= o -en ~cr> -CD ■o -CD cr> 'o / aT jMRw^ ' / L (©wlogial <^uritei) of tUe ,^tate of iicw i^orh. PALEONTOLOGY: VOLUME VIII._ AN INTRODUCTION TO THE STUDY OP THE GBNER A Pal^^ozoic Brachiopoda. Part II. JAMES HALL, STATE GEOLOGIST AJfl) PAL^ONTOI.DOIST. ASSISTED BT JOHN M. CLARKE. , "^- ALBANY, N. Y. : CHARLES VAN BENTHUYSEN & SONS, 1894. QH 105 M >-' 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 of 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 Palajozoic 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. Page. DEDICATION ............. [[[ TABLE OF CONTENTS ----..-.... v-vii PREFACE ix_xvi II. BRACniOPODA ARTICULATA (continued) ...... i 8pirifer -----........1 Ctrtia ..--.....-... 40 Cyrtina .---..--.-...43 Syringothtris .---..---.-- 47 Spiriperina -.-.-......--51 Amboccelia ------------ 54 Metaplasia -....-.-....- 56 Whitfieldella .-.-.---.--- 58 Hyattella ---------.-..61 Dayia .--.....---.. (52 HiNDELLA .--.....-.-..63 Meristina ............ 65 Merista ............. 70 Meristella ..--..----.. 73 Charionella .-...-----..78 Pentagonia .--.......-. 80 Camarospira .--.--.-.---82 Athyris ..---- 83 Cliothyris ----- 90 actinoconchus .-.....----- 92 Seminula ..-...----.-.93 Spirigbrella ------...--. 98 Kayseria - - - - - - - - - - -- -101 Retzia --..........- 103 Rhynchospira -- 108 Ptychospira ............ 112 • Uncites - - - - - - - - - - - - -113 Edmetria -..--- 115 acambona - - - - - - -119 HlISTEDIA -.-.--------- 120 Uncinella - 123 vi TABLE OF CONTENTS. BRACHIOPODA ARTICULATA (continued). Paije. Trematospira ------------ l-^** 197 Parazyga ..----------- i-i Anoplotheca ------------ l-^y CCELOSPIRA ------------- 1^4 Leptoc'celia ------------ lo6 VlTULINA ------ -- 138 Anabaia ------------- 141 nucleospira ------------- 142 Cyclospira ------------ 146 Glassia- ------- 152 Ztgospira ------------- 154 Catazyga ----- -- 157 Clintonella ------------ 159 Atrypina ------------- 161 Atrypa ------------- 163 Gruenewaldtia ------------ 175 Karpinskia -- - - - - - - - - - - 176 Rhynchonella ----------- 177, 178 Protorhyncha ------------ 180 Orthokhynchula ------------ 181 Rhynchotrema ------------ 182 Rhynchotreta ---------.-. 185 Stenoschisma ------------ 187 Camarotcechia ---------_.. 189 LlORHYNCHUS ------------ 193 WiLSONiA, Uncinulos, Uncindlina, Hypothyris ------ 195 PUQNAX ------------- 202 Eatonia ---. - 204 Cyclorhina ------------ 206 Terebkatuloidea -- -..- 208 Rhynciiopora --- -- 210 Camarophoria ---..-- 212 Stntrophia --- --- 216 Camarella ------------- 219 Parastrophia ------------ 221 Anastrophia ----..----.- 224 Porambonites ------------ 225 Lycophoria ------------- 230 conchidium ------------ 231 Pentamerus -- ..- 236 Barrandella, Pentamerella, Sieberella, Gypidula - - - . 241 Capellinia ------- 248 TABLE OF CONTENTS. vii BRACIIIOPODA ARTICULA.TA (contintted). Page. Stricklandinia ----------- 249 Amphigenia ------------- 252 Renssell^bia ------------ 255 Newberria ------------- 261 Centronella, Oriskania, Selenella, Ri imingerina, Trigeria, Notothyris - 265 ScAPHIOCCELIA ------------ 275 Megalanteris ------------ 277 Stringocephalds ------------ 282 Crtptonella ------------ 286 DiELASMA --------..---- 293 DiELASMINA -------- .--- 298 Hemiptychina ------------ 299 Crtptacanthia ------------ 300 Tropidoleptus ------------ 302 ElCHWALDIA ------------ 307 aulacorhynchus - - - - - - - - - - - -311 Lyttonia ------------- 313 Oldhamina ------------- 314 Richthofenia ------------ 315 Supplementary Note on Vitdxina --------- 317 Evolution op the Genera of the PALiEOzoic Brachiopoda - - - - 319 Table op Classification ----- 351 Descriptions of New Species --------- 359 INDEX -------- 371 PLATES AND EXPLANATIONS - - xxi-lxxxiv ERR^T^. Page 1, under Spirifbk, add Plates xxvii and xlvi. Page 43, under Cyktina, add Plate xxv ; change xxvii to xxviii. Page 47, under Striugothyris, add Plates xxv and xxxix. Page 51, under Spiriferixa, add Plate xxix. Page 54, under Amboocelia, add Plate xxix. Page 5S, under Whitfieldella, change Plate xlviii to xl. Page 61, under Hyattella, change Plate xlviii to xl. Page 63, under Hindella, adil Plate xlix. Page 65, under Meristina, change Plate xlvii to xli. Page 70, under Merista, change Plate xlvi to xlii. Page 73, under Meristella, change Plates xliv and xlv to xliii and xliv. Page" 8*?, under Camarospira, change Plate xlii to 1. Page S3, under Atuyris, add Plate Ixxxiii. Page 108, under Ruyncuospira, add Plate xlix. Page 112, under Ptychospira, add Plate Ixxxiii. Page 115, under Edmetria, add Plate Ixxxiii. Page 124, under Trem.vtospira, add Plate Ixxxiii. Page 134, under Ccelospira, add Plates lii and Ixxxii. Page 138, under Vitdlixa, change Supplementary Plate to Plate Ixxxii. Page 141, under Anabai.a, insei-t Plate Ixxxii. Page 142, under Nucleospira, add Plate Ixxxiv. Page 152, under Glassia, insert Plate Ixxxiii. Page 154, under Zygospira, change Plate Iv to liv, and add Plate Ixxxiii. Page 157, under Catazyga, change Plate Ivi to Iv. Page 161. undei- Atry'pixa, add Plate Ixxxii. Page 163, under Atrypa, change Plate liv to Iv. Page 182, under Rhynchotrema, add Plate Ixxxiii. Page 189, under CAMAROTOiCHTA, add Plate Ivi. Page 202, under Pugnax, add Plate Ixii. Page 230, under Lycopiioria, change Plate Ixiii to Ixii. Page 249, under Stricklandinia, add Plate Ixxxiii. Page 252, under Ampiiigesia, add Plate Ixxvi. Page 286, under Cryptonella, add Plates Ixxix and Ixxxi. Page 293, under Dielasma, add Plate Ixxx. PREFACE The present volume brings to a close the publication of the -PALEONTOLOGY OF NEW YORK: AS A PAKT OF TUE ''Natural i)i6tcivii of tl)c State of New flovk," according to the plan proposed and inaugurated by Governor William H. Seward during his administration, 1839-1842. At the time of the organization of the survey the question of publication had not been seriously considered ; the annual reports made to the Governor and communicated to the Legislature were necessarily published in the ordinary octavo document form. Hon. John A. Dix, in his report preceding the organization of the Geological Survey, had stated that " it is supposed that the entire account of the survey may be contained In three octavo volumes of 700 pages each," together with an atlas, which should contain the maps, " with the necessary drawings of fossil remains." This was the only suggestion regarding the final publication of the results of the survey. In November, 1839, the Board of Geologists made a special communication to the Governor, calling his attention to several matters of interest to the Geological Survey, and concluding as follows: " The board would also suggest to the Governor, as matters which will soon require attention, the mode and manner in which the final reports are to be published, and the number and style of maps, geological sections and diagrams."* At a later period it was decided that the entire work should be published in quarto form. * Assembly Document 50, January, 1840. X PREFACE. The order of the several departments, as set forth in the first published volume of the Natural History, was as follows : Central Jntroliuction : [By William H. Seward.] PART I. By James E. De Kay. PART 11. Botanij: By John Torrey. PART III. Blincialcigii : By Lewis C. Beck. PARTS IV and v.* (^cologn mib Ipalccontologn: By William W. Mather, Ebenezer Emmons, Lardner Vanuxem and James Hall. Agriculture was not prominent in the original plan of the survey, and repre- sentations coming from the State Agricultural Society, in 1842, led Governor Seward to recognize its importance in this relation. He decided that Agricul- ture and PalsBontology should be considered as departments to be continued and completed as a part of the Natural History of the State of New York. The Department of Agriculture was placed in charge of Dr. Ebenezer Emmons, who retained his position as State Geologist, and was also the custo- * After 1842 the Department of Geology was designated as Pai-t IV, Apiculture as Part V, and Palaeontotog-y as Part VI. PREFACE. xi dian of the entire collections of the Geological Survey, which constituted the State Cabinet of Natural History ; to the latter position he had been appointed by Governor Seward. Mr. Timothy A. Conrad, who occupied the position of Palaeontologist to the Geological Survey from 1837 to 1842, had published only such preliminary annual reports as were required of each department. At the latter date (1842) so little progress had been made in the work that only a small proportion of the characteristic fossils had been named or described. The Geologists there- fore found it necessary to give names to most of the fossils used in illustrating their reports, these species being the more common and characteristic forms of each group of the New York geological series. In the spring of 1843 the writer was placed in charge of the Palaeontology of the State, while still retaining his position as State Geologist.* At that time there were practically no collections of fossils available for use in the work, nor appropriations of money for making such collections. There were no artists, either for original drawings or for lithography, and there was very little in the way of books on Geology and Palaeontology. Mr. Conrad had estimated that a volume of one hundred quarto plates would be required to properly illustrate the fossils of all the formations in the State of New York. After the first year of exploration by myself and personal assistants, covering the entire series, from the Potsdam sandstones to the Che- mung group inclusive, it was found that no satisfactory a-ccount of the fossils of the whole series could be given in a single volume, and that it would be necessary to confine attention to those coming from the lower rocks.f From that time forward efforts were directed to the preparation of descriptions and illustrations of fossils characterizing the lower division of the " New York system," which appeared in the first volume, published in 1847, containing 362 pages and ninety-nine plates of illustration. In that volume due recognition was made of the sources from which material had been obtained for illustrating the work. Since that time * See Preface to vohune I, Palaeontology of New York. t At the end of the first year (in 1844) the question of continuing' the Departments of Agi-iculture and Pal.-Eontology wa-s bi-ought before the Legislature, and ;in extension of time allowed for the completion of the work, but no appropriation beyond the salaries of the officials was granted. xii PREFACE. acknowledgments have been duly expressed, not only to amateur collectors of fossils, but also to professors in colleges and scientific gentlemen generally, both within the State and beyond its borders, for their willing aid in the progress of the work. Without such aid some portions could not have been properly illus- trated (as I was compelled to depend solely on my own purse for collections made in the field during the preparation of the earlier volumes). These volumes (I, II, III), therefore, present a less complete illustration of the faunas of the geological formations to which they refer, than do the later volumes, which were published after the State had furnished means for making field collections. Volumes I and II should be revised and republished with all the added knowledge of these faunas obtained during the past third of a century. This work, from its commencement in 1843, has been prosecuted amid many difficulties, and often under conditions which would have justified its final abandonment. These hindrances have been overcome, and a series of volumes has been published, and accepted as a contribution to the scientific literature of the world. The work in the agricultural and palaeontological departments was carried on in the old State Hall (State Cabinet of Natural History) on State street, until 1845, when the authors were compelled to remove themselves and their work from the building. This requirement proved seriously burdensome to the Palaeontologist, necessitating at once the erection of a building of moderate size with ordinary working rooms ; and afterwards (when the Legislature began to make appropriations for collections of fossils), two extensive buildings were found necessary ; these were erected at my own cost and fitted up with about four thousand drawers, for the proper disposition of the immense collections brought in from the field, together with rooms and conveniences for the prepara- tion, study and arrangement of fossils, and offices for draughtsman and lithographer ; and they were occupied as a museum and laboratory till the end of 1886. Prior to 1871 the Legislature made no provision for the expenses of these or any other working rooms, nor for clerk hire and incidental outlay. From 1850 onward for several years no appropriations were made for carry- ing on the work, and even the author's small salary was discontinued. From PREFACE. xiii 1850 to 1855 the work, except the printing and lithography, was carried on entirely at the author's personal expense, and it was abandoned early in the latter year* Afterwards, in the same year, Hon. E. W. Leavenworth, Secretary of State, undertook to reestablish the work upon a proper basis, and the author was induced, by an appeal to his patriotism, to take it again in charge. To do this, he declined a position which would have insured him security of place and a life of quiet investigation in geological science. Under the new arrangement, for the first time in the history of the work, means were provided for the collection of fossils to illustrate the volumes still to be published. Because of these collections the work was necessarily much extended, and Volume V, originally planned as a single volume, including text and plates, has been expanded to four volumes. Volumes VI and VII, and all subsequent work, * The following exti-ant tVom Ihe Pref;ic:e ol' Voluiiie III will give :i more clt-ar idea of the then existing conditions : " This department of the Geological Survey of the State was committed to my charge in 1843 ; Volume I was completed and inililished in 1847 j and Volume II, so far as regarded my own Labors, was completed in ]8.")0, and the work of the third volume wan at that time in progress. In the spiing of that year, legis- lative enactment removed the direction of this woi'k from the Govei-nor of Ihe State, and jilaced it in the hands of Ite Secretary of State, who was ' authorized and directed to t.ike charge of all matters appertain- ing to the prosecution and publication of the Geological Survey of the State ; ' and in Ihe third section of the the same law, it was made 'the duty of the Secretary of State and the Se<^retary of the Regents of the University, to report to the next Legislature a plan for the final completion of the said survey, and to submit the estimate of the cost of such completion/ " lu the Reiioi't fi-om this Commission to the Legislature a pi-oposition was made to pay the Paljeontol- ogist ' two thousand five hundred dollars ' on the ' presentation of each successive volume, commencing with the third, to the Secretary of State ;' which volume was to 'contain the manuscript letter-press ready for printing, and be .accompanied with the very fossils described.' " This 'proposition' was 'deemed ajii.st and liberal one,' and it seems to have been anticipated that the work would go on under such conditions. The sum of money here proposed to be paid to ilcfi'ay the entire expense of collecting the fossils and Ihe study and description of the same, together with the labor of super- intending Ihe drawings and engraving, was in fact entirely inadequate to pay for the collection of the fo.ssils neces.sai'y for a single volume, and left, besides this, more than four yeai's of labor to l)e performed by the Palteontologist without any remuneration whatever. Under these circumstances the work could not go on, and it became by this act virtually susj)ended in the early piii't of 1850. " From the commencement of the wcu'k, the expenses of making the collections had been borne by myself. These collections, made up to that time, not only embraced most of those of the fii'st ami second volumes, but the greater part of the third volume, as well as extensive collections in the higher rocks of the New York series for the succeeding volumes. Besides these, I had made large collections of fossils in the same series of strata in the west, for the purpose of comi>arison with the New York species. In this way, as well as in examinations of the rock formations in situ, over a lai-ge part of the Western States, for the purpose of determining the parallelism of the formations, I had already made great [lecuniary saci-ifices in carrying on the work. Under these circumstances, therefoi'e, and with the new aspect presented by the law of IS.W, and the action of the Commission relative thei-eto, I could no longer devote myself to its prose- cution, and consequently made other arrangements for the occupation of my time, which, however, left me still some opportunity to continue ray investigations in this work. As the contracts between the State and the engravers continued in force, the engi'aving, after 1851, was carried on somewhat slowly ; my frequent a,nd protiacted absence rendering it impossible for me to give that personal attention to it which a work of this kind so fully demands. In order to jirevent its entire cessation, I employed a person as an assistant (who afterwards became my draughtsman) ; the lithographer volunteering to contribute to i).ay a portion of the expense of such assistant, that his own work might not cease entirely. In this way the work was con- tinued till 1855, no compensation whjitever being paid to the author during this jieriod." xiv PREFACE. have profited by the collections of fossils made from 1856 to 1865 inclusive, when appropriations for such collections ceased. This final volume (VIII, Part II), after being held back for one year through want of an appropriation, was printed to page 317 in the autumn of 1893. At that point the printing was again suspended. In order to have a record of the date of the completed work, there was issued, in July, 1893, a fascicle containing the text, from page 1-176; embracing descriptions of the spire- bearing genera; and a second fascicle in December, 1893, carrying the text to page 317, including descriptions of the rhynchonelloids, pentameroids and terebratuloids. At that time the concluding chapter or summary was in type, but the appropriation having been exhausted the printer was compelled to sus- pend all work upon the volume ; so that this chapter, bringing the text up to 350 pages, together with accompanying and concluding matter, was laid over to the present year. In the original scheme of the work on the Brachiopoda the generic descrip- tions were to be accompanied with illustrations of the microscopic structure of the shell, but it was found inconvenient to accomplish this plan during its progress ; though a large number of sections were prepared for microscopic study. This part of the work is postponed for the present, and probably will not be taken up again by the writer. The great length of time since these studies were resumed in 1888, has enabled those assistants who were with me in the earlier preparation of the work to advance their investigations in the same line of concept, and to anti- cipate some of the results which have been reached in these volumes. While the final result in this direction is still distant, it is encouraging to see the work advancing in what the writer believes to be the only true method of studying every class of organisms. In the Preface to Part I of Volume VIII, the author made acknowledgments to many personal friends, to collectors of fossils, to museums and geological surveys ; he wishes to repeat these acknowledgments in the Preface to Part II, since this will probably be his last opportunity of connecting their names with the progress of the " Palaeontology of New York." PREFACE. XV During the fifty-one years which have elapsed since the commencement of this work, I have had many assistants who directly or indirectly have aided in, or have contributed to its progress. Among the earliest of these was Mr. Fielding B. Meek (afterwards Palaeontologist to the United States Geological Survey of the Territories), whose services were largely given to the drawings for the plates of Volume III, which were lithographed by Mr. Frederick J. SwiNTON, the latter continuing his connection with the work till 1872, enriching the volumes by his excellent artistic work. During the early part of the same period, Mr. Ferdinand V. Havden, who subsequently became Director of the U. S. Geological Survey, was my assistant, and, together with Mr. Meek, made a survey of the Mauvaises Terres of Nebrasl^a, at my personal expense. Dr. Charles A. White, now of the National Museum at Washington, who had been my assistant in the Iowa Survey, was, for one year, engaged in the service of the Palaeontology of New York, in making field collections and obtaining geological data. Mr. Robert P. Whitfield, now Curator of Geology in the American Museum of Natural History, was associated with me as preparateur, draughtsman and genei*al assistant in the work for twenty years (1856 to 1876). After this date Mr. Charles 1). AValcott, now Director of the U. S. Geological Survey, became my assistant for two years. In the final revision and publication of the four volumes, which constitute Volume V, I had the assistance of Mr. Charles E. Beecher, now Professor in Yale University, from the commence- ment of the Cephalopoda to the completion of the Lamellibranchiata, from 1878 to 1885. Mr. George B. Simpson, who has served the work for many years as draughtsman, has made himself very familiar with the Bryozoa and Corals of our geological formations, and has given very essential aid in the preparation and publication of Volume VI, as well as in other work connected with the Palaeontology. He has also contributed to tlie State Museum re- ports a study on the Anatomy and Physiology of the Anodonta Jluviaiilis. In the capacity of my private assistant, the services of Mr. Charles Schuchert, now of the U. S. National Museum, were given to the forwarding of Volume VIII, as already stated in the Preface to Part I. Professor J. M. Clarke, who came into the work in 1886, has given essential aid in the preparation of xvi PREFACE. Volumes VII and VIII, as already related in the former volume, and also in Part I of the present volume, and has remained with me to its conclusion. From the beginning of the work it has been the ambition of the author to secure accurate and artistic illustrations of the subjects under discussion. In the earlier part of the work these conditions could not be obtained, but in later years the style and accuracy of the representations has left little to be desired. In the Preface to Part I of this volume, I made acknowledgments to the draughtsmen and lithographers who have been engaged upon this work. The original drawings have been continued by Mr. Ebenezer Emmons and Mr. George B. Simpson, and the lithography by Mr. Philip Ast, who have attained a degree of perfection in their work of which it is my duty as well as my pleasure to speak in praise. My thanks are due to the printers, Messrs. Charles Van Benthdysen & Sons, now the veteran printing house of the country, with an uninterrupted intercourse to the fourth generation ; covering a period of more than fifty years. To the many successive Legislatures of the State of New York, as well as to the Chief Executives, the scientific public is indebted for the volumes which have been published under the title of Paleontology of New York. In every Legislature the author has found gentlemen who were interested in science, and who were in sympathy with this work. Not only among members of the Legislature but among those who had previously held legislative and executive offices, as well as other prominent citizens of the State, the work has found encouragement and support. The people of the State may have the satisfac- tion of knowing that no other State legislature has sustained, through so many years, a scientific investigation carried on for the sake of science itself, and without anticipating direct economic results. For all this good-will and liber- ality to science, the writer desires to express, for himself and his scientific co-laborers, the most profound acknowledgments. JAMES HALL, State Geologist and Pal&ontologist. Albany, N. Y., December 5, 1894. INTRODUCTION STUDY OF THE GENERA OF THE PALAEOZOIC BRACHIOPODA. II. BRACHIOPODA ARTICULATA (CONTINUED). Genus SPIRIFER, Sowerby. J815. PLATES XXI— XXV, XXIX— XXXIX. 1815. iSpirifer, Sowebby. Mineral Conchology, vol. ii, p. 42. 1818. Spirifer, Sowerbt. Trans. Linnean Society, vol. xii, p. 514. 1820. Terehratula, Atwater. American Journal of Science, vol. ii, p. 244, pi. i, fig-s. 2, 3. 1836. Spirifer, Morton. American Journal of Science, vol. xxix, pp. 1.^0, l.')2, pi. ii, figs. 1. 3 ; pi. xiv, figs. 34, 35. 1839. Delthyris, Conrad. Geol. Survey N. Y. ; Thii-d Ann. Rept. Pateont. Dept., p. 65. 1840. Delthyris, Conrad. Geol. Survey N. Y. ; Fourth Ann. Rept. Pala;ont. Dept., p. 207. 1841. Delthyris, Conrad. Geol. Survey N. Y. ; Fifth Ann. Rept. Palfeont. Dept., p. 54. 1842. Delthyris, Conrad. Jour. Acad. Nat. Sci. Philadelphia, vol. viii, pp. 261-265, pi. xiv, figs. 16-18. 1842. Spirifer, D'AntmiAC and de VBBNEniL. Fossils of the older deposits of the Rhenish Provinces, p. 394. 1842. Delthyris, Orthis, Vanuxem. Geology of N. Y. ; Rexiort Third Dist., pp. 91, 94, 105, figs. 1, 2 ; p. 112, fig. 1 ; p. 123, fig. 1 ; p. 124, fig. 5 ; p. 132, fig. 3 ; p. 150, fig. 3 ; p. 179, fig. 3 ; p. 269, fig. 1. 1842. (Spiiv/er, d'Orbigny. Voyage dans I'Amei'ique Meridionale, Pal., pp. 41, 48, pi. v, fig. 15; pi. xii, figs. 1, 2. 1843. Delthyris, Mather. Geology of N. Y. ; Rept. First Dist., p. 342, fig. 1. 1843. Delthyris, Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 105, figs. 3, 4 ; p. 142, fig. 1 ; p. 148, tig. 1 ; p. 171, fig. 5 ; p. 198, figs. 2, 3 ; p. 200, fig. 5 ; pp. 202, 205, fig. 3 ; pp. 206. 207, figs. 1, 2, 5; p. 208, figs. 8, 10; p. 245, fig. 1; p. 269, figs. 3. 9 ; p. 270, figs. 1-5. 1843. Spirifer, Castelnad. Essai sur le Systfeme Silurien de I'Am^rique Septentrionale, pp. 40^3, pi. xii, figs. 3-6 ; pi. xiii, figs. 1, 4, 5 ; pi. xiv, figs. (1) 7, 16. 1844. Delthyris, Owen. Rept. Geol. Expl. of Iowa, Wisconsin and Illinois, p. 69, pi. xii, fig. 9. 1846. Spirifer, Morris and Sharps. Quart. Jour. Geol. Soc. London, vol. ii, p. 276, pi. ii, figs. 1-3. 1847. Spirifer, Yandell and Shumard. Contribution to the Geol. of Kentucky, pp. 10, 14, 20, 33. 1849. Spirifer, Hall. American Journal of Science, vol. xx, p. 228. PALEONTOLOGY OF NEW YORK. 1852. iSpirifer, Hall. Paleontology of N. Y., vol. ii, pp. 66, 261-265, 327, 328, pi. xxii, figs. 2d, 2r, 3 ; pi. liv, figs. 2-6 ; pi. Ixxiv, figs. 7-9. 1852. Spirifer, F. Roemek. Kreidebildung von Texas, p. 88, pi. xi, fig. 7. 1S53. Spirifer, Hall. Stansbury'a Expl. and Survey of the Valley of the Gi-eat Salt Lake of Utah, p. 410, pi. iv, fig. 5. 1852. Spirifer, Owen. Geol. Survey Wisconsin, Iowa and Minnesota, pp. 585, 586, pi. iii, figs. 1-6, S; pi. V, figs. 4, 6. 1854. Spirifer, Nokwood and Pratten. Jour. Acad. Nat. Sci. Philadelphia, vol. iii, jip. 72, 73, pi. ix, figs. 2, 3. 1855. Spirifer, Shdmard. Geol. Survey of Missouri, pp. 202, 203, 216, pi. c, figs. 7, 8. 1856. Spirifer, Hall. Pacific Railroad Reports, vol. iii, pp. 101, 102, pi. ii, figs. 6-9, 12. 1856. Spirifer, Billings. Canadian Naturalist and Geologist, vol. ii, p)). 134, 135, 137, 474, pi. ii, figs. 2, 3, 7, 8, pi. vii, figs. 9, 10. 1857. Spirifer, Haughton. Journal of the Royal Society of Dublin, vol. i, p. 183. 1857. Spirifer, Orthis, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., pp. 57, 58, 60-03, 127-135, 154-164. 1857. Spirifer, Hall. Transactions of the Albany Institute, vol. iv, p. 8. 1858. Spirifer. Hall. Geology of Iowa. vol. 1, part ii, pp. 501-511, 519-521, 600-604, 641-645, 647, 660-663, 676, 705, 706-708, 709-711 ; pi. iv, figs. 1-8 ; pi. v, fig. i; pi. vi, fig. 1 ; pi. vii, figs. 5, 7, 8 ; pi. xiii, figs. 1-3 ; pi. xiv, figs. 1-5 ; pi. xx, figs. 1-5, 7 ; pi. xxi, fig. 1 ; pi. xxiii, figs. 6-9; pi. xxiv, fig. 4 ; pi. xxvii, figs. 4, 6 ; pi. xxviii, figs. 1, 2, 1858. Spirifer, Mahcou. Geology of North Amei ica, pp. '49, 50, pi. vii, figs. 2, 4, 5. 1858. Spirifer, DtWiyris, Rogeks. Geology of Pennsylvania, vol. ii, part ii, p. 825, fig. 643 ; p. 826. fig. 650 J p. 828, figs. 668-670, 673 ; p. 829, fig. 683 ; p. 833, fig. 694. 1858. Spirifer, Shumard. Trans. St. Louis Acad. Sci., vol. i, pp. 292, 293, 390 ; pi. xi, figs. 3, 4. 1859. Spirifer, Hall. Palffiontology of N. Y., vol. iii, pp. 198-205, 419-428, plates xxv, xxvi, xxvii, xxviii, xcvi, figs. 7-9 ; pi. xcvii, xcviii, figs. 1-8 ; pis. xcix, c. 1859. Spirifer, Mbek and Hatdbn. Proc. Acad. Nat. Sci. Philadelphia, vol. iii, second ser., p. 27. 1859. Spirifer, Shumard. Trans. St. Louis Acad. Sci., vol. i, p. 391. 1860. Spirifer, Hall. Canadian Naturalist and Geologist, vol. v, p. 145. 1800. Spirifer, Meek. Proc. Acad. Nat. Sci. Philadelphia, vol. iv, second ser., pp. 308-310. 1860. Spirifer, Hall. Thii'teenth Rept. N. Y. State Cab. Nat. Hist., pp. 71, 82, 94, 111. 1860. Spirifer, Ambocalia, McChb.snby. New Paljeozoic Fossils, pp. 41-43. 1860. Spirifer, Swallow. Ti'ans. St. Louis Acad. Sci., vol. i, pp. 641-646. 1860. Spirifer, F. Roemer. Die silurische Fauna des westlichen Tennessee, p. 68, pi. v, fig. 8. 1860. Spirifer, Emmons. Manual of Geology, p. 151. 1860. Athyris, Billings. Canadian Joui'., vol. v, new ser., p. 276, figs. 33, 34. 1861. Spirifer, Newberry. Ives' Rept. Colorado river of the West, p. 127. 1861. Spirifer, McChesnet. New Palteozoic Fossils, p. 84. 1861. Spirifer, Hall. Ann. Rept. Geol. Survey of Wisconsin, pp. 25, 26. 1861. Spirifer, Billings. Canadian Jour., vol. vi, new ser., pp. 253, 254, figs. 59-62; p. 255, figs. 63, 64 ; p. 256, figs. 6.5-67 ; p. 257, figs. 68-70 ; p. 258, figs. 71-73 ; p. 260, figs. 74-76 ; p. 261, figs. 77, 78. 1861. Spirifer, Meek and Wortuen. Proc. Acid. Nat. Sci. Philadelphia, vol. v, second ser., p. 143. 1862. Spirifer, White. Proc. Boston Soc. Nat. Hist., vol. ix, p. 24. 1862. Spirifer, White and Whitfield. Proc. Boston Soc. Nat. Hist., vol. viii, p. 293. 1862. Spirifer, Winchell. 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. DeltUyris (Conrad) Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., pi. xi, fig. 18. 1863. Spirifera, Davidson. Quart. Jour. Geol. Soc. London, vol. xix, pp. 170, 171, pi. ix, figs. 7-10. 1863. Spirifer, Athyris, Billings. Geology of Canada, p. 317, figs. 328, 329 ; p. 372, figs. 391-394 ; p. 373, fig. 398 ; p. 386, figs. 422-424 ; p. 957, figs. 455-457 ; p. 960, figs. 465-467. BRACHIOPODA. 3 1863. iSpirifei; Swallow. Trans. St. Louis Acad. Sci., vol. ii, pp. 85, 86, 108. 180a. iSplrifer, Hall. Transactions of the Albany Institute, vol. iv, pp. 211, 212. 1863. ^pirifei; Billings. Pi-oc. Portland Soc. Nat. Hist., vol. i, pp. 116, 117, pi. iii, tig-s. 15-17. 1864. tSinrifera (Maiihiia), Meek and Hayuen. Pal. Upper Missouri, pp. 17, li>. 20. 1864. Spirifera, Meek. Palseontolog-y of California, vol. i, p. 13, pi. ii, fig-. 6. 1865. Spirifera, Winchell. Proc. Acad. Nat. Sci. Philadeliihia, vol. ix, second ser., pp. 118, 119. 1865. Spirifera, Sualer. Bull. Mus. Comparative Zoology, No. iv, p. 70. 1866. Spirifera, Geinitz. Carbon und Dyas in Nebraska, pp. 42, 44, 45, pi. iii, figs. 10, 18. 1866. Spirifera. Murtinia, Winchell. Geological Report of the Lowei- Peninsula of Michigan, pp. 93, 94. IStJO. Spirifera, Swallow. Trans. St. Louis Acad. Sci., vol. ii, pp. 408-410. 1866. Spirifera, Billings. Catalogue Silui-ian Fossils of Anticosti, p. 48. 1866. Spirifera, Meek and Wokthen. Geol. Survey of Illinois, pp. 155, 298, pi. xiv, fig. 5 ; pi. xxiii, tig. 5. 1866. Spirifera, Hall. Proc. American Philosophical Society, vol. x, p. 246. 1867. Spirifera. Hall. Palteontology 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. State Cab. N;it. History, [ip. 251, 370, 371, i)l. xiii, figs. 5-11, 14, 15. 1868. Spii-ifera (Martinia), Meek. Ti-ans. Chicago Acail. Sci., vol. i, pp. 101-107, pi. xiv, figs. 1-3, 9, 12. 1868. Spirifa-a {Martinia), McChesney. Trans. Chicago Acad. Sci., vol. i, pp. 34-36, pi. i, figs. 3, 4 ; pi. vi, fig-. 5 i pi. viii, fig. 3. 1868. Spirifera, Meek and Wokthen. Geol. Sui-vey of Illinois, vol. iii, pp. 298, 384, 391), 414, 415, 434, 443, pi. vii, tig. 9 ; pi. viii, figs. 5-7 ; pi. x, figs. 1, 2, 5 ; pi. xiii, fig. 8. 1869. Spirifera, Toula. Sitznngsl). d. k. k. Akad. Wissen. zu Wien, vol. lix, p. 3, pi. i, tigs. 2-4. 1870. Spirifei-a, Winchell. Proc. American Philosophical Soc, vol. xii, pp. 245, 251, 252. 1870. Spirifera, Meek and Worthen. Proc. Acad. Nat. Sci. Philadelphia, vol. xiv, sec. ser., p. 36. 1870. Spirifera (Trigonotreta), Meek. Proc. Acad. Nat. Sci. Philadelphia, vol. xiv, sec. ser., p. 60. 1871. Spirifera {Trigonotreta). Meek. Proc. Acad. Nat. Sci. Philadelphia, vol. xv, sec. ser., p. 179. 1872. Spirifera {Martinia), Meek. Hayden's Rept. U. S. Geological Suivey of Nebraska, pp. 183, 184, pi. ii, fig. 3 ; pi. iv, fig. 4 ; pi. vi, fig. 12 ; pi. viii, tigs. 2, 15. 1872. Spirifera, Hall and Whitfield. Twenty-fourth Rept. N. Y. State Cab. Nat. Hist., p. 182. 1873. Spirifera, Hall and Whitfield. Twenty-third Rept. N. Y. State Cab. Nat. Hist., pp. 237, 238, pi. xi, tigs. 12-24. 1873. Spirifera, Meek. Sixth Ann. Rept. U. S. Geol. Survey of the Terr., pp. 466, 470. 1873. Spirifera, Meek and Wortuen. Geological Survey of Illinois, vol. v, pp. 572, 573, pi. xxv, figs. 5, 7. 1874. Spirifera, Rathbun. Bull. Buffalo Soc. Nat. Sci., vol. i, pp. 237, 239, 241, pi. viii, figs. 1-9, 11, 13-21 ; pi. ix., fig. 22. 1874. Spirifera {Martinia), Derby. Bull. Cornell University, vol. i, pp. 13, 15, 16, 19, plates i-v, viii, ix. 1874. Atliyrisf, Spiriferina, Nicholson. Paheontology of Province of Ontario, pp. 82, 88. 1874. Spirifera, Billings. Palajozoic Fossils, vol. il, pp. 44, 45. 47, jil. iii, fig. 8 ; pi. iii a, figs. 3, 5. 1875. Spirifera, Meek. PaK-eontology 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, tigs. 7, 8, 10; pi. x, figs. 1-3; pi. xi, fig. 9. 1875. Spirifera, Meek and Worthen. Geol. Survey of Illinois, vol. vi, pp. 521, 523, pi. xxx, tigs. 1-3. 1875. Spirifera, Hall and Whitfield. Twenty-seventh Rept. N. Y. State Cab. Nat. Hisloi-y, pi. ix, tigs. 11-13, 17, 18. PALEONTOLOGY OF NEW YORK. 1876. iSpirifera, Meek. Simpson's Rept. Expl. Great Basin of the Terr, of Utah, pp. 345-347, 351, 353, pi. i, fig-s. 1, 4, 5 ; pi. ii, figs. 3, 5. 1876. Spirifera, Derby. Bull. Mus. Comparative Zoologry, vol. iii, p. 279. 1876. Spirifera, Meek. Bull. U. S. Geol. Survey of the Terr., vol. ii, p. 355, pi. i, fig. 3. 1877. Spirifera, Hall and Whitfield. King's U. S. Geol. Expl. Fortieth Parallel, vol. iv, pp. 254, 255, 269, 270, pi. iv, figs. 5-8 ; pi. v, figs. 13-15, 17, 18. 1877. Spirifera {TrigortotrHa), Meek. King's U. S. Geol. Expl. Fortieth Parallel, vol. iv, pp. 39-4.'), 88, 90, 91, pi. i, fig. 9 ; pi. iii, figs. 1, 3, 5 ; pi. iv, fig. 4 ; pi. ix, figs. 1, 2, 6. 1878. Spirifera, -Dkyi&OTi. Acadian Geology, third ed., p. 292, fig. 91 ; p. 291, tig. 89; pp. 301, 499, fig. 176 i pp. 596, 597. 1878. Spirifera, Ethekidge. Quart. Journal Geol. Society London, vol. xxxiv, pp. 628, 629, 633, 634, pi. XXV, fig. 5 ; pi. xxix, figs. 1, 2. 1878. Spirifera, Miller. Proc. Davenjiort Acad. Sci., p. 222. 1879. Spirifera. Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. History, pp. 156, 157, pi. xxiv, figs. 1-30. 1879. Spirifera, Rathbcn. Proc. Boston Soc. Nat. Hist., vol. xx, pp. 25-30. 1879. Spirifira, Dawson. Canadian Naturalist and Geologist, vol. ix, second ser., p. 3. 1880. Spirifera, yfaiTB. Second Ann. Rept. Indiana Bui-eau of Statistics and Geol., pp. 497, 503, 504, 517, plate iii, tigs. 5, 6 ; pi. iv, tigs. 1-5, 10, 11 ; pi. viii. fig. 3. 1880. Spirifera, Williams. American Journal of Science, vol. xx, p. 456. 1881. Spirifera (Martinia), Williams. Annals N. Y. Acad. Sci., vol. ii. 1881. Spirifera, Miller. Jour. Cincinnati Soc. Nat. Hist., vol. iv, pp. 2, 314, pi. vii, figs. 9, 10. 1881. Spirifera, White. Tenth Rept. State Geol. of Indiana, pp. 129, 135, 136, 149, pi. iii, figs. 5, 6 ; pi. iv, figs. 1-5 ; pi. viii, tig. 3. 1881. Spirifera (Martinia), White. Wheeler's Expl. Survey west of the 100 Meridian, vol. iii. Appen- dix, p. xii. 1882. Spirifera, Whitfield. Bull. American Mus. Nat. Hist., vol. i, p. 47, pi. vi, figs. 13-15. 1882. Spirifera, ? Spiriferina, Whitfield. Geol. Wisconsin, vol. iv, pp. 287, 328-331, pi. xvii, figs. 1, 2 ; pi. XXV, figs. 22-28 ; pi. xxvi, tigs. 1-4. 1882. Spirifera, Hall. Eleventh Rept. State Geologist Indiana, pp. 294-297, pi, xxiv, tigs. 1-20, 30 ; pi. xxvii, figs. 8, 9. 1882. Spirifera (JShutinia), White. Eleventh Rept. Slate Geol. Indiana, p. 372, pi. xlii, figs. 4-6. 1883. Spirifera, Hall. Twelfth Rept. State Geol. Indiana, p. 326, pi. xxix, figs. 13-15. 1883. Spirifera, White. Twelfth Rept. U. S. Geological Survey Terr., pp. 135, 165, pi. xxxiv, tig. 10 ; pi. xli, fig. 2. 1883. Spirifera, Hall. Second Ann. Rept. N. Y. State Geol., plates li-lx, figs. 1-18 ; pi. Ixi. 1883. Spirifera, Hall. Transactions of the Albany Institute, vol. x, p. 71. 1883. Spirifera, Calvin. American Journal of Science, vol. xxv, p. 433. 1884. Spirifera (Martinia), White. Thirteenth Repc. State Geologist of Indiana, pp. 132-134, pi. xvii, figs. 4-6 ; pi. xxxii, tigs. 23, 24 j pi. xxxv, figs. 3-5. 1884. Spirifera {Martinia), Walcott. Monogr. U. S. Geol. Survey, vol. viii, pp. 134-139, 143-145, 215- 217, pi. iii, figs. 1, 3, 5, 6 ; pi. iv, tigs. 1, 2 ; pi. vii, fig. 8 ; pi. xiv, figs. 3, 10-12, 14 ; pi. xviii, figs. 4, 7, 10, 11. 1885. Spirifera, Clarke. Bull. U. S. Geol. Survey, No. 16, pp. 30, 31, pi. iii, tigs. 12, 13. 1886. Spirifera, Ringueberg. Bull. Buffalo Soc. Nat. Sci., vol. v, p. 16, pi. ii, fig. 5. 1887. Spirife)'a {Martinia), Hbkrick. Bull. Denison University, vol. ii, pp. 45, 46, pi. i, figs, 12, 13 ; pi. ii, tigs. 22, 23. 1888. Spirifera, Hkrrick. Bull. Denison University, vol. iii, pp. 43-46, pi. ii, fig. 16 ; pi. iii, fig. 26 ; pi. V, figs. 2, 3 ; pi. vi, figs. 2-4, 6, 7 ; pi. vii, fig. 11 ; vol. iv, pp. 14, 25-27, pi. ii, figs. 2, 4, 7, 8. 1888. Spirifera, Keyes. Pioc. Acad. Nat. Sci. Philadelphia, p. 9. 1888. Spirifera, Calvin. The Ameiican Geologist, vol. i, p. 82. BRACHIOPODA. 5 1888. Spirifera, Calvin. Bull. Laboratory Stale University of Iowa, pp. 19, 28, 1889. Spirifera, Nbttelroth. Kentucky Fossil Shells, pp. 105-184, pi. vi, vii, viii, ix, x, xi, xii, xiii, tigs. 3ti-38 ; pi. xvii, figs. 36-42; pi. xxvi, figs. 2-5; pi. xxi.\, tigs. 13-16, 2'i ; pi. xxxi, figs. 10, 11, 13; pi. xxxii, fi.'rs. 28-31 ; pi. xxxiii, fig.-^. 2:'„ 24. 1889. Spirifer, Beechbr and Clarke. Memoirs N. Y State Museum, pp. 75, 77, pi. vi, tigs. 1-7, 9-11. 1889. Spirifera, Whiteaves. Contributions to Canadian PalEeontology, vol. i, p, 114, pi. xv, fig. 3. 1890. Spirifera, Wohthen. Geol. Survey of Illinois, vol. viii, p. 105, pi. xi, fig. 5. 1890. Spirifera, Foekstb. Proc. Boston Soc. Nat. Hist., vol. xxiv, p. 313, pi. v, figs. 5, 6. 1890. Spirifera, Williams. Bull. Geol. Soc. America, vol. i, p. 491, pi. xii, figs. 12, 13. 1890. Spirifera, Hall. Bull. Geol. Soc. America, vol. 1, p. 567. 1890. Spirifera, Hall. Ninth Ann. Rept. N. Y. State Geologist, p. 9. 1891. Spirifei-a, Hebrick. Bull. Geol. Soc. America, vol. ii, p. 45, pi. 1, fig. 18. Shells transversely elongate, rarely produced axially ; with or without me- dian fold and sinus. Hinge-line straight, usually forming the greatest diameter of the shell, but in some of the subdivisions of the genus, short and inconspicu- ous. Cardinal extremities alate, acuminate or rounded. Surface covered with granulations, striae, plications or costse, variously grouped and which may be present or absent on the median fold and sinus ; these are crossed by concentric growth-lines which may take the form of varices or expanded lamellag, or be modified into fimbriaj of simple or compound spines. In the subgenera Martinia and Martiniopsis the surface is smooth except for the concentric striae. Shell substance fibrous, impunctate except as below described ; in the smooth species the epidermal layer is minutely pitted. The pedicle-valve has the umbo more or less elevated over the hinge-line, the apex acute, erect or incurved. The cardinal slopes show a slight tendency to concavity or excavation, and the median portion of the valve is more or less strongly depressed by a sinus. The cardinal area is broad, flat or incurved and its surface is transversely striated ; the inner shell-layers bear a series of longi- tudinal or vertical canals at whose marginal extremities the fibrous tissue is produced into a row of denticles, corresponding to a row of pits on the opposite valve ; thus forming an accessory articulation of the valves. The essential articulation is effected by means of stout, simple teeth lying at the marginal extremities of the triangular deltidium and supported by dental plates which are usually short, but, in rare types, may be produced even to the anterior mar- gin of the valve The pedicle-passage or delthyrium is usually open. Nor- mally it is closed by a pair of deltidial plates having the form of scalene tri- 6 PALEONTOLOGY OF NEW YORK. angles, which develop from the sides of the delthyrium and meeting, enclose wholly or partially a circular or oval pedicle foramen. At normal maturity these plates become anchylosed along the median suture and form a single con- vex plate (the so-called pseudodeltidium). The usual absence of the deltidium may be due either to accidental removal or to resorption with advancing growth. In the adult and senile stages of de- velopment many species, especially in the line of development to Syringothyris, form a testaceous callosity in the pedicle-cavity, thickening the umbo and ex- tending across the delthyrium, reaching in extreme cases, nearly to the cardinal margin. The muscular area consists of a subtriangular pedicle-impression occupying the pedicle-cavity, and continuous with a deeply impressed oval or obcordate area, which is posteriorly situated and divisible into a narrow median adductor and broad lateral diductors, the surface of the latter being marked by radiating or racemose furrows. The posterior and anterior members of the diductors may frequently be distinguished, the former being of less extent and their sur- face markings somewhat different from those of the latter. A median septum in this valve is usually absent ; occasionally it is in a con- dition of incipient development, and in certain species having the aspect of Spiriferina and belonging to the line of descent of which this genus may be regarded as the final or accessory product, it forms a most conspicuous feature of the interior. In the brachial valve the umbo is inconspicuous, the apex only being in- curved over the cardinal area ; a median fold corresponds to the sinus of the opposite valve. The cardinal area is narrow and divided by a broadly triangu- lar delthyrium. The dental sockets are narrow, moderately deep and bounded interiorly by highly developed socket walls, the extremities of which support the crural bases. The cardinal process is a low, transverse, sessile apophysis, having its surface vertically striated; occasionally it is bipartite or it may be wholly resorbed. The crura are long, straight and slightly divergent ; their union with the primary lamellae of the spiral ribbon is at a broadly obtuse angle. The brachial BRACHIOPODA. 7 coils are directed outward and upward toward the cardinal angles of the valves and their variation in size and direction is in l^eeping with the differences in the marginal outline of the shell. The number of revolutions of the ribbon exceeds that in any other genus of brachiopods. There is no loop ; its position, however, is indicated by a pair of short spinous processes originating on the primary lamellae soon after their junction with the crura, and which are directed inward with a slight convergence. The muscular area has about the same extent as that of the pedicle-valve, though less distinctly impressed and generally more elongated. It is consti- tuted of two pairs of adductor impressions with their surfaces radiately or pal- mately striated. The anterior pair are central, narrow at their posterior ex- tremities which are embraced by the broader posterior scars. A faint median septum is sometimes present. In some instances of import- ance the socket walls are supported by septa which may be considerably pro- duced over the bottom of the valve. In both valves the genital region is distinctly punctated, but vascular mark- ings are rarely observed. Type, Anomites striatus, Martin (1809). Carboniferous limestone. Obsebvations. — Historical. This most prolific genus received its designation first in 1814, when its distinguished author, Mr. James Sowerby, read a com- munication before the Linnean Society entitled : " Some account of the spiral tubes or ligaments in the genus Terebratula, Lam., as observed in several species of fossil shells." The name was based upon the discovery of the spiral brachial supports in the species Anomites striatus, Martin. This contribution was not published until 1818 (Transactions of the Linnean Society, vol. xii, p. 514). Meanwhile, in the second volume of the Mineral Conchology (p. 42, 1815), Sow- erby published and described the genus, citing as the only example the Anomites cuspidatus, Martin. Davidson has shown* that the author's intention was still to regard A. striatus as the type, for appended to his paper in the Linnean Society's Transactions is the remark : " I suspect A. cuspidatus figured since the * Introduction to British Fossil Brachiopoda, p. 81, foot note. 8 PALEONTOLOGY OF NEW YORK. reading of this paper as Sp. cuspidatus, 'Min. Con.' tab. 120, * * * may have a siraihir construction within." A few writers have, with excellent reason, argued the application of the term to species congeneric with A. cuspidatus. Among these were Professor King (Monograph of the Permian Fossils of England, pp. 81, 126), and Mr. Meek (Palseontology of the Upper Missouri, p. 19), both of whom would have applied Koenig's term Trignotreta (1825) to spiriferoids of the type of A. striatus. It is, however, too late now to enforce the prior rights of A. cuspidatus to recogni- tion as the type of Spirifer. Winchell, in 1863, founded his genus Syringo- THYRis on a species (S. typa, Winchell) very similar to, if not identical with A. cuspidatus (according to King and Davidson),* and an inversion of the terms could only induce lamentable disorder in nomenclature.! It is a most surprising fact that a group of brachiopods with so remarkable a representation in species as this, should afford so unsatisfactory a basis for generic subdivision. Of the various names which have been proposed by dif- ferent authors but few can be advantageously applied. Trigonotreta was inti'oduced by Koenig, in 1825,J for a heterogenous assem- blage of species, consisting mainly of Spirifer and Orthis. King, in emending and adopting the term, selected the species Terebratula Stokesi, Koenig, as the type ; this appears to have been a form with plicated fold and sinus, and is, hence, a member of the typical division of the genus, the Aperturati. What- ever significance the term may have is derived from King's determinations, and Trigonotreta, King, is a precise equivalent for Spirifer striatus, Martin. Choristites, Fischer de Waldheim, 1825.§ This name was proposed by the Russian author to replace Sowerby's designation on the ground that the inter- nal organization described by the latter was common to all " the Terebratulas." The first species of the genus cited both in this place and in his later work, * Mr. Charles Schdchert regards W™chell's species as not equivalent to the Eng-lish form, but a synonym for Spirifer (Symigothyris) Carten, Hall. See Forty-third Kept. N. Y. State Museum, p. 232, 1890. t Professor King subsequently abandoned his position in this matter (Davidson, op. cit, p. 81), and it would appear from Mr. Meek's use of the term Spirifer in writings subsequent to 1864, that he also con- ceded the necessity for its adojition. t Icones Fossilium sectiles, p. 3. § Sur la Choriatite, p. 7. BRACHIOPODA. 9 " Oryctographie du Gouvernement de Moscou " (1830), is Choristites Mosquensis, Fischer {= Spirife.r Mosquensis, de Verneuil). The generic term was based upon the existence in the jjedicle-valve of highly developed dental plates extending almost or quite to the anterior margin ; a character which has a less prominent development in a few other species, some of which, as for example, Spirifer plicatellus, cannot be satisfactorily grouped with S. Mosquensis on the basis of external characters. The greater or less prolongation of these septa or dental lamellae will be found a feature of comparatively little taxonomic value among these fossils. Delthyris, Dalman, 1828.* Dalman divided the genus Spirifek into Del- THYRis and Cyrtia, citing as his first example of the former, Delthyris elevata, Dalman, a species now well known in the European Silurian, and one of the plicate-fimbriate members of the genus. The name Delthyris may, with a restricted interpretation, have a value equivalent to that of Reticularia, McCoy, under which the nonplicate-fimbriate species may be included. McCoy, in his " Synop.sis of the Characters of the Carboniferous Fossils of Ireland " (1844), proposed a number of new names to subdivisions of the family DeltbyridjE : Fusella {op. cit., p. 132); type, Spirifer fusif or mis, Vh.\\\vps; a small, transverse shell with smooth, rounded ribs, some of which are stated to occur on the me- dian fold. The species is but little known, Davidson statingf that he had seen only the imperfect original in the collections of the British Museum. Martinia (op. cit., pp. 128, 139). " Gen. Ch.- — Hinge-line shorter than the width of the shell ; dorsal edges of the cardinal area obtusely rounded ; surface smooth ; spiral appendages small." This group is excellently characterized, though McCoy was in error, as shown by Mr. Davidson and the Rev. Mr. Glass, in considering the spirals as having a less development in proportion to the dimensions of the shell than in other Spirifers. De Koninck, Davidson, Waagen and others have observed that the epidermal layer of the shell is minutely punctured. The first species which * Kongl. Vetenskaps Akad. Handlingar, pp. 93, 99. t British Carboniferous Brachiopoda, p. .57. 10 PALEONTOLOGY OF NEW YORK. was cited by McCoy among examples of Martinia, is Spirifer decorus, Phillips, a form closely allied to, and in the opinion of Mr. Davidson, identical with Mar- tin's Anomites (= Spirifer) glaber. Reticularia {op. cit., pp. 128, 142). First species cited, Terebratula imbricata, Sowerby = A?iomites lineatus, Martin = Spirifer lineatus of authors. Shells of this type have the short hinge and the smooth or gently plicated surface char- acterizing Martinia, and like the latter have neither dental plates nor septa on the interior. The name is based upon a species whose surface is covered with concentric fimbriae of doubled-barreled spines bearing single rows of lateral spinules,* and must probably be restricted to this type of exterior as in the more strongly plicated of the fimbriated Spirifers the surface spines are simple. Brachythyris {op. cit., pp. 128, 144). Proposed for short-hinged plicated species, the first cited being Spirifer duplicicosta, Phillips, a very close ally ex- ternally and internally of Spirifer striatus. Considering the great possibilities of variation among the Spirifers in the length of the hinge, it seems that this term must be considered a synonym for Spirifer in its strictest meaning. Martiniopsis, Waagen, 1883. f Type, Martiniopsis iiiflata, Waagen. Produc- tus limestone. These are non-plicated shells with smooth exterior and punc- tured epidermal layer, as in Martinia. The distinction from Martinia is based upon the existence of well developed dental plates in the pedicle-valve and septa supporting the crura in the brachial valve. Taxonomic. Whatever value any of the foregoing terms may possess, lies in the fact that it designates an extreme of accessory or lateral develojiment from a typical normal Spirifer stock. With a large amount of material affording the successive steps in these variations this value is, to the student, so palpably diminished that he hesitates to make use of any designation which excludes the term Spirifer. At the same time there are certain lines of development leading to definite resultants which it is necessary to regard as generically distinct from Spirifer * See figures Spirifer lineatus given by Mr. Davidson and Mr. John Todng, Supplement to British Car- boniferous Bi-achiopoda, pi. xxxiv, fig-. 9, and expl. of plate, foot note. 1880. t Salt-Range Fossils ; Brachiopoda, p. 524. BRACHIOPODA. 11 though losing none of its external characters. We may cite the apparent out- come of Spiriferina from the septate lamellose Spirifers ; and Syringothyris as the final product of changes along the line of those plicate Spirifers with smooth fold and sinus. Such changes, then, which we recognize as having induced actual generic differences are confined to the interior and the intimate structure of the valves ; external variations, as far as now known, when unaccompanied by internal changes, must be regarded as of altogether subordinate value. These external differences, however, make an excellent basis for a grouping of the members of this protean genus, and one not merely conventional and arbitrary, since it serves to indicate, within the integrity of the genus, lines of progress leading to resultants which are no longer congeneric. Several authors have proposed a classification of the Spirifers on the basis of their external ornamentation, and earlier writers were especially fond of attempts in this direction. Frequently the proposed arrangements have been vitiated by the inclusion within this genus of distinctly heterogeneous species. Thus with VON Buch's classification in 1836 and 1837,* and to some extent with that given by Phillips in 1836.t The latter writer proposed six subdivi- sions of his Spirifers: a. Cuspidate; h, Angustatcz ; c, Radiata; d, Glabrata ; e, Terehratuliformes; f, Filosce,. The list of species referred to the last two divi- sions contained no Spirifers, but Athyris (e) and Schizophoria, Orthothetes and Chonetes (f). The Cuspidate were typified by S. cuspidatus, and this group is equivalent, in a restricted sense, to the genus Syringothyris, though it was also made to include species of Cyrtia, Derbya and Orthothetes. The Angus- tat(B and Radiate were separated on the basis of the length of the hinge, which, in the former, equaled or exceeded the width of the shell. Both included species with smooth and plaited fold and sinus. The Glabrate included both Spirifer glober and S lineatus, that is, both Martinia and Reticularia. De Verneuil J divided the Spirifers as follows: \. Anormaux, mc\\\(\.mg the equirostres (== Porambonites) and bifores (= Platystrophia) ; II. Lisses, equiva- lent to Reticularia and Martinia, but embracing a species of Tkiplecia ; III. * Ueber das Genus Delthyris ; and Uebei- Deltliyris, oder Spirifer iind Orthis. t Illustrations of the Geology of Yorkshire. I Geologie de la Russie de I'Europe, p. 127. 1845, 12 PALAEONTOLOGY OF NEW YORK. Costes, subdivided into the costes (= Spirifer ?, Pentamerus ?) and costato-stries, the latter including a radiate species and Enteletes Lamarcki ; IV. Plisses, sub- divided into the aperturati, with sinus plicate, and ostiolati, with sinus smooth; terms which had already been proposed by von Buch, and were derived from Schlotheim's species, S. aperturatus and S. ostiolatus. QuENSTEDT, in 1871, adopted these last-named divisions and added the division Rostrati, for species in which the hinge-line is short; this chaotic assemblage was made to include the smooth species of the Palaeozoic (Martinia and Reticularia) as well as the Spiriferinas of the Carboniferous and Mesozoic. In the American Palaeozoic there are probably not less than two hundred species of the genus Spirifer. Representatives of the greater number of these have passed under our examination, and they, with the aid of not a few species unknown in American faunas, have furnished the evidence upon which the following proposed arrangement is based : I. Radiati. Typical example, Spirifer radiatus, Sowerby (including S. plicat- ellus, Sowerby). (I)* 1840. Delthyris, Conrad. Geol. Suvv. N. Y., Pal. Dept. ; Fourth Ann. Kept., p. 207. (1) 1842. Delthyris, Conrad. Journ. Acad. Nat. Sci. Phila., vol. viii, p. 261, pi. xiv, fig. 17. (2) 1842. Delthyris, Conrad. Journal Acad. Nat. Sci. Philadelphia, vol. viii, p. 261. (1) 1842. DeWiyr'is, Vandxem. Geology of N. Y. ; Kept. Third Dist, p. 120, tig. 1. (1) 1843. Spirifer, Ca.stelnad. Essai sur le Systfeme Silur. de I'Amer. Septen., p. 41, pi. xiii, fig. 5; p. 42, pi. xiii, fig. 4. (1) 1843. Delthyris, Mather. Geology of N. Y. ; Kept. First Dist., p. 343, fig. 1. (1) 1843. Delthyris, Hall. Geology of N. Y. ; Kept. Fourth Dist.. p. 105, fig. 2 a, b. (2) 1843. Delthyris, Hali.. Geology of N. Y. ; Rept. Fourth Dist., p. 105, fig. 1 ; p. 269, fig. 1. (3) 1847. Spirifer, Barrandb. Ueber die Brachiopoden der Silnr. Schicht. Bohmens. (1) 1852. Spirifer, Hall. Palajontology of N. Y., vol. ii, p. 66, pi. xxii, 2 d-s (not figs. 2 a-c, 2/) j p. 265, pi. liv, figs. 6 a-/. (2) 1852. Spirifer, Hall. Palaeontology of N. Y., vol. ii, p. 264, pi. liv, figs. 5a-f. (1) 1856. Spirifer, Billings. Canadian Naturalist and Geologist, vol. i, p. 135, pi. ii, figs. 2, 3. (2) 1856. Spirifer, Billings. Canadian Naturalist and Geologist, vol. i, p. 137, pi. ii, fig. 8. (1) 1859. Spirifer, Hall. Paleontology of N. Y., vol. iii, p. 202, pi. xxvii, figs. 1 a-f; pi. xxviii, figs. 8 a-d. (2) 1860. Spirifera, Emmons. Manual of Geology, p. 151. (1) 1861. Spinfei-a, Hall. Ann. Rept. Geol. Survey of Wisconsin, p. 25. 'S'j'm/era, Hall. Ann. Rept. Geol. Survey of 'Wisconsin, p. 26. Spirifera, McChesnet;. Palaeozoic Fossils, p. 84. Spirifera, Hall. Geol. Rept. Wisconsin, vol. i, p. 69, fig. 5 ; p. 436. Spirifera, Hall. Geol. Rept. Wisconsin, vol. i, p. 69, fig. 6 ; p. 436. •.The.parenthetical uumbers before the citations refer to the eabdivisions of the group. (3) 1861. (3) 1861. (1) 1862. (3) 1862. BRACHIOPODA. 13 (1) 1863. Spirifera, Halt.. Ti-ansactions of the Albany Institute, vol. iv, p. 211. (1) IStiS. Spirifer, Billings. Geology of Canada, p. 317, fig.s. 328 a, h ; p. 957, fig. 4m; and Proc. Portland Soc. Nat. Hist, p, 117, pi. iii, fig. 16. (2) 1863. Spirifer, Billings. Geology of Canada, p. 317, fig. 329. (1) 1866. Spirifer, Billings. Catalogue Silurian Fossils Aiiticosti, p. 48. (1) 1867. Spirifera, Hall. Twentielh Annual Report N. Y. State Cab. Nat. Ilistoi-y, p. 370. pi. xiii, tigs. 5, 7; p. 371, pi. xiii, figs. 9-11. (3) 1867. Spirifera, Hall. Twentieth Annual Report N. Y. State Cab. Nat. History, p. 372, pi. xiii, figs. 14-16. (2) 1867. Spirifera, Hall. PaliBontology of N. Y., vol. iv, p. 218, pi. xxxv, figs. 1-9; p. 242, pi. x1, fitjs. 14-22. (3) 1868. Spirifera, McChesney. Trans. Chicago Acad. Sci., vol. i, p. 35, pi. viii, fig. 3. (1) 1872. Spirifera, Hall. Twenty-fourth Ann. Kept. N. Y. State Mus. Nat. Hist., p. 182. (1) 1875. Spirifera, Hall and Whitfield. Twenty-seventh Ann. Rept. N. Y. State Mus. Nat. Hiat., pi. ix, figs. 11, 13, 17, 18. (1) 1879. Spirifera. Hall. Twenty-eighth Ann. Rept. N. Y. State Mus. Nat. Hist., p. 156, pi. xxiv, figs. 13-18 ; p. 157, pi. xxiv, figs. 20-30. (1) 1880. Spirifera. White. Second Ann. Rept. Indiana Bureau of Statistics and Geol., p. 497, pi. iii, figs. 5, 6. (1) 1881. Splrifei-a, White. Tenth Ann. Rep., Slate Geologist Indiana, p. 129, pi. iii, figs. 5, 6. (1) 1882. Spirifera, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 294, pi. xxiv, figs. 13-18 ; p. 296, pi. xxiv, figs. 20-30. (1) 1882. Spirifera, Whitfield. Geology of Wisconsin, vol. iv, p. 287, pi. xvii, figs. 1, 2. (2) 1885. Spirifera, Clakkb. Bull. U. S. Geol. Survey, No. 16, p. 30, pi. iii, fig. 13. (2) 1886. Spirifera, Ringuebbrq. Bull. Buffalo Soc. Nat. Hist., vol. v, p. 16, pi. ii, fig. 5. (1) 1889. /Spiri/er, Beecher and Clarke. Mem. N. Y. State Museum, p. 78, pi. vi, tigs. 9-11. (1) 1889. Spirifera, Nettelroth. Kentucky Fossil Shells, p. 117, pi. xxxii, figs. 28-31 ; p. 129, pi. xxiv, fig. 25 ; pi. xxvii, figs. 17-19 ; p. 130, pi. xxix, figs. 13-16. (1) 1890. Spirifera, Foerste. Proc. Boston Soc. Nat. Hist., vol. xxiv, p. 313, pi. v, tig.s, 5, 6. (2) 1891. Spirifer, Whiteaves. Contributions to Canadian Palseontology, vol. i, p. 224, pi. xxxii, tig. 1. Smooth, radially undulated or plicated; fold and sinus smooth; entire surface covered with fine, filiform, radiating striae, which may be minutely crenulated or granulose. This group includes shells which may vary considerably in the length of the hinge and the degree of plication. Spirifer radiatus is frequently, and in American faunas usually devoid of plications, but the assumption of these characters is so gradual a process that there is no satisfactory distinction, in a large number of examples, between the smooth form and the typical plicated form of S. plicatellus. The plications are, however, never numerous or sharply defined. These radiate shells may be conveniently subdivided as follows : 1. Pauciplicati, or those with few low plications; as Spirifer radiatus, Sowerby, S. Eudora, Hall, from the Clinton and Niagara faunas, and S. macropleura, Con- 14 PALEONTOLOGY OF NEW YORK. rad, from the Lower Helderberg group. Though this type is not abundantly developed in American faunas it embraces a very considerable number of the many forms described by Barrande* from the Bohemian etages E and F. Among these species the cardinal area has but an incipient development or may be altogether absent, while the dental plates are frequently quite pronounced. 2. Multiplicati, or those with numerous plications ; as Spirifer Niagarensis, Conrad, & asperatus, Ringueberg, of the Niagara group ; S. TulUa, Hall, of the Hamilton fauna ; S. Belphe.gor, Clarke, of the Genesee shales ; S. mesastrialis, Hall, of the Chemung group. In this group, with the more extended hinge and more abundant plications characterizing the Devonian and Carboniferous Spirifers generally, the radiate type of superficial structure has been maintained the longest. It is evident from material before us, that the type was continued into the faunas of the Lower Carboniferous. 3. Dupliciplicati. A few upper Silurian species have strong dichotomous plications and the filamentous surface striae covered with asperities. Such are Spirifer nobilis, Barrande, from the etage E^, and the Niagara limestone of Illinois and Wisconsin, and S. Schmidti, Lindstrom, from the Gotland lime- stone. The Radiati generally may be said to have prevailed at an early period in the history of the genus. The combination was one that was but little modi- fied during its existence and was involved in no progressive development of generic characters. II. Lamellosi. Typical examples, Spirifer perlatnellosus, Hall, S. mucronatus, Conrad. (2a) 1820. Ta-ebratula, Atwater. Amei-. Joui-. Sci. and Arts, vol. ii, p. 224, pi. i, figs. 2, 3. (2a) 1841. Delthyns, Conkad. Geol. Survey N. Y., Pal. Dept. ; Fifth Ann. Kept., p. 54. (1) 1842. DeUhyris, Conrad. Joui-. Acad. Nat. Sci. Philadelphia, vol. viii, pp. 261, 262, pi. xiv, fig. 18. (1) 1842. DeUhyris, Vanuxem. Geology of N. Y. ; Kept. Third Dist., p. 132, fig. 3. (2a) 1842. DeWiyris. Vanuxem. Geology of N. Y. ; Kept. Third Dist., p. 150, fig. 3. (1) 1843. Ddthyns, Hall. Geology of N. Y. ; Kept. Fourth Dist., p. 105, fig. 4 ; p. 2U0, fig. 5 ; pp. 202, 269, tig. 9 ; p. 270, fig. 5. (2a) 1843. DeUhyris, Hall. Geology of N. Y. ; Kept. Fourth Dist., p. 198, figs. 2, 3 ; p. 205, fig. 32; p. 270, fig. 3. (2a) 1843. Spirifer, Castelnau. Essai sur le Systeme Silur. de I'Amer. .Septentr., pi. xiii, fig. 1. ' Sysleme Silurien du Centre de la Boheme, vol. v, i)Is. i-viii. BRACHIOPODA. 15 (1) 1849. S^nfifer, Hall. American Journal of Science, vol. xx, p. 2:iS. (1) 1852. Spinfei; Hall. Palaeontology of N. Y., vol. ii, p. 261, pi. liv, fig-. 2. (1) 1856. Spirifer, Billings. Canadian Naturalist and Geologist, vol. i, p. 137, pi. ii, fig. 7. (2a) 1856. Spirifera, Billings. Canadian Nalui-alist and Geologist, vol. i, ]). 474, pi. vii, tigs. 9, 10. (1) 1857. Spirifer, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., p. 57, tigs. l-."). (2a) 1857. Spirifer, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 130, 131. (26) 1857. Spirifei; Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist , pp. 62, 63, 134. (1) 1858. Delthyris, Rogers. Geology of Pennsylvania, vol. ii, p. 825, tig. 643. (2a) 1858. Spirifer, Hall. Geol. Survey of Iowa, p. 507, pi. iv, figs. 6 b, c, d; p. 501, pi. iv, ligs. 3a-c. (1) 1859. Spirifer, Hall. Palaeontology of N. Y., vol. iii, p. 201, pi. xxvi, figs. 1, 2. (26) 1859. Spirifei; Hall. Palieontology of N. Y., vol. iii, p. 419, [)1. xcvi, fig.s. 7 a-/; p. 421, pi. xcvi, tigs. 9 a-g. (1) 1860. Spirifer, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 94. (26) 1860. Spirifer. Meek. Proc. Acad. Nat. Sci. Philadelphia, vol. iv, j). 308. (1) 1860. Spirifer, Hall. Canadian Naturalist and Geologist, vol. v, p. 145. (1) 1861. Spirifera, Billings. Canadian Journal, vol. vi, p. 258, figs. 71-73. (2a) 1861. Spirifera, Billings. Canadian Journal, vol. vi, pp. 254, 255, figs. 59-64. (2a) 1862. Spirifer, A. Winchell. Proc. Acad. Nat. Sci. Philadelphia, vol. xiv, p. 405. (1) 1863. Spirifera, Billings. Proc. Portland Soc. Nat. Hist., vol. i, p. 117, pi. iii, fig. 17. (1) 1863. (Spirjfera,, Billings. Geology of Canada, p. 372, fig. 392 ; p. 386, fig. 423; p. 957, fig. 455. (2a) 1863. Spirifera, Billings. Geology of Canada, p. 960, fig. 467; p. 386, fig. 424 «-d. (2a) 1866. Spirifera, A. Winchell. Rept. Lower Peninsula of Michigan, p. 93. (1) 1867. Spirifera, Hall. Pah-eontology of N. Y., vol. iv, pp. 192, 221, 222, 240, pi. xxvii, figs. 30-34 ; pi. XXX, figs. 1-9 ; pi. XXXV. figs. 10-23 ; pi. xl, figs. 1-13. (2a) 1867. Sinrifem, Hall. Palaeontology of N. Y., vol. iv, p. 205, pi. xxxi, figs. 1-4 ; p. 207, pi. xxxi, figs. 14-19; p. 208, pi. xxxi, figs. 9, 10; p. 216, pi. xxxiv, figs. 1-32. (26) 1867. Spirifera, Hall. Pateontology of N. Y., vol. iv, p. 190, pi. xxvii, figs. 18-28. (1) 1868. Spirifera, Meek and Worthen. Geological Survey of Illinois, vol. iii, p. 384, pi. vii, fig. 9. (1) 1871. Spirifera, Nicholson. Palaeontology of Province of Ont.ario, p. 82. (16) 1874. Spirifera, Nicholson. Palaeontology of Pi-ovince of Ontario, p. 80. (1) 1874. Spirifera, Billings. Palajozoic Fossils, vol. ii, p. 47, pi. iii a, fig. 5. (26) 1876. Spirifer, Mf.ek. Simjison's Rept. Expl. Great Basin Utah, p. 346, pi. i, fig. 1. (26) 1877. Spirifer, Meek. King's Rept. Expl. Fortieth Parallel, vol. iv, p. 41, pi. iii, fig. 3. (1) 1878. Spirifera, Dawson. Acadian Geology, third ed., p. 576. (1) 1882. Spirifera?, Whitfield. Geology of Wisconsin, vol. iv, p. 333, pi. xxv, figs. 23, 24. (2a) 1882. Spirifera, Whitfield. Geology of Wisconsin, vol. iv, p 328, pi. xxv, figs. 27, 28. (1) 1883. Spiriftra, Hall. Second Report N. Y. State Geologist, pi. lix, figs. 9, 27-34 ; pi. Ix, figs. 1-18. (1) 1884. Spirifera, Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 135, pi. iv. fig. 2 ; pi. xiv, fig. 12. (2a) 1884. Spirifera, yifALCOTT. Palaeontology Eureka Dist., pp. 136, 217, pi. vn, fig. 8. (1) 1889. Spirifera, Nettelroth. Kentucky Fossil Shells, pp. 128, 132, pi. xvii, figs. 38-42 ; pi xxxi, fig. 13. (26) 1889. Spirifera, Nettelroth. Kentucky Fossil Shells, p. 112, pi. xii, figs. 1-4. (2a) 1889. Spirifera, Nettelroth. Kentucky Fossil Shells, p. 134, pi. x, .figs. 11-20, 23-25 ; p. 109, pi. X, figs. 1-5, 31-34, 36-39 ; p. 121, pi. x, figs. 21, 22, 26-30, 35, 40 ; p. 108, pi. xii, figs. 14, 15; p. 132, pi. xiii, figs. 36, 38; p. 126, pi. xxxi, figs. 10, 11. (2a) 1891. Spirifera, Whiteavbs. Contribulions to Canadian Palfeontology, vol. i, p. 223. Rcadically plicated ; surface covered with numerous concentric lamellae. In Silurian species the fold and sinus are non-plicate ; the later forms usually 16 PALEONTOLOGY OF NEW YORK. bear a low median depression on the fold accompanied by a corresponding median ridge in the sinus. In this division we meet with considerable diversity in exterior form, the hinge being at times short, and again extremely extended ; always, however, making the greatest diameter of the shell. The cardinal area is usually low, but may be considerably elevated. The species all have a fine, very faintly developed median ridge in the interior of the brachial valve and the cardinal process developed as a low, single, multistriate apophysis, with sometimes a tendency to bilobation. The lamellose species are conveniently subdivided into two groups : 1. Septati; those having a median septum in the pedicle-valve. The septum lies between the bases of the teeth but does not come into contact with them as in the genus Cyrtina, where the latter are supported by dental lamellae rest- ing on the bottom of the valve. This character is found in an incipient condition of development in the Niagara species Spirifer sulcatus, Hisinger, and is a more conspicuous feature in subsequent forms, S. perlamellosus, of the Lower Helderberg, S. raricosta, of the Upper Helderbex'g, S. consohrinus* of the Hamilton group and S. mesacostalis, of the Chemung group. Up to the period of the upper Devonian, at least in Amer- ican faunas, the existence of this septum in the pedicle-valve is not accompanied by a punctation of the shell-tissue, nor by the union of the processes on the pri- mary lamellae of the spiral arms; features which characterize the genus Spirifek- INA, and, indeed, form the only basis of distinction between some of the paljBOzoic members of this genus and these septate Spirifers. At present we are without evidence of the gradual assumption of punctation by shells in this line of development, but there can be no reason to doubt that its appearance here was of the same nature as along the line leading from Spirifer to Syringothyris,! gradual or sporadic. * This is the species desci-ibed as Spirifer zie-zac, Hall, in 1843. The same specific name was, curiously enough, used by F. Roemer, in the same year, for a quite distinct Devonian Spiripeb, and D'Orbignt, in 1850, proposed for the Ameiican species the name above used. t See observations on the genera Syringothtri.s, Cyrtina and Spiripbrina. BRACHIOPODA. 17 Mr. Davidson has referred two Devonian species to Spiriferina, 8. cristata Schlotheini, var. odoplicata, and S. insculpta, Phillips ( ? ), both of Avhich are described as having a punctate structure. It is not known, however, whether in these early forms the loop has attained its ultimate development; Ave might expect to find it with its lateral branches discrete as in the true Spirifers. The species of this septate section have, so fiir 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. Kentuckiensis and S. solidirostris, which resemble very closely in other respects these septate lamellose Spirifers, are fimbriated. •J 2. 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, maltijjlicate shell with a single low plication in the sinus and a corresponding depression on the median fold ; the other, (b), Spirifer submucronatus, 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. Cumberlandicz, Hall, of the Oriskany sandstone of Maryland, S. macrus, Hall, S. gregarius, Clapp, and an undescribed species from the Upper Helderberg group. Spirifer gregarius 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 S. mucronatus, S. segrnentus. Hall, S. bimesialis. Hall, S. subat- tenuatus. Hall, S. varicosus, Conrad. III. FiMBRiATi. Typical examples, Spirifer fimbriatus, Conrad, S. lineatus, Martin, S. arrectus, Hall. (la) 1842. Orthls, Vanoxem. Geology of N. Y. ; Rej>t. Third Dist., ]i. 112, figr. 1. (16) 1842. 0)77hs, Vanuxem. Geolog-y of N. Y. ; Kept. Third Dist., i>p. 91, 94. (16) 1859. (2) 1860. (lo) 1861. (2) 1861. (2) 1862. (It) 1863. (In) 1863. (In) 1863, 18 PALEONTOLOGY OF NEW YORK. (2) 1842. DeWiyris, Conrad. Jour. Acad. Nat. Sci. Philadelphia, vol. viii, p. 263. (la) 1843. Orthis ? {Delthyris}, Ui^hh. Geology of N. Y. ; Rept. Fourth Dist., p. 142, fig. 1. (la) 1843. DeUhyris, Hall. Geology of N Y. ; Kept. Fourth Dist., p. 105, fig. 3; p. 171, fig. 5. (16) 1843. DeUhyris, Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 208, fig. 10 ; ]>. 345, fig. 1. (la) 1843. Spirifer, Castelnau. Essai surle SystemeSilur. de I'Amer. Septentr., p. 41, pi. xii. figs. 1, 2. (In) 1849. >'ipirifer. Hall. American Journal of Science, vol. xx, p. 228. (In) 1852. fSpirifm; Hall. Pal.-pontology of N. Y., vol. ii, p. 262, pi. liv, figs. 3rt-t; ].. 328, pi. Ixxiv, figs. 9 a-?i.. (16) 1852. Spirifer, Hall. Paleontology of N. Y., vol. ii, p. 263, pi. liv. fig. 4. (2) 1853. Spirifer, Swallow. Trans. St. Louis Acad. Science, vol. ii, p. 86. (la) 1857. Spinfer, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., pp. 58, 62. (2) 1858. Spirifer, Hall. Geol. Survey Iowa, vol. i, pt. ii, p. 505, pi. iv, figs. 5a-e; p. 645, pi. xx, fig. 4 ; p. 705, pi. xxvii, fig. 4. (In) 1859. Sjnrlfn: Hall. Paleontology of N. Y., vol. iii, p. 420, pi. xcvi, figs. 8 a-e ; p. 422, pi. xcvii, figs. la-A, 2o-J; p. 205, pi. xxviii, figs. 4 a-e; p. 199, pi. xxv, figs, lo-z; p. 203, pi. xxviii, figs. 2 a-/; p. 198, pi. viii, figs. 17-23. Spirifer, Hall. Paljeontology of N. Y., vol. iii, p. 203, pi. xxviii, fig. 1. Sjnrifer, McChesney. New Paleozoic Fossils, p. 43. S2}lrifera, Billincs. Canadian Journal, vol. v, p. 256, figs. 65-67. Spirifera, Billings. Canadian Journal, vol. v., p. 257, figs. 68-70. Spirifera, White and Whitfield. Proc. Boston Soc. Nat. Hist., vol. viii, p. 116, pi. iii, fig. 15. Spirifera, Billings. Pi-oc. Portland Soc. Nat. Hist., vol i, p. 116, pi. iii, fig. 15. Spirifera, Hall. Ti-ansactions of the Albany Institute, vol. iv, p. 212. Spirifera. Billings. Geology of Canada, p. 372, figs. 394 a, 6, <•; p. 960, fig. 466 ; p. 957, fig. 457. (la) 1867. Spiiif era. Hall. PaliEontoIogy of N. Y, vol. iv, p. 189, pi xxvii, figs. 13-16; pi. xxviii, figs. 24-33. Spirifera, Hall. Paleontology of N. Y., vol. iv, p. 239, pi. xxxix, figs. 1-12. *S'pj)-i/ern, Hall. Paleontology of N. Y., vol. iv, p. ;214, pi. xxxiii, figs. 1-21; p. 250, jil. xxxiii, figs. 31-35. Spirifer, Meek and Worthen. Geol. Sui'vey Illinois, vol. iii, p. 434, pi. x, figs. 5 a-e. Spirifera, Meek and Worthen. Geol. Survey Illinois, vol. iii, p. 399, pi. viii, figs. 6a-rf, figs. 7 a, h. Spirifera, Billings. Paleozoic Fossils, vol. ii, p. 48, pi. iii A, figs. 4, 4 c. Spirifera, Hall. Twenty-eighth Ann. Rept. N. Y. State Mus., p. 157, pi. xxiv, figs. 6-12, 19. Spirifera, Rathbun. Proc. Boston Soc. Nat. Hist., vol. xx, p. 25. Spirifera, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 295, pi. xxiv, figs. 6-12, 19. Spirifera, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 297, pi. xxvii, figs. 8, 9. Spirifera (Martinia), White, Thirteenth Annual Report State Geologist of Indiana, p. 133, ^il. xxvii, figs. 4-6. (2) 1884. Spirifera [Martinia), ViALCOTT. Paleontology Eureka Dist., jip 143-145, pi. iii, figs. 3, 6 ; pi. xiv, fig. 11. (16) 1888. Spirifera, Calvin. Bull. Laboratories University of Iowa, p. 28. (la) 1889. >Spiri/eca, Nkttelroth. Kentucky Fossil Shells, p. 114, pi. xii, figs. 12, 13, 16; p. Ill, pi. xvii, figs. 36, 37. (la) 1889. Spirifer, Beechbr and Clarke. Mem. N. Y. State Mus., vol. i, No. 1, p. 75, pi. vi, figs. 4-7. (la) 1891. Spirifera, Whitfield. Annals N. Y. Acad. Science, vol. v, p. 509, pi. v, figs. 4, 5. Shells with few low plications or none ; hinge line not greatly extended, often shorter than the greatest diameter of the shell ; dental lamellae moderately, (16) 1867. (2) 1867. (2) 1868. (la) 1868. (la) 1874. (la) 1879. (la) 1879. (la) 1881. (16) 1882. (2) 1884. BRACHIOPODA. 19 sometimes notably developed ; a low median septum may exist in the pedicle- valve. Surface covered with concentric rows or fringes of fine spines. This group is susceptible of the following subdivision : 1. f/m'dspwu'/ = Delthyris, Dalman, 1828, sensu striclo ; those species in which the concentric fimbriae are made up of short, simple, hollow spines. Those are the early fimbriate species, the type of structure not extending, so far as now known, beyond the Devonian. The shells are distinguished from the other fimbriate Spirifers by their more extended and more distinctly pli- cated surface and the prominent, often sharply developed fold and sinus. Their more characteristic representatives in the American Palaeozoic are Spirifer crispus, Hisinger, and v;i,r. simplex, Hall, of the Niagara fiiunas; tS. Vmiuxemi, Hall, of the Tentaculite limestone, S. Safordi, S. odocostatus, Hall, of the Lower Helderberg group, S. arredus, S. tribulis, Hall, of the Oriskany sandstone and S. duodenarius. Hall, of the Corniferous limestone. This may be termed the (a) S. crispus-type. An interesting series of forms which has had a parallel development with the iS. crispus-type begins with the S. bicostatus, Vanuxem, and var. peiilus, Hall, in the Niagara group, is represented by S. modestus. Hall, in the Lower Helderberg group, by a new species, S. Canandaigua* from the Hamilton group of New York, and possibly, S. urbanus, Calvin, from a corresponding horizon in Iowa, the line terminating in (b) S. laevis. Hall, from the lower Portage shales at Ithaca, N. Y. These are all unicispinate, but have the short hinge, subcircular outline and obsolescent plications characterizing the duplicispinate group of the FiMBRiATi. It is important to observe that this little series has, with reference to the main line of development of these forms, an expression of immaturity, the low plications and short hinge being features indicative of such a condition among those species.f With the exception of S. laevis, all the members of this subordinate group (the S. Zams-type) are quite small ; the Portage species, how- ever, is one of the largest of fimbriate Spirifers, while its development, though abundant in individuals, is sharply localized. It stands out prominently as a * Kor description of this species see Supplement to this volume. t See observations on, and illustrations of Spirifer bicosiatas and var. peliliui, and young of S. crispus and var. simplex, in Memoirs New York State Museum, vol. i, No. 1, pp. 75-77, pi. vi, figs. 1-7. 1889. 20 PALEONTOLOGY OF NEW YORK. strong senile development of a disappearing type. It has already been re- marked that the term Delthyris, Dalman, may properly be restricted to the unicispinate Fimbriati. The name was applied to species of which S. elevatus, Dalman, was the first and typical member, a form not unlike S. crispus, Hisinger, and from faunas of the same age. 2. Duplicispinei = RETKVLAniA, McCoy, 1844; those species in which the fimbriae are composed of large, compound, hollow spines, often or always with lateral branches. Each spine is divided medially by a vertical septum, and along this line the spine is depressed exteriorly, giving it a double-barreled appearance ; from each lateral margin are given off at regular intervals short spinules at right angles to the main spine. This peculiar structure was first described by Mr. Davidson, in 188U, from its discovery by Mr. John Young in the Carboniferous species, S. Uneatus, Martin. It had been observed by us some years earlier than this in the species S. fimbriatus, Conrad, of the Hamilton group, and upon the accompanying plates are illustrations of this species showing it. The scar left by the removal of the spines is elongate-oval or lachrymiform, divided medially by the base of the vertical lamella. In addition to this surface ornament the members of this subdivision are well characterized by their shortness of hinge, which does not equal the greatest transverse diameter of the shell, the low cardinal area, the usual obsolesence or absence of radial plications and even of median fold and sinus, and the presence of concentric striations or ridges serving as bases for the fimbriae. Of this group Spirifer fimbriatus, Conrad, is the earliest representative, a form quite remarkable in its vertical range, appearing in the Oriskany sand- stone and in the succeeding faunas of the Schoharie grit, Corniferous limestone, Hamilton shales and Chemung sandstones. This species and S. subundiferus. Meek and Worthen, of Hamilton age, have more of the typical spiriferoid aspect in their well developed fold and sinus and low plications ; in these respects they afford a variation from the later members of the group, which is naturally to be expected in the earliest representatives of a type of structure. The group is, on the whole, possessed of very persistent and stable characters, BRACHIOPODA. 21 and its Carboniferous members have an expression so distinct from that of the normal Spirifer that many authors, among them Davidson and Waagen, have admitted McCoy's term Reticularia with the vakie of a genus. With the evidence before us we are unable to accord this group a higher value than that assigned to the divisions of the Radiati, the Ostiolati and the Glabrati ; a line of development which to all appearances terminated with palaeozoic time. To this second division of the Fimbriati belong the following American species : S. fimbriatus, Conrad, S. subundiferus, Meek and Worthen, of the Hamilton group, S. hirtus, White and Whitfield, of the Choteau limestone, S. pseudolineatus. Hall, of the Kinderhook and Keokuk groups, .S. seiigerus, Hall, of the St. Louis and Chester groups, S. clarus, Swallow, of the Chester group, S. lineatus, Martin, and S. perplexus, McChesney, of the Coal Measures. IV. Aperturati. Typical examples, S. aperturatus, Schlotheim, S. disjundus, Sowerby, S. striatus, Martin. (6) 183(n. Spirifer, Morton. Amei-ii-an Journal of Science and Arts, vol. xxix, p. 150, jjl. ii, fig-. 3. (a) 1839. Deini/ris, Conkad. Geol. Survey N. Y. ; Pal. Dept. ; 'i'hiid Aiui. Rept., p. 65. (a) 1841. Delthyvis, Conrad. Geol. Survey N. Y. , Pal. Dept. ; Fifth Ann. Kept., p. 54. (o) 1842. Delthyris, Conkad. Jour. Acad. Nat. Sci. Philadelphia, vol. viii, p. 263. (a) 1842. Delthyris, Vanuxem. Geology of N. Y. ; Rept. Third Dist., p. 179, fig-. 3 ; p. 123, Hg. 1 ; p. 12-1, fig. 5. (a) 1843. DeltJiyns,Hki.h. Geology of N. Y. ; Rept. Fourth Dist., pi). 269, .270, figs. 1-4 ; p. 148, fig. 1. (a) 1843. Delthyris, Mather. Geology of N. Y. ; Rept. Fir.st Dist., p. 342, fig. 1. (h) 1852. Spirifer, Owen. Geol. Survey Wisconsin, Iowa and Minnesota, p. 586, pi. v, tig. 6. (6) 1852. Spirifer, F. Roemer. KreidebiMung von Texas, p. 88, pi. xi, fig. 7. (6) 18.52. Spirifer, Hall. Stansbnry's Expl. Great Salt Lake, p. 410, pi. iv, fig. 5. ((■) 1854. Spirifer, Norwood and Pratten. Jour. Acad. Nat. Si-i. Philadelphia, second ser., vol. iii, p. 73, pi. ix, fig.s. 3a-e. {e) 1854. Spirifer, Norwood and Pratten. Joui-. Acad. Nat. Sci. Philadelphia, second ser., vol. iii, p. 72, pi. ix, figs. 2 a-c. (6) 1855. Spirifer, Shumard. Rept. Geol. Survey Missouri, p. 203, jil. c, tig. 8. (b) 1856. Spirifer, Hall. Expl. and Survey for R. R. Route from Missouri to the Pacific, vol. iii,- p. 102, pi. ii, figs. 9, 12. (e) 1857. Spirifer, Hall. Ti-ansactions of the Albany Institute, vol. iv, p. 8. (c) 1857. Spirifer, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 127. {/) 1857. Spirifer, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., ]>. 