generic designation for Orthis ? erratica. Should it become desirable to distinguish these finely striated species from the more typical coarsely plicated Zygospiba and the biconvex Catazyoa, this term would be entitled to consideration. Genus CLINTONELLA. gen. nov. PLATE LU. Diagnosis. Shells usually small, suboval in outline; valves subequally biconvex, the axis of greatest convexity being oblique, making an angle of about 55° with the vertical axis of the shell. Pedicle-valve with a small umbo, which is compressed laterally, the apex being slightly incurved. The cardinal area is replaced by a wide triangular delthyrium, which is unaccom- panied by any trace of deltidial plates. The medially elevated umbo merges anteriorly into a sinus which makes a deep flexure at the margin ; it bears two plications, both of which reach the beak ; sometimes a trace of a third plication may be seen. The lateral slopes bear from four to eight radial plications of smaller size. On the interior the teeth are prominent, strongly recurved at their tips and supported by lamellae which terminate abruptly. The lower and inner mar- gins of these lamellas are thickened, contracting the pedicle cavity, which is, consequently, narrow and deep. The diductor scars are of moderate size, flabellate in outline and deeply impressed at their posterior extremity. They ATiticostiengU and boretUU "»i-e only variations in shape of the same species, but specifically distinct from the Zygospira (Athyris f) Beadi of Billikob." Further, in indicating the differences between A. Headi and A. A7Uieostleiuiiji, he says : " the most marked extei'nal charactei'S consist in Headih&viug in the dorsal valve a somewhat deep longitudinal depression or sinus, while, on the contraiy, Anticostiensis has the sinus on the vential valve." On the preceding page, in treating of Z. erratica, the author says : " Z. erratica also bears some resemblance to Z. Hendi in its external form, especially as in both species there is a somewhat deep sinus in the doi-sal valve." It seems probable from these statements that Mr. Davidson has confounded the typical A. Beadi with the variety A. Anticostiensis, and this supposition is apparently boi-ne out by the assertion that the Rev. Mr. Glass succeeded in developing the brachial apparatus in Z. erratica. This species, as far as we know, is invariably presei-ved as sandstone casts or in a matrix of sandstone, and to develop its internal apparatus has proven an impossibility. The specimens of Z. Anticostiensis are, how- ever, usually in limestone, and are vei-y favorable subjects for such treatment. 160 PALEONTOLOGY OF NEW YORK. are crossed by traces of the radial surface plications. Between them lie the narrow obovate adductor scars. In the brachial valve the beak is inconspicuous; the umbonal region de- pressed for about one-third the length of the shell, thence anteriorly becoming developed into a median fold. The greatest convexity of the valve is attained in front of the center. The cardinal margin is scarcely thickened ; the dental sockets quite narrow. The hinge-plate consists of two flattened processes, in- clined toward each other and closely approximate along their inner bases, though not meeting. Each process is divided into an anterior and posterior lobe, the latter being the smaller and resting upon the former. These an- terior lobes are narrow and slender, and constitute the crural bases. Spirals are present, but their direction and the nature of the loop are undetermined. A stout median ridge supports the hinge-plate and divides the scars of the adductor muscles. In both valves the lateral portions of the umbonal region is pitted. The plications of the surface are covered by fine, sharp and ele- vated concentric striae. Shell substance, fibrous, impunctate. Type, Clintonella vagabunda, sp. nov. Clinton group. Observations. This interesting shell possesses a hinge-plate of similar struc- ture to that prevailing among the spire-bearing genera of the Clinton fauna, Whitfieldella {W. intermedia, W. naviformis), Hyattella {H. congesta, H. junia), CoELOSPiRA (C planoconvexa), and occurring also in the genus Zygospira. Though the structure of its brachial supports is unknown, the association of the hinge-plate and the peculiar muscular impressions, with the strongly plicated rhynchonelloid exterior, would effect an incongruity if introduced into any of the generic divisions now recognized. The evidence now attainable indicates an intimate relation to Zygospiea, and from these indications it seems probable that this shell will be found to possess introverted spirals. Clintonella vagabunda was obtained from a drifted and decomposed block ol sandstone found without label among the collections presented to the New York State Museum by the Albany Institute. This specimen had been collected by the late Governor De Witt Clinton, in remembrance of whose intelligent, BRACHIOPODA. ' 161 cordial and influential interest in the study of the fossils of the State of New York this generic name is proposed. This small block was virtually com- posed of the shells of this fossil with a few specimens of an undescribed Atrypina {A. Clintoni, sp. nov.) and fragments of the trilobite Encrimrus ornatus. It was probably derived from the outcrops of the sandstone of the Clinton group in Orleans county, or vicinity, New York. Genus ATRYPINA, gen. nov. PLATE Llir. 1845. Terebratula, db Vkrneoil. Geol. de la. Russ. d'Europe et ;de8 Mont, de I'Oaral, p. 96, pi. x, figs. 14 a-e. 1848. Tereibratula, Davidson. Bull. 8oc. Geol. de France, vol. v, second ser., p. 332. pi. ill, fig. 32. 1862. Atrypa, Hall. Palzeontology of New York, vol. ii, p. 277, pi. Ivii, figs. 6 a-7». 18.57. Leptoccdia, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 108. 1859. Leptocmlia, Hall. Palseontology of New York, vol. iii, p. 246, pi. xxxviii, figs. 8-12. 1859. Shynchonella, Retzia, Salter. Murchison's Siluria, second ed., p. 2.50, fig. 6 ; p. 544. 1860. Retzia, Limdstrom. Gotland's Brachiopoda, p. 337. 1867. Retzia f Davidson. Bi-it. Siluiian Brachiopoda, p. 128, pi. xiii, figs. 10-13. 1868. TVematogpira f Mkbk and Worthbn. Geol. Surv. Illinois, vol. iii, p. 381, pi. vii, fig 2. 1879. Corfospira, Hall. Twenty-eighth Ann. Rept. N. Y. State Mas. Nat. Hist., p. 162,'pl. xxv, figs. 39-43. 1882. Calotpira, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 303, pi. xxv, figs. 39-43. 1882. Atrypa, Davidson. Brit. Silur. Brach., Snppl. p. 114, p. vii, figs. 7 a, b. 1889. Ccdospira, Bkbchbb and Clarkb. Mem. N. Y. State Mas., vol. 1, No. 1, p. 64, pi. v.figs. 17-23. Diagnosis. Shells small, subovate or subcircular in marginal outline, piano-, or subconcavo-convex in contour; surface coarsely and sparsely plicated. Pedicle-valve with the umbo prominent, the beak abruptly acute and more or less incurved. Foramen apical, and deltidial plates normally developed. The cardinal margins of the valve are somewhat extended in the typical species, though the hinge itself is quite short. Teeth divergent and unsup- ported, taking their origin on the lateral cardinal slopes, and very slightly recurved. Muscular scars exceedingly faint; no internal septa observ- able. Brachial valve with the cardinal process small, consisting of two short lobes, which meet at their apices, not extending back of the hinge-line, and diverging anteriorly. The surface of each lobe may be longitudinally 162 PALEONTOLOGY OF NEW YORK. Fig. 152. The brnchiOiain otAtrypina disparUi»,liM. (c.) grooved, but the inner and outer divisions thus formed, are confluent at their outer extremities. The anterior face of the process is abrupt and vertical, its lower portion being continuous with the socket walls. In front of the cardinal process, but not supporting it, is a low median ridge, on either side of which are obscure muscular imprints. The brachial apparatus consists of introverted spirals whose bases lie against the lateral slopes of the pedicle-valve and whose apices are directed toward the center of the brachial valve. The ribbon is loosely coiled and makes but three or four volutions. The loop is situated posteriorly and constructed as in Atrypa, except that its lateral lamellae appear to be always united in an acute angle, which is directed inward. Muscular impression composed of large flabellate diductors, enclosing distinct adductor scars. Type, Leptocalia imbricate, Hall. Lower Helderberg group. Observations. It has become necessary to establish a division for a number of little species whose structural characters have not heretofore been well known and which have, on that account, been referred indifferently to various genera, as Ateypa, Leptoccelia, Ccelospira, Trematospira, etc. Among these which are evidently congeneric on the basis described, are Atrypa {Calospira) disparilis, Hall, of the Niagara group, Atrypina Clintoni, sp. nov., of the Clinton fauna, Leptocalia imbricata, Hall, of the Lower Helderberg group, and Atrypa Barrandii, Davidson, of the Wenlock limestone. This type of external and internal structure is continued upward into the lower Devonian where it is represented by the Terebratula sublepida, de Verneuil.* While atrypoid in external expression the shells differ from Atrypa, even in its broadest significance, in their uniformly small size, preponderating convexity of the pedicle-valve, few and very coarse plications usually crossed by fine • Preparations made from specimena of this species from the lower Devonian of the Northei-n Urals, kindly furnished by Pi-of. F. Schmidt, of St. PeteiBburg, show all the internal characters of Atrypina imbricata. BRACHIOPODA. 163 imbricating concentric lines. The structure of the cardinal process differs in some respects from that of Atrypa reticularis, being much more like that of Zygospira modesta ; while, in regard to the brachial apparatus, the coiling of the spirals is lax, the cones themselves introverted more as in Zygospira than in Atrypa, and the loop, though posterior in position, is apparently con- tinuous and acutely angled as in Catazyga. To this group may be applied the foregoing term, Atrypina, a name suggest- ing the affinities of the fossils. Genus ATRYPA, Dalman. 1828. PLATE LIV. 1767. ATiomia, Lis»e. Systema Natui-se, ed. xii, p. 1152. 1820. Terebratulites, Schlotheim. Petrefactenkunde, p. 262, Nachtr., pi. xvii, fig. 2 ; pi. xviii, fig. 2 ; pi. XX, fig. 4. 1821. Anomites, Wahlenbbro. Nov. Act. Reg. Soc. Scienlif. Upsal., vol. viii, p. 65. 1822. Terebratula, Sowkrbt. Mineral Conchology, vol. iv, p. 324, fig. 2. 1828. Atrypa, Terebratula, Dalman. Kongl. Vetenskaps. Akad. Handliiigar, pp. 127, 128, 143, pi. iv, figs. 2, 3 ; pi. vi, fig. 6. 1837. Atryya, Terebratula, Hisingbb. Lethsa Suecica, pp. 75, 81, pi. xxi, figs. 11 a-e; pi. xxiii, figs. 8 a-e. 1842. Atrypa, Co.nrad. Jour. Acad. Nat. Sci. Philadelphia, vol. viii, p. 265. 1842. Atrypa, Hlpparionyx, Vamuxbm. Geology of N. Y.; Rept. Third Dist., p. 88, fig. 12; p. 132, fig. 2 ; p. 139, fig. 5 ; p. 163, fig. 3; pp. 164, 182, fig. 4. 1843. TenbratxUa^ Castelnac. Essai sur le Sysl^me Siluiien, p. 40, pi. xiii, fig. 8. 1843. Atrypa, Hall. Geology of N. Y.; Rept. Fourth Dist., p. 73, fig. 8 ; p. 108, fig. 37 ; p. 175, fig. 5; p. 198, fig. 4 J p. 200, figs. 1, 2; p. 215, fig. 3; p. 271, figs. 1-3; Tab. of Org. Rem., No. 13, fig. 1. 1844. Atrypa, Owbk. Geol. Expl. of Iowa, Wisconsin and Illinois, pi. xii, figs. 2, 10. 1847. Spirigerina, b'Obbiost. Comptes rendus, vol. xxv, p. 268. 1847. Terebratula, Yamdbll and Shomabd. Contnbution to the Geol. of Kentucky, p. 10. 1849. Terebratula, Hall. American Jounial of Science, vol. xx, p. 227. 1862. Atrypa, Hall. Palieontology of N. Y., vol. ii, pp. 72, 79, 270-272, pi. xx, fig. 10 ; pi. xxiii, fig. 8; pi. Iv, fig. 5 J pi. Ivi, figs. 1, 2. 1852. Rhynchonella, Saltkb. Suthei-land's Jour, of a Voyage in Baffin's Bay, etc., vol. ii, p. 221, pi. v, figs. 1-3, 5. 1854. Atrypa, Davidsok. Introd. Britiph Fossil Brachiopoda, p. 90, pi. vii, figs. 87-94. 1866. Atrypa, Billihgs. Canadian Nat. Geol., vol. i, pp. 134, 137, 474, pi. ii, fig. 10 ; pi. vii, fig. 11. 1857. Atrypa, Hkhh. Tenth Rept. N. Y. State Cab. Nat. Hist., p. 122, figs. 1-7; p. 168. 1868. Atrypa, Rogbbs. Geology of Pennsylvania, vol. ii, part ii, p. 828, fig. 671 ; p. 829, fig. 681. 1868. Atrypa, Hall. Geol. of Iowa, vol. i, part ii, p. 515, pi. vi. fig. 3. 1859. Atrypa, Hall. PaliEOntology of N. Y., vol. iii, p. 253, pi. xlii, fig. 1. 1860. Atrypa, Hall. Thii-teenth Rept. N. Y. State Cab. Nat. Hist., p. 84. 1860. Atrypa, Rokmbr. Die Silurische Fauna der westlichen Tennessee, p. 69, pi. v, figs. 9, 10. 1860. Trematospira, McChbsnby. New Palaeozoic Fossils, p. 71. 1861. Atrypa, Billihqb. Canadian Journal, vol. vi, p. 264, figs. 84-87. 164 PALEONTOLOGY OF NEW YORK. 1868. AtryfXh Biu-mos. Geology of Canada, p. 316, fig. 321 ; p. 318. fig. 335 ; p. 384, fig. 416. 1866. Atrypa, Davidsom. British Devonian Brachiopoda, pp. 53-59, pi. x, figs. 3-13 ; pi. xi, tigs. 1-12. 1866. Atrypa, Shalrb. Bull. Mus. Comparative Zoology, No. 4, p. 68. 1867. ./Itrypo, Davidson, British Silurian Brachiopoda, pp. 130-136, pi. xiv, figs. 1-22; pi. xv, figs. 1-8. 1867. Atrypa, Whitfield. Twentieth Rept. N. Y. State Cab. Nat. Hist., p. 141. 1867. Atrypa, Hall. Palseontology of N. T., vol. iv, pp. 312-327, plates li, lii, figs. 1-12 ; pis. liii, liiiA. 1868. Atrypa, Mhkk and Worthbn. Geol. Survey of Illinois, vol. iii, p. 430, pi. xiii, fig. 7. 1868. Dranatogpira, McChbskby. Ti-ans. Chicago Acad. Sci., vol. i, p. 32, pi. vii, fig. 3. 1868. Atrypa, Mkbk. Trans. Chicago Acad. Sci., vol. i, pp. 96, 97, pi. xiii, figs. 12, 13. 1868. Atrypa, Hbbk and Worthbn. Geol Survey of Illinois, vol. iii, p. 432, pi. xiii, fig. 11. 1872. Atrypa, Hall and Whitfikld. Twenty-fourth Rept. N. Y. State Mus. Nat. Hist., pp. 197-199. 1875. Atrypa, Hall and Whitfibld. Palseontology of Ohio, vol. ii, p. 133, pi. vii, figs. 12-14. 1877. Atrypa, Mkbk. King's U. S. Geol. Expl. Fortieth Parallel, vol. iv, p. 38, pi. i, fig. 7; pi. iii, fig. 6. 1878. Atrypa, Ethbridgb. Quart. Jour. Geol. Society London, vol. xxxiv, p. 596. 1879. Atrypa, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p. 162, pi. xxv, figs. 44-47. 1880. Atrypa, Whitb. Second Ann. Rept. Indiana Bureau of Statistics and Geol., p 502, pi. v, figs. 7-9. 1881. Atrypa, Whitb. Tenth Rept. State Geologist of Indiana, p. 134, pi. v, figs. 7-9. 1882. Atrypa, Hall. Eleventh Rept. State Geologist of Indiana, p. 304, pi. xxv, figs. 44-47. 1882. Atrypa, Whitfibld. Geology of Wisconsin, vol iv, p. 333, pi. xxvi, figs. 5-8. 1884. Atrypa, Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 150, pi. xiv, figs. 4, 6. 1885. Atrypa, Fobrbtb. Bull. Denison Univei-sity, vol. i, p. 90, pi. xiii, fig. 9. 1889. Atrypa, Bbbchbr and Clakkk. Memoirs N. Y. State Museum, vol. i, p. 51, pi. iv, figs. 12-20. 1839. Atrypa, Nbttblroth. Kentucky Fossil Shells, pp. 88-92, pi. xiv, figs. 1-23 ; pi. xv, fig. 1 ; pi. xxxii, figs. 5-8, 44-47, 64-66. 1890. Atrypa, Fobrstb. Proc. Boston Society Nat. Hist., vol. xxiv, pp. 314-316, pi. vi, figs. 8, 9. Diagnosis. Shells subcircular or longitudinally suboval in outline. Gibbous, strongly inequivalve. Hinge-line short, straight; cardinal extremities rounded. Beaks not prominent. Pedicle-valve the smaller ; convex in the umbonal region, but depressed and often deeply sinuate anteriorly. Beak small, usually incurved in advanced growth-stages, concealing the foramen and deltidium. The foramen is triangu- lar in young shells, extending to the hinge-line, but becoming gradually closed by the growth of deltidial plates, and at maturity is circular and apical, en- croaching slightly on the substance of the valve. The plates of the deltidium are not coalesced along the median suture. On the interior the umbonal cavity is short but very broad. The teeth are large, widely separated and doubly grooved, first by an oblique furrow at the base, into which is fitted a crenulated ridge of the other valve, then by a short longitudinal depression on the summit ; the tooth is doubly curved and reflected, making the articulation of the valves very firm. These teeth arise from the inner surface of the lateral slopes of the BRACHIOPODA. 165 valve, and are hence unsupported by lamellae. The muscular impressions are sharply defined ; the triangular pedicle-scar is followed in front, by a median elongate double scar of the adductors, outside of which are strong, radiately striate, flabellate diductors, which frequently extend beyond the middle of the valve. Brachial valve convex or rotund in the middle, with a median fold which is rarely developed except toward the anterior margin. Beak incurved and con- cealed. No cardinal area. The hinge-plate is composed of two diverging pro- cesses which may or may not meet at the apex. Each of these processes is obliquely grooved, forming an inner and outer lobe. The latter forms the upper portion of the socket wall which is curved downward and unites with the lateral surface of the valve, forming a broad dental socket which is trav- ersed by an oblique crenulated ridge. The inner lobes of the hinge-plate are short, their extremities free, bearing the crura.* These crura are long and narrow, diverge laterally and are attached to the primary lamellae near their ante-lateral curvature. The mode of attachment FlO. 153. X>\Kgnm ot Atrypa reHeularit i showing the rorm and stmctare of the loop and the mode of attachment of the enira to the hinge-plate anil the primary iameiiie. (C.) is peculiar, the crural lamellae bending upward and then abruptly downward, greatly widening at the line of contact and touching the spiral ribbon only at its outer margin. The deniarkation between the crura and the ribbon of the coils is therefore very distinct. The spirals have, in a general sense, their ba.ses p.arallel to the inner surface of the pedicle-valve and the apices directed toward the deepest point of the opposite valve. Their axes are more or less * In the mode of attachment of the crura, as heretofore i-epi-esented, they have been made to appeal' as if derived from the outer lobes of the hinge-plate. See Palaeontology of New York, vol. iv, pi, liiiA, figs. 22, 29. 166 PALEONTOLOGY OF NEW YORK. convergent, so that the approximate surfaces of the cones are flattened. The basal section of these cones is hemicordate, the anterior extremity being much the narrower, but the upper volutions are more nearly elliptical. The ribbon is broad, being conspicuously so on the anterior curves of the first few volu- tions, each one extending considerably beyond the next following. These anterior curves may be more or less distinctly fimbriated. The loop is com- posed of two processes which are continuations of the primary lamellae without angulation. These processes are situated posteriorly, directed toward the center of the shell, and are, in effect, the starting points of the spirals. They have the following structure : the ribbon maintains its usual width for a consider- able distance within the point of attachment to the crura, then narrows rather abrubtly, the processes ascending as they approach each other. Their termina- tions in mature shells are broadened, thickened, erect and recurved at the tips, having a clavate appearance. In immature growth-stages or undeveloped adult conditions this thickening is absent, the extremities of the processes are in close apposition, or may form a continuous lamella. The muscular impressions consist of four large adductor scars divided by a low median ridge. Ovarian pittings and vascular sinuses occur over the inner surfaces of both valves. The latter consist of two main trunks, sending two branches poste- riorly, and two longer, converging branches anteriorly. External surface covered with radial plications crossed by concentric growth- lines ; at the crossing of the two series of lines the external layers of the shell may be produced into broad lamellar expansions or hollow spines. Shell-substance fibrous, impunctate. Type, Anomia reticularis, Linn6. From the Clinton to the Waverly groups inclusive. Observations. A great number of brachiopods, whose generic relations were of the most uncertain character, have, in the past, been referred to this genus since the date of its establishment. Following closely the foregoing diagnosis will result in eliminating from this group the great majority of species passing under the name of Atrtpa, and in BRACHIOPODA. 167 retaining only those which conform to the well-known A. reticularis, primarily in the structure of the brachidium, and secondarily, in the expression of the exterior. Such forms are comparatively few in number, and most authors have been disposed to regard them as representing unessential variations from the specific type of A. reticularis. There is, however, a multitude of designations which have been applied to contemporaneous variations or consecutive muta- tions of this specific type, some of them unnecessary, but many very useful both to the geologist and the systematist.* Atrypa reticularis is a shell characterized by its fine plications, which duplicate rapidly at or between the concentric growth-lines. This duplication or bifur- cation of the plications occurs at irregular intervals in the growth of the shell. It is a secondary condition of growth and if it manifests itself at an early stage, a finer plication results than when its appearance is delayed until later growth. This variability in appearance and rapidity of recurrence produces individual differences of expression in the plication of the shell, which, however, lead to no varietal modifications. The concentric growth-lines are bases of free squamae or lamellae, which under favorable conditions may be retained, but are usually abraded, so that the com- mon expression of the exterior is that of an entire absence of such growths. This is the condition where the valves have been replaced by silica (a very common mode of retention), or in specimens which have been gathered from compact limestone. Under better preservation, as in soft shales or shaly lime- * The time-valnes of oscillations of, or fi-om the specific type, manifest themselves so clearly in this genus, that it is hei-e necessary to express such vainations with caution and pi-ecision. Bahrande introduced a dis- tinction between pi-imary and secondary modifications of a specific type, by proposing- to restrict the term ixtritty lo the former, thjit is, "to forms which possess the principal charactei-s of an admitted specie?, but which differ from it in one or more important modifications, manifesting themselves in a considerable number of individual.^ ; " ami to designate as variants, secondary modifications of form and surface ornamentation. It would Ijegi-anted by most investi^ratoi-s that modifications of a specific type more essential than changes in foi-m and surface characters, would be a sufficient basis for a complete separation from such species ; hence this distinction between varUiy and varia7it, holding the latter subordinate to the former, becomes largely arVntrary ; and it is only in rare instances that any practical use can be made of it. Variant becomes a useful term applied to the different phases of expression within the limit of the specific type, but in this meaning it is neither subordinate to the term variety, nor does it necessai-ily indicate an inceptive condition in the departui-e of a variety from the specific type. The time- value of variations from the species has been ex|>re88ed by Waaobk, who proposed to resti-ict the teim variety to oscillations of the type contemjioraneous with the type itself, and applied the tei-m mutation to variations appearing after the extinction of the type. 168 PALjEONTOLOGY OF NEW YORK. stones, the shells show the fact that the squamae of earlier growth, or those upon the umbonal and median surfaces of the valves, have been worn off during the life, or before the fossilization of the shell ; the later squamae, which are stronger, broader, and more closely crowded about the margins, are those usually retained, and these are sometimes of great width, not infrequently equaling and sometimes exceeding the diameter of the valves.* This form first appears in the Clinton group of the State of New York, and in rocks of corresponding age elsewhere in the United States. It continues its existence through the Niagara group, the Lower and Upper Helderberg groups, the Hamilton and Chemung groups, and into the fauna of the Lower Carbonif- erous, carrying the same features through all these periods, and presenting no variety of form or surface-markings which can be considered as more than variations of expression depending upon the surrounding physical conditions or similar intluences. Nevertheless, in most of these successive faunas this type- form has, for each one, an expression so distinct and peculiar that these varia- tions, without accessory evidence, are often sufficient for the determination of geological horizons. The shells occurring in the Clinton group of New York and Ontario are characterized by their suborbicular form and the generally small size of the adult, t In the fauna of the Niagara group this form is continued, though its habit of growth is larger, and the concentric lamellae of the surface more closely set, as it prevails in the Niagara shales of New York. In the soft shales and limestone at Waldron, Indiana, it presents itself with greater rotundity or con- vexity of valves ; at Louisville, Kentucky, a common form is a small, elongate rather than orbicular, shell, with characteristically obsolescent plication. Shells of the same character as the last also occur sparingly at Waldron and in New York. In the Lower Helderberg fauna the elongate variant prevails in the Shaly limestone, attaining a greater size than in the preceding fauna; while in * See Davidson, Silurian Brachiopoiia, pi. xiv, figs. 1, 2. Barrahdk, Sj'stJine Silunen, vol. v, pi. xix, fig. 7. Whitkavks, Contrib. to Canadian Palieontology, vol. 1, pi. xxxvii, fig. 8. t It is hanlly necessary, were it possible, to determine with precision which of the many expressions of Atrypa reticularis was borne by the specimens which served the Swedish savant as the type of the species. BRACHIOPODA. 169 the upper and lower Pentamerus limestones the shell is rotund and the elongate form not represented. The absence of the specific type from the Oriskanj fauna has yet to be accounted for. The normal Oriskany fauna of eastern New York is local, and the immigration of this species was probably excluded by the coarse, sandy character of the sediments, and their accompanying physical conditions. Where the fauna of the Oriskany is commingled with that of the Upper Helderberg, as in the arenaceous limestones of the Province of Ontario, Atrypa reticularis reappears with its Devonian aspect. In the Schoharie grit the expression of this shell is rendered peculiar by a flattening or sharp definition of the usually undefined fold upon the gibbous brachial valve. This peculiarity of the brachial valve is lost in the succeed- ing fauna (Corniferous limestone). Here we meet two distinct variants ; (a) a small, elongate shell, like that common in the Lower Helderberg fauna, but invariably of less size (the A. ellipsuidea, Nettelroth) ; these are locally found in great numbers, indicating a gregarious habit ; (b) a much larger, highly convex shell, having an outline intermediate between the others, and without the highly developed sinus of the pedicle-valve. This shell abounds throughout New York, though its occurrences are mostly in scattered or isolated areas. Passing to the Hamilton fauna, the prevailing forms are of medium size, with straight, somewhat extended cardinal line, moderately gibbous brachial valve and highly lamellose surface about the margins. These are accompanied rather sparingly by shells of great size, which do not, however, materially modify their external expression. In the calcareous beds of the upper Devonian, as in Iowa, these large shells become predominant, retaining the outline of their predeces- sors in the Hamilton group, but farther characterized by the lateral compression of the brachial valve. The smaller form, which occurs sparingly in the Che- mung sandstones of New York, is still similar to that prevailing in the Hamilton shales. The figures given by Professor Herrick,* of the shell occurring in a Devonian facies of the Waverly, or earliest Carboniferous fauna of Ohio, indi- ♦ Herrick, Bulletin Scientific Laboratories of Denison Univereity, vol. iii, p. 98, pi. iii, fig. 11, 1887 ; vol. iv, pi. ix, fijf. 7, 1888 The expression of this Waverly shell, judging from the figures cited, is more that of the mediom sized individuals of the Hamilton group than of the large forms of the later Devonian. 170 PALEONTOLOGY OF NEW YORK. cate that the species at its latest appearance had undergone no variation in form or surface-characters. The range through time, of Atnjpa reticularis, is unequaled by any other organism except that of the brachiopod Leptana rhom- hoidalis, Wilckens, and it far outranks that species in geographic distribution and prolific individual development. Almost coincident in time with the appearance of Atrypa reticularis, in its typical aspect, we find in the shales of the Niagara group shells which are per- sistently small, with few and coarse plications, more or less distinct median fold and sinus, and strong concentric lamellaB. These shells have been desig- nated as Atrypa rugosa and A. nodostriata, Hall. The former is the smaller and more extreme in the simplicity of its exterior. During the periods of the Lower Helderberg and Oriskany in New York, and throughout the known extent of these faunas, such coarsely plicated shells entirely disappeared from view, but returned in a depauperated condition in the Corniferous limestone. In the Hamilton group they acquire a much larger size and very gibbous form, the concentric lamellae being distant and strongly developed. This is the shell known as Atrypa aspera, Schlotheim. At this horizon the form mentioned is intimately associated with the typical, more finely plicated A. reticularis, but abundant material affords no evidence of the passage from one to the other. The coarsely plicated shell is continued into the Chemung group, where, in New York, it presents a peculiar expression in the much reduced number of its plications, and in the strong median elevation of the brachial valve, which is not infrequently concave in the middle and angular on the margins, these angulations becoming nodose from the elevation of the strong concentric lamellae. In the calcareous sediments of the Chemung group in the State of Iowa and other northwestern localities, the coarse-ribbed shells also abound, though they possess a different expression than those of the eastern Chemung fauna, having a very gibbous brachial valve without median fold, and more conspicuous plications. They do not, however, approach even remotely, the appearance of the typical A. reticularis, with which they are associated. These shells have been designated by the term A. aspera, var. occi- dentalis. Hall. BRACHIOPODA. 171 There are certain coarse-ribbed variations of the typical A. reticularis occur- ring in the Upper Silurian faunas of Great Britain, Sweden and Bohemia, which appear to be unrepresented in North America. These have sometimes received the designations of var. aspera or Murchisoniana, but writers who have dealt with them agree that they are connected by insensible gradations with the typical form of the species. These seem to us to be simply instances of individual variation due to a deficiency in the usual bifurcation of the plica- tions, and leading to no such distinct specific expression as that borne by Atrypa rugosa, of the Niagara group. Yet to fully apprehend the fundamental relations of the species Atrypa reticularis to the species A. rugosa, it is necessary to have recourse to extremely young conditions of the species. Figure 1, on Plate LIV, represents the earliest growth-stage of A. reticularis observed, the shell having a length of 2.2') mm. This is still a secondary condition of growth, as shown by the two concentric varices and the well-developed plica- tions, but the simplicity of the latter and their relatively great size is a char- acter continued to much later growth (see, for example figs. 21, 22, on plate xiv, of Davidson's Silurian Brachiopoda). When duplication begins, it is carried on with great rapidity in the development of the typical form. It is thus evident that coarse and sparsely duplicated ribs accompanying normal adult size imply a continuance of immature conditions, or an early deficiency of development ; and this genetic modification is the more forcibly expressed when the size of the adult is small, as in A. rugosa.* However strong the presumptive evidence may be, that the typical or finely plicated Atrypa reticularis, and the coarse-ribbed forms known as A. rugosa, A. aspera, etc., have originated from a common source, we can not yet indicate the form to which they are both united by an uninterrupted transition. At all events, from the opening of the Upper Silurian to the close of the Devonian period, the two types of external structure have led an independent existence. Though in American faunas, the line of descent of A. reticularis is interrupted • The simple exterior of this fossil suggests its relation to the still smallei-, coai'sely plicated shells which have been placed under the genus Atrtpina {A. disparilis, Niagara group ; A. imbricata, Lower Helder- berg group). In the structure of its brachidiuni and the direction of the spiral cones, A. rugosa is a true Atbtpa, although its loop is continuous. 172 PALEONTOLOGY OF NEW YORK. during the epoch of the Oriskany sandstone, and that of the coarse-ribbed type broken by an hiatus extending from the close of the Niagara to the opening of Corniferous epoch, this is a purely local or American peculiarity. There is abundant evidence in the works of European writers, of the presence of both forms in faunas of Russia and Germany which are essentially homotaxic with the Lower Helderberg and Oriskany of this country.* In the variant of Atrypa reticularis, occurring in the Niagara fauna at Waldron, Indiana, the free concentric laraellae frequently show a tendency to fold inward at the summit of the principal plications. The infolded edges fail to unite, and this tendency to the formation of tubules is apparently carried no further at this period. More extreme results were attained by the Atrypa aspera of the Hamilton shales, or possibly by its migrated ancestor, dur- ing the period of time represented by the deposition of the Lower Helderberg, Oriskany and Upper Helderberg sediments. At all events, the Atrypa spinosa of the Hamilton shales is but an A. aspera with the lamellae enfolded into tubular spines. Intermediate stages connecting these different phases are not present in this fauna ; it is furthermore evident that these spines are an early genetic condition, being found on the youngest portions of the adult shell ; both of these facts pointing to the attainment of this condition at an earlier period. This spinose form is continued into the Chemung faunas (A. hystrix), with some modification of expression, the spines being few and long, and the plication of the surface very coarse and quite simple ; the shell in its decline thus representing a decided return to the primitive type of structure. Contemporaneously with the form of A. reticularis in American faunas, appears another, the Atrypa marginalis, Dalman, which, according to Salter and Davidson, actually antedates A. reticularis in Great Britain, where it is stated to occur as low down as the Caradoc. ♦ See d'Archiac and db Vbrnbdil. Q6ologie rie la Russie, etc., p. 93, pi. xi, fig. 13. 1846. ScHiTDB. Palsoiitogi-apbica, vol. iii, p. 181, pi. xxiv, &g. 4. 1854. Katskr. Abhandl. Geol. Specialkarte von Pi-eusa. u. den Thiir. Staat., pp. 184, 185, pi. xxviii, figs. 4-6. 1878. TsciiKKHYSCHBW. Fauna des unt. Devon am West-Abhange des Urals, p. 42. 1885. BRACHIOPODA. 173 This shell is characterized by its sharp median fold and sinus, numerous fine fasciculate plications and freedom from concentric lamellae. The expres- sion of the species is thus quite different from that of A. reticularis, but after the introduction of the Wenlock fauna the connection between the two is indicated by the Atrypa imbricata, Sowerby, which is a similar but highly im- bricated shell, whose resemblance to Atrypa rugosa of the Niagara group at once suggests itself. The type of A. marginalis was not highly variable nor, in America, long-lived. A small variety is the A. Calvini, Nettelroth, of the Niagara formation at Louisville. After the disappearance of the Niagara fauna, however, this group does not return, unless the imperfectly known A. pseudomarginalis,'RTi\\, oi the Upper Helderberg group, be considered a remote descendant. All the forms considered above are true Atrypas in the structure of the brachidium, so far as that feature is known. No successful attempt has been made to demonstrate this structure in the Lower Silurian representatives of A. marginalis, but should they prove to possess slightly convergent spiral cones, directed toward the middle point of the brachial valve, and a simple continuous loop, as iu later examples of the species, and most of the early forms of A. reticularis, we may seek the source of Atrypa in early Silurian times. It seems not to have been a derivative of Zygospira or Catazyga, but to have developed in a line essentially parallel with those genera and to have had its origin in common with thera. The variations in exterior form are accompanied by some degree of differ- ence in the structure of the brachial supports. How far this apparent difference is due to the stage of development of the individual has yet to be determined. The normal form of the spirals in the mature A. reti- cularis, is that of laterally compressed cones, the first two or three coils of the ribbon being extended beyond the rest along their anterior cur- vature. In A nodostriata the mature form of the spiral is a cone, which narrows quite rapidly above its base, is round and slender, tapering to an acute apex which is inclined inward to meet that of its companion ; while in 174 PALEONTOLOGY OF NEW YORK. A. marginalis* the cone is broad, obtuse at the apex and the anterior curves of the ribbon are not materially extended. In young individuals the cones appear to be broad, low and obtuse, and the ribbon makes but few volutions. The form and structure of the brachidium was represented in a series of beautiful figures, by Mr. R. P. Whitfield, in 1868,f and some of these were reproduced in the Fourth Volume of the Palaeontology of New York. The peculiar structure of the loop as a pair of separate pro- cesses, was first accurately figured by Qdenstedt,J and afterwards described and illustrated by Mr. William Gdrley. § The character of these lamellae has been given in the diagnosis of the genus, but it is highly probable that these lateral processes of the loop were not discrete in all stages of growth. Mature specimens frequently have the extremities of the process in so close apposition that to all appearances they are united ; young individuals rarely show any trace of disunion at the center of the loop and often no evidence of unusual thickening at this point. Mr. Davidson, who has called attention to the interrupted loop in A. reticularis, also figured in the same work II a preparation of A. marginalis in which the loop is continuous. A specimen of A. marginalis in which the lateral processes of the loop are distinct is figured on Plate LIV, fig. 24. After examination of a considerable number of preparations of the loop made from immature specimens, it seems highly probable that this process was disrupted as the age of the individual and the strain upon the loop from the rapid growth of the spiral coils increased. Should this proposition be sup- ported by more detailed investigation, it will help to an explanation of the uninterrupted condition of the loop in all stages of growth in the atrypoid genera, Zygospira, Glassia, Atrypina, etc. They are forms which virtually antedated the appearance of Atbypa, and the more elementary condition of * Davidson hasBhonn that thespii'al ribbon in this form is fimbriated, and this character wp also find well preserved in natural preparations of the spirals of A. retictt/aris from the Hamilton formation of Clarke county, Indiana. t Twentieth Ann. Kept. N. Y. State Cab. Nat. Hist., pp. 141-144, pi. i, figs. 1-8. 18C7. X Petrefactenkunde Deutschlands, Brachiopoden, pi. xlii, figs. 87a, 90. 1871. $ Proceedings American Philosophical Society, vol. xvii, p. 837, jil. xiv. 1878. I British Silurian Brachiopoda, Suppl. p. 113. 1882. BRACHIOPODA. 175 their structure is indicated, among other things, by their possessing, through- out the existence of the individual, a condition of the loop which was but an immature phase in Atrypa. The mode of attachment of the crura to the primary lamellae has not before been fully described, though the figures given by Whitfield and QuENSTEDT approach the truth most nearly. Among the illustrations of the genus is one (Plate LIV, fig. 17) showing a malformation or hypertrophy of one of the crura, which had become detached from the hinge-plate during the life of the animal. The effort to renew the connection was not success- ful, but resulted in an extravasation of testaceous matter about the broken extremity; such, in fact, as has taken place about the disconnected extremities of the loop. Subgenus GRUENEWALDTIA, Tschernyschew. 1885. PLATE LU. This name has been proposed * for the species Terebratula latilinguis, Schnur,f originally described from the middle Devonian at Gerolstein. This species was Fio. IM. Fig. 166. SpirsU of Omtnevxitdtia latilinguU, Schnur. In llg. 15S, the pedicle valve is the lower and tlie two median dots repraunt sections of llio primary lamella). (Tschebnyschew.) considered by Kayser as a variety of Atrypa reticularis.^ The Russian speci- mens have the pedicle-valve very convex, the relative convexity of the valve in A. reticularis being reversed in this species. From the description and figures given by Tschebnyschew, the spiral cones have their bases lying against * Die Fauna des Unteren Devon am West-abhanjfe des Urals, pp. 46, 89, pi. vi, figs- 78-77. t Ziisanimenslellung and Beschreibung gammtlicher im Uebergangsgebirge der Eifel voi'kommenden Brnchiopoden, p. 183, |>1. xxv, fig 1, 1853. I Zuitscbi-. der deutsch. geol. Gesellsch., vol. xxiii, p. 545. 1871. 176 PALEONTOLOGY OF NEW YORK. the lateral slopes of the pedicle-valve, and thus the outer face of the cones is parallel to, and just within the surface of the brachial valve. It is such a modification of the brachial apparatus as must necessarily ensue from the variation in the contour of the shell. The character of the loop has not been determined. Genus KARPINSKIA, Tschernyschew. 1885. PLATE LII. This designation has been applied* to a species, Karpinskia conjugula, Tscher- nyschew, from the lower Devonian of the Ural Mountains, which is character- ized by an elongate form, radially plicated and subequally convex valves. The spirals have the same position as in Atrtpa, though the character of the loop is still unknown. In the pedicle-valve are diverging dental plates, and in the brachial valve a median septum. The vascular trunks are simple and direct, extending to the anterior margin of the valves without branching. * Die Fauna des Unteren Devon am West-abhangre des Urals, pp. 48, 90, pi. vii, figs. 80, 86. BRACHIOPODA. 177 Genus RHYNCHONELLA, Fischer de Waldheim. 1809. The number of palaeozoic species which are currently referred to this genus, and consequently regarded as congeneric with the Russian upper Jurassic R. loxia, Fischer, the type-species, is very great. To the most conservative student such an assemblage, presenting every variety of external configura- tion, must seem more like a hap-hazard and conventional association than a natural group. But we are, nevertheless, here confronted by the fact that leatures of internal structure, upon the variations of which we are wont to base taxonomy, are most persistent. The crura, hinge apparatus and deltidial structure of R. loxia are features which were attained and became fixed in the Silurian period; the extreme pyramidal contour of that species, its smooth surface with few and faint marginal plications, is not, however, except in rare instances, reproduced among the palaeozoic forms. What is thus true of the predecessors of R. loxia is also, to a large degree at least, true of its living descendants. From a careful study of the structure of the ancient Rhynchonellas it has become apparent that slight variations from the type of interior possessed by R. loxia are frequently of marked continuance, and we must, therefore, be pre- pared for closer discriminations in this great group of species th.an have else- where been necessary or advisable, and to emphasize such of these deviations from this stable line of development, as are justified by their persistence and the convenience of classification. The earlier names introduced among this group of fossils, such as Cyclothyris, McCoy, Hypothyris and Epithyris, Phillips, were based upon the relations of the foramen to the deltidium. It has now become evident that these varying relations are essentially developmental phases. A triangular pedicle-aperture is an immature condition ; it may continue as such even to maturity, or through- out the existence of the individual; it may become closed by normal growth of the deltidial plates, which remain discrete or become united, at first enclos- ing, and perhaps finally obliterating, a subapical foramen; in mature and senile conditions, the aperture if extant, may, by resorption of the shell, encroach 178 PALEONTOLOGY OF NEW YORK. upon the apical substance of the valve. Persistence of any of these conditions at maturity may be of collateral value in determining the subdivisions of these fossils, but it is impossible to base important values upon them. It is indeed uncertain whether the authors of the names above mentioned had before them species of Rhynchonella, and those terms must necessarily be rejected. The first inquiries before us are : What is Rhynchonella in its strict signi- fication ? and, How far is it represented in palaeozoic faunas ? Genus RHYNCHONELLA, sensu stricto. PLATE LVI. * 1809. Rhynchimdla, Fischbr db Waldhbih. Notice des Fossiles du Gouv. de Moacou, p. 35, pi. ii, &gs. 5, 6. 1827. Rhynchonella, db Blainvillb. Diet, des Sciences Naturelles, vol. xtv, p. 426. 1837. RhyiiclioneUa, Fischbr dk Waldheim. Oryctogr. du Gouv. de Moscou, pi. xxiv. 1853. Rhynchonella, Davidsos. Introd. British Fossil Brachiopoda, pi. vii, fig. 99. 1856. Rliynchonella, Sukss. Classif. dei- Bracbiopoden vou Th. Davidson, pi. iv, fig. 1. 1871. iJAj/ncAone/to, QuBNSTEDT. Peli-efactenkunde Deutschlands ; Bracbiopoden, pi. xxxviii, fig. 108. 1880. Rhynchonella, Zittbl. Handb. der Palaontologie, ji. 689, figs. 529 a-d. Subpyramidal shells having the margins of the valves sinuous or angulated. Pedicle-valve with a median sinus beginning in front of the convex umbo, and in the type-species, becoming broad and deep, producing a prominent lingui- form extension at the anterior margin. Brachial valve convex in the umbonal region and developing anteriorly a prominent median fold. Surface of both valves more or less plicated, often accompanied (as in the type) by fine con- centric lines of ornament. The apex of the pedicle-valve is but slightly incurved and exposes a circular or elongate-oval foramen enclosed by deltidial plates beneath, and above by the substance of the valve. There is a narrow pseudo-area defined by oblique cardinal ridges diverging from the beak. On the interior the teeth are well developed and are supported by lamellaB which rest on the bottom of the valve near the beak, but are free anteriorly. The muscular area consists of a moderately deep oval scar extending one-third the length of the valve, and composed of two large diductors completely enclosing * The citationa hei-e given refer only to Rhynchonella loxia. Accounts of congeneric Jurassic species will l>e found in the works of Davioson, Fischkr de Waldhbih, Sowbbbt, d'Arohiao and db Vbrnbdil. BRACHIOPODA. 179 small central adductors. The posterior surface about the muscular area is pit- ted with ovarian markings. In the brachial valve there is no cardinal process; the crural plates are simple divergent, somewhat expanded on the upper surface but not conjoined except where they converge beneath the beak and meet the median septum, which extends for about one-half the length of the valve. The crura are long and curved upward toward the opposite valve. Muscular area elongate-sub- quadrate, with small posterior and large anterior adductor scars. Shell-structure fibrous. Type, RhyncJwnella loxia, Fischer de Waldheim.* Upper Jurassic. Observations. It may be doubted whether precisely this combination of internal characters exists among the palaeozoic faunas. To the expression of so extreme a view we have been led by the fact that of all the preparations, natural and mechanical, of the interior structure of these shells that have been examined, none show a strict conformity therewith, each possessing some variation of considerable significance; a linear or a clavate cardinal process ; absence of dental lamellae or brachial septum ; coalesced crural plates or an inter-crural pit. These differentials permit groupings of the palaeozoic species among themselves, which do not include the typical Rhyn- chonellas. The interior of many of the American palaeozoic species is still unknown ; the foregoing statement is based upon the representatives of the various faunas that we do know, which, indeed, taken together make a major percentage of described species. As to exterior characters, the peculiar modi- fication of form possessed by R. loxia is most rarely met with in palaeozoic species, perhaps only in the R. acuminata, Martin, of the upper Devonian and the Carboniferous, and, naturally enough, this species fails to conform in internal structure with R. loxia. The modifications of external form, while manifestly of subordinate significance, accompany with some persistence the variations of the interior. * This (Uagnosig h«8 been derived from excellent exteriors and internal casts of R. loxia, from Charas- chowa, Russia. 180 PALEONTOLOGY OF NEW YORK. The evidence leaves little room for doubt that the combination of characters forming the rhynchonelloid type of structure deviated at an early age from the same stock whence Orthis has been derived. The earliest " llhynchonel- las " of which we know the interior, are not Rhynchonellas in any true sense, but properly connecting morphological phases between Orthis and Rhyncho- NELLA, inceptive stages of the fuller development attained in later faunas. In this aspect of the subject it seems preferable to consider the palaeozoic Rhynchonellas essentially in a chronological order, thereby leading up to the later types of structure, and thus following the natural course of development and variation so far as the material in hand permits. At the outset it will be necessary to indicate the very primitive structure obtaining in some of the earliest species, and in order to distinguish these in- ceptive forms it will be necessary to introduce, as a new division, the Genus PROTORH YNCH A, gen. nov. PLATE LVI. 1847. Atrypa, Hall. Palffiontology of New York, vol. i, p. 21, pi. iv (bis), fig. 5. 1862. Porambonites, Billings. Palieozoic Fossils, vol. i, p. 140, figs. Ill a-g. Shells biconvex, with a low, ill-defined fold and sinus on brachial and pedicle- valves respectively. Pedicle-valve with a false cardinal area defined by ridges diverging from the beak. Pedicle-passage triangular, rarely showing any trace of deltidial plates. Teeth very small, supported by thin lamellae which rest upon the bottom of the valve and are not adnascent to the lateral walls of the shell. In the brachial valve the dental sockets are small; the hinge-plate con- sists of two minute discrete processes, the surfaces of which are slightly inclined toward each other. These were the bases of the brachial supports but show no points of attachment to the crura ; they are separated by a triangular inci- sion extending to the bottom of the valve. There is no cardinal process nor median septum in the brachial valve, and no trace of muscular scars in either valve. Type, Atrypa dubia. Hall. Chazy limestone.* • It should be observed that these details of structure have been derived from specimens obtained Irom the gorge of the Kentucky river, at High Bridge, Kentucky. BRACHIOPODA. 181 Observations. These characters, it will at once be remarked, are rhyncho- nelloid, but are essentially primitive in all respects. The type of structure, if strictly interpreted, does not appear to have been a prolific one. The associates of Atrypa dubia in the Chazy fauna, namely, A. plena, Hall, and A. altilis, Hall, are larger, more coarsely plicated shells, with a short median sep- tum in the brachial valve, and a stronger development of the crural bases. They evince a higher development of rhynchonelloid characters and perhaps may be regarded with more propriety as early representatives of the large division here termed Camarotcechia, than as congeneric with Protorhyncha dubia. The Poramboniies Ottawamsis, of Billings, from the Black River limestone of the Pauquette Rapids, appears to be a representative of this structure. The relations of Protorhyncha with the genus Orthis are evinced in the tendency to the formation of a cardinal area, the usually open delthyrium at maturity, and in the short, blunt hinge-processes. Genus ORTHORH YN CHUL A, gen. nov. PLATE LVI. 1889. Orthis, Nbttelroth. Kentucky Fossil Shells, p. 41, pi. xxxiv, figs. 7-13. Shells rhynchonelloid in contour ; hinge-line short, straight, extending for about one-third the transverse diameter of the valves. A true cardinal area is present on both valves, that of the pedicle- valve being considerably the broader, erect, often incurved. Each valve also possesses a distinct triangular delthy- rium, that of the pedicle-valve, according to the evidence at hand, never being in any degree closed by deltidial plates. External surface strongly and simply plicated, the median fold and sinus being well developed. On the interior, the pedicle-valve possesses blunt teeth which rest upon the laterally thickened walls of the valve and are not supported by lamellae. Between, and slightly in front of these lies a short, subquadrate muscular scar. The brachial valve possesses a linear cardinal process, on either side of which are two discrete crural plates, sharply concave on the upper surface and diverging anteriorly for a considerable distance. Shell-substance fibrous, impunctate. Type, Orthis Linneyi, Nettelroth. Hudson River group. 182 PALJEONTOLOGY OF NEW YORK. Observations. No more decisive evidence of the close generic relations of Orthis and Khvnchonella than is furnished by this species, can be desired or expected. The shell is, in effect, a Platystrophia with shortened hinge, nar- rowed and acuminate beak, and well-developed crural processes ; or the propo- sition is convertible ; it is a Rhynchonella, with cardinal areas and uncovered delthyria on both valves. There is a singular anachronism in the sole appear- ance of this type of structure at a period so long after the distinctive ingredient stocks were well established, a fact which may, to some degree at least, be ascribed to our incomplete knowledge ; at the same time there is an eminent fitness in the concurrence of this PLAXYSTROPHiA-like Rhynchonella in a fauna with Platystrophia itself, at its highest and most varied development. Orthorhynchula Linneyi is rather widely distributed in the Hudson River fauna of Kentucky, but is not known to the eastward. Genus RHYNCHOTREMA, Hall. 1860. PLATE LVI. 1843. Atrypa, Conrad. Journal Acad. Nat. Sci. Philadelphia, vol. viii, ji. 264. 1847. Atrypa, Hall. Palseontology of N. Y., vol. i, pp. 146-148, 289, pi. xxxiii, figs. 13a-y, 14 a-c; pi. Ixxix, fig. 6. 1859. Rhynchonella, Hall. Twelfth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 66, 66. 1860. Rhyndtotrema, Hall. Thirteenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 66-68, figs. 8-13. 1873. Rhynchonella, Mekk. Palseontology of Ohio, vol. i, p. 123, pi. xi, figs. 6 a-f. 1875. Trematospira, Miller. Cincinnati Quarterly Jounial of Science, vol. ii, p. 60. 1889. Rhynchonella, Nkttblroth. Kentucky Fossil Shells, p. 83, pi. xxxiv, figs. 26-29. This name, introduced more than thirty years ago, was designed to indicate a peculiar variation in structure, which is not often retained even in the type- species itself, though its absence is unquestionably due to accidental causes. On this account, perhaps, the term Rhynchotrema has failed of general adoption, and it is only quite recently that some writers* have indicated a disposition to employ it. *8ee Waaokv, Salt-Range Fossils, p. 410. Dr. Waagen, taking as of prime importance the absence of dental lamellte in the typical species, has suggested the occurrence of the group among the American De- vonian Rbyncbonellas. Probably, however, the type of structure, of which the lack of dental lamella; is but a single element, was more narrowly restricted in its vertical range. CEhlbrt, in Fischer's Manuel de Conchyliologie (1887), has also used the term, and accompanies it with some original figures, used in a pre- vious publication (Bull. Soc. G6ol. de France, 3* Ser., t. xii, p. 426, pi. 10, a, b), but which fail to show the ciitical characters of the genus. BRACmOPODA. 183 In the Thirteenth Annual Report of the New York State Cabinet of Natural History (1860) some specimens of Rhynchmella increbescens* Hall {==R. capax, Conrad), from the Hudson River group of Iron Ridge, Wisconsin, which pre- served the details of internal structure most admirably, were described and illustrated. The essential part of this description (p. 67) was as follows : " This species, like some others of the genus, becomes extremely gibbous or ventricose with age, and the apex of the ventral valve is closely incurved over the beak of the opposite valve. Nor is this all, for the beak is perforate, and in many specimens we are able to discover a distinct foramen in the substance of the shell ; indeed, sometimes this foramen is above or exterior to the apex of the beak, but it is rarely possible to distinguish the continuity of the sub- stance of the shell between this foramen and the beak of the opposite valve. Externally, therefore, this feature might not be considered incompatible with Rhtnchonella, where the base of the foramen is often formed by the beak of the dorsal valve ; and it might be supposed that as the shell increased and the incurvation became too great to permit the protrusion of the pedicle at the ordinary foramen, the notch in the beak might be deepened until it would reach beyond the apex. Sometimes, however, this foramen is seen to be surrounded by the substance of the shell ; thus becoming a simple perforation, without the appearance of deltidial plates. " The real condition and relations of this foramen I have recently been able to determine satisfactorily, from an examination of some separated valves and imperfect specimens collected by Mr. Woolson, of Iron Ridge, Wisconsin, from the green shales beneath the iron ore. The interior of the dorsal valve has the usual aspect of this valve of other Rhynchmella, except that in the center of the apophysary process, at the base of the crura, there is a narrow central process which is more distinct than usual. In the ventral valve there are two strong teeth which fit into deep sockets in the opposite valve and above these, the triangular space is partially or entirely occupied by a concave solid area ; beneath which, extending from the interior of the shell, there is a distinct foramen * It seems necessary to consider as the Bky^ichonella capax of Conrad, the ventncose shells which, in the woi-k cited, were referred to R. increbescens. The latter term was introduced in 1847 for shells fiom the Trenton limestone of New Yorli, which never attain the great giljljosity common in R. capax, but are not unlike the immature individuals of that species. It seems therefore R. increbescens has no higher value than a designation for an earlier and somewhat modified type of R. capax. 184 PALJEONTOLOGY OF NEW YORK. which passes out at the apex or above the apex of the valve, a groove on the lower side always extending thence to the apex. This area [deltidium] some- times shows a longitudinal suture line, but this feature is not always visible." The original specimens from which this account was derived are now before us, and enlarged drawings have been made from them which will show more clearly than did the original wood cuts, the accuracy of the description. The solid process in the umbonal cavity of the pedicle-valve is the deltidial plates, which are of great size, and are cemented firmly to the bottom of the valve. The concavity of their surface must be due, in a large degree, to the obese growth of the valves which forced the apex of the brachial valve against the deltidial wall. In younger shells, therefore, we should expect to find this cavity less strongly developed. Frequently these deltidial plates are wholly detached, and where retained, as in specimens from Richmond, Indiana, and elsewhere, they are narrower, not meeting and enclosing the foramen beneath, as in the shells described above. The encroachment of the pedicle-passage upon the substance of the valve, is thus due somewhat to the individual conditions of the shell, and is analogous to the complete enclosure of this channel in old examples of Lepiana rhomboidalis, Wilckens, to which reference has been pre- viously made. The teeth rest upon the thickened lateral walls of the valve, and there appears to have been no development of dental lamellae unless it was at a very early period in the life of the individual. In the brachial valve there is a thickened median septum which may extend for more than one-half the length of the shell, and it is upon the posterior extremity of this that the slender median cardinal process rests. This delicate apophysis is frequently distorted to one side or the other. The bases support- ing the crura are divided by a very narrow median cleft, and are remarkably broad and stout, abruptly deflected to the deep dental sockets. The crura take their origin from the central portion of this comparatively broad hinge-plate, instead of from the margins of the dental sockets, as is usually the case in the palaeozoic rhynchonelloids. The structure of the hinge apophyses in both valves is a persistent character, while the peculiarities of the deltidium, as has been observed, are variable with age and external conditions. The muscular BRACHIOPODA. 186 impressions are usually strongly developed, there being beneath the deltidial plates a deep scar of the pedicle-muscle, while the adductor impression on the pedicle-valve is often very marked. The adductors of the brachial valve and the diductors of the pedicle-valve are more or less distinctly defined. Shells possessing the features indicated became prevalent in the fauna of the Hudson River group {R. capax, Conrad, R. increbescms. Hall, R. dentata. Hall), but probably made their earliest appearance in that of the Trenton limestone {R. increbescms, Hall, Trematospira quadriplicata, Miller). There is thus far no satisfactory evidence of its existence in later faunas. Genus R H YN CH OTRET A, Hall. 1879. PLATE LVI. 1828. Terefyratula, Dalman. Kong. Vetenskaps-Akad. Handlingar, p. 141, pi. vi, fig. 3. 1828. Terfbratula, Hisingbr. Bidrag till Sveriges Geognosi, pt. iv, p. 239, pi. vi, fig. 3. 1839. Terebratula, J. db C. Sowbrbt. Silurian System, p. 625, pi. xii, fig. 13. 1846. Atrypa, McCoT. Synopsis Silurian Fossils Ireland, p. 39. 1848. Hypothyrig, Phillips and Salter. Mem. Geol. Survey of Great Britain, vol. ii, pt. i, p. 2S0. 1852. Atrypa, Hall. Palseontology of New York, vol. ii, p. 276, pi. Ivii, figs. 4 a-r. 1859. n/iynchoTiella, Hall. Twelfth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 77. 1859. Retiia, Salter. Murchison's Siluria, second edition, pi. xxii, fig. 8. 18C0. Rhynchonella, Limdstrom. Ofvers. Kongl. Vetenskaps-Akad. Forhandl., p. 365. 1867. Rhynchonella, Davidsok. Bi-itish Silurian Brachiopoda, p. 164, pi. xxi, figs. 7-11. 1879. Hhynchotreta, Hall. Twenty-eighth Ann. Rept. N.Y. State Mus. Nat. Hist., pp. 166-168, fig8.1-4, pi. XXV, figs. 29-38. 1882. Rhynchotreta, Hall. Eleventh Ann. Rept. State Geologist of Indiana, pp. 309-311, figs. 1-4, pi. XXV, figs. 29-38. 1883. RJiynvhoTulla, Davidson. British Silurian Brachiopoda, Suppl., p. 154, pi. x, figs. 9, 10. 1889. Rhynchotreta, Bbbcubr and Clabkb. Mem. N. Y. State Mus., vol. i. No. 1, pp. 47-51, pi. iv, figs. 12-22. 1889. Rhynchotreta, Nbttblboth. Kentucky Fossil Shells, pp. 84, 85, pi. xxxii, figs. 58, 59, 62, 63. Elongate-triangular, strongly plicated shells with fold and sinus normal, in adolescent and mature stages ; long and broad cardinal slopes ; beak erect, acu- minate and produced on the pedicle-valve. Foramen at maturity apical, its upper margin encroaching on the substance of the valve. Deltidium very conspicuous, convex, the component plates, in their later development, being anchylosed along the median suture. Dental lamellae vertical, resting on the bottom of the valve and enclosing a deeply impressed muscular scar; diductor scars elongate- flabelliform, divided by oblique ridges into anterior and posterior members ; 186 PALEONTOLOGY OF NEW YORK. adductor impression central, elongate and very small. The brachial valve bears a median septum which extends for one-half the length of the shell; being divided toward its posterior extremity, each branch supporting one process of the divided hinge-plate. The crura are long, slightly curved and somewhat expanded at their tips; between these there is a small, simple, cardinal process. External surface covered with exceedingly fine, filiform, papillose, concentric lines. Shell-substance fibrous, impunctate. Type, Terebratula cuneata, Dalman. Wenlock and Niagara groups. Observations. The elongate-triangular outline and the surface-ornamenta- tion of the only species that can now be referred to this group afford external peculiarities which at present appear to be of considerable importance. Many rhynchonelloids show slight evidence of a reversal of the relative convexity of the two valves in the process of growth ; here, however, this reversal is a feature which is conspicuously apparent in the mature shell, on account of its accomplishment only at a late stage in its development; hence the umbonal region of the sinus-bearing valve is convex, and that of the fold-bearing valve concave, for nearly one-half the length of the shell.* The great size and elevation of the deltidial plates and their unusual con- vexity are also peculiarities which characterize the mature condition of the shell. In the interior the brachial valve has somewhat the same construction as in Rhynchotrema, that is, shows coexistence of a median septum, slender and simple cardinal process and discrete hinge-processes. Their relative de- gree of development, however, is different, and in the structure of the pedicle- valve, its dental lamellae and muscular scars, the diversity is notable. We are inclined to regard these differential characters as forming a good basis for the generic (or subgeneric) distinction of the species, f The American representa- * For a full discussion and illustration of the nature of this reversal in contour and also of the develop- ment of the deltidial plates, see Memoirs New York State Museum, vol. i, No. 1, pp. 47-51, pi. iv, figs. 12- 22. 1889. t It is necessary to correct here certain errors in the original description of the genus Rhtnchotrbta. One is an ei-ror of assumption, that the crura united to form a terebratuloid loop ; subsequent examinations prove them discrete, somewhat curved and explanate at their extremities. Another, that the substance of the shell is finely punctate. BRACHIOPODA. 187 tive of R. cuneata has been regarded as a variety of the specific type, var. Americana, Hall. It occurs sparingly in the Niagara fauna of New York, but abounds at Waldron, Indiana, and is not uncommon in the dolomites of Illinois and Wisconsin. In Great Britain, however, the species appeared earlier, being found, according to Davidson, in the Lower Llandovery if not even in the Upper Caradoc. Genus S T E N 0 S C H I S M A, Conrad. 