Diy ar PERN a Me i DEPARTMENT OF THE INTERIOR MONOGRAPHS OF THE UNITED STATES GEOLOGICAL SURVEY ete WOU IMEI > OIG IN WASHINGTON GOVERNMENT PRINTING OFFICE 1903 as nu) ial NH UNITED STATES GEOLOGICAL SURVEY CHARLES D. WALCOTT, DIRECTOR PSEUDOCERATITES OF THE CRETACEOUS BY J Jl Jalsa Olt, del se db Edited by T. W. STANTON WASHINGTON ,GOVERNMENT PRINTING OFFICE 1908 CONTENTS. IDO [DROINGE, scan cncacasa cannes con ca ssoneseoossEdoesHt Sooocn ands oseauanpsconsacenesecs @lassified! list of families, genera, and species...-....----------------+--------2------------=- TA Or INOMMAOIE ood secon coccesodbc Susans dosboodansndoods sypess dnecce booeaooSsSSscsDEes (Gemenill RAMOS . sachs nck lh Sacssccoossecsosgnqetuadoucagsanabsccousesoassceesoessessoscssee SAO TEMO CSO NMOS son coca cs55 donooeaoseo esos asonnogesedcc oss docesuscadescsdosoesoEsons WirranmntnGhy = bo oonoGebee tes soou sb codes eqEUeEEe bec cosananasdSuSHemErececodcodosees bouc IMIG HSSOWACTCHS — cing osc basa dnagesacéeconseaeese punce=ooesUsSandecosonoseeassossas TRO MAS ROR woe Ss Ne Se ee Ree ee a ome a eCouE eo tansacenAaneoseacceecnoa bee Teeamcloasonlks ol. bo. oo seods psocbosousosseaducuessesouskeseosaouououbeceososonSES IMR OIG ES Sees eobosueocu cosResebaaanoeAaeaoebsaesransccoseMebocosEsbencaredcsdas SromcmaaliseiGles 5-6 Us osonoeaoosduosnouseeouese esos cnboan se baaboEaccccosnocsoaenass TaN CETAINORD ..5 os dn At spscoecdosobacdopeesdsansoueosns on gsscocan sense sascoscs OlorlloyaoesmnGbe ss ocddu odadaasocnous seeeoees ooo sodas bacesc dousuccesasagsasocasces CWsimOeenGl = ocessoe Sesudaosgece de cou scdeonssadssassoososeoosesccsosunesoEadasuass VIET TCIM COTATLG AMIR oie cate eerene tay eo 3 ns 3 MAIER cy etree, Seater en Wearmicili@enmndks «55 dceedkscocso ccedodadeaesoseeacdedconodess SeseneseecnccoscbasEns WMieti@n@eoreeennGee. jo -coe oboe ebscceceanousceudnosessacooueeseooenpancSoescosssescss WIGINANC ED colsckoodsbe basse coceodsessouSdopes nob sacs na soneeedououooeuaoereaccndacs TPulkolnginG es —- eoasdece secon sudeeos sopesSsannasneocas seco sbecopseeesoccasssnss ses Tkaaermnni@apnOkO. - Sos soosec ace cousee nao sSoseuu sas Ronneacotocsonseseceuccensases peas IDeA TANCHD — Soe ags seem ses -eo-b ooo ese eseSEEe Soo SE aaeSESe sce e0soSor oe 0sa5c0c WWeyeemmnGawnin6es ~5-oosecascousenanausssueeermdauocceebes season udocSegsemsassadcose INO ONy censososssoseconesee 5 soosconee sec aes ace sco seE SEES Sesees Soe besa oSuosnSoodascs DIGGS cgaasnkhcs Saab bsocbecuscaooe posolaasas nedasoecnesabosccdaooecEcrpacmeceaSosasoHedas Ike ossbesKaece J conc acbudeco suo benedoouadS co SpaaSunomasogucospeesaoSSodcooEstonoasdacess 5 Uo i it he ase ipa IU Sul RAE O LN Se Puiate 1. Figs. 1-3. Mojsisovicsia durfeldi Steinmann aoe 4-9. Buchiceras bilobatum Hyatt | oA 10-14. Roemeroceras syriaciforme | EPS ae 2 WAN ae Re Dee ELS NamerED & = 15. Roemeroceras attenuatum (Hyatt) II. Figs. 1-3. Roemeroceras gabbi Hyatt 4=GueRoemerocerasisubplanuma Ely atts aoe eee eesti esse elaine eel 256 7-11. Paratissotia serrata (Hyatt) III. Figs. 1-6. Paratissotia regularis Hyatt 55 . AB, Soatmeslizensslematsse, (Comme) se IV. Figs. 1,2. Sphenodiscus pleurisepta (Conrad) ..----.------------------------------ 260 V. Figs. 1-3. Sphenodiscus pleurisepta (Conrad) : 262 4. Sphenodiscus stantoni Hyatt eae ast alae ot aaa ar ras VI. Figs. 1,2. Sphenodiscus lobatus (Tuomey) 3,4. Sphenodiscus beecheri Hyatt 264 SB, Carhemediigona simian ieiyeine 9 Pe i 6. Sphenodiscus pleurisepta (Conrad) VII. Figs. 1,2. Sphenodiscus lobatus (Tuomey) -.----------------------+---+++----------- 266 VIII. Figs. 1, 2. Sphenodiscus lenticularis (Owen) \ an 3-7. Sphenodiscus lenticuiaris var. splendens Hyatt [RSs Gok ec 5 game as i IX. Figs. 1-6. Sphenodiscus lenticularis (Owen) 7-9: Sphenodiscus lenticularis var. mississippiensis Hyatt) 270 10. Sphenodiscus beecheri Hyatt ’ 11-13. Sphenodiscus lobatus (Tuomey ) X. Figs. 1-4. Coilopoceras novimexicanum Hyatt) ee 5-21. Coilopoceras colleti Hyatt GeV EN ree REET AMR Te ee ze XI. Figs. 1. Coilopoceras colleti Hyatt 2-6a. Eulophoceras natalense Hyatt = /-------------------------------------- 274 7-24. Metoicoceras swalloyi (Shumard) XII. Figs. 1-3. Coilopoceras springeri Hyatt 4-6. Aconeceras nisum (d?Orbigny) ( . Coilopoceras grossouvrei Hyatt{ 7 BIS 8. Sphenodiscus konincki Hyatt XIII. Figs. 1,2. Metoicoceras swallovi er | Peaevie eacte nel Ae) Cea: hs oe 3-5. Metoicoceras whitei Hyatt 8 PLATE XIV. XV. XVII. SOWIOUL XIX. XXII. XXII. XXIV. XV. XOXV I XXVIT. XXVIII. Figs. 1-10. 11-14. . Metoicoceras whitei Hyatt Figs. 1-5 6-13 Figs. 1 2-6 Figs. 1-5 6-10 Figs. 1-6 7-9 Figs. 1-5 6-8 Figs. 1-4 5-9 Figs. 1-4 5-7 8 Figs. 1,2 3-14 15-17 Figs. 1-6 . Engonoceras serpentinum (Cragin) \ . Engonoceras subjectum as . Metengonoceras inscriptum Hyatt/ . Placenticeras syrtale (Morton) ILLUSTRATIONS. Metoicoceras whitei Hyatt Metoicoceras acceleratum Hyatt . Vascoceras hartti Hyatt . Metoicoceras swalloyi (Shumard) . Metoicoceras gibbosum Hyatt . Metoicoceras kanabense Hyatt }.-----.---- . Heinzia matura Hyatt . Heinzia provincialis (d’Orbigny) . Heinzia provincialis (d’Orbigny) . Knemiceras syriacum (von Buch) . Knemiceras compressum Hyatt 4, Knemiceras compressum var. subcompressum . Knemiceras compressum Hyatt . Knemiceras compressum var. subcompressum 5. Subpulchellia castellanensis Hyatt . Nicklesia dumasiana Hyatt 2. Pulchellia compressissima (d’Orbigny) p-- ---- . Knemiceras attenuatum (Hyatt) . Protengonoceras gabbi (Bohm) J . Knemiceras gabbi Hyatt . Engonoceras belviderense (Cragin) /--------- . Protengonoceras planum Hyatt . Engonoceras uddeni (Cragin) . Engonoceras serpentinum (Cragin) ¢.--------- 7. Engonoceras retardum Hyatt 3. Engonoceras pierdenale (von Buch) . Engonoceras pierdenale var. commune oa . Engonoceras subjectum Hyatt . Engonoceras gibbosum Hyatt . Engonoceras gibbosum Hyatt, . Engonoceras stolleyi Bohm S07 . Engonoceras stolleyi Bohm \ . Engonoceras complicatum Hyatt! Teo a . Neolobites choffati Hyatt \ . Metengonoceras inscriptum Flyatt . Metengonoceras ambiguum Hyatt;.---------- . Metengonoceras acutum Hyatt . Metengonoceras acutum Hyatt . Placenticeras syrtale (Morton) . Metengonoceras dumbli (Cragin) [--------------------------------- 284 286 290 306 308 PrADE) XEXEX: NOLO NNT: NAT. SORT. ROXODV. DO, O: QE MXXVIL. XSOOVILL: XXX VIL. XOXEXTX, XL. X LI. XLII. MLITI. XLIV. ELV. XLVI. XLVII. a ™ 77) oq” GQ" my eal oa nfo} i? JQ” = aq" a ies = eras 3. Placenticeras sancarlosense Hyatt 3. Placenticeras planum Hyatt 1,2. Placenticeras intercalare Meek . Placenticeras intercalare Meek 2. Placenticeras whitfieldi Hyatt ILLUSTRATIONS. . Placenticeras guadalupze (Roemer) . Placenticeras sancarlosense Hyatt, fi vconseesons eee Placenticeras sancarlosense var. pseudosyrtale Hyatt - . Placenticeras newberryi Hyatt . Placenticeras sancarlosense var. pseudosyrtale Hyatt) . Placenticeras planum Hyatt J . Placenticeras intercalare Meek . Placenticeras intercalare Meek } . Placenticeras intercalare var. costatum Hyatt! ~~~" . Placenticeras intercalare var. costatum Hyatt, a . Placenticeras placenta (DeKay ) . Placenticeras placenta (DeKay ) \ . Placenticeras stantoni var. bolli Hyatt) ~~ . Placenticeras stantoni var. bolli Hyatt.-..-........- 2. Placenticeras stantoni var. bolli Hyatt..-..--.....-- . Placenticeras stantoni var. bolli Hyatt . Placenticeras pseudoplacenta Hyatt 3. Placenticeras pseudoplacenta Hyatt.......--.-----.- 2. Placenticeras pseudoplacenta var. occidentale oa . Placenticeras whitfieldi Hyatt . Placenticeras whitfieldi Hyatt 5. Placenticeras whitfieldi yar. tuberculatum Hyatt --- 6-8, . Placenticeras spillmani Hyatt 346 Neer oa! is ss ag a ie EDITOR’S PREFACE. Soon after Professor Hyatt’s lamented death, January 15, 1902, it was the writer’s sad duty, as a representative of the United States Geo- ological Survey, to examine all the paleontological collections and manu- scripts in Professor Hyatt’s house in Cambridge, in order to take possession of those belonging to the Survey. The manuscript of the present volume was on his desk and. contains the results of his last work, in which he was actively engaged on the day of his death. Fortunately it was almost ready for the printer, and although the careful reading of the manuscript to determine the author’s exact meaning and intentions has consumed con- siderable time, the changes, either in arrangement or in wording, and the additions that have been found necessary are very few indeed. These changes are all indicated in their proper places by footnotes or bracketed statements signed by the editor’s initials, except the unimportant verbal b) change of “‘Cretacic” to “Cretaceous,” made for the sake of conformity with Geological Survey usage. In his recent writings Professor Hyatt consistently followed the International Geological Congress rule of ending names of all periods and systems with ‘‘ic.” The preparation of this work occupied a large part of Professor fd Hyatt’s time for several years. As early as 1897 a manuscript with the same title was submitted to the Director of the United States Geological Survey for publication, and soon afterwards the preparation of the illustra- tions was begun. A copy of this original manuscript now in my hands shows many important differences in arrangement, classification, and nomenclature from the later manuscript, indicating that it had been thoroughly revised and recast in connection with a restudy of the fossils. Although there are some minor inconsistencies, and there would doubt- u 12 EDITOR’S PREFACE. less have been some other changes and additions if the author had lived to see the work through the press, it is believed that as now published it fairly presents his latest views. ‘The illustrations were all made under Pro- fessor Hyatt’s supervision, except a few, which were definitely selected and indicated by him, and most of which are copies of published figures. He had also mounted the figures on the first twenty plates and had written the descriptions of nineteen of the plates. The other figures were nearly all labeled with specific names. ‘The manuscript was in two packages, one of which began with the ‘‘General remarks,” followed by Pulchelliidee, Knemi- ceratidee, Engonoceratidee, and Placenticeratidee, which is nearly the arrangement of the original manuscript of 1897, while the second package began with Mojsisovicsiidee and ended with Coilopoceratidee. The plates arranged by the author contain all the illustrations except the Placenticer- atidze and a part of the Engonoceratide. By transferring the introductory “General remarks” from one package to the other and then uniting the two packages the descriptions fell into practically the same arrangement that was adopted for the figures, and which evidently represented the author’s latest views as to their relationships. The assignment of the fami- lies to higher groups was not fully carried out by Professor Hyatt, and it is thought best not to attempt to complete it, in view of the fact that his opinions as to the definition and limits of the different superfamilies evi- dently were much modified, though never formulated, after the publication of his chapter on Cephalopoda in Zittel’s Text-book of Paleontology. In that work he divides the Ammonoidea into several suborders, and between these and the families there is another unnamed category of groups, which may be called superfamilies, such as Mammitida, Cosmoceratida, ete, Part of the Pseudoceratite families are there referred to Mammitida, part to Placenticeratida, the Pulchelliidze were accidentally omitted, and other families were not there described. In the present paper a list of the fami- lies belonging to the Mammitida is given, but beyond that group the clas- sification is doubtful. In connection with the description of Vascoceras, Cosmoceratida is mentioned in such a way that the reference of the genus to that group may be inferred, and later in the manuscript the heading Mantelliceratida is inserted, but there is nothing to warrant the assumption EDITOR’S PREFACE. 13 that the latter term was intended to include Heinziidee, Pulchelliidee, Knemi- ceratidze, Engonoceratidze, and Placenticeratidee. In the published work above referred to, the two families last named are united with Spheno- discidze to form the Placenticeratida, but with the removal of Sphenodis- cid to Mammitida it seems probable that the superfamily Placenticeratida was abandoned. The multiplication of families, genera, and species will be understood by all who are acquainted with Professor Hyatt’s habit of attempting to express in the terminology every important fact observed in the course of his investigations. In characteristic fashion the author plunges into the midst of his subject, beginning his introduction with a discussion of the sutural details of Jurassic ammonites, not tarrying even to define the title of the paper or to make a formal statement of the problems involved. In a footnote on page 546 of Zittel’s Text-book, where he first used the term Pseudocer- atites, he states that it “is a descriptive expression for the Placenticeratida and Tissotidze of the Cretaceous, which are morphic equivalents of some Triassic genera of the Discocampyli as regards both suture and shell form. Their origin is traceable, however, to different groups of the Pachycampyli, a suborder which appears to have been initiated in the Jura along with the Leptocampyli. It is, therefore, improbable that the Pseudoceratites were directly connected with the Triassic Discocampyli.” In a letter written December 26, 1901, in response to an inquiry from the Geological Survey office, he gives the following somewhat more definite statement of the scope and purpose of the present work: “I am at work finishing a ‘Monograph of the Pseudoceratites of the Cretacic.’ This is an artificial group, includ- ing, for convenience of treatment, all the retrogressive genera of the Cre- tacic that have sutures with simple outlines resembling those of Triassic cephalopods, formerly included under the name Ceratites. The known genera described and figured are Buchiceras, Tissotia and its allies, Sphe- nodiscus, Knemiceras, Engonoceras, Placenticeras. The aim of this publi- cation is to give as full treatment as possible of the structure and relations of these genera, in order to determine as far as practicable to what groups among the normal progressive forms they are most nearly related.” 14 EDITOR’S PREFACE. ~ It was Professor Hyatt’s custom, in citing the authority for a species, to give the name of the author who first referred the species to the genus in which it is now retained, instead of citing the one who first proposed the specific name. Thus he wrote Placenticeras placenta Meek, although the form was described as Ammonites placenta by DelKay. This is not in accordance with the rule usually followed by zoologists, and the citations have been changed so that each specific name is followed by the name of the original describer of the species, with the author’s name in parentheses if the generic reference has been changed. When the figured specimens were at the Geological Survey in the hands of the artists, Professor Hyatt requested the writer to examine them carefully and give him notes and comments as to the localities and horizons of the specimens from his own collection and from other museums. The quoted statements concerning various species that appear in the manuscript were extracted from the notes the writer then forwarded to him. The appended tabular statement is intended to show the relative positions of the various marine Cretaceous horizons and formations men- tioned in the text. It does not imply accurate correlation of American and European horizons, the line between Lower and Upper Cretaceous being probably somewhat higher in America than in Europe. The figured specimens that are mentioned in this paper as belonging to Professor Hyatt’s private collection have now become the property of the Museum of Comparative Zoology in Cambridge. The writer has supplied the table of contents, the formal bibliographic list, and the descriptions of the plates after Pl. XIX. T. W. Sranron. CLASSIFIED LIST OF FAMILIES, GENERA, AND SPECIES. In the following list all the groups that are described and all the species that are definitely referred to the genera herein treated are arranged according to Professor Hyatt’s classification as given in the text. The purpose of the list is to bring together in compact form for easy reference the large number of described species that are here referred to new genera. The classification is incomplete and in some cases probably misleading. For example, some of the genera under Cosmoceratida are not assigned to families, and it is very doubtful whether Professor Hyatt intended to place in Mantelliceratida all the families here arranged under that superfamily. It is evident that the author’s published views concerning that group had changed, but unfortunately he had written no revised description. It is therefore necessary to leave the groups classified according to the arrange- ment of the manuscript without inserting the names of any other super- families. Wes Choffaticeras Hyatt. barjonai. meslei. douvillei. Hemitissotia Peron. MAMMITIDA. Mosstsovicsup2. . Mojsisovicsia Steinmann. durfeldi. cazini. batnensis. BUCHICERATID ®. HMAKOV ARE LENG _ tissotizeformis. Buchiceras Hyatt. djelfensis. bilobatum. ceadouroensis. Roemeroceras Hyatt. Plesiotissotia Peron. gabbi. : michaleti. syriaciforme. ADS OTR, attenuatum. subplanum. Tissotia Douvillé. : > tissoti. PSEUDOTISSOTIID &. Subtissotia Hyatt. inflata. Pseudotissotia Peron. intermedia. galliennei. peroni. tunisiensis. africana. 16 PSEUDOCERATITES OF THE CRETACEOUS. Metatissotia Hyatt. fourneli. robini. nodosa. haplophylla. ewaldi. auressensis. slizewiczi. Paratissotia Hyatt. grossouvrel. thomasi. ficheuri. serrata. regularis. INCERTZ SEDIS. Tissotia cossoni. globosa. Heterotissotia Peron. neoceratites. SPHENODISCID &. Indoceras Noetling. baluchistanense. acutodorsatum. Libycoceras Hyatt. ismaele. Sphenodiscus Meek. pleurisepta. lobatus. stantoni. lenticularis. var. splendens. var. mississippiensis. beecheri. konincki. binckhorsti. ubagshi. rutoti. siva. EULOPHOCERATID®. Tegoceras Hyatt. mosense. Lenticeras Gerhardt. andii. Paralenticeras Hyatt. sieversi. Eulophoceras Hyatt. natalense. CorLoPocERATID®. Platylenticeras Hyatt. heteropleurum. pseudograsianum. gevrilianum. Coilopoceras Hyatt. colleti. noyimexicanum. springeri. requienianum. grossouvrei. Aconeceras Hyatt. nisum. COSMOCERATIDA. Vascoceras Choffat. hartti. Tolypeceras Hyatt. marcousanum. Barroisiceras Grossouvre. desmoulinsi. haueri. MANTELLICERATIDA. MaANTELLICERATID A. Metasigaloceras Hyatt. rusticum. Pseudaspidoceras Hyatt. footeanum. conciliatum. cunliffi. crassitesta. euomphalum. deciduum. schliteri. Diadochoceras Hyatt. nodosocostatum. Pedioceras Gerhardt. cundinamarcee. caquesensis. ubaquensis. Douvilleiceras Grossouvre. mammillare. orbignyi. spiniferum. Schluetericeras Hyatt. nodosoides. vielbanci. laubei. michelobense. Sharpeiceras Hyatt. laticlayium. schlueteri. inconstans. Acompsoceras Hyatt. bochumense. essendense. renevieri. CLASSIFIED LIST OF FAMILIES, GENERA, AND SPECIES. Mantelliceras Hyatt. mantelli. couloni. picteti. vicinale. ushas. indianense. domeykanum. MeEToIcocERATID®. Metoicoceras Hyatt. swallovi. gibbosum. whitei. acceleratum. HEINzi1p&. Heinzia Sayn. sayni. corioli. heinzi. hispanica. pulchelliformis. provincialis. matura. ouachensis. Carstenia Hyatt. lindigi. caicedi. subcaicedi. tuberculata. galeata. Gerhardtia Hyatt. galeatoides. galeatus. veleziensis. PULCHELLUD&. Nicklesia Hyatt. moltoi. levyi. nolani. lapparenti. alicantensis. karsteni. lenticulata. didayana. dumasiana. Subpulchellia Hyatt. oeblerti. fouquel. sauvageauli. castellanensis. MON XLIV—03——-2 Pulchellia Uhlig. nicklesi. schlumbergeri. columbiana. selecta. hettneri. changarnieri. kiliani. ouachensis. compressissima. Psilotissotia Hyatt. chalmasi. mariole. defforgesi. reigi. haugi. Lophobolites Hyatt. cotteaui. KNEMICERATID&. Knemiceras Bohm. syriacum. compressum. var. subcompressum, attenuatum. gabbi. uhligi. ENGONOCERATID&. Protengonoceras Hyatt. gabbi. planum. emarginatum. Engonoceras Neumayr. belviderense. uddeni. serpentinum. pierdenale. var. commune. subjectum. gibbosum. stolleyi. complicatum. emarginatum. roemeri. Neolobites Fischer. vibrayeanus. choffati. peroni. Metengonoceras Hyatt. inscriptum. ambiguum. acutum. dumbli. IL? 18 PSEUDOCERATITES OF THE CRETACEOUS. Grayson. Main street. Denison; Paw Paw. Albian, Gault. PLACENTICERATID A. Placenticeras warthi. : memoria-schloenbachi. Placenticeras Meek. depressum. guadalupe. grossouvrei. sancarlosense. incisum. yar. pseudosyrtale. milleri. planum..— schliiteri. newberryi. orbignyanum. syrtale. polyopsis. ea halei. crassatum. intercalare. tamulicum. placenta. pseudorbignyanum. stantoni. : subtilistriatum. var. bolli. Diplacmoceras Hyatt. pseudoplacenta. bidorsatum. var. occidentale. canaliculatum. whitfieldi. var. tuberculatum. spillmani. INCERT# SEDIS. telifer. ? fallax. Styracoceras Hyatt. ebrayi. balduri. Table of horizons mentioned in this work. Upper Missouri. Texas. Gulf border. | New Jersey. Europe. Fox Hills. | Navarro, Eagle Pass. Ripley. Manasquan | Danian. U e Montana en marl). : Fort Pierre. | Taylor, San Carlos. Selma(Rot- | Rancocas 3 ten lime- (Middle 3 stone). marl). Campanian. 