133. (o) 1858. Spirifei; Hall. Geol. Survey Iowa, p. 502, pi. iv, fig. 2. (la) 1858. Spirifei; Hall. Geol. Survey Iowa, p. 501, pi. iv, figs. 1 a-k. (6) 1858. Spirifer, Hall. Geol. Snrvey Iowa, vol. 1, pt. ii, p. 647, pi. xx, fig. 7 ; pi. xxi, figs. 1, 2 ; p. 604, pi. xiv, figs. 1-5 ; p. 641, pi. xx, fig. 1 ; p. 501, pi. vi, fig. 1 ; p. 709, pi. xxviii, tig. 2. (6) 1858. Spirifer, Marcou. Geology of North America, p. 49, jil. vii, fig. 2. 22 PALAEONTOLOGY OF NEW YORK. (r) 1858. Spirifer, Hall. Geol. Survey Iowa, vol. i, pt. ii, p. .')19, pi. vii, fig. 5 ; p. 600, pi. xiii. fig. I ; p. 601, pi. xiii, fig-. 2; p. 602, pi. xiii, fig. 3; p. 661, pi. xxiii, fig-. 1 ; p. 662, pi. xxiii, fig. 8 ; p. 663, pi. xxiii, fig. 9. (d) 1858. Spinfer, Hall. Geol. Survey Iowa, vol. i, pt. ii, p. 521, pi. vii, fig. 8 ; p. 644, pi. xx, fig. 3 ; p. 660, pi. xxiii, fig, 6 ; p. 676, pi. xxiv, fig. 4 ; pp. 706-708, pi. xxvii, fig. 6. (e) 1858. Spir'ifer. Hall. Geol. Survey Iowa, vol. i, pt. ii, p. 711. (e) 1858. Spirifer, Mabcod. Geology of North America, p. 50, pi. vii, fig. 4. (a) 1859. Spirifer, Hall. Palaeontology of N. Y., vol. iii, p. 425, pi. xcviii, figs. 1-8 ; pi. xdx, figs. 1-10 ; pi. c, figs. 1-8. (a) 1859. DeWiyris, Rogers. Geology of Pennsylvania, vol. ii. pt. ii, p. 829, fig. 683 ; p. 826, fig. 650. (b) 1860. Spirifer, Swallow. Trans. St. Louis Acad. Science, vol. i, p. 643. (e) 1860. Spirifera, McChesney. New Palaeozoic Fossils, p. 44. (/) 1860. Spirifer, Hall. Thirteenth Ann. Kept. N. Y. State Cab. Nat. Hist., p. 82. (6) 1861. Spirifer, Newberry. Ives' Rept. Colorado River of the West, p. 127. (a) 1863. Splrifera, Billings. Geology of Canada, p. 960, fig. 465. (e) 1863. Splrifera, Davidson. Quarterly Journal Geol. Soc. London, vol. xix, p. 171, jil. ix, figs. 7, 8. (e) 1865. Splrifera, A. Winchell. Proc. Acad. Nat. Sci. Philadelphia, p. 118. (b) 1866. Spirifer, Geinitz. Carbon und Dyas in Nebraska, p. 44. (e) 1866. Spirifer, Swallow. Trans. St. Louis Acad. Science, vol. ii, pp. 409, 410. (a) 1S67. Splrifera, Hall. Palieontology of N. Y., .vol. iv, p. 243, pi. xli, figs. 1-19 ; pi. xiii, figs. 1-20 ; p. 203, pi. xxx, fig. 21. (e) 1867. Splrifera, Hall. PaltEontology of N. Y., vol. iv, p. 194, pi. xxvii, fig. 29 ; pi. xxviii. figs. 7-23. (/) 1867. Splrifera, Hall. Palaiontology of N. Y., vol. iv, p. 213, pi. xxxii, figs. 1-6. (e) 1868. Splrifera, McChksnby. Ti-ans. Chicago Acad. Science, vol. i, p. 35, pi. i, fig. 4. (b) 1870. Spirlfeiu, Meek and Worthen. Proc. Acad. Nat. Sci. Philadelphia, vol. xvii, p. 36. Spirifer, A. Winchell. Proc. Amer. Philos. Soc, vol. xii, p. 252. Spirifer (Trlgonolreta?), Meek. Proc. Acad. Nat. Sci. Philadelphia, vol, xviii, p. 179. Spirifer, Meek. Palaeontology Eastern Nebraska, p. 183, pi. vi, fig. 12; pi. viii, fig. 15. Spirifer, Meek and Worthen. Geol. Survey Illinois, vol. iii, p. 573, pi. xxv, fig. 7. Splrifera. Hall and Whitfield. Twenty-third Ann. Rept. N. Y. State Cab. Nat. History, p. 237, pi. xi, figs. 16-20. Splrifera, Billings. Palfeozoic Fossils, vol. ii, p. 45, pi. iii a, fig. 3. Spirifii-a, Derby. Bull. Cornell University, vol. i, No. 2, p. 12, pis. i, ii, iv, v. (e) 1874. Splrifera, Derby. Bull. Cornell University, vol. i. No. 2, p. 15, pis. i, ii, iv. (6) 1875. Splrifera, White. Rept. Geogr. Surveys West 100th Meridian, p. 88, pi. v, fig. 10 ; p. 132, pi. X, fig. 1. (6) 1875. Splrifera (Trlgonot.reta), Meek. Paleontology of Ohio, vol. ii, p. 280, pi. xiv, fig. 8. (h) 1875. Splrifera, Meek and Worthen. Geol. Survey Illinois, vol. vi, p. 521, pi. xxx, fig. 3. (c) 1875. Splrifera (Trlgonolreta), Meek. Palaeontology of Ohio, vol. ii, p. 290, pi. xiv, fig. 5. (c) 1875. Splrifera, White. Rept. Geogr. Surveys West 100th Meridian, p. 86, pi. v, fig. 8. (d) 1875. Splrifera, Meek and Worthen. Geol. Survey Illinois, vol. vi, p. 523, pi. xxx, fig. 1. (e) 1875. Splrifera (Trigonotreta), Meek. Palaeontology of Ohio, vol. ii, p. 329, pi. xix, fig. 14. (e) 1875. (Spin/era, White. Rept. Geogr. Surveys West 100th Meridian, p. 134, pi. xi, fig. 9. (b) 1876. Spirifer, Meek. Simpson's Rept. Exi>l. Great Basin of Utah, p. 353, pi. ii, fig. 3. (b) 1876. Spirifer (Trigonotreta), Meek. Macomb's Rept. Expl. from Sante Fe to the Colorado, p. 139, pi. iii, fig. 5. (e) 1876. Splrifera, Meek. Bull. U. S. Geol. Survey, vol. ii. No. 4, p. 355, pi. i, fig. 3. (b) 1877. Splrifera, Hall and Whitfield. Geol. Expl. Fortieth P.arallel, vol. iv, p. 269, pi. v, figs. 13-15. (/)) 1877. Spirifer (Trigonotreta), Meek. Geol. Expl. Foi-tieth Parallel, vol. iv, p. 91, pi. ix, fig. 2. (v) 1877. Splrifera, Hall and Whitfield. Geol. Expl. Foi-tieth Parallel, vol. iv, p. 254, pi. iv, figs. 5, 6 ; p. 255, pi. iv, figs. 7, 8. (&) 1870. (h) 1871. (!>) 1872. H>) 1873. («) 1873. (a) 1874. (/) 1874. BRACHIOPODA. 23 (e) 1877. Spirifer (Trlgonotreta), Mekk. Geol. Expl. Fortieth Parallel, vol. iv, j>. 88, pi. ix, fig. 6. (fc) 1878. Spirifera, Haktt. Dawson's Acadian Geology, 3d ed., p. 300. (e) 1878. Spirifer, Dawson. Acadian Geology, 3d ed., p. 292, tig. 91. (6) 1881. Spirifera, Miller. Joui'nal Cincinnati Soc. Nat. Hist., vol. iv, p. 2. (e) 1882. Spirifera, Whitfield. Bull. Amer. Mus. Nat. Hist., vol. i, No. 3, p. 47, pi. vi, figs. 13-15. (d) 1883. Spirifera, yfaiTK. Twelfth Ann. Rep. U. S. Geol. Survey, p. 165, pi. xl, fig. 2. (e) 1883. Spirifera, Hall. Twelfth Rept. State Geologist Indiana, ]). 32G, pi. xxix, figs. 13-15. (a) 1884. Spirifera, Walcott. PaUBontology of the Eureka District, p. 134. (b) 1884. Spirifera, White. Thirteenth Rept. State Geologist Indiana, p. 132, pi. xxxv, Hgs. 3-5. (f) 1884. Spiriftra, Walcott. Pal:eontology of the Eureka District, p. 21(5, pi. xviii, figs. 4,7. (h) 1887. Spirifera. Herrick. Bull. Denison University, vol. ii, p. 45, pi. ii, fig. 22. (e) 1887. Spirifera, Herrick. Bull. Denison University, vol. i, p. 44, pi. ii, fig. 23. (6) 188!<. Spirifer, Herrick. Bull. Denison University, vol. iii, p. 44, pi. iii, fig. 26 ; pi. vi, tigs. 6-7 j vol. iv, pi. vii, fig. 2. (c) 1888. Spirifer, Herrick. Bull. Denison University, vol. Iv, p. 25, pi. ii, fig. 8. (b) 1889. Spirifera, Nettelroth. Kentucky Fossil Shells, p. 124. (/) 1889. Spirifera, Nettelroth. Kentucky Fossil Shells, p. 113, pi. xi, figs. 6-11 ; pi. xii, figs. 5-11. (e) 1889. Spirifera, Nettelroth. Kentucky Fo.'sil Shells, p. 120, pi. ix, figs. S-14. (b) 1890. Spirifera. Wdrthen. Geol. Survey Illinois, vol. viii, p. 105, pi. xl, tig. 5. {a) 1891. Spirifera, Whiteaves. Contributions to Canadian PaU-eontology, vol. i, p. 221, pi. xxix, tigs. 4, 5. Forms with plications on the fold and sinus. This may be regarded as the typical group of Spirifers as it includes the type-species S. striaius, Martin. Furthermore it is the most richly represented in species and at the same time is a most compact association, not presenting any substantial variations. Its members are strongly impressed with the typical spiriferoid characters which are maintained throughout its existence, the group terminating abruptly at the close of palaeozoic time. In internal structure variations are slight and unimportant. The dental lamellaB are, as a rule, in- considerably developed, and there is no median septum in either valve. Spirifer {= Choristiies) Mosquensis, Fischer, is an example of a very few medio- plicate species which have the dental plates highly developed; but in its closest ally in exterior characters, N. Grimesi, Hall, these are comparatively inconspicuous. The external ornamentation, the arrangement of the plications and the nature of their superficial sculpture, aflbrd a key to the subordinate grouping of these numerous species and indicates several important subsidiary lines of development. These species seem to have appeared as early as the Niagara fauna, in which occurs a suborbicular form ( S. pramonens, sp. nov.) with low fold and sinus, similar to S. Hungerfordi, Hall, of the upper Devonian. In the 24 PALEONTOLOGY OF NEW YORK. Lowei- Helderberg fauna we have but the single species, S. concinnus. Hall ; in the Oriskany sandstone, S. arenosus, Conrad ; in the Corniferous limestone, S. unicus, Hall (= S. arenosus), S. Grieri, Hall, and S. divaricatus, Hall. The last named species is the only representative of this type of structure in the Hamilton faunas, l)ut from the upper Devonian onward the species multiply rapidly, becoming most abundant and varied in the diflferent faunas of the lower Carboniferous and continuing until the close of palasozoic time. The key-note to the time value of the Apertukati was suggested by De V^erneuil, who divided them into two subsections, " the first including species with fine, not dichotomous plications, all of which belong to the Devonian system ; the second including those with broad [simple] plications or those which have the plica- tions fine and always dichotomous. Spirifers of the last division are all Carboniferous or Permian."* With some reservation this statement is emi- nently true of the American Aperturati, with which alone in the following classification we have to deal. (a) Disjunctus-type. Forms with well developed fold and sinus, elongate hinge and elevated cardinal area ; lateral plications simple, median plications dichotomous or intercalary. Spirifer arenosus, Conrad, Oriskany sandstone. Spirifer unicus. Hall, Corniferous limestone. Spirifer Whitneiji, Hall, Lower upper Devonian. Spirifer disjundus, Sowerby,! Chemung group. In the higher Chemung sandstone of Alleghany and Cattaraugus counties, N. Y., there is a well defined variety of this species which is of not uncommon occurrence. It is distinguished by a conspicuous median sulcus on the fold and has been well figured in Palaeontology of New York, Volume IV, pi. xli, figs. 10-16. We propose to distinguish it by the varietal term sulcifer. *Geolog-ie de la Russie de I'Europe, p. 126, 1845. t A prefereiK-e is frequently expressed by the Continental writers for the term S. Verneuili, applied to this species by Murchison in 1840. In regard to the priority of these name.s both introduced in the same year, Murchison has said in the 3d edition of his " Siluria" (p. 422, 1859) : " Von Dechen and his associates have used the name given by myself in honor of my friend De Vbrneuil to the Spirifer which abounds in the same stratum [Verneuili-shales] in the Boulonnais. It is, however, the Spirifer disjunctus, having beeu previously named by Sowehby." BRACHIOPODA. 25 A subordinate division of this section is the (1) Hungerfordi-type, in which the fold and sinus are low, often obso- lescent, the outline suborbicular and the cardinal area compressed laterally and incurved; dental lamellae prominently developed. This type is repre- sented by S. pramonens, sp. nov., Niagara group. S. Hungerfordi, Hall, Lower upper Devonian. To the same division belongs the Russian species, S. Anossofi, de Verneuil, which TscHERNYSCHEW Considers as probably identical with S. Hungerfordi and an important index fossil of his uppermost middle Devonian fauna on the west slope of the Urals.* Here must also be placed the Spirifer Mosquensis, Fischer, from the Carbonif- erous limestone of Miaschkowa, Russia, and the type of the genus Choristites, Fischer. Spirifer Grimesi, Hall, of the Burlington limestone resembles this Russian species in external form, but lacks the prominent development of the dental lamellae and the simple lateral plications possessed by S. Hungerfordi and S. Mosquensis. In our opinion, if the term Choristites is to be admitted with subgeneric significance, it should be restricted to this small group of species beginning in the upper Silurian and ending in the Carboniferous. (b) Striatus-type. Forms having a great number of duplicate lateral plica- tions, well developed, rarely acuminate fold and sinus, and narrow, usually extended cardinal area. Species following closely the type of S. striatus are not common in American faunas though they abound elsewhere. We have : S. striatiformis, Meek, Waverly sandstone. S. Logani, Hall, Keokuk group. S. striatus, Martin, Coal measures. S. Marcoui, Waagen, Coal measures. An important subsection of this group is composed of a series of forms representing successive stages in a line of development, which diverged early from the Striatus-stock and eventuated in some extravagant expressions of this type. * Die Fauna des mittlei-eii und obei-en Devon am West-Abhange des Urals, pp. 174, 175. 26 PALMONTOLOGY OF NEW YORK. In Spirifcr fastigatus. Meek and Worthen * of the Keokuk group, the fascic- ulation of the plications is very pronounced, the duplication of these plications beginning at an early stage in the development of the animal. In S. Missouri- ensis, Swallow, of the Choteau limestone, a similar fasciculation is apparent In S. cameratus, Morton, of the Coal measures, this character becomes very conspic- uous, while the extreme of development is attained in S. Texanus, Meek, where the plications are sharply fasciculate, while the hinge is short, the fold and sinus prominent and acute and the surface granulose. Spir if er fastigatus, S. cameratus and jS. Texanus might each well be taken as a type of structure of subordinate value to that of S. striaius, but in American faunas there are but these single I'epresentatives of each variation.! (c) Imbrex-type. Alate, mucronate shells, with narrow cardinal area, fine, simple ( very rarely duplicate ) lateral plications, the plications on fold and sinus being of about the same size as the rest. The surface is frequently lamellose. This group is restricted to the earlier faunas of the Carboniferous and is represented by S. Newberryi, Hall, Waverly group. H. Marionensis, Shumard, Waverly and Choteau groups. S. hiplicatus, Hall, Kinderhook group. S. imbrex, Hall, Burlington limestone. S. incertus. Hall, Burlington limestone. S. Forbesi, Hall, Burlington limestone. »S rosiellatus, Hall, Keokuk group. S. tenuicostatus. Hall, Keokuk group. »S'. subcequalis, Hall, Keokuk and St. Louis groups. S. lateralis. Hall, Keokuk and St. Louis groups. (d) Suborbicularis-type. Forms with suborbicular outline, broad, low and usually simple lateral plications ; the median plications are few and indistinct. S^. suborbicular is. Hall, Kinderhook-Keokuk groups. S. subcardiiformis. Hall, St. Louis group. * As this name was preoccupied by Morton, Mr. S. A. Miller has introduced in its place S. Mortonanus. t Waagen has inchided in his "Group of Spirifer teaulatun, Trautschold," 8. Miisakheylerms, Davidson, and (S. AmUensis, Waagen, all Carboniferous species of the Cameratus-type. BRACHIOPODA. 27 These species suggest the short-winged, rounded forms of . 128, 129, 132, 135, 154, 155, 156, ]58, 161, 163, 164. 1858. Delthyris, Rogers. Geol. Survey Pennsylvania, vol. ii, p. 828; figs. 669, 670. 1858. Spirifer, H k\.h. Geol. Survey Iowa, vol. i, pt. ii, p. 508. pi. iv, fig. 7; p. 509, jil. iv, fig. 8; p. 510, pi. v, tig. 1 ; p. 520, pi. vii, fig. 7. 1863. Spirifera, Billings. Geology of Canada, p. 386, tigs. 422a, b. 1867. Spirifn-a,Y{k-Lh. Palaeontology of N. Y., vol. iv, p. 197, pi. xxix, tigs. 1-8 ; p. 198, jil. xxiv, figs. 9-18; p. 209, pi. xxxi, figs 14-19; ji. 211, pi. xxxi, tigs. 11-13, 20-30; p. 220, pi. xxviii, figs. 12-16 ; p. 223, pi. xxxvi, figs. 1-13 ; p. 226, pi. xxxvii, tigs. 10-20; p. 227, pi xxxviii, figs. 1-25; pi. xxxviii*, figs. 12-18; p. 230, pi. xxxviii«, tigs. 23-32 ; p. 234, pi. xxxv, fig. 24 ; p. 292, pi. xxx, tigs. 16-20. I8GS. Spirifera, Meek and Worthen. Geol. Survey Illinois, vol. iii, p 433, ]il. xiii, fig. 8. 1868. Spirifer, Meek and Worthen. Geol. Survey Illinois, vol. iii, p. 414, plate x, fig. 1. 1878. Spirifera, Miller. Proc. Davenport Acad. Nat. Sci., p. 222. 1880. Spirifera, White. Second Ann. Rept. Bureau Stat, and Geol. Indiana, p. 503, pi. iv, figs. 1-3 ; ]). 504, pi. iv, figs. 4, 5 1881. Spirifera, White. Tenth Ann. Rept. State Geologist Indiana, p. 135, pi. iv, figs. 1-3 ; p. 136, pi. iv, figs. 4. 5. 1882. Spirifera (Oyrtina), VfuiTi'mhi). Geol. Wisconsin, vol. iv, p. 329, pi. xxv, figs. 25, 26 ; p. 329, pi. xxvi, fig. 3; p. 330, pi. xxvi, tig. 4 ; p. 331, pi. xxvi, figs. 1, 2. 1883. Spirifera, Calvin. American Journal of Science, vol. xxv, p. 433. 1884. Spirifera, Walcott. Pateontology of the Eureka District, p. 137, pi. xiv, tig. 10. 1885. Spirifera, Clarke. Bull. No. 16, U. S. Geol. Survey, p. 31, pi. iii, fig. 12. 1888. Spirifera, Calvin. Bull. Laboratories State University Iowa, p. 19. 1889. Sinrifffra, Nettelroth. Kentucky Fossil Shells, p. 105, pi. viii, figs. 1-8 ; p. 107, pi. ix, figs. 1-7 ; p. 11.5, 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. i'. Parryanus, Hall, 8. 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. Thei'e 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), S. audaculus, Conrad (= S. medialis, Hall), S. Marcyi, Hall, S. asper, Hall, S. Macbridii, Calvin, S. eurytines, Owen. The differences of exterior are quite subordinate ; the majority of the species, exemplified by /S. audaculus, have smooth or laraellose plications, which are often marked by a linear depression on the summit of each ; while others have the plications covered with elongate pustules (S. granulosus, S. Marcyi) or erect granules (S. asper). In S. Parryanus the minute elongate pustules are arranged upon the summits of distinct fine radial strias. A character which appears at times in other groups, but which here possesses the highest significance, is the gradual development of the callosity or trans- verse plate in the apex of the delthyrium. Originally, and always in the earlier species (S. perextensus. Meek and Worthen, S. macroihyris. Hall, etc.) an accompaniment of adult or senile growth, it eventually becomes a permanent character existing throughout all the later immature growth-phases of the 30 PALEONTOLOGY OF NEW YORK. shell. In its simpler inauifestatioiis it is a testaceous deposit extemliiig across the delthyriuin from its inner margins ; as its size increases it unites the dental lamellse, fills the rostral cavity of the valve and extends forward along the bottom of the shell between the posterior extremities of the diductor muscular bands. This is its condition as usually seen in the middle Devonian species, (S. granulosus and H. audaculus. Not infrequently this plate is less thickened and extends downward with a convex outer surface for two-thirds the length of the delthyrium, but this particular form of development occurs less often in the early species. In all its phases it may be coexistent with the true deltidium, though the latter is rarely retained in growth-stages where the apical callosity is well de- veloped. From the last mentioned condition to the fully developed, adherent split tube of Syringothyris,* it is but a few short steps, but these are still wanting among the American Spirifers, as flir as our observations have gone. An important intermediate stage is furnished by the peculiar species which we have provisionally placed in the so-called Cyrtia, namely, Spirifer alius, Hall, an extravagant representative of the European S. simplex. Here the transverse plate is thickened on its inner surface by the development of a vertical median ridge. In Syringothyris it is evident that the tube has been formed by the lateral expansion of this ridge, its margins becoming free and developing a tendency to incurve or curl toward each other over the median line, actually uniting at times while adherent to the plate, but remaining disconnected after the tube becomes free. It is very probable that the thin epidermal layer of the shell in the gran- ulous species of the Ostiolati was punctated ; indeed the tuberculated surface itself, may be construed as evidence of such slight punctation.f In Syringo- thyris the shell is decidedly but variably punctated, the tubules sometimes penetrating the entire thickness of the shell, sometimes traversing only a * For a more detailed account of the structure of this org-an see the discussion of the genus Sybingo- THYnis. t Mi-. John Yodng. of Glasgow, has shown that the epidermal shell layer is minutely punctate in Spirifo- Hneatus (see Davidson, Supplement, to Carboniferous Briichiopoda, p. 275, pi. xxxiv, fig. 9), and it ia not unlikely that the existence of a very tenuous external punctated layer will be found more generally prevalent among Spirifers than is now genei'ally supposed. BRACHIOPODA. 31 portion of the inner layers ; and on different portions of the valves the feature is differently developed. In Spirifer plenus, Hall, of the Burlington limestone, we have an example of a true Spirifer with the apical callosity in about the condition of development exhibited by the Devonian species, S granulosus; that is, with the syringothyroid tube incipient, but in which the shell is punctated for its entire thickness. Of the Ostiolati, or syringothyroid Spirifers, the American faunas possess a considerable representation. The type was not specialized until the opening of the Devonian, and with the exception of the species just cited, S. plenus, and 8. negledus, Hall, of the Keokuk group, it passt-d into Syringothvris at the close of the Devonian period. It is, therefore, a Devonian spiriferoid type of preeminent importance. A member of this group which represents a form of exterior somewhat un- like that of a'll the other species here associated with it, is Spirifer acuminntus, Conrad ; characterized by its broad duplicate lateral plications, a feature of the rarest occurrence among the Ostiolati. This specific type, however, is wide- spread, being represented in the Devonian faunas of the continent of Europe by the shell known as S. cuUrijugatus, F. Roemer.* In the Upper Helderberg limestone are the following species of Ostiolati : S. perextensus, Meek and Worthen. S. Manni, Hall. S. macrothyris, Hall. S. acuminatus, Conrad. S. angustus, Hall. In the Hamilton group : S. angustus. Hall. S. granulosus, Conrad. S. Marcyi, Hall. S.fornax, Hall. & acuminatus, Conrad. S. eurytines, Owen. S. audaculus, Conrad. S. Parryanus, Hall. S. ligus =pennatus, Owen. S. asper. Hall. S. Wortheni, Hall. S. Macbridii, Calvin. *See RoBMKR, Das rhein. Uebergangsgebii-ge, pi. Iv, fig. 4; Schuh., Beschr. Eifel. Brach., pi. xxxiii, tig. 1. Most instructive figures are given by QiiENSTEDT, Brac-hiopoilen, p!. lii, figs. 19-21. There is little doubt of tlie specific identity of the shells passing under these two names, and Roemer's designation must eventually give way to the earlier one of Conrad. 32 ■ PALEONTOLOGY OF NEW YORK. With the increase of the Aperturati, the OstioLati diminish rapidly and in the upper Devonian fiiunas we know but a single species, S. asper, from the Chemung group of New York.* VI. Glabrati. Typical examples, Spirifer glaber, Martin, Martiniopsis inflata, Waagen. Forms with the surface smooth and glabrous ; fold and sinus faintly devel- oped except at the anterior margins of the valves. The species embraced in this division have stronger differential characters than are found among the preceding groups. The shells have a very short hinge and low cardinal area, and the subcircular marginal outline causes a noticeable alteration in the form of the spiral arms. These have their bases well forward and are extended obliquely to the rounded cardinal extremities, in their position thus approximating the form assumed by these organs in Cyrtia and Cyrtina ; the crura, also, and the primary lamellae become very long. This difi'erence is not, however, one of great significance and is to be expected in any Spirifer having such an outline. The character of the muscular impressions is of greater importance ; the broad scars of the diductors in the pedicle-valve are here reduced to very narrow dimensions, are scarcely depressed and frequently not defined, but represented only by a radiate marking of the shell. In the brachial valve the adductor scars are two narrow impressions which widen anteriorly but are not divided ti-ansversely. The surface of the shell was covered with very fine concentric lines and the epidermal layer which is usually effaced, was minutely punctate. Faint lateral plications are sometimes visible. These differences from the normal type of Spirifer have led many writers to adopt McCoy's term Martinia for S. glaber and its allies. It is evident, however, that this division of the smooth-shelled species embraces more than one subordinate type of structure ; they may divided into 1. Aseptati (= Martinia, McCoy, 1844). Shells in which dental lamellae and septa are wanting. * There is a large ami hitherto uinlescrihed representative of this f,n-oiip in the limestone at Littleton, Iowa, which is regarded by Piofessor Calvin as of upper Devonian ag-e. BRACHIOPODA. 33 McCoy's first species of his genus was »S'. decorus, Phillips, which Davidson has regarded equivalent to Martin's earlier name Anomites glaber, a well known and widely distributed Carboniferous species. American representatives of this type of structure are of exceedingly rare occurrence. Dr. Davidson has identified S. glaber in the Carboniferous lime- stone of Nova Scotia,* and Meek and Worthen have described S. glaber, var. contractus, from the Chester limestone of Illinois. It has also been stated that the species S. glaber occurs in the Devonian, but it would seem that such identifications should be carefully reviewed. Davidson, in his description of the Carboniferous brachiopods (p. 62), mentioned the fact that he had certain forms from the English Devonian which he considered in- distinguishable from this Carboniferous species but he did not describe them at greater length, nor illustrate them. The shell called S. glaber by Kayser (Zeitschrift der deutsch. geolog. Gesellsch., Bnd. xxiii, p. 581, pi. xii, fig. 1, 187 1), from the middle Devonian of the Rhine, is evidently quite distinct from .this species. Mr. Walcott has described under the name S. {Martinia) glaber, var. Nevadensis, a shell from the Eureka District of Nevada, which is stated to possess a surface bearing " obscure radiating plications, concentric striee about 1 mm. distant [from each other], also fine radiating interrupted strite " (Monographs U. S. Geological Survey, viii, p. 139, 1884). Both the description and the illus- trations given of this fossil suggest the Devonian species »S'. euryglossus, Schnur, which, like H. curvatus, Schlotheim, is a fimbriate species belonging to the pauciplicate or .S'. /^m-group of the unicispinous section. Prof H. S. Williams (The Life-History of Spirifer lavis; Ann. N. Y. Acad. Sci., vol. ii. No. 6, pp. 16 et seq., 1881) has endeavored to demonstrate a lineal relationship between S. glaber and S. Icevis of the lower Portage group, the latter a fimbriate species, the former non-fimbriate. In Mr. Walcott's work, referred to, this idea is carried to its logical extreme, the author referring the fimbriate species, S. undiferus, F. Roemer, S. fimbriatus, Conrad, S. subundiferus, Meek and Worthen, etc., to tlie genus Martinia together with S. glaber (pp. 144-146), and taking no note of the highly important difference between the fimbriate Spirifers with simple and with compound spines. * Quarterly Journal Geological Society, 1863, p. 170. 34 PALEONTOLOGY OF NEW YORK. The Devonian form, S. Mala, Hall ( = Athyris Maia, Billings), from the Cor- niferous limestone, is an excellent representative of this type of structure both externally and internally ; and the list is completed, so far as our knowledge goes, by the addition of -S. subumbona, Hall, of the Hamilton group. 2. Septati. Shells in which dental plates or septa are well developed. We are compelled to recognize two groups of the septate Glabrati : (a) Martiniopsis, Waagen, 1883. Species with the lamellae developed in both valves. Waagen has described two species of this genus, M. inflata and M. subpentago- nalis, from the Productus limestone of India,* and suggests that this type of structure appeared in the Devonian. Beyond the account given by Dr. Waagen we know nothing of these fossils. (b) (" Gen. nov.," Tschernyschew), Type of Martinia semiplana, Waagen. Shells with dental lamellse scarcely developed, but with a prominent median septum in the pedicle-valve. Dr. Tschernyschew has called attention to the peculiar structure of this shell,f suggesting the desirability of separating it from its usual association by a distinct designation. The species was embraced in the genus Martinia by Waagen, who did not observe the presence of the internal septum. Waagen and Tschernyschew call attention to the generic similarity of Kutorga's Spirifer corculum with this species, both of which are from the Artinsk-beds, or Permo- carboniferous of Russia. It seems very doubtful if these forms should be separated from Quenstedt's genus Mentzelia J established upon the Spirifer medianus from the Muschelkalk of Silesia (Tarnowitz) ; though Dr. Tschernyschew finds the essential differ- ence in the presence of dental lamellae in the latter and their absence in the Carboniferous species. Quenstedt compares these characters in S. mediaiius to those of S. glaber, saying that they " bios an der Wand ankleben, und sich nur an der Spitze des Loches auf die zierliche dreieckige Querlamelle stiitzen." * Memoirs Geological Sui-vey of India ; Productus-limeslone Fossils, p. 524. t AUgemeine geologische Karte von Russland, Blatt 139 ; Beschreibung des Central-Urals und Westab- hanges, p. 369, pi. v, figs. 1, 3, 1889. I Petrefactenkunde Deutschlands ; Brachiopoden, p. 522, 1871. BRACHIOPODA. 35 The presence of the median septum establishes another line of connection with the post-palaeozoic members of the genus Spiriferina, while the punctation of the epidermal layer only, retains these fossils in close association with the glabrate Spirifers. The following table will afford a summary of the foregoing classification as far as it relates to the North American Spirifers. The names of species of which specimens have been examined stand in Roman text ; those which have been placed in the grouping from a study of descriptions and illustrations only, are in italics ; others, in regard to whose relations it has seemed unwise to ex- press an opinion on account of the insufficiency of our knowledge, are omitted. Any names of extra-liinital species stand in brackets. I. Radiati : 1 . Pauciplicati : S. radiatus, Sowerby, S. Eudora, Hall, S. Meta, Hall, S. Foggi, Nettelroth, S. rostellum. Hall and Whitfield, S. macropleura, Conrad, 2. Multiplicati : S. Niagarensis, Conrad, S. asperatus, Ringueberg, S. Tullius, Hall, S. Belphegor, Clarke, S. mesastrialis. Hall, S. sp. indes., 3. Dupliciplicati : S. nobilis, Barrande, [S. Schmidti, Lindstrum, II. Lamellosi: 1. Septati: S. sulcatus, Hisinger, S. perlamellosus. Hall, Clinton and Niagara groups. Niagara group. Niagara group. Niagara group. Niagara group. Lower Helderberg group. Niagara group. Niagara group. Hamilton group. Genesee shale. Chemung group. Lower Carboniferous. Niagara group. Wenlock limestone.] Niagara group. Lower Helderberg group. 36 PALAEONTOLOGY OF NEW YORK. S. raricostus, Conrad, (?) S. Knappianus, Nettelroth, (?) S. disparilis, Hall, S. zic-zac. Hall = S. consobrinus, D'Orbigny, S. mesacostalis, Hall, 2. Aseptati : a. Mucronatus-type : S. segmentus. Hall, S. arctisegnientus, Hall, S. mucronatus, Conrad, (S. bidorsalis, Winchell, S. sculptilis, Hall, S. Hobbsi, Nettelroth, S. Byrnesi, Nettelroth, S. varicosus, Hall, S. subattenuatus, Hall, S. bimesialis, Hall, S. desideratus, Walcott, h. Submucronatus-tjpe : S. Engelmanni, Meek and Worthen= S. Worthenanus, Schuchert, S. submucronatus, Hall, S. CumberlanditB, Hall, S. macrus, Hall, S. Davisi, Nettelroth, (?) S. gregarius, Clapp, Upper Helderberg group. Upper Helderberg group. Upper Helderberg group. Hamilton group. Chemung group. Upper Helderberg group. Upper Helderberg group. Hamilton group. Hamilton group. Hamilton group. Hamilton group. Hamilton group. Hamilton group. Hamilton and Chemung groups. Hamilton and Chemung groups. Lower Carboniferous. Oriskany sandstone. Oriskany sandstone. Oriskany sandstone. Corniferous limestone. Corniferous limestone. Corniferous limestone. III. FlMBRIATi: 1. Unicispinei =Delthyris, Dalman, 1828 a. Crispus-type : S. crispus, Hisinger, S. crispus, var. simplex. Hall, S. Vanuxemi, Hall, S. Saffordi, Hall, S. cyclopterus, Hall, Niagara group. Niagara group. Lower Helderberg group. Lower Helderberg group. Lower Helderberg group. BRACHIOPODA. 37 S. octocostatus, Hall, Lower Helderberg group. S. arrectus, Hall, Oriskany sandstone. S..tribulis, Hall, Oriskany sandstone. S. hemicydus. Meek and Worthen, Oriskany sandstone. S. duodenarius, Hall, b. Laevis-type. S. bicostatus, Vanuxem, S. bicostatus, var. petilus, Hall, S. modestus. Hall, (?) S. nyvipha, Billings, S. Canandaiguse, sp. nov., (?) S. urbanus, Calvin, S. Isevis, Hall, Duplicispinei ^Reticularia, McCoy, 1844: S. fimbriatus, Conrad, Oriskany, Corniferous and Hamil- ton groups. S. subundiferus. Meek and Worthen, Hamilton Group. Corniferous limestone. Niagara group. Niagara group. Lower Helderberg group. Lower Helderberg group. Hamilton group. Hamilton group. Portage group. IV. (?) S. praematurus, Hall, S. hirtus, White and Whitfield, S. pseudolineatus. Hall, S; setigerus. Hall, S. clarus, Swallow, S. lineatus, Martin, S. perplexus, McChesney, Aperturati : a. Disjunctus-type : S. arenosus, Hall, S. unicus. Hall, S. Whitneyi, Hall, S. disjunctus, Sowerby, Chemung group. Choteau limestone. Kinderhook-Keokuk groups. St. Louis-Chester groups. Chester limestone. Coal Measures. Coal Measures. Oriskany sandstone. Corniferous limestone. Upper Devonian. Chemung grouj). S. disjunctus, var sulcifer, var. nov. Chemung group. S. BilUngsanus, Miller, Devonian. L Hungerfordi-type. = Choristites, Fisher, 1825: S. prsemonens, sp. nov., Niagara group. S. Hungerfordi, Hall, Upper Devonian. 38 PALEONTOLOGY OF NEW YORK. b. Striatus-type : S. striatiformis, Meek, S. Grimesi, Hall, S. Logani, Hall, S. striatus, Martin, *S. Marcoui, Waagen, 1. Texan US-line: S. Missouriensis, Swallow, S. tenuimarginatus. Hall, S. Mortonanus, Miller, S. cameratus, Morton, S. Texanus, Meek, c. Imbrex-type : S. Newberryi, Hall, S. centronatus, Winchell, S. Marionensis, Shumard, /S. albapimnsis. Hall and Whitfield, S. biplicatus, Hall and Whitfield, S. imbrex, Hall, S. Forbesi, Hall, S. incertus, Hall, S. tenuicostatus. Hall, S. lateralis. Hall, S. subsequalis, Hall, d. Suborbicularis-type : S. subrotundatus, Hall, S. suborbicularis. Hall, S. subcardiiformis, Hall, e. Orestes-type : S. concinnus. Hall, S. Grieri, Hall, S. Orestes, Hall and Whitfield, S. Williamsi, sp. nov., S. Keokuk, Hall, S. Littoni, Hall, S. bifurcatus, Hall, Waverly group. Burlington limestone. Burlington limestone. Coal Measures. Coal Measures. Choteau group. Keokuk group. Keokuk group. Coal Measures. Coal Measures. Waverly group. Waverly group. Choteau and Waverly groups. Kinderhook group. Kinderhook group. Burlington limestone. Burlington limestone. Burlington limestone. Keokuk group. Warsaw limestone. Warsaw limestone. Kinderhook group. Keokuk group. Warsaw limestone. Lower Helderberg group. Upper Helderberg group. Upper Devonian. Chemung group. Keokuk group. St. Louis group. St. Louis group. BRACHIOPODA. 39 S. Leidyi, Norwood and Pratten, St. Louis group. S. Leidyi, var. Meramecensis, Swallow, Warsaw Ihnestoue. /S Leidyi,\9x. Chesterensis, Swallow, Chester limestone. S. increbescens, Hall, S. increbescens, var. Americanus, Swallow, S. increbescens, var. transversalis. Hall, S. opimus. Hall, t. of Tennessee, pp. 17, 48. 1841. Cyrtia, Troost. Sixth Geol. Rept. of Tennessee, pp. 11. 12. 1847. Spirife); Yandell and Shum.ard. Contribution to the Geology of Kentucky, pp. 19, 21. 1855. Cyrtia, McCoy. British Palaeozoic Fossils, p. 426. 1857. Spirifer, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., pp. 169, 170. 1858. Spirifer, Hall. GeoIOfry of Iowa, vol. i, part ii, pp. 520, 603, 646, 647, pi. vii, fig. 6 ; pi. xiii, fig. 4 ; pi. XX, fig. 5. 1860. Spirifer (Cyrtial), Swallow. Trans. St. Louis Acail. Sci., vol. i, ji. 647. 1863. Syringothyris, A. Winchell. Proc. Acad. Nat. Sci. Philadeliihia, vol. vii, sec. ser., pp. 6-S. 1865. Syringothyris, Meek. Pi-oc. Acad. Nat. Sci. Philadelphia, vol. ix, sec. ser., p. 275. 1866. Spirifera, Hall. Proc. American Philosophical Society, vol. x, p. 241. 1867. Spirifer, Meek. American Journal Science, vol. xliii, p. 407. 1868. Spirifer, Meek and Wouthen. Geol. Survey of Illinois, vol. iii, p. h'iO. \A. xix, fig. 8. 1870. Syrlngothyris, A. Winchell. Proc. American Philo.sophical Society, vol. xii, p. 252. 1875. Syringothyris, Meek. Palreontology of Ohio, vol. ii, pp. 285, 288, pi. xiv, fig. 7. 1875. Syringothyris, White. Wheeler's Geogr. Surveys West of the lOOIh Meridian, vol. iv, jiji. 88, 90, pi. V, tig. 9. 1877. Spirifer, Meek. King's U. S. Geol. Kxpl. of the 40th Parallel, vol. iv, p. 87, pi. iii. fig. 11. 1880. Spirifer, White. Second Annual Rept. Indiana Bureau of Statistics and Geology, |>. 512, pi. vii, figs. 1, 2. 1881. Spii-ifer, White. Tenth Rejit. State Geol. of Indiana, p. 144, \i\. vii, figs. 1, 2. 1884. Syringothyris, Walcoti'. Monogr. U. S. Geol. Survey, vol. viii, p. 219. 1888. Syringothyris, Herrick. Bulletin Denison University, vol. iii, p. 41, pi, i, fig. 7; jil. 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, tig. 6. 1890. Syringothyris. Schdchert. 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 PALEONTOLOGY 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 brachial 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. y^ l). The shell structure is more or less distinctly and abundantly punctate. It is probable that these punctge perforate the epidermal layer and extend to the inner laminae of the shell. The exterior is usually ^'" ^^ '^''^ pnmaiy lameiLo^ of •^ Syringothyris typa- covered with a finely textile ornament which has been compared, in appearance, to " twilled cloth." Type, Syringothyris 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 Spirifer {S. plenus, Hall) in which the trans- verse plate and split tube of Syringothyris are not present, aiid 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. King, in 1868,* claimed to have found traces of this tube or canaliferous plate in a rudimentary condition in several species of Spirifer, e. g., S. striatus, * Annals and Magazine of Natural Histoiy, Fourth series, 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 beneath 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. cmpidatus 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 also be referred to Dr. Carpenter's earlier observations in his report to the British Association, 1844, " On the Microscojiic Structure of Shells," and to his treatise in Davidson's Introduction, " On the Intimate Structure of the Shells of the Brachiopoda," 1852. t Proc. Academy of Ntitural Sciences, Phila., vol. ix, second ser., p. 275. 1865. 50 PALEONTOLOGY OF NEW YORK. the shell than in others, a variation wliich may be due to the easy destruction of the delicate pores which are exceedingly small and much .finer than in Spiriferina, 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 Syringothyris 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 Syringothyris 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 Herriok, but Schuchert 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 textus. Hall, S. subcuspi- datus, Hall, S. propinquus, Hall). *This is evidently an undescribed shell, ami as it is an important one for our purposes the name /Syringotliyris Missottri is proposed. Its highly punctate shell, its size and form, all indicate a deviation toward Cyrtina, while the canalifoi-ra transverse plate is developed as a vei-y delicate structui'e. For a fuller description of the species see the supplement to this volume. t On Syringothyris, Winchell, and its American species ; Report of the N. Y. State Geologist for 1889, p. 230. 1890. I Proc. American Philosophical Society, vol, xvi, 1889, p. 435. These wei-e described as jS'. Randalli and var anguUtta, \mi as the former possesses a plicate fold and sinus and in the lattei- the fold and sinus are smooth, it will be better to i-egard them as distinct species. BRACHIOPODA. 51 Mr. ScHUCHERT has also referred to Syringothyris the species Spirifer extenua- tus, Hall, of the Kinderhook group, for which he regards the Sijringothijris Halli, Winchell, a synonym ; and to the same genus, the Cyrtia gigas, Troost, from the lower Carboniferous of Tennessee, though we are without conclusive evidence of the nature of the interior in this fossil. Genus SPIRIFERINA, u'Crbigny. 1847. PLATES XXXV, XXXVI, XXXIX. 1847. Spinferina, d'Ohbigny. Comptes rendiis, vol. xxv, ji. 268. 1850. /Spiriferina, d'Orbigny. Annales des Sciences Natiii-elles, vol. xiii, ji. 334. 1852. Sjnrifer, Hall. .Slaiisbui'y's Expl. and Survey of the Valley of the Great Salt Lake of Utah, p. 409, pi. iv, tig. 4. 1S54. Spiriferina, Davidson. Bi-itish Fos.sil Brachiopoda, p. 82, pi. vi, tig-. 60. 1855. Spirifer, Shdmard. Geology of Missouri, vol. i, p. 203. 1856. Spirifer, Norwood and Prattbn. Journal Acad. Nat. Sci., Philadelphia, vol. iii, p. 71, ]il. ix, fig. 1. 1856. Spirifer, Hall. Pacific Raili-oail Reports, vol. iii, p. 102, pi. ii, figs. ]0, 11. 1858. Spiriferina, Shumard. Ti-ans. St. Louis Acad. Sci., vol. i, pp. 294, 391. 1858. Spirifer, Hall. Transactions of the Albany Institute, vol. iv, p. 7. 1858. Spirifer, Hall. Geology of Iowa, vol. i, part ii, p. 706, pi. xxvii, fig. 5. 1859. Spirifer, Meek and Hayden. Proc. Acad. Nat. Sci., Philadelphia, vol. iii, sec. ser., p. 27. 1860. Spirifera, Mekk. Proc. Acad. Nat. Sci., Philadelphia, vol. iv, sec. ser., p. 310. I860. Spirifera, White. Journal Boston Society Nat. Hist., vol. vii, p. 232. 1860. Spirifera, McChesney. New Palaeozoic Fossils, pp. 42, 43. 1862. Spiriferina, White. Proc. Boston Society Nat. Hist., vol. ix, pp. 24, 25. 1863. Spiriferina, Davidson. Quart. Journal Geol. Society London, vol. xix, p. 170, jil. ix, fig. 6. 1S64. Spiriferitm, Meek. Palaeontology Upper Missoui-i, p. 19. 1865. Spiriferina, A. Winchell. Pi-oc. Acad. Nat. Sci , Philadelphia, vol. ix, sec. ser., pp. 119, 120. 1866. Spirifer, Swallow. Trans. St. Louis Acad. Sci., vol. ii, p. 489. 1866. Spirifer, Geinitz. C;irbon und Dyas in Nebraska, p. 45, pi. iii, fig. 19. 186S. Spirifera, McChesney. Ti-ans. Chicago Acad. Sci., vol. i, p. 34, pi. vi, fig. 3. 1872. Spiriferina. Meek. Hayden's U. S. Geol. Survey of Nebraska, p. 185, pi. vi, tig. 3 ; pi. viii, fig. 11. 1874. Spiriferina, Derby*. Bull. Cornell University, vol. i, p. 23, pi. ii, figs. 4-G, 13 ; pi. iii, figs. 12-14, 17; pi. V, fig. 4 ; pi. vi, figs. 8, 13, 14. 1875. Spiriferiiia, White. Wheeler's Geogr. Surveys West of the 100th Meridian, vol. iv, pp. 138, 139, pi. X, figs. 4, 8. 1876. Spirifera, Meek. Simpson's Rept. Expl. Gieat Basin of the Terr, of Utah, p. 352, pi. ii, fig. 1. 1877. Spiriferina, Meek. King's U. S. Geol. Expl. 40th Parallel, vol. iv, pp. 84, 85, pi. viii, fig. 1,5; pi. xii, fig. 12. 1877. Spirifei-a (Spiriferiiia ?), Hall and Whitfield. King's U. S. Geol. Expl. 40th Parallel, vol. iv, p. 281, pi. vi, fig. 17. 1878. Spiriferina, Dawson. Acadian Geology, third ed., p. 291, tig. 90. 1878. Spiriferina, Etheridge. Quart. Journal Geol. Society London, vol. xxxiv, p. 269. 1882. Spiriferina, Whitfield. Bull. American Mus. Nat. Hist., vol. i, p. 48, pi. vi, tigs. 1^', 17. 1883. Spirifei-ina. Hall. Twelfth Rept. State Geol. Indiana, p. 327, pi. xxix, figs. 16, 17. 52 PALEONTOLOGY OF NEW YORK. 1883. Spirifera (S-pirlftrina), Hall. Second Ann. Rfjit. State Upologist of N. Y., pi. Ix, (ig.s. 19-32, 26-29 ; jil. Ixi, tigs. 14-16. 18S4. tSpiriferina, White. Thirteenth Rept, State Geologist Indiana, p. 135, pi. xxxv, figs. 13, 14. 1884. Spiriferina, Walcott. Monogiaph U. S. Geological Survey, vol. viii, pp. 218, 219, pi. xviii, figs. 12, 13. 1888. Spinferina, Herrice. Bull. Denison University, vol. iii, p. 47, pi. ii, figs. 9-11 ; pi. v, fig. 13; pi. x, fig. 3. 1891. Spiriferina, Hbrrick. Bull. Geol. Soc, America, vol. ii, p. 46, pi. i, tig. 19. Shells resembling Spirifer in external aspect; interiorly the pedicle-valve bears a median septum resting upon the bottom of the valve, its posterior portion lying between, but not united with the strong dental lamellae. The pro- cesses on the primary lamellae are continuous, forming a simple transverse or subacute loop, p,,, 4, (-,,,, I , . 1 A i. ii 1 i_ Tiie \oo\} of Spiriferina Ken- bhell substance strongly punctate throughout. tucuensis, suumara. (o Type, Terebratulites rostralus, 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 ditferences. 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 lamellse, and the loop is a transverse band with a slight upward curve. Recent writers on the Triassic brachiopods, 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 so 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 fiices. 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. Spiriferina Walcotti, ^osvathy; showingmus- ment, but there is no reason for doubting its cuiarscarsouwaiis of median septum of " pedicle-valve, (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 Syrinqothyris 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. shell, Spiriferina cristata, Schlotheim, 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- lam ellose shell, but the specimens we have examined do not evince punctation. Spiriferina spinosa, Norwood and Pratten, and iS. 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. hinacuta and S. Clarksvillensis, Winchell, and S. suhtexta, 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 XXXrx. 1842. Ortlds, Conrad. Journal Acad. Nat. Sci. Philadelphia, vol. viii, p. 264. 1843. OHMs, Hall. Geology of N. Y. ; Kept. Fourth Dist., p. 180, fig. 8 ; p. 267, fig. 5. 1846. Orthis, Rouaclt. Bull. Soc. Geul. de France, sec. sev., vol. iv, p. 322, pi. iii, tig. 8. 1857. OHMs, Hall. Tenth Kept. N. Y. State Cab. Nat. Hist., p. 167, figs. 1-3. 1860. Amboccelia.llAhh. Thirteenth Rept. N.Y. State Cab. Nat. Hist., p. 71, figs. l-3;p. 72, figs. 4-6; p. 81. 1862. Ambocmlia (Spirifer f). White. Proc. Boston Soc. Nat. Hist., vol. ix, p. 26. 1864. Amboccelia, Meek and Hattden. Palaeontology of the Upper Missouri, p. 20, 1867. Amhoccelia, Hall. Pala;ontology of N. Y., vol. iv, pp. 258-262, pi. xliv, figs. 1-25. 1883. Amhoccelia, Claypole. Proc American Philosophical Society, vol. xxi, p. 232. 1887. Amboccelia, (Ehlbrt. Bull, de la Soc. d'Etudes Scientif. d'Angers, p. 6, pi. v. figs. 11-16. 1889. Amboccelia, Nettelhoth. Kentucky Fossil Shells, pp. 85, 86, pi. xvii, fige. 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 Paleontology 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 CEhlert,! 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 chai-acters of the Devonian forms of Amboccelia 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 In-achial valve, that the generic value of the group is beyond question. The type of structure is essentially * Chilidlum, Beecher. t Bulletin de la Societe d'Etiides Scienlitiques d'Angeis, 1887 s Brachiopodes du Devonien de I'Oueat de (a France, p. 6, pi. v, fig. 12. 56 PALjEONTOLOGY OF NEW YORK. Devonian. In America, Ambocalia uvibonata appears in the Corniferous lime- stone, and its existence is continued under more favorable conditions for devel- opment in the 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. umhnnata var. gregaria, Hall, is a very abundant shell. The Orthis umbonata was identified in the Devonian of western France (Gahard) by M.ARiE RouAULT as early as 1851,* and has been redescribed and figured by CEhlert 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 Amboccelia in the Coal Measures, where it is i-epresented 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- datns, 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. * Bull. Soc. G6ol. fie France, 2nd ser., t. viii, p. 322. t Palaeontology 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 sliort 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 tlie 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 having shown evidence of brachial supports. In some respects the characters 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 cheiroptijx, described by d'Archiac and de Verneuil,* from the middle Devonian at Paflfrath, and its ally in the Carboniferous limestones of Vis.-, N Oceani, d'Orbigny,t have *0n the Fossils of the Older Deposits of the Rhenish Provinces: Trans. Geol. Soc. London, vol. vi, p. 370, pi. XXXV, figs. 6, a, b, 1842. t Prodrome de Pal^ontologie stratigrapbique, pi. i, p. 149, 1850. See, also, Db Koninck, Faune du Cal- caire earbonifSre de la Belgique, 6e 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. Each valve is divided externally by two strong divergent ridges, into three depressed areas, one central and two lateral. Quensteut, considering both species identical, erected for their reception* a special sub- division of his Aperturati, viz., Cinda. 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, l)ut 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 XLVni. 1828. Terebmtula, Dalman. Kong. Vetenskaps-Akad. Handlingar. pi. vi, fig. 7. 1842. Atrijpa, Vanuxem. Geology of N. Y. ; Kept. Third Dist., p. 112, fi^. 5. 1843. Atrypa, Hall. Geology of N. Y. ; Kept. Fourth Dist., p. 71, fig. 3; p. 142, fig. 5 ; Tables of Oi'ganic Remains, No. 13, fig. 5. 18.'52. Atrypa, Hall. Palaeontology 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 ; p\. Ixxiv, fig. 10. 18.56. Ati-ypa, Billings. Canadian Naturalist and Geologist, vol. i, p. 137, pi. ii, fig. 9. 1858. Atrypa, Roger.s. Geology of Pennsylvania, vol. ii, part ii, p. 823, fig.''634. 1859. Merista, Hall. Palaeontology of N. Y., vol. iii, p. 253. 1859. Merista. Hall. Twelfth Kept. N. Y. State Cab. Nat. Hist., pp. 77, 78. 1862. Athyrls, Charhmellai, Billings. Palaeozoic Fossils, vol. i, p. 146, fig. 124; p. 166, fig. 150. 1863. Athyri.1. Billings. Geology of Canada, p. 317, figs. 320, 332-334. 1863. MeristoUa, Hall. Transactions of the Albany Institute, vol. iv, p. 226. 1867. Meristina, Hall. Palaeontology of N. Y., vol. iv, p. 299. 1867. Meristella, Davidson. British Silurian Brachiopoda, p. 112, pi. xxi, figs. 1-10. 1868. Athyris?, McChesney. Ti-ans. Chicago Acad. Science, vol. i, p. 33, pi. viii, fig. 2. 1873. Meristella {? Meristina), Meek. Palaeontology of Ohio, vol. i, p. 180, pi. xv, fig. 2. 1873. Athyrls. Nicholson and Hinde. Canadian Journal, vol. xiv, new ser., pp. 144, 157. 1875. Athyris, Nicholson. Palaeontology of the Province of Ontario, p. 61, fig. 32a ; p. 62, fig. 32e. 1879. Meristina, Hall. Twenty-eighth Kept. N. Y. State Mus. Nat. Hist., p. 160, pi. xxv, figs. 1-7. 1882. Mei-istina, Davidson. British Silurian Bi-achiopoda, Supplement, p. 94, pi. iv, figs. 20-23. Me)'istina, Hall. Eleventh Rept. State Geologist of Indiana, pp. 300, 301 ; pi. xxv, figs. 1-7. 1882. * Petrefactenkunde Deutschlands; Brachiopoden, p. 510, 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. Merisi'ma, Nettblkoth. Kentucky Fossil Shells, p. 102, pi. xxxiii, iigst. U), II. 1889. Meristina, Beecher and Clarke. Memoire N. Y. State Mus., ]>p. 67-70, p]. vii, figs. 4-13. Di.iGNosis. 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 deltidi.al 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. FIG. 43. Fig. 44. The loop of Whiifieldella nitida. Hall, (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 impres.sions, which are very fiiint, 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 bracMcUum may be applied to the calcified brachial supports of all Brachiopoda. 60 PALEONTOLOGY OF NEW YORK. Observations. This name is proposed as a substitute for the term Meristina 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 diflfer- 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 * Silurian 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- subtriangular in outline and subtruncate on the anterior margin. At the same time a larger foi'm with a more gi'adual anterior slope was designated as var. oblata. It is the latter which agrees more closely with the very abundant shell in the Niagai-a fauna of Waldron, Indiana, subsequently identified as Meristella nitida (Twenty-eighth Annual Report of the New York State Museum, p. ItiO. 1879), while the typical form of the species is found in the extension of the Niagara fauna to the southward, in the vicinity of Louisville, Kentucky. The similarity of the Waldron variation to the Meristina didyma, as identified by Davidson from the English Sihu-ian, is very close, while the typical Atrypa nitida seems to maintain per- manent differences. The Gotland forms of Atrypa didyma have a higher umbo than any of the American shells, constantly exposing the deltidial plates and the entire length of the pedicle-opening. BRACHIOPODA. 61 fauna of Square Lake, Maine. Of the foregoing species we know the character of the loop in Whitjiddella 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 Alrypn prunum, from an equivalent horizon in Gotland Genus HYATTELLA, gen. nov. PLATE XLVni. This term 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 po.ssess a loop like that of Whitfieldella, but presents some significant points of variation from tliat genus in other re- spects, viz. : "^ Fig. 45. The loop of Byattella The form is compactly subpentahedral ; the umbo cmgesta.iuM. {<■.) 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 surfoce of the shell and the ante-lateral margins are strikingly sinuate. Fine, sharp, closely crowded concentric strioe cover the exterior. The interior of the pedicle-valve has a deep and strongly striate pedicle-cavity, Ijounded by strong dental lamelte ; 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 elevated, 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 diflferences from other meristelloids are sufficient to justify the separa- tion of this species, with 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* Genus DAYIA, Davidson. 1881. PLATE LV. 1S39. Te)-ebi-atida, J. de C. Sowerby. Murchison's Silurian System, jil. v, Hg. 1. 1846. Atri/pa, McCoy. Synopsis Silurian Fossils of Ireland, p. 40. 1847. Terebratula, Barrande. Silnr. Brachiopoden aus Bohmen, pi. xv, fig. 4. 1848. Terebratula, Davidson. Bull. Soc. Geol. de ['""ranee, sec. ser., vol. v, pi. 328. 184S. Hypothyris, Phillips. Mem. Geol. Survey Great Britain, p. 281. 1852. HemiHiijris, McCoy. British Palajo/.oic Fossils, p. 204. 1859. RhynchcmeUa, Salter. Murchison'a Siluria, second ed., p. 545, pi. xxii, tig. 12. 1860. Rhynchonella, Lindstrom. Gotlands Brachiopoder, p. 381. 1869. Rhynchonella f, Davidson. British Silurian Brachiopoda, p. 190, pi. xxii, tigs. 20-23. 1881. Bayia, Davidson. Geological Magazine, new ser., vol. viii, p. 291. 1882. Bayia, Davidson. Britisli Silurian Brachiopoda, Supplement, 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, f 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 lamellas. In the bottom of the valve are two * Catalogues Silurian Fossils of Anlicoati, p. 46. 1866. t British Silurian Brachiopoda, p. 190, pi. xxii, tigs. 20-23. I 1881 and 1882, as cited. BRACHIOPODA. 63 narrow, divergent muscular grooves, bordered on their anterior edges by thick- ened ridges, both having the shape of a broad inverted V. In the brachial valve the character of the hinge-plate has not been ascer- tained, but was probably simple, and it was supported by a median septum traversing about one-half the length of the valve; on either side of this septum are the latei*al members of the adductor impression. The crura are short and straight ; the primary lamellae are attached to them by a subrectangular curve and pass outward just within the margin of the valve. The spirals are but slightly elevated and have their apices directed outward toward the lateral slopes of the opposite valve. The ribbon makes but three or four turns, and its outer anterior edges are quite coarsely fimbriated. Tlie loop is situated anteriorly, taking its origin near the upward turn of the primary lamellae ; it is directed upward and backward, the lateral processes meeting at or just behind the center of the interior cavity. From the point of union proceeds a short, simple process, which does not make an angle with the rest of the loop. We have had the opportunity of verifying most of these characters by cuttings of specimens obtaineil from the Gotland limestone. No congeneric species was known to Mr. Davidson, and, as far as our knowledge goes, there is no representative of this structure in the American palajozoic faunas. The external resemblance of Dayia navicula to the Atrypa bisuicata of the Trenton limestone, is worthy of remark, and the differences between the two in the structure of the brachidium are actually slight, though in one the spirals are everted and in the other they are inverted. Further notice is taken of these differences in the discussion of the genus Cyclgspira. Genus H IN DEL LA, Davidson. 1882. PLATE XLI. 1862. Athyrls, Billings. PaliBozoio Fossils, vol. i, p. 144, fig-. 121 ; p. H.'), tiff. 122. 1863. Athyris, Billings. Geology of Canada, p. 317, fig. 331. 1882. Hindella, Davidson. British Silurian Brachiopoda, Supplement, p. 130. 1885. Meristella, Foerste. Bull. Denison University, vol. i, p. 88, pi. xiii, tig. 2. Mr. Davidson has found that the meristelloid species described by Billings, from Junction Cliff, Anticosti (Division 1 of the Anticosti group), as Athyris 04 PALEONTOLOGY OF NEW YORK. umhonuia, possesses a peculiar loop connecting the spirals, and has, therefore, upon this character based a distinct genus. The situation of this organ, the Fio. 46. Fig. 47. The primary lamellie and loop of Hindella umbondta, Billings, (c.) loop, is very far forward, and its inclination to the primary lamellae is extremely oblique, the lateral processes or branches being directed backward in a low up- ward curve, uniting to form a short, straight, undivided stem. The posterior extremity of the entire process rarely extends back of the middle of the first lamellae and does not rise to the center of the bases of the spirals. The form of this loop is somewhat similar to that occurring in the genera, Whitfieldella, Hyattella, Nucleospira, etc., but its anterior position on the primary lamellae and its very depressed form are without parallel among these brachiopods with everted spirals. Congeneric with Hindella umbonata is Billings' Athyris Prinstana, from the same locality ; a shorter and more rotund form than H. umbonala, but probably no more than a variation of that species. Q ISS Fig. 48. Fig. 49. FiG. 60. Fig. 51. Consecutive transverse sections of tlie umbonal region of Hindella umbonata, Billings. Fig. 48. Section just below apex of peiliole-valve, showing the grooved pedicle-passage. Fig. 49. Section at ape.x of brachial valve, showing the dental lamellae. Fig. 60. A deeper section, e-thibiting the teeth, and the remnants of the dental lamella; bounding the muscular area. Fig. 61. Section showing the lateral elements of the hinge-plate. (c.) Some additional characters of these shells may be added : The outline is subcircular or elongate-ovate ; the valves convex ; the pedicle- valve being gibbous in the umbonal region. The hinge-line is very short but the cardinal slopes are frequently long and transverse, which, with the fulness of BRACHIOPODA. 65 the beaks of both valves, produces a " shouldered " appearance. There is a low- sinus on the pedicle-valve which is apparent only over the pallial region ; this is accompanied by a sliglit fold on the opposite valve. The apex of the pedicle- valve is closely incurved, concealing both deltidiuni and foramen. On the interior the teeth are moderately prominent and are supported by strong dental plates, which not only extend to the bottom of the valve, but are continued forward for about one-third the length of the shell, and inclose a narrow, elongate muscular area.* In the brachial valve the hinge-plate appears to be short and constructed on the same plan as that of Meristina and Whitfield- ELLA, with two diverging crural bases divided by a median groove, or a sub- triangular pit, and is supported by a median septum extending for about one- half the length of the valve. The spirals have their apices directed laterally and consist of nine or ten volutions of the ribbon. External surface smooth. Shell-structure fibrous, impunctate. The external expression of the shells of Hindella is rendered peculiar by the fulness and close incurvation of the beaks, and these are distinguishing features. While the character of the loop is unique, the deep muscular scar of the pedicle-valve, the structure of the hinge-plate, and the smooth external surface, are features which demonstrate the close relationship of the genus to Meristina and Whitfieldella. Genus MERISTINA, Hall. 1867. PLATE XLVII. 1828. Atrypa, Dalman. Kongl. Veteiiskaps Akail. Handling-., p. 134, pL v, fig. 3. 1860. Athyris, Roemer. Die Silurische Fauna der westlichen Tennessee, p. 70, pL v, fig. 12. 18fi3. MeriMella, Hall. Transactions of the Albany Institute, vol. iv, ]>. 212. 1866. Meristella, Davidson. British Silui-ian Braohiopoda, p. 109, pi. xi, figs. 1-13. 1867. MtT'isUna, Hall. Twentieth Rept. N. Y. State Cab. Nat. Hist., p. 157. 1867. Meristina, Hall. Palaeontology of N. Y., vol. iv, p. 299. 1872. Meristella, Hall and Whitfield. Twenty-fourth Rept. N. Y. State Cab. Nat. Hi.'it., p. 196. 1875. Meyistina, Hall and Whitfield. Palseontology of Ohio, vol. ii, p. 132, pi. vii, figs. 5, 6. 1878. Meristella, Etheridge. Quarterly Journal Geological Society London, p. 597. * All the internal characters of the valves here described have been derived fi-om transveree sections of the fhell. The material examined, most of which lias been placed at our service by the kindness of its col- lector, Pi-ol'e.=sor Alpheus Hyatt, has aftbided no interiors or single v.alves. The figures given above, of sections across the umboiial region, show some of the features mentioned. 66 PALAEONTOLOGY OF NEW YORK. . 1879. Meristim, Hall. Twenty-eighth Reiit. N. Y. State Miis. Nat. Hist., p. 159, pi. xxv, fig-s. 8-12. 1881. Whitfieldia, David.son. Geological Magaziiie, new ser., vol. viii, p. l.'J6. 1882. Meristina, Hall. Eleventh Ann. Kept. State Geologist Indiana, p. 299, pi. xxv, figs. 8-12. 1882. Hliitjieldia, Davidson. British Silurian Braohiopoda, Supplement, p. 107. 1889. Meristina, Nettelroth. Kentucky Fossil Shells, p. 101, pi. xxix, tigs. 7-10. 1889. Whitfieldia, Beecher and Clarke. Memoirs N. Y. State Museum, p. 73, pi. vii, tigs. 1-3. Diagnosis. Shell biconvex, the greatest depths of the valves being subequal. General expression meristoid. The beak of the pedicle-valve is erect in youth, but so greatly incurved at maturity as to totally conceal the foramen and deltidiuni. Cardinal slopes narrow but distinct, forming prominent slioul- ders which may be traced nearly to the middle of the lateral margins. A low, often indistinct median ridge extends from the apex forward ; at about the middle of the shell it is divided by a faint groove, becoming broader toward the margin and continued into a subnasute extension. Lateral slopes scarcely depressed. The brachial valve also bears a low median ridge, wliich manifests itself most conspicuously over the anterior portion of the sliell. On the interior of the pedicle-valve the teeth are conspicuous and are sup- ported by thin plates, which extend to the bottom of the valve and are produced forward to form the lateral boundaries of the muscular area. Between the posterior portion of these plates lies the deep scar of the pedicle muscle, which is separated from the elongate and radially striate diductor impression by a prominent callosity. In the brachial valve the hinge-plate is deeply divided in the middle by a narrow sulcus, the two lateral lobes being elevated, and supporting the crural bases. The plate is thickened on the under side and supported by a median septum, which extends for one-half the length of the valve. The crura are short and straight, and the primary lamellae of the spiral ribbon originate from them at a sharp angle, diverge laterally as they turn downward, passing over a portion of the secondary volutions, approach each other toward the middle of their length, nearly meeting at the anterior edge of the median septum, thence again diverging to their anterior recurvaiure. The secondary volu- tions do not follow precisely the curvature of the primary lamellse and the resultant cones at maturity have a gracefully undulated surface. The loop BRACHIOPODA. 67 consists of two lateral branches, broad at their origin, inclined backward, and uniting to form a stem which bears a short bifurcation at its extremity. The muscular area is elongate-ovate and more or less distinctly separated into anterior and jjosterior scars. Surface of the valves smooth or with fine concentric growth-striae. Shell-substance fibrous, impunctate. Type, Merisiella Maria, Hall. Niagara group. Observations. The name Meristina, proposed in Volume IV of the Palaeon- tology of New York (p. 'j!99), was introduced for the purpose of distinguishing from Mekistella a species, M. Maria, Hall, which possesses strong meristelloid characters but lacks the peculiar loop of that genus. Though the loop was im- perfectly represented in the figure accompanying the first use of the name, it nevertheless constituted then, as it still does, the single important difference of the species from Meristella. The precise character of this loop was fully determined subsequently (as described and illustrated in the present work), by the Rev. Norman Glass, Irom specimens obtained at the celebrated locality, Waldron, Indiana,* and described by Dr. Davidson in 188'2.f Mr. Glass found a loop of like structure in the English ( Wenlock) examples of the Atrypa tumida, Dalman. In the place cited Dr. Davidson expresses his conviction of the identity of the American species M. Maria with Atrypa tumida, and as the form of the loop then determined was new, he proposed to distinguish these fossils by the generic name Whitfieldia. It is to be regretted that the laws of nomenclature do not permit the admission of this name. Whether or not Dalman's species and the American M. Maria be conspecific, :]: they are at all events congeneric, and belong to the much earlier genus, Meristina. That this genus was imperfectly described * Though this species is a rare fossil in the Niagara fauna of New York, it is very abundant at Waldron and far fi'om infi-equent in the Niagara dolomites of northern Illinois and southei-n Wisconsin. t Silurian Supplement, p. 108, pi. v, fig'. 6. I We do not follow Mr. Davidson in reg.irding these forms identical. They jiresent differences which though slight, are positive and permanent variations of the same type of structure. A series of Gotland specimens of Atrypa tumida, obtained from, and identified by Dr. Lindstro.m, and submitted for our exami- nation by Mr. Charles ScHncHERT, shows that there are two readily apparent variations in the foi-ms refer- red to the Swedish species, and it is an interesting fact that these are from different localities. One of these forms (fi'om Westeigarn) is of small size, strikingly subpentagonal outline, with high, strongly arched and nari'ow umbo on the pedicle-valve, the greatest diameter of the shell being ^in front of the middle ; while 68 PALAEONTOLOGY OF NEW YORK. will not justify its overthrow, as long as the type-species is a well known form whose structure is now thoroughly understood ; and as Meristina is a term which has come into quite general use, it may not be cast aside for a later term. Accepting the foregoing interpretation of the characters of Meristina, we find but very few species which may be classed with those already discussed. The form described by Billings as Athyris Blancha, from the peculiar fauna of Square Lake, Maine (which contains, as far as known, a commingling of fossils elsewhere characterizing the Lower and Upper Helderberg horizons), seems to be a species closely allied to Meristina tumida, more so than to M. Maria. Its expression is unlike that of Meristella, though the character of the loop is undetermined. To the representatives of Meristina must be added the little Fio. 62. Fig. 53. The primary lamellsa and loop of Meristina rectirostra. Hall. IC.) species Meristella rectirostra, Hall, from the Niagara fauna, a form which has the bifurcated loop, but is peculiar in the immature expression of its adult charac- ters, namely, very small size, high, erect beak and unclosed delthyrium. the other (from Frojel) is of larger size, transversely subelliptical in outline, with low, broad, and slightly incurved be.ak. It appeai-s from Mr. Davidson's figures (Silurian Brachiopoda, pi. xi), that both forms occur in the English faunas. The characters of the American species differ from those which the Swedish and English specimens possess in common, in the following respects; (a) the abruptness of the cardinal slopes; (b) the obsolescence or absence of a median groove ovei' the anterior portion of the brachial valve and its lesser development in the sinus of the pedicle-valve ; (c) the general habit of the American species is uniform and its expression that of neither of the variations of the Swedish species just described, but of an intermediate character. The American form thus varies to such a degree that, while recognizing it as the representative of Atrypa tumida, it will serve a useful purpose to retain the original specific name. BRACHIOPODA. 69 Some interesting observations have been made upon the development of the brachidium in Meristina Maria, which may be introduced in thi.s phice ; it is probable that the facts observed are equally true of all the athyroids * In the youngest condition of growth at which the spirals have been demon- strated (a shell with a length of 7 mm.) the ribbon makes six volutions (see Plate XLI, figure 9). The primary lamellse are far stronger than the remain- der of the ribbon, indeed it is often only these that can be detected, the rest of the coil being exceedingly delicate and leaving but a linear trace in the calcare- ous preparations. The cones are very depressed, in fact are coiled almost in the plane of the first volution, and their apices are far back of the transverse axis of the shell, which is not the case in the adult, where they lie in, or slightly in front of this axis. The second volution of the ribbon is scarcely more than one-half as long as the first, and the third stands in the same relation to the second. In these early stages of growth it has been impossible to determine fully the condition of the loop ; it appears to be without the terminal bifurca- tion, and it is possible that this character was still undeveloped, though its absence may be accidental. In a later growth-stage (see Plate XLI, figure 10) the ribbon has greatly increased the number of its volutions, and the apices of the cones are more nearly central, but the cones themselves are still greatly depressed. The process of change from the primary condition of the spirals to their adult character was undoubtedly a complicated one, involving the con- stant resorption of the calcareous depositions made during the earlier stages. Attention may be directed to the effects of an accidental lesion or obstruction to the normal growth of this shell and its effect upon one of the spirals ; the ribbon has adjusted itself with nicety, and probably without the disturbance of function to the contracted and irregular cavity of the valves. * Observations of similar impoi-t liave been maiie upon the development of the spirals in Bhynchospira evax. Hall ; see Beechbr and Clarke, Memoirs of the INew York State Museum, vol. i, No. 1, p. 60. 1889. 70 PALEONTOLOGY OF NEW YORK. MERISTA, SuEss. 1851. PIRATE XLVI. 1851. Merista, Suess. Branhiopoden der Koessener Schichten, p. 17, pi. i. 1851. Merista, Suess. Jahrb. der k. k. g-eolog-. Reichsanst, vol, iv, p. 150. 1856. Merista, Suess. Classification der Brachiopoden von Th. Davidson, \>. 85, pi. iii, figs. 18-20. 1859. Camarium, Hall. PaliEontology of N. Y., vol. iii, pp. 486-488, pi. xcv, fig-.". 2-6. 1859. Camarium, Hall. Twelfth Rept. N Y. State Call. Nat. Hist., p. 42. 1860. Merista, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., pp. 73, 93, figs. 10-13. 1862. Camarium, Hall. Fifieenth Rept. N. Y. State Cab. Nat. Hist., pp. 176, 181, figs. 10-13. 1867. Merista, Hall. Twentieth Rept. N. Y. State Cab. N.-it. Hist., p. 258. 1881. Merista, D.avidson. Geological Magazine, new series, vol. viii, p. 289. 1882. Merista, Davidson. British Silurian Brachiopoda, Supplement, p. 103, pi. v, figs. 10-13. Diagnosis. Shells transverse or elongate, l)oth valves generally inflated ; anterior margin sinuate, producing a fold and sinus on the marginal portion of the brachial and pedicle-valves respectively. In the pedicle-valve the apex is perforated by a circular foramen, which, however, is usually concealed at maturity, by the incurvature of the beak ; deltidial plates rarely retained. On the interior the teeth are prominent and are supported by dental plates which extend either for a short distance into the interior cavity or are considerably produced at their bases as thickened ridges. Between the dental plates is an arched free plate (the " shoe-lifter " process) attached by its posterior and lateral margins, but at its anterior mar- gin extending beyond the dental lamellae and rising in a low, broad curve. In rare instances this process, from its origin, bears a sharp median carina which makes the anterior margin highly angulate. The muscular area appears to be limited to the space between the dental lamellae and to the surface of the " shoe-lifter." In the brachial valve a median septum is more or less strongly developed,* and divides a simple ovate adductor impression. The hinge-plate is short and deeply divided by a median groove. The brachial supports consist of spiral cones with their bases in apposition and parallel to the axial plane of the shell, and * In the figures of Merista hertiilea, Barrande, the type-species, given by Mr. DAvrosoN (Supplement British Silurian Brachiopoda, pi. v, figs. 10, 13), no evidence is seen of this dorsal septum ; it appears, bow- ever, in Babbande's figures, lioth of this species and of M. passer, Barrande (Systeme Silurien, vol. v, pis. X, xiii, xiv), 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 arras. 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. Fig. 61. The spirals and loop of Merista herculea, Barrande. (After Davidson, from a prepara- tion by Glass.) Type, Terebratula herculea, Barrande. Etage E. 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. Tennesseensis, 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 King 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 Camarium, Hall, was proposed for Merista ti/pa {= 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 Meristella, 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 ( = M. 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 doubt that this plate in Merista is quite analogous to the supported spondylium of Pentamerus, Camarophoria, etc., as well as to the platform of the Trimerellit. N. Y. State Cab. Nat. Hist., pp. 74, 84, 93, tigs. 5-9; p. 95, tigs. 1-5. 1860. ^Mv/ri.? .', Billings. Canadian Journal, [vol. v, new ser., p. 279, p. 274, tigs. 29-32; p. 281, tigs. 43, 44. 1S61. Meristella, Hall. Fourteenth Kept. N. Y. Slate Cab. Nat. Hist., p. 100. 1862. Meristella, Hall. Fifteenth Rept N.Y. State Cab. Nat. Hist., p. ItiO, figs. 17-22, pi. iii, figs. 21, 22. 1863. Meristella, Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist., p. 50, figs. 27-34. 1863. Meristella, Hall. Amei-iean Journal of Science, vol. xxxv, p. 396; vol. xxxvi, p. 11. 1863. Meristella, Hall. Transactions of the Albany Institute, vol. iv, pp. 139, 140. 1863. Atliyris, Billings. Pj-oc. Portlanella. We are not, however, satisfied that the entire process is here retained, but enough is preserved to indicate that it may have been unlike that of Merista and Meristella. In tlie form of the shell itself there is an excellent ground for upholding the name Pentagonia, and as this is enforced by the character of the hinge- plate and probably, also, by that of the loop, the term may safely be adopted, though the genus has but a single known representative. For this two varietal names have been used ; (a) uniplicata, for the form with one pair of flanges on the brachial valve, (b) biplicata, for that in which these tianges are duplicate.* The specimens from the Corniferous limestone of New York and the Falls of the Ohio, appear to be always of the uniplicate form, while in the Hamilton group, though the species is of much less fi*equent occurrence, both vai-ieties are present. The characters of Pentagonia, so far as known, ally it most nearly with MERISTELLA.f * It is obvious that the tirst of these names, as it ajiplies only to the typical form of the species, may be rejected ; the laUer it will prove useful to retain. t The name Gonioccelia, Hall, which was sugrgested in 1861 for the Alry^ta anlsulcata (Fourteenth Re- poi't New York State Cabinet of Natural History, p. 101), is an exact synonym for Pkntagonia, and may, therefore, be stricken from the list of gener.a. 82 PALEONTOLOGY OF NEW YORK. Genus CAMAROSPIRA, gen. nov. PLATE XLir. 1867. Camarophoiia, Hall. Palseontology of New York, vol. iv, p. 368, p), Ivii, figs. 40-45. Shells essentially meristelloid in external and internal characters. The important difference from allied genera lies in the fact that the dental plates of the pedicle-valve, instead of resting upon the bottom of the valve, are more strongly convergent than in Merista, Meristella, etc., uniting before they reach the internal surface of the valve, thus restricting the impression of the pedicle-muscle to a distinct chamber or .spondylium, which is supported by a low median septum. In the typical species (C. eucharis, Hall) this chamber has the same extent as the deep pedicle-cavity in Meristella, that is, about one-fourth the length of the valve, while the septum ex- tends for a short distance beyond its anterior margin, dividing the scars of the adductor and diductor impressions. In this respect the internal structure of this valve is similar to that of the corresponding valve of Pentamerus. In the brachial valve the hinge-plate is supported by a median septum slightly longer than that of the opposite valve, and the narrow, cordate mus- cular impression, which it divides medially, is considerably thickened. The valve bears everted spirals similar to those of other members of this group, but the specimens studied were not in a condition of preservation adapted to the determination of the structure of the loop. The only species known to possess the peculiarities described is the Camaro- phoria eucharis, Hall, from the Corniferous limestone of Indiana and the Province of Ontario. BRACHIOPODA. 83 Genus ATHYR IS, McCov. 1844. PLATliS XLV, XLVI, XLVII. 1S31. Terehratida, Eaton. American Journal of Science, vol. xxi, p. 137. 1S3'2. Tcrebratula, Eaton. Geological Text Book, p. 46. 1S38. Airypa, Conrad. Second Ann. Rept. Geol. Survey of N. Y., p. 111. 1842. Terehratula, d'Ohbig.my. Voyage dan.s I'Anierique Meriilionale, Pal. i>. 46, pi. iii, fig.s. 17-19. 1813. Atrypa. Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 198, tig. 5; Table."! of Organic Remains, No. 65, tig. 5. 1S44. Atliijris, Aiiiinouonclms, Seminnla, McCoy. Synopsis Cai-bon. Foss. Ireland, pp. 128, 146, 149, l.i8. 1847. Spirigera, d'Orbiuny. Comptes i'endu.s, vol. xxv, p. 268. 1850 Athyris, Cleiuthyris, King. Permian Fossils of England, pp. 136-140, pi. x, tig.s. 1-10. 1850. Spirigei'a, d'Orbiony. Annates des Sciences Nat., vol. xiii, p. 337. 1852. Terehratula, Hall. Stansbury's Expl. and Survey of the Valley of the Great Salt Lake, Utah, p. 409, pi. iv, figs. 1, 2. 1853. Terehratula, Shumakd. Mai-cy's U. S. Expl. of the Red River of Louisiana, p. 202, pi. iv, tig. 8. 1855. Terehratida, Schikl. Pacific Raili-oad Reports, vol. ii, p. 108, pi. i, fig. 2. 1856. Terehratula, Hall. Pacific Railroad Repoi-ts, vol. iii, p. 101, pi. ii, figs. 3-5. 1857. Spirigera. Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., p. 153, figs. 1, 2. 1857. Athyris, David.son. Monogr. Brit. Permian Brach., pp. 20-23, pis. i, ii. 1858. Athyris, Davidson. Monogj-. Bi-if. Carljon. Bracli., pp. 77-87, pis. xv. xvi, xvii, xviii. 1858. Terehratida, Spirigera {Athyrin), Hall. Tran.sactions of the Albany Institute, vol. iv, pp. 7, 8. 1858. Terehratida, Marcou. Geology of North America, pp. 51, 52, pi. vi, figs. 9, 10. 1858. Spirifera, Rogers. Geology of Pennsylvania, vol. ii, jiart ii, p. 828, fig. 667. 1858. Athyris, Hall. Geol. Survey of Iowa, vol. i, part ii, pp. 600, 659, 702, 703, 714 ; pi. xii, fig. 6 ; pi. xxiii, figs. 4, 5 ; pi. xxvii, figs. 1, 2. 1859. S]nrigera, Meek and Hayden. Proc. Acad. Nat. Sci. Philadelphia, vol. iii, sec. ser., p. 20. 1860. Athyris, Meek and Worthen. Pi-oc. Acad. Nat. Sci. Philadelphia, vol. iv, sec. ser., p. 451. 1>G0. Athyris, White. Journal Boston Soc. Nat. Hist., vol. vii, p. 229. 1860. Athyris, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., pp. 73, 89, 93, figs. 1-47, i>. 94. 1860. Athyris, McChksnby. New Paleozoic Fossils, pp. 46, 47, 80, 81. 1860. Athyris, Billungs. Canadian Journal, vol. v, p. 273. 1860. Spirigera, Swallow. Trans. 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, Saltek. Quai-t. Journal Geol. Soc. London, vol. xvii, \>. 64, pi. iv, fig. 4. 1861. Athyris, Billings. Canadian Journal, vol. vi, pp. 138, 145, figs. 54-57. 1861. Athyris, McChesney. New Palaeozoic 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. Stale Cab. Nat. Hist., p. ISO, figs. 1-4 ; pi. iii, figs. 10-13, 15, 16, 24. 1862. Athyris, Billings. Palseozoic Fosssils, 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. Winchell. 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. Athyrii, Davidson. Monogr. Brit. Devon. Brach., p. 13-19,pls. iii, iv. ? 1865. Athyris, Shaler. Bull. Mus. Comparative Zoology, No. 4, p. 69. 1865. Spirigera, A. Winchell. Proc. Acad. Nat. Sci. Philadelphia, vol. ix, i)p. 117, 118. 1866. Spirigera, A. Winchell. Geol. Rept. of the Lower Peninsula of Michigan, p. 94. 84 PALEONTOLOGY OF NEW YORK. 1866. Afhyris, Meek and Worthen. Geol. Survey of Illinois, vol. ii, p. 2.')4, pi. xviii, fig. 8. 1866. Athyrls, Gbinitz. Carbon und Dyas in Nebraska, pp. 40, 42, pi. iii, 6^s. 7-9. ? 1866. Athyris, Billings. Catalogue Silurian Fossils of Antioosti, pp. 47, 48. 1867. Athyris, Hall. Twentieth Kept. N. Y. State Cab. Nat. Hist., pp. 152, 2.^8. 1867. Athyris, Hall. Paleontology of N. Y., vol. iv, pp. 282-293, pis. xlvi, xlvii, figs. 1-33. 1867. Athyris, Hall. American Journal Science, vol. xliv, p. 48. 1868. Athyris ? McChesney. Trans. Chicago Acad. Science, vol. i, p. 33, pi. vi, tig. 4. 1869. Spirigera (Athyris), Toula. Sitzungsb. dei- kais. Akad. der Wissensch., vol. Hx, p. 6, pi. i, fig. .-;. 1871. Athyris, Meek. Haydens U. S. Geol. Survey of Nebraska, p. 180, pi. i, fig. 12; pi. v, fig. 8 ; pi. viii, fig. 4. 1873. Athyris, Meek and Wouthen. Geol. Survey of Illinois, vol. v, p. 570, pi. xxv, tig. 14. 