1839. PLATE LVI. 1839. Stenoscitma. Cosrad. Second Ann. Rept. Palseont. Dept., p. 59. 1859. Hhynchonella, Hall. Paleontology of New York, vol. iii, p. 236, pi. xxxv, figs. 6 a-y. 1867. HletwcUma, Hall. Palaeontology of New Yoik, vol. iv, jip. 334, 335. Mr. CoNBAD, in speaking of the rocks and fossils of the State of New York, in his Second Annual Report (p. 59), makes use of this term for shells, the only representative of which specified by him, is "the common Silurian bivalve Terebratula Schlotheimii, Von Buch." The T. Schlothdmi is a well-known Per- mian, not Silurian species, and some writers, notably Dr. CEhlert in Fischer's Manuel de Conchyliologie, have considered it necessary to apply the term Stenoschisma (Stengscisma as written by Conrad) in accordance with the characters of von Book's species, which renders it equivalent to Kino's genus, Camarophoria (1845). It is important in such a matter to get as near as possible to Mr. Conrad's intentions ; that he was at a disadvantage in draw- ing comparisons or making identifications of American with European species is evident from his characterization of T. Schlotheimi as a " common Silurian bivalve." Unquestionably he had before him at the time, and intended by this designa- tion some New York species, and in Volume IV of the Palaaontology of New York (p. 334) the author states that Mr. Conrad had used this name on a lith- ographed but unpublished plate of the fossils of the Lower Helderberg group, to designate a species subsequently described* as Rhynchonella formosa, Hall. This is as close an approximation to Mr. Conrad's conception as is now possible * Palaeontology of New York, vol. iii, p. 236. 188 PALAEONTOLOGY OF NEW YORK. and we should feel justified in assuming Rhynchonella formosa to be the type of the genus rather than to reject the well-established term Camarophokia and substitute Stenoschisma for it. Upon reviewing the Devonian shells which were referred to Stenoschisma in Volume IV of the Palaeontology of New York, it has become evident that some modification may be necessary in the application of that term. The in- ternal structure of the type-species R. formosa was not at that time demon- strated, nor, so far as we are aware, has it since been determined with the accuracy now required. The Stenoschismas of Volume IV are characterized by a strong septum in the brachial valve, cleft posteriorly, each lateral branch supporting one of the crural bases ; the latter are thus separated medially by the triangular cleft whose base is the divided median septum. An elongate umbonal cavity is thus formed beneath the hinge-plate, and this must be re- garded of some morphological significance in the relation of these shells to Camarophobia and its allies. The species possess no cardinal process, and the teeth are supported by parallel vertical dental lamellae. These characters are not shared by Rhynchonella formosa. In this species all our preparations show that the septum of the brachial valve is represented only by an exceedingly obscure median thickening, being in fact virtually wanting; there is no such median subcardinal cavity as above described, but the hinge- plate is divided by a fissure which extends to the bottom of the shell, and contains a slender longitudinal cardinal process; the divisions of the hinge- plate are not large, have concave upper surfaces, and the crura, which are long, recurved and expanded at their extremities, are produced from the inner angles of these divisions without interruption. The dental lamellae of the pedicle- valve are short and convergent. The surfaces of the dental sockets, which in the Devonian species are sometimes crenulated, are here smooth. It is neces- sary to recognize the importance of these palpable difierences in R. formosa and the group of shells ascribed to Stenoschisma in the work referred to, and it seems necessary to render to this genus a stricter construction than it has here- tofore received. In so doing R. formosa will stand as the only known repre- sentative of the type of structure described, and we are inclined to recognize BRACHIOPODA. 189 in it a nearer relationship to Rhynchotrema, than to the Silurian and Devonian representatives of Camarotcechia ; in other words, the existence or absence of the median brachial septum should be regarded as of less significance than the co-existence of a similar type of hinge-structure. In exterior characters Stenoschisma formosa is a trihedral, strongly plicated shell with well-developed fold and sinus, of an expression not uncommon throughout the Devonian rhynchonellids. Genos camarotcechia, nom. nov. • PLATE LVII. 1841. Atrypa, Conrad. Ann. Rept. Palaont. Dept. N. Y., p. 55. 1843. Atrypa, Hall. Geology of New York j Rept. Fourth Dist. ; Tables of Organic Remains, No. 66, figs. 3, 4 ; No. 67, fig. 2. 1847. Atrypa, Hall. PalsBOntology of New York, vol. i, pp. 21, 23, pi. iv (bis), figs. 7, 9. 1852. Atrypa, Hall. Palaeontology of New York, vol. ii, p. 70, pi. xxiii, figs. 4, 5 ; p. 274, pi. Ivii, fig. 1 i p. 279, pi. Iviii, figs. 3, 4. 1857. RhywlumeHa, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 78, figs. 1-7 ; p. 82, figs. 1-3 ; pp. 81, 86. 1860. RhynchoneUa, Billihob. Canadian Journal, vol. v, pp. 271, 272. 1860. RhynchoneUa, Hall. Thirteenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 87, 88. 1862. RhynchoneUa, A. Winchbll. Proc. Acad. Nat. Sci. Philadelphia, pp. 407, 408. 1862. RhynchoneUa, BiLLiNas. Palseozoic Fossils, vol. i, pp. 141-143, figs 118-120. 1863. RhynchoneUa, Hall. Transactions of the Albany Institute, vol. iv, pp. 215, 216. 1867. Rliynehanella (Stenocisma), Hall. Palseontology of New York, vol. iv, pp. 335-345, 348-353, pi. liv, figs. 1-59; pi. liva, figs. 1-23, 44-49 ; pi. Iv, figs. 1-52. 1879. RhynchoneUa, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., pp. 163, 164, pi. xxvi, figs. 12-33. 1882. RhyncJumeUa, Hall. Eleventh Ann. Rept. State Geologist of Indiana, pp. 305-307, pi. xxvi, figs. 12-33. 1884. RhynchoneUa, Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 152, pi. xiv, fig. 3 ; pi. xv, fig. 6 ; p. 155, pi. xiv, fig. 8. 1887. RhynchoneUa, Gossblbt. Annates de la Soci6t6 Geologique du Nord, vol. xiv, p. 188, pU. i-iii. 1888. RhynchoneUa, Hbbbick. Bulletin Labor. Denison Univeraity, vol. iii, pp. 39, 40, pi. v, fig. 1 ; pi. vii, fig. 26 ; pi. x, fig. 9. By restricting the application of the term Stenoschisma to shells agreeing in hinge-structure with RhynchoneUa formosa, the necessity is created for a new designation for the large group of shells to which that term was applied in 1867.* While these shells are susceptible to considerable variation in exterior, * PalsBontology of New York, vol. iv. 190 PALJEONTOLOGY OF NEW YORK. they usually maintain a full trihedral contour with shallow pedicle-, and con- vex brachial valves, evincing little, if any evidence at maturity, of a reversal of the relative convexity of early growth, a feature so apparent in some of the other groups of the rhynchonelloids. Their distinctive characters, however, are internal ; the median septum of the brachial valve is divided posteriorly in such a manner as to form an elongate cavity, which does not extend to the bottom of the valve. Each branch of the septum supports one of the lateral divisions of the hinge-plate, to which are attached the curved crural processes. In normal conditions of development the median interspace of the hinge-plate is not closed. The dental sockets, bordering the hinge-plate, are crenulated in the species which are assumed as representing the typical characters of the group. There is no cardinal process. In the pedicle-valve slender vertical lamellae support the rather small teeth and extend well into the cavity of the valve, enclosing a deep and narrow pedicle-scar. This is a group of shells highly developed in species, and eminently charac- teristic of the Devonian faunas, and hence the Rhynchonella congregata, Conrad, is designated as the type of the genus. This species is abundant in the condition of excellently preserved internal casts, in the sandy shales of the Hamilton group of central and eastern New York. The type of structure is, however, much older, probably as ancient as the early Trenton faunas of the Lower Silurian, where it seems to be represented by the species Rhynchonella altilis and R. plena, Hall, of the Chazy limestone.* In the succeeding faunas of the Silurian are R. fringilla and R. glacialis, Billings, from Division I, of the Anticosti series ; R. aequiradiata. Hall, of the Clinton group ; R. obtusipUcata, Hall, of the Niagara group, and it may prove that R. Indianensis, R. neglecta, R. Whitii and R. acinus, Hall, from the same faunas of New York and Indiana, also belong here, though their external habit, i. e., small size, compressed or elongated valves, is not usual in this group. At the appearance of the Lower Helderberg faunas, with their multiplicity of rhynchonellids, this type of structure appears to have *Thi8 opinion is based upon aerial transverse sections of the shells ; since no separated valves or satis- factory internal casta of these species have been obtainable. BRACHIOPODA. 191 yielded somewhat to the robust forms possessing a cardinal process, which are referred to the genus Uncinulds. We have not been able to obtain exhibitions of the hinge-structure in all these numerous forms and consequently reserve an opinion with regard to the proper association of some of those of less common occurrence. It is, however, interesting to find the structure of CAMAROTtECHrA possessed by the extravagantly gibbous species R. ventricosa, as precisely the same combination of external and internal characters reappears in the later faunas of the Waverly group. In the Oriskany sandstone we meet with a number of large and ponderous rhynchonellids which furnish some important evidence as to the values of the characters upon which the classification here adopted is based. In Rhynchonella Barrandii, Hall, which probably attained the greatest size of any of these species, the median division of the hinge-plate and the septal cavity appear to have been always present, a cardinal process absent. In R. speciosa, Hall, and R. pliopleura, Conrad, the younger shells have the same cardinal structure, but with increased age, probably for the most part after maturity, the median pit becomes obscured by the deposition of testaceous matter about the bases of the crura until no evidence of it remains but a linear median depression. This extreme is attained only in old shells, and the groove indicating the line of union of the lateral parts of the hinge-plate is never obliterated. Thus the hinge-plate takes on the appearance of a single solid lobe. In the pedicle-valve of young shells of all these species there is, close to the apex, evidence of very thin dental lamellae cemented to the lateral walls of the shell. The teeth, however, do not rest upon these, as their extremities are not free, but both in this stage of growth and always afterwards they are continuous with, and rest upon the lateral walls of the valve, as in the genus Rhynchotrema. The grada- tional variation indicated by these shells, in characters which in other groups are of indicial value according to their degree of development, leads to the con- viction that the homogenity of Camarot(echia as a zoological association will be better assured by removing these and similar species therefrom and applying to them a distinctive term of subordinate value, e. g., Plethorhyncha. Among the species of the Upper Helderberg, Hamilton and Chemung faunas, few will 192 PALEONTOLOGY OF NEW YORK. be found which present any material variation from the type of Camarokechia. Therefore, with our present knowledge, all the species definitely referred to Stbnoschisma in Volume IV of the PalsBontology of New York, may tentatively be embraced under this new term, that is : In the Corniferous limestone : Rhynchonella Tethys, Billings. Rhynchonella? Billingsi, Hall. In the Hamilton group : Rhynchonella Sappho, Hall. Rhynchonella Horsfordi, Hall. Rhynchonella congregata, Conrad. In the Chemung group : Rhynchonella eximia, Hall. Rhynchonella Stephani (or Stevensi), Hall. Rhynchonella Carolina, Hall. Rhynchonella Sappho, Hall. Rhynchonella prolifica, Hall. Rhynchonella Dotis, Hall. Rhynchonella carica. Hall. Rhynchonella duplicata, Hali. Rhynchonella contracta, Hall. Rhynchonella orbicularis, Hall. The type was continued further upward into the early faunas of the Lower Carboniferous, where it is represented in the Waverly group by some of the species already named, R. Sappho, R. contracta,* and R. Sageriana and R. Marshall- ensis, A. Winchell. ♦ Acco«ling to the identifications by Pi-of. C. L. Hbrrick, Bull. Laboratoi-ieB Denison University, vol. iii, pp. 39, 40. 1886. BRACHIOPODA. 193 LIORHYNCHUS, Hall. 1860. PLATE LIX. 1842. Orfhis, Atrypa, Vandxbm. Geology of N. Y. j Rept. Third Dist., p. 146, fig. 3 ; p. 168, fig. 2 ; p. 182, fig. 2. 1843. Atrypa, Hall. Geology of N. T. ; Rept. Fourth Dist., p. 182, fig. 11 ; p. 223, fig. 2, Tables of Organic Remains, No. 67, fig. 1. 1855. Shynchonella, Shumard. Rept. Geol. Surv. Missouri, p. 205. 1860. Leiorhynchus, Hall. Thirteenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 75, 8.5, 86, figs, la, 6. 1860. RItynchoneUa f Billings. Canadian Journal, vol. v, p. 278, figs. 26-28. 1863. Hhynchonellaf Billings. Geology of Canada, p. 384, figs. 418a-c. 1866. Leiorhynchus. A. Winchbll. Rept. Lower Peninsula of Michigan, p. 95. 1867. Leiorhynchus, Hall. Palseontology of N. Y., vol. iv, pp. 355-364, pi. Ivi, figs. 1-49 ; pi. Ivii, figs. 1-29. 1868. RhynchoneUa, Mebk. Trans. Chicago Acad. Sci., vol. i, p. 93, pl. xiii, figs. 9a-c. 1873. Leiorhynchus, Hall and Whitfield. Twenty-third Ann. Rept. N. Y. State Cab. Nat. Hist., p. 240, pl. xi, figs. 25-27. 1874. Leiorhynchus, Nicholson. Geological Magazine, new ser., vol. i, p. 120. 1884. Wtynchonella, Leiorhynchus, Walcott. Monogr. U. S. Geolog. Survey, vol. viii, p. 153, pl. xv, figs. 1-4 ; pp. 157-159, pl. xix, figs. 5, 9. 1885. Leiorhynchus, Clarkb. Bull. U. S. Geolog. Surv., No. 16, pp. 24, 31, 33, 68, pl. iii, fig. 14. 1886. Wtynchonella, Ulrich. Contributions to American Palaeontology, p. 26. 1887. Liorhynehus, (Erlbrt. Fischer'^ Manuel de Conchyliologie, p. 1308. During the period of the predominance of the foregoing species of Camarotce- CHIA in the middle Devonian, certain shells, not essentially varying from them in internal structure, assumed a peculiar exterior expression, the fold and sinus becoming strongly plicated, while the lateral slopes are covered with low, faint or obsolescent duplicating ribs ; umbones smooth ; substance of the shell very thin. To this group the term Liorhynchus* was applied in 1860, and the typical species is the Orthis quadricostata, Vanuxem, of the Hamilton faunas. These shells constitute an interesting lateral line of development which was continued from the later Devonian into the early faunas of the Carboniferous, where it probably outlived its parental type. The species of the middle Devo- nian seem to have flourished most abundantly in the bituminous sediments of the Hamilton series. Thus in the Marcellus shales and limestones, shells of * Thirteenth Report New York State Cabinet of Natural History, p. 75. The original spelling of this term was Lbiorhynchus; as above given its orthography is probably less open to objection. The term is retained for these fossils, although the word was earlier in use for a recent genus of Vermes (according to AoASBiz), or Coleoptera (according to Dall). What its value may be in this latter use we are not informed, but at all events there is little danger of any confusion of intent in its application to gi'oups so remotely connected. 194 PALEONTOLOGY OF NEW YORK. the Liorht/nchus limitarts, Vanuxem, frequently constitute entire strata of some inches in thickness ; and also, in the more bituminous layers of the Hamilton group proper, L. multicostus, Hall, and at times, L. quadricostatus. Hall, become very abundant, and are correspondingly rare as the shales lose their organic matter and become more calcareous. In the black Genesee shales, L. quadri- costatus. Hall, is often abundant. Where the succession of the sediments was more persistently calcareous or arenaceous the shells adapted themselves to their surroundings, though under such circumstances not attaining so great development in individuals. In the calcareous layers of the Hamilton group at Thedford, Ontario, L. Laura, Billings,* is not of infrequent occurrence. L. Kelloggi, Hall, occurs in the upper Devonian Ccalcareous sandstones of northern Ohio ; L. mesacostalis, L. sinuatus. Hall, and L. globuUformis, Vanuxem.f in the sandstones of the Chemung group ; the L. Newberryi, Hall and Whitfield, from the Erie shales, of Devonian age ; the L. Greenianus, Ulrich, from the Knobstone formation of Keokuk age, and the L. Boonensis, Shumard, in the Burlington limestone. In the later representatives of this subgenus there is a tendency to obsoles- cence of the plications over the entire surface ; and in all specimens where the interior is well preserved, the muscular impressions of the brachial valve form narrow, elongate-oval scars alongside the median septum. Frequently, also, the narrow pit beneath the hinge-plate supported by the median septum, is of conspicuous size, as in L. globuUformis. The significance of the group of fossils embraced by the foregoing divisions, Camarotcechia, Plethorhynchus and LiORHYNCHUS cannot be gainsaid. The existence of an incipient spondyl- ium between the divisions of the hinge-plate, supported by the median septum, at once indicates a relationship, not so much to the pentameroids, which have for the most part preceded these in time, but to the spondylium-bearing shells of the later palaeozoic periods, Camarophoria and its allies. * Some of the more oblate forma of this species seem indistinguishable from L. mvlticostua. Hall, bat L. Laura normally has an elongate-oval outline which is not jwssessed by typical examples of the foimer. f Before us is a specimen of the Rhynchonella casianta. Meek, fi-om the Eureka District of Nevada, agreeing with Mr Walcott'h identification of this species as described in volume viii, Monographs of the U. 8. Geolo-iical Survey, p. 163. This specimen demonstrates a vei-y close specific similarity to Liorhynchus glol/tUybrmis, Vanuxem, and serves to fix its generic relations beyond doubt. BRACHIOPODA. 195 Genera (l)WILSONIA (Quenstedt), Kayser, 1871;(2)UNCINULUS, Bayle, 1878; (3) U N C I N U L IN A, Bayle, 1878 ; (4)HYP0THy' RIS (McCoy), King, 1850. PLATES LVIII, LX. Terebratula, J. Sowbrbt. Mineral Concholog-y, vol. ii, p. 38, pi. cxviii, fig. 2. Ancnnileg, Wahlb.nbeeq. Nova Acta Reg-. See. Upsal, p. 67. Terebratula, Dalman. Kongl. Vetenskapa. Akad. Handling., p. 139, pi. iv, fiy. 1. Terebratula, von Boch. Ueber Terebrateln, p. 47. Terebratula, von Buch. Deber Terebrateln, p. 68, pi. xi, figs. 29, a, h. Terebratula, J. db C. Sowerby. Silurian System, p. 615, pi. v, fig. 21 ; pi. vi, fig. 7. Alrypa, J. db C. Sowbbby. Trans. Geol. Soc. London, 2nd ser., vol. v, pi. Ivi, fig. 24 ; pi. Ivii, figs. 5, 6. Atrypa, Phillips. Pateoz. Foss. Coniwall, Devon and West Somerset, p. 84, pi. xxxiv, fig. 150. Atrypa, Vandxem. Geology of N. Y. ; Rept. Third Dist., p. 163, fig. 1. Atrypa, Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 215, fig. 1. Terebratula, F. Robmeb. Veratein. rhein. Uebergangsgeb., p. 65. Terebratula, db Vbr.vedil. Geol. de la Russ. et des Mont, de I'Oural, p. 87, pi. x, fig. 8. Hypothyris, King. Annals and Magazine of Natural Histoi-y, vol. xviii, p. 28. Atrypa, McCoy. Synopsis Siluiian Fossils of Ireland, p. 42. Hypothyrli, Phillips and Salter. Mem. Geol. Surv. Great Britain, vol. ii, pt. 1, p. 282. Hemithyris, d'Obbmjiy. Prodrome de Paleontologie, p. 92. Hypothyris, Ki»o. Permian Fossils of England, p. 111. Rhynchonella, Davidson. Annals and Magazine of Natural History, 2nd ser., vol. ix, pi. xiii. Rhynchondla, The Sandbbrgers. Verstein. des rhein. Schicht. Syst. Nassau, p. 43, pi. xxxiii, fig. 12. 1853. Rhynchonella, Schndb. Beschr. der Eifel. Brach., p. 185, pi. xxv, fig. 5; p. 187, pi. xxvi, fig. 3 ; p. 239, pi. xlv, tig. 4. RhynchoTuila, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 66, figs. 1-7 ; p. 68, figs. 1-3. Jthynchonella, F. Schmidt. Archiv (lir Naturk. Liv., Esth., und Kurlands, vol. ii. p. 210. Rhynchondla, Hall. Palseontology of New York, vol. iii, pp. 25-28, 30, pi. xxix, fig. 4 ; pi. XXX, figs. 1, 2 ; pi. xxxi, figs. 1-3 ; pi. xxxiii, figs. la-p. Rhynchonella, F. Roembr. Silur. Fauna des Westl. Tennessee, p. 72, pi. v, fig. 14. Rhynchtmella, Hall. Canadian Naturalist and Geologist, vol. v, No. 2, p. 146. Rhynchonella, Davidson. Bril. Silurian Brachiopoda, pp. 167-173, pi. xxiii, figs. 1-14. Rhynchonella, Hall. Paljeontology of New York, vol. iv, p. 346, pi. liva, figs. 24-43. Rhynchonella, Davidson. Brit. Silurian Brachiopoda, p. 166, pi. xxi, figs. 1-6, 28. Rhynchonella, de Vebneuil. TchihatchefTs Asie Mineure, Paleontologie, pp. 9, 468. Terebratula, (Juenstedt. Petrefactenk. Deutsch.; Brachiopoden, p. 193, pi. xlii, figs. 19-48. Terebratula, Quenstedt. Petrefactenk. Deutsch.; Brachiopoden, pi. xlii, figs. 15-18. Rhynchonella, Kayser. Zeitschr. der deutsch. geolog. Gesellsch., vol. xxiii, p. 502, Rhynchonella, Kayser. Zeitschr. der deutsch. geolog. Gesellsch., vol. xxiii, pp. 507-515, pi. ix, figs. 3, 4. (4) 1877. Rhynchonella, Hall and Whitfield. Geolog. Expl. Fortieth Parallel, vol. iv, p. 247, pi. iii, figs. 4-8. •The citations are numbered to correspond witli tlie generic titles. (1)" •■ 181K. (1) 1821. (1) 1828. (1) 1834. (4) 1834. (1) 1839. (4) 1840. (4) 1841. (4) 1842. (4) 1843. (4) 1844. (1) 1845. (4) 1846. (1) 1846. (1) 1848. (2) 1850. (4) 1850. (1) 1852. (4) 1852. (4) 1853. (2) 1857. (1) 1858. (2) 1859. (2) 1860. (1) 1860. (1) 1867. (4) 1867. (2) 1867. (2) 1869. (1) 1871. (4) 1871. (I) 1871. (4J 1871. 196 PALMONTOLOGY OF NEW YORK. (2) 1878. Uneinvliui, Bay lb. Explic. , pi. xi, figs. 5, 6. (2) 1879. RhyncUonella, Hall. Twenty-eighth Ann. Kept. N. Y. State Mus. Nat. Hist., p. 165, pi. xxvi, figs. 34-40. (2) 1883. Uncinulus, Waaobji. Salt-Range Fossils, Braehiopoda, p. 424. (1) 1883. iJAy7jcA(ni«//o, Davidsok. lirit. Silur. Braehiopoda; Suppl., p. 156. (2) 1884. Vncinulus, ffiHLKRT. Bull, de la Soc. g6ol. de France, 3d sei-., vol. xii, pp. 426-432, pi. xxi, figs. lo-« ; pi. xxii, figs. 2 a-n. (4) 1884. RhynchoiiMa, Walcott. Monogr. U. S. Geol. Surv., vol. viii, p. 157. (3) 1884. Rhynchonella, CEhlbbt. Bull, de la Soc. geol. de France, 3d sei-., vol. xii, p. 420, pi. xviii, fig. 5o-o. (4) 1884. Rhynchonella, Clarkk. Neues Jahrb. filr Mineral., Beilagebnd. iii, p. 385. (4) 1890. Rhynchonella, Williams. Bull. Geol. Soc. America, vol. i, pp. 481-600, pis. xi, xiii. (4) 1891. Rhynchonella, Clarkb. American Geologist, August, p. 100. There are large numbers of palaeozoic rhynchonellas which are characterized by a full subcuboidal or subpentahedral contour, a fold and sinus not sharply developed except at the anterior margin, an abrupt anterior slope, sharply ser- rated lateral margins of contact, and low surface plications, each of which, on the front of both valves, is marked by a fine median line. Shells with such external features appeared in the middle or upper Silurian, multiplied in the early Devonian, and continued their existence into the faunas of the Carboniferous. They were early distinguished as the group of Rhyncho- nella Wilsoni, Sowerby, taking their name from the common species of the Wenlock fauna, which was quite fully described and illustrated by Davidson in the Annals and Magazine of Natural History, 1852,* and still more elaborately in his Silurian Braehiopoda, 1869.f In 1871, QdenstedtJ termed the shells " die Wilsonier " or " the Wilsoni' s," introducing for them a trinomial nomen- clature, as, for example, R. Wilsoni Bohemica, R. Wilsoni pila, etc., etc. That this term was not intended as a generic or subgeneric designation is evident from its mode of use, but in the same year Professor E. Kayser,§ in referring to Quenstedt's recently expressed opinion, says that " the characters [mentioned] seemed to him [Quenstedt] sufficient for the establishment of a separate subgenus " Wilsonia." Thus the name Wilsonia was introduced, • P. 24», pL xiii, figs. 12-14. t P. 168, pi. xxiii, figs. 1-18. } Petrefactenkunde Deutschlands ; Brachiopoden, p. 193. { Zeitschrift der deutsch. genlog. Qesellsch., vol. xxiii, p. 602. BRACHIOPODA. 197 and by many European authors has been applied to shells of this character. Mr. Davidson did not adopt it ; Drs. Waagen and ffiHLERT* have objected to its admission on account of its morganatic introduction and have preferred to use the term Uncinulus, proposed by Bayle in 1878. A critical study of this group of subcuboidal shells has compelled the adoption of somewhat different conclusions than those expressed by other investigators in regard to their generic values and appropriate designation. Thus far the broader application of the term Wilsonia (a name which should be accredited to Kayser rather than to Quenstedt, the former being not only the first to use the term, but accompanying it with a careful account of the characters of the group), has rested mainly upon external features. Davidson did, indeed, as early as 1852, describe the muscular scars and interior apophyses both of R. Wilsoni, Sowerby, and also of R. sub- Wilsoni, D'Orbigny, the latter a lower Devonian shell from Nor- mandy (Nehou), and the type of Bayle's genus Uncinulus ;f and to (Ehlert| we owe a most careful delineation of the internal characters of the latter. Both of these species are characterized by the great size and depth of the diductor scars of the pedicle-valve, the thickened teeth unsupported by vertical lamellae, and both have a well developed median septum in the brachial valve. But they differ most conspicuously, and most importantly, in the structure of the hinge-plate. In R. Wilsoni (Wilsonia) the plate is very small, is divided medi- ally by a shallow incision into distinct crural bases, and has no cardinal process. In fact the structure is not unlike that of Camarotcechia, though never so highly developed as in the Devonian species of that genus. So far as we are aware, among the many figures of R. Wilsoni to be found in literature, none have been given which show the construction of this part; those upon Plate LVIII have been made from a clean internal cast of the American shell identified by DE Verneuil with R. Wilsoni, but subsequently termed R. Saffordi, Hall, and which occurs in the Niagara fauna of Perry county, Tennessee, at Louisville, Kentucky, and in the upper members of the Arisaig series, in Nova Scotia. • Dr. (Ehlbrt, in some of hia later papers, has withdrawn his objections and adopts Wilsonia (Quen- stedt), Kayser, in preference to Uscikllus, Bayle. t Explication de la carte giolog. France. 1878. I Bull. Society geolog France, 3d ser., vol. xii, pi. xxi, figfs. 1, a-s. 1884. 198 PALEONTOLOGY OF NEW YORK. On the other hand, the Devonian species, R. sub-Wilsoni, d'Orbigny, possesses a solid, undivided hinge-plate and a highly developed cardinal process, as was shown by Davidson, in 1852, and by (Ehlert, in 1884 ; and though having ex- ternal contour, median septum and unsupported teeth, as in R. Wilsoni, should not be placed in too intimate association with the latter. The generic charac- ters of R. suhwilsoni are positive, those of R. Wilsoni are unsubstantial. If WiLSONiA has any value as a distinctive designation it is subordinate to Cama- ROTCECHiA, and as such may serve to characterize the subcuboidal shells of this group which, like R. Barrandii, Hall, and the species constituting the proposed subgenus Plethokhynchus, have the teeth unsupported by dental lamellae. To adopt the name Wilsonia for all the shells possessing the internal characters of R. Wilsoni, without regard to external form, and thus make it the equivalent of the group Camarokechia, would be to deviate widely from the intent of the authors of the term ; hence, per contra, it becomes necessary to restrict the application of the name to very narrow limits. In American faunas the typical Wilsonia is but sparsely represented. With it may be placed the species R. Saffordi, Hall, to which reference has been made. Perhaps the R. ventricosa, Hall, of the Lower Helderberg fauna (Shaly lime- stone), a shell referred to in the discussion of Camarot(echia, should be associ- ated with it. Rhynchomlla Wilsoni is a species of wide distribution in the European Upper Silurian, and has been described in Great Britain, Sweden, Russia and Spain ; Davidson gave its vertical range as from the Llandovery to the Ludlow periods. It is probably true that the very few other species ol similar type of exterior, which have been described from the Wenlock and equivalent faunas, are congeneric, but this statement can be made only with reservation. Bayle, in 1878, proposed* to use the term Uncinulina for a species described by him as Uncinulina fallaciosa, from the lower Devonian of Nehou and else- where. To Dr. (Ehlert, again, we owe the elaboration of this shell, f The species is subcuboidal in form, less globose than R. Wilsoni, but with the abrupt • Explication Carte gfiolog. France, Atlas, pi. xiii, fig«. 13-16. t Op. cU., p. 420, pi. xviii, figs. 5a-o. 1884. BRACHIOPODA. 199 anterior slope characterizing the entire group. The internal casts figured by (EuLERT show less highly developed muscular scars and testaceous thickenings, a somewhat irregularly divided hinge-plate supported by a median septum and slightly developed dental plates. The structure is, in short, very similar to that of WiLSONiA, and there appears to be no good reason for dissociating the shell from R. Wilsoni, inasmuch as the relative depth and size of muscular scars are features of but inferior importance. At all events, the type of structure seems to be the same as that which prevails among the earlier representatives of Camarotcechia. Bayle's species, however, bears no little resemblance to Sowerbt's Terebratula Stricklandi* of the Wenlock fauna, a species finely devel- oped in the Niagara faunas of Indiana, Illinois and Wisconsin. We have been supplied with beautiful internal casts of this species by T. A. Greene, Esq., of Milwaukee, obtained from the dolomites in that vicinity, and these show a peculiar conformation of the hinge-plate, the lateral components of which are divided medially for a portion of their length only, toward the apex the plates being curved upward and uniting, thus forming an arched and hollow process which is, of course, the representative of the cardinal apophysis in Uncinolus. This is a very simple condition of development of this process, and it is inter- esting to find it so early in the history of the group. The figure of the hinge- plate of R.falladosa given by (Ehlert (5/), is similar to the impression usually obtained from internal casts of R. Stricklandi, and it may be found that the French species possesses the incipient cardinal process of that shell ; in this event the term Uncinulina may have a certain value as a distinctive designa- tion for shells in this condition of development, but for the present it seems wiser to include R. Stricklandi within the limits of the genus Uncinulus. It is in the fauna of the Lower Helderberg group that the subcuboidal Rhyn- chonellas with a highly developed process, attain their characteristic and most extreme development. Dr. (Ehlert's figures of this process in Uncinulus sub- wilsoni show it to be a simple crescentic apophysis striated longitudinally, but in Rhynchmella mutabilis, R. abrupta, R. vellicata, and R. nucleolata, Hall, of the Lower Helderberg group, there is usually some evidence of a median division ; * Not Rhynchonella Stricklandi (Sow.), Schnur, which is a Devonian shell. 200 PALEONTOLOGY OF NEW YORK. frequently this is obscured to such a degree as to be observable only at the summit of the stout, erect process, as in R. vellicata, but in the other species its duplicate character is usually retained. Figures are given in this volume, showing the various forms of this process from a bidentate condition very sug- gestive of its appearance in the leptaenoid shells, to a condition in which the parts are firmly coalesced into a simple process. These various conditions are, in a certain sense, developmental, but are also features of specific value, though it should be observed that in old shells, where there is a tendency to extrava- gant secretion, the process is thickened, as are also the median septum and in- ternal walls of the valves. The term Uncinulus, embracing these shells, forms a very compact association, which, in American faunas, seems to leave its last trace in the R. speciosa, Hall, of the Oriskany sandstone, of which mention has already been made in the discussion of Plethorhyncha ; a shell which, in a senile condition, shows a tendency to the formation of a cardinal process. There is good reason to believe that this peculiar combination of characters was derived from the Rhynchotrema of the Lower Silurian, the shells having somewhat the same external aspect, while on the interior the unsupported teeth and linear cardinal process of Rhynchotrema point to this conclusion. At the same time it is worthy of remark that in the latter genus the cardinal process lying between the parts of the divided hinge-plate, seems to be a remnant of the median septum, while this apophysis in Uncinulus has evidently been formed by the subapical coalescence of the lateral components of that plate. The last of the strongly subcuboidal species to appear in the American Palaeozoic faunas are variants of the well-known horizon-marker, Rhynchonella (Atrypa) cuboides, Sowerby ; namely, R. venustula, Hall, of the TuUy limestone, R. Emmonsi, Hall and Whitfield, from the upper Devonian of the White Pine District of Nevada, and R. intermedia, Barris, from the upper Devonian of Iowa.* Rhynchonella cuboides, in European faunas, is indicial of upper Devonian age. Its representative in the Tully limestone, R. venustula, is associated with a fauna composed almost exclusively of the species of the Hamilton shales. * Mr. C. D. Waloott regpards the last named a synonym for M. Emmonsi. See Palaeontology of the Eureka District, p. 157. BRACHIOPODA. 201 The internal structure of these species has never been carefully elucidated, and it is a matter of great difficulty to obtain material suitably preserved for the elaboration of the critical features of the hinge. Clean internal casts are seldom found, and no instance of the silicification of the valves has come to our notice. By careful serial sectioning, however, it has been possible to ascer- tain with reasonable accuracy the character of the hinge. The teeth are usually supported by short vertical lamellae ; the hinge-plate is quite small and is composed of two broad, short lateral processes, which are divided, for a por- tion of their length only, by a median incision extending to the bottom of the valve but not forming an inceptive spondylium as in Camarot(ECHia. The dental plates are large. There is but the barest indication of a median septum in the brachial valve. The muscular impressions are small and not deep; those of the pedicle-valve making an oval scar continued from the narrow ped- icle-cavity ; those of the brachial valve being narrow, elongate and extremely obscure.* The interior of the pedicle-valve frequently preserves the ovarian pittings and vascular sinuses while the characters are but faintly retained on the brachial valve. The development of these features seems to be of specific or varietal value only, as they are more rarely shown in the European examples of R. cuboides and are absent in R. Emmonsi, which is a more finely plicated shell, possessing other internal structure here described. The characters described are distinctive, but that they also occur in such allied species of the middle Devonian as R. procuboides, Kayser, R. primipilaris, von Buch, and R. parallelepipeda, Bronn, we can only surmise from a similarity of exterior. They are reproduced with a very slight development of the median septum, in R. Grosvenori, Hall, of the St. Louis limestone. To shells of this nature may appropriately be applied the designation Hy- POTHYRis, King, 1846. There may seem to be some objection to the adoption of this term, which was introduced at an earlier date by Phillips f for certain * Davidson has ^ven, on plate ii, of his Supplement to the Devonian Brachiopoda, figures (19, 19a) of an intei-nal cast which is referred to R. niboides, but it would seem to I.e an erroneous reference. There is nothing in the figures which suggests this species, but it appears to repi-esent a concavo-convex shell with an extended beak and strong flabellate muscular scare on both valves ; in many respects suggestive of a species of EAroxrA. t Palteozoic Fossils of Cornwall, Devon, and West Somerset, p. 35. 1841. 202 PALEONTOLOGY OF NEW YORK. shells perhaps rhynchonelloid in character, but it has not been, nor will it ever be possible to determine the author's conception of the term from his very brief diagnosis : " Beak acute, perforation below it." No species was cited and the name was never used in such a manner as to lead to any notion of its intended significance. Recognizing the obstacles to the adoption of the term. Professor King re- defined it in volume xviii (p. 28) of the Annals and Magazine of Natural History (1846), deriving his diagnosis from the Atrypa cuboides, Sowerby, which he specified as the type of the group. It is evident from King's observations, both in the work cited and in his Permian Fossils (pp. 110-112, 1850), that he intended the term Hypothyris to replace Fischer de Waldheim's name Rhynchonella as an appellation for those shells, previously classed with the Tkrbbratolidm, which had a plicated exterior and an acute beak. Now that the state of our knowledge requires a narrower and more precise delimitation of these fossils, we are brought back to the original species, A. cuboides, as ex- pressing the restricted value of the genus Hypothyris, King, and that term will be adopted for this group of Rhynchonellas in preference to introducing a new one. Subgenus PUGNAX, s.-gen. nov. PLATE LX. 1809. Conchyliolithui antnnites, Martin. Pelrefacta Derbiensia, pi. xxii, figs. 4, 5 ; pi. xxxii, figs. 7, 8 ; pi. xxxiii, figs. 5, 6. 1822. Terebratvla, Sowbrby. Mineral Conchology, pi. cccxv, fig. 3 ; pi. cccxvi, figs. 5, 6 ; pi. cccxxiv ; pi. cccxxv, figs. 1-6. 1834. Terebrattda, von Buck. Ueber Terebrateln, p. 33. 1836. Ter^mitula, Phillips. Geology of Yorkshire, vol. ii, p. 222, pi. xii, figs. 4-12, 16, 17, 25-30. 1840. Atrypa, Sowbrby. Trans. Geol. Soc. London, 2nd ser., vol. v, pi. Ivi, figs. l.'i-lS. 1841. Terdnatula, Phillips. Palaeoz. Foss. Cornwall, Devon and West 'Somei-set, p. 86, pl. xxxv, fig. 154 ; p. 87, pl. xxxv, fig. 166. 1843. Terebratula, db Kosinck. Animaux fossiles de la Belgique, p. 278, pl. xvii, figs. 3a-/. 1845. Terebratula, db Vbrnbcil. Geol. de la Russ. et desMont. de I'Oural., p. 78, pl. x, fig. 1. 1855. HhyTichonella, Shuhard. Second Ann. Rept. Geol. Surv. Missoui'i, pl. c, fig. 5. 1858. BhyTichoTieUa, Hall. Transactions of the Albany Institute, vol. iv, p. 10. 1858. BhynchoTiella, Hall. Geology of Iowa, vol. 1, pt. 2, p. 668, pl. xxiii, fig. 2 a, b. 1858. Terebratula, Marcod. Geology of North America, p. 58. 1869. Camaroplioria, Shomard. Trans. St. Louis Acad. Sci., vol. i, p. 394. BRACHIOPODA. 203 I860. Rhyrtchkvnsov. British Carbon. Brachiopoda, pp. 93-105, pi. xx, figs. 1-13; pi. xxi, figs. 1-20 ; pi. xxii, figs, l-l.'j ; pi. xxiii, figs. 1-22. 1860. Khynchonella, McChbsnky. Trans. Chicago Acad. Sci , vol. i, pp. 49, 50. 1862. Rhynchonella, White. Proc. Boston Soc. Nat. Hist., vol. ix, p. 23. 1865. Rhynchonella, Davidson. British Devon. Brachiopoda, pp. 62, 63, pi. xii, figs. 12-14; pi. xiii, figs. 6-13. 1866. Rhynchonella, Mbek. Geological Survey Illinois, vol. ii, p. 153, pi. xiv, figs. 4a, b. 1868. Rhyiu-fionella, Mekk. Geological Survey Illinois, vol. iii, p. 450, pi. xiv, figs. 7a-(i. 1871. Terebratula, Qubsstkdt. Petrefactenk. Deutschlands; Brachiopoden, p. 190, jil. xlii, figs. 5-7. 1883. Rhynchonella, Williams. Amei-ican Journal of Science, vol. xxv, p. 91. 1884. Rhynchonella, Walcott. Monogr. U. S. Geol. Surv., vol. viii, p. 155, pi. xiv, figs. 7, 7a. 1885. Rhynclwndla, Clarke. Bull. U. 8. Geo!. Surv., No. 16, p. — . 1887. Rhynchonella, db Koninck. Faune du Calcaire Carboniffere de la Belgique, pt. 6, Brachiopodes, pis. ix, X, xi, xii. Diagnosis. Shells with deep fold and sinus; elevated, and often acuminate on the anterior margin ; more or less sharply plicated, the plications usually being simple, those of the fold and sinus the strongest, and those of the lateral slopes often obscure or obsolete. Pedicle-valve shallow ; brachial valve deep. Teeth supported by vertical lamellae ; hinge-plate similar in structure to that of Hypothyris ; the median septum of the brachial valve is extremely faint when present, but is usually undeveloped. Muscular impressions not large but well-defined and clearly subdivided. Vascular sinuses sometimes retained on the pedicle-valve, always obscure on the brachial valve. Type, Conchyliolithus anomites acuminatus, Martin. Carboniferous limestone. It is apparent that these shells, in the character of their internal apophyses, are not widely removed from those of the type of Rhynchonella cuboides. The contour of the .shells affords a difference of fundamental significance, and its trihedral expression in R. acuminata is the nearest approach, among palaeozoic species, to the form of the typical Rhynchonella, R. loxia. The group requires a distinctive name, and the term Pugnax has been selected as it serves to commemorate von Buch's term Pugnacea, which was applied to a division of the Rhynchonellas, embracing the typical forms of this sub-genus. This combination of characters appeared in the middle or later Devonian and during the various faunas of the Carboniferous became prolific in species. Among its representatives in American rocks are R. pugnus, Martin, and R. reniformis, Sowerby, of the Chemung faunas of New York; iZ. a/te, Calvin, from 204 PALEONTOLOGY OF NEW YORK. the Upper Devonian of Iowa ;* R. Missouriensis, Sliuiiiard, and R. striato-costata. Meek and Worthen, of the Choteau limestone; R. explanata, McChesney, of the Chester limestone; R. mutata, Hall, R. Ottumwa, White, of the St. Louis group; R. Uta, Marcou, R. Ealoniiformis, McChesney, and the Camarophoria Sivalloviana, Shumard, of the Upper Carboniferous limestone. Shells of this type of exterior abound in all later palaeozoic faunas. Genus EATON I A, Hall. 1857. PLATE LXI. 1841. Atrypa, Cokkad. Ann. Rept. Palsont. Depl. N. Y. Geol. Survey., p. 66, 1842. Atrj/Tpa, Vandxem. Geology of N. Y. ; Rept. Third Dist., pp. 120, 121, figs. 4, 5. 1843. Atrypa, Mathbb. Geology of N. Y. ; Rept. First Dist., p. 342, fig. 3 ; p. 343, figs. 3, 4. 1843. Atrypa, Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 148, fig. 3. 1867. Batonia, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 90-92, figs. 1-7. 1859. Batonia, Hall. Twelfth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 35-37, figs. 1-7. 1859. Eattmia, Hall. Palseontology of N. Y., vol. iii, pp. 241-243, 432-488, pi. xxxvii, figs. 1 o-y, 2 a-c; pi. xxxviii, figs. 14-26; pi. ci, figs. 1, 2j pi. cia, figs. 2-6. 1866. Batonia, Mbbk and Worthbn. Geol. Surv. Illinois, vol. iii, p. 396, pi. viii, figs. 2 a-d. Concavo-convex shells with median fold and sinus, and plicated or radiate- lineate exterior. Anterior margin deeply sinuate. From the beak of the pedicle-valve diverge two lateral cardinal ridges which limit a more or less distinct false area. On the interior the teeth are adnascent to the lateral walls * The Rhynchunella alta, Calvin, which some American writers have considered equivalent to R. pug- niu, Martin, is a local form retaining quite peitdstently the features of II. anisodonta, Phillips (R. pugnus, var. anisodonta, Davidson). Though always smaller than the representatives of R. pugnus, occurring in the High Point (New York) fauna, at the base of the Chemung series, it less frequently shows a tendency toward the acute actt.minata\\ke fold than the latter. The fact that the New York shell evinces gradations in form which include both the pugnus and the acuminata type of exterior is but a further substantiation of the argument upon which McCoy, in 1852, reduced the latter to a variety of the former. This position has been contested by Davidson and other writers, who nevertheless note the great variability of the shells {lassing under these two names. That it may be convenient to retain both terms is undoubtedly true, but the ]>a8sage of one series of foi-ms into the other is quite as apparent among the Devonian as among the Carboniferous shells. It may be a fair question whethev the Devonian shells passing as R. pugnus and R. acuminata ai-e entitled to these names ; whether, for instance, it would not be belter to retain Phillip's name, R. anisodonta, for the former, and, possibly, R. triangularis, Sowerby, foi- the latter. In both of the former cases the originals were from the Carboniferous limestone of Dei-byshire and attained, as a usnal habit, a much greater size than the Devonian shells. The American Carboniferous shells representing the specific type of y{. pugnus, namely, R. striato-costata. Meek and Worthen, R. Missouriensu!, Shumard, bear a fine rat. 2, p. 116. Shells of comparatively large size at maturity, subtriangular in outline; biconvex, the convexity of the brachial valve being the greater. Fold and sinus very broad, and developed in the usual manner, on brachial and pedicle- valves respectively. On the pedicle-valve the apex is obtuse, not elevated, and is very broadly truncated by a large circular foramen, which, even in the earliest growth-stages observed, is enclosed for fully five-sixths of its periphery by the substance of the valve. The deltidial plates are incipient at maturity and scarcely evident in young shells ; the delthyrial margins are extremely divergent. The cardinal line is short but straight, and its extremities are produced on each side to form a short alate process or wing, similar to those in the genus Eumetria. These extensions occur on both valves, and are very apparent in the younger shells, but become somewhat obscured with the increase of convexity accompanying maturity. On the interior, the teeth are large and blunt, and attached to the lateral walls of the shell, though they also rest upon the thick lamellae similarly attached except at their anterior margins, and which converge downward to BRACHIOPODA. 207 form a deep, broad, transversely striated pedicle-cavity. The thickened lateral margins of this impression are continued anteriorly to about the center of the shell, forming an elongate-quadrate diductor scar which encloses a small oval adductor. The brachial valve has a convex umbo, showing no evidence of concavity in early stages of growth. Beneath the beak is a very fine, vertical, linear cardi- nal process which appears to be continuous with an obscure median longitudinal ridge, traversing about one-half the length of the valve. Both of these are frequently involved in the shell-substance and evident only in sections of the shell. The hinge-plate is deeply divided medially, each lateral portion being supported by a deep vertical septum resting on the bottom of the valve. The upper surfaces of the hinge processes are obliquely concave the outer and anterior angle being much elevated and the slope thence to the dental sockets abrupt. The crura are attached to the inner margins of these plates, are not curved, but their distal extremities are expanded into spoon-shaped processes which have their concave surfaces toward the brachial valve. Their are no thickened muscular scars as in the opposite valve. The surface is covered with sharply angular, simple plications, most of which begin in the umbonal regions, and the broad fold and sinus may bear as many as from eight to twelve of these. All the plications are crossed by fine, sharp concentric lines of ornamentation, which crenulate the summits of the ridges. Shell-substance fibrous, impunctate. Type, Rhynchospira nobilis. Hall. Hamilton group. Observations. The peculiar structure of this shell involved the earlier de- termination of its generic relations in much doubt. It was described in the Thirteenth Report of the State Cabinet of Natural History (p. 83, 1860), as Rhynchospira nobilis, and in Volume IV of the Palaeontology of New York (p. 412, 1867), it was referred to Trematospira ? The acquisition of new material* from the Hamilton group at Thedford, Canada, has afforded the means of de- monstrating that the shell is not spire-bearing. The external aspect of the * Largely by the favor of Professor Samobi. Cii,yiv, of Iowa City, Iowa. 208 PALEONTOLOGY OF NEW YORK. shell in both its young and immature conditions is, in a certain measure sug- gestive of Rhynchotreta, a resemblance increased by the peculiar concentric ornamentation of both, but lessened by the low, truncated beak of the pedicle- valve of Cyclorhina. On the interior the structure is altogether different. The shell presents a rare combination of structural features which have been observed only in the single species mentioned. It seems to approach most nearly to the type exemplified by Waaoen's genus Terebratoloidea, especially in the structure of the deltidium and foramen. It is elsewhere observed that variations in the foramen and deltidial plates among the rhynchonelloids were largely features of developmental value. In this case, however, the great encroachment of the foramen on the substance of the valve must have been fully effected at a very early stage of growth, for in the youngest shells observed it is as extremely developed as in mature indi- viduals. The alate or auriculate character of the cardinal extremities is a dis- tinctive feature, while the slight development of the median septum and cardinal process may not be regarded as of much significance in a comparison with Terebratuloidea. The straightness of the crura is a feature quite un- usual among the rhynchonelloids, perhaps nowhere so marked as here, while the concave expansion of their extremities is of more frequent occurrence. Gends terebratuloidea, Waagen. 1883. 1862. Rhynchonella, Davidson. Quarterly Journal Geol. Soc. London, vol. xviii, p. 29. 1863. Rhynchonella, Db Koninck. Fossiles paleozoiques de I'lnde., p. 36. 1883. Terebraiuloidta, Waagen. Salt- Range Fossils; Brachiopoda, pp. 413-424, pi. xxxiii, figs. 1-12. Diagnosis. " Shell more or less transversely oval or rounded, in its general appearance Rhynchonelloid, with strongly plaited valves and a high median fold in the dorsal and a corresponding sinus in the ventral valve. Hinge-line curved, beak truncated with a terminal round foramen ; deltidium formed of two distinct plates, which limit the foramen below only for a very short distance. " Internally, the ventral valve with two strong hinge-teeth, which are, how- ever, not supported by dental plates. The dorsal valve bears a tolerably large triangular hinge-plate, which is united on both sides by the deep dental sockets. BRACHIOPODA. 209 and is triangularly cut open in the middle up to the very apex of the valve, which also is a little cut out. There is no cardinal process. On both sides of Fig. ise. fig. 157. fio. 158. Terebratuloldea Davidsoni, Waagen.; Fig. 150. View of tlic exterior. Fig. 157. luteriorof the pedicle- valve. Fig. 158. Interior of the brachial valve. (Waagen.) the median incision very short curved crura take their origin, and proceed for a short distance in a slightly diverging direction towards the interior of the shell. There is no median dorsal septum. " The muscular and vascular impressions are not sufficiently distinct to be described accurately." (Waagen, op. cit, p. 414.) Type, Terebratuloldea Davidsoni, Waagen. Permo-Carboniferous, Observations. The difference existing between these shells and those con- stituting the subgenus Pugnax, appears to be mainly in the constant presence, in all later growth-stages, of a large apical truncating foramen. Dr. Waagen makes this a feature of first importance. Its character at maturity and its presence in immature phases of the shell are a repetition of the facts observed in Cyclorhina nobilis ; like the latter, also, the exterior of the shell suggests a spire-bearing interior, and Waagen mentions his surprise at the discovpry that his shells were rhynchonelloid. But for the presence of this highly developed foramen it would be difficult to distinguish the Indian shells from some of the small species of the American Upper Carboniferous faunas, belonging to the subgenus Pugnax, which have the foramen normally concealed at maturity and but partially enclosed at any stage of growth. In the former it is fully devel- oped at an early stage and maintained throughout the subsequent history of the individual. The relation of Terebbatdloidea to Pdgnax thus appears to be that of a senile to an immature condition of development. 210 PALEONTOLOGY OF NEW YORK. Gen08 RHYNCHOPORA, King. 1856. PLATE LVin. 1844. T^nbratula, db Vbrnrdil. Bull, de la Soc. g&ol. p/ioria, King. Monogr. Permian Fossils of England, pp. 113-122, pi. vii, figs. 10-32; pi. viii, figs. 1-8. 1854. Camar<>i>horia, Davidson. Introd. Bi-itit-h Fossil Brachiopoda, p. 96, pi. vii, figs. 108-113. 1856. Mhychoiietla, Siidmakd. Geology of Missouri, p. 204, j>l. c, figs. 5 6, 5 c. 1867. Caiuarophiiria, Davidson. British Permian Brachiopoda, pp. 23-28, pi. ii, figs. 16-31. 1857. Cainarophoria, How.sk. Annals and Magazine of Natui-«1 History, vol. xix, second series, p. 50, pi. iv, figs. 3, 4. 1858. Camarophoria (.»), Shbmard. Trans. St. Louis Acad. Sci., vol. i, p. 296, pi. xi, fig. 2. 1858. Rhynchonella, Hall. Transactions of the Albany Institute, vol. iv, p. 11. 1860. Camartrphoria, Davidson. British Carboniferous Brachiopoda, pp. 113-118, pi. xxiv, figs. 9-22 ; pi. XXV, figs. 1-12. 1860. Wiyncfumella, Swallow. Trans. St. Louis Acad. Sci., vol. i, p. 653. 1860. Bhyiichonella, Mbi^k and Worthkn. Proc. Acad. Nat. Sci. Philadelphia, vol. iv, second series, p. 451. 1861. Camarophoria, Gbinitz. Dyas, p. 84, pi. xv, figs. 33-48. 1862. Rhynchonella, Whitb. Proc. Boston Soc. Nat. Hist., vol. ix, p. 23. 1862. Penta.merus, Whitk and Whitfield. Journal Boston Soc. Nat. Hist., vol. viii, p. 295. 1866. Camarophoria, Davidson. Bi-itish Devonian Brachiopoda, p. 70, pi. xiv, figs. 19-22. 1866. Camarophoria, Mbbk and Worthbn. Geol. Survey of Illinois, vol. ii, p. 251, pi. xviii, fig 7. 1868. Rhynchonella, Mkek and Worthbn. Geol. Survey of Illinois, vol. iii, p. 450, pi. xiv, fig. 7. 1881. Camarophoria, Millbk. Journal Cincinnati Soc. Nat. Hist., vol. iv, p. 8, pi. vii, fig. 7. 1882. Cameroplwria, Worthkn. Bull. Illinois State Museum, No. 1, p. 39. 1882. Camarophoria f, Whitfield. Bull. American Mus. Nat. Hist , p. 54, pi. vi, figs. 35-39. 1883. Camarophoria, Waaqen. Palieontologia Indica, ser. xiii, vol. iv, p. 435. 1883. Caiaerophoria, Worthkn. Geological Survey of Illinois, vol. vii, p. 318, figs. a~c. 1883. Camarophoria, Hall. Twelfth Rept. State Geologist Indiana, p. 334, pi. xxix, figs. 35-39. 1887. 8tenogchisma, CEulkrt. Fischer's Manuel de Conchyliologie, p. 1309, fig. 1095. Diagnosis. Subtrigonal, concavo-convex rhjnchonelliform shells, with median fold and sinus well developed, and surface more or less strongly plicated. Beak sharp, incurved ; deltidial plates in an incipient condition, often wanting. In the pedicle-valve the dental plates converge, forming a moderately large spondylium which, in the umbonal region, rests upon the bottom of the valve, but anteriorly is supported by a vertical median septum. The spondylium is BRACHIOPODA. 213 short, while the supporting septum is carried beyond it, sometimes to nearly one-half the length of the shell. Near the teeth, which are small, there are two accessory supporting lamellae abutting on one side against the outer surface of the converging dental plates, and on the other against the interior cardinal surface of the valve ; thus enclosing small lateral umbonal cavities. Muscular scars of this valve always obscure. In the brachial valve the cardinal plate is narrow, subtriangular, in the typical species bearing a very small cardinal process, which in other species is rarely present. The hinge-plate is traversed by two fine, divergent ridges running outward from the beak and continuous beyond the anterior edge of the plate into long, slender and upwardly curving crura. Beneath the crura arises a broad, shallow, trough-shaped plate, which, near the apex, is supported by a short median septum resting on the valve. This process is strongly curved toward the opposite valve and is continued for most of its length beyond the termination of the median septum. Usually it widens outwardly, and then narrows rather abruptly, or even acutely, to its extremity. The adductor muscular scars are well developed in this valve, forming a broadly oval or sub- circular impression. Vascular sinuses are sometimes retained on both valves. Type, TerebratuJites Schlotheimi, von Buch.* Permian. Observations. According to our present knowledge, this genus represents the latest appearance of the camarellid interior. Its relations to the various groups of the rhynchonellids is largely, and we may say with a single reservation, wholly external. Species of Camarotcechia do develop, in the brachial valve, an elongate cavity on the summit of the median septum ; this is always in an in- cipient condition and is attained quite independently of any association with, or derivation from Conchidium and its allies. From this source may have come the brachial spondylium of Camarophoria, though the mode of attachment beneath, instead of in continuity with the hinge-plate, may perhaps render such assump- * Davidsoh, at various times, expi-eseed the opinion that this specific term should be regarded as a syn- onym for Marti.n'8 Conchy HoJ it hus anomites crumena, from the Carboniferous limestone. There are some differences in the two shells as described and illustrated by Mr Davidson, and as the typical forms of each are from distinct faunas it is wiser to keep them apart.i;^The Permian shell is the type of Camakophoria. 2U PALEONTOLOGY OF NEW YORK. tion open to question. No observed rhynchonellid has a septum or evinces any tendency to the formation of a spondylium in the pedicle-valve, as in Camaro- PHORiA. Camarophobia is a genus combining a modified pentameroid interior with a rhynchonelloid exterior. The genus appeared in the early Devonian, when the prevalence of the pentameroids was past, and species of Camarotce- CHIA were on the increase. Its earliest representative in American palaeozoic faunas seems to be a shell which occurs in the Corniferous limestone of Cass county, Indiana, and which is hardly distinguishable from the middle Devonian forms referred to the Terebratula rhomboidea, Phillips.* This American shell, the occurrence of which has not before been noted, corresponds with the Devo- nian shells figured by Davidson, though nearly all the specimens give some evidence of lateral plications about the margins. No opinion will be here expressed as to the specific identity of these Devonian, Carboniferous and Per- mian shells, except to distinguish by the name, Camarophoria rhomhoidalis, the American Devonian species, from the Carboniferous shells described by Phillips as Terebratula rhomboidea. Representatives of the genus are never abundant in American faunas, and the species mentioned appears to be its only known example in the Devonian, f In the early Carboniferous faunas are a few well-defined species : C. ringens, Swallow, from the chert beds of the Burlington limestone ; C subirigona, Meek and Worthen, from the Keokuk group ; C. Wortheni, Hall, and Rhynchonella sub- cuneata, Hall, from the St. Louis formation. The species C. Giffordi, Worthen, has been described from the Coal Measures, and C. bisulcata and C. Swallovana, Shuinard, from beds considered to be of Permian age. J * Phillips' species was based upon specimens fi-om the Carboniferous limestone of Bolland (Geology of Yorkshire, p. 222, pi. xii, figs. 18-20. 1836). Later, in his Palteozoic Fossils of Cornwall (p. 88, pi. xxxv, 6g. 158. 1841), he i-eferred the Devonian shell to the same si>ecies, and is followed by Davidson and other authors in ascribing to this species a range from the Devonian into the Permian, where it passes under the name of C. y/o6u/i7ui, Phillips (see Davidsou, Carboniferous Brachiopoda, p. 115; Devonian Brachiopoda, p. 70; Kayser, Zeitschr. der Deutsch. geolog. Gesellsch., vol. xxiii, p. 529). t The shell described in Volume IV of the Palaeontology of New York (p. 368) as Camarophoria EucharU, Hall, from the Corniferous limestone, is spirigerous, and has been taken as the type of the proposed genus Camabohpira. t The Camarophoria globulina, (Phillips) Davidson, and C. Dawauniana, Davidson, from the upper Car- tioniferoos of Windsor, Nova Scotia, are not Camarophorias but rhynchonellids, similar to R. Via, Marcou. BRACHIOPODA. 215 There is considerable variation in exterior among the Camarophorias. C. Schlotheimi is a triangular or deltoidal shell with the plication clearly developed on fold and sinus, but obscure on the lateral slopes. The greater number of the European and Indian Carboniferous and Permian species have a similar exterior. In C. Schlotheimi, von Buch, and C. Humbletonensis, Howse, the margins of the shell are, normally, expanded as in some Devonian forms of Airypa reti- cularis. Camarophoria subtrigona, Meek and Worthen, C. isorhyncha, McCoy, are large subcuboidal species, while C. ringens, Swallow, C. caput-testudinis, White, and C. subcuneata. Hall, are acutely triangular in outline, with broad, concave cardinal slopes. The species of both the latter groups are strongly plicated throughout, while in C. ringens the surface also bears a fine radiate linea- tion. The Camarophoria (Pentamerus) lenticularis, White and Whitfield, from the Yellow sandstones beneath the Burlington limestone, at Burlington, Iowa, is a shell widely different from all the foregoing in external features. The valves are biconvex and their outline subcircular ; it has no fold and sinus and no plications, the surface being smooth and regularly arched. To associate it generically with the plicate trihedral Camarophorias requires an effort of the imagination. At the same time its internal characters are normal for Camaro- phoria, except that the broad, spatuliform spondylium rests upon the valve for most of its length, the median septum penetrating it and projecting above it into the interior cavity of the shell. It is proposed to signalize these differences, and thus to render the association constituting Camaro- phoria the more homogeneous, by giving this species the subgeneric designa- tion, Camarophorella. 216 PALEONTOLOGY OF NEW YORK. Gknds SYNTROPHIA,* gen. nov. PLATE LXII. 1861. Oamarella, Bilunos. Canadian Naturalist and Geologist, vol. vi, p. 818. 1862. Strlcklandiniaf, Billings. Palieozoic Fossils, vol. i, p. 85, figs. 77, 78. 1864. Oithis, A. Wi.nchkll. American Journal of Science, second series, vol. xxxvii, p. 229. 1883. LeptCBna, Triplegia, Wiiitfibld. Geology of Wisconsin, vol iv, p. 171, pi. i, figs. 6, 7 ; pi. iii, fig. 6 ; p. 172, pi. X, figs. 1, 2. 1888. Triplesia, Whitfikld. Bull. American Mus. Nat. Hist., vol. i. No. 8, p. 303, pi. xxiv, figs. 9-11. 1892. Syntrophia, Hall. • Palaeontology of N. Y., vol. viii, part i, p. 270. In considering the spondylium-bearing shells of the earlier faunas, there are great difficulties in the determination of positive taxonomic characters. The features of the exterior and, to a great degree, those of the interior, are plastic and variable, failing to assume that fixity of form possessed by their successors in later faunas, and upon which we depend for a proper conception of generic values. Here circumspection must be used, lest generic distinctions be too arbitrary, or too narrowly drawn on the basis of differences which, among later fossils, would properly be considered of higher significance. The earlier divisions must be allowed more elasticity, as the types they include are forma- tive and inconstant. The spondylium-bearing species of the Lower Silurian are mostly subtrihedral shells with the external aspect of Rhynchonella, but there are a few described species which have an exterior similar to members of the genera Protorthis and Billingsella, that is, they are small, transversely elongate in outline, with straight, well-defined cardinal area. Such are the Stricklandinia ? Arachne and S. Areihtcsa, Billings, of the Quebec group (Lime- stone No. 2) ; Orthis Barabuensis, A. Winchell, from the Potsdam sandstone of Baraboo, Wisconsin, and the Triplesia lateralis, Whitfield, of the Calciferous fauna of New York and Vermont. For these shells the name Syntrophia will be adopted, the last-named species being selected as the type of the group, since the material derived from various sources has afforded the means of obtaining a very clear conception of its external and internal features. " The TVipUsia lateralis, Whitfield, of the Fort Cassin beds (Calciferous sandstone), contains a spoon-shaped process in each valve, that in the pedicle-valve being supported by a median septum. It therefore becomes necessary to remove this form to a distinct genus and to a diffei-ent association, and it will be described and Ulostrated in its proper place under the name SYNTnormA." — Palseontology of New York, vol. viii, part i, page 270. (This note was printed in 1891.) BRACHIOPODA. 217 Triplesia lateralis* is a transversely elongate, biconvex shell, with a straight hinge-line whose length nearly equals the greatest diameter of the valves, and each valve is medially divided by an open delthyrium. The external surface is smooth, with fine concentric lines visible only about the margins ; the inner shell-layers show a strongly fibrous radiating structure without punctation. The pedicle-valve bears a more or less clearly developed median sinus and the brachial valve a broad, indistinct fold. On the interior the teeth are very small, lying at the extremities of the delthyrial margins and supported by dental plates which converge and unite before reaching the bottom of the valve. Thus is formed a deep but short spondylium, which is supported, near its apical portion, by a median septum, but is free for fully one-half its length. In the brachial valve there are also two convergent plates bounding the deltidial cavity, larger and stronger than those of the opposite valve. These plates may rest upon the bottom of the valve, and probably always do so toward the posterior extremity, but anteriorly they become free, forming a spondylium which is supported by a median septum extending beyond the anterior edge of the plate. Thus these two valves, which are very similar in exterior, the pedicle-valve being only slightly the more convex and with a low median sinus, are also closely alike on the interior, each being furnished with a spondylium. Adhering to this species, as typical of a peculiar generic structure, there seems no reason to doubt that Billings' species Stricklandinia ? Arachne and S. Arethusa should be associated with it. They are externally of the same character except that the surface of the former bears obscure radiating plica- tions. On the interior the septum supporting the spondylium is longer and projects anteriorly, and the description of S. ? Arachne states that in the brachial valve there is no median septum. While we have not had the opportunity of examining the originals of these species, it may be observed that in Syntrophia lateralis this septum is .so delicate as to be detected with difficulty in prepara- tions of the interior, but transverse sections of the valves do not fail to reveal it. • Whitpibld, Bull. American Museum of Nat. History, vol. i, No. 8, p. 303, pi. xxiv, figs. 9-11. 1886. 218 PALEONTOLOGY OF NEW YORK. The figures of Leptana Barabuensis, given by Whitfield, represent internal casts of both valves indicating the existence of a supported spondylium in each.* It may be that Billings' Orthis ? Armanda,j from the Quebec group, is an allied species with a radially striated exterior. The relations of these shells to Stricklandia = Stricklandinia are not remote in these points of structure, and it may be inferred that they represent the inception of the structure which is exhibited by the Stricklandinias of the later Silurian and the Devonian. In the contour of the exterior a slight varia- tion is presented by the Triplesia primordialis, Whitfield, J from the Potsdam sandstone of Adams county, Wisconsin, and the Camarella calcifera, Billings, from the Quebec group.