3 Monmouth | SenonianjSantonian. S) (Lower Coniacian. H < marl). Si Niobrara. Austin. Eutaw. Matawan Colorado. | (eyeem)). Ss Fort Ben- | Eagle Ford. Turonian. | ton. Dakota. Woodbine. Cenomanian. Buda. | Lower Cretaceous. Edwards. - Washita. Marietta. I Denton. a Fort Worth. o a k k. 2 Preston [Duc Gige a |Kiamitia. | ie) is) Walnut. Paluxy. Abubinyesooo nocd Glenrose. Travis Peak. Fredericksburg [emacs Peak. Aptian. Barrémian. Hauterivian, Valangian, Berriassian. eal PSEUDOCERATITES OF THE CRETACEOUS. By AupHeus Hyatt. GENERAL REMARKS. So far as I have been able to see, either in figures or in specimens, the Ammonitine of the Jura have only one large first lateral lobe, even in highly involute forms, as demonstrated by the admirable researches of Buckman“ upon Hyperlioceras discoidum, subdiscoidum, etc., and the same has been shown by Oppel’s figures’ of Newmayria discus, hochstetteri, and aspidoides, and Quenstedt in-Amm. truelli,“and the similar hollow-keeled forms alsoin New- mayria serrodens (pls. 24, 69), Polyplectus discoides, and capellinus (pl. 53), which have a very deeply divided and double first lateral, and in Newmayria discus (pl. 57) in which there are apparently two or three principal laterals, but in the neanic stage only one bifid first lateral. The Arietidae seem to have two principal saddles owing to the great development of first auxiliary, but this occurs only in the ephebic stage. Aspidoceras and some forms of other genera often have two well-divided principal lateral saddles, but this again occurs through the late division of the primitive lateral. In fact, it may be confidently stated that in the Jura all of the Ammo- nitinze have but one principal lateral saddle throughout the neanic stage, and when, as very rarely occurs, two or three principal laterals are either apparently or actually developed, they occur as purely secondary, or rather, tertiary developmental changes in the ephebic stage. This fact is of importance because of its bearing upon the biology of Ammonitine in the Cretaceous. With regard to these, it may be stated > Pal. Mittheil., pl. 4. ¢Amm. d. schwib. Jura, pls. 24, 69. 20 PSEUDOCERATITES OF THE CRETACEOUS. compared with the Ammonitine of the Jura. All of the forms so far inves- tigated, which have more than one principal lateral saddle and lobe, acquire these characters a stage earlier than the Jurassic species. They appear, as stated above, in the neanic stage and are secondary modifications of the outlines of the primitive first laterals of the nepionic stage. The same law seems to hold in a modified way for the development of an extra number of auxiliary lobes and saddles such as appear in Newmayria, but my materials have not enabled me as yet to follow this out. This statement appears at first sight to be antagonized by that made with reference to the arrested development of the sutures in genera like Protengonoceras, Engonoceras, ete., which have undivided or bifid saddles and lobes only slightly digitated at their extremities. But it will be shown in the generic description of Placenticeras that the arrest of development takes effect in these Pseudoceratites of the Cretaceous only after the three principal lateral saddles and lobes are formed in the neanic stage. Consequently, up to this stage, the development is more complex than im the young of Jurassic species or any others which have only one principal lateral at the sameage. This statement clears up the extraordinary relations of these forms to their apparently more complicated allies of the Jurassic, and accounts also for the apparent discrepancy existing between the highly involute compressed character of the whorls during the neanic stage and the very simple aspect of the lobes and saddles; that such highly involute compressed forms in the Jura, usually combined with the development of highly complex lobes and saddles, has been recorded by me in other papers and by many other writers; consequently, when one meets the Pseudocera- tites of the Cretaceous he is apt to imagine them to be what Barrande has called ‘‘anachronisms,” and difficult problems for the evolutionist. They are unquestionably difficult, but they are no more anachronic than any of the forms usually named as having this paradoxical character. ‘They are simply excellent examples of arrestation of development taking effect locally and upon certain structures. These, if I have rightly understood the researches of my deceased friend, Professor Cope, the most brilliant investigator and profoundest thinker on evolution that America has pro- duced, are good examples of his law of retardation in development, and also excellent examples of the different way in which I look upon the same phenomena. I have never regarded such cases as examples of a tendency GENERAL REMARKS. 21 to retardation of development. A distinction exists between arrestation and retardation in development, which is of great importance. Arrest of development occurs in many ways. It may take effect locally, as upon the sutures, stopping them from developing in complexity of outline beyond a certain measure, and thus retaining a semblance to their own young and apparently reverting to the condition of the same parts in more ancient animals of their own stock. It may take effect upon the whole organism, as in Baculites and other uncoiled forms, apparently causing the entire animal to revert in its characters to a primitive form. There are innumer- able degrees between these two extremes which it is not necessary nor appropriate to mention here. Retardation is distinct from these and of much rarer occurrence. “ The development can not be said to have been retarded in these retrogressive forms, since it begins and for a certain period in the ontogeny progresses in parallel lines with the ancestors of the group, but passes through the modifications more quickly according to the law of tachy- genesis. After this its progress is quite suddenly and decidedly arrested, and the succeeding stages are no longer parallel with those of their ancestral forms. The complexity of the outlines of the lobes and saddles in species of Hngonoceras, for example, does increase even in the later stages; but this increase is very slight, and the result is a retrogressive form that mimics to a certain extent primitive forms among Goniatitinee and Ceratitine. Such examples may, nevertheless, belong to the highly accelerated class, as is shown by the earlier development in these Pseudo- ceratites of the Cretaceous of the three principal saddles that only appear in the ephebic stage of the highly progressive forms among Ammonitinz of the Jura. Retardation of development certainly does not take place in their early stages. Can it be said to take place because they do not subsequently proceed to develop numerous marginal lobes and saddles on the borders of these same lobes and saddles? Retardation of development can mean but one class of phenomena, viz, those cases in which a character appears in the ontogeny of descendants later than the stage at which it appeared in the life of their ancestors. In cases of retrogression such as are noted above, and in all examples of this class with which I am acquainted, the complication of the lobes and «Bioplastology and related branches of biologie research; Proc. Boston Soc. Nat. Hist., Vol. XX VI, p. 79, etc. 22 PSEUDOCERATITES OF THE CRETACEOUS. saddles by the addition of marginals during the later stages of the ontog- eny does not occur; the inexact parallelism is produced by the dropping out of this stage completely, not by its later and later development. Cope, in his great work Origin of the. Fittest, writes as follows:* * * * The acceleration in the assumption of acharacter, progressing more rap- idly than the same in another character, must soon produce, in a type whose stages were once the exact parallel of a permanent lower form, the condition of inexact parallelism. As all the more comprehensive groups present this relation to each other, we are com- pelled to believe that acceleration has been the principle of their successive evolution during the long ages of geologic time. Each type has, however, its day of supremacy and perfection of organism, and a retrogression in these respects has succeeded. This has, no doubt, followed a law the reverse of acceleration, which has been called retardation. By the increasing slowness of the growth of the individuals of a genus, and later and later assumption of the characters of the latter, they would be successively lost. To what power shall we ascribe this acceleration, by which the first begin- nings of structure have accumulated to themselves through the long geologic ages complication and power, till, from the germ that was scarcely born into a sand lance, a human being climbed the complete scale and stood easily the chief of the whole? dina Acceleration signifies addition to the number of those repetitions during the period preceding maturity as compared with the preceding generation, and retarda- tion signifies a reduction of the numbers of such repetitions during the same time.? Thus, from Cope’s point of view, tachygenesis is the law of progression, and retardation is the law of retrogression, and they are both essential parts of his law of acceleration and retardation. These quotations show that we both have the same conception ot the proper use of the word “retardation,” but we differ in the application of it. He applied it to such cases as are described here among Pseudo- ceratites, whereas I regard these as true arrests of development and not as retardations. Retardation is exceedingly rare among Ammonitinze, and as a rule in other parts of the animal kingdom, and the only examples I am able to cite are like those given below in Placenticeras, where the more complex species like whitfieldi, that are obviously descended from species like P. syrtale, have apparently the nodes and ornaments smaller and developing, as a rule, later than in that species, and finally, in extreme forms like those of typical whitfieldi, disappearing altogether. ap. 142. dP. 182. GENERAL REMARKS. 23 As a rule, among Ammonitinz the reverse is the case, and the disap- pearance of characters takes place through the earlier and earlier develop- ment and shorter and shorter life history of each characteristic, or through tachygenesis, as stated and illustrated in many of my papers. Here I have space only for one quotation, which will serve to show my meaning more plainly: Specialization by reduction of parts is evidently included under the head of retardation by Cope; thus in Origin of the Fittest (p. 353), he says that ‘*change of structure during growth is accomplished either by addition of parts (acceleration) or by subtraction of parts (retardation).” So far as my experience goes, in the major number of cases the parts or characters that are undergoing reduction disappear according to the law of tachygenesis. They reappear in the ontogeny at earlier and earlier stages, or exhibit this tendency in the same way as characters of the. progressive class, but their development is not so complete as in ancestral forms. In this sense they can be regarded as retarded or thrown back in their development. There is, however, another way of formulating the expression of this. Instead of regarding this disappearance by retrogressive gradations as due to a tendency opposed to acceleration, is it not a tendency of the same kind? That is to say, do not the parts and characters show a tendency to disappear earlier and earlier, and are they not in most cases at the time of disappearance present only in earlier stages of growth than that in which they originated in ancestral forms? Is not the case of the wisdom teeth exceptional? The frequently extremely late external appearance of these is not accompanied by a later origin of their rudiments in the jaw. Although they may not appear in many cases above the gum until a person is past fifty, is not this real retardation due primarily to the fact that they are deficient in growth power (tending to disappear from disuse, etc.), and secondarily to their internal position? When they cease to be able to break through the gum will they not still continue to develop at the same stage as the other teeth, and will not their rudiments be likely to be present at this early stage long after they have ceased developing into perfect teeth? 4 The whalebone whales are examples of this kind so far as the teeth are concerned, although here the disappearance is correlated with the develop- ment of whalebone from the rugze of the roof of the mouth. Nevertheless the suppression of the teeth in full-grown animals does not take place by later and later development, and the rudiments of the teeth are still present in the early stages. 4 Bioplastology: Proc. Boston Soc. Nat. Hist., Vol. XX VI, note to p. 80. SYSEHMATIC DESCRIPTIONS: MAMMITIDA.* This group in my chapter on Cephalopoda in Zittel’s Text-book con- tained a number of keeled families, in which either the keel was preceded by a median line of tubercules, or, if this stage were omitted, the smooth keel arose upon the venter in forms that were apparently closely allied to the more primitive genera having these tuberculated keels. The Mam- mitida included Mammitidee, Peroniceratidee, Prionotropide, Hystato- ceratidee, Lenticeratidee, and Tissotiide. To these I propose to add now the Mojsisoviesiidee, Buchiceratidee, Pseudotissotiidae, Kulophoceratidee, Sphe- nodiscidee, and Coilopoceratidze. MOJSISOVICSIIDAE Hyatt. The single genus and species described below can not be even pro- visionally included in any of the groups to which it is supposed to be nearly related, and the following discussion of its generic affinities shows this conclusively. The dorsal sutures are not yet known, and this is the only defect in the evidence that establishes it as an independent group, probably belonging to the parent stock or stem of the Pachycampyli. MOJSISOVICSIA Steinmann. The interesting species used as the type of this genus has a form which is similar to that of Agassiceras of the Lower Lias in being smooth and discoidal, with flattened sides, narrow umbilical zones and rounded venter. The section is what I have called helmet shaped, like Agas. striar- ies. It differs in having no raised line or keel, and therefore comes a little nearer to Psiloceras. The sutures bear a similar interpretation, since, although these are very immature, there are four lateral bifid saddles with “A penciled note at the top of this page of manuscript says ‘‘ Revise list.’? Just what changes the author would have made can not be known, but it may be inferred that Lenticeratide was dropped as an abandoned family, and that possibly Coilopoceratide was assigned to another super- family. It is obvious that his conception of the group Mammitida had become very different from that expressed by him in Zittel’s Text-book.—T. W. §. 24 MOJSISOVICSITD 4. 25 subphylliform marginal saddles and excessively short pointed marginal lobes that are hardly more than serrations. The ventral lobe is very broad and divided. The first and second lateral lobes are narrow and similar to those of Buchiceras, but it should be noted that the dorsal sutures are unknown, and these may be quite distinct. The third lateral lobe is entire, and the fourth saddle hardly past the entire stage, exhibiting only a slightly trifid outline. Such sutures exhibit affinities with the smooth primitive ancestral stock of the Psiloceratidee of the Jura and other forms of Pachy- campyli descended from these because of their massive broad saddles, so entirely different from the narrow, excessively branched saddles of the Phyllocampyli and Leptocampyli. I do not, of course, mean that Mojsiso- vicsia is probably descended directly from Psiloceras, but it may be a Cre- taceous member of a primitive stock which began with Psiloceras in the Jura. The intermediate forms are as yet unknown or have not been pub- lished. The existence of such a trunk or main branch of a primitive stock from which all of the more complex groups are lateral offshoots has been inferred from the ontogeny as the most probable way to account for the ontogeny of the primitive species of these groups. Thus in the present instance the smooth discoidal young of Buchiceras and other genera can be readily accounted for if the comparison between them and the later stages of Mojsisovicsia is admitted. If such a stock of primitive forms existed, it is also easy to account for the maintenance of such primitive smooth psilo- ceran-like shells in the later nepionic and sometimes in the neanic stages of Cretaceous forms. Otherwise the continued renewal of these in the ontog- eny at such late stages must be referred to more ancient ancestors than any represented in the Jura. MossIsovicsta DURFELDI Steinmann. Pai hess l=3: Mojsisovicsia durfeldi Steinmann, Neues Jahrbuch fiir Min., Geol., und Pal., 1881, 1], p. 148, pl. 6. The peculiar fossil deseribed under this name has a compressed discoidal shell with slight constrictions, open umbilici, and smooth surface that in external aspect resembles Traneceras and also some of the discoidal Desmo- ceratidee like Pseudophyllites Kossmat, but has entirely different sutures. These have an aspect similar to those of Buchiceras bilobatum, but the form of the volution differs so widely that no further comparisons can be made 26 PSEUDOCERATITES OF THE CRETACEOUS. with this genus. The living chamber is short, the aperture has a blunt rostrum, there are shallow sinuses on the edges of the venter, a broad lateral rostrum on either side, and shallow sinuses between these and the umbilical shoulders, and probably a crest on the dorsum. The ventral lobe is very broad and short, with a broad short siphonal saddle. There are three bifid lateral saddles, with an incomplete apparently entire saddle at the line of involution. The lobes are short and much narrower than the saddles, and the entire outlines of both lobes and saddles have short obtuse marginal saddles and narrow, short, pointed, simple marginal lobes. The species is known to me only through Steinmann’s figures, which are reproduced on PI. I, figs. 1-3, with the single exception of his enlarged drawing of the side view of fig. 1. Locality: Pariatambo, Peru. Age: Albian (?). BUCHICERATID Hyatt. It has been found impracticable to unite the genus Buchiceras with any known family, on account of its peculiar development and sutures. The approximation to the Hystatoceratidz is close, so far as the earlier stages are concerned, the compressed, comparatively smooth-keeled young in the neanic stage having considerable resemblance, but these similarities are lost in the subsequent development, owing to the partial suppression of the costee and the very distinct sutures. The development and sutures separate these forms completely from Anemiceras. hey are separable from Tissotiidee by their first lateral saddles and their ventral lobes, and from Barroisiceras, which they also resemble, by the absence at all stages of a third line of tubercles and by their sutures. The‘sutures are similar to those of the discoidal smooth shell of uncer- tain affinities described as Mojsisovicsia by Steinmann. So far as known there are no representatives of this genus except in South America. It should be remembered, however, that all information heretofore published has come from this single fossil. The second genus included in this family, Roemeroceras, has similar ventral lobes and siphonal saddles, and the young, although quite distinct in being less compressed in the early stages, acquire a similar keel at a later age, and similar form and ornaments. BUCHICERATID 2. bo “| BUCHICERAS Hyatt. This genus was formerly described by myself as including several different species that have since been separated into distinct genera, by Douvillé, Grossouvre, and others, and by myself, in Zittel’s Text-book of Paleontology. The affinities of Buchiceras are not, in my opinion, very close to any of the forms formerly referred to Acanthoceras as supposed by some authorities. The sutures are quite distinct from those of any of the families of Mammitida on account of the extraordinary breadth of the second lateral saddles. The development is similar to that of some forms of Hys- tatoceratidee and Peroniceratide in that it is at first discoidal, compressed, and smooth, then keeled, becoming costated and tuberculated later, and the sutures approximate more closely to those of the young of these families perhaps than to others. Nevertheless the ontogeny differs in that Buch- iceras does not subsequently acquire prominent costz, and the keel tends to disappear instead of becoming larger with increase in size of the volutions. The nodes, on the other hand, increase in size and prominence, especially the inner row on the umbilical shoulders. The faint serrations on the keel and other ornamentation suggest affinities with Barroisiceras, but the sutures and the absence of a third line of lateral tubercles, which appear in some forms of Barroisiceras, are not favorable to this solution of the affinities. The same objections apply almost equally to keeled forms of the Prionotropidee in which the young resemble more or less closely those of B. bilobatum. The dorsal sutures are very remarkable and perhaps may eventually assist in placing this genus in closer connection with others. The primitive first lateral saddle is retained in Buchiceras until a late stage, and perhaps throughout life; it is undivided, except by small entire marginal lobes, but it is distinetly bifid. BucHICERAS BILOBATUM Hyatt. Pl. I, figs. 4-9. Buchiceras bilobatum Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, p. 370. Buchiceras bilobatum Douvillé, 1890, Bull. Soc. géol. France, 3d ser., Vol. XVIII, p- 284. The young, for the first two, and perhaps part of the third volution, must have had smooth sides and was obviously very discoidal, flat, and keelless. The aspect of this species must have been very similar to Mojsi- sovicsia. The keel comes in upon an elevated venter previous to reaching 28 PSEUDOCERATITES OF THE CRETACEOUS. the diameter of 5 mm. and is faintly sinuous during the latter part of the volution seen in Pl. I, fig. 4. These faint undulations are due to prolonga- tions of the coste that pass between the tubercles on the ventro-lateral angles. This keel, which is a mere angle on the venter, was obviously continuous before the coste appeared and is practically continuous subse- quently, owing to the minute character of the inflections. Upon the last of the outer volution at this diameter, the first of the fourth volution, the outer line of tubercles appears and is connected by coste with the inner line. The last are very widely separated at first and become nearer only in later stages. The larger costee at this age are separated by single, arcuate costa- tions terminated outwardly by minute tubercles and fading out mternally about halfway across the volution. The umbilical zones are not differenti- ated from the sides. The side is evenly plano-convex from the keel to the line of involution and the inner, uncostated part is smooth, except where interrupted by the inner tubercles or extensions of the tubercular termina- tions of the larger costee. The tubercles and nodes are opposite, not alternate. The sutures at this age consist of two large saddles (PI. I, fig. 9), a narrow first lateral lobe in the center of the lateral zone and a broad second lateral on the umbilical zone. he inflections are all apparently entire. In succeeding stages the lobes remain in the same position, there being but one in the center of the side between the two rows of tubercles and one on the umbilical shoulder, but as the shoulder becomes more prominent and the umbilical zone broadens, other lobes and saddles appear internally. The venter broadens with age, the keel becoming more obscure in consequence of this; the sides become flat and convergent; and the umbilical shoulders broaden out more than the venter, the increase in the umbilical zones making the umbilici very deep. The keel on the cast at this mature stage is faintly undulated, and the lateral costze, although very obscure, cross the venter and interrupt the keel between each pair of opposing ventro-lateral nodes. These widely separated serrations are so faint on the cast that they entirely escaped my observation on former occasions. They in fact can be. felt more easily than they can be seen. This is also the case in the earlier stages described above. The inner nodes are always larger and fewer than those on the edges of the venter. ‘The second lateral saddle remains broader than the first lateral, even when the shell is somewhat over 40 mm. in diameter. It occupies a trifle more than half of the side and encroaches on the umbilical zone (Pl. I, fig. 8). BUCHICERATID &. 