1874. Athyris, Derby. Bulletin Cornell University, vol. i, pp. 7, 10, pi. i, fig. 6, 8; pi. ii, figs. 9-12 ; pi. iii, figs. 8, 15-21, 29 ; pi. vi, figs. 2, 16 ; pi. ix, figs. 4-6. 1875. AUiyris, Mekk. Palajontology of Ohio, vol. ii, p. 283, pi. xiv, fig. 6. 1875. Spirigera, '^MYrs. Wheeler's Expl. and Survey "West of the 100th Meridian, vol. iv, pp. 91, 92, 141 ; pi. V, figs. 11, II ; pi. x, figs. 5, 6. 1S76. Athyris, Meek. Bull. U. S. Geol. Survey of the Ten-., vol. ii, pi. i, fig. 2. 1876. Athyris, Derby. Bull. Mus. Comparative Geology, vol. iii, p. 279. 1876. Athyris, Meek. Simpson's Rei>t. Expl. Great Basin of the Terr, of Utah, y. 350, pi. ii, fig. 4. 1877. Athyris. Hall and Whitfield. 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. Athyris, Meek. King's U. S. Geol. Expl. 40th Parallel, vol. iv, pp. 81-83, pi. viii, fig. 6 ; pi. ix, figs. 3, 4. 1878. Athyris, Dawson. Acadian Geology, third ed., p. 290, fig. 88. 1880. Athyr'cs, White. Second Ann. Rept. Indiana Bureau of Statistics and Geology, p. 502, pi. iv, figs. 8, 9. 1881. Athyris, White. Tenth Rept. State Geologist Indiana, p, 134, pi. iv, figs. 8, 9. 1882. Athyris, Whitfielp. Bulletin Ameiican Museum of Natural History, vol. i, pp. 49, 50, pi. vi, figs. 18-27. 1883. Athyris, Hall. Twelfth Report of the State Geologist of Indiana, pp. 328, 329, pi. xxix, figs. 18-27. 1884. Athyris, White. Thirteenth Rept State Geologist Indiana, p. 136, pi. xxxv, figs. 6-9. 1884. Athyris, Walcott. Moiiogr. U. S. Geol. Survey, vol. viii, pp. 148, 222, pi. xviii. fig. 5. 1884. Athyris, Worthen. Bull. Illinois State Mus. Nat. Hist., p. 24. 1887. Athyris, Herrick. Bull. Denison University, vol. ii, p. 44, pi. ii, fig. 23. 1888. Athyris, Kbyes. Proc. Acad. Nat. Sci. Philadelphia, p. 10. 1888. Athyris, Herrick. Bull. Denison University, vol. iii, p. 49, pi. ii, figs. 1, 7; vol. iv, pp. 14, 24, pi. iii, fig. 6. 1889. Athyris Nettelrotu. Kentucky Fossil Shells, p. 87, pi. xvi, figs. 25-32. 1890. Athyris, Worthen. Geol. Survey of Illinois, vol. viii, p. 103, pi. xi, tig. 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 (wliich are frequently very indistinct) and nar- row, cordate adductors. The pallial i-egion 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 (visceral foramen), 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 outline of the hinge-plate is rendei'ed 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 lamellaB arising from their extremities, make an angular curve at their origin, thence, in the typical species, curving deeply 86 PALMONTOLOGY 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 hall' of the primary lamellae, the FIO. 57. Diagram of the structure of the brachidium in Athyris. X. Spiral coil. s. Saddle. a. Primary lanielliB of spiral coil. m. Fimbriated extensions of saddle. a^. Secondary Ianiell '/ v^ 0 o sy'' Fig. 68. yiQ 59 Fig. 5S. Vertical section of Athyris mbUlita, Hall, just back of the loop ; showing the crura (c) and the accessory Fig. 59. Vertical section of Athyris subtilita, Hall, through the stem of the loop. This view shows the great width 01 the primary lamella), the inclination of the accessory lamella (a, a) to them, and the thickened inner edges of the secondary lamellaj. (Cj 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 strias, 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 Athyris, 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 Athyris 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 PALEONTOLOGY OF NEW YORK. o-rowth, developed earlier in some species than in others, and hence the term was essentially a misnomer. On this account some authors, particularly the French and German writers, have preferred to use the term Spirigera, pro- posed by d'Orbignv in 1847* to replace Athyris, and founded on the same species. The term Euthvris, also, was proposed by the late Professor Quen- STEDTjf 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.| 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 pecti?iifera, 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. (h) 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 rendus, vol. xxv, p. 268. t Petrefactenkunde Deutschlands, p. 442. 1871. J Students who may wish to follow the vai'iation of opinion in regard to the value of the genus Atutris, are referi-ed to a paper by the late Mr. Billings, Palaeontologist of the Geological Survey of Canada, " On the Classification of the Subdivisions of McCoy's .Genus Athyris, as determined by the Laws of Zoological Nomenclature ; " American .Tournal of Science, vol. xliv (1867), p. 48. See, also, vol. xxxiii of the same Journal, pp. 127, et seq. § British Permian Biachiopoda, p. 21. BRACHIOPODA. 89 absent, probably from abrasion, on the earlier portions of the shell, and, as already observed, are frequently entirely lost. {c) 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. {(l) 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 lamellae being at or in front of the middle of their length. Fig. 60. Fig. 61. The crura and loop of Athyris spiriferoides, Eaton. (C.) (/) The saddle of the loop is broad and undivided at its anterior extremity. (g) The arms, or accessory lamella of the loop, are narrow. {h) The saddle, accessory lamellse and spiral bands are without spinules or fimbria. Fig. 63. The crura and loop of Athyris vittata, Hall. Fig. 63. (c.) Of American species which are referable to this typical division of Athvris, may be cited: A. spiriferoides, 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, and A. spiriferoides, Eaton, in Volume IV of the Palsontology of New York. 90 PALEONTOLOGY OF NEW YORK. group ; A. Cora, Hall, of the Hamilton group ; A. vi'tata* Hall, of the Cornifer- ous limestone and Hamilton group; A. Angelica, Hall, of the Chemung group; A. lumellosa, Leveille, of the Waverly and Keokuk groups ; A. incrassata, Hall, of the Burlington limestone, and A. Hannibalensis, Swallow, of the Choteau limestone. Subgenus CLIOTHYRIS, King. 1850. This name was introduced by Professor Phillips, in 1841,f as a substitute for Dalman's term Atrypa, which this author did not regard as appropriate. The term was 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 pedinifera, J. de C. Sowerby. His description was : " Generally lenticular in form ; minutely punctured ; with variously characterised projecting laminae of growth ; Spirals 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. King 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. Atrypa 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 orbiculai- and retaining- but traces of the laminffi. The species present variations which are included by European palaeontologists within the limits of Athyris coiictntrica, von Buch. t Paleozoic Fossils of Cornwall, Devon and West Somerset, p. 55. X The Permian Fossils of Eng-land, 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. FIG. 64. The fimbriated spirals ot Athyris pectin- t/"«-<», 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 differences 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 Ornat.e, 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. globulina), 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. * Pi-oductus limestone Fossils, p. 473. 1883. 92 PALEONTOLOGY OF NEW YORK. Subgenus 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. cil, 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' Spirifera (^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 expansionsf 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, for 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 lamellae fronting the sides of the shell " (Davidson). Athyris planosulcata is a species * McCoy afterwards referred the species to the grenus Athyris : British PaL-eozoic Fossils, p. 436. 1855. t See Davidson's superb figures in Carboniferous Brachiopoda, pi. xvi., figs. 7, 8. i 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 SEMINULA, McCoy. 1844. This is another term proposed in the " Synopsis of the Carlwniferous 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 plaits 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, f 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 Hunteriaii 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 lamellae is of the same character as in Cliothyris, etc. The primary lamellae, 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 fig. ss. , . . Loop of Athyris trinuclea, both it and the outer margins of the ribbon of the sec- naii. m- i-ouis ime- -, . r, • Stone. (c.) 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 lamellag. 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, Alhyris sub- quadrafa. Hall; A. trinuclea. Hall, of the St. Louis limestone; A. Daivsoni, sp. nov.,* of the lower Carboniferous beds of Windsor, Nova Scotia; and A. sub- tilita, Hall,f of the upper Carboniferous. Tn 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. FIG. 67. The loop of Seminula subtilita, Hali. (C.) 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 Davidson as A. subtilita. See Quarterly Journal Geolog-ical Society, vol. xix. t Athyris subtilita is a protean species, some of whose variations in g-eneral form are illustrated en the accompanying- plates. One feels at tirst disinclined to include under the same sjiecific designation the broadly ticiform, the narrow elongate, the sinuate, non-sinuate, and trilobed shells which are customarily thus referred ; but very abundant mateiial shows the difficulty of separating 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 m.ay have a more or less important faunal or geological value. For example, the most abundant representative of the species occurring in the upper Coal Measures about Kansas City, is a narrow, elongate, slightly sinuate shell, one extreme of variation ; again, we have been supplied by Professor S. Calvin with a series of specimens from Winterset, Iowa, some of which are as deeply trilobate on the anterior margins as extreme forms of A. siibquadiata ; 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 occurs a form which it is impossible to sejiarale from A. svhtillta ; 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 lamellse 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 br.anches 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 Athyris oxycolpits, Emmrich. (ZlTGMATEB.) Fig. 69. Fig. 70. Fig. 71. The loop of Athyris (Seminula) Dawsoni, sp. nov.; showing the variation in devclopniont of the saddle in different individuals. Fig. 70 is a view from the umhonal region of the specimen represented in Fig. 69, indicating the marginal position of the accessory lamellse 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 lamellse, as shown in the accompanying figures, lie upon the inner edges of the primary * Zugmayer, Untersuchungen ueber rhaetische Brachiopoden ; Beitiaege zur PalEeontologie ffisterreich- Ungai-ns und des Orients, pi. iii, figs. 21-23, and p. 353, figs. 1-3. 1SS2. BRACHIOPODA. 97 lamellae, and not between the primary and secondary lamellge as usual ; further- more, these accessory lamellaB are very narrow.* While from our present knowledge the group of Seminui.a nuist 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 York, which has many of the internal shell-characters of A. suhtilita. This species, Athyris Rogem,f sp. nov., occurs in the condition of internal casts which show tlie 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,J which seemed to show the existence of accessory lamellae. This little shell has recently been closely investigated by the Pvev. Norman Glass,§ who finds that the loop forms no saddle, and that the intercalary lamellae are * 111 the progress of this work some shells were received from a colleclion formei-ly belonging to the Rev. H, Herzbr, of Berea, Ohio, bearing the label "Athyris aiiibigua, Cork, Irelaml." The specimens possess a rather more transvei-se form than usual in A. ambigua, and the faint cancellation of the exfoliated sui-face would indicate that it was originally spinous oi- lamel- lose. It is evident that the species is not A. ambigua, but its specific 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 umbonal region. The lateral branches originate from the pi imary lamellae 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 crura and hav- ing a slight curvature. The saddle is entire on the anterior margin and not fimbriate. t Named for Di-. Benjamin Rogers, of Pendleton, in recognition of his intei-est in the development of the fauna of this locality. I British Silurian Brachiopoda, Supplement, p. 101, pi. iv, figs. 24-2(). § Geological Magazine, Dec. Ill, vol. viii, p. 495. 1891. FIG. 72. Loop of Athyris, sp. ?, Carbonilerous limestone, Cork (?). (C.) 98 PALAEONTOLOGY OF NEW YORK. short compared with those of a typical Athyris and make but a short curve within the primary lamellte. A very peculiar feature of this structure is the absence of an upright athyroid stem, the bifurcation of the intercalary lamellai taking place at the point of union of the lateral supports of the loop, tlie 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, Whitfieldella, 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 as the shell certainly represents a distinct variation of structure from any heretofore observed, it will be far more satisfactory to recognize this fact l)y giving the species some distinctive term, as Glassina. Subgenus SPIRIGERELLA, Waagen. 1883. 1862. Athyris, Davidson. Qiiai'tei-Iy Journal Geol. Soc. London, voL xviii, p. 28, pi. i, fig'. 8. 1863. Athyris, De Koninck. Foss. Paleoz. de ITnde., p. 33, pi. ix, fig'. 8. 1867. Athyris, Vekchkre. Jour. Asiat. Soc. Bengal, vol. xxxvi, pt. ii, p. 210, pi. ii, tigs. I, 1 a. 1874. Athyris, Derby. Bull. Cornell University, vol. i, No. 2, p. 7, pi. i, fig. 7. 1883. fSpirigerella, Waagen. Palfeontologia 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 the Salt-Range. BRACHIOPODA. 99 ency to piano-convexity, the pedicle-valve being de- /\ pressed by a broad, flat sinus, and the brachial valve ^KJ/^ ^ considerably elevated ; the cardinal slopes are more \^br^=^^^***' or less pronounced ; the surface is smooth or with ^^^ .^ sharp, concentric growth-lines, which were not pro- ''""'' "' ^'""^"''"'' "^\\y'^^l'^l^"'' duced into lamellae or spines. On the interior the hinge-plate is high, the anterior face being erect, the upper fixce subquadrate in outline and concave, the posterior face 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 Derbiji, 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 S. alata, Waagen) ; while it eliminates the group of S. grandis {S. grandis, S. media, S. ovoidalis, S. fusiformix, 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 S. 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 Palaeozoic, 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 Spirigkra ( = 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. b. 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 ; Plicigera. 74. Fig. 7S. Fijf. 74. Tetractinella trigonella, Schlotheim. Fig. 75. Loop 01" Dioristella indistincta, Beyricli. Fig. 76. Amphitomella hemisphtBroidica, Klipstein. (UlTTNER.) * Brachiopoden der Alpinen Trias: Abhaiidl. der k. k. geolog. Reichsanst., Bnd. xiv. 1890. BRACHIOPODA. 101 ij. Tetractinella includes forms with four ribs on each valve. 6.,. Pentactinella includes those with five ribs on each valve. 6.5. 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. Orthis, Phillips. Palaeozoic Fossils Cornwall, Devon and West Somerset, p. 65, pi. xxvi, tig-. 110. 1842. Orthis, d'Archiac and de Vekneuil. Descr. Older Deposits Rhenisii Provinces ; Trans. Geo!. Society, London, sec. ser., vol. vi, p. 396. 1853. Orthis, Steininger. Geog-n. Beschreibung- der Eifel, p. 80, pi. v, tig. 5. 1864. Atrypa, Davidson. British Devonian Brachiopoda, p. 51, pi. x, fig. 1. 1871. Retzia, Quenstedt. Petret'actenkunde Deutschlands ; Brachiopoden, pi. li, tigs. 21-25. 1871. Retzia, Katser. Zeit.sch. der deutsch. geolog. Gesellsch., vol. xxiii, p. 161. 1882. Kayseria, Davidson. Devonian Brachiopoda, Supplement, p.'21, pi. ii, figs. 11, 12. Orthis lens, Phillips, the type-species of this genus, is a small middle Devonian shell, with depressed-conve.x 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. primary ribbon ; 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 lamelliB 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 lamelli^ pass between the first and second volutions of the princi- pal ribbon, and the two are intercoiled in this manner for their entire extent. Katseria is thus an athyroid with double spirals and the only species known FIG. 77. Approximate deteiminalion of the loop in Kfiyseria lens, Phillips. (c.l FIG. 78. FIG. 79. Fig. 78. PexideUa Strokmayeri, .Suess. "Fip. 79. IHplospirella Wissmanni, Miinster. (BiTTNER.) BRACHIOPODA. 103 in palasozoic faunas in wliich tlie 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 ; ciuctured 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 Kayseria 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. Terebmiida, de Vernecil. Ball, ile la Soc. g-eol. de France, second sei-., vol. xi, p. 471, pi. xiv, figs. 10 ad. 18S0. Retz'm, King. Monogr. Permian Foss. England, p. 137. 1854. Retzia, Davidson. Inti'od. British Fossil Brachiopoda, p. S8, jil. vi, tig. 77. 1886. Retzia. (Ehlurt. Annates Sci. Geol., vol xix. No. 1, p. 24, pi. xi, tigs. 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 Schichten von St. Cassian, Zweit. Abtheil., p. 28. 1865. Bbechbr, American Journal of Science, vol. xl, p. 211, pi. ii. 1890. 104 PALEONTOLOGY 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, EuMETRiA ; 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 referi'ed to Retzia. It will be necessary to determine the value of this genus from the characters of the species Terebratula Adrieni, 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 Adrieni 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, | 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 (Ehlert, 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 Socifite geol. de Fiance. 2d Ser., torn. 11, p. 471, pi. xiv, figs. 10, a-d. t See CEhlbrt; Etudes sur quelques Fosailes devoniens de I'Ouest de Fiance; Annales Sci. G6ol., t. six. No. 1, p. 24, pi. xi, figs. 11-19. 1886. X Appreciating the necessity of making a thorough study of this rare species, we twice applied to Ur. CEhlkrt for specimens, and he has most generously met tliese requests, not only with a number of examples from the Departement de la Sarthe, but with copies of unpublished sketches of sections. This generosity and spirit 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 deltidiuni 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 deltidiura. 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 Hustedia and Acambona, but it appears to be more highly developed and longer in Retzia than in either of these. 106 PALEONTOLOGY OF NEW YORK. FIG. 81. FIG. 83 Jietzia Adrieni, de Verneuil. FIG. 83. Fig. 84. Fig. 85. Consecutive sections to show internal structnie of the umbonal regions. Fig. 80. Figs. 80-85. Fig. 80. Outline of the shell, showing location of next three sections. Fipr. 81. Section across opening of foramen, with umbonal tube open on the back. Fig. 83. Section fm-tber down, showing attachment of the remnants of the tube to tbeilelticlial plates. Fig. 83. Section near the liinge, showing last traces of tube adherent to the thickened deltidial plates. Figs. 84, 85. Sections from another individual, one across the foramen, the other beneath it ; showing the continuity of the tube. (c.) V^ Fig. 86. FI0.'87. FIG. 89. Fig. 90. FiG. 91. Fig. 93. Fig. 93. Fig. 94. Fig. 96. Figs. 86-91 Fig. 97. Retzia Adrieni, de Verneuil. Fig. 98. Fig. 86. Section just below the foramen; showing the entire umbonal tube. Fig. 87. Showing the adherence of the tube to the still divided and discrete deltidial plates. Figs. 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 lamelbe, and the median septum in the brachial valve. Fig. 91. Section just above the ape.\ of the brachial valve; showing the Last traces of the deltidial plates, which are here free. Fig. 93. Section at the ajjcx of the brachial valve. ' Fig. 93. Section cutting the posterior extension of the median and lateral lobes of the binge-plate. Fig. 94. The same features further down; showing also the appearance of the teeth, and the remnantsof the dental lamellae bordering the muscular area of the pedicle-valve. Fig. 95. Section through the center of the hinge-plate; showing also the development of the dental sockets. Fig. 96. Section showing the ante-median crest of the hinge-plate. Fig. 97. The anterior edge of the hinge-plate .and its supporting septum. Fig. 98. Section in front of the hinge-plate; showing the crura and median septum. (c.) 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 umbonal 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 Husteuia ; 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 uppor face is convex and the later.al 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 lamellfB are comparatively narrow and considerably incurved at their apices, where attached to the long crura, as in Edmetria. The loop is situated well forward, just behind the center of the lamellae ;* its lateral branches are erect and long; they narrow with a slight twist just above their origin, as in the genera Rhynchospira and Trematospira, then broaden, curving outward and Fig. 99. Fi!. i, fig-. 1. 1872. Retzia, Meek. Hayden's U. S. Geol. Survey Nebraska, p. 181, pi. i, fig. 13 ; pi. v, fig. 7. 1874. Eumetria, Derby. Bull. Cornell University, vol. i, p. 4, pi. viii, figs. 4, 5, 7, 8, 10 ; pi. ix, fig 3. 1875. Terehratula, Marcod. Trans. St. Louis Acad. Sci., vol. iii, p. 252. 1875. Retzia, White. Wheeler's Geogr. Surveys West of 100th Meridian, vol. iv, pp. 141, pi. x, fig. 7. 1883. Eumetria, Waauex. Pala?ontologia Indica, ser. xiii, vol. iv, p. 487. 1884. Retzia. Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 220, pi. vii, fig. 5. 1884. Retzia, White. Thirteenth Ann. Kept. State Geologist Indiana, ji. 136, pi. xxxv, figs. 10-12. In external characters the shells constituting this genus are indistin- guishable from those of Eumetria, except in their much coarser plication. For this reason they have been classed under the latter genus by several writers, though the internal structure in the two groups is curiously distinct. While the complicated structure of the interior in Eumetria was not under- stood such an association of the species was altogether natural. The type of this new genus the Terehratula Mormoni, Marcou (= Retzia pundulifera, Shumard), — a characteristic species of the upper Coal Measures in both North and South America. The essential difference of this species from Eumetria vera lies in the * To the memory of the Honorable James William Husted, this interesting and widely distributed genus of Brachiopods is dedicated. A j)atron and promoter of science, who, during a period of more than twenty years, as Representative in the Assembly of the Legislature of New Yoi-k, zealously e.spoused the interests of the PaliEontology, and of every other department of the N.atural History of the State of New York. A wise legislator and educalo)-, a faithful and unswerving friend and counselloi- of many years, his name deserves 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 umbonal 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 Adrieni and Acambona Osagensis, though not so highly developed as in the first of these. This structure is of so frail a nature that it is difficult to preserve it in prepared inte- riors of the valve, l^ut it always reveals itself in ,^=5^ transverse sections of the beak near its apex. The Mj^ structure of the hinge-plate has been quite accu- outline pronie ofmisledia Mormoni. Mar- ■ 11 MiiT^ 3ifex» ii 'j.* /» cou, with enlarged transverse sections rately described by Derby* trom the interiors of „t the umbo beneaii, the foramen ; 7-, ,. J Tj- I TT i T Tl/T ■\ 1 i • 1 showing the internal tube adherent to Lumetna punctuLijera {= nusteaia Mormom) obtained iho coalesced iieituiiaipiates. (o 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-I The hinge-plate, as it appears in the preparations of Terebratula 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 Athyris, but it is evident from its * Bulletin Cornell University, vol. i. No. 2, pp. 5, 6. 1874. t Salt-Range Fossils ; Brachiopofla, p. 486. 1883. 122 PALAEONTOLOGY 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 Eu- METRiA, and Derbv has shown that the posterior margins of the coils are fimbriated. The loop, also, is quite similar to that of Eumetria Verneuiliana. Waagen has represented it in Eumetria (Hustedia) grandicosta, Davidson, as terminating in a short, Loopor iJusMJjiLmom.Marcou. lo sharp, retrally directed stem, but in the American specimens this stem appears to be much longer and the posterior edges of the lamellae both of the stem and the lateral branches are furnished with divergent spinules. In all our prepara- tions the extremity of the stem appears to be simple. The exterior of the shell is coarsely plicated and the structure strongly punctate. The representation of this genus of shells in American faunas is restricted, so far as known, to the species H. Mormoni*, which occurs in the upper Car- boniferous of Missouri and Kansas, and has been identified by Derby in the Coal Measures both of Brazil and Peru. The two species described by Waagen from the Salt-Range of India as Eumetria grandicosta, Davidson, and E. indica, Waagen, belong to Hustedia, and probably also Retzia (Terebratula) radialis, Phillips, Retzia carbonaria, Davidson, and R. (Terebratula) ulothrix, de Koninck from the British Coal Measures. Retzia ulothrix, R. radialis, R. Davidsoni, R. in- termedia, de Koninck, occur in equivalent faunasin Belgium.f It is probably true that the various species from the St. Cassian beds, which have been referred by BittnerJ to the genus Retzia, have their closest relations with Hustedia. These are, for the most part, coarsely ribbed forms, some of them with extravagantly high areas. Their internal structure has not been satisfactorily demonstrated. * Whether the other American Carboniferous species, Retzia compressa. Meek; R. Woosteri, White; R. Meekana, Shumard, and R. papWata, Shumard, are congeneric with H. Monnoni, is not yet deteimined. t See Davidson, Cartioniferous Brachiopoda, pp. 87, 88, 219, pi. xvii, figs. 19-21 ; pi. xviii, tigs. 14, 15; pi. 1, figs. 3, 4-9 ; and de Koninck, Faune du Calcaire Carboniffere de la Belgique ; Brachiopodep, Explic, pi. xxii, figs. 1-4, 10-19. t Brachiopoden der alpinen Trias, 1890. BRACHIOPODA. 123 Genus UNCINELLA, Waagen. 1883. PLATE LI. 1883. ?77jd7ieZZo, Waaobn. Memoii-s Geolofjical Survey of India; Palseontologia Iiidica, Siw. xiii ; Salt-Range Fos.sils, vol. i, p. 494. This name has been proposed for a single rare species, Uncinella indica, occur- ring in the middle division of the Productus limestone beds of India. Dr. Waagen has described the genus as follows : " In external shape the genus bears resemblance in a general way to Rdzia. The valves are niox'e or less finely plicated ; no sinus or median fold is devel- oped ; the hinge-line is curved ; the beak thick and strongly bent over, mostly appressed to the cardinal part of the dorsal valve ; not provided with an area on its dorsal side, but bearing a distinct deltidium. It is pierced behind the apex by a large oval foramen. The apex of the dorsal valve is very strongly bent over, and partly concealed under the apical part of the ventral valve." " * * * The shell bears spirals of the same general disposition as in Retzia or Uncites, but neither the loop nor the mode of junction of the primary lamellae with the crura could be made out definitely. In the ventral valve below the apex of the beak, there is an excavated, small but very distinct del- tidium ; its composition of two pieces cannot, however, be made out. It does not reach down to the hinge-line, but is cut out below for the reception of the apex of the small valve. On both sides of the deltidium extend along the curved hinge-margin two long ridge-like hinge-teeth. They are not supported by dental plates, and there is also not a trace of other partitions. Fig. 108. Fig. io9. Interior cardinal region of pedicle and brachiivl valves of Uncinella indica, Waagen. (Waagen.) " In the dorsal valve the apex is flattened, as if ground down, and bears a flat triangular space, as if for the insertion of muscles ; a cardinal process is not present. At the ape.x two sharp ridges take their origin, limiting the dental sockets on the other side. These latter are elongated, deep triangular 124 PALEONTOLOGY OF NEW YORK. grooves. There is no hinge-plate spread out between the sockets. The crura take their origin immediately at the apex, as thin, shelly plates sloping strongly toward the middle line, and thus very nearly reach the bottom of the valve. As far as the dental sockets extend, tliese crural plates are fastened to them. Lower down they become free, and then form rather broad, shelly blades, which always retain their sloping position towards the middle line of the valve. They are sunk deeply into the interior of the valve, extending not very far from the bottom of it." Shells of this structure are not as yet known in American faunas. Genus TREMATOSPIRA, Hall. 1859. PLATE XLIX. 1852. Atrypa, Hall. PaliEontoIogy of N. Y., vol. ii, p. 273, pi. Ivi, fig. 3. 1857. Spirifti; Hall. Tenth Kept. N. Y. State Cab. Nat. Hist., p. 59, figs. 1-6 ; pp. BO, 168. 1859. Trematospira, Hall. Twelfth Kept. N. Y. State Cab. Nat. Hist., pp. 27, 77. 1859. Trematospira, Hall. Palieontology of N. Y., vol. iii, pp. 207-212. 1860. Trematospira, Hall. Thirteenth Rapt. N. Y. State Cab. Nat. Hist., p. 82, pi. xxiv, fig. 3 ; pi. xxviiiA, figs. 1, 5. 1860. Athyriif, Billings. Canadian Journal, vol. v, p. 282, figs. 45-47. 1863. Trematospira, Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist., p. 54. 1863. RhynchoneUa, Billing.s. Geology of Canada, p. 315, fig. 322 ; p. 958, fig. 458. 1863. Mel.zia, Billlngs. Proc. Portland Society Nat. Hist., pp. 112, 113, figs. 8-10. (?) 1866. Trematospira, A. Winchell. Geol. Kept, of the Lower Peninsula of Michigan, p. 94. 1867. Trematospira. ll\hL. Palaeontology of N. Y., vol. iv, pp. 271, 272, 276, figs. 1-6; pi. xlv, figs. 7-15. 1884. Trematospira, Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 151, pi. iv, fig. 3. 1889. Trematospira, Nettelroth. Kentucky Fossil Shells, pp. 135, 136, pi. xvi, figs. 15-19. Diagnosis. Shells transverse, subequally convex, with median fold and sinus on brachial and pedicle-valves respectively. Surface covered with radial, coarse or fine, simple or duplicate plications. Hinge-line straight, often long ; cardinal extremities abruptly rounded ; anterior margin sinuate. Umbo of the pedicle-valve incurved, its apex truncated by a circular foramen. Beneath it lies the delthyrium, which is covered by two short incurved plates, more or less closely anchylosed along the median suture, and so greatly thickened on their interior surface as to appear continuous with the substance of the valve. This deltldial plate does not extend downward much more than one-half the distance from the apex to the cardinal margin, leaving beneath it a crescentic opening which is occupied by the beak of the opposite valve. On either side BRACHIOPODA. 125 of the deltidial plate is a narrow and rather abrupt flattening of the shell, suggestive of a cardinal area. The umbonal cavity is short and usually much contracted, leaving only a simple passage for the pedicle. The teeth are approximate and j^rominent, arising from the bottom of the valve, and above the hinge-line curved backward and toward each other, making a very close and firm articulation with the other valve. The dental lamellce are not continued along the interior of the valve. The muscular area is well defined and consists of a deep posterior area, in front of which lies a flabelliform scar, extending for fully one-half the length of the shell. In the brachial valve the beak is not prominent and the false area is absent. A small chilidium is present and lies against the vertical pos- terior wall of the hinge-plate. The hinge-plate is greatly elevated, rest- ing upon two stout supports which are placed very closely together, leaving no opening between them at the bottom of the valve. The upper face of the plate is quadrate, but very deeply divided by a median longi- tudinal groove, and less conspicuously, by a transverse groove ; the surface is thus divided into four parts, two posterior portions which extend backward into the umbonal cavity of the opposite valve, as short, stout horns, and two ante- rior processes which are broader but equally elevated, the crura arising from the ante-lateral margins of the latter. In the deep longitudinal cleft or groove of the plate is a short, convex lobe, terminating posteriorly in a simple or double extremity; sometimes this part is absent. The whole process is ren- dered more prominent by being slightly constricted about its base. It is sup- ported interiorly by a short median septum, which is frequently obsolete. The dental sockets are small and deep. The crura are broad, thin and compara- tively short, uniting with the primary lamellae in a sharp lateral curve without diminution or increase in size. The umbonal blades are not greatly incurved and are quite as narrow as any portion of the primary ribbon. The loop takes its origin well forward near the middle of the spiral cones ; the lat- eral branches are somewhat broadened at their origin, but become slightly constricted and twisted just above their bases, and then widen again, attaining 126 PALEONTOLOGY OF NEW YORK. their greatest width where they unite. From their line of union there is a short, acute and simple process extended horizontally backward. The attitude of the loop is erect, extending slightly back- ward at its base and then curving broadly forward Fig. 110. Loop ol' Trematospira mitlHstruita^ and upward ; in height, it reaches rather more than iiaii. ic ) half-way across the bases of the spiral cones. The cones are situated as in allied genera, and the ribbon in mature shells, makes nine or ten volutions. Muscular impressions indistinct. Shell substance punctate. Type, Spirifer multistriatus, Hall. Lower Helderberg group. Observations. Trematospira is well characterized in external features by its peculiar transverse form and general spiriferoid aspect ; none of the allied genera can be confounded with it in these respects. Internally the structure of the hinge-plate and loop, the character of the muscular area and the nature of the articulation are all peculiar. The name Trematospira was proposed for a series of species occurring in the Lower Helderberg fauna, some of which had been previously referred to the genus Spirifer. At the time of the description of the genus no particular form was specified as the type, but among the typical species the first mentioned was T. multistriata, Hall, although the first in the descriptive list is T. perforata, Hall.* The former is taken as the typical species, as it is better known and of more frequent occurrence ; T. perforata appears to be congeneric in all respects. The development of the Trematospiras in the Lower Helderberg fauna is remarkable ; we have in the New York launa, T. multistriata, T. perforata, T. costata, T. simplex, Hall, and from the Lower-upper Helderberg fauna at Square Lake, Maine, T. dubia, T. Hippolyte and T. Maria, Billings. In other faunas the genus is of rare occurrence. The Atrijpa camura. Hall, of the Niagara group {Trematospira camura, Hall, 1859), is a small species which is probably the earliest representative of the genus, as it is doubtful if the still earlier form, described as Retzia {Trematospira) granulifera, Meek,f of the * Palaeontolog'y of New Yoi-k, vol. iii, p. 208. t Palteontolof^y of Ohio, vol. i, p. 128, pi. xi, fig. 6. BRACHIOPODA. I'll Hudson River group of Cincinnati, should be thus referred. Mr. C. D. Wal- COTT has described a species, T. infrequens, from a lower Devonian horizon at Lone Mountain, Nevada;* and the latest representative of the group appears to be the T. gibbosa, Hall, of the Hamilton group, a form which is very strongly plicated, but presents no substantial generic differences from T. mul- tistriata so fixr as its interior is known. Several other American species have been referred to this genus, some of which are now known not to be congeneric (T. hirsuta and T. nobilis, Hall, of the Hamilton group); and others which can not now be placed with precision (T. Acadiai, Hall, Upper Silurian; T. Matthewsoni, McChesney, Niagara group ; T. liniuscula, Winchell, Hamilton group). European investigators have not satisfactorily identified the genus among their faunas. Genus PARAZYGA, gen. nov. PLATE XLIX. 1857. TVaWieimia, Atrypa, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. S9, 168. 1859. Treviatospira, Hall. Palseontolog-y of New York, vol. iii, p. 216, pi. xxxvi, fig'. 3. 1861. Trematospim, Hall. Fourteenth Ann. Rept. N. Y. State Cab. Nat. Hist , p. 101. 1562. Trematospira, Hall. Fifteenth Ann. Rept. N. Y. State Cab. Nat. Hist., pi. ii, figs. 11-16. 1563. Jietzia, Billinos. Geology of Canada, p. 385, fig. 419. 1867. Trematospira, Hall. Paleontology of New York, vol. iv, p. 274, pi. xlv, figs. 16-32. The well known species of the Hamilton fauna of New York, Airi/pa,j or TrematosphaX hirsuta, Hall, agrees with typical forms of Trematospira in the general transverse and medially sinuate character of the exterior, but differs in certain details of structure sufficiently to necessitate its removal from that genus. The surf\ice markings of the exterior consist of numerous fine, rounded, simple ribs, extending alike over median fold and sinus, and these are covered with exceedingly fine, short, hair-like spines, not so closely set nor so long as in NucLEOSPiRA. Usually these delicate spines are broken off", leaving only their bases, which indicate that the spines are hollow. The umbo of the pedicle-valve is closely incurved and the deltidium ( or coa- lesced deltidial plates) which is entirely concealed by the uniljo of the opposite valve, is usually lost. The apical portion of the umbonal cavity bears an * Paljeoutology of the Eureka District, p. 151, pi. iv, fig. 3. t Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 168. 1857. \ Palaeontology of New York, vol. iv, p. 274. 128 PALEONTOLOGY OF NEW YORK. introverted lamella which forms an incomplete tube like that in Retzia, HusTEDiA, etc., but of no great extent. The teeth are as in Trematospira and are supported by stout plates. The muscular area is short, rather well de- fined, and is divided into a broad central adductor impression, along the lateral margins of which lie two flabellate diductor scars. The hinge-plate is very narrow, and is composed of two vertical supports which have their origin on the downward umbonal slope of the interior. These supports are widely separated at their bases and inclose the marginal dental sockets ; their anterior faces are vertical and their upper surfjices small and sub-triangular. They do not unite with each other at any point, but each is curved slightly back of the cardinal line, and on its ante-lateral angle supports a crus. The loop is situated at about the center of the primary lamellae, bending backward for a short distance and then forward at an abrupt angle. Above this angulation its length is about twice that below it. It terminates as in Trematospira, in a short, sharp and simple hori- zontal process, directed posteriorly. Fi... m. Uoeof I'arazygahirsuta.U-M. 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 Palseontology of New York. There is but one other species which can properly be placed in the same association, namely, the Waldhei?nia or Trernatospira 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 species has also beea identified in the Corniferous limestone of Louisville, Ky., and elsewhere. t Named foi- the late Prof. Chester Dewey, of Rochester, N. Y. BRACHIOPODA. 129 differs from that of Parazijga hirsuia in having the lateral portions united hy a central lobe, and the entire process supported by a short, septiform median buttress. These dijBferences in the hinge-plate are of inconsiderable import- ance and the loop is essentially like that of P. hir- suta ; its posterior geniculation being more nearly at the middle of its length, the anterior bend shorter, the entire upper portion of the loop above the geniculation of the lateral branches being '"'"•"'•'•'""' ""''"■"^^^" ■^^■^;',"""- expanded laterally and the lamellas much broadened. Genus ANOPLOTHECA, Sandberger. 1855. PI.ATE LII. 1853. Terebratiila, Schnur. Besclir. der Eifel. Bracliiopoiien, p. 180, pi. xxiv, fig. 3. 1855. AnoplotTieca, F. Sandberger. Sitzung'sber. der k. k. Akad. der Wissensch. math, naturw. Clas?. pt. xvi, p. 5 ; pt. xviii, p. 102, pi. i, tigs- 1-6. 1856. Productiis, Anoplotheca, The Sandbergers. Vei'slein. des rhein. Schicht. syst. Nassau, p. ,351, pi. xxxiv, fig. 18. 1856. Anoplotheca, Suess. Classification der Brachiopoden von Th. Davidson, p. 94, pi. iii, fig. 26. This name was introduced by Dr. Fridolin Sandberger, who described, first in April, 1855, the general external and internal characters of the genus, and in November of the same year, gave a partial account of the brachial apparatus. The following description is a translation of that given by Suess in his German edition of Davidson's " Classification of the Brachiopoda," and is derived from the two accounts published by Sandberger. " Shell oval in outline, concavo-convex, without pedicle-opening, cardinal area or deltidium. The hinge-line is arched, the inner margins somewhat ele- vated and radially grooved by the impressions of the cilia of the mantle. The convex ventral valve is the larger. On its interior, near the hinge, lie two stout teeth ; along the median line from the beak, for one-half the length of the valve, extends a narrow ridge, which is divided at its lower extremity ; on either side of this may be seen the impressions of the cardinal muscle, and at its lower end the little ovate scar of the adductor. Near the upper end of the cardinal scar originates, on each side, the main trunk of the vascular sinuses, which passes rather obliquely toward the margins, but before reaching them sends off a trifurcate lateral branch toward the center, and is itself divided. 130 PALEONTOLOGY OF NEW YORK. . " The dorsal valve is not very concave ; its little cardinal process is divided, and is bordered on each side by a stout lamella, outside of these lying the deeply excavated dental sockets ; to these lamellae the two depressed spiral cones, with their many volutions, appear to be united ; both cones having the same position as in Koninckina [ ? J. Beneath the cardinal process, and on either side of a thick median septum, lies a broad, oval impression of the adductor muscle, which is divided by a more or less prominently developed oblique ridge ; from the upper and lower margins of this impression originate the vascular sinuses which are directed toward the edges of the valve. A small, round, deep im- pression beneath the cardinal process is, at present, not understood ; it lies at the spot where presumably the curvature of the alimentary canal occurred. Shell-structure fibrous, irapunctate." The type of this genus is the little Produdus lamellosus, Sandberger,* which is conceded to be synonymous with Schnur's Terehratula venustaf from the middle Devonian of the Eifel. From Schnor's description of the species we derive a more detailed account of the external sculpture of the shell than that given by Sandberger and Suess. The shell is small, concavo-, or plano-convex, with incurved umbo, open, or but partially closed delthyrium and no cardinal area. " On the pedicle-valve is a narrow median groove separating two broadly rounded plications which bifurcate near their origin at the beak, and disappear near the middle of the valve ; on each lateral slope are three additional and smaller plications which also disappear before reaching the anterior half of the shell. There is a faint plication in the median sinus. Both plications and sinuses are crossed by closely set, imbricating concentric growth-lines, which make the surface quite rough, more so than in T. lepida, which the shell very closely resembles." This species has not received the careful study it requires in order to eluci- date some of its critical features. Sandberger's description and figures are, nevertheless, excellent, and the more important of these have been here intro- duced. The structure of the loop is still unknown. The spirals were coiled * Die Veisteinerungen des rheinischen Schichtensystems in Nassau, pi. xxxiv. fig. 18. 1850-1856. t Zusammenstellung' und Beschreibung- sammtlicher im Uebergangegebii-ge der Eifel vorkommenden Brachioiioden, p. 180, pi. xxiv, fig. 3, a. b. 1853. BRACHIOPODA. 131 obliquely outward, toward the lateral slopes of the pedicle-valve, similar to those of Atrypa, though more divergent. In 1882, Mr. Davidson introduced* the term Bifida as a generic designation for the species above referred to by Schnur as a very close ally of Terebratula venusta, viz.: T. lepida, Goldfuss, as quoted by d'Archiac and de Verneuil,! the Atrypa lepida, Davidson,^ and the Retzia lepida, Kayser, § a form occurring in association with T. venusta in the Devonian of the Eifel, and known also in the middle Devonian of Torquay. Mr. Davidson has shown, from preparations made by the Rev. Mr. Glass, tliat the spiral coil is loosely arranged, the ribbon making but four or five volutions ; the apices of the cones are directed obliquely outward toward the lateral slopes of the pedicle-valve. The loop is described as simple, "like that in Meristina [ Whitfieldella], with the exception that it is placed nearer to the attachments of the hinge- plate, and that, at the point where the two lamellae composing the loop join, there is a short bifur- cation directed upwards" (p. 28). It was this alleged bifurcation of the loop that suggested the fig. m. T, T , 1 1 • r- ,1 • 1 ii i Bifida lepida, Goklluas. name Bifida, and on the basis of this also that ^,^^ b,acuiaium as represented by Mr. Davidson compared and classified the shell Davidson ivom 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 diflferent 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 Brachiopoda, p. 21. t Transactions of the Geological Society of London, second sei'., vol. vi, p. 386. 1840. I British Devonian Brachiopoda, p. 52. 1864. § Zeitschr. der deutschen geolog. GesellschafI, vol. xxiii, p. 559. 187). I From specimens from Gerolsteiu in the Eifel, furnished by Dr. E. Holzapfel, of Aachen. 132 PALAEONTOLOGY 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 Fig. 111. Fio. llfi. Fig. n7. Fio. 118. Fig. 119. Figs. n*-n9. Consecutive transverse sections of Anoplotheca [Bifida) lepida, Goldfuss. (c.) Pig. lU. Section just below apex of pedicle-valve ; sUowing the teeth and the form of the hinge-plate or cardinal process. Fig. 115. Section a little further forward; showing the elevation of the socket walls and the beginning of the median septum in both valves. Fig. 116. Section at anterior edge of hinge-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 tlie 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 llil. Section along the stem of the loop and slightly back of the junction of the lateral branches ; .showing the articniatiou of the stem with the grooved ridge of the upi)er valve, .and the height of the medi.an septum supporting the loop. Figs. 111-118 are from the same specimen ; lig. 119 from another ex- amjile. 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. IJO. Fig. 121. Figs. 120, 121. The brachidium of Anoptotkeca [Bifida) lepida. Fig. 120. A lateral view, showing the relations of the loop to the median septum and ridge. Fig. 121. A posterior view from behind. (c) 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 Soess. 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 AlNOPLOTHECA. 134 PALEONTOLOGY OF NEW YORK. Subgenus CCELOSPIRA, Hall. 186:1 PLATE LIII. 1839. Atrypa, Sowerby. Murchison's Silurian System, p. 637, pi. xx, fig. 7. 1841. Atrypa, Conrad. Geol. Siirv. N. Y.; Ann. Rept. Palaeont. Dept., p. M. 1813. Atrypa, Hall. Geolog-y of N. Y. ; Rept. Fourth Disl., p. 71, fig. 4. 1852. Atrypa, Hall. Paleontology of N. Y., vol. ii, pp. 74, 75, pi. xxiii, figs. 9-11. 1855. Hemithyris, McCoy. British Pal.'eozoic F"ossils, p. 201. 1857. Ltptoccelia, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 107. 1859. LeptocceUa, Hall. Paljeontology of N. Y., vol. iii, p. 24.'5, pi. xxxviii, figs. 1-7. 1863. Ccclospira, Hall. Sixteenth Ann. Rept. N. Y. State Cab. N.it. Hist., p. 60. 186(5. LeptocceUa, Billings. Catalogue of Silurian Fossils of Anticosti, p. 48. 1866. Atrypa, Davidson. British Silurian Brachiopoda, p. 136, pi. xiii, figs. 23-30. 1867. Ccelospira, LeptocceUa, Hall. Palaeontology of N. Y., vol. iv, pp. 328-330 (fig. 1), 365, pi. Hi, tigs. 13-19 ; pi. Ivii, figs. 30-39. 1884. LeptoccBlia, 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 I^eptocalia 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 Terebraiula 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 * Paleontology 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 proces.ses curv- ing gently forward and thence upward, not as in Zygospira, 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. FIG. 123. FIG. 123. Fig. 122. The brachidiiim of Ccelospira concava, Il.ill. Fig. 123. Profile, showing the elevation of the loop. The stem of the loop is probably broken and therefore shorter than is natural. ic.) In front of the base of the loop the primary lamelliB become at once narrow and delicate, and it not infrequently happens, in preparations of the interior. 136 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 Ccelospira 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 Ccelospira 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 plicaiula, 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 LIII. 1841. Atrypa. Conkad. Geol. Survey N. Y. ; Rept. Palsont. Dept., p. 55. 1846. Atri/pa, Morris and Sharpe. Quart. Jour. Geol. Soc, vol. ii, p. 27ti, pi. x, tig. 3. 1856. Orthi/t, Sh.vrpe and Salter. Trans. Geol. Society London, second ser., vol. vii, p. 203. 1857. LeptocaHa, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. History, p. 108. 1859. Leptoadia, Hall. Palseont. of N. Y., vol. iii, pp. 449-452, pi. ciii b, fig-s. 1 a-g ; pi. cvi, figs. 1 a-/. 1861. Orthis, Salter. CJuart. Jour. Geol. Society, vol. xvii, p. 68, pi. iv, fig. 14. 1868. Leptocodia, Meek and Wokthbn. Geol. Surv. Illinois, vol. iii, p. 397, pi. viii, tigs. 3 a-c. 1892. Leptocodia, Ulrich. Pal^ozoische Verstein. aus Bolivien; Neues Jabrb. fiir 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 Calospira 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- BRACHIOPODA. 137 nal septa, it agrees throughout with Anoplotheca and Ccelospira. In the original diagnosis of Leptoc(elia, L. flabellites 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 Leptoc(Elia too widely from Anoplotheca and Ccelospira. There are but two other species which can safely be refen-ed 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.) Leptoccelia 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 has not been reported in the rich lower and middle Devonian faunas of the Amazonas, but occurs at Ponta Gi'ossa, Brazil. Salter identified it as Orthis palmata among some palaeozoic fossils from South Africa, and Ulrich suggests that a similar shell fi'om the Cape, referred to by Murchison* and subsequently by DE VerneuilI as Orihis calladis, is probably this species. Of the three species so intimately associated in the Bolivian Devonian, Leptocoslia jiabellites, VituUna 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 ; Tropidoleptus and Vitulina appearing only with the introduction of the Hamilton fauna. Genus VITULINA, J Hall. 1860. .SUI'l'LEMENTARY PLATE. 1860. VituUna, Hall Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 72, figs. 1, 2; p. 82. 1862. VUidina, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., p. 187. 1867. VituUna, Hall. Paleontology of New Yorli, vol. iv, pp. 409-411, pi. Ixii, tigs. ], a-i. 1874. VituUna, Rathbun. Bull. Buffalo Society of Niitural Sciences, vol. i, p. 255, pU ix. 1876. VituUua, Derby. Bull. Museum Harvard College, vol. iii. No. 12, p. 282. 1881. VituUna, Rathedn. Proc. Boston Society of Natural Histoi-y, vol. xx, p. 36. 1890. VituUna, Derby. Archivos do Museu Nacional do Rio de Janeiro, vol. ix, p. 76. 1891. VituU7ia, Ulrich. Neues Jahrbuch fiir Mineralogie, etc., p. 273. 1892. Vituli7ia, Ulrich. Neues Jahrbuch fiir Mineralogie, etc., Beilageband iii, p. 71, pi. iv, figs. 26-29. The nature of the widely distributed little species VituUna 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. Societ<5 G^ol. France, vol xi, p. 166. 1840. I This name is said by Dall to have been employed by Swainson in 1840 for a genus of Gastropoda, 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 error for Vitularia, 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 vex'y 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 Ccelospira ; and the socket walls, which are also the bases of the crura, are short, but prominent and elevated, bordering deep and narrow * Palseontology of New York, vol. iv, jip. 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 tlie lateral margins of the valves. On the dorsal side the primary lamellas 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 hy 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. ViTULiNA now takes its place quite naturally in close association with C«lo- 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 Tropidoleptus, 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- leptus carinatus wherever Devonian faunas have been recognized, and perhaps more abundantly in the lower Devonian, in association with Leptocalia palmata, Salter, or L.fiabelUtes, 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 (Maecuri'i) and upper (Eren'-) 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 Parand, 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 STf'BEL in the valley of the Rio Sicasica.f The same author has identified this shell in close association with Lepiocalia Jiabellites, 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. Genus 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 Pani, Brazil,"! for a Silurian Fig. 121. nu. 123. Fig. 126. Fig. 127. Figs. 1J4-1'27. Anahaia Paraia, Clarke. Fig. 121. Exterior, showing the br.achial valve. Fig. ri.!. Profile of a somewhat compressed s|pecimen. Fig. 12«. Interior of the brachial valve; showing the cardinal process, crura, dental .-.ockels and septum. Fig. 127. Internal cast of portion of the pedicle-valve; showing the muscular scars. (c.) * Nota sobre a Geologia e Paleontologia de Matto Grosso, pp. 76, 77. 189(1. t Neues Jahrbiioh fiir Mineralogie, etc., Beilageband vii), pp. 71-73, pi. iv, figs. 26-29. 1892. t Archivos do Museu Nacional do Rio de .Janeiro, vol. x 142 PALAEONTOLOGY OF NEW YORK. . shell allied to Leptocalia flabellites 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 Leptocoelia. Genus NUCLEOSPIRA, Hall. 1859. PLATE XLVIII. 1843. Atrypa, Hall. Geology of N. Y.; Rept. Fourth Dist., p. 200, fig. 3. 1852. Ort'his, Hall. Palaeontology of N. Y., vol. ii, p. 250, pi. Hi, tig. 1. 1857. Spirifer, Hall. Tenth Rept. N Y. State Cab. Nat. Hist., p. hi. 1859. Nudeospira, Hall. Twelfth Rept. N. Y. State Cab. Nat. Hist., pj). 24-26. 1859. Nudeospira, Hall. Palaeontology of N. Y,, vol. iii, pj). 219-223, pi. xiv, fig. 1 ; ]il. xxviii, b, figs. 2-19. 1860. Nudeospira, White. Jour. Boston Soc. Nat. Hist., vol. viii, p. 227. 1863. Nudeospira, Hall. Transactions of the Albany Institute, vol. iv, p. 226. 1867. Nudeospira, Hall. Palaeontology of N. Y., vol. iv, pp. 278, 279, pi xlv, tigs. 33-57. 1879. Nudeospira, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p. 160, pi. xxv, tigs. 22-28. 1882. Nudeospira, Hall. Eleventh Rejit. State Geologist of Indiana, p. 301, pi. xxv, tigs. 22-28. 1882. Nudeospira, Whitfield. Annals N. Y. Acad. Sciences, vol. ii, p. 194. 1884. Nudeospira, Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 147. 1889. Nudeospira, Nbttblroth. Kentucky Fossil Shells, pp 103, 104, pi. xxxii, figs. 1-4 ; 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 lamellte. 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 umbonal region and extends to within a very short distance of tlie 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 extremit3\ 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 lamellas. 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 lamellge, 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 papillse which are the bases of the spinules. Type, Spirifera ventricosa, Hall. Lower Helderberg group. Observations. Nucleospira 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 NucLEospiniDjs, viz. : Retzia, Mekistina, Eumetria and Trematospira, but the distinctive features of the brachidium bring it into closer association with Anoplotheca and CcELOSPiRA, notwithstanding the great differences in exterior. The spinul- ous surface, which appears to be common to all the species, is suggestive of Parazyga 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 oi' Anoplotheca, nor is its extremity bifurcated to em- brace the low median septum of the valve. The stem usually makes a large BRACHIOPODA. 145 angle with the lateral branches of the loop, and is deflected posteriorly ; its surface is generally cylindrical, but in Nudeospira concentrica it is considerably flattened. Fig. iw. Fig. 129. Fig. ISO. Fig. 131. Fiff. 12*f. A iireparation of Nudeospira ventricosa. Hall; showing the umbonal blades, the loop and the form of the first volution of the spirals. Figs. 129, 130. The primary lamell.-e and loop of Nudeospira i-eniricosa. Hall. Fig. 131. A preparation of A'ucZeos^fra ct»?icinrta, Hall; showing one-hall of the hi-achitlium, the mode of attach- ment of the crura to the umbonal blades and the flattened stem of the loop- (0.) The structure of the hinge-plate and brachial apparatus is now known in the following species of this genus : N. pisuni, 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. concentrica 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 Nudeospira 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 lamellse, but may possibly indicate a pathological or excresential condition. Fig. 13.'. Loop of Nucleoxpira, sp. ?, from the Cornilerous limestone at the Falls of the Ohio. (c ) Genus CYCLOSPIRA, gen. nov. PLATE LV. 1842. Orthis, Emmons. Geology of New York; Rejjt. Second Dist., p. 395, fig. 4. 1847. Atrypa, Hall. Palseontulogy of New York, vol. i, p. 139, pi. xxxiii, figs. 3 a-e. This proposed division is founded on the species, Orthis bisulcata, 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. Fio. 133. Fig. 134. Front and proflle views of Cyclospira bisulcata, 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 lamellae. 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 ZvGOSPiRA-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 Fig. 135. Fig. 136. The biachiiiiam'of Cyclospira 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 spirigerous shell actually ajugate. Subsequent investigations of the brachidium nmst 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- PiRA, Catazyga and Glassia, in which the spirals are also introverted, and * Specimens of Airypa bisulcata 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 has broken 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 as possessed 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,j: 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 Fig. 137. Fig. 138. The brachidium of Atrypa I.Protozijgci'i exigua. Hall. (n.) 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 off, 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 * Catalogues of the Silurian Fossils of the Island of Anticosti, p. 47. 1866. t British Silurian Brachiojioda, Suiipl., p. 121. 1862. I PalsBontology of New York, vol. i, p. 141, pi. xxxiii, fig's. 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. Sakdeson has described it as a new species,* under the name Zr/gospira? aquila from the Trenton limestone at Minneapolis and other local- ities in Minnesota. Winchell and Schuchert have included it in a supposed primitive impunctate terebratuloid genus, Hallina, and have termed it Hallina Nicollett.^ 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 Schuchert 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 * Bull. Minnesota Academy of Natural Sciences, vol. iii, No. 3, p. 335, pi. Iv, tig's. 15-18. 1892. t American Geologist, vol. ix, p. 292. 1892. Geological Survey of Minnesota, vol. iii, pp. 471, 474, pL xxxiv, tigs. 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. 139. ria. UO. Fig. 141. Preparations showing the structure of the brachidium in Hallina Saffordi, Winchcll and Schuclicrt. Fig. 139. The peilicle-valve cut so as to show the tips of the ascending lamellae. Fig. 140. The opposite side, showing Uie form of the primarj' lamellae as far as the base of the loop, and the char- acter of the latter. Fig, 141. View showing the form of the brachidium 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 Atnjpa exigiia 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 Zygospira, 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 Airypa exigua the term Protozyga 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 * Hallina Saffoi-di has a simple hing-e-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 Airypa Usulc.ata had been demonstrated and described in manuscript under the name Cyclospira, some time before the treatise on the Silurian Brachiopoda of Minnesota, by Winchell and ScnucHERT (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 Cyclospira was there used with our knowledge and consent. ' 152 PALAEONTOLOGY OF NEW YORK. Genus GLASSIA, Davidson. 1881. 1849. Atryjja, SoyiKHBY. Silurian System, pi. viii, fig. 9. 1859. AtJiyris? Salter. Siluria, second ed., p. 542, pi. xxii, fig. 16. 1867. Athyris, Davidson. British Silurian Brachiopoda, p. 121, pi. xii, fig. 19 ; pi. xiii, figs. 5, a. 18S1. Olassia, Davidson. Geological Magazine, new sei-ies, vol. viii. 1882. Olassia, Davidson. British Devonian and Silurian Brachiopoda Supplement, p. 38, pi. i, figp. 10-14; pp. 116-120, pi. vii, tigs. 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 Ndcleospira. Muscular impression consisting of two widely divergent, oval diductor scars, between which lies a broad ad- ductor scar. Fig. U2. Fig. 143. Figs. H2-144. Glassia obovata, Sowerby. Fig. U2. Interior 01' the petiicle-valve. Fisrs. U3, 144. Views of the exterior. Natural size. FIG. 114. (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 Fig. 145. lirachidiuni of Glassia oborata, 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. Rominger 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. Genus ZYGOSPIRA, Hall. 1862. PLATE LV. 1847. Atrypa. OrtUs ?, Slmocisma, Hall. Paleontology of N.Y., vol. i, vp. 140-142, 288, pi. xv, fig. 15 ; pL xxxiii, figs. 4, 5 ; pi. Ixxix, fig. 5. 1859. RhyncJionellah Hall. Twelfth Kept. N. Y. State Cab. Nat. Hist., p. 66. 1860. Atrypa, Hall. Thirteenth Kept. N. Y. State Cab. Nat. Hist., p. 69. 1862. Zygospira, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., p. 154, figs. 1, 2. 1862. Zygospira, Billings. Canadian Naturalist and Geologist, vol. vii, p. 393. 1862. Athyris, Billings. Palieozoic Fossils, vol. i, p. 147, tigs. 125-127. 1S63. Athyris, RhyncfKmella ?, Billings. Geology of Canada, p. 168, fig. I.'>2; p. 211, fig. 211 ; p. 212, fig.s. 214-216. 1864. Sfenocixma, Meek and Haydbn. Paleontology of the Upper Missouri, p. 16. 1866. RhynchoneUa, Zygospira, Billings. Catalogue Silurian Fossils of Anticosti, pp. 44, 46. 1867. Zygospira, Hall. Twentieth Rept. N. Y. State Cab. Nat. Hist., p. 267. 1868. Zygospira, Mekk. 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, Meek. Paleontology of Ohio, vol. i, pp. 125, 126, pi. xi, figs. 4, 5. 1875. Zygospira. Millkk. Cincinnati Quarterly Journal of Science, vol. ii, pp. 58, 59. 1878. Zygospira, U. P. Jambs. The Palfeontologist, No. i, p. 7. 1879. Zygospira, Uliuch. Journal Cincinnati Soc. Nat. Hist., vol. ii, p. 14, pi. vii, fig. 10. 1882. Zygospira, Hall. Eleventh Rept. State Geologist of Indiana, j). 305, pi. xxvii, fig. 7. 1882. Zygospira, Anazyga, Davidson. British Silurian Brachiopoda, Supplement, pp. 122, 128. 1883. Zygospira, Hall. Transactions of the Alb.iny Institute, vol. x, p. 70. 1889. Zygospira, Nettblroth. Kentucky Fossil Shells, p. 138, pi. xxxiv, figs. 21-25. 1893. Zygospira, Winchell and Schcchekt. 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. BRACHIOPODA. 155 The crura are short and straight at their imion 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 Zygospira, erected on the basis of these characters. Fig. 146. FIG. 147. Fig. lU. FIG. 149. Piep.arations of Zygospiramodesta, (Say) Hall; showing the variation in position of tlie loop. (C.) 156 PALEONTOLOGY OF NEW YORK. A most remarkable feature of this genus is the variability in the position of the looi5. This is not a specific character, but a matter of variation among individuals of a given species. For example, in the type-species, Z. modesta, the loop may be found in any of the four positions represented in the accom- panying figures, which have been made from actual preparations. The same peculiarity is shown in Z. Cincinnatiensis, Meek, Z Kentuckiensis, James, and Z. recurvirostra, Hall. It is, nevertheless, true that, of a given number of individuals, say of Z. modesta, the larger fraction will have the loop near the posterior limb of the primary lamelliB ; at the same time, examples thoroughly typical in all other respects, will have this organ placed as far forward as it ever occurs in the species Z. recurvirostra, while in the latter species the larger percentage of a given number of individuals will have the loop anterior, and a few have it situated medially. These two species, Z. modesta and Z. recurvirostra, represent the extreme possibilities of variation in this respect, and while it may be said that the normal position of the loop in the former is posterior, and in the latter anterior, yet the variations of the one anteriorly, pass the limit reached by the variation of the other posteriorly. This mobility in the loop of Zygospira is without parallel among other genera, and it has led to some erroneous observa- tions and determinations, based upon insufficient data.* The term Anazyga, therefore, which was proposed by Davidson in 1882f for the species Atrypa recurvirostra, Hall, on the basis of its anterior and recurved loop, must be rejected. In the illustration which this author has given, the position of the loop is, perhaps, more extremely anterior than in any of the numerous preparations we have studied, but there can be no question that characteristic examples of the species have a condition of the brachial apparatus which is indistinguishable from that of Z. modesta. Zygospira has a very considerable representation in species. It seems to have made its appearance in the fauna of the Trenton limestone, in Producta * Reference is made to the observations and criticisms by Dr. Davidson in the Supplement to the British Silurian Brachiopoda (p. 122), upon the orig-inal determination and illustrations of the position of the loop in Z. modesta. The latter are correct, though they may not represent the extreme posterior position assumed at times by the loop of^this species.]) t Op. cit., p. 128., BRACHIOPODA. 157 modesta, (Say) Hall, Atrypa recurvirostra* and A. dejleda, Hall. In the Hudson River group are the species Z. modesta, (Say) Hall, Z. Kentuckiensis, James, Z. Cindnnatiensis, Meek, Z. concentrica, Ulrich, Z. pau- pcra, Billings, and probably the Rhynchonella mica, Billings. There is still another species in this fauna as it is developed in Pike county, Missouri, Zygospira putilla, sp. nov. (see Plate LV, figs. 35-37), which possesses an unusually elongate form, but retains the coarsely plicate surface of Z. modesta ; its loop appears to be persistently posterior in its posi- tion. ,10 i>. T r> pi.ii ±^ ' 1*1 Preparation showing tlie brachidium In faunas 01 later date occurs the species which or zygosptra putaia. (c) has been described as Z. minima, Hall, in the Niagara group at Waldron, Indiana, but it is exceedingly rare, and its internal structure is not known. The genus has not been satisfactorily identified in European faunas. Subgenus CATAZYGA, s.-gen. nov. PLATE LVI. Mr. E. Billings described,! in 1862, the species Athyris Headi, from the Hud- son River formation on the " south shore of the St. Lawrence, opposite Three Rivers." It is a rather large, subcircular or ovoid shell, with valves more con- vex than in Zygospira, the rotundity of the pedicle-valve obscuring the usual prominence of the umbo in that genus. Both valves bear a low median sinus, while the external surface, instead of being coarsely plicated as in Zygospira, is covered with a great number of fine radiating striae. The typical external expres- sion of Zygospira is thus to a large degree lost. On the interior of the pedicle- valve the muscular impressions are well defined and similar to those seen on the internal casts of the Orthis? or Zygospira erratica, from the sandy Hudson River * Messrs. Winchell and Schuchert have recently separated fi'om the shells usually _i-eferred to this species certain lai-ger and more finely striated shells from the Trenton and Galena horizons. These are \.nYmeCL Zygospira Uphami. See American Geologist, vol. ix, p. 291 (1892), and Geological Survey of Min- nesota, vol. iii, p. 468. pi. xxxiv, figs. 45-48 (1893). By the favor of Prof. N. H. Wincuell we have been permitted to refer to advanced pages of the latter work. + PaliEozoic Fossils, vol. 1, p. 147, fig. 125. 158 PALEONTOLOGY OF NEW YORK. (Lorraine) shales of central New York, that is, the pedicle-cavity is deep, and in front of it lies a more deeply excavated, short, sharply defined and longitudinally striated impression. In the brachial valve is a broad anterior and a narrow, elon- gate posterior pair of scars. The spirals are of essentially the same character as in Z. modesta, though the form of the cones is such that their apices converge toward the median line in a plane just below the surface of the brachial valve. The loop, however, differs ; in the first place, it is persistently posterior in its position, originating as in Atbypa, the lateral lamellae bending downward toward the bottom of the brachial valve and directed forward in lines which are parallel for a ^ Fig. 151. short distance. Thence they bend inward and P'-epanaion of catey^^a ffe«d.;, Bniings; -' showing the form ol the fpiral cones upward, meeting in a sharp angle in the space just ^"fj""''' •"' "'""' ''""' '"" '';•','""" behind the apices of the spirals. These external and internal peculiarities afford a sufficient basis for the sep- aration of shells of this type from Z. modesta and its allies. Mr. Billings de- scribed two varieties of A. Headi, viz., A. borealis, from Lake St. John and the Saguenay River ; and A. Anticostiensis, from Anticosti, both from the Hudson River formation. The former " differs from the typical form in being more elongate- oval and in having a more tumid umbo" (op. cit., p. 147). This elongate variety prevails in the Hudson River fauna of Ohio, though in association with shells agreeing with the typical A. Headi. The variety Anticostiensis retains more of the contour of a Zygospira, the pedicle-valve being more prominently keeled, the convexity more unequal, and, furthermore, there is a broad sinus on the brachial valve, while there is no trace of one on the other valve. This fossil is like Z. erratica, both in contour and in the fine striation of the exterior. If there is a specific difference in the two forms it is extremely slight, too slight, indeed, with our present knowledge, to indicate either in words or illustration. These forms are interesting as being intermediary between the typical Zygospira and the representatives of the proposed subgenus Catazyga.* * Our specimens of 4(Aj/>'is fieadj and its variety j4. Anticostiensis &ve (vom the original localities, and from the investigation of these we are compelled to disagree with Mr. Davidson's determinations given upon pages 126-128 of his Supplement to the British Brachiopoda. On page 127 he states that BRACHIOPODA. 159 It ought, perhaps, to be observed that in a postscript note circuhited with some copies of the Twelfth Report on the New York State Museum of Natural History, the name Orthonom^a 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 Zygospira and the biconvex Catazyga, this term would be entitled to consideration. Genus CLINTONELLA. gen. nov. PLATE Lll. 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 lamellaB which terminate abruptly. The lower and inner mar- gins of these lamellse are thickened, contracting the pedicle cavity, which is, consequently, narrow and deep. The diductor scars are of moderate size, tiabellate in outline and deeply impressed at their posterior extremity. They Anticostiensis and horealis "are only variations in shape of the same species, but specifically distinct from the Zygospira (Athyris ?) Headi of Billings." Further, in indicatinarture of a variety from the specific type. The time-value of variations from the species has been expressed by Waagen, who proposed to restrict the teim variety to oscillations of the type contemiioraneous with tlie type itself, and applied the term mutation to variations appearing after the extinction of the type. 168 PALEONTOLOGY OF NEW YORK. stones, the shells show the fact that the squamae of earlier growth, or those upon the urabonal and median surfaces of the valves, have been worn oft' 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 surfiice-markings which can be considered as more than variations of expression depending upon the surrounding physical conditions or similar influences. 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 lamellse 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 Brachiojioda, pi. xiv, tigs. 1, 2. Barrande, Systeme Silui-ien, vol. v, pi. xix, fig. 7. Whiteaves, Contrib. to Canadian Palaeontology, vol. i, pi. xxxvii, fig. 8. f It is hardly necessary, were it possible, to determine with precision which of the many expressions of Atnjpa re.ticidaris 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 Oriskany 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, Atnjpa 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. elUpsoidea, Nettelroth) ; these are locally found in great numbers, indicating a gregarious habit ; {h) 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 Univei-sity, vol. iii, p. 98, pi. lii, fig-. 11, 1887 ; vol. iv, pi. ix, fig. 7, 1888 The expression of this Waverly shell, juiiging- from the figures cited, is more that of the medium sized individuals of the Hamilton group than of the large forms of the later Devonian. 170 PALAEONTOLOGY 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 Atrijpa reticularis, is unequaled by any other organism except that of the brachiopod Leptana rhom- boidalis, Wilckens, and it far outranks that species in geographic distribution and prolific individual development. Almost coincident in time with the appearance of Atri/pa 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 lamellae. 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 mucli larger size and very gibbous form, the concentric lamellae being distant and strongly developed. This is the shell known as Atnjpa aspera, Schlotheim. At this horizon the form mentioned is intimately associated with the typical, inore 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 Atrijpa 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 exteiior of this fossil suggests its relation to the still smaller, coarsely plicated shells which have been placed under the genus Atrtpina (A. dispwilis. Niagar.i group ; A. hnbHcata, Lowei' Helder- berg group). In the structure of its bi-achidium and the direction of the spiral cones, A. rugosa is a true Atrtpa, 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 Atrijpa reticularis, occurring in the Niagara fauna at Waldron, Indiana, the free concentric lamellte 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 de Vebnbdil. Geologie de la Russie, etc., p. 93, pi. xi, tig-. 13. 1845. ScHNDR. PalsEoiitographica, vol. ili, p. 181, pi. xxiv, fig. 4. 1854. Kayskr. Abhanill. fJeol. Specialkarte von Pi'euss. u. den Thiir. Staat., pp. 184, ISfi, pi. xxviii, figs. 4-6. 1878. TscHERNYSCHKW. 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, Hall, of 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 in 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 them. 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 nodostriafa 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 bi'oad, 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 Paloeontology of New York. The peculiar structure of the loop as a pair of separate pro- cesses, was first accurately figured by Quenstedt,J and afterwards described and illustrated by Mr. William Gurley. § 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 Atrypa, and the more elementary condition of * Davidson has shown that the spii-al ribbon in this form is fimbriated, and this character wp also find well preserved in natni-al preparations of the spirals of A. reticularis 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-S. 1S07. I Petrefactenkunde Deutschlands, Brachiopoden, pi. xlii, figs. 87o, 9U. 1871. § Proceedings American Philosophical Society, vol. xvii, p. 337, pi. xiv. 1S78. 1 British Silui-ian 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 tlie 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 durin"- 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 Lll. This name has been proposed* for the species Terebratula latilinguis, Schnur,f originally described from the middle Devonian at Gerolstein. This species was Fig. 154. no. 165. ^inraU oY GruenewaldtialatiHnguU,^c\u\m\ In lig. 155, the pedicle valve is the lower ami llie two mediuii dots represent sections of llie primary lamella;. (Tscheenyschew.) considered by Kayser as a variety of Atri/pa reticular is. '^ 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 Tschernyschew, the spiral cones have their bases lying against * Die Fauna iles Untei en Devon am West-alihan^e lies Urals, jip. 46, 89, pi. vi, figs. 75-77. t Ziisanimenstellung' and Beschreibung ssammtlicher im Ueberg'ung.egebirge iler Eifel vorkoramenden Bi'achiopoden, p. 183, pi. xxv, fig 1, 1853. I Zeitschr. 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 LI I. 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 Atrypa, 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 Wesf-abhange des Urals, pp. 48, 90, pi. vii, tigs. 80, 86. BRACHIOPODA. 177 Genus RHYNC HON ELLA, Fischer de Waldhrim. 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 teatures 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 than 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. Rhynchonella, Fischer de 'Waldheim. Notice des Fossiles du Gmiv. 9, 1859. Rhynchonella, Hall. Palaeontology of New Yoi-k, vol. iii, p. 23t), jil. xxxv, figs, tin-.i/- 1867. i^tenocisma, Hall. Palaeontology of New York, vol. iv, pp. 334, 335. Mr. Conrad, 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 Terehratula Schlotheimii, Von Buch." The T. Schlolheimi 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 tlie term Stenoschisma (Stenoscisma as written by Conrad) in accordance with the characters of von Buch's species, which renders it equivalent to King'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 ;is 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 Palaeontology 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 PALjEONTOLOGY OF NEW YORK. and we should feel justified in assuming Rhynchmella formosa to be the type of the genus rather than to reject the well-established term Camarophoria and substitute Stenoschisma for it. Upon reviewing the Devonian shells which were referred to Stenoschisma in Volume IV of the Palteontology 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 Camarophoria 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 lamella3 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 differences 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 jR. 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 unconiinon throughout the Devonian rhynchonellids. Genus CAMAR0T(ECH1A, nom. nov. • PLATE LVII. 1841. Atrypa, Conrad. Ann. Rept. PaL-eont. Dept. N. Y., p. .55. 1843. Atrypa, Hall. Geology of New York ; Rept. Fourth Dist. ; Tables of Organic Remains, No. 6(j, figs. 3, 4 ; No. U7, fig. 2. 1847. Atrypa, Hall. Palaeontology of New York, vol. i, pp. iil, 23, pi. iv (liis), figs. 7, 9. 1852. Atrypa, Hall. Paleontology of New York, vol. ii, p. 70, pi. xxiii, figs. 4, 5 ; p. 274, i)I. Ivii, fig. 1 ; p. 279, pi. Iviii, figs. 3, 4. 1857. Rhynchonella, Hall. Tenth Ann. Kept. N. Y. State Cab. Nat. Hist., p. 78, figs. 1-7 ; p. 82, figs. 1-3 ; pp. 81, 86. 1860. Rhynchonella, Billings. Canadian Journal, vol. v, pp. 271, 272. 1860. RliyndioneUa, Hall. Thirteenth Ann. Rept. N. Y. State Cab. Nat Hist., pp. 87, 88. 1862. Rhynchonella, A. Winchell. Proc. Acad. Nat. Sci. Philadelphia, pp. 407, 408. 1862. RhyiicJwTiella, BihUUGS. Pala'ozoic Fossils, vol. i, pp. 141-143, figs 118-120. ]S63. Rhynchonella, Hall. Transactions of the Albany Institute, vol. iv, ]>p. 215, 216. 1867. Rhynchonella {Stenvcisina), Hall. Palojontology of New York, vol. iv, pp. 335-345, 348-353, pi. liv, figs. 1-59 ; pi. liv a, figs. 1-23, 44-49 ; jil. Iv, figs. 1-52. 1879. Rhynchonella, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., pp. 163, 164, pi. xxvi, figs. 12-33. 1882. Rhynchonella, Hall. Eleventh Ann. Rept. State Geologist of Indiana, pj). 305-307, pi. xxvi, figs. 12-33. 1884. Rhynchmiella, Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 152, pi. xiv, fig. 3; j)l. xv, fig. 6 ; p. 155, pi. xiv, fig. 8. 1887. Rhynchonella, Gosselbt. Annates de la Soci6le Geologique du Nord, vol. xiv, p. 188, l>ls. i-iii. 1888. Rhynchonella, Herhick. Bulletin Labor. Denison University, vol. iii, pp. 39, 40, \A. v, fig. 1 ; pi. vii, fig. 25 ; pi. x, fig. 9. By restricting the application of the term Stenoschisma to shells agreeing in hinge-structure with Rhynchonella formosa, the necessity is created for ;i 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, * Paleontology of New York, vol. iv. 190 PALEONTOLOGY 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. obtusiplicata, Hall, of the Niagara group, and it may prove that R. Indianensis, R. negleda, 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 serial transverse sections of the shells ; since no separated valves or satis- factory internal casts of these species have been obtainable. BRACHIOPODA. 