§ By the greater development of the median fold and sinus the form of the shell becomes subtrihedral and resembles, not a little, some of the Trenton limestone species of Triplegia; but Camarella calcifera possesses a very small spondylium in the pedicle- valve and probably one in the brachial valve also. At present there seems no valid reason for excluding these shells from the genus Syntrophia. They evidently bear no relation to Triplegia. ♦ Geologry of Wisconsin, vol. iv, pi. i, &ge. 6, 7 ; pi. iii, fig. 6. t Palsozoic Fossils, vol. i, p. 303, figs, a, b, c. I (Jeolojfy of Wisconsin, vol. iv, p. 172, pi. x, figs. 1, 2. 1882. § Canadian Naturalist and Geologist, vol. vi, p. 318. 1861. BRACHIOPODA. 219 Genera (1) C AMARELL A, Billings, 1859; (2) P A R A ST ROPH I A, GEN. NOV.; (3) ANASTROPHIA, Hall, 1867. PLATES LXII, LXUI. (3) 1839. Tertbratula, J. db C. Sowkkby. Murchison'a Silurian System, pis. xii, xiii. (2) 1847. Atrypa, Hall. Palieontology of N. Y., vol. i, p. 144, pi. xxxiii, fig. 10. (3) 1848. Terebratula, Davidson. Bull. See. Geol. de France, second series, vol. v, p. 328. (3) 1848. Hypothyris, Salter. Mem. Geol. Survey Great Britain, vol. ii, p. 28J. (3) 1852. Atrypa, Hall. Palaeontology of New York, vol. ii, p. 275, pi. Ivii, fig. 2. (1) 185(5. Ati-ypa, Billi.ngs. Canadian Naturalist and Geologist, vol. i, p. 208, figs. 20-23. (2) 1857. Pevtamerus, Billisgs. Geological Sui-vey of Canada ; Rept. of Progress for 1856 ; p. 295 (3) 1857. Pentatnerus, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., p. 104, figs. 1, 2. (3) 18.'9. Pentamenis, Hall. Twelftli Rept. N. Y. State Cab. Nat. Hist., p. 77. (3) 1859. Pentamerus, Hall. Palieontology of New York. vol. iii, p. 260, pi. xlviii, fig. 1. (3) 1859. Rhynchonella, Saltbr. Mui'chison's Siluria, p. 544, pi. xxii, fig. 10. (1) 1859. Camartlla, Billings. Canadian Natui-alist and Geologist, vol. iv, pp. 301, 302, 445, figs. 23, 24. (3) 1860. RhynchoneUa, Lindstrom. Gotland's Brachiopoden, p. 366. (1) 1861. Ca»nareZ/a, Billings. Geology of Vermont, vol. ii, p. 949, fig. 353. (1) 1861. Camarella, Billikos. Palaeozoic Fossils, vol. i, p. 10, fig. 13. (2) 1862. Camarella, Billings. Palaeozoic Fossils, vol. i, p. 148, figs. 128, o, 6. (1) 1863. Camarella, Billings. Geology of Canada, p. 121, figs. 52, 53; p. 143, figs. 77, 78; p. J68, fig. 154 ; p. 284, fig. 290. (3) 1863. Pentamerus, Billings. Geology of Canada, p. 957, fig. 453. (3) 1865. Brachymerus, Shalbb. Bull. Mus. Comparative Zoology, No. 4, p. 69. (I) 1865. Camarella, Billings. Paljeozoic Fossils, vol. i, pp. 219, 304, fig. 295 ; p. 305, fig. 297. (1) 1866. Camarella, Billings. Catalogue Silurian Fossils of Anticosti, p. 45. (3) 1867. Ana-ttrophia, Hall. Twentieth Rept. N. Y. State Cab. Nat. Hist., p. 163. (3) 1867. Anaslruphia, Hall. Paleontology of N. Y., vol. iv, p. 374. (3) 1869. Rhynchonella, Davidson. British Silurian Brachiopoda, p. 178, pi. xxii, figs. 24-27. (3) 1879. Anastrophia, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p. 168, pi. xxvi, figs. 41-49. (3) 1882. Anastrophia, Hall. Eleventh Rept. State Geologist of Indiana, p. 311, pi. xxvi, figs. 41-49. (2) 1883. Rhynchonella, Davidson. British Silurian Brachiopoda, Suppl.,p. 201, pi. xi, figs. 26a-d. (1) 1883. Stricklandinia f, Davidson. British Silurian Brachiopoda, Suppl., p. 166, pi. ix, figs. 27-29. (1) 1886. Camartlla, Walcott. Bull. D. S. Geol. Survey, No. 30, p. 122, pi. vii, fig. 8. (1) 1889. CawareWa?, Walcott. Proc. U. S. National Museum, vol. xii, p. 36. (3) 1889. Anastrophia, Bbkchbb and Clarke. Memoii-s N. Y. State Museum, p. 32, pi. iii, figs. 14-16. (3) 1889. Anastrophia, Nettblboth. Kentucky Fossil Shells, p. 47, pi. xxxii, figs. 17-20. (1) 1890. Camarellat, Walcott. Tenth Ann. Rept. Director U. S. Geological Survey, p. 614, pi. Ixxii, figs. 4a-d. CAMARELLA, Billings. 1859. PLATE LXn. The name Camarella was originally applied to subtrihedral biconvex shells with low median fold and sinus ; having, in effect, a rhynchonelloid exterior. The first species of the genus cited by its author, and that which will be taken as representing the typical structure of the group, is Camarella Volborthi, Billings, 220 PALEONTOLOGY OF NEW YORK. ' from the Blivck River limestone of the Ottawa river ; a very similar shell is the C. Panderi, described at the same time from the same locality ; indeed, there may be reason to doubt if there is a valid specific difference in these shells, as both the Canadian specimens and examples from the Trenton limestone of New York (Jacksonburg), afford a series passing from the typical plicated form of one to the non-plicated form of the other. Camarella Volborthi hits full, convex valves, which are smooth about the um- bonal region, but anteriorly develop a few low plications which are rather the more conspicuous on the median fold and sinus, and the fold, sinus and plica- tions are clearly developed on the often abrupt anterior slope of the valves. The pedicle-valve is the more convex up to maturity, but thereafter the brachial valve becomes the deeper. The beak of the pedicle-valve is erect or slightly incurved and beneath it lies a triangular delthyrium which, so far as observed, shows, neither in this species nor in C. Panderi, any evidence of del- tidial plates. The cardinal slopes are abrupt and oblique, and no cardinal area is developed on either valve. On the interior are dental lamellae which con- verge, and uniting, are supported by a short median septum, forming thus a well-defined spondylium like that of Syntrophia. In the brachial valve the hinge-structure is similar to that of Camarotcechia, the crural plates converging and forming a short, very small median cavity, which is supported by a long septum. The crura are short and the lateral divisions of the hinge-plate small. No cardinal process exists. The internal structure of Camarella is, thus, not unlike that of Syntrophia, notwithstanding the wide difference of exterior. Many American species have been referred to this genus, but, from present knowledge it would seem to be quite restricted in range and specific representa- tion. Apparently it does not pass beyond the faunas of the Lower Silurian, and it is probable that most of the species referred to the genus by Mr. Billings will prove to have been accurately placed, though in regard to some of them, their rarity and unfavorable preservation make it impossible to be positive. The species Camarella ? antiquata, Billings, from the early primordial faunas, may or may not belong here ; we know it only from the figures of the exterior BRACHIOPODA. 221 given by Billings and Walcott, and these afford no indication of its generic character except that it has a plicated rhynchonelloid exterior. Mr. Walcott's species, C. minor* from the Olenellus zone, at Stissing Mountain, Duchess county, N. Y., is a smooth, biconvex species, and the figures of internal casts given by this author indicate that the pedicle-valve possessed a small spondylium beneath the beak, resting upon the botton of the valve, the plates bounding it being produced about and just within the cardinal margins. The brachial valve appears to be without a median septum or spon- dylium, but may have had a narrow hinge-plate. Mr. Walcott states that the casts studied by him are imperfect and the generic reference only provisional. With Camarella should probably be placed Davidson's Stricklandinia ? Balcletchiensis,f a rather large rhynchonelliform shell with a short spondylium in the pedicle-valve, and without cardinal area. PARASTROPHIA, gen. nov. PLATE LXin. Among the species which have been currently referred to Camarella are the well-known Atrypa hemiplicata. Hall, of the Trenton fauna, and the Pentamerus reversiis,X Billings, of the Anticosti group. These are shells of considerable size. The inequality of the valves, which becomes apparent in old shells of Camarella Volborthi, is here carried to a greater extreme, becomes developed in immature growth-stages, and in the mature individual the brachial valve is much the more convex, its umbo and beak projecting conspicuously beyond that of the pedicle-valve. These shells have essentially lost their rhynchonelloid expres- sion, being broad and transversely oval in outline, while the median fold and sinus are retained in their normal relations. The surface bears low, rounded plications which are stronger on the fold and sinus, but are also apparent on the lateral slopes near the margins of the valves. Over the median and um- bonal portions of the valves they are obsolescent. The viardinal margin is moderately long and nearly straight, but there is no evidence of a cardinal area on either valve. » Tenth Ann. Rept. Director U. 8. Geolo^cal Survey, p. 614, pi. Ixxii, figs. 4 a-d. 1890. t See Davidso.v, Silurian Brachiopoda, Suppl., p. 166, pi. ix, figs. 27-29. \ The latter has also been lefen-ed by difteient writers to Anastrophia and Tkiplbcia. 222 PALEONTOLOGY OF NEW YORK. In the pedicle-valve the delthyrium is broadly triangular and is usually filled, partially or wholly, by the beak of the opposite valve. On the interior the dental lamellsB make a strong spondylium which reaches almost to the bottom of the valve, being supported by a very low median septum extending nearly one-half the length of the shell. In the brachial valve there are two vertical crural plates not connected by a cardinal process. These are slightly convex on their inner surfaces and at their point of greatest convexity they unite with two longitudinal and gradually convergent lamellae, which form a spondylium narrower than that of the oppo- site valve, and supported by a very low median septum somewhat longer than that of the pedicle-valve. In a species from the Hudson River group, of Wilmington, Illinois, which has currently passed under the name of Camarella hemiplicata* this median septum is usually absent, the plates of the spondylium resting on the bottom of the valve, but in Atrypa hemiplicata and Pentamerus re- versus the small septum is always present. To such forms it is proposed to apply the term Parastrophia, assuming the Atrypa hemiplicata. Hall, as the typical species. This type of structure is continued upward into the faunas of the Niagara group, and in the dolomites of southern Wisconsin occur a number of interest- ing species, our knowledge of which has been derived from the elaborate col- lections made in that region by Thomas A. Greene, Esq., of Milwaukee. Here are at least three species which are new to science, .all of them being preserved as most instructive internal casts. These are described in the Supplement to this Volume as Parastrophia Greenii, P. latiplicata and P. multiplicata, figures of all being given upon the accompanying plates. Among these shells there are no material variations except such as have already been noticed among the earlier species ; for example, the spondylium of the more convex or brachial valve may be supported by a low median sep- tum for its entire length (P. Greenii), or for a portion of its length may rest upon * ThiB form is mnuh less extended than Atrypa liemiplicata. Hall ; its plications ai-e larger, sbai-per and fewer in number, and distinctly marginal. It is a shell quite different from the Trenton species, and may be termed Parastrophia divergent. BRACHIOPODA. 223 the inner surface of the valve (P. latiplicata, P. multiplicata). This feature seems to some extent subject to variation within specific limits; that is, being more or less of an individual peculiarity. The brachial valve of P. latiplicata and P. multiplicata shows four distinct ovate muscular scars about the anterior prolongation of the median septum, and these are of quite the same character as those in the corresponding valve of Anastrophia. Indeed, in all of these species the interior structure does not materially differ from that of Anastrophia, though, being a thin-shelled group, the muscular impressions are not as clearly developed. In exterior characters, however, the differences are more significant. To the six American species which are above referred to Parastrophia, are probably to be added the Rhynchonella Scotica, Davidson, from the Llandeilo of Ayrshire,* and the Pentamerus {Alrypa) rotundatus, Sowerby, from the Wenlock of Wenlock Edge.f It is probable that upon a shell of similar structure to Parastrophia, Gagel has recently based his proposed genus Branconia, B. borussica, from the Lower Silurian diluvial boulders in Ostpreussen (Die Brachiopoden der cambrischen und silurischen Geschiebe im Diluvium der Provinzen Ost- and Westpreussen : Beitriige zur Naturkunde Preussens herausgegeben von der Physikalisch- Oekonomischen Gesellschaft zu Konigsberg, p. 62, pi. iv, fig. 12. 1890). From the description and figures of the exterior of a single specimen it appears to be a trihedral shell of rhynchonelloid aspect, but with a median septum in each valve. What the inner relations of these septa were, or any other interior characters of the shell, is not made known. It seems very doubtful if the author is correct in regarding the more convex valve as the ventral, and the shallow valve as the dorsal, but it will be impossible to pass judgment on the value of the genus as now defined. So early a representative of this structure should receive further elucidation. * Davidson, Silurian Brachi()po>8equently regarded by that author as a synonym for P. Knighti (Silurian System, p. 615, 1839), and the name has consequently fallen Into disuse. BRACHIOPODA. 237 term, is the Pmtamerus lavis, a shell with a smooth exterior, and of which Mr. Davidson remarks : * " It is admitted now by palaeontologists that P. Icevis, Sow., is the young of P. oblongtis; and if it were necessary to strictly adhere to rules of priority, James Sowerby's name, published in August, 1813, would perhaps require [have] to be adopted in preference to that of oblongus, given to the adult shell by Mr. J. de C. Sowerby in 1839; but, when we read over Mr. James Sowerby's unsatisfactory description, and examine his small, very incomplete figure, it seems preferable to preserve for this shell the now generally adopted and well- known designation of oblongus." Pentamerns oblongtis is a species of very variable contour, with a smooth exterior, sometimes bearing a few broad and obscure radiating undulations, transverse or elongate-oval in outline ; the valves are usually shallow, but in some of the many variations of the species attain a considerable depth. Though there is no median fold and sinus, a median anterior prolongation of the valves, defined by two convergent lateral furrows, is a normal character, as shown in the original figures given in the "Silurian System" (plate xix, fig. 10). This gives the shell a trilobed character which is carried to an extreme devel- opment in the series of shells connecting the typical form with those consti- tuting the variety cylindricus, Hall. In American faunas, where this species attains a great development in individuals, its numerous variations in contour and general expression often possess a definite local value. The shell abound- ing in the Pentamerus limestone of the Clinton group of New York is, as a rule, of comparatively small size, broadly oval or obovate, rarely elongate in outline ; though the trilobation of the exterior is always apparent, it is seldom conspicuously defined. Rarely the shell is narrowed across the umbones, and subtriangular in outline. (See Plate LXVII, fig. 2.) In New York this species is not known outside of the Clinton fauna, but passing westward, it abounds in the dolomites which bear a Niagara fauna in the states of Ohio, Indiana, Illinois, Wisconsin and Iowa. At Yellow Springs, Ohio, the prevalent form is a large, elongate, usually strongly trilobed shell, with narrow beaks and long, oblique cardinal slopes. * Silurian Brachiopoda, p. 153. 238 PALEONTOLOGY OF NEW YORK. The same form of shell occurs rarely in Wisconsin (Door county), and has been described by McCuesnky as P. bisintuittis* a name which may serve a useful pur- pose as a varietal designation. About Richmond, Indiana, a broader, more ovate shell predominates, which does not widely differ from the characteristic form of the Clinton fauna of New York. At Utica, in the same State, and in the vicinity of Louisville, the narrow elongate shell, P. oblongus, var. cylindricus, abounds ; it is usually deep-valved and distinctly trilobed. Among the shells occurring in the dolomites of Wisconsin there is a great var- iation in form, with a tendency to increasing depth of valves, but these variations are less extreme, and their geographic value has not been determined. Thus also with the representatives of the species in the dolomites of Iowa (Earlville and elsewhere). In the siliceous beds of the Niagara group in the latter State (Jones county), there is a small, ovate, often elongate variety, with the triloba- tion rather faintly marked, and a quite distinct form in the rusty chert of the same county, the latter a subquadrate shell, very broad across the cardinal region, with nearly straight, parallel lateral margins, very full and prominent umbo, distinctly trilobate surface, the median lobe being divided by a linear axial groove on both valves. This is so well defined a shell and so distinctively local in its value that it may receive the varietal designation subredus. With all these variations in exterior there are some slight differences in the interior structure. A concave deltidium is sometimes retained, and a faint Fig. 1C9. FlO. 170. Fic. 171. Flu. 172. Fig. 169. /•en0(la, Suppl., p. 164, pi. ix, fig.s. 2.'), a. (4) 1884. ffj/pidtt/o, Walcott. Monogr. U. 8. Geol. Survey, vol. viii, p. 159-161, pi. iii, figs. 4, 7; pi. xiv, fig. 15 ; pi. XV, fig. 5. (1) 1887. Antirhynchonella, CRhlkht. Fischer's Manuel de Conehyliologie, p. 1311. (3) 1887. Sitberella, CEhlkht. Fischei-'s Manuel de Conehyliologie, p. 1311. (1) 1889. Pentamerus, Nbttblkoth. Kentucky Fossil Shells, p. 64, pi. xxiii, figs. 12-14. (3) 1889. PeTitamerut, Nkttblroth. Kentucky Fossil Shells, i)p. 59, 63, pi. xxvii, figs. 26-27; pi. xxxiii, figs. 25-29, 31-33. (1) 1892. PentoJuerits, R. Ethkridgb, Jr. PentameridsB of New South Wales ; Records Geol. Survey N. S. W., vol. iii, pt. 3, p. 52, pi. xi, fifjs. 5-9. (4) 1892. Pentamerus, Whitbavbs. Contributions to Canadian Palteontology, vol. i, p. 290. The elong. 37, pi. iii, fig. 24. 1848. Spirifer, db Vernkuil. Bull. Soc. Geol. France, second ser., vol. v, p. 347. 1852. Spirifer, Hall. Pulfeontology of N. Y., vol. ii, p. 66, pi. xxii, fig. 3. 1859. Pentamirm, Palter. Murchison's Siluria, second ed., pp. 100, 230, figs. 1, 3. 1859. Striiklandia, Billikgs. Canadian Naturalist and Geologist, vol. iv, p. 132-135. 1861. Stricklandia, Billimgs. Canadian Journal, vol. vi, p. 265. 1862. Stricklandia, Billings. Palseozoic Fossils, vol. i, p. 84. 1863. Stricklandia, Billi.nos. Proc. Portland Soc. Nat. Hist., vol. i, p. 114. 1863. Strlcklandinia, Billings. Canadian Naturalist and Geologist, vol. viii, p. 370. 1866. Stricklandinia, Billings. Catalogue Silurian Fossils of Anticosti, p. 45. 1867. Stricklandinia, Hall. Twentieth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 160. 1867. Stricklandinia, Hall. Pala;ontology of N. Y., vol. iv, p. 369. 1867. Stricklandinia, Davidson. British Silurian Brachiopoda, pp. 157-163, pi. xix,fig8. 13-23; pi. xx, figs. 1-13. 1868. Stricklandinia, Billings. Geological Magazine, vol. v, p. 59, pi. iv. 1870. Stricklandinia, Meek and Wobthbs. Proc. Acad. Nat. Sci. Philadelphia, vol. xiv, second ser., p. 37. 1874. Stricklandinia, Billings. Palasozoic Fossils, vol. ii, pp. 78, 81, 83, fig. 49; pp. 84-89, pi. vi, figs. 1,2; pi. vii, figs. 1, 4. 1875. Stricklandinia, Meek and Worthen. Geol. Survey of Illinois, vol. vi, p. 502, pi. xxiv, fig. 5. 1876. Stricklandinia, White Proc. Acad. Nat. Sci. Philadelphia, vol. vi, third ser., p. 30. 1877. Stricklandinia, Whitfield. Annual Rept. Geol. Survey of Wisconsin, p. 81. 1880. Stricklandinia, Dawson. Canadian Naturalist and Geologist, vol. ix, second ser., p. 341. 250 PALAEONTOLOGY OF NEW YORK. 1880. Stricklandinia, Whitk. Pioc. U. 8. National Museum, \i. 48. 1889. Stricklandinia, Whitkikld. Geology of Wisconsin, vol. iv, p. 31S, pi. xxiii, fijfs. 3-5. 1883. Stricklandinia, Davidson. British Silurian Brachiopoda, Suppl., pp. 164, 166, pi. ix, &ga. 1-5. 1884. Stricklandinia, Kiksow. Ueber Sihir. un conjoined. The whole of the anterior portion of the brachidium is inclined gently upward toward the cavity of -the opposite valve. The muscular impressions occupy an elongate area below the hinge-plate, and are divided by a median ridge, but are only obscurely divisible into their elementary scars. The lateral portions of this valve frequently bear a series of vascular sinuses in the pallial region. Surface smooth or with concentric lines crowded near the margins of the valves. Shell-substance punctate. Type, Rhynchmella glans-fagea, Hall. Upper Helderberg group. Observations. The t3rpe of external form and internal structure exemplified by this species is probably also represented by the C. alveata, Hall (= C. Hecate, BRACHIOPODA. 269 Billings), of the same fauna, and is carried forward from the Schoharie grit and Corniferous limestone into the succeeding fauna of the Hamilton group (C. impressa and C. Glaucia, Hall). All these typical forms of Centronella were preceded in the fauna of the lower Oriskany of eastern New York by a large species, the earliest known possessor of the characteristic naviculoid form and smooth exterior of Centro- nella glans-fagea. The form of the brachidium of this shell (which has not hitherto been described*), has not been determined, but there is every reason to infer that it differs in no essential feature from that of Centronella, for the reason, as already observed, that variation in these shells during the Devonian was virtually restricted to exterior characters and did not affect the conforma- tion of the brachial supports. The hinge-plate of this shell, however, is notably diflferent from that of any of its allies ; it is elongate-triangular, continuous between the crural bases, and bears a median vertical crest, or cardinal process, which begins at the apex, rises rapidly in height, and extends for fully one-half the length of the plate on its upper edge, but at its base is shortened and con- stricted, forming a projecting cardinal spur. Fio. 181. Fig. 182. Fig. 183. OrUkania naricella, sp. nor. Fig. 181. .\ cardinal view; ahonring the hinge-plate ami the elevation of the narrow median crest or cardinal pro- cess. The specimen also retains the leeth of the pedicle-valve and a iiortion of the dental lamellse, though the latter are broken near the surface of the valve. Fig. 182. An enlargement of the hinge-plate; showing the crural lobes and the extent of the cardinal process. Fig 183. A proOle of the same specimen; showing the thicltnesa of the plate and the uncinate form of the cardinal process. X 3. (O.) Such an extravagant modification of the normal form of the hinge-plate in Renssel/Eria and Centronella is the more remarkable on account of its early age, as this shell antedates the appearance of the typical Devonian species with divided hinge-plate and without cardinal process, and it is proposed to distinguish * " Centronella, of the type of C. glans-fagea but of great size." Bbbcbeh and Clarkk. Notice of a new lower Oriskany fauna in Columbia county, New York ; Amer. Journal of Science, vol. xliv, p. 414. 1892. 270 PALJEONTOLOGY OF NEW YORK. this type of structure by the name Oriskania. The typical form is described in the Supplement to this Volume as Oriskania navicella. It is a fact of much interest that the centronellid type, with naviculoid shell, divided hinge-plate and simple brachidium, is reproduced in the Alpine Triassic faunas, in the genus (?) Nucleatula, Zugmayer,* a shell which evinces only an immaterial variation in the narrowness and fimbriation of the anterior plate of the brachidium. Before considering the later modifications of the centronellid type, we may refer to another form of exterior expression assumed by the same type. A small, hitherto unnoticed species occurring in the Upper Helderberg of the Province of Ontario, possesses a smooth exterior, terebratuliform outline, nar- row at the umbones and broad in the pallial region, with biconvex valves. While the detailed structure of the hinge-plate is yet unknown, the brachidium is similar to that of Renssel^ria and Centronella ; the anterior plate broader and less attenuate than in Renssel^ria and without its central, rod-like poste- rior extension, and also lacks the median ridge or thickening along the sym- physis of the lateral elements, which exists in Centronella. The form of the shell scarcely suggests the naviculoid contour of true Centronella, while it at once brings to mind some of the biconvex species that have heretofore been FIG. 18i. FlO, 185. FIO. 186. Seknella graeUU, gp. nov. Fig. 184. Outline profllo of conjoined ralves. Fig. 188. Prcparntion BliowinK tlie form of tlie loop. Fig. 186. An oblique view; showing Ihe upward curvature of the anterior plate. X 3. (0.) classed with that genus, e. g., Centronella Julia. From such of these whose inte- riors are known it differs notably, and it so evidently indicates a distinct stadium *See BiTTNKK, Bi-acbioiM>den der Alpinen Ti-ias; Abhandl. der K.-k. Qeol. Reicbstanst., vol. xiv, p. 208. 1890. BRACHIOPODA. 271 or departure in the variations of this type of structure as to require a separate designation. The name Selenella is therefore introduced for the subgeneric type, its representative species being Selenella gracilis, sp. nov. As already observed, this shell presents the first combination of the smooth, biconvex valves with an unmodified RENSSELiERiA-CENTRONELLA brachidium. From our experience such a simple combination could not be of long contin- uance, and thus far we have no evidence of its subsequent appearance. Biconvex and smooth-valved centronellids do occur, however, at a much later period and after the close of the Devonian, but these have undergone a very material modification in the form of the brachidium. In CentroneUa Julia, A. Winchell, one such small, smooth species, from the Marshall group of Michigan, FIO. 187. Fia. 188. Romingerina Julia, Winchell. Fig. 187. A restoration of the loop; ahowint; the extent or the meilian pinte. rig. 188. A profile view; ebowing the elevation ol this plate, the double currature of its npper margin and its fim- briated edge. X4. (A. Winchell.) the median ridge on the anterior plate of the brachidium is elevated into a conspicuous vertical lamella, extended both anteriorly and posteriorly, being in fact a double plate produced by the abrupt deflection of each lateral branch of the brachidium near the median line; union taking place along the upper edge, which almost reaches the inner surface of the pedicle-valve. Professor Alexander Winchell, who was the first to demonstrate this structure, adds in regard to this feature : * * The little epecies fi-om the Chemnnjf sandstones at Rnshford, N. Y., which has been identified by WaLiAUB as CentroneUa Julia (Bull. U. S. Oeol. Survey, No. 41, p. 56. 1887), has the brachidium of similar structure though with a less ante-postei-ior extension of the verlical plate. 272 PALEONTOLOGY OF NEW YORK. " The upper edge where viewed fromthe side, is flatly roof-shaped, while the lower edge describes two convexities, the greater anterior, leaving a notch between them. The surHices of the loop and median plate are covered with minute, obliquely conical pustules, ii\ some cases seeming to become spinulous."* Forms with this characteristic modification of the loop may be designated by the term RoMiNGERiNA.f After the disappearance of the Palaeozoic faunas, we again find in the Alpine Trias (Hallstiitter-kalk) smooth, biconvex centronellids, less complicated in the structure of the brachidium than Romingerina, even having the brachial sup- ports smaller and more delicate, if not more simple in plan, than in Selenella. These shells have been described by Bittner {loc. cit., p. 206. 1890) under the generic term Jdvavella. Their bnichidia are very short, the lateral branches but slightly expanded anteriorly and abruptly turned into a vertical plane. We may now turn to the consideration of the plicated centronellids which have already been closely investigated by (Ehlert, and have received attention from Waagen, Derby and Davidson. This discussion would with propriety form a continuation of the observations already made upon the genus Rens- SELiERiA, for it is the plicated and lineate shells of that genus which represent the earliest appearance of the CENTRONELLA-type. The lower Devonian species, from the west of France, in which Dr. CEhlert has determined the existence of a centronellid brachidium, are all biconvex or subplano-convex species; Terebratula Guerangeri, de Verneuil, is covered with strong rounded plications, Centronella Gaudryi, CEhlert, with numerous fine plications, while on C. Bergeroni, CEhlert, there are a few coarse angular ribs. All have a decided external resemblance to certain spire-bearing forms of the genera Rhyncmospira, Tre- MAT08PIRA and ZvGOSPiRA. The brachidium has been isolated in none of these, but sections demonstrate that this structure in all these forms is similar to that * Proc. Acad. Nat. Sci. Philadelphia, p. 405. 1662. t Dr. Carl Rominobr, to whom this genus is dedicated, was the fii-st American investig-ator who suc- ceeded in pi-oducing satisfactory translucent pi-epai-alions of the fossil brachiojwds with calcified brachidia. Many of the determinations published in the Reports on the New York State Caliinet from 1861-67, and in Volume IV of the Paljeontology of New York, as there recognized, wei-e based upon his preparations. BRACHIOPODA. 273 of Cmtronella glans-fagea, though having the anterior plate much smaller. Cen- tronella Guerangeri is known to possess a perforated hinge-plate, though in the other species this plate appears to have been divided. Fio. 189. Trigtria Chterangeri, de Verneall. The interior of the brachial valve; showing the perforated hinge-plate and the muscular scars. (CEhlert.) (Ehlert draws attention to the fact that Bayle, in 1875,* applied the name Trigeria to two lower Devonian species, the first, the Terebratula Adrieni, de Verneuil, which was already the type of the genus Retzia, King; the second, Terebratula Guerangeri. This name, unfortunately, was not defined, but as a designation is required for these plicated centronellids, it is now proposed to make use of the term introduced by this French author, basing its value upon his second species. Trigeria is represented in the Oriskany sandstone at Cumberland, Maryland, by a species very similar to T. Gaudryi; indeed, upon careful comparison with Dr. Qi^HLERx's description and figures there seems no good basis of distinction between the two forms, and the American fossil will be thus referred awaiting further evidence. It is quite probable that the species described by Billings as Rensselaria Portlandica,-\ from the Lower Helderberg fauna of Square Lake, Maine, is another representative of the same type of structure.:}: * Explication de la Carte Geologique de France, Atlas, pi. xiii, figs. 5-12. t Proceedings of the Portland Society of Natural History, vol. i, p. 115, plate, fig. 12. 1862. X For the opportnnity of examining the original specimens of the species we are indebted to Professor B. K. Embrsox, of Amherst College. 274 PALEONTOLOGY OF NEW YORK. Derby's Cenironella ? Margarida, from the lower or middle Devonian of Matto Grosso, Brazil, is a shell somewhat different from the foregoing species in external expression, its size being smaller and its habit more retziiform. Its author has compared it to the Retzia Wardiana, Hartt and Rathbun, of the Erere fauna on the A.mazonas, a species which is suggestive of the Rhynchospira lepida, Hall, of the Hamilton fauna of New York. Dr. Derby has given a very complete representation of the brachidium of the species, which arises from a divided hinge-plate, bears the long, anterior plate characteristic of Renssel^eria, and lacks any evidence of the posterior median extension or of a vertical median plate. In the species which has been described as Rhynchospira lepida, of the Hamilton shales of New York, and in the Centronella virgo {Terebratula virgo, Phillips), from the middle Devonian of Torquay,* both very closely allied in the character of the plicated exterior, there exists the same form of brachidium. This combination of external and internal characters is thus a variant from that of Centronella or Trigeria, but until our knowledge of these small shells is further advanced, the species may be provisionally associated with Trigeria. ■ Fig. 190. FIO. 191. FlO. 192. Notothi/ri» subcacicularU, Davidson. Fig. 190. A dorsal vlewof the exterior. Fig. 191. A profllo of the same shell. Fig. 192. The interior of the brachial valve; showing the perforated binge-plate and the lateral lamellis of the loop. (Waagen.) Reference has already been made to the fact that Waagen introduced the name NoTOTHYRisf for a group of small, coarsely plicated, biconvex species * See preparations of the brachidium of this plii».ted species made by the Rev. Norman Glass, and given by Davidsoh, Devonian Brachiopoda, SuppI , p. 14, pi. i, tigs. 7-9. 1882. t Productus-limestone Fossils; Brachiopoda, p. 375. 1882. BRACHIOPODA. 275 whose internal structure is but partially known, but which seem to indicate a certain relationship to the centronellids. This author states that all his prepara- tions of the brachidiuin showed the lateral branches to be disconnected, but he believes this to be probably due to imperfect preservation. All of the eight described species of this genus {Terebratula suhvescicularis, Davidson, type) are from the Upper Carboniferous of India, and similar forms have not been iden- tified with certainty in other countries. The Devonian species Notothyris? Smithi, Derby, has a perforated hinge-plate and a brachidium very similar in form to that of Centronella, but instead of the curved anterior plate, it has a simple cross-bar connecting the lateral branches. In Dielasma and other tere- bratuloids we know that the reflected or ascending branches are frequently lost, and it is more than likely that the typical Notothyres possessed an anterior cross-bar as in the Devonian species. Genus SCAPHIOCGELIA, Whitfield. 1891. 1891. Scaphiocctiia, Whitfield. Trans. American Inst. Mining Engineers, vol. xix, p. 106, figs. 1-4. "A terebratuloid, brachiopodous shell*, having a strongly convex ventral valve, and a longitudinally and angularly sulcated dorsal valve; both of which are strongly plicated. Internally the ventral valve has a strong, deep, triangular byssal opening and muscular seat, and the dorsal has strong crural processes ; but the loop or calcified appendages are un- known. Shell structure strongly fibrous, without any puncture under a hand-magnifier." Type, Scaphioccdia Boliviensis, Whitfield. Devonian. Observations. As suggested by Mr. Whitfield, this great shell has, the appearance of a gigantic plicated Centronella, and in the absence of any defi- nite knowledge of its internal structure, may provisionally be regarded as allied to that genus and those plicated centronelloids which have been herein designated by the term Trigeria. The only species known, S. Boliviensis, is stated to sometimes exceed three and one-half inches in length. It was found by Mr. A. F. Wendt in the vicinity of Sucre or Quechista, Bolivia, in a sandy, 276 PALEONTOLOGY OF NEW YORK. ferruginous limestone, associated, according to Whitfield, with Spirifer Quichua and Terebratula Antisiensis, d'Orbigny. Fia 194. FlO. 199. FiO. 198. Scaphioealia BolMentU, Whitdeld figs. 19S-196. Views of two indirldaals, showing the external characters or the species. , (Whitfield.) BRACHIOPODA. 277 Genus MEGALANTERIS, Suess. 1855. PLATE LXXVII. 1830. Terebtatvla, de VBRMEniL. Bull. Src. G6ol.'de France, 2 ser., vol. vii, p. 17.5, pi. iv, fig. 2. 1855. Meganteris, Sdess. Uebei- Meganteiis j Sitzungsber. (ier Kais. Acad, der Wissensch. zu Wien. 1856. Meganteris, Scass. Classification der Brachiopoden, von Th. Davidson, p. 43, pi. ii, fig. 18. 1857. Megantmx, Hai,i,. Tenth Ann. Kept N. Y. State Cab. Nat. Hist., p. 101. 1859. Hensselceria, Hall. Palieontology of New York, vol. iii, p. 458, pi. cvi, fig. 2 a-l. 1861. Rtnsselceria, McChesney. Descr. New Fossils from Palaeozoic Rocks of West. States, p. 85. 1867. HensstlcBria, McChesnet. Trans. Chicago Acad. Sciences, vol. i, p. 38, pi. vii, figs. 2a-c. 1868. Reiusselwr'm, Mkek and 'WoRTHKif. Geological Survey of Illinois, vol. iii, p. 401, pi. viii, figs. 4 a, 6. 1871. Meganteris, Quknstedt. Petrefactenkunde Deutschlands ; Brachiopoden, p. 344, pi. xlvii, figs. 21. 22. 1876. Meganteris, F. Roemer. Lethsa Palseozoica, pi. xxiii, fig. 6. 1887. Megalanteris, CEhlbkt. Fischer's Manuel de Conchyliologie, p. 1319. 1891. Newben-iaf, Hall. Tenth Rept. N. Y. State Geologist, p. 95. Though this generic division is of long standing, its value has been regarded as somewhat uncertain. Shells agreeing with the type of Megalanteris in external form and in the conformation of the interior of the valves are not of uncommon occurrence ; but these are so closely allied to Renssel^ria in exter- nal form, that the possession by them of a brachidiura widely dissimilar to the corresponding apparatus of that genus seems a priori improbable. The ideal- ized restoration of this structure, given by Suess, has not been confirmed by later investigations, but neither has it been disproved ; and we are therefore justified in assuming its accuracy. The American species, M. ovalis, Hall, is not favorably preserved for the retention of those parts. To apprehend the author's conception of this genus, a translation of the diagnosis inserted in his edition of Davidson's " Classification of the Brachiopoda " is here introduced : " Shell, in the only species hitherto known, large, smooth, equally biconvex, of very variable, elongate-hexagonal to transversely oval outline, and with punctated shell structure. Beak depressed, with a small opening for the pedicle- muscle, reaching to the somewhat incurved umbo of the pedicle-valve and limited on both sides by a depressed deltidium. Hinge apparatus strong, similar to that of other terebratuloids. Below the beak of the dorsal valve, the central part of the hinge-plate is swollen into a callous uncinate process, which is subcubical, and on its surface bears two small V-shaped ridges for the 278 PALjEONTOLOGY of new YORK. attachment of the cardinal muscles ; on both sides are two flattened areas, presumptively places of attachment for the inner, dorsal branches of the FlO. 197. FlO. 198. Mtgakmttrit Archiaci, de Verneull. Fige. 197, 198. Views of the exterior of the species. (DE Veenecil.) pedicle; at its base it is excavated and funnel-shaped. Between the sides of these swellings and the sockets, lie the points of attachment of the brachial apparatus. The crura are produced into two broad, straight rods, extending almost to the middle of the shell, curved somewhat inward, rounded at the ends, and which on the whole, have little similarity to the converging Fia. 199. FlO. too. Mtgalanttrit Archiaci, de Verneail. Figfs. 199, 200. A restoration of the brachial apparatus (SlTBSS.) BRACmOPODA. 279 processes of other Terebratulas. From the upper part of these rods arises the brachial support, consisting of a very slender calc-ribbon, which, somewhat as in Waldheimia, first extends to the vicinity of the anterior margin, then bends abruptly backward, inclining somewhat toward the center of the shell-cavity, and is closed by a short, straight cross-piece, above which the ascending branches project as short points ; this cross-piece and the upper part of the ascending branches lie below the plane of the straight rods. While in the small valve the hinge-muscle and the inner pair of dorsal pedicle-muscles are attached to the callous process, the outer pair of pedicle-muscles appears to have been fastened to the upper portion of the crura. The impressions of the adductors, of which but two are discernible, lie somewhat above the middle of the valve, in two cavities, often very deep, semicircular on their posterior margins, but oblique and shallow in front. no. Ml. FIO. 202. ' Uegatanteiit Archiaei, de Vernouil. Fig. 201. An internal cast of the nmbonal region of the pedicle-valve. (SuBSS.) Fig. 20-2. The interior of the umbonal region of the brachial valve; showing the cardinal process. (De Vebneuil.) " In the large valve the muscular area is close about the umbo, and is similar to that of the terebratuloids ; a middle elongate space corresponds probably to the adductor muscles ; on either side of this, one recognizes the impressions of the diductor muscles, and outside and somewhat behind these, though not always clearly defined, are the areas of insertion of the ventral branches of the pedicle-muscle, which also seems to lie on the inner surface of the dental plates. " On the inner surface of both valves may be distinguished four impressions of trunk-sinuses, from which arise no dichotomous branches as in other tere- bratuloids. The posterior part of the outer pair of these sinuses is in each valve surrounded by the impressions of the genital organs, whose outer portion 280 PALEONTOLOGY OF NEW YORK. is divided by three or four parallel finer vessels, which are given off from the margin of the trunk-sinus at right angles. In the larger valve on the inner side of the outer pair of trunk-sinuses, may be seen fine branches, originating at sharp angles. Further, in this valve may sometimes be seen, between the outer and inner, and also between the two inner trunk-sinuses, two finer radi- ating veins. All these vascular sinuses appear to unite in this valve to form a large lacune surrounding the area of muscular insertion. A ridge-like, elongate callosity crossed by irregular furrows, follows the cardinal margin on the dorsal valve." Type, Terehratula Archiaci, de Verneuil. Observations. Leaving out of consideration for the present the peculiar structure of the br.achidium, we find the other characters of the shell suflBci- ently distinct from those of Renssel^ria and its allies ; and these differential features are found in the general smoothness of the exterior,* the inflexion of the cardinal and lateral margins of the valves, the prominence and sharp delimitation of the diductor scars of the pedicle-valve, and the subcylindrical elevation of the hinge-plate into a veritable cardinal process, in which all traces of supporting lamellae are lost, and whose posterior face is grooved and striated by the insertion of the muscles. This latter feature is unusual in the palaeozoic terebratuloids, and is at once suggestive of the structure in the large and heavy rhynchonelloids (Plethorhynchos), so that it proves a distinctive character of importance. An excellent representative of this type of structure is the American Oris- kany species, originally described! as Meganteris ovalis. Hall, but which has been subsequently and currently referred to RensseljERIA. In the original description the similarity of the internal casts to those of Megalanteris Archiaci was noted. Megalanteris ovalis is not an abundant species in the Oriskany sandstone of New York and Ontario, and is represented in the formations in the vicinity of Jonesboro, Illinois, by a smaller, more elongate form with erect beak, deep cardinal and marginal excavations, the Rensseleria Condoni, of * Internal casts frequently show a minutely ituliate surface about the margins, but this structure prob- ably belongs to the inner lamins of the shell. t Tenth Annual Reprt on the ComUtion of the N. Y. State Cabinet of Natuial History, p. 101. 1857. BRACHIOPODA. 281 McChesney. None of the specimens that have been sectioned retain the bra- chial apparatus. The name Meganteris or Meqalanteris* has been adopted by various writers, sometimes with questionable accuracy. Megalanteris Archiaci, de Verneuil (sp.), the type of the genus, was described from the Devonian beds of Sabero and the mountains of Leon, Spain ; the material upon which Suess founded his determination of the brachidium, seems to have been derived from the lower beds of the Eifel. Quenstedt has also given figures of internal casts of this form from Lahneck. The species Atrypa inornata, d'Orbigny, from the lower Devonian of western France, has been referred to this genus by GEhlert,! but the figures given by him show a want of conformity to the generic characters of Megalanteris, both in the form of the hinge-plate, the muscular impressions and the regularity of the lateral margins. Kayseb has suggested^: the similarity of the Terehratula amygdalina, Goldfuss, to Megalanteris, and (Ehlert, in the work cited, refers d'Orbigny's species, A. amygdala, and the A. Deshayesi, Caillaud, to the same genus, remarking their close similarity to A. inornata. Barrois has also described and figured § A. inornata and A. Deshayesi under the name Megalanteris. It has already been suggested that these European lower Devonian shells represent a type of structure different from that of M. Archiaci, which is hereinbefore designated as Newberria. Mr. Davidson figured, without name, in his British Devonian Brachiopoda (pi. XX, fig. 15), and subsequently (Devonian Supplement, p. 20, pi. iii, fig. 1) as Meganteris ? Vicaryi, the exterior of a large shell from the middle Devonian of Woolborough, England, having a smooth surface and inflected margins, but of its internal characters nothing is known. A median line on the brachial valve indicates the presence of an internal septum. * The latter word, substituting' the feminine for the masculine form of the adjective, was introduced by (Ehlbbt, in 1887. t Annales des Sciences Geologiques, vol. xix, p. 20, pt. ii, figs. 1-10. t Zeitschr. der deutsch. geolog. Gesellsch., vol. xxiii, p. 499. 1871. } Faune du Calcaire d'Erbray, p. 151, pi. x, figs. 5, 6. 1887. 282 PALEONTOLOGY OF NEW YORK. Gbmos STRINGOCEPHALUS, Defrance. 1827. (emend. Sandberger. 1842.) 1837. StrygocephaIu-1, Dbkbancb. Diction. <\ea Sciences Nat., vol. li, p. 102, Atlas pi. Ixxv, fijfs. 1, lo. 1827. Ter^tratnla, Sowbrbt. Mineral Concholoiry. I'l- <1Ixxvi, fig. 1. 1834. IVrebratula, von Buck. Ueber Terebraleln, p. 117. 1839. StrigocepfiaJua, Sowerby. Trims. Geol. Soc. London, vol. v, second ser., pi. Ivi, figs. 10, II. 1840. Strygocephalus, D'AncuiAC and db Vbrmbuil. Trans. Geol. Soc. London, vol. vi, 2 sei-., p. 398. 1841. StrigucepJiatus, Phillips. Palseoz. Foss. Cornwall, Devon and West Somerset, p. 79, fig. 141. 1842. Stringocephalns, Sandbbboer. Leonhard und Broiin's Jahi-buch, p. 386. 18C0. Stringoctphalus, F. Robmek. Beitr. zur Kenntn. des nordw. Harzgeb., p. 24, pi. x, fig. 2. 1862. Vncites, McCoy. British PaliEoz. Foss., p. 380, pi. iiA, fig. 6. 1863. Stringoceplialus, Schsdr. Beschreib. Eifel. Brachioi>oden, p. 196, pi. xxviii, fig. 6 ; pi. xxix, fig. 1; pi. xxxi, fig. 1. Is60. Slrigocephalu8, Kino. Pei-mian Fossils, p. 70, pi. xix, fig. 1. 1863. Stringocephalns, Sbbss. Verb, der zool. bot. Vereins zu Wien, vol. iii. 1855. Stringocephalus, The Sandbbrgers. Vei-st. des rhein. Schicht. Syst. in Nassau, p. 307, pi. xxxi, fig. 4o-d. 1866. Stringoctphalus, Davidsom. Inti eduction Biit. Bracbiopoda, p. 73, pi. vii, fig. 98. 1858. Stringocephalm, 80B8S. Class, der Bracb. von Th. Davidson, p. 62, pi. i, fig. 16. 1864. Stringocephalus, Davidson. Biit. Devon. Biachioiioda, p. II, pi. i, figs. 18-22; pi. ii, figs. 1-11. 1871. Strigocephalus, Qdbnstbdt. Brachiopoden, p. 234, pi. xliii, figs. 58-75 ; pi. xliv, figs. 1-8. 1871. Stringocephalus, Kaysbr. Zeitscbr. der deutsch. geolog. Gesellsch., vol. xxiii, pi. di. 1891. Stringocephalus, Whitbavks. Contrib. Canad. Palaeont., vol. i, No. 5, p. 23.i, pi. xxix, figs. 10, lOo, 11, 11a. Shell varying in outline from transverse to elongate-oval, biconvex; the brachial valve being somewhat the deeper; the greater convexity is in the umbonal region, giving to the brachial valve a high-shouldered appearance. On the pedicle-valve the beak is somewhat narrow, its apex being abruptly attenuate, acute and often greatly incurved. From beneath the beak diverge two sharp ridges extending to the extremities of the hinge and delimiting the broad cardinal excavations which seem to constitute a true cardinal area. The delthyrium is broad and triangular ; in young shells it may be wholly open or incompletely closed by the imperfectly developed deltidial plates, while at maturity it is closed with the exception of a circular foramen, and in old shells the deltidial plates are anchylosed, forming a single plate which becomes incurved, and the foraminal passage is thus obscured, and may take the form of a tube or sheath prolonged into the umbonal cavity. On the interior the teeth are short, free and curved upward at their extrem- ities. In the middle of the valve is a vertical longitudinal septum, which BRACHIOPODA. 283 extends from the beak to near the anterior margin. This septum is short and thick posteriorly, but becomes thinner and higher towards the front, ending abruptly in the pallial region. In the brachial valve the umbo is obtuse. The cardinal area is distinctly developed and divided by a very broad triangular fissure, the covering of which (chilidium) is frequently retained, much modified by the presence of the great Fio. 203. Stringocephalut Bvrtini, Defrance. Doreal views of Iwo tndividaals; ^bowing the differences assamcd in growth by the ambo of the pedicle-valre. (Qdenstedt.) cardinal process. The dental sockets are comparatively shallow. The general form of the hinge-plate is triangular, with its apex anterior ; its central portion is separated from the narrow, blade-shaped lateral divisions and is produced into a great cardinal process, rounded posteriorly, narrow and sharp on its anterior surface, and produced upward and backward into the cavity of the opposite valve. At the edge of the median septum of that valve it bifurcates, sending out a short clavate apophysis on either side of it. The lateral por- tions of the hinge-plate begin at the socket-walls which are high and narrow, extend downward, inward and forward to the anterior extremity of the plate, whence they curve upward into the crura. The crura are long, broadened and curved upward towards their extremities where the primary arms of the bra- chidium arise at a sharp angle. The latter curve backward and outward, and 284 PALEONTOLOGY OF NEW YORK. skirt the inner margins of the valves as a very broad, continuous lamella, which is not reflexed though somewhat curved upward on the anterior margin. no. 2M. Fio. i06. Fig. 205. Stringocephalut llurtini, Derrance. Fig. 2M. Umboual cavity of the podicle-Talve with discrete deltidial plates. FiK. SOS. The internal sheath or projection of the pedicle-passage. tig. 206. The umboDal cavity of a pedicle-valve in which coalescence of the deltidial plates is almost complete. (QUENSTEDT.) From the inner margins of this lamellae, on its exterior and lateral extension, arises a series of linear processes converging toward, and some of them perhaps Fig. 207. Stringocephalm Burtini. Defranoe. A restoration of the interior, showing the internal pedicle-sheath and the strong median septum of the pedicle- valve; the great cardinal process, one of its terminal lobes (e) lying on either side of the septum; the form of the loop with the railial lllaments extending from the anterior lamella (d) to the ontra. At (a) is the insertion of the didactor muscle, at (6) that of the adductor. (Hoebnes ) reaching the crura. A low, thick median septum extends for about half the length of the valve. The muscular impressions on both valves are exceedingly obscure, and have never been fully described or illustrated. Surface smooth, with fine concentric growth-lines ; sometimes a low median sinus exists on both valves near the margin. BRACHIOPODA. 285 Shell-substance impunctate externally, but the inner laminae are sparsely perforated. Type, Stringocephaltis Burtini, Defrance. Middle Devonian. Observations. This old and well known genus has been discussed by many wi iters, but to King, Suess and Qoenstedt our knowledge of its internal structure is especially due. Its characters are extravagant and its com- position is peculiar and unique, the genus standing quite apart from other tere- bratuloids. Whence its origin is still a mystery. The duration of the type was brief, though its development was abundant and characterized a distinct horizon of the middle Devonian, the " Stringocephalus beds." Its presence, however, has not been widely known outside of Germany and England, and hence its recent discovery by Whiteaves in the Mackenzie River Basin of British North America, is of much interest. Here it is associated with various middle Devonian species. Authors are pretty generally agreed that the different specific designations which have been suggested for slight variations in form, etc., are based upon minor characters, insufficient to separate them from the type-species, S. Burtini, The S. Bohemicus, Barrande,* is a much earlier form (F.^,) whose generic char- acters are entirely uncertain. * SystJme Silurien, vol. v, p. 218, pi. 83, Iv. 286 PALEONTOLOGY OF NEW YORK. Gbnus crypt ONEL la, Hall. 1861. PLATE LXXX. 1860. Tmibrotula, Hall. Thirteenth Ann. Kept. N. Y. State Cab. Nat. Hist., pp. 88, 89. 1861. Cryptonetla, Hall. Fourteenth Ann. Kept. N. Y. State Cab. Nat. Hist., p. 102. 1862. CryptanfUa, Hall. Fifteenth Ann. Kept. N. Y. State Cab. Nat. Hist., pi. iii, figs. 6, 7, 8, 9. 1862. Cryptonella, Billings. Canadian Naturalist and Geolo^'ist, vol. vii, p. 392. 1868. Cryptonella {partim). Hall. Sixteenth Ann. Rei>t. N. Y. State Cab. Nat. Hist., p. 42, figs. 8-11; p. 43, figp. 8-11; p. 48. figs. 22, 23 ; p. 49, figs. 24-26. 1863. Vryptonella {partim), Hall. American Jour. Sci., vol. xxxv, p. 39G. 1863. Cryptonella (partim), Billing.s. American Jour. Sci., vol. xxxvi, p. 238. 1863. Cryptonella (partim). Hall. Transactions of the Albany Institute, vol. iv, pp. 132, 148. \^i.(})Centrt»ulla, A. Winchkll. Proc. Acad. Nat. Sci. Philadelphia, vol ix, second ser., p. 123. 1867. Cryptonella, Hall. Twentieth Ann. Kept. N. Y. State Cab. Nat. Hist., p. 164. 1867. Tmbratiila, Cryptonella, Hall. Palseontology of New York, vol. iv, pp. 386-389, 391, 398, pi. Ix, figs. 5-16, 32-44, 49-6.'>, 68-71; pi. hi, figs. 1-41. 1868. Centronella, Habtt. Dawson's Acadian Geology, second ed., p. 300, fig. 99. 1873. Cryptonella, Hall and Whitfield. Twenty-fourth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 199. 1874. WaldAeimia, Dbrby. Bull. Cornell Univ., vol. i, No. 2, p. 3, pi. iii, viii, ix. 1879. Retzia, Barrandb. SystSme Siiurien du Centre de la Boheme, vol. v, pis. xiii, cxii. 1882. Waldlteimia, Davidson. British Devonian Brachiopoda, Suppl., pp. 12, 13, pi. i, figs. 1-4. 1884. Cryptonella, Walcott. Monogr. U. S Geol. Survey, vol. viii, p. 163, pi. iv, fig. 4 ; pi. xv., fig. 2 1888. Cryptonella, Hbbbick. Bull. Denison University, vol. iii, j). 48, pi. v, fig. 10. 1890. Terebraiula, Nbitblboth. Kentucky Fossil Shells, p 155, pi. xvi, figs. 20-22, This name, though introduced in 1861, first acquired a positive value in 1867. In the original description of the genus no type-species was designated though several Devonian shells, Terebratula Lincklani, T. rectiroslra T. lens, T. planirostra, were suggested as differing from Terebratula in some external features, and in the character of the muscular impressions. Subsequently, in 1862, the name was applied to a rare and previously undescribed species from the Lower Helderberg, C. eximia, of which figures were given showing the exte- rior, together with illustrations of the interior in a species not named.* In the following year the interpretation of the name was based largely upon the evi- dence of the internal structure presented by the Centronella Julia, A. Winchell, a shell of similar exterior to those upon which Cryptonella has been founded.f The subject was rediscussed in 1867 (Palaeontology of New York, Volume IV, pp. 392, 393) ; the brachidia of two species originally placed under the genus, T. redirostra and T. planirostra, had been developed, and as this evidence is of * Fifteenth Ann. Kept. N. Y. 8tote Cab. Nat. Hist., pi. iii, tigt<. 6-9. t Sixteenth Ann. Kept. N. Y. State Cab. Nat. Hist., p. 43. BRACHIOPODA. 287 primary importance we must accept this rehabilitation of the genus. Thus constituted Cryptonella includes a group of terebratuloid shells having the following characters : Valves subequally convex ; elongate-oval in outline, broadest in the pallial region. Pedicle- valve with prominent, erect or slightly incurved umbo ; del- tidial plates well developed ; foramen circular, apical, rarely encroaching upon the umbo, or becoming oval as in many species of Dielasma ; the inverted pedicle-sheath or collar is slightly developed within the aperture. The teeth are strong and supported by dental lamellae which divide the umbonal cavity into three chambers ; near the apex they join the somewhat thickened scar of the pedicle-muscle, and extend beyond its anterior margin with a slight con- vergence, resting always on the bottom of the valve. The pedicle-muscle makes the strongest scar of all the muscular bands, the adductors being narrow and central, and the diductors scarcely delimited. In the brachial valve the hinge-plate is large, elongate and concave ; it is divided by two low ridges diverging from the apex, and from these the plate rises toward the sides into decidedly elevated socket-walls ; between the diverg- ing ridges the surface is rather deeply depressed, and, toward the apex, is per- forated by a circular foramen. The crura are slender, very short, curving inward and upward, making two long and narrow crural apophyses. The descending lamellae are carried forward, following the curves of the valves Kio. 20S. Cryptonella planirottra, HaW. The brachidlam; showing the long descending and ascending lamellae. for nearly two-thirds the length of the shell, and abruptly reflected; the ascending lamellae returning to within a short distance of the crural apophyses. 288 PALEONTOLOGY OF NEW YORK. The whole structure is very similar to the brachidium of the adult living Magellania (Waldheimia).* The adductor scars are more or less distinct, the anterior members being the more clearly defined. These scars are usually represented only by three straight lines diverging from the umbonal region. Vascular sinuses originate about the muscular areas of both valves and are directed forward with frequent rami- fications. The shell-structure is highly punctate. It thus appears that the Devonian shells which can be referred to Crypto- nella do not materially differ in the structure of the brachidium from the living Magellania. There are several species in the American faunas, currently referred to this genus, whose brachidia have not yet been developed, e. g., C. eximia, Hall, of the Lower Helderberg, C. Iphis, Hall, of the Upper Helder- berg, and C. Eudora, Hall, of the Chemung, but in all these the probability of their being congeneric with C. rectirostra, is enhanced by the demonstration of the absence of the transverse dorsal band on the brachidium of the latter. From Davidson's determinations we know that the same type of brachidium existed in the Devonian faunas of Great Britain, Waldheimia juvenis, Sowerby (sp.), and W. Whidbornii, Davidson,! both shells with smooth exterior, the latter with biconvex valves, the former with a plano-convex or centronellid contour. From certain preparations made by Dr. Carl Rominger, in 1863,J it was deter- mined that the Terebratula or Retzia melonica, Barrande, from the Bohemian Etage Fj (Konieprusian), possesses a brachidium of the same type. This is a large biconvex shell quite different in expression from the diminutive navicu- * In the description and illlustratioDS of 18ti7 the brachidium was represented as possessing a trans- verae band on the dorsal side, uniting the descending branches at points just below, and slightly back of the position of the crural apophyses. Such a transvei-se band does not exist. In making preparations of these internal parts slight ineptitude will divide the long concave hinge-plate in such a manner that ite anterior edge remains attached to the crura. Repeated attempts with the knife have almost invariably given this result, but certain specimens in which the entire brachidium has been changed to pyrites have determined the inaccuracy of such preparations and the absence of this abnormal structure. t Devonian Supplement, 1882, pp. 13, 13, pi. i, figs. 1-4. I Sixteenth Report on New York State Cabinet of Natural History, p. 49, figs. 24-26. See also Bar- KAXOK, Systime Silurien, vol. v, pi. cxli. 1879. BRACHIOPODA. 289 loid shell from the upper Wenlock shales which Davidson has described* as Waldhdtnia Mawi ; a species which strikingly resembles Cyclospira bisulcata, both in form and size. This shell has a low median septum in the brachial valve, and its brachidium is longer and much broader than in those of the Devonian. In all of Davidson's representations of the interior of these species, the hinge- plate, which we may assume to be somewhat constructive, is given with a distinct cardinal process in the Devonian species, like that of the living Magellania, though in W. Mawi there appears to be a trace of a perforation in the plate. These structures, however, are not fully described. The actual difference in the composition of this plate in the recent Magellanias and the Devonian Cryptonellas, as above described, may be regarded as a highly impor- tant basis of distinction between these forms. Were it necessary, however, to rely upon this difference alone, we should fall far short of separating their remote predecessors of the palaeozoic era as widely from Magellania as the evidence seems to require. The form of the long, recurved adult loop in such living genera as Magella- nia, Macandbewia and Terebratella, has been shown by various investigators to be but the terminal condition of a series of metamorphoses. Evidence con- cerning the immature condition of the loop in any of the fossil terebratuloids is extremely difficult to obtain. In the very early growth-stages of Cryptonella planirostra, where the shell has a length of not more than 4 or 6 mm., the bra- chidium is simply a miniature of its adult condition. However, from what we now know of the changes in living and extinct Brachiopoda of similar char- acter, it seems a natural and necessary inference that the brachidia of all such terebratuloids have undergone modifications or metamorphoses which, though slight in comparison with similar changes in the living species, yet do involve a progressive change from the simple loop of Renssel^eria and Centronella to the resultant acquired in Magellania and Terebratella of modern seas. It should not be overlooked, however, that in the recent genera of terebratu- loids these modifications of the loop are complicated by the presence of a median septum, which is an integral part of the brachidium, and the absence of such a ♦ Silurian Supplement, 1882, pp. 76, 77, pi. iv, figs. 1-3. 290 PALAEONTOLOGY OF NEW YORK. septum in these Devonian and Carboniferous terebratuloids gives a greater sim- plicity to the variations of the loop in different st+Vi gate, sessile hinge-plato with its muscular scars, and the the brachial valve, the scars Ol both fo^m^nd mode of attachment of the Uiachidium. anterior and posterior adductors being (davidsost.) frequently clearly defined upon its surface. Upon comparison of this structure with that of Cryptonella the homologies are at once apparent, but there is a 296 PALEONTOLOGY OF NEW YORK. total difference in the expression of the two. The lateral divisions of the plate in Cryptonella have become merged with the valve and lost in Dielasma. The median division, which is also to a certain extent myiferous in Crypto- nella, is carried to an extreme of development in Dielasma, where it forms a distinct platform. In Dielasma the crura are greatly abbreviated. The descending lamellae of the brachidium are attached to, and are continuous with the crural plates, as far as the latter extend. The crural apophyses on the upper margins of these lamellsB are developed behind the points where the lower margins of the lamellae are free from the crural plates. The lateral parts of the brachidium are more or less divergent, the recurvature of the ascending lamellae rather short and the entire structure does not extend beyond the mid- dle of the shell. The ascending lamellae are very fragile and usually destroyed in fossilization. It is thus evident that the differentials of Dielasma are highly developed and these having become fixed at the opening of the Carboniferous period, species of the genus abounded until the close of the Permian. In American faunas the specific values of these forms have not been thor- oughly determined, but we may quote as characteristic examples of Dielasma, the following: Terebratula formosa and T. turgida, Hall, of the Warsaw lime- stone, T. Rowleyi, Worthen, and T. Burlingtonensis, White, of the Burlington limestone, and T. bovidens, Morton, of the Coal Measures. The type of structure was, however, well defined in the Devonian, and the Cryptonella Calvini, Hall and Whitfield, of the middle Devonian of Iowa, is an excellent representative of the earliest forms of the genus. The great specific representation of the genus in the later Carboniferous faunas has been demonstrated by the labors of De Koninck* and WAAGEN.f It has been suggested by WaaqenJ that the Terebratula Lincklani, Hall, of the Hamilton fauna of New York, might prove to be an early representative of D1ELA8MA. Reasons have already been advanced to show that this species, with * Paune du Calcaire Carboniftre de la Belgique ; Ann. du Mus N. T. d'Hist. Nat. de Belg., voL xiv, pt. vi, pp. 5-31, pis. i-viii. 1887. t Palaontologia Indica ; Productus-Iimestone Fossils, pp. 336-359, pis. xxv-xxvii. 1882. r Xpp. cU., p. 337. BRACHIOPODA. 297 T. simulator. Hall, and some others, possessing a narrow and slightly recurved but decidedly elongate brachidium, conveniently constitute a subdivision of Crtptonella. But there are other Devonian species in which the loop is far more like that of Dielasma, as for example the Terebratula Romingert, Hall, a form widely distributed in the Hamilton fauna of North America ; and the T. {Cryptonella) lowensis, Calvin, a large, biconvex, and often beautifully pre- served shell, from the middle Devonian of Fayette and elsewhere in Iowa* In this shell the hinge-plate is constructed as in Cryptonella and is not adherent to the bottom of the valve as in Dielasma, though it may be close to it ; the crura also arise normally from the lateral divisions of this plate. With these distinctive differences from Dielasma, the resemblance to the latter genus in the form of the brachidium is striking, its descending branches being highly fig. 215. Ta-ebratulaiCranana) Komingeri, H&U. ,. ■ .1 T 1 I 1 An oatline showing the Dielasma form of the brachidium divergent, the ascendmg branches ab- and the divide.i hinge-piate. ruptly recurved, making a broad, gentle curvature above ; at the same time this recurved band is so very fragile as to be almost invariably destroyed. The entire length of the loop, as in Dielasma, and in contradistinction to Cryptonella and EuNELLA, is aVjout one-third that of the brachial valve. This peculiar structural variation may be designated by the term Cran^na.! Probably other American Devonian species, besides the two mentioned, will be found to belong to this group when satisfactory evidence of their internal structure has been obtained. Recent observations by Beecher and SchuchertJ upon the development of the brachidium in Dielasma turgida, Hall, of the St. Louis limestone, show that in its earliest observed condition, in a shell about 4 mm. in length, it is altogether like that of primitive forms of RENSSELiERiA {R. mutabilis) ; the lateral branches uniting by simple coalescence to form a triangular median plate, which is not thickened along the line of suture, either below, as in R. mutabilis, or above, as * Caltuc, Bull. Lab. State Univereity of Iowa, p. 174, pi. iii, fig. 4. t To Miss AoirBS Cbaitb, of Brighton, England, an associate in the later laboi's. of Dr. Thomas David- sou, and an astute student of the Brachiopoda. X Development of the Brachial Supports in Dielasma and Zygospira, op. cit. 1893. 