29 The ventral lobe is very widely open at the base and longer than the first lateral lobe. The two arms are blunt and very small. The siphonal saddle is phenomenally short and broad, with a faint centran marginal lobe and an equally faint marginal rounded saddle on either side. The first lateral lobe is funnel shaped, broad at the base, short and narrowing rapidly to a bifid termination. The second lateral lobe is very much smaller and shorter, and entire at the end. The third lateral saddle is small, entire until a late stage, but becoming bifid later. Beyond are two small entire saddles and two corresponding lobes or what may perhaps be more accurately described as a bifid lobe and a bifid saddle. The first and second lateral saddles have internal ridges, but these coalesce, forming a short, flattened area along the mesal plane, which becomes deeply convex toward dorsum and venter. There are only two broad saddles and two narrow lobes on the dorsum, and these have no connecting ridges with the external saddles. The surfaces of the wings of the septa are strongly inclined inward, the outer sutures being considerably in advance or orad of the inner ones. This gives a remarkably concave. aspect to the wings of the septa on either side of the dorsum. The dorsal sutures, which were worked out with difficulty, show that the inner arm of the bifid fourth lateral saddle passes across the line of involution, coalescing with the third dorsal saddle. The antisiphonal lobe is asymmetrical, entire at the top, unequally serrated on the sides, and bent over to the left until the tips touched the inner angles of the first pair of dorsal saddles to the right of the mesal plane of the body. The first pair of dorsal saddles are deep and broad with broad entire bases. The first lateral lobes are small and unequally bifid, the sides being coarsely serrated. The second dorsal saddles are much inclined and obscurely tridentate or entire. The second dorsal lobe is very small and entire. The third dorsal saddle is a part of the fourth lateral, as stated above, and is entire. Vestiges of the shell were present upon this cast in a few places and showed coarse lines of growth. Unfortunately the shell covering the venter of the young whorl was chipped off in cleaning this part for drawing, and evidence of the statement made above with reference to the keel was lost. Locality: Cachiyacu, west side of Hullagua River, Peru. Age: Upper Cretaceous. B10) PSEUDOCERATITES OF THE CRETACEOUS. ROEMEROCERAS Hyatt. These shells were so similar to the type of Buchiceras in external aspect that I formerly supposed the type of this genus to be an older stage of B. bilobatum, but more prolonged acquaintance with these forms shows that they are not in the same generic group. While the bifurcated costz, the large nodes on the umbilical shoulders, and the nodes on the ventro-lateral angles are the same, the involution is greater, the lateral zones more com- pressed and broader, the umbilici narrower, the young have larger nodes, and the keel entirely disappears in the full-grown shells, except perhaps in R. gabbi. he sutures are also quite distinct, and similar to those of Tisso- tidee in some species, but the first lateral saddles tend to develop three arms in some species and the bases of the other saddles are apt to be dentated more or less completely. The ventral lobes are similar to those of Buchi- ceras and entirely distinct from the broad ventrals of the Tissotiide. The same characters appear to unite K™nemiceras with Roemeroceras, but the development and full-grown shell in Anemiceras, especially the invariable presence of the concave venter, seemed to place it in closer association with the Pulchelliidee. RoEMEROCERAS GABBI n. sp. Hyatt. Pl. II, figs. 1-3. Ammonites bilobatus Gabb, 1877, Jour. ANea Nat. Sci. Pe Pa 2d ser., Vol. VIII, p. 270, pl. 38, fig. 3. In my revision of this form I made too great allowance for the possible variations due to age, and misled Professor Gabb in identifying this fossil with Buchiceras bilobatum. As compared with B. bilobatum, the nodes on the umbilical shoulders are much less prominent and more numerous and more closely approximated, the venter has large ridges not present in bilobatum, and the flatness and proportions of the saddles are too distinct to occur in the same species, even though allowance be made for the sutures in gabbi being nearly one volution older than those examined in B. bilobatum. The sutures of this species approximate more closely to those of R. syriaciforme than to those of any other species, but R. gabbi differs in the greater number and smaller size of the nodes and coste. Fig. 3 of Gabb’s plate shows the lateral aspect with an outer line of nodes lower on the sides and a simuous outline to the venter which does not appear in syriaciforme, and also a BUCHICERATID 2. 31 stouter and more quadragonal volution than any other species of this genus. The originals of this species were not reexamined. They could not be found in the Academy’s collection at the time of my visits, nor has subse- quent search, made by the kindness of Professor Pilsbry, brought them to light. Locality: Quebrada de Colpamayo, Department of Cajamarea, Peru. Age: Upper Cretaceous. ROEMEROCERAS SYRIACIFORME Hyatt. Pl. I, figs. 10-14. foemeroceras syriaciforme Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, p- 371. This species reaches a diameter of 90 mm. in one cast without a living chamber. The sutures are approximated and overlap internally on the auxiliaries, showing that the gerontic stage has begun. The ornamentation and form are the same as in bilobatum. When the east is only 29.5 mm. in diameter there is, however, no difficulty in separating this from bilobatum. It is more compressed, the sides broader, the venter narrower and flatter. The sutures have more resemblances to those of R. gabbi, but the saddles and lobes are never so short, nor truncated, the saddles being narrower and the lobes broader. The ventral lobe and siphonal saddle are similar, but narrower and less digitated. The first lateral saddles are similar in being bifid and rather broad, but already at this early stage show denticulations over the entire base. The first lateral lobe is similar but less deeply divided, by the similar marginals. The second lateral saddles are unequally bifid with bases rounded or approximately phylliform, entire, and unlike those of gabbi. The second lateral lobes are quite broad, apically like the first laterals, but are unequally quadrifid. he third lateral saddle is as broad as the second lateral, and also bifid. It occupies part of the side and also part of the umbilical zone, the marginal lobe being upon the umbilical shoulder. Inside of this there is one broad bifid saddle reaching to the lobe at the line of involution. There are therefore four saddles at this early stage very like those of gabbi, except in having rounder bases. Later, on the same volution, this inner saddle becomes divided into two by a median marginal lobe, and still later a small lobe makes its appearance at the line of involution, completing the outline of the innermost lateral saddle. There are then five saddles and six zygos lobes on either side. 32 PSEUDOCERATITES OF THE CRETACEOUS. The oldest sutures are very much changed, and look like those of a distinct species, but are obviously in the gerontic stage. The bases of the saddles are nearer together, the entire parts of the sides much elongated, and the lobes longer and narrower and the digitations situated at their apical ends much deeper. The saddles are longer and broader, with entire bulging sides, and the marginals not increased in number, but much longer and larger. The sutures have at this stage close similarity to the peculiar outlines attributed to Ammonites syriacus by von Buch (fig. 1 of pl. 7 in his Uber Ceratiten), but the first lateral is not so broad and does not have the minute phylliform marginals of that figure. The marginals on the first lateral saddles, and also in the first lateral lobe, are tongue shaped. The fourth and fifth lateral saddles are entire, tongue shaped, and divided by a narrow bifid lobe. The young sutures, until a late neanic stage, have outlines similar to those of some species of 7%ssotia. After this the outer saddles become completely denticulated, and again, as described above, lose a considerable part of these denticles in old age. Fragments of the shell were present on the largest cast. None of the specimens was incrusted by any extraneous growths that could be shown to have fastened themselves on the surfaces of the casts. The figure of the young in an early ephebic substage (PI. I, fig. 12) is a very near approach to the old specimen which was crushed on one side (PL. I, fig. 10), but of course, owing to differences of age, the nodes are larger. There are fifteen nodes on the ventral border and six on the umbilical shoulders on one volution of the younger specimen, and eleven on the outer and seven on the inner row of the old specimen. The bifid costz are also present in the younger specimen, mingled with single ones, as in the old stage. The keel disappears on the last quarter of the outer volution, both on the cast and on the shell, in the young specimen, and is absent also in the older one. The young shell was seen in a section of the specimen represented by fig. 12 of Pl. I, and although not perfect enough to figure, showed that when about of the same size as the young of B. bilobatum (Pl. I, figs. 5, 7), it had a similar keeled form. Locality: Cajamarca, Peru. Age: Upper Cretaceous. “See also description of R. attenuatum Hyatt. BUCHICERATID.®. 33 RoEMEROCERAS ATTENUATUM (Hyatt). Pl. I, fig. 15. Buchiceras attenuatum (pars) Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, p- 372. The cast differs from syriaciforme in having more numerous nodes on the inner line. On the outer volution, at a diameter of 64 mm., there are about nine on the inner row and sixteen on the outer, whereas in syriaci- Jorme, at a diameter of 90 mm. there are seven on the inner line and eleven on the outer line; in another specimen of syriaciforme, at a diameter of 73 mm., there are the same number; in another, at a diameter of 34 mm., there are six on the inner and fourteen on the outer line; in another, at a diameter of 41 mm., there are seven on the inner line and fifteen on the outer. There are faint signs of a keel on the type specimen, showing that it belongs in this genus. The general form is much more compressed than that of R. syriaciforme ; the venter is narrower and the keel is also less devel- oped. The volutions are more enveloping, and the umbilicus is smaller. The specimen is a cast, partly crushed on one side and somewhat worn on the other, but although the sutures are not consequently perfect they are entirely distinct from those of other species. The first lateral lobes are bifid and shorter than the ventral lobe. Instead of being of about the same length or longer than the ventral, as in R. syriaciforme, all the saddles are broad and very short, as are also the lobes. The first lateral saddles and lobes are completely denticulated by marginals. The second lateral is trifid, the third and fourth saddles are bifid, and there is a fifth saddle, but this is on the line of involution and very narrow. The second lateral lobes are trifid. The third lobe is in the umbilical zone and bifid, but otherwise entire, and the fourth is very small and apparently entire, but too much worn to make observation certain. There are incrusting ostreans upon both sides of this cast and they appear to have been attached to a fossil cast. This species is founded upon a single fossil cast, one of the two used for the description of Buchiceras attenuatum Hyatt, but not the type. The latter is to be found on page 151, under the name of Anemiceras attenuatum Hyatt. Locality: Celendin, Peru. Age: Upper Cretaceous. MON XLIV—03 3 o a4 PSEUDOCERATITES OF THE CRETACEOUS. ROEMEROCERAS SUBPLANUM un. sp. Hyatt. Pl. II, figs. 4-6. This specimen is a cast, whole diameter 55 mm _ The lateral zones are flatter than in R. syriaciforme and denticulatwm, and the outer nodes are smaller, more acute, and have slight ridges or orad continuations in some eases. The inner nodes are also smaller in the young and increase very rapidly in size on the last volution and then suddenly disappear, the volution becoming at the same time contracted to a subquadrate outline. There are four small and three large nodes on the inner line, the place where the fifth node ought to be is vacant, and there are fifteen nodes on the outer line. The living chamber, which is probably very nearly complete, is less than one-half of a volution in length The last two large nodes of the inner line are on this chamber. The sutures have very broad, short, simple saddles and very short lobes. They are similar to those of R. denticulatum but have not such complex outlines. The last six sutures are nearer together and become finally closely approximated, showing that the fossil is probably an out- grown shell. This cast having been cracked open, it was possible to study exactly the contact of incrusting ostreans with the surface. It was found, as in other cases described, that no shell layers were present, the ostrean having grown directly upon the surface of a fossil cast. The shell is present in the impressed zone where it is protected’ by the enveloping volutions, and it is there thick and well defined. Locality: Cajamarca, Peru. Age: Upper Cretaceous. PSEUDOTISSOTIID Hyatt. If the position here taken is correct, the genera assembled under this name are distinct from those heretofore included under the Tissotiidee They include forms from the discoidal channeled and keeled Pseudotissotia in the Turonian to the highly involute compressed Plestotissotia of the Senonian. The lobes have the same denticulated outlines as in Tissotide, but the saddles are more complex, being denticulated in all the genera except Plesiotissotia, in which they are all bifid, the first lateral saddles being quadrifid according to Peron’s figure. PSEUDOTISSOTIID.®. 35 The relations of the genera in this family can only be estimated by their full-grown shells and sutures, and doubtless any arrangement that can now be made will be only provisional. So far as the facts 20, Pseudotissotia is a flat-ventered, keeled, and channeled form until a late age, losing its keel in old age and having so close a resemblance to Tissotia tissoti that it seems to be the only form having any claims to be considered the ancestor of that species, as first pointed out by Peron. Choffaticeras, wntil a late age, has a venter with keel and channels like those of Pseudotissotia in C. meslei but combined with an inflated volution and deep, abrupt umbilici and highly inclined, convergent sides. In other species the line of modifications indicated by the later stages of its ontogeny leads into forms having subacute venters at a comparatively early age, and possibly the keeled and channeled stage with its flat venter may have altogether disappeared in some of these. The highly involute, compressed- keeled forms of Hemitissotia follow these in the same line of modification and as their sutures also coincide and they occur in the Senonian, whereas all of the above-described genera are Turonian, Peron’s idea that they are the direct descendants of Pseudotissotia seems to be well sustained. That these are not transitional to true Tissotia becomes apparent when it is recognized that the type form of that genus has an ontogenetic history like that of Psewdotissotia and is probably, as stated in the deseription of the Tissotiidze, the most primitive member of a series of forms distinguished by their differences of development as well as by their simpler and more retrogressive sutures. Although the sutures differ decidedly, the forms of more primitive species like Pseudotissotia galliennet and their keels appear to place them provisionally nearer to the Buchiceratidee than to the keelless forms. I have had no fossils for examination in this family, but the literature and the figures given by Grossouvre and Peron have been sufficient to enable me to arrange the forms provisionally and to make comments upon their probable relations that will, it is hoped, attract attention and lead those who have better opportunities to test the truth of the views presented below. PSEUDOTISSOTIA Peron. Peron’s typical species, Ps. galliennei, is a discoidal form with keel and channels, having obviously, as observed by Peron, genetic affinities with 36 PSEUDOCERATITES OF THE CRETACEOUS. true Tissotia as here defined, but it differs in the more complex outlines of the sutures, all of which have small marginal lobes and saddles. In my opinion, the genus should be limited, so far as known, to one species, the type described by Peron. The other species described under this name are obviously widely distinct in their forms and mode of development. The sutures resemble those of Roemeroceras ou the lateral aspect. The ventral lobes are also alike, so far as can be seen on Peron’s figure. Peron’s sug- gestion that these are the ancestors of Tissotia and its allies in the Senonian appears to be supported by the facts so far as now known. They appear also to have been the immediate ancestors of Hemitissotia and its allies in the Senonian, but this last inference needs confirmation that can only be obtained through the study of the young of the latter. PSEUDOTISSOTIA GALLIENNEI (d’Orbigny). Pseudotissotia galliennei Peron, 1896, Mém. Soc. géol. France, Paléontologie, Vol. WIL No, Wt, jalle 25 ier, BS joll GB, ines I This is a moderately compressed but still comparatively discoidal form, with large umbilicus and involution enveloping something more than one- half of the sides, according to Peron’s figures. The venter is flattened, with heavy, contmuous keel and shallow channels bordered externally by thick continuous ridges. The sides have very broad fold-like costae with- out tubercles. In extreme age all of these ornaments disappear. The entire aspect and genetic transformations of this fossil are so similar to those of Tissotia tissoti that it would have to be included in the same genus, if the sutures were unknown. Locality: France. Age: Turonian. PSEUDOTISSOTIA ? TUNISIENSIS n. sp. Hyatt. Tissotia ct. fourneli Peron, 1896, Mém. Soc. géol. France, Paléontologie, Vol. VI. No. 17, pl. 12, figs. 7, 8. Tissotia fourneli Peron, 1890, Moll. Crét. de la Tunisie, pl. 17, figs. 11-13. . This remarkable fragment has a truncated venter, entire