191 yielded somewhat to the robust forms possessing a cardinal process, which are referred to the genus Uncinulus. 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 Camarokkchia 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 Rhynchotre.ma. 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 Camarotcechia 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 Ilelderberg, Hamilton and Chemung faunas, few will 192 PALEONTOLOGY OF NEW YORK. be found which present any material variation from the type of Camarotuochia. Therefore, with our present Itnowledge, all the species definitely referred to Stenoschisma in Volume IV of the Palaeontology 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. * According to the identifications by Prof. C. L. Herrick, Bull. Laboratories Denison University, vol. iii, pp. 39, 40. 1888. BRACHTOPODA. 193 LIORHYNCHUS, Hall. 1860. PLATE LIX. 1842. 0)-ms, AtryjM, Vanuxem. Geology of N. Y. ; Rept. Third Dist., p. 14fi, fig. S; p. 168, tig. 2; p. 182, fig. 2. 1843. Atrypa, Hall. Geology of N. Y. ; Rept. Fourth Diwt., j). 182, tig. 11 ; p. 223, fig. 2, Tiiblea of Organic Remains, No. 67, fig. 1. 1855. Rhyncliondla, Shomakd. Rept. Geol. Surv. Missouri, p. 205. 1860. Leiorhynchus, Hall. Thirteenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 75, 85, 80, figa. la, 6. 1860. Mliynckonellaf Billings. Canadian Journal, vol. v, p. 273, figs. 26-28. 1863. Rhynchonella? Billings. Geology of Canada, p. 384, fig.s. 418a-c. 1866. Leiorhynchus. A. Winchell. Rept. Lower Peninsula of Michigan, p. 95. 1867. Leiorhynchus, Hall. Palseontology of N. Y., vol. iv, pp. 855-364, pi. Ivi, figs. 1-49 ; pi. Ivii, figs. 1-29. 1868. Rhynchonella, Meek. Trans. Chicago Acad. Sci., vol. i, p. 93, pi. xiii, figs. 9a-c. 1873. Leiorhynchus, Hall and Wiutfield. Twenty-third Ann. Rept. N. Y. State Cab. Nat. Hist., p. 240, pi. xi, figs. 25-27. 1874. Leiorhynchus, Nicholson. Geological Magazine, new ser., vol. i, p. 120. 1884. Rhynchonella, Leiorhynchus, Walcott. Monogr. U. S. Geolog. Survey, vol. viii, p. 153, pi. xv, figs. 1-4 ; pp. 157-159, pi. xix, figs. 5, 9. 1885. Leiorhynchus, Clarke. Bull. U. S. Geolog. Sui'v., No. 16, pp. 24, 31, 33, OS, pi. iii, tig. 14. 1886. Rhynchonella, Ulkich. Contributions to American Palseontology, p. 26. 1887. Liorhynclms, ffiHLERT. Fischer's 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 fsiunas. 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 Leiokhynchlls ; 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 Agassiz), 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 groups so remotely connected. 194 PALEONTOLOGY OF NEW YORK. the Liorhynchus Umitaris, Vanuxem, frequently constitute entire strata of some inches in thiclcness; and also, in the more bituminous layers of the Hamilton group proper, L. muUicostus, Hall, and at times, L. quadricoslatus, 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 ai'enaceous 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 calcareous 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 formatiou of Keokuiv 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 moi-e oblate forms of this species seem indistinguishable from L. muHicosLus, Hall, but L. Laura noi-mally has an elongale-oval outline which is not possessed by typical examples of the former. t Before us is a specimen of the Rhynchonella castaiita. Meek, fi-om the Eureka District of Nevada, agreeing with Mr Walcott's identification of this species as described in volume viii, Monographs of the U. S. Geological Survey, p. 153. This specimen demonstrates a very close specitic similarity to Liorliynchns givhulifonnis, Vanuxem, and serves to fix its geneiic relations beyond doubt. (1) 1828. (I) 1834. (4) 1834. (1) 1839. (4) 1840. BRACHIOPODA. 195 Genera (l)WILSONIA (Quenstedt), Kayser, 1871; (2)UNCINULUS, Bayle, 1878; (3) U N C IN U L I N A, Bayle, 1878; (4) HYPOTHY- RIS (McCoy), King, 1850. PLATES LVIII, LX. (1)* 1S1«. Terehratida, J. Sowerbt. Mineral Conchology, vol. ii, p. 38, pi. cxviii, fig. 'J. (1) 1821. Anomiles, Wahle.vberg. Nova Acta Reg. Soc. Upsal, p. 67. Terebratula, Dalman. Kongl. Vetenskaps. Akad. Handling., p. 139, pi. iv, fig. 1. Tenbtatula, von Buch. Ueber Terebrateln, p. 47. Terebratnla, vo.v Buch. Ueber Terebi-atein, p. 68, pi. xi, figs. 29, a, b. Terebrattda, J. ub C. Sowerby. Silui-ian System, p. 615, pi. v, fig. 21 ; \i\. vi, fig. 7. Atrypa, J. de C. Sowerby. Trans. Geol. Soc. London, 2nd ser., vol. v, ))1. Ivi, fig. 24 ; pi. Ivii, figs. 5, 6. (4) 1841. Atrypa, Phillips. Palaeoz. Foss. Cornwall, Devon and West Somerset, p. 84, pi. xxxiv, fig. 150. Atrypa, Vandxbm. Geology of N. Y. ; Rept. Tiiird Dist., p. 163, tig. 1. Atrypa, Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 215, fig. 1. Terebi-atula, F. Roemer. Verstein. rhein. Uebergangsgeb., p. 65. Terebratula, ue Ver.nedil. Geol. de la Russ. et des Mont, de I'Oural, p. 87, pi. x, fig. 8. Hypothyris, King. Annals and Magazine of Natural History, vol. xviii, p. 28. Atrypa, McCoy. Synopsis Silurian Fossils of Ireland, p. 42. Hypothyris, Phillips and Salter. Mem. Geol. Surv. Great Britain, vol. ii, pt. 1, p. 282. Hemithyris, d'Orbigjiy. Prodrome de Paleontologie, p. 92. Hypothyris, King. Permian Fossils of England, p. 111. Rhynchonella, Davidson. Annals and Magazine of Natui-al History, 2nd ser., vol. Ix, pi. xiii. Rhynchonella, The Sandbergbrs. Verstein. des rhein. Schicht. Syst. Nassau, p. 43, pi. xxxiii, fig. 12. (4) 1853. Rhynchonella, Schncr. Beschr. der Eifel. Brach., p. 185, pi. xxv, fig. 5; p. 187, pi. xxvi, fig. 3 ; p. 239, pi. xlv, fig. 4. (2) 1857. Rhynchmella, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 66, figs. 1-7 ; p. 68, figs. 1-3. (1) 1858. Rhynchonella, F. Schmidt. Archiv fiir- Naturk. Liv., Esth., und Kni-lands, vol. ii. p. 210. (2) 1859. Rhynchonella, Hall. Paleontology of New Y'ork, 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. Rhynchonella, Hall. Canadian Naturalist and Geologist, vol. v. No. 2, p. 146. Rhynchonella, Davidso.n. Bri). Silurian Brachiopoda, pp. 167-173, j)l. xxiii, figs. 1-14. Rhynchonella, Hall. Palseontology of New York, vol. iv, p. 346, pi. livo, figs. 24-43. RhyuvhoneUa, Davidson. Brit. Silurian Brachiopoda, p. 166, pi. xxi, figs. 1-6, 28. Rhynchonella, de Verneuil. Tchihatcheff"s Asie Mineure, Paleontologie, pp. 9, 468. Terebratula, Quenstedt. Petrefactenk. Deulsch.; Brachiopoden, j). 193, pi. xlii, figs. 19^8. Terebratula, Quenstedt. Petrefactenk. Deulsch.; Brachiopoden, pi. xlii, tigs. 15-18. Rhynchonella, Kayser. Zeit.schr. der deutsch. geolog. Gesellsch., vol. xxiii, p. 502. Rhynchonella, Kayser. Zeitschi-. der deutsch. geolog. Gesellsch., vol. xxiii, pp. 507-515, jil. ix, figs. 3, 4. (4) 1877. Rhynchonella, Hall and Whitfield. Geolog. Expl. Fortieth Parallel, vol. iv, p. 247, pi. iii, tigs. 4-8. •The citations .ire numbered to conuspond with Uie generic titles. (4) 1842. (4) 1843. (4) 1844. (1) 1845. (4) 1846. (1) 1846. (1) 1848. (2) 1850. (4) 1850. (1) 1852. (4) 1852. (2) 1860. (1) 1860. (1) 1867. (4) 1867. (2) 1867. (2) 1869. (1) 1871. (4) 1871. (1) 1871. (4) 1871. (2) 1878. (3) 1878. (4) 1878. (2) 1879. (2) 1883. 0) 1883. (2) 1884. 196 PALAEONTOLOGY OF NEW YORK. Unci7udu.k\-wiioti. British Carbon. Bra<:hioiKiiia, pp. 93-10."), pi. xx, fifrs. 1-IH; pi. xxi, figs. 1-20 ; pi. xxii, tigs. 1-1 T) ; |)1. xxiii, \\g». 1-22. 1860. Rhynchonella, McChesney. Ti-an.s. Chicagd Acad. Sci., vol. i, pp. 49, 60. 1802. RhynchontUa, Whitk. Pi-oc. Boston Son. Nat. Hist., vol. ix, p. 2.3. 1865. Rliynchunella, Davidsd.v. Biitish Devon. Bi-achiopoiia, pp. 62, 6:5, pi. xii, tigs. 12 14 ; pi. xiii, tigs. 6-18. 1866. RhynchoTieUa, Meek. Geological Survey Illinois, vol. ii, p. 1.13, pi. xiv, tigs. 4a, b. 1S68. Rhynchonella, Mekk. Geological Survey Illinois, vol. iii, [). 4r)0, pi xiv, tigs. la-d. 1871. TerehraUda, Quenstedt. Petrefactenk. Deutscljlands; Br-ac.hiopoiien, p. 190, pi. xlii, figs. .")-7. 1883. Rhynchmtella, Willi.\ms. American Journal of Science, vol. xxv, p. 91. 1884. Rhynvhimella, Walcott. Monogr. U. S. fieol. Siirv., vol. viii, p. ir)5, pi. xiv, figs. 7, 7a. 1885. Rhynchonella. Clarke. Bull. U. 8. Geo!. Surv., No. 16, p. — . 1887. Rhynvhonella, de Koninck. Faune du Calcaire Carbonifere ile la Belgiipie, 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 Buck's term Pugnacecc, which was tipplied to a division of the Rhynchonellas, embracing the typical forms of this sub-genus. This combination of characters appeared in the middle or later Devoniau 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; R. alta, Calvin, from 204 PALEONTOLOGY OF NEW YORK. the Upper Devonian of Iowa ;* R. Missouriensis, Shuniard, and R. striato-costata. Meek and Worthen, of the Choteau limestone ; R. explaiiata, McChesney, of the Chester limestone ; R. mutata. Hall, R. Ottumwa, White, of the St. Louis group ; R. Uta, Marcou, R. Eatoniiformis, McChesney, and the Camarophoria Swalloviana, Shumard, of the Upper Carboniferous limestone. Shells of this type of exterior abound in all later palaeozoic faunas. Genus EAT ONI A, Hall. 1857. PLATE LXI. 1841. Atrypa, Conkad. Ann. Rept. Palffiont. Dept. N. Y. Geol. Survey., p. 56. 1S42. Atrypa, Vanuxem. Geology of N. Y. ; Rept. Thinl Dist., pp. 120, 121, tigs. 4. 5. 1S4B. Atrypa, M.vniEit. Geology of N. Y. ; Rept. Fir.st Dist., p. 842, fig. 3 ; p. 343, tig.s. 3, 4. 1843. Atrypa. Hall. Geology of N. Y. ; Rejit. Fourth Dist., )). 148, tig. 3. 1857. Eatonia, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 90-92, figs. 1-7. 1859. Eatonia, Hall. Twelfth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 35-37, figs. 1-7. 1859. Eatonia, Hall. PaK-Eontology of N. Y., vol. iii, pp. 241-243, 432-438, pi. xxxvii, figs. 1 a-y, 2 a-c; pi. xxxviii, figs. 14-26; pi. ci, figs. 1, 2; pi. ci a, figs. 2-6. 1868. Eatonia, Meek and Woethen. 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 Rhynvhonella alta, Calvin, which some American writers have considered equivalent to R, pug- nus, Martin, is a local form retaining quite pertistently the features of li. anisodonta, Phillips {R. pugniis, var. anhodonta, Davidson). Though always smaller than the representatives of R. pugiius, occurring in the High Point (New York) fauna, at the base of the Chemung series, it less frequently shows a tendency toward the acute acnminataAWe: fold than the latter. The fact that the New York shell evinces gradations in form which include both the pugmut and the axyiLminata type of exterior is but a further substantiation of the ai'gument 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 passing under these two names. That it may be convenient to retain both terms is undoubtedly true, but the passage of one sei-ies of forms 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 are entitled to these names ; whether, for instance, it would not be better to retain Phillip's name, R. anisodonta, for the former, and, possibly, R. triangularis, Sowerby, for the latter. In both of the former cases the originals were from the Caiboniferous limestone of Derbyshire and attained, as a usual habit, a much greater size than the Devonian shells. The American Carboniferous shells representing the specific type o( U. pugnus, namely, R. striato-costata. Meek and Worthen, R. Missouriensis, Shumard, bear a tine radiate-lineate ornamentation, and what might be interpreted as a similar character is apparent in many of Davidso.\'s figures of the Carboniferous species (Carboniferous Brachiopoda, pi. 22), though this feature is not mentioned in his descriptions. The same character is highly developed in the Devonian species, R. Meyendorfi, de Verne uil, a sharply acuminate shell without plications. BRACHIOPODA. 205 of the valve, all traces of supporting lamellae being absent. Muscular area large, fiabellate and deeply excavated in the substance of the shell. Pedicle impression broad, traversed medially by a longitudinal groove ; diductors ex- tending for about one-half the length of the shell, their outer margins being elevated ; they enclose a pair of small central adductor scars whose posterior margins are raised into prominent myophores. The scars are divided by a slight median septum which is continued posteriorly ; this septum being often rendered very conspicuous by the growth of the shell about the apophyses of the cardinal process of the opposite valve, and in extreme cases its develop- ment is such that it rises above, and encloses the adductor scars, the latter beinf excavated in its substance. In the brachial valve the dental sockets are long and narrow, the cardinal process very large and composed of a stout, erect stem resting upon a rather short median septum, and divided at its summit into two long, divergent, tooth-like branches, whose upper faces extend to the interior surface of the opposite valve ; hence their greatest elevation is at their anterior extremities, whence they slope toward the beak of the valve, usually uniting before that point is reached. The surface of attachment of each of these apophyses is medially grooved. Below them, and at the base of the central stem, arise the crura, which are long, straight and slender, with expanded extremities. The muscular scars are clearly defined and consist of a pair of small posterior adductors, and in front of them a larger pair whose surface is radially striated, the entire area being elongate-oval. Vascular impressions are occasionally retained in the pedicle-valve. Type, Atrypa ??iedialis, Vanuxem. Lower Helderberg group. (Delthyris shaly limestone.) Observations. In the species of this genus the internal apophysary system attains its highest development among the rhynchonelloids. Though the form of the shells is invariably elongate-, or transversely subquadrate, their internal characters demonstrate their close alliance to the subcuboidal shells of Uncind- Lus, and the genus prevails where the latter is most prolific, namely, in the 206 PALEONTOLOGY OF NEW YORK. faunas of tlie Lower Helderberg and Oriskany groups. Eatonia bears very much the same relation to Uncinulus as the subgenus Pugnax to the cuboidal shells of Hypothyris. The species of Eatonia possess two quite distinct types of exterior, one strongly plicated over fold, sinus and lateral slopes, the other radially lineate, with broad margins of contact, which are usually crenulated as if by the extremities of the rounded plications. To the former belong E. medi- alis, Vanuxem, and E. eminens, Hall, of the Lower Helderberg group, E. sinuata and E. Whitfiddi, Hall, of the Oriskany sandstone ; to the latter, E. singularis, Vanuxem, of the Lower Helderberg, E. peculiaris, Conrad, of that fauna and of the Oriskany sandstone, and E. pumila, Hall, also of the Oriskany sandstone. Gends CYCLORHINA, gen. nov. PLATE LXI. 1860. Rhyndwspira, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 83. 1867. Trematospira?, Hall. PalEeontology of New York, vol. iv, p. 412, pi. Ixiii, figs. 33-36. 1889. Retzia {Trematospira), Whiteaves. Contrib. Canadian Palaont., vol. i, pt. 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 afibrded the means of de- monstrating that the shell is not spire-bearing. The external aspect of the * Largely by Ihe favor of Professor Samuel Calvin, of Iowa CSty, 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 m.ost nearly to the type exemplified by Waagen's genus Terkbratuloidea, 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. Genus TEREBRATULOIDEA, Waagen. 1883. 1862. Rh y livhoiiella, Davidson. Quarterly Journal Geol. Soc. London, vol. -wiii, p. 29. 1863. Rhynclionella, Db Koninck. Fossiles paleozoiques de I'lnde., p. 36. 1883. Tcrebratuloidta, Waagen. Salt-Range Fossils; Brachiopoda, pp. 413-424, pl. xxxiii, figs. 1-12. Diagnosis. " Shell more or less transversely oval or rounded, in its general appearance Wiijnchonelloid, 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 ii< 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. IX. Hij. la'. Terebratuloidea Davidsoni, \Vaagen.| Fig. 15G. View of tiie exterior. Fig. 157. Interior of the pedicle-valve. Fig:. 158. Interior of tiie braciiial valve. FIG. 158. (VVaaOKX.) the median incision ver}^ 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. cii, p. 414.) Type, Terebratuloidea 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 discovery 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 Terebratuloidea to Pugnax thus appears to be that of a senile to an immature condition of development. 210 PALAEONTOLOGY OF NEW YORK. Genus RHYNCHOPORA, King. 1856. PLATE LVIII. 1844. Tei-ebratula, de Vbrnecil. Bull, de la Soc. giol. de France, vol. i, p. 27. 184.'). Terehratuhi , de Verneoii,. Guol. de la Russ. et dea Mont, de I'Onral, p. S3, pi. x, lig-s. 5 a, h. 1848. Terehratula, Geinitz. Verstein. des deutsch. Zechsteinf,'eb., p. 12, pi. iv, figs. 41, 42. 1856. Rhynchopora, King. Annals and Mag-azine of Natural History, second series, vol. xvii, p. 506, pi. xii, figs. 7-11. 1860. Rhynchonella, White. Jour. Boston Soc. Nat. Hist., vol. vii, p. 236. 1861. Rhyiu-honella, Geinitz. Dyas, p. 83, pi. xv, figs. 29-32. 1880. Rhyncliopora, David.son. British Carl). Brachiopoda, Suppl., p. 286, pi. xxxiii, tigs. 11 a-c. 1885. RhyncJtopora, Tschernyschew. Permsky Esvestnyace Kostromskoy Guberny, p. 21, pi. iii, fig. 20 ; pi. v, figs. 34-36. 1887. RJiynchupnrina, CEhlert. Fischer's Manuel de Conchyliologie, ]i. 1305. There are very few rliynchonelloid species in the Carboniferous and Permian faunas which, without evincing any essential difference from Camarot(ECHia in the character of the internal apophyses, possess a strong shell-punctation, not merely superficial but extending quite through the thickness of the valves. To one of these shells, Terehratula Geinitziana, de Verneuil, King gave the name Rhynchopora, in 1 856 ; a Permian species described from Russia, though the examples upon which King established its generic characters were obtained from the Zechstein of Germany (Ropsen). Dr. Geinitz had identified de Verneuil's species in 1848,* and in 1861f in the German faunas, and Tscher- NYSCHEwJ has more recently shown that the Russian specimens possess the shell punctation, so that there is no reason to doubt the specific identity of the type. None of the figures which have been given of this species nor of the R. Nikitini, Tschernyschew,§ also from the Permian, nor of the R Youngi, Davidson, || from the Upper Carboniferous limestone of Ayrshire, show the interior characters of the shells. From an examination of the only American species which can now be referred to Rhynchopora, namely, Rhynchonella pustulosa, White, of the Burlington limestone, it appears that the teeth are supported by conspicuous vertical lamellae, the septum of the brachial valve well developed and the *Die Versteinerungen des deutschen Zechsteingebirge, p. 12, pl. iv, figs. 41, 42. t Dyas, p. 83, pl. xv, figs. 29-32. t Op. (At., p. 21. § Op. cU„ p. 21, pl. V, figs. 34-36. 1 Suppl. Carboniferous Brachiopoda, p. 286, pl. xxxiii, figs. 11 a-c. BRACHIOPODA. 21 1 hinge-plate medially divided and without cardinal process. Externally the shells are strongly plicate with broad, low fold and sinus, and abrupt anterior slope. As far as the structure of the species of Rhynchopora is understood, the complete punctation of the shell must be regarded as the only reliable differ- ential from earlier rhynchonellid groups. The appearance of this character late in the palsBozoic history of the RnrNcnoNELLiDJi suggests its similar mani- festation in some of the Spirifers of the Carboniferous, in Syringothyris and in Spiriferina. Future study may show that the inner shell laniinas of the early rhynchonellids is not uniformly impunctate, and should this be demon- strated, the appearance in this group of a highly punctated shell like Rhyn- chopora will be more readily intelligible. It has been suggested by (Ehlert that the term Rhynohoporina may be used in preference to King's term Rhynchopora, on the ground that the latter had been previously used by Latreille for a genus of Coleoptera. The latter author's term appears to be not Rhynchopora, but Rhynchophora, and as the words are etymologically distinct, it seems best not to disturb Dr. King's term. 212 PALEONTOLOGY OF NEW YORK. CAMAROPHORIA, King. 1846. PLATE LXII. 1809. CoucJiyliiilithu.i anomitvs, Martin. Petvefacta Derbiensia, pi. xxxvi, fig. 4. 1834. Tej'eh-atula, von Buch. Ueber Terebi'aleln, p. 39, pi. ii, fig. 32. 1836. Tenlratula, Phillips. Geology of Yorkshire, vol. ii, p. 222, pi. xii, figs. lS-20. 1841. Tenhratnla, Piulmps. Palaeozoic Fossils Cornwall, Devon and West Somerset, ]). 88, jil. xxxv, fig. 158. 1844. Atrypa, McCoy. Synopsis Carb. Vossils Ireland, p. 1.54, pi. xviii, fig. 8. 1844. Camarophona, King. Annals and Magazine of Natural History, vol. xiv, p. 313. 1845. Terebi-atula, de Vkhneuil. G6o1. de la Ru.ssie, vol. ii, pp. 101-103, pi. viii, figs. ia-e. 1846. Camarophinia, King. Annals and Magazine of Natural Ilistoi'v, vol. xviii, p. 28. 18.50. Camarophoria, Kma. Monogr. Permian Fossils of England, pp. 113-122, pi. vii, figs. 10-32; pi. viii, figs. 1-8. 1854. Camarophoria, Davidson. Introd. Bntish Fossil Brachiopoda, p. 96, pi. vii, figs. 108-113. 1855. Rhyclionella, Siidmard, Geology of Missouri, p. 204, pi. c, figs. 5 6, 5 c. 1857. Camaroplioria, Davidson. British Peimian Brachiopoda, pp. 23-28, pi. ii, figs. 16-31. 1857. Camarophoria, HowsB. Annals and Magazine of Natural History, vol. xix, second series, p. 50, pi. iv, figs. 3, 4. 1858. Camarophoria (.'), Siiumard. 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. Camarophoria, Davidson. British Carbonifei-ous Brachiopoda, pp. 113-118, pi. xxiv, figs. 9-22; pi. XXV, figs. 1-12. 1860. Rhynchonella, Swallow. Trans. St. Louis Acad. Sci., vol. i, j). 653. 1860. Rhynchonella, Meek and Woethen. Proc. Acad. Nat. Sci. Philadelphia, vol. iv, second series, p. 451. 1861. Camarophoria, Geinitz. Dyas, p. 84, pi. xv, figs. 33-48. 1862. Rhynchonella, White. Proc. Boston Soc. Nat. Hist., vol. ix. p. 23. 1862. Pentameriis, White and Whitfield. Journal Boston Soc. Nat. Hist., vol. viii, p. 295. 1865. Camarophona, Davidson. British Devonian Bi-achiopoda, p. 70, pi. xiv, figs. 19-22. 1866. Camarophoria, Meek and Worthen. Geol. Survey of Illinois, vol, ii, p. 251, pi. xviii, fig 7. 1868. Rhynchonella, Mhek and Woethen. Geol. Survey of Illinois, vol. iii, p. 450, pi. xiv, fig. 7. 1881. Camarophoria, Millee. Journal Cincinnati Soc. Nat. Hist., vol. iv, p. 8, pi. vii, fig. 7. 1882. Camerophoria, Worthen. 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, Waagen. PaliEontologia Indica, ser. xiii, vol. iv, p. 435. 1883. Camerophoria, Woethen. 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. Steiioschisma, CEhleet. Fischer's Manuel de Conchyliologie, p. 1309, fig. 1095. Diagnosis. Subtrigonal, concavo-convex rhynchonellitbrm 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 tine, 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, TerebratuHtes 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- * Davidson, at various times, expressed the opinion that this specific tei'm should be regarded as a syn- onym foi- Martin "s CtmchylioVithus anmnltes crumena, fi-om the Cavljoniferons limestone. Thei-e 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. ^The Permian shell is the type of Camaropjiobia. 214 PALEONTOLOGY OF NEW YORK. tionopen 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. Camarophoria 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 rhomboidalis, 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 subtrigona, 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, Shumard, from beds considered to be of Permian age. J * Phillips' species was based upon specimens from the Carboniferous limestone of Holland (Geologfy of Yorkshire, p. 222, pi. xii, figs. 18-20. 1836). Later, in his Palaeozoic Fossils of Cornwall (p. 88, pi. xxxv, fig. 158. 1841), he i-eferred the Devonian shell to the same species, 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 gldbullna, Phillips (see Davidson, 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 Eucharis, Hall, from the Corniferous limestone, is spirigerous, and has been taken as the type of the proposed genus Camarospira. I The Camarophoria glohulina, (Phillips) Davidson, and C. Dawsoniana, Davidson, from the upper Car- boniferous of Windsor, Nova Scotia, are not Camarophoriaa but rhynchonellids, similar toij. Vta, Marcou. BRACHIOPODA. 215 There is considerable variation in exterior among the Cainarophorias. 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. Schlothei7ni, von Buch, and C. Humhletonensis, Howse, the margins of the shell are, normally, expanded as in some Devonian forms of Atrypa 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 {Pcntamerus) lenticularis, White and Whitfield, from the Yellow sandstones beneath the Burlington limestone, at Burlington, Iowa, is a shell widely diflerent 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. Genus SYNTROPHIA,* gen. nov. PLATE LXII. 18()1. Camarella, Billings. Canadian Naturalist and Geiilo{,'ist, vol. vi, p. 318. 1862. /Sfrlekla7idinia9, Billings. Palasozoic Fos.sils, vol. i, p. 85, figs. 77, 78. 1804. Oithis, A. Winchell. American Journal of Science, second scries, vol. xxxvii, ji. 2129. 1882. Leptwna, Tripleaia, Whitfield. Geology ofWisconsin, vol iv, p. 171, pi. i, figs. B, 7 ; pi. iii, fig. (i ; p. 172, pi. X, figs. 1, 2. 1886. Triplesia, Whitfield. Bull. American Mus. Nat. Hist., vol. i. No. 8, p. 303, pi. xxiv, figs. 9-11. 1892. iSyntrnphia, Hall. Palasontology of N. Y., vol. viii, part i, p. 270. In considering the spondylium-beai'ing 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. Arethusa, 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 Triplesia lateralis, Whitfield, of the Foi-t 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 different association, and it will be described and illustrated in its proper place under the name Syntrophia." — 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 surftice 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. ♦Whitfield, Bull. American Museum of Nat. History, vol. i, No. 8, p. 303, pi. xxiv, figs. 9-11. 1886. 218 PALAEONTOLOGY OF NEW YORK. The figures of Leptama Barabuensis, given by Whitfield, represent internal casts of both valves indicating the existence of a supported spondylium in each* It may be that Billings' Orihis ? 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 Tripksia 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. * Geology of Wisconsin, vol. iv, pi. i, figs. 6, 7 ; pi. iii, fig. 6. t Paleozoic Fo.ssils, vol. i, p. 303, figs, a, b, c. I Geology of Wisconsin, vol. iv, p. 172, pi. x, figs. 1, 2. 18S2. § Canadian Naturalist and Geologist, vol. vi, p. 318. ISBl. BRACHIOPODA. 219 Genera (1) C AM A R E L L A, Billings, 1859; (2) P A R A ST ROP H I A, GEN. NOV.; (3) ANASTROPHIA, Hall, 1867. PLATES LXII, LXIII. (3) 1S39. Ttrthraiula, J. de C. Sowkkby. Murchison's Silurian System, pis. xii, xiii. (2) 1847. AtrijiM, Hall. Palseontology of N. Y., vol. i, p. 144, pi. xxxiii, fig. 10. (8) 1848. Terebratula, Davidson. Bull. Soc. Geol. de Fi-ance, second seiies, vol. v, p. 328. (3) 1848. Bypofliijris, Saltkr. Mem. Geol. Survey Great Britain, vol. ii, p. 28J. (3) 1852. Atrypa, Hall. Palseontolog-y of New York, vol. ii, p. 275, pi. Ivii, fig. 2. (1) 1856. Atrypa, BillIxNgs. Canadian Naturalist and Geologist, vol. i, p. 208, figs. 20-23. (2) 1857. Pe7itamerii.s, Bihuyos. Geological Survey of Canada; Rept. of Pi-ogie.ss for 185G ; p. 295 (3) 1857. Pentamerus, Hall. Tenth Rept. N. Y. State Cab. Nat. Hi.»t., p. 104, figs. 1, 2. (3) lSr.9. Pt.ntamtriis, Hall. Twelfth Rept. N. Y. State Cat). Nat. Hist., p. 77. (3) 1859. Pentamerm, Hall. Paleontology of New York. vol. iii, p. 260, pi. xlviii, fig. 1. (3) 1859. Mliynchonella, Salter. Murchison's Silui-ia, ]>. 544, pi. xxii, fig. 10. (1) 1859. Camarella, Billings. Canadian Naturalist and Geologist, vol. iv, pii. 301, 302, 445, tigs. 23, 24. (3) 1860. Rhynchonella, Lindstrom. Gotland's Brachiopoden, p. 366. (1) 1861. CamareWo'., Billings. Geology of Vermont, vol. ii, p. 949, fig. 353. (1) 1861. Camarella, Billings. Palaeozoic Fossils, vol. i, p. 10, fig. 13. (2) 1862. Camarella, Billings. Palseozoic Fossils, vol. i, j). 148, figs. 128, a, b. (1) 1863. Camarella, Billings. Geology of Canada, p. Iii7, figs. 52, 53; p. 143, figs. 77, 78; p. 168, fig. 154 ; p. 284, fig. 290. (3) 1863. Pentama-us, Billings. Geology of Canada, p. 957, fig. 453. (3) 1865. BracliymeriLH, Siialer. Bull. Mus. Comparative Zoology, No. 4, \t. 69. (1) 1865. Camarella, Billings. Paleozoic Fossils, vol. i, pp. 219, 304, fig. 295; p. 305, fig. 297. (1) 1866. Camarella, Billings. Catalogue Silurian Fossils of Anlicosti, p. 45. (3) 1867. Aii.antroplila, Hall. Twentieth Rept. N. Y. State Cab. Nat. Hist., p. 163. (3) 1867. Anastivphia, Hall. Paleontology of N. Y., vol. iv, p. 374. (3) 1869. Rliynchunella, Davidson. British Silurian Bi'achiopoda, p. 178, id. xxii, figs. 24-27. (3) 1879. Aiiastrophia, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p. 16S, pi. xxvi, figs. 41-49. (3) 1882. Avastropliia, Hall. Eleventh Rejit. State Geologist of Indiana, p. 311, pi. xxvi, figs. 41-49. (2) 1883. Rhy7icho7iella, Davidson. British Silurian Brachiopoda, Suppl.,p. 201, pi. xi, figs. 26a-rf. (1) 1883. Stricklandhiia ?, Davidson. British Silurian Brachiopoda, Suppl., p. 166, pi. ix, figs. 27-29. (1) 1886. Camarella. Walcott. Bull. U. S. Geol. Survey, No. 30, p. 122, pi. vii, fig. 8. (1) 1889. CamarellaffVfALCOTr. Pi'oc. U. S. National Museum, vol. xii, p. 36. (3) 1889. Anastropliia, Bekcher and Clarke. Memoirs N. Y. State Museum, p. 32, pi. iii, figs. 14-16. (3) 1889. Anatitruphia, Nettelroth. Kentucky Fossil Shells, p. 47, pi. xxxii, figs. 17-20. (1) 1890. Camarellaf, Walcott. Tenth Ann. Rept. Director U. S. Geological Survey, p. 614, pi. ixxii, figs. ia-d. CAMARELLA, Billings. 1859. PLATE LXII. 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 Volboithi, BiWmgs, 220 PALEONTOLOGY OF NEW YORK. ' from the Black 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 has 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 lamellse 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 Avide 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 ? £alcletchiensis,f a rather large rhynchonelliform shell with a short spondylium in the pedicle-valve, and without cardinal area. PARASTROPHIA, CxEN. nov. PLATE LXIII. Among the species which have been currently referred to Camarella are the well-known Atrypa hemiplicata. Hall, of the Trenton fauna, and the Pmtamerus reversus, :j: 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 t;ardinal margin is moderately long and nearly straight, but there is no evidence of a cardinal area on either valve. * Tenth Ann. Rept. Director U. S. Geological Sui'vey, p. 614, pi. Ixxii, Bgs. ia-d. 1S90. t See Davidson, Silurian Brauhiopoda, Siippl., p. 166, pi. ix, figs. 27-29. X The latter has also been referred by different writers to A.vastrophia and Tkipleuia. 222 PALAEONTOLOGY 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 lamellae make a strong spondylium which reaches almost to the bottom of the valve, being supported by a very low median septum extending ne.arly 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. latipUcata 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 * This form is much less extended than Atrypa ?iemipUcata, Hall ; its plications are larger, sharper and fewer in number, and distinctly raai-ginal. It is a shell quite different from the Trenton species, and may be termed Parastropltia divergens. BRACHIOPODA. 223 the inner surface of the valve (P. latiplicata, P. mulliplicata). 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. mvltiplicata 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 wliich are above referred to Pakastropiiia, are probably to be added the Rhynchonella Scotica, Davidson, from the Llandeilo of Ayrshire,* and the Pentamerus {Alrypa) rotundaius, 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. bnrussica, 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 Brachiopoda, Suppl. p. 201, pi. xi, figs. 26 o-d. t Silurian Brachiopoda, p. 150, pi. xv, figs. 9-12 224 PALAEONTOLOGY OF NEW YORK. ANASTROPHIA, Hall. 1867. PLATE LXIII. Under the term Anastrophia has been grouped a number of species with reversed convexity, the disparity of the two valves in this respect surpassing that prevailing in Parastrophia. Their external surface is covered with numerous fine and sharp dichotomizing ribs, extending to the apices of the beaks and frequently crossed by delicate concentric lines. The type of this genus is the Pentamerus Verneuili, Hall, of the Lower Plelderberg shaly lime- stone, and with it are to be associated the Atrypa interplicala, (Sowerby) Hall, and Anastrophia internascens, Hall, of the Niagara group ; the Terebratula deflexa, Sowerby, of the Wenlock limestone, and the shell passing under the same name in a cori'esponding fauna of the Island of Gotland. In this group again, the internal apophyses are subject to some variation. The spondylia of the valves are quite large, extending not less than one-third the length of the shell. As in Parastrophia, that of the pedicle-valve is the wider and is supported by a median septum near its anterior extremity. In the earlier species, A. internascens, A. deflexa, this spondylium may be thus sup- ported for nearly or quite its entire length, but in A. Verneuili, the latest repre- sentative of the group, the structure is usually the same as in later members of Parastrophia. On Plate LXIII is given a figure of an interior of this species in which the lateral walls of the spondylium have folded, one over the other, and thus formed a tubular cavity open at both ends. What the significance of this modification may be, can not be judged from the single specimen. In the brachial valve the convergent plates generally rest upon the inner surface of the shell, though at times, in A. Verneuili, the spondylium is supported at its anterior extremity. The crural plates are extravagantly developed, forming two broad wing-shaped vertical expansions, concave on their outer surfaces ; their upper edges are curved over the hinge-line, their anterior edges broadly notched, and below this point appears the base of attachment for the crura ; the walls of the spondylium being connected with them at the most convex point of their inner surfaces. The dental sockets are always small, and old shells frequently show a false foramen in the beak, which is simply an exten- BRACHIOPODA. 225 sion of the spondylium that does not appear to l)c accidental. The muscular impressions of tliis valve are frequently defined as a fourfold scar about the anterior end of the spondylium ; in the pedicle-valve these impressions are rarely discernible. It has been shown that in early age the shells of Anastropiiia are normally biconvex, and the brachial valve scarcely deeper than the opposite.* In this condition the form of the shell resembles that of normal individuals of Cama- rella Volborthi, and in this series of forms, beginning in Camarella where senile shells evince a gibbosity of the brachial valve and a tendency toward reversion of convexity, and ending with the Lower Helderberg Anastrophia Verneuili, we have a consecutive and gradational development in internal structure, wliich is accompanied by more abrupt variations in exterior. On the basis of the former it would be difficult to apprehend where division lines should be drawn, but the differences in the latter afford immediate and reliable means of distinction. Genus PORAMBONITES, Pander. 1830. PLATE LXUI. 1820. TerebratuHtes, Schlotheim. Petrefactenkunde auf ihr. jetz. Stan(ipiinkt, p. 282. 1830. Poi-amh(mU(S, Pahder. Beitr. zui- Geogn. des riiss. Reii'hes, pp. 95-100, pi. iii, fig. 9 ; pi. xi, figs. 1-8 ; pi. xii, figs. 1-8 ; pi. xiii, figs. 1-7 ; pi. xiv, figs. 1-4 ; pi. xv, figs. 1-4 ; pi. xvi A, fig. 12 ; pi. xviB, tig. 7. 1834. Terehrattda, vos Bvcn. Ueber Terebratein, p. 104. 1840. Spirifer, ton Buck. Beitr. zur Kennt. Gebirgsform. Russl., pp. 13, 16, pi. ii, figs. 2-7. 1840. Tenhratula, von Eichwald. Silurian System in Estland, pp. 132, 135. 1845. iSpirlfei; de Vernedil. Geol. de la Russie et des Mont, de I'Oiiral, vol. ii, pp 127, 130-134, pi. ii, figs. 2, 3 ; pi. iii, fig. 1. 1847. Pvi-ambonites, d'Okeignt. Paleontologie Fran^aise ; Tei-r. Cret., vol. iv, p. 345. 1850. Isorhynchafi, Kl.VG. Monogr. Pei-mian Fossils of England, p. 112. 1852. Purambonilcs, von Eichwald. Lethiea rossica, vol. i, p. 793. 1853. Poramhonites, Sharpe. Quarterly Journal Geol. Soc. London, vol. ix, p. 155. 1854. Porambojiites, Davidson. Introd. Bi-itish Fossil Brachiopoda, p. 99, pi. vii, figs. 120-126. 1869. Porambonitcs, Davidson. British Silurian Brachiopoda, p. 195, pi. xxv, figs. 16a-rf. 1877. Parambonites, Hall and Whitfield. King's U. 8. Geol. Exjil. Fortieth Parallel, p. 234, pi. i, fig. IB. 1889. Pwambonites, Noetling. Zeilschr. der deutsch. geolog. Gesellsch., vol. xxxv, p. 355, pis. xv, xvi. 1890. Porambouites, Gagel. Bnichioii. dei- camb. uud silur. Geschiebe im Dihiv. der Provinz. Ost- and Westpreussen, pp. 50-52, pi. v, figs. 1-7. * See Bebcher and Clarke, Memoirs N. Y. State Museum, vol. i. No. 1, p. 32, pi. iii, figs. 14-16 a. 1889. AnoDtrophia intei'nasceiis, Niagara group. 226 PALEONTOLOGY OF NEW YORK. " Shell robust, transverse or elongate, sometimes distinctly triangular and globose. Valves unequally convex, the dorsal always the deeper. Ventral valve with a sinus to which there is not always a corresponding fold on the dorsal valve. Hinge-line straight; hinge-teeth very strong, resting on a broad hinge-plate. In both valves a small obtusely triangular area, which is higher in the ventral than in the dorsal valve. Both valves with a broad pedicle- passage, never closed by a pseudodeltidium. Sometimes the beak of the dorsal valve is so strongly incurved that its perforation is not visible from outside. On the lateral slopes is a more or less strongly defined pseudolunule* " In the interior of the ventral valve are two long, robust dental lamellae which rapidly converge and unite, sometimes before the bottom of the valve is reached, then forming a low median septum. Their anterior portion is always free while their posterior portions are sometimes coalesced into a single piece. In the dorsal valve there are two short crural plates not rising to more than one-third the height of the shell ; these may remain independent or sometimes unite to form a single piece. " The muscles are attached between and on the convergent plates, and, in the dorsal valve, also in front of them. " Surf\\ce-sculpture more or less finely sieve-like. " Shell-structure apparently fibrous. " All species are confined to the lower Silurian." Type, Porambonites intermedia, Pander, f The above diagnosis is that given by Noetling, in an admirable paper on the structure and .systematic position of the genus.| Although so old a genus and so abundantly represented in the Silurian fiiunas of Russia, no satisfactory conclusion as to its generic affinities had been reached until the publication of this author's investigations, to whose figures of the interior structure of the valves, obtained from silicified specimens, the student is referred for illustration supplementary to that given in this Volume. * This term is applied by Nobtling to an area on the cardinal slopes usually delimited by some sharply defined growth-line of an immature stage of development. It designates a feature of slight morphological value. t Beitrage zur Geognosie des russischen Reiches, p. 95, pi. xvi A, fig. 12. 1830. J Beitrag zur systematischen Stellung des Genus Porambonites, Pander; Zeitschrift der deutschen geologischen Gesellschaft, vol. xxxv, p. SS.'i, pis. xv, xvi. 1883. BRACHIOPODA. 227 Pander described thirty-one species of Porambonites, all of which were directly absorbed by von Buch into the genus Spirifer of his conception* De Verneuil, in the Geologic de la Russie,f included these species in his division " Spirifer anormaux," section " Equirostri'S," corresponding to the section " Biforcs," which embraces species of the genus Platystrophia, King. This author placed eleven of Pander's species under von Bucu's Spirifer 'porambonites, 1840, and eight others as synonyms of Schlotheim's Terebratulites aquirostris, 18-0. After d'Orbigny's resuscitation of Pander's term,t and suggestion of the relation of the genus to the rhynchonelloids, the name again became current,§ Sharpe II and EiCHWALDTf indicating the affinities of the shells to the pentame- roids, the latter considering its position intermediate between them and the strophomenoids. Davidson, in his Introduction to the Brachiopoda, placed Porambonites in a family by itself, Porambonitid.js. regarding its place as between the Rbyncuokel- LID.E and STROPHOMENiDyE. NoETLiNG elaboratcs this conception, placing Poram- bonites and Pentamerus in one family, Poramboxitwje, regarding the position of this family as " between the Strophomenidjs, with which it is connected through Porambonites, and the Rbtncbonellid^, by way of Pentamerus and Camarophoria " (p. 378). After a careful study of Noetling's figures of the interiors of these shells, it becomes evident that the most direct relationship to these fossils is to be found in those pentameroids which have been designated as Parastrophia and Anastrophia. The frequent great size and thickness of the shells of Poram- bonites accounts for a certain degree of obscuration of interior detail, but in all these genera we find the well-developed and supported spondylium in the * Beitrag zur Kenntniss der Gebirgsfoiuiat. RusslanJs, p. 13. 1840. t Op cit, p. 127. 1S45. I Palfiontologie Fran5aise ; Terr. Cret., vol. iv, x>- 345. 1847. § Meanwhile Kisd, in ignorance of Pander's term, had proposed the name IsoRHYKcnus, with Schlot- heim's Spirifer wquirostris as the type. He found the genus bearing relation to Pe.ntameru.s, Camaro- phoria, etc. 1 Quarterly Journal Geological Sociely, vol. ix, p. 155. 1853. % Lethrea i-ossica, vol. i, p. 793. 228 PALEONTOLOGY OF NEW YORK. pedicle-valve, and the convergent plates of the opposite valve which may or may not unite before the surface of the valve is reached.* Again, it has been already observed that Anastkophia possesses an uncovered foramen in each valve, and this may also be true of Parastrophia, but in Porambonites a cardinal area is retained on both valves, and this character, more than any other, serves to show the derivation of these shells to be from the same ancestral stock as Orthis and its allies. In external characters there is also an agreement in contour with the genera named. The shells of Porambonites are frequently gibbous, the convexity of the brachial valve usually exceeding that of the pedicle-valve. The punctate ornament of the exterior lamina is purely superficial. While Porambonites is so abundant in the Silurian strata of Russia and Scan- dinavia, its representation in the American faunas is most meager, if indeed it exists here at all. The species Porambonites Ottawaensis, Billings, from the Black River limestone, does not belong to this genus, but is probably a member of the proposed group Orthorhynchula ; the Porambonites obscurus, Hall and Whitfield, described from the lower Silurian of the White Pine District of Nevada, f is known only from a single pedicle-valve, which may prove a representative of the genus, and, if so, the only one recognized in our faunas. The species which was the first of de Verneuil's group of " Spirifer anormaux equirostres," S. Tscheff- ^- ^^^ kini, de Verneuil,| from the lower Silurian of the ZT^" 19 environs of St. Petersburg, has a general external ^^'^ssi&as^' resemblance to species of Porambonites, but the fig. isa. Tl r-j.1 1 • 1 I'll A cardinal view ol' a specimen of cardmal area of the valves is much more highly spiH/er i^Koaungia) TscheffUni. developed and extends for nearly the width of the shell. So far as we know, the character of its interior has never been dem- * Attention has already been directed to a slight vai-iation in all these genera in i-egai'd to the ai-tual degree of union in the lamella; of this valve. In Parastrophia they are normally confluent, though P. di- vergent furnishes an exception to the rule in having them free to the bottom of the valve. In Porambonites they appear to be normally discrete. t In King's U. S. Geological Explorations Fortieth Parallel, p. 234, pi. i, fig. 16. 1877. I Geol. de la Rus.sie, etc., p. 129, iil. ii, ligs. 1, a, h. BRACHIOPODA. 229 onstrated, though Noetling mentions {he. cit., p. 368) having seen a specimen showing the internal characters, which convinced him that it could not be a true Porambonites. The nature of these features, however, is not stated. Well preserved interiors of this shell must be of rare occurrence and opportunity is taken therefore of elucidating its structure by a series of trans- verse sections from the beaks forward. It will be seen from these accompany- ing figures that there is a spondylium in each valve, that of the pedicle-valve being at the outset the larger, and continuing further forward than the other. Both are supported by a stout median septal callosity, which, in the brachial Fig. 160. Fig. 161. Fig. 162. Fig. 163. Fig. 164. FIG. 165. Fig. 166. Figs. 160-166. Transverse serial sections of a single specimen of Spirifer [NoetUngia) Tsckeffldni, showing the structure of the internal apophyses and septa. In all the sections the pedicle-valve (P) is above, the brachial valve (n) below. (0-1 valve widens and becomes lost in the thickened shell-substance of the muscular region ; that of the pedicle-valve becomes narrowed anteriorly and eventually leaves the spondylium free, or nearly so. These characters are not materially different from those of Porambonites, but a feature of high significance in Spirifer Tscheffkini is the presence of a simple linear cardinal process in the spondylium of the brachial valve. This, with the long, double-areaed hinge- line, the biforate umbones and suggestive external resemblance in contour to Platystrophia, forms a more strongly orthoid combination than has been here- tofore observed among shells with such pronounced pentameroid affinities, and thus makes a more direct connection between Porambonites and the orthoid stock whence they have all been derived. The distinctive generic value of this shell as above expressed may be indicated by the term Noetlingia. 230 PALEONTOLOGY OF NEW YORK. Genus LYCOPHORIA, L ahusen. 1 885. PLATE LXIII. This name lias been proposed for the Atrypa nucella, Dahnan, a species not unlike Porambonites in general external features. The valves are rotund and have neither fold nor sinus, so that the anterior margin of contact is almost straight or very gently sinuous. The beaks are full and closely incurved and only the pedicle-valve appears to have retained a foramen, though the cardinal area is present in both. The brachial valve bears a hinge-plate which is recurved into the pedicle-cavity of the opposite valve and is produced into a long, curved cardinal process, bifurcate at its extremity. The crural plates are connected with the elevated margins of the four adductor impressions. In the opposite valve the teeth are supported by divergent plates which extend forward for about one-half the length of the shell and rest upon the bottom of the valve. Externally the shell is smooth in the umbonal regions, but anteri- oi'ly is covered with low, rounded plications crossed by fine concentric lines. The systematic relations of this species are very interesting. It is associa- ted with Porambonites in the lower Silurian faunas about St. Petersburg and in Scandinavia, and its similarity to that genus in contour and, to a certain extent, in details, is apparent. While Porambonites is strongly orthoid in the structure of its cardinal feat- ures, and Noetlingia possesses the simple linear cardinal process of Platystro- phia, Atrypa nucella adds to these orthoid features the cardinal process of a streptorhynchoid, like Triplegia and Mimulus, thus presenting another point of tangency between these shells and the pentameroids ; or, more precisely, another phase in the development from the comprehensive primordial stock represented by Protorthis, Billingsella, etc., toward the full and typical expression of Orthis, Orthothetes, Strophomena and Conchidium. BRACHIOPODA. 231 Genus CONCHTDIUM, Linne. 1753. PLATES LXIV, LXV. LXVI, LXVII. 1753. ConcMdium, Linne. Museum Tessinianum, p. 90, \i\. v, figs. 8, a, b. 1766. HelminVwlitus, Linne. Sy.stema Naturae, ed. xii, vol. iv, p. 163. 1798. Atwinites, HisiNriER. Minerograph. Anmerkning. ofvei- Gottlaiid ; Vet. Akad. Handling-, p. 285. 1813. Pentamerits, Sowkrby. Mineral Conchology, vol. i, p. 73, pis. xxviii, xxix. 1828. Qypldia, Daiman. Kongl. Vetenskaps Aka to be merged between the two varieties, it will be better, and in accordance with rule, to assume the shell known as var. crassi- costa, the first of the varieties named, as the typical form of P. Nysiv^. For the other variety the name ConcUdlum tenuicosta will be used in preference to Nettelroth's proposed term P. compUmatns (lib. cit., p. 53). t Canadian Record of Science, p. 295. 1891. X It may be well to verify the geological horizon of this species before basing any conclusions upon its occurrence in the Coi-niferous limestone. § Zeitschr. der deutsch. geol. Gesellsch., vol. xl, p. 588. 1888. 236 PALJEONTOLOGY OF NEW YORK. Genus PENTAMERUS, Sowerby. 1813. PLATES LXVII, LXVIII, LXIX, LXX. 1S13. Pentamcriis, J. Sowerby. Mineral Conohulogy, vol. i, p. 76, pi. xxviii. 1839. Pentamerus, J. dk C. Sowerby. Silurian System, pi. xix, tigs. 9, 10. 1843. Pmtameru.n, Hall. Geology of New York ; Kept. Fourth Dist., p. 70, figs. 1-5. 1845. P(7itamems, de Vekneuil. Geologie ile la Russie, p. 119, pi. viii, figs. la-c. 1852. PCTitamer/M, Hall. PaliEOntology of New Y'ork, vol. ii, p. 79, pi. xxv, figs, lo-m; pi. xxvi, figs. 1 a-d ; p. 103, pi. xxxi, fig. 1. 1854. Pentamenis, Eichwald. Bull. Soc. Imp. Natural. Moscou, pt. 1, p. 91. 1854. Peiitmner-iLS, F. Schmidt. Neueste Untersuch. ueber Brachiopoden, p. 213. 1859. Pentamerus, Eichwald. Lethica rossiea, vol. i, p. 788, pi. xxxiv, fig. 23. 1861. Pujitaiiierus, McChesney. New Palaeozoic Fossils, p. 85. 1863. Pentainerus, Billings. Geology of Canada, p. 316, fig. 326. 1866. Pentamerus, Billings. Catalogue Silur. Fossils Anticosti, p. 45. 1867. Pentamerus, 'Da\id&os. British Siluj'ian Brachiopoda, p. 151, pi. xviii, tigs. 1-12 ; pi xix, tigs. I, 2. 1867. Pentamerus, Hall. Pala;ontology of New York, vol. iv, pp. 369-374. 1868. Pentamerus, McChesney. Trans. Chicago Acad. Sci., vol. i, pi. ix, tig. 1. 1872. Peiitamerm, Hall and Whitfield. Twenty- fourth Ann. Rept. N. Y. State Mus. Nat. Hist., p. 183. 1875. Pentamerus, Hall and Whitfield. Twenty-seventh Ann. Rept. N. Y. State Mus. Nat. Hist., pi. X, figs. 13, 14. 1875. Pentamerus, Hall and Whitfield. Paliieontology of Ohio, vol. ii, pp. 137, 139, pi. vii, tigs. 9-11. 1882. Pentamerus, Whitfield. Annals N. Y. Acad. Science, vol. ii, p. 195. 1882. Pentamerus, Whitfield. Geology of Wisconsin, vol. iv, pp. 288, 291, pi. xvii, figs. 3-9. 1889. Pentamerus, Netfelroth. Kentucky Fo.ssil Shells, pp. 60-62, pi. xxix, tigs. 23, 24 ; pi. xxx, figs. 2-4. 1889. Pentamerus, Foerste. Proc. Boston Society Nat. Hist., vol. xxiv, p. 324, pi. v, figs. 17, 18. 1890. Pentamerus, Whitfield. Annals N. Y. Acad. Sci., vol. v, p. 513, pi. v, figs. 11-22. 1890. Pentamerus, Gagbl. Die Brachiop. der camb. und silur. Gescbiebe im Diluvium der Provinzen Ost- und Westpreussen, p. 53, pi. iv, fig. 1. Since it seems necessary to restrict the term Conchidium to those pentame- roids embraced by de Verneuil in his division " plissus, sans sinus," it becomes desirable to apply the designation Pentamerus to the second division of those shells, the " lisses, sans sinus." This use of Sowerby's term is in precise accordance with recognized rules of nomenclature. The first species cited by Sowerby, and that which has been generally regarded as typical of the genus by authors who have preferred this term to the earlier designation of Linne, is P. Knighti, a plicated shell, which belongs to Conchidium.* The second of Sowerby's typical examples, and that to which must be accorded his generic * The P. Aylesfordi, Sowerby, cited in the " Mineral Conchology " as another of the typical species of Pentamerds, was subsequently regarded by that author as a synonym for P. Knighti (Silui-ian System, p. 615, 1839), and the name has consequently fallen into disuse. BRACHIOPODA. 237 term, is the Pentamerus lavis, a shell with a smooth exterior, and of which Mr. Davidson remarks : * " It is admitted now by palajontologists that P. Icevis, Sow., is the young of P. ohlongus; and if it were necessary to strictly adhere to rules of priority, James Sowerby's name, published in August, 181.3, 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 oblongtis." Pentamerus oblongus 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 siives 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. * Siliiiian Brachiopoda, p. 153. 238 PALEONTOLOGY OF NEW YORK. The same form of shell occurs rarely in Wisconsin (Door county), and has been described by McChesney as P. bisinuatus* 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 FrG. 1G9. Fig. 170. Fig. 171. Fiu. Xli. Fig. 169. Peniamerus oblongus, Sow e\hy. A tiansverse section, showing the septa. (C.) Figs. 170, 171. Transverse sections ol' the sejita of Pentamenis oblongus. Fig. 170 shows the septum of the pedicle- valve and the enclosure of its bate by the shell-substance of the valve. Fig. 171 is an enlargement of the septa of the brachial valve, and shows a thin coating of testaceous matter upon the inner faces of the ]>rismatic walls. (C.) Fig. 17-. Pentamerus cylindricus, Ilall. A transverse section, showing the septa. (C.) lobation of the apical end of the spondylium is the sole evidence of a cardinal process. The depth of the spondylium and septa varies Avith the convexity of * Descriptions of New Sjiecies of Fossils, p. 85, pi. ix, fig-. 1. 1859. BRACHIOPODA. 239 the valves ; usually, however, the septa of the brachial valve are very short and rest upon the inner surface of the shell. It sometimes happens that these septa unite before reaching the inner surface, and the spondylium thus formed is supported by a very low axial septum. This is the case in the original specimen of P. bisinuatus, McChesney, and in the Wisconsin shell refer- red to that variety by Whitfield.* It is more conspicuously developed in the Iowa shell which has just been mentioned as P. oblongus, var. subredus, and it serves to confirm the varietal character of that form. It has been already observed that the union or independence of these dorsal septa in the genera Anastrophia and Parastrophia can be regarded as a feature of only secondary importance. In the later pentameroids it will be found that the difference becomes fixed and of more positive significance, but in the Silurian shells it is still a variable feature, but not of usual occurrence. At times an exceedingly faint obsolescent radial plication of the exterior is observable in P. oblongus, and this feature is also occasionally apparent in P. pergibbosus, Hall and Whitfield, and more noticeable in P. occidentalis, Hall, of the Guelph fixuna of the Province of Ontario, and of the Niagara fauna of Ohio and Wisconsin.! * Geoldgy of Wisconsin, vol. iv, p. 290, pi. xvii, fig'. 3. IM82. t The shells which are cuvi'enlly refeneii to Pentamerus pergibbosus also vary noi a little among them- selves, and it would be no ditticult matter to accjuire a series of foims to demonstrate that this is but another extreme of development which has originated in P. oblongus. The originals of P. pergibbosus from the Niagara dolomites of Darke county, Ohio, are rather small shells with long, oblique caidinal slopes, nar- row umbones and very deep valves. In the limestones about Milwaukee shells of this character attain great size, and in the chert of Jones county, Iowa, occurs a very small shell which cannot be separated from this species by any decisive chai'acters. Mr. Whitfield has figured J as one of the variations of P. oblongus, a gibbous shell from the upper coral beds of the Niagara gi-oup at Ashford, Wisconsin ; a similar, though persistently smaller shell abounds in the dolomites of the Maquoketa region near Dubuque, and at Hopkinton, Iowa. The latter has been generally identified as P. pergibbosus. It is, however, (luite a diti'erent shell fi-om that occiiring in Darke county, Ohio, its fnll, rotund valves, tiroad aci-oss the cardinal region, producing an expression dis- tinct from that of P. pergibbosus, while the suggestion of trilobation of the sui-face which is shown on all the specimens examined, indicates ils nearer relations to P. oblongus; as a cori-ected identiticalion of this shell, the name P. oblongus, var. Maquoketa, is suggested. It is observed above that the variety of P. oblongus, prevailing in Ohio (var. bidnuatus), is represented with extreme rarity among the Clinton shells of New York. Similarly, the variety Maquoketa is known to occur on this side of the Mississippi only, in the Wis- consin locality cited. On Plate LXVIII, figure 13, there is given a figure of a shell of great size, probably from Indiana, which is nearer to this than to any other form of P. oblongus. The diflferences between P. pergibbosus and the P. occidentalis. Hall, from the Giielph fauna are also obscure. The latter has the cardinal slopes very broad, the axial slopes flattened or depressed and the } Op. cit., pi. xvii, figs. 8, 9. 240 PALEONTOLOGY OF NEW YORK. It is evident from the foregoing remarks that Pentamerus is an exceedingly plastic type, and its duration is essentially the same in all countries. Davidson finds P. oblongus restricted to the lower and upper Llandovery rocks. In the Baltic Provinces of Russia the species P. borealis, von Eichwald, a shell very similar to that variety of P. oblongus, here termed subredus, occurs in agglom- erations (Borealis-bank) like those of P. oblongus in the Clinton limestone, at a low horizon in the upper Silurian. Above this is the zone of P. Esthonus, another form very close to P. oblongus. In Scandinavia, P. oblongus is found in a higher horizon, which corresponds more nearly with its occurrence in the Niagara dolomites of the interior States. P. Samojedicus, Keyserling, from the Petschora-land is still another smooth species from a corresponding horizon. shell subquadrate in transverse section. The surface, in the usual preservation of the shell, has sti-ong con- centric, often squamous growth-lines and distinct traces rf radiating plications. It is doubtful if these plications were ever strongly developed, and in any considerable collection of sjiecimens it is easy to demonstrate the gradation of this species from P. peryibhosus. In association with this shell at Guelph there occurs an undescribed species of a well-defined Conchidiom, not unlike the plicated shell referred by Whitfikld (op. cit., p. 314, pi. xxiii, figs. 1, 2,) to P. ocddentalis. BRACHIOPODA. 241 Genera (l)BARRANDELLA, nom. propos. ; (2) P E N T A M E R E L L A, Hall, 18o7; (3) SIEBERELL A, (Ehlert, 1887; (4) GYPIDUL A, Hall, 1867. PLATES LXXI, LXXII. (3) 1827. Atrypa, Dalman. Kongl. Vetenskaps. Acad. Handlingar, p. 180. (3) 1834 Terebratula, von Buch. Uebei' Terebi-ateln. (3) 1839. Atrypa. J. de C. Sowkrby. Silurian System, jil. xii. fig. 4. (1) 1839. Atrypa, J. de C. Sowerbt. Silurian System, pi. xiii, fig. 8. (2) 1841. Atrypa, Conrad. Geol. Survey N. Y. ; Ann. Rept. Palseont. Dept., p. 55. (3) 1S43. Terebratula, A. Roemer. V'erstein. des Harzgebirges, p. 19, pi. xii, fig. 25. (3) 1845. Pentamerns, de Vernkuil. Geologie de la Ru.ssie, etc , vol. ii, p. 120, pi. viii, figs. 'ia-g. (I) 1818. PentameriLS, Davidson and dk Vernkuil. Bull. Soc. Geol. de France, second .ser., vol. v, pp. 333, 346 (4) 1852. Atrypa, Owkn. Geol. Survey Wisconsin, Iowa ami Minnesota, p. 583, pi. iiiA, tig. 4. (1) 1852. Pentamerus, Hall. Paleontology of New York, vol. ii, y. 81, pi. xxiv, tigs. 1 a-d. (2) 1857. Pentameras, Ki.LL. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 120, tigs. 1-10. (1) 1857. Petitainerun, Billings. Rept. Piog. Geol. Survey of Canada, p. 29(5. (3) 1857. Pentamerits, Hall. Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 105, tigs. 1-3. (t) 1858. Pentamerus, K. Schmidt. Silur. Format. Rsllands ; Archiv fiir Naturkunde, vol. ii, p. 212. (4) 1858. Pmtaiiierux. Hall. Geology of Iowa, vol. i, pt. 2, p. 514, pi. vi, figs. 2 a-c. (3) 1859. Pentaiiurua, Hall. Palajontology of New York, vol. iii, p. 257, pi. xlvi, tigs. I a-z ; pi. xlvii, tigs. 1 a-m. (3) 1859. PentameriU!, von Eichwalu. Lelhaea rossica, vol. i, pi. xxxv. tigs. 19, 20. (1) 1860. Pentame)-us, Lind,str6ji. Ofversigl kongl. Veten. Acad. Forhandl., p. 365, pi. xii, tig. 6. (2) 1860. Pentamerus, Spirifer, Hall. Thirteenth Ann. Rept, N. Y. State Cab. Nat. Hist., pp. 86, 90. (3) 1860. Pentamerus, F. Roemkr. Silur. Fauna des westl. Tennessee, p. 73, pi. v, fig. 11. (1) 1861. Pe«ia(ftCT?i.s, Hall. Rept. Pi-ogre^s Geolog. Survey Wisconsin, p. 2. (1) 1863. PertinMerii-s, Billings. Geology of Canada, p. 316, fig. 327. (3) 1865. Pentamerus, Winchell and Marcy. Mem, Boston .Soc. Nat. Hist., vol. i, p. 94, pi. ii, tig. 11. (1) 1866. Pe«/ame?'?<5, Billings. Catalogue Silurian Fos.sils Anlicosti, p. 45. (4) 1866. Pentamerus, Meek and Worthen. Geol. Survey Illinois, vol. ii, p. 325. (1) 1867. Peutamtrus, Davidson. British Siluiian Brachiopoda, p. 149, pi. xvii, tigs. 11-14. (1) 1867. Pentaintrus (Pcntaiiterella), Hall. Twentieth Ann. Rept. N. Y. Stat<' (^ab. Nat. Hist., p. 374, pi. xiii, tigs. 18-21. (2) 1867. Pentamerella, Hall. Paheontology of New York, vol. iv, pp. 373, 375-379, pi. Iviii, figs. 1-21, 24-43. (3) 1:67. Pentaiuerus, Davidson. British Silurian Brachiopoda, p. 145, pi. xv, figs. 13-23. (4) 1867. Gypklula, Hall. Paleontology of New Y'ork, vol. iv, pp. 373, 380, 381, pi. Iviii, figs. 22, 23 ; \i\. Iviii a, figA. 1-8. (4) 1868. Pentamerus, Meek and Worthen. Geological Survey of Illinois, vol. iii, pp. 428, 429, pi. xiii, tigs. 5, 6. (1) 1871. Pentamerus, Quenstedt. Pelrefactenkunde Deutschlands ; Brachioiioden, p. 222, pi. xliii, figs 44, 45. (1) 1875. Pentamerus, Hall aiul Whitfield. Paleontology of Ohio, vol. ii, p. 13S, pi. vii, tigs. 7, 8. (3) 1878. PentameriLS. Kaysbr. Abhandl. zur geol. Specialkarte von Preussen, etc.. Bud. 2, Heft 4, pp. 156-159, pi. xxvii, figs. 1-9, 13. (4) 1878. Gypldula, Calvin. Bull. U. S. Geol. Survey of the Terr., vol. iv, p. 730. (1) 1S70. Pe?i/rt»ifr«s, CTormffa, Barkande. Sysleme Silurien, vol. v, pis. xxii, xxiv, cxix, cxxxviii. (1) :882. (1) 1882. (3) 1883. (4) 1884. (1) 1887. (3) 1887. 242 PALEONTOLOGY OF NEW YORK. (3) 1879. Pentamerus, Bakkandb. SystSme Sihnien, vol. v, pis. xx, xxi, xxiii, Ixxvii, Ixxviii, Ixix, cxvi, cxvii, cxviii, cxix. Pentamtnis, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 299, pi. xxvii, tig. 15. Peiitamerus, Whitfield. Geology of Wisconsin, vol. iv, p. 291, pi. xvii, figs. 11-13. Pentameriis, Davidson. Biitisii Silurian Brachiopoda, Suppl., p. 164, pi. ix, figs. 25, a. Gypidula, Walcott. Monogr. U. S. Geol. Survey, vol. viii, p. 159-161, pi. iii, figs. 4, 7; pi. xiv, fig. 15 ; pi. XV, fig. 5. AntirhyncJionella, Q5hlert. Fischer's Manuel de Conchyliologie, p. 1311. SiehereUa, (Ehlert. Fischer's Manuel de Conchyliologie, j). 1311. (1) 1889. Pentamerus, Nbttblhoth. Kentucky Fossil Shells, p. 1)4, pi. xxiii, figs. 12-14. (3) 1889. Pentamerus, Neitelroth. Kentucky Fossil Shells, jip. 59, 63, pi. xxvii, figs. 25-27; pi. xxxiii, figs. 25-29, 31-33. (1) 1892. Pentamerus, R. Etheridge, Jr. Pentameridae of New South Wales; Records Geol. Survey N. S. W., vol. iii, pt. 3, p. 52, pi. xi, figs. 5-9. (4) 1892. Pentainerus, Whiteaves. Contributions to Canadian Palaeontology, vol. i, p. 290. The elongate, subequally biconvex pentameroids being restricted to the divisions above discussed, there remains to be considered the large group of galeatiform shells which are characterized by their usually small size, inequal convexity, and deep, overarching pedicle-valve. A typical representative of this variable and undoubtedly heterogeneous group is the well-known Atrypa {Pentamerus) galeata, Dalman. These are the fossils embraced in UE Verneuil's grouping as " Pentamerus avec sinus," all having a median sinus more or less strongly developed. Two divisions of the first order may be based upon the position of this sinus, namely, those having it (1) on the pedicle-valve, and (2) on the brachial valve. In the former division belong such species as P. fornicatus, Hall, and P. Areyi, sp. nov., of the Clinton group; P. linguifer, Sow- erby, and P. ventricosus, Hall, of the later Silurian, as well as shells which have been referred to the Devonian subgenus, Pentamerella {P. arata, Conrad, P. dubia, Hall, etc.). With the latter division we may place P. galeatus, Dalman, P. nuc- leus, P. pseudogaleatus, Hall, P. (Sieberella) Sieberi, von Buch, etc , of the Silurian, and the various species of the subgenus Gypidula (G. comis, Owen, G. l(zviuscula, Hall, G. Romingeri, sp. nov.). This grouping might form a very convenient arrangement of these species, were the field clear of generic terms, but in each group designations of unequal value have been introduced, based upon varia- tions in other respects than contour alone. The Devonian members of each group develop with more or less distinctness a striated cardinal area and small and convex deltidial plates, with some accompanying variation in the character BRACHIOPODA. 243 of the internal septal plates. These divisions will ])e considered more at length. (A). Galeatiform peniameroids bearing the fold on the brachial valve and the sinus on the pedicle-valve. Among the Silurian shells of this group there are two types of exterior, one plicated {P.fornicatus, P. Areyi, of the Clinton group), and the other smooth (P. linguifer, P. ventricosus, of the Wenlock-Niagara). Tiiere is, however, little Fig. 173. Fio. nt. Fig. 173. Pentamerus { Barranddla) linguifer. Transverse section near the anterior extremitj- nf tlio median sep- tum in tlie pedicle-valve; showing the form of the spondylia. Ic.) Fig. 174. Pentamerus {Barrandetla) JSarrandii, Billings- A transvers"? section in front of the termination of the median septum of the pedicle-valve; showing the form of the spondylium in both valves, and the coalescence of the septa in the (lower) brachial valve. (c.) if any difference in internal structure. Davidson has shown* that P. linguifer bears a short spondylium in the pedicle-valve, supported only at its posterior surface, the free extension being produced forward and upward into the cavity of the opposite valve ; and, also, that the crural plates of the brachial valve are convergent. The accompanying transverse section of this shell shows that these plates are concave on their outer surfaces and are supported by conver- gent septa uniting as they reach the valve and leaving but a single median line of union on its surface. With very slight variation in the degree of conver- gence of the last-named plates the same structure exists in the P. ventricosus, of the Niagara dolomites, a shell whose differences from P. linguifer it may be difficult to establish.! In the strongly plicated Clinton species, P. Areyi, the internal structure varies in having, so far as known, a well developed spon- * Silurian Brachiopoda, pi. xvii, fig. 14 6. t This remark refers to the normally smooth shell which served as the type of the species. There is, however, a variation closely associated with P. ventricosus, both structurally and in its occurrence, which has low plications on fold and sinus, though the lateral slopes are smooth. Figures of this form are given on Plate LXXI. 244 PALEONTOLOGY OF NEW YORK. dylium in the brachial valve supported by a single axial septum. Pentamerus fornicatus is a small shell with a few broad, obscure plications, the most con- spicuous lying in the sinus of the pedicle-valve. The whole expression of its exterior is very similar to P. Barrandii, Billings, from the Anticosti series, though the latter is an elongate and much larger shell, interesting in having the sinus and fold, in immature growth-stages, on pedicle- and brachial valves respectively, but reversing this arrangement at maturity. This reversion is, however, to some extent illusory and need not affect the association of the species with P. fornicatus ; it is essentially due to the plication in the sinus of the immature pedicle-valve, which, after middle growth, fills up, and entirely obliterates the sinus itself; the effect in the mature shell being intensified by the corresponding development of the axial furrow on the immature fold of the opposite valve. A peculiar internal character of all these shells is the series of strong vascular, or ovarian sinuses, which radiate from the umbonal region of the pedicle-valve. These are complicated with the undefined diductor scars and are therefore to a certain extent of muscular origin. In Pentamerus fornicatus these are highly developed and produce strong ridges on the casts of the valve; while in P. ventricosus they are more numerous and much finer. In P. linguifer the character of the inner surface of the valves has not been described, but in transverse sections we find evidence that these sinuses were highly developed. It was for similarly ridged internal casts that Barrande proposed the generic term Clorinda (C. armata, Etage G, type ; C. ancillans, Etage E), both his species being pentameroids which in external form were probably not unlike P. linguifer. No name has been introduced which can be appropriately employed as a designation for this group of species typified by Pentamerus linguifer, Sowerby. QLhlert* has given to the term Antirhynchonella, Quenstedt, 1871, a value which would justify its use in this case were it not that the French author has evidently misinterpreted the original application of this name, which was inci- dentally suggested for such pentameroids as have the position of the median * Fisohbr's Manuel de Conchy liologie, p. 1311. BRACHIOPODA. 245 fold and sinus the reverse of that in Rhynchonella.* It is therefore proposed to designate them by the term Barrandella. The term Pentamerella, Hall (1867), embraces, in a broad sense, the Devo- nian representatives of the same type of exterior, though the latter present some structural differences. The shells are of larger size than those of Barrandella and strongly plicate, possessing a very narrow cardinal area, an elongate pseudo-area, and incipient deltidial plates. The median septum on the interior of the pedicle-valve is very short, and at times is altogether absent. In the brachial valve the crural plates and supporting septa form a distinct spondylium which is broadly sessile on the surface of the valve. The typical form of this division is the Atrypa arata, Conrad, a shell which abounds in the Schoharie grit and Corniferous limestone, and with it have been associated these other Devonian species: P. Pavilionensis, Hall,f of the Hamilton group, P. dubia, Hall, P. micula and P. obsolescens, Hall, from the middle Devonian faunas of Iowa. All of these shells have the ovarian surface of the pedicle- valve strongly pitted. (B). Galeatiform pentameroids having the fold on the pedick-valve and the sinus on the brachial valve. Here we meet with a nearly parallel development to that observed among the Barrandellas and Pentamerellas. In external character there is a greater uniformity as the shells are almost invariably plicated and the typical contour is subjected to but very slight variation. The Silurian shells which pass under the name of Pentamerm galeatus, Dalman, have a very considerable "^ Petiefactenkuinie Deutschlanda ; Biachiopoden, p. 231. The term as here employed is simply, the " Antirhynchonella-," but in the index (p. 727) the Latin form of the name is used. If any species can be taken as typical of Antikhtnchonella, it is the ConchicUum teimistriatus, Walmstedt, mentioned in imme- diate connection with the sinijle use of this name, and noi{Pentamerus linguifer, which is cited by Quexstedt as an illustration of the fact that the position of fold and sinus in the pentamei-oids is sometimes the same as in the Rhynchonellas. Antikhynchonella if adopted would be simply synonymous with CoxCHiDinM. t It is often difficult to make a satisfactory distinction between the Hamilton shell and P. arata. The latter is quite variable, the typical form from the grits and limestones having' rather broad ami shallow valves and comparatively few, strongly dichotomous ribs. Specimens from the grits are frequently much larger, sometimes very arcuate and tinely i-ibbed. The form prevailing in the Hamilton shales has fewer and more simple ribs and is rarely so large as P. arata. By a typographical error in the original desci-ip- tion of this shell the name has come into use as P. 'papillcmensi.t. We take this opportunity of coi'i-ecting it to Pavilionen.'iis, the current form being meaningless. 246 PALEONTOLOGY OF NEW YORK. development of the median septum of the pedicle-valve, while the spondylium is moderately long, and is free for fully two-thirds its length. In the brachial valve of typical examples from the Gotland and Wenlock limestones no spon- dylium is formed ; the septa supporting the crural plates resting directly on the Fig. 175. Fig. 176. Fig. 175. Trnnsveiso section of Peniamerus {Sieberella) galeatua, near the beaks, the pedicle valve Ijeing uppermost; allowing the discrete septa of tlie brachial valve. {c.) Fig. 176. Pentamerus (Sieberella) Sieberi, von Buch. Transverse section, showing the form of the spondylia. (C.) surface of the valves. To what extent the latter feature varies among the European Silurian specimens of this species we do not know, but in the American representatives of this type of structure, the variability in devel- opment of these crural plates is very apparent, and confirms the opinion already expressed, that the union or independence of the septa of the brachial valve is not a feature of generic importance. There are two American shells which are currently referred to this species ; the one from the Lower Helderberg fauna of New York has the closest similarity to the English shells in all points of structure, and in this one the septa in question invariably remain independent. A smaller shell also occurs in the Upper Silurian fauna of Perry county, Tennessee, which derives its name from an early identification by the late Professor Ferdinand Roemer.* In this shell, however, these septa appear to be frequently, if not invariably, convergent, forming a spondylium resting upon a median septum. In view of this and similar evidence which has already been cited, it seems impossible to follow OEhlert, who has proposed to restrict, under the generic name Sieberella,| shells of this type in which these plates are united and supported. This name has been based upon the species P. Sieberi, von Buch, a shell which abounds in the Bohemian Etage FJ and in the Hercyn- * Die Silurische Fauna des westlichen Tennessee, p. 73, pi. v, fig. 11. t In Pischer'.s Manuel de Conchy liologie, p. 1311. 1887. t Barrandb, Syst^me Silurien, vol. v, pis. xxi, Ixxvii-lxxix, cxviii, cxix. BRACHIOPODA. 247 ian of the Hartz Mountains,* resembling P. galeatus in contour though some- what shorter and more sharply costated. If the significance of this variability be restricted to a specific or even more subordinate value, we shall have a group of Silurian shells essentially equivalent to Barrandella, comprising such species as P. galeatus, P. Roemeri, nom. propos. (= P. galeatus, Roemer, op. cit.), P. nucleus. Hall, P. u?iiplicatus, Nettelroth, P. Sieberi, von Buch. All these shells are without evidence of cardinal area or deltidial plates, have the plication of the surface more strongly developed upon fold and sinus, and agree in the internal structure of the pedicle-valve. As the designation Sieberella has been brought into use for one of these species, we may take the liberty of broadening its significance by basing it upon more stable characters than those selected by its author, and applying the term to all shells of this type of structure, taking no account of the specific variability in the internal structure of the brachial valve. Typical Swedish and English Silurian specimens of Pentamerus (Sieberella) galeatus possess a peculiar surface sculpture consisting of very fine, irregularly anastomosing concentric lines, and, in rare instances, a similar character is pre- served in the Lower Helderberg specimens of the same species. In regard to the various shells from the Devonian that are referred to P. galeatus by the European palasontologists, it may be suggested that they are less likely to represent this specific type than to indicate the presence, in those faunas, of shells referable to the Devonian genus Gypidula. This group Gypidula, Hall, 1867, includes those galeatiform shells of the second division which have a well-defined, true, cross-striated cardinal area, and narrow, but erect or convex, incip- ient deltidial plates. On the interior the teeth are unusually strong, the septum of the pedicle-valve very short, the spondylium being free for most „ , ,P'^'JV' ■ ,-. r %^ o PentameriLS [Gypidula) comis, Owen, of its length. In the opposite valve a ..■ansver.o section in front or the short me.lian septum ..r o r r the peihcle-valve; showing the form ol the spondyha. the dental sockets are distinct, the "'•' crural plates expanded nearly horizontally, being divided at their beginning * Kayser, Abhaudl. zur geol. Specialkarte von Preussen, etc., Band 2, heft 4, p. 156, pi. xxvii, figs. 1-9, 13. 1878. 248 PALEONTOLOGY OF NEW YORK. by a narrow median cardinal process. The inner moiety of the crural plates is deflected to a vertical or slightly divergent position, and in this form they are produced anteriorly. These plates rest upon two broadly convergent septa which unite with the valve making a sessile spondylium, wliich is acute at its anterior extremity, and lies at, or in front of the center of the valve. The character of this structure in the brachial valve is not variable in Gypidula. The typical species of this genus is the Pentamerus occidentalis ( = P. comis, Owen), from the middle Devonian of Iowa, a shell whicli is usually more or less plicate, though these plications constantly show a tendency to obsolescence. With it are to be associated the G. IcEvhiscula, Hall, a small, smooth species, G. mundula, Calvin, also from the Iowa Devonian, G. subglobosa, Meek and Wor- then, from the Hamilton fauna at Rock Island, Illinois; G. Romingeri, sp. nov., a large, strongly plicate shell from the Hamilton fauna at Alpena, Michigan, and G. Lotis, Walcott, from the " Upper Devonian, on the Avest side of Applegate Canon, White Pine Mining District, Nevada."* The type was not one of long duration, and appears to be altogether absent from the New York faunas. Genus CAPELLINIA.f gen. nov. PLATE I.XX. Shells large, elongate subovate ; the relative size and convexity of the valves, normal for Pentamerus, are here reversed, the brachial valve being the larger and deeper, with full, strongly arcuate and incurved umbo and beak, the apex of which is concealed within the delthyrium of the opposite valve. The pedicle-valve has an acute suberect beak which is not arched posteriorly, but rises directly from the cardinal margins. Below it is a broad delthyrium with- out evidence of deltidial plates ; there is no hinge-line, but the margins of the delthyrium make subacute angles with the lateral margins of the valve. Car- dinal slopes very broad and abrupt. The surface of the pedicle-valve is flat- tened above, while that of the brachial valve is evenly and deeply convex ; it also shows a tendency to trilobation or obscure radial plication. The arrange- * Palfeontology of the Eureka District, p. 161, pi. iii, fig-. 9. t Dedicated to Cav. Giovanni Capellini, Pi-ofessor in Bologna and Senator of tiie Kingdom of Italy ; iu recog-idtion of his scientific achievements, and in gi-atefu! recollection of a personal friendship of many years. BRACHIOPODA. 249 ment of the internal septa and spondylium is the same as in Penfamerus oblcmgus, except that the supporting septa of the brachial valve are higher and more nearly vertical. Type, Capellinia mira, sp. nov. Niagara dolomites of Wisconsin. Observations. This remarkable shell is virtually a Pentamerus oblongm in which the relative convexity of the valves is reversed and this reversion car- ried to a great extreme. The single species observed, which has not before been described, has been studied from a number of examples obtained from the dolomites of Niagara age, in the vicinity of Milwaukee, Wisconsin, and loaned for study and use in the preparation of this volume by T. A. Greene, Esq., of that city. It has not been observed elsewhere. These reversed shells have afibrded no evidence that a normal relation of the valves existed in early growth-stages, and in this respect they differ from the reversed shells of the genus Anastrophia. Genus STRICKLANDINIA, Billings. (1863)1859. PLATE LXXin. 1839. Spirifer Atrypa, J. de C. Sowerby. Silurian System, pi. xxi, figs 3, 21; i)l. xxii, fig. 6. 1846. Spirifer, McCoy. Silurian Fos?ils of Ireland, p. 37, pi. iii, fig-. 24. 184S. Spirifer, de Vernedil. Bull. See. Geo!. France, second ser., vol. v, p. 347. 1852. Spirifer. H.^ll. Palaeontology of N. Y., vol. ii, p. 66, pi. xxii, fig. 3. 1859. PeiitamiruK, Salter. Murchison's Siluria, .second ed., pp. 100, 230, figs. 1, 3. 18.59. Stricklandia, Billings. Canadian Naturalist and Geologist, vol. iv, p. 132-135. 1861. Stricklandia, Billing.s. CanaI. xi, fig. 14. 1864. .* Rensselwria, Davidson. Monogr. British Devonian Braehiopoda, p. 10, pi. iv, figs. 5-7. 1870. Rejisselwria, Dall. American Journal of Conchology, vol. vi, p. 105. 1874. Rensselmrla, Billings. Palseozoic Fossils, vol. ii, p. 41, pi. iii, tigs. 7, 10. 1876. Rensselasria, F. Roemee. Lethtea Palaeozoica, pi. xxiii, fig. 5. 