298 PALEONTOLOGY OF NEW YORK. in Centronella. The adult condition of the loop is derived from this primitive condition by progressive resorption of the pointed anterior portion of the plate, and the complete obscuration of the median suture by anchylosis is not effected no. 216. FlO. 217. Flu. 218. DieUuma turgida. Ball. Fig. 216. The oenlroneUU'omi stage of tbo loop, x u. Fig. 217. A later stage; showing the resorption of the anterior portion of the loop. X 6. Fig. 218. Early DiELASMA stage, produced by further resorption. X 6. Fig. 219. Loop and hinge-plate of a mature specimen. X 6. Fio. 219. till near maturity. It is thus clearly demonstrated that the brachidium of DiELASMA and, inferentially, all similarly recurved loops are secondary modifica- tions of the primitive structure finding its mature expression in Renssel^eria and Centronella. DIELASMINA, Waagen. 1882. 188'2. Dielastnina, Waauiui. Pi-oduutus-limestone Fossils ; Brachiopoda, p. 3ti9, pi. xxvii, tig. 10. This name has been applied to certain plicated species in the Productus- limestone of India, which possess more or less of the characters of Dielasma. no. MO. Fio 221. SUlatmina pUctita, Waagen. Dorsal and frontal views. (Waagen.) They have the dental plates of the pedicle-valve and the general form of the brachidium in that genus, as far as the interior is now known, but for the BRACHIOPODA. 299 present the distinctive difference lies in the nature of the exterior. This dis- tinction is certainly a convenient one, but the type of structure, so far as our knowledge extends, is unknown in American faunas. The type-species of this genus is D. plicata, Waagen, and this is said to be its only repre- sentative. HEMIPTYCHINA, Waagen. 1882. 1862. Terebratvla, Davidsoit. Quart. Journ. Geol. Soc. London, vol. xviii, p. 27, pi. ii, tig. 1. 1863. Terebratula, db Koninck. Fobs. Pal6oz. de I'lnde, p. 32, pi. ix, fig. 1. 1878. Terebratula, Waagbn. Records Geol. Surv. India, vol. ix, p. 186. 1882. Hemiptychina, Waaokn. Productus-limestone Fossils ; Brachiopoda, pp. 361-376, pi. xxvi, figs. 6-10; pi. xxvii, tigs. 1-9, 11. Dr. Waagen has found that certain plicated terebratuloids of Permo-Carbon- iferous faunas do not possess dental plates. The significance of the generic name above used and the nature of the author's argument, both indicate that the conception of the proposed genus was based upon such plicated shells. The author, however, adds that the plica- tion of the exterior "is not absolutely indispensable for the shells belonging to the genus" {op. cit, p. 361) and, un- fortunately, without citing any species as typical, gives, first in his list of descriptions a smooth shell, H. SUbl2. HemtptycMna mmalayenau, Davidson. WflAO-pn Thp nrnnrietv of inoludinff a portion of the interior; sliowiug Uie absence of dental W aagen. l ne propriety OI ini^lUUlUg p,^^^ .^ ^^^ peUicIe-valve, and the DiKtASMA-Uke these plicated and smooth shells in the brachidiun.. (waaoek.) same genus appears, on certain grounds, open to objection ; and the author's intention will undoubtedly be better interpreted by regarding the plicated shell, Terebratula Himalayensis, Davidson, as typical of the Hemiptychina; a shell of whose interior something is known and from which it is clearly evident that the author's diagnosis was largely drawn. These plicated terebratuloids without dental plates are unknown in American faunas ; but we do find a very limited representation (as yet restricted to a 300 PALEONTOLOGY OF NEW YORK. Fio. 2S3. Btechtria [Btmiptycliina) tublatU, Waagen. Dorsal view; 8howinK the smooth exterior. (Waagrk.) single form) of smooth species without dental plates. It is here proposed to separate these shells from Hemiptt- CHiNA and to distinguish them by the term Beecheria,* giving a brief account of the interior structure as exemplified in B. Davidsmi, sp. nov.,f of the Carboniferous limestone of Windsor, Nova Scotia. The general character of the interior is that of Dielasma, except that the dental plates are wholly absent or represented only by faint ridges which never reach the bottom of the pedicle- valve. The peculiar myiferous hinge- plate of Dielasma is wholly merged with the valve, but the crural ridges are still retained and the descending lamellaB originate from them at the bottom of the valve in very much the same way as in Dielasma. The crural apophyses are broad and erect, there being no part of the descending branches behind them. Sometimes the brachial valve retains a low muscular impression which has the form of the platform of Dielasma. This species and Beecheria {Hemiptychina) sublavis, Waagen, constitute the known representatives of this type of structural variation. no. 2-24. Beecheria DatidtoiU, sp. nov. An enlarxc'l proOle ol' the brachidium; showing the man- ner in which lamellae arise [rota the bottom of the raire, the broad posterior JURal processes and the much nar- rower descending lamcllie. The anterior transverse or reflected band is not fully retained. (c ) Gencs CRYPTACANTHIA, White and St. John. 1867. 1867. Waldheitniaf (Cryptacanthia), White and St. John. Trans. Chicago Academy of Sciences, vol. i, pt. i, p. 119, fig. 3. Our knowledge of this genus is still very imperfect. The authors described as Waldhdntia? compada, a rather small, plano-convex or naviculoid shell from * In recognition of his important contributions to our knowledge of the Brachiopoda. t This is the shell identified by Davidson as Terebratulu sacctdus, Martin. (On the Lower Carboniferous Brachiopoda of Nova Scotia; Quart. Journ. Geol. Soc., vol. xix, p. 169, pi. ix, figs. 1-3, 1863.) BRACHIOPODA. 301 FlO. 228. Watdheimial {Cryptacanthia) compacta, White and St. John. A copy of the original flgaro. . (White and St. John.) the Upper Coal Measures of Madison county, Iowa, where it is said to be associated with the Terebratula millipundata, Hall {=Dielasma bovidens, Martin). The original figures showing the outline of the exterior are here reproduced. Of the internal structure the authors say that " the loop seems to be essen- tially like that of Waldheimia in form, but the crura of the loop ap- pear to be joined, forming with the hinge-plate a foramen of moderate size ; and the loop-band is armed with numerous spines which point outward towards the shell in all di- rections." This shell appears to be very rare, and we have had no opportunity of examining specimens. Attention, however, may be directed to a somewhat similar form of brachidium from the chert beds of the Burlington lime- stone, at Burlington, Iowa, belonging to a species whose identity is not fully established. This structure is represented in the accompanying figure. From a well-developed, elevated and tripar- tite hinge-plate, bearing a slight bi- lobed cardinal process at its apex, arises a very short brachidium of the type of DiKLASMA or Cban.«;na. The outer margins of both descending la- mellae and the short ascending lamellae are bordered with numerous short spin- ules. Furthermore, there appears to be a solid longitudinal band passing from the hinge-plate to the posterior curve of the ascending lamellae. This curious character is not a septum, as the entire apparatus is elevated from the bottom of the valve ; but it may prove to be wholly casual, and a result of an interlocking of the minute quartz crystals with which the brachidium is Fio. 226. A fimbriated DIELASHA-Iike brachidium from the chert of the Burlington limestone. The median dotted lines indicate'the position of the longi- tudinal band described as probably casnal in origin. The oatline of the valve is wholly constructive. 302 PALEONTOLOGY OF NEW YORK. encrusted. Possibly a similar occurrence explains the apparent union of the crural apophyses described by White and St. John as occuring in Cryptacan- THiA. The external form of the Burlington limestone species is apparently more biconvex than in Cryptacanthia compada, and the generic characters of both are extremely uncertain. Genus T ROP IDOL E PTU S, Hall. 1857. PLATE LXXXn. 1889. StTophmnena, Cohrad. Ann. RepU Oeolog. Dept. N. Y., p. 64. 1847. Leptana, dk Vrenbdil. BuU. 8oc. G£oL de Prance, second ser., voL iv, p. 706, pi. iii, figs. 7, 7o. 1853. Leptana, Schndr. Palteontographica, vol. iii, p. 220, pi. xl, fig. 2. 1856. Strophomena, Thb SANDBERaERS. Verstein. der rhein. Schichten-systems, p. 66, pi. xxxiv, fig. 8. 1867. Tropidoleptut, Hall. Tenth Ann. Kept. N. Y. State Cab. Nat. Hist., p. 151, figs. 1, 2. 1859. Tropidoleptiis, Hall. Twelfth Ann. Kept. N. Y. State Cal.. Nat. Hist., p. 31. 1866. Leptaena f Uavidsok. British Devonian Brachiopoda, p. 87, pi. xvii, figs. 1-3. 1867. lyopidoleptus, Hall. Palteontology of New Yoi-k, vol. iv, p. 404, pi. ixi a, figs. 60-62 ; pi. Ixii, figs. 2o-c, 3a-y. 1868. Tropidoleptux, Meek and Worthem. Geology of Illinois, vol. iii, p. 427, pi. xiii, fig. 2. 1874. Tropidoleptus, Rathbdk. Bull. Buffalo Soc. Nat. Sci., vol. i, p. 254, pi. ix, fig. 10. 1876. Tropidoleptus, Derby. Bull. Mus. Harvard Coll., vol. iii. No. 12, p. 282. 1881. TVopidoleptus, Rathbck. Proc. Boston Soc. Nat. Hist., vol. xx, p. 35. 1889. TwpidoUptus, Nbttelhoth. Kentucky Fossil Shells, p. 46, pi. xvii, figs. 14, 15. 1890. DropidolepUis, Derby. Arch. Mus. Nac. de Rio de Janeii'o, vol. ix, p. 76. 1892. Tropidoleptus, Ulrich. Paleoz. Verstein. aus Bolivien ; Neues Jahrb. ftlr Minei-al., etc., Bei- lagebnd. viii, p. 73, pi. iv, figs. 32-34. Diagnosis. Shells with the general external aspect of Rafinesquina ; concavo-, or plano-convex. Hinge-line straight; in young shells form- ing the greatest transverse diameter and frequently extended at the cardinal extremities, but in mature and old shells shorter than the trans- verse diameter in the pallial region. Marginal outline varying from longitudinally semi-elliptical in youth, to transversely subelliptical at ma- turity. Surface covered with simple, low plications, all extending from beak to margins. The median plication on the pedicle-valve and the corresponding sinus on the brachial valve are broader and more conspicuous than the others. BRACHIOPODA. 303 The pedicle-valve is regularly convex, becoming slightly concave on the cardinal slopes. It bears a moderately broad cardinal area, coextensive with the hinge-line, which is divided by a broad, open delthyrium, which, in no observed condition of growth, bears a covering of any sort, but is filled by the cardinal process of the other valve. The base of the delthyrial cavity is thickened and transversely striated, probably by the attachment of the pedicle-muscle. The teeth are not situated at the extremities of the delthyrial margins, but lie within and in front of them, arise from the bottom of the valve as two erect, divergent subquadrate crests, rest- ing upon low ridges which bound the muscular area. These peculiar teeth are smooth and abrupt on their inner faces, while their outer faces are deeply crenulated. A low groove separates each from the cardinal area. The muscular area is broadly flabellate, extending more than half-way across the valve, and consists of two large diductor scars enclosing a narrow median pair of adductors. The brachial valve is slightly concave, often nearly flat. Cardinal area nar- row, but clearly developed; chilidium prominent. Cardinal process large, erect, smooth on its posterior surface, and bilobed at its summit. Each of these lobes is excavated above, so that the upper portion of the posterior wall is free from the rest of the process. In front of this is a broad, smooth floor, sloping toward the bottom of the valve. The margins of this area form the elevated socket-walls, and their anterior extremities are the bases of the crura. The dental sockets are deep and their outer walls corrugated for the reception of the teeth. The posterior portion of the sockets and the lower part of the cardinal process are covered by the erect, convex chilidium. At the anterior edge of the cardinal process lies a broad, thick, not elevated median ridge, which gradually narrows and becomes developed into a sharp, thin septum, attaining its highest point at about the center of the valve, whence it slopes rather more abruptly downward, terminating at the anterior third of the valve. From the crural bases extends a pair of long, slender lamellar processes, which curve outward, are directed upward, again converge and unite with the median septum on its lateral faces and just in front of its highest point. Slightly con- 304 PALJEONTOLOGY OF NEW YORK. vergent, slender jugal processes are given oflf not far from the origin of the lateral lamellae. The scars of the adductor muscles are situated just in front of the cardinal process on either side of the septum, and are not clearly delimited. Shell-substance highly punctated in all its part*. Type, Strophomena carinata, Conrad. Lower and middle Devonian. Obseevations. The original determination of the characters of Tropidoleptus led to its assignment with the terebratuloids. Presumably on account of its external expression, systematists and other students have generally been un- willing to admit this determination, placing the genus preferably among the strophomenoid and leptaenoid genera. After the examination of a large amount FIO. S27. FlO. 228. TVopUloUptut carinatut, Conrad. ng. 227. The Interior of the brachial valve; showing ihe^urilinal process, creuulated dental sockcla, loop and median septnm. Fi|r. 228. The same In profile; showing the height of the median septum and the mode of attachment of the lamellffi of the loop. of material, representing the various growth-stages of the shell from a size less than 2 mm. in diameter to maturity, and having reviewed all the points involved in the original account of the brachidium, these have been found to be correct in every particular. In no observed condition of growth does there exist a deltidium on the pedicle-valve, and hence it becomes necessary to recognize Tropidoleptus as a terebratuloid genus, unique among the palaeozoic brachiopoda. BRACHIOPODA. 305 The actual union of the lateral lamellas of the brachidium with the median septum in this shell is the earliest evidence and only known instance in palaeozoic faunas of a condition which is prevalent among the terebratuloids of existing seas. The investigations of Davidson, Dall, Friele, CEhlert and Beecher have shown that in Terebratella, Magasella, Kraussina, Platidia, BoucHARuiA, and, indeed, all genera where the median septum is highly devel- oped, the calcification of the lamellae of the brachidium begins quite as soon from the lateral walls of the septum as from the crural bases on the hinge-plate. Calcification thus proceeds both posteriorly and anteriorly. In all modifica- tions of the brachidium attendant upon the resorption of later growth, the median septum is most intimately concerned, and in the terminal stage of such modifications every trace of this septum may have been removed (compare Magellania venosa, Macandrevia cranium). The mature condition of Tropidoleptus, when compared with the variations from resorption, through which the loop of the Terebratellid^ has passed, is found to be very simple, showing only the primary completed calcification of the lateral branches or descending lamellae, and affording no evidence whatever of any modification resulting from resorption of the calcified tissues. Its con- dition is directly comparable to the mature form of the loop in Platidia, and to what is termed by Beecher the platidiform stage in Mchlfeldtia and Macandre- via.* The transverse and strongly plicated valves with well developed cardinal areas, are features in harmony with the condition of the brachidium, as similar characters are borne in the primitive conditions expressed by the mature Kraus- sina, CiSTELLA, Megathyris, ctc. Immature specimens of Tropidoleptus fre- quently show an uncompleted condition of the calcification of the brachidium. All the evidence thus points to the conclusion that this interesting genus is an early representative of the family Teuebratbllid^. The wide distribution of T. carinatus through the Devonian of North and South America has already been referred to in the discussion of the genus Vitu- LiNA. In the argillaceous shales of the Hamilton group in western New York * See Revisiiin of the Families of the Looi)-bearing Brachiopoda, by Cuablbs E. Ukbchbk; Transac- tions of the Connecticut Academy, vol. ix, p. 376, pi. i. 1893. 306 PALEONTOLOGY OF NEW YORK. the species is exceedingly abundant and very generally distributed, but it is rarer toward the east where deposits become more arenaceous. Yet wherever the Devonian sandstones are known in Brazil and Bolivia the species abounds. A similar form passing current under the name Strophomena or Leptana laticosta, Conrad, also occurs in the lower Devonian sandstones (Coblentzian) of Germany. An additional species, T. occidens, Hall, has been described from the limestones of Hamilton age at Iowa City, Iowa, but its internal characters are not known. BRACHIOPODA. 307 OEN BRA WHOSE SYSTEMATIC POSITION IS UNDETERMINED. Genus EICHWALDIA, Billings. 1858. PLATE T.YYTTTT 1848. Terebratula, Davidsom. Bull. Soc. Geol. de France, second ser., vol. v, pi. iii, fig-. 34. 1849. Atrypa, d'Orbigny. Prodrome de Pal^onlologie, vol. i, p. 40. 1852. Atrypa, Hall. Paleontology of New York, vol. ii, p. 281, pi. ivii, tigs. 5 a-t. 1858. Eichxoaldia, Billinqs. Re|>t. Geol. Survey Canada for 1857, p. 190, figs. 24a-e. 1859. Hhynchonella, PoramlKmites, Salter. Murchison's Siluria, second ed., pp. 250, 544. 1860. Porambonites, Lindstrom. Gotland's Brachiopoden, p. 364. 1863. Khynchonellaf Hall. Transactions of the Albany Institute, vol. iv, p. 217. J866. EichvxUdia, Billino.s. Catalogue Silurian Foss. Anticosti, p. 10. 1867. EichvxUdia, Dictyonella, Hall. Twentieth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 274-278, figs. 1-7. 1869. Eichwaldiaf Davidson. British Silurian Brachiopoda, p. 193, pi. xxv, figs. 12-15. 1875. Eichvxildia, Hall. Twenty-eighth Ann. Rept. N. Y. State Mus. Nat. Hist., p. 159, pi. xxvi, figs. 50-54. 1879. EichvxUdia, Bakhandb. SystSme Silurien du Centi-e de la Boheme, vol. v, pi. Ixxxi. figs. I-III. 1880. Eichwaldia, Lindstrom. Angelin's Fragmenta Silurica, p. 25, pi. ii, figs. 16-20. 1883. Eichwaldia, Datidsos. British Silurian Brachiopoda, Suppl., p. 140, pi. viii, figs. 15, 16. 1884. EichvxUdia^ DAViDfcON. British Fossil Brachiopoda, General Summary, p. 355. 1884. EichvxUdia, Yonsa. Geological Magazine, vol. i, No. 5, p. 214. 1889. Eichvxildia, Bkbchkk and Clabkb. Mem. N. Y. State Mu't., vol. i, No. 1, p. 31, pi. iii, tigs. 11-13. These curious shells have been carefully studied by Billings, Hall, Davidson, Lindstrom and Young, and though we have a pretty complete understanding of their structure, their affinities and phylogeny are still obscure. Their charac- ters are as follows : Shells subtriangular in outline, with biconvex valves, the pedicle-valve hav- ing a broad median sinus, and the brachial valve a corresponding median fold. The umbo of the pedicle-valve is acute and arched over the opposite valve, though not closely appressed against it. As far as has been ascertained, the umbonal space between the two valves is open, that is, there is no normal delti- dium or pair of deltidial plates extending from the apex downward ; but there is a 308 PALEONTOLOGY OF NEW YORK.\ short, triangular plate or diaphragm which begins at the apex of this valve, and extends forward beyond the posterior edge of the brachial valve, and thus serves the purpose of the deltidium, though deeply depressed within the cavity of the pedicle-valve. This diaphragm is usually quite short and confined to the apical region, but it may extend for fully one-fifth the length of the valve, its anterior margin being free and its lateral margins adherent to the inner cardinal slopes. The cardinal line may be regarded as extending nearly to the lateral ex- tremities of the valves ; the articulating apparatus consists of a pair of long marginal ridge-like teeth on the divergent cardinal slopes, fitting into narrow marginal grooves on the brachial valve. There is sometimes a trace of a median septum over the pallial region. In the brachial valve is a small callus, boss or cardinal process lying directly beneath the apex. Below this is a strong Fio. 229. Fig. 231. Fio. 232. Fio. 233. Eichwaldia reticulata,' Hall. Fio. 280. wrrrrnrrri {/m^^y FIO. 2.15. Fig. 233. Interior of brachial valve. Fig. t34. Vertical section of shell. Fig. 285. Enlargement of tlic surface. Fig. 229. Doraal view. Fig. 230. Cardinal view. Fig. 231. Longitudinal section of the two valves. Fig. 232. Interior of pedicle-valve. Notaiion i t, " bare spot," foramen ? ; p(o), deltidlain or internal plate; c', umbonal surface of pedioie-valve; T, teeth; B, dental sockets; j, cardinal process; 8, median septum of brachial valve. median septum, which increases in height anteriorly and rises to an acute, an- teriorly directed apex at about two-thirds the length of the shell. In front of BRACHIOPODA. 309 this point its anterior edge is concave, the septum disappearing not far within the margin of the valve. No traces of muscular scars have been observed on either valve. The external surface of the valves is covered by a coarse network of super- ficial cells, usually hexagonal, sometimes circular in outline. In all species and in early growth-stages there is a bare, smooth, triangular area at the beak of the pedicle-valve, where this superficial ornament does not extend. It has been shown by Young that the shell of Eichwaldia CapewelH is composed of three layers ; first, the outer, coarsely meshed and wholly superficial layer ; below this, a more compact layer perforated by numerous small polygonal cells. FIO. 236. ri(J.237. Fig! 538. Fio. 239. FiG. 240. EiehuxUdia CapeweM, Davidson. Fig. 236. Hexagonal cells of the outer surface of tlie sltell in unworn specimens. Fig. 2S7. Small polygonal cells in walls of hexagonal cells. Jig. 238. Polygonal cell layer between outer hexagonal cells and inner dense layer. Fig. 238. Perforated inner dense layer. Fig. 240. Vertical section of the shell; a, outer hexagonal cell-walls; b, polygonal cell layer; c, inner dense layer with minute perforations. (Youno ) the apertures of which are exposed in the greater cells of the outer layer; and, on the inner surface, a dense lamina with minute perforations. The peculiar bare spot on the umbo of the pedicle-valve, from which the external shell-layers are absent, requires a brief notice. This area is the open- ing of an aperture entering the valve between the outer shell and the internal umbonal diaphragm. The smooth surface of the area is the inner surface of this diaphragm, which is considerably thickened about its apex. Young has called attention to the fact that along the margins of this bare spot the superficial laminae are unfinished and the edges of this outer layer rough and ragged. This is especially true of the anterior edge, while the lateral edges appear to be invariably straight and to diverge at a constant angle.* The lat- ter evidently represent the lines of attachment of the internal diaphragm to the lateral walls of the valve. In the youngest shells that have been observedf *8ee Bkhohbr and Clabkb, Memoirs N. Y. State Museum, vol. i, No. 1, p. 32. t Babrahdb, SystJme Silurian, vol. v, pi. Ixxxi, tigs. 1, 2j Beecubs and Clabke, op. cit, pi. iii, fig. 11. 810 PALEONTOLOGY OF NEW YORK. this smooth spot is present and it is always accompanied by a decided incurva- ture of the apex of the valve. The condition of the edges of this aperture has convinced some observers of the probable atrophy of the pedicle, and the fixation of the shell by solid cementation at this point. It must, however, be borne in mind that among the □ FIO. 2')1. fio. Hi. Eichwaldia tubtrigonalit, liillings. Doraal and ventral views ofa silicifleil young shell retaining the pedicle; showing its protrusion from the umbona aperture. From photographs of the original specimen described l>y Rillinos. original illustrations of the type-species, E. subtrigonalis, Mr. Billings represented a young shell in a silicified condition, with an extended pedicle protruding from, or at least covering the aperture represented by the bare spot. Through favor of Mr. J. F. Whiteaves, of the Geological Survey of Canada, we have been furnished with photographs and drawings of this specimen, and notwith- standing this remarkable instance of the replacement of a soft organ by silica, there seems, from this evidence, to be no reason to doubt that the umbonal aperture was solely for the passage of the pedicle. Such being the case, it will naturally follow that the internal plate or umbonal diaphragm is a modified condition of the deltidium or of the deltidial plates, probably the former. The earliest species of this genus, of which we have information, is the type- form, E. subtrigonalis, Billings, which was described from the Black River lime- stone at Paquette's Rapids, on the Ottawa River. The other American species are all from the Niagara faunas, E. coralifera, Hall, occurring in the New York shales, E. reticulata. Hall, in the calcareous shales at Waldron, Indiana, E. gib- bosa and E. concinna, Hall, in the limestones of western Tennessee, and E. Anticostiensis, Billings, from Anticosti. Eichwaldia Capewelli, Davidson, appears to be not uncommon in the Wenlock shales of England, and has been identified by Lindstrcim, in the Island of Gotland. Barrande has illustrated three species from the (''tages E and G, namely, E. Dormitzeri, E. Branikensis, E. Bohemica, Barrande. BRACHIOPODA. 311 It may be well to observe that as the species E. subtrigonalis, upon which the genus was established, has a surface quite devoid of the cellular epithelial lamina which is so characteristic of all the other known species, the term DiCTYONELLA, Hall (1867),* may be found of use in distinguishing the latter group of shells. Genus AULACORHYNCHUS, Dittmar. 1871. PLATE LXXXIII. 1854. Chonetesf Sbmbkow. Zeitschr. der deutsch. geolog. Gesellschaft, vol. vi, p. 34.'), pi. v, figs. la-d. 1862. Chonetes, Davidsox. British Carboniferous Brachiopoda, p. 278, pi. Iv, fig. 13. 1871. Aviamrhynehus, DwTKKVi. Ueber ein neues Brachiopoden-Geschlecht aiis dem Bergkalk ; Verb. d. k. Akad. d. Wissensch. St. Petersburg, second ser., vol. vii, p. 1, pi. i. 1870. Chonetes f1 Meek and Wobthen. Proc. Acad. Nat. Sci. Philadelphia, p. 35. 1873. Isogramma, Mbek and Wobthek. Geological Survey of Illinois, vol. v, p. 568, pi. xxv, figs. Za-d. 1882. Aulacorhynchics, Barrois. Recherches sur les Terrains anciens des Asturies et de la Gallice, p. 326, pi. xvi, figs. 6a-d. 1884. Avlacorhynchrts, Davidson. British Fossil Brachiopoda; Appendix to Supplements, p. 283, pi. XX, fig. 22. Shells short, transversely elongate or alate; extremities often rounded; hinge-line straight, usually making the greatest width of the shell. Valves very thin and fragile. Pedicle-valve slightly convex, with traces of a broad, obscure lujdian sinus; brachial valve flat. Surface covered with numerous regular and continuous, concentric rounded folds or ridges which are separated by fur- rows of equal width. In the pedicle-valve the character of the articulating processes has not been fully ascertained. There appears, however, to have been no cardinal area, and but exceedingly small teeth, judging from the analogy of the brachial valve. Just within the apex of the valve, which is closely appressed against the oppo- site one, begins a pair of divergent, elevated ridges, which extend for one-third, or even one-half the length of the shell, and enclose a thickened area or plat- form, which terminates abruptly in a transverse anterior margin. This platform is the seat of the adductor and divaricator muscles, and probably rests upon the bottom of the valve and is not vaulted. In the brachial valve there is a prominent cardinal process from the base of which diverge two lateral ridges or socket- walls, lying just within the hinge-line; •Twentieth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 274. 312 PALJEONTOLOGY OF NEW YORK. behind them are linear depressions or dental sockets. There is also a low median ridge extending from the base of the cardinal process into the pallial region. The substance of the shell shows a coarsely prismatic cellular structure, as in PoRAMBONiTES and EiCHWALDtA. According to Barrois, this cellular lamina is not superficial but is covered by a thin epidermal layer. Type, Aulacorhynchus Par.hii, Dittmar. Carboniferous limestone. Observations. There is still much to be learned of the structure of these curious shells. Their similarity in external aspect to De Koninck's Chonetes concerUrica, led some of the early writers to refer them to that genus and species, but Semenow, the first author to notice these fossils, observed their differ- ences from Chonetes, in the absence of cardinal spines and the existence of a thickened triangular plate in the pedicle-valve, and suggested that they were to be regarded as typical of a new brachiopod genus. Meek and Worthen are the only authors who have described the brachial valve, and upon it was based the conception of their genus Isogramma, which must yield to Dittmar's term introduced two years earlier. More recently Barrois has added some important observations upon the structure of the genus. Species of this genus are not common, but appear to be widely distributed in Carboniferous countries, Russia, Silesia, Scotland, and the Asturias. In North America the only species known is the Isogramma millepundata, Meek and Worthen, from the upper Coal Measures of Marion county, Illinois. The origin and affiliations of Aulacorhynchus are involved in great uncer- tainty. The resemblance to Chonetes is fortified by the existence of a stout cardinal process, while the triangular muscular plate, the close incurvature of the beak and obscuration or obliteration of the pedicle-passage and deltidium, are features similar to those existing in Eichwaldia. It may be suggested that the pedicle in Aulacorhvnchus was extruded in a manner similar to that in Eichwaldia, and that, hence, the platform may have been vaulted and slightly raised above the bottom of the valve, though this is not evident from the usual preservation of the fragile shells, where compression has closed any such cavity. These similarities to Eichwaldia are still further seen in the coarse cellular structure of the shell. BRACHIOPODA. 313 Genus LYTTONIA, Waagen. 1883. 1878. Bactrytiium, Waaqbn. Re(;or(]s Geol. Surv. India, vol. xi, pp. 186, 187. 1880. Thecldea, Zdgmatbr. Untei-s. ilber rhat. Brachiopoden ; Beitr. zur Palaon. von Oesterreich- Ungarn, I, p. 22. 1882. Leptodiui, Katsbh. Richthofen's China, vol. iv, p. 161. 1883. Lyttonia, Waagbn. Productus-limestone Fossils ; Biachiopoda, pp. 396-403, pi. ixix, figs. 1-3 ; pi. XXX, fig.0. 1-11. Shells of great size, highly inequivalve and very irregular ; frequently with broad lateral expansions. Pedicle- valve convex, thick ; apex not distinct; hinge-line short and straight ; teeth faintly developed. On the interior are numerous ridges extending in slight curves toward the lateral margins; in the median line is a smooth space bearing a central vertical ridge. Fio. 243. Fig. 2«. Lyttonia nobilit, Waagen. Fig. 243. Cardinal part of a pedicle-valve; etiowing tlie liinge-Iine, median and lateral septa. Fig. 244. A. portion of the interior of a brachial valve. (Waagen. I Brachial valve operculiform, not extending to the margins of the opposite valve. Cardinal process small and bilobed ; median surface of the interior with divergent grooves corresponding with the ridges of the other valve. External surface covered with flexuous lines of growth. Shell-substance punctate in the inner layers. Type, Lyttonia nobilis, Waagen. Carboniferous. India and China. 314 PALEONTOLOGY OF NEW YORK. Gends OLDHAMINA, Waagen. 1883. 186S. BrUerophim, db Kominck. Quart. Jour. Qeol. Soc. London, vol. xii, ji. 8. 1880. TheckUa, Zhomatbr. Unters. Qber rhfit. Brachiopoden ; Beitr. zur Palaont. Oeaterreich- Unjrarn. I, p. 22. 1888. Oldhamina, Waaqkn. Pi-oductua-limestone Fossils ; Brachiopoda, pp. 403-409, pi. zxxi, figs. 1-9. Shells highly concavo-convex. Pedicle-valve subhemispherical ; apex incurved, at maturity covered by a callosity, as in Bellerophon; attached by cementation in early growth. Hinge- line short and straight, not interrupted in the middle ; below it lie well- developed teeth. Interior surface of the valve covered with diverging lateral ridges. FlO. 246. Fia. US. Fio. 247. Otdhamina dtcipient, de Koninck. FiK 249. The exterior of a pedicle-valTe with the shell partly exroliated. Fig. '246. Posterior view or the brachial valve; showing elevation and lobation or the cardinal process. Fig. 217. The interior of a pcdiole-valve; showing the median and lateral ridges. (Waaobn.) Brachial valve concave. Cardinal process inconspicuous, quadripartite at the summit ; continuous with a median ridge extending the entire length of the valve. Internal surface covered with divergent grooves corresponding to the ridges of the opposite valve. Exterior smooth or with numerous concentric lines of growth. T)^, Oldhamina decipiens, de Koninck. Carboniferous. India and China. Dr. Waagen has described the structure of these genera at great length, and from his investigations infers that the shells are not distantly related to BRACHIOPODA. 315 Thecidea and Pterophloios. If this be true, they constitute the only satisfac- torily known representatives of the family Thecidew^ in palaeozoic faunas. Kayser described, unier the name Leptodus Richthofeni, a species of Lyttonia from among the fossils collected by Richthofen in China; otherwise these genera are unknown outside of India. Genus RICHTHOFENI A, Kayser. 1881. 1863. Anomia, db Kosinck. Quarterly Journal Gteol. Soc. London, vol. xix, p. 6, pi. iv, figs. 7-9. 1863. Anojnia, db Koninck. Foss. Paleoz. de llnde, p. 18, pi. iii, figs. 7-9. 1881. Richthofenia, Katsbb. Zeilschr. derdeutsch. geolog. Gesellsch., vol. xxxiii, p. 351. 1882. Antnnia (Richthofenia), Waaqkn. Neues Jahrb. fur Mineral., vol. i, p. 115. 1883. Richthofenia, Waagbn. Records Gfeol. Survey of India, vol. xvi, pt. i, p. 12, pis. i, ii. 1883. Richthofenia, Katsbb. Richthofen'a China, vol. iv, p. 195, pi. xxiv, figs. 6-8. 1885. Ricfithnfgnia, WAAOEif. Productus-limestone Fossils; Brachiopoda, pp. 733-743, pi. Ixxxii, fi|^. 1 ; pi. Ixxxii A, figs. 1-4 ; pi. Ixxxiii, fig^. 1-19. These peculiar fossils, which bear a striking external resemblance to certain operculated corals, and present some suggestive similarities to the lamellibranchs FIO. M8. Fio. M9. Fig. 260. Pro. 251. Richthofenia Lawrenciana, de Koninck. Fig. 248 The exterior of llie two valves in articalation. Fig. 219. LongiluiliDUl section of the pedicle- valve; showing the interior cavity and the cellular shell suhstance. Fig, 2S0, The Interior of the pedicle-valve; showing the hinge-line and muscular scars. Fig. ai. The interior of the brachial valve. (Waagbn.) 316 PALEONTOLOGY OF NEW YORK. HiPPDRiTES and Radiolites, have been carefully elaborated by Waagen, who arrives at the conclusion that they are of brachiopodous nature, the normal brachiopod characters being somewhat obscured by their mode of growth. From the accompanying figures, taken from Waagen's illustration of the genus, it appears that the valves when well preserved show a distinct hing<^-line, faint articulating processes and muscular impressions, all more similar to the corre- sponding structures in the brachiopods, than to anything occurring among the corals or Rudista. If this evidence of the brachiopodous nature of these fossils prove convincing, the remarkable development of the cellular testaceous tissue of the pedicle-valve which produces the striking external resemblance to a coral, is certainly a no more extreme deviation from the brachiopod-type than are such bodies as Hippurites, Capkotina, Radiolites, etc., from the type of lamellibranchiate structure. The shells were evidently attached by solid fixation at the apex of the pedicle-valve, and this attachment strengthened by the epi thecal rootlets extending downward from the walls of the valve, simi- lar to those in Omphyma and other corals. In regard to the taxonomic position of Richthofenia, Waagen says : " To sum up all that has been said on the affinities of Richthofenia, we have found that these shells most probably belong to the Brachiopoda, but that they constitute so strong a group within this class, that though they may be assignable to the Arthropomata, yet they can not be placed immediately in the vicinity of any known group. They show on the one hand external affinities to the corals, and on the other structural affinities to the Pelecypoda. This conflicting evidence alone will justify my considering them at least as a proper sub-order, for which I introduce the name of ' Coralliopsida.' " Two species of this genus have been described, the Anomia Lawrenciana, de Koninck, and R. Sinensis, Waagen. Both of them probably occur in the Car- boniferous beds of the Salt-Range of India, but the latter is the form upon which the genus was founded by Kayser, and was obtained from the upper Carboniferous rocks of Lo-Ping, China. BRACHIOPODA. 317 .SUPPLEMENTARY NOTE ON VITULINA. (See pp. 138-UI.) Since the printing of the pages of this Volume, embracing the spire-bearing brachiopods, attention has been directed by Professor H. S. Williams to the fact that the presence of calcified brachial supports in Vitulina was noted by him in his address before Section E of the American Association for the Advancement of Science, in 1892. (See American Geologist, volume x. No. 3, page 165. 1892.) The language used in this place is as follows : " The most striking evidence of the affinity of these several faunas was derived from the study of three rather abundant genera of brachiopods ; Leptocalia, Vitulina and Tropidoleptus, genera which 1 would describe as old-type genera for this Devonian period, i. e., preserving the form and general characteristics of the lower Silurian Orthida and Strophomenida, but assuming the later character of calcified brachial supports of the Terebratulas and Spiriferidce. This is the case for at least the first two genera, and Tropidoleptus possesses the punctate structure characteristic of the Terebratulas." If it was the author's intention to intimate, in these sentences, that Vitulina is possessed of calcified spirals, his meaning has been most successfully veiled, and the reader might quite as fairly infer that the genus was regarded as bearing a loop. Professor Williams has, however, kindly communicated some further details of this structure accompanied by a figure, drawn from memory, showing a multispiral cone directed toward the cardinal angle, and an elongate loop showing " what appeared evidence of a saddle and accessory lamella as in Athyris." The cones are actually paucispiral and directed toward the lateral slopes of the pedicle-valve, but as to the structure of the loop our specimen has furnished no satisfactory evidence. The presence of a highly developed saddle and accessory lamellae would be surprising if true, and indeed quite incongru- ous with our present knowledge of related genera. December, 1893. BRACHIOPODA. 319 S U M ^I A R Y. THE EVOLUTION OF THE GENERA OF THE PAL^-OZOIC BRACHIOPODA. At the conclusion of the discussions upon the Inarticulate palaeozoic genera, some inferences were drawn as to the phylogeny and derivation of the more conspicuous types of inarticulate structure (Part I, pp. 161-170). At that time it had become evident that the variation in the form, position and mode of enclosure of the pedicle-passage affords a more satisfactory index of lines of progress and development, and gives a more lucid and reliable conception of the rise and decline of brachiopod genera, than the modifications in any other single character or association of characters. Previous writers have usually ascribed a high value to the disposition of the muscular scars upon the inner surface of the valves, the form of the genito- vascular sinuses, the configuration and degree of calcification of the brachia. The last of these must still be regarded as having a significance inferior in importance only to the mode of enclosure of the pedicle; but to the other features mentioned our present knowledge accords a less value in classification. By this is meant that the muscular system, the disposition and interrelations of the separate muscular bands, adheres closely to a standard type of expres- sion throughout the Class. This is especially true of the Articulate genera, where, from beginning to end, no radical modification of the type, in this respect, is effected. It is less true, perhaps, in the more highly specialized and more complicated muscular structures of the inarticulates, a group in which our knowledge of the fossil representatives is not altogether satisfactory on account of the tenuity and ready destructibility of the shells. It is quite natural to find in such a highly organized group the possibility of variation more frequently manifested. The opinion expressed in the " Conclusion " to the Brachiopoda Inarticulata, that the " feature of paramount importance " in dealing with the evolution of 320 PALEONTOLOGY OF NEW YORK. the palaeozoic brachiopodous genera " will be found in the character of the pedicle-passage" (p. 161),* its conformation and accessories, has been substan- tiated by all the later investigations of this work,f and is still maintained as the true basis of classification. It is not the present purpose to recapitulate at any length the substance of the deductions already set forth in regard to the Inarticulate genera. The views expressed have not been materially modified ; but during the interval since their publication an extraordinary interest has been manifested in the study of the Brachiopoda both recent and fossil, especially in France, Austria and America, and the additions thereby made to our knowledge invite special attention. LiNOULA has been shown to be a comprehensive type, not existent in pri- mordial faunas. As yet it is impossible to indicate any difference of generic importance between the Lingula of the Lower Silurian and that of existing seas. Its elongate form is not primitive, and its complicated muscular system is indicative of an advanced stage of progress. We may therefore look for the precursors of this type of structure among the less elongate (Lingulella) and more orbicular genera (Obolus, Obolella). In the diagrammatic scheme of the derivation of Lingula, given upon page 164 of Part I, Lingulella and Obolella are represented as divergent from some unknown earlier inceptive stock, whose existence, represented by a mark of interrogation, was deemed probable from the comparative study of these genera. Such an inceptive form would presumptively be wholly elementary in its contour, outline and structure of pedicle-opening, and, in fact, be little more than an amplification of the infantile condition in its descendants. It has since been observed by Beecher *lt is pi^)i>er to explain in this place, that though the title-page to Volume VIII, Part I, beai-s the date of 1892, the pages relating to the Inahticdlata, including the concluding chapter referied to, had been completed and printed in .luly, 1890. Certain of these (pp. 120-100), i-elaling to the structure and devel- opment of the i)edicle-pa8sage in Orbicdloidba, Schizocrania, Trkmatis, etc., were reset and issued sepa- rately at that date, with lithographic plates (IV B and IV k), and this piinted excerpt was distributed among students of the brachiopoda aa well us to the general scientific public. t The subordinal classification of the Brachiopoda introduced by Waaokn (ISSS-lSSi)) was based to some extent \i\wn the conformation of the pedicle-passage. The phyletic value of variations in this structui-e was first clearly indicated by Kugenb Dhslohqcuamps, and has been subsequently elaborated by several writers. BRACHIOPODA. 321 that the embryonic shell or protoconch (protegulum) of the brachiopod is " semi- circular or semi-elliptical in outline, with a straight or arcuate hinge-line, and no hinge-area. A slight posterior gaping is produced by the pedicle-valve being usually more convex than the brachial."* It appears, furthermore, to be composed of corneous, impunctate shell-tissue. The same investigator finds that the species described by Billings as Obolus Labradoricus, from a horizon at L'Anse au Loup, now regarded as Lower Cambrian, and subsequently identified by Walcott, at the same horizon at Swanton, Vermont,f is the nearest approach of the adult brachiopod to the simple type of the protoconch ; a semicircular corneous shell, with gaping cardinal margins. This shell has been distinguished by the generic term Paterina. There are, undoubtedly, other brachiopodous shells of obolelloid type that are quite as ancient as Paterina ; still the latter exemplifies the line along which the development of more complicated forms has proceeded, and it is in all respects the simplest known brachiopod. Paterina is an embodiment of the predicted ancestor of the linguloids and obolelloids, and, with our present knowledge, it appears to be the radicle of all the brachiopoda, both inarticulate and articulate. The departure from Lingula, through Lingdlops and Lingulasma toTaiMERELLA, by the progressive development of the vaulted muscular platform (see Part I, pp. 46, 165, plates i, ii, iva) is confirmed by evidence which is unusually complete and conclusive. Various intermediate stages have also been indicated by which a similar resultant is attained from the primitive obolelloids through Lakhmina, ♦ Bbbchkr ; Develo|Min;nt cif the Bracbiopuricu.i to require a new {lesig'ii.ilion, and has therefore termed it H'frfor- ghta Lal>radorica, var. Swantonent'u (See "Fauna of the Lower Camlman;" Tenth Ann. Rept. Director U. S. Geolosrical Survey, pi. Ixiv, fiffs 2, 3, dated 1890, issued 1892). Tht; fif^ures given in the work cited show that the var. SioanfonensU is in many respects the more primitive type, its valves being- the more nearly equiconvex, its sai-face characters simple concentric strije, while in the typical 0. Labraiinricwf, there is a conspicuous elevation of the umbo of the i>edicle-valve. a low median sinus on the l)rachial valve, as well as indications of rarlial plications about the beak ; all these are secondary characters which indicate progress towanl the true KuTOBr.iwA {K cingiilata). It sei-mi eviilent that the generic term Paterina was based upon the Swanton fossil, and hence, if the author'.s intentions are correctly interpreted, the type of the genus is Paterina SwantonenxU, Walcott As to the value to I)e ascribed to differences of shell-composi- tion within a given association of closely related genera, see reniai'ks under the discussion of Linqula and Tbimxrbi.la, and in the following pages. 822 PALEONTOLOGY OF NEW YORK. Elkania and Dinobolus (p. 28, plates iii, iv6). The chronogeny of the various elements is in full accord with the structural progress along both lines of deriva- tion; a single genus in this series, Lingulops, enduring in an unmodified condi- tion from faunas (Hudson River) antedating the appearance of Trimerella, to those in which Trimerella abounds (Niagara and Guelph dolomites). The entire group of linguloid and oboloid genera is bound together, as already shown, by the possession of an unenclosed marginal pedicle. They compose the Mesocaulia or Lingdlacea of Waagen (1883) (Atremata of Beecher, 1891).* The leading element in this group, Lingula, attained a static condition in early Silurian faunas ; the oscillations of the type were mainly confined to the preced- ing faunas ; those of later date are but slight departures in a few directions only. The combination termed Lingula having once become fixed, maintained itself with unexampled adjustment to changing conditions, even into the existing seas. Glossina, Dignomia, Barroisella and Tomasina, which represent early deviations along the line of its descent, embody no substantial variations, though the two last named (pp. 62, 65, plate ii) demonstrate the gradual assumption of articulating processes, a tendency which not infrequently makes itself apparent in this group where the pedicle-passage is wholly marginal. It is seen in Spondylobolus, and is sometimes faintly manifested in Obolus and Obolella ; in Trimerella there is occasionally a low cardinal process as shown by Davidson and King, and Got- land specimens of T. Lindstrami bear long subraarginal slotted ridges on the cardinal edges (Lindstrom). This mode of articulation, though not frequently seen in American specimens of Trimerella, is so much like that of Eichwaldia, and the general form of the shells of the two genera is so similar, that there is *To ensure {greater freedom of treatment and relief from the embarrassments of an inelastic classifica- tion, the discussions in these volumes have intentionally l)een left free of terms designating taxonomic values higher than genera. By provisionally declining allegiance to any prescribed formulas in classifica- tion, not only has the manner of treatment of the comprehensive material studied boen more natural, but the student will find himself less encumbered with artificial restrictions and freer from collisions with rock- ribbed party-walls, which, to use an old Scotch phrase, "are nane o' God's inakin'." It had, nevertheless, been the intention to summarize, in a tabulated form, at the close of this work, the broader relations of the genera discussed, not with any intention of introducing a series of new taxonomic terms, but to express succinctly these interrelations as they appear upon a review of the whole field of research. Such a table will be found at the close of this chapter. BRACHIOPODA. 323 a good excuse for associating them closely, as has been done by CEhlert, who places the latter genus among the Inarticulates Eichwaldia presents a pecu- liar modification of the pedicle-passage, and all its essential characters, acquired at an early Silurian age, were maintained to the close of the Upper Silurian without substantial variation. The origin of Eichwaldia is, at present, but a matter of conjecture; such resemblance as it bears to Trimerella, in its incip- ient articulating apparatus, seems to be only an instance of isomorphy. The second main division of the Inarticulate genera is composed of those in which the pedicle-aperture, in the immature stages or in primitive adult condi- tions, takes the form of a marginal incision of the pedicle-valve, but becomes enclosed in the shell-substance in later stages of growth. To this group Waagen applied the term Diacaulia* (or Discinacea, 1883), which, like Mesocaulia, is an admirable expression of the significance of the pedicle-passage. The name Neotremata was subsequently introduced by Beecher (1891) as an ordinal term for not only such forms as these, but also for those like Crania, of whose fixation by means of a pedicle there is yet no evidence. The mode of development and enclosure of the marginal incision in the genus Orbiccloidea has already been demonstrated,! and it has been shown that CEhlertella, Trematis and Schizocrania, which have an unenclosed aperture at maturity, are primitive conditions through which Orbiculoidea passes in the development of the individual. These primitive adult conditions occur in various faunas from the primordial (Discinolepis) to the Lower Carboniferous (CEhlertella), and while these genera might be conveniently associated on the basis of this feature, it is doubtful whether such grouping would be a natural one, or a proper expression of the relations of these forms to the various con- temporary mature types. * This name was originally printed Daikaulia, probably a typogrraphical error in the spelling' of the first gyllablep. WAAfiB.f , following' usage in the employment of the terms Ltopomata and Abthropomata as ordinal designations, subordinate only to the name of the Class, Brachiopoda, introduced Mesocaulia and Diacaulia as names of suborders. It is a purely arbitrary matter whether the former terms be regarded as designa- tions of orders or subclasses. They are, in either case, inferior in the first degree to the Class itself. Hence the fact that Waaob.v employed the latter terms as suborders is no ground for rejecting either of them for a later name having the same significance. t Volume VIII, Part I, loc. cU. 824 PALEONTOLOGY OF NEW YORK. Ill ACROTRETA, CONOTRETA, LiNNARSSONIA, AcROTHELE and IPHIUEA the pedicle- aperture is persistently located at the apex of the pedicle-valve. This group of genera is one of very early date, for the most part contemporaneous with Paterina, and the existing evidence would indicate that it was not directly ancestral to the line of Trem atis-Orbiculoidea (Discmw^). The incipient formation of an inter- nal foraminal tube is seen in several of these genera (Acrotreta, Acrothele, Linxaussonia), and this feature attains its maximum in the true Sipiionotreta of the Lower Silurian, where the foramen is still apical and the tube wholly internal. Hence Sirno.voTRETA appears to be a normal termination of this line of descent. Schizambon, in the comprehensive meaning of the term ascribed to it in this work, has the pedicle-passage superficial, and in such shells as Schizambon fissus, Kutorga, and var. Canadensis, Ami, the condition of this passage is perfectly analogous to that of Siphonotreta, the entire difference being in the enclosure of the latter. In Schizambon the fibers of the pedicle, extending through the foramen near the middle of the pedicle-valve, were directed toward the apex of that valve, and along the concave floor of the external pedicle-groove. The inner aperture of the pedicle-tube in Siphono- treta, corresponds to the " foramen " of Schizambon, and the outer aperture or true foramen of the former to the grooved umbo of the pedicle-valve in the latter. Hence in Schizambon, thus considered, there is no evidence of a prog- ress of the external aperture, or true foramen, anteriorly beyond the apex of the pedicle- valve. These two genera are but slight departures from the same type of structure, but it would appear that this deviation took place during primordial times, as the typical Schizambon (S. tijpicalis, Walcott) is a primordial fossil. The newly described genus, Trematobolus, Matthew* (T. insignis, Mat- thew, typej, appears to be another primordial representative of this structure, with the tubular enclosure of the pedicle more highly developed. Thus all these genera, from Acrothele to Schizambon and Siphonotreta, possess an apical foramen, and the development both of the internal tube and the corresponding extennal groove has been a gradual one. They represent termini of slightly divergent series ; consequently they may all be safely * Canadian Reconl of Science, January, 1893, pp. 277-279, figs. I a-d. BRACHIOPODA. 325 included under the old family designation introduced by Kutorga in 1848, SipBONOTRETIDjS Crania and its allies (Craniella, Pseudocrania, Pholidops) constitute a group in which there is, thus far, no satisfactory evidence of the existence of the pedicle, and we are left to the inference that this organ became atrophied at a very early growth-stage. The study of recent Cranias has not yet deter- mined this point, but this will probably be ultimately accomplished. At whatever stage of growth the pedicle was lost, we may infer that its disap- pearance, in Crania, and generally in Craniella, was directly followed by a solid fixation of the animal by the substance of one of the valves. In Pholidops there was no such cementation, but at a correspondingly early stage the shell became wholly independent. All these shells with central or subcentral beaks have an external resemblance to Orbiculoidea ; the formation of the secondary growth of the valves behind the apices or position of the protoconch, is a fur- ther substantial agreement with the Diacaulia as contrasted with the abbrevi- ated posterior peripheral shell-growth in the Mesocaulia (Lingula, Obolus). It is nevertheless to be observed that no trace of a former pedicle-slit, incision or perforation, is found on mature or immature shells, and it would be difficult to comprehend in what manner such an essential modification of the shell could be wholly concealed by later growth.* Were the pedicle marginal in primitive growth-stages, and subsequently atrophied, the obliteration of the marginal opening by later resorption and growth would be a readily intelligible process. There is, hence, in this default of evidence, a good reason to doubt the close affinities of Cranla and Pholidops to the Diacaulia. Present knowledge would seem to indicate that they were primarily of the type of the Mesocaulia, and that their resemblance to the Diacaulia is wholly of secondary growth.f * Quite early conditions of Crania siluriana aixl Craniella ffamiltoHiw, from 1.5 to .5 mm. in diameter, are fully cemented. Examjilea of Pholidops HamiltimuB, not above .5 mm. in diameter, give no indication of a [)edicle-])a8sage or sui-face characters not present in the adult. t Some species of Pholidops (P. arenaria, P. livgiiloidex) have a terminal submarginal apex ; and their resemblacice exteriorly to the oboloids is very striking. This is, however, no more than a i-eserablance, as they show, on the under side, the same mode of peripheral growth beneath the beak as the other forms of the genna in which the umbones are more nearly central. 326 PALEONTOLOGY OF NEW YORK Waaqen's term for this group, Gastropegmata (or Craniacea) may therefore prove to be equivalent to each of these other two divisions. The great gulf which has seemed to exist between the Inarticulate or Lyopomatous, and the Articulate or Arthropomatous divisions of the Class Brachiopoda ; those without teeth and those with teeth ; those with a largely corneous shell, and those whose shell is essentially calcareous, is not yet fully spanned at many points. These divisions were based upon the study of living brachiopods in which all the characteristic differences are pronounced and fixed. We naturally ex- pect to find, however, among the early brachiopods, in which the adjustment of the organism to its conditions was highly sensitive, that the oscillation and specialization of characters has been very rapid. The development of articulat- ing processes has already been noticed among the linguloids, in Barroisella, ToMASiNA and Trimerella, among the oboloids in Spondylobolcs, and among the siphonotretoids in Trematobolus. It is known that the shell of many inar- ticulates is almost wholly calcareous, as in the TniiiEitELLiDjE and all of the so- termed Gastropegmata. The alteration in the nature of the shell-substance from protoconch, or its exemplar, Paterina, which appears to be wholly or essentially corneous, to the typical articulate brachiopod, in which the corneous sub- stance is reduced to a thin epidermal film, is a gradual process whose various stages are well understood. In Obolella, Elkania, and the early forms of Lin- GULA, the deposition of calcareous salts in the shell was already advanced, these layers alternating with thinner layers of corneous substance. The gradual and eventual predominance of the calcareous shell-matter along both of these lines of development is seen in the ponderous Triraerellids of the later Silurian. The graduation of the corneous Paterina (Kutorgina Labradorica, var. Swanton- ensis) through Kutorgina Labradorica, and into the true calcareous Kutorginas (A', cingulata, K. Whitjieldi), is similar evidence. In Kutorgina Latourensis, Mat- thew described a minute tooth on either side of the pedicle-opening,* and it has been stated that K. cingulata shows faint traces of articulating processes at * lUustrations of the Fauna of the St. John Group, No. 3, p. 42. 1885. BRACHIOPODA. 327 or near the extremities of the cardinal line.* Such cases indicate, in the text- ure and composition of the shell, a direct passage from the most primitive inarticulate to the articulate type. In this feature only, the connection between the two divisions of the class is no closer or more clearly manifested than in the instances mentioned, but it has been shownf that Kittorgina cingulata may retain a pedicle-covering or external sheath, in fact a true deltidium bearing an apical perforation, like that in Clitambonites. A deltidium-like structure is highly developed or fully retained at maturity in Iphidea. This is evidence of the highest moment, and shows conclusively the line along which the clitambon- itoids and strophomenoids have been derived. It is an immediate departure from the primitive type of the brachiopod into the articulate subtype. Passage from the inarticulate to the articulate plan of structure was thus effected at a very early period ; indeed, almost at the outset of the history of the group. The continuance of the two types has since been that of diverging series, constantly widening the structural gap between them. We have no evidence that this cliasm has been bridged at any other point than near its source ; the inclinations from the one type toward the other, shown in the articulating processes of Bakroisella, Tomasina, etc., represent uncompleted accessory lines of development, which were abruptly terminated without accomplishing the full transition. Such forms have left no descendants, so far as known. Before entering upon a summary of the phyletic relations of the genera of the Articulata, it is important to apprehend the full significance of the modifi- cations here appearing in the structure of the pedicle-passage and the surfaces upon which the muscular bands are implanted ; in other words, the origin and development of the deltidium, the deltidial plates, and the spoon-shaped mus- cular platform, or spondylium, which may occur in either or both valves, and may be supported or not supported by a median septum. The deltidium and deltidial plates, though similar in function, are profoundly distinct, both in origin and structure. The former is primitive and funda- * Bebchkr, Amei-ican Journal of Science, voL xliv, p. 138. 1S92. t Bbbchkb, loc. elth>'rlain of a yoan; Jihjfnchonella. Tig, 266. The same, at a later stage, with two triangular deltaria. Fig. 167. Tho same, at coroplctcil growth of tlie tlcltarta. Figs. 263, i63. Dorsal and prolllc Tiows of Magellania HaracetUi showing n ol itngellania JUKOceru i showing the complete envelopment of the base of the pedicle by secondary expansions of the ventral mantle, which have formed the deltaria, as shown in flg. 268. (Beeciieb.) These plates may unite along the median line, obliterate the foramen, or even extinguish all trace of their original division, as frequently seen in Spirifer, Cyrtia and Cyrtina {pseudodeltidium), thus simulating in every respect the true deltidium ; though it is now evident that these and the deltidium are of funda- mentally different nature. These structures, then, become, at once, a most important basis of classification among the articulate Brachiopods. In this work the term spondylium has been applied to the spoon-shaped plate which, when present, is usually found in the pedicle-valve only, but among the pentameroids frequently occurs in both valves. It has become evident since the introduction of the term that these processes in the two valves, though * Bbbchbb, 2oc. cU. 332 PALEONTOLOGY OF NEW YORK. similur in Jispect, are similar neither in origin nor function, and it becomes necessary to modify the application of this term. Hence it is proposed to restrict the term spondylium to the plate existing in the pedicle-valve, and to the plates of the brachial valve, whether united or discrete, the name cruralium will be applied. The distinction of the parts is necessary to a proper appre- hension of their value. The spondylium is an area of muscular implantation. In its early or incipient condition it is evident that it originates from the convergence and coalescence of the dental lamelliE, and forms a receptacle for the proximal portion of the pedicle, and for the capsular or pedicle muscles. In Clitambonites and Pen- TAMERDS, where it attains its greatest development, it bears all the muscles of the valve, the central adductor, and the lateral diductor scars being often clearly defined, while the posterior portion of the plate is still reserved for the attach- ment of the pedicle, if functional. Considering this structure in its incipient condition, where, as in Orthis, it is represented only by the convergent dental plates which usually unite with, or rest upon the bottom of the valve, and enclose only the base of the pedicle and its Tuascles, it will be evident that the plate is actually but a modification of tlio original pedicle-sheath. It is, evidently, the inner moiety of this sheath surrounding the pedicle, which has become involved or enclosed by the growth of the pedicle-valve, and fur- ther modified by the development of articulating processes where it comes in contact with the brachial valve. It therefore follows, as a natural inference, that wherever the spondylium is present, whether in the incipient condition or in the more advanced stage of development in which it supports all the muscles of the valve, it is, or, at some period of growth, has been accompanied by the external portion of the sheath, which is termed the deltidium. Thus the spon- dylium appears to be but the complement of the deltidium, or the original plate formed upon the body of the embryo, and that portion of the adult shell to which the term deltidium has been applied, is the other part of the original or primitive deltidial plate or pedicle-sheath. Here again our terminology seems at fault and should be further adapted to the proper conception of these structures. Should the term prodeltidium be employed for the primitive body plate or the BRACHIOPODA. 333 pedicle-sheath in its entirety, we shall then have the terms spondijlium and delti- dium applied to corresponding and equivalent modified parts of this plate, the former internal, the latter external. The adult condition of the shell does not always furnish complete, and some- times not even suggestive evidence of the relations of the spondylium and deltidium. For example, in the genus Orthis and its various subdivisions, the delthyrium is almost always open at maturity and indeed all through the later growth-stages of the shell. The deltidium unquestionably existed at an early stage and has usually become resorbed long before evidences of maturity in other respects aie assumed; the spondylium, also, does not pass beyond a condition which makes the pedicle-cavity a clearly defined feature of the inte- rior. Tn more elementary or less modified orthoid structures like Billingsella, Protorthis, and the Orthis dcfleda and O. loricula (see Plate Va, figs. 30, 31), the deltidium is fully retained at maturity, while the spondylium remains in its condition of a simple pedicle-cavity. The coexistence of both features with a high degree of development, as in Clitamhonites, Polyt(echia, etc, indicates a more primitive condition than in Orthis, though in such cases the extension of the spondylium to such a degree as to carry all the muscular bands of the pedicle-valve must be regarded as a secondary modification of this organ. In Pentamerus and allied genera, where the spondylium attains its greatest de- velopment, the deltidium is usually lost, but when retained is very thin and has a concave exterior, a form doubtless largely due to the arching of the umbo of the pedicle-valve over the full, procumbent beak of the brachial valve. The spondylium occurs in various modified conditions ; in cases where the teeth are wholly without dental lamellae, or where such lamellae do not extend to the bottom of the valve, it seems necessary to regard them as instances of degeneracy or resorption of the primitive spondylium. As the growth, modifi- cation and disappearance of the differential parts of the prodeltidium do not progress pari passu, there will frequently be examples of one being retained when the other has disappeared. A remarkable illustration of this fact is afforded by the genus CAMAROPriORiA, which possesses a highly developed spon- 334 PALEONTOLOGY OF NEW YORK. dylium, while the deltidium has been resorbed and secondary deltidial plates or deltjiria formed about the pedicle-passage. Ill tlie fundamental division of the Articulata two groups will be recognized, one embracing those forms in which the prodeltidiura is represented by the deltidium and spondylium, one or both; the other a group in which the pro- deltidium has been fully modified, resorbed or replaced. The former group is equivalent to Waagen's suborder, Aphaneropeomata (1883), with the addition of Thecidea and its allies, and to Beecher'.s Protremata (1891), excepting the genus Tropidoleptcs. So deep-seated does this difference in these groups of genera appear, that examples of such combinations of primary and secondary conditions as shown by Camarophoria, are of the rarest occurrence. The spoon-shaped process of the brachial valve, which has been termed the cruralium, is a feature of more fugitive value. It is formed by the convergence or union of the crural plates, and it may rest upon the inner surface of the valve, or like the spondylium, be supported by a median septum. More often the crural plates, when highly developed, stand erect upon the valve and do not unite, but their position is highly variable, and it has been shown that in Pent- ameeus, CoxciiiDiUM, and their allied forms, the union of these plates is not of first importance as a generic character. When the crural plates extend to the bottom of the valve as distinct septa, they simply enclose an extension of the median incision of the hinge-plate. It has become evident, from a study of the hinge-plate, that the so-called visceral foramen which perforates it, and which is often present in Athyris, RensseljEria, Cryptonella, etc., is a remnant of this aperture, the remainder of the median opening having become filled by a testaceous secretion. There is every reason to believe that the visceral fora- men was actually traversed by the lower alimentary canal, and if this were true, then the deep and narrow median chamber bounded by the crural plates must also have enclosed the terminal portion of the intestine. Within it lie the elongate scars of the adductor muscles, and when the chamber is elevated by the completed formation of a cruralium, these scars are still within it, as in the case of the spondylium. It is therefore the morphic equivalent of the spondylium. Its supporting median septum, when present, is composed BRACHIOPODA. 