keel, and compressed volution, with moderately large umbilicus. The coste are fold- like, with tubercles on the umbilical shoulders and a line of closely set elongated tubercles on the ventro-lateral angles. The first lateral saddles are trifid and rather peculiar, owing to the approximate equality of the three PSUEDOTISSOTIID®. ot marginal saddles. The other saddles are very long and phylliform, and according to Peron’s figures the third saddle is trifid or bifid. These sutures and the ventral lobe, with its steep denticulated sides and truncated siphonal saddle, are similar to the sutures of the old stage of Roemeroceras syriaciforme. The form and ornamentation also agree with this determina- tion, but the keel is more prominent than is usual in this genus. It is pos- sible to understand this form, if it is related to Ps. galliennei, because in that case the keel and lateral costee are similar to those of that species. The differences in sutures lie largely, according to Peron’s figure, in the second lateral saddles, which are entire. This may be due to retrogression. Locality: North Africa. Age: Santonian. CHOFFATICERAS un. gen. Hyatt. This genus has sutures similar to those of Pseudotissotia, but the form is distinct. The species are more or less stout gibbous forms with more or less open and deep umbilici. The sides are heavily costated and nodose along the umbilical shoulders, but there are no external tubercles according to Peron. He also describes the venter as having a continuous keel and two ventro-lateral ridges. The form is more involute and more compressed than Pseudotissotia, and the outer parts of the volutions have a tendency to become concave in the involute species with broad volutions. The type is C. meslei (Peron). SHOFFATICERAS BARJONAI (Choffat). Pseudotissotia barjonat Choffat, 1898, Faune Crét. du Portugal, Vol. I, 2d series, pl. 18, fig. 3; pl. 22, figs. 40-42. This species is a close ally of C. meslei of North Africa, as has been stated by Choffat, but has a more prominent keel and has no signs of channels on the venter. Locality: Portugal. Age: Vuronian. CHOFFATICERAS MESLEI (Peron). Pseudotissotia meslei Peron (pars), 1896, Mém. Soc. géol. France, Paléontologie, Vol. V1, No. 17, pl. 1, fig. 1; pl. 2, fig. 1 (not pl. 2, fig. 2, nor pl. 3, fig. 2). This species has a form which is sublenticular when seen from the front in Peron’s figure, owing to the great prominence of the umbilical 38 PSEUDOCERATITES OF THE CRETACEOUS. shoulders and the rapid slope of the lateral zones and subacute character of the venter. The costz are linear and only slightly curved in the only well-preserved part of his type as figured. The involution covers about three-fifths of the next inner whorl, leaving a rather large open umbilicus showing the younger whorls. The more discoidal form (pl. 2, fig. 2, and pl. 3, fig. 2) supposed to belong to this species, is certainly distinct specifically and may be nearer to Pseudotissotia than to any species of this genus, but it is too imperfect to give diagnostic characters. Locality: North Africa. Age: Turonian. CHOFFATICERAS? DOUVILLEI (Peron). Pseudotissotia dowvillei Peron, 1896, Mém. Soe. géol. France, Paléontologie, Vol. VI, No. 17, pl. 2, figs. 4, 5, and pl. 3, figs. 3, 4. This species, as figured and described by Peron, has the general form and aspect of C. meslei, but the heavy nodes on the umbilical shoulders and dichotomous coste reaching to the sides of the prominent keel are auite different. Locality: North Africa. Age: Turonian. HEMITISSOTIA Peron. This genus seems to me to be more intimately related to Choffaticeras than to Tissotia and other genera having similar forms but having sutures with smooth saddles. Such questions can only be definitely settled when the younger stages become known. These involute and more or less com- | pressed forms with trenchant keeled venters are apparently in the direct line of modifications indicated by the similar forms of Tissotidee, but on the other hand their sutures correlate with the more complex outlines of those of Pseudotissotia and Choffaticeras, and this indicates that they are simply parallel as representative forms analogous to some of the Tissotide but really in the genetic line of Choffaticeras. They have retrogressive characters in the undivided outlines of their inner saddles, but this arrest of development has not affected the outer saddles that are completely digitated. They can not be placed anywhere in the genetic line between Pseudotissotia and Subtissotia on account of the absence of channels and PSEUDOTISSOTIID.X. 39 ridges on either side of the keel, and this is the only position that could be claimed for them in view of their peculiar sutures. All of their characters accord best with the view that they are direct descendants of Choffaticeras. There is an interesting group of this or an allied genus from the Senonian, described by Choffat in his Céphalopodes de la Faune Crétacique du Portu- gal, Vol. I, 2d series, but the condition of the specimens did not permit him to describe them sufficiently to judge closely of their affinities. HeEmitissoTia CAZzINI Peron. Hemitissotia cazini Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No 17, pl. 14, figs. 1-5; pl. 18, figs. 9, 10. This species is a highly involute compressed form, and in the oldest specimen figured the first and second lateral saddles are completely denticulated, the third is equally divided by a median marginal lobe in the figure of the suture of the oldest specimen (pl. 18, fig. 9), but this is not described in the text. ; Locality: North Africa. Age: Senonian. Hemitissotia? BaTNENSIS Peron. Hemitissotia? batnensis Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. WATTEON GO alicopla lion host a(S This species has the external aspect of this peculiar group and the sutures are similar as figured by Peron, but his question mark after the generic name is justified by the Sphenodiscus-like aspect of the first lateral saddles. Locality: North Africa. Age: Senonian. HEMITISSOTIA MORRENI (Coquand). Hemitissotia morreni Peron (pars), 1897, Mém. Soe. géol. France, Paléontologie, Vol. VII, No. 17, pl. 15, figs. 1 and 2 only, and pl. 18, fig. 11. Hemitissotia morrent var. precipua, ibid., p. T7. This var. precipua of Peron is a highly compressed form with acute venter. Pl. 15, fig. 8, may be the young of this species, and if so, it shows conclusively that it is distinct from the following. Locality: North Africa. Age: Senonian. 40 PSEUDOCERATITES OF THE CRETACEOUS. HEMITISSOTIA TISSOTIEFORMIS Peron. Hemitissotia morreni var. tissotieformis Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 17, pl. 15, figs. 3-5 only. This is a much stouter form with stouter volutions, and as might: be expected in such a species the young exhibits distinct ribs. Hemitissotia morrent var. coquandi (pl. 15, fig. 6) may be distinct, but no front view is given and the sutures shown in pl. 18, fig. 14, do not appear to be very different. Locality: North Africa. Age: Senonian. HEMITISSOTIA DJELFENSIS (Peron). Tissotia djelfensis Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 17, pl. 16, figs. 3, 4. Buchiceras ewaldi (pars) Peron, 1890, Moll. Crét. de la Tunisie, pl. 15, figs. 7 and 9 (no others). This is a compressed shell very closely allied to Paratissotia ficheuri in aspect, but differing in the sutures. These have the first lateral saddles narrow and bifid as in Hemitissotia and the first lateral lobe is large as in that genus. he figure of the highly compressed cast given by Peron as part of his ewaldi in the Mollusques Crétacé de la Tunisie has very similar sutures so far as the deep division of the first lateral saddles and lobes is concerned. It is better to quote it here, since it is undoubtedly not related to the other species on the same plate and has also a form similar to that of djelfensis. Locality: North Africa. Age: Lower Senonian. HEMITISSOTIA CEADOUROENSIS Choffat. Hemitissotia ceadouroensis Chofiat, 1898, Faune Crét. du Portugal, Vol I, 2d series, pl. 20, figs. 7-10. This species is apparently a member of this genus and is of interest in showing the old-age transformations, the rounding of the venter and contraction of the outer volution. If the last part of the last volution is perfectly natural, it shows an extraordinary senile scaphitoid deviation from the spiral. Locality: Portugal. Age: Senonian. PSEUDOTISSOTIID_E, TISSOTITDA. 41 PLESIOTISSOTIA Peron. This genus has been founded by Peron entirely upon the differences of the sutures as compared with Hemitissotia. The first lateral saddles are broad and very deeply divided by a median marginal lobe and each arm is phyllitorm and is also subdivided by a median marginal lobe; the remaining saddles are phylliform and equally subdivided by median marginal lobes. It is a question whether these peculiar sutures really represent another group or are simply retrogressive modifications in the genetic line of Hemitissotia. ‘The compressed and costated form does not indicate affinities, but, as stated by Peron, the divided saddles are similar to those of Hemitissotia precipua, except the first laterals, which are narrow and irregular in outline in the latter. PLESIOTISSOTIA MICHALETI Peron. Plesiotissotia michaleti Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. WIUL NOs JING fol Wa, mes, M5 tS A highly compressed keeled form with costze having tubercles on the umbilical shoulders, as in some species of Hemitissotia. The sutures are described in the notice of the genus. Locality: North Africa. Age: Senonian. TISSOTIIDA Hyatt. This family name is here much narrowed in its application as compared with what it was in my chapter on Cephalopoda in Zittel’s Text-book. It is now considered applicable to a series of genera that includes only Tissotia and its immediate allies, excluding Pulchellia, Psilotissotia and Lopholobites. The genera can be described as having keeled forms, with channels only in primitive genera. The keels have a crenulated or nodose stage in a number of primitive genera, but are continuous in the flattened forms. Coste are present in the globose primitive forms and are usually tuberculated, and when they disappear the nodes are apt to persist. The venters lose their keels and become rounded or flattened in old age. One genus has a hollow keel (Paratissotia) and others may have hollow keels. So far, however, the only fact in favor of this is the presence of prominent keels on the shells that have no corresponding keel elevations on the casts. The sutures are 42 PSEUDOCERATITES OF THE CRETACEOUS. characteristic, having simply digitated or phylliform, often entire or bifid saddles and narrow, often club-shaped, lobes digitated at their tops. The first lateral saddles are usually bifid, but in some forms they become trifid. In these cases the additional saddles are added on the ventral side through the division of the outer arm of the first lateral saddle. The group as here defined is confined to the Lower Senonian in Europe, and the South American representatives are probably of about the same age. TISSOTIA Douvillé. The definitions heretofore given of this genus have been based upon the sutures which, according to the views here advanced, can not be accepted when not correlatable with external characters. The type of this genus, T. tissoti, so far as can be seen from the side view given by Bayle and the front view by Douvillé, is unique in having a considerably inflated form like some species of Stbtissotia, but with keel and ventral channels bordered by continuous ridges, and in the extreme gerontic substage a truncated venter without either keel or channels. This certainly justifies the opinion of Grossouvre that this species is closely related to Pseudotissotia galliennei. According to the views here advocated, this genus is a direct derivative of galliennei of the Turonian, as has been previously suggested by Peron. Tissoria TissoTi (Bayle). pl. 12, fig. 3. The type of Bayle’s species, which is also the type of his genus Tissotia, has been figured by him in side view and by Douvillé in front, from the same type in the Ecole des Mines, Paris. Douvillé also describes the specimen. It is therefore plain that it is a stout form without any very marked nodes and is flat on the venter in its gerontic stage, having lost its keel on the last part of the outer volution according to Bayle’s figure, which is natural size, and also Douville’s figure. This shell also, according to Douville’s figure, preserves an unusually depressed venter having keel and shallow channels on either side bordered by faint ridges or carinz throughout the adult stage. The loss of the keel is correlated with loss of the gibbosity of the sides, these becoming flatter aud more convergent outwardly. TISSOTIID®. 43 SUBTISSOTIA n. gen. Hyatt. This group includes a number of the species heretofore associated with Tissotia tissoti on account of the sutures. These are unquestionably similar in the simplicity of their outlines, but, as has been argued above, this fact can not be considered as determinative in such peculiar retrogressive groups, unless correlatable with other characteristics and especially with the changes in the development both of the young and the gerontic stage. The younger stages, so far as known, beginning with the neaniec stage, have, as a rule, very globose forms with continuous keels, the sides are costated and terminate outwardly, with tubercles that form raised but discontinuous ridges on either side of the keel. The venter is much broader than the area included within these lines of nodes, except in the gerontic stage, when it narrows down to the same limits as are common in Metatissotia. The keel disappears in the gerontic stage and the lateral coste and the nodes also in some species, according to Peron’s figures, leaving the venter more or less rounded. Type is Subtissotia inflata (Peron). SUBTISSOTIA INFLATA (Peron). Tissotia tissoti var. inflata Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 17, pl. 19, fig. 6. The figures of this form, given by Peron, show an excessively stout shell, increasing rapidly in transverse diameters by growth, with an obtusely subacute venter, prominent keel, and slight channels on either side, bordered by ridges. Peron’s figure at diameter of 68.5 mm. is 51 mm., while the figure of intermedia, which is 92 mm. in diameter, is 53 mm., only - 3 mm. wider than the much smaller and younger specimen of inflata. Such differences of proportion do not occur in the same species of Ammonites. Locality: North Africa. Age: Base of Senonian. SUBTISSOTIA INTERMEDIA (Peron). Tissotia tissoti var. intermedia Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VU, No. 17, pl. 12, figs. 4, 5. Tissotia tissoti var. levigata Peron, ibid., pl. 13, figs. 1, 2. This form differs from inflata in having much less gibbous volutions at the same age and a more acute venter at all stages. 44 PSEUDOCERATITES OF THE CRETACEOUS. Locality: Northern Africa. Age: Lower Senonian. SUBTISSOTIA PERONI n. sp. Hyatt. Buchiceras ewaldi Peron, 1890, Moll. Crét. de la Tunisie, pl. 15, figs. 1, 2 (no other). Tissotia ewaldi Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 17, p. 68. This is based on a specimen from Tunis, of a diameter of 107 mm. It is figured by Peron as having an entire keel throughout, although the rounded tubercles on either side of the ventro-lateral angles have almost disappeared at a stage when in his ewaldi var, africana they would have become elongated and very coarse and the keel have been resolved into elongated tubercles. The venter is also entirely distinct in this species, in its sharper outline and more prominent keel. These features are also associated with peculiar sutures. The sutures of Tissotia africana have a long, well-defined ventral lobe, the sides of the first laterals being abrupt, whereas in this fossil there is a very short, ill-defined ventral lobe, with the sides of first lateral saddles denticulated and sloping. The first lateral saddles are deeply divided in 7. africana, while in this the division is not so well marked. The resemblances in form and sutures between this and T. levigata show that they are closely related. Locality: North Africa. Age: Base of Senonian. SUBTISSOTIA AFRICANA (Peron). Tissotia ewaldi var. africana Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 17, pl. 11, figs. 1-6. Ata diameter of 54 mm. the young figured by Peron is a very gibbous form, in which the broadest diameter of the last volution measures about 39 mm. The keel is continuous and prominent even on this cast, and there is a line of prominent tubercles on either side along the ventro-lateral angles. In the aged specimen, figured at diameter of 108 mm., these have become elongated, and the sides being less gibbous the venter is flatter, and on this volution the keel begins to disappear, becoming resolved into elongated nodes. There are no costz figured on these casts. Peron con- siders this identical with Tissotia robini, as figured by Grossouvre, but robina TISSOTIID®. 45 is a costated compressed species with a continuous keel, even in extreme age, after the disappearance of the lines of tubercles, according to Grossouvre’s figure. His ewaldi is similarly figured as a compressed shell, but not in extreme of age apparently. This species is evidently distinct from T.ewaldi figured by Peron in his Mollusques Crétacés de la Tunisie, which attains a large size, and at an advanced age still has an entire keel and rounded tubercles. The resemblance of the youngof this species to the more mature stages of Subtissotia inflata and intermedia is apparent, if Grossouvre is correct in his assignment of the smaller casts figured to this species. Locality: North Africa. Age: Lower Senonian. METATISSOTIA n. gen. Hyatt. Following out the system adopted in these pages, it becomes obvious that species having the peculiar development of Metatissotia fourneli and robini can not be associated with either Tissotia or Subtissotia. The entire ontogeny, including the gerontic stage, of these highly compressed forms is distinct from Zissotia and Subtissotia on the one side and from the more accelerated development of Paratissotia on the other. The typical ontogeny begins with a stage having a compressed smooth form and a continuous keel. In the next stage there is a more or less trun- cated venter having also a continuous keel, but with nodes at the termination of costee that appear on the sides, and nodes also on the umbilical shoulders. In the gerontic stage, the cost, keel, and channels finally disppear, leaving the sides smooth or ornamented only with large nodes, and the venter more or less angular. MeraTissoTia FOURNELI (Bayle). Buchiceras fourneli Bayle, 1878, Expl. de la Carte géol. France, Vol. IV, pl. 40, fig. 3 (not fig. 4). Tissotia fourneli Peron, 1890, Moll. Crét. de la Tunisie, pl. 15, figs. 10-14. Tissotia fourneli Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. iLife Yolls al(0) The development has been determined by Peron in his Ammonites de lAlgérie, cited above. In the figures of his youngest specimen, which measures about 30 mm. in diameter, there are large dichotomous cost with alternating short single costze. In the oldest part of this specimen and in 46 PSEUDOCERATITES OF THE CRETACEOUS. the stage represented by the next figure, the forks of the dichotomous costz are becoming obsolete and being resolved into short coste, so that there are two short nodose coste between the larger ones. This is obviously, how- ever, very irregular, since in the figured specimen, which has a diameter of 85 mm., there is still one dichotomous costation. It is obvious, too, that the costee, bemg very heavy, become fold-like with age. The longer cost have nodes on the outer ends along the ventro-lateral angles, and nodes along the umbilical shoulders, which persist throughout the ephebic stage and are present as very broad, low folds in the gerontic stage. According to Peron’s description and figures, the short costae disappear and are appar- ent only as simple nodes in large specimens. This is a compressed form of this genus having an entire keel at an early stage, and a close ally of the European species M. nodosa. Peron has clearly shown that Bayle confounded two species under this name, but I doubt whether Bayle’s Tissotia fowrneli, figs. 4-5 of pl. 40, is identical with ewaldi. Locality: North Africa. Age: Base of Senonian. MeratissoTia RopINI (Thiolliére). Ammonites robini Thiolliére, 1848, Ann. Soc. d’Agriculture de Lyon, Vol. XI, jolt al Buchiceras ewaldi Fallot, 1885, Ann. sci. géol., Vol. XVIII, pl. 3, figs. 1, 2.7 Ammonites cfr. ewaldi Redtenbacher, 1873, Abhandl. K.-k. geol. Reichsanstalt, Vol. V, pl. 22, figs. 5 a-i. Tissotia robini Grossouvre, 1893, Ammonites Craie supérieure, pl. 4, fig. 1 (not fig. 2 b). Tissotia ewaldi (pars) Grossouyre, ibid., pl. 9, fig. 5. This shell has a compressed form, and the adult figured by Grossouvre at a diameter of about 50 mm. has a truncated venter with prominent elon- gated tubercles on the ventro-lateral angles and a prominent continuous keel. At the end of this volution, or say at a diameter of 55 mm., accord- ing to Grossouvre’s figures, these tubercles begin to disappear, and at a diameter of 80 mm. they are absent, and the venter has consequently lost its truncated aspect and become subacute. This agrees also. with Redten- bacher’s figure of a specimen which is 83 mm. in diameter, and in which TISSOTIID. 