1882. ? Rensselmria, David.so.v. Suppl. Devonian Braehiopoda, p. 19, pi. i, figs. 20, 20 a. Diagnosis. Shell oval or elongate-ovate in outline, subovoid in contour, broadest posteriorly ; valves unequally convex, with a more or less distinct median elevation on both. Cardinal slopes broadly flattened in the typical species. Lateral margins compressed and often strongly intlectted. Pedicle-valve with tuU, scarcely salient umbo; beak acute, incurved, with terminal foramen. Beneath and on each side of the beak is a concave, sharply defined space, but no proper cardinal area. Distinct deltidial plates divided by a median suture may be present, but they are usually concealed by incurvature, or atrophied by the encroachment of the umbo of the opposite valve. On the interior the teeth are prominent but not thickened, widely divergent and close within the margins of the valve. They are supported by stout dental plates which rest for most of their length upon the bottom of the valve, but are free along their posterior margins. These plates are closely appressed against the lateral walls of the shell and become coalescent therewith in later growth-stages. The muscular impression is restricted to the posterior portion of the valve, covering a very narrow longitudinal area. Between the dental plates at the bottom of the pedicle-cavity lies a narrow median scar, and in front of this a very deep, elongate impression which is sometimes clearly divided into central adductor scars embraced by the diductor impressions. This distinc- 256 PALEONTOLOGY OF NEW YORK. tiou is usually lost, and only a median division by a slight longitudinal septum is discernible. The entire area does not extend more than one-third the whole length of the valve. Over the post-lateral slopes are numerous line, irregularly ramifying genital sinuses. The brachial valve is considerably the less convex and is often flattened. The beak is minute and usually obscured by the overlapping pedicle-valve. The hinge-plate is large, fiat, triangular, sometimes thin, often thickened on its posterior portion and resting on the bottom of the valve. It is separated from the lateral shell-walls by narrow dental grooves widening at their extremities. Normally this plate appears to have been perforated by a visceral foramen entering at the underside and opening at or beneath the apex of the beak. This perforation is however frequently filled by adventitious deposits though traces of it are discernible in the oldest shells, and in casts of the interior the filling of the tube is often preserved. Tlie median portion of the plate, lying between two vertical supporting lamellse resting on the bottom of the valve, is preserved in the earliest and simpler species, but in the larger and later forms of the genus, is frequently resorbed, giving the plate the appearance of being composed of subtriangular, discrete lateral halves. The crura are the continuation of the upper portions of the supporting septa. Neither these nor the rest of the brachidium have been seen in the type species, R. ovoides, of the Oriskany sandstone,* but in R. Marylandica, the crura are broadened just beyond their base of attachment, and from their upper angles are given off the jugal processes which are long, pointing upward and inward, but not uniting. From the lower angles the descending arms take their origin, following the curves of the valve, diverging for a short distance, thence abruptly approaching, and uniting to form a broad elongate, acutely triangular plate, which is not supported by a median septum, or otherwise connected with the valve. From the middle of the posterior margin of the plate arises a small rod-like process, which extends for a short distance upward toward the crura. The entire length of the brachidium is nearly two-thirds that of the valve. *The tigufes of the brachial supiiorts ascribed to R. ovoides in the Twelfth Report on the Slate Cabinet of Natural History, p. 41, repiesent the siiecies -S. Marylandica, which at that ilate had not been sejiarated from R. ovoides. BRACHIOPODA. 257 The muscular area is less cleai'ly delimited than that of the opposite valve, and its component scars are not often distinctly defined. It is, however, broader and longer than on the pedicle-valve, and is divided transversely into anterior and posterior adductor scars, the former being the larger, and their surface cov- ered by branching lines radiating from a median longitudinal ridge. From the narrow and somewhat elevated posterior extremities of this area extends a broad median sinus, on either side of which arises a stout vascular trunk bending backward and over the post-lateral slopes. Secondary branches are given oflF from both its margins. These vascular markings of the genital region are rarely well defined. Surface of the shell distinctly plicated, with sparse concentric wrinkles near the anterior margin. The radial lines may be fine or coarse, but no species is known in which the surface is entirely smooth.* Shell-substance punctated beneath the epidermal layer. Type, Terebratula ovoides, Eaton. Oriskany sandstone. Observations. The discussion of the genus Amphigenia has given occasion to notice its close resemblance in form and various structural details to the typical Renssel^ria, or properly, to the Rensselgerias most closely associated with that genus in time. The existence of a spondylium in the one, and of a terebratuloid brachidium in the other, are the distinctive differences in the two groups. A considerable number of species has been referred to the genus Rens- seLjEria, but it seems necessary to remove some of them to other genera on account of significant structural differences; and among those which remain to Renssel^ria in this somewhat restricted sense, there are still some variations of a chronological or developmental value. In the type species, R. ovoides, we are dealing with a shell in which size, form and structural features have been carried beyond the normal mature or acmic stage of phyletic devel- opment. This becomes evident from a comparison with the earlier species *The species R. IcBvis, Hall, from tlie Sliiily limestone of the Lower Heldeibei-g gioiip, was described as having- a smooth exterior, and should this pioVe to be the fact the shell will probably prove not to belong to this genus. Its interior is still unknown. 258 PALEONTOLOGY OF NEW YORK. occurring in the Shaly limestone of tlie Lower Helderberg group, R. aquiradiata, Conrad, R. elliptica, Hall, R. mutabilis, Hall, in all of which the form is tere- bratuloid, the umbonal slopes very gradual, not full and squared, the beak of the pedicle-valve prominent and suberect, exposing the undisturbed deltidial plates ; while the muscular scars are but feebly developed. Similar characters are shown in R. Cumberlandicz, of the Oriskany fauna at Cumberland, Maryland, where pre- dominating species of this formation are associated with many Lower Helderberg types. In R. Cayuga, sp. nov., of the later Oriskany of Ontario, the elongate- oval form of the shell is maintained with close incurvature of the beaks and inci'eased convexity of the brachial valve. The high-shouldered form and linguate outline of R. ovoides, which it shares with Amphigenia, is also well exemplified in R. Marylandica. In the structure of its brachidium, Renssel^eria is very similar to Centro- NELLA. This similarity has been frequently noticed and has been brought out with especial emphasis by ^hlert in his demonstration of the brachial supports of Te.rebratula Guerangeri, de Verneuil,* though we can not follow this author in his reference of such plicated shells to the genus Centronella. This genus bears upon the surface of the broad anterior plate a median ridge which projects a little at each extremity ; in C. Julia, A. Winchell, this ridge becomes a promi- nent vertical plate. There is, however, in these shells no posterior and upward projection of the ridge, as in Renssel^ria. In the earlier and smaller forms of RensseljERIA, the hinge-plate is thin and perforated by an oval foramen which lies below the apex of the umbo. It is also distinctly divided by diverging ridges at whose extremities originate the crura. This structure is precisely that of T. Guerangeri, and in respect to the brachidium throughout there is no material difference except in the lesser development of the anterior plate in the latter. Rensselceria mutabilis, Hall, of the Lower Helderberg fauna, which is the smallest known representative of the genus, frequently exhibits a primitive condition of the brachidium in the imperfect coalescence of the lateral parts of the anterior plate and the development of a median ridge upon its lower side. * Note sui- Terebratula (Ceiiti'iinella) Guerangeri ; Bull, de la Soc. d'Etudes Scientif. d'Angers, 1883, pp. 1-11, pis. i, ii. BRACHIOPODA. 259 These features, which are shown in the figures herewith given, are accompanied by a correspondingly primitive expression of the exterior, the form of the shell being terebratuloid with the usual oblique cardinal slopes and regularly everted i'JG. 178. Via. 179. Loop of Iienssel(e7-ia miitnhilis. Hall. Fig. 178. View from above; sliowinc; the perforatetl hinge- i)late anil the'sim()le irregular line of coalescence of the lateral processes. Fig. 179. View from in front; showin,? the iipwanl curvature of the anterior plate and the nieilian rifjgc on its under surface. (c.) Of the species which have been referred to RENSSELyEiiiA, R. Suessana, Hall, from the Oriskany fauna of Maryland, and also known in the lower Oriskany of the Hudson River valley, presents difference.-^ in form and structure suffi- cient to render its association with R. ovoides unnatural and unsatisfactory. These shells are lentiform in general contour ; moderately and subequally con- vex ; both valves with an obscure and undefined median fold. The beak of the pedicle-valve is prominent, never incurved sufficiently to conceal its deltidial plates and foramen. The cardinal margin beneath the beak is flattened into a well-defined pseudarea, and the short inflection of the margin beginning here is continued along the lateral portion of the shell, where it meets a similar marginal inflexion from the opposite valve. These produce the sharp introver- sion of the lateral margins which is also one of the characteristics of the genus Megalanteris. The surface of the valves is covered with fine, hair-like radiating striae, which often are visible only near the margins or at their thickened extremi- ties on the inflexed portions of the shell. On the interior the dental lamellae are short and do not rest upon the valve. The hinge-plate is supported by two vertical septa, the median cleft and visce- ral foramen are more or less obscured and with sometimes a bilobed callus in 260 PALEONTOLOGY OF NEW YORK. its place. The brachidiuni haw long, straight jugal processes, the triangular anterior plate in numerous specimens shows that the posterior rod-like process from the median ridge of that plate extends upward almost to the crura, but terminates abruptly and has no connexion whatever with the latter. To dis- tinguish this peculiar modification of the RENSSEL^RiA-type, it is proposed to adopt the subgeneric term, Beachia.* Rensselczria Suessana, so far as now known, is its only representative. With our present knowledge the genus Renssel^ria must be recognized as the earliest and most primitive type of terebratuloid structure. That this genus, and Centronella, together with the plicated group of Terebratula Guer- angeri, and perhaps also, the plicated shells incompletely described by Waagen as NoTOTHYRis, from the Permo-Carboniferous limestones, have had a common origin must be regarded as beyond a reasonable doubt. The simple loop in all of these forms is but the result of the coalescence of the two lateral arms or extended crural processes ; and anything more simple than the triangular loop of Renssel^eria would be only the discrete processes of Amphigenia and the rhynchonelloids. Renssel^ria appeared with the Lower Helderberg fauna and, in America, disappeared with the Oriskany sandstone. The Terebrafula strigiceps, F. Roemer, from the lower Devonian of Siegenf has been referred to this genus by Kayser, and though the internal charactei s of this species have not been demonstrated, its exterior endorses this interpretation. Elsewhere in Europe the existence of RENSSELiERiA has not been satisfactorily established. *It is with great satisfaction that I dedicate this iiilei'esting- g-eiieric form to the Hon. Allen CJ. Bbach, of Watertown, N. Y., an earnest advocate and patron of science, who, while Lieutenant-Governor of the State in 1870, recognized the importance of estalilishing the State Cabinet of Natural History as an organization for the promotion of scientific- reseai'ch, as intended by its founders, and, with the aid of a few friends, secui-ed the enactment of a law organizing the institution as the "State Museum of Natural History." The purpose of this law was to carry into efl'ect the i-eccmmendation of the Legislature of 1866 : — to place that organization "ui the condition required by the present state of science, and to maintain it in full efficiency as a Museum of Scientific and Practical Geology and Comparative Zoology." In this connection I recall with pleasure the interest taken in this matter by Hon. William F. Allen, at that time State Compti-oUer, and afterwanls Judge of the Court of Appeals, who drew the form of this bill and aideil in securing its passage by the Legislature. t See also Quenstedt, Petrefactenk. Deutschlands ; Brachiopoden, p. 343. 1871. BRACHIOPODA. 201 Genus NEWBERRIA, Hall. 1891.* PLATE LXXVIII. 1867. Reiixxelccyia, Meek. Ti-ans. Chicag-o Acad. Sci., voL i, pt. i, p. 108, pi. viii, tif,'. 8 ; pL xiv, i\g. 4. 1867. RmsselcBHai Hall. Paheontology of New York, vol. iv, p. 385, pi. IviiiA, fig.s. 9-20. 1883. RensselcBria, Cl.\ypole. Prnc. American Philosophical Society, p. 235. 1891. Newberria, (Hall) Whitkaves. Contributions to Canadian Pal.-eontolofry, vol. i, pt. 3, p. 237, pi. XXX, figs. 3, 4, 4 a. 1S91. Newherrin, Hall. Tonth Ann. Rept. N. Y. State Geologist, pp. 91-99, pis. v, vi. Diagnosis. Shell elongate-ovoid, having the general contour and external aspect of RENSSELiERiA and Amphigenia, but without the strongly radiate-striate surface prevailing in the former genus, and less strongly developed in the lat- ter. The greatest convexity of the valves is in the umbonal region, or above the middle of their length, and in some forms the surface is distinctly flattened over the lateral slopes, leaving the median portion of the valves very promi- nent and sometimes subangular. The cardinal and lateral margins are regular, even and not inflected. The pedicle-valve has the rostrum produced and incurved, the apex slightly truncated by the subcircular foramen ; deltidial plates small and obscure. The teeth are comparatively small, projecting forward and gently upward, free at their extremities, and supported by narrow dental plates which join the bottom of the valve above the middle of its length and are continued forward as slender, widely divergent ridges upon the inner surface, gradually merging into the shell. In the bottom of the rostral and umbonal cavity is a broad, usually ill- defined muscular area, from which radiates a series of vascular ridges and depressions extending into the marginal region of the valve. The diductor scars are situated posteriorly and deeply impressed ; between and in front of them is a narrow, elongate adductor scar which is rarely divided medially and often extends forward to, or beyond the center of the>alve. On each side of the muscular impression is a thickened area, very narrow at its origin in the * On account of similarity to Renssbl.«ria in exterior form and external shell-markings, the discussion of Newberria is introduced here, though we are still in ignorance of the structure of its brachial appaiatus. Furthei- consideration of the Rens.seljeria brachidium and its vai-iations is given with the observations on CBNTROlfELLA and Its allies, immediately following. 262 PALEONTOLOGY OF NEW YORK. rostral region or pedicle-cavity, and produced into divergent ridges, usually two on each side, and a fifth in the median axis. These may extend to the mar- gins or disappear before reaching the middle of the valve and are variously subdivided by vascular grooves and sinuses emanating from them. In the brachial valve the hinge-plate is small, similar to that of Rens- SELiERiA and Amphigenia in general form, but is of relatively less size than in the former genus and is not perforated by a visceral foramen opening beneath the apex. Two veiy narrow, almost linear and closely submarginal dental sockets extend nearly to the apex ; within them lie two broad, subtriangular crural plates, which are divided by a triangular median fissure extending to the bottom of the valve. The inner anterior angles of these plates bear the slender crural processes, the extent of which is unknown. In mature individ- uals the apical portion of the hinge-plate is peculiarly constructed ; the lateral areas become more or less completely united, without altogether obliterating the median triangular fissure, and above this point the surface is excavated into a spoon-shaped cavity, when the development is extreme, or is trans- versely angular in the average individual. At a short distance from the hinge-plate and in the bottom of the valve there arises a low median ridge, which continues for a short distance, separating the obovate, narrowly flabelli- form scars of the anterior and posterior adductor muscles. The anterior scars are considerably the larger, and their surface is longitudinally striated. The vascular grooves and ridges are more obscurely developed than in the pedicle- valve. Surface smooth or covered with fine concentric striae accompanied by stronger wrinkles of growth. The inner lamims are sometimes marked by obscure radiating striae near the margins of the valves. Shell-substance finely punctate. Type, Renssel(zria ? Johannis, Hall. Hamilton group. Observations. Several of the earlier species of Renssel^eria have an essen- tially similar form to the representatives of this genus. This, however, is not the broad-shouldered form of R. ovoides nor of Amphigenia, and none have BRACHIOPODA. 263 radiating surface striae of the latter shells. In Amphigenia the high dental lamellae bounding the muscular impressions of the pedicle-valve are supported by a median septum ; in RENSSELiERiA and Megalanteris this supporting septum is wanting, the convergent lamellge resting on the bottom of the valve. In Newberria, however, these lamellae are exceedingly divergent and quite short ; the muscular impressions being sunk in the shell without other delimitation. In typical forms of Renssel^ria, as well as of Amphigenia, the hinge-plate is not deeply divided medially, and is perforated by a visceral foramen, though the latter is frequently closed. In Newberria there is no evidence of this perfora- tion. The peculiar apical structure of the hinge-plate has been made out from internal casts of the best known species, N. Claypolii, Hall, and, upon com- paring with these the description and figures of Megalanteris inornata {Atrypa inornata, d'Orbigny), given by CEhlert,* the latter clearly evince a similar structure. The strong development of the sinuses in Newberria is a feature of distinction. In the allied genera Renssel^ria, Amphigenia and Megalan- teris, the sinuses are more or less clearly defined in the umbonal region and about the area of muscular insertion, but in Newberria the great trunk vessels originate about the ante-lateral edges of the muscles and traverse the brachial region, while the posterior surfaces of the valves are free of them. The distinctive differences in this type of structure from Renssel^ria were indicated in the Fourth Volume of the Palaeontology of New York, where the species there described as Rensselizria ? Johannis was referred to that genus with doubt and a suggestion incidentally made that a new generic division might, with further knowledge, be erected for it.f This fossil was from the beds of the Hamilton group, at Waterloo, Iowa. There was also known at that time, in the collections of Professor G. C. Swallow, then State Geologist of Missouri, a larger form possessing similar characteristics, from the Hamilton rocks of Moniteau county, Missouri, which has since been described as Newberria Missouri- ensis, (Swallow) Hall.J * Annales des Sciences Geologiques, vol. xix, art. No. 1, p. 20, jil. ii, figs. 1-10. t The term Rensselandia was there used in this incidental manner, but as it was not defined and etymologically is without meaning, it can not be adopted. t Tenth Report of the New York State Geologist, p. 97, pi. v, figs. 10-12. 1891. 264 PALEONTOLOGY OF NEW YORK. With our present knowledge there may also be included in the same group, the species described by Meek, from the McKenzie river, as Rensselaria lavis* and more recently identified by Whiteaves, in the same region, associated with Stringoccphalus Burtini, and other characteristic middle Devonian species ; and also the interesting and abundant form discovered by Professor E. W. Claypole in the sandstones of the age of the Hamilton group, in Perry county, Pennsyl- vania,! subsequently described as Newberria ClaypoUi. This shell occurs in great quantities both at the locality cited, and in a coarser pebbly sandstone at Pine Grove, Schuylkill county, in the same State, a locality which has furnished most instructive specimens of both the interior and exterior of the shell. There can be little reason to doubt that (Ehlert's Megalanteris inornata (d'Orbigny sp.), to which reference has already been made, represents this genus in the Devonian of western France. The agreement is found both in the detailed structure of the hinge-plate, the arrangement of the muscular areas and the character of the vascular sinuses. In default of other evidence, it may be considered probable that the Atnjpa Deshayesi, Caillaud, A. amygdala, d'Orbigny, and Terebratula amygdalina, Goldfuss (Kayser), from the lower and middle Devonian of France and Germany, also represent the genus Newberria. This genus seems to be a later modification of the RENSSEL^RiA-type of brachi- opod structure. The true Renssel.eria, so far as known, closed its existence, in America at least, with the disappearance of the fauna of the Oriskany sand- stone. Amphigenia is not known in the faunas succeeding those of the Upper Helderberg, while Newberria occurs in the lower and middle Devonian, Hamil- ton group, and is probably not of earlier age. *Not RensselCBria Iwois, Hall, Pal. N. Y., vol. iii, p. 256. 1859. t See Proceedings of the American Philosophical Society, p. 235. 1883. BRACHIOPODA. 265 Genera (1) CENTRONELLA, Billings, 1859; (2) ORISKANIA, GEN. NOV. ; (3) S E L E N E L L A , gen. nov. ; (4) ROMINGERINA, GEN. NOV.; (5) TRIGERIA, Bayle, 1875; (6) NOTOTHYRIS, Waagen, 1882. PLATES L, LXXVI, LXXIX. (S) 18-11. Terehratula, Phillips. Palieoz. Foss. Cornwall, Devon and West Soiner.set, p. 91, pi. xxxv, tig. 167. (1) 1867. R!iy7whoneUa, Hall Tenth Ann. Rept. N. Y. State Cab. Nat Hist., p. 124, figs. 1-6. (1) 1859. Centronella, Billings, ('anadian Natnralist and Geolcigist, vol. iv, p. 131, tigs. 1-5. (5) 1860. Rhyuchospira, Hall. Tbii-leenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 83. (1) 1861. Centronella, Billings. Canadian Journal, vol. vi, p. 271, tig. 97; p. 272, tigs. 98, 99. (1) 1861. C'CTitnweZte, Hall. Fourteenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 102. (1) 1862. Centronella, Hall. Fifteenth Ann. Rept. N. Y. State Cab. Nat. Hist., pi. iii. figs. 1-5. (1) 1862. Centronella, Billisgs. Canadian Naturalist and Geologist, vol. vii, p. 392. (4) 1862. Centronella, A. Winchell. Proc. Acad. Nat. Sci. Philadeljihia, vol. vii, p. 405. (5) 1862. Rensselmria, Billings. Pi-oc. Portland Soc. Nat. Hist., vol. i, p. 115, jilate, fig. 12. (6) 1862. Terebratida, Davidson. Quarterly Journal Geological Society, vol. xviii, p. 27, pi. ii, fig. 4. (1) 1863. Centronella, Hall. Sixteenth Ann. Rept. N. Y. St.ate Cab Nat. Hist., pp. 45-47, figs. 13-17. (1) 1863. Centronella, ll.>i.i,h. American Journal of Science, vol. xxxv, p. 402. (1) 1863. Centronella, Billings. Amei-ican Journal of Science, vol. xxxvi, p. 236. (1) 1863. Ce7jJ?-07te/Za, Billings. Geology of Canada, p. 374, figs. 403-405. (4) 1863. Cryptonella, Hall. Sixteenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 41-43. (4) 1863. Cryptondla, Hall. American JournaFof Science, vol. xxxv, pp. 399-402. (6) 1863. Terehratula, de Koninck. Foss. Paleoz. de I'lnde. p. 32, pi. ix, fig. 4. (I)? 1865. Centronella, A. Winciibll. Pi-oc. Acad. Nat. Sci. Philadelphia, vol. ix, jip. 122, 123. (1) 1867. Centro7iella, Hall. Pal.TontoIogy of New York, vol. iv, pp. 399-403, 420, pi. Ixi A, tigs. 1-40. (3) 1867. Centronella, Hall. Palaeontology of New York, vol. iv, p. 419. j.l. Ixi a, tigs. 47-49. (4) 1867. Centronella, Hall. Palseontology of New York, vol. iv, p. 419, pi. Ixi A, figs. 41-45. (5) 1867. Centronella, Hall. Palfeontology of New York. vol. iv, p. 276, p!. xlv, figs. 1-6. (1)? 1870. Centronella, A. Wincuell. Proc. American Philosophical Society, vol. xii, p. 254. (5) 1875. Trigeria, Bayle. Rxplic. de la Carte Gc'olog. de France, Atlas, pi. xiii, figs. 5-12.-, (6) 1878. Tei-ebratula, Abich. Geolog. Forsch. in der Kaukasisch. Landern, I, p. 68, pi. vi, fig. 10. (5) 1882. Centronella, Davidson. British Devonian Brachiopoda, Suppl., p. 14, pi. i, figs. 7-9. (6) 1882, Nototfiyris, W A AiiEH. Productus limestone Fossils ; Brachiopoda, pp. 375-390, pi. xxviii, tigs. 1-13; pi. XXX, tigs. 13, 14. (5) 1SS3. Centronella, CEhlkkt. Bull, de la Soc. d'Etudes Scientif. d'Angers, pp. 1-11, pi. i, figs. 1-1 1; pi. ii. figs. 1-6. (5) 1885. Centronella, CEulert. Bull, de la Societe d'Etudes Scientif. d'Angers, pp. 1-5, plate, figs. 1-19. (1) 1888. Centronella, Herrick. Bull. Denison University, vol. iii, p. 49, pi. ii, tig. 5. (1) 1889. Centronella, Nettelroth. Kentucky Fossil Shells, p 153, pi. xxxi, figs. 14-17. (5) ? 1890. Centronella (.*), Derby. Archivos do Museu Nacional do Rio de Janerio, vol. ix, p. 84. (6) ? 1890. Notothyris (.*), Derby. Archivos do Museu Nacional do Rio de Janeiro, vol. ix, p. 81. (2) 1892. Centronella, Beechek and Clarke. American Journal of Science, vol. xliv, p. 414. In discussing the genus Renssel^eria and its subgenus Beachia, it has been observed that these shells combine a plicated or striated exterior with a brach- idium constructed upon the same type as that of Centronella, Billings. 266 PALEONTOLOGY OF NEW YORK. The latter genus was established in the same year (1859) as Renssel^eria, and was founded upon a small plano-convex species with smooth exterior, the Rhynchonella glans-fagea, Hall, from the Upper Helderberg group. The original description and figures illustrative of this genus did not give the structure of the brachidium with accuracy, but this was afterwards made out by Dr. Carl Rominger and shown in his excellent figure, given in the Sixteenth Report on the New York State Cabinet of Natural History (p. 47, 1863), and which is reproduced in this place. Subsequent examinations have endorsed the correctness of Rominger's determination and also show that the type upon which it is constructed is the same as in Renssel^ria ; the actual differences of expression appearing (1) in the shortness of the jugal processes, (2) in the less extended anterior plate, and (3) in the prominent median crest or ridge upon that plate, not produced posteriorly into a rod-like apophysis. It has already been observed that in the early (Lower Helderberg) species of Renssel^eria, such as R. mutabilis, some of these features, as the length of the crura, and the development of the median process are not so advanced as in the later and typical species of the genus, nor as in R. (Beachia) Suessana. Upon farther examination of more extensive material it is found that this type of brachidium-structure has, without essential variation in itself, been associated in Devonian faunas with a considerable variety of external form and ornamentation of the shell. This fact has already been observed by some authors. Reference has been made to CEhlert's observation* of a similar brachidium, with a perforated hinge-plate, in certain small plano-convex or biconvex plicated or ribbed species, Terehratula Guerangeri, Centronella Bergeroni and C. Gaudryi, from the Devonian of western France, all of which he has referred to Centronella on the basis of this structure. Derby has found a brachidium of similar structure, though somewhat more nearly approaching that of Renssel^ria, in another small and strongly ribbed biconvex species from the Devonian of the State of Matto Grosso, Brazil, described by him under the name Centronella ? Margarida.f *BuU. de la Soc. d'Etudes Scientif. d'Angers, 1883, pp. l-ll, pi. i, figs. ]-ll; pi. ii, figs. 1-6; ditto, 1885, pp. 1-5, plate, fig.s. 1-19. t NotS sobi-e a Geologia e Paleontologia de Matto Grosso : Archives do Museu Nacional do Rio de Jan- eiro, vol. iv, p. 84, figures. 1890. BRACHIOPODA. 2G7 In the Devonian of North America we find species externally similar to Terebratula Guerangeri, and shall presently recur to tliem in considering the precise variation of structure which such forms exemplify. Further, there is evidence of the existence, in the Upper Helderberg fauna, of a small, smooth biconvex terebratuliform shell, with sloping cardinal margins which bears the same form of brachidium as Centroiiella glans-fagea* This type of brachial apparatus, however different may be the exterior of the shells bearing it, whether ribbed, striated or smooth, biconvex or plano- convex, has a definite time-value, and our present knowledge indicates that, beginning its existence in the Lower Helderberg, it is continued into the Oris- kany sandstone, Upper Helderberg and Hamilton groups without material modification. From this time onward the structure yielded to modifying influences. In the Centronella Julia of A. Winchell, a smooth, biconvex species from the Mar- shall group of Michigan, at the base of the Lower Carboniferous series, the anterior triangular plate of the brachidium bears a high vertical lamella extend- ing in both directions beyond the limits of tluit plate into the cavity of the pedicle-valve. Such forms must be kept apart from the earlier and typical Centronellas, as indicative of a progressed stage of development. The strongly plicated shells from the Productus limestone (Carboniferous) of the Salt-Range of India, which Waagen has described under the generic name Notothvris (though the struct- ure of their brachidia is not fully known), will undoubtedly prove to possess some modification of the Crntronella type. Such a modification is evident in Derby's Notothyris ? Smithi {loc. at.) from the Devonian, a similarly plicated species which may prove to be an ancestral form of the Carboniferous Notothyris. Returning again to the genus Centronella and restricting our conception to forms similar to that regarded by its author as typical, the following diag- nosis may be deduced : * Farther I'eference will be made to this shell. 268 PALEONTOLOGY OF NEW YORK. Shells plano-convex or concavo-convex. Pedicle-valve with acute incurved beak, perforated at its extremity, the foramen being continuous with a partially closed delthyrium; medially ridged, and with abruptly sloping sides. On the interior the teeth are large, thick at their extremities and adherent to the lateral walls of the shell. Between them is a deep pedicle-cavity, in the bottom of which lie the elongate scars of the adductor muscles, and about their ante- rior portion the small, flabellate diductors. The brachial valve is very shallow, rendered concave exteriorly by a median sinus which does not make itself apparent on the interior. Beak small, apex not incurved. Dental sockets broad, bounded interiorly by the high walls of the hinge-plate. This plate is divided medially by a deep furrow extending to the apex, and therefore consists of two processes which are elevated, thickened and rest on the bottom of the valve. From the anterior face of these arise the crura which converge for a short distance, and expand to form two broad acute jugal processes. From here the lateral branches of the brachidium curve outward, gradually turning from a vertical to a horizontal position, broaden rapidly and unite to no. iso. Centronella glans/agea. Hall. form an anterior triangular plate which bears a ^ prepaiatioa showing the brachidium. median ridge, where the two lateral branches are 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, Rhynchonella glans-fagea, Hall. Upper Helderberg group. Observations. The type 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 different 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. Fig. 181, Fic;. 183. Fig. IS'i. Oriskania navicella, sp. nov. Fig. 181. .V cardinal view; showing the hing:e-pl.'xtc .iml the elevation of the narrow median crest or cardinal pro- cess. The specimen also retains tlie teeth of the pedicle-vaUe and a jiortiou of the dental lamellae, 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 e.\tent of the cardinal process. Fig 183. A profile of the same specimen; showing the thickness of the plate and the uncinate form of the cardinal process. X .'!, (c.) Such an extravagant modification of the normal form of the hinge-plate in Renssel^ria 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 liut. of great size." Beecher and Clarke. Notice of a new lower Oriskaay fauna in Columbia county, New York; Amer. Journal of Science, vol. xliv, p. 414. 1S92. 270 PALEONTOLOGY 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 RENSSELiERiA and Centronella ; the anterior plate broader and less attenuate than in RENSSELiERiA 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. 184. Fi<;. ISS. Selenella gracilis, sp. nov. Fig. 184. Outline prollle of conjoineil v.^lves. Fife'. 186. Preparation sliowinft the I'orm of the loop. Fig. 18B. An oblique view; showing Ihe upward curvature of the anterior plate. X 3. FlO. 186. (C.) classed with that genus, e. g., Centronella Julia. From such of these whose inte- riors are known it diifers notably, and it so evidently indicates a distinct stadium * See BiTTNER, Bi^aehiopodeii del- Alpiiien Trias; Abhandl. der K.-k. Geol. Reichstanst., vol. xiv, p. 208. 1S90. 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 pre'sents the first combination of the smooth, biconvex valves with an unmodified RENSSELiERiA-CENTRONEi.LA 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, FIG. 187. FIG. 188. JRomingerina Julia, Winchell. Fig. 187. A restoration of the loop; showing the extent of the meilian pl.ite. Fi". 188. A profile view; showing the elevation of this plate, the double curvature of its upper margin and its fim- briated edge. X4. (A. WiNCUELL.) 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 species fi-nm the Chemung- samistones at Rushfonl, N. Y., which has been iiienlifieii by Williams as CentroneUa Julia (Bull. U. S. Geol. Survey, No. 41, p. 56. 1887), has the brachidium of similar structure though with a less ante-posterior extension of the verlical plate. 272 PALEONTOLOGY OF NEW YORK. " The upper edge where viewed from_the side, is flatly roof-shaped, while the lower edge describes two convexities, the greater anterior, leaving a notch between them. The surfaces of the loop and median plate are covered with minute, obliquely conical pustules, in some cases seeming to become spinulous."* Forms with this characteristic modification of the loop may be designated by the term Romingerina.j 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 Juvavella. Their brachidia 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 Qj]hlert, 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- seljERIa, 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 Rhynchospira, Tre- matospira and Zygospira. The brachidium has been isolated in none of these, but sections demonstrate that this structure in all these forms is similar to that * Pi-oc. Acad. Nat. Sci. Philadelphia, p. 405. 1S62. t Dr. Cakl Romingeb, to whom this genus is dedicated, was the tiist American investi{,''ator who suc- ceeded in producing satisfactoi-y translucent preparations of the fo.ssil brachiopods with calcitied bi-aohidia. Many of the determinations published in the Reports on the New York State Cabinet from 1861-67, and in Volume IV of the Paleontology of New York, as there recognized, were 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. \ ¥11 ilM/ Fl(i. 189. TrigerUi Guerangeri, de Verneuil. The interior of t!ie brachial valve; showing tlio iierlorated hinge-plate and the muscular scars. (CEhlert.) CEhlert draws attention to the fact that Bayle, in 1875,* applied the name Trigeria to two lower Devonian species, the first, the Terebralula 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. Gaudnji; indeed, upon careful comparison with Dr. GEhlert'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 Rensselczria Portlandica,f 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. I For the opportunity of examining the original specimens of the species we are indebted to Professor B. K. Emerson, of Amherst College. 274 PALEONTOLOGY OF NEW YORK. Derby's Centronella ? 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 Erer6 fauna on the A.mazonas, a species which is suggestive of the Rhynchospira lepida, Hall, of the Hamilton fauna of New York. Dr. Dekby 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^ria, 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. ISO. Fig. 191. Notothyris subvescicularis, Davidson. FIG. 192. Fig. 190. A dorsal view of the exterior. Fig. 191. A proQIe of the saraesliell. Fig. 192. Tlie interior of tlie brachial valve; showing the perforated hinge-plate and the lateral lamellse 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 plicated species made by the Rev. Noeman Glass, and given by Davidson, Devonian Brachiopoda, Suppl , 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 brachidium 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 {Terebraiula subvescicularis, 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 Diel.\sma 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 SCAPHIOCCELIA, Whitfield. 1891. 1891. Scaphiocixlia, Whitfield. Trans. Ainei'ican Inst. Mining; Eng-ineer.^, 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, Scaphiocalia 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 terra 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. FIG. 195. Fig. 196. ScaphioccElia BoHviensis, VVhitflekl Figa. 193-196. Views of two individuals, showing the external characters of the species. . (Whitfield.) BRACHIOPODA. 277 Genus MEGALANTERIS, Suess. 1855. PLATE LXXVII. 1830. Terelnatula, de Verneuil. Bull. Sr c. G60I. jle France, 2 ser., vol. vii, p. 17.'>, pi. iv, %. 2. 1855. Megmiteris, Sues.s. Ueber Meganteris ; Sitzungsbev. (lev Kais. Acad, der Wissen.sch. zu Wieii. 1856. Mugantms, iSusss. Cla.ssitication der Brachiopoden, von Th. David.son, p. 43, pi. ii, fig. 18. 18.o7. MegaJdorix, Hall. Tenth Ann. Kept N. Y. State Cab. Nat. Hist., p. 101. 1859. Jienssilcerla, Hall. Palaeontology of New York, vol. iii, p. 458, pi. cvi, tijf. 2o-/. 1861. lioissclceria, McChesney. Descr. New Fossils from Palaeozoic Rocks of West. Stales, p. 85. 1867. Rensselmrla, McChesnet. Trans. Chicago Acad. Sciences, vol. i, p. 36, pi. vii, figs. 2a-c. 1868. Renxselmria, Meek and Worthen. Geological Survey of Illinois, vol. iii, p. 401, pi. viii, figs. 4 a, b. 1871. Meganteris, Quenstedt. Petrefactenkunde Deutschlands ; Brachiopoden, p. 344, pi. xlvii, figs. 21, 22. 1876. Meganteris, F. Roemer. Lethoea Pala=ozoica, j)!. xxiii, iig. 6. 1887. Megalavtcris, (Ehlert. Fischer's Manuel de Condiyliologie, p. I3I!1. 1891. Ntwbeniaf, 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. Sliells 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 RENSSELiERiA in exter- nal form, that the possession by them of a brachidium 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-j^late is swollen into a callous uncinate process, which is subcubical, and on its surface bears two small V-shaped ridges for the 278 PALEONTOLOGY 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 Fig. 197. FIG. 193. Megalanteris Archiaci, de Vcrneuil. Figs. 197, 19S. Views of the exterior of the species. (De VEENEnlL.) 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 Fig. 199. Fig. 200. Megalanteris Arckiaci, de Verneail. Figs. 199, 200, A restoration of the br.achial apparatus. (SlTESS.) BRACHIOPODA. 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. FIG. 201. Fig. 202. ' Megalanteris Archiaci, de Verneuil. Fig. 201. An internal cast of the umbon.il region of tlie pedicle-valve. (SuESB.) Fig. 202. The interior of the umbonal region of the brachial valve; showing the cardinal process. (DE Vekneuil.) " 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 PALAEONTOLOGY 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 brachidium, we find the other characters of the shell suffici- ently distinct from those of Renssel^eria and its allies ; and these difierential 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 (Plethorhynchus), 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 f as Mega.nteris ovalis, Hall, but which has been subsequently and currently referred to RENsSELiERiA. 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 Rensselaria Condnni, of * Internal casts fi-equently show a minutely radiate surface about the margins, but this structure prob- ably beloiig-s to the inner laniinie of the shell. t Tenth Annual Report on the Condition of the N. Y. Stale Cabinet of Natural History, p. 101. 1857. BRACHIOPODA. 281 McChesney. None of the specimens that have been sectioned retain tlie bra- chial apparatus. The name Meganteris or Megalanteris* has been adopted by various writers, sometimes with questionable accuracy. Megalanteris Archiad, 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. Qdenstedt 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 (EHLERT,f 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. Kayser has suggestedt the similarity of the Terebratula amygdalina, Goldfuss, to Megalanteris, and ^hlert, 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, liaving 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 (Ehlbrt, in 1887. t Annales des Sciences Geologiques. vol. xix, p. 20, pt. ii, fig-s. 1-10. J Zeitschr. der deutsch. geolog. Gesellsch., vol. xxiii, p. 499. 1871. § Paime du Calcaire d'Erbray, p. liil, pi. x, figs. 5, 6. 1887. 282 PALEONTOLOGY OF NEW YORK. Genus STRINGOCEPHALUS, Defrance. 1827. (emend. Sandberger. 1842.) 1827. StrygocejiJialux, Defrance. Diction, des Sciences Nat., vol. li, p. 102, Atlas jil. Ixxv, figs. 1, 1«. 1827. Terebratula, SowBRBY. Mineral Concholofry, pi. dlxxvi, fig-. 1. 1834. Ttrehratula, voN Bdch. Ueber Teiebrateln, p. 117. 1SS9. Striyoccpliahts, Sowerby. Trans. Geol. Soc. London, vol. v, second ser., pi. Ivi, figs. 10, 11. 1840. Strygocephalus, D'AiiCuiAC and de Veknbdil. Trans. Geol. Soc. London, vol. vi, 2 ser., p. 393. 1841. Strigocepliaius, Phillif.s. Palaeoz. Foss. Coi-nwall, Devon and West Somerset, p. 79, fig. 141. 1842. Strinyoce2)}ialiis, Sandberger. Leonhard und Bi'oini's Jabrbuch, p. 386. 18E0. Strhigocephalus, F. Roemer. Beiti'. zur Kenntn. des nordw. Harzgeb., p. 24, pi. x, fig. 2. 1852. Uncites, McCoy. Bi'itish Pala-oz. Foss., p. 380, pi. ii A, fig. 6. 1853. Stringoceplialus, Schndk. Beschreib. Eifel. Bi'achiopoden, p. 195, pi. xxviii, fig. 5; ]il. xxix, fig. 1 ; pi. xxxi, fig. 1. 1850. Slrigocephalns, KiNti. Permian Fossils, p. 70, pi. xix, fig. 1. 1853. Stringocephalus, Sukss. Verb, der zool. bot. Vereins zu Wien, vol. iii. 1855. StringocepJialus, Thb Sandbergers. Verst. -e- 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 difFereno.e 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, Macandrewia 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 5 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 RensseljEria 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 pi'esence 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 PALEONTOLOGY OF NEW YORK. septum in these Devonian and Carboniferous terebratuloids gives a greater sim- plicity to the variations of the loop in different stages of growth, though their final condition is the same. Cryptonella ranges upward into the early faunas of the Carboniferous period ; well defined internal casts of a large form like the full-grown examples of C. planirostra, occur in the Waverly group of Ohio, and it seems probable that the Centromlla Alii, A. Winchell, described from the Marshall group of Michigan, will prove to be a Cryptonella. Accompanying precisely the same structure of hinge-plate as that just described is a variation in the form of the brachidium presented by several of the Devonian species which have usually been referred to Terebratula, namely, T. Sullivanti, T. Harmonia, Hall, of the Corniferous limestone, T. simulator and T. Lincklani, Hall, of the Hamilton group. The 'brachidium, compared with that of the normal Cryptonella, is quite short, extending less than one-half the length of the brachial valve, and the recurvature of the ascending branches exceedingly slight. This recurved lamella is so delicate that it is rarely completely preserved, but when retained the entire brachidium has the form represented in the adjoining figure. The crural apophyses are situated more Fig. 209. Fig. 210. Fig. 209. Terebratula [Eunella] simulator, Hall; showing the character of the liinge-platc, the relative length and usual proservatiiin of the brachidium, with the ascending band lost. Fig. 210. Terebratula'iiEunella) Sullivanti, Hall; a dorsal view of the complete brachidium. anteriorly than in Cryptonella and are much broader at the base. It would be hardly justifiable to include these species in the same group with typical forms of Cryptonella, and hence, to forms having this type of brachidium, it is proposed to apply the term Eunella. BRACHIOPODA. 291 In the Carboniferous limestone of Windsor, Nova Scotia, we find a very inter- esting form, in the species described as Centronella Anna, Hartt,* where tlie long and greatly recurved Cryptonella brachidium is retained with some accompany- ing modifications in other features. It seems, beyond doubt, that Professor Hartt misapprehended the structure of the brachidium in the shell. He has represented it as somewhat similar to that of Centronella Julia, A. Winchell, the descending branches uniting anteriorly to form a vertical median plate. By good fortune there has been obtained an example of this rare shell, filled with compact crystalline calcite, a most unusual condition of preservation in this limestone ; and the demonstration of the brachidium from this specimen is very complete. The external form of the shell is unusual, being plano-convex or naviculoid, as in the typical species of the genus Centronella ; the brachial valve is depressed-convex or nearly flat and the pedicle-valve medially ridged with abrupt slopes at the sides. The dental lamellaj of the pedicle-valve are well developed as in Cryptonella. In the brachial valve there is a short, tripartite hinge-plate, supported by a median septum of considerable height in the um- bonal region and extends for fully one-half the length of the valve, becoming low anteriorly. The crura are very short and are continued almost immediately into the long convergent crural apophyses The descending branches of the brachidium extend for nearly the entire length of the shell, following the curvature of the valve and approaching each other anteriorly, their extremities being again directed outward. The ascending branches extend backward to points not far in front of the crural apophyses, where they are united by a transverse band. The outer margins of the descending lamelljB are fringed with rather long, irregularly set spinules directed toward the commissure of the valves. There are no spinules elsewhere on the brachidium. Although we are not inclined to place a high value upon the presence of these spinules, they seem to be, in many cases, a natural accompaniment of the brachidium in late palaeozoic species (see observations on Athyris); but the entire combination of the centronellid * Hartt in Dawson'.s Acadian Geology, second ed., \>. 300, fig-. 90. 1868. 292 PALEONTOLOGY OF NEW YORK. contour of the shell, highly developed median septum, with the fimbriated descending branches of the brachidium, warrants the separation of this type Fig. 211. Fig. 212. Centronella (Barttina) Anna, Hall. Dorsal aut-l pioiile. views ol" a prepaiatioii of the bracliiiliuiii; bhowing the binge-plate, broaii jugal procesijea, lim- briated descending lamellae, long recurved lanielloe, and prominent median septum in the brachial valve. (0.) of structure from other known genera, from which it may be distinguished by the term Harttina. A Carboniferous species, Waldheimia Coutinhoana, with an essentially similar internal structure, has been described by Derby * from the Amazonas. This shell is rather more biconvex than Harttina Anna, and has a lesser develop- ment of the dorsal septum ; together, they represent the continuance of the CRYPTONELLA-type of brachidium into the later palaeozoic faunas. * Bulletin iif the Cornell University, vol. i, No. 2, p. 3, pi. iii, tig. 22; pi. viii, fig. 6; pi. ix, tigs. 1, 2. 1874. BRACHIOPODA. 293 Genus D IE L ASM A, King. 1859. PLATE LXXXt. 1809. Conchyliolithus ammiites, Mabtjs. Petrefacta Derbiensia, p. II. 1816. Terebratulites, Schlotheim. Denkschr. der K. Akad. der Wissensch. zu Munchen, vol. vi, p. 27. 1824. Terebratula, Sowkrby. Mineral Conchology, vol. v, p. 65. 1824. Terebratula, von Bdch. Ueber Terebi-ateln, p. 90. 1836. TerebratMla, Morton. American Journal of Science, vol. xxix, p. 150, pi. ii, fig-. 4. 1844. Atrypa, McCoy. Synopsis Carb. Foss. Ireland, p. 153. 1845. Terebratala, de Vernedii,. Geol. de la Russie et des Mont, de I'Oural, vol. ii, pp. 63, 65, pi. ix, figs. 7, 8. 1848. Terebratula, Geinitz. Verstein. der deutsch. Zechst. Gebirg., p. 11, pi. iv, figs. 27-36. 1850. E'pithyris, King. Monog-i-. Permian Foss. England, p. 146, pi. vi, tigs. 40-45. 1854. Terebratula, Semenow. Die Fo.ss. des schles. Kohlenk., p. 11, pi. iii, tig. 5. 1855. Seminula. McCoy. British Paljeozoic Fossils, p. 408. 1856. Terebratula, Hall. Pacific R. R Reports, vol. iii, p 101, pi. ii, figs. 1, 2. 1857. Terebratula, Davidson. British Permian Brachiopoda, pp. 3-11, pi. i, figs. 5-22; pi ii, tig. 2. 1857. Terebratula, Davidson. British Carboniferous Brachiopoda, pp. 11-16, pi. i, figs. 1-lG, 23-32; pi. ii, figs. 1-8. 1858. Terebratula, Hall. Ti-ansactions of the Albany Institute, vol. iv, pp 6, 7, 35. 1858. Terebratula, Hall. Geology of Iowa, vol. i, pt. ii, p. 711. 1859. Dielasma, King. Pi'Oc. Dublin Univ. Bot. Zool. Assoc , vol. i, p. 260. 1859. Tenh-atula, Meek and Hayden. Proc. Acad. Nat. Sci. Philadelphia, vol. iii, secoaid ser., p. 26. 1859. Terebratula, Shdmard. Ti-ans. St. Louis Acad. Sci., vol. i, p. 392. 1860. Terebratula. White. Jour. Boston Soc. Nat. Hist., vol. vii, p. 228. 1861. Terebratula, McChbsney. New Palseozoic Fossils, p. 82. 1861. Terebratula, Geinitz. Dyas , p. 82, pi. v, figs. 14-28. 1863. Terebratula, Hall. Sixteenth Ann. Kept. N. Y. State Cab. Nat. Hist., p. 48. 1863. Terebratula, Davidson. Quart. Jour. Geolog. Soc. London, vol. xix, p. 169, pi. ix, tigs. 1-3. 1863. Terebratula, Swallow. Trans. St. Louis Acad. Sci., vol. ii, p. 83. 1867. Terebratula, Hall. PaL-eontology of New York, vol. iv, p. 389, pi. Ix, tigs. 17-25, 66, 67. 1868. Terebratula, White and St. John. Trans. Chicago Acad. Sci., vol. i, p. 119. 1869. Terebratula, McChesney. Ti-ans. Chicago Acad. Sci., vol. i. p. 37, pi. i, fig. 2. 1869. Terebratula, Toula. Sitz. der Kais. Akad. der Wissensch zu Wien, vol. lix, p. 1, pi. i, fig. 1. 1871. Terebratula, Qdenstbdt. Petrefactenkunde Deutschlands ; Brachiopoden, pp. 427, 429, pi. Ii, figs. 1-9. 1873. Cryptonella, Hall and Whitfield. Twenty-third Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 225, 229. 1872. Terebi-atula, Meek. Sixth Ann. Rept. N. Y. S. Geol. Survey Terr., p. 470. 1873. Tei-ebratula, Meek and Wortuen. Geol. Survey of Illinois, vol. v, p. 572, pi. xxv, tig. 15. 1874. Terebratula, Derby. Bull. Cornell University, vol. i, pp. 1, 63, jil. ii, tigs. 1, 3, 8, 16; pi. iii, fig. 24 ; pi. vi, fig. 15. 1875. Terebratula (Dielasma), White. Wheeler's Expl. and Survey West 100th Mend., vol. iv, pp. 93, 144, pi. xi, tig. 10. 1878. Terebratula, Dawson. Acadian Geology, third ed., p. 287, tig. 87. 1880. Terebratula, Davidson. British Cai-boniferous Brachiopoda, Suppl., ji. 269, pi. xxx, tig. 7. 1882. Terelrratula, Whitfield. Bull. American Mus. Nat. Hist., vol. i, pp. 54, 55, pi. vi, figs. 53-64. 1882. Terebratula, White. Eleventh Rept. State Geol. Indiana, p. 361, pi. xxxix, figs. 6-8. 1882. Dielasma, Waagen. Productus-liniestone Fossils ; Brachiopoda, jip. 336-359, pis. xxv, xxvii. 1883. Terebratula, Hall. Twelfth Rept. State Geol. Indiana, pp. 336, 337, pi. xxix, figs. 53-64. 294 PALEONTOLOGY OF NEW YORK. 1884. Tertbratida, White. Thii-teenlh Kept. State (ieol. liuiiaiia, p. 137, jil. xxxii, figs. 17-19. 1884. Terelrratnla, Walcott. Monogr. U. S. Geol. Survey, vol; viii, p. 224. 1884. Dielasma, Davidson. Bi'itish Fossil Bi'achiopoda; General Summary, p. 411. 1887. Dielasma, de Konince. Faune du Calcaire CarboniKi-e de la Belgique, pp. 5-31, pis. i-viii. 18S9. Terehratula, Nettelroth. Kentucky Fossil Shells, v. 155, pi. xvi, figs. 20-22. 1890. Terehratula {Cryptonella}, Calvin. Bull. Lab. Nat. Hist. Stale Univ. Iowa, p. 174, pi. 3, iig. 4. 1893. Didasma, Beecher and Schuchert. Proc. Biol. Soc. Washington, vol. viii, pp. 71-78, pi. x. Some years before the introduction of this term its distinguished author had applied Phillips' name, Epithyris, to certain Permian species {Terebratulites elon- gatus, Schlotheim, type) which he found to differ from Teeebratula, in the sense in which the term was then current, in their " prominent dental plates and trans- versely semi-elliptical moderately recurved loop." Epithyris, as used by Phillips, has no significance as a generic term ; whatever value it might have was thus given it by King, but the author subsequently decided to discard the term and introduce a new one, Dielasma. The name has not been widely adopted, though this fact appears to have come, less from any objection to, or insufficiency in, the distinctive characters of the division, than to a general disposition to leave all the terebratuloid shells of the Palaeozoic with the old genus, Terehratula. Waagen has recognized the value of this genus and the usual facility with which its species may be recognized. It is not, however, upon the characters given by King that we can rely for the distinction of Dielasma from the other palaeozoic terebratuloids. In external form, the convexity of both valves is generally well developed, and the outline is usually elongate-oval. But in both of these respects there is very considerable variation ; the development of a median sinus on both valves with a plication and groove at the bottom of it, as in the Terehratula turgida, Hall, of the Chester limestone, and T. vescicularis, de Koninck, of the Coal Measures, produces a form at once suggestive of the typical biplicate Terebratula of the Jurassic age. A general depression of the pedi- cle-valve anterior to the umbo, and a corresponding elevation of the opposite valve, appearing first in the Cryptonella Calvini, Hall and Whitfield, of the mid- dle Devonian, is carried to an extreme in the T. bovidens, Morton, of the Coal Measures. The apex of the pedicle-valve is closely incurved, so that in adult shells but little remains of the deltidial plates. The foramen is large, quite generally BRACHIOPODA. 295 Fig 013. Dielasma boHdens, Morton. An enlargement of the umbonal portion of the brachial valve; showing the slightly thickened processes on eitlier sideof the beak. (c.) encroaching upon the umbo and often becoming very oblique to the longitudinal axis ; with the increase of this obliquity the deltidial plates are thickened in their inner surface, which thus becomes more or less protruded. The inverted sheath or collar within the foramen is highly developed and clearly shown on internal casts. On the interior the dental plates are conspicuous, as in Cryp- TONELLA, but they stand vertically upon the bottom of the valve, not showing the convergence and often actual union occurring in that genus. In the brachial valve the dental sockets are quite deep and narrow, the soc- ket-walls rising abruptly, though not attaining the height of the dental plates of the opposite valve. They are distinctly separated from the crural plates or margins of the hinge-plate, and converge toward the apex where they merge into a slightly ele- vated cardinal process ; the latter usually appear- ing as a crescentic submarginal wall, though when best preserved is seen to be composed of two lateral, somewhat rounded lobes. The crural plates are two divergent vertical lamellae, originating just below the cardinal process, and attaining a length equal to the distance between their extremities, which is about one-third the width of the valve at that point. Between these plates lies the long shallow hinge-plate, which is raised but little above the bottom of the valve, and is sometimes actually adherent to it. This plate attains its greatest width at the ex- tremities of the vertical crural plates, its margins converging thence ante- riorly, its full length often equaling one-third that of the valve. To this plate are attached all the muscles of the brachial valve, the scars of both anterior and posterior adductors being frequently clearly defined upon its surfoce. Upon comparison of this structure with that of Cryptonella the homologies are at once apparent, but there is a Fig. '211. Dielasma elongaium, Schlotheim. The interior of the umbonal region of the two valves; showing the highly developed dental plates (rf), the elon- gate, sessile hinge-plate with \l» muscular scars, and the form and mode of attachment of the brachidium. (Davidson.) 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 lamellas 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 lamellae 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.! It has been suggested by WaagenJ that the Terebratula Lincklani, Hall, of the Hamilton fauna of New York, might prove to be an early representative of Dielasma. Reasons have already been advanced to show that this species, with *Faune du Calcaire CarboniKre de la Belgique; Ann. du Mus N. Y. d'Hist. Nat. de Belg., vol. xiv, pt. vi, pp. 5-31, pis. i-viii. 1SS7. t Palseontologia Indica ; Productus-limestone Fossils, pp. 336-359, pis. xxv-xxvii. 1882. X.Op. cit., 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 Cryptonella. But there are other Devonian species in which the loop is far more like that of Dielasma, as for example the Terebratula Romingeri, 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. Terebratulai^Cranana) nommgeri, a&w. ,. , ,1 T 1 1 1 An oulline showing the Dielasma foim of the brachiiliuni divergent, the ascending branches ab- anathe,iivi,ie,ihinge-„iate. 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 about one-third that of the brachial valve. This peculiar structural variation may be designated by the term CRAN^ENA.f Probably uther American Devonian species, besides the two mentioned, will be found to belong to this group when satisftictory evidence of their internal structure has been obtained. Recent observations by Beecher and SchtjchertJ 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 Renssel^ria {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 * Calvin, Bull. Lab. State University of Iowa. p. 174, pi. iii, fig. 4. t To Miss Agne,s Crane, of Brig-hton, England, an associate in the latin- lalmrs, of Dr. Thomas David- son, and an astute student of the Brachiopoda. I Development of the Brachial Supports in Dielasma and Zygospira, op. cit. 18'ja. 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 FIG. 216. Fig. 217. Flu. 'ilS. Dielasma turgula, Hall. Fig. -JKi. The ceulrouelliloriu stage ol' the loop. X li. Fig. 217. A later stage; showing the resorption of the anterior portion of the loop. X G. Fig, 218. Early Dielas.ma stage, produced hy further resorption. X 6. Fig. 219. Loop and hinge-plate of a mature specimen. X G. FIG. 219. till near maturity. It is thus clearly demonstrated that the brachidiuni of DiELASMA and, inferentially, all similarly recurved loops are secondary modifica- tions of the primitive structure linding its mature expression in Renssel^eria and Centronella. DIELASMINA, Waagen. 1882. 1882. Dielasmhia, VVaaljen. Pi'oiiuctiis-liineatone Fossils ; Brachiopoda, p. 369, 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. FIO. 220. FIG 221. Dielasmina plicata, Waagen. Dorsal and frontal views. IWaagen.) They have the dental plates of the pedicle-valve and tlie general form of the brachidium in that genus, as for as the interior is now known, but for the BRACHIOPODA. 299 present the distinctive difference lies in the nature of the exterior. Tliis 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. Terebratula, Davidson. Quart. Joui-n. Geol. Soc. London, vol. xviii, p. 27, pi. ii, tig-. 1. 1863. Terebratula, de Koninck. Foss. Paleoz. de I'lnde, p. 32, pi. ix, fig. 1. 1878. Terebratula, Waagen. Records Geol. Surv. India, vol. ix, p. 186. 1882. Hemiptychina, Waagen. Productus-limestone Fossils; Brachiopoda, pp. Htil-375, pi. xxvi, figs. 6-10; pi. xxvii, figs. 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. SublcCVis, fig. 2-22. Bemiptychlna mmalayensu. Davidson. Wino-PTl Tbp nronrietv of including a portion of the interior; »howing the .ibsence of aental waagen. ine propriety 01 inoiuumg ^^^^^^ .^ ^^^ peaicle-valve, and the DiELASJiA-likc these plicated and smooth shells in the brachidium. (Waaoes.) 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 Himalaijensis, 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. Flc. 223. Seecheria [Hemiptychina) subtatis, Waageii. Dorsal view; showing the smooth exterior. (Waagen.) single form) of smooth species without dental plates. It is here proposed to separate these shells from Hemipty- china and to distinguish them by the term Beecheria,* giving a brief account of the interior structure as exemplified in B. Davidsoni, 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 lamellae 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. Fio. 224. Beecheria Davidsoni, Bp. nov. An enlarged profile oi" the brachidium; showing the man- ner in which lamellse arise from the bottom of the valve, the broad posterior jugal processes and the much nar- rower descending lamella. The anterior transverse or reflected band is not fully retained. (c ) Genus CRYPTACANTHIA, White and St. John. 1867. 1867. Waldheimia? (Cryptacanthia), White atid St. John. Trans. Chicago Academy of Sciences, vol. i, [it. i, p. 119, fig-. 3. Our knowledge of this genus is still very imperfect. The authors described as Waldheimia? compacta, a rather small, plano-convex or naviculoid shell from * In recognition of his important contributions to our knowledge of the Bi-achiopoda. t This is the shell identified by David.son as Terebratula saccidus, Martin. (On the Lower Carboniferous Brachiopoda of Nova Scotia; Quart. Journ. Geol. Soc, vol. xix, p. 169, pi. ix, tigs. 1-3, 1863.) BRACHIOPODA. 301 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 ) Fro. 225. Waldheimia^ [Cryptacanthia) compacta. White and St. John. A copy of the original liguro. (WHITE and ST. John.) 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 DiELASMA or Cran^ena. 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 Fig. 226. A fimbriated DiELASMA-lifce brachidium from the chert of the Burlington linie^itone. The mediiiD dotted lines indicate the position of the longi- tudinal band described as probably casual in origin. The outline 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 TROPIDOLEPTUS, Hall. 1857, PLATE LXXXU. 1839. Strophomena, Conrad. Ann. Kept. Geolog. Dept. N. Y., p. 64. 1847. Leptcena, dk Vebnbdil. BulL Soc. Geol. de France, second sei\, vol. iv, p. 705, pi. iii, figs. 7, 7 a. 1853. LejjicBna, Schnur. PalsBontog-i-aphica, vol. iii, p. 220, pL xl, tig. 2. 1856. Strophomena, The Sandbergbrs. Verstein. der ihein. Schichten-systems, p. 66, pL xxxiv, fiff. 8. 1857. Tropidoleptus, Hall. Tenth Ann. Kept. N. Y. State Cab. Nat. Hist., p. 151, figs. 1, 2. 1859. Tropidoleptus, Hall. Twelfth Ann. Kept. N. Y. State CaL. Nat. Hist., p. 31. 1865. Leptana? Davidson. British Devonian Brachiopoda, p. 87, pi. xvii, figs. 1-3. 1867. Tropidoleptus, Hall. Palaeontology of New York, vol. iv, p. 404, pi. ixi a, tigs. 50-52 ; \<\. Ixii, figs. 2a-c, Za-y. 1868. Tropidoleptus, Meek and Worthbn. Geology of Illinois, vol. iii, p. 427, pl. xiii, fig. 2. 1874. Tropidoleptus, Rathbon. Bull. Bufl'alo Soc. Nat. Sci., voL i, p. 254, pL ix, fig. 10. 1876. Tropidoleptus, Derby Bull. Mus. Harvard Coll., vol. iii. No. 12, p. 282. 1881. Tropidoleptus, Rathbdn. Proc. Boston Soc. Nat. Hist., vol. xx, p. 35. 1889. Tropidoleptus, Nettelroth. Kentucky Fossil Shells, p. 46, pl. xvii, figs. 14, 15. 1890. Tropidoleptus, Derby. Arch. Mus. Nac. de Rio de Janeiro, vol. ix, p. 76. 1892. Tropidoleptus, Ulrich. Paleoz. Verstein. aus Bolivien ; Neues Jahrb. filr Mineral., etc., Bei- lagebnd. viii, p. Ti, pl. iv, tifrs. 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 vfilve 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 al)out 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 PALEONTOLOGY OF NEW YORK. vergent, slender jugal processes are given off 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 parts. Type, Strophomena carinata, Conrad. Lower and middle Devonia)i. Observations. 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 leptsenoid genera. After the examination of a large amount .i^^^^^i-^-^ Fig. 227. Fig. 238. Tropidoleptus carinatus, ConiaJ. Fig. 2-27. The interior of the brachial valve; showiug the^cardiiial process, creuulateil ilental sockets, loop and raeiliau septum. Fig. 228. The same in profile; showing the height of the median septum and the mode ol" attachment of the lamella; 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 lamellae of the brachidiura witli the median septum in this shell is the earliest evidence and only known instance in palseozoic 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, Maqasella, Kraussina, Platiuia, BoucHARDiA, 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 tlms 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, sliowing only the primary completed calcification of the lateral branches or descending lamellag, and aflbrding 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 Muhlfeldtia 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, etc. 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 Terebratellidje. 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 Revision of the Families of the Loop-beaiing 13iachiopO(ln, by Charles E. Bkkchkk ; 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 Sirophomena or Leptcena 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 GEN ERA WHOSE SYSTEMATIC POSITION IS UNDETERMINED. Genus EICHWALDIA, Billings. 1858. PLATE LXXXni. 1848. Terebratula, Davidson. Bull. Soi\ Geol. de France, second sei-., vol. v, pi. iii, lig-. 34. 1849. Atrypa, d'Orbigny. Pi'odrome de Pal^ontologie, vol. i, p. 40. 1852. Ati-ypa, Hall. Palseontolofry of New York, vol. ii, p. 281, pi. Ivii, tig-a. :>a-t. 1858. Eichxoaldia, Billing.s. Rept. Geol. Survey Canada for 1857, p. litO, fig.s. 24 a-e. 1859. RhynchoneUa, Po7-amhoniU's, Salter. Muvchison's Siluria, second ed., pp. 250, 544. 1860. Poramhonltes, LindstrOm. Gotland's Brachiopoden, p. 364. 1863. RliynclwHella- Hall. Transactions of the Albany Institute, vol, iv, p. 217. 1866. EicJiwaUUa, Billings. Catalogue Silurian Foss. Anticosti, p. 10. 1867. Eicliwaldia, Dictyonella, Hall. Twentieth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 274-278, figs. 1-7. 1869. Eicliwaldia? Davidson. British Silurian Brachiopoda, p. 193, pi. xxv, figs. 12-15. 1875. EicJiwahUa, Hall. Twenty-eighth Ann. Rept. N. Y. State Mus. Nat. Hist., p. 159, |)1. xxvi, figs. 50-54. 1879. Eichwaldia, Barrande. Systeme Silurien du Centre de la Bohriue, vol. v, pi. Ixxxi. figs. I-III. 1880. Eichwaldvi, Lind.strom. Angelin's Fragmenta Silurica, p. 25, \\\. ii, figs. 16-20. 1883. Eichioaldia, David.son. British Silurian Brachiopoda, Suppl., p. 140, pi. viii, tigs. 15, 16. 1884. Eicliwaldia, David.son. British Fossil Brachiopoda, General Summary, p. 355. 1884. Eichioaldia, Young. Geological Magazine, vol. i, No. 5, p. 214. 1889. Eicliwaldia, Beecher and Clarke. Mem. N. Y. State Mu-!., vol. i. No. I, p. 31, pi. iii, figs. 11-13. These curious shells have been carefully studied by Billings, Hall, Davidson, LiNUSTROM 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, trianguliir 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 t'lii. 230. Fig. 229. Fig. 231. ■^^ .' Fig. 233 mwM Fig. 235. Fig. 233. Interior ol" Ijrachi.al valve. Fig. TU. Vertical section of shell. Fig. 235. Enlargement of the surface. Eickwaldia reticulata, lln]\. Fig. 229. Dorsal view. Fig. 230. Cardinal view. Fig. 231. Longitudinal section of the two valves. Fig. 232. Interior of pedicle-valve. Notation i f, " bare spot," foramen ? ; p(c), deltidium or internal plate; c', umbonal surface of pedicle-viilve; T, teeth; B, dental sockets; j, cardinal process; s, 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 ofEichwaldia Capewelli 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, FIG. 236. FIG. -237. Fl<;. 'JSS. FiG. 239. Pli:. 240. Eichwaldia Capeioelli, Davidson. Fig. 236. Hexagonal cells of the outer surface of tile shell in unwoi'U specimens. Fig. 237. Small polygonal cells in walls of hexagonal cells. Fig. 238. Polygonal cell layer between outer hexjigonal cells and inner dense layer. Fig. 239. Perforated inner dense layer. Fig. 240. Vertical section of the shell; a, outer hexagonal cell-walls; 6, polygonal cell layer; c, inner dense layer with minute jierfoi-ations. {YOUNG ) 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 * See Beecher and Clarke, Memoirs N. Y. State Museum, vol. i, No. 1, p. 32. t Bakrande, SystSme Silurien, vol. v, pi. Ixxxi, %s. 1, 2; Beechek and Clarke, oj). cit., pi. iii, fig-- 11. 310 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 Fig. 241. Fig. Hi. Eichwaldia suhtrigonalis, Billing-s. Dorsal and ventral views of a silicified young shell retaining the pedicle; showing its protrusion from the unibona aperture. From photographs of the original specimen described by Btllings. original illustrations of the type-species, E. suhtrigonalis, 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. suhtrigonalis, 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- hosa 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 Lindstrom, in the Island of Gotland. Barrande has illustrated three species from the stages 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. 18o4. dionetes? Semenow. Zeitschr. iler deutsch. g-eolog-. Gesellschaft, vol. vi, p. 34.^, pi. v, fig-s. ia-d. 1862. ChnnHes, Davidson. British Carboniferous Brachiopoda, p. 278, pi. !v, tig-. 13. 1871. Aulaeorhynchus, Dittmak. Ueberein nenes Brachiopoden-Geschlecht ausdem Berg-kalk ; Verb. d. k. Akad. d. Wissensch. St. Petersburg, second ser., vol. vii, p. 1, pi. i. 1870. ChonetesJ? Meek and Worthes. Proc. Acad. Nat. Sci. Philadelphia, p. 3u. 1873. Isogmmma, Meek and Wokthbn. Geological Survey of Illinois, vol. v, \>. 56S, \,\. xxv, figs. 3a-d. 1882. Aalacorhynehiis, Barroi.s. Reeherches sur les Terrains anciens des Asturies et de la Gallice, p. 326, pi. xvi, figs. &a-d. 1884. Aulacorhynchus, Davidson. British Fossil Brachiopoda ; Appendix to Supplements, ]>. 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 nii-dian 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 bracliial 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 PALAEONTOLOGY 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 EiCHWALDiA. 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 Choneles concenirica, 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 Aulacorhynchus 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. 1S78. Baiirynium, Waagen. Rei:oi-ds Geol. Sui-v. India, vol. xi, pp. ISfi, 187. 1880. Thecidea, Zugmayer. Unters. iiber ihat. Brachiopoden ; Beitr. ziir Palaon. von Oesterreich- Ungai-n, I, ji. 22. 1882. Leptodns, Kayseh. Richthofen's China, vol. iv, p. 161. 1883. Lyttonia, Waagen. Pi-odnctua-Iimestone Fossils; Brachiopoda, [ip. 396-40S, pi. xxix, figs. 1-3; pi. XXX, figs. 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. Fi(j. '.'43. Fk;. 244. Lyttonia nobilis, Waagen. Fig. 243. Cardinal part of a poilicle-valve; showing the hinge-line, median and lateral septa. Fig. 244, A portion of the interior of a brachial valve. (WAAGEN.) 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. Genus OLDHAMINA, Waagen. 1883. 1863. Bdlerophon, de Koninck. Quart. Jour. Geol. Soc. London, vol. xix, p. 8. 1880. Thecidea, ZuiiMAYER. Untei'S. iibei' rhat. Brachiopoileii ; Beitr. /iir Palaout. Oesten-eich- Unjrarn, I, p. 22. 1883. Oldhamina, Waaobn. Productus-limestone Fossils; Brachiopoda, pp. 403-409, pi. xxxi, iigs. 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. f Via. 216. Fig, 245. riG. 217. Oldhamina decipiens, de Koninck. Fig. 245. The exterior of a pedicle-valve with Ihe sliell partly exfoliated. Fig. 246. Posterior view ol' the brachial valve; showing elevation and lobation of the cardinal process. Fig. 247. The interior of a pedicle-valve; showing the median and lateral ridges. (Waagen.) 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. Type, Oldhamina decipiens, de Koninck. Carboniferous. India and China. Dr. Waagen has described the structure of these genera at great length, and i'rom 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 TnEcinF.mjE in palreozoic faunas. Kayser described, unler 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 RICHTHOFENIA, Kaysek. 1881. 1863. Anomia, de Koninck. Quarterly Journal Geol. Soc. London, vol. xix, p. 6, pi. iv, 6ijs. 7-9. 1863. Anomia, db Koninck. Foss. Paleoz. de I'Inde, p. 18, pi. iii, tig.s. 7-9. 1881. Rivhiliofenia, Kaysbr. Zeitschr. dei-deutsch. geolog-. Gesellsch., vol. xxxiii, p. 3.51. 1882. Aiwmia (RicMhofenla), Waaubn. Neues Jahrb. fur Mineral., vol. i, p. 115. 1883. RicMhofenia, Waagen. Records Geol. Survey of India, vol. xvi, pt. i, [). 12, pis. i, ii. 1883. RicMhofenia, K.atser. Richthofen's China, vol. iv, p. 195, pi. xxiv, figs. 6-8. IcSS.i. RicMhofenia, Waagen. Productus-limestone Fossils; Brachiopoda, pp. 733-743, pi. ixxxii, fig'. 1 ; pi. ixxxii A, fig;s. 1-4 ; pi. Ixxxiii, figs. 1-19. These peculiar fossils, which bear a striking external resemblance to certain operculated corals, and present some suggestive similarities to the lamellibranchs i'lo. 24S. Fro. 249. FlG. 250. Fio. 251. Richihofeiiia Lawrenciana, de Koninck. Fig. as. Tlic exterior of tlie two valves in .irticulation. Fig. 219. Longiludiual section of the pedicle- valve; showing the iuteiior cavity and the cellular shell substance. Fig. 250. The interior of the pedicle valve; showing the hingeliue and muscular scars. Fig. 251. The interior of the brachial valve. (Wa.^gen.) 316 PALEONTOLOGY OF NEW YORK. HiPPURiTES 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 hinge-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, Caprotina, 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 epithecal 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 ' CoralliopsidaJ " Two species of this genus have been described, the Anomia Lawrmciana, 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 i)i>. i:iS-!41.) Since the printing of the pages of this Volume, embracing the spire-bearing brachiopods, attention has been directed by Professor II. 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 I would describe as old-type genera for this Devonian period, i. e., preserving the form and general characteristics of the lower Silurian OrthidcR and StrophomenidcR, 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 NI A K Y. THE EVOLUTION OF THE GENERA OF TFIE TAL^-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- vag'es relating to the Inarticdlata, including- the concluding chapter referred to, had been completed and printed in ,Iuiy, 1890. Certain of these (pp. 120-lt;0), I'elating to the structure and devel- opment of the peiiicle-passage in Orbiculoidea, Schizookania, Tkematis, etc., were reset and issued sepa- rately at that date, with lithographic plates (IV e aud IV f), and this printed excerpt was distributed among students of the brachiopoda as well as to the general scientific public. t The subordinal classification of the Brachiopoda introduced by Waagen (1883-188.5) was based to some extent upon the conformation of the pedicle-passage. The phyletic value of variations in this structure was first clearly indicated by Eugene Deslokgchamps, 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 Lahradoricus, 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, undoubteilly, 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 Lingulops and Lingulasma toTRiMERELLA, by the progressive development of the vaulted muscular platform (see Part I, pp. 4G, 165, plates i, ii, \\a) 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 LakHxMINA, * Beeoher ; Dbvelniiuh-nl (if llie Bi-achiopoda, Part I, IiitroiUiotion ; Amei-ican .Joiii'nal of Science, vol. xli, p. 344. 1891. t In a later woi-k Mr. Walcott ha=i concluded that the Swanlon fossil is sufficiently distinct fi-om the typical Ohnlus (or Kutorglna) Lahradoricus to require a new designation, and has therefore termed it Kiitor- gina Lahradorica. var. Swa7ito)iensk (See "Fauna of the Lower Cambrian;" Tenth Ann. Rept, Director U. S. Geoloijical Survey, pi. Ixiv, figs 2, 3, dated 1S90, issued 1892). The fig-uros given in the work cited show that the var. Sivanfo7ien.iis is in n'.any respects the more primitive type, its valves being the more nearly equiconvex, its surface chai'acters simple concentric strijE, while in ihe typical 0. Labradoriciis, \heye \s a conspicuous elevation of the umbo of the pedicle-valve, a low median .sinus on the brachial valve, as well aa indications of radial plications about the beak ; all these are secondary characters which indicate progress tmvard (he ti'ue Kctorgin.*. (S" clngalata). It seemi evident that the generic term Paterix.\ was based upon the Swanton fo.ssil, and hence, if the author'.s intentions are cni-rectly interpreted, the type of the genus is Paterina SwantonensU, Walcott, As to the value to be ascribed to differences of shell-composi- tion within a given association of closely related genera, see remarks under the discussion of Lingcla and Trimerella, and in the following pages. 32li 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 Lingulacea 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 submarginal 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 been 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 been 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 makin'." 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 intei-relations as they ajipear 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 (Eiilert, 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 Eichwaluia 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 Waaoen 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 whoso fixation by means of a pedicle there is yet no evidence. The mode of development and enclosure of the marginal incision in the genus Orbiculoidea has already been demonstrated,! and it has been shown that ffiHLERTELLA, 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 (ffinLERTELLA), and wliilc these genera might be conveniently as.sociated 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 jirinted Daikadlia, probably a typographical error in the spelling' of the first syllables. Waagen, following usage in the employment of the terms Ltopomata and Arthhoposiata as ordinal designation.^, subordinate only to the name of the Class, Brachiopoda, iuti-oduced Mksocaulia and Diacai-lia as names of sjiborders. It is a purely arbitrary matter whethei- 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 Ihe fact that Waagex employed the lattei- 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. cit. 324 PALEONTOLOGY OF NEW YORK. In AcROTRETA, CoNOTRETA, LiNNARSsoNiA, AcROTHELE and IPHiDEA the i:)edicle- 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 Trematis-Orbiculoidea {DisciNin.E). The incipient formation of an inter- nal foraminal tube is seen in several of these genera (Acrotreta, Acrothele, Linnarssoxia), 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 Sipiionotreta 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, tlie 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 ajspear that this deviation took place during primordial times, as the typical Schizambon (S. typicalis, Walcott) is a primordial fossil. The newly described genus, Trematobolus, Matthew* (T. insignis, Mat- thew, type), 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 exter-nal groove has been a gradual one. They represent termini of slightly divergent series ; consequently they may all be safely *Canailian Record of Science, January, 1S93, pp. 277-279, figs. 1 o-d. BRACHIOPODA. 325 included under the old family designation introduced by Kutorga in 1848, SiPBONO TRETIDjE Crania and its allies (Craniell\, 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 Avas 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 Orbicoloidea ; 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-growtli 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 Crania and Pholidops to the Diac.\ulia. Present knowledge would seem to indicate that they were primarily of the type of the Mesocaulia, and that their resemblance to the Diacaclia is wholly of secondary growth.f * Quite early conditions of Crania siluHaiia and Craniella Hamiltoniw, from l.'t to .5 mm. in diameter, are fully cemented. E.iamjiles of Pholidops HainiltonioB, not above .5 mm in diameter, give no indication of a pedicle-jiassage or surface characters not present in the adult. t Some species of Pholidops {P. arenaria, P. Vivguloides) have a terminal subraarginal apex ; and their resemblance exterioi'ly to the oboloids is very striking. This is. however, no more than a re.serablance, as they show, on the under side, the same mode of peripheral growth beneath the beak as the other forms of the genus in which the umbones are more nearly central. 326 PALEONTOLOGY OF NEW YORK Waagen'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 diflerences 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 Spondylobolus, and among the siphonotretoids in Trematobolus. It is known that the shell of many inar- ticulates is almost Avholly calcareous, as in the Trimerellid^e 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 Avholly 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 adv^anced, 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 tlie ponderous Trimerellids of the later Silurian. The graduation of the corneous Paterina {Kutorgina Labradorica, var. Swanton- ensis) through Kutorgina Labradorica, and into the true calcareous Kutorginas {K. cingulata, K. Whitfieldi), 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 * Illustrations 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 comijosition 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 Kutorgina cingulata may retain a pedicle-covering or external sheath, in fact a true deltidiuin 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 Barroisella, 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 tlie suri\iccs 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- * Beecher, American Journal of Science, vol. xliv, p. 138. 