335 of two lamellae, each representing one of the coalesced or adherent crural plates.* The unsupported convex internal plate or "shoe-lifter" in the pedicle-valve of Merista and Dicamara must be interpreted as an entirely different structure from the spondylium. It is not produced by convergent dental plates, but these, on the contrary, are divergent, the arched plate uniting its inner edges. Its origin and the reason of its existence are still obscure. The readiness with which the filling of the cavity between this plate and the outer wall of the valve separates from the shell, carrying with it the enclosing walls, leads to the suggestion that the " shoe-lifter " may be the innermost lamina of the shell separated from the rest of the valve and leaving it thinner in this region. This plate, upon its convex surface, bears the muscular bands, in whole or in part. In EiCHWALDiA it has been observed that the small internal plate of the pedicle- valve is probably a modified condition of the deltidium, as the pedicle passes beneath it, while the platform in AnLOCORHYNCHCS may prove to be wholly of muscular origin. The compound " shoe-lifter," divided by the median septum in the brachial valve of Dicamara, is like the corresponding plate n the pedicle-valve in hav- ing no connection with, or origin from the articulating apparatus. This plate is not a cruralium, and in precisely the same sense that the simple " shoe-lifter" is not a spondylium. Such cases as Merista and Dicamara are, therefore, not to be cited as examples of the concurrence of spondylium and cruralium, with the secondary condition of the pedicle-covering or deltarium, but are, rather, illustrations of the production of parts which may be similar in function in the mature condition, but are totally distinct in origin ; in other words, interesting instances of morphic equivalents. * In the (lentameroids the median septum of the pedicle-valve supporting the spondylium, is formed in a similar manner by a continuation and coalescence of the dental plates, and wherever the median support- ing septum exists in this gi-oup, it will probably be found to have this composition. Median and lateral septa, however, in the valves of \he Brachiopoda, have a highly diverse origin in different cases. In most instances, except where bearing spondylia, they are evidently of muscular origin and sui-faces of muscular attachment, as shown in SpiRiPBRtXA (see figure 42, page 53, and remarks in foot-note. Part I, p. 49) ; while in the Trimkrkludx they appear to be the residuum left by the resorption of a thick testaceous deposition Aboat and t>eneath the area of muscular insertion. 336 PALAEONTOLOGY OF NEW YORK. The cardinal area is a feature more generally developed among the forms in- cluded by Waagen under his term Aphaneropegmata (=Protremata, Beecher), that is, among forms possessing the deltidium, but it is very irregular in its occur- rence among all the articulate Brachiopoda. The genus Spirifer furnishes a most striking instance of its persistence in the deltarium-bearing shells ; its usual absence in Pentamerus .and Concuiuium serves to demonstrate that it is not an indispensable character of its group. It is probable that the existence of this area has little fundamental connexion with the condition of the pedicle-passage. It is a very palpable fact that there is a much more intimate relation between it and the general form of the shell; thus in the elongate shells, like the terebratuloids, meristoids, retzioids and the pentameroids for the most part, there is no such area present. Where the form of the shell is more generally transverse, as among the Ohtbidm, in Strophomena, Clitambonites, Derbya, Spirifer, etc., the area is highly developed. This area is a characteristic feature of all early deltidium-bearing species, and, where it manifests itself occasionally in one of these groups which has for the most part lost, or never developed this area, as in Porambonites, Gypidula and Pentamerella among the pentameroids, its appearance may be regarded as the resumption of a primitive or original character which was normal for that division of the Articulates in some period of its history. Similarly we meet with a cardinal area in an early rhynchonellid type, Orthorhynchula, and this is an evidence of the first significance as indicating the source from which the extensive group of the Rhynchonellas originated. These are shells which, at a very early period, assumed the deltarium or sec- ondary condition of the pedicle-covering. It would be presumptuous to assume that a single species of this great group developed a cardinal area solely from mechanical causes, such as obstructed growth on the posterior margins of the valves. Its presence seems, rather, to suggest the perpetuation of an ancestral character indicating that these modified shells have been derived from a more primitive condition in which the cardinal area was normal and, no doubt, accompanied by a deltidium. In the absence of further evidence such a char- acter is of much interest and importance. BRACHIOPODA. 337 Under the guidance of the structural features above considered, the main lines of derivation of the Articulate genera are more readily apprehended. The earliest known representatives of a given group of genera are not always the most primitive in structure. In the instance cited in the pre- ceding paragraph, Orthorhynchula Linneyi is perhaps, by itself considered, the closest expression of the fundamental stock from which the rliynchonellids have been derived, but it is by no means the earliest of the group. It is known only in the latest fauna of the Lower Silurian, while in the earlier faunas, Protorhyn CHA, RiiYNCHOTREMA and Camakot(echia have attained an abundant development. Orthorhynchula either represents a resumption of the primitive type, subsequent to such modifications as appear in the earlier rhynchonelloid genera, or a continuance of that type, Avithout modification, through preexist- ing forms as yet unknown. Such instances could be multiplied, as facts of similar import are constantly recurring, and a careful consideration of the stage of development or decline of each separate and individual organ is requisite to determine how far the organism in question is a direct or modified outcome of the fundamental type ; or a degenerate or senile relapse, after modification, to phyletic immaturity. The most elementary structure, then, observable among the Articulate Brachiopods, is the combination of the deltidium with a distinct pedicle-cavity, whose anterior margins are not free, and whose lateral walls or dental lamellae are not highly developed ; these features being accompanied by gently and un- equally biconvex valves, well defined cardinal areas and elongate hinge-line ; producing, in effect, a generally orthoid expression both of interior and exte- rior. This is the condition of Billingsella of the Cambrian, Orthis loricula and 0. dejleda of the Trenton group, and 0. ? laurcniina of the Hudson River fauna, and it is continued without essential modification, except in the gradual contraction of the pedicle-cavity and deltidium, into Strophomena of the Silu- rian, its allies and successors, Orthothetes of the Devonian, and Derbya of the Carboniferous, Hipparionyx, Triplegia, Streptorhynchus, etc., into Lept^na, Rafinesqoina, Stropheouonta, Plectambonites, Choxetes and Productus. 338 PALEONTOLOGY OF NEW YORK. The tendency to contract the pedicle-cavity and deltidium presents its extreme manifestation in the Devonian forms of Stropheodonta, Strophonella and Leptostrophia, where it has become almost, and sometimes quite obliter- ated, and the entire pedicle and umbonal cavity filled with testaceous secretions. Such filling can occur only in a discarded and useless space, after the pedicle has ceased to be functional. A morphological consideration of much importance presents itself here, as well as in many other groups of genera where the shells attain groat size. The evidence is very direct from the study of the structural features as given above, that the entire muscular system on the ventral side of the body, is, in primitive forms, inserted upon the base of the pedicle-cavity. This is apparent from a study of such a shell as Orthis callacUs, where it is per- fectly clear that no muscular bands were attached to the pedicle-valve outside the limits of this strong and condensed posterior area, which is but a sessile spondylium. The contraction of this pedicle-cavity is accompanied by (whether in relation of ciuse to effect can not be stated) a diffusiou of the area of mus- cular attachment, and when the shells are large, as in Stropiiome.va, Rafines- QUiNA, Stropheodonta, Orthothetes, Derbya, etc., the necessity for powerful muscles, or some similar cause, magnifies this expansion of the muscular area until the original contents of the pedicle-cavity may be represented by enorm- ous muscles whose scars extend almost to the anterior margin of the valve, as in IIiPPARiONYX and Rhipidomella. In this great group of genera there are two types of contour, one, as in LepTjEna, being normally convexo-concave, that is, with the pedicle-valve con- vex and the brachial valve parallel to it and concave ; the other, as in Stro- PHOMENA, having this contour reversed, the pedicle-valve at first convex, but subsequently and through all later growth-stages concave, while the brachial valve becomes correspondingly convex. In both cases, as in other brachiopods, the primitive and post-embryonic valves are both convex. The peculiar reversal of contour, which is never more extremely manifested than in this group, but nevertheless occurs in other genera, such as Atrypa, many Rhynchonellas, etc., is a purely secondary condition. Its causes have not been fully investigated, but an unequal peripheral growth of the two valves, arising from inequality in BRACHIOPODA. 339 the size of the ventral and dorsal mantle lobes, seems to be a partial if not sufficient explanation of its existence. As either the presence or absence of this reversal is a normal secondary condition, it is not possible to give it great weight in a broader grouping of the genera, for we find that Strophonella is but a reversed Stropheodonta, passing through similar phases ; Amphistrophia is a reversed Brachyprion, both existing in faunas of the same age, and Stro- PHOMENA is a reversed Rafinesquina, both similarly coexistent. With this presentation of the subject it seems neither necessary nor desirable to propose any broad division of this group of genera. In 1846 King proposed to embrace Strophomena and its allies, in the family STJtoPHOMEmDjs. The large number of generic values allied to Strophomena, which have been deter- mined since that date, make this comprehensive family divisible ad libitum, sed non in majorem Dei gloriam. The calcareous fixation of the pedicle-valve to extraneous bodies after the closure of the pedicle-passage and atrophy of the pedicle itself, is repeatedly manifested by these shells. This, as already shown, is a pre-adult condition in Orthothetes, Derbya and Streptorhynchus, the shell becoming wholly free before full growth was attained ; but in LEPTiENiscA and Davidsonia the attach- ment was maintained throughout the later existence of the shell. The impres ions left by the spiral arms upon the interior of the valves in Davidsonia and Lept^enisca, and also observed by Davidson in specimens of Rafinesquina Jukesi and Leptccna rhombmdalis, show a complete correspondence in the direction and curvature of the coil.e, and we are left to infer that other members of the Strophvuenid^ were in agreement with this .structure, and, hence, that the arms in their uncalcified condition approached nearer the cal- cified spirals of KoNiNCKiAiD^ (C(EL0SPiRA, Koninckinia, etc.) than to any other group. The condition of the pedicle-passage possessed by these shells is maintained by Chonetes and Productus, without great modification in other respects. Chonetes possesses a marginal row of strong cardinal spines or tubes communi- cating with the internal cavity of the valves. Yet we are acquainted with forms (e. g., Anoplia nudeata) in which these spine-tubes do not manifest them- 340 PALEONTOLOGY OF NEW YORK. pelves externally. Prodcctos is normally covered with spines on one or both valves, but there are some species which possess none. The cardinal area, deltidium and teeth, which are retained in Chonetes, Productella, Strophalo- siA and AoLOSTEGES, become wholly obliterated in the direct line of productoid development. In all these forms the " reniform impressions " retained on the inner surface of the brachial valve, are evidence of fleshy brachia possessing a similar curvature to those of the Strophomenid^ This group of genera has long been designated by the family name Pnonvcrw^ introduced by Gray in 1840, though, in correlating the various divisions of Waagen's proposed group, Aphaneropegmata, there would be excellent reason for considering the chonetids and productids components of a subfamily infe- rior in value to the Strophouekid^ and equivalent to the divisions Orthothetiruz, Waagen, 1884, and Rafinesquinince, Schuchert (emendatus), 1893.* Returning to the point of departure, we shall find that in the genus Orthis, which in its broadest significance is tantamount to the family Ort/iid^, Wood- ward, 1852, since the elimination of several heterogenous branches, the delti- dium was resorbed at an early stage of growth, leaving the delthyriura a wide, uncovered aperture during all the later stages of existence. The pedicle in this group of shells was undoubtedly large and vigorously functional through- out all mature conditions, as it is of very rare occurrence that any secretions of calcareous matter are found in the apex of the delthyrium, such as are frequently observed in mature and senile conditions of Spirifer. The sharp delimitation of the pedicle-cavity containing all the muscular scars of the pedicle-valve, which occurs in the earlier forms (those of Orthis in its restricted meaning, such as O. callacUs, 0. costalis, etc.) is maintained in all the numerous subdivisions of the genus, with the exception of Rhipidomella in. which there is a great expan- sion of the muscular scars, similar to that in the Strophouenid^ and to which reference has just been made. Otherwise the sessile condition of the spondy- lium is not modified throughout the entire history of this group. The elevation of the spondylioid plate, or the base of the pedicle-cavity, into a true spondylium, is a phenomenon of equally early age to the two conditions * Ameiican Geologist, vol. xi, p. 1S3. BRACHIOPODA. 34i already discussed. It appears in a highly developed state in conjunction with the unmodified deltidiuin, first in Pkotorthis, of the Cambrian, then in PoLYTCECHiA, Stntbophia, Clitambonites and ScENiDiuM, of the early and later Silurian and of the Devonian. A parallel line of development is exhibited by spondylium-bearing forms in which the deltidium disappeared at a very early period, and the shells possess a trihedral, generally coarsely plicated and decidedly rhynchonelloid exterior. It seems highly probable that this line was differentiated in the early Cambrian, as indications of this structure are observable in some primordial species, as Camarella ? minor, Walcott, and Stricklandinin ? Balcletchensis, Davidson ; in the Silurian it is represented by Camarella and Parastrophia ; also by the more rotund and more finely plicate shells, Anastrophia, Porambonites, Lycophoria and NoETLtNGH. The last-named genera are not homogeneous with the others in the phases of development which they represent, all of them retaining the cardinal areas more or less distinctly, while Lycophoria and Noetlingia also possess a cardinal process in the brachial valve. The presence of the cardinal area in such early structures must be regarded as a retention, rather than a resumption of a primitive character. Whatever may be the oscillation in form and the variation in secondary characters presented by Camarella, Parastrophia and their allies, present evi- dence indicates that they must be regarded as the genetic precursors, as they are the secular precedents of the great group of true pentameroids (Pentamerus, Capellinia, Conchidium, Barranuella, Sieberella, Pextamerella, Gypidula, Stricklandinia, Amphiqenia) ; and, indeed, the last of these pentameroids, Cam- AROPHORIA, of the Carboniferous and Permian faunas, is an exemplification of, and in fiict a return to the rhynchonelloid exterior and the camarellid aspect, witli the addition of deltaria in the delthyrium. While considering in detail the pentameroid genera mentioned above, it has been shown that in certain of them, as Pentamerus and Conchidium, a true deltidium is often retained, though it is a fragile structure rendered concave by the arclied growth of the umbones of the valves, and is generally absent. In others, as Gypidula and Pentamerella, there are occasionally evidences of lat- 342 PALEONTOLOGY OF NEW YORK. eral, erect or convex growths upon the margins of the delthyriura, which may be interpreted either as remnants of a resorbed convex delti<5. Obthidiom, Hall, 1892. Debbya, Waagen, 1884. Stbophomena, Rafinesque (de Blain- Meekella, White and St. John, 1868. ville), 1825. Streptoehynchus, King, 1850. • In employing' an the fundamental divisional distinction in the Articulata, the presence of the deltidium or deltidial plates, the term Protrkmata, better than any other, covers those gfenera in which the primitive pedicle-covering is rei)resenteil by either the deltidiimi, the spondylium, or both. tMr. SciicciiKRT includes nnder this family term two genera, KuTORCiyA and Schizopholis, which have asiially been regarded as belonging to the inarticulate sub-class. The reasons for installation of these as the elementary family of the Articulata are given elsewhere. 354 PALEONTOLOGY OF NEW YORK. ffTJiOPHOMENIDJJi—Oontinued. Orthothetes, Fischer de Waldheim, Triplegia, Hall, 1858. 1830. Dicraniscus, Meek, 1872. HiPPARioNTX, Vanuxem, 1842. Mimdlus, Barrande, 1879. Katserella, Hall, 1892. Streptis, Davidson, 1881. Fakilt LEPTAiNinjE. Lept-ena, Dalman, 1828. Strophonella, Hall, 1879. Leptagonia, McCoy, 1844. Amphistrophia, Hall, 1892. Rafinesquina, Hall, 1892. Leptella, Hall, 1892. Stropheodonta, Hall, 1852. Plectambonites, Pander, 1830. Brachyprion, Shaler, 1865. Christiania, Hall, 1892. DoDViLLiNA, (Ehlert, 1887. Lept^enisca, Beecher, 1890. Leptostrophia, Hall, 1892. Davidsonia, Bouchard, 1847. Pholidostrophia, Hall, 1892. Family CHONETID^m. Chonetes, Fischer de Waldheim, 1837. Chonetina, Krotow, 1888 Anoplia, Hall, 1892. Chonostrophia, Hall, 1892. Chonetella, Waagen, 1884. Chonopectus, Hall, 1892. Family PRODVCTID^^ Gray. Strophalosia, King, 1844. Productella, Hall, 1867. Orthothrix, Geinitz, 1847. Productus, Hall, 1867. Leptanalosia, King, 1845. Marginifera, Waagen, 1884. Daviesiella, Waagen, 1884. Proboscidella, (Ehlert, 1887. AuLOSTKGES, von Helmersen, 1847. Ethbridqina, (Ehlert, 1887. Family THEOIDIID^, Gray. Lyttonia, Waagen, 1883. Oldhamina, Waagen, 1883. Family RICHTHOFENID^ Waaqbn. RiCHTHOFENiA, Waagen, 1883. BRACHIOPODA. 355 Family BILLINQSELLIDM Schuchbrt. BiLLINGSELLA,* Hall, 1892. Family CLITAMBONITID.'E, N. H. Winchell and Schdchbbt. Protorthis, Hall, 1892. Hemipronites, Pander, 1830. PoLYKECHiA, Hall, 1892. Orthisina, d'Orbigny, 1847. Clitambonites, Pander, 1830. Scenidium, Hall, 1860. Pronites, Pander, 1830. Mystrophora, Kayser, 1871. Gonambonites, Pander, 1830. Family STRICKLANDINIID^. Syntrophia, Hall, 1892. Stricklandinia, Billings, 1859. Family CAMARELLID^. Camarella, Billings, 1859. Porambonites, Pander, 1830. Parastrophia, Hall, 1893. Isorhynchus, King, 1850. Anastrophia, Hall, 1879. Noetlingia, Hall, 1892. Brachymerus, Shaler, 1865. Lycophoria, Lahusen, 1885. (?) Branconia, Gagel, 1890. Camarophoria, King, 1846. Camarophorella, Hall, 1893. Family PENTAMERID^. CoNCHiDiUM, Linn^, 1753. Sieberella, (Ehlert, 1887. Gypidia, Dalman, 1828. Capellinia, Hall, 1893. Antirhynchonella, Quenstedt, 1871. Pentamerella, Hall, 1867. Zdimir, Barrande, 1879. Gypidula, Hall, 1867. Pentamerus, Sowerby, 1813. Amphigenia, Hall, 1867. Barrandella, Hall, 1893. * The genus Billiitosblla, in correspondence with its early geological age, presents an elementary structural aspect indicating that it may have served as a point of departure for the Obibid^ and STMOraOMMllIDM. 356 PALEONTOLOGY OF NEW YORK. Order Telotremata, Beecher. Sub-order Rostracea, Schuchert. Familt RHYNCHONELLID^ Gray. Protorhyncha, Hall, 1893. Orthorhynchula, Hall, 1893. Rhynchotrema, Hall, 1860. Rhynchotreta, Hall, 1879. Stenoschisma, Conrad, 1839 Camarotcechia, Hall, 1893. LioRHYNCHUs, Hall, 1860. WiLSONiA, (Quenstedt) Kayser, 1871. Uncindlus, Bayle, 1878. Uncinclina, Bayle, 1878. Hypothyris, (McCoy) King, 1850. PoGNAx, Hall, 1893. Eatonia, Hall, 1857. Cyclorhina, Hall, 1893. Terebratuloidea, Waagen, 1883. Rhynchopora, King, 1856. Rhynchonella, Fischer de Waldheim, 1809. Sub-order Ancylobrachia, Gray. Familt CENTRONELLID^ VfAxaRS. Rensselaeria, Hall, 1859. Beachia, Hall, 1893. Newberria, Hall, 1891. Ce.vtronella, Billings, 1859. Oriskania, Hall, 1893. Selenella, Hall, 1893. Romingerina, Hall, 1893. Trigeria, Bayle, 1875. (?) Notothyris, Waagen, 1882. ScAPHioccELiA, Whitfield, 1891. Megalanteris, Suess, 1855. (?) Enantiosphen, Whidborne, 1893. Family STRINQOCEPHALID^ Dall. Strinoocephalus, Defrance, 1827. Cryptonella, Hall, 1861, EuNELLA, Hall, 1893. Harttina, Hall, 1893. DiELASMA, King, 1859. Family TEREBRATULIDM Call. Cran^na, Hall, 1893. DiELASMiNA, Waagen, 1882. Hemiptychina, Waagen, 1882. Beecheria, Hall, 1893. Epithyris, King. 1850. (?) Cryptacanthia, White and St. John, 1867. BRACHIOPODA. 357 Family TEREBRATELLIDM Kmo. Tropidoleptus, Hall, 1857. Sub-order Helicopegmata, or Spiriferacea, Waagen. Family ATRYPIDJE, Ball. Hallina, N. H. Winchell and Schuchert, Catazyga, Hall, 1893. 1892. Glassia, Davidson, 1882. Protozyga, Hall, 1893. Atrypina, Hall, 1893. (?) Cyclospira, Hall, 1893. (?) Clintonella, Hall, 1893. Zygospira, Hall, 1862. Atrypa, Dalman, 1828. Anazxjga, Davidson, 1882. Karpinskia, Tschernyschew, 1885. ORTHONOMiEA, Hall, 1858. Gruenewaldtia, Tschernyschew, 1885 FAJcaT SPIRIFERINID^ Davidson. Cyrtina, Davidson, 1858. Spiriferina, d'Orbigny, 1847. Family SPIRIFERIDJE, Kino. Spirifer, Sowerby, 1815. Martini A, McCoy, 1844. Trigonotreta, Koenig, 1825. Martiniopsis, Waagen, 1883. Brachythyris, McCoy, 1844. Cyrtia, Dalman, 1828. Fusella, McCoy, 1844. Syringothyris, A. Winchell, 1863, Choristites, Fischer deWaldheim, 1825. Amboc(elia, Hall, 1860. Delthyris, Dalman, 1828. Metaplasia, Hall, 1893. Reticolaria, McCoy, 1844. Verneuilia, Hall, 1893. Family NUCLEOSPIRID^ Davidson. Ndcleospira, Hall, 1858. Whitfieldella, Hall, 1893. Dayia, Davidson, 1882. Hyattella, Hall, 1893. Hindella, Davidson, 1882. (?) Camarospira, Hall, 1893. Familt CCEL08PIRIDJE. Anoplotheca, Sandberger, 1856, Leptoccelia, Hall, 1859. Bx^da, Davidson, 1882. (?) Anabaia, Clarke, 1893, C(elospira, Hall, 1863. 868 PALEONTOLOGY OF NEW YORK. Family JiETZTTD^. Rhtnchospira, Hall, 1859. Retzia, King, 1850. HoMCEOSPiRA, Hall, 1893. Uncinella, Waagen, 1883. Pttchospira, Hall, 1893. Eumetria, Hall, 1864. Trematospira, Hall, 1857. Acambona, White, 1862. Parazyga, Hall, 1893. Hustedia, Hall, 1893. Faiult UNCITID^ Waaohn. Uncites, Defrance, 1825. Family MBRISTELLIDJR. Waaqbn. Mebista, Suess, 1851. Charionella, Billings, 1861. Camarium, Hall, 1859. (?) Pentagonia, Cozzens, 1846. DicAMARA, Hall, 1893. Goniocalia, Hall, 1861. Meristella, Hall, 1860. Family ATHTRID^ Waaqbn. Meristina, Hall, 1867. Cliothyris, King, 1850. Whitfieldia, Davidson, 1882. Actinoconchus, McCoy, 1844 Glassina, Hall, 1893. Seminula, McCoy, 1844. Athyris, McCoy, 1844. Spirigerella, Waagen, 1883. Sptrtgera, d'Orbigny, 1847. Kayseeia, Davidson, 1882. INCERTJE 8EDIS. EiCHWALDiA, Billings, 1858. Aulacorhynchus, Dittmar, 1871. Didyonella, Hall, 1867. Jsogrcmwa, Meek and Worthen,1873. DESCRIPTIONS OF NEW SPECIES FIGURED IN VOLUME VIII, PART II. ObTHIS ? GLYPTA, Sp. nOV. PLATE LTXXIV, PIGS. 8, 9. Shell small, transverse, with long, straight hinge, making the greatest diam- eter of the shell , short along the median axis ; marginal outline transversely subelliptical Pedicle-valve with a broad and low median sinus and generally depressed surface The exterior bears from twelve to sixteen low, flat plica- tions, separated by narrow sulci, and sometimes with a fine groove on the sur- face of each. These extend from apex to margins, and are crossed by fine, undulating, subconcentric lines apparently in two oblique sets, producing a peculiarly reticulated or wavy surface similar to that occurring in the Swedish Silurian species, 0. /Mvent, Lindstrbm The muscular area of the pedicle valve is small. Length of an average pedicle-valve, 12 mm. ; width, 18 mm. Niagara dolomites. Near Milwaukee, Wisconsin. Stbophonella costatula, sp. nov. PLATE LXXXIV, FIGS. IS, 16. Shell subsemicircular in outline ; hinge-line straight or slightly arched ; sur- face depressed concavo-convex. Pedicle-valve elevated at the beak, becoming rapidly depressed anteriorly, the median depression continued upon the short linguiform extension at the anterior margin. Corresponding to this depression is a broad anterior fold on the opposite valve. The surface of both valves is covered with a few coarse, round, sharply elevated ribs, which rapidly bifurcate or multiply by implanta- 360 PALEONTOLOGY OF NEW YORK. tion. These are more or less irregular or sinuous, elevated at the concentric varices and crossed by faint concentric lines. The typical example has a length of 21 mm. and a width on the hinge of 24 mm. Niagara group. Louisville, Kentucky. Plectambonites pbodccta, sp. nov. PLATE T.TYTTV, FIQS. 2S, 24, 25. The original of this species is an internal cast of the pedicle-valve, with short, straight hinge ; rather narrow, depressed umbo, the shell becoming highly convex and greatly produced anteriorly. The sides of the valve are somewhat appressed medially and the anterior margin slightly expanded and suboval in outline. The cast shows the impression of short, divergent dental plates and a moderately broad muscular impression. The width of the shell on the hinge is 10 mm.; its length, 23 mm.; its convexity from the posterior margin, 8 ram.; from the anterior margin, 28 mm. Niagara dolomites. Yellow Springs, Ohio. Spibifer cbispatus, sp. nov. PLATE XXXVI, FIGS. 9, 10. Shell small, with moderately high, incurved area, scarcely extended on the hinge ; well-developed median fold and sinus, and three coarse plications on each lateral slope. The surface is covered by conspicuous concentric lamellae. Niagara group. Maryland. Spirifer Canandaigu.*!, sp. nov. PLATE XXXVn, FIGS. 23, 84, 25. Shells of rather small size, having somewhat the aspect of an elongate and umbonate &. Jimbnatus. Umbo of pedicle- valve prominent, narrow and closely incurved at the apex. Hinge-line quite short, cardinal area small, incurved. Median sinus deep, produced on the anterior margin, its anterior width being BRACHIOPODA. 361 nearly equal to the length of the hinge. On each lateral slope are from two to four low radial undulations or plications, all of which are sharply defined at the umbones. Surface covered with very fine, closely crowded concentric lines which are granulous and were originally fimbriate. Length of typical speci- men, 21 mm. ; greatest width, 22 mm. ; length of hinge, 10 mm. Hamilton group. Centerfield and Canandaigua Lake, N. Y. Spirifeb mucbonatus, Conrad, var. posterus, var. nov. PLATE XXXIV, FIGS. 27-81 A late variety of the typical Hamilton form, characterized by its small size, usually narrow bodies and acuminate cardinal extremities. Chemung group. Tompkins county, N. Y. Spirifeb disjunctcs, Sowerby, var. sulcifer, var. nov. plate: XXX, FIG. 16. This variety is distinguished by the sharply defined median sulcus on the folds of the brachial valve. It has heretofore been embraced within the limits of »SI. disjundus, but the character referred to appears to be persistent. Chemung group. Near Olean, N. Y. Spirifer Williamsi, sp. nov. PLATE XXXVII, FIGS. 20, 21, 22. Shells of the form of Spirifer increbescens, Hall, and varying but little in size. Median fold and sinus well developed. The latter bearing usually three, some- times four plications, finer than those on the lateral slopes. Of these the me- dian plication is generally the strongest. This, however, is not always the case, the arrangement of these plications being frequently quite irregular. The median fold generally bears a median groove and one lateral plication on each side. On each lateral slope of the shell are seven or eight plications. A normal example measures: Length, 15 mm. ; width on hinge, 24 mm. Chemung group. Allegany county, N. Y. 362 PALEONTOLOGY OF NEW YORK. Spirifkr Newberbti, Hall. 1883. (See Report State Oeologrist for 1882, Plate (xxxi) S6, Fig^s. 9, 10). PLATE XXXI, KIGS. 9, 10. Shell moderately large, with sharp cardinal angles. Surface plication con- sisting of numerous fine simple or duplicate ribs which cover the median fold. On each lateral slope there are twenty-five to thirty of these plications. The plications and the grooves between them are covered with fine radiating lines. Waverly group. Ohio. Ctbtia radians, sp. nov. PLATES XXV^^, FIGS. 4, 5,80,84; XXXIX, FIG. S3. The typical form is of medium size, with high area, incurved umbo and gen- eral cyrtiniform aspect. Its outer surface is characterized by an absence of plications and fine radial striae. Median fold and sinus well developed. Clinton group. Rochester, N. Y. An allied but larger form, here referred to this species, occurs in the Niagara dolomites, near Milwaukee, Wisconsin. Cyrtina umbonata. Hall, var. Alpenensis, var. nov. PLATE XXVm, FIGS, lft-20. Cyrtina umbonata. Hall, from the original locality in Iowa, is a small shell, often obscurely plicated ; this variety possesses the contour of C. umbonata, but is a larger and more robust shell with broad and well-defined plications, smooth median fold and sinus. Hamilton group. Alpena, Michigan. Cyrtina lachrymosa, sp. nov. PLATE XXVni, FIGS. 86, 87, 47. Shells small ; cardinal area high, more or less incurved. Surface with low and rather narrow median fold and sinus, on each side of which are two or three low, faint plications. Lateral margins of the cardinal area broadly rounded. BRACHIOPODA. 363 Surface covered with elongate pustules, some of them coarse, but the greater number quite fine. Height of an average specimen, 5 mm. ; width and length, 6 mm. Waverly group. Richfield, Ohio. Stringothtris Missouri, sp. nov. PLATE XXXIX, FIGS. 29-31. Shell small, cyrtiniform ; cardinal area high, slightly incurved toward the apex ; lateral cardinal margin broadly rounded, rendering the definition of the area quite obscure. Median fold and sinus neither wide nor highly developed. Surface of both smooth. Each lateral slope with five or six low plications. Interiorly the pedicle-valve bears strong divergent dental lamellae which are attached to the surface of the valve for fully one-third of its length. There is no median septum. The transverse delthyrial plate is thin and is developed into a delicate but distinct tube. Shell substance highly punctate on the inner laminae. Height of original specimen, 13 mm. ; cardinal width, 18 mm. ; length, 15 mm. Choteau limestone. Chateau Springs, Missouri. Ambocoelia 8PIN0SA, sp. nov. PLATE XXXIX, FIGS. 16-18. Shell of rather large size, hinge-line straight, equaling the full diameter of the valve. Brachial valve depressed convex in the umbonal region, concave ante- riorly, with upturned margins. Medially there is a low and indistinct elevation which disappears toward the front. Pedicle-valve not known. Surface bearing faint traces of concentric lines and covered with numerous elongate depressions which were probably bases of insertion of epidermal spinules. Length of original specimen, 7 mm. ; width in the hinge, 9 mm. Hamilton shales. Livonia Salt Shaft, Livingston county, N. Y. 364 PALEONTOLOGY OF NEW YORK. Semincla Rooersi, sp. nov. PLATE XLVU, FIGS. 1-i. Shell rather small, suboval in outline. Valves subequally convex. Pedicle- valve with a low, broad median sinus and brachial valve with a corresponding fold, both becoming more distinct toward the anterior margin. Lateral slopes depressed-convex. Umbones not conspicuous ; deltidium concealed. External surface smooth. A normal individual measures 15 mm. in length, and 13 mm. in greatest width. Pendleton sandstone (Schoharie grit). Pendleton, Indiana. Athtris densa, sp. nov. PLATE Xr-VI, FIGS. 6-li. Shell transversely elongate, valves compressed ; median fold and sinus not conspicuously developed. Pedicle-valve shallow, with broad, sharply angled cardinal slopes, greatly thickened interiorly. The anterior margin is frequently extended into a linguate process at the termination of the median sinus. Brachial valve the more convex, with an indistinct, flattened, and sometimes broadly grooved median fold with regular and even lateral slopes. In the interior of the valves the form of the muscular scars is normal, though there is a notable variation in the size of the diductor scars. St. Louis group. Washington county, Indiana ; Colesburgh, Kentucky. Seminula Dawsoni, sp. nov. PLATE XL VII, FIGS. 32-Sl. (See pages 95, 96.) This species was originally identified as Aihyris subtilita. Hall, by Davidson (Quarterly Journal of the Geological Society of London, vol. xix, 1863). Its diflferences from this species are indicated on the pages referred to. Carboniferous limestone. Windsor, Nova Scotia. BRACHIOPODA. 365 Meristella Walcotti, sp. nov. PLATES XLUI, FIGS. 16. 17 ; XLIV, FIGS 6-11, 23, 32. Shell elongate-ovate, valves convex, regular. Pedicle-valve with umbo moderately full and beak incurved ; foramen generally concealed at maturity. Cardinal slopes concave and well delimited by divergent cardinal ridges. Dor- sum more or less distinctly ridged in the umbonal region, broadly convex ante- riorly and slightly extended on the anterior margin, but with no median sinus. Brachial valve with the median elevation somewhat more strongly defined, especially in the umbonal region. Umbo-lateral slopes rather more abrupt than in the other valve. Internal structure normal for the genus. Oriskany sandstone. Cayuga, Ontario. Merista Tennesseensis, sp. nov. PLATE XLII, FIGS. 1-6. Shell subpentahedral in outline, transverse, rarely elongate. Valves sub- equally convex, with broad, low fold and sinus developed on the anterior por- tion of the brachial and pedicle-valves respectively. Umbo of pedicle-valve not conspicuous, apex truncated at maturity by a circular foramen. Deltidial plates concealed by incurvature. Umbo of brachial valve full, apex acute. External surface smooth. Dimensions of an average example: length, 17 mm.; greatest width, 19 mm. Upper Silurian. Perry county, Tennessee. Zyoospira putilla, sp. nov. PLATE LIV, FIGS. 85-37. Shell small, elongate-suboval in outline. Pedicle-valve the more convex; umbo narrowed, apex acute, delthyrium unclosed. Medially this valve is ele- vated by a strong double plication, the parts of which diverge anteriorly, leaving a flat, low depression between them, and in this lies a single faint plication. The lateral slopes are considerably depressed, and each bears from four to 366 PALEONTOLOGY OF NEW YORK. seven coarse, often irregular plications, only a part of them reaching the beak. The brachial valve is depressed-convex, with a conspicuous median fold, grooved longitudinally and bounded by deep marginal depressions. The lateral slopes are more convex than on the other valve, but are similarly plicated. Surface of the valves usually without concentric growth lines. An average example has a length of 8 mm. and a greatest width of 7 mm. Hudson River group. Near Edgewood, Pike county, Missouri. Camarophoria rhomboidalis, sp. nov. PLATE LXU, FIGS. 2S-29. Shells of rather small size, subtriangular in outline with cardinal margins extending for half the length of the valves. Pedicle-valve with apex scarcely elevated, incurved, with deltidial plates usually concealed ; slightly convex about the umbo, broadly depressed medially, forming a sinus which makes a linguiform extension on the anterior margin. This sinus may bear one and sometimes traces of two other low plications. The lateral slopes are smooth, except at the margins, where there is faint evidence of one or two plications on each. The brachial valve is convex and broadly rounded with abrupt umbo- lateral slopes ; broad, low median fold, apparent only in the pallial region, and bearing a median plication. Traces of two lateral plications are visible at the margin of the valve, and these are somewhat more distinct on the surface than on the opposite valve. Surface smooth or with fine concentric lines. The in- terior structure of the shell is normal for this genus. Corniferous limestone. Cass county, Indiana. Parastrophia divergens, sp. nov. PLATE LXin, FIGS. 4-7. Shell of medium size with strongly convex brachial valve and depressed convex, anteriorly concave pedicle-valve. The beak of the pedicle-valve is erect, but not conspicuons ; from the gently convex umbo the surface slopes BRACHIOPODA. 367 gradually to the lateral margins, and abruptly to the front, forming a broad and deep sinus, which is sharply defined at the sides, and bears from two to four angular plications. Two or more smaller plications occur on each lateral slope. The brachial valve is well rounded in the umbonal region, but the median fold is defined only near the anterior margin. It bears from three to five pli- cations, with three on e:ich lateral slope. All the plications, as well as fold and sinus, become obsolete in the umbonal region, and in old and thickened shells the latter can be distinguished only at the anterior margins of the valves. In the interior there is a supported spondylium in the pedicle-valve, but in the brachial valve the septal plates do not unite. Hudson River group. Wilmington, Illinois. Parastrophia Greenii, sp. nov. PLATE LXIII, FIGS. 17-20, 22. Shell robust, with convex brachial valve and shallow pedicle-valve, convex in the umbonal region, but concave anteriorly. Beaks not prominent ; that of the pedicle-valve low but erect ; that of the brachial valve full and incurved. Cardinal slopes sharply defined on pedicle-valve. Median fold and sinus on brachial and pedicle-valves not stronglyjdefined except at the anterior margin. The brachial valve bears six broadly rounded plications which are obsolete in the umbonal region ; four of these belong to the median fold, the other two to the lateral slopes. The pedicle-valve has five plications, with three in the me- dian sinus. Interior with a median supporting septum in each valve. Niagara dolomites. Near Milwaukee, Wisconsin. Parastrophia multiplicata, sp. nov. PLATE LXin, FIGS. 16, 18, 21. This species differs from P. Greenii in its more conspicuously developed me- dian fold and sinus, flatter and larger plications, and the greater number of the latter on the lateral slopes. The usually sessile spondylium of the brachial valve may also prove a distinguishing feature. Niagara dolomites. Near Milwaukee, Wisconsin. 368 PALjEONTOLOGY OF NEW YORK. Parastrophia latiplicata, sp. nov. PLATE l.XIU FIGS. 2S-87. This species is distinguished from the two preceding by its smaller size, less robust form, two broad plications on the fold and one in the sinus, with but a single pair on the lateral slopes. Niagara dolomites. Near Milwaukee, Wisconsin. LlORHYNCHHS Lesleyi, sp. nov. PLATE LIX, FIGS. M-SS. Shell of medium size with shallow pedicle-, and deep brachial valve. Median sinus on the former well defined ; median fold on the latter broad and not sharply delimited. Surface of both valves sharply and abundantly plicated. Upper Devonian. Pennsylvania. Barrandella Areyi, sp. nov. PLATE LXXI, FIGS. 14-16. Shell small, ventricose, with sinus on the pedicle-valve and fold on the bra- chial valve. Surface on both valves rather sharply and coarsely plicated, the largest plication being in the median sinus, with traces of finer ones on the slopes of the sinus. The median fold bears two well-defined plications with faint traces of others, while on each lateral slope of the valves there are four or five less sharply angular ribs. Clinton group. Rochester, N. Y. CONCHIDIDM GreENII, sp. nOV. PLATE LXVI, FIGS. 20-22. Shell subequally biconvex, ventricose, subcircular in marginal outline. Um- bones full and rounded, both incurved, that of the pedicle-valve somewhat elevated. There is no evidence of median fold and sinus. Surface of each valve bearing, over the palli.al region, from forty-five to fifty rounded plications. BRACHIOPODA. 369 which very gradually increase by implantation and become more numerous anteriorly. These plications are of slightly unequal size, which appears to be due to variation in the rate of their multiplication. In the umbonal regions the plications are obsolete. Niagara dolomites. Near Milwaukee, Wisconsin. CONCHIDIUM CRABSIPLICA, sp. nOV. PLATE LXVI. FIGS. 24, 2S. Shell elongate, subelliptical in outline. Valves subequally convex, depressed above ; cardinal slopes broad and abrupt on both. Umbo of the pedicle-valve erect, not prominent ; surface slightly elevated medially. Umbo of brachial valve depressed, apex concealed ; median region depressed anteriorly ; surface of both valves bearing broad rounded plications, separated by deep grooves. Of these plications there are from eight to ten on each valve over the pallial region ; by dichotomizing these become more numerous anteriorly. Niagara group. Near Louisville, Kentucky. CoNCHiDiUM Geokgi.®, sp. nov. PLATE LXVr, FIGS. 18, 19. Pedicle-valve unknown ; brachial valve trilobed by the development of a strong median fold which extends from apex to margin, and is sharply delim- ited by abrupt lateral slopes. The sides of the valve are convex, rather narrow, and slope abruptly to the lateral margins. Umbo full and incurved. Surface covered with numerous duplicating plications, of which from fifteen to twenty may be counted on each side at the margins, and twelve to fourteen in the fold. Clinton group. Trenton, Georgia. Capellinia mira, sp. nov. PLATE T-XX, FIGS. 6-14. (See pages 248, 249.) 370 PALEONTOLOGY OF NEW YORK. Selenella qracilis, sp. nov. (See page 270, figs. 184-186.) Oriskania navicella, 8p. nov. PLATE LXXIX, FIGS. 25-27. (See pages 269, 270, figs. 181-183.) RensseljEria Cayuga, sp. nov. PLATE LXXV. FIGS. 1, 2. Shell lenticular, often of large size ; suboval in marginal outline. Valves subequally biconvex, sloping regularly in all directions. Apex of the pedicle- valve scarcely prominent ; umbo not conspicuous, somewhat elevated medially. Divergent cardinal ridges and cardinal slopes well defined. Brachial valve with apex depressed and concealed ; somewhat less convex in the umbonal region than the opposite valve. Surface of both valves covered with a great number of fine, simple, thread-like, rarely duplicating plications, of which from seventy to one hundred may be counted on each valve near the anterior margin. Oriskany sandstone. Cayuga, Ontario. Begcheria Davidsoni, nom. nov. PLATE LXXIX, FIGS. 33-36. (See page 300, fig. 224.) INDEX PALEONTOLOGY OF NEW YORK, VOLUME VIII, PARTS I AND II. I. Register of Authors' Names. (Theae references do not inelude names osed ia association with specific designations.) Abich, H., Agassiz, A., Agassiz, L., Aldrorandos, Allen, vr. F Ami, H. M Angelin, N. P., . Archiac, E. J. A. D. 4. 2o.->, 2«o, 273 286. 307, 310, 321 Billings, W. R., . . ... II, 148 Binney, W. G .1, 216 Biltner, A., . I, 298; II, 45, 87, 100, 102, 105, 122, 269, 272 BlainviUe, H. H. D. de, I, 246, 246, 247, 249, 250, 252 279; II, 178 Bolten . I, 2 Boochar.1 I, 301 Bronn, H. G , . . I, 2, 80, 186; II, 328 Brooks, W. K., I, 162 Bruguiire, J.O., . . I, 2, 321 Bucb, J... Ton, . 1,80,189,200.201,201,211,221, 233 .263, 267, 276, '290, 303, 321, 333; II, 11, 12, 40, 112, 113 187, 196, 202, 203, 214, 2-25, 241, 282, 293 TABS. Calvin, S., . I, 188, 206, 285; II, 4, 5, 18, 28, 32, 95 241,294, 297 Carpenter, W.H I, 149; II, 49 Castelnan, F. de, . . 1,187,200,250,276,281, 303 n, 1, 12, 14, 18, 28, 73, 103, 255 Chemnitz, J. H., I, 321 Clarke, J. M,, 1,3,121,146,189,206,209,254,27-2, 273 277, 290, 2S1, 304; II, 4, 5, 13, 18, 28, 59, 66, 69, 109 141, 161, 164, 185, 193, 196, 203, 219, 225, '265, 269, 307, 309 Claypole, E. W, . . . n, 54, 261 Clinton, G., n, 160 Conrad, T. A., . I, 2, 56, 69, 186, 187, 192, 196, 193, 200 201, 204, 205, 263, 257, 276, 280, 281, 284, 290, 295, 303 321, 3-28; II, 1, 12, 14, IS, 21, 28, 31, 51, 73, 80, 83, 134 136, 103, 182, 183, 187, 189, 204, 231, 241, 255, 302 Cotton, H I, 252 Co.\, E. T., . I, 3, 187, 211, 264 Cozzcns, I n, 80 Crane, A., H, 297 Cuvior, G. C. F. D I, 122, 143, 160 Da Costa, E. M., I, 321 Dall, W. II., I, 2, 14, 33, 34, 36, 44, 45, 83, 118, 120, 121 122, 123, 128, 138, 145, 150, 151, 155, 160, 236, 277 II, 138, 193, 235, 305 Dalman, J. W., . I, 186, 191, 192, 204, 203, 233, 236, -276, 277 280, 290, 295, 296, -297, 303, 321; II, 9, 40, 41, 58, 61 65, 67, 163, 185, 195, 231, 241 Dana, J. D. ■ . I, 2 Darwin, C. II, 137 Davidson, T., . . 1,8,9,10,14,15,16,17,18,19, 20 21, 22, 27, 31, 33, 34, 35, 36, 39, 40, 41, 43, 44, 45, 46, 48 51, 55, 50,-57, 58, 62, 63, C5, 66, 78, 79, 80, 83, 84, 85, 67 90, 91, 91, 98, 100, 101, 103, 107, 108, 110, 111, 112, 113 115, 120, 12-2, 1-25, 126, 127, 1-28, 1-29, 133, 13S, 141, 142 147, 148, 149, 150, 151, 152, 155, 156, 158, 160, 191, 192 193, 200, 201, 302, 20.!, 204, 205, 211, 212, 214, 227, 233 -241, 212, 243, 245, 2I«, 249, 250, 253, 254, 257, 259, 261 264, 267, 268, 269, 270, 271, 271, -279, 280, 281, 284, 285 286, 290, 295, 296, 297, 298, 300, 301, 303, 304, 306, 313 314, 817, 319, 320, 321, 833, 331, 335; II, 2,7,8,9, 10 17, 20, 21, 22, 30, 33, 40, 41, 43, 50, 51, 53, 58, CO, 62 63, 63, 06, 67, 68, 70, 71, 73, 76, S3, 87, 83, 91, 92, 93 95,97,98,101,103,112,113, 114, 115,1-22, 129, 131, 134 144, 149, 153, 153, 1.56, 158, 139, 161, 163, 164, 168, 172 174, 178, 185, 187, 195, 196, 198, 200, 203, 204, 208, 210 21, 215, 21C, 217, '219, 2-21, 2-25, 227, 231, 236, 237, 240 241, 242, 243, -249, 250, 2.55, 265, 272, 274, '277, 2J.1, 282 286, 288, 289, 293, '294, '295, 299, 300, 302, 305, 307, 311 322, .-jas 372 INDEX. PAOE. ,J.W., . I. 70, 107, 120, S8S,8M, S22; II, 4, 14, 61 84,219,291, 293 D«oh«ii, II. Ton II, 24 Oalhuice, I. MS, 246, 247, 249, 250, 252; II, 113, 282 Darbr, O. A., . I, 120, 145, 188, 208, 211, 213, 214, 216, 254 261,287,268, S04, 314, S22; II, 3, 4,22.51, 84,98, 120 121, 122, 138, 140. 265, 206, 267, 272. 274, 28B, 292, 293 302 Oulongchampg, E., . . II, 320 Dewey. C, II, 128 DiUmar, U, 311, 312 Dumcril, A I, 2, 145 Dwighl, W. B., I. 116, 126. 138 Dyer. C. B I, 138, 272 Eaton. A. 11,83, 255 Kiohwald, E. TOn. .1,80,110,152,200,201,231,233, 245 2G6, 269, 276, 297, 298, 321, 337; II, 225, -.>27, 2%, 241 Emerson, B.K I, 8, 304; II, 231, 273 Emmona, E.. . 1,2,3,56,138,145,186,195,200,201, 205 215, 257, 269, 281, 2S5; II, 2, 12, 116, 231 Endlicber I, 104 ElheriUge, K., Jr., 1, 335, 336; II, 4, 51, 65, 164, 231, 242 Erans I, 256 Fahrenkohl, A., I, 303 Fischer de Waldlieim. . I, 249, 253, 256, 303, 317, 321; II, 8 178,244, 245 Fischer, P., . . • . . II, 182, 187 Foerste, A. F., . I, 188, 189, 193, 198, 201, 206, 209 228, 254, 291, 295; II, 5, 13. 63, 164, 236, 240 Ford, 8. W., 1,51,56,66,67,68.69,70,71,72,75,76,77, 78 Freeh, F., 1, 62 Fricle n, 305 Gagel. C, . . . 11,223,225,231,236, 250 Gamier, F. I, 268 Geiniti, U. B.. . 150, 214, 217, 261, 287, 304, 314. 319; II. 3 22, 51, 84, 120, 210, 215, 293 Glass, N.. . . 11,9,62.67.71,87.92.97.98,101,131, 159 274 Goldftus, A. 1,303,321, 333 Gosselct, J.. II, 189 Gould, A. A. 1. 123 GraUolet, P I. 65 Gray, J. E I. 122; U, 340 Greene, T. A U, 199, 222, 249 Grucncwaldt, . . . . . . II, 231 GoUUer, A., . . , . . . I, 65 Gurlcy, W. I, 145; 11, 174 llall, J., . . 1,2.3,14,18,33,36.40.44,46,66,59, 61 66, 67, 69, 73, 87, 91, 120, 122, 138, 142, 145, 155, 187, 188 192, 194, 195, 19ton, •■.... II, 2 PAOE. Ilaupt 1, 291 Hayden, F. V., . I, 8, 66, 120, 281, S64, 303, 301, 322 II, 2. 3, 61, 54, 80, 83, 120, 151, 293 Helmerscn, G. von I, 319, 320 Herrick, C. L., . I, 3, 9, 121, 138, 189, 209, 254, 2«1, 304 323, 328; II, 4, 5, 23, 43, 47, 50, 52, W, 109, 109, 189 192,265, 286 Herzer.H II, 97 Hicks, H I. 6 Hinde, G.J 1, 188, 201; II, 58 llisinger, W. von, . I, 200, 201. 276. 200. 303; U. 10. 163 185, 231 HoU. H. B I, 6. 90 Hocmcs, . . . . . . . II. 281 Uolzapfcl.E, II, 131 Uowse II. 211 Hosted. J. W., n, 120 Haxley, T. H I, 1, 186 Hyatt, A. • . . . n. 65 Ives. J. C, I, 286 Jaekel. O I, 291 James, J. F. I, 8 James, U. P.. . I, 3. 18. 19. 116. 188. 201. 206. 215, 276, 281 295; II, 151 Joubin, E. I, 1, 147, 119 Kayser, £., I. 153. 211, 211, 242, 263, 259, 260, 2!-5, 286, 290 II, 33, 40 101, 112. 172, 175, 195, 196, 197. 216, 211 217, 200, 281 , 282, 313. 313, 316 Keyes, C. K I, 301. 823; II. 1. 81 Keyscrling. A. von, .... I. 307, 317 Kiesow. . . . . . . . II, 250 King, C I, 01; II, 228 King, W.. . I. 2. 7. 10, 11, 13, 11. 18. 20, 21, 22, 30. SI, 33 31. 35, 36, 38. 40. 41, 43, 44, 45, 46, 48, 61, 5i, 55, 67, 62 63, 145, 147, 1«9, 156, 186, 200. 201. 201. 211, 245. 248 219. 251. 252, 267, 276, 3U, 317, 319, 320, 828, 339 II, 8, 47, 49, 50, "1, 87, S9, 91, 103, 195, 210, 214, 225 227, 283, 285, 293, 2!«. 322. 339 Klooden, K. F. von I, 276, 303 Kccnig, . . . . . . . II, 8 Koninck, L. de, . 1,211,253,267,376,301,302,303,306, 314 317, 319, 321, 323, 325 333, 334; II. 9. 98. 119, 122 202, 203, 208, 266, 294, 296. 299. 314. 315 Kowalevski II. 828. 330 Krotow • I. 310 Kntorga. S., . I. 80. 82. 85. 101. 102, 103, 109, 110. 111. 112 113, 115, 116. 120. 128. 136, 136, 158, 160; II. 31 I.acaze-Dnthler8, . . I. 16 Lalmsen 1, 230 Lamarck, J. P. B. A. dc M. de, I, 6, 120, 121, 122. 115, 321 Laubc II, 103 Linck I, 821 LindstrAm. G.. . I, 33, 31, 36, 38. 201. 201, 241. 245, 271 II, 82, 67, 161, I80, 219, 231, 231, 211, 307, 322 LInnarsson, J. G. O., I, 86, 91, 91, 97, 98, 99, 101, 107. 108 Linnc. C. . . . I, 115, 150, 204, 213; II, 163, 231, 231 Marcou. J., . I. 187. 208, 322; II, 2, 21, 22, 83, 120, 202 Marcy, O.. I. 281; II, 241 Martin, W., 1, 211, 321; U, 33, 17, 202, 214, 216, 293 Mather, W II, 1, 12, 21. 201 Matthew, G. F., - I, 66, 58, 69, 81, 91, 93, 99, 101, 102, 103 105, 107, 137, 183, 231, 282, 233; II, 326 Hanrer, F., I, 269 INDEX. 373 PAGE. McChesney, J. H.. .1,120,187,188,194,196,261,262, 322 350; 11, 2, 3, 12, 13, 18, 2*. 51, 58, 83, 84, 1^0, 1G3 164, 20j, 236, 238, 277, 281, 293 McCoy, P., . . 1,85,85,129,153,158,187,200,201, 203 204,211,233,245,253,261,263,276,280,284,290, 298 303; II, 9, 21, 33, 33, 47, 62, 83, 81, 87, 89, 92 93, 134, 185, 195, 214, 249, 282, 293 Meek, F. B., I, S, 33, 36, 56, 62, 64, 66, 90, 97, 101, 103, 120 127, 132, 135, 187, 188, 194, 196, 198, 201, 205, 208, 211 214, 215, 217, 245, 259, 2J3, 254, 261, 267, 269, 272, 276 281, 284, 290, 295, 303, 304, 30D, 322, 328; II, 2, 3, 4 8, 15, 18, 22, 23, 28, S3, 43, 47, 49 50, 31, 5t, 58, 73 80, 83, 84, 120, 136, Ijt, IGl, 161, 182, 193, 203, 204 215, 241, 249, 251, 252, 254, 261, 264, 277, 293, 302 311, 312 Michaad, A. L. G I, 321 MickwiU, A I, 337, 339 Miller, S. A, I, 3, 8, 133, 119, 188, 1»4, 196, 198, 201 202, 205, 208, 245, 272, 276, 281, 295, 323; II, 4, 23, 26 28, 154, 182, 185 Mailer, V. tod I, 95, 96, 102 Morris, J., . I, 110, 135, 303; II, 136, 137 Morse, E S., 1, 8, !6 Morton, S. G., .... I, 321; II, 21, 10, 293 MttUor, O. F I 122, 145, 150 UUnstcr, G. von, I, 314 Manicr Chalmas, I, 28, 298 Murchison, U. I., I, S«, 227, 328; U, 24, 138 Nettelrolh, U., . I, 3, 146, 189, 1A3, 188, 201, 206, 209, 211 251, 277, 288, 290, 301, 328; II, 5, 13, 15, 18, 23, 28, 40 43,54,59,66.73,80,81,109,124, 142,154,164,181, 182 185, 219, 231, 234, 235, 236, 242, 250, 265, 286, 2»i, 302 Xeumajr, M. I, 301, 324 Newberry, J. 3., . . I, 9, 204, 266, 303, S22; II, 2, 22, 83 Mieholson, II. A., I, 3, 33, 36, 120, 138, US, 188, 1>2 201, 254, 285, 804, 32S; II, 3, 15, 43, 58, 73, 193 Noctling, K II, 225, 226, 227, 229 Norwood, J. G , . I, 303, 312, 321, 328, 332, 333; II, 2, 21, 51 NoT»k,0., 11,231, 235 CEhlert, I>, r., . 1,28,153,208,209,210,233,241,243, 250 251, 261 , 287, 269, 272, 277, 286, 287, 288, 289, 295, 802 310,328,333,335; 11,54,55,50,103,104,115,182, 187 IM, 196, 197, 198, 210, 215, 230, 241, 242, 2«, 245, 252 254, 258, 283, 264, 285, 266, 272, 273, 277, 281, 305, 323 OMham, B I, 29 Orbigny, A. A', . I, 120, 128, 136, 138, 141, 158, 160, 186, 214 217, 2.13, 2:14, 237, 245, 303, 321 ; 11, 1, 16, 51, 83, 88 112,163,225,227,281, 307 Owen, D. D., I, 2, 5B, 187, 192, 200, 208, 225, 245, 261 284, 303, 321 ; II, 1, 2, 21, 28, 163, 211 Owen, B., I, 2, 16, 186 Tander, C. H., . I, 80, 117, 118, 119, 141, 180, 192, 200, 221 233, 2S4, 336, 236, 237, 238, 250, 284, 295, 296, 297, 298 II, 225, 227 rarkinson, J., . . I, 821 rhillips,J., I, 2, 6,13,201,211,245,253, 256,257, 261 260,278,281,303; II, 11, 40, 62, 89, 92, 93, 185, 19S 200, 202, 204, 214, 216, 217, 2115, 282, 294 Pilabry, H. A I, 246 I'oli, J. X I, 145, 147 Potiez, V. L. v., I, 321 I'oalson, C. A., . . . . I, 250 Pratten,II., I, 303,312,821, 328,SS2,33S;n,2,21,61,I01, 112 Front, H. A I, 321 Quenstedt, F. A., I, 80, 109, 110, 200, 205, 211, 219 241, 245, 267, 301 ; II, 31, 34, 40, 58, 73, 88, 101, 102 113, 114, 174, 175, 178, 195, 196, 203, 231, 241, 245, 260 277, 281, 282, 283, 281, 285, 293 Bafluesqae, C. S., . I, 245, 246, 247, 248, 249, 250, 252 Ramsay, A. C, I, 204 Bang, A. S I, 821 Uatbban, K., .1, 3, 120, 188, 304, 328; XL, 3, 4, 18, 43, 138 262,254, 303 Beeve, L. A., I, 121 Retzias, A. J I, 145, 150 Richthofen 11, 315 Rieman, P. I, 218 Rigaux, E I, 241 Ringucberg, E. N. S., . I, 3 120, 146, 189, 204, 205; II, 4, 13 Rffimer, A II, 40, 231, 241 Roimer, F., . I, 2, 187, 205, 276, 290, 302; U, 1, 2, 16, 21 31, 65, 163, 195, 211, 245, 255, 277, 282 I, 195, 201, 281, 284, 322; II, 2, 15, 22, 28 58, 73, 83, 97, 103, 255 II, 1.53, 266, 268, 272, 288 . 1,36,241; II, 54, I, 6, 36, 55, 56, 67, 53, S3, 81, 86, 107, 158, 187, 192, 196, 201, 204, 241, 246, 269, 274, 284, n, 62, 83, 136, 137, 138, 161, 163, 185, 195, 219, Rogers, H. D., Romiuger, C, Rouault, M., Salter, J. W., Sandberger, G. and F., 66 153 322 249 307 I, 253. II, 40, 112, 113, 129 130, 133, 195, 282, 302 II, 150 I, 188,199,200,241, . I, 145, 341 150 Saixlcson, F. W. Safford, J. M., Schauroth, K. F. .Schenck II, 141 Schiel, I, 321; II, 83 Schlotheim, E. Ton, . I, 145, 155, 158, 180, 200, 202, 211 213, 233, 253, 267; II, 113, 103, 225, 227, 293 Schnur, S., . I, 241, 253, 257, 259, 284, 30!; II, 31, 40 112, 129, 130, 131, 172, 195, 282, 302 Schmidt, Fr. . I, 288, 290; II, 1G2, 195, 236, 241 Scbuchert, C, . I, 26, 88, 112; II, 8, 47, 50, 51, 67, 150, 151 151, 157, 294. 297, 346 .Schumacher, I, 121, 122, 123 Secbach, K. von, . . . . . I, 101 Semcnow, P., . . .1, 263, 293; II, 311, 312 Shalcr, N. S., . . I, 187, 189, 192, 196, 198, 208, 233, 216 276, 281, 288, 293; II, 3, 83, 164, 219 Sharpe, D., . I, 118, 138, 141, 248, 303, II, 1, 136, 137 225. 227 Shipley n, 330 Shepard, C. U I, 321 Shumard, U. F., . I, 8, 120, 145, 187,803, 31», 321, 322 II, 1,2, 21,28, 43, 47,31,83, 163, 193, 202,214, 215, 293 Simpson, G. B., 1, 189, 209, 304; II, 43, 47, 50, 73 Sowerby, J., . 1, 120, 121, 122, 150, 155, 158, 192, 203 204, 211, 227, 245, 253, 276, 284, 290, 317, 321, 328 U, 1, 7, 8, 24, 47, 134, 163, 178, 185, 195, 199, 202, 231 236, 237, 282, 293 Sowerby, J de C, . I, 121, 276; II, 62, 195, 202, 219, 236 237,241, 219 Spencer, J. W., . . . . . . I, 146 St. John, C, . .1, 145, 264, 314; II, 293, 300, 301, 302 .Steiningcr, , . . . . . II, 101 Steinmann, G., * . . . , . II, 141 374 INDEX. I-AOE, I, 803 I, 145 I, 29 n, 141 II, 70,n0S. 1». ISS. 178, Sn, «78, 279, 283. 285 n, 138 . I, 187, SOS. 2M, 284,332, 3-28; II, 2, 3, 18 Sa, 43, 47, SO, 83, 119, 1'20, 215, 203, 293 I, 218 II, 3, 84, 293 Tschenij-schaw, Th., . I, MI, 243; II, 26, 84, 78, 172, 175 176, 210 Trautaohold, H. von I, 214 Troost, n, 47 Stobam.K., Stollczka, F., Stabel, Sums, E., . Swmtnaon, Swallow, G. C, Swinton, F. S., Tottla, F., . Tryon, G. W., Ulrich, A., Ulrich, E. O., I, 246 . n. 136,138, 141, 302 1,24,25,27,32,63,87,88,89,112, 120 138, 148, 188, 194, 295; II, 154, 193, 231 Ure, D. I, 303, 321 Vanuxoni, L., . I, 2, 120, 186, 205, 211, 263, 257, 258, 276 281, 281, 290, 303, 328; II, 1, 12, 14, 17, 21, 53, 73, 163 191,195,204,232, 25j Verncail, E. de, . I, 110, 111, 141, 151, 191, 200, 201, 204, 214 219, 233, 233, 215, 253, 256, 2Ct, 2C6, 269, 276, 280, 283 297, 298, 300, 301, 303, 317, 319, S21, 3.>3, 326, 328, 333 11, 1, 11, 21, 67, 101, 103, 104, 112, 131, 138, ICl, 172 178, lifi, 202, •no, 214, 226, 227, 223, 231, 236, 241, 242 249, 277, 278, 279, 282, 293, 302 Verchfire II, 98 Verwom, ....... I, 166 Volborth, A. von I, 73, 82, 83 Waagcn, W., 1,28,29,30,84,89,90,94,95,118, 117 154, 210, 214, 215, 216, 217, 239, 254, 256, 261, 262, 263 264, 265, 267, 2ljS, .301, 306, 307, 308, 310, 313, 316, 317 319, 320, 324, 325, 326, 330, 331, 332; II, 9, 21, 26 34 91, 98, 99, 116, 119, 121, 122, 123, 1(.7, 182, 196, 197 208, 209,!215, 260, 205, 267, 272, 274, 2!I3, 2»«, 295, 296 298, 299, 300, 301, 802, 313, 311, 315, 310, 319, 322, 823 326, 83<,33(>, 310, 343 Wahlenberg, II, 40, 103, 195 Waller . I, 146 Warth, H I, SO Walch.J. E. J 1. 821 Walcolt, C. v., . I, 8, 9, 66, 67, 58, 66, 67, 08, 69, 70, 71, 72 76, 78, 91, 92, »;, 98, 99, 100, 101, 102, 103, 101, 105, 106 107, 111, 113, 114, 110, 117, 121, 137. 146, 166, 188, 1S9 193, 194, 198, 206, 211, 230, 231, 232, 211, 243, 210, 264 269,278,285,290,801,311,828,331; 11,4,15,18, 23 28, 33, 43, 47, 50, 62, 73, 84, 120, 124,'a27, 142, 164, 189 193, 200, 20.3, 219, 221, 212, 286, 291, 321 Waklheim, G.F. de, . I, 191,214,215,264, 266, 275; II, 203 Wcndt, A. F II, 275 Wenjukoir, P I, 269 White, C. A., 1,3,90,98,101,120,121,146,1)6, 187 188, I9J, 190, 198, 2*1, 206, 208, 209, 211, 215, 263, 264 277, 281, 285, 304, 814, 322, 323; II, 2, 3, 13, 14, 18, 22 28,28,43,47,61, 62,64, 83, 112, 119, 120, 142. lot, 263 210,216,249,250, 293 Whiteaves, J. F., . I, 8, 27, 40, 44. 43, 40, 06, 113 115, 244, 293, 814; II, 6, 18, 16, 23, 108, 200, 231, 242 261, 264, 282, 285, 810 Whitfleld, K. P., . I, 3, 11, 36, 48, 57, 59, 61, 02, 6« 69, 120, 187. 188, 189, 196, 193, 200, 208, 209, 211, 218, 230 233, 239, 240, 245, 240, 253, 254, 269, 277, 281, 285, 304 310, 311, 822, 323; II, 2, 3. 4, 13, i:>, 18,22,28, 40, 61 69, 65, 77, 84, 89, 112, 113, 142, 164, 174, 175, 193, 195 212, 213, 214, 215, 225, 231, 236, 239, 240, 241, 242, 249 260,275,276,286, 293 Wilctens, C. F I, 270, 279 Williams, II. S., . I, 3; II, 4, 6, 33, 196, 203, 271, 317 WinchcU, A., . I, 8, 62, 64, 120, 145, 152, 167, 188, 208 211, 253, 284, sot, 814, 823, 328; II, 2, 3, 8, 16, 22, 47 60, ,'■.1,73, 83, 108, 1>4,1S<),193,212,241, 266,267,271, 286 Winchell, N. H., . 1,8,69,62,116,088,194, 195 206, 281 ; II, ISO, 161, 164, 167 Woodward, .S. P 1, 6« Wiiolson U, 188 Worthcn, A. II., I, 8, 86, 62, 64, 120, 121, 188, 268 261, 270, 281, 290, 303, 309, 322, 328; II, 2, 5, 16, 18, 22 23, 28, 33, 43, 47, 73, 83, 84, 136, 161, 164, 204, 215, 241 249,251,252,254,302,311, 812 Wynne, . . .... I, 29 YandoU, I.,. P I, 187; II, 1, 28, 47, 188 Vouug, J., . I. 307; II, 10, 20, 30, 93, 307, 809 Zittel, K. A. Ton, I, 124, 272, 295, 808; II, 115, 178 Zugmayer, U., I, 298; II, 46, 73, 87, 96, 313, 314 II. Register of Genera. Acambona, Acriti; Acrothole, AavthtUr, . Acrotreta, (Namea in italict are synonyms; figures in fdll-pace type denote place of description.) Jerotreta, . Actinoconcbos, Ambocoilia, Amphiclina, Ampbigenia, PAGE, . II, 105, 118, 119 I, 80, 82 I, 70, 08, 99, 100, 102, 103, 108, 1 13, 114 167, 168; II, 324 I, lOI I, 68, 93, 66, 96, 99, 100, 101, 1U3, 104, 105 106, 108,109, 113, 114, 100, 167, 168; II, 321 I, 96, 105 II, 92 I, 92; II, 3, 84, 55, 56 I, 302; II, 103, 315 II, 233, 261, 268, 253, 257, 200, 261,262, 263 264,341,842, 849 Amphiatropbia, Anabaia . Anastropliia, Anaxyga, . Ancistrocrania, Anlsactinclla, AnomactincUa, Anomia, Anomites, Anoplia, . Anoplotheca, Antirhynchoiulla, I, aoa 11, SI 9, 223, 225, 227, 228, 233, 239, U. . I, 146, 211, 321; II, 40, 47, . I, 233,276,321; II, I, 220, 302; II, lao, 133, 134, 142, . n, 231, 242, PAGE. ; II, 339 II, 141 249, .311 154, 156 I, 149 n, 108 U, 103 168, 315 163, lO-i 1, 30» 137, 189 144, 846 244, 246 INDEX. 375 PAGE. PAGE. AritanUittt, I. 321 Christianla, I, 298 Area, I. 821 CistcUa, . . 11,305,828, 330 Argiope^ II, 328 Clavagelta, 1,321. 333 Athyris, . H, 11, 83. 83, 86, 88, 89, 91, 92, 93, 94, 97, 98, 100 Clintonella, II, 169 118, 121 Ut, 291,317, 334, 313 Cliothyris, 11,89, 91 Atkyris, U, 2, 3. 63, 65, 73, 73, 85. 93, 121, 154, 328 Clitambonites, 218. 219. 230. 231. 232, 333, 231, 236, 237 Atrypa, . I, 207, 298; II, 89, 131, 163, 171, 173, 174 239, 240, 243, 340; 11, 327, 328, 332, 333, 336, 341 175, 176 Clorinda, U, 241 Atrypa, I, 187, 200, 269; II, 58, 62, 65, 73, 78, 80 Coelospiia, n, 134, 136, 137, 140, 144, 160, 339, 345 83, 87, 101, 108, 124, 127, 136, 142, 152, 154, 161, 180 Cartospiray 11,161, 162 185,189 , 193, 195, 202, 204, 214, 219 241, 249, 255, 293 Concliidium, U, 216, 230, a31, 234, 235, 236, 240, 261 307, 3-28, 338 334,336. 341 Atrypina, . . ,U, 153,161,171, 171 Conrhites, . I, 276 Aulacorhynchus, II, 72, 311, 312, 335 ConchyliolitkuSt . 11,47,202,214, 293 Aalonotreta, I, 8a, 337 Couoceplialites, I, 30 Auionotreia, I. 80 {Conradia,) I, 39 Anlosteges. . I, S16, 319, 330; U, 329, 340 Cranajna, 11,297, 301 Avlosteges, . I, 314 Crania, I , 1, 108, 122, 144, 145, 147, 149, 160, 151, 152 Avicula, I, 66 153, 164, 155, 156, 167, 168, 169, 170; II, 325 Bactrynium^ II, 813 Crmia, 1,110, 314 Barrandella, . II, 841, 24a, 247, 839 Crania {Pseudocrania) . . . . , I, 253 Barroisclla, . I, 1, 14, 6a, 64, 85, 108, 164; II, 322 CranicUa, 1, 153, 170; II, 325 326, 827 CraniotitM, I, 146 Beactaia, . n, »6o. 265 Craniops, . 1,165, 169 Becchcria, II, 300 Craniscus, I. 146 Bifida, II, 98, ISl, 133, 144 Criopoderjnn, . . . . . I, 146 Billingsclla, I, 829, tSl, 232; II, 212, 230, 333, 337 Criopus, 1,146, 147 BUliitgsia I, 75, 76 Cryptacanthia, n, 300, 302 Bilobites, . . I, ao*, 219,223, 229 C'ryptonella, 11, ase, 287, 288, 290, 291, 292, 295, 296, 297 Bouchanlia, II, 305 CryptotuUa, U, 265, 293, 334, 346, 347, 313, 349 Brachyprion, . I, 220, ass, 289, 282; 11, 339 Cyclorliiiia, II, aoo. 208 Brtuhymeruit n, 219 Cyclospira, . 11,63,146,151,152,344, 346 Brarhythyris, n. 10 CyctothyriSy II, 177 Branconia, n. 123 Cyrtia, n, 9, 11, 80, 32, 40, 41, 42, 46, 328, 331 Cadomella, I, 298 Cyrtia, 11,43, 47 Camarella, I, 234; II, ai9, 220, 221, 225, 233, 311 C>Ttina, . U, 16, 32, 41, 43, 46, 46, 50, 52, 63, 828 Camaretla, I, 269; II, 212 331, 342, 346 Camarium, II, 70, 72 Cyrtina, II, 28 Camaroplioria n, 72, 202, ai*, 216, 218, 227, 333, 334, 341 Cyrlothcca, n. 46 II, 199 Dalmanella, . I, a05, 218, 219, 220, 223, 229 Caraarophorella, 11, 218 Datidsoneilay 1, 28 Camarospira, 11, sa, 217, 342 Davidsoni^, I, 279, 301, 302 ; II, 339 Camarot<£cliia, II, 181, 1S9, 191, 192, 194, 198, 199, 201 Uavifsiella, I. 317 216. 220, 337, 342 Uayia, II, 63, 149 Capellinia II, 848, 841 Dcltliyris, . II, 9, 19, 20, 36 Caprotina, II, 816 Deltkyrii, . I, 186, 187, 200, 201, 20t ; U, 1, 2, 12, 14, 15 Cardinocrania, I, 30, 147, 134 18, 21, 22, 28 Catazyga, 11, 143, 157, 188, 159, 173 Derbya, . I, 219, 259, 258, 261, 262, 263, 205, 268, 347 Centronclla, II, 2S8, 280, a65, 2fi«, 267, 20S, 269, 270 II, 11, 336, 337, 338, 339 271, 272, 274, 276, 289, 291, 298, 347, 849 Derbyia, I, 261 Centrtmella, 11, 286 Dicamara, . U, 73, 335 CliarioDclla, II, 78 Dicellomus, . 1, 66, 68, 72, 73 Ckariimelta, II, 58. 73 Dicalosia, . I, 204 ClionctcUa, I, 307, 313 Dicraniscus, I, 270 Chonetes, . I, 191, 230, 280, 301, 303. 305. 306. 307. 308, 308 Dicraniscui, I. 269 810, 31 , 312, 313, 316, 320; 11, 11, 313, 337, 339, 340 Dictyonella, U, 307, 311 Ckmtt$,, . I, «U, 317; U, 311 Dielaiiina, . II, 275, 287, 293, 291, 296, 297, 298 301, 346 Clionetina, 1,307. 310 347, 348, 349 Chtmiopora^ I, 14% ISO Diclasmina, U, 298 Chonostrophla, . 1,307,310, 811 Dignomia, I, 2, 14, 15, 21, 163, 164 ; II, 322 Chonotrcta, I, 96, .104 107, 168 Diiiobolus, I, 23, 28, 30. 31. 34. 36, 39, 46, 47, 48, 50, 61 Chonopectos, 1,307, 3ia 5 i, 53, 64, 56, 81, 84, 139, 142, 165, 176 ; II, 322 Ckorutiut, . I, 414, 216, 264; U, 8, 2J, 37 DinoMus, . 1.38, 41 376 INDEX. Dinorthis, . UipliMpirelU, Diacina, Dutimt, I, Dtaelnlaca, {DiteimeearU .0, DtecInolepU Disciuup^U, DouriUina, Estonia, . Kicbwsldia, Elkania, . Kntclctcs, . Epiilifru, . Klhcridsina, Eunictria, . I, 7»,87 51,88. M. II, lot, 107. EunutriOt , Eunella, Kuractinclla, Etkyrii, Kiuella, Qtinitziat . Ulassia, Glassina, . Glos:»ina, . Glottidia, . Gonambonites, Gonambonit€»t GotlanJia, . Gmcncwaldtia, Oryphita, . Gypidia, Gypidala, . Ilalliiia, llarttina, . Ilebcrtclla, llelmersenia, Hel vtintholithus, Ilemipronites, HemiproniteSt llcmiptychina, HemithyriSf Ilctcrortbla, Illndella, . Ifipparionyx, HipparioHyXf Ilipparltes, Homoioapira, Hiutodia, . IlyatteUa, . Hj-poUijTU, Hfpotkj/rit, . Hytterolithes, Hytterolitkut, Ipbidea, Ipkidmit!), Zgogramma, iMorhymdiuM, Javavella, Karpin»kla, KayaeroUs, PAQE. I, 109. 22S, 227, 229 II, 103, S45 . I, laO, 121, 124, 149, 150, 160 SO, 96, 107, 1'^, 122, 114, 129, 132, 155 , liM>, 12S, 1S4, 125, 130, 131, 149, 169 I, 142 323 168 ass £05 335 326 I, 29, 90, 140, 111; U, I, 103, 109, 106, 167, I, 286, . II, 801, ao4, n, 7», 113, 30T, 312, 322, 323, , 6B, T9, 76, 77, 78, 105 ; II, 322, . I, ai*, 215, 216, 217, 228, . II, 77, 283, 1, 106, 116, 117, 118, 119, 120, 122, 206,315, II, II, aoo, II, . u, n. I, U, 148. 1»a, 153, 174, 344, . II, I, 2, 19, 16; II, . I, a, 14. IS, 63, 163, . I, 219, 236, I, n, 80, I. II, I, II, II, 233, 841, 212, 217, 248, 250, 336, 341, II, 150, 151, 155, 313, II, a»a, 1,198,222, . 1,117,118, II, I, 238, )S38, 239, . I, 233, 239, 215, 253, 254, II, aoo, . 1, 269; II, I, aoa, 223, . 11,63,65, . I, aST, 268, 283; 11,337, . II, II, . II, II, 105, 107, 109, 118, 119, l!i0, 122, . 11,61,61, . 11,195,201,202, II, 62, 177, 185, . 1,186,211, I, 186, I, 96, 9T, 166, 167, 168 ; II, 324, I, II, 311, II, 225, II, II, . I, ase, ; U, 346, 294 335 144 316 120 297 103 88 9 104 845 98 322 164 237 233 81 S3 175 321 231 342 314 317 229 119 231 250 261 300 62 229 81 338 163 316 Iia 128 160 203 219 213 213 327 90 312 227 272 170 346 Kaysoria, . Koyscrllngia, Ktitambonitet, KuiiinckcUa, Koniiickina, Kram^.-iina, Kutor^iua, Lacazolla, . Lakhmina, Lfiorhynehiu, Lephena, . Leptcrna, I Lepl(T.nalosia, LepUenisca, Lcpla'nulopsis, Ltptagonia, I.*plella, . Leptoboluft, Leptocoelia, I^ptoea-tia, . Leptodus^ Lcptostrophla, Ligulops, Lima, Lindstra'iuella, PAGE. II, 101, 102, 103 I, 117, 118, 119, 141 . I, 233, 235, 236 I, 298 3!