47 the old-age characteristics are similar. Grossouvre’s fig. 2, also named robini, is apparently a distinct species. It has the subacute venter of the oldest gerontic substage of true robini when only 59 mm. in diameter, and this begins when the shell was about 40 mm. in diameter or earlier, accord- ing to this figure. This whole volution is also covered by dichotomous costae having only very faint tubercles. This might be a dwarf of this species, but is apparently not a young specimen. Redtenbacher’s figures (except perhaps 5, f and h) all appear to belong to this species, and fig. 5f may have been a worn specimen or a dwarf. At any rate, the latter has a suture with the first lateral saddles looking remarkably like an immature stage of those characteristic of robint. Grossouvre thinks this is the true ewaldi of Buch, but on the contrary it seems to me more likely that part of his ewaldi as given above belongs to robint. The peculiar ventral trend of the outer divisions of the first lateral saddles occurs apparently only in this species. Redtenbacher’s figures are of value in that they give information with regard to the young, showing that at a diameter of about 18 mm. the keel is prominent and continuous, as it is in later stages, the costee are well developed and uichotomous and have two rows of tubercles, one on each umbilical shoulder and a row on either side of the keel. It is also to be noted that the venter of this young specimen is more acute and the whole form more compressed than in the more mature stages. Locality: France and Austria. Age: Senonian. MeraTissoTiA Noposa n. sp. Hyatt. Tissotia haplophylla (pars) Grossouvre, 1893, Ammonites Craie supérieure, pl. 4, figs. 3, 4 (not fig. 5). The two specimens figured by Grossouvre have large nodes on the umbilical shoulders like those of haplophylla, but the costz are well developed at an age when these are absent in true haplophylla, as shown in Redtenbacher’s figure. The keel at the same stage is entire, whereas in haplophylla there is a row of tubercles. Locality: France. Age: Coniacian. 4% PSEUDOCERATITES OF THE CRETACEOUS. MeTATISSOTIA HAPLOPHYLLA (Redtenbacher). Ammonites haplophylla Redtenbacher, 1873, Abhandl. K.-k. geol. Reichsanstalt, Vol. V, pl. 23. Tissotia haplophylla (pars) Grossouvre, 1893, Ammonites Craie supérieure, pl. 4, fio. 5 (not figs. 3, 4). This form is compressed, but has heavy fold-lke costa and very stout nodes on the umbilical shoulder and ventro-lateral angles, the venter being similar to that of M. fourneli, but with a line of nodes instead of a con- tinuous keel. The French fossil quoted above may possibly be the same, but it has quite a distinct aspect, and the supposition of Grossouvre that the sutures will prove to be similar when those of the Austrian specimen are better known, is not sustained by the collateral evidence. Grossouvre’s figs. 3 and 4 of the supposed neanic stage of bis haplophylla are certainly quite distinct, having an entire keel and aspect allied closely to Metatissotia fourneli and robini and here treated as distinct under the name of Meta. nodosa. Locality: Austria. Age: Senonian. MeETaTISsoTIA EWALDI (von Buch). Ammonites ewaldi yon Buch, Abhandl. K. Akad. Wiss. zu Berlin, 1848, pl. 6, Tissotia ewaldi (pars) Grossouvre, 1893, Ammonites Craie supérieure, pl. 4, fi pl. 9, fig. 5). This species is very similar to Meta. robini, but, so far as known by the figures of Grossouvre and others, these two species appear to be distinct in their sutures. Both species have the first lateral saddles deeply divided and the outer arms of these are shorter than the inner ones, but the outlines of these outer arms in this species are rounded, phylliform, undivided, and straight or parallel with the keel. In robini these outer arms are inclined toward the keel and the outlines are subdivided by marginal lobes in mature specimens, Locality: France. Age: Senonian. TISSOTIID®. 49 METATISSOTIA AURESSENSIS (Peron). Tissotia auressensis Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 17, pl. 18, figs. 4, 5. This is a cast of what is apparently an old shell. The form is not unlike that of Paratissotia grossouvrei, with a similar large umbilicus, and it might be considered as perhaps the gerontic stage of this species, but the sutures are so distinct that this supposition is not tenable. These have extraordinarily large and long phyllitorm saddles, and the first lateral saddle has a conspicuously trifid base. Locality: North Africa. Age: Senonian. METATISSOTIA SLIZEWICZI (Fallot). 2. Tissotia slizewiczi Grossouvre, 1893, Ammonites Craie supérieure, p. 46, fig. 25; pl. 7, fig. 2. Buchiceras slizewiczi Fallot, 1885, Ann. sci. géol., Vol. XVIII, p. 240, pl. 2, fig. ae This species, if correctly given by Grossouvre, has a young form which at a diameter of 41 mm. has a truncated venter, continuous keel, a line of small tubercles along each ventro-lateral angle beginning on the last volution at about this size, and also a line of nodes on the umbilical shoulders. The form at this stage is like that of Tissotia ef. fourneli Peron. The sutures are also similar in having trifid first lateral saddles and other saddles and lobes long and large. The three marginal saddles and lobes are much more completely developed, longer, and the first lateral saddles broader in consequence of this differentiation of the outlines. The nodes on both lines are much larger in the large shell figured and the keel persists. The umbilicus is also of good size, as in the species of Peron referred to above. Peron considers all of these forms to have occurred in the Senonian, and his evidence is very strong on this point. Locality: France. Age: Coniacian, base of Senonian. Q3——4 MON XLIV 50 PSEUDOCERATITES OF THE CRETACEOUS. PARATISSOTIA n. gen. Hyatt. Highly compressed smooth forms like the type of this genus, P. regularis and ficheuri, omit the characteristic nodose stages and more or less obtuse or flattened keeled venters of Metatissotia or else pass through them at an early stage, becoming later highly acute and smooth or at least without prominent nodes in their mature stages. In the two species examined they never have channeled venters at any stage. ‘The discovery of a hollow keel in the later stages of P. regularis would have caused me to separate that species from the other species referred to this group had their development been different and the structure of their keels also known. PaRATISSOTIA GROSSOUVREI (Peron). Tissotia grossouvre’ Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 17, pl. 16, figs. 1, 2. This is similar in aspect to P. ficheuri, but is less involute, the umbilicus being much larger and the sutures distinct. The first lateral saddles have denticulated outlines instead of the smooth, phylliform arms of P. fichewri. The young have not been examined, but the adult appears to belong to this genus. Locality: North Africa. Age: Lower Senonian. ParatissoTia ? THOMASI (Peron). Tissotia thomasi Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 17, pl. 13, fig. 3 (not pl. 16, figs. 5, 6). The type of this form is a compressed shell with very involute whorls and the zone around the umbilicus depressed and flattened. The venter, at least in advanced age, has a simple, not very prominent keel, unaccompanied by tubercles of any kind and sides almost smooth. The form is not sufficiently well known to be placed here without a query after the generic name. Locality: North Africa. Age: Base of Senonian. TISSOTIUD. 51 PARATISSOTIA FICHEUR1 (Grossouvre). Tissotia fichewri Grossouvre, 1893, Ammonites Craie supérieure, p. 35, fig. 17. Tissotia jicheuri Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, No. 1%, pl. 12, figs. 1, 2; pl: 18, fio. 2. Buchiceras ewaldi (pars) Peron, 1890, Moll. Crét. de la Tunisie, pl. 15, figs. 3-6. Buchiceras fourneli (pars) Bayle, 1878, Expl. de la Carte géol. France, Vol. IV, pl. 40, figs. 2 and 4 (not fig. 3). This is a very much compressed shell, with no channels on either side and no tubercles on the costae, which are simple and very slightly developed. The keel is prominent and acute, and the umbilicus is very small. The costee are shown by Peron in the side views of a young specimen having a diameter of 55 mm. and in a very old shell with diameter exceeding 115 mm. In both the coste are linear and straight, with only the outer half developed. A description of this last specimen, which is evidently very old, would have been of much interest, but it is not given. The very broad, low denticulated saddle occupying the extremity of the ventral lobe and the deeply divided denticulated first lateral saddles of this species, of which the outer one is bifid and the inner has a broad, phyllitorm base, are very peculiar, as are also the costae. The very globose fossil figured on pl. 15, fig. 8, by Peron in his Mollusques Crétacés de la Tunisie as part of his Buchiceras ewaldi 1s undoubtedly a distinet species, but the information given is too limited to enable one to refer it to any known species. The reference of part of B. fourneli Bayle to this species is given on the authority of Grossouvre. Bayle’s figures are handsome, but not very instructive. Locality: North Africa. Age: Base of Senonian. PARATISSOTIA SERRATA (Hyatt). Pl. II, figs. 7-11. Buchiceras serratum (pars) Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, p- 370. This is a fragmentary cast of more than one-half of an entire coil, without living chamber. The diameter without the shell is 37 mm. The outer volution measures 20 mm. at larger end, the umbilicus 4 mm., and opposite 52 PSEUDOCERATITES OF THE CRETACEOUS. side of outer volution from line of involution to venter is 17 mm. The shell reduces the diameter of the umbilicus to 3 mm. The cast of the outer volution is perfect only on one side. This is planoconvex and covered with regularly arranged cost, of which there are eight to half of a volution on the inner part of the whorl. The costz broaden and flatten outwardly, becoming sigmoidal in curvature and then bifureate, the branches bending well forward and rising into elongated swellings on the cast. These are about 3 mm. from the outer edge of the keel, and there are very slight obsolescent ridges beyond them, which, however, do not cross the smooth bands on either side of the keel. The venter on the first part of the outer volution, the third quarter, is subacute, but on the last quarter it is beginning to be rounded, the keel having disappeared. This shows that the shell was in the gerontic stage, and the approximation of the last two sutures also indicates the same stage. There is also the trace of a line, probably a line of involution, impressed’ upon this part of the outer volution, showing that the living chamber must have decreased very rapidly in the amount of involution, since it did not cover quite half of the sides on the third quarter and part of the fourth quarter. of the now exposed volution. The length of the absent living chamber could not be determined, but that it was much rounded and depressed on the venter and in an extreme stage of gerontic degeneration is highly probable. The sutures are more like those of Paratissotia fourneli, as figured by Grossouvre in his Ammonites de la Craie supérieure. The ventral lobe is, however, very short, broad, and opens widely, with two small, short, entire arms. The siphonal saddle is broad, prominent, and entire, with a hardly perceptible median marginal lobe or depression, which seems inclined to disappear in the gerontic stage. The first lateral saddle is large, as in other species of this group. On the third quarter of the exposed volution it is plainly only one bifid saddle, but on the fourth quarter the dividing marginal is deeper, and there appear to be two dis- tinct saddles, as in P. delfensis. The outer arni of the saddle shows a hardly perceptible median marginal, as in P. fowrneli. There are five other lateral saddles, all entire, and, like the first lateral, very short and extremely broad like those of P. fichewri, as figured by Grossouvre. The first lateral lobe is broad at the end and denticulated exactly as in Tissotia tissoti and Metatissotia ewaldi as figured by Douvillé, but it is very short and broad. The second laterals are smaller and also denticulated. TISSOTIID ®. 53 The remaining lateral lobes are like those of the same species, but very much narrower, and the second to the fifth hardly more than mere indentations. The dorsal sutures were seen only from above. The antisiphonal lobe was obviously very narrow at the base, but its length could not be determined. There are seven pairs of entire zygous dorsal lobes and saddles, the latter much narrower than the external laterals. The first and second lateral saddles are connected across the septum by broad ridges, so that the septum observed was convex externally and internally along the mesal plane, but concave along the center. The saddles on the dorsum and the corresponding external saddles were connected only by very slight ridges, and the intermediate surface of the septum was convex. The figures of sections show the broad globose, keelless form of the hepionic stages and perhaps of the earliest of the neanic stages. The siphunele is certainly véry small and the keel is solid when it first appears, as shown in figure. The disappearance of the siphuncle left me in doubt with reference to its structure in later stages. Locality: Cachiyacu, west side of Huallagua River, Peru. Age: Upper Cretaceous, probably Senonian. PARATISSOTIA REGULARIS n. sp. Hyatt. Pl. IIL, figs. 1-6. Buchiceras serratum Hyatt (pars), 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, p- 370. This species has a broad volution with a rounded venter until the shell reaches a diameter of 6 mm. See Mr. Stanton’s note, p. 65. SPHENODISCID®. 63 The first specimen is the only one with perfect young that I have seen, and is, therefore, a very instructive example (Pl. III, figs. 9-12). In ananepionic stage the innermost volution next to the large protoconch is rounded and followed by a volution still in the nepionic stage. This acquires an elevated venter and becomes more compressed and helmet shaped, but has nowhere a flattened or concave venter. The sutures were simpler than those of later age. The sutures on both sides had five divided saddles. he first lateral saddles were bifid on both sides, the second just beginning to be quadrifid, the third and fourth symmetrically trifid, and the fifth only hifid on the right; whereas on the left side the second to the fifth, like the first, were all bifid. The volutions in section were similar in outline to the adult, having the same highly involute aud almost pear- shaped section and acute venters. Neither of these specimens showed the living chamber. One specimen (Loc. 582, U. 8. Geol. Survey, Pl. V, figs. 1, 2), when compared with more typical forms, shows, in what is probably the mete- phebic substage, the outer fold-like costee as in the gerontic stage of others. The diameter of the cast, without the shell, is about 118 mm., partly esti- mated. The last of the outer volution measures 60.5 mm., the umbilicus 8 mm., and the opposite volution from line of involution to venter measures about 49.5 mm. The acuteness of the venter decreases on last part of this volution, but does not become blunted and rounded as it does at the corresponding size in the typical form. The sutures of the last five septa show gradual approximation, and in the closer approach of the last two there are indications that the specimen was beginning its gerontic stage. The living chamber was broken away, but the marks of the umbilical parts showed that this had extended at least one-fourth of a volution farther on the sides. The inner line of tubercles was becoming wider apart, and together with the venter and sutures, also indicated that the gerontic stage was begun or was about to begin, and had been perhaps nearly completed in the now absent living chamber. The sutures, it will be understood, always represent a later stage than the parts of the shell on the inner surface of which they are found. The sutures have short phylliform saddles and broad lobes, and are well separated from each other and approximate only near the umbilical shoulders. They were 64 PSEUDOCERATITES OF THE CRETACEOUS. more perfect on the side opposite to the one figured. The first lateral sad- dles are trifid, the second, third, fourth, and fifth are bifid and phyllitorm; the remainder are similar to those of the inner columns of others of this species, but are perhaps somewhat simpler in outlines. The exact number was not ascertained. On a fragment of what appeared to be the same species from the same locality, there were thirteen saddles at a diameter of 60 mm. from line of involution to venter. This was a cast, and slightly abraded on the venter. The ventral saddles were much worn and the first lateral saddles were entire, except for a faint median marginal in two sutures. The remaining lobes and saddles exactly agreed with those of the ephebic stage of the first specimen described, except in being a trifle longer. ‘There were five divided saddles, as in other specimens. One of the figures of Amm. pedernalis given by Binckhorst in the monograph quoted above was taken from a Texas specimen supposed to be identical with von Buch’s species. The specimen was in the Museum of Stuttgart, and was said to have come from Rio Bravo del Norte, Texas, and to have been collected by Schott. This figure is identical with the larger varieties of this species which retain the acute venter until a late stage of development. This same specimen was refigured by Bohm, as above quoted, and properly named by him. Except in being somewhat older and large, it is identical with the fossil figured on Pl. III, fig. 15 (septum), and Pl. V, fig. 3. The first lateral saddles are, however, bifid, the second trifid, the third to fifth bifid, whereas all the saddles in sutures on Pl. II are bifid, and this holds in all the sutures on this volution in this fossil. Even in the close approximation of the sutures this is similar to Bohm’s figure and also in the way in which the inner line of nodes trend outward on the latter part of the volution. ; A fragment in the collection of Frederick Braun, of Brooklyn, N. Y., is labeled as from rotten limestone grit, Brooksville, Noxubee County, Miss. The diameter of side is 55 mm. The inner line of nodes still remains somewhat elongated; the outer line is superseded by broad folds. The fine surface of this cast shows that the shell had sigmoidal, and sometimes dichotomous, coste and ridges on the outer convex half of the volution, but that it was smooth and decidedly concave on the inner half. The first lateral saddles were trifid, then four bifid and nine entire.. There were ten entire dorsal saddles at the same age, with lobes ‘like those of the exposed SPHENODISCID ®. 