1892. t Beecher, loc. cit. 328 PALEONTOLOGY OF ISEW YORK. mental, the latter is wholly secondary ; a replacement of, but never a derivative from the former. In the foregoing discussions of the genera these parts have been distinguished simply by the designations generally current ; the term deltidium referring exclusively to the convex external portion of the pedicle- sheath, such as occurs in Clitambonites, Strophomena, Rafinesquina, and their allies, and which, under no condition, shows evidence of composition or con- solidation of separate parts. The term deltidial plates has been applied to that condition of the external sheath in which a division into component parts is evident, as in Athyris, Atrypa, Merista, the terebratuloids, etc. ; or inferen- tial, as in CvRTiA and Cyrtina. The terminology is here so imperfect as easily to cause confusion, and though it had not seemed needful heretofore to suggest an improvement, it has become necessary, for the proper consideration of the subject, to employ a more distinctive expression for these fundamentally differ- ent structures. The secondary structures known as the deltidial plates, whether already discrete as in the terebratuloids, rhynchonelloids and meristoids, or solidly coalesced, as in Nucleospira, Parazyga, Cyrtia and Ctrtina, will hence- forward be termed the ddtarium, m application to the parts as a wliolo, or the deltaria in referring to the component plates. It may also prove convenient to adopt the terra introduced by Broxn, pseudodeltidium, for the coalesced condi- tion of the deltaria in Spirifer, Cyrtia, etc., as this is its original meaning ; but the significance of the term will be subordinate to that of deltarium. The researches by Kowalevski,* upon the development and detailed anatomy of Thecidea (Lacazella) and Cistella ( = Argiope, Kow.), have recently been interpreted in the bearing upon these structures by Beecher, who has also added new data derived from the study o? M igellania flavescens and Terebratulina septen- trionalis. Thecidea, or Lacazella Muditerranea, is the latest and only existing brachiopod which retains a true deltidium at maturity. Daring the cephalula- stage of the embryo, before the inversion of the mantle lobes to enclose the head, two shell-plates begin to form, one on the inner side of the dorsal mantle lobe, the other directly opposite to it on the outer surface of that portion of the * Obse7-vations on the Development of the Bi-achiopoda; Proceeding-s of the Session of the Imperial Society of Amateur Naturalists, etc., held at the University of Moscow, Eleventh year, vol. xiv. 1874. BRACHIOPODA. 329 body which subsequently becomes the pedicle. In this condition of growth the ventral lobe of the mantle is but slightly developed and bears no shell-plates. Fig. 252. FIG. 264. Flo. 257. Fig. 253. FIG. 255. Fig. 2.56. Fig. 258. Thccidia {Lacazella) Mediterranea. Fig. 2.52. Ceplialula, dorsal side; showiii;; below, Ihe ceplialic segment witli eye spots, and on the upper augment the dorsal shell -plate. Fig. 253. Dorso-veatrallongitudinal section of ceplialula; below is the cephalic se.ijment, at tlie right the dorsal mantle lobe, ihe darker line on its inner margin representing the beginning of the dorsal valve, and the similar line on the adjoining side of the body the incipient deltidium. Fig. 2.51. .V later growth-stage, in which the mantle lobes have turned downward. The body shell-plate is seen in the upper part of the figure. Fig. 255. Dorso-ventral longitudinal section of the preceding; showing the inversion of both mantle lobes. The relations of the dorsal and body (deltidium) plates are indicated by the heavy lines at the right. The ventral plate is also seen on the lobe at the left. Figs. 256. Prolile of a very young LeptfBtia rhomboidalis, oriented to correspond with the foregoing figures. Figs. 257, 2oS. Views of adult TIteciilea Mediterranea, similarly placed. (Beecher; 2gs. 252-255, .adapted from Kowalevski ) These features are seen in the accompanying figure of a longitudinal section of such an embryo. In the directly following growth-stage the reversion of the mantle lobes has taken place ; the shell-plate before on the inner surface of the dorsal lobe is now on its outer surface, and assumes the normal position of the dorsal or brachial valve. A corresponding plate has developed on the outer sur- face of the ventral mantle lobe, and between the inner edges of these two plates lies the great pedicle which bears on its dorsal side a third plate, meeting the dorsal, but widely separated from the ventral plate. This third pLite is the incipient deltidium. The deltidium is, thus, not a secretion from the mantle, but from the body of the embryo, and it has been shown that the shell-puncta- 330 PALEONTOLOGY OF NEW YORK. tions, which are usually present in the valves of the deltidiuni-l)earing species, such as Lepkena rhomboidalis, Chonetes scitula, etc., do not exist in the deltidiuni.* Fig. 259. riG. 261. Fig. 263. Fig. 260. Fig. 262. Cistella NeapoKtana. Fig. 264. Fig. 259. The complele'l oephalula-stage. Fig. 260. LoDgUudinal .section of same; the shell-secreling surfaces are represented by heavy lines. Fig. 261. The larva after inversion of the mantle lobes. Ftg. 262. Longitudinal section based on the preceding. The shell-bearing surfaces are now on the outside of the animal, the large pedicle extending upward. Figs. 263, 204. Dorsal and profile views of a very young shell; showing the large posterior opening between the valves and the thick pedicle. (Beeciiek -, adapted from Kowalevski and Shipley.) In the corresponding stages of growth in Cistell.v and TeREBR.iTULiNA, there is no evidence of this body-plate, no indication in any growth-stage of a delti- diuni, but the pedicle-passage formed by the ultimate union of the valves at their cardinal extremities remains uncovered until a comparatively late stage. By removing the shell from adult specimens of Terebiiatulina and Magellania in which the deltaria have become more or less completely developed, it has been *In Aolosteges the surface of the ileltidium is coveretl with short spinules or tubercles. Such spinules in the jiroductoids imply a punctation of the shell, wherever occurring- on the valves, but an examination of the deltiiliura in thi.s g-enus indicates that the secondary modification of the surface of the deltidium is not accompanied with a punctate structure. BRACmOPODA. 331 found that these plates are derived from two secondary expansions of the man- tle of the pedicle,valve enveloping the base of the pedicle.* These manifest themselves only in later or post-larval growth-stages, and as they are a product of the mantle lobes, may partake of the same punctate structure as the valves. Fig. 263.. Flcdicle. 270. Dorsal view of the unibonal portion of an adult TerebratuUna septcntriotuills, with the shell removed by acid; showing slight secondary extensions of tho ventral mantle at the base of the pedicle, small deltaria only being formed in this species. 271. A similar jireijaratiim ot Mnijellania fiatescens ; showing tho complete envelopment of the base of tho pedicle by secondary expansions of the ventral mantle, which have formed the deltaria, as shown in fig- 208. (Beeciieb.) These plates may unite along the median line, obliterate the foramen, or even extinguish all trace of their original division, as irequently 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 inti-oduction of the term that these processes in the two valves, though * Beecher, loc. cit. 332 PALEONTOLOGY OF NEW YORK. similar iu aspect, 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 spondtjlium 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 spoadijlium 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 lamellce, and forms a receptacle for the proxiiiial portion of the pedicle, and for the capsular or pedicle muscles. In Clitambonites and Pen- TAMERUS, 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 muscles, it will be evident that the plate is actually but a modification of the 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 iu 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 delli- 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 spondyliuin 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. Tlie deltidium unquestionably existed at an early stage and has usually become resorbed long before evidences of maturity in other re.spects aie assumed; the spondylium, also, does not pass beyond a condition which makes the pedicle-cavity a clearly defnied feature of the inte- rior. Tn more elementary or less modified orthoid structures like Billixgsell.a., PiiOTORTHis, and the Orthis dcfleda and 0. 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 l)otli features with a high degree of development, as in Cutamuonites, Polykeciiia, etc, indicates a more primitive condition than in Orthis, thougli 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 lamellte do not extend to the bottom of the valve, it seems necessarj^ 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 f\ict is afforded hy the genus Camaropiioria, which possesses a highly developed spon- 334 PALMONTOLOGY OF NEW YORK. dylium, while the deltidium has been resorbed and secondary deltidial plates or deltaria formed about the pedicle-passage. In the fundamental division of the Articulata two groups will be recognized, one embracing those forms in which the prodeltidium 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, Aphaneropegmata (1883), with the addition of Thecidea and its allies, and to Beecher's Protremata (1891), excepting the genus TnopiDOLEPTCS. 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 surfiice 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- amerus, 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, Renssel^eria, 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 tlie 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 lamelloB, 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. Tlie 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 EiciiwALDiA 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 AcLOcoRHYNCiins 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 pentameroids 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 group, it will probably be found to have this composition. Median and lateral septa, however, in the valves of ihe Brachiopoda, have a highly diverse origin in ilifferent cases. In most instances, except where bearing spondylia, they are evidently of muscular origin and surfaces of muscular attachment, as shown in Spirikerijia (see figure 42, page 53, and remarks in foot-note. Part I, p. 49) ; while in the Trlverellw^ they appear to be the residuum left by the resorption of a thick testaceous deposition about and beneath the area of muscular inseition. 336 PALEONTOLOGY 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 Conchiuium 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 mo.e 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 OitTHw.E, 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 ajipearance 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 Avould 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. BRACHfOPODA. 337 Under the guidance of tlie 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, Ortliorhynchula Linneyi is perhaps, by itself considered, the closest expression of the fundamental stock from which the rhynclionellids have Ijeen derived, but it is by no means the earliest of the group. It is known only in the latest fauna of tlie Lower Silurian, while in the earlier faunas, Protorhyncha, Rhynchotrema and Camarot(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, without modification, through preexist- ing forms as yet unknown. Such instances could be nmltiplied, 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 lamellte 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. defleda of the Trenton group, and O. ? laurentina of the Hudson River fauna, and it is continued without essential modification, except in the gradual contraction of the pedicle-cavity and deltidium, into Strophomexa of the Silu- rian, its allies and successors, Orthotiietes of the Devonian, and Derbya of tlie Carboniferous, Hipparionyx, Triplegia, Streptoriiynciius, etc., into Lept^ena, Rafinesquina, Stropheodonta, Plectambonites, CiioNETES 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 Leptostropiiia, where it has become almost, and sometimes quite oljliter- ated, and the entire pedicle and mnbonal 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 great 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 calladis, 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 Stropiiomena, 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 coatents of the pedicle-cavity may be represented by enorm- ous muscles whose scars extend almost to the anterior margin of tiie valve, as in HiPPARiONYX and Rhipidomella. In this great group of genera there are two types of contour, one, as in Lept^na, 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 corresjaondingly 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; A.mphistrophia is a reversed Brachvprion, both existing in faunas of the same age, and Stro- phomena is a reversed Rafinesquina, both similarly coexistent. With tliis presentation of the subject it seems neither necessary nor desirable to propose any bi-oad division of this group of genera. In 184G King proposed to embrace Stropiiomexa and its allies, in the family Stropbomenid^. The large number of generic values allied to Strophomena, which have been deter- mined since that date, make this comprehensive family divisible ad libilum, sed non in major em 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 ; lint in Lept^nisca and Davidsonia the attach- ment was maintained throughout tlie later existence of the shell. The impref ions left by the spiral arms upon the interior of the valves in Davidsonia and Lept^nisca, and also observed by Davidson in specimens of Rafinesquina Jukesi and Leptccna rhamboidulis, show a complete correspondence in the direction and curvature of the coils, and we are left to infer that other members of the BmopiroMENiDyE were in agreement with this structure, and, hence, that the arms in their uncalcified condition approached nearer the cal- cified spirals of Konikckikidj; (Coelospira, 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 w^e are acquainted with forms (e. g., Anoplia 7iucleata) in which these spine-tubes do not manifest them- 340 PALEONTOLOGY OF NEW YORK. gelves externally. Productus 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 AuLOSTEGES, 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 SmopnoMisKiDyE This group of genera has long been designated by the family name Piioductw.e introduced b}^ Gray in 1840, though, in correlating the various divisions of Waagen's proposed group, ApiiANERorEGMATA, there would be excellent reason for considering the chonetids and productids components of a subfamily infe- rior in value to the SrnopnoMENin.E and equivalent to the divisions Orthothetincz, Waagen, 1884, and Rafinesquininoi, Schuchert (emendatus), 1893.* Returning to the point of departure, we shall fiml that in the genus Orthis, which in its broadest significance is tantamount to the family Onrnin.E, Wood- ward, 1852, since the elimination of several heterogenous branches, the delti- dium was resorbed at an early stage of growth, leaving the delth3frium 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 0. callactis, 0. costaUs, 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 Strophomenid^ 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 "^ Ameiicau Geologist, vol. xi, p. 153. BRACHIOPODA. 341 already discussed. It appears ia a highly developed state in conjunction witli the unmodified deltidiuin, first in Protorthis, of the Cambrian, then in PoLYTCECHiA, Syntrophia, 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, 'SYaicoit, and Stricklandinia ? Balclekhensis, Davidson ; in the Silurian it is represented by Camarella and Parastropiiia ; also by the more rotund and more finely plicate shells, Anastrophia, Porambonites,Lycopiioria and NoETLiNGiA. 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 Lycopiioria and Noetlixgia 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, Barrandella, Sieberella, Pextamerella, Gypidula, Stricklandinia, Amphigenia); and, indeed, the last of these pentameroids, Cam- arophoria, of the Carboniferous and Permian faunas, is an exemplification of, and in fact a return to the rhynchonelloid exterior and the camarellid aspect, with 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 arched 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 coavex growths upon the marghis of the delthyriiira, which may- be interpreted either as remnants of a resorbed convex deltidium, or as highly accelerated secondary deltaria. Every now and then specimens will show a clearly developed cardinal area ; always in Stricklandinia, frequently and nor- mally in Gypidula, rarely and of exceptional occurrence in Pentamerella. Stricklandinia possesses so straight and long a hinge, so sharply defined an area and so short a spondylium, that it is more natural to regard this genus as the accompaniment, rather than the close organic kin of tlie other pentameroids, deriving its differentials directly from those long-hinged and straight-hinged shells of the early Silurian, which constitute the genus Syntrophia. It will not now appear a matter of inexplicable aberrancy that the spondylium presents itself in the great secondary groups comjirising the rhynchonellids, and those shells with calcified brachidia. Hence we meet with it in Cvrtina and Camarospira in a highly developed state, and in Camarotcechia in a less advanced condition, while Amphioenia presents the re:narkable combination of a spondylium coexistent with a shell of completely Rensselaerioid aspect (that is in respect to form, contour, muscular markings and articulating apparatus), an 1 with rhynchonelloid brachial supports. Attention has already been directed to the fact that some of the RnTNcnoNELLiDJi, carly in their history, occasionally retain a well-defined car- dinal area, and that, in default of other evidence, the presence of this char- acter may be regarded as indicative of the common origin of Orthis, the Stropbomenid^e, and the Rhynchonellas. The earliest phyletic stages of the rhynchonellids must have been highly accelerated, for there is no evidence of any form which has shown the slightest trace of a deltidium. Nevertheless the early forms of the Silurian, sach as Orthorhvnchula and Protorhyncha, rarely show any indication of deltaria at maturity but the delthyrium, in its final stage, is unobstructed and simple, as in young conditions of later rhynchonellids in which the deltaria fully develop. We may look upon the RarNcnoyELLiD.E as a family whose characters became established very early and have been per- petuated up to the present without departure, at any time, from the early derived type. BRACIIIOPODA. 343 In the study of the multifold variations of the articulates bearing calcified spiral brachial supports, the Helicopegmata of Waagen (1883), the conclusion has enforced itself that the degree of solidification of the brachia in this group is to be regarded as an index of differentiation. To illustrate : there is no evi- dence for assuming that the single volution made by the spiral in Protozyga and Hallina represents an incomplete spiculation of the brachia, or that the spiniform and discrete jugal processes in Spirifer, persisting throughout the genus, do not fully exemplify the adult condition of the jugum (^loop) in these shells. The mode of spiculation of the brachia in such of the living terebratuloids, in which the solidification is direct, or without complicated met- amorphoses, is on the whole confirmatory of this inference ; but as there is no living representative of the spire-bearing forms, evidence in regard to the mode and degree of spiculation in this group, derived from the existing loop- bearing shells in which the brachial supports pass througli highly complicated metamorphoses, is not altogether germane. In such intricate structures as the bracliidia of Athyris, Kayseria, Koninckina, etc., there can be little doubt that the calcified apparatus represents the full extent of the fleshy brachia simply, if for no other reason, because the further expansion of tlie brachial laminaj would not Ije possible for want of space. Moreover, in the spiculation of the spirals in all these old shells there have been no changes of form in later growth except those proceeding from the normal process of resorption and deposition necessary for increase in size and length. The reason why the spiculation should be complete in the spire-bearing forms, while in the Ancylobrachia or the terebratuloids, it does not extend beyond the loop or the lateral extensions of the brachia, but in the Rnr.vcnoNELLiD.4s. affects only the crura, and in the STRornoMENiB^n, does not occur, even in the most elementary condition, is for future investigations to ascertain. The form of the paired spirals varies but little except under the necessity of conformino- to the interior Cavitv of the valves. Their inclination and direc- tion is a feature of much significance when considered with reference to the development of the entire shell. It is the loop, or to employ a term more appropriate in view of the homologies of the spire-bearing and loop-l)earing 344 PALJEONTOLOGY OF NEW YORK. shells, the jugum, however, which is subject to the most frequent variations in form, and which serves as the generic index. When the spirals are directed outward toward the lateral margins of the valves, the jugum seems to be much more variable than in shells where the spirals are introverted or take some intermediate position. In the latter there is a much greater variation in the position of the loop upon the primary lamellaj than occurs in the former. The earliest spire-bearing shells yet discovered are the simplest in the structvn-e of the brachidium. Hallina, Protozyga, Cyclospira, of the Lower Silurian, possess brachidia which make a little less than one or two volutions of the calcified lamellaj, with a slight inclination toward each other, and to the median axis of the shell. Zvgospira and Glassia, the contemporaries and suc- cessors of these primitive structures, show progressed conditions of the same form of brachidium. In these genera, however, there is a slight deviation in the vertical axes of the spirals from the transverse axis of the shell, the apices being inclined somewhat toward the brachial valve, and this tendency to lateral evolution in the spiral cones is carried to its extreme in the genus Atrtpa, where the multispiral cones of the fully matured forms of the Devonian may sometimes have their axes nearly parallel. This is the termination of all revo- lution of the cones, a change through an arc of less than 90°, probably due in a large degree to alterations in the form of the internal cavity of the valves ; and the fact that this revolution here ceases, strictly delimits the group of forms bearing spirals to this type {Atuyfwjs). It is well to emphasize the fact, lest misconceptions already set on foot should become prevalent, that no wider revolution of the spiral cones exists. It is true that there is a difference of ISO*^ in the position of the axes of the spiral cones in Cvclospira and Spirifer, but the spirals have never, by gradual changes, revolved from their mverted position m the former to their everted position in the latter Such a process might have been possible, but had it actually occurred the forms resulting would have been totally different in structure from any now known. Instead of having the primary lamelliB and jugum on tha dorsal side as in all shells with everted spirals, these parts would lie on the ventral side of the shell. It must hence be inferred that the BRACHIOPODA. 345 SpiRjFEMiD^, the ATnrniD.E, the Meristid^, and all genera with everted brachidia are related to the A-rnrj'in.K only through their early ancestral forms. The Lower Silurian faunas have furnished no evidence of species with everted spirals, and this hiatus in our knowledge forbids any satisfactory deduc- tions as to the source or derivation of these forms. It is true in a general sense that the eversion of tlie spirals is accompanied by a convexity of both valves, just as the inverted spirals of the AmYriDjs are associated with valves of notably unequal depth. Still, among the latter, Glassia possesses biconvex valves, while of the former the group composed of Ccelospira, Anoplotheca, KoNiNCKiNA and Amphiclina, is characterized by convexo-plane or convexo- concave valves. In this group also the apices of the spirals are not directed toward the lateral commissures of the valves, but toward the lateral slopes of the pedicle-valve, such a form and direction being a necessary outcome of the contracted interior space. From present evidence it would seem probable that among the early Silurian species will be found some form whose spiral ribbon deviates outwardly from the vertical plane to the same degree as it inclines inwardly in Cyclospira and Protozyga. Indeed, in Cydospira bisulcata itself, the spiral sometimes lies so nearly in the vertical plane that the inward inclina- tion of the apices is not always positive. Only some such ibrm of the earliest faunas could have been the progenitor of the everted spirals. In the Atryi'id^, possibilities of a variation in the form of the jugum were much restricted ; in the other groups of the spire-bearers these were very great, and resulted in the production of a wonderful series of modifications whose relations it is not necessary to rehearse here. The extreme range of these modifications is seen in the simple termination of the jugum in Wiiitfieldella, Rhynchospira, etc. ; the bifurcate extremity in Meristina, Eumetria and Retzia, their terminal branches in Katseria, Diplospirella, etc., finally becoming co- extensive witli the lamelljB of the primary spirals and thus forming a second pair of spiral cones. This complication of the brachidium is effected only late in the history of the various groups producing them. Koninckina and Amphi- CLiNA are double-splraled convexo-concave shells, which are the post-palaeozoic and final representatives of Anoplotheca and Ccelospira. Pexidella and Diplo- 346 PALEONTOLOGY OF NLW YORK. SPIRELLA, of the St. Cassian beds, are double-spiraled athyroids ; Kayseria, of the middle Devonian, which is the only double-spiraled form known in the Palasozoic, appears to be an aberrant and accelerated representative of the stock which by more gradual development produced Retzia and Eumetria. Only one large group of spire-bearing shells retains the cardinal area, namely, the SpiniFEitwjs, a family with everted spirals, one of the earliest to appear and the la-t to disappear. Its abundant representatives possess the longest of spirals, and for the most part these are greatly extended transversely, held at arm's length as it were, unsupported by a connecting jugum (except in the sparsely represented genera Cyrtina and Spiiiiferina) ; but in spite of the deli- cacy of the structure and its apparent mechanical disadvantages in the absence of a continuous jugum, this type of structure has maintained its distinctive char- acter and multiplied in a most remarkable manner. The relations of the brachiopods with spiral brachidia to the Ancylobrachia, or those shells commonly spoken of as the terebratuloids, has been a fruitful sub- ject of discussion, and given rise to investigations of great astuteness and merit. Reference has already been made to the facts established by BEECHEa and Schuchert, from the development of the brachidium in Zygospira, which show that this atrypid passes through a growth-stage in which the brachidium has a simple terebratuloid form, similar to that in the mature condition of Dielas.ma; that the spirals are formed by the continued growth of the descending lamellae of the loop beyond the point of their recurvature into the ascending lamellas. What is thus true of Zygospira we must assume to have been equally true of all the spire-bearers, and the analogies thus establislied between them and the loop-bearing shells are these : The entire loop in Dielasma, Cryptonella, etc., corresponds to that portion of the brachidium, in the spire-bearing forms, which lies behinil the anterior basal edges of the jugum ; the descending lam- ellae of the former represent only the posterior portion of the primary lamellae of the latter, while the ascending lamellse and transverse connecting band of the Ancylobrachia are the equivalent of the jugum in the spire-bearers. The spirals, however, are a later development in the individual, and are hence undoubtedly a subsequent phyletic condition. Hence it is inferred that the BRACHIOPODA. 347 spire-bearing forms derive! their brachidia from a primitive terebratuloid con- dition, and this derivation has been effected by growth with accompanying resorption. The progressive modification of the loop in the recent terebratellids by resorption of calcareous tissue in the growth of the individual, is a well- known fact which has invited the study of many investigators. In such forms this modification is extreme, and is unquestionably complicated by the intimate connection of the loop with the median septum of the brachial valve. With the single exception of Tropidoleptus, among the palaeozoic genera, there is no clear evidence that the median septum has shared in, or contributed to, the growth-modification of the brachial supports ; nevertheless, the outcome and final result of this growth with modification in the most progressed forms of Terebratella and such palasozoic genera as Dielasma, Cryptonella, Harttina, etc., is the same. Progressive modification of the brachial supports in both the Helicopegmata and palasozoic Ancylobrachia being now fully established, it is interesting to observe that the primitive condition of the loop, as in Dielasma turgida, is one of simjjle apposition of the two short brachial processes, at their expanded anterior extremities ; having the expression of the mature loop in the genera Centronella, Rensselaeria, Selenella, etc. A simple step further back would afford a condition in which the brachial processes with their expanded extrem- ities are not as vet united, but discrete as in the rhvnchonellids. A more primitive condition than that in Centrone.lla or the centronellfd stage in Dielasma, could not be different from this. On the ground of these differences in the conditions of the brachidium and the phyletic stages corresponding thereto, it would seem fair to infer that, of the rhynchonellids, the terebratu- loids and the spire-bearers, the first is the primitive stock, and the spire- bearers legitimate derivations from that stock, through the terebratuloids, or both of the latter derived along divergent lines from the rhynchonellids. This conclusion, however coherent and consistent with the geological evidence, will be found to lack stability until the data are sufficient to establish the fact that the brachia themselves, and not alone their calcareous supports, have passed through corresponding phases of growth and derivation. This latter question 348 PALEONTOLOGY OF NEW YORK. must long be a matter of legitimate speculation, and in view of this fact a few arguments of such a nature in this place will be permissible. The living representatives of Rhynchonella and Terebratula are animals in which a very considerable part of the brachia does not become sufficiently spiculized to form a continuous calcareous support. In R. {Hemithyris) psittacea, for example, the brachia are as highly developed in the form of coiled spiral arms as they could have been in most of the ancient spire-bearers, but their calcareous supports are only the short lamellse known as the crural processes. All of the living Ancylobrachia which possess a long curved loop lilce that of Cryptonella and DiELASMA of the Palaeozoic, have an unsupported median unpaired spiral arm, coiled in a direction which is the reverse of that prevailing among the spire- bearers If, now, we are to interpret the condition of the brachia in their nearest living representative, it becomes necessary to assume that on the one hand, the palaeozoic rhynchonellids possessed long coiled spiral arms, and, on the other, that Dielasma and its pala30zoic allies and affines, when mature, were provided with the unpaired coiled arm of Terebratella. This assumption, in the first place, totally destroys the inference above made as to the primitive relation of the rhynchonellids to the terebratuloids and spire- bearers j and, secondly, would seem to necessitate a novel and unexpected interpretation of the brachial structure in all the spire-bearers. If Dielasma possessed the median arm, supported at its base by the transverse band of the loop, which corre- sponds to the jugum of the spire-bearers, then in the DiELASMA-stage of Zygo- SPiRA and other spiriferous shells, where this stage was well defined, there must also have been a median coiled arm of some extent. This median arjn, in living forms, is due, as shown by Beecher, to the necessity of finding room for the cilia or tentacles multiplying at the extremities of the brachia. The mere presence of the transverse band in Dielasma and the DiELASMA-stage of Zygo- spira, implies a similar extension of the brachia, and from the analogy, a median arm. The subsequent growth of the brachia in Zygospira, carrying the calca- reous ribbon forward, beyond the bases of the loop and into lateral spiral cones, would not of itself afford sufficient reason for assuming that the growth of the brachia at their extremities, which produced the median arm., was necessarily BRACHIOPODA. 34') discontinued, but rather that this median unpaired arm coexisted with the lateral paired spirals. This course of argument, though seemingly logical appears, to be based on insufficient premises. The brachiopods with which we have to deal in tlie pal33ozoic are essentially primitive structures, whetlicr rhynchouellids, terebratuloids or spire-bearers. If the living Rhynchonella and Terebratella in their mature conditions possess extensive unsolidified arms, it does not necessarily follow that their early palaeozoic representatives were provided with similar uncalcified extensions; on the contrary, it would be much more reasonable and in accordance with our knowledge of natural laws to infer that in these early forms the adult condition of the brachia was more nearly that of immature conditions of these organs in their living representatives. There is a primitive condition of development in the terebratuloids in which the loop is coextensive with the brachia ; there is reason to believe that such has been the relation of these parts in the mature phases of the primitive terebratuloids, as Centronella, Rensselaeria, Crypto- NELLA, DiELASMA, ctc. ; in Tropidoleptus, which has been shown to represent a highly jDrimitive phyletic condition of the TEiucnnATELLiD.E; and, also, in the earliet spire-bearers and rhynchouellids. Hence the conclusion above expressed as to the successive phyletic relations of the primitive rhynchonellids, terebra- tuloids and spire-bearers, and based upon the relations and modifications in the form of their brachial supports, is fairly substantiated by the evidence drawn from other data. 350 PALAEONTOLOGY OF NEW YORK. Finality , it is important to emphasize the intimate similarity between Rensse- LAERiA and the pentameroid genus Amphigenia ; genera in which the essential distinction between the typical forms of each lies in the simple loop of the former and the long, expanded but still discrete crural processes of the latter. Attention has been directed to these similarities and differences, and it has also been pointed out that the spondylium in Amphigenia elongaia is at times almost reproduced in specimens of Rensselaeria ovoides where the dental lamellae are highly developed. TABLE OF CLASSIFICATION. CLASS BRACHIOPODA. Paterina,* Beecher, 1891. Sub-class INARTICULATA, Huxley; LYOPOMATA, Owen. Order Mesocaulia, or Lingulacea, Waagen. Family OBOLID^, King. Obolus, von Eichwald, 1829. Obolella, Billings, 1861. Ungula, Pander, 1830. Discellomus, Hall, 1871. Ungulites, Bronn, 1848. Elkania, Ford, 1886. Aulonotreta, Kutorga, 1848. Billingsia, Ford, 1886. Acritis, Volborth, 1869. Botsfordia, Matthew, 1893. ScHiMiDTiA, Volborth, 1869. Neobolus, Waagen, 1885. Mickwitzia, Schmidt, 1888. Monobolina, Salter, 1865. Spondylobolus, McCoy, 1852. Family LINGVLIDJE, Gray. LiNGULA, Bruguiere, 1792. Leptobolus, Hall, 1871. Pharetra, Bolten, 1798. Glossina, Phillips, 1848. Lingularius, Dumeril, 1806. Dignomia, Hall, 1871. * The genus Paterina, i-epreseuting-, according' to our present knowleilge, the fundamental stock or radicle of all the Brachiopods, might be embraced by some of the primiti\-e families, both of the Inarticii- lata and the Articulata. By placing it in this arrangement, outside both the gi-eat sub-classes, it is the purpose to express the fact that the genus belongs as much to one as to the other, and that it is actually beyond the pale of both as it has not assumed the differential characters of either. 352 PALEONTOLOGY OF NEW YORK. LING ULID^^;— Continued. LiNGULELLA, Salter, 1866. Barroisella, Hall, 1892. LiNGULEPis, Hall, 1863. Tomasina, Hall, 1892. Family TRIMERELLIDJE, DAvrnsoN and King. Lakhmina, CEhlert, 1887. Conradia, Hall, 1862. Davidsonella, Waagen, 1885. Obolellina, Billings, 1871. LiNGULOPS, Hall, 1871. Monomerella, Billings, 1871. LiNGULASMA, Ulricli, 1889. Trimerella, Billings, 1862. DiNOBOLus, Hall, 1871. RhiNobolus, Hall, 1874. Order Diacaulta, or Discinacea, Waagen. Family DISCINIDJE, Ghay. DisciNOLEPis, Waagen, 1885. Lingulodiscina, Wliitfield, 1890. Paterula, Barrande, 1879. Orbiculoidea, d'Orbigny, 1847 ScHizoBOLUs, Ulrich, 1886. Schizotreta, Kutorga, 1848. Trematis, Sharpe, 1847. Lindstrcemella, Hall, 1892. ScHizocRANiA, Hall and Whitfield, 1875. Roemerella, Hall, 1892. CEhlertella, Hall, 1892. Family SIPHONOTRETIDM Kutorga. Acrothele, Linnarsson, 1876. Schizambon, Walcott, 1884. Linnarssonia, Walcott, 1885. Siphonotreta, de Verneuil, 1845. DisciNOPSis, Matthew, 1892. Orbicella, d'Orbigny, 1849. Acrotreta, Kutorga, 1848. Kei/serlingia, Pander, 1861. Conotreta, Walcott, 1889. Helmersenia, Pander, 1861. Mesotreta, Kutorga, 1848. Order Gastropegmata, or Craniacea, Waagen. Family CRANIIDM, King. Crania, Retzius, 1781. Cnqpas, Poli, 1791. Numulus, Stoboeus, 1732. Criopoderma, Poll, 1791. Ostracites, Beuth, 1776. Orbicula, Cuvier, 1798. BRACHIOPODA. 353 CRANIID^S^Continutd. Orbicularius, Dumeril, 1806. Pholidops, Hall, 1869. Craniolites, Schlotheim, 1820. Choniopora, Schauroth, 1854. Craniella, CEhlert, 1887. Cardinockania, Waagen, 1885. Craniops, Hall, 1850. Pseudocrania, McCoy, 1851. Palmocrania, Quenstedt, 1871. Sub-class ARTICULATA, Huxley; ARTHROPOMATA, Owen. Order Protremata,* Beecher. Family KUTORaiNIDMA Schdchebt. KuTORGiNA, Billings, 1861. (?) Volborthia, von MoUer, 1873. ScHizoPHOLis, Waagen, 1885. Iphidea, Billings, 1872. Family ORTHIBM, Woodward. Orthis, Dalman, 1828. Orthambonites, Pander, 1830. Plectorthis, Hall, 1892. Dinorthis, Hall, 1892. Plaesiomys, Hall, 1892. Hebertella, Hall, 1892. Orthostrophia, Hall, 1883. Platystrophia, King, 1850. Heterorthis, Hall, 1892. BiLOBiTES, Linne, 1775. Dicoelosia, King, 1850. Dalmanella, Hall, 1892. Rhipidomella, ffihlert, 1880. Rhipidomijs, CEhlert, 1887. ScHizopHORiA, King, 1850. Orthotichia, Hall, 1892. Enteletes, Fischer de Waldheim, 1830. Syntrielasma, Meek, 1865. Family STROPHOMENID^., Kikg. Orthidium, Hall, 1892. Derbya, Waagen, 1884. Strophomena, Rafinesque (de Blain- Meekella, White and St. John, 1868. ville), 1825. Streptorhynchus, King, 1850. * In employing' as the fundamental divisional di.«tiuction in the Articulata, the presence of the deltidiuni or deltidial ]ilates, the term Protremata, lietter than any other, covers those genera in which the primitive pedicle-covering- is I'epresented by either the deltidium, the spondylium, or both. + Jlr. ScHucnERT includes under this family term two genera, Ki'torgina and Schkopbolis, which have usually been regarded as belonging to the inarticulate sub-class. The rea-sons foi- installation of these as the elementary family of the Articulata are given elsewhere. 354 PALEONTOLOGY OF NEW YORK. f'^TROPHOMENIDJR— Continued. Orthothetes, Fischer de Waldheira, Triplegia, Hall, 1858. 1830. Dicraniscus, Meek, 1872. HiPPARioNYX, Vanuxem, 1842. Mimulus, Barrande, 1879. Kayserella, Hall, 1892. Streptis, Davidson, 1881. Family LEPTJENIDzR. Lept^na, 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. Ciiristiania, Hall, 1892. DouviLLiNA, QEhlert, 1887. LEPTiENiscA, Beecher, 1890. Leptostrophia, Hall, 1892. Davidsonia, Bouchard, 1847. Pholidostrophia, Hall, 1892. Family CHONETIDJE. Chonetes, Fischer de Waldheim, 1837. Chonetina, Krotow, 188.S Anoplia, Hall, 1892. Chonostrophia, Hall, 1892. Chonetella, Waagen, 1884. Chonopectus, Hall, 1892. Family PRODUCTTDJR, finAv. Strophalosia, King, 1844. Productella, Hall, 1867. Orthothrix, Geinitz, 1847. Productus, Hall, 1867. Leptanalosia, King, 1845. Marginifera, Waagen, 1884. Daviesiella, Waagen, 1884. Proboscidella, CElilert, 1887. AuLOSTEGEs, von Helmersen, 1847. Etheridgina, CEhlert, 1887. Family THECIDIIBM, Gray. Lyttonia, Waagen, 1883. Oldhamina, Waagen, 1883. Family RICHTHOFENIDM Waagen. RiCHTHOFENiA, Waagen, 1883. BRACHIOPODA. 355 Family BILLINGSBLLID^. Schucheht. BiLLINGSELLA,* Hall, 1892. Family CLITAMBONITID.Ti, N. II. Wi.vchell and Sciicciibrt. Protorthis, Hall, 1892. Hemipronites, Pander, 1830. PoLYTCECHiA, Hall, 1892. Orthisina, d'Orbigny, 1847. Clitambonites, Pander, 1830. Scenidium, Hall, 1860. Prnnites, Pandei-, 1830. Mystrophora, Kayser, 1871. Gonambonites, Pander, 1830. Family ^^TRICKLANDINIID^. Stntrophia, 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, Laliusen, 1885. (?) Branconia, Gagel, 1890. Camarophoria, King, 1846. Camarophorella, Hall, 1893. Family PENTAMERID^f:. CoNCHiDiuM, Linne, 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 geniis Billingsella, in correspondence with its early geological age, present.s an elementary structural aspect indicating that it may have served as a point of departui-e for the Obthidm and Stbophomesid^. 356 PALAEONTOLOGY OF NEW YORK. Order Telotremata, Beecher. Sub-order Rostracea, Schuchert. Family RHYNCHONELLID^, Gray. Protorhyncha, Hall, 1893. Uncinulina, Bayle, 1878. Orthorhynchula, Hall, 1893. Hypothyris, (McCoy) King, 1850. Rhynchotrema, Hall, 1860. Pugnax, Hall, 1893. Rhynchotreta, Hall, 1879. Eatonia, Hall, 1857. Stenoschisma, Conrad, 1839 Cyclorhina, Hall, 1893. Camarotcechia, Hall, 1893. Terebratuloidea, Waagen, 1883. LioRHYNCHUs, Hall, 1860. Rhynchopora, King, 1856. WiLSONiA, (Quenstedt) Kayser, 1871. Rhynchonella, Fischer de Waldheim, Uncinulus, Bayle, 1878. 1809. Sub-order Ancylobrachia, Gray. Family CENTRONELLIDM, Waagbn. Rensselaeria, Hall, 1859. Romingerina, Hall, 1893. Beachia, Hall, 1893. Trigeria, Bayle, 1875. Newberria, Hall, 1891. (?) Notothyris, Waagen, 1882. Ce.ntronella, Billings, 1859. Scaphiocceli a, Whitfield, 1891. Oriskania, Hall, 1893. Megalanteris, Suess, 1855. Selenella, Hall, 1893. (?) Enantiosphen, Whidborne, 1893. Family l^TRTNGOCEPHALID^, Dall. Stringocephalus, Defrance, 1827. Family TEREBRATULID^. Dall. Cryptonella, Hall, 1861. Cran^ena, Hall, 1893. Eunella, Hall, 1893. Dielas.mina, Waagen, 1882. Harttina, Hall, 1893. Hemiptychina, Waagen, 1882. DiELASMA, King, 1859. Beecheria, Hall, 1893. Epithyris, King. 1850. (?) Cryptacanthia, White and St. John, 1867. BRACHIOPODA. 357 Family TEREBRATELLIDJE, Kino. Tropidoleptds, Hall, 1857. Sub-order Helicopegmata, or Spiriferacea, Waagen. Family ATMTPID^, Dall. Hallina, N.H.WinchellandSchuchert, Cataztga, Hall, 1893. 1892. Glassia, Davidson, 1882. Protozyga, Hall, 1893. Atrypina, Hall, 1893. (?) Cyclospira, Hall, 1893. (?) Clintonella, Hall, 1893. Zygospira, Hall, 1862. Atrypa, Dalman, 1828. Anazi/ga, Davidson, 1882. Karpinskia, Tschernyschew, 1885. Orthonom^a, Hall, 1858. Gruenewaldtia, Tschernyschew, 1885 Family SPIRIFERINIDJE, Davidson. Cyrtina, Davidson, 1858. Spiriferina, d'Orbigny, 1847. Family SPIRIFERIDJE, King. Spirifer, Sowerby, 1815. Martinia, 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. Amboccelia, Hall, 1860. Delthyris, Dalman, 1828. Metaplasia, Hall, 1893. Reticulakia, McCoy, 1844. Verneuilia, Hall. 1893. Family NUCLEOSPIRID^^, Davidson. NucLEOSPiRA, Hall, 1858. Whitfieldella, Hall, 1893. Dayia, Davidson, 1882. Hyattella, Hall, 1893. HiNDELLA, Davidson, 1882. (?) Camarospira, Hall, 1893. Family CCELOBPIRIDM. Anoplotheca, Sandberger, 1856. Leptoc(ELIA, Hall, 1859. Bifida, Davidson, 1882. (?) Anabaia, Clarke, 1893. C(EL0SPiRA, Hall, 1863. 358 PALEONTOLOGY OF NEW YORK. FAMaT RETZIID^. Rhynchospira, Hall, 1859. Retzia, King, 1850. HoM(EOSPiRA, Hall, 1893. Uncinella, Waagen, 1883. Ptychospira, Hall, 1893. Eumetria, Hall, 1864. Trematospira, Hall, 1857. Acambona, White, 1862. Pabazyga, Hall, 1893. Hustedia, Hall, 1893. Family VNCITIDm, Waaobn. Uncites, Defrance, 1825. Family MERISTELLIBM, Waagen. Merista, Suess, 1851. Charionella, Billings, 1861. Camarium, Hall, 1859. (?) Pentagonia, Cozzens, 1846. DicAMARA, Hall, 1893. Gmiocalia, Hall, 1861. Meristella, Hall, 1860. Family ATHTRID^. Waagen. Meristina, Hall, 1867. Cliothyris, King, 1850. Whitfieldia, Davidson, 1882. Actinoconchus, McCoy, 1844 Glassina, Hall, 1893. Seminula, McCoy, 1844. Athyris, McCoy, 1844. Spirigerella, Waagen, 1883. Sptrigera, d'Orbigny, 1847. Kayseria, Davidson, 1882. INCERTJE SEDTS. EicHWALDiA, Billings, 1858. Aulacorhynchus, Dittmar, 1871. Didyonella, Hall, 1867. Jsogramma, Meek and Worthen,1873. DESCRIPTIONS OF NEW SPECIES FIGURED IN VOLUME VIII, PART II. OrTHIS ? QLYPTA, Sp. nOV. PLATE LXXXIV, 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 surfiice similar to that occurring in the Swedish Silurian species, 0. J^ovem, Lindstrom The muscular area of the pedicle valve is small. Length of an average pedicle-valve, 12 mm. ; width, 18 mm. Niagara dolomites. Near Milwaukee, IVtsconsm. Strophonella costatula, sp nov. PLATE LSXXIV, FIGS. 1.'). 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. Correspondmg 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 pboducta, sp. nov. PLATE LXXXIV, FIGS. 23, 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 mm.; from the anterior margin, 28 mm. Niagara dolomites. Yellow Springs, Ohio. Spibifer crispatus, 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, 24, 25. Shells of rather small size, having somewhat the aspect of an elongate and umbonate S. 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. Spirifer mucronatcs, Conrad, var. posterus, var. nov. PLATE XXilV, FIGS. 27-31 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. Spirifer disjunctds, Sowerby, var. sdlcifer, 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 S. disjundus, Ijut 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. Spirifer Newberryi, Hall. 1883. (See Report State Geologist for 1882, Plate (xxxi) 56, Figs. 9, 10). PLATE XXXI, FIGS. 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 2)lications and the grooves between them are covered with fine radiating lines. Waverly group. Ohio. Cyrtia radians, sp. nov. PLATES XXVIII, FIGS. 4, 5, 50, 52 ; XXXIX, FIG. 33. 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 strioe. 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 XXVIII, FIGS. 16-20. 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 XXVIII, FIGS. 36, 37, 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. BRACHTOPODA. 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. Syrinqothtris 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 laminJB. Height of original specimen, 13 mm. ; cardinal width, 18 mm. ; length, 15 mm. Choteau limestone. Chateau Springs, Missouri. Amboccelia spinosa, sp. nov. PLATE XXXIX, FIGS. 16-lS. 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. Seminula Rogersi, sp. nov. PLATE XL VII, FIGS. 1-4. Shell rather dinall, sul)()val 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. Athyris densa, sp. nov. PLATE XLVI, FIGS. G-12. 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 XLVII, FIGS. 32-34. (See ii!ige.s 95, 96.) This species was originally identified as Athyris subtilita, Hall, by Davidson (Quarterly Journal of the Geological Society of London, vol. xix, 1863). Its differences 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 ; XHV, 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, pp. nov. PLATE XLII, FIGS. 1-fl. 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. Porrij countij, Tennessee. Zygospira putilla, sp. nov. PLATE LIV, FIGS. 35-:)7. 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 Ijrachial 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 LXII. FIGS. 25-29. 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, witli 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 LXIII, 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 conspicuous ; from the gently convex umbo the surface slopes BRACIIIOPODA. 3G7 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 unilxmal region, but the median fold is defined only near the anterior nuu'gin. It bears from three to five pli- cations, with three on each 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 strongly .defined 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 LXm, FIGS. 1.5, 16, 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 PALAEONTOLOGY OF NEW YORK. Pabastrophia latiplicata, sp. nov. PLATE l.XIII FIGS. 23-27. 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. LiORHYNCHUS Lesleyi, sp. nov. PLATE LIX, FIGS. 34-36. Shell of medium size with shallow pedicle-, and deep brachial valve. Median sinus on tlie 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 pallial region, from forty-five to fifty rounded plications, BRACHIOPODA. 369 which very gradually increase by iniplantation 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 Mihvaukee, Wisconsin. CONCHIDIUM CRASSIPLICA, sp. UOV. PLATE LXVI, FIGS. 24, 25. 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 l)rachial valve depressed, apex concealed ; median region depressed anteriorly ; surface of both valves bearing broad rounded plications, separated by deep grooves. Of these plications thei-e 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 Georgia, sp. nov. PLATE LXVI, riGS. IS, 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 jura, sp. nov. PLATE LXX, FIGS. G-U. (See pages 248, 249.) 370 PALEONTOLOGY OF NEW YORK. Selenella gracilis, sp. nov. (See page 270, figs. 184-186.) Oriskania navicella, sp. nov. PLATE LXXIX, FIGS. 26-27. (See pages 269, 270, figs. 181-183.) RensselvEria Cayuga, sp. nov. PLATE LXXV. FIGS. 1, 2. Shell lenticular, often of large size ; suboval in marginal outline. Valves subequally biponvex, 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. Beecheria 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. (These references do not include names used in association with specific designations.) Abich, H., Agassiz, A., Agassiz, L., Aldrovandus, Allen, W. F., Ami, 11 M., Augelin, N. P., . Arcliiac, E. J. A. D. de St. S. d', I, 261, 263; U, 265 . 11, m . I, 2o3; II, 193 I, 186 II, 260 . I, 79, 113, 115 I, 201; II, 230, 234 I, 253, 303,317; U 1 57,101,112, 131, 172,178, 282 Ast, Ph , .... I, 213 At water, H, 1, 14 Barrande, J , . I, 36, 68, 73, 78, 79, 98, 101, 105, 127, 133 131, 112, 200, 272, 273, 274, 285, 290; II, 12, 14, 62, 70 77, 107, IRS, 231, 235, 241 , 242, 244,245, 2S6, 288,307.309, 310 Barrett, S. J I, 120, 142, 144, 285 Barris, W. H II, 196 Barrois, C , . . . . I, 285; U, 311, 312 Bayan, F., I, 264, 266 Bayle, . . . .II, 196, 197, 198, 199, 265, 273 Beach, A. C H, 260 Beecher, 0. E., . I, 146, 189, 206, 209, 254, 272, 273, 277, 290 291,300,301; II, 5, 13, IS, 59, lid. 69, 103,109, 101 164, 185, 219, 225, 265, 209, 294, 297, 305, 307, 309, 319 321, 322. 323, 327, 328, 329, 330, 331, 334, 336, 346 Bergman, . . . . . 1, 218 Beuth, F., I, 145; II, 113 Bdlings, E., . I, 3, 27, 33, 36, 40, 41, 44, 45, 56, 66, 67, 70 72, 75, 76, 7S, 90, 91, 97, 98, 101, 103, 120, 138, 142, 145 187, 183, 192, 194, 195, 190, 198, 201, 205, 208, 211, 217 221, 230, 232, 233, 242, 244, 245, 253, 269, 276, 281, 284 285, 286, 238, 290, 294, 295, 298, 303, 304, 311 ; H, 2 3, 12, 13, 15, 13, 22, 28, 40, 42, 43, 58, 62, 63, 04, 68, 73 78, 79, 80, 83, 88, 108, 109. 124, 127, 134, 149, 154, 157 158, 1.59, 163, 164, 189, 193, 212, 213, 214, 219, 220, 221 231, 233, 236, 241, 249, 250, 251, 252, 234. 255, 265, 273 286. 307, 310, 321 Billings, W. R, . . ... 11, 148 Binney, W. G. .1, 216 Bittner, A., , I, 298; II, 45, S7, 100, 102, 105, 122, 269, 272 Blainville, 11. M. U. de, . I, 245, 216, 247, 249, 250, 252 279; n, 178 Bolten . I, 2 Bouchard, . . . . . I, 301 Bronn, II. G , . . . I, 2, SO, ISO; II, 328 Brooks, Vf. K., I, 162 Bruguifire, J. G., I, 2, 321 Buch, L. von, . . 1,80,189,200.201,201,211,221, 233 . 253, 267, 276, 290, 303, 321, 333; II, 11, 12, 40, 112, 113 187, 195, 203, 203, 214, 225, 241, 282, 293 Calvin, S., Carpenter, W. B., Castelnau, F. de. PAGE. I, 188, 206, 285; IT, 4, 5, IS, 28, 32, fl5 241,294, 2!I7 . I, 149; 11, 49 . 1,187,200,250,276,281, 303 II, 1, 12, 14, 18, 28, 73, 163, 253 Chemnitz, J. H., I, 321 Clarke, J. M, 1,3,121,146,189,206,209,251,272, 273 277, 290, 291, 304; II, 4, 5, 13, 18, 28, 59, 66, 69, 109 141, 161, 104, 185, 193, 196, 203, 219, 225, 265, 269, 307, 309 Claypole, E. W , . . . U, M, 261 Clinton, G. n, 100 Conrad, T. A., . I, 2, 56, 69, 186, 137, 192, 196, 19j, 200 201 , 204, 205, 253, 257, 276, 280, 281, 281, 290, 295, 303 321,328; II, 1,12,14,18,21,28,31,51,73,80,83, 134 136, 163, 1S2, 183, 187, 189, 204, 231, 241, 255, 302 Cotton, U., I, 252 Co.x, E. T., . . . I, 3, 187, 211, 264 Cozzcns, 1., . . . . II, 80 Crane, A., II, 297 Cuvier, G. C. F. D 1, 1-22, 145, 150 Da Costa, E. M., I, 321 Dall, W. II., I, 2, 14, 33, 34, 36, U. 45, 83, 118, 120, 121 122, 123, 123, 138, 145, 150, 151, 1.55, 160, 236, 277 U, 138, 193, 255, 305 Dalman, J. W., . I, 186, 191, 192, 204, 205, 233, 236, 276, 277 2S0, 290, 295, 296, 297, 303, .■J21; II, 9, 40, 41, 58, 61 65, 67. 163, 185, 195, 231, 241 Dana, J. D ■ . I, 2 Darwin, C II, 137 Davidson, T., . . I, 8, 9, 10, 14, 15, 10, 17, 18, 19. 20 21, 22, 27, 31, 33, 34, 35, 36, 39, 40, 41, 43, 44, 45, 46, 48 51, .13, 5G,'o7, 68, 62, 63, 65, 66, 78, 79, 80, 83, 84, 85, 87 90, 91, 91, 93, 100, 101, 103, 107, 108, 110, 111, 112, 113 115, 120, 122, 1-25, 126, 127, 128, 129, 133, 13j. 141, 142 147, 14S, 149, 150, 151, 153, 1.55, 136, 138, 160, 191. 192 19.1, 200, 201, 202, 203, 201, 205, 211, 212, 214, 227, 233 241, 212, 213, 245, 216. 249, 250, 253, 254, 257, 259, 26l' 261, 267, 2GS, 269, 270, 271, 271, 279, 2S0, 281, 284, 23^ ■286, 290, 295, 296, 297, 298, 300, 301, 303, 301, 306, 313 314, 317, 319, 320, 321, 333, 331, 333; II, 2,7,8,9, 10 17, 20, 21, 22, 30, 33, 40, 41, 43, 50, 51, 53, 58, 60, 62 63, 65, 66, 67, 63, 70, 71, 73, 70, S3, 87, 88, 91, 92, 93 95,97,98, 101,103,112, 113. 114, 115, 122, 129, 131, 1.14 144, 149, 152, 153, 156, 1,58, 139, ICl, 103, 104, 168, 172 174, 178, 185, 187, 195, 196, 193, 200, 203, 204, 208, 210 21 , 215, 210, 217, 219, 221, 225, 227, 231, 236, 237, 240 241, 242, 243, 249, 250, •r>5, 205, 272, 274, 277, 281, 282 286, 288, 289, 293, 294, 295, 299, 300, 302, 305, 307, 3U 322, 339 372 INDEX. PAGE. Dawson, J. W., . I, 70, 107, liO, 285, 304. 322; U, 4, 15, 51 84,249,291, 293 Dechen, II. von, . . . . . II, 24 Defi-ance, . I, 215, 246, 247, 249, 250, 252; II, 113, 2S2 Derby, O. A., . I, 120, 145, 188, 208, 211, 213, 214, 216, 254 261,267,268,304,314,322; II, 3, 4,22, 51, 84, OS, 120 121, 122, 138, 140, 265, 266, 267, 272, 274, 286, 292, 293 302 Deslongchamps, E., ..... H, 320 Dewer.C ".1=8 Dittmkr, U.311, 312 Dumeril, A., I. 2, 145 Dwight, W. B.. 1. 118, 120, 136 Dyer, C. B., I. 138, 272 Eaton, A., H. S3. 255 Eiohwald, E. von, .1,80,110,1,52,200,201,221,233, 215 200, 269, 276, 297, 298, 321, 337; II, 225, 227, 230, 241 Emerson,B. K., . . . . I, 3, 30-1; II, 231, 273 Emmons, E., . 1,2,3,66,138,145,186,195,200,201, 205 215, 257, 269, 281, 295; II, 2, 12, 140, 231 Endlicher, I, 101 Etheri.lge, R., jr., I, 335, 336; II, 4, 51, (S, 164, 231, 242 Evans I, 25G Fahrenkohl, A., I, 303 Fischer Ue WaUlhcini, . 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, 250 Ford, S. W., I, 51, 56, 66, 67, 68. 69. 70, 71, 72, 75, 76, 77, 78 Freeh, F., I, 62 Friele, H, 305 Gagel, C, ... II, 223, 225, 231, 236, 250 Garnier, F., I, 266 Geinitz, H. B., . 150, 214, 217, 264, 267, 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 Goldfuss, A. 1,303,321, 333 Gosselet, J. H, 189 GouUl, A. A. I, 123 Graliolet, P I, 65 Gray, J. E I, 122; II, 340 Greene, T. A U, 199, 222, 249 Graenewaldt, ...... II, 231 GuilUer, A., . . . . . . I, 63 Gurley, W., I, 145; II, 174 Hall, 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, 165, 187, 188 192, 191, 195, 19li, 198, 199, 200, 201, 202, 205, 206, 208 209, 211, 2U, 230, 240, 215, 246, 249, 253, 254, 257. 261 261, 269, 272, 276, 277, 281, 284, 285, 290, 291, 295, 298 300, 303, 304, 310, 312, 314, 319, 321, 322, 323, 328 U, 1, 2, 3, 4, 5, 13, 13, 14, 15, 18, 21, 22, 23, 28, 40, 43 47, 51, 52, 54, 58, 59, 65, 06, 70, 73, 78, 79, 80, 83, 84 108, 109, 112, 115, 124, 127, 134, 136. 138, 142, 146, 154 161. 163. 164. 182, 185, 1S7, 189, 193, 195, 202, 204, 206 212, 215, 219. 223, 225, 231, 236, 2.U, 242, 249, 252, 253 261, 265, 277, 280, 293, 302 Hancock, A., . . . . . I, 4, 117, 148 Hartt, C. F., . . I, 98, 107, 120, 137, 188, 231, 232. 254 n, 23. 286, 291 Haughton. . . . . , . II. 2 PAGE. Hanpt I. 294 Ilayden, F. V,. . I, 3, 66, 120, 261, 264, 303, 304, 322 II, 2, 3, 51, 54, 80, 83, 120, 15 1, 293 Helmerscn, G.von, .... I, 319, 320 Herrick, C. L., . 1,3,9,121,133,189,209,254,201, 304 323, 328; II, 4, 5, 23, 43, 47, .50, 52, 84, 109, 169, 189 192,265, 286 Ilcrzer, II II, 97 Hicks, H I, 6 Hinde, G. J I, 188, 201; II, 58 Hisinger, W. von, . I, 200, 204, 276, 290, 303; II, 40, 103 185, 231 HoU, U. B., I, 6, 90 Iloernes II, 2S4 llolzaplel, E , II, 131 llowse II, 214 Ilusted, J. W II, 120 Huxley, T. II I, 1, 186 Hyatt, A. • . . . U, 65 Ives, J. C I. 266 Jaekcl, O I, 294 James, J. F. I, 8 James, U. P., . I. 3, 18, 19, 145, 188, 201, 205, 21,5, 276, 281 293; II, 154 Joubin, E I, 1, 147, 149 Kayser, E., I, 153, 211, 241, 242, 253, 259, 260, 2)-5, 286, 290 II, 33, 40 101, 112, 172, 175, 195, 196, 197, 216, 241 247, 260, 281, 282, 313, 315, 316 Keyee, C. R., . . ■ -I. 304, 3'23; H, 4, 84 Keyserling, A. von, .... I, 307, 317 Kiesow II, 200 King, C. I, 61; II, 228 King, W., . I, 2, 7, 10, 11, 13, 11, 18, 20, 21, 22, 30, 31, 33 34, 35, 36, 38. 40. 41, 43. 14, 45. 46, 48. 51, 51, 55, .67, 62 63, 146, 147, 119, 156, 186, 200, 201. 204, 211, 245, 248 219,251,252,267, 276,311.317, 319, 320,328, 339 II, 8, 47, 49, 50, 71, 87, 89, 91, 103, 195, 210, 214, 225 227, 282, 285, 293, 294, 322, 339 Klffiden, K. F. von, .... I, 276, 303 Koi-nig, . . . . . . . II, 8 Kouiuck, L. de, . 1,211,253,267,276,301,302,303,300, 314 317, 319, 321, 323, 325 333, 334; II, 9, 98, 119, 122 202. 203. 208, 265, 294, 296, 299, 314, 315 Kovvalevski, ..... II, 328, 330 Krotow, ......' I, 310 Kutorga, S., . I, 80, 82, 95, 101, 102, 103, 109, 110, 111, 112 113, 115, 116, 120, 123, 135, 136, 158, 160; II, 34 I.acaze-Duthiera, . . . I, 16 Lahusen, ....... I, 230 Lamarck, J. P. B. A. de M. de, I, 5, 120, 121, 122. 145, 321 Laube II, 103 Linck, I, 321 Lindstrom, G., . I, 33, 34, 36. 38, 201, 204, 241, 245, 274 II, 62, 67, 161, 185, 219, 231, 234, 241, 307, 322 Linnarsson, J. G. O., 1,86,91,94,97,98,99,101,107, 108 Linne, C, . . • I, 145, 150, 204, 213; II, 163, 231, 234 Slarcou, J., . I, 187, 208, 322; II, 2, 21, 22, S3, 120, 202 Marcy, O. I, 281; H, 241 Martin, W., . I, 211, 321; II, 33, 47, 202, 214, 216, 293 Mather, W , II, 1, 12, 21, 201 Matthew, G. F., • I, 56, 58, 69, 81, 91, 93, 99, 101, 102, 103 105, 107, 137, 183, 231, 232, '233; II, 326 M.-iurer, F., I, 259 INDEX. 373 PAGE. McChesney, J. H., . I, 120, 1S7, ISS.lOl, 196, 261, 262, 322 350; II, 2, 3, 12, 13, IS, 22, 51, SS, 83, S4, 120, 103 164, 203, 236, 23S, 277, 281, 293 McCoy, F., . . 1,55,85,129,153,153,187,200,201, 203 204, 211, 233, 245, 253, 261, 263, 276, 2S0, asi, 290, 298 303; II, 9, 21, 32, 33, 47, 02, S3, SI, S7, 89, 92 93, 134, 185, 193, 214, 249, 282, 293 Meek, F. B., I, 3, 33, 36, 56, 62, 64, 60, 90, 97, 101, 103, 120 127, 132, 135, 187, 188, 194, 196, 198, 201, 205, 208, 211 2U, 213, 217, 245, 250, 253, 254, 261, 267, 269, 272, 276 281, 284, 290, 295, 303, 304, 309, 322, 328; 11, 2, 3, 4 8, 15, 18, 22, 23, 28, 33, 43, 47, 49 50, 51, 5t, 38, 73 80, 83, S4, 120, 130, 151, 101, 161, 182, 193, 203, 204 215, 241, 249, 251, K2, 254, 261, 264, 277, 293, 302 311, 312 Michauci, A. L. G., . . . . I, 321 Mickwilz, A., ..... .1,337, 339 Miller, S. A,, . I, 3,8,133,115,188,194,196,198, 201 202, 205, 208, 245, 272, 276, 2S1, 295, 323; II, 4, 23, 26 2S, 151, 182, 185 Mallei-, V. von, ..... I, 95, 06, 102 Morris, J , ... I, 110, 135, 303; II, 136, 137 Morse, E S, . . . . . . 1, 8, 16 Morton, S. G., .... I, 321; II, 21, 16, 293 Muller, O. F I 122, 145, 160 Miinstcr, G. von, . . . . . I, 314 Munier Cli.almas, . . . . . I, 28, 298 Murchison, It. I., . . I, 56, 227, 328; II, 24, 108 NettelroUl, II., . 1,3,146,189,193,198,201,206,209, 211 251, 277, 285, 290, 301, 328; II, 5, 13, 13, IS, 23, 28, 40 43, 54, 59, 66, 73, 80, 84, 109, 124, 142, l.-|4, 164, 181, 182 183, 219, 231, 234, 235, 236, 242, 230, 263, 280, 294, 302 Neumajr, M. I, 301, 324 Xewberry, J. S., . .1,9, 2a, 266, 303, 322; II, 2, 22, 83 Nicholson, II. A., I, 3, 33, 36, 120, 138, 145, 188, 192 201,2.54, 2S5, 304, 328; II, 3, 13, 43, 58, 73, 193 Xoetling, F., .... 11,223,226,227, 229 Norwooil, J. G , . I, 303, 312, 321, 328, 332, 333; II, 2, 21, 51 Novak, O., 11,231, 235 CEhlert, D, r., . 1,23,153,203,209,210,233,241,243, 250 254, 261, 267, 269, 272, 277, 286, 287, 288, 289, 295, 302 310, 326, 333, 335; II, 54, 53, 50, 103, 104, 115, 182, 187 183, 196, 197, 198, 210, 215, 230, 241, 242, 244, 245, 232 254, 258, 203, 264, 265, 266, 272, 273, 277, 281, 305, 323 GMham, U , I, 29 Orbigny, A. d', . 1,120,12^,136,1,38,141,153,160,180, 214 217, 233, 234, 237, 245, 303, 321 ; II, 1, 16, 31, 83, 88 112,163,223,227,281, 307 Owen, D. D., . I, 2, 39, 187, 192, 200, 208, 225, 245, 201 284, 303, 321 ; II, I, 2, 21, 28, 163, 2) 1 Owen, R., ..... I, 2, 16, 186 I'an.ler, C. H., . 1,80,117,113,119,141,186,192,200, 221 233, 234, 235, 236, 237, 238, 250, 284, 295, 296, 297, 293 II, 225, 227 Parkinson, J., ...... I, 321 Phillips, J., . 1,2,6,13,201,211,245,253,250,237, 261 269, 278, 281, 303; II, 11, 40, 62, 89, 92, 93, 185, 193 200, 202, 204, 214, 216, 217, 265, 282, 294 Pilsbry, H. A I, 246 Poll, J. X., I, 145, 147 Potiez, V. L. v., . . . . . 1, 321 Poulson, C. A., . . . . . . I, 250 Pratten, 11., I, 303, 312,321,328,332,333; U,2,21,51, 101, 112 PAGE. Prout, H. A I, 321 Quenstedt, F. A., . 1,80,109,110,200,205,211, 219 241, 245, 267, 301; 11, 31, 31, 40, 58, 73, 88, 101, 102 113, 114, 174, 173, 178, 195, 196, 203, 231. 241, 245, 260 277, 281, 282, 283, 281, 283, 293 Baflnesque, C. S., I, 245, 216, 217, 24.S, 249. iV). 252 liamsay, A. C, . . . . I. 204 Itang, A. S., 1, S21 Ualhbun, K., . I, 3, 120, 188, 304, 328; II, 3, 4, 18, 43, 138 252,2.51, 302 Reeve, L. A I, 121 Retzius, A. J., . . . . I, 145, 150 Riclithofen, ...... II, 315 Riemau, P., ...... 1, 218 Rigaux, E., ...... I, 241 Ringueberg, E. N. S., . I, 3 120, 146, 189, 204, 205; II, 4, 13 Ra-raer, A. 11,40,231, 241 Uccmer, F., . I, 2, 187, 205, 276, 290, 30-2; II, 1, 2, 10, 21 31, 65, 16:i, 195, 211, 243, 255, 277, 282 Rogers, H. D., . I, 195, 201, 281, 2*1, 322; II, 2, 15, •22, 28 58, 73, 83, 97, 163, 255 Rominger, C, . II, 1.53, 206, 263, 272, 288 Rouault, M I, 36, 241; 11, 51, 66 Salter, J. W., 1,6,36,55,56,67,53,83,81,86,107, 153 158, 187, 192, 196, 201, 204, 241, 245, 269, 271, 284, 322 II, 62, 83, 1,36, 137, 138, 161, 10.3, 185, 195, 219, 249 307 Suudbeiger, G. ami F., . I, 233. II, 40, 112, 113, 129 130, 133, 195, 282, .302 Saideson, F. W., ..... II, 1.30 Safford, J. M., . . . 1,183,199,200,211, 341 Schauroth, K. F., . . . . . 1, 145, 150 Schenck, II, 141 Schiel, I, 321; II, 83 Schlotheim, E. von, I, 145, 155, 158, ISO, 200, 202, 211 213, 233, 253, 267; II, J 13, 163, 225, 227, 283 Schnur, S , I, 241, 253, 257, 259, 284, 30!; II, 31, 40 112, 129, 1.TO, 131, 172, 195, 282, 302 Schmidt, Fr. . I, 286, 290; II, 102, 195, 230, 241 Schuchert, C, . I, 25, 88, 112; II, 8, 47, 50, 51, 67, 150, 151 131, 157, 294. 297, 346 .Schumacher, I, 121, 1'22, 123 Secbach, K. von, . . . . . I, 101 Semenow, P I, 253, 293; II, 311, 312 Shaler, X. S., . I, 187, 189, 192, 196, 193, 208, 233, 216 276, 281, 288, 295; II, 3,83, 164, 219 Sharpe, I)., . 1,118,138,141,248,303,11,1,130, 137 225. 227 Shipley 11, .330 Shepard, C. U. I, 321 Shura.ard, R. F., 1,3,120,145,187,303,319,321, 322 H, 1, 2, 21, 28, «, 47,51, 83, 103, 193, 202, 21t, 215, 293 Simpson, G. B., . I, 189, 209, 301; II, 43, 47, 50, 73 Sowerby, J., I, 120, 121, 122, 150, 156, 153, 192, 203 204, 211, 227, 245, 253, 270, 231, 290, 317, 321, 328 II, 1, 7, 8, 24, 47, 134, 103. 178, 185, 195, 199, 202, 231 236, 237, 282, 293 Sowerby, J do C, . I, 121, 270; II, 6>, 195, 202, 219, 236 237,241, 219 Spencer, J. W., . . . . . . I, 146 St. John, O., . . I, 145,264, 314; U, 293, 300, 301, 302 Steininger, . . . . . n, 101 Steinmann, G., • . . . . . II, 141 374 INDEX. Stevens, . I, 303 Stob(Eus, K., I, 145 Stoliczka, F., I. 29 Stubel, n. 141 Suess, E., . II, 70,^03, 129, 133, 178, 277, 278, 279, 283, 285 Swainson, 11, 138 Swallow, G. C, . I, 187, 208, 264, 281,322, 328; 11, 2, 3, IS 22, 43, 47, SO, 83, 119, 120, 215, 263, 293 Swinton, F. S., . I, 318 Toula, F., . II, 3, 81, 293 Tschernyschew, Th., I, 241, 243; II, 25, 34, 78, 172, 175 170, 210 TrautschoUl, H. von. I, 214 Troost, II, 47 Tryon, G. W., . I, 240 Ulrich, A., . II. 130,138, 141, 302 Ulricli, E. 0., . I, 24, 25, 27, 33, 53, 87, 88, 89, 112, 120 138, 118, 188, 194, 295; II, 154, 193, 231 Ure, D., . I, 303, 331 Vauuxem, L., I, 2, 120, 186, 205, 211, 253, 257, 258, 276 281, 281, 290, 303,328; II, 1,12,11,17,21,53,73, 163 19,!, 195, 204, 253, 255 Verneiiil, 1]. de, . I, 110, 111, 141, 151, 191, 200, 201, 204, 214 219, 233, 233, 215, 253, 250, 204, 2liG, 209, 276, 280, 283 297, 298, SflO 301, 303, 317, 319, S31, 3-'3, 325, 328, 333 11, 1, 11, 2t , 67, 101, 103, 104, 112, 131, 138, ICl, 172 178, 195, 202 210, 211, 225, 227, 223, 231,236, 211, 242 249, 277, 278, 279, 2S2, 293, 302 VercliSre, . 11, 98 Verworn, . I, 15S Volborth, A. von. 1,73,82, 83 Waagen, W., I, 28, 29, 30, 84, 69, 90, 94, 95, 118, 147 151, 210, 214 215, 216, 217, 239, 254, 256, 201, 202, 263 261, 205, 267 208, 304, 306, 307, 308, 310, 313, 316, 317 319, 320, 324 335, 3'6, 330, 331, 332; II, 9, 21, 26 34 91, 98, 99, 15, 119, 131, 122, 123, 107, 182, 196, 197 208, 209,5215 260, 265, 267, 272, 274, 293, 294, 295, 296 298, 299, 300 301, 302, 313, 314, 315, 316, 319, 322, 323 326, 334, 336, 310, 343 Wahlenberg, . II, 40, 103, 195 Waller, . I, 145 Warth, H., I, SO Walch,J. E. J., . I, 321 PAGE. Walcott, C. U., . I, 3, 9, 56, ,57, 58, 66, 67, 08, 69, 70, 71, 72 75, 78, 91, 93, 97, 98, 99, 100, 101, 102, 103, 101, 105, 106 107, 111, 113, 114, 110, 117, 121, 137. 110, 155, 188, IS9 193, 194, 198, 206, 211, 230, 331, 232, 311, 243, 210, 254 269, 278, 285, 290, 301, 311, 828, 333; II, 4, 15, 18, 23 28, 33, 43, 47, 50, 53, 73, 84, 130, I24,'127, 113, 161, -189 193, 200, 203, 319, 231, 212, 286, 294, 321 ■W'aldlicim, G. F. de, . I, 191,214,215, 264, 266, 275; H, 202 Wendt, A. F., II, 275 WenjidioCr, Y I, 259 White, C. A., 1,3,90,98,101,120,121,145,116, 187 188, 193, 190, 198, 201, 200, 208, 299, 211, 215, 253, 264 277, 281, 285, 304, 314, 322, 323; II, 2, 3, 13, 14, 18, 22 23,28,43,47,51,52,51,83,112,119,130, 113, 161, 263 210, 215, 249, 350, 293 Whiteaves, J. F., . -1,3, 37, 40, 44. 45, 46, 66, 113 115, 244, 293, 314; II, 5, 13, 15, 23, 103, 200, 231, 242 201, 264, 383, 285, 810 Whitfk-ld, R. P., . . I, 3, 11, 30, 48, 57, 69, 61, 02, 66 69, 120, 187, 188, 189, 195, 193, 206, 203, 209, 211, 218, 230 233, 239, 240, 215, 246, 253, 354, 269, 277, 281, 285, 804 310, 311, 333, 333; II, 2, 3, 4,13, 15, IS, 23, 28, 40, 51 59, 05, 77, 84, 89, 113, 115, 113, 164, 174, 175, 193, 195 212, 313, 214, 210, 225, 231, 236, 23!), 210, 241, 242, 249 250, 275, 276, 2S6, 293 Wilckcns, C. F. I, 270, 279 Williams, II. S., . . I, 3; II, 4, 5, 33, 196, 203, 271, 317 WinchcU, A., . I, 3, 63, 64, 120, 145, 153, 187, 188, 208 211, 253, 284, 301, 314, 332, 328; II, 2, 3, 8, 15, 23, 47 50, 51, 73, 83, 108, 124, 1S9, 193, 313, 241, 265, 267, 371, 286 Winchell, N. II., . . I, 3, 69, 62, H5,[188, 194, 195 206, 281 ; II, 150, 151, 154, 157 Woodward, S. 1"., . . . I, 66 Woolson, U, 183 Worthen, A. H., . 1,3,36,63,64,120,121,188, 253 361, 276, 281, 290, 30!, 309, 322, 328; II, 2, 5, 16, 18, 22 23, 28, 33, 43, 47, 73, 83, 84, 136, 161, 164, 204, 2!5, 241 249, 251 , 252, 254, 302, 31 1 , 312 Wynne, . . .... I, 29 Tiindell, L. P I, 187; 11, 1, 28, 47, 163 Young, J., . . I, 307; II, 10, 20, 30, 93, 307, 309 Zittel, K. A. von, . I, 134, 272, 295, 308; II, 115, 178 Zugmayer, II., . . I, 293; II, 45, 73, 87, 96, 313, 314 II. Register of Genera. (Names in italics are synonyms; figures in full-face type denote place of description.) PIGE. PAGE. Acambona, . II, 105, J IS, 119 Amphistropbia, . I, !892; U, 33il Acritis^ I, SO, 83 Anabaia . II, 141 Acrothele, I, 70, 98, 99, 100, 102, 103, 108, 113, 114 Anastrophia, 11,219 233, 225 2-27, 228, 233, 239, 249, .341 107, 168; II, 324 Anazyga, . . II, 154, 156 Acrolliele?, . I, 101 Ancistrocrania, I, 149 Acrotreta, . I, 68, 93, 65, 96. 99, 100, 101, 103, 104, 105 Anisactinella, II, 103 106, 108,109, 113, 114, 166, 167, 168; 11, 321 Anomactinella, 11, 103 Acrotreta, . I, 95, 105 Anomia^ I, 145, 2 1, 331; II, 40, 47, 163, 315 Actiuoconchus, II, 93 Anomites, ■ I, 233,376,321; I(, 163, 195 Ambocoilia, I, 92; II, 2, 54, 55, 56 ^Vnoplia, . I, 309 AmiJhiclina, I, 302; II, 103, 315 Anoplotheca, I, 220, 303 II, 1!S9, 133, 134, 137, 139 Amphigenia, . II, 233, 251, 858, 253, 257, 200, 261,263, 263 142,144, 345 264, 311, 342, 349 A ntirhynchmiella^ II, 231, 242, 244, 245 INDEX. 375 PAGE. 1 I' ACE. ArhiisciditeSt I, 321 Christiania, I, 298 Area, I, 321 Cistclla, . . 11,305,3-28, 330 Argiope, II. 328 Claca^etla, I, 321, 333 Athyris, . H, 11, 83, 8."), 86, 88, 89, 91, 92, 93, 94, 97, 98, 100 Clinlonclla, 11, 169 118, 1-21 111, 291, 317,334, 313 Cliothyris, 11,89, 91 AthyriSf U, 2, 3, 63, 65, 73, 78, 85. 98, 121, 134, 328 Clilambonitus, . 218, 219, 230, 231, 232, 233, 231, '230, 237 Atrypa, I, 207, 298; II, 89, 131, 1«3, 171, 173, 174 239, 240, 243, ,340; 11, 327, 328, 332, 333, 336, 341 175, 176 Clorlntia, 11, 241 Atrifpa, I, 187, 200, 269; II, 58, 62, 65, 73, 78, 80 Ccelospiia, 11, 134, 136, 137, 140, 144, 160, 839, 345 83, 87, 101, lOS, 124, 127, 136, 142, 152, 154, 101, 180 Calospira, II, 161, 162 18,1, 189 193, 195, 202, 204, 214, 219 241, 249, 255, 293 Conchidium, II, 210, 230, 231, 234, 235, 236, 210, 261 307, 328, 338 334, :!36, 311 Atrypina, . . ,U, 153,101,171, 171 Conrhius, . I, 276 Aulacorhpiclius, 11, 72, 311, 312, 335 Conchyliolithus, 11,47,202,214, 293 Aulonoti-eta, I, 8'i, 337 Conocephalites, I, 30 Aulonotreta, 1, 80 {Conradia,] I, 39 Aulosteges. . I, 316, 319. 330; U, 329, 340 Cranajna, II,2»», 301 Aulo&teges, . I, 314 Crania, . ] , 1, 108, 122, 141, 145, 147, 149, 150, 151, 152 Avicula, I, 06 153, 164. 155, 156, 157, 158, 169, 170; II, 3i5 Bida, Goldfuss, , A. venusta, Schnur, Anoplia nuoleata, Hall, Athyris acutomarginata, Wmtgen, A. ambigua, Sowerby, A. Americana, Swallow. A. Angelica, Hall, A. Anticostiensis, Billings, A. Sluncha, DiUings, A. borealis, iJillirigs, A. capillata, Wani;en, A. concentrica, von Buck, A. cora, Hall, A. TJawsoni, sp. nov., A. dcnsa, sp. nov , A. globulina, Waagen, A. llannibalensis, SuxUlow, A. Harpalyee. JillUngs, A. Headi, Killings, . A. hirsuta. Hall, . A. iucrassata, Hail, A. Junta, Billings, . A. lamcllosa, Leveille, A. Lara, Billings, . ..-1. Jilaia, Billings, . A. oxycolpus, Emmrickf . A. peetznifera, Sowcrhij, . A. planosulcata, Philitp.%, A. Priustana, IJillings, A. Uogci-si, sp. nov., A. Koyssii, Leveille,. A. semiconcava. Waa^en. A- spirifcroide.^, Eaton, . A. subcxpansa, Itnn^n, . A. sublamellosa, Halt, A. sabquadrata. Hail, A. subtilita. Hall, . A. sp., A. trinuelea, Hall, . A. uynbonata, Billings, A. vittata. Hall PAGE. II, 7 II, 132, 133, 136 11, 133, 136 . 11, 339 • 11, 91 II, 93, 97 n. 91 u. 90 II, 158, 159 . U. 68 11, 158, 159 II, 91 II. SJ. 90 II, 90 11, 95, 9C, 118 II, 361 II. 91 u. 90 n, GO II, 157, 159 n. 91 II, 90 II, 62 II, 90 . II. 149 • II, 34 II, 96 II, 88, 91 .11. 91, 99 II, 64 II, 97 II. 91 11, 91 II, 89 II. 91 II, 91 II, 9.5, 96 II, 86, 95, 97, 99 II, 97 II, '.ll. 96 II, 64 II, 89, 90 380 INDEX. PAGE. 1 PAGE. Atrypa ? apicutata, Salter, I. 270 Atri/pa uitisulcata, Conrad, n, 80, 81 A. (uutoplicata, Courad, . II. 130 A. (Trii)lecia) apieulata, Salter, I, 271 A. altilis, Uall, II, 181 A. (T. 1 incerta, Davidson, I. 271 A. amygdala, CaiUaud, II, 26», 281 A try pi la Clintoncnsis, sp. nov.. II, 161, 162 A. aprinis, de Vei-neuil, . II, 111 A disparilis. Hall, II, 162, 171 A. araia, Conrad, . II, 215 A. imbricata. Hall, 11, 102, 171 A. aspera, Sclitotheim, . 11, 170, 171, 172 Aulacorliynchus Pacliti, Dittmar, . ; II, 312 A. aspera, var. occidcntalis, Hall, II, 170 Aulonotreta polita, Kiitorga, . . I, 80, 82 A. BaTTondii, Davidson, . H, 162 A. eculpta, Kutorga, I, 82 A. bisulcala, Emmons, II, 62, 116, 148, 151 Aulosteges Dalhousii, Davidson,. I, 320 A. Calvini, Natdroth, II, 173 A. Guadaloupensis, Shumaratulata. Meek and Worthen I, 12, 63, 164 A. Deshayesi, CaiilauJ, . II, 201, 281 lieeeli iria Davidsoni, sp. nov.. 11, 300 .4. didyma, Dalman, II, 60 1!. subhevis, Waagen, II, 300 A. diibia. Hall, II, 160, 181 liillda cpida, Gold/uss, U, 98, 131, 133 A. elllpsoidea, Ntttelroth, II, 169 Uracil prion genii'ulatum, Slialer, . I, 288 A. exigita, Hall, . II, 14S), 150, 151 15. Leda, Billings, . . . . I, 288 A. extatis, Emmons, I, 270 li. venti-icosum, Slialer, . I, 288 A. galeata, Dalman, 11. 212 Brauconia boruysica, Gagd, . II, 223 A. heiniplicata. Hall, II, 221, 222 Calceola heterod ita, Dcfraiice, . II, 41, 44 A. hemisplurrka. Hall, u, 136 Camarella ? auliiiuata, Walntt. 11, 221 A. hirsuta. Hall, II, 127 0. caloifera, Billings, 270, 271 ; II, 214 A. hystrix. Hall, . II, 172 c. hemiplicata. Hall, 11, 222 A. imbricata, Soicerby, II, 173 c? minor, WnUuti, . 11, 221, 311 A. ? incerta, Davidson, I, 270 c. l^anden, Billings, U, 220 A. i)Wr»afrt, d'Ol-bigny, . , II, 203, 281 c. Volborthi, Billings, . . II, 219, 220, 221, 225 A. intermedia, Hall, H, 60 Cainarium typitm. Hall, .11.71, 72 A. interpUcata, Sowerby, . II, 224 Camaroi»horia bisulcata, Shtimard, . . n, 217 A. leTis, Sowerby, . II, 251 C. caput-tcstudinis, White, . n, 217 A. lepida, Davidson, II, 131 C. Dawsoniana, Davidson, . II, 217 A. marginalis, Dalman, . . II, 172, 17:f, 174 C. eucliaris. Hall, . II, 82, 217 A medialis, Vanuxcm, 11, 205 0. Giflbrdi, Worthen, II, 217 A. modesta (Say), Hall, II, 155 C. globulina, Phillips, . u, 216 A. muUuosta, Hall, 11, 76 C. globidina, Davidson, II, 217 A. Murchisoniana, 11, 171 C. ■ Iliimbletonensis, Hmvse, II, 217 A. navilbrmis, Hall, II, 60, 75, 77 c. isorhyucha, 3IcCoy, H, 217 J, nitida. Hall, H, 69, 60 c. lenticularis. White and Whitjidd, II, 218 A. iiitida, var oblata, , II, 60 c. rhomboidalis, sp. nov. II, 217 A. nodostriata. Hall, II, 170, 173 c. ringens. Swallow, II 217 .1. nucella, Dalman, II, 230 c. Schlothoimi, roji Bticb, II. 217 A. nudeus. Hall, . I, 270 c. Swalloiana, Shumard, . II, 217 A. oblata. Hall, . II, 60 c. Swfdluviana, Shumard, II, 253 A. obovata, Sowerby, II, 152 c. subcuncata. Hall, II, 217 A. palmata, Morris and Shai-pe, II, 137 0. subtrigona. Meek and Worthen, II, 217 A. ;)ec(i;j(/W-tt, Sowerby, . II, 00 Camaros])ira cucharis, Hall, . II, 82 A. planoconvexa. Hall, II, 136 Capellinia niira, sp nov , II, 248 A. plena, Hall, . II, 181 Cardinocrania indica, Waagen, I, 164 A. plicatula. Hall. . II, 130 Cataz; ■ga Heacli, Billings, II, 158 A. prunum, Dalman, II, 61 CentTOmlla Alii, A "Winchell, . II, 290 A. pscndomargmalis. Hall, II, 173 C. alveata. Hall, II, 208 A. quadricosta. Hall, II, 76 C. Amia, Hartt, II, 291 A. reticularis, Linne, . II, 163, 165, 167, ir.S, 109, 170 C. Bergeroni, (Ehlert, II, 266, 272 ni, 172, 173, 174, 175, 217 C. Gaudryi, (Ehlert, 11, 266, 272 A. rugosa. Hall, U, 170, 171 C. glansi'agea. Hall, . . I] , 267, 268, 269, 273 A. seitula. Hall, U, 79 C. Glaucia, Hall, . . II, 269 A. spinosa, Hall, . U, 172 C. Oaerangeri, II, 373 A. tumida, Dalman, U, 67, 76 c. Hecate, Billings, II, 268 INDEX. 381 Centronella impressa, Hull, . C. Juiia, A. WilK^liolI, . II, 25S, 267, C. ? Margariilii, Dnhtj, C. virgo, Phillips, . Charionella Circo, Billings, C. > Hyale, Billings, . ChorietcUa nasuta, ^Vaa^en, Chonctes Autiopia, 7j»(7/(n^s, , C. Cauatlensis, Billings, . C, complaiiata. Hall, , C. concentrica, de Konimk, C. cornuta, Hall, . C. coronata, Cdnuut, C. Dawsoni, Killings, C. Fisclieri, Nor\vO(jtI antl I'ratten, C. glabra, Geinitz, C. l I, Ii . I, K5, I< I, 150, II, I. li 121 148 151 87 ISl 151 S25 Ui 121 150 146 148 152 153 325 153 181 Cyitia alia, Hall,. C, cj-rtinifonnis. Hall and WhiiJieU. C. exporrecta, Watdenberg, C. exporrecta, WaJUenAers, var. arree Whitfield, C. gigas, Troost, C. Murat, C. dorsata, McCoy, C. Ilamiltonensis, Halt, . C. lachrj-mosa, sp. nov., C. pyramidalis. Halt, C. roslrata, Hall, . C. septosa, Phillips, C. trupietra, ]Ialt, C. nnibonata. Hall, C. umUonata, var. Alpeuensis, var. nnv.. I, I, • I, I, 141^, 149, I, l.')3 ; II, li I. 153, II, 301, 302 II, 291 H, 2S8 II, 2S6, 288 . II, 283 U, 287, 289, 290 . II, 288 II, 209 II, 147, 1(8, 149, I5S 2SU, 345 U, 43 II, 42 II, 41, 43 U\, Hall and II, 42 II, 51 II, 41, 42 11, 42 II, 43, 362 II, II, 11, H, II, • H, . 11, 11, II, II, II, 46, 362 II, 46 11, 44, 46 II, 46 II, 46 II, 46 II, 369 382 INDEX. Cyrtotheea Ampezzana, Bittmr, Davidsonia Bouchard iuna, tfe Koninck. B. Verncuili, Bouchard^ . Btividsonella Ihig^iloifJes^ Waaj^en, D. (=;l.akhmina) linguloides, Waagen. Dayia navicula, Soiverhy^ GelthijTis ulerata^ Dalman, Devbya alUnis, sp. nov. D. Bcnnetti, sp. nov., D. biloba, sp. nov., D. Broadlieadi, sp. nov., C. Correana, Berby^ D. ? costatula, sp. nov., D. cvassa. Meek and Hnyfen, D, grantlis, Waagen^ D. Keokuk, Hall, . D. regularis, Waagen, D. robusta, Hall, . D, rugiuosa, sp. nov., Dielasnia bovidcns, Morton, . D. clongatum, Srlilotheim, D. lurgidum, Hall, Biela.sinina plicata, Waagen, . Dinobolus lioheraicus, Barrn/ule, D. Brimonti, Rouault, D. Canadensis, Billings, . D. Com-adi, Hall, . . I, 3S, 39, 40, D. Hicksi, Davidson, D. magniJicus, Billings, . D. parvus, Whitjiild, D. .SehmidU, Davidson and iTing D. ti'ansversus, Salter, B. M'oodwardi, Salter, . Bioi'istella indistincta, Beyrich, Biplos'pirella Wissmanni, Miin,!«er, Discina acadiva, Hai'tt, D. ainpla. Hall, D. .' Baidetchensis, Bavidson, D. Boliemica, Barrande, . D. Caerfaiensis, Hicks, D. Clara, Spencer, . D. Conraii, Hall 2). discus. Hall, D. ZIoria,- Hall, D, grandis, Vanuxem, D. humilis. Hall, . D. Herzeri, sp. nov., D. intermedia, Barrande, . D. tnutilis. Hall, D. lamellosa, Eroderip, . D. Lodensis, Hall, . D. Maotis, Barrande, D. Manhattanensis, Meek and AV D. margimilis, M'hitfield,. D. inedia. Hall, B. viinnta, Hall, D. Morrisi, Bavidson, D. Neicherryi, Hall, D, nitida, Phillips, D. ostraoides Lamarck, B. pileolus. Hicks, . B. pleurites, Meek, B. Randalli, Hall, . PAGE, II, 45 302 302 89 J I I I, 28 II, 63 11, 9 I, 349, 350 I, 263, 348 I, 350 I, 263; 346, 3*7 I, 2G3 I, 346 I, 2C3 I, 262 I, 262 I, 262 I, 263 I, 34G II, 295, 301 II, 295 II, 297, 298, 317 II, 298, 299 I, 39 I, 39 I, 39 , 42, 43, 175, 176 I, 39 1, 39 I, 39, 40 I, 39, . I, 39, . I, 39, . 11, II, I, 40 40 40 100 102 137 1, 125, 127, 130 I, 79 I, 127 I, 137 I, 125 I, 125, 130 1, 126, 132 I, 125 I, 125, 136 I, 125 I, 127, 131 I, 135 I, 137 I, 122, 123 I, 125 I, 127 1, 125 I, 125, 127 I, 125, 133 I, 125, 131 I, 129 I, 125, 130 I, 125, 126, 131 I, 121, 122 I, 137 I, 125, 131, 132 I, 125 Biscina rcversa, Barrande, B. rtigata, Barrande, B. secedcns, Barrande, B. striata, Schumacher B. striata, Sowerby, B. tarda, Barrande, B. tenuilamellata, Hall, B. tritucata, Hall, . B. ((Ehlertella) pleurites. Meek. Biscinisca lamellosa, Broderip, Biscinolepis gran'ulata, Waagen, Biscinopsis Guliclmi, Matthew, Bouvillina Dutertrii, Murchison, Kalonia eminens, Hall, E. medialis, Vannzem, E. peculiaris, Conrad, E. pumila. Hall, E. singularis, Vanuxem, E. sinuata, Hall, . E. Whitfleldi, Hall, Elkania desiderata, Billings, Enteletes ferrugineus, Waagen, E. hemiplicatiis. Hall, E. Lamarcki, Fischer de Wnldheim, E. pentaraeroides, Waagen, Euinetria graiuticosta, E. iiulica, Waagen, E, punctulifera, E. vera. Hall, E. vera, var. costata. Hall, E. Verneuiliana, Hall, . Eunella simulator. Hall, E. SulUvanti, Hall, Glassia elongata, Bavidson G. obovata, Soiverby, G. Romingeri, sp. nov., . G. AVhldbornii. Bavidson, Glottidia Audebardi, Broderip, G. Pahneri, Ball, . Gonarabonites lata, Pander, . Gruenewaldtia latilinguis, Svhnur, . 'Gypidia conchidiiivi, Balman Gj'piduia comis, Owen, . G. laiviuscula. Hall, G. Lotis, Walcott, . G. mundula, Calvin, G. Bomingeri, sj), nov., . G. subglobosa. Meek and Worihen, G. nngui/oTtnis, Ulrich, Halhna Nicolleti, Winchell and Scliuchert, II. Saflbrdi, Wtnrliell and Schuchert, Harttina Anna, Hartt, . Ilemiprouites alta, Pander, H. Americana, AVhitlield, . H. apicalis, \\niitlield, H. nutans, James, H. sphiBrica, Pander, H. tumida. Pander, Hemiptychina Himalayensis, Davidson, H. subhevis, Waagen, Hipparionyz consimilarts, Vanuxem, . H, constmilis, Vanuxem, , PAGE. I, 133, 135 I, 135 I, 101 , 122, 123, 135 I, 122 I, 135 I, 12S I, 87 I, 140 , 131, 133, 136 I, 90 I, 106 I, 289 II, 206 II, 206 U, 206 II, 206 1,2 I, 2 11,1 206 206 206 77 11, n, n, 1, I, 216 16, 217, 226 14, 215, 226 U, 12 I, 216 II, 122 II, 122 U, 121 I, 119, 120 II, 119 7, 120, 122 II, 290 II, 290 II, 153 I, 182, 153 II, 153 II, 153 I, I, H, 8 63 I, 237 II, 175 II, 231 , 242, 248 , 242, 248 II, 248 II, 248 II, 248 II, 248 II, 235 , 150, 151 , 150, 151 H, 292 I, 238 1, 239 I, 239, 240 I, 251, 345 I, 233 I, 238 II, 29>J II, 299 I, 253 I, 258 INDEX. 383 OAfiE. Hippanonyx proximus, Vanu:rtm, . . I, 257, 268, 259 Lept Tjnisca adnasccns, sp. nov., PAGE. I, 301, .•«K2 H. stmilaris, \anuxem, . I, 258 L. conca\a, Hall, . I, 301 332 Hustedia grandicosta, Davidsim^ . II, 122 L. tangens, sp. nov.. I, 301, H. 3Iormoni, Mareoii, 11, 121, 122 Lept j;nulopsi3 simplex, Hauvt, I, 2&t Hyattelia congeyta, Conrad., . II, IGO Leptobolus insignis. Hall, . 1, 73, 74 H. junia, Bulings, . . 11, 160 L. lepis. Hall, I, 7.t, 71, 75 Iphidea bclla, Billings, . . I, 97, 98 L. occi.lcns. Hall, I, 73 134 I. ornatella, Limiarsson, . . I, 97, 93 LeptoctBlia concava, Halt, 11, /. (-'.') ^culptilis, Jleek, . I, 94, 97 L. dichotoma, llatl. II, 137 Isogramma millepunctata, Jlfcei- anil IV'crf/it/i, . II, 312 L. limbriata. Hall, II, 137 Kutoi gina cingulata, Eillinss, . I, 117, 91, 02, 93, 94 L. llaliellitos, Conrad, . 11, 13 6, 137, l:i8, IIU, 111, 142 95 ; II, 326, 327 L. htinispltcnica, Davidson, .11, l.'Mi K. cingulata \ar. jiu^illa, Linnarsson, . . I, 94 1-. palmata. Sailer, II, 140 K. Labradorica, Billings, . I, 92, 9t ; 11, 321, 326 L. iinbricata, Ilall, . II, 162 K. Latourcusis, Mattheu;. I, 92, 93, 91, 95, 233; 11, 326 Leptadus Ricluhofcni, Kavser, , II, 313 K. miuutissiina, Hull and WldtfieU, . . 