« I, 301, 302 ; II, 103, 130, 839, 343, 345 II, 805 I, 90, 91,92, 98, 94, 95, 96, 97, 114, 140, 166 168, 183 ; II, 321 II, 328 I, as, SO, 35, 46, 47, 48, 62, 63, 89 ; II, 821 U, 193 I, 192, 220, 238, 250. 876, 279, 280, 282, 288 293, 296, 299 ; II, 213 47. 187, 196, 225, 253, 261, 2S1, 284, 811, 317 321, 328 ; II, 302, 337, 333 I, 314 I, 279, 300, 801 ; II, 839 I, »94 I. 276, 280 . I, a93, 294, 298 I, 73, 74, 75, 79, 165, 167 I, 320; II, 130. 137, 140, 142, 317 . II, 131, 161, 162 II, 313 . I, a88 ; U. 838 I. 19 I, 821 I, lao, 13*, 140 Lingula, . 1,1,2,5,6,8,10,11,14,15,16,18,21,22,23, 24 25, 27, 23, 32, 48, 49, 50, 51, 52, 54, 56, 57, 53, 59, 61, 61 63, 84, 65, 109, 161, 162, 163, 161, 165 ; II, 320, 321, 322 32.5, 326 Lingula, . . I, 2, 18, 88, 56, 68, 69, 62, 66, 98 Linsula .' I, 56, 62, 86 Lingula {Glottidia), . . . ' . . I, 62 Litigularitts, ...... I, 2 IJiigulasma, . 1,84,26,27,30,32,46,47,48,49,60, 62 63, 78, 81, 163 ; II, 821 Lingulella, . 1,6,7,8,19,52,55,56,57,58,69,61, 62 61, 69, 92, 162, 165 ; II, 320 hinfiulelln [Difpivmia ?) I, 66 Lingulcpis, 1,6,59,61,81, 168 Lin^idepis^ . I, 68 Linjrulops, . .1, f , 18, 19, 20, 21, 22, 23, 24, 25, 30, 82, 46 «, 48,49 61, 62, 54, 65, 158, 163, 165 ; II, 321, 822 Llorhynchus, II, 76, 193 LinnarHSonia, I, 08, 69, 70, 106, 107, 109, 113, 167, 168 11, 324 Lycophoria, 11, 830, 341 Lvttonia, . II, 313, 314 Macauilrevia, II, 289, 305 M.-igasflla, II, 305 Magellania, n, 150, 288, 289, 330 Marginifeia, . I, 330, 331, 832 Marti nia, . . II, 5, 9, 10, 11, 12, 32, 88, 40, 44, 65 Martinia, 11,3,4. 18 Martiniopsis, II, 5, 10, 34, 40, 44 MfCkella, . I, 219, 259, 262, 263, «04. 26.',, 266, 268 Megalantoris, 11, 259, 263, 877, 281 Meganteris, . . U, 2.52, 255, 277, 231 Mo;?athyrii*, II, 306 Mcntzelea, 11, 34. 40 Merixta, .11,69,70,71,72,78,76,76,77,81,82,118,828, 836 INDEX. 377 PAGE. PAGE. Merista, n, 58, 73 Orthothetes, . 218, 219, 220, 249, 253, 255, 258, 257 Meristella, n, 59, 67, 68, 71, 73, 76, 77, 78, 79, 81, 82 258, 261, 262, 268, 295 ; II, 11, 230, 337, 338, 339 101, 118, 152 OrthothrUc, I, 314 HeruteUa, . . II, 58, 59, 63, 6.5, SO Oilhotichla, . I, ai3. 226, 229 Meristina, . I I, 60, 65, 66, 67, 68. 78, 93, 118, 131, 114, 345 OstracUes, I, 146 Merinina. . II, ,■)», 59, 60 P.ilacniffia ?, I, 133 Mcsotreta, . I, 105, 109, 111 Palaeocrania, I, isa. 159 Metaplasia, II, 55 Paraatrophia, II, ai9, 221, 222, 223, 224, 227, 228, 233 Mickwitzia, I, 80, 86 239, 341 Miraulus, . . I, 270. ar«, 273, 274 ; II, 230 Parazyga, . II, 110, lar, 114, 828 SlonoboUna, . I, 60. 83, 84 I'aUUa, . . I, 146, 156, 158 Uonomerella, I, 22, 23, 28, 29, 30, 31, 34, Jo, 36, 37, 39 PateUites, . I, 155, 158 40, 41, 43, 46, 50, 53, 164, 176 Paterina, . n, 321, 326 UOblfeldtia, II, 305 Paterula, . I, 78, 165, 166, 168 Myttrophora, I, 211 Pentamerella, U, 283, 241.^2, 245, 250, 336, 341, 342 Mytaut, I, 821 Pontamerus, I, 234 ; II, 12, 72, 82, 237, 233, 236, 251 Keobolag, . I, 1, 29, 30, 80, ,84 89, 118, 165 332, 333, 336, 341 Ncwberria, . n, 253, aei, 26s, 264 Pentanterus, . II, 216, 219, 241, 249, 253, 255 Sevcberria ? . II, 277 Pentactinclla, II. 101 Xtetlingia, II, aao, 230, 341 Pentagonia, II, 80, 81 XotothjTW, . II, 260, aeS, 267, 274 PexidcIIa, . U, 108, 845 Xaclcatula II, 270 Pharetra, . I, 2 Xuclconpira, II, 64, 107, 117, 127, 128, 143, 114, 152, 328 Pholidops, . I, 1, 161, 162, 155, 156, 157, 158, 170 JVumti/iM, I, 145 n, 326 Obolella, . I, 82, 57, 58, 61, 64, 66, 68, 69, 70, 72, 73, 75 Pholidostrophia, I, 287 76, 77, 78, 80, 81, 83, 8S. 88, 89, 91, 108, 140, 164, 165 Pinna, I. 321 167, 339 ; II, 320, 322, 326 Ptesiomys, I, 196, 222, 229 ODoUUa, . I, 56, 75, 90, 107 Platidia, . II, 305 OMeUa' I, 83 Platystrophia, . I, 200, 202, 223, 229 ; II, 1 1, 182, 227 OboUUina, . I, 30, 44 229, 230 Obelus, I, 51, SI, B6, 72, 77, 90. 81, 82, 83, 84, 86 Plectsmbonites, I, 220, 236. 250. 293, 294, 395, 296 108, 139, 140, 165, 183, 837, 389 ; II, 320, 3M, 325 297, 298, 299, 300, 302, 305, 806 ; II, 337 Obolut, . I, 36, 44, 66, 83, 90, 98, 117, 118, 119 PU. 55, B8, 331, 343, . I, 180, 187, 200, 201, 204, 214, 261. II, 40, 43, 47, 61. 121, 142, 225, 227, I, 201, 211, 283, 272; II, 1, 2, 3, 4, 5, 12, IS, 18, 22, 23, 28, 51, 62, II, 11, 16, 17, 35, 69, 51, 62, SU, 836, 346 II, 8 II, 83, 84, 88, II, 98, 99, II, 112, 1.1,80,85,108,164; II, 322, 249 13 83 100 100 163 326 PAGS. I, 314 . II, 154, 137, I, 234 ; II, 187, 188, II, I, 189 192 187 137 Spondylui, , Stenoeisina, .... Stenoscbisma, Stenoscismat Stenotheca, s. g. Parmorpborella, Streptis 1,270,271,273,87* Streptis I, 272 Stieptorbynchus, . I, 219, 257, 260, 262, 265, !S67, 268 II, 337, 339 I, 47, 245, 243, 254, 259, 261, 264 . II, 233, 349, 250 1, 220 ; II, 840, 2S0, 251, 341, 842 II, 282 II, 115, »8!9 . I, 314, 315, 316, 819, 320, 330, 335 ; II, 340 I, 319, 828 1, 220, 258, 282, a84, 286, 287, 288, 289 292, 307, 311; II, 337,338, 339 . I, 47, 136, 185, 281. 285 I, 197, 220, 245, 246, 248, 250, 251, 252 265, 262, 279, 282, 286, 291, 311 ; II, 87, 323, 336 837, 338 I, 47, 187, 198, 253, 276, 277, 281, 284, 285 286, 314, 321, 328 ; II, 230, 802 I, 215, 24G, 248, 252 I, 138, 191, 220, 279, 282, 289, a09, 291 292, 296, 811 ; II, 338, 839 II, 282 I, 214, 216 1, 270 ; II, aiO, 341, 342 II, 11, 16, 30, 31, 44, 46, 47, 48, 50, 51, 63, 211 II, 289, 305, 347, 349 I, 16 ; II, 348, 349 1,110,186,200,204,211,214,269,321, 824 1, 14, 68, 62, 83, 103, 113, 113, 120, 161, 183, 185 195, 202, 203, 210, 214, 219, 225, 2.57, 265, 277 280, 290, 293, 294, 807 I, 16 ; II, 830 . I, 200, 211, 253, 267 ; II, 113, 165, 225, 293 11, 808, 209 II, 101 . II, 315, 328, 334 II, 313, 314 . I, 16, 28 1, 302 . I, 65, n, 822, 826, 327 1,87,89,92,118,131,132,138,140, 141 108, 169 ; 11, 820, 323, 824 I, 86, 87, 142 I, 80 1, 142 II, 824, 326 II, 104, 107, 108, 106, 110, la*, 126, 127 128, 272 II, 109, 127, 161, 162, 163, 164, 182, 206, 207 I, 187 StreptorhynchuSt . StricktamtiOf Stricklandinia, . Strigvcephaius^ Stiingocoplmliis, Strophalosia, Strophalotia, Stropheodouta, . Strophodonta, Slrophomcua, Strophomena, Strophotaenet, Slropbonella, Strygorephalus^ Syntrielaama, Syntrophia, Syringothyris, Tci*ebratelltt, Teiebratala, Terebratula, II, Terebratiilina, , Terebratulitts, Tercbratuloidea, Tctractinclla, Thccidca, . Theridm, Theridiurn, . Tliecospirn, Tomasina, Trematis . TrematU, . Trematit ?, TYcmatis ( Schizocrania) Trcinatobohis, Trcmatospira, Trematoxptra. Trematospira 1 Tridacna, Trigcria, . Trigonotrcta, Trigonotretat Trimerclla, I, 821 II, 865, !}73, 274, II, II, 8, 4, 22, 1,1,21,95,28,29,30,31,33,35,37, 40, 42, 43, 44, 46, 47, 43, 49, 50, 61, tfl, 53, 65, 156, 163, 164, 166 ; II 331, 322, 82.3, 276 8 28 39 113 INDEX. 379 PAGE. PAOB. TrimenOa, I, « Ungulita . I, 80 THmerella 1, I, 44 Vitulina, . II, 138, 139, 140, 805, 817 Triplecia, I, a69, 270, 271. 273, 274 ; II, 1), 214, 230 Verneuilia, U, 58 • 3S7 V'olborthia, I, 93, 9S, 96, 98, 102, 166, 167, 163 TripUtia, . I, 269 Waagenia, . I, 239 Troi>idoleptus, . I, 207, 220; II, 212, 302, 804, 305, 317, 334 Waagenella, I, 239 347, 349 Waldheimia, I, 324 ; II, 127, 301 UncineUa, II, 123 Waldheimia, 11, 108, 279, 286, 28S Uncinulina, II, 196, 197, 199, 200, 305 WhitQeWeUa, II, 68, 61, 64, 65, 78, 79, 93, 131, 160, 345 Uncinulns, II, 195 198, 199 Whitfietdia, 11, GG, 67, 73, 131 Uncites, 11,113, 114 Wilsonia, . 11, 195,196, W! Uncita, II, 282 Zygospira, II, 134, 135, 147, 148, 150, 154, 156, 156 Vftgula, . I, 80 167, 158, 160, 173, 174, 272, 344, 846, 348 III. Register of Species. (Namu in italic* are synonjnu; fignres ia foll-pacs t;pe after new species denote the plaoe of description.) Acambona Osagensis, Swallow, A. prima. White, . Acritis antiquissima, von Kichwald, Acrothele coriacea, Linnarsson, A. ? dichoioma, Walcott, A. {^nalata, Linnarswn, A. Hatlhcwi, Hartt, A. subsidua. White, Aerotreta attenuata. Meek, A. Babcl, Barrandt, A. Baileji, Matthew, A. ? COutata, Davidson, A. diectinifera, Sowerby, A. planosulcata, Phillips, A. Prinstann, liilliugs, A. lEogersi, sp. nov., A. Royssii, LeveiUe,. A. semiconcava. Wooden. A- spiriferoide:s Eaton, A. subcxpansa, Waagpn, A. sublamellosa. Hall, A. subfjuadratn. Hall, A. sabtilita, Hall, . A. sp., A. trinuclea. Hall, . A. umljonata, Billings, A. vittata. Hall II, 7 II, 132, 183, 136 II, 133, 136 II, 339 , 11, 91 II 93, 97 , II, 91 II, 90 II, 158, 159 II, 68 11, 188, 169 II, 91 II 83, 90 II, 90 II, 95 ,96, 118 II, 364 II, 91 n. 90 n. 60 II, 157, 159 II. 91 II. 90 , II. 62 , II, 90 II, 149 II, 34 , II, 96 II 88, 91 .11 92, 99 II, 64 II, 97 II, 91 II, 91 11, 89 II, 91 II. 91 II 95, 96 II, 86, 95 97, 99 II, 07 II, 91, 96 II, 64 11.89, 90 380 INDEX. PAGE. PAGE. Any,* f ifimlmm, Salter, I. 270 Atrfpa unijuleata, Conrad, U, 80, 81 A. II. 130 A. (Triplocia) apiculata, Salter, I. 271 A. otttfu. Hall. . II, 181 A. (T, ) iuccrta, Davidson, I, 271 A. amffiUa. Calllaud, . IX, '26», 281 Atryp na Clintoncnsis, sp. nov.. 11. 161, 162 A. afrimit, de Vorneuil, . . II, 111 A disparilis. Hall, 11.162, 171 A. oraia, Conruil, . 11. its A. iinbricato. Hall, n. 162, 171 A. asponi, ScUolhrim, . 11, 170, 171, 172 AulacorUynchus I'acliti, Thttmar, . . . n, 312 A. s«pcrs, rar. occidentaU«, Hall, II, 170 Aulonotrcla polita, Kuiorga, . . 1.80. 82 A. Barmtitii, Davidson, . 11, 162 A. Bculpta, Kuiorga, I. 82 A. bismUala, Kiumons, II, 62, 146. US, ISl Aulostegcs Dulhousii, Davidson,. 1. 820 A. Olrini, Ketxelroih, II, 173 A. Guaduloui)Cnsi.s, Shumard, . I, 320 A. emiara, lUll, . II. 126 A. Medlieottiunus, Wnagen, 1. 320 A. cmcaM, IJall, . U, 61 A. spondyliformis. While and St. John 1. 316, 820 A. crauirosTro, Hall, II. 60 A. variabths, von Ilelmerscu, 1. 819, 220 A. atoidts, Sowerby, . 11. 202 A. Wanghcnheimi, de Verneuil, 1. 319 A. aupidaia. Hall, . 1. 270 Avieulc ? desquariiata, Hall, I. 67 A. cyfiWrini, Hall, . n. 60 Barrandella Arcyi, sp. nov., . H, 3G8 A. dt/fa-M, Hall, . . u. 157 Barroisellu .•'ub.-iJiUulata, Meek and Worihrn I, 12, 63. 164 A. Deshajcsi, Cailtaud, . II, 261, 281 lieecli eria Davidson!, »p. nov,. U, 300 A. didytna, Dnluinn, II, 60 B. Bulj|!i'vi.<, Waagen, 11, 300 A. dafria, Hall, n, 180, 181 liillda Icpida, Goldfuss, U, 96, 131, 133 A. clUpsoidua, Xttielroilt, II, 169 liracliyprion goniiulatum, Shaltr, . I, 288 A Tiftm, Hall, . II, 149, 190, 151 B. Ledn, Billings, . I, 288 A. erfoju, KininoU8, I, 270 B. venlricosuni, Shaler, . I. 288 A. gaieaia, Daliiian, . II. 242 Branconia borussica. Gagel, . ■ n. 228 A. hemiplicata. Hall, 11, 221, 222 Calceola heteroctita, Defrauce, . U, 41, 44 A. hemisphtrriai. Hall, . u> 136 Cainarclla ? autiquata, Walcott, 11, S21 A. Mrntta, Hall, . II. 127 C. calcifcra, Billings, 270, 271 ; II, 314 A. hjslrix, Wo//, . II, 178 C. hemiplicata, Hall, 11, 222 A. imbricatn, Soim-iy, ... II, 173 c? minor, Wfdcatt, . 11, 221, 341 A. ? incerta, Davidi^oii, 1, 270 c. Pandori, Billings, II, 220 A. Monuua, d'Orbigny, . , 11, 2C3, 281 c. Volborthi, Billings, . II, «19, 220, 221, 226 A. UUrnudia, Hall, 11, 60 Camarium typum, Hall, .11.71, 72 A. imterplicaia, Sowerby, . . II, 224 Camai ophoria bisuleata, Shumard, . II. 217 A. I«M, Sowerby, . II, 251 C. caput-lestudinis. While, . II, 217 A. Itpida, Davidson, . n. 131 C. Dawsoniana, Davidson, • II. S17 A. marginall.'i. Dolman, . . U. 172, 173, 174 c. eucliaris. Hall, . U, 82, 217 A mediaits, V.Tiiuxem, . 11, 205 c. Giffonli, Worthen, . II, 217 A. modesta (Say), Hall, 11, 155 c. globulina, Phillips, . II, 216 A. nndtkosta. Hall, 11, 76 c. globulina, Davidson, . . II. 217 A. Murchisouiana, 11, 171 c. • Humblctonensis, Howse, . 11, 217 A. naviformis. Hall, 11. 60, 76, 77 c. isorhjTicha, McCoy, . 11, 217 A. mUida, Hall, 11, 68, 60 c. lenticularis, White and Whitfield, . 11, 218 A. nitida, var obtata, , 11, 60 c. rhomboidalis, xp. nov. . 11. 217 A. iKMlostriata. Hall, 11, 170, 173 c. ringens, SwrUlow, 11 217 A. nucella, Daiinan, . 11, 230 c. Schlothclmi, von Buch, 11. 217 A. nucleus, Hall, . . I, 270 c. Swallovana, Shumard, . . n. S17 A. oWa/o, Hall, . II, 60 c. Sualloviaaa, Shnmartl, II. 253 A. oboraia, Sowerby, II, 152 c. subcuneala, Hall, II, 217 A. patmata, Morris and Sharpe, 11, 137 c. sublrlgona. Meek and Worthen ■ II. 217 A. ftectini/mt, Sowerby, . 11, 00 Camarospira cucliaris, Hall, . II. 82 A. ptanoeonvexa, Hall, 11, 136 Capell inia niira, sp nov , n. %48 A. plena. Hall, . 11, 181 Cardinocrania indica. Wooden, I. 164 A. plUatula, Hall, . 11, 136 Catazyga Hcadi, Billings. II. 158 A. prunum, Dalman, II, 61 Centronella Alii, A Winchell, . II, 290 A. pseudomargmaliu, Hall, . H, 173 C. alvcata. Hall, . n. 268 A. fuadriotUla, Hall, 11. 76 C. Anna, Hartl, II, 201 A. reticalarU, Lauu. . II, 163, 168, 167, IBS, 109, 170 C. Bergeroni, (Ehlert, 11, 266, 272 171. 17-'. 173, 174, 175, 217 C. Gaudryi, (EUert, 11, 266, 273 A. nigonA, Hall, 11, 170, 171 C. glansfagea. Hall, n 267, 268, 269, 273 A. tcitula, Hall, . ■ . U, 79 C. Glaucia, Halt, . 11, 268 A. Hpinooa, Hall, . . II, 172 c. Guerangeri, II. 373 A. lumida, Dalman, 11. 67, 76 c. Hecate, Billings, . 11, 268 INDEX. 381 Centronella impressa, Hall, C. Julia, A. ■VVinchcll, . II, 258, 267, C. ? Margarida, Derby, C. virgo, Phillips, . Charionella Circe, Eillin^s, C. ? Hyale, Billings, . Chonetclla na:^uta, Wnagen, Chonetes Antiopia, Billings. C. Canadeni^is, Hillings, C. comptanata. Hall, C. concentrica, t/e Koninck, C. comuta. Hall, . C. coronata, Cornad, C. Daicsoni, Hillings, C. FiMfiari, Norwood and Pratten, C. glabra, Geinitz, C. t. VerncaUl, Boutkartl, . DmtiUnulU limfnteidu, Waagcn, D. ( :i' I jUihmina ) linernloides, Dayta navlcuUi Scwerby^ DtltkfHi tltrata, Dalman, Oerbya afflnU, sp. nor. O. Bcnnetti, sp. nov., . D. blloba, ep. nov., t>. BroadheadI, sp. nor., C. Correana, X>>rtjr, D, ? costatula, sp. nor., . D. crassa, ibek and Hafdm, D. granilis, WaagtH, D. Keokuk, Hall, . D. rcgularU, WaageH, D. robusla, Hall, . D. nii^nosa, sp. nov., Dielasnin bovidcns, SbrtoH, . D. elongatuin, SfJUotheim, D. turgidaro, JIail, Dieladminu plicata, n'aagtn, . Dinobolus Dolicmicus. Barrandt, D. Brimonti, Rouault, D. Canadensis, BUIingx, . D. Conradi, Hall, . D. Illcksi, Daridson, O. ma^ificua, Billings, D. parvus, Whitfirld, D. Schmidii, Daridson and Kinf, D. transvcrsus, Salter, D. Woodwardi, Salter, . Dioristellaindistineta, Beyrich, Diplospirclla Wissmanni, Minster Diteina aeadiea, Hartt, D. ampla, Hall, i>. .' BalrUtehensis, Davidson, D, Bohtmtea, Barrande, D. Caer/aiensis, Hicks, 0. dara, Spencer, . D. Conradi, Hall D. discus. Hall, D. Dorm,- Hall, Z>. grandis, Vanuxem, ' D. kumilis. Hall, . D. Herzeri, «p. noV., D. intermedia, Barrande, />. inutilis. Hall, . O. tametlota, Broderip, D. Lodensit, Hall, . D. Maotis, Barrande, D. Mankattaiunsis, Meek and Worthen D. marginalit, Whitfield, D. media. Hall, />. minuta. Hall, D. ilorriti, Davldson, D, Keicberryi, Hall, D. nitula, rilillips, D, ottraoides ILamarck, D. pileoltu, Uicks, . D. pleuritet. Meek, D. Randalli, Hall, . PAQB. n, 45 I, SOI I, 801 I, 88 ITaafni, I, 28 . n, 6!l H, 8 I, 349, 860 I, MS, 348 I, 350 I, 26S; 3M, 347 I, 203 I, 34e I, 203 I, 2«2 I. 262 I, 262 I, 262 I, 346 II, 29S, 301 . II. II, 297, 298, II, 298, . I, I, I, I, 38, 39, 40, 42, 43, 175, I, I, .1,39, .1,89, .1,89, . 1,89, . II, . 11, . I, I, 12S, 127, . I. 295 347 299 176 . I, I, . I, I, m, I, 126, I, 1,125, . I, 1,187, . I, . I. 1,122, I, . I, I, I, 125, I, 125, I, 125, . I, I, 125, I, 126, 126, I, 121, . I, I, 126, 181, . I, Diseina rererta, Barrande, D. rugaia, Barrande, D. sectdrns, Barrande, D. striata, SeJtumaeker D. striata, Soworby, D. tarda, Barrande, D, tenuilamellata. Hall, D, truneata, Hall, . D. (CEhlcrtcUa) pleuritcs, Meek Discinisca lamcllosa, Broderip, DiMiinolcpis granulata, Waa^en, Discinopsij Gulielinl, Matthew, Douvillina Dutertrii, Murehison, Eaton ia cmincns. Hall, £. racdialis, Vanuxem, K. peculiaris, Conrad, £. pumila, Hall, . K. singularis, Vanuxem, E. sinuata, Hall, . E. Whitncldi, Hall, Elkania desiderata, Billings, . Enteletes fun-uginous, Waagen, E. hcmiplicatus. Hall, E. I^amarcki, Fischer de Waldheim, E. pentamcroides, Waagen, Eumetria gramtieosta, E. indica, Waagen, E, punctuli/era, E. vera. Hall, £. vera, var. costata. Hall, £. Vemcuiliuna, Hail, . Eunella simulator. Hall, E. SuUivanti, Hall, GlAssia elongata, Davidson G. obovata, Sotcerby, G. Komingcri, sp, nov., . G. Whulbomii. Davidson, Glottidia Audebardi, Broderip, G. Palmeri, Datl, . Gonambonitcs lata, Pander, . Grucncwaldtia latilinguis, Schnur, Ixypidia conchidinm, Dalman Gypiduiacomis, Owen, . G. Ixviuscula, Hall, G. Lotis, Walcott, . G. mundula, Calvin, G. Romiiigeri, s]>. nov., . G. snbglobosa. Meek and Worthen, G. ungui/ormis, Ulrich, Halhna Nicolleti, Winchell and Schnchert, H. Saffbrdi, Winchell ami Sekxchert, Ilarttina Anna, Hartt, . Hemipronites alia, I'amler, H, Americana, Whitlicld, . H. apiealis, Whitfield, H, nutans, James, H. sph-xrica, Pander, II. tumiila, Pantter, Hemiptychina Himalaycnsis, Davidson, II. sublaerls, Waagen, Hipparionyx consimilaris, Vanuxem, . H. connmilii, Vanuxem, . PAGE. I, 133, 135 I, 135 I, 101 I, 122, 128, 135 I, 122 I, 185 I, 125 1, 87 I, 140 I, 131, 133, 136 I, 90 I, 106 I, 289 . II, 206 II, 20G . II, 206 . U, 206 . II, 206 . II, 206 . II, 206 1, 77 I, 216 I, 216, 217, 228 I, 214, 215, 226 U, 12 I, 216 n, 122 . II, 122 . U, 121 II, 119, 120 . II, 119 II, 117, 120, 122 . H, 290 . II, 290 . II, 153 II, 152, 153 . II, 153 . II, 153 I, 8 . I, 14, 63 I, 287 . II, 175 . II, 231 II, 243, 248 II, 242, 248 . II, 218 . II, 248 . II, 248 . II, 248 . II, 235 II, 150, 151 II, 150, 151 . II, 292 I, 238 I, 239 I, 239, 240 I, 251, 845 I, 288 I, 238 . II, 299 . II, 299 I, 2S8 1, 258 INDEX. 383 CAGE. PAGE. Hipparionyx proximus, ranuitm, . . I, 257, 258, 259 Lcptanisca adnascens, sp. nov., I, 301, 36% H. simitaris^ Vanuxem, , I, 238 L. conca\a, Hall, . I, 301 Hastedia gi'andicosta, Davidson^ . II, 122 L. tangens, sp. nov.. I, 301, 33% H. Mormoni, Mareou, II, 121, 122 Lepta;nulopsis simplex, Haupi, I, 294 Hyattella congeata, Conrad, . . II, 160 Leptobolus insignis, Hall, . I, 73, 74 H. junia, Biilings, . . II, 160 L. lepis. Halt, I, 73, 71, 75 Iphiilea bella, Billings, . . I, 97, 98 L. occUens, Hall, I, 73 I. ornatella, Linnarsson, . . I, 97, 93 Leptoccelia concava, Hall, II, 134 I. (??) snUptilis, Meek, . I, 94, 97 L. dichotoraa, Hall, II, 137 Isogramnia millcpunctata, Mwiand ITorJ/irn, . II, 312 L. flmbriata, Hall, II, 137 Kutorgina cingulata, BUlinss, . I, 67, 91, 92, 93, 94 L. llabcUitos, Conrad, . II, 136, 137, 138, 14», UI, 142 95 ; II, 326, 327 L. hemispheerica, Davidson, .11, 136 K. cingulata var. posilla, Linnarsson, . I, 91 L. palmata, Salter, . II, 140 K. Labradorica, Billings, . I, 92 , 91; U, 321, 326 L. imbricata, Hall, . II, 162 K. Latourensis, Mattlme,. I, 92, 93, 91 , 95, 233 ; II, 326 Leptodus Richthoftni, Kayser, . II, 315 K. minutusima. Hall and Whitfield, .1,94, 97 LindstroDmella aspidium, sp. nov., . I, 134, 178 K. paoDuIa, While, I, 92, 94, 95 I.ingnla acuminata, Conrad, . I, 6 K. Prospoctensis, Waleoil, .1,92, 94 L. wqualis, Hall, . I, 9 K. (?) ptcrineoidoa, Matthew, I, 91 /.. albida. Hinds, . . I, 13, 14 K. BCulptilb, Meek, .1,92, 91 I.. alveata, Hall, . I, 14, 15 K. Whitnoldi, WcUcott, . I, 92, 94 i II. 326 I.. ampla, Owen, . I, 6 Karpcn^kia conjugula, Tsrhemysekew, . n, 176 L. anatina, Lamarck, I, i. 5, 6, 7, S, 10, 11, 15 Kajscria leas, Phillips, . u, 102 17, 21, 22, S2, 49, 51, 55, 67, 60 Lacazclla racditcrranca. 11,328, 329 I.. attenuata, Soim-by, I, 6, 8, 11 Laklimina Unguloides Wangen, I, 29 L. Canadensis, Billings, . I, 24, 27 Lepitzim migina, do Vcrneuil, I, 300 1.. centrilmeat.i. Hall, . I, 15 L. alternata, Conrad, . . I, 2tt, 280, 282, 283 L. compta, si>. nov., I, 171 L. allernistriata. Hall, . 1. 282 I.. Covingtonensi.-*, Hall and Whit/ ield, . I, 8 L. analogtt, Phillips, I, 279 L. Criei, Davidson, I, 65 L. atdla, do Vcrneuil, . I, 28i L. crumcna, Phillips, . I, 6, 15 L. eaudala, Sclinur, I, 287 L. cuneata, Conrad, I, 0, 12, 15 I, 300 L. Daphne, Billings, . I, 6 L. eonvexa. Pander, I. 297 L. Davidsoni, Barrande, . I, 61 L. deeipiens, Billings, I, 2W, 298 L. flarisi, McCoy, . I, 57 L tUltoidea, Conrad, I, 282, 283 I.. deusa, Hall, I, 9, 15, 171 L. dtmitsa, Conrad, I, 2S6 J.. Delia, Hail, I, 15 L. depressa, Sowcrliy, 1,260, 279 I.. distincta, Barramte I, IS L. eyglypha, Dalman, 1,279, 296 I.. KIderi, Whii/ield, . I, 9, 11, 12, 48 L. Dutertrii, Marclitson, . I, 288 I.. epimia, Barrande, I, 18 L. fasciata, Ilall, .... I, 282 L. Feistmariteti, Barrande, I, 68 L. filiterla. Hall, .... I, 251 L. Ilabellula, sp. nov., . I, 0, 15, 172 L. inerassata, Ilall (Saffoi-d), I, 282 I.. granulala, Phillips, . I, IS, 27 L. laiieosia, Conrad, II, son L. Hawkii, liouault. . I, 6, 16 L. Hasina, Bouchard, I, 298 L. insons, Barrande, . I, 64 L. LtamUilo4nsis, Davidson, . I, S9< L. Iowcn.sis,.OK'«i, I, 8 L. Uoorii, Davidson, . I, 298 I^. lamcllata. Hall, I, 10, 12, 16, 18, 48 L. mnltirugata, iUCof, . I, 279 L. Leajna, Hall, . I, 6 L. nodulosa, Phillips, I, 279 1>? Leseuri, Jtouault, . . I 7, 9, 14, 63, 05, 161 L. r nucleata. Hall, .... 1,308, 309 L. Lewisi, Sowerby, I, 10 L. oUonga, de Vcmenll, . I, 300 I.. linguata, sp nov.. I, 173 L. oiseura, Hall, .... I, 283 L. Matthewi, Hartt, .• I, 100 L. plicotis, MrCoy, I, 279 L. Melie, Hall, . . I, 10 11, 12 L. planumbona. Hall, I, 247, 250, 251 L. membranacca, A Winchell, . . I, 61 L. rhomboidalig, WUekens, . I, 250, 279, 280, 282 L. Mosia, Hall, . I, 6 286, 287, 296 ; U, 170, 184, 339 L. Norwoodi, James, . I, 8, 19 L. ntgota, Hisinger, I, 279 L. paliformis, Hall, . I, 59, 61 L. aemiovalis, McCoj>, . . I, 279 L. paracletus, sp nov., . I, 40, 12, 17« L. tordida, Billings, 1,293, 293 I,. perovata, Hall, . . I, 6 L. tubquadrata. Hall, I, 299, 350 L pctalon, Hicks, , . I, « L. tenuicincta, McCoy, I, 300 L. pinnijormis, Owen, . I, 59 L. transversalis, Dalman, I, 297, 296, 299 L! patita, Hall, . I, 67, 72 L. unicostata. Meek and Worthen, . I, 282 L. prima, (Conrad) Hall, I, 69 L. Waltoni, Davidson, . . I, 283 L. Procteri, UMch, I, 10, 12, 15 384 INDEX Umfuit flumhtn, Salter, PAQE I, 83 I.. |iuni-UU, Hall, L. pygmasa, Salitr, L. pj/nmidum, Stiin|i8on, L. (|ua . I, 1, I. I, . I. . 1,60, 8 9 48 6 18 1B2 27 69 69 67 68 58 68 68 69 68 61 61 61 61 62 61 62 61 61 Unnargsonla pretiosa, BUlixga, Jj. misera, Billingi, L. aa^ttalig, Salter. L taconica, Watroii, L. transversa, llartt, LiorhjTichas liooncnsis, Shumard, L. globnliformis, Vanuiem, 'L. Urecnianug, Ulrieh, . L. Kelloggi, Hall, L. Laora, Billings, I~ Lesleyl, ap. nov., L. limitaria, Vanuxem, . L. mesacoslalia. Hall, . L. multicnstus, Hall, h. Newlicrr>l, //cr//nn«, . I, 69 Orisk inia navicella, sp. nov.. II, 269, 270 O. ? amhigva, Walcott, . 1,69, 78 Orihambonites transversa. Pander, I, 237 O. Beiti, Dnridson, I, 68 Orthis acutiloba, Ringueberg, . I, 205 0. ealala. Hall, I. 69 O. acutilirata, Conrad, I, 223 O. chromatica, Billingt, . I, 67, 6S, 69, 70, 72, 73, 75, 76 0. .■equivalvis. Hall, I, 194, 221 78, 91 0. alternata, Sowerby, I, 203 O. cingulata, Billings I, 69, 91 0. ulsa, Hall, I, 225 O. Circe, Billings, . . 1.68, 69 0.? apicalis, Billings, I, 217, 240 O. crassa. Hall, . . 1, 67 68,09 70,71,72,75, 78 0. arachnoidea, Phillips I, 256 0. desidtrala, BiUingg, I, 57, 69, 75 0. arcuaria, sp. nov.. I, 224 O. desqnamata. Hall, I, 68 0. Armaiida, Billings, I, 217; II, 214 O. ? dlscoUIea, Hall and WkU/itU I. 69 O. assimilis, Hall, . , I, 224 O. gemma, Billings, I, 68, 69, 70, 71 0. Aurelia, Billings, I, 221 O. ? Ida, Billings, I, 69 o. Aymara, Salter, II, 137 O. maculata. Hicks, . 1,68, 109 0. Barabuensis, A. Winchell, 11, 212 0. misera^ Billings, I. 69 o. basalis, Dalnum, I. 191,192, 207 O. nana. Meek and Hoyden, . 1,69, 70 o. Battis, Billings, I, 222 O. nitida, ford. . I.«9. 70 o. Baylii, Konault, I, 213 O Pliillipsi, HoU, I. 94 o. bellarngosa. Hall, I, 222 O. poUta, Hall, 1,68 89, 70, 72, 73, 83 o. bcllula, James, . I, 224 O. preliosa, Billings, I, 70 o. biforata, von Sehlotheim, I, 190, 200, 223 0. Sabrinx, Callaway, . 1.68. 103 0. Billingsi, llartt. I, 232 0. sofiualu, Salter, I, 68, 107, 108 0. Billingsi, Safford, I, 219 O. trasunrsa, Harll, . 1,70, 107 o. biloba, Linni, . . . I, 190, a04, ;05, 223 OMtu advemt, Barrandc, • 1,68, 69 0. bisulcata, Emmons, II, 146 O. antiqnUsimu^, von Eichwald, I. 82 o. borealis, Billings, I, 222 O. ApoUinis, von Eichwald, 1,51,80,82, 339 0. Bouchardi, Davidson, . I, 217 O. Appolinus^ Owen, I, 72 0. Burlingtoncnsis, Hall, I, 225 0. .» Bohemicns, liarrando, . I, 101 o. callactis. Dolman, I, 191, 192, 195, 196, 228; II, 133 0 t compUrus, Barrandc, . . 1,68, 73 338, 340 0. ingricns, von Eichwald, . I. 82 o. calligramma. Dolman, 1,190,191,192,193,194, 195 I, M ; n. 821 219,231,238,242, 244 O. pnUher, Matthew, . 1,81, 183 o. calligramma, var. Davidsoni, de Verneuil, 1, 193, 227 O. Qnenstedti, Mickwitz, I, 1139 0. ealligramma, var. JIabelliles, Foersto, . I, 228 O. silaricus von Eichwtdd, I. 82 o. calligramma, var. orihambonites, Billings, . I, 221 (Elilcrtclla plearites. Meek, • 1, 1«, 169 o. carinata. Hall, ... I, 213, 226 Oldhainina dccipicns, de Koninck, II, 814 o. circularis, Roemer, I, 259 Oriieula antiqmssima, von Eichwald, I, 118, 119, 140 o. circulus. Hall, . I, 210, 224 0. Bucks, do Verncuil, . I, 1.-.I, 192 0. Clarkensis, Swallow, I, 225 O. caltJa, Hall, I, 69 0. Cloobis, Hall, . I, 225 0. erasta, Uall, I, 72 o. Clytic, Hall, . . I, 202, 203, 223 0. deformata. Hall, . I, 150 0. concinna, HaU, I, 207, 224 O. Uorrisi, Davidson, I 128, U'9, 130, 160 0. coral Una, Waagen, I, 210 0. norvegicOf Sowerby, I. 121 0. Corinna, Billings, I, 217 O. norvegica, Lamarck, I. 122 0. costalis. Hall, . . I, 221, 227, 228; II, 340 0. fitnctata, Sowerby, I. 140 0. crassa, Meek, I, 223 0. rnersa, de Vemeull, . I. 118 0. eremstria. Philips, I, 248 0. ? squami/ormis^ll&U, I, 159 0. crispata, Emmons, I, 224 O. lerminalis, Emmons, I, 140 o. Cumberland i.i. Hall, I, 225 Orbicoloidea, sp. ? Meek, I. 127 0. cuneata, Owen, . I, 225 O. eontea, D wight, . 1, 116, 124, 126, 129, 135 o cvclas. Hall, I, 2-25 O. Davidsoni, d'Orbigny, . I. 160 o. cylindrica, McCoy, • I, 262 386 INDEX. PAOE. I OlthU Dalynnii, Jfi«€rg, .1,207, 224 o. o. lontlrunnis, HaU, I. 224 o. 0. Leouensls, Hall, I, 224 0. 0. lepida, HaU, . .1,207, 221 0. I Loncosia, Halt, , Upida, Sclmur, . Linntyi, Xcttclroth, Llvia, BiUings, . Loiiensis, Walcott, loricula, sp. nov., Lucia, Billings, . lyn.\, ron Ficltwald, Uacrui'lauii, Meek, Macleoili, Wkitfiel,!, Maria, Billings, marmorca, Waagen, Mccki, Miller, . Merope, liillings, Miciiclini, Leveille, mimica, Barrandt, Minneapolis, A^. H. Winehell, Missouricnsis, Sicallow, Jloiganianii, Derby, multisecta, Meek, multii^triata, Hall, musculosu, Hall, Mycale, Billings, Nevadensis, Meek, Nisis, Hall, oblata, Hall, . occasus, Hall, . occidcntalis. Hall, Olivieriana, dc Vcmeuil, Orl)ignyi, Davidson, orthambonites, Billings, Owcni, sp. nov., paltnata, Salter, Pandcriana, sp. nov. Pecosi, Marcou, . peeten, Dalman, . pectinclla, Emmons, pcctinclla, Emmons, v pcduncularis. Hall, Peloris, Hall, . Penelope, Hall, Penniana, Derby, Pennsylvanica, Simpson, Peptna, Hall, pcrclegans. Hall, pervcta, Conrad, planoconvexa, Hall, platys, Billings, plicatella, Hall, porcat.a, McCoy, prava, Hall, productoides, Murchison, propinqua. Hall, punctata, Hall, punctostriata, . Quaroensis, Matthew, (juadrans, Hall, (juadricostata, Vanu-rem, recta, Conrad, resupinata, Martin, re»upiuoidcs, Cox, rctrorsa, Salter, retrorsislria, McCoy, I, 225 .1,269, 260 U, 181 1, 225 1, 222 1,107,222; 11,833, 337 1, 225 11,202, 223 1,190,212, 226 I, 224 I, 222 I, 214 1,206,207. 224 I, 242 194,219,225, 343 I, 200 I, 224 I, 225 218,214,216, 226 . 1, 207, 224 . I, 212, 226 1,190,210,211,225, 258 . I, 217, 232 I, 226 I, 217 1,210,224, 225 I, 225 . I, 202, 222 I, 266 1, 283 .1,221, 228 I, 225 II, 138 Expl. Plivto 1 I, 210, 225, 226 I. I, 195, 196, 222, ar. semlovalis, H(ai, 1, 222, I, .1,225, • 1,211, . I, 210, I, . I, 230, .1,207, .1,207, .1,207, I. 1, 194, 196, . 1, 197, I, I, 1, 212, 1, I, . I. I, II, I, 199,211,213, 1, 213, I, 197, . I, 191 228 2-28 226 343 225 228 225 232 224 224 224 218 221 222 225 317 226 217 217 232 224 19:i 222 220 226 222 208 INDEX. 387 PASS. PAQE. Orthis rcversa, Salter, , I, 197 Orthothetes pectcn, Dalman, . I, 330 0. robmta, Hall, I, 263 0. radiata, Fischer, I, 256 O. rogiplicaia. Hall, I, 217 0. socialis, Fischer, I, 256 O Saffonli, sp. nov.. I, 218, 340 0. subplanus, Conrad, I, 256 O. ScoviUii, Miller, I. 222 0. umbraculum, von Buck, .1,259, 345 O. sectostriata, I, 221 I*arastroi»hLa Greenii, sp. nov., n, 222, 367 O. Semc\e,HaU, . I, 223 P. divergens, sp. nov., , 11, 222, 386 0. senecta, sp nov.. I, 226 P. latiplicata, sp. nov., . . II, 222, 2J3, 368 O. sinaata, Hnll, . I, 198, 212 P. multiplicata, sp. nov.. II, 222, 2-23, 367 o. SOcialU, BarrantU, I, 200 Parazyga Deweyi, Hall, 11,128,129, U4 o. solitaria Hall, . I, 225 P. hiisuta, Hall, . U, 111,128, 129 0. spiri/erouUs, McCoy, . I, 271 Patella anomaia, MUUer, . I, 122, 150 o. Stonensis, Safford, I, 221 P. antiqua, Schlotheim, . I, 153 0. ttriatflta, Dalman, I, I'Jl, 305 P. implicata, Sowerby, I, 158 o. strtatula, Schlotheim, . I, 213 Paterina Swantononsis, \Valcott II, 321 o. strophomcnoiiics, Halt, . 1, 199, 223 Paterula Bohcmica, Barrande, I, 79 o. sabaequata, Conrad, . I, IW, 207, 221 Pentagonia Peersi, Cozzens, II, 80 o. Bubcarinata, Hall, I, 207, 321 P. unlsulcata, Conrad, II, 81 o. subelliptica, ir^itranil Whitfield, I, 225 P. unlsulcata, var. biplicata. Hall, . II, 81 o. guborbicularl.^, Hall, , I. 225 P. unistilcata, var. unipticata, Hall, . II, 81 o. subquailrata, Hall, . I 191, 196, 197, 311 PentameroUa arala, Conrad, . II, 212, 215 o. Bopcrstcs, sp. nov., I, 217, 224 P. dubia. Halt, II, 243, 215 o. Swallovi. Hall, I, 213, 226 P. micula, HaH, . . II, 245 0. Swccncyi, N. H. Winclull, . I, 190, 2.>2, 228 P obsolescens. Hall, . II, 245 o. tcstadinaria. Dolman, I, 190, 1»1 , 192, 203, 206, 207 P. papilionensis, Hall, II, 245 217, 218, 224 P. Pavilionensis, ifa/i, . . 11, 245 o. tctragona, I. 219 Penlamerus Areyi, sp. nov.. II, 242, 248 0. Thiemii, Whilt, I, 225 P. AyUsforili, Sowerby, . II, 236 o. Tioga, Hnll, I, 212, 226 P. Barramtii, Billings, II, 244 o. trlccnaria, Conrail, I, 191, 193, 221 P, Bashkiricus, de Verncuil, . II, 235 0. triplb-atclla, Mtek, I, 191, 221 P. bl.-lnuatus, McChesney, II, 239, 239 o. Tritonia, Billings, I, 217, 232 P. borcalis, Eichmtld, . 11,234, 240 0. tubulostriata. Hall, I, 210, 225 P. Colteiti, -Miller, . II, 235 o. Tulliensis, Halt, I, 212, 226 P. comptanaius, Xettelrolh, II, 235 0. uticrU, Billinfs, I, 224 P. crassicosta. Hall and AVhitfleld, . II, 235 0. umbonata, Conrad, II, 55 P. cylindricus, Hall, 11, 237, 238 0. i»nirari<_ KuydVoiiu, Ncttelroth, p. rtnlrimstu. Hall, p. rai, Hall, . PcxUlclla Slrohmayeri, Sum, Pholidops antiqua, SfUoikrim, p. arenarla, Hall, ■ belluU, Walcoii, calccola, ep. nov., ClncinnatlcnsU, Ho/I, namiltonln, Hall, impUcata, Sobw**, lepis, ep now, . linsruloidcs. Halt, oblata. Ball, ovalis, HaU, orata Ball, patina, sp. nor., sp. ? ■ sqaamtformis. Ball, . tenninalis, Ball, TrentoncnsU, Ball, INDEX. p. p. p. p. p. p. p. p. p. p. p. p. p. p. p. PlecUmbonitcs crassa. Pander, p. oblonga. Pander, p, ovata, Pander, . p. plauUsima, Pander, p. produeta, Bp. nov., p. lestudinata, Pander, . p. transversalis, WaUen/xrg, pliailHla slriittocostata. Cox, Polvtoschia apicalis, Wliitfield, Por'ambonilcs intermedia, Fandrr, p. obscums. Ball and Whiiftrld, p_ Ottauneiisa, Billings, . Pndueta analoga, I'hillipS, p. modesta, (Say) Hall, . p. monUi/era, McCoy, p. ngoio, Uiainger, p. truneata. Hall, > p. (Tripl'cia) nwnili/era, McCoy PraiueteUa ky$tricula, Hall, Productos OHjuicostatus, Ball, p. equlradiatus, Skumard, p. altematos, Narteood and Pratitn, p. Altonensis, Norwood and Pratten, p. Americanus, SunJ/ow, p. arcnata.4. Hall, . p. asper, McChesnejf, p. blseriatos, -Ho", p. Barlingtonensis, Hall, p. Chestorcnsis, iroi-i*«)i, p! Chriatlan i , d« Koninek, . r. clavoi, Norwood and Pratten, p. cvmoiiiu, Sowerby, p. comploctens, Eiheridge, p. compresso*, Waagen, . p. Cora, d'Orbigny, p. coDtatus, Sowerby, p. ditiimilU, Hall, . p. cnnineua, d< ifoaiiKir, . p. Gcinitzinnu.i, e/e Konindc, p. genuinos, Kitforjo, PASB. . II. SS5 H, »» . H, 2« II, 843, 243, «t4 II. 32* U, KB I, 157, 15B n, S25 I, 157 1, 157, 18a I, 157, 159 157, 159; 11, S26 I, 167, 159 I, 157 I, 157;n, m I, 157 I. 157 I, 157, 159 I, »«• I, 159 I, 156, 159 I, 157 1, 157, 159 I, 297, 29S I, 300 I, 300 I, 296, 297, 298 II, 360 I, 297 I, 29S, 299 I, 205 I, 239 II, 226 II, 228 II, 228 I, 280 II, 155, 157 I, 270 I, «9 I, 316 I, 271 I, 316 I, 326 I, 826 I, 827 I, 327 I, 326 I, 327 I, 837 I, 827 I, 327 I, 827 I, 827 I, 334 I, 317, 818 1, 316, 885 I, 826 I, 826 I, 827 I, 832 I, 834 I, »27 I, 884 Productus HaUiama, Walcott, PAoa, P. honidos, Smcerby, p. Lasallensis, Worthen, . p. lanullosvs, Sandbergcr, p, latirostratus, llowse, . p. leonhnrdi, Wissmann, . P. UangolUnsis, Uiividson, p. longispinus, Sotperby, . p. raagnus, Meek and Worthen, p. inarginicinctus, Prout, p. Martini, Sowerby, p. mesolobus, Phillips, p. mytiloidca, Wangen, p. Nebrascensis, Owen, . p. Ncwberryi, Hall, p. nodosus, Newberry, P. Kystianus, de Konimk, p. opantia, Waagen, p. ovatns. Hall, p. pileiformis, Newberry, . p. I'rattenianus, Norwooil, p. proboscideus, de Veineuil, p. punctatus, Martin, p. Kogersi, Norwood and Pratten p. Bcabriculus, Martin, . p. Bemircticulatus, Martin, p. splendens, Norunod and Prati p. Btriatus. Fischer, p, subaeuleatus, Murchison, p. Bulcatus, Castelnau, p. Bymmetricus, McChesney, p. tenuicostatus, Hall, p. umbonillalus, Davidson, p vittatus. Hall, . p W'ortlicni, Hall, p. (DaviesicUa) LlangoUcnsis, Daividson, p (Etheridgina)complecten8, ElAeridi'c!, p (Proboscidella) proboscidcus, de Verneuil, I. I. I, 327. II. I, I. I, 317, I, 816, I. I- I. I, I. I, 263, 325, I. I. I, I. I. I, I, I, 326, 333, I. I, I. I, 325, 327, I, I, 326, I, 317, I. SS2 327 S32 ISO SSO 8M 818 332 827 (27 825 827 Pronites adscemUns, Pander, p. humilis. Pander, .p. oblonga. Pander, p. (Clitambonites) adsccndens Protorhyncha dubia, Hall, Protozyga cxigua, Kofi, Ptychospira ferita, con Buch, . Kaflnesquina alternata. Conrad, R. expunea, Sotverby, R. Jukesi, Davidson, Rcnsselairia ajquiradiala, Conrail, R. Cayuga, sp. nov., j{. Condani, McChesney, . R. Cumberlandiac, Hall, . R. clUlitica, HaJi, . j{. ? Johannis, Hall, . j{. lavis. Hall, R. lowu, Meek, R. Marylandica, Hall, B. mutabilis. Ball, R. ovoidcs, Eaton, . B Portlandica, IJlllings, . B. Sucssana, Hall, . Retzia Adrieni, de Vemeuil, . R, ignini/ormis. Hall, 234,235, I, I, Pander, I> II. II, II, I, 250, I. II. II. II. II. . II. II. II, 262, 26S U, 257, 284 II, 264 . II, 258 II, 258, 259, 260, 297 il, 245, 258, 259, 262, 349 II, 278 II. 259, 260, 266 il, 106, 107, 108, 110, 121 . U, HI 827 82* 326 834 827 8S« 826 326 884 827 827 827 834 828 260 827 827 320 827 827 317 335 333 237 238 238 238 181 119 113 286 250 339 258 258 280 258 INDEX. 389 Sttzia carbonaria, Davidson, R. compressa. Meek, R. Davidsoni, (le Koninck, R, Eugenia, Biliings, R. granuii/era. Meek, R. intermedia, de Koninck, S. lepida, Kayscr, . R. longirostrisi Kayser, R, Meekana, Sbumard, R. OsagensiSf Swallow, R. papillata, ShumarU, R. punctttlifera^ Shumard, R. radialis, Phillips, R. serpentina, erlamcllosus. Halt, . perplexus, McChesney, . ptanoeonverus, Shamard, plcnus, Halt, pliratcllus, Dalmam, rlulo, Ctarlct, porambonites, vou Buch, praematuros, Hall, , propinquut, Hall, psoudoUncatos, Hall, pyxitatus. Hall, Quichuu, d'Orbigny, radlatus, Souxrby, raricosta, Conrad, rostellatas, Halt, rostellum. Halt &niiWliiffitld, . Saffordi, Halt, . Schmidli, Lindstram, 6CaIptills, Halt, . scgincntus, Hall, tenilis, Phillips, BCtigerus, Hall, . limplex, Phillips, sp. indcs., Btriatiformls, Meek, striattts, Martin, sabiBqualis, Hall, subattcnuatus. Hall, sabcarrliiformis, ^oit, . tubcuspidalus. Hall, ■ubmucronatus, Halt, , H, • n. .11, .11, .11, .n, .n .II, ■ II, 11,9, 11,14, 17, 34, 31, 29, 85, 25, II, II, 16, ". II, 26, 11, 2fi, 23, 17, II, 361 II, 126 .II, .II, .11, ■ II, .II, •II. .II. .II. 11,29, 11,29, II, U, .II. II, 31, . II II. 31, 26, U, li, II. II. 19, 17, 27, 12. II. 31, 31, 26, 21. II. .II, •II. • II. . II, • II. .II. .11, • n, U, 39 II, 227 II. 87 60 37 56 276 33 36 26 35 36 SS 36 2o .11. . 8, 10, 21, . II, 26, 86 . 11, 17, 36 . II, 26, 88 PASB. .n, 17, Spirifer saborbicularis. Hall, . S. subrotundatus, Hall, , S. subunibona. Hall, S: subundiferus, Meek and irorthen, S. sulcatus, Hisinger, S. tegulatus, Trautschold, S. tenuicostatus, Hall, S. tennimargin.itus, Hall, S. texanus. Meek, . S. (ex«««, Hall, jS. transversus, McChesney, S. tribulis. Hall, S. TscUeffkini, de Verueuil, S. TuUius, J7aiJ, . 8. undiferus, F. Jtoemer, S. unicus. Hall, S. urbanus, Calvin, S. Vanuxemi, Hall, S. varicosus, Conrad, S. ventricosus. Hall, S. ? IToWroncjisw, Miller and Dyer, S. Whitneyi, Hall, 3. Williamsi, sp. nov , S. Worthcnanus, Schuchert, S. Wortheni, Hall, S. zic-zac, Hall, S. {Cyrtial) //an?ii6a/«MSt«, Swallow, 3. (Syringotliyris) Carteri, HaZl, Spiriferina austriac.a. Suets, . S. BiUingsi, Skumanl, 8. binacut.a, Winrlull, S. Clarksvillensls, WinchM, S. cristata, Sclilotlieim, 8. cristata, var. octoplicata, 8. in.sculpta, Phillips, S. Kentuckiensis, Snumard, 8. Kentuckiensis, var. propatula, Sivtii S. Kocssenensis, Zugmayer, 8. rostrata, Schlotlieim, S. solidirostris. White, 8, spinosa, Norwood an3 189 374 252 262 268 392 INDEX. Sinrlarl^mehMM ermlttrta, rar. tatat; 1 A. etusrcns, AMek, 8. lUUiuiiu, Dtrbg, 8. incnmu, JMeh, 8 t ttpidus, Srhnar, 8. occiiU'iitnlU, XewbtnTi, 8. Pandora, Hilling, S. pccliiiironnis, Daridton, S. pelaivonatua, Schlotheim, 8.1 primordlale,vnMap\il, S. pjTamlilalU, A'«ie* 8. Arelhuta. XiiWinga, 8. t BalcUtchrmU, DaviiUon, 8. brevis, IiiUing>, . B. Canadonsiit, Billings. . S. caatcllana, Whiie, 8. Dariilsoni, Billings, S. d^ormis, Jlook and Worthen, S. (iaspcnsls, Billings. . S. Mulissa, Billings, 8. multilirata, IFhil/ield, . a. 8all«ri, Billings, Stringoceplialos Burtini, Dtfrance, 8, Boheniicus, Barrande, Strophalosia cxcarata, Geinitz, 8. Goliirussi, iraiistcr, 8. Keokuk, Beechtr, 8. lamellosa, Geinitz, 8. Leplayi, Geinitz, 8. namularis, A. IFinchell, 8. parra, King, 8. plicosa, Waagen, S. rad leans, A. Winchell, . S. Eockfordcnsis, sp. nov., 8. scintilla, Beeeher, Stropheodonta arcuata. Hall, . 8. Bccki, BaU, 8. Blainvillii, Billings, . 8. Calvlni, Miller, . 8. Canace, Jlall and trhUfield, 8. Caj-uta, Hall, . 8. dcmissa, Conrad, 8. fllosa, Davidson, 8. imeqaUtriata, llnU, 8. Irene, Billings, . 8. Junia, Anil, 8. I^blancl, Itouautt, , 8. magniflca, 77aU, S. magniventra, Hall, S. nacrea. Hall, 8. perplana, Conrad, 8. prorunda. Sail, . 8. - textile, Hall, . 8. Tullia, BiUings, 8. variabilis, CalHn, 8trophodonta/a*eiata, Ilall, . ,5. ((r0, 252 Slrophomena camerata, Hall, -. S. carifutta, Conrad, S. Chemungensis, Conrad, S. ctattsa, lie Vemeail, . S. Conradl, sp. nov,, S'. deflecta, Conrad, S. depressa, Dalman, S. Dutertrii, Maroliison, . 5. euglypha, Dalman, S. expansa, Sowerby, S. explatmta, Sowerby, . S. JUosa, Sowerby, . S. lluctuosa, Billings, S. funiculatn, J/cCoy, S. grandis, Sowerby, 3. llallio, Miller, . S. Hecuba, BiUings, S. Uendersoni, Davidson, S. notli, Davidson, S. Jukesi, Davidson, S. Kingi, Whitfield, S. laticosta, Conrad, S. Leblanci, Uouault, S. Leda, liillings, . 5. lepis, lironn, S. Minnesotensia, K. H. Winchell, S. Narnjoana, de Vemeuil S. nitem, Billings, . S. ? palnia, Kayser, . S. patenta. Hall, . S. pecten, Dalman, S. rhilomela, Billings, S. planoconvoxa, Ball, . S. planumbona, Ball, S. recta, Conrad, . 5. rhomboidalis, Wilckens, S. rugosa, Ilisinger, S. SUuriana, Davidson, . S. sinuuta, Knimons, S. squamula, James, S. Steini, Kayser, . S. subplana, Conrad, S. subtoiitu, Conrad, S. Thalia, liillings, 5. Vlrichi, James, 5. unicostata, Meek and Worthcn, S. Winchelli, sp. nov., S. Wisconsinensis, Whitfield, S Woolaorthana, Hall, . S. (Lept;ena) planumbona, BaU, Strophomenes fiexilis, liaflnesquc, S. levigata, Ballnesquc, Strophonella ampla, Ball, S. c.'elata, BaXl, S. cavnmbona, BaU. 8. Conradi, Hall, . S. costatula, sp. nov., 8. euglypba, Dalman, S. funiculata, Sowerby, S. Hcadlcyana, BaU, S. Lcavenworthana, BaU, S. patenta, Ball, . 8. pouctulifcra, Conrad, ,247, I, 282 II, 304 I, 255 I, 287 I, 34« I, 197 I, 249 I, 249 1, 249 I. 249 I, 288 1,249, 288 I, 251 I, 249 I, 24» I, 25S I, 253 I, 288 I, 28S I, 28S I, 283 I, 306 I, 287 I, 288 I. 287 I, 283 I, 287 I, 283 I, 288 I, 291 r, 249 I, 288 1,249, 251 1,219, 265 I. 197 18,249, 250 1.250,251, 252 I, 283 I, 251 I, 283 I, 288 I, 286 I, S51 I, 251 I, 283 I, 282 1,344 I, 251 I, 255 1,249, 262 248,249, 252 1,248, 252 1,291, 293 1,291, 293 1,291, 292 I, 292 II, 359 1,260, 292 1,259, 292 I, 292 1,291, 293 1,291, 292 1,291, 292 I, INDEX. 393 Strophonclla radiata, BaU, S reversa. Hall, S semifasciatu. HaU, . S. striata, riall. Synirielatma hemiplicatum, JIall, Syntrophia lateralis, JFhitfield, SjTingothyris angulata, Simpson, 8. Carter!, Ball, . S. cuspida'.a, Martin, 8. dletans, McCoy, S. Halli, mnckell, . s. llerricki, Schuchert, . s. Missouri, sp. nov.. 8. Bandalli, Simpson, 8. tcxta, BaU, 8. typa, A. Winchdl, Terebratula Adrieni, dv Verneuil, T. amyffdalina, Goldl'uss, T. Andii, d'Orbigny, T. Antisiensit, d'Orbigny, T. Archiaci, d« Vemcail,. T. bovidena, Morton, T. Iturlinyionensi*, While, T concentrica, von Boch, T. cuneata, Dalman, T. d^fiexa, Sowcrby, T. dUlyma, Dalman, T. ferita^ von Buch, T. formoaa. Hall, . T. Caudr^f, d'Orbigny, . T. Geinitziana, de Verneuil, T Guerangeri, de Verneuil, T. Barmonia, llall, T. Bimalayemis, Davidson, T. hercale.1, Barrande, . T. louxntii, Calvin, T Unvimcula, Sowerby, . T. latilinffuit, Schnur, . T. Unt, llaU, T. lepida, Goldfoss, T. Uncklceni, Ilall, T. melonica, Barrande, . T. J/tcAeiini, dOrbigny,. T. miUipunctata, Hall, . T Mormoni, Marcou, T. navieula, Sowerby, . T. ovoidet, Eaton, . T. planirostra. Hall, T. rectirostra. Hall, T rhomboidea, Phillips, . T, Romingeri, Hall, T. Bimleyi, Worthen, T. Bacculiu, Martin, T. Scklolheimi, von Buch, T. simulator. Hall, T. Stokesi, Kocnig, T. Stricklandi, Sowerby, T. strigiceps, K. Rocmer, T. ntblepida, do Verneuil, T. subcfscicularit, Davidson, T. Sullivanti, Hall, T. turgida. Hall, . T. teMUta, Schnur, PAGE. FAGB. I. 292 Terebratula lescicutaris, de Koninok, U, 294 . I, 291, 293 T ofrjo, Phillips II, 274 .1,291, 292 Terebratulina septentrionalis, JAnne, I, 16; 11, 328 • I, 291, 292 TerebratalUes cequiroatria, Schlotheim, II, 227 I, 216 T. bi/oratus, Schlotheim, • . I, 200, 20 . II. 213 r. elongatus, Schlotheim, . II, 294 . II, 50 T. gryphus, Schlotheuu, . . II, 111 11, 60 T. pelargonatus, Schlotheim, I, 267 II, 50 T. rostratiis. Schlotheim, " . . II, 52 II, 50 T. Schlotlicimi, von Buch, II, 216 II, 51 TerebratuloiJea Davidsoni, Waagen, . n, 209 II, 50 Tetractiuella trigonella, Schlotheim, . II, 100 II, 50 Thccidea Jlediterranea, Kowalevski, . II, 328 II, 50 Trematis Jlohemica,lja.rrnin\c, . 1,40, 142 . n. 50 T. canccllata, Sowerby, . I, 14-3 U, 8, 48, 50 T. corona, Salter, . I, 142 11, 103, 104, 273 T. crassipuncta, Ulrich, . I, 143 11,264 281 T. Dyeri, MUter. . I, 112 I. 217 T. fragilis, Ulrich, I, 142 II, 276 T. Huronensis, Billings, . I, 111 . II. 2S0 T. millepunctata, Ball, . . 1, 1S9, 142 II. 291 T. Moutrealeusis, Billings, I, 112 . II. 296 T. oblata, Ulrich, . I, 141 . n, 87, 90 T. Ottawaensis, Billings, .1,139, lU . u. 186 T. 1 pannulus, White, I, 91 II, 2-24 T. punctata. Sowerby, I, 141 II, 60 T. punctoitriatu. Bali, . I, 142 II. 112 T. pustulosa. Ball, I, 112 • 11. 296 T quiucuncialis, MiUer and Dyer, I, 112 I, m ; II, 273 n T. rudis, Ball, .1,112, 144 II, 210 T. terrainalis, Emmons, . 1, 139, 140, 142 '. U 268, 260, 267, 272 T. umbouala, Ulrich, I, 139 . II. 290 T. (Schizocrania) superincreta, Barre tt. . I, 144 . II, 299 Trcmatobolis insignis, Matthew, II. 324 n. 71 Trematoapira Acadia, Ball, . . II, 127 . u. 297 T. camura. Ball, . . • . 11, 128 . II, 97 T. coata:a, Ball, . II, 126 II, 175 T. Deweyi, Hall, . II, 128 II, 286 T. dubia, Billings, . II, 126 11,130 131, 133, 131, 135 T. gibboaa. Ball, , . II, 127 U, 286, 290, 296 T. Hippolyte, Billings, . II, 126 II. 288 T. hirsuta, Hall, . H, 127, 128 I. 217 T. inl'requcns, Walcott, . . 11. 127 . II. 301 T. linioacula, ^ WincheU, II, 127 II, 120 T. Maria, BUlings, II, 126 • II. 62 T. Matthcwjoni, McChesney, . . II, 127 . II. 287 T. multistriata, Ball, II, 126, 1'27 II. 286 T. nobilis. Hall, . . n, 127 11, 286 T. pcrl'orata, Ball, n, 126 II, 216, 217 T, quadriplicata. Miller, . II, 186 II, 297 T. simplex. Ball, . II, 126 11, 296 Trigeria Guerangeri, de Verneuil, . II, 273 II, 300 Trimerella acuminata, Billings, .1,36, 36 . II, 187 T. BilUngbi, Dall, . II, 35, 36 . II, 290 T. Dalli,X»ot)i'rf»onaMil A'insr, . I, 85 . n. 8 T. grandis, Billings I, 34, 35, 36 . u. 199 T. Lindstroemi, Dall, .1,34,36; II, 322 . II, 2C0 T. Ohioensis, Meek, I, 34, 35, 36 II. 102 T. Wisbyensis, Davidson and King, I, 36 II, 275 Triplecia extans, Emmons, . I, 270, 271, 273 . II, 290 T. Ortoni, Meek, . . 1,268,270, 271 II, 294 Triplesia cuspidata, Ball, I, 271 . 11,130,131, 134 T. ? GrayiaB, Davidson, .1,270, 271 394 INDEX. IHiiaifa tataraib, Whitfleld, T. Maoooyann, Daridton, T. noclena. Ball, ■ T. prtmorOiaU: Wliltllekl, r. ptUUltu. Ila:l, . T. ntditila, Whit/ldd. T. Wcnlocki-nsis. Datidton. TropMoIeptiu rarinatus, Conrad, T. occklcns, ItaU, Dncinella Indira, Waagtn, Uncinulina fkllaciosa, liaylt, . Unclnuliu gnbWUsoni, d'Orbing, Unciteii carbonarius, Quenstedt, V. Galloisi, (Ehlert, tl. gryphus, Scklotkeim, . U. lavUy JUcCojr, . TitDlina pastalona, Batl, Volborthia recui-va, Kutorga, PAGE. . II,21S,S1S, JSl I, 270 I, 871 I. sn ; II, 3U I, 272 1, 271 I. 270 . 1, 148 ; 11, 137. 138, 140 SM, SOS II, 80« 11, 119, 123 11, 108 II, 199 II, lU U, 115 u, m U, 115 II, 137, 188, 139 Ul . I. 95 PAOE. Whltfleldella cjllndrlia, Ball, .11. 61 W. intermedia, Ball II, 61, 160 W. naviformia. Ball II, 100 W. niti.la, Ball, . .II, 61 Waldhetmla/ormota, Hall, ■ II. 110 jr. globosa, Hall U, 111 W. recliroHra, Hall, . . .II. Ill W. Deiceyi, Hall II, 128 Zdimir solut . Barrandc, . . . .II, 235 Zygotpiral afutta, Sardeson, . .II, 150 Z. Cincinnaticnsis, Jl/eeJl-, . II, 156, 157 Z. conccntiica, Ulrich, . . .II. 157 Z. erratica, BaU, . . II, 157, 169 Z. Kentackicnsi.s, James, . II, 156, 157 Z. minima, Billings, ■ H. 157 Z. modesta, (Say) flaii, . II, 155, 166, 187, l.W, 163 Z. paupcra. Hillings, . II, 157 Z. patUla, sp. nov , . . U, 157, 365 Z. recurriroBlra, Ball, ... II. 161, 156 Z. Upbami, WiiicheU and Sdaukai, . II, 157 PLATES AND EXPLANATIONS. Fig. 1. Pijr. 2. Fig. 3. Fig. 4. PLATE XXI. (rigures 1-39 by II. P. Whitkikld.) hegtaui : A. Uelthyrium. c. Ci-ura. D. Delti.iium. s- Median septum. t. Teeth. s'. Callosity iii the ilelthyrimn. d. Dental plates. x. Crural lidges. j. Canlinal pmcess r. Diiluctor Boara. b. Denliil sockets. Genus SPIRIFER, Sowerbv. Pagre 1. Spirifeb Niaoakensis, Coiiiiid. A medium sized specimen ; showing the railiate-lineate exterior. The interior of the cardinal portion of a brachial valve ; showing the crural plates. A portion of the interior of the pedicle-valve ; showing the elongate muscular area. The median jwrtion of the cardinal areas of conjoined valves ; showing the deltia«;e I. SriKiFEK Owen I, Hull. Dorfial view of a normal adidt. A profile of the same. The interior of the cardinal portion of a brachial valve j showing the dental sockets and socket- walls. Fig. 4. A portion of the interior of the jiedicle-valve ; showing the apical callosity, and the scar of the diductor muscles. Fijf. 6. A corresponding portion of a smaller shell of this species. Fig. 6. The interior of the cardinal portion of two valves in articulation, the pedicle-valve lying beneath. Fig. 7. An enlargement of the surface from a worn specimen. Hamilton group- Clarke county, Indiana. SriBirEK Paukyanus, Hall. Fig. 8. The usual form of the shell ; the cardinal area being foreshortened. Fig. 9. An enlargement of the surface charactei-s. Limestones of the Hamilton group. Davenport, Iowa. Figs. 15, 16. Two views of an internal cast. This is the condition of the shell which has been known as S. capax. Hall. Fig. 17. An enlargement of surface strise, in a woin sjiecimen. Sandstones of the Hamilton group. Mouth of Pine Creek, Iowa. Spiru'ek Makcyi, Hull. Fig. 10. A normal individual, from which the cardinal extremities have been broken. Fig. 11. A cardinal view of the same example. Fig. 12. The interior of a brachial valve ; showing the articulating apparatus. Fig. 13. The interior of a fractjired and incomplete portion of the pedicle-valve. Fig. 14. An enlargement of the surface ; showing the elongate, lachrymiform pustules. Hamilton group. Genesee county, N. T. Spikifek TULLIUS, Hull. Fig. 18. The exterior of a pedicle-valve. Hamilton shales. Chumdaga county, iV. F. Spikifeb ligus (= Spiblfeb pennatus), Owen. Fig. 19. An adult individual ; showing normal characters. Fig. 20. A smaller indiviedicle-valve. x', MiiRciilar cavity, a'. Inner division, pedicle-valve. r. Diductor wears, a". Outer division, |>edicle-valve. j. Canlinal process. F. Delthyrium. b. Dental sockets. s'. Apical callosity. a. AnteHor adductors, d. Dental lamellae. a'. Posterior adductor?. X. Pedicle-cavity. Genus SPIKIFER, Sowerby. Page 1. Spieifer gkanulosos, Conrad. Fig^. 1. Dorsal view of a normal adult, retaining the shell. Fig. 3. The interior of a j>edicle-valve ; showing the apical callosity in the delthyrium and the character of the muscular area. Fig. 8. The interior of a brachial valve ; showing the articulating apparatus and muscular ai-ea. Fig. 4. An enlargement of the surface ; showing the papillose character of the shell. Fig. 6. The central portion of a cast of the brachial valve ; showing the striated cardinal process and the two pairs of adortionally shoi-ter and smaller than in the preceding figui-e. Fig. 10. A view of the same characters in another example. All these specimens show variations in the form of the muscular area, the size of the adductor scars as well as different degrees of devel- opment of the callosity of the delthyrium. Rg. 11. A portion of the muscular area of the pedicle-valve ; showing its surface markings and the dis- tinction between the diductor and adductor scai-s. X 2. V\g. 13. A profile of an internal cast of the pedicle-valve ; showing the filling of the rostral and muscular cavities. Fig. 13. Similar cast of another pedicle-valve with a more elevated muscular impression. Fig. 14. An enlargement of a partly exfoliated surface. Hamilton shales. Western New York. Fig. 15. An enlargement of a worn surface. The coarse punctations are not structural but probably due to some Iwring sponge. Hamilton group. Cumberland, Maryland. Spikifer mackothykis, Hall. Fig. 16. The exterior of a full-grown individual. Fig. 17. A cardinal view of an imperfect specimen ; showing the elevation of the'valves. Fig. 18. An enlargement of the surface ; showing the crenulate margins of the concentric lamellse. Comiferous limestone. Near Columbus, Ohio. Palaeonl.N.Y.Vol.IV".Ptii. Spiriferidae Generic Illustrations Plate XXE. Vk^ KP-Whittold del H Bergman lith Rg. 1. Fig. 3. Fig. 3. Figs. 4. Fig. 6. Fig. 7. Fig. 8, Fig. 9. PLATE XXIV. (Ftgare* 1-47 by B. P. Whitfield.) Lag«nd: A- DeUhyrium. l>. Dental Bocketa. D. Deltidiiim. c'. Socket-walls. Dg. Deltidial grooves. a. Anterior adductors. t. Teeth. a'. Posterior adductors. s'. Apical callosity. r. Diductoi-s. j. Cardinal process. Genus SPIRIFER, Sowerby. rage 1. Spirifer AUDACULU8, Coiuad. A small individual of normal proportiuns. 3. A brachial valve of an average example. 3. The j)edicle-valve of a i-otund specimen. 5. Doi-sal and profile views of an individual with short hinge and fewer plications. . Front view of an average adult. . The interior of the brachial valve ; showing the articulating apparatus and muscular scars. . A cardinal portion of a larger brachial valve ; showing the same structures more distinctly. . The interior of a pedicle-valve ; showing the formation of the apical callosity, and the character of the muscular area. Fig. 10. The central portion of the cardinal area of the pedicle- valve, i-etaining the remnants of the del- tidial covering. X 2. Fig. 11. A similar view of another example j showing the high development of the delthyinal callosity. Fig. 12. A part of the brachial valve ; showing the cardinal process, articulating apparatus and the char- acter of the adductor scars. X 2. Fig. 13. An enlargement of the external surface ; showing the grooves on the summits of the plications. Hamilton shales. Western New York. Spirifer angustus, Hall. Figs. 14, 15. Dorsal and ventral views of the exterior of a rather large individual. Fig. 16. A cardinal view of the same specimen. Fig. 17. An enlargement of the external surface j showing the flattened plications and incipient grooves. Spirifer audaculus, var. macronotus, Hall. Fig. 18. A cardinal view of a large individual which retains the deltidial cuvei'ing in a broken condition. Fig. 19. A cardinal view of a shallower, more extended individual. Fig. 20. A profile view of the same. Fig. 21. A view of the intei-ior of the pedicle-valve, looking into the umbonal cavity ; showing the callosity and dental plates. Fig. 22. Central jwrtion of the cardinal area; Rhowing the highly developed dellhyrial callosity. X 2. Fig. 23. A similar view of another specimen in which the deltidial covenng is retained in a bi-oken con- dition. Fig. 24. The interior of a part of the pedicle-valve ; showing the divisions of the muscular area, and the thickened dental ridges. Fig. 2.'). The interior of a similar specimen, the apex being removed to show more clearly the details of the muscular impression. Figs. 26, 27. Enlargements of the external surface ; showing characters which are often seen on the same shell. Hamilton shales. Western New York. Spiriferidae. Palaeont . N.Y.V0I .IV. Rii . Genpric Illustration!? Plate XM. PLATE XXV. (Figures 1-8 by F. B. Meek; 9-16, 22-24, 26-31 by K. P. Whitfield; 17-21, 25, 32-35 by E. Emmons.) Legend : A- Delthynum. j. Cardinal process. Dg. Deltidial groove. b. Dental sockets. b'. Apical callosity or tube. c. Socket-walls. , 8. Median septum. a. Anterior adductors. d. Dental lamella. a'. Posterior adductors. Genus CYRTINA, Davidson. Pa(?c 43. Cyrtina kostrata, Hall. Fig^. 1. A front view of a specimen somewhat below average size. Fig. 2. A cardinal view of the same; showing the tubular edge of the median septum within the delthyrium. Fig. 3. A brachial valve of a larger example. Pigs. 4, 5, 8. Views of an old shell, much thickened about the margins of the valves. Fig. 8 shows the edge of the median septum within the delthyrium. Fig. 6. The interior of a brachial valve. Fig. 7. The interior of the pedicle-valve, looking into the umbonal cavity ; showing the convergent dental lamellse, their union with the median septum, and the tubular edge of the latter. Oriskany sandstone. Albany county, N. ¥., and Oiunberland, Md. Genus SPIRIFER, Sowerby. Page I. Spirifer Macbridii, Calvin. Fig. 9. The exterior of a brachial valve. Pig. 10. The exterior of a pedicle- valve, somewhat foreshortened ; showing the faint plication in the sinus. Pig. 11. A cardinal view ; showing the elevation of the area, and the degree of development of the apical callosity. Fig. 12. The central cardinal portion of the interior of a brachial valve ; showing the articulating appara- tus and the compof^ition of the muscular area. X 2. Fig. 13. The interior of a pedicle-valve ; showing the development of the dental plates. Fig. 14. The interior of a brachial valve retaining the spiral cones ; showing their position, number of volutions and the anterior portion of the long crura. Figs. 15, 16. Etdargementa of the surface ; the former from the lateral plications, the latter from the median sinus. Hamilton group. HocJcford, lorwa. Spirifer sp., coin|)arc S. Macbuidii, Calvin. Pig8. 17, 18. Views of the exterior of a 8j)ecimen, with two low, broad plications on the median sinus, and having a somewhat diffei-ent asiiect than normal examples of (S. Macbridii. Fig. 19. An enlargement of the surface, which is covei-eil with radiating rows of elongate pustules, distinctly coarser than in ecinien ; showing a portion of the spiral cones. Fig. 4. A larger example, slightly reconstructed from a silicified interior ; showing the long crura, the disconnected jugal processes, the form of the primary lamellie and the shape and direction of the cones. Oriskany sandstone. Cumberland, Maryland. Spikifer audaculus, Connid. See Plate 24. Fig. 5. A preparation, showing the chanicter of the brachidium. (c.) Hamilton group. Canandaigua Lake, N. Y. SpiKifER IIungeufokdi, H.lll. Fig. 6. A specimen with the brachial valve i-emoved ; showing the form of the brachidium. Upper Devonian. Bockford, lotoa. Spirifer GREGARIUS, Cliipp. Pig. 7. A preparation, showing one of the spiral cones, with its jugal process and cms. X 2. (c.) Corniferous limestone. Falls of the Ohio. Spirifer mucronatus, Coin-ad. Fig. 8. A preparation, showing the form and size of the primary lamellse and the long, tapering spiral conep. (c.) Hamilton group. CaTiandaiffita Lake, iV. Y. Spirifer granulosus, Conrad. See Plate 23. Figs. 9, 10. Two views of a preparation, showing the form and direction of one of the spirals, (c.) Hamilton group. Petosky, Michigan. Figs. 11, 12. A preparation, showing the length of the crura, jugal processes and the nan-ow, small primary lamells. (c.) Hamilton group. Catiandaigiia Lake, N. T. Spirifer ligus, Owen. See Plate 22. Fig. 13. A preparation, showing the crural bases, their attachn.ent to the cmra, and the form of the spiral cones which api>ear to have been somewhat disturbed toward the apices, (c.) Hamilton group. Independence, Iowa. Spirifer subumbona, Hall. Fig. 14. A preparation, showing the lax coil of the spiral. X 4. (c.) Hamilton group. Western New York. 113 Ili^(B31IS(S2P m m £^ Palaeont.N.T.VolIV.Pt.ii'Vol.Vin. SPIRIVERmiS. ("M-iicii<- llhislr/itions. Plate XX !X E.Emmons del . Pha.Ast.lilli. FLATE XXIX— Con tinaed. Spirifeu nobilis, Banande. Vig. 16. A section along the longitudinal axis looking into one of the coils. The apparent process on the second volution is casual. Niagara group. Near Chicago, Illinois. Genus AMBOCOiLIA, Hall Page M. Amboccelia umbonata, Conrad. Fig. 15. A preparation, showing the loosely coiled spirals with but few volutions. X 6. (c.) Hamilton group. Western New York. Genus SPIRIFERINA, d'Orbigny. Page 51. Spiriferina Kentuckiensis, Shiimard. Fig. 17. A specimen whose brachidium is preserved in pyi-ite ; showing the united jugal processes which form a continuous loop. The pedicle-valve is on the lower side of the figure. Coal Measures. Vinton county, Ohio. i PLATE XXX. (ngaiw 1-17, 1», so, tS-n, so by R. P. WHITPIBLD; 18, 21, 22, 28, 29 by F. B. Hbbk.) L«genedicle-ralve ; showing the denticulations along the cardinal mar- gin, the delthyinal callosity and the form of the muscular scar. Fig. 2. Corresponding portion of a brachial valve ; showing cardinal process and dental sockets. Fig. 3. An enlargement of the cardinal area to show the denticulated cai-dinal edge of the pedicle-valve. The surface of the shell on the area is somewhat exfoliated, exposing the sories of vertical canals, each of which terminates in a denticle. The margin of the brachial valve shows a series of small sockets corresponding to the denticles. Chester limestone. Chester, lUinoit. Spibifeb ofihus, Hull. Figs. 4, 5. Brachial and profile views of a normal individual. Coal Measures. Iowa. Pig. 6. The interior of the pedicle-valve ; showing the character of the muscular impression. Fig. 7. The interior of a brachial valve. Coal Measures. Bornjardxm, Brazil. Spirifer Grimesi, Hall. Fig. 8. A cardinal view ; showing the high, relatively short area, and the convexity of the valves. Fig. 16. Doi-sal view of a nearly entire individual of normal mature size. Fig. 17. The interior of a portion of the pedicle-valve ; showing the structure of the muscular area. Fig. 18. A portion of an internal cast of the pedicle-valve ; showing the impressions of the adductor and diductor muscular scai-s. Fig. 19. Enlargement of the radiating surface stiite. Burlington limestone. Burlington, Iowa. Spirifer Newberryi, sp. nov. Rg. 9. The exterior of the brachial valve ; showing the fine plications. Kg. 10. An enlargement of the surface ; showing the fine strite. Waverly group. Ohio, Spirifer imbrex, Hall. Fig. 11. The exterior of a brachial valve. Fig. 12. An enlargement of the surface ; showing the bifurcating plications and the lamellose concentric strite. Burlington limestone. Burlington, Iowa. Spirifer sub^qualis, Hall. Figs. 18, 14. Cardinal and dorsal views of the original specimen ; showing the imbricated exterior. Warsaw limestone. Warsaw, Illinois. Spirifer Marionen.sis, Shuniiud. Fig. 15. A view of a rather small example ; showing the fasciculate plications. Choteau limestone. Pike county, Missouri. Palffiont.N.Y.Vol.IV,Ptii Spinferidae. Generic Illustrations. RP Whit*i?ii dc; jr.'iu.Asi.hth. Tig. 1. Vig. 2. Figr. 3. PLATE XXXII. (Fixaras 1-S, 7-10, 11-U by K. P. Whitfield; <-6, 11 by F. B. Hbbk.) Lagend: A- Delthyiium. a. Anterior adductors, t. Teeth. a'. Posteinor adductors, a. Deltbyrial callosity. r. Diductors. Genus SPIRIFER, Sowerby. Page 1. Spirifer lateralis, Hall. Dorsal view of a large and rather convex individual. Front or marginal view of the same specimen. An enlargement of the surface ; showing the pustulose strite on the plications. Warsaw limestone. Warsaw, Illinois. Spirifer tenuimarginatus, Hall. Figs. 4, 6. Views of an individual of normal size. Eeokuk group. Keokuk, Iowa. Spirifer rostellatus, Hall. Fig. 6. A dorsal view of the origfinal specimen. , Keokuk group. Skunk River, Iowa. Spirifer Loqani, Hall. Fig. 7. A dorsal view of the original s^iecimen ; showing the great size and general external characters of the species. Fig. 8. The interior of a portion of the pedicle-valve ; showing the articulating apparatus and the adduc- tor and diductor muaculars scars. Keokuk limestone. Near Nauvoo, Illinois. Spirifer cameratus, Morton. Fig. 9. A large individual ; showing the usual angular fasciculation of the plications. Fig. 10. Front view of the same specimen ; showing the relative size of fold and sinus. Coal Measures. Missouri. Rg. 11. An individual with broad, low fascicles composed of rounded plications. The bi'eadth of the fascicles is somewhat unusual. Coal Measures. Iowa. Fig. 12. An example with the fascicles reduced to sharp, coarse, angular, bifurcating plications. This form and that represented in 6g. 11, indicate the exti-emes of variation in exterior in this species. Fig. 13. An enlargement of a portion of the intei-nal cast of the brachial valve ; showing the narrow mus- cular impression and the anterior and posterior adductor scars. Fig. 14. An enlargement of a similar portion of a cast of the pedicle- valve ; showing the composition of the muscular area. Fig. 15. An enlargement of the surface ornamentation. The surface is marked by exti-emely fine concentric striae, which are minutely papillose. Distinct imbricating lines of growth supervene towards the anterior margin. Coal Measures. Ohio and Illinois. _ m m. ^ 's :il:l % 2F m m ^ Palaeonl.N.Y.VolIV,Pt.i Spiriferidae. Generic Illustratioi\s . Plate : ? P \Vhitfield -i"' PiillAbiltti. Fig- 1. Pig. 2. Fig. 3. Fig. 4. PLATE XXXIII. (Figares 1-23, 27 by R. P. Whitfield; 2t-2(i bj- F. B. Meek.) Legend : A. Cardinal area. f. Fissure at base of dental sockets D. Deltidium. (brachial valve), f. Foiaraen. g. Ro.stral callosity, t. Teeth. b. Dental sockets, s. Median septum. c. Crura, s'. Delthyrial callosity. sji. Sjiii-als. Dg. Margins of delthyrium (brachial a. Adductor scars, valve). r. Diductor scars. Genus SPIRIFER, Sowerby. Spiruer tkibulis, Hull. The exterior of a brachial valve of an average example ; showing the lamellose surface. The exterior of a brachial valve. The interior c.f a jiedicle-valve ; showing the character of the muscular area. A. cardinal view of conjoined valves ; showing the elevation of the area. Oriskany sandstone. Cumberland, Maryland. Spiuifer submucronatus, Hall. Fig. .5. The exterior of a normal example, retaining the deltidial covering and showing the foramen Fig. 8. An enlargement of the cai'dinal portion of the same specimen ; showing the foramen at its summit. Fig. 7. An enlargement of the surface ; showing fine radial striations on the summit of each lamella. The shading ujion this figure is such as to give an incorrect expression to the pi'ojection of the concentric lamellae. Oriskany sandstone. Cumberland, Marylaiid. Spirifer ddodenarius, Hall. Figs. 8, 9. Dorsal and cardinal views of a normal adult ; showing general form and external characters. Fig. 10 The interior of a portion of the pedicle-valve ; showing the dental lamellae, the apical callosity and the low median septum. Fig. 13. An enlargement of the external surface ; showing the fimbriated lamellae. As in tig. 7 the shading is applied in such a manner as to give an incoriect apjiearance to the lamellae. Corniferous limestone. Wtstern New York. Fig. 11. The internal cast of a pedicle-valve ; showing the outline of the muscular area. Fig. 12. The internal cast of a brachial valve. Schoharie grit. Scholiarie county, N. T. Figs. 14, 16. Two views of- a specimen doubtfully referred to this species. Locality f Sl'lRIFKK CUMBERLANDI^, Hilll. Fig. 16. An individual of normal proportions, retaining the deltidial covering and showing the concentric lamellae. Fig. 17. A partial cast of the interior of a pedicle-valve, retaining the spirals and showing the impression of the deep, muscular scars. Fig. 18. Profile of the specimen represented in fig. 16. Fig. 19. The interior of a brachial valve ; showing the articulating apparatus and low median ridge. Fig. 20. The interior of an imperfect j)eecimen ; showing the general form and proportions, and the lamellose exterior. Fig. 20. The interior of a poi-tion of the pedicle valve ; showing the median septum. Chester limestone. Buzzardfi' Rooitt, Alabama. Pig. 23. A cardinal view of an individual with a high area. Fig. 24. Oblique view of the interior of a pedicle-valve ; showing the median septum Fig. 25. The interior of a brachial valve; showing cai-dinal process, dental sockets and low median ridge. X2. Carboniferous limestone. Itaituba, Brazil. (Figs. 23-2.5 ai-e from specimens figured by Dbrby, Bulletin of the Cornell University, vol. i, pi. ii, fig. 6 i pi. iii, fig. 12 ; pi. v, fig. 4. 1874.) Spiriferina subelliptica. McChesney. Kg. 21. The interior of a portion of the pedicle-valve ; showing median septum and muscular scars. Pig. 22. The interior of a portion of the brachial valve ; showing the articulating apparatus, elevated mus- cular ridges and low median ridge. X 2. Keokuk group. New Providence, Indiana. Spiriferina spinosa, Norwood and Pratton. Figa 26, 27. Views of an entire example ; showing the exterior characters. Fig. 28. A longitudinal median section through conjoined valves ; showing the height of the median septum. Pig. 29. An enlargement of the external surface ; showing the bases of the spinules and the punctte of the shell. Chester limestone. Chenter, Illinois. Paleeom . N.Y Vol IV. Pt ii iMi Si ^ -Q :si 2 'B •J' j2 :d ^ . SiDinferid^. Genei'ir Illiistralions Plate ZXXV^ R.P UTiitfieid unl Phil.Astlith. PLATE XXXVI. (Figures 1-30 by K. P. Whitfield.) Legend (except figure 30) : 1). Deltidial plates. j. Cardinal process. A- Delthyrium. b. Dental sockets. t. Teeth. c. Socket-walls, d. Dental lamellae. a. Adductor scars. y. Rostral cavity. d. Diductor scars, s. Median septum. v. Vascular sinuses. Genus SPIRIFER, Sowerby. Page 1. Spirifer CRISPU8, Hisiuger. Fig-. 