65 sides. Unluckily the antisiphonal lobe was not exposed by excavation, and therefore it was not considered necessary to draw these curves. This species is very instructive, since its external characteristics are well marked and they show that the amount of involution, the general outlines of the lobes and saddles, and the number of divided saddles remain very con- stant, while the trifid or bifid outlines of the larger saddles are variable. These minor details of the saddles, and of the lobes also, depend on the relative growth of marginals and may vary at different stages of growth or on the opposite sides in some individuals or in different individuals. The number of septa may also greatly vary, thus in Bohim’s and the fossil figured on Pls. III and V they are 5 mm. apart near the center; in Braun’s they are 9 mm. distant at about the same age and the saddles are much longer. Another specimen from the same collection is given on PI. VI, fig. 6, and this although closely associated with S. lobatus, and apparently at first sight the young of that species, has all the external characters and the sutures of pleurisepta. The fossilization is in the peculiar yellow limestone, with iron incrustations of the specimens of Jobatus from the same locality. It is of course possible that this specimen may be the young of lobatus, which I have never seen of as small size, but in any case it is identical with plewrisepta of the same age, which has an acute venter on the outer volution and sutures like those of Pl. III, fig. 15. There are five bifid saddles on the right side at the point where that side is about 30 mm. broad, and on the left side, where 20 mm. broad, the fifth saddle shows the faintest possible beginning of a median marginal division. Locality: Near Laredo, Rio Pecos, and near Eagle Pass, Tex.; Brooks- ville, Noxubee County, Miss.” Age: Eagle Pass beds, Upper Cretaceous. «The following note was contributed by Mr. Stanton: “Tt is pretty well established that Conrad’s specimens were not collected near Laredo. It is probable that they came from the neighborhood of Eagle Pass, where the species is abundant. It has been collected by Geological Survey parties from localities from 1} to 18} miles southeast of Eagle Pass. “ See Mantelliceratide. METOICOCERATID ZX. ALe systematically handled with due regard to the collateral evidences, deduci- ble from the later stages of development and the obvious relations of the adult and even senile stages. Thus in the present case, while the young would place this genus entirely outside the pale of the Heinziidee, the later neanic and the ephebic stages and old age and sutures show them to belong near that group. The peculiar elongated crestlike tubercles, the coste, and finally the sutures are of the Pulchellian type. When these later stages are allowed their full weight, it is then seen that the development shows Metoicoceras to be the descendant of some common form from which Carstenia tuberculata and Heinzia provincialis are also descended. It is also apparent that this must have been either similar to or identical with some species of the coronate genus described here as Cheloniceras. The coronate young of Metoicoceras are not reconcilable with the young of Heinzia nor any other form of this family, so far as known. The develop- ment of Heinzia differs in the suppression of the coronate stage and of the sextuberculate stage and the appearance of the approximated lines of tuber- cles on the venter of the Heinzian type by a tachygenic mode of develop- ment common in this group. The difficulty of reconciling the development lies in the fact that the outer rows of tubercles appear later than the ven- trals and are not developed, like those of Metoicoceras, from a primitive row preceding the ventrals in development. This may be a case of what Cope has called retardation of development, but if this is so, the effect is really to accelerate the appearance of the Heinzian characteristics of the venter. The sutures of the entire groups of Cheloniceratidze and Mantelliceratidee are of the same type. The number of lobes and saddles is much more limited than in Heinziidze or Pulchelliidee, both on the dorsum and externally. The outlines also are excessively complex, with a certain ragged look due to their long, subdivided marginals, and also apt to be asymmetrical or trifid rather than bifid. There is also a noticeable absence of simple entire sad- dles und lobes in the umbilical region. Comparison of the sutures of Metoicoceras with those of Heinzia or Pulchellia shows at once resemblances that are quite close enough to place swallovi in the same group with Heinzia, and the sutures of Metoicoceras are especially close to those of Carstenia? tuberculata. The development, being irreconcilable with that of any form of Heinziide or Pulchelliidee, shows that the genus can not be placed in either of these families without confusing the picture of their systematic and genetic relations, so far as now known. Ih ite PSEUDOCERATITES OF THE CRETACEOUS. MEroIcocERAs SwaALLoyi (Shumard). Jel DO thes, (ee Tea GOR, sires tl Ps JRL DE ategsy Te Ammonites swallovi Shumard, 1859, Trans. St. Louis Acad. Sci., Vol. I, p. 591. So far as I have been able to see, this species has not been previously figured, but that described below as whitei has been the one selected as the typical form of swallovi. The following quotation from Shumard’s description shows that while he had in hand perhaps both of the species here described his remarks seem to apply more decidedly to the one selected as swallovi rather than to its less -prominently nodose and more complex companion. Shumard states “dorsum [venter] flattened, transversely ribbed, nodose-bicarmate; * * * umbili- cus deep, exhibiting about one-third of each of the inner volutions and about as wide as one-half of the width of the last volution.” If he had in hand such a specimen as the one he mentions as being 6 inches in diameter, and it was a representative of whitei, this large umbilicus would be just about in this proportion, but it would be inapplicable to an ephebic stage as a young specimen of this species. If he had had a specimen of M. swallovi, the large umbilicus would have been found in the neanic and ephebic stages in about this proportion. Shumard’s other remarks apply also about equally well to either species, but the sutures, as described by him, point out quite clearly the typical form. ‘Dorsal saddle almost double the width of the superior lateral lobe and divided into two unequal branches by a short subconical auxiliary lobe; the dorsal [outer] branch having three small notches, while the inner one is rounded and has usually only a single small notch at its internal border.” Such simple outlines as these occur only in the forms here referred to as swallovi, and one of the specimens (Pl. XIII, fig. 2) came from Grayson County, Tex., the typical locality quoted by Shumard. The young figured (Pl. XI, figs. 7-15) and the sutures (Pl. XJ, figs. 18-23) were taken from a specimen found in a piece of the matrix cracked off from the specimen shown in fig. 16 and are quite likely the young of this species, but it is probable that at this age the differences are slight between this species and white7. Three specimens were obtained from this piece of matrix. That to which figs. 12, 13 belonged reached an older METOICOCERATID ®. 119 stage than figs. 14, 15, and the last node near the umbilicus on this was considerably larger than the preceding nodes, indicating that this young one belonged to this species. The breadth cf side at this age was about 9 mm., the transverse diameter about 6 mm. The breadth of the side at the base of the living chamber, which was badly crushed farther on, in fig. 16 is 20 mm., while the diameter between the tubercles is 16 mm. The young volution was quadrate in form, the sides parallel, whereas in the specimen represented by fig. 16, as may be seen in fig. 17, the lateral zones are highly inclined and the venter much narrower than in the young. In the fossil shown on Pl. XII, fig. 2, the breadth of the side at the third suture is about 33 mm., the transverse diameter between the coste being 23 mm. The outward inclination of the sides in this specimen was not so great as in the fossil represented by Pl. XI, figs. 16, 17, even at the same stage, and the nodes near the umbilicus were apparently not quite so prominent. Besides the marked prominence of the nodes and their dichotomous costz, the living chamber in the young (figs. 14, 15) is clearly nearly three- fourths of a volution in length, while in the later stage it appears to be in part complete and to be one-half of a volutionin length. It is obvious that this species becomes more compressed with increasing age, and has a much narrower venter and less transverse diameter in proportion to the ventro- dorsal than in the young. The protoconch has an arcuate venter (Pl. XI, figs. 7-10) and rounded dorsum, with subangular bend as the outline approaches the opening of the conch. This opening, doubtless once the aperture of the protoconch, is much depressed or broad transversely and continues to have this form throughout the ananepionic and metanepionic substages. The elevation of the venter begins in the second volution, fig. 10, but the form remains smooth and the sutures goniatitic until about the fourth volution.* Then nodes begin to appear on the ventro- lateral angles and the venter becomes broader in consequence. The venter is smooth at this substage, the first of the neanic substages. In the next substage, about one-half of a volution later, fig. 14, the costee become more prominent near the umbilici and wrinkles appear on the venter, each accompanied by a pair of tubercles. In the next substage, which was not seen, it is probable that these ventral costze become connected with the lateral ones and equal in number to them, and nodes appear on the inner «This was guessed at. 120 PSEUDOCERATITES OF THE CRETACEOUS. ends of the lateral costae and there fuse into more or less dichotomous forms. This fusion is not as complete in the fossil shown in fig. 16 as it is in the one shown in Pl. XIII, fig. 2, at a later age. The sutures seem to follow about the same steps in progress of devel- opment as the external characters. Fig. 11 gives an enlarged sketch of ezecum, which seems small in this specimen and which opens into a large siphunele, whose parts could not be studied any further than is visible in the drawmg. Although every effort was made, and this specimen was remarkably clear and transparent, nothing definite could be made out beyond the cecum. It is certain that the dark color of the wall of this body has no posterior prolongation or prosiphonal continuation. The second septum, beginning the sutures of the metanepionic substage, had unquestionably a divided ventral lobe, as given in fig. 10. This was estab- lished by many repeated observations. There were, as usual, but two broad goniatitic saddles of the Tornoceran type on either side and one broad lateral lobe on each side, with a distinct saddle at the line of involu- tion. Iwas not able to detect any depression, such as I have previously described in other forms as an embryonal umbilicus, occurring at the begin- ning of the true conch. In the paranepionic substage the suture becomes distinctly divided on the sides into two broad saddles, with a lateral lobe and a lobe at the line of involution on either side, and during this substage the dorsal suture assumes finally the aspect given in fig. 21. The sutures (figs. 18-20, 22) belong to the neanic stage, represented in figs. 12-15. They show the usual mode of division common in Ammonoids of the Jura and Cretaceous, the incoming of auxiliary inflections ‘on the primitive second lateral saddle and the primary bifid division of the first lateral ~ saddle and first lateral lobe, the entire aspect of the siphonal saddle and its subsequent bifidity. Fig. 22 of Pl. XI shows the peculiar prolecanitean aspect of the dorsal inflections before the end of the neanic¢ stage, and illus- trates my previous statements with regard to the retention of ancestral characters by these internal sutures. Fig. 23 of Pl. XI and fig. 1 of Pl. XIII are of very nearly the same age, and give the beginning of the ephebic substages. The latter show that the primitive median marginal lobe of the primitive dorsal saddle becomes the large marginal dividing the full-grown first lateral saddles. This suture also shows that the second lateral saddle has a trifid termination in some specimens of this species. METOICOCERATID. 121 The sutures in the two specimens here described as swallovi are some- what abraded, but their details of outline are sufficiently well preserved in different sutures to enable one to see how much simpler they are than in M. whitei. his simplicity of the marginals is not so great in some speci- mens as it is in fig. 2 of Pl. XIII, since in the suture (Pl. XIII, fig. 1) the second lateral is trifid and in fig. 13 the fourth lateral saddle is bifid. The number of inflections on the sides appears to ‘be less in this species than in whitei, five only being present on both sides, with saddles at the lines of involution; and in the fossil shown in Pl. XI, fig. 16, there is the same number, with a lobe at the line of involution. Locality: Grayson County, Tex.; Utah. Age: Colorado epoch. @ METOICOCERAS GIBBOSUM n. sp. Hyatt. Pl. XV, figs. 5-8. The single fossil upon which this species is founded could not be placed in any of the species here described under the same genus. It has stouter, broader volutions than any of these, and, instead of becoming more compressed as it grows older, continues the same rate of increase in the transverse diameters The involution is about the same as in M. swallovi, but there are no nodes on the umbilical shoulders at any stage, although the alternating longer coste reach to the umbilical shoulders. Their greatest prominence is at a short distance ventrad of the umbilical shoulder. The costations are like those of the oldest stage of whitei, i. e., regularly long, prominent costze alternating with short ones. The two outer lines of tubercles do not differ from those of other species. The sutures are intermediate between the simpler character of those of M. swallovi and the more complex outlines of those of M. whitei. The first lateral saddles and lobes have about the same general aspect as those of M whitei, but the auxiliaries are similar to those of M. swaillovi, except that the second lateral saddle shows small marginals and a tendency to division on its outer side, which has not been observed elsewhere. The third lateral saddle shows in some sutures of the left side a tendency to become divided, which is necessarily exaggerated in the drawing and which is entirely absent in many sutures, 122 PSEUDOCERATITES OF THE CRETACEOUS. both younger and older than the one drawn. he dorsal sutures could be seen only from above and in a fragment of the cast of the last camera, which is not included in the figures given. It was evident that the antisiphonal lobes resembled those of M. swallovi and Heinzia in being elongated and considerably telescoped into each other. The saddles also were similar, especially the first dorsals, which were narrow, long, phylliform, and deeply cut: into by the marginals, as in Heinzia matura. There was also a similar broad pair of second lateral dorsal saddles; these certainly had one marginal lobe and perhaps two, being perhaps trifid, but very flat on their bases. The remaining saddles were entire. There were apparently five saddles and four lobes on the right side and six saddles and five lobes on the left side, corresponding to the differences in number of the external auxiliaries on the same sides. The overlapping of the sutures is noticeable in this specimen, but whether it can be considered characteristic of the species is doubtful. The whole diameter is 85 mm. The last volution on the face of the septum from the center of the venter to the line of involution is 50 mm.; the ventro-dorsal diameter is 35 mm. The amount of involution at this point is two-thirds of the breadth of the side of the next inner volution, being 17 to 27 mm. The umbilicus, in consequence of the smoothness of umbilical zones and the nonextension of the cost internally, has a smooth, funnel-like aspect, entirely distinct from that of M. swallovi, although it is nearly of the same size and differs therefore from that of white? in being much larger as well as smoother. Locality: Texas. Age: Colorado epoch. METOICOCERAS WHITEI n. sp. Hyatt. Pl. XIU, figs. 3-5; Pl. XIV, figs 1-10, 15. Buchiceras swallovi White, 1875, Geog. and Geol. Expl. and Surv. West of 100th Meridian, Vol. IV, p. 202, pl. 20, figs. 1 a-c. Buchiceras swallovi Stanton, 1894, Bull. U. S. Geol. Survey No. 106, p. 168, pl. 37; pl. 38, figs. 1-3. The external characteristics of this species, in comparison with MM. swallovi, consist in more compressed volutions without such prominent nodes on the umbilical shoulders. They have nodes, but these are more a part of the costee and less prominent, the sides are consequently flatter than in swallovi. ‘There is a decided tendency in the Texas specimens to METOICOCERATID 4. 123 have the umbilicus smaller and the inner row of the two outer lines of tubercles elongated longitudinally and parallel with the outer rows. The sutures are more complex at an earlier stage and remain more complex throughout life as regards their marginal digitations. The first lateral lobes are also narrower and longer in proportion in the later stages than in swallovi, and the inflections are more numerous at the same age, being from six to seven, instead of five or six as in swallovi. The youngest stage seen (Pl. XIV, figs. 1,2) had a living chamber complete near the umbilicus and not quite three-fourths of a volution in length. Several specimens showed a completed living chamber near the umbilical shoulders and on the sides, and in adults it is much shorter, invariably one-half of a volution in length. The sides were smooth and flat at the beginning of the outer volution in this specimen. The costee appeared as shown in the figure and nodal termini were devel- oped on the last costation near the aperture. These were also present in the specimen shown in fig. 4, but, as may be seen in figs. 2 and 5, these were not prominent as in swallovi. The same is true of all of the seventeen specimens examined besides Pl. XIII, fig. 4 The elongated second row of lateral tubercles found in fig. 4 is also perceptible to some slight extent in the specimen fig. 7, but is absent in younger stages and is not present at any stage in some specimens. This second row of tubercles may be very slightly developed in some specimens, and the cost are also much less pronounced and the venters narrower than in those figured. ‘The other two specimens show a much stouter form with broader venters and more promi- nent cost. These can only be separated from true swallovi by their cost, flatter sides, and less prominent umbilical nodes. An old suture of this species is shown on Pl. XIII, fig. 5. This was the basal suture of a fragment of the living chamber of a fossil of about the same size, probably, and age as the one shown on Pia hoa The differences of this suture appear to be considerable when com- pared with Pl. XIV, fig. 8. The external characters of this fossil are equally decided, but the absence of the internal volutions and the variability of the sutures in this species does not justify the separation of this as distinct from white. The latter part of this living chamber and the whole of another larger fragment has huge fold-like coste that cross the venter, cutting it into waves. The costee are flat on the venter with abrupt forward edges. The ventro-lateral 124 PSEUDOCERATITES OF THE CRETACEOUS. tubercles and the second lateral row disappear on these coste. The decrease of the involution through shrinkage of the later diameters is greater in this than in the old age of the specimen shown on PI. XIII, fig. 4. Breadth of the side from line of involution to the siphonal saddle at the suture figured is 65 mm. The length of the living chamber on the outside or venter is 190 mm. and apparently complete, and the breadth 75 mm. In the specimen shown in Pl. XIV, fig. 7, the normal rate of increase is from 50 to 70 mm. in the same distance measured along the venter, and in the living chamber of the fossil shown on Pl. XIII, fig. 4, which is of the same length on the venter it is from 7) at the base to 80 mm. near the end: In both of these old specimens the length of the living chamber and decrease in the rate of growth was therefore about the same and about one-half of what it was in the fossil shown on Pl XIV, fig. 7, which was also an old specimen but was measured along the septate and therefore younger portion of the outer volution. The increase by growth previous to this must have been greater still, The broadening of the venter noticeable near the aperture (figs. 3 and 4), the spreading of the cost across the venter, and the loss of nodes are the same in all three of these specimens and show them to have entered upon the last or paragerontic substage or decline. The youngest suture examined in this species is shown in Pl. XIV, fig. 8, from the left side, and this has fully entered the ephebie stage and is already more complex than those of swallovt at a much later age. The corresponding suture on right side of the same specimen is similar, but the third lateral saddle was quadrifid instead of bifid and the fourth lateral was more distinctly bifid and phylliform. The matrix of this fossil from Elm Fork, Tex., was a gray limestone, whereas that of the specimen shown (fig. 9) was a red clayey limestone, but from the same locality. The suture was much older, but nevertheless had simpler third and fourth saddles on both sides of the outer volution. The position of the suture of the specimen shown in fig. 7, given in fig. 8, is indicated in fig. 7 by a straight line near the venter, but the sutures throughout this volution have the same outlines. This and fig. 10 are the most complex of the full-grown sutures observed in this: species. Fig. 10 was taken from the left side of Pl. XIII, fig. 4, and shows the outlines of about the same age as in PI. XIII, fig. 8. The shell was stripped from a part of the fossil shown in PI. XIII, fig. 4, also, and the corresponding suture on that side also observed. In this way it was found METOICOCERATID 2. 125 that the sutures on the two sides differed considerably. They were alike in their first and second lateral lobes and saddles, but the third lateral saddles were simpler on the right side, the side given in Pl. XIII, fig. 4, in having the marginals less distinct and the fourth lateral was entire instead of being bifid. The outlines internally were the same and there were seven saddles and seven lobes on each side, and saddles at the lines of involution. The differences between the more fully developed sutures on the left side, those of the right, and the oldest suture showed similar degenerations, the saddles becoming much shorter and broader in propor- tion and the marginals less distinct. The table on page 126 gives an account of the variations observed in the sutures. It will be observed that the first lateral lobe is quite generally bifid, but in the largest specimen (Pl. XIV, fig. 8) from Elm Fork, Tex., it is sometimes trifid. It is very obvious that this character- istic may be capable of two translations, some of the first lateral lobes in this specimen being made trifid by a slight enlargement and extension of the main terminal marginal lobe. The second lateral lobe varies from simple primitive form of bifidity to trifid without regard to age, but in most specimens it is bifid. The third lateral saddle is bifid or trifid without regard to age, but tends to become quadrifid in older stages. The fourth varies from entire to bifid or trifid, but in most cases is bifid or trifid. The fifth varies from entire to bifid or trifid, but is in most cases entire, sometimes bifid but rarely trifid. The number of lobes and saddles on the sides varies from 11 to 14 in the early ephebic substages and from 13 to 16 in the full grown. No. 6 is taken from a fossil with a notably stouter volution, more prominent coarser costz, and larger tubercles than any of its companions of the same size from the same locality, Elm Fork, Tex The whole diameter of this fossil when complete was probably not less than 63 mm. and the living chamber of the usual length, a little over half of a volution. Unluckily, like all others of this species, the aperture has been badly broken and the rostrum could not be observed. I at first thought this exceptionally stout and more coarsely ornamented specimen must be a different species, but the sutures, when laid bare, were identical with others here described as M. whitei, especially close to that given on Pl XIV, fig. 10. 