1, 94, 97 l.iml -tra-mella asTiidium, sp. nov , I, 134, 1»S K. paimula. White, . . .1, 92, 94, 95 I.ingula acuminata, Conrad, . I, 6 K. I'rospcctensis, Walcott, . I, 92, 94 L. a.'(iualis. Hall, . I, 9 K. (') ptei-ineoides, Matth'u; • I, 94 L. albida, Hinds, , . I, 13, l< K. sculptilis. Meek, . I, 92, 94 L. alveata.Hall, • 1, 14, 15 K. Whitlkddi, Walmit, . I, 92, 91 ; H, 326 I.. anipla, Ourn, , G Jvarpo nskia conjugula, Tsrherttysrheu . II, 176 L. anatina, Lamarck, . I, 4, 5, (i, 7, 8, 10, 11, 13 Jva3-seria lens, Phillips, . u, 102 17, 21, 2 2, S2, 49, 01, 53, 57, 60 Lacazclla mciliterranea, H, 333, 329 I,. attenuata, Sowerby, I, .">, 8, 11 Lakhmina liuguloides. Wuagen, I, 29 1,. Canadensis, Billings, . I, 24 27 Leptana aiii^nm, de Venieuil, I, 300 1.. centrilnieata. Hall, . I, 13 L. alteriiatd, Conrad, I, 248, 2S(1, 282, 283 1.. compta, sp. nov., 1. 171 L. alternistriata, Hall, I, 282 1.. Covingtoncnsis, Hall anil \V hitfitld, I, 8 L. analoga, Phillip.s, I, 279 I.. Criei, Davidson, 1, 63 L. asella, de Verneuil, I, 263 I.. cruniciui, Pliilllps, . I, 5, 13 L. caudata, Schnur, I, 287 L. euneala, Conrad, I, 1;, 12, 15 L. roncava, Hall, . I, 300 I.. DajjUno, Billings, I, 6 L. cnnvexa, I'andei-, I, 297 L. Davidsoni, Barrande, . I, 61 L. decipiens, Hillings, I, 294, 298 L. Bavisi, ^IcCoy, . I, 57 L deltoidea, Conrad, I, 2S2, 283 I.. densa. Hall, I, 9, 13, 171 L. demissa, Conrad, 1, 286 I-. Delia, JIall, I, 13 L. depressa, 8owcrby, I, 260, 279 1.. distilli^ta, Barranile I, IS L. eugli/pha, Dalman, I, 279, 296 I.. Elderi, Whitfield, . I. 9, 11, 12, 48 L. Dutertrii, Murcllison, . I, 288 L. epimia, Barrande, 1, 18 L. fasciata, Hall, . I, 282 L. I'eistmanteti, Barrande, I, 68 L. filitescta. Hall, . I, 251 I,. llabelUda, sp. nov., I, 6, 15, 172 L. immssnta. Hall (Saflord), I, 282 I,. granulata, Phillips, . I, IS, 27 L. laticosia, Conrad, . n. 306 L. Hairkii, Kouault, • I, «, 15 I.. Hasina, Bouchard, . I, 298 h. insons, Barrande, I, 64 L. Llandeiloensis, Davidson, I, 294 1,. Iowcnsis,,Ojct7i, I, 8 L. Moorii, Davidson, . I, 298 L. lamcllala. Halt, I, 10, 12, 16, IS, 48 L. muUirugata, McCoy, . . I, 279 L. I.eaMia, Hall, . I, R L. nodulosa, Phillips, I, 279 L? Leseuri, Rouault, I, 7, 9, 14, 63, 65, 16 1 L. ? nudeata. Hall, . I, 308, 309 L. Lewisi, Sou-trby, I, 10 i. oblonga, de Verneuil, . I, 300 I-. linguata, sp nov., 1, 173 L. obscura, llall. 1, 283 L. Malthewi, llartt, I, 100 L. plicotis, McCoy, I, 279 L. Melie, Hall, I, lU 11, 12 L. planumbona. Hall, . I, 247, 250, 251 L. raerabranacea, .4 Winchell, . I, 61 L. rhomboidalis, Wilckens, I, 250, 279, 280, 282 L. Mosia, Hall, I, 6 280, 287 , 29G ; II, 170, 184, 339 L. Nurwoodi, James, . 1,8, 19 L. rugosa, llisinger. I, 279 L. paliformis. Halt, • 1,59, 61 L. semiovalis, McCoy, . I, 279 L. paraclctus, sp nov., . I, 40, 12, 172 L. sordida, Billings, 1, 293, 29S L. perovata. Hall, I, « L. subqiiadrata, Hall, I, 299, 350 L petalon, llicts. I, 6 L. tenuicincta, McCo}', I, 300 L. pinnijormis, Owen, . I, 59 L. transversalis, Dalman, . I, 297, 296, 299 L! liolita. Hall, . I, 67, 72 L. unicostata. Meek and Wonhen, . . I, 282 L. prima, (Conrad) Hall, I, 69 L. Waltoni, Davidson, I. 283 L. Proc.teri, UMch, . I, in, 12, 15 384 INDEX PAGE 1 PAGE. XAngula plunibea-t Salter, .... I, 83 Magellania venosa, Salander, . II, 305 L. punctat.a, Hall, . I, 10, 11, 12, IS, 17, 43 Margiuilora ornata, Waagen, I, 331 L. ])ygm.Til, Salter, .... I, 6 M. t.\-pica, Waagen, I, 330, 331 L. pyramidata, .Stimixson, I, 8 Martinia scmiplana, Waagen, II, 34, 40 L. quadrat.i, Hall, . . . . I, 14 Martiniopsis inllata, Waagen, II, 10, 32, 34, 40 L lioinil'onnis. Halt, I, 6, 8 ]\r. subpentagonalis, Waagen, . II, 34, 40 L. Kouaulti, Salnr, . . . . I, 6 Mcgalanteris inornata. II, 263, 264 L. Scotica, Daviitson, . . . 1 , 6, 9, 15 M. ovalis. Hall, . II, 277, 280 L. .scutella, .sp. nov., . . . . I, 171 M. Archiaci, de Vermuil II, 278, 279, 280, 281 L. spathata, Hall, . . . • I, 18 Meganteris ovalis. Hall, . II, 280 L. Bpatiosa, i/a«, . . . . I, 6 M. ? Vicaryi, Davidson, . II, 281 I,. squamosa, HoH, . . . ■ I, B Merista elongala, Hall, . II, 71 L, sitbspaUilata, Meek and Worthcn, . I, 03 M. hcrculea, Barrande, . 11, 70, 71, 76, 77 L. teniola, sp. nov., . . . . I, 18, 173 M. ? naviforniis. Hall, II, 75 L. tenuigranulata, HfrCatj, I, 18, 27 M. passer, Barrande, . H, 70 L. Vanliornil, Miller, . . . . I, 8 M. plobcia, Sowerby, II, 71j 72 L. Waverliensis, llerriek, , . ; I, 9 M. prunulum, Schnur. II, 73 L. Whitii, Walcoti, . . . I, a, 11, 12, 48 M. scalprum, Roemer, II, 71, 72 L. Winona, Hall, . . . . I, 6 JI. Tennesseensis, sp. nov., . II, 71, 77, 365 L. zebra, Barrande, . . . . I, 18 M. typa. Hall, . II, 71 L. (Glottidia) Audcbardi, Broderrp, . 1,8, 163 Meristeila arena t:i. Hall, . II, 76 Lingulasma Sclmchcrti, Ulrirh, 1,24, 27 M. Barrisi, Hall, . . II, 78 Lingulella ca'lata. Hall, . .1, .57, 58, 69 M. bclln, Hall, II, 76, 78 L. Cineinnatiensis, Hall anil Whitlicld, I, m 51. cylindrii'a. Hall, II, 76 L. Davisi, McCoy, . . . . I, 66, 67 31. didi/ma, Dalman, . II, 60 "L. Dawsoni, Matthew, . . . . I, 58 jr. Dons, Hall, . II, 78 L. Ella, //afi and Whkjida, 1,67, 58 M. llaskinsi, Hall, II, 78 L. ferruginca, Salter, I, 58 M. Hougbtoni, A. Winchell, II, 78 L. (iranvillcnsis, Watcoti, I, 68 M. liuvis. Hall, 11, 75, 76, 77, 78 L. lowensis, Owen, ... I , 8, 14, 59 M. lata, Hall, II, 78, 80 L. lepis, Salter, .... i, 58 M. lens, A, Winchell, . II, 78 Lingulepis antiqua, Hall, I> 61 M. lenta, Hall, II, 76, 78 L. cuneala, n'hitfuld. I, 61 M. Maria, Hall, . . II, 67 L. Ella, Hall and Whitlield, . I. 61 M. Mceki, Hall, . . II, 78 L. Maera, Hall and IVA/yieM, . Ii 61 M. meta, Hall, n. 78 L. minima, Whitfield, 1, 62 M nasuta, Hall, . . 11, 78 L? minuta, i/o/; and WViii/fcirf, . I, 61 M. oblata, Hall, . . II, 76 L. Morsii, A', if. Winrhell, I, 62 M. princeps. Hall, . II, 78 Li. pcrattenuata, Whitjield, I> 61 M. rostrata. Hall, . II, 78 L. pinniformis, Oicfn, I, 60, 61 M. subquadrata. Hall, . II, 78 Lingulops Uranti, .sp. nov., . I, 19, 20, 21, 23, 32, 50, 173 M. AValcotti, sp. nov., . . 11, 75, 76, 365 L. Xor^voodi, James, . I, '^0, 21, 23, 32, 50, 173 Mtristma didyma, Dalman, . II, 60 L. Whitliuldi, Hall, I, 18, 19, 20, 21, 23, 26, 32, 50, 173 JI. Maria, Hall, . . II, 60, 68, 69 Linnarssonia pretiosa, Billings, I, 109 M. rectirostra. Hall, . n, 08 L. miscra, Billings, . . . I, 1 07, :o8. 109 M. tumida, Dalman, . II, 68 L. sagittalis, Salur. I, 103, 109 Metaplasia py.xidata, Hall, . . II, 67 L. taconica, Wakott, . . i, io6, 1 07, lOS, 109 Mickwitzia monilifera, Linnarsson, I, 86 L. transversa, llartt, . . . I, 1 07, 108, 109 Mimulus contrarius, Barrande, I, 273 Liorhynchus Boonensis, Shumard, H, 191 M. Waldroncnsis, Miller and D i/er, . 1, 27J, 274 L. globulit'ormis, Vamtxem, II, 191 Monomerella Egani, sp. nov.. . 1,42, 17S li. Greenianus, Ulrich, . IIj 194 M. ' Groenii, sp. nov.. I, 42, 45, 52, 174, 175 L. Kelloggi, Hall, Il> 194 M. Kingi, sp. nov , ■ I, 12, 174 Tj. Laux-a, Billings, II, 194 M. Liudstroemi, Davidson and King, . . I, 41 Ij. Lesleyi, sji. nov.. II, 368 M. orbicularis, Billings, I, 41 L. limitaris, Vanuxevi, II> 194 M. Ortoui, sp. nov., . I, 42, 43, 175 L. nies.acostalis, Hall, . II. 194 M. ovata, Wliiteaves, . I. 42, 54 L. multicostus. Hall, . II, 194 M. ■\Valmstedti, Davidson and i K'lg, . . I, 41 L. Newberryi, H«Kand H^/ii!/;eW, • II, 194 Neobolus Warthi, Waagen, . I, 84 L. quadricostatus, Vanttxem, . II, 194 N. AV3Tinii, Waagen, I, 84 L. sinuatus. Hall, n. 194 Newberria Cla.v])olii, Hall, . II, 263, 264 Lyttonia nobilis, Waagen, II, 313 N. Missouriensis, Hall, . 11, 263 Macandrevia cv.anium. . II, 305 Ncetlingia Tscbeffkini, de Verneued, II, 228, 229 Jlagcllania llavescens, Lamarck, II, 326, 831 Notothyris? Smithi, Derby, . II, 267, 275 INDEX. 385 P IQB. PACK. Notothyi-is subvescicularis, Davidson, . n. 274 Orbiculoidea Forbesi, Davidson, . I, 116, 125, 126, 129, 135, 160 Nucleospii-a Ban-isi, WUiie :\wl Whitfield . II, 145 0. grandis, Vauuxem, .... I, 133 N. concenlrica. Halt, u, 145 0. llerzeri, sp. nov., I, 178 N. concinna, i/a^;. II, 145 0. Morrisi, Davidson^ . I, 133, 160 X. clegans, Hall, . II, 145 0. Newberry i. Hall, I. 130 N. pisiformis. Hall, . 11, 145 0. nitida, I'iiillips, I, 136 N. pisum, Sowerbiy, • u, 145 O. nunuilus, sp. nov.. I, 178 N rotunda, Whitfield, n, 145 0. llandalli. Hall, I. 133 N. ventricosa, Hall, II, 145 0. tenuilamellata. Hall, ■ 1, 127, 135 N.' sp. ? . II, 146 0. (Uicmerella) grandis, Vanuiem, I, 178 Numulns Brattensbttrgetisis, Stoboeus, I, 150 0. (Scliizotreta) oralis, sp. nov.. I. 170 Oliolella atlaiitica, Walcoti, I, 69 Oris kania navicclla, sp. nov.. II, 269, 270 0. ? arnbi^ua, Walcott, . I, 09, 78 Orthambonites transversa. Pander, I, 237 0. Ceiti, Davidson, I, 03 Ortliis acutiloba,Iling\ichcre, I. 205 0. calata. Hall, I, 69 0. acutilirata, Conrad, I. 223 0. chromatica, Billings, . I, 87, 6S, 69 70, 72, 73, 75, 76 0. aHjuivalvis, Hall, I, 191, 221 78, 91 O. alternata, Souxrby, I. 203 0. cingulata, Billings, . 1,69, 91 0. siUn. Hall, I, 225 0. Circe, Billings, . . I,6S, 69 0.? apicalis, Bdlings, I, 217, 240 0. crassa, Hall, . . I, 67, fiS, 6!) 70, 71, 72, 75, 78 0. araclinoidea, Phillips I, 256 O. desiderata, Billings, I, 57, 09, 75 0. arcnaria, sp. nov.. I, 224 0. desquamata. Hall, I. OS 0. Arnianda, Billings, I, 217; 11, 214 0. ? disnoiilea. Hall ami Whitfield I, 69 0. assimilis. Hall, . I, 2J4 0. gemma, Billings, I, (!S, 69, 70, 71 0. Aurelia, Billings, I. 221 o. y Ida, Billings, 1, 69 o. A'jmara, Salter, II. 137 0. maoulata, Hicks, . I, 6S, 109 0. Barabiiensis, A. Winchell, 11, 212 0. misera^ Billings, I, 69 0. basalis. Dalnian, I. 191,192, 207 0. nana, Meek and Hayden, . I, 60, 70 0. Battis, Billings, I. 222 0. nitida. Ford, •. 1,60, 70 0. Baylii, Uouault, I, 213 0 Phillipsi, Hall, I, 91 o. bellai'ugosa. Hall, I. 222 0. polita. Hall, I,(i8 69, 70, 72, 73, 83 o. bellula, James, . I. 224 0. pretiosa, Billings, I, 70 0. Ijiforata, von Schlotheim, I, 190, 200, 223 0. Sabrina;, Callaway., . I. 68, 103 o. Billingsi, Hartt, I. 232 0. sagiltalis, Salter, I, 68, 107, 108 0. Billingsi, SalTord, I, 219 o. transversa., Hartt, ■ 1,70, 107 o. biloba, Linne, . . .1, 90, ao4, Ida, 223 Obolu. advena^ Barrande, . 1,68, 69 0. bisulcata, Emmons, . II. 146 o. antiquissimus, von Eicliwald, I. 82 0. borealis, Bdlings, . I, 222 o. ApoUinis, von Eichwald, I, 51, 89, 82, 339 0. Bouchardi, Davidson, . I. 217 0. Appolinusj Owen, I, 72 0. Burlingtoneusis, Hfdl, I. 225 0. ? Bohemicus, Barrande, . I. 101 o. callactis, Dalman, I, 191, 192, 195, 196, 228; U, 133 0 ? computus, Barrande, . . 1,68, 73 333, 340 0. ingrieus, von Eichwald, I. 82 0. calligramma, Dalmaii, 1,190,191,192,193,194, 195 o. l.abradoricus, Billings, . I, 94 ; U, 321 219, 231, 238, 242, 244 o. pidclier, Matthew, • 1.81, 183 0. calligramma, var. Davidsoni, de Verneuil, 1, 193, 227 0. Quenstedti, Mickwitz, I> 839 0. calligramma, var. fiabellites, Foerstc, . I, 228 0. siluricus, von Eichwald, 1. 82 0. calligramma, var. orthambonites, Billings, . I, 221 (Ehlc ■tella pleurites, Meek, • 1, 1-H, 169 0. carinata. Hall, I, 21.3, 220 oiaiK mina decii)iens, de Koninck, u, 314 0. circularis, Roemer, I, 259 Orbicula antifriiissima, von Eichwalil, I, 118, 119, 140 0. circulus, Hcdl, . I, 210, 224 0. Buclii, de Verneuil, . I, 151, 152 0. Clarkensi.s, Swallow, I, 225 0. calata. Hall, I, 69 0. Cleobis, Hall, . I, 225 0. crassa. Hall, I, 72 0. Clytie, Hall, . . I, 202, 203, 223 0. deformata. Hall, . I, 150 0. concinna. Hall, I, 207, 2-24 0. Morrisi, Davidson, I 128, 129, 130, 160 0. corallina, Waagen, I, 210 O. norvegica, Sowerby, 1, 121 0. Corinna, Billings, I, 217 0. uorvegica, Lamarck, . I. 122 0. costal is. Halt, . . I, 221, 227, 228; H, 310 o. punctcua, Sowerby, I, 140 0. crassa, Meek, I, 223 0. reversa, de Terneuil, . 1, 118 0. cTcntstria, Philips, I, 24S 0. ? sqnam if or mis., Hall, I. 159 0. crisnata, Emmons, I, 22* 0. terminalis, Emmons, . I. 140 0. Cumberlandia, Hall, I, 225 Orbic uloidea, sp. ? Meek, I, 127 0. cuneata, Owen, . I, 225 0. cornea^ Dwigbt, . I,HG 124, 126, 129, 135 0 eve las. Hall, I. 223 0. Davidsoni, d'Orbigny, . I, 160 0. cylindrica, SIcCov, I, 262 386 INDEX. PAGE. Orthis Dal.v;inii, Miller, I, 225 Orthis 0. Davidsoni, t'e Fcrneui;, I, 192, 221, 228 0. 0. Daytonensis, Foerste, . I, 222 0. 0. det.ecta^ Conrad, I, 222; II, 333, 337 0. 0. deformis^ Hall, . 1, 255 0. 0. demissa, Dalman, I, 191, 192 O. o. Derbyi, Waagen, I. 214 0. o. Desliayesi, I, 243 0. o. dicliotoma, Hallf I. 221 0. 0. discus, Hall, I, 210, 225 0. 0. dispai'ilis, Conrad^ I, 191,221, 228 0. 0. dubia, Hall, ■ I, 210, 225 O. 0. electra, Billings, I. 223 0. 0. clcjjaiis, Bouchard, I, 219 0. 0. elcsraiitula, Dalman, I, 191, 11)2, -207, 224, 341 0. 0. elcgantiila, var. i)arva Foerste, 1> 224 0. o. Ella, HM, . I. 221 0. 0. omacerata, Hall, I, 207, 224 0. o. emincus. Hall, . I, 210, 225 O. V 0. ? erratica, llall, 11, 157, 158 0. 0. Eurekensis, Walcott, . I. 232 0. o. EuryODC, Billings, T, 221, 228 0. o. Evadnc, Bdlings, I, 223 O. 0. exoavata, Geinitz, I. 315 0. 0. eximia, de Venieuil, I> 260 0. 0. expansa, Sowerby, I. 283 0. 0. extcnsa, Pamler, I. 219 (). 0. fasciata. Hall, . 1, 200, 222 0. 0. Tau^ta, Foerste, , I, 222 0. 0. fissicosta, Hall, I, 194, 221 0. o. flabcUUes, Hall, I, 227, 223 0. o. fabdUdum, Hall, I, 221, 227 0. 0. flabellulum, Sowerby, . I, 227 0. 0. gemmicula, Billings, I, 217, 244 0. 0. gibbosa, Billings, I, 224 0. 0. glypta, sp. nov., II, 359 0. 0. Halli, Safford, . I, 200, 223 o. 0. heinipronilcs, von Buch I, 238 0. 0. hipparionyx, Schnur, I, 258 0. 0. Hippolyte, Billings, I, 217, 221, 22S 0. 0.? Holstoni, Safford, I, 218, 340 o. o. hybi-ida, Sou-erby, I, 210, 224, 342 0. 0. idonca. Hall, . I, 225 0. 0. imperator, Billings, I, 222 0. 0. impressa. Hall, . I, 21-2, 214, 226 0. 0 incisiva, Waag^n, I. 210 0. 0. infera, Calvin, . I, 224 0. 0. insculpta. Hall, I. 222 o. 0. insignls. Hall, . I. 211 o. 0. ijisidaris, Eichwald, I, 270 0. 0. lowensis. Hall, , I, 212, 226 o. 0. Iphigenia, Billings, I, 222 0. 0. Jamc&i, Hall, . I, 194, 195, 221 o. 0. Kankakensis, McChesney, I, 221 o. 0. Kaskashiensis, JlcChesney, I, 350 0. 0. Keoknk, Hall, . I. 262 0. 0. laticosta. Meek, . I, 223 0. 0. LaurenHna, Bdlings, . . I, IM , 231, 23S ; II, 337 o. 0. lens, Phillips, . II, 101 0. 0. lenticularis, Wahlenberg, .1, 207, 224 0. 0. lentiformis, Hall, I, 224 0. 0. Xeonensis, Hall, I, 224 0. 0. lepida, Hall, . I, 207, 221 0. 3 Lcucosia, Hallt . lepida^ Schnur, . Linneyi^ Nettelrolh, Livia, BiUinqs^ . Lonent^is, Walcott, loricuhi, sj). nov., Lucia, Billings, . lynx, von Eichwald, MacfarUinii, Meek, Macleodi, Wkitjield, Maria, Billings, in a rm o re a , Waagen Mceki, Miller, . Merope, liillings, Michclini, Leveille, niiuiica, Barrande, Minneapolis, N. H. Missouriensis, Swallow ^Morganiana, Derby. niultisecta, Meek, multi^triata, Hall, musculosa, Hall, Mycalc, Billings, Nevadensis, Meek, Nisis, Hall, oblata, Hall, occasus, Hall, . occidcntalis, Hall^ Olivierianaf de Vemeuil Orbignyi, Davidson, ortltambonites, Billings, Oweni, sp. nov., pahnata, Salter, Panderiana, si>. nov., J*ecosi, Marcou, . pecten, Dalman, . pectinella, Emmons, pectinella, Emmons^ \ pcduncularis, Hall^ Peloris, Hall, , Penelope, Hall, Penniana, Derby, Pennsylvanica, Simp. Pep^na, Hall, perelegans, Hallj perveta, Conrad, planoconvexa, Hall, platys, Bdlings, plicatella. Hcdl, porcata, McCoy, prava, llall, productoides, Murchiaon propinqua, Hall, punctata, Hall^ punctostrjata, . Qiiacoeusis^ Matthew quadrans, Hall, quadricostata, Vanu:rem. recta, Conrad^ resupinata, MartiJi, rosupiuoidcs, Cox^ retrorsa, Salter^ retrorsistria, McCoy I, r.i7 1,190 I, 225 . I, 259, 260 U, 181 I, 225 I, 222 222 ; II, 333, 337 I. 225 II, 202, 223 1, 180, 212, 22B I. 224 I, 222 I, 214 I, 20S, 207, 224 I, 242 194, 219, 225, 343 I, 200 I, 224 I. 225 213, 214, 216, 226 • I, 207, 22t • I, 212, 226 210, 211, 225, 258 • I. 217, 232 I, 226 I, 217 I, 210, 224, 225 I, 225 . I, 202, 222 I, 266 I. 283 • I, 221, 228 I. 225 II, 138 Expl. Plate I I, 210, 225, 226 I, 191 195, 196, 232, 228 ,Hall, 1,222, 228 I. 226 . I, 225, 343 . I, 211, 225 ■ I, 210, 226 I, 225 . I, 230, 232 . I, 207, 224 ■ I, 207, 224 . I, 207, 224 . I, 218 1, 194, 196, 221 . 1, 197, 222 I> 225 I, 317 I, 212, 226 I, 217 I, 217 I. 232 I, 224 11, 193 I, 222 199, 211, 213, 226 I, 213, 226 I, 197, 222 I, 203 INDEX. 387 Orthis rcvcrsa, Salter, , , O. robustay Hall, O. rugiplicaia, Hall, O- Saffordi, sp. iiov,, O. ScoTiUii, Miller, O. sectostriata, O. Seraele, Hall, . O. senecta, sp now, O. siuuata, Hall, . O. socialis, Barrande, O. solitaria Hall, . O. spirij'eroides, McCoy, O. Stoncnsis, SaJ^hr/i, O, striatella, Dalman, O. striatula, Schlotheim, . O. strophoinenokU's, Halt, O. subajquata, Conrad, O. subcarinata. Hall, O. subelliptica, niiiie and Wkiijiel,!, O. suborbicularis, Hall, . O. subquadrata, Hall, . . I O. supcrstes, sp. nov., O. Swallovi, Hall, O. Sweeneyi. JV. H. Winckdl, O. testudinaria, Dalman, I, 19U, liil O. tetragona, O. Thiemii, White, O. Tioga, Hall, O. ti'iccnaria, Conratt, O. triplicalella, Meek, O. Tritonia, Bilhngs, O. tubulostriata. Hall, O. Tulliensis, Hall, O. ubcris, Billings, O. um'jonata, Conrad, O, utiibraculum,Sc\\\o{\\Q\n\, O. Vanuxemi, HalU O. Vanuxemi, var. pulchclla, Uerrick, O. varica, Conratt, . O, Wan^enheimi, de "N'erneuil, O. Wisbyensis, Limtstrain, O. Whitfieldi, iV. H. WimMl, . O. zonata, Dainian, O. (Dalmanellnl air.uaria, i?p nov., O. (Dalmauella) supcrstes, sp. nov., O. (rhusiomys) loricula, sp. nov., O. (RliipiilomcUa) Oweni, sp. nov., O. (Scbizophoria) senecta, sp. nov., Orthisinaadscendens, Pander, . O. anom.al.a, d'Orbi^ni/, O, cava, Ban-ande, O. crassa, 3Ieck and Ilaydcn, O, festinata, Elllinjrs, O. gri"anda?va, Billings, O. Missouriejms, Swallow, O, occidentalis, Xcwberry, O. orientalis, Wllitficld, . O. transversa, AValcott, O. Verneuili, Elclnval I, Ortborbynchula Lmneyi, Xetfelroili, OrUiostiopbia strophomenoides. Hall, Orchothetes desideratus, sp. nov., . PAGE. I, 197 I, 262 I, 217 I, 218, 340 I, 222 I, 221 I, 223 I. I, 198, I, I, 22G 213 200 225 I, 271 1, I, I, 191, I, . 1, 199, 194, 207, I, 207, I, I, 191, 19U, 197, I, 217, I, 213, I, 19(i, 222, 192, 203, 206, 217, 218, I, I, I, 212, I, 191, 193. I, 194, I, 217, I, 210, I, 212, I. II, I, 248, I, 225, I. 204, 203, I, I, I. 224 303 213 223 224 224 225 223 3)1 224 22ti 228 207 224 219 225 226 2.'1 221 232 223 226 224 55 23C 312 225 223 319 207 221 I, 191 I, 341 I, 34^ I, 341 1,343 I, 343 , 191, 237 237 271 I, I, I. I, I, I. . I, 231, 11. 182, I. I, 262 230 231 2S6 266 230 230 237 337 200 I. 345 Orthothetes pccten, Dalman, . O. radiata, Fischer, O. socialis, Fisclier, O. subplanus. Conrad, O. uuxhviiQviXnm, von Buck, Parastrophia Grcenii, sp. nov., P. (liverffcns, sp. nov,, . P. latiplicata, sp. nov., . P. multiplicala, sp. nov., Parazyga Deweyi, Hall, P. hii-suta, Hall, . Patella anomala, Miiller, . P. antiqua, Schlotlieira, . P. implicata, Sowerby, Paterina .Swantoucnsis, Walcott Patcrula Bobemica, Barrande, Pentagonia Peersi, Cozzens, P. unisulcata, Conrad, P. unisulcata, var. biplicutn. Halt, P. unisulcata, var. uniplicata, Hall, Pentamerella ai-ala, Conrad, , PACE. dubia, Hall, niicula, Hall, obsolesceus. Hall, papilionensis. Hall, Pavilionensis, Hall, Pentarnerus Areyi, sp. nov.. P. Aylesfordi, Sowerby, . P. Barramlii, BiUiug-S, P. Bastdciricus, de Verncuil, P. bl.-uiuatiis. McChesney, P. borcalis, Eichwaltl, P. Ctilletti, iliUer, . P. complanatus, Xettclroth, P. crassicosta, Ilall and "Whitficdi P. cylindricus, Hall, P, decHssatus, Whitcavcs, P. elongatus, Vanuxcni. P. Esthonus, Eictiwald, . P. fornimtus. Hall, . P. galeatus, Dalman, . . II, P. Knappi, Hall and Whitfleld, P. Knighti, Sowerby, P. lajvis, Sowerbij, . P laqueatus, Conrad, , P. lens, Sowerby, . P. lin^uifer, Sowerby, . . n, P. Littoni, Hall, . ■ . P. nofjilis, Emmons, P. nucleus. Hall, P. Xijsius, Hall and WhitQcId, P oblongus, Sou-erl/i/, I, P. oblongus, var. .Maquokcta, P. ohlongus, var. snorectus, var. P. occidentalis, Hall, P. pergibbosus, Hall and Whitfield, P. pseudobasnictrteus, Tscliemyschew, P. pseudogaleatus, Hall, P. reversus, Billings, P. Itoemeri, sp. nov., P. rotundatus, Sowerby, . . . .11, P Samojefllcus, Keyserting, . . .11, I' Sidxri, von Bucli, . . . U, 246, 350 256 I. I, I, 256 I, 256 . I, 2.39, 345 II, 222, 3C7 II, 222, 3(50 222, 2J3, 308 222, 223, 307 1-28,129, 114 111, 128, I. 122, I. I, II, I. II. H. II. U, H. 212. II, 212, II, H, 129 150 158 158 321 79 ao 81 81 81 2(3 213 213 213 H, 245 11, 245 II, 213 230 244 235 2'12, 213 42 II II II U, 23J, 239 II, 234, 210 II. II. II. II. 237, II, II, II 212, 213, 212,243, U. II. II, II. II. 144. II. 235 235 235 ■238 233 252 210 214 217 2.">S 236 237 234 251 245 231 288; U, 231, ar. nov., uov , II, . II. II, 234 . II. 247 II. -235 237, 233, 218 II, 239 238, 239, 239,210, n, 239, II. II, II. 240 248 210 235 212 217 2-23 210 247 388 INDEX. Pentamerus tenuico.^ta, Hall, P, tenuistriatits, Walmstedt, F, nniplicatuSf Xcttelroth, P. ventricosus, Hall, P. Verneuili^ Hall, , Pexidella Strohmayeri. Suess^ Pholidops antiqua, Srhlotheimi P. arenaria, HaH^ . P. bellula, WaXcott^ P. calceola, sp. nov,, P. Ciuciunatieusis, Ha//, P. llamiltoni.'c, Hall^ P. implicata, Sowerbi/, P. Icpis, sp, nov., . P. lin^uloldes, Halt^ P. oblata, JIall, P. ovalis, nail, P. ovata Baltf P. patina, sp. nov., P. sp. ? . . . P. squaraiformis, Holly . P. terminalis, Ballf P. Trentonensis, Hall., I'lectambonites crassa, Pander^ P. oblo/iga. Pander, P. ovata^ Pander, . P. plauissima, Pander, P. producta, sp. uov., P. tcstudinata, Pander, P. traiisversalis, Wahlenbcrg^ Plicatula striatocostatai Cox, Polytcechia apicalis, Whit/ielti, Porambonites intermedia. Pander, P. obscurus, Hall and Whitfield, P. Otlawaensis, Billings, . Producta analoga. Phillips, P. modesta^ i^^y) Hall, P. monilifera, JlcCoy, P. rugosa, Hisinger, P. truncata, Hal!, . P. (TripUcia) VKmilifera, M<"Coy . Prodiictella hystricula, Hall, Productus ajquicostatus, Hall, P. requiradiatus, Shunuird, P. alternatus, Norwood and Prattcn, P. ^Vltonensis, Norwood and Pmttfn, P. Aniericanus, Swallow, P. arcuatus, Hall, . P. asper, McChesney., P. biseriatus, Hall, P. Burlingtonensis, Hall, P. Chesterensis, Wortkefi, P. Christian!, de Koninrk,. P. cla^'^IS, Norwood and Prattcn, P. comoides, Sowerbj-, P. complectens, Etheridge, P. compressus, Waagen., . P. Cora, d^Orbigiiy, P. costatus, Sowerby, P. dissimilis, Hall, . P. ermineus, de KonincJc, . P. Geinitzianud, dc Eoninck, P. genuinus, Kutorgay PAGE. PAQB. II, 2.'!5 Productus Hallianus, W.llcott, . I, 332 It, 231 P. horridus, Soxcerby, I, 327 II, 247 P. L;i.s:incnsis, Worthcn, . I, 327, 332 II, 213, 243, 2U P. lameUosiisy S.ainUierjrin-, II, 130 II, 224 P. latirostratus^ Ilowse, . I, 320 11, 102 P. LeonfiartJi^ Wissmann, . I, 326 I, 157, 159 P. LlansoUemis^ Dlivitlsou, I, ,■517, 318 n. 325 P. longispinus, Sowerhy, . 1, 316, 332 I, 157 P. ■ magnus, il/«t and IVbrr^if/j, . I, 327 I, 157, isa P. marginiciuctus, Prout, I, 327 I, 157, 159 P. Martini, Sowerby, I, 325 , 157, 15!); 11, 325 P. mesolobus, Phillips, . I, 327 I, 157, 159 P. mytiloidcs, Wangen^ I, 326 I, 157 P. Nebrasceusis, Owen, . I, 263, 325, 827 I, 157; II, 325 P. NcH'bciTvi, Hall, I, 339 I, 157 P, nodosus, NewbeTTij, I, 326 I, 157 P, Kystianus, de Koninck, I, 334 I, 15V, 159 P. opuntia, Waagen, I, 327 I, I8« P. ovatus, Hall, I, 326 I. 159 P. pileiformis, Newberry, . I, 826 I, 156, 159 P. Prattenianus, Norwood, I, 326 I, 157 P. proboscideus, de Veineuil, . I, 326, 333, 334 I, 15V. 159 P. puiictatus, Martin, I, 327 I. 297, 298 P. Rogersi, Norwood ancl Pratten, I, 327 I, 300 P. scabriculus, Martin, I, 327 I, 300 p. semiroticubitus, Martin. I, 325, 327, 329 I, 296, 297, 298 P. splendens, Norwood and Pratten, I, 832 11, 360 P. striatus. Fischer, I, 326, 334 I, 297 P. siibandeatus, Murcbison, I, 317, 328 I, 29S, 299 P. sulcatus, Castelnait, I, 260 I, 265 P. S}Tnmetricus, McCliesiuy, I, 327 I. 239 P. tcnuicostatus. Hall, I, 827 II, 226 P. umbonillatm, Davidson, I, 320 II, 228 P vittatus. Hall, . I, 827 11, 228 P. Wortbcui, ifail. I, 827 I. 280 P. (Daviesiella) Llangollcnsis, Davidson, . I, 317 II, 155, 157 P. (Etberidgina) complectens, Eiluridge, . I, 335 I. 270 P. (Proboscidella) proboscideus, de Verneuil, I, 333 I, 279 Pronites ctdscendens. Pander, I. 234, 235, 237 I, 316 P. humilis. Pander, I, 238 I, 271 P. oblonga. Pander, I, 238 I, 31G P. (Clitambonites) adscendens, Pander I, 2,18 I. 326 Protorliyncha dubia. Hall, II, 181 I, 326 Protozyga exigua, i/a;(. 11, 119 ten, I, 327 Ptychospira ferita, von Bach, . II, 113 ttn, . I. 327 Rafinesquina alternata, Conrad, I, 260, 286 I, 326 R. expansa, Sowerby, I, 250 I, 327 R. Jukesi, David-son, II, 339 I, 327 Renssela;ria ajquiradiata, Conrwl, 11, 258 I, 327 R. Cayaga, sp. nov.. . II, 258 I. 327 H, Condoni, McChesney, . 11, 280 I, 327 R. Cumberlandi:K, Hall, . II, 258 I, 327 R. eUiptica, Hall, .... II, 268 I. 331 R. ? Johannis, Hall, .... II, 2G2, 263 I, 317, 318 R. IfBvis, Hall, .... II, 257, 264 T, 316, 335 R. lavis. Meek, .... U, 264 I, 326 R. Marylandica, Hall, II, 258 I, 326 R. mutabili.s. Hall, . . II, 258, 259, 266, 297 I, 327 E. oroides, Eaton, . . 11, 245 258, 259, 262, 349 I, 333 R. Portlandica, Hillings, . II, 273 I, 334 R. .Suessana, Hall, .... II. 269, 260, 266 I, 327 Retzia Adrieni, de Verneuil, . II, 106 107,108,110, 121 I. 334 R, apriniformis, Hall, II, 111 INDEX. 389 Retzia carhonaria^ Davidson, R. ro/nprrfisa, Meek, R, Davidsoni, de Koliiuck, R. Eugenia, BiliingS, R, granuli/era, Heck, R. intermedia, de Konilu'k, R. lepida, Kayscr, . R. longirostrisy Kayscr, R. Meekana^ Shumard, R. Osagensis^ Swallow, R. papillata., Shumard, R. punctnli/era, Shumard, R. radialiSf Phillips, R. serpentina^ de Koninck, R, sexplicata, White and Whitlield, R. soltrina^ Beecher and Clarke, R. ulotltrir^ de Koninck, . R. vera, Hall, R. Woosteri, White, Rhinobolus David:?oni, sp. nov , K. Galtensis, Billings, Rhynchonclla ,^brullta, Hall, . R. acinus, Hall, R, acuminata, Martin, R. erquiradiaia. Hall, R. aha, Calvin, R. altilis. Hall, R. angulata, Geinitz, R. anisodonta, Phillips, . R. Barrandii, Hall, R. ? Bitlingsi, Hall, . R. capax, Conrad . R. carica. Hall. R, Carolina, Hall, . R. castanea. Meek, . R. congregata, l,(}nva.df R. contracta. Hall, . R. cuboi'/es, Sowerby, R. dentala. Hall, R. Dotis, Hall, R. duplicata. Hall, . R. Eatonii/ormis, McChesney R. Emmonsi, Hall and WliitlieM R, eximia, Hall, R. explanata, McChesney, R. fornwsa, Hall, R. fringilla, Billings, fi. glacialis, Billings, R. glans-fagea, Hall, R. Crrosvenori, Hall, R. Hors/ordi, Hall, R. increbescens, Hall, R. Imiianensis, Hall, R, intermedia, Barris, R. loxia, Fischer, . R. Marsha^lensis, A. Winchell R. Mcrjemiorji, do Verneuil, R. mica, Billings, . R. Missouriensis, Shumard, R. mutetbilis. Hall, . R. mutata. Hall, R. nt'glecta. Hall, R. nucleolata, HaU, . PACE. II, 122 H, Ui II, li-2 II, 111 II, 126 11, 122 II, 131 II, 112 II, 122 II, 120 II, 122 II, 120 II, II, 113, 122 119 II, 112 II, 112 II, 122 II, 117, 118 n, 122 . I, 4.1, 176 . 1,15, 176 II, 19!) II, 190 11,179,203, 201 II, 190 II, 203, 201 II, 190 I, 217 II, 204 II, 191, 19S II, 192 II, 183, 185 . II, 192 II, 192 II, 194 II, 190, 192 II, 192 11,200,201, 203 II, 185 II, 192 II, 192 II, 201 n, 200, 201 II, 192 II, 201 II, 187, 1S8, 189 U, 190 II, 190 II, 268, 268 II, 201 II, 192 II, 183, 185 II, 190 II, 200 177, 178, 179, 203 II, 192 H, 204 II, 157 II, 204 II, 199 II, 204 II, 190 II, 199 Rhynchonelta obtusiplieata, Hall, R. orbieiUaris, Hall, R. Ottunum, While, R. parallelepipeda, Ki-onii, . R, plena, HaU, R. pliopleura, Conrad, R. primipilaris, von Ituch, R. procu/joides, Kayser, R. prolijiea, Hall, . li. psittacca, Gmelin, R. piignus, Martin, R. pustulosa, Whili;, R. reniformis, Sowerby, . R. Saffardi, Uall, . R. Sageriana, A. M'iachell, R. Sappho, Hall. R. scotiea, i)avidson, R. speciosa. Hall, . R. Stevensi, Hall, . A'. striatocostata, Meek and Wortlien, A'. Slricklandi, Schaur, A'. Stricklandi, Sowerby, . R, sttbcuncata. Hall, R. snb-Wilsoni, d'Orbigny, R. Tethys, Killings, R. triangularis, Sowerby, . R. Uta, Marcou, . R veliicala, UivU, . R. ventricosa. Hall, R. veniistula, Ilall, R. Whitii, HaU, . R. Wilsoni, von Buch, . .II, Ilhynchopora Xikitini, Tschemyschew U. Youugi, Davidson, Khynchospiraevax, Hall, 11. fonnosa, Hitll, . R, lepida. Hall, R. 7ujbilis, Hall, U. scansa, sp. nov., Uliynchotrcta cuucata, Dolman, K. cuneata, var. Americana, Hall, Kichthol'enia Lawrenciaua, de Koninck, R. Sinensis, Kayser, RoemercIIa graiiilis, Vcrnu-xtm, Komiugerina Julia, A. Wtnebell, Scaphiocuilia Bolivicnsis, Whitfield, Scenidium areola. Quenstedt, . S. Baylii, RouauU, . S. devonicum, ir«/co((, S. GrayLTi, Davidson, S. Halli, Safford, . S. insignc. Hall, S. . Lewisi, Davidson, S. Lewisi, var. Ilughesi, Davidson, S. Lewisi, var. Woodlandenso S. MojUeri, Tsekcrnyschew, S. pyramidalc. Hall, S, Shallockense, Davidson, S, uralicuin, Tschernyschew, Schizambon ? Canadensis, Ami, S. ? lissus, Kutorga, . S. typicalis, IlWroff, . 1,111,11 Schizocrania lUosa, Hail, Davidson, 190. PASS. n, 190 II, 192 II, 2tioa, Kutorga^ Selenella gracilis, sp. nov., Seminula ambigua, Sowerbt/, . S. Dawsoni, sp. nov., S. petttahedra, PliilHps, S. Rogersi, sp. nov., S subtilita, Hall, Sieberella galoatus, Dalman, . S. Sieberi, von Buck, Siphonotreta aculeata, Kutorga, S. anglica, MurriA-, S, conoidcs, Kutorga, S. Jissa, Kutorga, , S. fornicata, Kutorga, S, micuhi, McCoy, . S. Jlinnesotcnsis, sp. nov., S. scotica, Davi(lso7i^ S. scotica, var. Canadensis, Ami, S. tentorium, Kutorga, S. unguiculata, Eichivald, S. verrucosa, de Verneuil, . Spirifor acuminatus, Cunrwl, . S. acuticostatus, de Kuniiick, S. aquirostris, Scblotboim, S. albapinensis, Hall and Wkitjieldy S. alius, Hall, iS. Ambiensi-s, Waagen^ S. ambigiius, Sowerby, S. angustus, Hall, . S. annectans, Walcott, S. Anossofi, d£ Verneuil, S. aperturatus, Scklotlieim^ S. arctisegmentus, Hall, . S. areuosus, Conrad, S. arrectus, Hall, . S. asper, Hall, S. asperatus, Rin^ue/jerg, . S. audaculus, Conrad, S. Belphcgor, Clarke, S. bicostatus, Vanuxem, . S. bicostatus, vav. petilus, Hall, S. bidorsalis, --1. Winchell, S. bifurcatus, Hall, S. liillingsanu-s, Miller, . S. bimesialis. Hall, S. bipUcatus, HaZ/, S. BjTnesi, Nettelroth, S. Canandaiguie, sj). nov., S. cameratus, ^lortnn^ S. centronatus, A. Wincliell, S. cheiroptyx, do Verneuil, S. clarus. Swallow, S. concinnus, J/rt/^, S. consobrinus, d'Orbigny, S. corculum, Kutorga, S, crenistria, Piiillips, S. cnspatus, sp. nov , S. crispus, Hissinger, PAGE. PASE. . I, 13:!, U4 179 Sp rlfer crispus, var. simplex. Hall,. .11, 19, 36 . I, 143, 144 179 S. ciUtTijugntus, liocmer. 11, 31 I, 95 s. Cumburlainiiic, Hail, . . 11, 17, 36 . I, -ill. 343 s. cui-vatus, Hrhlatlieim, . .11, 10, 33 I, 136, 140 ,s. cuspidati/orinis^ Miller, II, SO I, 128, IGO s. ctispitlutus, Martin, , ■ 11,8, 11 . II, 270, 271 370 s- cycloi)tei-us. Hall, II, se II, 93 .s. Davisi, Nettelrotli, II, 36 . II, juuctu3, Soiverby, 11,21 , 24, 27, 37, 49 II, !I5, lliu s. clisjuiielus, var. sulcMl'er, var. iiov., . 11, 21, 37, 361 11, 24G, 247 s. ilisparilU, Hall, II, 36 II, 24G .s. ilivario.atus. Hall, 11,21,27, 39 I, 113 s. iluoJeiiarius, Hall, II, 19, 37 I, 113 .s. tIui)licosta, Phillips, II, 10 I, 113 s. En^tlmaiini, Meek ailii W orthen • II, 36 111, 114, 115, 116 s. Eudora, Hall, . II, 13, 36 I, 113 s. euryglossus, Schniir, II, 33 I, 113 s. eurytiiies, Oioen, 11,29,31, 39 I, 112, 177 s. eurylines, var. loruaculu ■,, Hall, ■ n. 39 I, 113, 115 s. erteniiditis, Hall, • II. 61 I, 115 .s. /oitigaius, Meek ami Woi Ihcn, II, 26 1. lU'J, 111 s. limbriatus, Conrwl, 11,17 , 20, 21, 33, 37 1, 111, 112, 113 •S. Foggi, Nettelroth, . II, 35 I, 113 s. Forbesi, Hall, II, 26, 38 II, 31, 39 s. furmosus. Hill, . • 11. 39 II, 39 s. fovnax, Hall, . II, 31, 39 II, 227 s. fusilbrmis, Phillips, II, 9 • II, 38 s. ^]iLhey, Martin, . 11,11 32, 33, 34, 40 11, 30, 42 s. glabcr, var. conlraclus. Meek and Wurthen, II, 33, 40 II, 26 s. glaber, var. Xevadensis, Walcott • II, 33 ■ II, 93 s. granuliferits. Hall, II, 29 II, 31, 39 s. granulosus, Conrati, 11 29, 30, 31, 39 II, 39 s. gregarius, Capp, II, 17, 36 II, 25 s. Grieri, Hall, II, 24, 27, 38 II, 12, 21 tj. Griniesi, Hall, . II, 23, 25, 38 II, 36 s. liemii-.yclus. Meek anil Worthen, II, 37 II, 24, 27, 37 s. hemiplicatus, Phillips, . I, 215 . 11, 17, I'J, 37 .s. llirtus, White and Whitjielii , • II, 21, 37 II, 29, 31, 32, 39 s. Iloliljst, Nettelroth, II, 36 II, 11, 35 s. lluni^erfoi'iU, Hall, 11,23,25, 37 II, 29, 30, 31, 39 s. imbrex. Hall, . 11, 20, 38 II, 14, 35 s. iucertus. Hall, . 11, 26, 38 II, 19, 37 s. increbescens. Hall, • II, 27, 39 II, 19, 37 s. increbescens, var. Amerii^auus, Swallow, II, 39 • n, 30 s. increbescens, var, transversalis Swallow, II, 33 • II, 27, 38 s. Keokuk, Hall, . . 11,27, 38 II. 37 s. Knappianus, Nettelroth, , II, 36 II, 17, 36 s. la-vis. Hall, , II, 19, 33, 37 II, 20, 38 s. Lamarcki, Fischer, I, 215 II, 36 s. lateralis, Hall, . II, 26, 38 II, 19, 37, 360 s. Leidyi, Hall, . II, 27, 39 II, 211, 38 s. Leidyi, var. Chesterensis Swalloiv, II, 39 II, 38 s. Leidyi, var. Meramecensis, SiikUIoil; II, 39 II, 57 s. ligus, Otoen, . .n,3i, 39 II, 21, 37 s. lineatus, Martin, II, 10,11, 17, 21, 30, 37 II, 24, 27, 38 s. Littoni, Swallott; . II, 27, 38 . II, 10, 36 s. Logaui, Hall, . . 11, 23, 38 II, 34, 40 s. Macbridii, Calvin, 11,29,31, 39 I, 255, 256, 257 s. jVIacconathi, Nettelroth, II, 39 II, 360 s. macroideura, Conrad, , . U, 13, 35 II, 19, 20, 30 s. macrothyris, Hall, n, 29, 31, 39 INDEX. 391 Spirifer raacrus, Hall^ s. Mai.1, Billings^ . s. Manm, Hidl, s. Marcyi, Hall, . s. Alarcoui, Waageii, s. Marionensis, Skumanl, s. jnedialiSf Hall, s. medianus, QimisteJt^ . s. inesacostalis, HM, s. niesastrialis, Halt^ s. Jleta, Hall, s. Missourieusis, Sicallow^ s. niodestus, Hall, . s. l^Iortonanus, Miller, s. Mosf|uensis, Fischer, s. mucrouatus, Conrad, . s. mucroiiatus, var. jjosterus, s. multistriatus, Hall, s. Musakheylcnsis, Davidson, s. neglectas, Hall, s. Ne^vberryi, Jlult, s. Niagarensis, Conrad, . s. nobilis, Barrande, s. nymp'ia, Bdlings, s. OceanI, d'Orbi^^iiy, s. ootocostatus, Hail, s. opimus, Hall, . s. Orestes, Hall, . s. ostiolatus, Schlotlieiin, • s. Oweui, Hall, s. Panyauus, Halt, s. jjerextensus, Meek and Won s. l)erlamellosu3, HaJl, . s. perplexus, McCliesney, . s. planoconverits, Shumard, s. plenus, Hall, s. plu'atellus, Dalnuin, s. Pluto, Clarke, s. porambonites, voil liuch, s. pi-cmaturus, H(dl, , s. propinqutts. Hall, s. pseudolineatus. Hall, . s. py.ivlatus, Hall, s. Quichua, d'Orbigny, s. radiatus, Sowerby, s. rai'ioosta, Conrad, s. rostellatus, Hall, s. rostellum, Hall amiVriiitfield, s. SaBordi, Hall, . s. Schmidti, Limlstram, . s. scuIptlUs, Enll, . s. scgmentus, Hall, s. senilis, Phillips, s. scti^'crus. Hall, , s. simplex, Phillips, s. sp. iiides.. s. striatiformis, Meek, s. atriatus, Martin, s. subajqualis, Hall, s. subattenuatus, Hall, . s. subcardiilormis, Halt, . s. subcuspidalus. Hall, . s. submucronatus. Hall, . II .II, .11, .II, .II, .II, .II, .II, .11, II, a, II. u, .II, .II, .II, .II, .II, • II, .II, • II. II, 20, II, 29, II, 14, .II, II, 31, . II 33 23 34 3G 35 35 38 37 38 23, 25 17, 36 II. 361 II, 12U •II. .II, ■ II, .II, .II, .II. .II, .11, , 10,21, .II, .11, • II. .II. II. 31, 2fi> U. li, II, n, 19, 27, 27, 1-', II, 31, 31, 26, 21. n, •39, 9. II. II. II. n. 21, II, II. 13. 16, II. U. 19, li, II, 17, 26 39 38 33 57 37 39 38 28 23 39 38 35 37 56 48 13 39 227 37 50 37 SG 276 35 36 26 35 36 35 36 36 I, 262 21, 30, II. 25, 23, 26, 17. 26, II. I", PAGE. Spirifer suborbicularis, EaU, . . II, 26, 38 S. subrotuudatiis. flail, . . II, 38 S. subunibona, Hall, . II, 34, 40 S: subuiidilcrus. Meek and Forthen, . 11,20,21,33, 37 S. sulcatus, Jlisinr/er, . II, 16, 3o S. tegulatus, Trautscliold, II, 2« s. teuuicostalus, Halt, . .11, ii;. 38 s. tenuiiiiarjfiiiatus, Hull, II, .38 s. texanus. Meek, . . 11. 26, 38 s. textus. Hall, II, 50 5. transiersus, McCliesnoy, II, 54 s. Iribulis, Halt, . . II, 19, 37 s. TscheJJ'kini, de A'enieuil, II. 22», 229 s. Tullius, Halt, . .11,14, 35 s. undiferus, F. Itoemer, II, 33 s. unicus, Hull, . 11, 24, 37 s. urbamis, Culvin, .11,19, 37 s. A'auuxemi, Halt, . II, 19, 36 s. varicosus, Conrad, . n. 17, 3« s. ventricosus. Hall, . 11, 144 s. ? Waldronensis, Jlillcr and Dyer, I. 272 s. Whitlioyi, Halt, .11,24, 57 s. AViUiamsi, sj). nov , 11,27, 38, 3U1 s. AVurtlu'iiaiius, Srkur.liert II, 36 s. Wortheni, Hall, .11,31, 39 s. zic-zac. Hall, . 11,16, 3« s. ( Cyrtial) Hunnibalensis, Swallow, II, 50 s. (Syringothyri--) Carteri, Hall. II, 8 Spirifcriua austriaca, Suess, . • 11. 15 S. Billiiigsi, Sftuiiuird, II, 54 S. binacuta, Winrhell, , II, 54 s. Clarksvilleiisis, WineMl, II, Sk s. cristata, Schtotheim, . II. 1". 5t s. cristata, var. octoplirata, . II, 17, 54 s. iusouipta, rhiltips. • U. 17, 54 s. Kentuckiensis, Snumard, , 11,17,52, 54 s. Kentuckiensis, var. prop. itula, Sicfi tow, . 1 1, 64 s. Kocsscnensis, Zugmayer, 11, 45 s. rostrata, SchUiilieim, . .11,62, S3 s. solidirostris, White, • II, 17, 54 s. spincsa, Norwood ami Pratten, II, 52, 53, 54 s. .spinosa, var. campcstris, White, . II. 54 s. subelliptioa, McChestney, II. 46 s. subtexta. White, II, 64 .s. Suessi, mnkler. n. 15 s. transversa, McChesney, . II, 40. 61 s. uucinata, Schtotheim, . II, 45 s. Walcotti, Sowerby, II, 53 Spirigerella alata, Waagen, . II, 99 S. Derbyi, Waagen, II, 98, 99, 100 S. lusiformis, Waagen, II. 9i S. srrandis, Waagen, II, 98 s. hybritia, Waagen, 11, 99 s. media, Waagen, 11, 99 s. iiiluuta, Waagen, II, »i s. numismalis, Waagen, . 11, 99 s. ovoidalis, Waagen, II, 98 s. • pr.-elongala, Waagen, . II. 99 .Stcuoschisina formosa. Hall, . II, ISU Stiept is Grayi, Davidson, I. 274 Streptorhynchus cardinalis, Whitlield, I, 232 S. Correanus, Derby, . I, 262 s. crenUtria, I'hillips, 1,256,257, S«S 392 INDEX. Sireptorhynchus crenistria, var. seni7is, Phillips, S. eusarcus, Ahich, S. llallianus, Derby, S. iiicurvus, Abich, S ? lepiduSy Schiiur, S. occiilcntalis, Newberry^ S. Pandora, Billings, S. pectiniformis, Davidson, S. pelargonatus, Schlotheim, S. 7 pHmordiale, WhiLIieM, S. pyramidalis, Newberry, S. tenuis. Hall, S. Uli-ichi, sp. nov., Slriclvlandinia Anticostieiisis, Blllhigs, S. 1 Aracline, Billings, . . . H, S. Areihusa, Billing's, . . -Hi S. ? Jiatcletchensis, Davidson, S. hrev is, Billinys,. S. Canadensis, Hillings. . S. castollana, JVJiite, S. Davidsoni, Billings^ S. deformis, Meek and 'Win-tlic S. Gaspensis, Billings. . S. Melissa, Billings^ S. multilirata, WiUfield, . S. Salteri, Billings, Stringocephalus Burlini, De/rance, S. Bohemicus, Barrande, Strophalosia cxcavata, Geinitz^ s. Goldfussl, Miiiister, 8. Keokuk, needier. S. lamellosa, Geinitz, s. Leplayi, Geinitz, s. numularis, A. Winchell, s. parva, King, s. plicosa, Wnagen, s. radicans, A. WincheU, . s. Rockfordensis, sp. nov., s. scintilla, Beecher, Stropheodonta arcuata, Hall, . S. Becki, Hall, S. Blaiuvillii, Billings, . S. Calvini, Miller, . S. Canaee, yja/( and mdtfield S. Cayuta, Hall, . S. demissa, Conrad, S. iilosa, Davidson, S. inwquistriat.a. Ball, S. Irene, Billings, . S. Junia, Sail, s. Leblauti, iJoMauW, s. magnilica, Hall, s. magni\'entra. Hall, s. nacrea, Hall, s. perplana, Conrad, s. profunda, Hall, . s. textilis, Hall, . s. Tullia, Billings, s. variabilis, Calvin, Strophodonta fasciata, Hall, . S. striata. Hall, Strophomena alternata, Conrad, S. antiquata, Sowerby, PAOE . I, 316 I, 2G3 I, 265-208 I, . I, 25!), . • I, I> . I, 2Go, , 203, 207, I, I. I, . I 268, II, , 213, 213, 313, 213, II, 231, II. . II. II. II. II. II, 350, 203 260 20G 255 208 208 231 366 355 351 251 251 251 341 351 251 25i 251 251 251 251 251 251 285 II. II, II. 2S3 284, II, I. I. 316, 320, I. I. I. I, I, 316, 320, . I, 316, 353 316,320, 336 I, . I, 386, I. I, I. I. , 2S7, 289, I, I. I. I. I. I, 286, I, I. . I, 388, I. I. I. I. I. I. 143, 148, 219, 350, 389 388 388 387 387 287 292 250 289 288 288 307 288 Strophomena cameraia, Hall, -. S, carinnta, Conrad, S. Chemungensis, Conrad, S. clausa, de Verneuil, . S. Conradi, sp. nov,, ST. deflecta, Conrad, .S, depressa, Dalnian, fi^. Dulcrtrii, Murchison, . S, miglyplm, Dalnian, S. expansa, Sowerby, S. explanata, Sowerby, . S. Jilosa, Sowerby, . S. fluctuosa, Billings, S. fuuiculata, Jt/cCo7/, S. grandis, Sowerby, S. Hallie, Miller, . S. Hecuba, Billings, S. Hendersoni, Davidson, S. Holli, Davidson, S. Jitkesi, l-)avidson, S. Kingi, Whitfleld, S. laticosta, Conrad, S. Lehlanci, llouault, S. Leda, IJiUings, . S. lepis, IJronn, S. MinnesotCTisis, X. H. Winchcll, S. Narajoana, do Verneuil S. nitens, BMlini^s, . 3. ? jtalma, Kayser, . S. patenta. Hall, . S. pccten. D.alman, S. Philomela, Billings, S. planoconvexa. Hall, . S. jilanunibona, Hall, S. recta, Conrad, . S. rhomboidalis , Wilckens, S. rugosa, llisinger, 5. SiluriaTia, Davidson, . S. sinuata, Emmons, S. squamula, James, S. Steini, Kayser, . 5. subptana, C'onrad, S. subtenta, Conrad, S. Thalia, IJilliugs, S. Ulrichi, James, 5. unicostata. Meek and Worthen, S. Winchelli, sp. nov., S. "W'isconsinensis, JVliitfield, S Woolworlhana, Hall, . S. (Lepta-na) planumbona. Hall, Strophomenesjlexilis, Rafinesque, S. levigata, Ralinesque, . Stroplionella ampla. Hall, S. s. s. s. s. s. s. s. s. s. CKlata, Hall, cavunil)ona. Hall. Conradi, Hall, . costatula, sp. nov., euglyplia, Dalman, funiculata, Smcerhy, . Headleyana, Hall, Leavenworthana, Hall, patenta, Hall, . puuctulifera, Conrad, . I, UK. 283 II. 304 I, 355 I, 387 I, J44r I, 197 I, 349 I, 349 1, 349 I, 249 I, 288 I, 349, 388 I, 251 I, 219 I, 349 I, 352 I, 252 I, 283 I, 283 I, 283 I, I, 283 306 I, 287 1, 288 I, 287 I, 283 I, 287 I. 283 I, 288 I, 291 r, 249 I, 288 I, 249, 251 I. 249, 265 I, 197 7,2 18, 249, 350 1.2 50. 251, 252 I, 283 I, 251 I, 383 I, 388 I. 255 I, 251 I. 251 I, 283 I, 282 I, 34:4: I, 251 I, 255 I, 249, 252 1.2 48, 3t9, 252 I. 248, 252 I, 291, 293 I, 291, 293 I, 291, 292 I, 292 u. 359 I, 260, 292 I, 259, 292 I, 292 I, 291, 292 1, 291, 292 1,291, 292 INDEX. 393 Strophonclla radiata, ffall^ S reversa, ITaU, S semifasciata. Hall, . S. striata, Jlall, Synirielasma hemiplicatum. Hall, S}Ulrul)liia lati-'ialis, W hit field, Syringothyris angulata, Simpson, Carteri, Hall, cuspidata, Martin, distans, McCoy, Halli, WinchcU, . Herricki, Schuchert, Missouri, sp. nov., Randalli, Simpson, texta, Hall, typa, A. WinchcU, Terebratula Adricni, du N'enicuii, T. amiigdalina, Goldrurf.>, T. Andii, d'Orbiguy, T. Ajitisiensis, d'Orbigny, T. Archiaci, de Verncuil,. T", boindens, Morton, T. Jlurlin'jtoncnsis , Wliitc, T concentrica, von Uucli, T. cuneata, Dalman, T. deflexa, Sowcrby, T. didyma, Dalman, T. fcrita^ von Bucli, T. formosa. Hall, . T. Gaudryi, tVOvhigny, . T. Gcinitziana, de Verneuil, T Guerant/eri, de Verncuil, T Ilarmonia, Hall, T. Mimalayensis, Davidson, T. herculca^ iJarraude, . T. loivensis, Calvin, T l(Bviuscula, Sowerby, . T. latilinguis, Suhnur, T. lens. Hall, T. Icpida, Goldfuss, T. Lincklani, Hall, T. viclonica, Barrande, . T. Michelini, d Orbigny, . T. mitlipuvctata, Hall, . T Mormoni, Marcou, T. navicula, Sowerby, jT. ovoides, Eaton, . T. planirostra, Hall, T. reciirtjsfra. Hall, T rhomhoidea, PbiJliiJS, . T, Romingeri, Hall, T. Roivlcyi, Worthen, T. saccnlus, Martin, T. Schlothcimi, von Buch, T. simulator. Hall, T. Stolcesi, Koenig, T. Striclclandi, Sowerby, T. strigiceps, F. Roemer, T. sublepida, de Verneuil, T. subvescicularis, Davidson, T. Sullivanti, Hall. T. iurgida, Hall, . T. rcnusta, Schnur, PAGE. PAGE. I. 292 Terebratula vescicularu, ile Kuninck, II, 291 1,291, 293 T virgo, I*hilU])S, . 11, 271 l.'-ai. 292 Terebralulina sc'iilciilrionalis, Lintie, I, 18; II, 328 1,291, 292 TerchrataiUes (cquirostris, Sclilothcim, 11. 227 I, 210 T. bi/oratus, S ;lilotheim, . I, 200, 20 11, 213 T. elon^aius, Schlulliciin, 11, 29i 11, 30 ^- U^yphus, Scliiotliciiu, . II, HI n, 60 T. pelargonatus, SclUolheim, . I, K7 II, 50 T. rostrulus, .SchlQthcim, ~ . II, 52 11, 50 T. Schlothcimi, von liuch. II, 216 11. 51 Tcrebratuloitlea Uavid.soni, M^aagen^ U, 209 11, 50 Tetractiiicila triEonella, Schlotheim, II, 100 11, 50 Thcciflca Jlcditcrrauca, Kowalevski, K, S2S II. 50 Trematis Bohemica, llainiiulo, . 1,40, 142 11. 50 T. caiiccllata, Sowerby, . I, 112 IJ , 8, 48, 50 T. <-oi(iiia, Salter, . I, 112 . II, 1 D3, 101, 273 T. crasbiimncla, Ulrich, . I, 112 II, 2G1 2S1 T. Dycri, Miller, . I, 112 I. 217 T. fragilis, Ulrich, I, 142 II, 276 T. lluronensis, liilltngs, . I, 142 11, 280 T. millopunctata, Hall, . . I, J39, 14J II. 2!Jl T. iloiitrcalcusis, llillinga, 1, 112 11. 296 T. oblata, Ulrich, . I, 142 11, 87, 90 T. OttawacnsL., Billings, . 1, 139, 142 11, ISO T.l pannulus, Wlnla, I, 94 II, 224 T. puiK^tala, Sowerby, I, 141 11. 60 T. punctootriala, Jlalt, . I, 142 n. 112 T. pustuloia. Hall, 1, 142 II, 2'IU T (iuiucuncialia, Miller itnd liyer. I, 142 . 1,2 17 ; II, 273 ?? T. rudis, Uall, .1,112, 144 II, 210 T. terminalis, Emmons, . 1, 139, 140, 142 II, 258, 2 60, 207, 272 T. umbonala, Ulrich, I, 139 II, 290 T. (Scfaizocrania) sui)eriucrota, Barre tt. I, 144 II, 299 Trcmatobolis iusignis, Matthew, 11, 324 11, 71 Truiiiatoipira Acadia;, Hall, . . II, 127 11. 297 T. camura. Hall, . 11, 120 II. 97 T. cusia;a, Hall, . U, 126 II. 175 T. Deweyi, Hall, . 11, 128 II. 2S6 T. dubia, Billings, . U, 126 II, 130, 131, 1 33, 134, 135 T. gibbosa, Hall, . 11, 127 . n,2 86, 290, 296 T. Hippolyte, Billings, . II, 126 II, 288 T. hirsuta. Hall 11, 127, 128 I, 217 T. infrcqucns, Walcott, . 11, 127 II. 301 T, liniuscula, A Winchcll, II, 127 II. 120 T. Maria, BUlings, II, 126 II, 62 T. Mattlicw.ioni, McChesney, . . 11, 1-27 II. 267 T. multiatviata, Hall, II, 126, 127 II. 280 T. nobilis, Hall, . . U, 127 11, 2S0 T. perforata. Hall, II, 126 II, 216, 217 T, quadriplicata, iMiller, . II, 185 II. 297 T. simplex, Halt, . II, 126 II, 290 Trigcria Guerangcri, de rerneuit. II, 273 II. 300 Trimorella acuminata, BUlings, . 1,35, 30 II, 187 T. Billlngsi, Dall, .11,35, 38 II. 290 T. DMi, Datidson -.ukI King, . I, 85 II. 8 T. grandis, Billings I, 34, 35, 30 II. 199 T. Lindstrccmi, IMlt, . I, 34, 30 ; II, 3-22 II, 2C0 T. Oliioensis, Meek, I, 34, 35, 36 II. 103 T. Wisbycnsis, Varidson and King, I, 36 . II, 275 Triplecia extans, Emmons, . 1,270,271, 273 II, 290 T. Orloni, Meek, . 1,208,270, 271 II. 294 Tnplesia cuspidata, Hall, I, 271 . II, J 30, 131, 131 T. ? Grayia;, Davidson, . . .1,270, 271 394 INDEX. Triplesia lateralis^ Whitfield, T. Maccoyan.i, Davidson, T. nucleus, Tlallt T. primordialis, Whitlii'M, T. putUlus, Hall, . T. radiala, JfhitJieUl T. AVenlockonsis, Davidson, Tropidoleptus oarinatus, Coju-ad, T. occulens, JIallf Uncinella indica, }Faaffen, Uiicinulina (allat-iosa, Baylc, . Unciuulus sub-Wilsoni, d'Orb'niy, Uncites carbouariuj;, Quenstedt, U. Galloisi, (Ehlert, U. j^ryphus, Schlotheim, . U. Icevis^ illcCoy, . VituUna pnstulosa, Halt^ Volbortliia Rxurva, Katvrya, PAGE, PAGE. . 11,212,213, 251 Wliitllelclella cylindriia. Unit, 11. 61 I, 270 W. intermciUa, Hull. II. 61, 160 I, 271 W. n.lvilVirmis, //(///, II, 160 1.271; II, ■214 W. m{h]:i.JIaU, .... II. 61 I, 272 Waldheimia formoaa. Hall, II, 110 I, 271 W. globoaa, Hall II, 111 I, 270 W. rectirostra, Hall, II, III . I, 148 ; 11. 137, 138, 140 W- Deweyi, Hall II, 128 304, 305 Zdimir solus. IJun-ande, II, 235 II, 30li Zygospira 1 nquila, Saideson, . II, 150 11, 110. 123 Z. Cincinnatieusis, jl/ee/:, II, 156, 167 11, 193 Z. conconti-ic-a, Ulrich, ■ II, 157 II, ino Z. unatica, Uall, . . . I, 157, 169 II, 114 Z. Kentuckicnsis, James., [I, 156, 157 11, 115 Z. minima, DiUings, II, 157 II, 114 Z. mo^\es\.a., (Say) Hall, . II, l.'iS, 1S6, 167, 158, 163 II, 115 Z. ]>aupera, Billings^ II, 157 II, 137, 138, 139 Z. putiUa, sj). nov , II, 157, 365 141 Z. recurviroslra. Hall, . I, 151, 156 ■ I. 95 Z. Uphami, Winchcll aui-1 Schuchert, , 11. 157 PLATES AND EXPLANATIONS. PLATE XXI. (Figures 1-29 by !l. P. Whitkikm).) Leg-end : A- Delthviiuui. c. Ci-uni. D. Deltidiuin. s. Median septum, t. Teeth. s'. Callosity in the ;. Diductor scai-a. t Teeth '^ ■ Socket-walls, s'. Median lidge. J- Cardinal process, s', s". Callosity in delthyriiim. 1). Dental sockets. Gends SPIRIFER, Sowerby. Page 1. Spikifek Oweni, Hall. Fig. 1. Dorsal view of a normal adult. Fig. 2. A protile of the same. Fig. 3. The interior of the cardinal portion of a brachial valve ; showing the dental sockets and socket- walls. Fig. 4. A portion of the interior of the pcdicle-valve ; showing the apical callosity, and the scar of the diductor mnscles. Fig. 5. A corre.sponding portion of a smaller shell of this species. Fig. 6. The interior of the cardinal poi-tion of two valves in articulation, the pedicle-viilve lying beneath. Fig. 7. An enlargement of the surface from a worn specimen. Hamilton group. Clarlie county, Indiana. Spibifek Pakkyanus, Hall. Fig. 8. The usual form of the shell ; the cardinal area being foreshortened. Fig. 9. An enlargement of the surface chai-actei-s. Limestones of the Hamilton group. Davenport, Imva. Fi'rs. 15, 16. Two vievv's of an internal cast. This is the con• Dental Bockets. I). Deltiiiiiim. c'. Socket-walls. Dg-. Deltidial grooves. a. Anterior aildnctors. t. Teeth. a'. Postei'ior adductors, s'. Ajiical callosity. r. Diductors. j. Cardinal process. Genus SPIRIFER, Soweury. rage 1. Spirifek audaculus, Coiuail. Fig. 1. A small individual of normal proportions. Fig. 2. A brachial valve of an average example. Fig. 3. The pedicle-valve of a rotnnd specimen. Figs. 4, 5. Dorsal and profile views of an individual with short hinge and fewer plications. Fig. 6. Front view of an average adult. Fig. 7. The inteiior of the brachial valve ; showing the aiticnlating apparatus and muscular scars. Fig. 8. A cardinal portion of a larger brachial valve ; showing the same strui-turea more distinctly. Fiu-. 9. The intei'ior 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, retaining the remnants of the ilel- tidial covering. X 2. Fig. 11. A similar view of another example ; showing the high development of the delthyi-ial callosity. Fig. 12. A part of the brachial valve ; showing the cardinal process, articulating ajiparatus and the char- acter of the adductor scars. X 2. Pig. 13. An enlargement of the extei-n.il surface ; showing the grooves on the summits of the plications. Hamilton shales. Western New York. Spirifek angustus, Hall. Figs. 14, 15. Dorsal and ventral views of the exterior of a rather large imlividual. Fig. 16. A cardinal view of the same specimen. Fig. 17. An enlargement of the external surface ; showing the flattened plications and incipient grooves. Spirifer audaculus, v.'ir. macronotus, Hall. Fig. 18. A cardinal view of a large individual which retains the deltidial covering in a broken condition. Fig. 19. A cardinal view of a shallower, more extemled individual. Fig. 20. A protile view of the same. Fig. 21. A view of the interior of the pedicle-valve, looking into the unibonal cavity ; showing the callosity and dental plates. Fig. 22. Central portion of the cardinal area; showing the highly developed delthyi'ial callosity. X 2. Fig. 23. A similar view of another specimen in which the deltidial covering is retained in a broken 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.'5. The interioi' 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. HaLiilton shales. Wester7i Neio YwJc. lEJ Ji j^ S, mi 2 ® IP iiD 10 JX. . Spiriferidae. Palaeont . N.YVol IV, Pt ji (iciii'iii- Illustrations; Plate XXr? f i Fig-. 2. Fig. 3, Figs. 4, Vig. 6. Fig-. 7, PLATE XXV. (Kiftures 1-8 by F. B. Mkkk; U-IC, 22--24, 2ii-31 by U. P. Wuitkield; 17-'.;1, 25, 32-35 by E. EMMONS.) Le^tnii : i\. Delthj rium. j. Cardinal process. Dg-. Deltiiiiiil groove. b. Dental sockets, s'. Apical callosity or lube. c. Socket-walls, s. Median septnni. a. Anterioi' addudors. d. Dental JaToell!!'. a'. Posterior adductors. Genus CYRTINA, Davidson. ra^c 43. Cyrtina KOSTRATA, Iltlll. Fig. 1. A front view of a specimen .somewhat below average size. 2. A cardinal view of the same; showing the tubular edge of the median septum within the delthyrium. A bi'achial valve of a larger example. 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. The interior of a brachial valve. The interior of the pedicle-valve, looking into the umbonal cavity ; showing the convei'gent dental lamells, their union with the median septum, and the tubular edge of the latter. Oriskany sandstone. Albany comity, N. Y., and Cuinberland, Md. Genus SPIRIFER, Sowerbv. I'Mge 1. Spirifer Macbridii, C'alviii. Fig. 9. The exterior of a brachial valve. Fig. 10. The exterior of a pedicle-valve, somewhat foreshortened ; showing the faint jilication in the sinus. Fig. 11. A carilinal 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 composition of the musculai' area. X 2. Fig. 13. The interior of a pedicle-valve ; showing the development of the dental plates. Fig. 14. The interior of a bi'achial valve retaining the spiral cones; showing their position, number of volutions and the anterior portion of the long crura. Figs. 15, 16. Enlargements of the surface ; the former fi'om the lateral i>lications, the latter iVom the median sinus. Hamilton group. Mockford, Iowa. Si'iKiFER s;)., coinp.iri! S. Macbridii, Calvin. Figs. 17, IS. Views of the exterior of a sjiecimen, with two low, bioad plication.-; iin the median sinus, and having a somewhat different aspect than normal examples of S. Macbridii. Fig. 19. An enlargement of the surface, which ia covered with radiating rows of elongate pustules, distinctly coarser than in iS. Macbridii. Hamilton gi'oup. Probably from the blue shales at Mod Ls'land, Illinois. SpnUB'ER ASl'ER, Hall. Fig. 20. The fi-ont view of a normal individual. Fig. 21. The exterior of a brachial valve. Hamilton gi'oup. NeiB Buffalo, Iowa. Fig. 22. A pedicle-valve viewed from at)ove. Fig. 23. The cardinal view of a pedicle-valve with highly developed delthy rial callosity ; the central extension concave on the inner side; .showing the incipient stage of the canaliferous tube of Syrimgothtris. Fig. 24. An enlargement of the surface. Hamilton group. Rockford, Iowa. Fig. 25. The exterior of a pedicle-valve, pi'obably representing this species. Hamilton grouji. Canandaigua, N. T. PLATK XXV— Continued. Genus CiTRTIA, Dayman. Page 40. Cyrtia cyrtiniformis, H.ill and Whitfiekl. Fiffs. 26-28. Three views of a normal example ; ehowing the extei-nal characters. Fig-. 29. A cardinal view ; showing the great height of the area. X 2. Fig. 30. The central cardinal portion of the conjoined valves ; showing the dental plates of the pedicle- valve, the cardinal process and socket-walls of the brachial valve. X 2. Fig. 31. The interior of a portion of the brachial valve ; showing the cardinal process, dental sockets and socket-walls, and the subdivision of the muscular area. X 3. Fig. 32. A specimen, showing the crura, jugal processes and spiial cones. Hamilton group. Hockford, Iowa. Genus SYRINGOTHYRIS, A. Winchell. rage 47. Syringothyris Hannibalensis, Swallow. Fig. 33. The exterior of a portion of the brachial valve. Fig. 34. A cardinal view of the pedicle-valve ; showing the dellhyrial callosity or canaliferous plate. Fig. 35. The articulating apparatus of the brachial valve. X 2. Choteau limestone. Pike cauntij, Missouri. 1E3 "J^i ^ :B S 2 I) :P ffl ID -^ . Spiriferidae UcniTi" llUisli.ilm Falaeont N Y Vol lYPt w =Vol Vin. Plate XXV E.Emmons del. pha.Asilith. PLATE XXVI. (Figures 1-7, 9-11 by R. 1». Whitfield; 8 by F. B. Meek; 12 by E. Emmons.) Legend: A. Cardinal area. T'. Internal cast of tube. A. Delthyriiim. j. Cardinal process. Dg. Deltidial grooves. b. Dental sockets. s'. Transverse delthyrial plate. r. Didiietor scars. T. Tubulai- portion of plate. a. Adductor scars. Genus CYKTIA, Dalman. Page 40. Cyrtia alta, Hall. Fig-. 1. The internal cast of the brachial valve ; showing- the striated cardinal area, structui-e of the artic- ulating apparatus and the faint plications on the inedi.in fold. Fig. 2. The front view of an internal cast of the pedicle- valve; showing the muscular area and the faintly plicated sinus. Fig. 3. An exterior view of the cardinal area of the pedicle valve ; showing the concave plate filling the upper part of the delthyrium. Fig. 4. A cardinal view of an internal cast of the pedicle-valve ; showing the impi-ession left by the thickened inner wall of the delthyrial plate. Fig. 5. A portion of an internal cast of a small brachial valve retaining traces of the muscular sears. Chemung gi-oup. Meadville, Penn. Genus SYRINGOTHYRIS, A. Winchell. Page 47. Syringothyris typa, a. Winchell. Fig. 6. The apical portion of a pedicle- valve ; showing the dental plates, the delthyrial plate, with the central tubular portion projecting beyond its broken margin. Fig. 7. The opposite side of the same specimen ; showing the extension of the canaliferous tube which is slit along its inner surface. Fig. 10. The interior of the umlxmal portion of the pedicle- valve; showing the greatly thickened tubulai- or canaliferous plate, not closed along its inner surface. Burlington limestone. Burlington, Iowa. Syringothyris subcuspidatus, Hall. Fig. 8. A cardinal view of the original specimen. Keokuk limestone. Keokuk, Iowa. Fig. 11. The interior of a large pedicle-valve ; showing the transverse plate and the extension of the tube. Keokuk group. Nauroo, lUinoi.^ 16 |«^% /Zf- ■»»:« 28 ...rf?^ '' 4 jir^ r\,r V.^.itfieid del Phil.AstUih. PLATE XXX— Continued. SriRiFER Orestes, Hall mid Whitlickl. Fig. 20. A normal adult imiividual. Chemung' group. Rockford, lo^oa, Spirifer Keokuk, Hall. Figs. 21, 22. Views of a normal inilividual. Keokuk group. Keokuk, Iowa. Fig. 23. A small example, with short, rounded cardinal extremities. Keokuk group. Lizard Creek, Iowa. Fig. 24. A specimen with extended hinge ; showing the extreme of variation in form. Keokuk group. Marion county, loxoa. Spirifer Leidyi, Norwood aiul Pratteii. Figs. 35, 26 Dor.sa! and profile views of a normal example. Chester limestone. Chester, Illinois. Spirifer increbescens, Hall. Figfs. 27, 28. Dorsal and profile views of a rather large shell, with relatively short hinge. Fig. 29. A smaller individual, with more extended hinge-line. Fig. 30. Enlargement of the surface characters in this species. Chester limestone. Chester, Illinois. PLATE XXXI. (FigureB 1-3, 6-10, 12, 15, 18, 19 by 11. P. Whitfield; 4,5, 11, 13, U, Hi, 17 l)y K. B. Meek.) Legend : A. Cardinal area. j. Cardinal process. Adt. Denticulat(!d cardinal margin. b. Dental sockets. D{f. Deltidial grooves. a. Adductor scars. s'. Callosity in delthyriiim. r. Diductor scars. t. Teeth. Genus SPIKIFEK, Sowerby. Page 1. Spikifer increbescens, Hall. See Plate 30. Fig. 1. A portion of the interior of the pedicle-valve ; showing the denticulatioiis along the cardinal mar- gin, the delthyrial 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 cardinal edge of the pedicle-valve. The surface of the shell on the area is somewhat exfoliated, exposing the series 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, lUbwis. Sfirifek opimus, Hull. Figs. 4, 5. Bi'achial and profile views of a normal individual. Coal Measures. Iowa. Fig. 6. The interior of the pedicle-valve ; showing the character of the muscular impression. Fig. 7. The interior of a brachial valve. Coal Measures. Bomjardim, Brazil. Spirifer Grim ESI, Hall. Fig. 8. A cardinal view ; showing the high, relatively short area, and the convexity of the valves. Fig. 16. Dors.al 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 impre.ssions of the adductor and liiductor muscular scars. Fig. 19. Enlargement of the radiating surface stris. Bui-lington limestone. Burlington, Iowa. Spihifer Newberryi, s[). nov. Fig. 9. The exterior of the brachial valve ; showing the fine plications. Fig. 10. An enlargement of the surface ; showing the fine striae. Waverly group. Oliio. Spirifee 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 striae. Burlington limestone. Burlington, Iowa. Spirifer sub^qualis, Hall. Figs. 13, 14. Cardinal and dorsal views of the original specimen ; showing the imbricated exterior. Warsaw limestone. Warsaw, Illinois. Spirifer Marionensis, Shuniaid. Fig. 15. A view of a rathei' small example ; showing the fasciculate plications. Choteau limestone. Pike comity, Missouri. 113 :3i J^ 'r: :m. :l 13 :3' D 's) Js. Palceont.Ny.Vol.lV.Ptii S Dint en dee. Generic Ulustralions Plate XXXI, R-P WhitiiT!'! dc: Phu Aei hOi. PLATE XXXII. (Figures 1-3, 7-10, 12-15 by [i. P. Whitfield; 4-«, 11 bv F. B. Meek.) Legend : A- Delthyi ium. a. Anterior adductoi'S. t. Teeth. a'. Posterior adductors, s. Delthyrial callosity. r. Diductors. Genus SPIRIFER, Sowerby. I'age 1. Spirifeb lateralis, Hall. Fig. 1. Dorsal view of a large and rather convex individual. Fig. 2. Front or mai'ginal view of the same specimen. Fig. 3. An enlargement of the surface ; showing the pustulose stria; on the plications. Warsaw limestone. Warsaw, Illinois. Spirifer tenuimarginatus, Hall. Figs. 4, 6. Views of an individual of normal size. Keokuk group. Keokuk, Iowa. Spirifer rostellatus, Hall. Fig. 5. A dorsal view of the original specimen. Keokuk group. Skunk River, Iowa. Spirifer Logani, Hall. Fig. 7. A dorsal view of the original specimen ; showing the gi-eat size and general external characters of the species. Fig. 8. The interior of a portion of the pedicle-valve j showing the articulating apparatus and the adduc- tor and diductor muaculars scars. Keokuk limestone. Near Naiivoo, 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. Fig. 11. An individual with broad, low fascicles composed of rounded plications. The breadth 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 fig. 11, indicate the extremes of variation in exterior in this species. Fig. 13. An enlargement of a portion of the internal 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 extremely fine concentric striiB, which are minutely papillose. Distinct imbricating lines of growth supervene towards the anterior margin. Coal Measures. OMo and Illinois. _ !n3!fi^S:u:313J^ DnD^ Palaeont.NYVoHV.Ptii bpinieridcP Cipiicrir nhii>Ira1ions ,y/fifi Plate XT/OI "4TiH» .^'^S. '"^:^-: , m' k /if^V ^^sr^f^ha^ #' 2- \ jlftltiiiii'^tlfiii 'm '-^ ^ '■^hitfieid d- f. Fissure at base of dental sockets (brachial valve). g- Rostral callosity. )>. Dental sockets. c. Crura. sp. Spirals. a. Adductor scars. 1-. Diiluctor scars. PLATE XXXIII. (Figures 1-23, 27 by R. 1". WiiiTriELD; 2l-'2(; liy F. B. Mkkk.) Legend : A. Cardinal area. D. Deltidium. f. Foramen, t. Teetli. s. Median sejitum. s'. Deltliyrial callosity. D}f. Marj,'iiis of deUliyrium (brachial valve). Genus SPIRIFER, Sowerby. l»a;;e 1. Spirifer tkibulis, I hill. Fig-. 1. The exterior of a brachial valve of an average example; showing the lamellose surface. Fig. 2. The exterior of a brachial valve. Fig. 3. The interior of a i)eilicle-valve ; showing the character of the muscular area. Fig. 4. k cardinal view of conjoined valves ; showing the elevation of the area. Oi'iskany saii' % 1 CiS ^^ J b .<■ r A - -":-M^ * 21 J^^-^^_ /-.' IP Wlu;f:s!d d«l PLATE XXXV. (Figures 1-29 by R. P. Whitfield.) Legend ; D. Deltidial plates. j. Cardinal process. /I. Delthyriuin. b. Dental sockets. F. Foramen. c. Crura, t. Teeth. a. Anterior adductors, d. Dental lamellae. a'. Posterioi- adductors. X. Pedicle-cavity. r. Diductors. s. Median septum. Grnus SPIRIFER, SowEKiiY. Page 1. Spirifer sulcatus, HLsinger. Fig-. 1. An inilividual of normal proportions ; showing- the lamellose exterior. Figs. 2, 3. Enlargements of the central portion of the cai-dinal area of two examples. The deltidial plates have not united in either sjiecimeu, but have attained a more adv.anced development in fig. 2 than in fig. 3. Fig. 4. Enlargement of the external laraellose suvfai:e ; showing the minute pustules on the radial stria- tions. Niagara group. Lockport, N. Y. Spirifer karicostus, Coiirad. Fig. 5. A brachial view of a specimen of ordinary size. Fig. 6. An enlai'geiuent of the surface of the same specimen ; .showing the inequidistant lamellae. Corniferous limestone. Central Kew Ym-k. Spirifer perlamellosus, Hall. Fig. 7. A normal adult shell, retaining the deltidial covering and foramen. Fig. 8. A median longitudinal section of conjoined valves ; showing the dental plates and median septum of the pedicle-valve and the crura of the brachial valve. Fig. 9. -An enlargement of the external surface ; showing the crowded and radially striated lamellae. Fig. 10. An enlargement of the central portion of the cardinal area, bearing a perforated deltidial covering in which the plates .are completely coalesced and extend to the beak of the brachial valve. Fig. 11. A similar enlargement from another specimen, having a shorter deltidial covering. Fig. 12. The interior of a pedicle-valve ; showing the imperforate deltidial covering and the median septum. Fig. 13. An enlargement of the central jiortion of a brachial valve ; showing the crura and the peculiar bilobed form of the cardinal process lying at the base of the socket-walls. Lower Helderberg group. The Helderhergs, N. Y. Spirifer raricostus, Conrad. Fig. 14. An enlargement of the central portion of the cardinal area ; showing its transverse striation and the incipient deltidial plates. Corniferous limestone. Albany county, N. Y. Fig. 15. An oblique view of the pedicle-valve ; showing the median septum. Corniferous limestone. Western New York. Fi". 16. The interior of a pedicle-valve of a small individual ; showing the teeth and low septum. Fi". 17. An internal cast of a pedicle-valve ; showing the filling of the rostral cavity, the position of the median septum and the impression of the muscular scars. Schoharie grit. Albany county, N. Y. PLATE XXXV— Cimtiimed. Spibifek consobrinus, (I'Oibigiiy. See Plate 34. Fig. 18. The interior of an imperfect pedicle-valve ; showing- the median septum, which appears as a h)w riiige in the bottom of the valve. Hamilton group. Western New Tork. Genus SPIRIFERINA, d'Orbigny. Page .51. Spiriferina transversa, McChesney. Fig. 19. An entire specimen ; showing the general form and proportions, and the lainellose exterior. Fig. 20. The interior of a portion of the pedicle valve ; showing the median septum. Chester limestone. Bmzard.t' Rooat, Alabama. Fig. 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 cardinal process, dental sockets and low median ridge. X2. Carboniferous limestone. Itaituba, Brazil. (Figs. 23-2.') are fi'om specimens figured by Derby, Bulletin of the Cornell University, vol. i, i)l. ii, fig. 6 ; pi. iii, fig. 12 ; pi. v, fig. 4. 1874.) Spiriferina subelliptica. McChesney. Fig. 21. The interior of a portion of the pedicle-valve; showing median septum and musculai' scars. Fig. 22. The interior of a portion of the brachial valve ; showing the articulating apjjaratus, elevated mus- cular ridges and low median I'idge. X 2. Keokuk group. New Prmiidenee, Indiana. 'Spiriferina spinosa, Norwood miil Pratlt'ii. Figs. 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. Fig. 23. An enl.argement of the external surface ; showing the bases of the spinules and the punctie of the shell. Chester limestone. CheMet; llHiiois. ifj Hi ^ 'i; lii: 11 D IP u iLj ^ Palffionl.N.YVolIV.Ptii Spirifendee^ GeiicMir lIliiKl fill ions Plate >5T7, 23 -^1 ""'*% 26 22 ) c 28 D S R-P w.itfifcid .^.-; Phil.Ast hih. PLATE XXXVI. (Figures 1-30 by K. 1'. WiHTi'IEi.D.) Legem! (except tij;iire 80) : I). Deltiilial plates. j. Cardinal process. A. Dellhyrinm. 1). Dental .sockets, t. Teeth. c. Socket-walls. (1. Dental lamellie. a. Adductor scai-s. y. Rostral cavity. d. Diductor scars. s. Median septum. v. Vascular sinuses. Genus SPIRIFER, Sowerby. Si'iKiFER CRisrus, Hisiiigcr. Fig. 1. The exterior of a normal adult. X 2. Fig-. 2. An enlargement of the umbonal region ; showing the undefined cardinal area and iticipiciit . An enlargement of a portion of the interior of the brachial valve; showing the ar-ticulating apparatus and cardinal proce.ss. Fig. 6. An enlargement of the external surface ; showing the closely crowstance. Bnrlington limestone. BwrlingUni, Iowa. Spirifek lateralis. Hall. See Plate 32. Fi". 19. An enlargement of the caidinal area, showing features similar to tlie pre(-e(iing. Warsaw group. Cli/ttm, Illinois. Spirifer Williamsi, sp. IIOV. Fio-s. 20-22. Views of an enlarged example ; showing the low, coai'.se and i^parfe plication of the median fold and sinns. Chemung group. Allegany county, N. Y. SrIRIFER CaNANDAICU^, .sj). IIOV. Figs. 23, 24. Two views of a somewhat distorted individual ; showing the low, roniuled hiteral plications and narrow umbo. Fig. 25. An enlargement of the surface ; showing the closely crowded concentric rows of fine grannies or spine-bases. X u. Hamilton shales. Canandaigua Lake, N. T. Spirifer Hungerfordi, Hall. Fio-a. 26, 27. Dorsal and profile views of a specimen with elongate outline and short hinge. Fig. 28. Anterior view of the same individual ; showing the ilevelopment of the median fold and sinus. Fig. 29. A shell with an extended hinge-line and short longitudinal axis; presenting the extreme of varia- tion in this respect. Fig. 30. The central jiortion of the interior of a pedicle-valve ; showing the teeth, dental lamellie and mus- cular impressions. X 2. Upper Devonian. Rochford, Iowa. Spirifer plenus, Hall. See Geol. Rept. of Iowa, p. 603, pi. xiii. 1858. Fig. 32. An eidargement of a poi'tion of the inner surface of the shell ; showing the puncta. X 4. Fig. 38. A portion of the external surface near the anterioi' margin. X 6. Burlington limestone. Burlington, Iowa. 113 Ili^(S31III©IP ®IS^ Palseonl NY Vol IV Pt 11 = Vol VIII. si'iini i;iiii).v. Cm'Tutu 1 11 ii>>triilii*'ii' RF- Whitfield del Phil.Astliiii. PLATE XXXVIII. (Figs, 1-8, 11-13, 16-19 by U. P. Wihtfiei.d; 9, 10, 14 by G. B. SisirsoN ) Genus SPIKIFEK, Sowerby. Page 1. Spiriker modestus, Hall. Fii'. 1. A silii'itieii example ; .'showing the usual condition of the exterior, ami the absence of uuy defined cardinal area. X '2. Fi"'. 3. The interior of a poi'tion of the pedicle-valve ; showing- the form of the nmscular area. Lower Helderberg group. Cumberland, Maryland. Spirifer lineatus, Martin. Figs. 2, 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 gi-owth-lines. Fig. 8. An enlargement of the cardinal area of the specimen represented in tig. 4 ; showing the incipient development of the deltidial plates and limitation of the cardinal area. Coal Measures. Imoa. . Spirifer Maia, Billings. Figs. 5, 6. Two individuals, showing .slight variations in length of hinge and marginal outline. Corniferous limestone. Near Cvluiiibus, Ohio. Spirifer fimbriatus, Ci)nracl. See plate 36. Fig. 9. An enlargement of a portion of tlie exterior ; showing the long, medially gi'ooved and divided surface-spines, with their lateral spinules. X 3. Fig. 10. A thin section of these compound spines ; showing their interior tilling and the lateral spinules. X 3. Hamilton shales. Caiiandaigm Lake, N. Y. Spirifer l^vis, Hall. Fig. 11. A cardinal view of the pedicle-valve ; showing the completed deltidial covering. Fig. 12. Kxterior of a pedicle-valve; showing faint lateral undulations. Fig. 13. An internal cast of the pedicle-valve ; showing the impi'ession of the muscular area and ovarian mai'kings. Portage group. Ithaca, N. T. Spirifer iiirtus. Wi;ile uinl Wliitticld. Fig. 14. An enlargement of the surface ; showing the concentric rows of spine-bases, each of which retains the i-emnant of the median partition dividing it into two chambers. X 5. Kinderhook group. Illinais. Spirifer divaricatus, Hall. Figs. 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 Wortiicn). Fig. 18. The peilicle-valve of a large individual. Fig. 19. Internal cast of a pedicle-valve ; showing the vertical striation of the cardinal area, the impression of the muscular area and the ovarian markings. Keokuk gi'oup. Crawfordsville, Indiana. m m ^ (s mn m 3^ m m ^ Palceont.N Y Vol lA'^Pt ii= Vol Vin Sl'lm I KHID.V. (l,-l\lates. a'. Posterior ailductoi's. 8. Me Kp _hp ^^^^ '•^-->j '^ -,-<^ ^ E Emmons del PLATE Xmi. (Figures l-i:i by F. B. Meek; 14, 15, lS-30 by R. P. Wiin tiei.d; !«, 17 l>y E. Emmons.) Genus MKK18TKLLA, Hall. riige 73. Meristella arcuata, Hall. See Plate 44. Figs. 1, 2. Two views of a normal shell ; showing form ami 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. T. Meristella sella, 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 princeps, 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 liriguiform extension in front. Figs. 12, 13. Dorsal and vential views, presenting the usual characters of an adult specimen. Lower Helderberg group. Schoharie, N. Y. Meristella subquadr.\ta, Hall. Figs. 14, 15. Dorsal and profile views of a typical specimen. Lower Helderberg group. Schoharie, N. Y. Meristella Walcotti, sp. iiov. See Plate 44. Figs. 16, 17. Dorsal and profile views of a rotund and rather elongate example. Oriskany sandstone. Cayuga, Ontario. Meristella nasuta, Couratl. See Plate 44. Fig. 18. Ventral view of a shell of median size. Corniferous limestone. Ene 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 sorface strise. Corniferous limestone. Williamsville, N. Y. PLATE XLUI— Continueil. Meristella Haskinsi, Hall. See Plate 44. FigB. 23, 24. Di'i'sal ami jji-ofile views of the usual form of the species. Hamilton shales. Moscow, N. Y. Meristella Baukisi, Ilali. See Plate 44. Figs. 25, 26. Ventral and dorsal views of different shells, giving the external characters. Limestone of the Marcellus shales. Stafford, N. Y. Merlstella kostkata, Hall. Fig-8. 27, 28. Dorsal ami profile views, showing the usual form and size of the species. Tully limestone. Ovid, N. Y. Meristella Meta, Hall. Figs. 29, 30. Dorsal and ventral views of an adult specimen. Hamilton group. Delphi, N. Y. Palaeont N Y. Vol, nrPtu = Vol VIII- 113 m^(BSia®i? ©im^ MKHISTIDV. (T^'inTir ! lliisti-.itioiis Plate XL III RT. Whitfield del Phii.Asiiitti. PLATE XLIV. (Figures 1-12, 15-19, 23, 24, 27, 28, 31, 32 by E. Emmons; 13, U, 20-22, 25, 26, 29, 30 by R. P. Whitfield.) Legend : ilp. Deltidial plates. r. Didiictor sears. p. Pedicle-cavity. a. Anterior adductors, d. Teeth. a'. Posterior adductors. Genus MERISTELLA, Hall. Page 73. MeRISTELLA BELLA, Hall. See Plate 43. Fig. 1. The intenor of a pedicle-valve ; showing the teeth, the deeply excavated muscular area and the testaceous thickening which fills the pedicle-cavity except along the median line. Fig. 2. The interior of the lirachial valve ; showing the suliquadrate outline of the hinge-plate, its post-lateral expansions and the ante-lateral position of the crural bases. X 3. Fig. 3. The hinge-plate viewed in profile from the anterior margin of the brachial valve ; showing its con- cave surface, the elevation of the crural bases and the median supporting septum. Lower Helderberg group. The Helderbergs, N. Y. MkRLSTELLA LyEVIS, Hill]. See Plate 43. Fig. 4. The hinge-plate ; showing its subtriangular form, median concavity and supporting septum. X 3. Lower Helderberg group. Albany county, N. Y. Meristella arcuata, Hall. See Plate 43. Fig. 5. The hinge-plate viewed from in front ; showing the dental sockets and socket-walls, elevation of the crural bases and the median septum. Lower Helderberg group. Schoharie, N. Y. Meristella Walcotti, sp. iiov. See Plate 43. Fig. 6. The spirals and loop, naturally preserved by incrustation of silica, and exposed by the removal of the pedicle-valve. The specimen is viewed from the anterior margin, and in the cavity be- tween the cones is seen the looji with its scissors-shaped branches. Fig. 7. The same specimen viewed from the posterior margin, and showing the position of the branches of the loop with reference to the ribbon of the spiral cones. Fig. 8. A similar preparation, to which a portion of the internal cast of the valves adheres. The speci- men 13 viewed from the dorsal side and shows the form of the spiral cones and the length of the median septum. Fig. 9. An internal longitudinal view ; showing the 'position and form of the loop and one of the .si)iral cones. Partially restored. Fig. 10. A naturally incrusted brachidium viewed from the dorsal side, and showing the prominence of the primary lamellte of the cones. Fig. 11. A similar specimen ; showing the spiral cones on tlie ventral side. Fig. 23. A view of the brachidium from the ventral side, a portion of the cones being omitted to show the primary lamellae and loop. Restored. Fig. 32. The hinge-plate. Drawn from a gutta-percha cast. Oriskany sandstone. Cayuga, Ontario. Meristella lata, Hall. Fig. 12. An internal cast of the pedicle-valve ; showing the filling of the pedicle-cavity and of the deep muscular impression. Oriskany sandstone. Albany county, N. Y. PLATE XLIV— Continued. Meristella nasuta, Conrad. See Pliile 43. Fig. 13. An internal cast of a peiiicle-valve ; showing the position of the teeth and the deep muscular im- pressions. Fig. 14. An internal cast of a small and very elongate pedicle-valve ; an nnusual variation in form. Schoharie grit. Albany county, N. Y. Fig. 19. A pedicle-valve retaining the lirachidium in a silicihed and incrusted condition ; showing the form of the cones and retaining in position the median septum of the brachial valve. Corniferous limestone. IVillia^nsviUe, N. Y. Fig. 20. A similar specimen, the spirals being unincrusted and exjiosed by weathering. Fig. 21. The interior of an incomplete pedicle-valve ; showing dental plates and muscular impressions. Fig. 22. The interior of a brachial valve ; showing the subtriangular, medially concave hinge-plate, dental sockets, median septum and elongate adductor muscular area. Fig. 24. The hinge plate enlarged ; showing the median depiession, crural bases and supporting septum. X 3. Fig. 25. Cardinal view of an internal cast of conjoined valves ; showing the impressions of the muscular scars, teeth and dental lamell:e,'sookets and median sejilum. Corniferous limestone. Western New York. Fig. 26. An internal ca.st of the brachial valve. Schoharie grit. Schoharie, N. Y. Meristella lenta, Hall. Fig. 15. An internal cast of Ibe pedicle-vaUe ; shuwing the sliong muscular scars and the generally de- pressed surface. X 2. Fig. 16. A preparation, showing the form of the spiral cones resting in the pedicle-valve, with the median dorsal septum in position. Fig. 17. An internal cast of the brachial valve, showing its convexity and the position of the median sep- tum. A portion of the tilling of the pedicle-cavity of the opposite valve is also exposed. X 2. Fig. 18. A longitudinal internal view, showing the position and form of the loop and one of the spiral cones. Restored. Oriskany sandstone. Be Cewville, Ontariu. Meristella Barrisi, Hall. See Plate 43. Figs. 27, 28. Two views of a preparation, showing the tbrm of one of the spiral cones. Fig. 29. An internal cast of conjoined valves ; showing the jiosilion of the median septum and dental laraells. Fig. 30. An internal cast of the pedicle-valve. Limestone of the Marcellus shale. Stafford, N. Y. Meristella Haskinsi, Hall. See Plate 43. Fig. 31. The interior of a pedicle-valve retaining the deltidial plates, and showing the teeth and muscular scars. Hamilton group. Canandaigua Lake, iV. Y. mm^'sm^miF^m^ Palaponl, N Y.Vol IVPt ii = VqI.VIII. MKKisrin.v. ('■.•ui'i-ic lllu^h .llMITlS PI ate XL IV EEramoiis dc Phil^AstliUi. PLATE XLV. (Figures 1-3, li-12, 16, 18-24, se-'-'S, by K. P. WunTiELD; 4, 5, 13-15, '2b, 211, 30 by E. Emmons; 17 by G. li. Simpson.) Genus ATHYRIS, McCoy. I'ago S3. Atiiykis vitt.vta, Ilall. Figs. 1-3. Dorsal, proiile and antiMior marfjinal viows of a normal inilividual ; showing its comparatively short traiisvei'se diameter and the devL'lopment of tht; median fold and sinus. Fig. 4. The hinge-plate as viewed from above ; showing the ti'ilobation of the anterior margin, the deep depression of the median portion, the eoalescence of the lateral portions with the socket- walls, and the large, nnobstrncted vi.sceral foramen. The lateral lobes are the bases of the ci-nra and are incorrectly represented as entire at their outer extremities. X 3. (c.) Fig. 5. The interior of the cardinal poi'tion of conjoined valves, the brachial valve being above. This view shows the elevation of the anterior 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 jirimary lamelLo; of which a portion is shown. X 3. (c.) Hamilton group. Falls of the Ohio. Atiivuis Cora, Hiill. 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 meilian sinus on each valve. Hamilton group. Dvlyhi, N. T. Athyris spirlferoides, Eaton. Fig. 11. Dorsal view of a large and senile individual, having the surface laraellas 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 sJiales of Wester7i New York. Fig. 13. A prepai'ation of the brachidium, one of the spiral cones being I'emoved to expose the structure of the loop. This figure shows the depressed ventral surface of the cones, the mode of attach- ment of the ci-ura to the primary lamelliB, the anterior position of the loop, its broad lateral bi-anches and saddle, the long stem, and the width and extent of the accessory lamella;. X 2. (c.) Hamilton group. Alpena, Michigan. Fig. 14. An enlargement of the hinge-plate ; showing its subquailrate-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 submar- 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 innei' wall and base of the dental sockets. In the background are seen the posterior elevation of the socket-walls, the visceral foramen 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 lamell.'E are few and distant. Hamilton group. Western New York. Fig. 17. The interior of a brachial valve ; showing the structure of the ai'ticulating apparatus and the elongate scar of the adductor muscles. Hamilton gi-oup. Falls of the Ohio. PLATE XLV— Continued. Figs. 18, 19. Dorsal and canlinal views of a narrow and rather rotund individual. Fig-. 19 shows the mar- ginal inflexion on the cardinal slopes of the 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. Varioiis localities in the snft shaJes of Western New Turk. Fig. 22. A dorsal view of an internal cast of conjoined valves, showing the impi'ession of the hinge-plate, the filling of the visceral foramen, the muscular scars and vascular markings, and also the cast of the rostral cavil}' of the pedicle-valve. Hamilton group. Hardy euunty, Virgi7iia. Fig. 23. A'ventral view of a jireparation of the brachidiuin ; showing the form of the spirals, the crui-a and their attachment to the primary lamellfe, and the accessory laraelliB. Fig. 24. An internal cast of the pedicle-valve, slightly broken at the umbo ; showing the adductor and diductor impressions, and the vascular sinuses. Fig. 25. The exterior of a transverse, coarsely lamellose individual. Hamilton group. Varioits localities in tlie shales of Western New York. Athykis Angelica, Hall. Fig. 26. The exterior of a bi'achial valve. Fig. 27. The exterior of a pedicIe--\-alve. 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-jilate ; showing the straight anterior edge, the ci-ural plates, visceral foramen, and the elevation of the posterior portion of the surface. X 3. Fig. 30. A profile view of an old and gibbous shell, with a few strong growth-lines. Chemung group. Belfast, N. Y. Athyridae. Palaeonl.N r.Vol.IVPt n- Vol.vm, I'lMvci-ir Illiistr.itloiis Plate XLV RP.Whitfield del Phil.Asiiith. PLATE XLVI. (Figuies 1-5 l>y R. P. WuiTPlELD; 6, 10, 18, '2i-21 l>y G. II. Simi'Son; 7-3, 11-21, 2S-'J8 by li. Emmons.) Legend : p. Pilling'- of pedicle-cavity. i a. Anterior adductors, t. Teeth. a'. Posterior adductoi'S. d. Dent.al lamella:. vc. Cast of visceral foramen, cs. t'ai ilinal margin. lip. Cast of hinge-plate, r. Diduetor scai-s. Genus ATHYRIS, McCoy. Page 83. See Plate 45. Athyris polita, Hall. Fiff. 1. A ventral view of an iiitei-nal cast ; showing the filling of the rostral cavity and the muscular impressions. Fig. 2. Dorsal view of the same specimen. Figs. 3-5. Profile, dorsal and ventral views of a specimen retaining the external surface. Chemung group. Stnihen ccmnty, N. Y. This species has more the contour of shells which have been placed under the subgenus Semi- NDLA. than of the ti-ue Athykis. Should its surface prove to be devoid of free lamellse, it would naturally fall into that group. Athyris densa, .sp. nov. 