1. The exterior of a normal adult. X 3. Fig. 2. An enlargement of the nmbonal region ; showing the undefined cai-dinal area and incipient del- tidial plates. Niagara group. Bochester, N. Y. Fig. 3. The intenor of a pedicle-valve ; showing a more sharply defined area, and strong dental lamellse. X 3. Fig. 4. The interior of a brachial valve ; showing area and articulating apparatus. X 3. Niagara group. JValdron, Indiana. Fig. 5. An enlargement of a portion of the interior of the brachial valve; showing the articulating apparatus and cardinal process. Fig. 6. All enlargement of the external surface ; showing the closely crowded laniellie bearing bases of minute spinules. Niagara group. Bochester, N. Y. Spirifer bicostatus, Hall. Fig. 7. The exterior of a normal specimen ; showing the lamellose sui-face. Niagara group. Vernon Center, N. Y. Spirifer tenuistriatus, Hall. Fig. 8. View of the original specimen ; showing the radially striated plications. Lower Heledicle- valve, which retains the muscular impression. Chemung group. MeadvUle, Peimsyleania. Spirifek setigerus, Hall. Figs. 26, 27. Dorsal and profile views of a rotund, normal example; showing the incipient deltidial plates and fimbriated lamellffi. Chester limestone. Chester, Illinois. Spirifer pseudolineatus, Hall. Fig. 28. The cardinal view of a laige example. Fig. 29. A dorsal view of the same specimen ; the shell has been exfoliated on different parts of the sur- face, presenting the features shown in figure 30. Fig. 30. An enlargement of the surface ; showing the tubular charncter of the surface spinules, and, at e, the penetration of these tubes beneath the epidennal layer of the shell. The spinules ai-e represented as simple, short and blunt, but they are, on the contrary, furnished with lows of lateral branches, and are long, slender and acute. Keokuk limestone. Keokuk, lawa. PalaRom. NY.VoI IV, Pt ii. Spiriferidae. Geiierir lUii strati on. j Plate Jim ^ 11 15 d t 16 ^ R.P^A/h.itfie!Q di-. PLATE XXXVII. (Figs. 1-14, 28-31 by R. P. Whitfield; 13-15, 18, 19, 23, 24 by E. Emmons; 16, 17, 20-22, 25, 32, 33 by G B. SIMPSON.) Genus SPIRIFER, Sowerby. Page 1. Spirifek Niagakensis, Conrad. See Plate 21. Fig. 1. An enlarged view of the deltidial region of the pedicle-valve ; showing the uncompleted growth of the deltidial plates. Niagara shales. Western New York. Spikifer NOBiMS, 15;inande. Figs. 2, 3. Opposite sides of an internal cast; showing the coarse, duplicating plications, the impressions of strong dental lamellae and a low median ridge in the pedicle-valve. Niagara dolomites. Rcbcitie, Wisconsin. Spirifer mesastrialis, Hall. Fig. 4. The exterior of a brachial valve, with highly extended cardinal extremities. Fig. 5. The brachial valve of a specimen much shorter on the hinge. Both specimens show the fine stiia- tion of the median fold. Chemung group. /Southwestern New York. Spirifer Tullius, Hall. Pigs. 6, 7. Views of an average specimen. The fine radial lineation of the surface is not shown in the figures. Hamilton shales. Skaneateles, N. Y. Spikifer sculptilis. Hall. Fig. 8. Exterior of a pedicle-valve j showing the strong, distant lamellse. Hamilton group. Western New Ym-k. Spirifer consobrinus d'Oil)igiiy (=S. zic-zac. Hall). See Plate 34. Figs. 9, 10. Views of both valves of a normal example ; showing the sharp plications and the closely crowded concentric lamelliE. Hamilton group. Canandaigua Lake, N. Y. Spirifer gregarids, Clapp. Figs. 11, 12. Two views of an average specimen ; showing the short hinge, prominent umbo, and the broad, deep sinus of the pedicle-valve. Corniferous limestone. Falls of the Ohio. Spirifer Keokuk, Htill, var. ? Pigs. 13-15. Views of a silicitied shell, with sharp lateral plications, and low duplicate median plications on the fold and sinus. St. Louis group. Southern Indiana 1 Spirifer Texanus. Meek. Figs. 16, 17. Views of a rather small specimen'; showing the shiirt hinge, elongate form and highly arched umbo of the pedicle-valve. Carboniferous limestone. Qrdham comity, Texas. PLATE XXXVU— Coutinaed. Spiuifer ForbI'ISI. Norwood and Piattci). Fi^. 18. An eiilargeii view of the caiiiinal aroa of the pedicle valve, from which the surface layer has been partially exfoliated, exposing the vertical canals traversing the shell-substance. Burlington limestone. Burlington, Iowa. Spirifer lateralis. Hall. See Plate 32. Fig. 19. An enl&i-gement of the cardinal area, showing features similar to the preceding. Warsaw group. Cl\fton, Illinois. Spirifer Williamsi, sp. iiov. Figs. 20-22. Views of an enlarged example ; showing the low, coai-se and Hparpe plication of the median fold and sinus. Chemting group. Allegany county, N. Y. Spirifer Canandaiou^, sj). iiov. Figs. 23, 24. Two ^^ew8 of a somewhat distorted individual ; showing the low, rounded lateral plications and naiTow umbo. Fig. 25. An enlargement of the sui-face j showing the closely crowded concentric rows of fine granules or spine-bases. X u. Hamilton shales. Canandaigua Lake, N. T. Spirifer Hungerfordi, Hall. Figs. 26, 27. Doi'sal and profile views of a specimen with elongate outline and short hinge. Fig. 28. Anterior view of the same individual ; showing the development of the median fold and sinus. Fig. 29. A shell with an extended hinge-line and short longitudinal axis ; pi-esenting the extreme of varia- tion in this respect. Fig. 30. The central portion of the interior of a pedicle-valve ; showing the teeth, dental lamellse and mus- cular impressions. X 2. Upper Devonian. Bockford, Iowa. Spirifer plenus, Hall. See Geol. Rept. of Iowa, p. 603, pi. xiii. 1858. Fig. 32. An enlargement of a poi-lion of the inner surface of the shell ; showing the punctse. X 4. Fig. 33. A jjortion of the external surface near the anterior margin. X 6. Burlingfton limestone. Burlington, Iowa. I© Ili^(S3SIH(DIF (BID^ Palaeont.N r.Vol.rvPtii'Vol.Vin. SPIRIFERID/L ('exioric lUiislralions. Plate XXXVE. R P. Whitfield del PhilAstliih. PLATE XXXVIII. (Pigs. 1-8, U-IS, 15-19 by K. P. Whitfield; 9, 10, 14 by Q. B. Simpson ) Genus SPIKIFEK, Sowkrby. Page 1. Spirikkr MODESTUS, Hilll. Vig. 1. A silicified example ; showing the usual condition of the exteiior, and the absence of any defined cai-dinal area. X 2. Fig. 3. The intei-ior of a portion of the pedicle-valve ; showing the form of the muacalar area. Lower Helderberg group. Outnberland, Maryland. Spibifeb lineatus, Martin. Figs. 3, 4. Two views of a small specimen ; showing the form and usual condition of the surface. Fig. 7. An enlargement of the surface ; showing the spine-bases along the growth-lines. Fig. 8. An enlargement of the cardinal area of the specimen represented in fig. 4 ; showing the incipient development of the deltidial plates and limitation of the cardinal area. Coal Measures. Ivwa. Spirifer Maia, Billings. Figs. 5, 6. Two individuals, showing slight variations in length of hingfe and marginal outline. Corniferous limestone. Near Columbus, Ohio. Spirifer fimbbiatus, Conrad. See plate 36. Fig. 9. An enlargement of a portion of the exterior ; showing the long, medially grooved and divided surface-spines, with their lateral spinules. X 3. Fig. 10. A thin section of these compound spines ; showing their interior filling and the lateral spinules. X 3. Hamilton shales. Canandxiigiiri Lake, N. T. Spirifer l^vis, Hall. Fig. 11. A canlinal view of the pedicle-valve ; showing the completed deltidial covering. Fig. 12. Exterior of a )>edicle-valve ; showing faint lateral undulations. Fig. 13. An internal cast of the pedicle-valve ; showing the impression of the muscular area and ovarian markings. Portage group. Ithaca, N. T. Spirifer hirtus, White and Wiiitfield. Fig. 14. An enlargement of the surface ; showing the concentric rows of spine-bases, each of which retains the remnant of the median partition dividing it into two chambera. X 5. Kinderhook group. Illinois. Spirifer divaiucatus, Hall. FigR. 15-17. Front, dorsal and profile views of an entire individual of normal adult size ; showing the rela- tively short hinge, high area, low fold and sinus, and the even plication of the entire surface. Hamilton group. York, N. Y. Spirifer Mortonanus, Miller (=S. fastigatus, Meek and Worthen). Fig. 18. The pedicle-valve of a large individual. Fig. 19. Internal cast of a {)edicle-valve ; showing the veKical striation of the cardinal area, the impression of the muscular area and the ovavian markings. Keokuk group. Craxt^ordtvilU, Indiana. 113 m ^ (s miE © IP miB^ Palaeont.N.Y.Vol.rV.Ptii-VoI.Vin. SPIRIFERIDS. (rex\**i"i<' lllusti'Hlions. Plate XX XVIll. RPWhitfield del PM.Ast.hth. PLATE XXXIX. (Figs. 1-3 copies; 4-9, 39-41 by K. P. Whitfield; 10-14, 19-27. 29-31, 34-36, 42 by G. B. Simpson; 15-18, 28, 32, 33, 37, 38 by £. Emmons.) Genus VERNEUILIA, gen. nov. Pago 5S. Vekneuilia CHEiEOPTERYX, de Vciueuil. Figs. 1-3. Three views; showing the slig'ht asymmetry of the shell, and the trisulcate sai-face of each valve. (After PE Vkrnkdil.) Middle Devonian. Paffrath, Germany. Genus AMBOCCELIA, Hall. Page 54. Sefe Plate 29. Amboccelia umbonata, Coiiiad. Figs. 4-6. Three views of an average example ; showing the great convexity of the pedicle-valve, its me- dian groove, and the depressed-convex, marginally concave brachial valve. Fig. 7. The interior of the pedicle-valve ; showing the elevated umbo, the thickened, unsupported teeth and the partial tilling of the delthyrium. X 3. Fig. 8. The interior of the brachial valve ; showing the low cardinal pi-ocess, elevated crural plates, and the four adductor scars. X 3. Fig. 9. A pre|>aration, showing the volutions of the spiral coils. X 3. Hamilton shales. Western New York. AMBOCfELIA PLANOCONVEXA, ShlUlliird. Figs. 10-12. Views of a rather large example ; showing the general form and contour of the valves. Fig. 14. Posterioi- view of the same specimen ; showing the cardinal areas, the imperfectly developed deltidial plates and chilidiuin X 3. Coal Measures. Sjyringfield, Illvrwi». Fig. 13. A small individual. Fig. 15. Enlargement of the surface of the same specimen ; showing the short spinules. X 5. Coal Measures. Manhattan, Kansas. Amboc(elia spinosa, sp. IIOV. Fig. 16. The exterior of a bra<;hial valve. Fig. 17. An enlargement of the surface ; showing the narrow, elongate depressions which were probably the bases of superficial spines. X 6. Fig. 18. Internal cast of the same specimen ; showing the impression of the dental sockets and crural plates, and the faint adductor scars. Hamilton group. Livonia Salt Shaft, iV. Y. Genus METAPLASIA, gen. nov. Page 5«. Metaplasia py.xidata, Hall. Fig. 19. Interior of a brachial valve ; showing the articulating apparatus, adductor scars and vascular sinuses about the muscular area and over the marginal regions. X 2. Fig. 20. Posterior view of the same valve ; showing the width of the cardinal ai-ea, elevation of the cardi- nal process and socket-walls, and the linguate extension of the median sinus on the anterior margin. X 2. Fig. 21. Internal cast of the pedicle-valve ; showing the median fold, and the impressions of divergent, probably vascular sinuses extending forward from the pedicle-cavity. X 2. Fig. 22. Interior of a portion of the pedicle-valve ; showing the narrow cardinal area, thickened teeth and deep muscular scar. X 2. Oriskany sandstone. Cayuga, Ontario. Genus SPHtlFERINA, d'Orbigny. Page 51. Se« Plates 29, 'M. Spiriferina, sp. ? Fig. 23. Interior of a portion of the brachial valve ; showing the articulating apparatus and the divergent muscular ridges in the bottom of the valve. X 3. Fig. 24. A portion of the interior of the })edicle-valve ; showing a highly developed delthyrial callosity uniting the dental lamellie and supported by a median septum. X 2. Chester limestone. Caldwell county, Kentucky. Pr.ATK XXXTX-Coiitlnaed. Gknus CYRTINA, Davioson. rage 43. 8«e Plates 25, 28. Cyktina, sp. ? Fi(f. 25. An enlarg«iueiit of the surface ; showing the bases of concentric rows of spinules. X 4. Fig. 26. Caiilinal view of an internal cast of the pedicle- valve, bi-oken so as to show the convergent dental plates uniting with the median septum, and the slight projection of the edge of the latter within the spondyliuni thus formed. Fig. 27. The same B))ccimen viewed from above j showing the length of the median septum. Fig. 28. An enlargement of a portion of the interior of the pedicle-valve ; showing the convergence of the dental plates, and the pi-ojection of the median sejitnm beyond their union. X 3. Chert-beds of the Burlington limestone. Burlington, finoa. GENU8 SYRINGOTHYRIS, VVinchell. Pago 47. See Plates 25, 26, 27. Sykingothyris Missouri, sp. iiov. Figs. 29-31. Three views of the typical sjiecimen ; showing its small size, elevated pedicle-valve, broadly rounded cardinal margins, and coarse lateral plications. Internally this shell has the syringo- thyi-oid tubiferous |)late, and the shell-substance is highly punctate. Cboteau limestone. Pike county, Missouri. Genus CYRTIA, Dalman. Page 40. See Plates 21, 25, 26, 28. Cyrtia exporrecta, \Vtihlenl)eig, v:ii-. arrecta, Hall iiiul Whitfield. See Plate 28. Fig. 32. View of the umbonal cavity of the conjoined valves ; showing the foramen, the strong dental plates, and the articulating apparatus. X 2. Niagara group. Louisville, Kentucky. Cyrtia radians, sp. iiov. Pig. 33. Internal cast of a large specimen ; showing the general contour of the pedicle-valve, the impres- sion of its dental plates and low median septum. Niagara group. Milwaukee, WiscoTisin. Cyrtia simplex, Philliiw. Pigs. 34, 35. Cardinal and profile views of an entire inout the anterior margins of the valve. Chemung gi"onp. Meadville, Pennxylvania. Genus SPIRIFER, Sowerby. I'atre I. Spirifer acuminatus, Coiiiad. Figs. 39, 40. Profile and cardinal views of a normal example ; showing the sharply elevated median fold and the duplicate plications. Comiferous limestone. Sandusky, Ohio. Pig. 41. Internal cast of a large pedicle-valve ; showing the size and composition of the muscular area. Hamilton shales. Haxtem New York. Fig. 42. Internal cast of the central cardinal portion of the brachial valve ; showing the impi'CBsion of the deejily striated cavity i-epresenting the cardinal process, the position of the cardinal area, dental sockets and socket-walls. X 4. Comiferous limestone. Hanover, Indiana. Palaeont. N.Y.Vol.IV.Pt ii= Vol.vm. J3 la^CSSIIIOIF (DE)^ SPIHIVERmit Generic Uhirttratioiis. Plate XXXIX. Q.B.SimpBon del PhilAstlith. PLATE XL. (Figures 1-3, 6, 7, 10, 12-21, 23-31 by E. EuMONS; 4, 5, 22 by R. P. Whitfield; 8, 9, U by G. B. Simpson.) Legend : dl. Dental lamelliE. x. Stem of loop. hp. Hinge-plate. r. Diductor scars, vs. Median cleft of hinge-plate. a. Antei-ioi- adductors. OS. Crural plates. a'. Postei^ior adductors. 8. Median septum. v. Vascular sinuses. 1. Loop. Genus WHITFIELDELLA, gen. nov. Page 68. WHITHELDELLA INTERMEDIA, Hilll. Fig. 1. The interior of a pedicle-valve ; showing the unclosed delthyrium, teeth and convergent dental lamella. X 2. Fig. 2. Cardinal portion of the brachial valve ; showing the median division of the hinge-p]ate into two triangular processes. X 4. Clinton group. Hamilton, Ontario. WniTFIELDELLA NAVIFORMIS, Hall. Fig. 3. The cardinal portion of a brachial valve ; showing the structure of the hinge-plate, which is prima- rily divided medially, the median cleft being partially filled by an erect lobe. X 3. Clinton group. Wegtem New York. WHITFIELDELLA NITIDA, Hull. Fig. 4. The cardinal portion of a pedicle-valve ; showing the teeth, and the foramen almost enclosed by the substance of the shell. X 3. Fig. 5. The cardinal portion of a brachial valve ; showing the medially divided hinge-plate, the faint median septum and the elongate dental sockets. X 3. Fig. 6. A preparation of the spirals and loop in a specimen in which the entire brachidium has been detached from the crura and revolved through an arc of 180°, entirely reversing its normal position. Fig. 7. A profile of the same specimen. In both of these figures the horizontal stem of the loop as lepre- sented is much too long, and in figure 7, the dotted line from the letter x should terminate at this stem and not on the supporting matrix, (c.) FigB. 8, 9. Two views of a large and transvei-se example ; the usual form occurring in this locality. Niagara group. Wa/dron, Indiana. Fig. 10. An internal cast of conjoined valves ; showing the position of the dental plates [in the jiedicle- valve, the impression of the divided hinge-i)late, muscular seal's and vascular sinuses in the brachial valve. X 2. Niagai-a dolomites. Milwaukee, Wisconsin. Fig. 1L[^ Dorsal view of an elongate shell, having the greatest width anteriorly. Niagara group. Waldron, Indiana. Figs. 12, 13. Dorsal and anterior marginal views of a shell ; showing the prevailing foi-m of the species at this locality. X 2. Niagara group. Louisville, Kentucky. WHITFIELDELLA DIDYMA, Dallliail. Figs. 14, 15. Two views of an average specimen; showing the usual form of the shell, and the nai-row, elevated umbo of the pedicle-valve. Wenlock limestone. Island of Gotland. PLATE XL— Continued. Whitfieldella oylindrica, Hall. Kig8. 16, 17. Ventral and pi-ofile views of a large individual. Figr. 18. A preparation of the brachidium ; showing the mode of attachment of the spirals and the form of the loop, (c.) Fig. 19. A similar preparation ; showing the form of the spirals when exposed by the removal of the brachial valve, (c ) Fig. 20. The internal cast of a pedicle-valve j showing the de<>p impression of the diiluctor scai-s. Fig, 21. The internal cast of a t>rachial valve ; showin!.' the impressions of the crural plates and short median septum. The anterior portions of this shell are concealed by the matrix. Fig. 22. The exterior of a normal example ; showing the high shouldered umbones and inconspicuous beak. Niagara group. Hillsboro, Ohio. Genus HYATTELLA, gen. nov. Page 61. Hyattella conoesta, Coiuad. Fig. 23. The internal cast of a pedicle-valve ; showing the impressions of the pedicle-cavity and the muscu- lar area. X 2. Fig. 24. A cardinal view of the same sjiecimen ; showing the impression of the dental lamellae and of the divided hinge-plate. X 2. Clinton group. ReyndU's Basin, N. T. Fig. 25. Exterior of a i-ather large specimen : showing the trilobation of the exterior which is frequently more developed than in this instance ; also the tine concentric lineation of the surface. X 2. Clinton group. Lockport, N. Y Fig. 26. A restoration of a brachidium, made from transverse sections of silicitied specimens, (c ) Clinton group. ReynaWa Basin, N. Y. Fig. 27. The cardinal portion of a bi-achial valve ; showing the sti-ucture of the hinge-plate, its narrow median division, and the bases of the crura. X 5. Fig. 28. The same specimen viewed in profile from the front ; showing the conspicuous elevation of the lateral divisions. X 5* Clinton group. Lockport, N. Y. Hyattella Junia, Billings. Figs. 29-31. Three views of a normal individual ; showing the strong lobation of the surface and the tine concentric lineation. X 2. Middle Silurian. Cape East, Anticosti. Palaeont. N Y.Vol rV.Pt.ii'Vol.vni. IB II3.^(S31IH®IP CDIDi;^o MERISTIDJL GnanMiric Illustrations Plate XL. S.Emmons del Phil.AsiUth. PLATE XLI. (Figures 1 by C. E. Beecher; 2, 8, 29, 30 by G. U. Simpson; 4, 7, s, 11-20, 22-28, 31, 32 by E. EMMONS; 5, (i by R. P. Whit- field; 9, 10, 21 by J. M. Clarke.) Legend : r. Diductoi- scars. p. Cast of the pedicle-cavity. a. Adductor scars. Genus MERISTINA, Hall. Page 65. Meristina Maria, Hiill. Fig. 1. Tbe youngest shell observed ; showing the foramen which is concealed in the adult condition, and the lenticular valves without fold or sinus. X 5. Figs. 2, 3. Two views of an average adnlt individual ; showing the gibbosity of the valves, the close in- curvature of the beaks and the development of the fold and sinus. Fig. 5. The cardinal portion of the brachial valve; showing the median cleft in the hinge-plate, forming an elongate cavity supported by a low median septum. X 2. Fig. 6. The cardinal portion of a mature pedicle- val ve ; showing the open delthyrium from which the deltidial plates have been resorbed, and the thick teeth supported by dental plates. Niagara group. Waldron, Indiana. Fig. 7. The brachidium, viewed from the brachial valve and natui'ally retained by incrustation ; show- ing the form of the cones and the bifurcated loop. Niagara dolomites. BridgejKirt, Illinois. Fig; 8. A preparation of the brachidium, showing its lelations to the valves, and the great size of the primary lamellse. (c.) Fig. 9. A preparation, showing the condition of the brachidium at a very early stage of growth. The primary lamellse ai-e very long and much stronger than the othei'S ; the spii'al cones much depressed and its volutions few and lax. The stem of the loop appears to be simple at its extremity, but this may be due to imperfect I etention. X 5. (c.) Fig. 10. A larger but still immature shell which has suffered an injury to the peiipheral growth of the valves on one side. This obstruction has produced a deformation of the spiral cone on that side, which has conformed itself to the ii'regularly contiacteecjmen ; showing the relatively slight convexity of the valves. X 2. Middle Devonian. E\fel, Oermany. m m^ffiiuHffiiF (BiE^ Pal8Bont.N.T.Vol.IYPt-ii = Vol.Vm. MERISTIUJL rVeiieric Ilhistrations. Plate XL 1. E Emmons del . PhilAstUth. PLATE XLII. (Figures 1-6, ll-«, 2S, 27-29 by E. EHHONs; 7-10, 22-24, 26, 30-32 by R. P. Whitfield.) Legend : pi. " Shoe-lifter." b. Dental sockets. t. Teeth. c. Crura, dl. Dental lamellae. a. Adductor scare. hp. Hinge-plate. r. Diductor scare, s. Septum of brachial valve. Gknus MERISTA, Suess. Page 70. Merista Tennesseensis, sp. nov. Figs. 1, 2. Two views of the exterior of a somewhat elongate example. Fig. 3. The interior of a pedicle-valve of a broader form ; showing the " shoe-lifter" process. Fig. 4. The interior of a brachial valve of the same specimen ; showing the divided hinge-plate and the median septum. Fig. 5. The exterior of the pedicle-valve j showing the cavity left by the removal of the " shoe-lifter." Fig. 6. A broad individual viewed from the brachial valve. Lower Helderberg group. Perry county, Tennessee. Merista tyfa, Hall. Fig. 7. The interior of a pedicle-valve somewhat incomplete about the margins ; showing the great width of the "shoe-lifter," and the extension of the dental plates upon its surface. Figs. 8, 10. Two views of the exterior of a normal adult specimen. Fig. 9. Interior of a pedicle-valve in which the "shoe-lifter" is highly arched and the dental lamellffi con- spicuously thickened. Fig. 11. A pedicle-valve having a very broad and low "shoe-lifter," and short, scarcely divergent dental plates. Fig. 12. An imperfect pedicle-valve with sharply angled and highly elevated " shoe-lifter," and prominent dental plates. Lower Helderberg group. Cumberland, Maryland. Subgenus DICAMARA, s.-gen. nov. Page 73. DiCAMARA SCALPRUM, F. RoGiiier. Kg. 13. A profile of a specimen cut to show the form of one of the spiral cones. Fig. 14. View of the same preparation from the pedicle-valve ; showing the spirals and the cavity left by the i-emoval of the " shoe-lifter." Middle Devonian. Hartz Mountains (?), Germany. Fig. 15. The interior of a brachial valve j showing the " shoe-lifter," and the dividing median septum. Drawn from a gutta-percha impression which retains on the posterior margin a portion of the pedicle-valve. Fig. 16. A view of a specimen which shows the cavity left by the removal of the " shoe-lifter " of the bra- chial valve, the median septum remaining in place. The apical portion of the cavity of the " shoe-lifter " of the pedicle-valve is also shown. Middle Devonian. Pelm, Germany. PLATE XLn— ContinDert. Genus CHARIONELLA, Billings. Psgo 78. ChAKIONELLA 8CITDLA, Billiiigs. Rg'. 17. Dorsal view of a specimen from whicli a portion of the shell has been removed exposing the mus- cular impressions of the bi-achial valve and the median thickening of the hinge. Kg. 18. An internal cast of the pedicle-valve ; showing the impression of the muscular area and traces of the radiating lines on the inner laminse of the shell. 'Fig. 19. The cardinal portion of the brachial valve. The hinge-plate in this genus takes the form of a concave thickening adherent to the bottom of the valve. That portion of it which forms the socket-walls lies close against the margins of the valves making .very narrow dental sockets. The crura arise from the inner extremities of these walls. Comiferoas limestone. Cayuga, Ontario. Chauionella Hyale, Billings. Figs. 20, 21. Two views of an internal cast, having a hinge-structure similar to that in the preceding species. Guelph limestone. Cfuelph, Ontario. Genus PENTAGONIA, Cozzens. Page 80. Pentagonia unisulcata, Conrad. Fig. 22. The exterior of a pedicle-valve ; showing the broad, angular median sinus. Fig. 28. A cardinal view of the same specimen ; showing the median sinus on each valve and the single pair of cardinal folds on the brachial valve. Kg. 24. Anterior marginal view of the same specimen ; showing the elevation of the median fold of the brachial valve. Comiferous limestone. Western New York. Pigs. 26, 2<5. Profile and cardinal views of a specimen which has no sinus on the fold of the bi achial valve. Hamilton gi-oup. Centerfield, N. T. Fig. 27. The hinge-jilate as viewed from the front ; showing the erect position of the crura. Fig. 28. The same specimen viewed from above ; showing the deep central excavation of the hinge-plate, the form of the socket-walls and the position of the crura. X 3. Fig. 29. A preparation, showing the form of one of the spiral cones and of a portion of the loop. It is probable that the latter feature is incomplete, (c.) Hamilton group. Western New York. Fig. 80. The interior of a brachial valve ; showing articulating processes, muscular impression and short, low median septum. Comiferous limestone. Falls of the Ohio. Kg. 31. Cardinal view of a shelHwith two pairs of folds on the posterior margin of the brachial valve. This is the form which has been termed var. biplicata. Hamilton group. Darien, N. Y. Kg. 83. The interior of an imperfect pedicle-valve ; showing the articulating apparatus and muscular im- pressions. Comiferous limestone. Fails of the Ohio, IB 33.^CBSIH®IF ©ID^ PalsBont.N.r.Vol.IVPt.ii-VQl.vni. NfElilSTID.V. ("'(•lu^ric llhistralioiis Plate XL II. £ Emmons del. Phii.Ast.luh. PLATE XLIII. (Figures 1-13 by P. B. Meek; 14, 15, 18-30 by R. P. Whitfield; 16, 17 by E. Emmons.) Genus MERISTELLA, Hall. Page 73. Meeistella arcuata, Hall. See Plate 44. Figs. 1, 2. Two views of a noi'mal shell ; showing form and contour. Lower Helderberg group (shaly limestone). The Helderbergs, N. Y. Meristella l^vis, Hall. See Plate 44. Figs. 3-6. Dorsal, profile, cardinal and front views of an adult shell. Lower Helderberg group (shaly limestone). Albany county, N. Y. Meristella bella, Hall. See Plate 44. Figs. 7-9. Ventral, front and dorsal views of a normal individual ; showing the median sinus on both valves. Lower Helderberg group. Schoharie, N. Y. Meristella peinceps, Hall. Figs. 10, 11. Profile and front views of an example of extremely large size, with an unusual development of the shallow median sinus and linguiform extension in front. Figs. 12, 13. Dorsal and ventral views, presenting the usual characters of an adult specimen. Lower Helderberg group. Schoharie, N. Y. Meristella subquadrata, Hall. Figs. 14, 15. Dorsal and profile views of a typical specimen. Lower Helderberg group. Schoharie, N. Y. Meristella Walcotti, sp. nov. See Plate 44. Figs. 16, 17. Dorsal and profile views of a rotund and rather elongate example. Oriskany sandstone. Cayuga, Ontario. Meristella nasuta, Con rati. See Plate 44. Fig. 18. Ventral view of a shell of median size. Corniferous limestone. Erie county, N. Y. Figs. 19, 20. Dorsal and profile views of an unusually large, strongly nasute example ; showing in profile the plano-convex contour of the shell. This is the form originally described as Meristella Elissa, Hall. Schoharie grit. Albany county, N. Y. Meristella Doris, Hall. Figs. 21, 22. Dorsal and profile views of a normal shell ; showing the deltidial plates and fine radial surface striae. Corniferous limestone. Williainsville, N. Y. PLATE XLUI— Ck>nUnueil. Meeistella Haskinsi, Hiill. See Plate 44. Figs. 23, 24. Dorsal and profile views of the usual form of the species. Hamilton shales. Moscow, N. Y. Mekistella Bakkisi, Hall. See Plate 44. Figs. 25, 26. Ventral and dorsal \'iew8 of different shells, giving the external characters. Limestone of the Marcellus shales. Stafford, N. ¥. Mekistella rostkata, Hall. Figs. 27, 28. Dorsal and profile views, showing the usual form and size of the species. TuUy limestone. Ovid, N. Y. Meeistella Meta, Hall. Figs. 29, 30. Dorsal and ventral views of an adult specimen. Hamilton group. Delphi, N. Y. Pal aeont . N. Y. Vol . lY Pt.ii= Vol vm. m m jS^ (s m 11 ® IP © m j^ MZHISTID& Generic lilTistrations. Plate XL III. RP.Whitfield del. Phil.Astlith. PLATE XLV. \ (Figures 1-3, 0-12, 16, 18-24, 26-28, by R. P. Whitfield; 4, 6, 13-16, 25, 29, 30 by E. Emmons; 17 by G. B. SIMPSON.) Genus ATHYRIS, McCoy. Page 83. Athyris vittata, Hiill. Figs. 1-3. Dorsal, profile and anteiior marginal views of a normal individual j showing its comparatively short transverse diameter and the development of the median fold and sinus. Fig. 4. The hinge-plate as viewed from above ; showing the trilobation of the anterior mai-gin, the deep depression of the median portion, the coalescence of the lateral portions with the socket-walls, and the large, unobstructed visceral foramen. The lateral lobes are the bases of the crura and are incorrectly represented as entire at their outer extremities. X 3. (c.) Fig. 5. The interior of the cardinal portion of conjoined valves, the brachial valve being above. This view shows the elevation of the anteiior face of the hinge-plate, the internal opening of the visceral foramen, the extension of the median lobe of the plate, the thickened crural plates, the crura attached to the crural lobes and their mode of union with the primary lamellae of which a portion is shown. X 3. (c.) Hamilton group. Falls of the Ohio. Athyris Cora, Hull. Figs. 6-10. Dorsal, profile, cardinal, ventral and frontal views of the original specimen, which is somewhat exfoliated about the umbones ; showing the sublenticular contour and the low median sinus on each valve. Hamilton gi-oup. Delphi, N. T. Athyris spiriferoides, Eaton. Fig. 11. Dorsal view of a large and senile individual, having the surface lamells highly developed and the median fold conspicuously elevated at the anterior margin. Fig. 12. The interior of a pedicle-valve ; showing the mature condition of the foramen without deltidial plates, the pedicle-, adductor and diductor scars. Hamilton group. Soft sluiles of Western New York. Fig. 13. A preparation of the brachidium, one of the spiral cones being removed to expose the structure of the loop. This figure shows the depressed ventral surface of the cones, the mode of attach- ment of the crura to the primary lamellse, the anterior position of the loop, its broad lateral branches and saddle, the long stem, and the width and extent of the accessory lamellae. X2. (c.) Hamilton group. Alpena, Michigan. Fig. 14. An enlargement of the hinge-plate ; showing its subquadrate-triangular outline, the oblique aper- ture of the visceral foramen, the thickening of the crural bases and the elevation of their posterior extension in the form of socket-walls ; also the dental sockets and the slight submai-- ginal thickening outside of them. X 3. Fig. 15. An anterior view of the same specimen ; showing the stout crural plates resting upon the bottom of the valve, and forming the inner wall and base of the dental sockets. In the background are seen the posterior elevation of the socket-walls, the visceral foi'amen and the beak. X 3. Hamilton group. Clarke county, Indiana. Fig. 16. A dorsal view of conjoined valves of a small individual on which the surface lamellae are few and distant. Hamilton group. Western New York. Fig. 17. The inteiior of a brachial valve ; showing the structure of the articulating apparatus and the elongate scar of the adductor muscles. Hamilton group. Falls of the Ohio. PLATE XLV— Continued. Figs. 18, 19. Dorsal and cardinal views of a narrow and rather rotund individual. Fig. 19 shows the mar- ginal inflexion on the cardinal slojies of (he pedicle-valve. Fig. 20. Frontal view of a shell, showing about the minimum development of the median fold and sinus. Fig. 21. Frontal view of a large example in which the development of median fold and sinus has virtually attained its maximum. Hamilton group. Varimis localities in the soft shales of Western New York. Rg. 22. A doiTsal view of an internal cast of conjoined valves, showing the impression of the hinge-plate, the tilling of the visceral foramen, the muscular scars and vascular markings, and also the cast of the rostral cavity of the pedicle-valve. Hamilton group. Hardy county, Virginia. Rg. 23. A'ventral view of a preparation of the brachidium ; showing the form of the 8{>iral8, the crura and their attachment to the primary lamellae, and the accessory lamellse. Fig. 34. An intei-nal cast of the pedicle-valve, slightly broken at the umbo ; showing the adductor and diductor impressions, and the vascular sinuses. Rg. 25. The exterior of a transverse, coarsely lamellose individual. Hamilton group. Various localities in the s?iales of Western New York. Athykis Angelica, Hall. Fig. 26. The exterior of a brachial valve. Fig. 27. The exterior of a pedicle-valve. These figures show the fine, crowded concentric striae extending from umbones to margins. Fig. 28. An internal cast of a pedicle-valve ; showing the filling of the deep pedicle-cavity, and the indis- tinct scar of the diductors. Chemung group. Btlmont, N. Y. Fig. 29. Anterior view of the hinge-plate ; showing the straight anterior edge, the crural plates, visceral foramen, and the elevation of the posterior portion of the surface. X 3. Fig. 30. A profile view of an old and giblx)us shell, with a few strong growth-lines. Chemung group. Belfast, N. Y. Athyndae. Palaeont.N.T.Vol.IV.Pt-ii'Vol.Vm. <.'*»! KM" ic illusll-jttlOllS Plate XUr RP. Whitfield del Pliii.Ast.lith. PLATE XL VI. (Figures 1-5 by E. P. Whitfield; 6, 10, 16, K-at by G. B. Simpson; 7-9, 11-21, 25-28 by E. Emmons.) Legend : p. Filling; of pedicle-cavity. l a. Anterior adductors. t. Teeth. a'. Posterior adductora. d. Dental lamellae. vc. Cast of viscei-al foramen. C8. Cardinal margin. " hp. Cast of hinge-plate. r. Diductor scare. Genus ATHYRIS, McCoy. Page 83. See Plate 45. Athykis polita, Hall. Fig. 1. A venti-al view of an internal cast; showing the filling of the rostral cavity and the muscular impressions. Fig. 2. Doreal view of the same specimen. Figs. 3-5. Profile, doi-sal and ventral views of a specimen retaining the external surface. Chemung group. Steuben county, JV. Y. This species has more the contour of shells which have been placed under the subgenus Sbmi- vvjji, than of the true Athyris. Should its surface prove to be devoid of free lamellse, it would naturally fall into that group. Athybis DENSA, sp. IIOV. Fig. 6. The interior of a small but thickened and entire pedicle-valve ; showing the broad cardinal sur- faces, the deep pedicle-cavity and the relatively large muscular impressions which extend almost to the anterior margin of the valve. St. Louis gi-oup. Colesburgh, Kentucky. Fig. 7. The interior of a larger pedicle-valve ; showing the thickening in the umbonal region and the division of the muscular area by a prominent ridge. Fig. 8. The interior of a pedicle-valve with broader cardinal margins than the preceding specimens, and retaining the median ridge, but with the muscular area obscure. St. Louis group. WasMngton county, Indiana. Figs. 9, 10. Profile and dorsal views of conjoined valves ; showing the contour of the shell, the foramen and broad cardinal slopes of the pedicle-valve, the median elevation and low marginal sulcus of the brachial valve. St. Louis group. Colesburgh, Kentucky. Fig. 11. The interior of a pedicle- valve, with a relatively small muscular area, and a linguate extension of the anterior margin which is much foreshortened in the figure. St. Louis group. Lanesville, Indiana. Fig. 12. The interior of a pedicle-valve ; showing in fuller detail the structural features. St. Louis group. Colesburgh, Kentucky. Athyris Hannibalensis. Swallow. Fig. 13. A dorsal view of the exterior of conjoined valves ; showing the highly lamellose surface. Fig. 14. The exterior of a i>edicle-valve ; showing the bases of the free lamellae, and the low median sinus. Fig. 15. The interior of a pedicle-valve ; showing the character of the muscular area. Choteau limestone. Louisiana, Missouri. Athyris lamellosa, L6 veil 16. Fig. 16. The ventral side of an internal cast of conjoined valves ; showing the striated scar of the pedicle- muscle, the cordate and sharply defined adductor scars, and the faintly outlined diductors. Near the anterior margin is a portion of one of the broad concentric lamellae. Fig. 17. The opposite side of the same specimen ; showing the peculiar form and division of the adductor acars, and a portion of one of the concentrically striated free lamellae. Waverly group. SdotoviUe, Ohio. PUA^TE XLVI— CohUnaod. Fly. 18. The exterior of a jkhUcIc- valve ; showing the normal marginal outline of the species. Fig. 18. The exterior of a large l)iiichiAl valve with few and ilistaut lamella; and unusually extended hinge-line. The firet of these lamella; bears a serrated margin, while the rest are regular. The anterior and lateral margins of the valve are concealed by the great expansion of the submarginal lamella. Keokuk group. CrawfordsvUU, Indiatia. Fif. 90. The central cardinal |>ortion of an internal cast of conjoined valves, enlarged ; showing the posi- tion of the teelh, dental plates and hinge-plate, the filling of the pedicle- cavity and visceral foramen, the latter being traversed for its entire length by a median groove, representing a faint median ridge ujwn the brachial valve, extending fi-om the ajiex across the muscular area. X 3. Waverly group. SciotovUh, Ohio. Athvris INCRASSATA, Hilll. Fig. 21. The exterior of a somewhat weathered pedicle-valve. Burlington limestone. Burlingtmi, Iowa. Genus SPIRIFER, Sowerby. Page 1. Fig. 22. This figure is an enlarged repre8enta.tion of an internal cast of a small pedicle-valve belonging to a species of Spirifbr similar to S. psmidolineatus. Hall. This fossil occurs in the soft shales of the Waverly group, and its generic charactera are usually obscured. Its relation to Spiriper is indicated by the long, thin denial lamellse, low median septum, and fine surface spines which are ]>lainly double-bari-elled at the base. Additional specimens obtained since this plate was engraved show that these spines bear series of short lateral branches. Waverly grroup. Richfield, Ohio. Genus ATHYRIS, McCor. Pago 83. Subgenus CLIOTHYRIS, King. Cliothyris Rotsii, Levcille. Fig. 28. Dorsal view of conjoined valves ; showing the concentric rows of flat spines. X 2. Keokuk group. Keokuk, lovoa. Fig. 24. An enlargement of a portion of the surface. Chester limestone. Jackson arunty, Kentucky. Cliothyris hirsuta, Hall. Fig. 25. Dorsal view of an average specimen denuded of its spines. X 2. Fig. 26. A larger specimen with portions of the rows of flat spines adhering. X 2. Fig. 27. View of the hinge-plate ; showing the crescentiforra wall made by the crural lobes, and the thick central lobe of the plate. X B. Fig. 2S, The same B|>ecimen viewed from in fi-ont ; showing the elevation of the hinge-plate, the ci-ural baaes and the minute visceral foi-amen which is usually closed in its upward extension. X 5. St. Louis limestone. BUxnnington, Indiana. 113 ISi^ceSTSdllF (SIEJv^ Palaeont. NT.VoMYPt ii'Vol.Vm. ATHYHias. (''(•m.-1-ic lU\ii>fcrations, Plate XLVI £ Emmons del. Phii:Astlith. PLATE XLVII. (Figs. 1-6, 12, 16-20, 83-34 by E. EMMONS; 7-11, IS-IS, 21 by G. B. SIMPSON.) Legend: p. Pedicle-cavity. r. Diductors. vc. Visceral canal. v. Vascular sinuses. a. Ailriuctors. ub. Umbonal blades of primary lamellse. a'. Anterior adductora. al. Accessoi-y lamellse. Genus ATHYRIS, McCoy. Page 8f. Subgenus SEMINULA, McCoy. Seminula ROGEllSI, sp. uov. Fig. 1. A dorsal view of an internal cast of conjoined valves. Fig. 2. A ventral view of a similar specimen ; showing the cast of the pedicle-cavity and muscular scars. Fig. 3. A cardinal view of the specimen represented in figure 2 ; showing, in addition to the features men- tioned, the casts of the visceral foramen and hinge-plate. Fig. 4. A profile of the specimen represented in figure 1. Pendleton sandstone. Pendleton, Indiana. Seminula trinuclea, Hall. Pig. 5. A dorsal view of conjoined valves ; showing the contour of the species. X 2. Fig. 6. A frontal view of the same specimen. X 2. St. Louis limestone. Bloomington, Indiana. Fig. 10. A ventral view of an internal cast of conjoined valves ; showing the filling of the pedicle-cavity and the small muscular scar. X li. Fig. 11. A dorsal view of the same specimen; showing the filling of the pedicle-cavity and the visceral foramen, the cavity of the dental and hinge-plates, and the faint muscular area. X I^. St. Louis group. Spergen Hill, Indiana,. Fig. 12. A doi-sal view of a more strongly trilobed internal cast ; showing with greater distinctness the character of the muscular area. St. Louis gi'oup. Harrison county, Indiana. Fig. 13. A view of the hinge-plate ; showing its subquadrate outline and the prolongation of the crural lobes. X 5. Fig. 14. The same specimen viewed from the beak, the latter being removed to show the elevation of the posterior extension of the plate, and exposing the visceral foramen. X 5. St. Louis group. Spergen Hill, Indiana, Seminula subquadkata, Hall. Fig. 7. A dorsal view of conjoined valves, showing the sharp and distant concentric lines. Chester limestone. Crittenden county, Kentucky. Fig. 8. A dorsal view of a somewhat more orbicular form. Fig. 9. A profile of the same specimen. This shell is associated with typical forms of aS. trinuclea and at this locality passage forms between these two extremes of expression are readily found. At other localities this form may prevail to the exclusion of the others. St. Louis limestone. 8pergen Hill, Indiana. Fig. 15. The interior of a brachial valve of a more distinctly trilobed individual ; showing the adductor scars and the hinge-plate which is slightly broken on the anterior mai-gin. Fig. 16. An anterior view of the hinge plate ; showing the visceral foramen and the elevation of the crural plates and lobes. X 3. St. Louis limestone. Pella, lovja. PLATK XLVII— Coulliiued. Seminula subtilita, Hall. Vig. 17. A view of the hing-u-plate ; showing: its excavate upper face, subquadrate outline, striated pos- terior extensions and minute visceral foramen. X 6. (t) Chester limestone. Caldwell county, Kentucky. Fig. 18. The hinge-plate of another specimen ; showing some differences in outline and surface. The position of the visceral foramen ia occupied by a minute lobe. X 6. Coal Measures. Manhattan, Kansas. Vig. 19. A dorsal view of an orbicular and faintly lobed form. Coal Measures. Coppers Creek, Iowa. Vig. 90. A large specimen, very bread in the |)allial region and strongly lobed on the anterior margin. (f) Chester limestone. Che.<eciineii. Lower HeUlei-lHTg' jfi-oiip. Square Lake, Maine. Genus RIIYNCHOSPIRA, Hall. Page 108. RhYNCHOSPIRA (?) 8UBOLOBOSA, Hall. B1(r- 23. A dorsal view of an iiiteinai cast of tUe uoiijoiiied valves; (ihowiii(^ the form of the shell and the impression of the hinge-plate. This ia the original specimen and its generic relations are net fully determined. Schoharie grit. Schoharie, N. T. Genus TREMATKOSPIRA. Hall Pai?c 124 Trematrosi'ira oibbosa, Hall. Figs. 23-26. Dorsal, ventral, carditml and frontal views of a large, old and thickened shell ; showing the coarse and shai-ji plication and jii-esenting the usual form of the species. Vig. 27. A smaller example with the median fold and xiniis less distinctly developed. Hamilton givup. Yates county, N. T. Genus PARAZYGA, gen. nov. Page 127. Parazyga hirsuta, Hall. Pigs. 28-32. Dorsal, ventral, cardinal, frontal ami profile views of a normal individual ; showing the form, contour and tine plication of the valves. The .surface of the shell was covered with short and exceedingly fine hair-like spinules which ai-e i-etained only under the most. favorable preserva- tion This is one of the original specimens of the species. Fig'. 83. A prepai-ation, showing, by removal of the brachial valve, the form of the spiral cones and their attachment to the crura. Fig. 34. The interior of a pedicle-valve ; showing the character of the muscular area and the concave del- tidial plates. Fig. 35. The interior of a brachial valve ; showing hinge-plate and muscular impressions. Fig. 36. A pi-eparation of the bi-aihidium, the i>ed!cle-valve and the upper portion of the spiral cones being removed J showing the mode of attachment of the crura and primary lumellse and the foi-m of the loop. The hinge-plate is not correctly represented. X 2. (c.) Fig. 37. The hinge-plate enlarged ; showing its bipartite form and the broad dental sockets. X 3. Fig. 88. The inferior of the i-oslral region of the pedicle-valve from which the marginal poi-tion has been removed, exi>osing the short delthyiial or pedicle tube, and remnants of the teeth and dental plates. X 3. Fig. 39. The cardinal i)ortion of the pedicle-valve ; showing the \f\\. similar m form to T. vmltistriata. Imt diffei-ing from that species in the reguUr, t-qual, rounded and unliifurcated surface pliialions. Those in T. iniUti- Ktriata are not satisfactorily represented in figures 9 and 10, but are sharper and often strongly fasciculate. Lower Helderberg group. Cumberland, Maryland. m m ^ (s mn m s> ^ m £^ Palaeont.N.Y.Vol.JV.Pt.ii-Vol.Vin. THEMATOSHIHIDA (»oTi<'i"ir llhistrations. Plate XLIX. RP 'A'ni'f-.eld d-ii Phil.Ast.lith. PLATE L. igures 1-5 copies; 6 8, li-U. 26-31, 4I-«8 51, 5-3 by E. Emmons; 7, S-11, 16, 17, 20. 22, 24, 32-35 by G B SIMPSON- 15, 18, 19 by J M. Clakke; 21 by F. B. Meek; 23, 25, 36-40, 49, 60 by R. P. Whitfield ) '""'^*<"'' Legend : t. Teeth. b. Dental sockets. s Median eeptum (nedicle-valve). h Hi" e lat ''■ ''^'"*' ^'' '^^'"'^" septum (brachial valve). Genus RETZIA, King. Page 103. Retzia Adrieni, de Verneuil. Figs. 1, 2. Doi-sal and ventral views of a typical sj.ecimen ; showing- I he charactere of the exterior Hg. 6. A dorsal view of a smaller example, from which a poi-tion uf the brachial valve has been removed exposing the median septum and a portion of ( ne of the spiral cones. ' *1g. 4. An enlarged view of a shell which has been transversely sectioned just in front of the umbones- showing- the hinge-plate, dental sockets and median seiitum. ' Fig. 5. The interior of a portion of the brachial valve ; showing the hinge-plate and median septum. TO o f°?*'"'^^°&"'«'«''''« ™I'ied from CEiiLERT, AnnalesSci. Geol., t. xix, No. 1. Iis86 Fig. 6. A dorsal view of a somewhat flattened example. Fig. 7. A more rotund individual, imperfect about the ante-lateral margin. Fig. 8. A view of a similar specimen of larger size. Fig. 9. A dorsal view of the umbonal region of conjoined valves; showing the excavate cardinal slopes of the pedicle-valve and the concave coalesced deltidial plates. X 2. Lower Devonian. Departeinent de la Sarthe, France. Genus PTYCHOSPIRA, gen. nov. PiiRe 112. Pttchospika FERrrA, voii Buch. Fig, 10. A profile view of an average individual ; showing the coai-se plication, and the extension of the anterior margin. X 2. Fig. 11. A dorsal view of the same B|)ecimen ; showing the coalesced deltidial ]>lates. X 2. Middle Devonian. Bifet, Oermany Pttchospika lonoirostris, Kayscr. Fig. 12. A dorsal view of a specimen ; showing the narrow and elevated beak of the pedicle-valve. Middle Devonian. Bifel, Oermany. Ptychospira (cf.) SEXPLiCATA, Wliito iiiid Whitfield. Figs. 13, 14. Dorsal and ventral views of a specimen, probably referable to this species. Burlington limestone. Burlington, Itrwa. Subgenus HOMCEOSPIKA, s.-gen. nov. V&t^e Hi. HOMCEOSPIRA EVAX, Hall. Fig. 15. A doi-sal view of the youngest shell observed. In this stage of growth the beak of the pedicle- valve is erect and the deltidial plates not developed ; the surface of the valves is smooth and evidence of plications is visible only outside of the second concentric growth-line. X 25. Figs. 16, 17. Profile and dorsal views of a full-grown .specimen ; showing the adult characters of the exterior. Fig. 18. The umbonal region of a young shell in which the deltidial plates have united at the base, enclos- ing an oval foramen. X 7. Rg. 19. A similar view of a moi-e fully grown individual with unusually erect beak and nearly ovate foramen. X 3. Fig. 20. The interior umbonal portion of a fully-matured example ; showing the complete obsolescence of the deltidial plates and the enclosure of the foramen by the substance of the valve ; also the projecting, recurved teeth. X 2. Niagara group. Waldron, Indiana. Genus RHYNCHOSPIRA, Hall. Page 108. RhYNCHOSPIRA FORMOSA, Hall. Fig. 21. A dorsal view of a typical si)ecimen j showing the character of the exterior. Fig. 22. The interior of the cardinal portion of the pedicle-valve of a normal adult; showing the circular foramen, the completely coalesced deltidial jilate-s, and the teeth. X 2. Fig. 23. The interior of a pedicle-valve ; showing similar charactera with less detail. Fig. 24. The interior of a brachial valve j showing the form of the hinge-plate, the dental sockets and the median sentum. Fig. 25. An interior view of the cardinal portion of articulated valves ; showing the elevation of the hinge- plate, and the median septum of the brachial valve, and the muscular depression of the pedicle-valve. X 2. Lower Helderberg group (Shaly limestone). The Helderbergs, N. Y. ri.ATE, L— Continued. Subgenus HOMCEOSPIRA, s.-oen. nov. I'age Hi. HoMCEosriKA SOBKINA, IJccchor and Clarke. Fig'. 36. A ventral view of an in)oi-8mI views; showing llio convexity of the valves and the character of the plica- tion and concentric ornamentation. X 2. Niagara group. IValdron, Indiana. Genus RHYNCHOSPIRA, Hall. I'aite 108. RHYNCHOSPIRA Electra, Billiiigs. Figs. 29-31. DorsaJ, ventral and i>rotile views of the original specimen. Lower Helderbei-g group. Square Lake, Maine. Subgenus IiOM(-EOSPIRA, s. gen. nov. Homceospira (cf.) EVAX, Hall. Fig. 82. A dorsal view of an average specimen ; showing the chara4;ter of the deltidial plates and the sur- face plications. X 2. Fig. 3.S. The interior of a pedicle-valve. Fig. 34. The interior of a brachial valve; showing the hinge-plate and median septum. X 2. Fig. 35. The cardinal portion of the last specimen, enlarged to show in more detail the structure of the hinge-plate. X 5. Upper Silui-ian. Perry couTiiy, Tennessee. Genus TRIGERIA, Batle. Page 265. Trioeria lepida, Hall. Figs. 36-38.- Dorsal, ventral and profile views of a typical specimen ; showing the character of the exterior and the form of the deltidial plates. X 2. Fig. 39. A doi-sal view of a moi-e elongate shell, with a pronounced median sinus on the brachial valve. X 2. Fig. 40. An enlargement of the umbonal region of the specimen represented in tig. 36 ; showing the delti- dial plates, the foi-m of the foramen and its encTOachment upon the apex of the valve. X 6. Hamilton group. Canandaigua Lake, N. Y. (The lithographing of this plate was completed before the discovery of the fact that this species is a terebratuloid allied to Rk.ns8kl.«kia, and referable to the genus Tbiqbbia, Bayle, as inter- preted in this woik.) Genus RHYNCHOSPIRA, Hall. PaKC 108. Rhynchospira (?) P^ugenia, Billings. Figs. 41-43. Dorsal, ventral and profile views of a specimen; showing the usual form of exterior at this locality. X 2. Hamilton gi-oup. Yin-k, N. T. Rhynchospira (?), sp. Fig. 44. A view of the exterior of a i>edicle-valve, the only specimen of the species observed, and referred to this genus with doubt. Waverly group. NorthtDestem Pennsylvania. Rhynchospira scansa, sp. nov. Fig. 45. A view of the exterior of a pedicle-valve ; showing a median sulcus similar to that occurring in the typical i-epresentatives of the genus. Waverly group. McKean county, Pennsylvania. Genus CA.MAROSPIRA, gen. nov. Page Si Camarospira Eucharis, Hall. Figs. 48, 47. Dorsal and ventral views of the exterior. The position of the median septum is seen through the shell-substance on each valve. Fig. 48. A profile view ; showing the convexity of the valves. Corniferous limestone. Cass county, Indiana. Fig. 49. A dorsal view of the original example of CamaropJioria Eucharis ; showing a rather more pro- nounced median fold on the brachial valve. Fig. 50. A ventral view of a specimen broken so as to expose the spondylium of the pedicle-valve. Cornifei"oU8 limestone. Cayuga, Ontario. Vig. 61. A median longitudinal section ; showing the sjiondylium and supporting septum ef the pedicle- valve and the septum of the brachial valve. X H- Hg. 52. A transvei'se section in the umbonal region ; showing the spondylium and septa. X H. Corniferous limestone. Cass county, Indiana. m si=^(BSiaii2P ©iffli;^ Palaont.NY.Vol.IYPtii'Vol.vm. Oeiit'rir Illustrations. Plate L . %ii ^-. # -j?^ ;IR^ 36 k Wlh 4^ >Ak ML '\ /'ill*' 4 4. 90 hp # ^ 40 4e 47 48 - VI QB Simpson del Phil.Astlith. Fig. Fig. 5. 6. 7. Fig. 8. Fig. 9. PLATE LI. (Fignrea 1-7, 13-16, 18, 23-28, 28, 29, 31-41 by G. B. Simpson; 8, fl, 20-22 by J. M. Clabke; 17 by F. B. Meek; 19,27, 30 by E. Emmons; 10-12 copies.) Genus HUSTEDIA, gen. nov. Page 1-20. HuSTEDIA MORMONI, Maicou. Figs. 1-4. Ventral, dorsal, frontal and profile views of an average individual ; showing the coarse plication of the surface. An enlarged view of the exterior of the pedicle-valve. X 2. The opposite side of the same specimen ; showing the coalesced deltidial plates. X 2. An enlargement of the umbonal region ; showing the coalesced deltidial plates, and the flattened cardinal slopes of the brachial valve. X 5. A preparation of the hinge-plate, viewed from in front ; showing the elevation of the large recui-ved median part, the crural lobes, and the pi-ojection of the antei'ior ligulate process. A profile view of the same specimen ; showing the great recurvature of the body of the plate, the direction of the crural processes, and the extent of the anterior ligulate process. X 5. (c.) Coal Measures. Near Kansas City, Missouri. Genus UNCINELLA, Waagen. Page 123. Uncinella typica, Waagen. Figs. 10-12. Dorsal, profile and ventral views of a typical specimen ; showing the exterior characters. (Waagbn.) Permo-carbonifei-ouB. Salt- Range, India. Genus EUMETRIA, Hall. Page 115. Eumetkia Veuneuiliana, Hall. Figs. 13, 14. Dorsal and profile views of an unusually elongate shell. Figs. 15, 16 Similar views of an example which has the usual form of the species. Fig. 17. A dorsal view of the original sj)ecimen of the species, enlarged. In all the above specimens the deltidial plates are seen to be wholly coalesced, which is the nor- mal condition at maturity. Fig. 18. A doi-sal view of a small individual in which the median division-line between the deltidial plates is still retained. X 3. This and the preceding figure represent the species as it occurs in the limestone at this locality. Fig. 19. The detached brachidiura, enlarged, and viewed from the ventral side ; showing the attachment of the crura to the primary lamellse, the form of the loop, its long, straight bifurcate stem, and the shape of the spiral cones. X 2. (c.) Fig. 20. The inferior of the caiilinal region of articulated valves, viewed with the plane of the hinge hori- zontal. This preparation shows, in the background, the large foramen and below it the flattened inner surface of the coalesced deltidial plates, which afford no evidence of a median suture. On either side are the elongate teeth filling the equally elongate dental sockets. The hinge-plate consists of two parts, (a) the posterior portion which takes the form of a crescent, its hoins lying back upon the inner sui-face of the deltidial plates and the umbonal slopes ; this is connected laterally with the socket-walls and anterioi-ly with (6), the anterior portion, which is tent-shaped and consists of two deep and bread lateral lamellae resting on the bottom of the valve, united above by a deeply concave horizontal plate ; from the anterior angles formed by the union of these plates arise the divergent and greatly elevated crural processes. In this figure the anterior portion of this apparatus is considerably foreshortened. It will be observed that the specimen shows no evidence of the delthyrial tube occui-ring in Retzia, Hustbdia, etc. X 10. (c.) Fig. 21. The same preparation viewed with the pedicle-valve inclined upward ; showing the length of the anterior transverse plate. X 5. Fig. 22. A view of the same specimen with the pedicle-valve inclined downward ; showing the elevation of the crural plates and processes. X 5. St. Louis group. Spergen Hill, Indiana. Fig. 33. An internal cast of a brachial valve which retains a portion of the hinge-plate and shows the back- wani projection of the posterior crescent. Fig. 24. A dorsal view of a specimen, drawn from the impression of a natural mould represented in fig. 25. Fig. 25. k mould of the exterior of a portion of both valves. Fig. 26. The umbonal portion of the same specimen, enlarged ; showing the maximum development of the foraminal tube, which is but a slightly introverted lamina. The figure was also designed to represent the separation along the hinge-line of the deltidial plates from the flattened cardinal surfaces of the brachial valve, b it by an error in the lithography this line has been made to appear as a break continuous with a slight fracture on each side of the pedicle-valve. X 3. St. Louis group. Chreene county, Missouri. PLATS U— ContiDued. EUMETRIA VEKA, Vlir. COSTATA, llilll. fig. 27. The cardinal portion of a i>edicle-valve J showing the completely coalesced deltidial plates. X 3. Fig. 38. A view of a jieilicle-valve from which the shell has been partially exfoliated ; showing the faintly defined muscular area. Figs. 31, 83. Dorsal and profile views of the same specimen. Chester limestone. Crittenden county, Kentucky. Fi(f. 29. A dorsal view of a specimen from which the shell has been exfoliated, exposing the elongate, narrow muscular impi-ession of the brachial valve. Fig. 30. The upper half of a preparation of the brachidium ; showing iu the solid opaque matrix the attachment of the crura to the primary lamellie, and thu bifurcate extremity of the loop. X 2. Chester limestone. Chexter, Illinois. Kg. 33. The intei-ior of the urabonal portion of a brachial valve ; showing the posterior horns of the hinge- plate, the concave median plate and the elongate, narrow dental sockets. The crural plates and their processes have been lost. X 3. Chester group. Crittenden county, Kentucky. EuMETRIA VeRNEUILIANA, Hilll. Figs. 34, 35. Doi-sal and profile views of a specimen with coarse surface plications. St. Louis group. Spergen Hill, Indiana. Eumetkia vera, Hall. Fig. 36. The umbonal portion of an old shell enlarged to show the thickening of the coalesced deltidial plates which have become conspicuously protuberant. This thickening has been accompanied by a similar growth on the brachial valve which has rendered the flattened cardinal expansion very prominent, as seen on the right of the beak. The growth of the brachial valve has been somewhat unsynimeti-ical. X 2 Pig. 37. The umbonal portion of a specimen which has been broken longitudinally neai-ly in the median axis. On the upper portion is exposed the surface of the more di.slant of the two crural plates, flattened below by the transverse concave jilate and the upward extension of the nearer of the crural plates. The outei- shell is retained about the beak of the pedicle-valve. X li. Chester group. Crittenden county, Kentucky. The distinction between the three forms of Eombtria here i-epresented is one not easy to carry out with an abundance of material. Eumetria VtrJinuiliana was founded upon the small, very finely plicated shells from the white limestones at Spergen Hill, Ind., but it was suggested in the original description that the larger shells occurring in a silicified condition at the same locality and elsewhere, are of the same species. B. vera was based upon specimens of about the same size aa the latter, with a somewhat c^)ar8er plication, derived from the Kaskaskia (Chester) limestone at Chester, Illinois, and E. vera, var. costata on larger and more coarsely plicated shells from the same locality. It is very fiequently difficult, notwithstanding the slight differences in geological horizon, to distinguish th« larger form of E. Vemeuiliana from the typ- ical form of E. vera, while a distinction between the two forms of E. Vemeuiliana occuring at Spergen Hill is often more readily made. Genus ACAMBONA, White. Vagc 119. Aoambona? Osagensis, Swallow. Fig. 38. A dorsal view of an imperfect specimen of the Setzia Osagensis, Swallow, which will probably prove to Iwlong to this genus. Fig. 89. A portion of the surface of the shell enlarged. The lower part of the figure represents the puncta- tions of the outer surface, where it has been exposed and somewhat weathered ; above is the surface of one of the inner layers coveied with fine pustules. The plications are much more distinctly defined on the inner layers, but they are not obsolete on the outer layer as here represented. X 5. Choteau limestone. Pike county, Missouri. Aoambona prima, White. Figs. 40, 41. Dorsal and profile views of an incomplete specimen which is regarded as belonging to this species. Burlington limestone. Burlington, Iowa. Pal8eont,N,Y.Vol.IV,Pt.n-Vol.Vra. m m. ^ (s m E ® IP m m £^ RETZIID*. Generic lUiisirations. Plate LI. Q B.Simpeon del. Phil.Ast.hih. PLATE LII. (Figares 1-15 by G. B. Simpson; 16-19 by E. Emmons; 20-36 copies.) Genus CLINTONELLA. gen. nov. Page 159. ClINTONELLA VAGABUNDA, S|). uov. Fig'. 1. A dorsal view of an internal cast retaining the siiell on the umbo of the pedicle-valve. Below the foramen is seen a portion of the lower surface of the hinge-plate. Fig. 2. A view of another specimen similarly jireserved, though the hinge-plate is wholly removed. Fig. 3. A profile of the same specimen ; showing the normal convexity of the valves and the elevation of the median foleortion of the brachial valve ; showing the recurved hinge-plate, deep dental sockets and median ridge. X 3. Fig. 37. The exterior of a pedicle-valve slightly imjiei-fect about the margins. X '■i- Fig. 38. The interior of the same specimen ; showing the open delthyrium and teeth. X 2. Corniferous limestone. Waterlmt, N. Y. Fig, 39. The interioi- of a brachial valve with faint lateral plications ; showing the hinge-plate, dental sockets and median ridge. Ciorniferous limestone. Sangerfield, N. Y. Genus LEPTOCCELIA, Hall. Leptocoxia flabellites, Hall. Pigs. 40-42. Dorsal, ventral and protile views of an average example ; showing the contour and sui-face characters. Fig. 43. The interior of a brachial valve ; showing the structure of the hinge-plate, dental sockets and muscular area. Vlg. 44. A profile of a large shell ; showing the plano-convex contour. Kg. 4S. The interior of a brachial valve, somewhat imperfect about the margins j showing a slight varia- tion of the charactei's as represented in fig. 43. Fig. 46. The cardinal region of another brachial valve, enlarged ; showing the excavation of the cardinal process on either side of a median ridge, and the projection of the crural lobes. X 2. Fig. 53. The interior of a i5erift blocks in central and western New York. Fig. 21. The exterior of a pedicle-valve ; showing its contour and the tine surface plication. Hudson River group. Hamilton, Ontario. Fig. 22. The interior of a pedicle-valve ; showing the cardinal process and muscular scars. From a gutta- percha mould. Fig. 23. An enlargement of the cai-dinal process of the same specimen ; showing its bilobate character. X3. Hudson River group, Ihift blocks of central New Yoi-k. PLATB UV— CoDUnneit. SuBOKNus CATAZYGA, s.-oen. nov. Pnge.l.'iT. C'atazyga IIeadi, liillings. Figs 24-36. Dorsal, nrotile aiul cardinal views of the exterior ; allowing the biconvex valves, the tine plica- tion of the exterior and the median depression on the brachial valve. Natural size. Hudson River group. Near Ottawa, Canada. Figa. S8, 39. Dorsal and proBle views of another specimen. Hudson River group. Near Cincinnati, Ohio. Vig. 80. The interior of a jwrtion of the pedicle-valve ; showing the deep muscular scar. Hudson River group. WayntitviUe, Indiana. Catazyoa Headi, viir. bokealis, Billings. Fig. 87. A dorsal view of a rather large sjiecimen of this variety. Hudson River group. Waynesville, Indiana. Figa. 81, 82. Dorsal and profile views of a smaller shell. Anticosti group. Island of Anticosti. Catazyoa Headi, var. Anticostiensis, Billings. Fig. 83, 84. Ventral and dorsal views of the exterior; showing the outline, contour and tine surface plication. Hudson River group. CoUingiDood, Ontario. Genus ZYGOSPIRA, Hall. Page 151. Zygosi'ira putilla, sp. nov. Figs. 86-37. Dorsal, profile and ventral views of the exterior of an average example. X 2. Hudson River group. Near Edgewood, Pike county, Missouri. Genus CYCLOSPIRA, gen. nov. Page 146. Cyclosi'ira bisulcata, Emmons. Figs. 38-40. Dorsal, profile and ventral views of the exterior of a specimen bearing a marginal plication in the sinus of the brachial valve. X 2. Trenton limestone. Watertovm, N. T. Genus DAYIA, Davidson. Page 62. Dayia navicula, Sowerby. Figs. 41-43. Dorsal, frontal and profile views of an average example, enlarged. Fig. 44. A restoration showing the character of the spirals and loop. Figs. 45, 46. Enlarged translucent preparations of the spirals ; showing the lateral direction of the apices and the fimiji-iation of the 8|>iral coils. (Davidsok.) Ludlow shales. Shropshire, England. Genus PROTOZYGA, gen. nov. Page 151. Protozyga exioua, Hall. Figs. 47, 48. Ventral ami dorsal views of a specimen ( showing the naviculate contour and smooth exterior. Shells of this S)>ecies usually bear one or two low, broad marginal folds on each side of the metlian axis. X 2. Trenton limestcme. IVatertown, N. Y. 33 Si^SSJUlDIP (BEi^ Palaeont. N Y.Vol.rV-Pt,li= Vol.Vm. ZYOOSViniD.V. Geixeric lUuslrations. Plate Liy- QB. Simpson del PM.Asthtli. PLATE LV. (Figores 1 by J. M. Clarke; 2, 11, 12, 16-17 by G. B. Simpson; 3-9, 18-21, 23, 26, 27 by R. P. Whitfield; 10, 13, 14, 22, 24, 25 by E. Emmons.) Legend : P. Pedicle passage. p. Pedicle cavity. dp. Deltidial plates. hp. Hinge-plate. c. Crural lobes. b. Dental sockets. Fig. Fig. Figs. Kg. Fig. Fig. Ridge in dental sockets. Adductor scars. Diductor scars. Ovarian markings. Vascular trunks. Secondary vascular sinuses. Fig. Fig. Figs. Figs. Fig. Fig. Fig. Genus ATRYFA, Dalman. Page 163. Atrypa reticularis, Linii6. 1. Dorsal view of the youngest individual observed ; showing the slight convexity of the brachial valve in the umbonal region, its general depression anteiiorly, low median sinuSi few plications, erect beak of pedicle- valve, triangular delthyrium and incipient deltidial plates. X 10. 2. Exterior of the pedicle-valve of a mature indiviciual from the same locality ; showing the exten- sions of the concentric lamellae. Niagara group. Waldron, Indiana. 3. 4. Dorsal and profile views of an elongate, finely plicate and gibbous shell, without strong con- centric growth lines. Lower Helderberg group (Shaly limestone). Near Clarksville, N. Y. 5, 6. Dorsal and profile views of an orbicular, subequally Vnconvex, finely plicate shell. 7. The interior of a pedicle-valve ; showing the broad pedicle cavity, widely separated teeth, pedicle, adductor and diductor muscular scars, ovarian markings and crenulated ante-lateral margins. 8. The interior of a brachial valve ; showing the structure of the hinge- plate, dental sockets and the muscular scars. Hamilton group. In the soft shales of vxstem New York. 9. An internal cast of a large pedicle-valve ; showing the impression of the rostral cavity and large muscular scars, ovarian mai-kings, vascular trunlis and secondary sinuses. Corniferous limestone. Le Roy, N. Y. Fig. 10. A preparation exposing the brachidium of a large individual, by the removal of the brachial valve. The spiral cones have their bases parallel to the surface of the pedicle-valve and their apices directed upward and inward, into the cavity of the convex brachial valve. The figure shows the laterally appressed form of the cones, the great width and anterior extension of the primary lamellae, the attachment of the latter to the crura, and the discrete, recurved branches of the loop. (c.) Chemung group. Haskins^rille, N. Y. The cardinal portion of the brachial valve, enlarged ; showing the reduced and completely divided hinge-plate, and the broad dental sockets which are traversed by a crenulated median ridge. X3. A posterior view of the cardinal portion of the pedicle-valve ; showing the elevation of the distant teeth, the double grooving and recurvature of their extremities. X 3. 13, 14. Fragments of the spiral lamellae ; showing their fimV)riate outer margin. X 10. 16. A portion of the primary lamellae with its attachment to one of the crura. This specimen is viewed from the dorsal side and shows the incurvature of the crus and its union with the outer edge of the lamella. X 10. 16. A view of the loop drawn from the ventral side of the brachidium ; showing the thickened and recurved extremities of the lateral branches. X 10. 17. A portion of the primary lamellae and one of the crura, the latter being in a pathologic condition which has resulted in hypertrophy of this part. X 10. Hamilton group. Clarke county, Indiana. 11. 12. PLATE I.V— Continaed. Atkypa aspera, Schlothoiin, v;ir. occidentalis, Hall. Flga, 18. 