126 (The number of saddles and lobes represents one side only. PSEUDOCERATITES OF THE CRETACEOUS. Variations observed in sutures of Metoicoceras whitei. mill, Dallas County, Tex.; No. 15 is from Utah; no locality is given for Nos, 11 and 12.] All except Nos. 11, 12, and 15 are from Elm Fork, Hortons Hanes, Second /|Third lat | Fourth | Fifth lat. Number eRe saaatiee Speci- sid sl First lat- s ee) “lof saddl ales mon, Jovimved.| giteh fertlobe| ope" aie | aude, | "are. (ARGJOEE on aor] ee of side. | , sum. mm. | | |(dueft._ - Bifid ..| Trifid .| Trifid .| Bifid ..| Entire. 11 1 J | { \ 2) Pl OX Sav Eee \Right i oa S00) a4 bonGl® so L6sCO@sleos80 2. (8) 11 @) ia wae | (Left... Bifid? - (2?) |...do ..| Entire?| (2) @) | ee: ween J } 1 { | a) "Right - | (2) @) Insole .),-do2 |) @) @Qy Left. ..| Bifid . 2 ..do ..| Trifid .| Entire. 14 Rae { S t \ <7 { ific (®) (0) 7 ntire \ (@) | PL xIVv, | Right - (2) (2) 2) (?) (2) @) | ea 8 jh |; Lett - “h wl © (?) () @) | ©) (?) \ (?) : AL (ent (2) | (@) | Brifid.¢) Trifid .) Trifid - 11 | | 5 ae 98 { @) (?) 2) @y @ (?) \ 2) SE \Right .|f ~ (2) | Bifid..| Trifid | Bifid..) Entire.) (?) i |(lueft- - - Bisidies peed Ome le Bit In| sa= dO leee cole 13 | Dogeses 4 \ 28 i 9 ? ° ° ? ? i (2) Right - a) (?) ?) (2) (2) @) | : ey is { (2) (2) | Bifid..| Trifid?| Entire. 11 \ © fae cing {rise é ‘ OG) ho @® (?) (?) Cama ey a ecu 31 j 2) (i) (?) (?) (?) (2) \ 10 | Pl xv Janae \Right - Bifid ..| Trifid .| Bifid ».| Trifid .| Bifid _. 13 Ao ‘3 d ee bo) (2) | Trifide) (2) (2) (2) @) ayes aE ee \Right - lL @ (2?) |...do.¢.| Entire.| Entire. 13? i 10 eal 35 Bifid ..| Bifid -.| Bifid ..|-..do -.|...do .. 16 |) @) |e. xv Kos \Right - - ie -do AOC erase eal tae 16 | fig 5 ; sLeft..- fake elsacGlo 54) Manel se ks) sae 6K 35 13 . ne eed 2 46GQ Seles CO 6-)bs-CO.@4|-5.60 5.65360 5. ‘es () Left - - .| -do - (2) 5616) slo HCl) sso oc 13? eee \ 45 { ? es I : ) @y bode cdl °(@ (?) saa (@) igh a ee fees \ 55 a Bifid do a BEG ntire 15 \ @) Pl. XII, Right - A610) Gel55-CO selec Cl. ¢.|) Wares |e oko <4 15 Hast ae ] r o te 1) ) ple emg Bi, XIV, fig. Left d d Bifid ¢.| Trifid .| Bifid 15 . e a6 oc) SollsqoO@lO aa 1 Cc. rind . 1 50 TAG { 65 { \ (2) ele Right i (?) @) (?) (?) @ (?) fig. 5 ; i en -o fBifid .. Bifid | 4-fid ..) Trifid - (2) Bi ae, ; “the aie Right - : td _.do ..|...do.9.| Bifid ..) Entire. 13 ; paeeg ee 2 figs. 7,8 s. 7,8. aBeginning to become quadrifid, i. e., having four minute marginal saddles by division of one of the bifid marginals, bWith a few minute digitations beginning to appear. c With three other very minute lobes, five marginal lobes in all. aDistinctly trifid. eObscurely trifid. fSome entire, others obscurely trifid. g With a number of small marginals just beginning. METOICOCERATID 2%. 127 In all of these specimens the first lateral saddles were of very nearly the same general character, decidedly deeply bifid, even in the youngest stages recorded, and with both arms subdivided by one or more marginal lobes; the second lateral saddles were also complex at all stages observed, and one small specimen not recorded in the table, with suture lines on the last volution running from 12 to 18 mm., showed the same facts. This has bifid first and trifid second lateral lobes, with quadrifid third lateral saddles on both sides. A bifid fourth is visible on the right side when the volution is less than 12 mm. ‘This same saddle with a bifid base is the only one visible in another fossil with a suture line of. about 8 mm. It is evident that the law of variation in the sutures is that lobes and saddles increase in ‘variability of outlines and in number progressively from the venter toward the dorsal lines of involution, the so-called auxiliaries or derivatives of the primitive second lateral saddles of the young being far more variable than the first lateral saddle. Locality: Kanab Valley, Utah; Elm Fork, Dallas County, Tex. Age: Colorado epoch. METOICOCERAS ACCELERATUM n. sp. Hyatt. Pl. XIV, figs. 11-14. I at first thought this to be the young of the species described by Whiteaves as Placenticeras liardense, but the figures given by him merely indicate that the venter had continuous cost across it. The condition of his fossils was, however, such that he did not see the venter, and this can only be inferred from the lateral aspect as given in his drawings. Apparently there were no tubercles on the sides in the full-grown specimen, and the umbilicus was about the size of that of M. whitei and not so small as in this species. There were no nodes nor prominent costz near the umbilical shoulder in this fossil, and the two outer rows of tubercles were much less prominent than in the preceding species. The venter in the first half of the outer volution resembled that of M. whitei at an earlier age on the first quarter of the outer volution of the specimen shown in PI. XIV, fiz. 1, but with less decided tubercles, and on the latter half of this volution it is changed as the venter is in the old age of M. whitei. That is to say, the coste that cross it are prominent and flat, but not channeled nor concave. The coste on the sides are not so prominent and coarse as in 128 PSEUDOCERATITES OF THE CRETACEOUS. whitei. There are more of them, and only the last begin to reach entirely across the sides. ‘There is a sigmoidal channel on either side that does not reach across the venter. This is a characteristic occurring also in M. liardense, but not in other species. This occurs close to what must have been the edge of the aperture, since the living chamber is considerably over three-fourths of a volution in length and was probably a little longer when complete. The black line shows the position of the basal septum of the living chamber shown on the opposite side of the fossil figured. Locality: Elm Fork, Horton’s mill, Dallas County, Tex. Age: Colorado epoch. HEINZIIDZ. The members of this family are easily distinguishable from the typical Pulchelliide by the possession at some stage of elongated, usually double, but more or less connected tubercular terminations on the ventral ends of the lateral costee. All of the forms so far known have coarser and more complete lateral coste than are usual in Pulchelliidee, and there is, especially in primitive forms, a tendency to the development of stouter volutions, with less involution and consequently wider umbilici. The average size is larger, and the development is very distinct in all forms, so far as known. The young are stouter, less involute, and have costs con- tinuous across the venter. The tubercles appear upon these coste in two lines of single tubercles, and then subsequently two rows are developed upon the outer sides of these that remain more or less closely connected. The lateral coste are similar to those of Pulchelliidze, but sometimes a median or an inner row of tubereles or both appear in the later stages. The ventral channels are apt to be real channels furrowing both the coste and the intercostal spaces on the venter, and in the young and in primitive forms are apt to be narrow and smooth. The sutures are similar to those of Pulchelliidee, but as a rule have fewer and larger saddles and lobes, and the outlines more complex at the same comparative age, judging from the size of the casts. The development is so distinct from that of Pulchelliidze in some species of Heinzia that if it were not for the fortunate accident that placed one specimen of Heinzia matura in my way, I could not have offered any rational suggestion as to the true relations of this family. The development of Heinzia matura, however, shows, as stated below, a form that in the HEINZIID®. 129 young is involute, smooth, and compressed with a rounded venter as in the young of Pulchelliide. Then it has a faint line of ventral tubercles and flat venter followed by a true Pulchellian stage with channeled venter bordered by single tubercles. In other words, at this age the species is like Pulchellia except that the tubercles are not elongated crests. The ephebic stage shows the usual terminal double row of tubercles of the Heinziide. The conclusion from this evidence is that the Pulchelliidee probably arose from Heinzia or some very similar form through the increase of compression and involution and from the prolongation of the smooth larval stages, the suppression of the preliminary lines of ventral tubercles in the young and the tendency in later stages to suppress the second lateral lines of tubercles. This inference acquires some support also from the fact of the earlier appearance of Heinziidz in the Neocomian. We can in this way account for the communal resemblances of these two families in their adult forms, costee and sutures, but it must be borne in mind that the evi- dence upon which this inference is based is not by any means complete. The evidence with regard to the connection and genesis of forms is less complete than in the Pulchelliidze, but the following diagram gives the apparent relations of the genera so far as the ontogeny at present known indicates these: Metoicoceras Gerhardtia Carstenia | | = | Heinzia | Cheloniceras HEINZIA Sayn. Sayn® defines this genus in the following terms: ‘‘Les espéces qui se rattachent aux Pulchellia subcaicedi et provincialis sont nettement caractér- isées par une ornementation vigoureuse, visible dés les towrs embryonnaires, un accroissement en général moins rapide, des sutures le plus souvent trés éloignées les unes des autres et remarquables par le grand développement en largeur des selles et l’amoindrissement des lobes trés ¢troits et peu découpés.” The group described by Sayn under this name is obviously a «Amm. du Barrémien du Djebel-Ouach prés Constantine: Ann. Soc. d’ Agriculture de Lyon, 6th series, Vol. III, 1890, p. 151. MON XLIV—03——9 130 PSEUDOCERATITES OF THE CRETACEOUS. composite of several genera distinct in their .development and in° their sutures from any form of true Pulchelliide and also differing decidedly from each other. The species here mentioned as H. sayni is assumed to be the type beeause it is one of the first two species mentioned by this author and is the first one of these figured. His Pulchellia subcaicedi appears to me to belong with Pulchellia caicedi (Karsten) in the genus Carstenia. Heinzia saynt Hyatt. Pulchellia provincialis Sayn, 1890, Ann. Soc. d’Agriculture de Lyon, 6th series, Vol. II, pp. 165, 166; pl. 1, fig. 16; pl. 2, fig. 7. This is neither the species figured by d’Orbigny nor that given by Nicklés, but a dwarfed, compressed form with fine tubercles and fine costze developed at a comparatively early stage. It is similar to true H. provin- cialis being less involute than corvoli. Locality: Djebel-Ouach, North Africa. Age: Barremien. Hernzia corioti Nickles. Pulchellia (Heinzia) corioli Nicklés, 1890, Mém. Soc. géol. France, Paléontologie, No. 4, p. 53, pls. 6, 7. This species and another, supposed to be allied to sayni, are both larger, have coarser ornaments and more complex sutures than the African forms, and broad channels like Gerhardtia. Locality: Spain. Age: Barremian. HeInzIA HEINZI Coquand.” Piulchellia heinzi Sayn, 1890, Ann. Soc. d Agriculture de Lyon, 6th series, Vol. II, pl. 2, fig. 5. This species has similar ornamentation, but much coarser than in H. sayni. The sutures are given, and these are not similar to those of Pulchellidee. Locality: North Africa. Age: Barremian. « Coronites is represented in North Africa by a small group of dwarfed forms having the develop- ment and general aspect of the more discoidal forms of Hoplites. The type is Cor. (Heinzia) coronatoides (Sayn). This form has a ventral channel, beginning at a comparatively early stage while the young are still highly coronate and the costz dichotomous on the venter. These spring from singie nodes cn the latero-vyentral angles, which are coincident with the umbilical shoulder. These subsequently HEINZIID®. 131 HEINZIA HISPANICA n. sp. Hyatt. Pulchellia (Heinzia) ef. provincialis Nicklés, Mém. Soc. géol. France, Paléontologie, No. 4, pls. 6, 7. Nicklés’s figures give a species with smaller umbilicus and a shallower, wider channel turrowing the costze only, as in Pulchellia. The costz have more prominent nodes and are more prominent on the venter, which is crossed by them and cut up into waves as in Pulchellia. There is one specimen in the Museum of Comparative Zoology, prob- ably from Escragnolles, that I have labeled Heinzia atf. hispanica. It differs from this species only in having more involute whorls and perhaps somewhat coarser costee and possibly the sutures a little more complex. HEINzIA PULCHELLIFORMIS h. sp. Hyatt. This species, from the collection in the Museum of Comparative Zoology, has exactly the form and aspect of some of the typical species of Pulchellia, except that the costee are more prominent and cross the inner parts of the sides, and the outer row of tubercles has the broad, double character of those of the Hemzia group. This has no inner line of tubercles and has been considered similar to didayanus, which is a species of Nicklesia. Locality: Escragnolles, France. Age: Barrémian. HEINz1A PROVINCIALIS (d’Orbigny). Pl. XV, figs. 19,20; Pl. XVI, figs. 1-3. Ammonites provincialis VOrbigny, 1850, Prodrome de Paléontologie, Vol. II, p. 99. Pulcnelia provincialis Uhlig, 1883, Denksch. K. Akad. Wiss., Wien, Vol. XLVI, pl. 20, fig. 2. Assuming Uhlie’s figure to be taken from a species identical with VOrbigny’s, the specimen here figured is a true representation of this extend internally into lateral single costee and the nodes disappear. The costee become single on the sides or may remain dichotomous. The result is a form in some species that is almost an exact parallel with some forms of the Hoplitidee. The sutures are simple and have an immature aspect. The ventral is rather narrow and is divided by a small truncated siphonal saddle. The first lateral saddles are very broad, bifid on one side in H. hoplitiformis and trifid and still broader on the other. The first lateral lobes are narrow and trifid or bifid. Thesecond lateral saddles belong to the auxiliary series, and are much smaller than the first.and only slightly dentated, while the third and fourth saddles are entire. The second lateral lobe is very short and entire,and two other similar smaller lokes complete the lateral line. This description is taken from Sayn’s figures. 132 PSEUDOCERATITES OF THE CRETACEOUS. species. It has the narrow, deep, smooth ventral channel, which is also shown in Uhlig’s figure, with the same peculiar abrupt ventral terminations to the costae with forward bend on the edge of the channel. The venter is not cut up into waves by the crossing of the coste as in H. pulchelliformis. The channel, in fact, is deeper than the depressions between the coste, and the ridges that guard it on either ridge give a pointed aspect to the forward terminations of the costz. This is also observable in Uhlig’s figure. On splitting this specimen I succeeded in exposing three substages of neanic age. The first substage showed famt costz that crossed the rounded venter, the form being at this time rounded, with gibbous sides and open umbilicus. Then faint tubercles appeared, the venter still remaining rounded between them. These tubercles in the next substage became more prominent, and the venter between them became flattened. The cost became more prominent at the same time on the outer half of the side and made a slight forward bend on to the venter. Soon after this a very faint, narrow, linear depression indicated the beginning of the ventral channel. I was not able to discover at what age the second range of tubercles began to come in nor their exact position. The volution is gibbous on the sides throughout these early stages and is a rather stout young form with an open umbilicus. Locality: Escragnolles, France. Age: Barremian. | HEINZIA MATURA n. sp. Hyatt. Pl. XV, figs. 12-18. This species is allied to that described above by Sayn. It is similar in its compressed form, in the amount of involution and in the broad ventral channel, and in having a row of tubercles on the umbilical shoul- ders. The costz are, however, much broader and have the double external termination of the group of Heinzia. This termination is, however, not distinguishable on the earliest part of the outer volution, but is well devel- oped on the third quarter of this volution. This termination is seen in this specimen to be a modification of the ends of the costze, and it is not due to the approximation and coalescence of an inner row of tubercles with the outer row. The shell is preserved on one side of this specimen and shows HEINZIID®. 133 the same markings as on the cast. The young is much flatter and increases faster in the abdomino-dorsal diameters than in other species of Heinzia and remains smooth until a later age. The tubercles appear also later on the venter, and there is a flat ventral zone for a more prolonged stage than in H. provincialis, and the yentral channel appears later. The umbilical tubercles appear on the last volution figured and are at first single. Then they probably become [double] by the development of two other rows of tubercles near the ventral lines, but this was not actually seen on the specimen. Locality: Escragnolles, France. Age: Barremian. HEINZIA OUACHENSIS (Coquand). Pulchellia owachensis Sayn, 1890, Ann. Soc. d’Agriculture de Lyon, 6th series, Vol. II, p. 157, pl. 1, fig. 15 (not fig. 14). This species, described as a Pulchellia by Sayn, is an involute com- pressed form probably in the same genetic group with H. matura. This is shown by the ventral channel and costs and tubercles on the umbilical shoulders. It has not the broad double terminations of the costze observed in H. matura. Fig. 15 is probably a true Pulchellia, and is cited under that generic name as P. kiliani. Locality: Djebel-Ouach, North Africa. Age: Barremian. . CARSTENIA n. gen. Hyatt. This remarkable group has, as shown by Karsten’s figure of Carstenia lindigi in the latest neanic or early ephebic stage, coarse costee with double terminations becoming dichotomous at the middle lateral line and having a line of nodes at their junctions. These are continued later on the singie costee when these appear. The arising of the double line of outer tubercles close together on the ventral line is also shown in this figure. The form is stout in the type mentioned above and similar to that of Heinzia provincialis, but in the Carstenia (Amm.) caicedi Karsten it is more involute and com- pressed. The ventral furrow in Carstenia lindigi in the young is narrow and similar to that of Heinzia, but later it broadens and becomes similar to 154 PSEUDOCERATITES OF THE CRETACEOUS. that of Gerhardtia. This occurs in an earlier age in Carstenia caicedi. Descriptions are wholly taken from Karsten’s figures.“ CARSTENIA SUBCAICEDI (Karsten). C. subcaicedi (Karsten) is described by that author as having heavy coarse coste bifureating like those of caicedi and, if his small figure represents the young or a primitive dwarfed form of this group, it shows how very distinct its development must be as compared with that of other genera. CARSTENIA? TUBERCULATA 0. sp. Hyatt. C.? tuberculata (Pul. provincialis Gerhardt)’ is described by that author as identical with lindigi Karsten. It is, however, less involute, and, although having similar quadragonal volutions, has costz like those of Gerhardtia and there is no median lateral line of tubercles. The sutures are more like those of Metoicoceras than of Heinzia provincialis. It is possible that the development of this species may show it to be more nearly related to Metoicoceras than to Carstenia. It has, however, the peculiar channeled bases of the second row of tubercles on either side that have been found so far only in this last-named genus. All of these have been supposed to be of Barremian age. Its characteristics seem also to ally it decidedly with such forms as Heinzia provincialis, and to indicate a common origin for all of these genera in some primitive form with similar but more tuberculose volutions. It is obviously a more primitive form than Heinzia, which has more compressed and often more involute shells and retains in its latest stage the form and aspect of the young of H. provincialis and of the earlier neanic stage of Metoicoceras swallovi. The resemblances to Gerhardtia are also close, as may be seen on Gerhardt’s plates, and its form is similar to the young of Carstenia caicedi as figured by Karsten. These affinities and its obviously primitive larval characteristics show it to be the nearest approach yet found of the probable genetic ancestor of the Heinziidee. aGéol. de ’ancienne Colomb. Venez. Nouy. Gren. et Ecuador. Berlin, 1886. >Kreidef. in Columbien: Neues Jahrbuch ftir Min., Geol., und Pal., Beil.-Bd. XI, 1897-98, p. 152, pl. 2, fig. 8. HEINZIID ®. 135 CaRSTENIA GALEATA (d’Orbigny). Ammonites galeatus VOrbigny, 1842, Voyage dans l Amérique méridionale, Vol. ITI, pl. 17, figs. 3-5 (not figs. 6, 7). Pulchellia caicedi Gerhardt, 1897, Neues Jahrb. fiir Min., Geol., und Pal., Beil.