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. ColesimrgJi, 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 lidge. 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. Washington, county, Indiana. Figs. 9, lU. 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. CoUsburgh, 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. Colesburgk, Kentucky. Athyri.s Hannibalensis. Swallow. Fig. 13. A dorsal view of the exterior of conjoined valves ; showing the highly lamellose surface. Fig. 14. The exterior of a pedicle-valve ; showing the b.ases of the free lamells, and the low median sinus. Fig. 15. The interior of a pedicle-valve ; showing the chai'acter of the muscular area. Choteau limestone. Louisiana, Missouri. Athybis lamellosa, L6veill6. 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 lamella;. Fig. 17. The opposite side of the same specimen ; showing the peculiar form and division of the adductor scars, and a portion of one of the concentrically striated free lamella. Waverly group. Sciotoville, OJiio. PLATE XLVI— Continued. Fig. 18. The exterior of a pedicle- valve ; showing' the noi'mal marginal outline of the species. Fig. 19. The exterior of a large brachial valve with few and distant lamellie and unusually extended hinge-line. The tirst 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 ex)iansion of the submarginal lamella. Keokuk group. Crawfm-dmntle, Indiana. Fig. 20. The central cardinal portion of an internal cast of conjoined valves, enlarged ; showing the posi- tion of the teeth, dental plates and hiiige-j)late, the filling of the pedicle-cavity and viscei'al foramen, the latter being tj-aversed for its entire length by a median gi-oove, representing a faint median ri-.s. Figs. 7, 8. Dorsal and protile views of the ojiginal sperimen. Lower Heldei-berg group. Square Lake, Maine. Trematospira multistriata. Hall. Figs. 9, 10. Dorsal and ventral views of the exierior of a normal example. Fig. II. A prepai'ation showing one of the spiral cones, the form and position of the loop and the mode of attachment .!«f;eiddii PMlAsthth. PLATE L. (Figures 1-5 copies; 6, 8, I2-U, 28-31, 41-48. 51, 63 by E. Emmons; 7, ii-U, IR, 17, 20. 23. 24, 32-35 by G. B. Simpson; 15, 1«, 19 by J M. Clarke; 21 by F. 1$. Meek; 23, 25, 36-4U, 4!), 60 by R. P. Whitfield ) Legend ; t. Teeth. b. Dental sockets. .'f Median eeptum (pedicle-valve), d. Dental [dates. c. Crura. a'. Median septum (brachial valve), hp. Hinge-plate. Genus RETZIA, King. I'.ige lOi. Retzia Adrikni, do Venieiiil. Figs. 1, 2. Doi'sal and ventral views of a typical sjiecimen ; showing ihe characters of the exterior. Fig. 3. A doi-sal view of a smaller example, from which a portion cjf the brachial valve has been removed, exposing the median septum and a portion of one of the si>iral C(mes. Fig. 4. An enlarged view of a shell which has Ijeen ti-ansversely sectioned just in front of the nmbones; showing the hinge-plate, dental sockets and median septum. Fig. 5. 'J'he interior of a portion of the bi-achial v.alve ; showing Ihe hinge-plate and median septum. The above figures are cojiied from QiuLERT, Annates Sci. Geol., t. xix, No. 1. Ib86. Fig. (i. 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 ami the concave coalesced deltidial plates. X 2. Lower Devonian. DeparUiiient cle la iSa)'the, France. Genus PTYCHOSPIRA, gen. nov. Page 112. Ptychospira feeita, von Buch. Fig. 10. A profile view of an average individual ; showing the coarse plication, and the exten.sion of the anterior margin. X 2. Fig. 11. A dorsal view of the same specimen ; showing the coalesced deltidial plates. X 2. Middle Devonian. Eifel, Germany PxYCHOsriRA LONGiuo.STRis, Kaj.ser. Fig. 12. A dorsal view of a specimen ; showing the narrow and elevated beak of the pedicle-valve. Middle Devonian. Eifel, Germany. PxYCHOsriRA (cf.) sexi'Licata, White iiiid Whitfield. Figs. 13, 14. Dorsal and ventral views of a specimen, probably referable to this species. Burlington limestone. Biirthigton, lima. Subgenus HOM(Ji:OSPIRA, s.-gkn. nov. Pase 112. HOMCEOSPIRA EVAX, Htlii. Fig. 15. A dorsal view of the youngest shell observed. In this stage of growth the beak of the pedicle- valve is ei-ect and the deltidial plates not developed ; the surface of the valves is smooth and evidence of plications is visible only outside of the second concen)i-ic growth-line. X 25. Figs. 16, 17. Profile and dorsal views of ns Plate LI. QB. Simpson del Phii.As tilth. PLATE LII. (Figures 1-15 by G. B. Simpson; 16-19 by E. EMMONS; 20-36 copies.) Genus CLINTONELLA. gen. nov. Vane 159. Clintonella vagabunda, s|). nov. Fig. 1. A dorsal view of an internal cast i-etaining the shell on the umbo of the pe4-28, 32-35, 39 by li. P. Whitfield; 43, 44, 60, 62 by F. B. Meek 1 Genus ATRYPINA, gen. no v. Page lai. Atrypina disparilis, HiiU. Figs. 1-3. Ventral, protile and dor.sal v'ibw.'* of an average inaluie exani|ple; showing the plano-convex contour, sjianse plication and concentric surface markings. X 2. Fig. 4. A dorsal view of a very young individual; showing the deltidial plates beneath the erect beak, the deep median sinus of the brachial valve and its low plications. X 5. Niagara' group. Waldron, Indiana. Atrypina imbricata, Hall, Fig. .n. The interior of a pedicle-valve ; showing the concave delti. Lower Helderberg grcnip. Near darksville, N. Y. Genus CCELOSPIRA, Halt,. l>;ii,'e 134. CfELOSPIRA PLANOCONVEXA, H;ill. See Plato :>2. Figs. 11-13. Ventral, dorsal and protile views of a specimen, natural size ; showing the contour and surface characters of the shell. Fig. 14. The iutei'ior of a brachial valve; showing the form of the cardinal process and the thickened median i-iiige. X 2. Fig. 15. A still further enlargement of a poition of the same valve, to show Ihe grooved lobes of the canl- inal proce.=!s. X .^. Fig. 16. The interior of an incompl.-'te brachial valve : i^howing cardinal process, dental sockets, and the muscular depressions on either side of the thickened median I'idge ; etdai'ged. Clinton groii]>. Hamilton, (hitario. Genus ATRYPINA, gen. nov. ViViK 101. Atrypina Clintoni, sp. nov. Fig. 7. The interior of an incomplete brailiial valve ; shciwing the bilobed hinge-plate and the median muscular i-idge. X t>- Fig. 17. A dorsal view of a specimen ; showing the internal cast of the brachial valve and the teeth and rostral cavity of the jiedicle-valve. X 2. Fig. 18. An internal cast of the pedicle-valve ; showing the ailductor and diductor muscular scars. X 2. Fig. ]!). The exterior of a jteilicle- valve. X 2. Clinton group. Drift of loestera New York. Genus CCELOSPIRA, Hall. Page 134 C(ELOSpira concaa'a. Hall. Fig. 20. The exterior of a pedicle-valve. X 2. Fig. 21. The exterior of a brachial valve ; .showing its concavity and the posterioi- p(n-tion of the cardinal process. X 2. Fig. 22. The interior of the brachial valve ; showing the character of the cardinal process and socket-walls, and the median thickening between the muscular impressions. X 3. Fig. .23. The interior of an incomplete pedicle-valve ; .showing the open delthyrinm, tlie teeth and muscu- l.ar ini|n'essions. X 3. Lower Helderbei-g gronji (Shaly limestone). Near ClarkxmUe, N. T. PLATE LUI— Continued. C(ELOSPiRA Camilla, H;ill. Figs. 24-26. Dorsal, iirotile ami ventral views of a typical specimen; showing' the contour and surface char- acters. X 2. Fig. 27. The interior of the bra<-hial valve ; showing; the elevated anil somewhat recurveil hinge-plate. X 4. Pig. 28. The interior of ii pedicle valve; showing the open delthyriutn. the teeth anil muscular impres- sions. X 4. Corniferous limestone. Caledonia, N. ¥. Fig. 29. The interior of a pedicle-valve ; showing characters similar to tliose of the preceding figure. X 2. Fig. 30. The exterior of a pedicle-valve. X 2. Fig. 31. The interior of a brachial valve ; showing the hinge-plate and median ridge. X 3. Corniferous limestone. Lc Roy, N. Y. CffiLOSPIRA ACUTIPLICATA, Coiliud. Figs. 32-3."i. Doi'sal, profile, ventral and frontal views of the exteiior of a typical specimen ; .showing the contour, coarse, sharp plication and concentric lineation of the v.alves (/Orniferous limestone. Jamesville, N. Y. Fig. 3ti. The interioi' of a portion of the bi-achial valve; showing the i-ccurved hinge-plate, ileej) ilental sockets and median I'idge. X 3- Fig. 37. The exterior of a pedicle-valve slightly imperfect about the raaigins. X 2. Fig. 38. The interior of the same specimen ; showing the open delthyrium and teeth. X 2. Corniferous limestone. JVate)-Io(i, N. Y. Fig. 39. The interior of a brachial valve with faint lateral plications ; showing the hinge-plate, dental sockets and median ridge. Corniferous limestone. Sangerfield, N. Y. Genus LEPTOCGELIA, Hall. Page 13ii. Leptoc(ELia flabellites, Hall. Figs. 40-42. Dorsal, ventral and profile views of an average example ; showing the contour and sui'face characters. Fig. 43. The interior of a brachial valve ; showing the structui'e of the hinge-plate, dental sockets and muscular area. Fig. 44. A profile of a large shell ; showing the plano-convex contour. Fig. 45. The interior of a brachial valve, somewhat imperfect about the margins ; showing a slight varia- tion of the characters as represented in tig. 43. Fig. 46. The cardinal region of another brachial valve, enlarged ; showing the excavation of the cardinal process im either side of a median ridge, and the projection of the crural lobes. X 2. Fig. 53. The interior of a pedicle-valve ; showing the open delthyrium, teeth, adductoi' and diductor scars. Oriskany sandstone. Cumberland, Maryland. LEPTOCffiLIA FIMBRIATA, Htlll. Fig. 47. Dorsal view of the posterior poi-fion of the shell; showing the fimbria of spinules or testaceous jirocesses extending fi-om between the cardinal margins. X 3. Fig. 48. A profile of a brachial valve; .showing the elevation of the cardinal process and crura. X 3. Fig. 49. Caidinal view of a brachial valve ; showing the elevation of the cardinal process, socket-walls and crura, and the foreshortened cardinal spinides. Fig. 50. Dorsal view of conjoined valves ; showing the exterior characters and the cardinal spinules. X 3. Fig. 51. The interior of a brachial valve; showing the structure of the articulating apparatus, the char- acter of the muscular area, and the mai-ginal spinules which are inserted upon this valve. X 2. Fig. 52. The interior of a pedicle-valve ; showing the foramen, teeth and muscular aiea. X 2. Figs. 54, 55. Interiors of pedicle-valves ; showing some variation in the retention of the .structural features. X 2. Oriskany sandstime. Oumberland, Maryland. 33 Hi ^ © IS H ® IP © lEJ ^:!^ Palasonl.N Y.Vol JVPt ii- Vol Vin CCKI.dSlMUl D.V. ( 'i-ncric I llusti;iti(>ii> Plate L III y"^ W % 6 1 s>l/^ %m K ^ I 1 ) .V. ("u'lieiii- Illustrations Plate LV R,P. Whitfield del. Prdl^AstUth. PLATE LVI. (Figures 1-13, 16-2S, 28-34, 3ii,37, « by G. B. Simpson; 11, 15, H~-i7 by U. P. Whiti'Ield; 35, 38 by C. E. BEECHER; 39-44 copies.) Genus RHYNCHONELLA, Fisciiek de Waldheim. Page 177. Rhynchonella loxia, Fi.-^cher tie Wtildlieiiii. Figs. 1-5. Dorsal, ventral, profile, frontal and cardinal views of a normal mature individual, retaining the smooth external surface, and showing' the contour, acuminate median fold and sparse lateral ]ilication. Vtg. 6. Cardinal view of an internal cast ; showing the cavity of the dental plales and median sejitum. This is the type of the genus Rhynchonella. Upper Jurassic. Ckaraschowa, Runsia. Genus PROTORHYNCHA, oen. nov. Page ISO. Protokhyncha ^QUIRADIATA, Ililll. Fig. 7. An internal cast of the brachial valve ; showing the length of the median .septum. X 2. Fig. 8. The cardinal portion of the brachial valve, enlarged ; showing a clearly defined cardinal ,'irea, oblique dental sockets, the broad, rather ill-defined hinge-plate, with a median cavity whose lateral walls are continuous with the median septum. X 3. Fig. 9. An internal cast of a larger i)edicle-valve ; showing a well defined median sinus and a very re- stricted muscular scar in the umlional region. X 2. Clinton group. New Hartford, N. T. Genus ORTHORHYNCHULA, oen. nov. Page 181. Orthokhynchula Linneyi. Nettelrotli. Figs. 10-12. Dorsal, pi-ofile and ventral views of the exterior of an average example; showing contour and character of plication. Fig. 13. The central portion of the cardinal i-egion, enlai-geones .and the median sinus on the brachial valve. X t). (After Beecher and Clarke.) Niagara group. Waldron, Indiana. Figs. 36, 37. Ventral and dorsal views of an internal cast of conjoined valves ; showing, in figure 3G, the impression of the pedicle muscle, the diductor and adductor scars Ijouniled by divergent ridges, and, in figure 37, the cast of the deltidial cavity and the extent of the medijin .septum. Niagara dolomites. Near Milwaukee, Wiscon.mi. Fig. 38. The cardiual region of an adult specimen, enlarged ; showing the uuusual size of the deltiilial plates, their outward flexion along the median suture, the apical and enci'oaching position of the foramen. X 5. (After Beecher and Clabkij:.) Niagara group. TValdro7i, Indiana. Rhynchotreta cuneata, Daliutiii. Figs. 39, 40. Profile and dorsal views of a noimal adult. (After David.son.) Wenlock limestone. Dudley, England. Genus STENOSCHISMA, Conrad. Page 1S7. StENOSCHISMA FORMOSA, Hall. Figs. 41-43. Dorsal, profile and ventral views of the exlei-ior. Fig. 44. Frontal view of another examjile. Fig. 45. Enlargement of the hinge-plate ; showing its deep median division, minute cardinal pi'ocess, flat crural lobes and concave (uura. X 4. Lower Helderlierg group (See Vol. Ill, p. 23G, pi. xxxv). Alliany county. N. T. m m ^ (s m'3. m IF m m £^ PaleeontN YVol.IVPt 11 = Vol.VIIL i;iiYN( ii(iNi:i i.iiiA. ( U'lUMir I lliir^ll .itimis Plate LVI i> ^/, 1 t'"- mm i^ ,^. 'im- ■■ ^'1^ f^. •m. -'!* 32 (Jh 0- % ^^Sl?* G,B Simpson del. rhii.Ast-litk. PLATE LVII. (Figures 1-50 by R. P. \VHirriEi.D; 51-54 by E. Emmons.) Genus CAMAROTCECHIA. gen. no v. I'aRC 1S9. Camarotcechta Tethys, Billin_2;.s. Figs. 1, 2, Cardinal and profile views of a ntther large shell. Coriiifei'ous limestone. Province of Ontario. Camarot(echia Billinqsi, Hall. Fiu;. 3. Porsal view of an internal cast ; showing the position of the median septum. Corniferous limestone. Westei-n New York. Camarot(echia Carolina, Hall. Fig-s. 4, 5. Dorsal and cardinal views of a partially exfoliated specimen. Fig. 6. Front view of a moi'e gibbous shell. Corniferous limestone. iSandiisky, 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. Dor.sal, ventral, cardinal, profile and frontal views of a large and typical example. Hamilton group. Western New York. CAMAROTOiCHIA CONGRE(iATA, Hall. Figs. 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 jiedicle-valve ; showing a large diductor impression. Fig. 22. A similar cast of the interior with the muscular area more restricted. Fig. 23. An internal cast of a brachial valve ; showing the length of the median septum, the tilling 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 outei' socket-walls. Figs. 26, 27. The same parts drawn from gutta jiercha 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. Various 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 plications on the median fold. Chemung gi'oup. Central a7id western New Ym-k. Camarotcechia Stevensi (^ Rhynchonella Stephani), Hall. Fig. 33. An internal cast of the pedicle-valve. Pigs. 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 septimi. Chemung group. Bradford county. Pennsylvania. Pr-ATK LVn— Continued. CaMAROTCECHIA (?) DUPLICATA, Hall. Fig-s. 36-38. Ventral, frontal and dorsal views of the original example ; showing the single plication and sulcus on siiuis ami told respectively, and the obscure and sparse lateral plication. Fii>-. 3y. The interior of a brachial valve, ilrawn from a gutta-percha cast ; showing the hinge-plate, crura, median septum and muscular impressions, anharie cnunty, N. Y. Figs. 3-5. Frontal, cardinal and ventral views of a larg-er specimen. Limestone of the Mai'celhis shales. Avon, N. Y. LlOUHYNCIIUS DUBIUS, Hall. Figa. 6, 7. Ventral and dorsal views of a typical specimen. Marcellus shales. Locality f LxORHYiNCHUS MULTICOSTA, Hall. Fig. 8. The exterior of a pedicle-valve of an elongate specimen, the regulai- growth of which haa been interrupted in the umbonal region. Fig. 9. The brachial valve of a more orbicular and typical shell. Fig. 10. A cardinal view ; showing the convexity of the Ivalves. Hamilton group. Western New York. IjIORHVNCHI'.S ME.SACOSTALI.S, Hall. Fig. 11. The exterior of the pedicle-valve ; showing the inequal plication of the sinus. Fig. 12. An internal cast of a large brachial valve; showing the position of the median septum, the elon- gate muscular scars and the absence of plications on the latei'al slopes. Chemung group. Tompk'nis county, N. Y. LlORHYNGHUS LaURA, Blllillgb. Figs. 13, 14. Ventral and dorsal 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. LiORHYNCHDS 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 vential views of a normal adult ; showing the obsolescence of plications except upon fold and sinus. Hamilton group. No^ihem Ohio. LlORHYNGHUS QUADRICO.STATUS, 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 bi-achial valve in which the lateral jilications are obsolete. I'LATE LIX— Continueil. LlORHYNCHUS (iLOUULIFOKMLS, VaiUiXCIU. Fig. 23. The exterior of the brachial valve ; .showing its rotundity, the low, faintly plicated fold and smooth convex lateral slopes. Hamilton groiijj. Otsego amnty, N. Y. Fig. 24. The extei-ior of a pedicle-valve with traces of marginal plications on the sinus. Fig. 25. An internal cast of a more orbicidar shell with stronger median plication. Black shale (Genesee shales). Lexington, Indiana. Fig. 26. An internal cast of the bi-achial valve ; showing the extent of the median septum and the form of the adductor scai-s. Fig. 27. Enlargement of the umbonal portion of an intei-nal cast of the brachial valve ; showing the tilling of the dental sockets and spondylium, the cavities left by the removal of the hinge-plate and thickened median septum. Chemung (?) group. Broome county, N. Y. LlORHYNCHUS CASTANEus, Meek. Figs. 28, 29. ProHle and dorsal 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 ROBUSTUS, Sp. IIOV. Figs. 30, 31. Cardinal and ventral views of a very sharply marked internal cast of large size, representing an hitherto undescribed species ; showing the muscular impressions of both valves and the vascular sinuses in the i)edicle-valve radiating from the impression left by an umbonal testace- ous callosity. Chemung group. Steuben county. N. Y. LlORHYNCHUS KeLLOGGI, Hilll. Figs. 32, 33. Dorsal and ventral views of an adult shell with more distinct plication than that represented in figures 19, 20. Hamilton group. Northern Ohio. LlORHYNCHUS LeSLEYI, S[i. IIOV. Figs. 34-36. Dorsal, ventral and profile views of a mature shell ; showing the rathei' obscurely defined fold on the convex Virachial valves, the deep sinus of the pedicle-valve, and the unusually complete plication of the lateral slopes. Upper Devonian. Peniisylvania. LlORHYNCHUS Newbehryi, Hflll aiul Whitlield. Fig. 37. An internal cast of the brachial valve ; showing the large size of the shell, low median fold, and tine plication. Fig. 38. Cardinal view of an incomplete internal cast of both valves. Upper Devonian. Kelloggsinlle, Ohio. 113 IliJS.CgIlIH®Ip (BS)^ Palasont.N Y.VoMYPt-ii= Vol.Vin. |;|IYN( IIOXKI.I.ID.V. ( 'cin'fu lllnslr.ilions Plate L IX R.P, Whitfield del. Phil.Asilitli. PLATE LX. (Figures 1-.!, 6-10, 13-49, SI, 53, 54^by G. B. SIMPSON'; 4, 5, 11, l'2 by K. Emmons; 49, 50, 52, 65 by K. 1'. Whitfield.) SUBGKNUS PUGNAX, S.-QEN. NOV. Page -lOi. PUGNAX ALTUS, ('illvill. Figs. 1-3. Dorsal, profile and frontal views of an average specimen ; sliowing the trihedral form and the character of the plication. Middle Devonian. >So!o7i, Iowa. Figs. 4, 5. Frontal and profile views of an individual with highly elevated median fold. Middle Devonian. Haokbemj Gi-ovc, Iowa. PUGXAX PUOXUS, Mllftill. 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 ; 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 EATONiiFORMis, McChesiiey. Figs. 11, 12. Front and profile views of the original specimen ; showing the str-ong but spar.sely plicated median fold and sinus and the smooth lateral slopes. Coal Measures. Qraysnille, Illinois. PuGNAX Gkosvenoki, Hal!. 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 Hill, Indiana. PuGNAX MUTATU8, Hall. Figs. 18, 19. Doi'sal and profile views of an average example. Fig. 20. The interior of an incomplete pedicle- valve ; showing an open delthyrium, small teeth and dental plates. Fig. 21. A portion of the intei-ior 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, Whitf. Figs. 23, 24. Dorsal and front views of a normal example ; showing the plication about the margins and the elevation of the median fold. Fig. 25. The interior of a poi'tion of the brachial valve ; showing the broadly divided hinge-plate. X 2. Fig. 26. The interior of an incomplete iiedicle-valve ; showing teeth and dental jilates. X 2. St. Lonis group. Pella, Iowa. PuGXAX Svvalloviana, Sluimtlltl. Figs. 27-29. Dorsal, profile and front views ; showing the contour and character of plication. X 2. Fig. 30. Profile view of an internal cast; showing vascular sinuses on the brachial valve. X -'. Figs. 31, 32. Ventral and dorsal views of a smaller shell. X 2. Id all of these the absence of plications over the umbonal regions is a notable featui'e. Upper Coal Measures. Manhattan, Kansas. PLATE LX— Coiitlnued. PuGNAX MissouRiENSis, Sluimurd. Figs. 33, 34. Dorsal and profile views of an average example ; isliowing' llie lineate striatioii of the surface. Choteau limestone. Pike county, Missouri. LlORHYNCHUS (?) BOONENSIS, SllUlllaid. Fig. 35. Cardinal view of the hinge-plate ; showing its median division and the elevation of the crnra. X 3. Choteau limestone. Cooper county, Missouri. PuGNAX GrEENIANUS, Ullicll. Figs. 36-38. Front, profile and dorsal views of an internal cast of an average individual ; showing the smooth lateral slopes and faint plication of fold and sinus. Keokuk group. New Albany, Indiana. Pugnax Uta, Maicoii. Figs. 39-41. Dorsal, 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 explanatus, McCliesiiey. Figs. 43-45. Fi'ont, dorsal and protile views, diawn from a sulphur cast of the original specimen. Kaskaskia limestone. Illinois. Pugnax, sp. ? Figs. 46-48. Protile, front and diir.sal views of an undetermined internal cast. The shell has some points of similarity to the Rhynchonclla IlUnoisensis, Meek and Worthen. Coal Measures. Qraham county, Texas. Genu.s HYPOTHYRIS, King. HrpoTHYRrs venustula, Hall (^Riiynchonella cuboides. Sowerin). Figs. 49, 50, 52. Cardinal, frontal and jirofile views of a typical specimen ; showing the subcuboidal form, low median fold and l)road, deep median sinus. Fig. 51. 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 pedicle-valves ; showing the muscular impression, and some variation in the form of the vascular sinuses. Fig. 55. An internal cast of the pedicle-valve, enlarged to show the system of vasculai- sinuses. X 2. Tully limestone. Ovid, N. Y. 113 m ^ m m.!! m w m m ^ Palffiont.N.Y.Vol IVPtii = Vnl VIII lillYMMONI'.I.MD.V. (..■luTic lllii^ii .lll.Mls PlateLX V//H ^ ^ijii ^ ^ -4 m.- 4 30 rU^ ^, M' 42 P^\ m (S ^ G.B.Simpson del PhilAsiliTli. PLATE LXI. IFiguivs I'd. -.M, a'i, ■>?, M, 3-J, 37, :js l)y G. li. SiMi'SON ; 11, |-2"l)y U. P. Whitkiei.T) ; I:i-1H, 'Jl, 'iJ, 25, 20, 29-31, 33-35 by F B. Mekk ; 21,:i(; by E. Kmmdns.) Genu.s CYCLORIIINA, gen. nov. Cyclokhina NOBILIS, Hull. Fig's. 1. 2, 4, ."). Ventral, protile, dorsal ami cardinal views of a youngs shell; showing the obtuse umbones, deeply truncated beak of the iiedichwalve, straight cardinal line, and low median fold and sinus. Fig. 3. The interior of the umbonal jiortinn of the bi'arhial valve ; showing' the divided hinge-plate and its thickened latei'al divisions. X ^• Figs. 6-9. Pi'otile, ('.irdinal, frontal and ventral \iews of a mature individual. Fig. 10 An enlargement of the external surface ; .showing the tine concentric lines which crenulate upon the crest of each plication. X K. Hamilton group. Thedfvrd, (hifaria. Fig. 11. The interior of an incomplete pedicle-valve; showing the teeth, and the scars of the jiedicle, adductor and diductiu' muscles. Fig. 12. A weathered specimen ; showing the cavities occupied by the ci-iira. H;imiIton gi-oup. Darien, N. 1". Genus EATONIA. Hall. Fide Jul. K.vTi-NL\ f;iN(!UL.\i;is. V;iini.\(iii. Fig. 13. Ventral view of an unu.sually large specimen. Figs. 14-lli. Cai'dinal, frontal and prcjtile views of a normal example. Lower Helderberg group (Shaly limestone). Alhani/ coiiiily, N. Y. Eatonia PECULiAUi.s. (_'i)nrad. Fig. 17. Dorsal view of an average speinmen. Lower Helderberg gi-oup (Shaly limestone). Albany county, N. Y. Fig'. IS. The interior of a brachial valve, viewed in i)rotile from the front ; showing the elevation of the cardinal process, its lobation and the crura. Fig. 19. An internal cast of the i)eiis mil' m ) A ■■JQiCk^ R.P \Vhitfield del Phil.AsiUtli. Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Figs. 7, Fig. 9. PLATE LXII. (Figures 1-5, 8-10, 14-1(1, 21-i:!, 37-4.1, ai, 53 by E. Emmoss ; 7, S, ll-i:j, 17--.;o, ■J4-' . 4i; ."il l>y (i. li. siMi'sox.) Genus SYNTROPHIA, gen. xov. Page -na. Syjjtrophia lateralis, Whitfield. 1. The exterior of a pedicle-valve ; showing the long, straight hinge hkI broad median sinus. . The exterior of a Ijrachial valve ; showing the broad, obscure nieuian fold. , The exterior of a small pedicle-valve. A portion of the interior of the pedicle-valve ; showing the cardinal area and spondylium. X ■?. Cardinal view of conjoined valves which have been transversely sectioned in the lunbonal region ; showing the spondylium in both valves. The shell has been cut just in front of the support- ing septa, the bi-achial valve lieing aljove. X -• Caniinal view of the specimen represented in tig. 1 ; sliowing the cardinal ai'ea. 8. Internal casts of two brachial valves with impressions of vascular sinuses. , A portion of the interior of the pedicle-valve ; showing the complete spondylium and the division of its surface into median (adductor) and lateral (diductor) muscular areas. X 3. Fig. 10. Oblic^ue view of the specimen represented in fig. 1 ; showing the ele\ation of the spondylium and the length of its supporting median septum. Calciferous formation (F ^ ^ ^ Plate LXll II 12 l.B. Simp son del riiilAstJith. PLATK I.XII— CoutinuiMl Subgenus CAMAROPHORELLA, s.-gen. nov. Page 215. Camakophorklla LKNTICULAKIS, While ;ill(l Wllilticlil. Fig. 46 All iiiteraal cast of the pedicle-valve ; showing' the cavity left by the spondylium anrachial valve, and of the spondylium and its median septum in the pedicle-valvage231. CONCHIDIUM NySIUS, IIllll ;lll(l Wllitflcld.* 8ee foot-note on page 235. Fig's. 1, 2. Dorsal and profile views of a small, coarsely plicated shell. Figs. 7, 8. Dorsal and profile views of a large individual. Niagara grotip. Near Lauwmlle, Kenhwky. CoxcniDiuM TENUicosTA, Hall and Whitfield. Figs. 3, i. Dorsal and cardinal views of an adult specimen, showing the outline, contour and tine plication of the surface. Fig. 5. Dorsal view of a young individual. Niagara group. Near Louisville, Kentucky. CONCHrDIUM MULTICOSTATUM, ILlll. Fig. 6. Doisal view of an internal cast; showing the fine plication about the margins. Niagara group. Waukesha, Wisconsin. CONCHIDIUM LiTTONI, Hall. 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 unibonal region. Niagara group. Hardin cou7i,ty, Tennessee. CoNCHiDiUM Knappi, Hall and Whitlield. Figs. 11, 12, 13. Profile, dorsal and cardinal views of the original specimen ; showing the contour and du- plicate plication of the valves. Niagara group. Near Ltmisville, Kentucky. CoNCHiDiuM Knighti, Sowciby. Fig. 14. Longituiiinal section of the valves ; showing the development of the spondylia and median septa. The specimen is so liroken as to exhibit the proximal wall of the spondyliura of the pedicle- valve and the distal wall of that in the opposite valve. Amestry limestone. Near Leintwardine, Shropshire. Fis's. 15, Iti. Dorsal and profile views of an average typical example; showing the contour of the species, conspicuous and incurved umbo of the pedicle valve, and the complete plication of the surface. Amestry limestone. AymeMry, England. (Figures 14-16 after D.wil.son.) Palasonl N Y.VolIVPt ii = Vol Vm, 113 m ^ (s miL m ^ m m £^ J'ENTAMKHIDA. ( UMU'i'ic 11 lust rations PlateLXIV R.P.^Vhiu,eid. del Phil.Asthth. PLATE LXV. (Figures 1-3, fl;by G. B. SIMPSON ; 4, 6-9 by K. Emmons) Genus CONCHIDIUM, Linne. Page 231. CoNCHiDiuM DECUSSATUM, Whitcaves. Fig. 1. Ventral view of a specimen partially exfoliated in the iimlional region ; showing the fine, dupli- cate j)lication and the delicate concentric lineation of the surface. Fig. 2. Doi'sal view of the umbonal portion of an internal cast ; .showing the cavity of the spondyliuni and median sejitum of the pedicle-valve, and the genital markings about the beak. Niagara group. Grand Rap'iriit of the Saskatchetoaii River, British Aiiwrica. CONCHIDIUM LAQUEATUM, Coiliad (=PeNTAMERUS NOBILIS, KmillOlls). Fig. 3. An anterior \iew of a poi'tion of the interior, looking into the chamber produced by the union of the spondylium and septal plates j showing the curvature of the latter, their explanate upi)ei- surfaces, and the foreshortened crural apophyses. Fig. .1. Another view of the same specimen ; showing the spondylium with a portion of the median sep- tvmi adhering, and the extent of the septal plates and crural processes. Figs. 4, H, 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. Fig. 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 anterior eilge, 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. Fig. 8. An internal cast of a brachial valve which retaines the jirevailing broader form of the species. Niagara .\. ( 'cin'rir I Hu^IimIikus ■siil, cardinal anil ventral view.s of the original specimen ; .sliiiwiiiy the form of the siiell, the character of itt< [plication, it."* concentric varices ami tine f;rowth-line.«. The ilra\vin(,'S are slightly restored in the iinibonal region of the pedicle-valve. Kig. 4. A lateral view of the .same s])e(;imen, in which the median .septum and siiomlyliom of the pedicle- valve are exposed. Niagara group. Near LuuisvUlc, Ketituckii. CoNCHiDiUM, .sp. indi'f. Fig. 5. An internal cast of a small pedicle-valve, with a coarsely plicated siirfa<;e ; showing the apical portion of tlie (illing of the spondylium and a somewhat distorted median septum. Niagara dolomites. Near Milwaukee, WiscoJi.thi. CONCHtDIUM EXPONENS, !i\). IIOV. Figs. 0-9. Inteiiors of pedicle (tigs, 6, 7) and brachial (tigs. 8, 9) valves of a strongly costate shell ; sho\ving the structure of the interioi'. Niagara group (Halysites Ijed). Louixrille, Kentucky. CONCIHUIUM MULTICOSTATUM, Hull. See Plate 64. Fig. 10. A profile of the onginal specimen, an internal cast. Niagara ilolomites. Wauvaiitotta, fViftcoiiJiiii. CONCHIlJll.M lilLOCULARK. LillJie. Fig. 11. Dorsal view of an average example ; showing the form of the shell, character of the surface, and retaining a portion of the deltidium. Fig. 12. A profile of the same specimen ; showing the long, coiii'ave and smooth cardinal slopes. Fig. 18. A natural longitudinal section of conjoiiHMl \al\'es; showing the relation of the spondylium and septal ]ilates. Fig. 14. Ventral view of the same individual ; showing the length of the meili.nn septum. Upper Silurian limestone. Inland of Gntland. CONCHIUIUM DECUSSATUM, WilitcilVOS. See Plate 65, figs. 1. 2. Fig 15. Dorsal view of a small example ; sho^ving the foi'm and exterior chai-actei-s of the species. Niagara dolomites. Rapicls of the i?askatcheioan liUvr, British America. CONCHIDIUM COLLETTI, j\IilU'|-. Figs 16, 17. Ventral and proHle views of a pedicle-valve ; showing the line pliiation. freiiuent imiiricating growth-varices, and the expanded anterior margin. Niagara limestone. Indiana. CONCHIDIUM GeORGI/E, .sp. IIOV. Figs. IS, 19. Dorsal and cardinal views of the brachial valve ; showing the conspicuous median fohl and the plication of the siu'face. Clinton group. Trentim, Georgia. PLATE LXVI— Ck)ntinued. CoNCHiDiuM Greenii, sp. nov. Figs. 20-22. Profile, cardinal and ventral views of a specimen somewhat restored about the margins ; showing the short, ventricose valves and fine, duplicate plication. Niagara dolomites Near Milwaukee, Wisconsin. CoNCHIDIUM, tjJJ. Fig. 23. An internal cast of the pedicle-valve of a probably undescribed species ; showing the character of the plication and the length of the median septum. Niagara dolomities. Hawthorne, Illinois. CONCHIDIUM CRASSIPLICA, Sp. IIOV. Figs. 24, 25. Dorsal ami profile 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 surface. Niagara group. Prohahl i) from the vicinity of Louisville, Kejitucky. ID ia^'^:ii3fflip cDicj^. Paleeont.N Y.Vol IVPt n- Vol. VIII i'i;Nr.\Mi;iiiii.\. 1 lliistratiims tel.XVT E-Emmons del j^rii-A&V:i*Ji. PLATE LXVII. (Kiguies 1, 2, U-IH by E. EMMONS ; 3-10, 20 liy G. I!. SIMPSON.) Genus CONCHIDIUM, Linne. Page 231. CONCHIDIUM (?) OCCIDENTALIS, Hull. Figs. 1, 2. Ventral iiml pruKlc views of a specimen retaining- a iiortion of the .«liell in a somewhat mace- rated condition ; showing the form of the species and faint traitea of plications over the anterior siii-face. Fig. 3. A portion of the extei-ior surface enlarged ; sho%ving the irregular lamellose concentric growth lines and the faint radial plications. X 2. Fig. 4. Profile of the umbonal portion of both valves, that of the pedicle-valve retaining its normal con- tour and showing its great elevation, conspicuous incurvature and uniform contour. Fig. .5. Dorsal view of an internal cast of a somewhat distorted example ; showing the impre.ssions of the septal plates in the brachial valve. Guelph dolomites. Gait, Ontario. CONCHIDIUM SCOPAKIUM, SD. IIOV. Figs. 6, 7. Dorsal and venti'al \ lews of a specimen retaining much of the shell; showing the outline of the species and preserving a very distinct and rather fine radial plication. Guelph dolomites. Dwrham, Ontario. CONCHIDIUM OBSOLETUM, Sp. IIOV. Figs. 8, 9. Venti'al and dorsal views of an internal east of a species pos.sessing a few low and broad plica- tions. The figures show the length of the median septum in the pedicte-valve, and the position of the septal plates of the brachial valve, and also the adductor muscular scai-s of the latter, a feature which is rarely retained with distinctness in this genus. Niagara dolomites. Getwa, Ottawa county, Ohio. Genus PENTAMERUS, Sowerby. Page 236. Pentamerus PERGIBBOSUS, Hall and Whitfield. Fig. 10. A view looking into the umbonal cavity of conjoined valves ; showing the spondylium and its supporting septum below, and the crural processes of the brachial valve above. The spondy- lium is extremely narrow and deep, having scarcely, greater width than the supporting septum. Niagara dolomites. Near Chicago, Illinois. Fig. 14. Cardinal view of an internal cast of a large individual ; showing the relative depth of the valves and the cavities left by the spondylium and septa. Fig. 15. Profile ^ew of a similar internal cast ; showing the normal contour of the species. Niagara dolomites. Near Milwaukee, Wisconsin. Fig. 16. Cardinal view of an internal cast of a small shell, which shows with much distinctness the posi- tion and form of the deltidium. Chert of the Niagara group. IVwcoimn. Fig. 17. Profile of a small and gibbous internal cast, having somewhat the form of the P. obloiigu.'i, var. Maquoketa (see tigs. 11-13), but less regularly convex. Figs. IS, 19. Cardinal views of internal casts ; showing the variation in the convexity of the valves and the position of the internal apophy.ses Niagara dolomites. Near Milwaukee, Wisconsin. PLATE LXVII— Continued. Pentamerus oblongus, var. Maquoketa, vai-. iiov. Figs. 11, 12. Dorsal and profile \-iews of an internal ca-st of a characteristic example ; showing the ovoid and regularly convex valves. Fig. 13. A cardinal view of another individual ; showing the position and e.xtent of the internal plates. Niagara dolomites. Near Diibagite, Iowa. Pentamerus oblongus, Sowerliy. Fig. 20. The interior of the umbonal portion of a silicified shell ; showing the spondylium and median septum. Niagara dolomites. Hillsboiv, Ohio. m m =iv, ;.E :ii ic b if © im ^ Palceont N Y Vnl TVPl !i = Vo! VIII I'll.N TAMl'.HIIl.V. (i.-n.Tii lllusli.ilii) Plate LXVII / ,^ -"Hji^. .^ / I > ^, 16 / •Z' lt^ / \ )S ■?^f#^"'" GB.Simpsmi del PLATE LXVIII. (FigurCb 1-8 by E. EMMON8.) Genus PENTAMERUS, Sowerby. Page 236. Pentamerus oblongus, Sowerby. FigB. 1, 2. Dorsal views of two shells ; showing: the variation in outline assumed by the species at this local- ity. Fig;. 1 (see also plate Ixix, fig. 7) apjiroaches the subquadrate outline of P. ohlongus, var. suhrectus (see fig. 6 and plate Ixix, figs. 8-10), but has less conspicuous umbones and less con- vex valves ; fig. 2 has a peculiarly triangular outline, which is I'eproduced with a strongly trilobate anterior margin in the larger specimens from Yellow Springs, Ohio (see figs. 3-5). Clinton group. MocJiester, New York. Fig. 3. Dorsal view of a large, elongate shell, with a broad median lobe. Fig. 4 Ventral view of another sjiecimen of similar character, the two lateral grooves defining the median and lateral lobes Leing very strong. The .specimen shows the ca\-ity of a very short median .septum. Fig. 5. Dorsal view of a smallei' 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 \ery faint and have been made much too conspicuous in the figure. Niagara dolomites. Yellow Siyri?i,gs, Ohio. Pentamerus oblongus, var. suhrectus. var. iiov. See Plate Ixix. Fig. 6. Dorsal view of a large individual of this vanety slightly imperfect at the anterior margin j show- ing the subquadrate outline, medially convex and broadly lobed valves. Niagara beds. Jones county, Iowa. Pentamerus oblongus, var. cylindricus, Hall and Wliitlielcl. Figs. 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. Utiva, Indiana. Palaoni N YVolIVPl li- Vol.Vm. 33 Ili^SSIHmiF ©iBJi^ I'ANTAMKIIID.Y ricufi-u- llliislr.ilioiis Plate L> VI] J • S^^llj, fn f *v M' V il* ^W- V ■ -fcj Emmons del Phil.Astlith. PLATE LXIX. (Kiguies 1-10, 13 liy G. B. SIMPSON; 11, 12 by K. P. Whitfield ) Genus PENTAMERUS, Sowerby. Pago 236. Pentamerus oblongus, Sowerby. Fi^. 1. Dorsal view of an internal cast of a small shell, broadly trilobed and having- a similar outline to young forms of the \-ariety suhrectus (see tigs. 2, 8) though with much shallower valves. Niagara dolomites. Richmond, Indiana. Pentamerus oblongus, vur. subrectus, vnr. nov. See Plate 68. Figs. 2, 3. Dorsal and ventral views of a small specimen of subquadr,ate outline, trilobed exterior, and showing the single median septum in both valves. Figs. 8-10. Dorsal, jirofile and ventral views of a normal 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 Gfrove township, Jones eounty, loioa. Pentamerus oblongus, .Sowerby. Figs. 4, 5. Dorsal and ventral 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 ryiindrii-us. This shell occurs in the chert of the Ma(iuoketa region near Dubuc^ue, Iowa, liut not in immediate asso- ciation with the var. suhrectus. Niagara beds. Jones county, Iowa. Fig. B. Dorsal view of the umbonal region of an internal cast in chert ; showing the cavities left by the septum and septal plates, the deltidium and the latei'al divisions of the hinge-plate. X 2. Niagai-a beds. Monmouth, loipa- Fig. 7. Ventral view 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, vur. cyllvdricus. Hall iiiul Whitliekl. Figs. 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, Sowerliy. Fig. 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. Fig. 14. An outline sketch of a large brachial ^•alve having the broadly ovate form and trilobed exterior of the specimens from Yellow Springs, Ohio, represented on plate Ixviii, figs. 3-5. Niagara dolomites. Probably from the vicinity of Richinond, Indiana. ID Ili^(B2IIS(DIP (BIB^ Paleeont. N Y.Vol TVPt n = VQLV!II PENTAMKHIDA". ( 't'lUM-ir Illustr;iti(m*i Plate LXIX E Emmons del. Phil.AsthUi. PLATE LXX. (Figures 1, 2, HI by E. Emmons ; 3, copy.) Genus PENTAMERUS, Sowerby. I'age -mi. Pentamekus oblongus, Sowcrhy. See plales Ixviii, Ixix. Fig. 1. Dorsal view of an internal cast of a broadly ovate shell, with evenly convex valves. Niaf^ara dolomites. Near .Vilwaukee, JVisivnshi. Fig. 2. A natural longitudinal section through both valves ; showing the comparatively short median sep- tum and septal jilates, the projecting spondylium and crui-al processes. Clinton group. RocJiesttr, New York. Fig. 3. A copy of the original figure of this species given by Murchi.son in "Silurian System," plate xix, figure 10. Fig. A. Dorsal view of a large, elongate-sviliovate shell, with trilobed surface, broadly shouldered um- bones and closely incurved an(i depressed ventral beak. Clinton group. liochtster, New York. Pentamerus oblongus, v;ir. subrectus, vai-. iiov. See plates Ixviii, Ixix. Fig. 5. 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 connty, Iowa. Genus CAPP^LLINIA, gen. nov. Page 348. Capellinia mira, .sp. uov. Figs, t), 7. Ventral and cardinal views of an avei'age specimen : showing the i)redominant convexity of the brachial valve, the smooth surface and the position and extent of the interna! plates. Fig. 8. Cardinal view of another example in which the convexity and lunbonal incurvature of the Ijrachial \-alve are still more conspicuously developed. Fig. 9. Cardinal view of a pedicle-valve ; showing the inconspicuous, suberect beak and wide delthyrium. Fig. 10. Ventral view of the same sjiecimen ; showing the length of the median septum. Fig. II. Profile view of a normal individual ; showing the relations of the valves. Figs. 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 i)lates and a low radial plication over the uni- bonal region. Niagara dolomites. Near Milwaukee, Wiseon.nn. m im ^ 'is HI 2 © 2P Q IS) ^ Palseont N.Y.Vol IVPt 11 = Vol.VlII. i'i;.\r.\Mi;itii).v. ( 'tnu'Tlf IllllsllMlKJllS Plate LXX -^""l^ n. i 4 •% '^ -fi.. £. Emmons 6c PLATE LXXI. (Figures l-;i (jopies ; i, .), H-XI l)y \l 1'. Wiiiti'ikld ; li-lll. 11-lH, 3-t-as hy G. li. Simpson ; 11-13, n-ii by K. Kmmons). Genus BARRANDELLA, gen. nov. Page 241. Bakkandella linguifera, Sowerby. Figs. 1, 2. Dorsiil and inolile views of a normal individual ; showing th« cliai-ai;toi- of the exterior and the well defined median fold on the brachial valve. Fig-. 3. A longitudinal median section of the valves ; showing the small sjiondylium and (ixtremely short median septum of the pedicle-valve, and one of the septal plates of the brachial valve. Wenlock limestone. Dudley, Enyland. (Figui-es l-,5 after Davidson ) Bauuanuella ventkicosa, Hall. Figs. 4, 5. Front and dorsal views of a typical example ; showing the fold upon the Virachial valve, its faint plication, and the cavities of the median sejjta. Niagara dolomites. Waukeslia, )Visco'i/^iii. Figs. 6, 7. Ventral and profile views of a ventrico.se specimen \vith a low sinus on the pedii-le-valve. Figs. 8-10. Dorsal, profile and front views of a smaller individual having the fold and sinus distinctly plicate. Niagara dolomites. Near Miiwaukee, WiscoTusm. Bakkandella foknicata, Hall. Figs. 11-13. Profile, dorsal and ventral views of the exterior of a specimen of avei'age size ; showing the median fold on the brachial valve, the single broad plication in the sinus of the pedicle-valve, and the faintej- plication of the latei-al slopes. Clinton group. Lockport, Neio York. Bareandklla Areyi, .s[). nov. Figs. 14-16. Dorsal, profile and ventral views of a normal example ; showing the strongly plicated fold and sinus on the brachial and jiedicle valves respectively, and the sharp plication of the lateral slopes. X 2. Clinton grou]i. Bocliesier, New Y(yrk. Bakrandella Barrandii, Billings. Figs. 17, 18. Dorsal and ventral views of a large and typically developed individual ; showing the broaENr.\.\IKltIllA-. ( >>-lM'l H lllil'.tl .illiMI- Plate LXXl > ^ yia.- ^^ ■I .! f H!l .AS' / J Id 13 fel G.B.Simpson del Pali.Ast.lith. PLATE LXXII. (Kigures 1-3, IS-20. 3J, ii by 11. P WHITFIELD; 4, 5 copies; li-9, -^4. 27-33 by E. Emmoss; 10-U by F. B. Meek; 15-17, 21, Jfl, 21) by G. K. Simpson.) Genus SIEBEKELLA, CEhlert. I'age 241. SlEBERELLA NUCLEUS, Hilll Uiul Wllltficld. Figs. 1-3. Doraal, profile and iVont views of the oritfinal specimen ; showing- the form of tlic shell and the strong plication in the median sinus In limestone of the age of the Clinton group. Near LouisviUe, Kentucky. SlEBERELLA SlEBEKL VOll Bllcll. Figs. 4, 5. Dorsal and front views of a typical mature example ; showing the strong plii'ation of the sur- face and the sinus in the bi'achial valve. Lower Devonian (Etage Fa). Koniepriis, Bohemia. (After Bakhande.) SlEBERELLA RoEJiERi, uoiii, iiov. (Penknueiu.'i ffcdecUm, F. Roeiuci). Fig. 6. Dorsal view of an individual of rather large size ; .showing the characteristic plication of tlie sinus and lateral slopes aViout the margin, and their obsolescence in the umtjonal i-egion. Upper Silurian. Perry county, TetiTiessee. SlEBERELLA GALEATA, Dulnillil. Figs. 7, 8. Dorsal and profile \-iews of a well-developed example, with transverse form, highly convex valves, typically developed plicated .sinus and obscurely plicated lateral slopes. Fig. 9. An enlargement of the external surface of the same specimen ; showing the tine, irregularly anas, tomosing concentric raised lines. Wenlock limestone. Dudley, England. Figs. 10, 11. Profile and dorsal views of an elongat^; shell with plicated sinus and smooth lateral slopes. Fig. 12. A view of the interior of conjoined valves ; .showing the spondylium and its sujiporting septum, one of the sejital plates and its crural j. rocess. Fig. 13. Cardinal view of a large intei-nal cast of both valves ; showing the cavities left by the spondyl- ium and septum in the jiedicle- valve, and by the septal \ lates in the brachial valve; also the genital markings in the umlxmal region of the pedicle-vane. Lower Helderberg group. Tfte HeUlei'berg.f, Nexo York. SlEBERELLA PSEUDOCiALEATA, Hall. Fig. 14. Profile view of a typical specimen ; showing the absence of surface plications. Tlie representa- tion of radial lines in the drawing is erroneous Lower Helilerberg gr. PlateLXXli E-Emmons del. Phil.Asihili. PLATE LXXIII. (Kisures l-lii, H-['.> by E. Kmmdxs ; II liy (i. 1!. Simpson ; 12, l:i, iu by It. P. WiiiTFiKLU.) Gknus STRICKLANDINIA, Hillings. Stricklandixia multilikata, Wliittield. Fi^s. 1, 2. Ventijil ami iloisiil views of an inti-rnal silii-ious cast. The Hjjures show the hIioH, straight hing-e, the sharj) delimitation of the cardinal I'egion and the orbicular outline of the valves. In figure 1 is seen the low median groove and the apex of the tilling of the spondylium ; figure 2 shows the median fold of the brachial valve and the cast of the small but prominent muscular scar. Niagara dolomites. Near Milwaukee, Michigan. Stricklandinia castellana, Wliite. Figs. 3-G. Doi-sal, profile, cardinal and vcmtral \ie\vs of a characteristic specimen ; showing the nearly equiconvex valves, the strong, irregularly fasciculate or dujjlicate 'plication, and, in fig. 5, the cavities left i)y the spondylium and low median septum of the pedicle-valve. Fig. 7. Cai-dinal view of a partial internal cast, the pedicle-valve being represented beneath ; showing the position of the spondylium and its supporting septum and the casts of the muscular im- pressions on the brachial valve. Niagara group. Jones county, lima. StkicklaiNdima dkformis, Mcuk mill W'oriluii. Figs. 8, 9. Profile and cardinal views of an internal cast ; showing the delimitation of the cardinal area of the pedicle-valve and the filling of the spondylium. Fig. 10. Dorsal view of the umbonal portion of a specimen, to show the short, straight hinge-line and the subauriculate cardinal extremities. Niagara group, A'i. Charles, Illinois. Stricklan'ijinia Gaspensis, Uilliiig.s. Fig. 11. Dorsal view of a large individual, drawn from a plaster cast of the original specimen; showing the form of the shell, a jjortion of the caroual portion of the brachial valve; showing the septal plates, the four sharjily defined scars of the adductor muscles, the \ascular sinuses and genital markings. Corniferous limestone. lVe,^(siiiaa)ip oiEic^ Palasont , N Y.Vol. IV Pt 11= Vol VIU IIKNSSKI.AKHin.V. < iiMHTir iniisli-.itiiiii-; Plate LX XV £, HI I. m iU!^ ^ \ w **t)!i I f- ^1 f G B.SimpbuPL del Phil-Asthth. PLATE LXXVI. (Figures 1 3a. 'J, .il-:;4 by It. 1'. WiinriKLD; 4-7, 20 by E. Emmons; 8, U-l'), 17, iV28 Ijy F. B. Mkkk; 10, 16, 18, I» l)y G. B Simpson.) Genus RKNSSEL^RIA, Hall. I'age 2.')+. liENSSELiKUI.V MUTABILIS, H:lll. Pigs. 1, 2. Dorsal and profile views of a ratliL'r larfji" 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 lamelUe, and the median ridge along the line of coalescence of these ))arts, produced upwardly and po.steriorly into a free exti'emity. Lower HeUlorberg gi'oup. Bc.i-raft's Muuiitahi, Columbia county, JYeio York. Genus TRIGERIA. Bayle. Page 265. Trigeria Portlandica, Billiiig.s. Figs. 4, 5. Dorsal and venti-al ^aews of the original specimen of Mensselaeria Porllitiidku. Billings, which is tentatively referi'ed to the Genus TRinERiA. Lower Helderberg group. Square Lake, Maine. Trigeria Gaudryi, OEhlert. Figs. 6, 1. Dorsal and profile views of an internal cast, provisionally referred to this species ; showin.;- 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 brachial valve. In fig 7 the convexity of the valves is not satisfactorily represented, the bi-achial valve being too convex and the opposite valve not convex enough. OrLskany sandstone. Cwmherland, Maryland. Genus RENSSEL^RIA, Hall. Page 254. Renssel^ria Marylandica, Hall. Enlarged view of the cardinal portion of the pedicle-valve; showing the foramcm and deltidial plates. Dorsal view of a typical exterior ; showing the fine surface plication and the oval outline of the valves. Dorsal view of another individual, less sharply plicated and having a less convex brachial valve. The interior of a nearly complete pedicle-valve ; showing the deep and strong dental lamella? restino' upon, though not consolidated with the bottom of the valve, and the elongate muscular impressions. 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. The interior of the brachial valve ; sh'owing the medially divided hinge-plate and the loop with its long, acutely triangular anterior plate and median ridge with its short and fi-ee posterior extension. Profile of the specimen represented in fig. 11 ; .showing the convexity of the valves. The cardinal portion of the brachial valve ; showing the form of the hinge-iilate, the obsolete N-is- ceral foramen, and the anterior 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 Fig. 8. Fig. 10. Fig. 11. Fig. 12. Fig. 13. Fig. 14. Fig. 15, Fig. 17. PLATE LXXVI— Continued. 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 sui'face largely obscured from the same cause. Fig. 20. The interior of the uraljonal jiortion of the pedicle-\-alve ; showing the dental plates and muscular impressions. Oriskany sandstone. Cuiaherland, Maryland. Gknus AMPHIGENIA, Hall. Page ■'.W. Amphigenia elongata. Hull. See Plates 73, 74. Fig. 9. The cardinal portion of the brachial valve : showing the form of the hinge-plate, its median depression, the ojiening of the visceral foramen, a portion of the septal plates and the branch- ing vascular sinuses. Corniferous limestone. Le Hoy, New Ym-k. Genus RENSSELJ^^RIA, Hall. Page 254. Renssel^ria ovoides, Eaton. See Plate 75. Fig. 16. The hinge-plate enlarged ; showing its foi'ni, 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. Rensseljcria mutabilis, Hall. See figures l-3a. Figs. 21, 22. Dorsal and profile views of a broad, ovate form \vith elevated umbo, open delthyrium, well- defined cardinal slopes and rather coarse surface plication. Lower Helderberg group. Becraft's Mountain. Coluinhia county. New Yo)-k. Rensseljdria jequiradiata, 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 (Upjier Pentamei'us limestone). tSchoharie, New York. Ren.ssel^kia elliptica, Hall. Pigs. 26, 27, 28. Dorsal, profile and front views of the original specimen ; showing the form and convexity of the shell. Lower Helderberg group (Shaly limestone), fichohane, Neio York. m m J:^ a li.v K. 1!. 1\Ii:i:k ; 1", 11, 17-3-2 by G. B. SijipsoN ; li-U liy K. r. \V ii rn- 1 i;li> ; 20-28 by F. J.SWINTON.) Subgenus BEACHIA, s.-gen. nov. Page 2iiu. Beaciiia Suessana, Hall. Fii;: 1. Tlie interiors of two iiedlcle-valves, the upper retaining- the deltidial plates, the lower having- lost tho?e 1 lutes, but sliowing- the dental lamellie. Both tig-ures show an obscure musculai' area divided by a low median ridg-e. Vig. 2. The interior of a biacUial "\alve -, showiiifT the hing^e-iilate. nicdi.-iUy de|>i'essed and pei-forated at its a|iex liy tli(; visceral for.-inien, the dental sockets, and the form of the loop with the meilian roil-like process extending- backward and npwai-d fi-om tlie anterior plate. . Front view of conjoined valves ; showing the fine plication of the surface and the inflexion of the lateral margins, . Median lony-itiidinal section of conjoined valves; showing in profile the loop with its long, erect (•rural apopliy.ses, the elevation and direction of the median proi-i>ss extending backward from the anterior plate. . Views of the interior of two brachial valves ; showing the inflei-ted lateral margins and some vari- ation in the comlition of the hing-e- plate. 7, 9 Ventral, pi-ofile and dorsal views of a typical example ; showing the outline, contour and plication of the valves and their lateral marginal inflexion. . Profile of a smaller shel'. with tlie mai-ginal infiexion of the valves extending to the anterior ex- tremity. , 11. Views of the liing-e-]ilate in two individuals ; showing difterences due to age ami consequent thickening of the parts. X '2. Oriskany sanilstone. Owmherlanrl. Maryland. (iENis MEGALANTERIS, Suess. P.age ill. Megalanteuls ovalis. Hall. Fig. 12. An internal cast of the pedicle-v.alve ; show-ing the filling of the deep scar of the diductor muscles, enclo.sing the small sub(;ordate addui-.toi- .scar, with traces of vascular sinu.ses and genital markings. Fig. 13. The dorsal side of an internal cast; showing the deep impression of the prominent hinge-plate and cardinal process, and the ailductor muscular scars. Fig. 14. A similar view of another .specimen to which a portion of the pedicle-valve adheres i showing the cavity of the hinge-plate and the 4r /i f \ t^''\'W¥rA v\Jl X /'■ RP.V\'hitlielddel PkL.As". iii>L. PLATE LXXVIII. (rigiues 1-9, 17-23 by G. B. SiMI'Sos; 10-16 by U. 1' WmrFitLD.) Genus NEWBERRIA. Hall. Page 261. Newberria Clayi'olii, Hiill. Fig. 1. An internal ca.st of a portion of the pedicle-valve ; showing- the divergent impressions of the dental lamella;; the irregularly divided scar of the adductor muscles ; the narrow anterior adductor and strong vascular impressions. Fig. 2. A portion of the interior of the bracdiial valve, drawn from a gutta-percha impression of a natui-al internal cast ; showing the division of the hinge-plate, and the st'iated adductor impressions. Fig. 3. An internal cast of a small pedicle-vaive in which the impressions of the vascular sinuses are very strongly developed. Fig. 4. An internal cast of a brachial valve preserving the usually elongate form of mature individuals, and showing the muscular and vascular impi-essions. Fig. 5. The interior of a pedicle-valve, from a gutta-percha impression ; showing an open delthyrium, the divergent dental ) lates, the mus(udar and vascular impressions. Fig. 6. An internal cast of the pedicle-v.alve ; showing the impression of the apical cup-shaped depression of that valve. By the i-emoval of the tilling of the dental sockets, the cardinal slope is made to appear unusually large and tiat. Fig. 7. An internal cast of a large and symmetrical pedicle-valve. Fig. 8. An internal cast of a large and somewhat deforaied brachial valve, which shows the usual size and division of the hinge-plate and the character of the adductor scars. Fig. 9. An internal cast of a pL>dicle-va!ve in which the muscular scars and vascular .sinuses, both pri- mary and secondary, are highly developed. Sandstones of the Hamilton group. PeiTy cotmtij, Pennsylvania. Newberria Johannis, Hall. Fig. 10. An internal cast of the umbonal portion of a pedicle-valve, with the muscular and vascular mark- ings distinctly retained. Fig. 11. An inteiTial cast of the upper portion of a brachial valve ; showing the ca\ity left by the di\ided hinge-plate and the adductor muscular scai-s. Figs. 12. 13. Doi-sal and ventral \iews of a large and chara<;teristic specimen ; .showing the elongate-oval form, the decided median angulation of the valves and the rugose concentric growth of the surface. Fig. 14. The exterior of a pe-38 by O.K. Simpson; 25-27, .U-M, 39 by K. Emmons ) Genus CENTKONELLA, Billings. rase 265. C'ENTHONEI.LA GLANS-FAGEA, Hull. Fig-. 1. Dorsal vii'w of :i lai-g-e individual. Figs. 2 -4. Doi-sal, V(?ntral and jirolile views of a small specimen, havinff a more elong-ate outline than the preceding ; .showing the convexo-concave contour. X 3. Schoharie grit. A/bany comity, Neio Ymk. ¥\^. 5, t). Dorsal and pnitile views of a very ventricose individual having the elevated character of C. tumida, Billings, but of smaller size. Corniferous limestone. Cayuga, Ontario. Fig. 7. An internal cast ; showing impressions of the hinge-i)late, dental sockets and mnscular scars of the brachial valve. X 2. Schoharie grit. Albany co%mty. New Ymh. Fig. 8. Dorsal view of a specimen having the brachial valve quite Hat. X 2. Corniferous limestone Drift, near Ann Arbor, Michigan. Figs. 9, 10. Protile and inner views of the loop and its attachment ; showing the di\-ided hinge-plate and the narrow anterior expansion of the loop with its median I'idge. X 5. Corniferous limestone. Tl'f.v/ertt New Tork. Figs. 11, 12. Dorsal and protile views of a \ery gibbous shell, which shows the foramen and deltidial plates. Corniferous limestone. Drift, near Ann Arbm, Michigan. Fig. 13. An internal cast of the pedicle- valve ; showing the impressions of the teeth and the deep scar of the_-pedicle-muscle. the anterior extremity of which is enclosed by the diductor scars. X 2. Schoharie grit. Albany county. New York. Fig. 14. Doi-sal view of an internal cast ; showing the muscular scars and the impression of the hinge- plate. X 2. Corniferous limestone. Drift, near Ann Arbor, Michigan. Fig. 17. The interior of the umbonal portion of the brachial valve ; showing the thickened divisions of the hinge-plate and the adductor scars. X 3. Fig. 21. The interior of a brachial valve; showing the hinge-plate and the variation in the form of the muscular scarb. X 3. Corniferous limestone. Cayuga, Ontario. Centronella Hecate, Billings. Fig. 15. Doreal view of a specimen ; showing the elongate form and general similarity to C. impressa. Hall, with which it may be identical. Corniferous limestone. Cayuga, Ontario. Centuonella impressa, Hull. Fig. It). Dorsal view of an average individual ; showing the form and concave brachial valve. Fig. 18. The interior of the pedicle-valve, retaining the deltidial plates and teeth. Fig. 19. The interior of a brachial valve ; showing the greatly thickened divisions of the hinge-plate, and the minute cardinal process. Fig. 20. The interior of a brachial \-alve ; showing the divided hinge-plate, the elongate muscular scars and the vascular sinuses. X 2. Hamilton shales. Bellona, New York. Centuu.vella alveata. Hall. Figs. 22-24. Doi'sal, protile and ventral views of the original specimen ; showing the large size, elongate form and deep median fold and sinus. Onondaga limestone. Locality .' (New York). I'LATE I.XXIX— Contiuueil. Genus ORISKANIA, gen. nov. Page '205. Oriskania navicella, sp. nov. Pigs. 25-27. Dorsal, profile and \entral viows of the exterior ; ■■showing- the elongate form and plano-convex contour of the specie.s. Oriskany sandstone. Hondaitt, Neio York. Genus ROMINGERLNA, gkn. nov. I'age 2().). Romingerina Julia, A. Wiiichell. Fig. 28. Dorsal view of a large internal cast ; showing the form of the shell and the impression of the divided hinge-jilate, X 2. Figs. 29, 30. Dorsal and profile views of a smaller internal cast ; showing the conv'exity of lioth valves. X 2. Marshall group. Pointe aux Barques, Michigan. Genus CRYPTONELLA, Hall. I'age -2^6. Crvptonella (?) iNCONSTANS, HciTick. Figs. 31, 32. Dorsal and ventral views of a .small internal cast ; showing the form of the shell and muscular mai-kings. Wa\erly group. Medina county, Ohio. Genus BEECHERIA, gen. nov. I'age 300. Beecheria D.4VIDSONI, iiom. nov. Figs. 33, 34. Doi'sal and profile views of an average si)ecimen. Fig. 35. Dor.sal view of a more elongate shell. Fig. 36. The internal cardinal structure exposeil by the remo\al of a portion of the pedicle-vahe ; show- ing the absence of dental plates in the valve, and the structure of the loop. X 3. Carboniferous limestone. Windsor, Noin Scotia. Genus HARTTINA, oen. nov. Page i:n. Harttina Anna, Hartt. Figs. 37-30. Dorsal, profile and venti'al views of a well-jireserved example ; .showing the snbplano-convex contour of the valves. Carboniferous limestone. Windsor, Nova Scotia. Genus CENTRONELLA, Billing-s. Page -26.5. Centronella (?) navicella, Hall. Figs. 40-42. Dorsal, profile and ventral views of the original example, which is referred with doubt to this genus. Uliper Devonian. Rockford, Iowa. 113 m^GS3II2®T? fElJQj^i^ Palasont N-r.Vol.rv.Ptii = Vol,Vm- (■,I■■..^••n.•().\•I■.l,l,ll),\•■. (T,.niTH lllu^ll.,ll..H, Plate LXXIX RP, Whitfield de il.Astlith. PLATE LXXX. (Figures 1-17, 23-35 by K. 1'. Whitkiklli; 18-22, 36-39 by K. Kmmons.) Genus CEYPTONELLA, Hall. Page 286. Cryptonella KECTIROSTKA, HilU. Figs. 1-3. Dorsal, ventral and protile views of a amnll sliell with characteristic outline. Fig. 4. Dorsal view of a large, somewhat distorted specimen, retaining the deltidial jjlates. Hamilton .shales. Canandaigim Lake, New Yoi-k. Cryi'tonella planikostra, HmII. Fig. ."). Doi-sal view of an average specimen retaining the tleltidial plates. Figs. 6, 7. Dorsal and profile views of a large and much thickener! shell. Hamilton shales. Weste)-n New York. Figs. 8,9. Ventral and dorsal views of an internal cast ; showing the mu.scular impressions and vascular sinuses. Hamilton group. Hardy coimtij, Virginia. Fig. 10. An enlargement of the cardinal portion of the pedicle-valve ; showing the foramen, deltidial plates and teeth. Hamilton group. Mo. this species ; showing the muscular plattVirm of the lirachial valve, and the cavities of th(' dental lamellie. Choteau limestone. Cfraydan Springs, Minsvuri. DlELASMA BOVIDENS, Moftoil, Figs. 29, 30. Dorsal ami pi-ofile views of a rather gibbous specimen ; showing the contour of the valves and the i.jblique foramen The concentric surface lines appear to be to some extent color-markings, and not infrecjuently faint traces of a radial coloration are discernible in the shelLs. This specimen is of about the average size of the species as it oceui's at this locality. Upjier Carbonifei-ous. Kansas Oity,J!i'IUsouri. PLATE LXXXI— Continued. Fijj. 31. Dorsal view of an internal cast of a narrow and elongate shell, in which tho impression of the muscular platform of the brachial valve is sharply defined. Fig. H2. A gutta-percha impression made from the same specimen ; showing the collar or inverted lamella alKuit the foramen, a portiiin of the dental plates and the form of the muscular platform. Upper Carbcmiferous limi'stone. iSontfiem Indiana. Figs. 33-3.5. Profile, dorsal and venti'al views of a large and characteristic example ; showing the curvature of the valves, the bi'oad concavity of the pedicle-valve and the reflexion of the anterior mar- gins ; also the oblique foraminal aperture. Upper Carboniferous lime.stone. HarHson nmnty, Missouri. DiELASMA. .sp. ? Fig. 36. Cardinul view of a specimen enlarged to show the obliijue opening of the jiedicle-passage and its cross-striated surface. X 3. Fig. 37. An internal cast of the brachial \al\e ; showing the form and striation of the muscular platfoi-m. X3. Chester gi-oup. Caldwell county, Kentucky. DiELASMA OBOVATA, Sp. UOV. Figs. 38-40. Doraal, profile and ventral views of a specimen having the aspect of D. fnrmosa, liut said to he from the Coal Measures. Coal Measures. Kentucky. Genus CRYPTONELLA, Hall. Page 281;. Cryptonella subelliptica. s]). nov. Figs. 41-43. Dorsal, profile and ventral riews of a large internal i'a.st in iron-stone ; showing the form, con- tour and muscular .scars of the brachial valve. Waverly group, ifs'ciotomlle, OMo. m m j^ fs m :l "D IP ©icj^ Palaont N T.Vol IVPt 11 = VolVin. i'i;"\'i'i().M-.i,i.ii).v. ( ii'iuTic 1 llustfjilums Plate LXXXr '^ J PhiAsi-iuli. E.Lmiiions de! PLATE LXXXIT. (Figures 1-K, 10-13, 18, 22, 23, 2.'j, 2(i Ijy G. IJ. Simpson ; 7, n liy E. IOmmiin.s ; s, :i, 14-17, l!i-:i, -.'7 38 liv U. I'. Win 1 1 iki.k. Genus CCELOSPIRA. Hall. Page l:iO. CcELOSPIRA HEMISPHERICA, SoWOlliy. Figs. 1, 2. Exteriors of two pedicle-valves ; showing the contour, character of pli(^ation and concentric strise. Figs. 3, 4. Exteriors of brachial valves. Clinton group. Western New Yrn-k. CcELOSPIRA PLICATULA, Hull. See Plate 52. Fig. f). The interior of a portion of the bi-achial valve ; showing the divided hinge-plate and median ridge. X 2. Clinton group. Wayne county. New York. Genus ATRYPINA, gen. nov. Page IBl. Atrypina Clintoni, sp. IIOV. See Plate 53. Fig. 6. The exterior of a pedicle-valve. X 2, Clinton group. Fi'om a boulder : Western, New York. Genus ANABAIA, Clarke. Page Ul. Anabala. Paraia, Claikf. Fig. 7. An internal cast of the brachial valve ; showing the impression of the cardinal process and the marginal elevation of the median fold. Middle Silurian. liio TroiiMtris. Brazil. Genus VITULINA, Hall. Page l.is. VlTULINA PUSTULOSA, Hull. Fig. 8. The exterior of a pedicle-valve of an average sjiecimen. Fig. 9. The exterior of a brachial valve. Fig. 10. Ventral side of an internal cast; showing the impressions of the teeth, adilui-tor and diiluctor muscles. X 2. Hamilton shales. Western New York- Fig. 11. Ventral view of a preparation ; .showing three volutions of the spiral cone whicli is directed towai'it the lateral margin of the shell. Hamilton shales. Alden, New York. Figs. 12, 13. Interiors of brachial valves ; showing the cardinal process and low crural plates. Mid perlicle-vaho ; showing the muscular impressions. X 2. Figs. 22, 23. Interiors of l.)rachial valves ; showing cardinal process and muscular impressions. X 2. Fig. 24. Interior of a brachial valve ; showing the cardinal area and proce.ss, crural plates and muscular scars. X 3. Fig. 2,'). An enlargement of the external surface; showing the radiating rows of elongate pustules. Hamilton shales. Prom various Jjealities in Western New York. Genus TROPIDOLEPTUS, Hall. Page :102. Tropidoleptl's CARINATUS, C'oillild. Fig. 26. The pedicle-valve of a very young shell ; showing the acuminate <-ardinal extremities and the coarse, simple and sharp plication. X 3. Hamilton groujj. Caiiandaigua Lake, New i'ork. Fig. 27. An enlargement of an interior layer of the shell ; showing punctae. Fig. 28. A horizontal section of the shell substance ; showing the radial rows of obliipic ttdiidcs jienetrat- ing the fibrous shell substance. Fig. 29. Cardinal view of the umbonal portion of the valves; showing the open delthyrium, the great de- velojunenl of the chilidium, and the cardinal area X 3. Figs. 30-32. Ventral, profile and dorsal views of an a\i!rage example ; showing the characters of the ex- terior. Fig. 33 An internal cast of a large pedicle-valve ; showing the impre.ssion of the area, pedicle-cavity, teeth and dental ridges. Fig. 34. An internal cast of a brachial ^■alve ; showing the impression of the cai'dinal process and crenu- lated dental sockets. Fig. 35. The interior of a pedicle-xiilve ; showing the cardinal area, open delthyrium and the prominent crenulated teeth. Fig. 36. The interior of a brachial valve; showing the cai'dinal process, crenulated dental sockets and median sejitum. Hanulton groiiu. Prma rarioim localities in the argillaceous and arenaceous shales of Central and Western Neio York. Tkopidoleptus occidens, Hall. Figs. 37, 38. Dorsal and central views of the original specimen of the species. Hamilton grouji. hnra ('itij, Iowa. w ii:^ ^ 'G :ii :i Tf Is- dxi-tN, ( M»lH*rU' lllustl.llMIIlS Paleeonl.N Y.Vol.IVPt ii = Vol.Vin. W ./ /" 11 ^i •^JliV'* 22 H rffij-jrf,':,;'^fi 31 COF-LOSPlHlD/r. TEBEBRAT£LL1DA;. £6 c &^i^5^ :4> X; „rrr ^P? Pl^te I.XXXII ;^' :-,Yv^ **-»^ ^^ 5^/A^ r ■.J.*-* #'^.N _ .-' r "TV, ':^ ,t\, . /.' -ii_ R.F.'.ffliiiiiaia del PhiLAsLliih. PLATE LXXXIII. (Figures 1-8, 12, 13, 26-41 by G. B. Simpson ; 9 by C. K. Bkecher ; In, n by It. 1'. Wimtfikld ; ll-23by K Khmuk« ( Genus EICHWALDIA, Billings. Piise 307. ElCIIW.\LI)I.\ SCHIKIGONALI.-^, Billill';-.--. Fig. 1. Doi'.sal view (if conjoineil valves, till' l)nicliiiil valve being so broken jis to expose the median septum. Figs. 2-4. Doi-sal, cardinal and front views ; showing the .smooth surface, and the " bare spot," or ped- icle aperture. These figures are from the oHginal specimens of the species. Black River limestone. Pauijuette's Rapids, Canada. ElCHW.VLDI.V CO.NCMXNA, Hall. Fig. 5. Dorsal view of tin- original specimen. Niagara gi-oup. Perry county, Teime-ssee. ElCHWALDIA GIBBOSA, Hall. Fig. (5. Dorsal view of the original specimen. Fig. 7. An enlargement of the external surface, showing the pimctic. X S. Niagara group. Perry county, Teimessee. ElCHWALDIA RETICULATA, Hall. Fig. 8. The interior of the umbonal portion of the pedicle-valve ; showing the ti-iangular intei-nal apical plate. X 2. Fig. 9. Dor.sal view of the youngest specimen oliserve J. X 10. (After Beechek and C'i.akkk, Memoira N. Y. State Museum, Vol. 1, No. 1.) Figs. 10, 11. Cardinal and dorsal views of an average specimen; showing the pedicle-aperture and the chai'acter of the external surface. X 2. Fig. 12. The interior of the pedicle-valve ; showing the open delthjrium and the linear ridges on the lat- eral margins. X 2. Fig. 13. The interior of a bi'achial valve ; .showing the cardinal j^rocess and the marginal gi'ooves for the reception of the ridges on the opposite valve. X 2. Niagara gi-oup. Waldron, Indiana. Genus AULACORHYNCHUS, Dittmak. Page 311. AuLACORHYNCHUS MILLEPUNCTATUS, Meek ami Wortlien. Fig. 14. The exteidoi' of a pedicle-valve, from which a portion of the shell has been exfoliated, showngthe inner sui-face of the triangular muscular platform. Fig. 15. A very large brachial valve; showing tlje outline and sui-face characters. Coal Measures. Croo/ced Creek, lllhwis. Genus TRIPLEGIA, Hall. Part 1, page 269. Triplegia Niagarensis, .>]). nov. Figs. 16-19. Cardinal, profile, obliiiue cardinal and front views of an internal cast; .showing the sharply defined median fold and sinus on brachial and pedicle-valves respectively, the marginal plica- tion, and the cavity left by the cai-dinal prt cess. Fig. 20. View of the articulating processes, taken from a gutta-percha impression of the same specimen ; showing the bifurcated cardinal process and the teeth. X ^■ Niagara dolomites. Near Milwaukee, Wisconsin. PLATE LXXXIIl— Contiimed. Genus TREMATOSPIRA, Hall. Page 124. Trematospira Tennesseensis, sp. uov. FifTs 21-23. Dorsal, j>rofile and ventral views of the .shell ; showing the convexity of the valves and the coarse plication. Lower Helderberg grou]). Ptrry aniiitij, Tennessee. Subgenus HOMCEOSPIRA, s.-gen. nov. Page ll>. See Pliitc .")(). HOMCEO.SPIRA APRINIFORMIS, Hall. Figs. 24, 2,^. Dorsal and profile views ; showing the contour and character of plication. Niagara group. Cumberland, Maryland. Genus EUMETRIA, Hall. Page 115. See Plate 5L EuMETRIA VeRNEUILIANA, Hilll. Figs. 26, 27. Dorsal and profile views of a large, sharply costate individual. St. Louis limestone, l^pergen Hill, Indiana. Genus PTYCHOSPIRA, gen. nov. Page 112. Set- Plate .'>(). Ptychospira sex-plicata, White uikI Whitiield. Fig. 28. The exterior of a pedicle-valve of the type specimen. Kinderhook group. Burlington, Itnea. Genus ZYGOSPIRA, Hall. Page 151. See Plate 54. ZyGOSPIRA PUTILLA, S\). IIOV. Figs. 29, 30. Dorsal and ventral views of a typical examjile. Hudson River group. Pike county, Missouri. Genus RHYNCHOTREMA. Hall. Page 182. See Plate 5G. Rhynchotrema c^pax, Coiinid. Fig. 31. Cai'dinal view of the pedicle-valve shown on plate 56, tig. 17 ; .showing the excavation of the pedicle-pa,ssage and its opening through the substance of the shell. X 3. Hudson River group. Iron Mid^/e, Wisconsin. Genus GLASSIA, Davidson. Page 1.^2. GlASSIA RoMINGERI, tfj). uov. Fig. 32. A preparation showing the introverted coils and the direction of the loop. X 3. Figs. 33-35. Dorsal, profile and venti'al views of a specimen, showing the smooth exterior and bilobed anterior margins of the valves. X 2. Trenton limestone. In a drift boulder, "near Ann Arbor, Michigan. m 31 ^ (B 211 2 © :i> © 23 ^ Palaeont.N r.Vol.rvPt ii- VoI.VIII. Mrsci:i.i,Axi:ors (■IMII'IH- Illusll-.ilioilS :j^ 3 B Plate LXXX31I ^ «N**" fe-. 1 ^a^ ^r. # J # ^ i B Siitipson del PrilAs'.lisa. PLATE LXXXIII— Conlinueil. Genus HALLINA, N. H. Winchell and Schuciiekt. Pilgo 15(1. Hallina Saffordi, N. H. Winclicll and Sclnuliert. Fig-s. 36-38. Dorsal, pi-otile and ventral v-iews of a tyijical exami)ie. X ■'). Trenton limestone. Lebmum, Ttniwsste. Genus ATHYRIS, McCoy. Pago Si. See Plate.s 45-47. Athyris incrassata, Hall. Fig. 39. The interior of a pedicle-valve (jf average size ; showing the pedicle, adductor and diduclor im- pressions, and the thickened shell-margins. Warsaw limestone. Desmoines Rioei; Iowa. Genus STRICKLANDINIA, Billings. Page 249. See Plate 73. Stricklandinia Chai'mani. sp. nov. (Compare Billings, Pala^izoic Fos.sils, vol. ii, l)t. i, pi. vii, Hg. 3). Fig, 40. An incomplete internal cast of the pedicle-valve ; showing the impre.ssion left by the highly de- veloped cardinal area. Niagara group. Hamilton, Ontario. Subgenus CRANiENA, s,aEN. nov. Page 2y7. (.;KAN.i;NA loWENSIS, Calvill. Fig. 41. A preparation showing the structure of the loop, the a-scending branches being but partially re- tained X 2. Middle Devonian. Fayette, lima. PLATE LXXXIV. (Figures !-♦, 14-1!1. 23-25, 29, 3r,, 37, 41-46 by G. B. Simpson ; .V13, 20-22, 30-36, 38-40 liy E, KMMONS ; 2.i-28 copies.) Protorthis, sp. ? Fig-. 1. The interior of a pedicle-valve ; showing' the small spondyliinn made by the vinion of the short dental plates, the low median ridge and the muscular impressions X 2. FifT. 2. A portion of the same specimen drawn so as to .show nioi'o clearly the converg-ence of the fonu of tin- shell, the .short, straight hinge, and the conspicuous muscular scars. Fig. 4. The interior of a pedicle-valve ; showing- the cardinal area, open dcltliyiiini], niusi-ular scar and short meilian septum. Figs. 5-7. Ventral, doi-sal and canlinal views (thi' last wilh the pi'dicle-valve above) of an internal cast; showing the form of the mu.--cular imjiressions, the median septimi in each valve, and the ele- vation of the cardinal area, X 2. Tin' external surface of the shell is unknown. Niagara dolomites. Near MUwaiikrc. Wisconsin. The genei'ic chai-acters of this shell are so distinctly unlike tho.se of any exi.sting genus that it is here proposed to distinguish it liy the new lerni OrthcitmiI'ia. Orthi.s ? GLYPTA (C<>iHi):irc 0. Loveni, Lin(l.->tioiii), sp. iiov. Fig. H. A partial internal cast of the pediidi!-valve ; showing the outline of the .shell, its surface ornamenta- tion and the form of the muscular impression. Fig. !). A similarly preserved shell with but a sing-le .sej'ies of radial jilications and showing tho pecidiar reticulating surface sculptiu-e. X 2. Niagara dolomites. Near Milwaukee, IViicoiiMn. Orthis flabellites, Hall, var. Sjxniia, var. iiox-. See plates 5 and 20. Fig. 1(1. An internal cast of a pedicle-valve, having the expression of 0. JlaheUite.t, but with scarcely more than one-half of the number of jilications itsual in this species. Niagara dolomites. Near Milwaukee. Wiseunsin. Stropheodonta (Pholidostrophia) nacrea, Hall. See Plate 1."). Fig. 11. The interior of a brachial valve ; showing the muscular scars and vascular sinuses. X 2. Hamilton shales. Livonia Salt iihaft, Neio York. Stropheodonta (Brachypuion) profunda, Hall. See Plates 12 and ■20. Fig. 12. A piu'tlon of an internal cast of a large pedicle-valve ; showing the cardinal area, the partial filling of the delthyrium, the .'imall adductor and large diductor impressions. Niagara dolomites. Near MilvMukee, Wiseon.nn. Stropheodonta (Douvillina) Cayuta, Hall. See Plate 15. Fig. 13. The interior of a pedicle-valve ; .showing the elevation of the muscular scar into a well deKned platform ; also the abrasion of the cardinal area by the teeth of the opposite valve. Chemimg group. Steuben county. New York. Stropheodonta (Brachyprion) corruoata, Hall. See Plate 15. Fig. 14. A portion of an internal cast of the pedicle-valve enlarged to show the crenulations of the hinge- plate, near the beak. X 2. Clinton group. Rochester, New York. m ni^osjii©!? ©11)^ Palffiont N Y.Vol rVPtii'VolVni- MiscKi.i.ANKois ( '»ni».'l'i(" lllustr.'ilitHis Plato LXXXN^ ¥r !t. — ja&n V '^-tllij**,^' G.B.Simpson del i'r.ii.AsUiui. I'l.VTK I.XXXIV— C'oiitiimed. StUOI'IIOMCLLA COSTATULA, S)). MOV. Fig^s. 1"), It'i. Dorsal and pi'dtile views nt' tlie slicU ; .sliinving' tlie reveitteil convfxily nf tlii- vulvex iiml tin- sharply rouiuled, irref^iilarly diclidtoniizing' |. ligations. Niaffara tfi'(Hi|>. £,(iiii.sinllt', Kentiuky. Had'inesquina alteknata. Coiintd. Fig*. 17, 18. Enlargements of unibonal portions of internal rast.s of the peiliile-valve. to»how the Kllin|{' of the pedicle-passage. In tig. 18, which represents the older shell, this tillini; is wen to be the smaller and is constricted at its liasi;, evincing thus the tendency of the shell to close thin pax- sage at its inner extremity. X 3. Hudson River grouji. lirratic blockx in xcestent Nmo York. PrODUCTELLA NAVICELLA, Hall. See Plate 17. Fig-. 19. A .small pedicle-valve preserving the spines in a perfect condition and showing (he convergent- of the cardinal spines. X 5. Hamilton group. Caiiandaigua Lake, New York. Strophalo.sia Rockfordkxsi.s, sp. IIOV. See Plate 17a. Figs. 20, 21, 22. Ventral, dorsal and cardinal views of a specimen ; showing the general external characters and the umbonal cicatrix Upper Devonian. liarkfard, Iowa. Plectambonites prodocta, sp. IIOV. Figs. 23, 24, 2.^. Cardinal, jirohle and front views of an internal cast of a pedicle-valve ; showing the form of the teeth and muscular impre.ssions, the short hinge and the gi-eatiy pi-oduced anterior margin. Niagara dolomites. Yellow l^prings, <)hU>. Hyattef.la conoesta, Hull. See Plate 40. Figs 2(i-28. Doi'sal, front ami profile views of one of the original specimens (Palicontology of New York, vol. II. pi. xxiii, tigs. 1, f, g, i). Clinton group. Monroe county, New York. Spirifer l.en'is. Hall. See Plate 38. Fig. 29. A portion of the cardinal region enlai-ged to show the peculiar structure of the deltarium, which bears a circular perforation with elevated margins, anil is surrounded by an elongate, smooth area, at the edges of which the growth lines are sharply interrupted. X 3. Chemung gi-oup. Near Ithaca, New York. .•^E.MINUI.A .'iUBQUADRATA. Hall. See Plate 47. Figs. 80, 31 . Dorsal and profile views of the original specimen. Kaskasia limestone. Chester, Illinoli. Cliotiiyris ROYSSII, L6veille. Fig. 32. The interior of a brachial valve ; showing the form of the hinge-plate. Coal Measures. Tournal, Belgium. Athyris concextrica, von Biicli. Fig. 33. An enlargement of the hinge-plate ; showing its form, tripartite division, and apical perforation. Middle Devonian. Ferques, Brittany. PLATE LXXXIV— Continued. TORYNIFEK, gen. nov. ToHYiMFEU CKITICUS, !i[). IIOV. Fig's. 34. o5. A iVag^inent of a ptiiicle-valve, with well fietined cai'dinal area, iu'dinineiit teeth, ccnvergent (iental lamella' foi'miiiu' a liistinct .'spondyliuni smijmi'tetl liy a nieUian septum. Nothing' further is known of this peouliar shell. Its general relations are probably less athyroid than orthoid. X 2. Though hut this fragment is known, it beai-s the critical structure which separates it fiom othei- g'enera, antl may heiKre a< well receive a distinctive desigfnation now as hereafter, when its other characters shall have been determined. St. Louis g'roup. La Rue, Kentucky. Spirifeu (cf.) niETU.s, White and WliitHcld. See Plate 4li. Fig:. 30. A pedicle-valve, .showing the compound spines at the concentric growth-lines. Fig-. 37. A portion of the same specimen enlarg-ed, to show more distinctly the character of these spines. Waverly g'l'oup. Hii-lifiuld, Ohio. NUCLEOSPIRA COXCINNA, Hall. See Plate 48. Fig. 38. Posterior cardinal view of the brachial valve ; .showing: the e'evation and curvature of the cardinal process. X 3. Hamilton g'rou]). Clarke (•ounty, Indiana NUCLEOSPIRA VENTRICOSA, Hall. See Plate 4S. Fig. 39. View of the cardinal process. X 13. Fig. 40. The same specimen projected backward to show the elevation of the ci'ural bases. Lower Helderberg- group. SchohaHe, New York. Cyktina XEOGENES, SJ). IIOV. Fig. 41. The pedicle-valve of a very tran.sverse SpiRiFERiNA-like species, broken so as to siiow the median septum suppoi'ting convergent dental plates. Chert of the Burlington limestone. Burlingtan, Iowa. It is important to observe that this shell, with the external a.spect of Spihiferlna and the interior structure of Cystina, is the palieozoic precursor of numerous Triassic species passing under the name of Spiui1''ERIna, though assiu'edly not of that genus. Camarella Volborthi, Biliiiig.s. See Plate . Fig. 4'J. A fragment of the umbonal portion of the shell, showing the spondylium of the pedicle-valve and the lateral walls of that of the brachial \'alve. X 3. Black River limestone. Pauquctte's Rapids, Catiada. .\na.strophia Verneuili. Hall. See Plate . Fig. 43. Carilinal view of a normal example, represented \vith the i)edicle-valve above. Fig. 44. The interior of a brachial valve ; showing the spondylium and adductor scars. Lower Helderberg group. Albany county, Ntnv York. Camarophoria ringens, Swallow. Fig. 4.1. C'ai'dinal view of an internal cast of conjoined valves, retaining the tine radial surface striae. Burlington limestone. Loui.s-iana, jMis.smin. Barr.\ndella ventricosa, Hall. See Plate . Fig. 4ti An internal cast of a pedicle-valve ; showing divergent muscular or vascular riilges. Niagara dolomites. tSouthem Wiscansin. QH Natural history of New York 105 N'^3 V.30 BioMed PLEASE DO NOT REMOVE CARDS OR SLIPS FROM THIS POCKET UNIVERSITY OF TORONTO LIBRARY