10. DonuU and pi-otile views of a Devonian shell ; showings the gibbosity of the brachial valve, the coarse plications and strong concentric lainellte. Fijr. 20. A preparation of the brachidinm exposed by the I'emoval of the jiedicle- valve ; showing the form of the cones and loop. (Whitfield ) Upper Devonian. Ind^eadence, Iowa. Athypa spinosa, Hall. Fig. 21. The exterior of the i>edicle-valve ; showing the extension of the concentric lamellte into well- defined spinules. When these spinides are removed such shells present coai-se, strong plications like those of A. aipera. Hamilton group. Moscou), N. Y. Kig. 22. Dorsal view of a siieciraen with longer spines. A poi-tion of the brachial valve has been removed, showing one of the spii-al cones, which is con.'^iderably depre-ised. Hamilton gi-oup. Canandaigtui Lake, N. Y. Atrypa hystrix, Hiill. Fig. 38. The exterior of a pedicle-valve, with coarse ribs, strong concentric lamella! and stout, long mar- ginal spines. Chemung group. Near Bath, Steuben county, N. Y. .\trypa marginaus, Dalinaii. Kigs. 24, 2&. Dorsal and profile views of a preparation showing the brachidium which has been exposed by the removal of the brachial valve. The spiral cones are more regularly conical ann River grroup. Iron Ridge, Wisconsin. Fig. 22. The interior of an old brachial valve ; showing the deflection of the cardinal process and the thickenetl hinge-jjlate. Rg. 28. The interior of a jiedide-valve in which the deltidial plates have been partially resorbed, leaving the j>e«licle cavity open and exposing a well derined pedicle scar. The impression of the diductor muscles is large and exi>and('d, indicatintr that the contraction of the scar with aee, as seen in 6gure 17, is due to the encroachment of testaceous deposits upon the area of muscular insertion. Hudson River group. Bichmimd, Indiana. Fin. 34-97. Dorsal, ventral, pi-ofile and frontal views of a young shell which, at an eai ly growth-stage, suf- fered an interruption to the regular development of its jilications on both valves, the subsecjuent shell-growth being irit^gular and showing but an imperfect development of the plications. The cessation of uorinnl growth at the same stage on both valves would indicate that the production of the al)norinal shell was due to a pathologic cotidition of the mantle, which has thtis repro- duced in the later development of the valves, an elementary condition of growth. Hudson River group. Near Cincinnati, Ohio. Genus CAMAROTCECPIIA, gen. nov. I'age 1J9. CaMAROTCECIIIA FKINGILLA, Billillg.S. Figs. 38-30. Dorsal, profile and ventral views of a large and finely developed individual ; showing the ex- ternal characters of the species. Anticosti group. Oull Cape, Anticosti. Genus RHYNCIIOTRETA, Hall. I'ago 1S5. Rhynciiotreta cuneata, Daliiuiii, var. Amekicana, Htill. Piga. 31-34. Dorsal, profile, ventral and fiontal views of an average example ; showing the contour of the shell, the character of the plication and fine concentric surface markings. Plj. 86. Doreal view of the youngest individual observed ; .showing the open delthyrium, broad umbones and the median sinus on the bi-achial valve. X 6. (After Brrchkr and Clarkb.) Niagara group. Waldron, Indiana. Figs. 36, 37. Ventral and dorsal views of an internal cast of conjoined valves ; showing, in figure 36, the impression of the ]>edicle muscle, the diductor and adductor scars bounded by divergent ridges, and, in figure 37, the cast of the deltidiiil cavity and the extent of the meiiian septum. Niagara dolomites. Near Milwaukee, Wi.icon.nn. Fig. 38. The cardinal region of an adult specimen, enlarged ; showing the unusual size of the deltidial plates, their outward flexion along the median suture, the apical and encroaching position of the foramen. X 5. (After Bbechkr and Clarke.) Niagara group. Waldron, Indiana. Rhynchotreta cune.\ta, Daliiiiin. Figs. 39, 40. Profile and dorsal views of a normal adult. (After Davidson.) Weidock limestone. Dtidliy, England. Genus STENOSCHISMA, Conrad. Page 187. StENOSCHISMA FORMOSA, Hall. Flga. 41-43. Dorsal, profile and ventral views of the exterior. Fig. 44. Frontal view of another example. Y\g. 45. Enlargement of the hinge-plate ; showing its deep median division, miiuite cardinal process, flat cmral lobes and concave crura. X 4. Lower Heldei'bei-g group (See Vol. Ill, p. 286, pi, xxxv). Albany amnty, N. T. IB lB.^CBISn®IP (D2Ei^ Palaeont . N. Y. Vol . IV Pt.ii ■= Vol .vm. Htn'NCHOX E LLIDA (TeiieTir llliistriitions. Plate LVI QB.SimpEOii del Jr'hil.AsliiUi. PLATE LVII. (Figures 1-50 by B. P. Whitfield; 51-54 by E. Emmons.) Genus CAMAROTCECHIA, gen. nov. Page 189. CAMAROTfECHiA Tethys, Billings. Figs. 1, 2. Cardinal and profile views of a rather large shell. Corniferous limestone. Province of Ontario. Camarotcechia Billinqsi, Hall. Fig. 3. Doraal view of an internal cast ; showing the position of the median septum. Corniferous limestone. Western New York. Camarotcechia Carolina, Hall. Figs. 4, 5. Dorsal and cardinal views of a partially exfoliated specimen. Fig. 6. Front view of a more gibbous shell. Corniferous limestone. SaTidusky, Ohio. Camarotcechia Horsfordi, Hall, Figs. 7-9. Cardinal, frontal and profile views of a typical mature individual. Hamilton shales. Moscow, N. Y. Camarotcechia Sappho, Hall. Figs. 10-14. Dorsal, vCntral, cardinal, profile and frontal views of a large and typical example. Hamilton group. Western New York. Camarotcechia congregata. Hall. Pigs. 15-19. Dorsal, ventral, cardinal, frontal and profile views of a large individual. Fig. 20. Cardinal view of an internal cast ; showing the cavities of the dental plates and median septum. Fig. 21. An internal cast of the pedicle-valve ; showing a lai-ge diductor impression. Fig. 22. A similar cast of the interior with the muaculai' ai-ea more restricted. Pig. 23. An internal cast of a brachial valve ; showing the length of the median septum, the filling of the cardinal cavity and the scars of the adductor muscles. Figs. 24, 25. Enlargements of the internal casts of the umbonal portion of the brachial valve ; showing the filling of the incipient spondylium and the crenulation of the outer socket-walls. FigB. 26, 27. The same parts drawn from gutta percha impressions taken from natural casts of other indi- viduals ; showing the broad hinge-plate with its median division terminating in a spondylium, which is supported by branches of the median septum. Hamilton group. Varioiis localities in the sandy shales of Schoharie, Otsego and Madi- son counties, N. Y. Camarotcechia contracta. Hall. Figs. 28, 29, 31. Dorsal, profile and frontal views of an internal cast. Figs. 30, 32. Dorsal and cardinal views of a cast with coarser plicalions on the median fold. Chemung gfroup. Central and western New York. Camarotcechia Stevensi (= Rhynchonella Stephani), Hall. Fig. 33. An internal cast of the pedicle-valve. Figs. 34, 35. Dorsal and cardinal views of a cast of the brachial valve ; showing the filling of the spondy- lium and the length of the median septum. Chemung group. Bradford county, Pennsylvania. PI.ATK LVn— Continued. CaMAROTcECHIA (?) UUPUCATA, Hull. FtCB. M-38. Ventral, frontal aniai{ot(echia orbicularis, Hall. Fig. 46. An internal cast of a brachial valve ; showing the cast of the spondylium. Fig. 47. Cardinal view of an internal cast ; showing the filling of the rostral cavity and the extent of the thickened median septum. Fig. 48. An internal cast of the iiedicle-valve ; showing the adductor and diductor muscles and the ovarian markings. Fig. 50. An enlargement of a i>ortion of the interior of the pedicle-valve ; showing the detailed structure of the muscular impression. Chemung gfroup. Meadtnlh, Pennsylvania. Camarotcechia contracta, Hall. Fig. 49. An internal cast of the pedicle-valve ; showing the form of the muscular area. (See figs. 28-32.) Hamilton gi-oup. Near Cardiff, N. Y. C'AMAR0T(ECHIA, sp. ? Figs. 61-58. Ventral, profile and dorsal views of an internal cast in chert. Burlington limestone. Burlington, Iowa. Camaroixechia, sp. indet. Fig. 54. Cardinal view of an exti'emeiy gibbous intei-nal cast ; showing the Slling of the muscular cavity in the pedicle-valve and the spondylium in the brachial valve, the cavities left by the dental plates, hinge-plate, crura and median septum. Waverly group. Ohio. m iii^(B3iii®iF miE^ Paleeont.N.Y.Vol.rv.Pt.ii'Vol.vm. RHYNCHONEI.I.IDA-. Generic llUistratioiis. Plate LVIL R.P. Whitfield del Phil.Ast.lith. PLATE LVIII. (Figures I-IO, 18-19, U, 25, 36, 40 by U B. SIMPSON; U, 12, U, 35 by K. Emmons; 13, 20-23, 26-33 'by F. B. MEEK.) Gknus KHYNCHOPORA, King Page 210. Rhynchopoka PU8TULOSA, While. Figs. 1-4. Doi'sal, ventral, front and profile views of an avei age example. Burlington limestone. Burlington, Iowa. Genus WILSONIA, (Quenstedt) Kaysek. Page 195 WiLSONiA Saffokdi, Hllll. Figs. 5-7, 10. Dorsal, ventral, frontal and profile views of a normal adult individual. Figs. 8, 9. Front and profile views of another specimen, with bi-oader median fold and greater anterior gibbosity. Fig. 11. llie interior of a pedicle-valve ; showing the teeth and muscular impressions. X 2. Fig. 12. Cardinal view of an internal cast of conjoined valves ; showing the muscular impressions and the cavities left by the dental plates and median septum. X 2. Niagara group. Perry county, Tennessee. WiLSONIA VENTKIC08A, HuU. Fig. 13. Profile view of an average specimen ; showing the extreme gibbosity of the valves. Kig. 14. The interior of a thickened pedicle-valve ; showing the scars of the pedicle and diductor muscles. Lower Helderberg group (Upper Pentamerus limestone). Schoharie county, N. Y. Genus UNCINULU8, Bayle. Page 195. Uncinulus abruptus, Hall. Fig. 15. The interior of the umbonal portion of the pedicle-valve ; showing the marginal teeth with dental plates lying close against the shell-walls. X 2. Fig. 16. Cardinal view of the articulating apparatus of the brachial valve of a young shell j showing the triangular, divided cardinal process and the elevation of the crura. X 3. Figs. 17, 18. Two views of the corresponding parts in an adult shell in which the lobes of the cardinal pro- cess and the lateral portions of the hinge-plate are considerably thickened. X 2. Fig. 19. The interior of a pedicle-valve ; showing the faintly defined muscular scar. Figs. 20, 21. Dorsal and front views of conjoined valves of a typical specimen. Lower Helderberg group (Shaly limestone). Albany and Schoharie counties, N. T. Uncinulus mutabilis, Hall. Figs. 22, 23. Profile and front views of a mature shell ; showing its subspherical shape. Figs. 24, 26. Two views of the interior umbonal region of the brachial valve ; showing the thickened median septum, curved and elevated crura and bilobed cardinal process. X 1^. Lower Helderberg group (Shaly limestone). Albany and Schoharie counties, N. T. Uncinulus nobilis, Hall. Fig. 26. Front marginal view of an adult shell. Lower Helderberg group (Upper Pentamerus limestone.) Albany and Schoharie counties, JX. Y. Uncinulus pyramidatus, Hall. Figs. 27, 28. Profile and front views of an average specimen. Lower Helderberg group (Shaly limestone). Albany county, N. Y. PLATE LTin— CoDtinaed. Subgenus PLETIIORHYNCHA, s.-qen. nov. Page 191. PlETHORHYNCHA 8PECIOSA, Hilll. Figv. 29-31. Cardinal, front and profile views of a large entire individual ; showing the robust form of the shell, its subquadrate transvei'se section, serrate margins and broad, somewhat concave lateral 8lo|>es. The abrupt marginal extensions of the cardinal slopes of the pedicle- valve, fitting into corresponding excavations of the brachial valve, as shown in figures 29 and 30, ai-e the thirkened teeth which are cemented to the walls of the shell throughout their entire extent and, at their summits only, fitted into shallow sockets in the opposite valve. Rg. 32. The interior of a brachial valve, slightly bi-oken about the mai'gins ; showing a thickened, undi- vided hinge-plate, bilobed cardinal pi-ocess, narrow dental sockets and the median septum. Kg. 33. A canlinal view of the same specimen ; showing the elevation of the cardinal process and crura and the marginal excavations for the reception of the teeth. Fig. 34. Cai-dinal view of the umbonal portion of an old shell in which the entire hinge-plate has become greatly thickened and elevated, and the apical portion or cardinal process resorbed and exca- vated. The projecting points above ai-e the bases of the cmra. Rg. 35. The interior of a small pedicle-valve ; showing the form of the teeth, and faint median muscular ridge on the bottom of the valve. Kg. 36. The interior of a young brachial valve in which the hinge-plate is divided, its lateral portions rest- ing on the median septum, and the cai-dinal margins but slightly excavated for the reception of the teeth. Kg. 37. The umbonal portion of the same specimen, enlarged ; showing the small cardinal process and the median division of the hinge-plate resting on the septum and forming an incipient spondylium. X 2. Oriskany sandstone. Cumberland, Maryland. Genus UNCINULUS, Bayle. Page 196. Uncinulus (Unoinulina) Stuicklandi, Sovverby. Fig. 38. Cardinal view of an internal cast of both valves, the brachial valve I>eing represented above ; showing the cavities representing the median septum, the cardinal process and hinge-plate, and the ridge filling the median division of the latter. • Niagara dolomites. Near Milvxiukee, Wisconsin. Figs. 89, 40. Dorsal and cardinal views of the exterior of a normal adult ; showing the low median fold and the smooth cardinal slopes. Niagara g^oup. Waldron, Indiana. 33.JS.(S3I2(I)IP CDln:).iS. Palseont.N,Y.Vol.IVPt.ii=Vol.vm^ liHYNCHOXKI.l.ID.Y. (uMiciii' Illiisli-.itiim^ PlateLVni G B. Simpson del. Phil.Ast.lith. PLATE LIX. (Figs. 1-12, 18-22, 26, 30, 31, 37, 38 by R. P. Whitfield; 13, 14, 24, 25, 28, 29, 32, 33 by E. Ehmons: 16-17, 23, 27, 34-SS by Q. B. Simpson.) Genus LIORHYNCHUS, Hall. Page 193. LlORHYNCHUS LIMITAEIS, VailUXeill. Figs. 1, 2. Dorsal and frontal views of a small individual. Marcellus shales (Gouiatite limestone). iScJioharie connty, N. Y. Figs. 3-5. Frontal, cardinal and ventral views of a larger specimen. Limestone of the Marcellus shales. Avon, N. Y. LlORHYNCHUS DUBIUS, Hall. Figs. 6, 7. Ventral and dorsal views of a typical specimen. Marcellus shales. Locality f LlORHYNCHUS MULTICOSTA, Hall. Fig. 8. The exterior of a pedicle-valve of an elongate specimen, the regular gi-owth of which has been inteiTU])ted in the umbonal region. Fig. 9. The brachial valve of a more orbicular and typical shell. Pig. 10. A cardinal view ; showing the convexity of the tvalves. Hamilton group. Western New York. LlORHYNCHUS MESACOSTALIS, Hall. Fig. 11. The exterior of the pedicle-valve ; showing the inequal plication of the sinus. Fig. 12. An internal cast of a large Virachial valve ; showing the position of the median septum, the elon- gate muscular scars and the absence of plications on the lateral slopes. Chemung group. Tompkins county, N. Y. LlORHYNCHUS Laura, BilHllgS. Figs. 13, 14. Ventral and lioreal views of a rather elongate individual. Fig. 15. Posterior view of the hinge-plate and crura ; showing the great elevation of the latter and their basal expansions. X 4. Fig. 16. The same specimen, viewed from above ; showing the narrow, submarginal dental sockets, the broad triangular divisions of the hinge-plate, the median septum and the recurvature of the long crura. X 4. Fig. 17. The interior of the umbonal portion of the pedicle-valve ; showing the open delthyrium, small teeth and faint muscular impression. Hamilton group. Widder, Ontario. LlORHYNCHUS Kelloggi, Hall. Fig. 18. Cardinal view of an internal cast ; showing the cavities left by the dental plates, median septum and crura. Figs. 19, 20. Dorsal and ventral views of a normal adult ; showing the obsolescence of plications except upon fold and sinus. Hamilton group. Northern Ohio. LlORHYNCHUS QUADRICOSTATUS, VailUXeill. Fig. 21. View of a crushed and somewhat distorted pedicle-valve of large size ; showing the character of the plication Fig. 22. A small internal cast of the brachial valve in which the lateral plications are obsolete. PLATE LU-Contlauecl. LlORHVNOHUS GLOBDLIFOKMIS, VailUXeiU. Vlg. 38. The exterior of the brachial valve ; showing its rotundity, the low, faintly plicated fold and smooth convex lateral slopes. Hamilton group. Otsego county, N. Y. Vig. 34. The exterior of a peiiicle-valve with traces of marginal plications on the sinus. Pig. 35. An internal cast of a more orbicular shell with stronger median plication. Black shale (Genesee shales). Lexington, Indiana. Fig. 3(5. An internal cast of the brachial valve ; showing the extent of the median septum and the form of the adductor scara. Fig. 37. Enlargement of the umbonal portion of an internal cast of the brachial valve ; showing the filling of the dental sockets aud spondylium, the cavities left by the removal of the hinge-plate and thickened median septum. Chemung ()) group. Bromne county, N. Y. LlORHVNCHUS CASTANEUS, Meek. Figs. 38, 39. Profile and doi-sal views of a well preserved individual ; showing the great convexity of the brachial valve, and the exceedingly obscure plication visible only on the median fold. Lower Devonian. Eureka District, Nevada. LlORHYNCHUS ROBU8TU8, sp. 110 V. Figs. 30, 31. Cardinal and ventral views of a very sharply marked internal cast of large size, representing an hitherto undescribed species j showing the muscular impressions of both valves and the vascular sinuses in the pedicle-valve radiating from the impression left by an umbonal testace- ous callosity. Chemung gi-oup. Steuben county, N. T. LiORHYNOHUs Kelloqgi, Hall. Figs. 33, 33. Dorsal and ventral views of an adult shell with more distinct plication than that i-epresented in figures 19, 20. Hamilton group. Northern Ohio. LlORHYNCHUS LeSLEYI, sp. IIOV. Figs. 34-36. Dorsal, ventral and pi-otile views of a mature shell ; showing the I'ather obscurely defined fold on the convex^brachial valves, the deep sinus of the j>edicle-valve, and the unusually complete plication of the lateral slopes. Upper Devonian. Pennsylvania. LlORHYNCHUS Newbekryi, Hall and Wliitfieid. Fig. 37. An internal cast of the brachial valve ; showing the large size of the shell, low median fold, and fine plication. Vig. 88. Cardinal view of an incomplete internal cast of both valves. Upper Devonian. KelloggsviUe, Ohio. m ISi ^ (S ME ® IF (DIE)A Palaeont.N Y.Vol.rvPtU-Vol.vm. RHYXCHOX K Ll.l D.\. (lexvoric llhistrations. Plate LIX RP. Whitfield del Phil.Asl.litK. PLATE LX. (Flpires 1-3, 6-in, 13-48, 51, 53, M^by G..B. Simpson; 4, 5, 11, 12 by E. Kmmons; 49, 50, 53, 55 by R. P. Whitfield.) Subgenus PUGNAX, s.-gen. nov. Page 202. PUGNAX ALTUS, Calvill. Figs. 1-3. Doi-sal, profile and fi'ontal views of an average specimen ; showing the trihedral form and the character of the plication. Middle Devonian. Solmi, lovM. Figs. 4, 5. Frontal and profile views of an individual with highly elevated median fold. Middle Devonian. Hackberry Qrove, Iowa. PuGNAX PUGNUS, Mail ill. Figs. 6, 7. Dorsal and ventral views of an internal cast ; showing the form of the muscular impressions on the two valves. Figs. 8, 9. Front views of two specimens j showing some difference in the elevation of the median fold and, in figure 9, vascular markings on the sinus of the pedicle-valve. Fig. 10. A profile view of the specimen represented in figures 6, 7. Lower Chemung group. High Point, Naples, N. Y. PuGNAX EATONiiiORMis, McChcsiiey. Figs. 11, 12. Front and profile views of the original specimen ; showing the strong but sparsely plicated median fold and sinus and the smooth lateral slopes. Coal MeaAures. Oraysville, Illinois. PuGNAX Grosvenori, Hall. Fig. 13. Ventral view of an average specimen. X 2. Fig. 14. Profile of another specimen ; showing the subtrihedral form. X 2. Figs. 15-17. Front views of three individuals ; showing differences in the size of median fold and sinus and in the number of plications. X 2. St. Louis group. Spergen HUl, Indiana. PUGNAX MUTATUS, Hall, Figs. 18, 19. Dorsal and profile views of an average example. Fig. 20. The interior of an incomplete pedicle-valve ; showing an oi)en delthyrium, small teeth and dental plates. Fig. 21. A portion of the intenor of a brachial valve ; showing the divided hinge-plate. Fig. 22. Front view of the specimen represented in figure 18 ; showing the width and elevation of the fold. St. Louis group. Spergen Hill, Indiana. PuGNAX Ottumwa, White. Figs. 23, 24. Doraal and front views of a normal example ; showing the plication about the margins and the elevation of the median folii. Fig. 25. The interior of a portion of the brachial valve ; showing the broadly divided hinge-plate. X 2. Fig. 26. The intenor of an incomplete pedicle-valve ; showing teeth and dental plates. X 2. St. Louis group. Pella, louM. PuGNAX Swalloviana, Shiiiiiai-el. Figs. 27-29. Dorsal, profile and front views ; showing the contour and character of plication. X 2. Pig. 30. Profile view of an internal cast ; showing vascular sinuses on the brachial valve. X 'i. Figs. 31, 32. Ventral and dorsal views of a smaller shell. X 2. In all of these the absence of plications ovei' the umbunal regions is a notable feature. Upper Coal Measures. Man/iattan, Kansas. PLATE LI— CouUnuwl. PuoNAx MissouRiENSis, Sliunuiid. Fi^ 33, 84. Doi-Mtl aiid profile views of an average example : showiut; tUe IiDeate striation of the Burface. Choteau limestone. Pike county, MistouTi. LlORHYNCHUS (?) BOONENSIS, Sliumiud. Fif . 35. Cardinal view of the biiijfe-plate ; sbuwiiitr itti median divinioii and the elevation of the crura. X 8. Cboteaa limestone. Cooper county, Missouri. ' PuGNAX Greenianus, Ulrich. Figs. 86-38. Front, profile and dorsal views uf an ialeriial ciist of an average individual ; showing' the smooth latei-al slo^tes and faint plication of fold and sinus. Keokuk group. New Albany, Indiana. PuGNAX Uta, Miircou. Figs. 39-41. Doi-sal, profile and front views of an average adult shell. Fig. 42. The interior umbonal portion of the brachial valve ; showing the broad hinge-plate and narrow median incision, X 3. Coal Measures. Manhattan, Kansas. PuGNAX EXPLANATU8, McCliesiiey. Pigs. 43-45. Front, dorsal and profile views, diawn frum a sulphur east of the original specimen. Kaskaskia limestone. Illinois. PuGNAX, sp. ? Figs. 46-48. Profile, front and dorsal views of an undetermined internal cast. The shell has some points of similarity to the Rhynchonella IllinoiseTisis, Meek and Worthen. Coal Measures. Qrdham county, Texas. Genus HYPOTHYRIS, Kixg. I'ajtc lii.i. Hypothyris venostula, Hall (= Rhynchonella cuboides, Soworb}). Figs. 49, 50, 62. Cardinal, frontal and profile views of a typical specimen ; showing the subcuboidal fonn, low median fold and broad, deep median sinus. Pig. 61. Front view of an internal cast with fewer plications, and showing the branches of the vascular trunks on the sinus. Figs. 63, 54. Internal casts of i>edicle-valve8 ; showing the muscular impression, and some variation in the form of the vascular sinuses. Pig. 55. An internal cast of the pedicle-valve, enlarged to show the system of vascular sinuses. X 2. TuUy limestone. Ovid, N. T. IS IIi,^(BSinffiIF (ffilEJv, Paleeont.N.Y.Vol.rv.Pt.ii'Vol.Vffl^ IfHYNCllONKLIinA". OeiU'i'ir lUiislratlons PlateLX G.B.Simpson del Phil.Ast.lith. "Bgi^tm ^"^■■^/^ji »nl;,»t^ PLATE LXI .--..» .-«. ., .. .. ., 3. 3. 3S ., V-':;— ^1\ f-^'/- WH....... . .-,«, .. ., ., ., .,,. 33^ ., I 15. .tlELK , Jl,.i6 by E. Kmmons.) Genu.s CYCLORHINA, gen. nov. Pai^e -.'hi;. Cyclorhina nobilis. Hull. deeply t,uncated beak of the pe.i.cle-valve, straight cardinal line, and low median fold and '" . '■ '^u:"S::::d'^r:;:::r:''"x^3:'^'''-''"^"^"-^ ""-- ^-^^ ^^^^^^^ — >- -^ F.^. 6-9 ProHle, cardinal, frontal and ventral views of a mature individual. f If?- 10 An enlargement of the external surface ; showing the fine concentric lines which crenulate upon the crest of each plication. X 3. Hamilton group. Ttiedford, Oiitarm. Fig. 11. The interior of an incomplete pedicle-valve; .showing the teeth, and the scare of the pedicle, adductor and diductor muscles. Fig. 12. A weathered specimen j showing the cavitie.nia sinoui.aki.s. Viiiiii.voin. Figr. 13. Ventral view of an unusually lai-ge specimen. Figs. 14-16. Cardinal, frontal and profile views of a normal exam]>le. Luwer Helderberg gmuyi (Shaly limestone). Albany county, N. Y. Eatonia peculiauis. Conrad. Fig. 17. Doi-sal view of an average specimen. Lower Helderberg group (Shaly limestone). Albany county, N. Y. Fig. 18. The interior of a brachial valve, viewed in profile from the front; showing the elevation of the cardinal pro<'ess, its lobation and the crura. Fig. 19. An internal cast of the pedicle valve ; showing the impressions of the adductor and diductoi- muscular scai-s and pallial sinuses. X 2. Oriskany sandstone. Albany cownty, N. Y. Fig. 20. The interior uinbonal portion of the brachial valve, enlarged ; showing the elongated lobes of the cardinal process, each of which bears a median groove ; the divergent crural apophyses are attached to the body of the process beneath these lobes. X 3- Oriskany sandstone. CumberlaHd, Maryland. Fig. 21. An internal cast of a brachial valve; showing the impression of the hinge-plate and muscular scai-s. Oriskany sandstone. Albany county, N. Y. Fig. 22. Front marginal view of a specimen ; showing the development of median fold and sinus and the dentate margins. Lower Helderberg group (Shaly limestone). The Helderbergs, N. Y. Figs. 23 24. The interior of brachial valves ; showing the variation in form of the cardinal process. Fig- ure 24 represents an old shell in which the process and socket-walls have become thickened and the parts consolidated. Fig 25. The interior of a pedicle-valve ; showing the open delthyrium, marginal teeth, large diductor scai-s, small adductors with strongly elevated posterior walls; the dentate shell margins and Ungulate extension of the meeilicle-valve \vith imusually large muscular scans. Fig. 34. Ventral view of the specimen represented in figures 29, 30. Fig. 85. An internal cast of an average pedicle-valve. lyower Helderberg group. AVtany and JSclwhar'w oountics, N. Y. Eatonia sinuata, Hull. Fig. 36. A bi-achial valve of average size from which the shell is j)artially exfoliated, exposing the cast of the cardinal process and showing the adductor scars. Fig. 37. An enlargement of the cardinal process viewed from in front ; showing the short crural bases below, and the stout lobes above. X 3. Fig. 38. An internal cast of the brachial valve ; showing the four scare of the adductor muscles. Lower Helderberg gi-oup (originally cited as Oriskany sandstone). Cumberland, Md. 3S lE^CBIlIIIElIP (DIE^ Palaeont.N.Y.Vol rvPtii'Vol.Vni. HHYXCHOX F. I.Lin.V. Cielievi*' lUxistratitms. Plate LXl P. P ^«iitfield del Phil.Ast.hth. I PLATE LXII. (Figures 1-5, 8-10, 14-16, •21-23, 37-45, 52. 53 by E. Emmons ; 7, S, 11-13, 17-20, -24-: ;, 4(!-51 by G. 11. Simpson.) Genus SYNTROPHIA, gen. nov. Page 21B. Syntrophia lateralis, Whitfield. Fig. 1. The exterior of a pedicle-valve ; showing the long, .straight hinge knd broad median sinus. Fig. 2. The exterior of a brachial valve ; showing the broad, obscure median fold. Fig. 3. The exterior of a small pedicle-valve. Fig. 4. A portion of the interior of the pedicle-valve ; showing the cardinal area and spondylium. X 3. Fig. 5. Cardinal view of conjoined valves which have been transvei-sely sectioned in the umbonal region ; showing the sponage in. CaMAKOPHOIUA KHOMBOIDALIS, sp. IIOV. Wig. >B. Dorsal view of a specimen of somewhat btUow the average size. Vig. 86. Frontal view of a similar sjHH-imen enlarffed ; showing' the character of the marginal plication and the development of fold and sini». X 2. ngs 87, 88. 89. Dorsal, vential and front views of an average aiiult shell, possessing a shanier median fold and sinus, stronger plication, and showing the median septum in each valve through the sub- stance of the shell.,' Comiferous limestone. Peru, Indiana. Subgenus PUGNAX, s.-gen. nov. I'age 20-2. PuGNAX (?) Dawsonianus, Davidisoii. Fig. 30. Donwl view of a young shell without plication. X 2. Rgs. 31, 32, 33. Dorsal, profile and front views of a .shell with mature characters ; showing the marginal plication and the elevation of the beak. X 2. Carboniferoiw limestone. Windsor, Nova Scotia. Genus CAMAROPHORIA, King. Page 21S. CAMAROPHORrA SUBCUNEATA, Hilll. Fig. 34. Dorsal \-iew of a young, but freely plicated shell ; showing the shallow valves, subtriangular out- line, and long cardinal slopes. Figs 3f), 36. Protile and fi-ont views of a mature and gibbous shell, showing the character of the plication and the broad, concave canlinal slopes. Kg. 37. A portion of the interior of the pedicle-valve, showing the spondylium sui)poi-ted by a median septum. The summits of the teeth have been broken, showing their lateral union with the walls of the shell. X 2. St. Louis group. Waxtmigton cdunty, Indiana. CAMAKorHouiA suBTKiGoNA, Mock .iikI Woitlieii. Pig*. 88, 39, 40. Cardinal, frontal and ventral views of an internal cast; showing the contour of the shell, the denticulate margin of the valves on the broad cardinal slopes, the sharjily serrate anteiior and lateral margins and the (ravity left by the spondylium and median septum of the pedicle-valve. Chert of the Burlington limestone. Burlingtiin, lovxi. Figs. 41, 43. Internal casts of pedicle-valve.s showing the form of the muscular impression. Keokuk group. Nauvoi), lllinm^. Fig. 43. The umbonal jwrtion of an internal ca.st of both valve.s, enlarged, the pedicle-\alve being above. This figure shows the cavity of the spondylium, median septum and oblique dental plates of the pedicle-valve ; median septum and small umbonal spondylium of the brachial valve. X 3. Chert of the Burlington limestone. Pike county, Missouri. Subgenus PUGNAX, 8.-gkn. nov. •Page 2(W. PuoNAX Missouri ENsrs, Swallow. Figs. 44. 45. Cardinal and profile views of an internal cast of a large specimen ; showing the contour of the shell, the cavities of the median septunj of the bratthial valve, the dental platOK ami the fore- »hortenerachia! valve in which the filling of the spondylium is exposed and the four scars of the adductor impression lication. Niagara ultmUe, Kentucky. CONCHIDIUM MULTICOSTATUM, Hall. Fig. 6. Doisal view of an internal cast ; showing the fine plication about the margins. Niagara group. Waukesha, Wisconsin. CONCHIDIUM LiTTONI, HuU. Figs. 9, 10. Dorsal and profile views of an average specimen ; showing the abundant plication of the sur- face and the characteristic breadth of the valves in the umbonal region. Niagara group. Hardin county, Tennessee, CONCHIDIUM Knappi, Hall and Whitfield. PigK. 11, 12, 13. Profile, dorsal and cardinal views of the oi-iginal specimen ; showing the contour and du- plicate plication of the valves. Niagara group. Near Louisville, Kentucky. CONCHIDIUM Knighti, Sowei'by. Fig. 14. Longitudinal section of the valve-s ; .showing the development of the spondylia and median septa. The specimen is so broken as to exhibit the proximal wall of the spondylium of the pedicle- valve an$hritpskire. P!g». 15,16. Dorsal and profile views of an averafje typical example; showing the contour of the species, consjiicuoufl and incurved umbo of the pedicle valve, and the complete plication of the surface. Amestry limestone. Aymeslry, UnglaTid. (Figures 14-16 after Daviijion.) Palaeont.NY.Vol.IYPt.ii-Vol.vni. 113 Ili.^(BmS®IP (ffiim^ PENTAMERIDA Creixeric' Tlhistrations. PlateLXiV R-P.Whitiielddei PhiLAs tilth. h PLATE LXV. (Kifrures 1-3, S^by G. B. Simpson ; 4, 6-9 by K. Kmhonb.) Genus CONCHIDIUM, Linn^. I'age 'J31. CoNCHiDiUM DECUSSATUM, Whitcaves. ¥ig. 1. Ventral view of a sjiecinien partially exfoliated in the umbonal region ; showing the fine, dupli- cate plication and the delicate concentric lineation of the surface. Vig. "i. Dorsal view of the umbonal jiortion of an internal cast ; showing the cavity of the spondylium and median se])tum of the pedicle-valve, and the genital markings atjout Ihe beak. Niagara group. O^rand Rapids of the Saskatcheioan River, Britwh Ainenca. C0NCHIDIU.M LAQUEATUM, Coiiiiid (=Pentameru8 NOBiLis, Eminoiis). Fig. 3. An anterior view of a jwrtion of the interior, looking into the chamber produced by the union of the sjiondyliuin and septal plates ; showing the curvature of the latter, their explanate upper surfaces, and the foreshortened crural apophyses. Pig. .■>. Another \new of the same specimen ; showing the spondylium with a portion of the median sep- tum adhering, and the extent of the septal plates and crural processes. FigB. 4, 6, 9. Dorsal, ventral and profile views of an internal cast of a rather narrow shell ; showing the contour, character of the plication and smooth umbonal slopes. Pig. 7. Longitudinal section of conjoined valves ; showing the extent of the median septum of the pedicle- valve (juite to the anterior margin of the valve, its concave anteiior edge, the projecting ex- tremity of the spondylium, and in the brachial valve, the relatively short spondylium and septa, and the projection of the crural apophyses. Kg. 8. An internal cast of a brachial valve which i-etaines the prevailing broader form of the species. Niagara dolomites. Delphi, Indiana. m 33.=^CE31I5I®IF ©m^ Palaeont. N Y.Vol.rv.Pt.ii= Vol.vm. I'EXTAMEHIDA. C'eiiei'it" IlIiistrHtitiUs. Plate LXV EEmmons del . Phil.AstUth. PLATE LXVI. (Figures 1-5, 11, 13, 14, 1«-1H, -ii-irt by E. Emmons ; H, s, 10 by K. P. Whitkield ; 7, '.t by F. S. Swinton ; 12, 20-22 by U. B. Simpson.) Genus CONCHIDIUM, Linne. Page 231. CONCHIDIUM UNGUIFORMIS, Ulricll. Figs. 1-3. Doi'sal, cardinal and ventral views of the original specimen ; showing the form of the shell, the character of its [plication, its concentric varices and tine growth-lines. The drawings ai-e slightly restored in the umbonal region of the pedicle-valve. Pig. 4. A lateral view of the same specimen, in which the median septum and spondylium of the pedicle- valve are exposed. Niagara group. Near Loui.iville, Kentucky. CONCHIDIUM, sp. iiidet. Fig. 5. An internal cast of a small pedicle-valve, with a coarsely plicated surface ; showing the apical portion of the tilling of the spondylium and a somewhat distorted median septum. Niagara dolomites. Near MiliDaukee, Wisconsin. CONCHIDIUM EXPONENS, Sp. IIOV. Figs. 6-9. Interioi-s of i>edicle (figs, 6, 7) and brachial (tigs. 8, 9) valves of a strongly costate shell ; showing the structure of the interior. Niagara group (Halysites bed). LouistiUe, Kentucky. CONCHIDIUM MULTICOSTATUM, Hall. See Plate 64. Fig. 10. A profile of the original specimen, an internal cast. Niagara dolomites. Wamcaiitosa, Wisconsin. CONCHIDIUM BILOCULARE, LilUlC. Fig. 1 1 . Dorsal view of an average example ; showing the form of the shell, character of the surface, afld retaining a portion of the deltidium. Fig. 12. A profile of the same specimen ; showing the long, concave and smooth cardinal slopes. Fig. 13. A natural longitudinal section of conjoined valves; showing the relation of the spondylium and septal plates. Fig. 14. Ventral view of the same individual ; showing the length of the median septum. Upper Silurian limestone. Island of ffotland. CONCHIDIUM DECUSSATUM, WhitcaVCS. See Plate 65, tigs. 1. 2. Fig 15. Dorsal view of a small example ; showing the form and exterior characters of the species. Niagara dolomites. Rapids of the t^a^katchewan River, British Ainerica. CONCHIDIUM CoLLETTi, Miller. Figs 16, 17. Ventral and profile views of a pedicle-valve ; showing the tine plication, frequent imbricating growth-varices, and the expanded anterior margin. Niagara limestone. Indiana. CONCHIDIUM GEORGIJi, sp. llOV. Figs. 18, 19. Dorsal and cardinal views of the brachial valve ; showing the conspicuous median fold and the plication of the surface. Clinton group. Trenton, Georgia. PLATE LXVI— Contlnoed. CoNCHiDiuM Gkeenii, sp. nov. Piga. 30-23. Profile, cardinal and ventral views of a 8i)ecimen somewhat restored about the margins ; showing the short, ventricose valves and fine, duplicate plication. Niagara dolomites. Near Mihoaukee, Wisconsin. CoNCHIDIUM, sp. Kg. 38. An internal cast of the pedicle-valve of a probably undescribed species j shovring the character of the plication and the length of the median septum. Niagara dolomities. Hawthorne, Illinois. CONOHIDIUM CRASSIPLICA, Sp. IIOV. Figs. 34, 26. Dorsal and j>rotile views ; showing the ovate form of the shell, the subequally convex valves, short and depressed beak of the pedicle- valve and the coarse, duplicate plication of the snrfkce. Niagara group. Probably frmn the xAcinity of Louisville, Kentucky. m 33.^(B3I3ffiIP ®]El^ PalaeontN T.VoirVPt.ii'Vol.Vm. FENTAMERIDiS. OoiuTK' Ilhistrations. PlateLXA/^ £ Gmmons del Phil.AsiliUi. PLATE LXVII G™ CONCHIDIUM, Lxn^,. P^ge 231. " "r"""'"" "taw .„«•„..., , °"~'" °' Pl.»«o™ ,v.r H. -■ 'i" r4'tti:::srrs - """ '" '"^" '""•"« — -« Fig. Figr. t'uelph dolomites, ffalt, Onta,-io. ^^- 6, 7. Dorsal and t , ^''''''"''''^^ SCOPARIUM, sp. „ov. the species a Jp\U~:,^-!^^^^ she,,. sHo.in, .he o„t,i„e of Guelph dolonutes. Ife^w, 0,.torto "' *''"''*'°"- Fics 8 q V . ■ . t:ONCHIDIUM OBSOLETUM, SI). Iiov *'««. 8, 9. Ventral and doreal views of an internal cast of a «^ Genus PENTAMERUS, Sowerby. Page 23«. Kit 10 A VI. , . """""""■ ■•'"oiBBostre, Hull .„d Whilfleld P,S 15. P„.l, „.» ., . „„,,„ ,„,.„„„ ,„, , ,^ ,^. _^^^ ^^ Ni.,^™ ,|olo,.ite., »-«..■ ifO„rt„. B-tom,,, • "PM... "'^ '" ''';S:anff::^rtLrdir:^ wMch^howswIt,. ^ue^ disti„ctne. tKe posi. Chert of the Niagara group. PVuconMn. Fig. 17. Profile of a small and gibbous internal cast, having somewhat the form of the P oblo,iam var MaqiMketa (see figs. 11-13), but less regularly convex. ' Figs. 18, 19. Cardinal views of internal casts; showing the variation in the convexity of the valves and the position of the internal apophyses Niagara dolomites. JYear Milwaukee, WuconMn. PLATE LXVII— Continued. Pentamerus OBLONOU8, vjir. Maquokbta, var. iiov. Figs. 11, 13. Dorsal and profile views of an internal cast of a chm-acteristic example ; showing the ovoid anil regularly convex valves. Fi^. 13. A cardinal view of another individaal ; showing the position and extent of the internal plates. Niagara dolomites. Near Jhil/uque, Iowa. Pentamerus oblongus, Soweihy. Fig. 30. The interior of the umbonal portion of a silicified shell ; showing the spondylium and median septum. Niagara dolomites. HUlsboro, Ohio. i m ^JiJv.©3I2©IP (Dlffi^ Palaeont N YVoirVPtii-VolVra. PKNTAMERin/L ("Tei\<»i'ic lUustrjJtions. Plate LXVII, ^ B.Simp.icii del J ilu.r.Sl.iiUL. PLATE LXVIII. (FiKaro8 l-« by E. EMHOM8.) Gends PENTAMERUS, Sowerby. Page 236. Pentamerus OBLONGU8, Sowerbv. FigB. 1, 2. Dorsal \-iew8 of two shells ; showinjr the variation in outline assumed by the species at this local- ity. Figf. 1 (see also plate Ixix, fig'. 7) approaches the subquadrate outline of P. ohlongus, var. gubrectus (see tip- 6 and plate Ixix, figfs. 8-10), but has less conspicuous urabones and less con- vex valves; fig. 2 has a peculiarly triangular outline, which is reproduced with a strongly trilobate anterior margin in the larger specimens from Yellow Springs, Ohio (see figs. 3-5). Clinton group. Rochester, New York. Fly. 8. Dorsal \-iew of a large, elongate shell, with a broad median lobe. Fly. 4. Ventral view of another specimen of similar character, the two lateral grooves defining the median and U.teral lobes being very strong. The specimen shows the cavity of a very short median septum. Pig. 6. Dorsal view of a smaller specimen, less distinctly trilobed, but with the umbo of the pedicle-valve very broad, though slightly imperfect at the apex. (Compare in this respect plate Ixix, fig. 8.) The lateral undulations on the brachial valve are actually very faint and have been made mach too conspicuous in the figure. Niagara dolomites. Yellow Springs, Ohio. Pentamerus oblongus, var. subrectus. var. uov. See Plate Ixix. Pig. 6. Dorsal view of a large individual of this variety slightly impeifect at the anterior margin ; show- ing the subquadrate outline, medially convex and bro.idly lobed valves. Niagara beds. JoTies county, Iowa. Pentamerus oblongus, var. cylindricus, Hall and Whitfield. Pigs. 7, 8. Dorsal and ventral views of a characteristic example of this variety ; showing the extremely elongate-elliptical outline and broadly trilobed exterior. Niagara dolomites. Utica, Indiana. Palaeont.N.Y.Vo!.IV.Pt.n=Vol.Vin. 113 ni^cesiHmip ©10^ PANTAMERIDJS. Oexveric lUustrations. Plate LXYIII E Emmons del Phil.Asthth. PLATE LXIX. (Fimirea 1-10, IS by G. B. SiMrgON; 11, 1» by K. P. Whitfield. ) Genus PENTAMERUS, Sowerby. Page 236. Pentamerus OBLONGU8, Sowerby. fig. 1. Doroal view of an internal cast of a small shell, broadly trilobed and having a similar outline to youn^ forms of the variety subrectus (see tig-s. 2, 3) though with much shallower valves. Niagara dolomites. Richmond, Indiana. Pentamerus oblongus, var. subrectus, van iiov. tiee Plate t>8. Figs. 2, 3. Dorsal and ventral views of a small specimen of subquadrate outline, trilobed exterior, and showing the single median septum in both valves. Figs. 8-10. Dorsal, pn>file and ventral view.s of a noi-mal matui"e individual ; showing the characteristic subquadrate outline, prominent umbo of the pedicle-valve, trilobate exterior, and linear median depression on both valves. Niagara beds. Castle Orove tovmship, Jones county, Iowa. Pe.\tamerus oblongus, Sowerb}'. Figs. 4, 6. Dorsal and venti-al views of a small elongate internal cast in chert, similar in contour and size to a form occurring at Utica, Indiana, in association with the variety cylindrlcus. This shell occurs in the chert of the Maquoketa region near Dubuque, Iowa, but not in immediate asso- ciation with the var. subrectus. Niagara beds. Jones county, Iowa. Fig. 6. Dorsal view of the umbonal region of an interaal cast in chei-t ; showing the cavities left by the septum and septal plates, the deltidium and the lateral divisions of the hinge-plate. X 2. Niagai-a beds. Monmouth, Iowa. Fig. 7. Ventral \-iew of a subquadrate shell with the lobation of the surface distinctly defined. The dor- sal view of this specimen is given upon plate Ixviii, fig. 1. Clinton group. Rochester, New York. Pentamerus oblongus, van cylindricus, Hall and Whitfield. FlgB. 11, 12. Profile and dorsal views of the original specimen of this variety ; showing the elongate form and a faint trilobation of the exterior. Niagara group. Near Louisville, Kentucky. Pentamerus oblongus, Sowerby. Pig. 13. Dorsal view of an internal cast of a large and evenly convex shell having the ovoid form and regular contour of the var. Maquoketa (see plate Ixvii, figs. 11-13), which, however, is a per- sistently smaller form. Niagara dolomites. Locality uncertain ; probably Northern Indiana. Pig. 14. An outline sketch of a large brachial valve having the broadly ovate form and trilobed exterior of the specimens from Yellow Springs, Ohio, represented on plate Ixviii, figs. 3-6. Niagara dolomites. Proltahly from the vicinity of Richmond, Indiana. Palaeont. N.Y.Vol.nrPt ii- Vol.vm. 113 iBJs.(eiiiii©ip (sm^ PENTAMERIDiS. ("loiieric Illustrations Plate LXIX E.Emmons de! Phil.Ast.lith. PLATE LXX. (ngurag 1, i, 4-14 by K. Emhons ; 3, copy.) Genus PENTAMERUS, Sowerby. I'age 436. Pentamerus oblongus, Sowerby. See plates Ixviii, Ixix. Vif. 1. Dorsal view of an internal cast of a broadly ovate shell, with evenly convex valves. Niagara dolomites. Near Milwaukee, Wisconsin. Pig. 2. A natural lonjfitudinal section throug'h both valves ; showing the comparatively short median sep- tum and septal plates, the projecting spondylium and crural processes. Clinton irroup. Rochestifr, New York. Fig. 3. A copy of the original figure of this species given by Mdrchisom in " Silurian System," plate xix, figure 10. Fig. 4. Dorsal view of a large, elongate-.«ubovate shell, with trilobed surface, broadly shouldered urn- bones and closely incurved and depressed ventral beak. Clinton group. Rochester, New York. Pentamerus oblongus, vnr. subrectus, var. uov. See plates Izviii, Ixix. Fig. 6. A somewhat weathered specimen in which the valves have been displaced from their normal posi- tion, exposing the spondylium of the pedicle-valve, and, by the removal of the rock, also show- ing a part of the united septal plates of the brachial valve. This spondylioid condition of these plates is a normal feature of this variety. Niagara beds. Jones county, Iowa. Genus CAPP^LLINIA, gen. nov. Page 248. Capellinia mira, sp. IIOV. Figs. 6, 7. Ventral and cardinal views of an average specimen ; showing the predominant convexity of the brachial valve, the smooth sui-fa(;e and the position and extent of the internal plates. Fig. 8. Cardinal view of another example in which the convexity and umbonal incurvature of the brachial valve are still more conspicuously developed. Fig. 9. Cardinal view of a i>edicle-valve ; showing the inconspicuous, suberect beak and wide delthyrium. Fig. 10. Ventral view of the same specimen ; showing the length of the median septum. Fig. 11. Profile view of a normal individual ; .showing the relations of the valves. FigK. 12, 13. Ventral and profile views of anotner example in which the umbo of the pedicle-valve is ab- ruptly depressed. Fig. 14. A brachial valve, showing the length of the septal plates and a low radial plication over the um- bonal region. Niagara dolomites. Near Milwaukee, Wisconsin. m m^CEiirn©iP ;Eiiffi^ Palaeont.N-Y.Vol.rv.Ptii-Vol.vm. PENTAMERinJt PlateLXX EEmmnns del. FhilAst Uth.. PLATE LXXI. (Figures 1-3 copies ; 4, 5, 24-33 by K F. Whitfield ; (!-10, U-16, 34-38 by G. B. Simpson ; 11-13, 17-23 by E. Emmons). Genus BARRANDELLA, gen. nov. Page 241. Barrandella linguifera, Sowerby. Figs. 1, 2. Doi-sal and profile views of a normal individual ; showing- the chara*;ter of the exterior and the well defined median fold on the brachial valve. Pig. 3. A longitudinal median section of the valves ; showing the .small spondylium and extremely short median septum of the pedicle-valve, and one of the septal plates of the brachial valve. Wenlock limestone. Dudley, England. (Figures 1-3 after Davidson ) Bakrandella ventricosa, Hall. Figs. 4, 5. Front and doi-sal views of a typical example ; showing the fold upon the brachial valve, its faint plication, and the cavities of the median septa. Niagara dolomites. Waukesha, Wiscmisin. Pigs. 6, 7. Ventral and profile views of a ventricose specimen with a low sinus on the pedicle-valve. Pigs. 8-10. Dorsal, profile and front views of a smaller individual having the fold and sinus distinctly • plicate. Niagara dolomites. Near Milwaukee, WiscoTisin. Barrandella fornicata, Hall. Figs. 11-13. Profile, doi-sal and ventral views of the exterior of a specimen of average size ; showing the median folortion of conjoined valves ; showinjf, above, the free spondylium of the i)e!ates of the deltidium and coiu-se, irregularly duplicate plication of the surface. Figs. 31, 33. Dorsal and profile views of a large sjxjcimen with a finer and more regular surface plication, more conspicuous an^tr."itiortion of the brachial valve j showing the septal plates, the four sharply defined scare of the adductor muscles, the va.<«;ular sinuses and genital markings. Comiferous limestone. Westeiii New York. Fig. 6. The exterior of a brachial valve having the characteristic subovate outline. Figs. 7, 9. Dorsal and profile views of a shell of full medium size with gibbous valves and finely striated surface. Comiferous limestone. Cayuga, Ontario, Fig. 8. Internal cast of a large brachial valve ; showing the muscular impi-ession and the cavity left by the removal of the hinge-plate. Comiferous limestone. Le Roy, New York. 113 mj^.CBSI2®IP®Ic)^ Palaeont.N.Y.Vol.rv.Pt.n=Vol.vm. AMPHIGENUDA-. ('•OTxerir Illustrations Plate L XXIV aP.Whitfield del Ehil.Astlith. PLATE LXXV. (Tigures 1-6 by G. B. Simpson; 7. 9 by F. B. Heek; 9 by E. Emmons.) Genus RENSSEL^RIA, Hall. Pace 26S. RBNSSELiGRIA CaTUOA, Sp. IIOV. FIcB. 1, 2. Dorsal and ventral views of a specimen which retains most of the shell ; showing the fine sur- face plication and the lenticular form of the valves. Oriskany sandstone. Cayuga, Ontario, Ren88el.«;ria ovulum, sp. nov. ¥\g. 3. An internal cast of the brachial valve ; showing the muscular scars, the large cavity left by the hinge-plate, and the genital markings in the umbonal region. Fig. 4. An internal cast of the pedicle-valve ; showing the filling of the deep muscular cavity and its division by the diductor and adductor scars, and the cavities left by the teeth. This species differs from the foregoing in is persistently greater size, much more convex valves, and coarser plication of the surface. It is a more orbicular and moi-e i-egularly convex shell than R. ovoides. Oriskany sandstone. Cayuga, Ontario. RENL8EL.ffiRIA OVOIDES, EatOll. Tig. 6. An internal cast of the brachial valve ; showing the cavity of the hinge-plate, the branching vascular sinuses in the umbonal region and the anterior and po.sterior division.^ of the adductor muscular impression, the surface of the posterior scars being strongly marked with ramifying lines. The structure and arrangement of all of these parts is strikingly similar to that occur- ring in Amphigenia (see plate Ixxiv, fig 5). Oriskany sandstone. Sclwharie, New York. Pig. 6. An internal cast of a pedicle-valve having a regularly oval outline, and showing the filling of the muscular impression and the cavities left by the teeth. Oriskany sandstone, ^irnngport, Cayuga couvty. New York. Fig. 7. The exterior of a pedicle-valve, having the characteristic inflexion of the lateral margins ante- riorly, anil showing the fine surface plication. Fig. 8. Profile of conjoined valves ; showing the usual convexity of the species. The shell of the brachial valve has been exfoliated, losing its surface plicjition. Oriskany sandstone. The Helderhergs, New York. Pig. 9. A brachial valve which is broadly flattened in the umbonal region and greatly narrowed anteriorly. The shell has been lost except about the umbo, exposing a portion of the muscular Bears. Oriskany sandstone. Knox, New York. 113 ISi^lSSIindllF (DIE)^ Palaeont.N.Y.Vol.IYPtii'Vol.VIII. RENSSELAEHIDJt (~'ei\erir Illustrations Plate LX XV G B.aimpiicir. del Phil.Ast.lilh.- PLATE LXXVI. (Figures l-3a, 9, il-'U by B. P. Whitfield; 4-7. 20 bv E. Kmmons; 8, 11-16, 17, 2S-28 by F. B. Mkek; 10, 16, 18, 19 by G. B Simpson.) Genus RENSSEL^RIA, Hall. Page 2.54. Renssel^kia mutabilis, Hall. Figs. 1, 2. Doi-sal and profile views of a rather larg'e and somewhat elongate shell. Fig. 3. An outline sketch showing the loop and its relative length. Fig. 3a. The loop enlarged to show its form in more detail, the elongate triangular expansion formed by the union of the descending lamellfe, and the median ridge along the line of coalescence of these j)art8. produced upwardly and posteriorly into a free extremity. Lower Helderberg group. Becraft's Mountain, Columbia county, JS^eio Ycrrh. Genus TRIGERIA. Bayle. Page 285. Trigeria Portlandica, Billings. Figs. 4, 5. Doi-sal and ventral views of the original specimen of Rensselaeria Portlandica, Billings, which is tentatively referred to the Genus Triqeria. Lower Helderberg gi-oup. Square Lake, Maine. Trigeria Gaudryi, OElilert. Figs. 6, 7. Dorsal and profile views of an intei'nal cast, jirovisionally referred to this species ; showing- the form of the shell, the fine and simple plication of the exterior and the cavities left by the removal of the dental pla'es in the pedicle valve and the median septum in the bi'achial valve. In fig 7 the convexity of the \alves is not satisfactorily represented, the brachial valve being too convex and the opjKisite valve not convex enough. Oriskany sandstone. Camherland, Maryland. Genus RENSSEL^RIA, Hall. Page 254. Renssel^eria Marylandica, Hall. Fig. 8. Enlartped view of the cardinal portion of the pedicle-valve ; showing the foramen and deltidial plates. ¥\g. 10. Dorsal view of a typical exterior ; showing the fine surface plication and the oval outline of the valves. Fig. 11. Dorsal view of another individual, less sharply plicated and having a less convex brachial valve. Fig. 12. The interior of a neai-ly complete pedicle-valve ; showing the deep and strong dental lamella; resting upon, though not consolidated with the bottom of the valve, and the elongate muscular impressions. Fig. 13. Longitudinal section of the valves ; showing the loop in profile, its anterior extension and the ele- vation of the crural apophyses ; also the depth of the dental plates in the pedicle-valve and the umbonal thickening of the shell. Fig. 14. The interior of the brachial valve ; sHowing the medially divided hinge-plate and the loop with its long, acutely triangular anterior plate and median ridge with its short and free posterior extension. Fig. 15. Profile of the specimen represented in tig. 11 ; showing the convexity of the valves. Fig. 17. The cardinal portion of the brachial valve ; showing the form of the hinge-plate, the obsolete vis- ceral foramen, and the anteinor median division. Fig. 19. The interior of the umbonal portion of a brachial valve of an old shell in which the hinge-plate is much thickened. The specimen is projected backward to show the inner extremity of the PLATE UXVI-CoDtiDued. visceral canal, the outer opening being visible at the apex of the plate. This canal is, how- ever, closed by testaceous deposit, and the median division of the plate on its upper surface largely obscured from the same cause. Fig. 90. The interior of the umbonal portion of the pedicle-valve ; showing the dental plates and muscular impressions. Oriskany sandstone. Onmberland, MaryJand. Genus AMPHIGENIA, Hall. Page 252. Ahfhioenia elongata, Hall. See Plates 73, 74. Fig. 9. The cardinal portion of the brachial valve ; showing the form of the hinge-plate, its median depression, the opening of the visceral foramen, a portion of the septal plates and the branch- ing vascular sinuses. Comiferous limestone. Le Boy, New York. Genus RENSSEL^RIA, Hall. Page 254. Renssel^ria ovoides, Eaton. See Plate 75. Fig. 16. The hinge-plate enlarged ; showing its form, the opening of the visceral canal, the highly developed crural plates ; also the elongate dental sockets and outer socket walls. X 2. Fig. 18. A cast of the hinge-plate ; showing the unbroken filling of the visceral canal. Oriskany sandstone. The Helderbergs, New York. Renssel^ria mutabilis, Hall. See tigTires l-3a. Pigc. 21, 23. Dorsal and profile views of a broad, ovate form with elevated umbo, open delthyrium, well- defined cardinal slopes and rather coarse surface plication. Ix>wer Helderberg group. Becraft's Monmtain, Columbia county. New York. Rensseljeria ^quiradlata, Conrad. _ Figs. 23, 24, 2.5. Dorsal, profile and front views of one of the original specimens ; showing the form of the shell and the character of its plication. Lower Helderberg group (Upper Pentamerus limestone). Schoharie, New York. Rens8ela;ria elliptica, Hall. Figs. 36, 27, 28. Dorsal, profile and front views of the original specimen ; showing the foi-m and convexity of the shell. Lower Helderberg group (Shaly limestone). Schoharie, New York. IS iB,=^©minii)iP ©n]^ HKNSSZLiVEHlD.sE. Palaeont.N.Y.Vol.rv.Ptii'Vol.vm. Creiu^rir lUiistr/itu Plate LXXVI RP. Whitfield del Phil.AsUith. PLATE LXXVII. (Figures 1-9, 2S-2n by K. B. Meek ; 10, 11, 17-2i by G. B. Simpson ; 12-14 by R. P. Whitfield ; 26-28 by F. J. Swinton.) Subgenus BP^ACHIA, s.-gen. nov. Page 260. Beachia Suessana, Hall. Fig. 1. The interiore of two pedicle-valves, the upper retaining the deltiilial plates, the lower having lost the?e ) lates, but showing the dental lamellae. Both tigures show an obscure muscular area divided by a low median ridge. Fig. 2. The interior of a brachial Valve ; showing the hinge-plate, medially depressed and perforated at its apex by the viscei'al foramen, the (iental sockets, and the form of the loop with the median rod-like process extending backwaiil and upward from the anterior plate. Fig 3. Front view of conjoined valves ; showing the tine plication of the surface and the inflexion of the lateral margins. Fig. 4. Median longitudinal section of conjoined valves; showing in profile the loop with its long, erect crural apophyses, the elevation and direction of the median process extending backward from the anterior plate. Fig. f). Views of the interior of two brachial valves ; showing the inflected lateral margins and some vari- ation in the comlition of the hinge plate. Figs. 6, 7, 9 Ventral, profile and doreal views of a typical example ; showing the outline, contour and plication of the valv(>s and their lateral marginal inflexion. Fig. 8. Profile of a smaller shcl!, with the marginal inflexion of the valves extending to the anterior ex- tremity. Figs. 10, 11. Views of the hinge-plate in two individuals ; showing differences due to age and consequent thickening of the parts. X 2. Oriskany sandstone. Owtiiherland, Maryland. Genus MEGALANTEKIS, Suess. Page '277. Megalanteris ovalis, Hall. Fig. 12. An internal cast of the pedicle-valve ; showing the filling of the deep scar of the diductor muscles, enclosing the small subcordate atlductor scar, with traces of vascular sinuses and genital markings. Fig. 13. The doi-sal side of an internal cast ; showing the deep impression of the prominent hinge-plate and cardinal process, and the adductor muscular seal's. Fig. 14. A similar view of another specimen to which a portion of the pedicle-valve adheres ; showing the cavity of the hinge-plate and the division of the muscular area into anterior and posterior scars. Oi-iakany sandstone, f^choharie, New Turk. Fig. 15. The ventral side of another internal cast ; showing the impressions of the muscular scars and vas- cular sinuses. Fig. IB. Doi-sal view of the same specimen ; shiwing the deep cavities left by the grooved cardinal pro- ce.SH, crural bases, and adductor scars. Figs. 17, 18. Posterior and interior views of the cardinal portion of the brachial valve, enlarged; showing the hinge-plate and the stout, erect, biloVied and deeply grooved cardinal process, the broad crural ba-ses, and a portion of the muscular impression. X 2. Figa. 19, 20, 21. Interior, profile and fnmt views of a gutta-percha impression taken from a natural cast of the interior, having 9, very highly developed cardinal process divided on its posterior face by a single median groove ; showing also the crural bases and muscular area divided by a low median septum. Fig. 22. The umbonal portion of the brachial valve, drawn Jrom a gutta-percha impression taken from the specimen repre.sented in fig. 16. The two grooves on the posterior face of the cardinal process are charactei-ized by series of tine, diverging lines. Oriskany sandstone. Albany county. New York. PLATE LXXVII— Continued. Genus RENSSEL^RIA, Hall. Pa^ 254. ReNSSEL^ERIA CuMBERLANDIiE, Hall. FifC8. 23-25. Doi-sal, profile and ventral views of one of the original specimens j showing the form and pro- portions of the shell, the marginal plication of the surface, the deltiilial plates and sharply de- fine> ^' B^iM''s<»: in-lf.by K. P. \Vhitfiei.d.) Genus NEWBEKKIA, Hall. ratre 261. Newbekria Clayiolii, Hall. K«f. I. An internal cast of a ^lortion of the peedicle-valve of a small individual. Pigs. 15, 16. Dorsal and protile views of a similar specimen ; showing the convexity of the valVes. Hamilton gi-oup. WaterUm, lotca. Newberria Litvis (Meek Jsp.), Whiteaves. Figs. 17, 18. Dorsal and ventral views of an internal (!ast of a very large anei-fectly retained Fig 24. Dorsal view of a large internal cast ; showing a portion of the base of the muscular platform, and divergent, probably vascular impressions over the adjoining surface. Figs 25, 26. Pi-ofile and dorsal views of a characteristic and somewhat gibbous example. St. Louis group. DlELASMA ROWLEVI, WoHllCU. Figs. 27, 28. Profile and doi-sal views of an internal c-ast, referred with hesitation to this species; showing the muscular platform of the bra<;hial valve, and the cavities of the dental lamellae. Choteau limestone. Orai/dtm Uprings, Mixsi/uri. DlELASMA BOV1DEN8, Moitoil Figs. 29, 30. Dorsal and pi-ofite views of a rather gibbous sjiecimen ; showing the contour of the valves and the oblicjue foramen The coraal, profile and ventral views of the shell ; showing the convexity of the valves and the eokrae plication. Lower Helderberg group. Perry oounty, Tennessee. ScBOBNUS HOiMCEOSPIRA, s.-gen. nov. Page 112. See PlaW .50. HOM(EOSPIRA APRINIFORMIS, Hall. FTgB. 34. 38. Dorsal and profile views ; showing the contour and character of plication. Niagara group. Ciiinberlarid, Maryland. Genus EUMETRIA, Hall. Page 116. See Plate 51. Eumetria Verneuiliana, Hall. Pigs. 36, 37. Dorsal and profile views of a large, sharply costate individual. St. Louis limestone. Spergen Hill, Indiana. Genus PTYCHOSPIRA, gen. nov. Page 112. See Plate ."iO. Ptychospira sex-plicata, White and Whitfield. Fig. 88. The exterior of a pedicle-valve of the type specimen. Kinderhook group. Burlington, Lnoa. Genus ZYGOSPIRA, Hall. Page IM. Se« Plate 54. Zygospira PUTILLA, sp. IIOV. Pigs. 39, 30. Dorsal and ventral views of a typical example. Hudson River group. IHke county, Missouri. Genus RHYNCHOTREMA, Hall. Page 1»2. See Plate ati. Rhynchotrema c^pax, Coiuiid. Kg. 81. Cardinal view of the pedicle-valve shown on plate 56, fig. 17 ; showing the excavation of the pedicle-paasage and its opening through the substance of the shell. X 3. Hudson Rivei- group. Iron Ridge, Wisconsin. Genus GLASSIA, Davidson. Page l.">2. Glassia Rominoeri, .sp. uov. Kig. 32. A preparation showing the inti-overted coils and the direction of the loop. X 3. Figs. 33-35. Dorsal, profile and ventral views of a specimen, showing the smooth exterior and biloberior of a i>eilicle-valve; showinjr the siiiall sjtomly limn made by the union of the short rt Can/tin, Veniumt. ORTHOTROPIA, okn. nov. ORTHOTROriA DOLOMITICA, 6\). IIOV. Fi(j. 3. Ventral view of an internal cast, nat II I'lil t^izo ; showinji' the fonn of the shell, the short, straigfht hing«, and the conspicuous mus(Milar si'nrs. Pig'. 4. The interior of a jiedicle-valve ; showinjr the cawlinal are*, open ilelthyrium, muscular scar and short raeiiian septum. V\ga. 6-7. Ventral, dorsal and caniinal views (the last with the peilicle-valve ahove) of an internal cast; showing the fonn of the muwHilar impi-essions, the median septum in ea<;h \alve, and the ele- vation of the carilinal area, X 2. The external surface of the shell is vinknown. Niagrara dolomites. Near Milimukee. M'iscongin. The generic charactei'S of this shell ai-e so distinctly unlike those of any existing genus that it is here proposed to distinguish it by the new tei-m Orthotropia. Orthi.s ? OLYPTA (C(H)ipare 0. Loieni, Liiulstioni), sp. iiov. Fig. S. A jiartial internal cast of the pedicle-valve ; showing the outline of the shell, its surface ornamenta- tion and the fomi of the muscular imju-ession. Fig. 9. A similarly preserved shell with but a single series of radial plications and showing tho peculiar reticulating surface sculptui'e. X 2. Niagara dolomites. Near Milwaukee, WiscoTisin. Orthis FLABELLITE8, Hall, var. Sjmnia, var. llo\^ See plates 5 and 20. Fig. 10. An internal cast of a pedicle-valve, having the expi-ession of 0. jlabeUites, but with scarcely more than one-half of the number of plications usual in this species. Niagara dolomites. Near Milicaukee, Wisconsin. Stropheodonta (Pholidostroi'hia) nacrea, Hall. See Plate 15. Fig. 11. The interior of a brachial valve ; showing the muscular scars and vascular sinuses. X 2. Hamilton shales. Livonia fialt iSliaft, Neic York. Stropheodonta (Brachyprion) profunda, Hall. See Plates 12 and 20. Pig. 12. A portion of an internal cast of a large pedicle-valve ; showing the cardinal ai-ea, the partial tilling of the delthyrium, the small adilui-tor and large diductor impressions. " ■ "' Niagara dolomites. Near Milwaukee, WiseoTUii7i. Stropheodonta (Douvillina) Cayuta, Hall. See Plate 1.5. Pig. 13. The interior of a pedicle-valve ; showing the elevation of the mu.scular .scar into a well defined platform j also the abrasion of the cardinal area by the teeth of the opposite valve. Chemung group. Steuben county. New York. Stropheodonta (Brachyprion) corruoata, Hail. See Plate Mi. Fig. 14. A jxjrtion of an internal cast of the pedicle-valve enlarged to show the crenulations of the hinge- plate, near the lieak. X 2. Clinton group. Rochester, New York. IB ia=^(B3iin®ip cDn>'^ Palaeont. N y.VolIVPT.ii-Vol.vni. MISCELLANEOUS Ooiu'iic Ilhistivilions Plate L XXXIV. G.B.Siit^son del Phil.Ast.lith. PLATK LXXXIV— Continued. Strophonklla costatula, s[). nov. Figs. 15, Ifi. Dorsal and profile views of the shell ; showing the revei-sed convexity of the valves and the shai-ply rounded, irregularly dichotomizing- plications. Niagara group. Loawville, Kentucky. Rafinesquina alteunata. Conrad. Figs. 17, 18. Enlargements of umbonal portions of internal casts of the pedicle-valve, to show the filling of the pedicle-passage. In fig. 18, which repi'esents the older shell, this filling is seen to be the smaller and is consti-icted at its hase, evincing thus the tendency of the shell to close this pas- sage at its inner extremity. X 3. Hudson River group. Erratic blocks hi western iVeio York. Productella navicella, Hall, See Plate 17. Fig. 19. A small pedicle-valve preserving the spines in a perfect condition and showing the convergence of the cardinal spines. X 5. Hamilton group. CanandaigvM Lake, Next) York. Strophalosia Rockfordensis, sp. nov. See Plate 17a. Figs. 20, 21, 22. Ventral, dorsal and cardinal views of a specimen ; showing the general extei-nal characters and the umbonal cicatrix Upper Devonian. Rockford, loxea.. Plectambonites producta, sp. nov. Figs. 23, 24, 25. Cardinal, profile and front views of an internal cast of a pedicle-valve ; showing the form of the teeth and muscular impressions, the short hinge and the greatly produced anterior margin. Niagara dolomites. Yellow Sprinffs, Ohio. Hyattei.la congesta, Hall. See Plate 40. Figs 26-28. Doi-sal, front and j)rofile views of one of the oi'iginal si)ecimens (Palaeontology of New York, vol. II. pi. xxiii, figs. 1, f, g, i). Clinton group, ilouroe coiiiity. New York. SriKiFEU L^vis, Hall. See Plate 38. Fig. 29. A portion of the cardinal region enlarged to show the peculiar structure of the deltarium, which beare a (nrcular jjerforation with elevateii margins, and is surrounded by an elongate, smooth area, at the edges of which the growth lines are sharply interrupted. X 3. Chemung group. Near Ithaca, New York. Seminula subquadrata, Hall. See Plate 47. Figs. 30, 31. Dorsal and profile views of the original specimen. Kaskasia limestone. Chester, Illiiwig. Cliothyris Royssii, L6veille. Fig. 32. The interior of a brachial valve ; showing the form of the hinge-plate. Coal Measures. Toumai, Belgium. Athyris conoentrica, voh Biicli. Fig. 33. An enlargement of the hinge-jilate ; showing its form, tripartite division, and apical perforation. Middle Devonian. Ferqiies, Brittany. I'LATK LXXXIV— Contlnaod. TOKYMFKH. gen. nov. TOKYMFKK CUITICUS, sp. IIOV. Ki(r»- '^■i- S5. A trHffint'iit of a ptdide-valvc, with well defined cardinal ai-ea. prominent tt^eth, convergent dental lamella' forming- a ilistinct spondjlium supported t)y a median septum. Nothing further is known of this peculiar shell. Its general relations are pi-obably less athyi-oid than orthoi.l. X 2 Though l)ut thifi fi-agn>«^nt 's known, it bears the critical sti-ucture which separates it from other geneni, and may hence a< well i-eceive a distinctive designation now as hereafter, when its other oharactei-s shall have been detei-mined. tit. Louis group. La Jtue, Kentucky. Spibifer (cf.) HiRTUs, Wliitc and Whitfield. See Plate 46. Kig. 36. A pedicle-valve, showing the compound spines at the concentric growth-lines, Fig. 37. A portion of the s&ine specimen enlarged, to show more distinctly the character of these spines. Waverly group. Jiichfield, Oh'w. NUCLEOSPIUA CONCINNA, Hall. See Plate 48. Fig. 38. Posterior cardinal view of the lirachial valve ; showing the elevation and curvature of the cardinal proceto. X 3. Hamilton group. Clarke county, Indiana NUCLEOSPIRA VKNTRICOSA, Hall. See Plate 48. Kig. 39. View of the cardinal process. X 13. Kig. 40. The same siiecimen projected backwai-d to show the elevation of the crui-al bases. Lower Helderberg group. Sc?ioharle, New York. Cyrtina neogenes, sp. nov. Fig. 41. Tlie jMjdicle-valve of a very transverse SpiRiKERiKA-like species, bi-oken so as to show the median septum supporting convergent dental plates. Chert of the Burlington limestone. BiirlingUm, Iowa. It is important to observe that this shell, with the extei-nal a.«pect of Spikifkrina and the interior structure of Cysti.va, !.< the pala>ozoic precurstir of numerous Triassic species passing under the name of Spirikerina, though assuredly not of that genus. Camarella Volborthi, Billings. See Plate . Fig. 42. A fragment of the umbonal portion of the shell, showing the Mi)ondylium of the pedicle-valve and the lateral walk of that of the brachial valve. X 3. 131>u;k River limestone. Paiiquette's Hapids, Canada. Anastrophia Verneuili, Hall. See Plate . Fig. 43. Caniinal view of a normal example, i-epresented with the j>e