-Bd. Xa; p: L51, pl. 3, fig. 7. This species has a form, costz, ventral channel, and outer tubercles similar to those of C. caicedi Karsten, but having the single coste: appearing later, the double outer line of tubercles disappearing at the same time, and no median lateral line of tubercles apparent in d’Orbigny’s figures. The double outer tubercles are observable in figures given by d’Orbigny at the beginning of the outer volution and are quite plain upon an excellent cast of this fossil from Chile in De Koninck’s collection in the Museum of Comparative Zoology. Figs. 6 and 7 of d’Orbigny are true Pulchellia, not the young of this species. Pu. caicedi Gerhardt has exactly the form and aspect of the next younger parts of the volution figured by d’Orbigny and observable on the last mentioned. GERHARDTIA n. gen. Hyatt. The near alliance of this genus with Heinzia becomes apparent upon comparison of the type Gerhardtia galeatoides (Karsten) with Heinzia provincialis (V’Orb.) and Heinzia ? tuberculata. The umbilical characters are similar so far as the amount of involution and the general aspect is concerned, but the umbilical shoulders are more prominent, the umbilical zone is sometimes concave, broader, and the umbilicus deeper. The shell in the neanic and adult stage is more compressed and more involute than it is in Heinzia at the same age and also more involute than its own ephebic stage. The extreme decrease of involution in old specimens may also be noticed in these forms. The costz in the neanic stage are much finer and more closely crowded than in any genus of this group. The costee are similar, but the outer row of double nodes are absent or only very faintly expressed. The sutures are more complex in outline, but of the same general type. 'The form is more compressed, the venter more contracted, and practi- cally bounded by the elongated single nodal termini of the coste. The furrows between the costze cross the venter, cutting it up into flexures, and the ventral channel is very broad and affects the flexures only, not descend- ing to the level of the ventral furrows. 136 PSEUDOCERATITES OF THE CRETACEOUS. Besides the type mentioned above, this group contains Ger. galeatus (Karsten) (von Buch’s figure of this species is too poor for comparison), and Ger. veleziensis n. sp. Hyatt (Pul. didayi Gerh., op. cit., pl. 3, fig. 4). Amm. didayanus VOrb. belongs to genus Nicklesia. Amm. didayanus Karsten is probably a younger stage of the species figured by Gerhardt, and it came from the same locality, Velez. Similar species have been cited from other countries by Gerhardt, but these are unknown to me. All species are of Barremian age and found in Colombia or Chile. The sutures have been well figured by Gerhardt and are quite different from those of C. tuberculata and H. provincialis. PULCHELLIID-A. This family has highly involute compressed shells. The costee, when these are present, are acquired at a comparatively late age, and the tuber- cles, when present, are single elongated crests on the ventro-lateral angles of the coste. The coste usually cross the venter even when there is a channel on their outer surfaces. The sunken intercostal furrows that cross the venter also are not as a rule affected by the channeling of the coste. The sutures are of the same type as in Heinzia, but with somewhat more complex outlines. I have had no opportunity to examine the dorsal sutures. The primitive form is Psilopulchellia,* which retains the smooth keelless condition of its own young throughout life. This stage is transient in the development of other genera. In Nicklesia it is followed by a stage with a flat venter, and this is then followed by the development of lateral coste that cross the venter without tubercles or channels, or the latter may be developed directly from the previous stage. Subpulchellia has similar stages followed by a channeled venter due to the development of two slight ridges. Pulchellia develops lateral costee that cross the venter, but these are concave on the venter and have lateral tubercular crests in place of the ridges of Subpulchellia. The intercostal furrows also cross the venter, but are usually convex on the venter between the coste. The tubercles have been universally ont erroneously spoken of as keels. They are really not «The author filed to seagate or cite any species belonging to Palenuienenin —T. W.S PULCHELLUID. 137 continuous at any stage and can not even be accurately described as ridges. The term carina or keel should be confined entirely to the continuous azygous ventral elevation. The term bicarinate is confusing and might be especially troublesome if-ocvasion should arise to describe a form having a really double or split keel. A further modification of the development takes place when a keel arises upon the smooth rounded venter of the earlier stages as in Psilotissotia. This form is apparently transitional to true Tissotidee, but these affinities disappear upon comparing the ontogeny with that of Tissotiidee, and especially when the relations of these to the flat ventered and keeled and chamneled forms of Pseudotissotia are recog- nized. The sutures of Psilotissotia are also decidedly Pulchellian and there are also transitional forms connecting it with Psilopulchellia. Lopholobites, so far as known, appears to be adequately accounted for as a retrogressive modification of Psilotissotia or some of the smooth forms with which it agrees in external characters. This suggestion requires, of course, to be tested by the comparative study of its development and that of the similar forms of this family.* The natural arrangement of these genera upon the basis of their ontogeny seems therefore to be as follows: Pulchellia | Nicklesia Subpulchellia Psilotissotia | paieelen align ate Penner es | Heinzia ! It seems obvious from the development of the young of most genera and the apparently full-grown Subpulchellia, and from the evidence of the sutures, that this group is closely related to Engonoceratidz. If this be so, the latter can be explained as a retrogressive form evolved from Subpulchel- lia as its most probable Neocomian ancestor. The supposed relations of some of the genera to Stoliczkaia are discussed under the head of Pulchellia. The parallelism between some of these forms of Pulchellia and the Hoplitidee is so close that it requires the evidence of their younger stages for their separation. It is closer than between this genus and any one of the Heinz- iidze, because of the presence of the line of double elongated tubercles in the latter. «The Pulehelliidze were not mentioned in my Cephalopod chapter in Zittel’s Text-book, owing to the accidental omission in copying of a page of the manuscript. ‘ 138 PSEUDOCERATITES OF THE CRETACEOUS. NICKLESIA n. gen. Hyatt. This genus has a prolonged smooth stage, followed by a costated stage, in which the coste are without tubercles and cross the more or less rounded convex venter without becoming concave. In some species, as in the type [N. dumasiana], the venter does not become decidedly flattened at any stage and the cost are very slightly developed. The following species, described and fully figured by Nicklés in his Paléontologie du sud-est de Espagne, can be referred to this section of the genus: Nick. moltoi, levyi, nolant, lapparenti. In other species the venter becomes markedly flattened during the latter part of the smooth stage, and the following species, described by the same author, are referable to this section: Nick. zeilleri, mallade, bertrandt. NICKLESIA ALICANTENSIS n. sp. Hyatt. Pulchellia (Stol.?) pulchella Nicklés, 1890, Mém. Soc. géol. France, Paléontologie, No. 4, p. 13, pl. 1, figs. 10, 11. This differs from d’Orbigny’s species in having regularly dichotomous, more or less sigmoidal costz, a wider umbilicus, less compressed form, and broader venter. The following species can also be included under this head: Nick. karsteni (Uhlig)” (pulchellus of Karsten). NICKLESIA LENTICULATA n. sp. Hyatt. Pulchellia aft. pulchella Gerhardt, 1897, Neues Jahrb. fiir Min., Geol., und Pal., Beil.- Bd. XI, p. 154, pl. 3, fig. 9. D’Orbigny’s species has several short costes between the longer ones, and the internal sections between the longer costations are smooth, whereas in both of the above the coste are crowded together and cover the sides of the shells. NIckLEsIa DipayaNna (d’Orbigny). Nick. didayana (@Orbigny), another species of this group, has been often misapplied to species having channels on the venter and lateral tubercles. aMém. Soe. géol. France, Paléontologie, No. 4, 1890. » Wernsdorfer Schichten, Denkschr. K. Akad. Wiss., Wien, Vol. XLVI, 1883. PULCHELLUD ®. 139 NickLesia pumasiana (d’Orbigny). Pl. XVI, figs. 6-8. Ammonites dumasianus VOrbigny, 1842, Voyage dans Amérique méridionale, Vol. IGUE Foy EE Fall alte This species is fully figured by d’Orbigny, and easily recognizable in case of large specimens. The French specimens that usually bear this name have been retained here with a question mark. The three examples that are in the Museum of Comparative Zoology are much smaller than the figures of the South American species, but are otherwise identical, and there are no young forms of the latter for comparison. The young specimen figured shows the development of the generic cost directly from a form with a rounded venter, without the intervention of a flat or concave venter. Locality: Colombia, South America; Escragnolles, France. Age: Neocomian. SUBPULCHELLIA n. gen. Hyatt. This becomes a distinct generic group, consistently with the principles advocated in this and other papers, because it represents a distinct grade in the evolution of the Pulchelliidz. Its permanent adult characteristics cor- respond to those of the transient condition of the neanic stage in the young of Pulchellia. Subpulchellia oehlerti (Nicklés) has a smooth involute shell, with a concave ventral area bordered by two ridges. The venter on casts is usually flat and has no definite ridges. The genus includes also Subp. fouquei (Nickles), and Subp. sauvageauw (Nicklés.) Subp. sauvageawi (Sayn) has lobes and saddles quite different from the Spanish form as figured by Nicklés, but whether it or Nicklés’s species is identical with Hermite’s it is not possible to state. Hermite’s original description and figure give no sutures. The shell as described in correction of the figure” has slight costations, present also in Sayn’s, as described but not as figured, and not mentioned at all in Nicklés’s description. The sutures of Nicklés’s specimens, one from near Constantine, Africa, and the other from Spain, are similar, but entirely distinct from those of Sayn’s figure. Until the suture of Hermite’s original or of a specimen from the «Hermite, Etudes géol. sur les Iles Baléares, Vol. I, 1879, p. 315, pl. 4, figs. 4, 5. 140 PSEUDOCERATITES OF THE CRETACEOUS. same locality has been investigated, it can not be stated whether Sayn’s or Nicklés’s species are really the same as Hermite’s. In these smooth forms the shells can not be relied on to show specific differences. SUBPULCHELLIA CASTELLANENSIS n. sp. Hyatt. Pl. XVII, figs. 1-5. The two specimens in the Museum of Comparative Zoology here described as the types of the genus and species are both smooth, compressed, highly involute shells similar to sawvageawi and others in aspect, but with denticulations on the auxiliary saddles not found in those species. The largest specimen is a cast 28 mm. in whole diameter, probably when complete about 40 mm. The inner edge of the living chamber shows on one side and this was about one-half of a volution in length. The suture figured was taken from the oldest stage of this specimen. The venter in this cast is plano-convex, and there are ridges on the ventro-lateral angles, but these are ridges because the lateral zones are faintly concave, consequently they are ridge-like toward the lateral aspects and not on the venter. The center of the venter has a raised line or pseudo-keel such as is figured by Sayn in his Pul. sawvageaw, and is not uncommon in species of Placenticeras. When the shell is present, the venter is slightly concave and it has the usual ventro-lateral ridges. The specimen figured (Pl. XVII, figs. 1-4) is somewhat younger, but shows a partially completed living chamber a little longer than one-half of a volution. Locality: Castellanes, France. Age: Neocomian. PULCHELLIA Uhlig. Uhlig designated three groups when he described this genus, the so-called bicarinated or true Pulchellia, the group with coste crossing the venter, equal to my Nicklesia, and those with a keel on the venter, the equivalents of the genus Psilotissotia. Nicklés recapitulates these facts and the observations of Douvillé, and joins him in referring the first group to Pulchellia, and also in thinking it possible that P. pulchella and some others may be referred to Stoliczkaia. Nicklés, however, retains these forms under the general name Pulchellia, and places the other generic names in brackets. PULCHELLID. 141 He has also traced some differences between the sutures of the different groups, but these are of such a nature that one does not get clear impressions from drawings, although those of Nicklés are remarkable for their excellence and full of instructive details. I unfortunately can not agree with these gentlemen with regard to Stoliczkaia. Neumayr® states “sehe ich mich genéthigt, eine Gattung fiir eine merkwiirdige kleme Gruppe von Ammoneen aufzustellen, niimlich, fiir die eigentiimlichen Formen der indischen Kreide, welche Stoliezka * * * beschrieben und mit den Hiallstatter Arcesten verelichen hat.” He then goes on to establish new names for the two Indian species considered by him to be distinet from Ammonites dispar VOrbigny, and the first of these, Stoliczkaia tetragona Neumayr or Amm. dispar Stoliczka,’ thus becomes the type of this genus. D’Orbigny’s figure and description of Amm. dispar shows a compressed involute shell with a volution in section like that of Nicklesia pulchella (?Orbigny), but the costee are narrow, and although they cross the venter they are quite distinct from those of this family. D’Orbigny’s species is an old shell of some other group, but is related neither to Pulchellia nor Stoliczkaia. Stol. tetragona has a quadragonal volution in section when full grown, venter depressed and slightly convex, sides same, umbilical zone abrupt and narrow. Ribs very prominent and sharp, reaching across the venter and side and having alternating shorter costz across the venter. Only one row of tubercles along the ventro-lateral angles in the young until in the neanic stage. These disappear in the adult. This is precisely the form and gen- eral aspect of some of the Mantelliceratide. For example, Amm. mantelli is either a member of this genus or a very similar parallel form. But none of these have costze or ornaments or channels like those of Mantelliceratide. Probably also the young are more or less distinct in development. Whether this last be true or not, the agreements of the adult sutures are not close enough to place such widely different structured shells as Stol. tetragona and Pulchellia pulchella in the same group, especially when there is close agreement between the latter and the younger stages of the typical P. compressissima and the suture lines are also similar. aZeitschr. Deutsch. geol. Gesell., Vol. XX VII, 1875, p. 931. d Foss. Ceph. Cret. Southern India, pl. 45, f. 2. 142 PSEUDOCERATITES OF THE CRETACEOUS. The keeled smooth forms were also referred by Douvillé and Nicklés and by myself in Cephalopods of Zittel’s Text-book under the name of Psilotissotia to Tissotide, but I am now satisfied that this is an erroneous view of their true affinities, and they are bere retained in the Pulchelliide. PULCHELLIA NICKLEsI n. sp. Hyatt, , Pulchellia compressissima Nicklés, 1890, Mém. Soc. géol. France, Paléontologie, No. 4, p. 8, pls. 1 and 3. This species is now, thanks to the drawings and descriptions of Nicklés, sufficiently well known so far as the neanic and ephebic stages are con- cerned, and it is not venturesome to say that in the still younger stages the venter must have been rounded and smooth like that of the group here named Psilopulchellia. The true P. compressissima WVOrbigny is a much thinner shell, with broader costze and narrower venter, the costal folds on the venter narrower and less deeply channeled. Doubtless the young are correspondingly distinct. The umbilicus is also narrower. Pulchellia schlum- bergeri Nicklés, Mém. Soe. géol. France, Paléontologie, No. 4, p. 38, pls. 7 and 8; Pul. columbiana (compressissima Gerhardt), also figured by d’Orbigny as the young of his dmm. galeatus in the Voyage dans PAmerique mérid- ionale, Pul. selecta, and Pul. hettneri also belong to this genus. Age: Barremian. There are two species described from Djebel-Ouach by Sayn, Pul. changarniert Sayn and Pul. kiliant n. sp. (Pul. (Heinzia) ouachensis, Sayn," pars). This last is distinct from Heinzia ouachensis Sayn in not having an inner line of tubercles and in its narrower ventral channels as well as in its sutures as described by Sayn. PULCHELLIA ComPREssissIMa (d’Orbigny). Pl. XVH, figs. 9-12. Ammonites compressissimus VOrbigny, 1840, Terr. Crétacé, pl. 61. This species is very peculiar and altogether distinct from the forms usually placed under the same name by authors generally. D’Orbigny’s figure is very similar to a specimen of the Krantz collection from Escra- enolles, the same locality as the shell figured by @Orbigny. The form of this cast is quite as much compressed and involute, the coste are present a Ann. Soe. d’ Agriculture de Lyon, 6th series, Vol. III, 1890, p. 155, pl. 2, fig. 15, not fig. 14. PULCHELLIID. 143 only on the outer half of the sides, the spaces between are narrow sulcations that cross the venter. The coste cross the venter with undiminished breadth and are channeled, but this channel is so shallow that I at first thought this must be the young of another species with very broad coste, Amm. catillus VOrbigny. The specimen described is just a little older than the shell figured as compressissimus by d’Orbigny and ribs begin suddenly to bend forward on the last part of the outer volution. Amm. catillus VOrbigny may also belong to this genus, but the characters of the young, which alone can determine this question, are not known. Locality: Escragnolles, France. Age: Neocomian. PSILOTISSOTIA Hyatt. This genus was unluckily considered by me when mentioned for the first time” as a member of the Tissotiide. In this I was not led by the opinions of Douvillé and Nicklés, but by what I then considered to be its true affinities. It has become obvious in studying Paratissotia, which approaches it nearest in form and in agreement of the development, that this is not a natural association. Nicklés’s plates also show that the sutures are similar to those of true Pulchelliide. They are involute forms, smooth, and compressed in the earlier stages and having at this time or all through the neanic stage a smooth keel that may in older stages become tubercu- lated. Costee may be represented by fine folds as in Psil. mariole Nickles, until a late age, but when they do appear they are heavy, fold-like, and sigmoidal. In this species also a median lateral line of nodes appears. If their real affinities are with this family, as they certainly appear to be now, they can be accounted for as direct derivations of Psilopulchellia which has evolved a keel. The intermediate aspect of species like Pul. defforgesi and haugi indicates that the shell did not have a flat ventral area at any stage, but was the direct outcome of the evolution of Psilopulchellia. This includes besides the type, Psil. chalmasi (Nickles), the following species: Psil. mariole, defforgesi, reigi, haugi, Nickles; Pul. defforgesi Nickles is described by him as having simply a sharp venter, but its affinity with mariolae would bring it into the group and the sharp venter may be merely due to the age of the example figured. «4 Zittel’s Text-book, p. 590. 144 PSEUDOCERATITES OF THE CRETACEOUS. LOPHOLOBITES Hyatt. LopHovositEes correaul (Nickles). Neolobites ? cotteaui Nicklés, 1890, Mém. Soc. géol. France, Paleontologie, No. 4, p. 54, figs. 36, 37; pl. 5, fig. 9. 9 This is a small, very involute, compressed, smooth form, with minute umbilicus and subacute venter. The external characteristics and sutures indicate this to be a retrogressive but more involute shell, allied to such species as Psilotissotia haugi, figured on the same plate by Nicklés. The sutures are entirely distinct from those of Neolobites, especially in the bifid character of the first lateral saddles and the greater differentiation of the inner saddles and lobes, which are more distinct from those of the outer part of the same sutures than in Neolobites. All of these discrepancies can be accounted for on the supposition that this is a retrograde form of Pulchellia. This also accounts for its small size when nearly outgrown, as in this specimen. Nicklés recognized the great differences between this shell and Neolobites, but hesitated to describe it as a different genus because of the great difference in its size. This fear was unfounded, since Neolobites could not have had a similar set of sutures at any age. Age: Barremian. KNEMICERATIDZ. The external aspect of the species of this group places them apparently close to the Buchiceratidz, but the sutures and the absence of a keel at all stages separate them widely. The first lateral saddles exhibit tendencies to division into several distinct branches, as in the Engonoceratide, and the outlines of the other saddles and lobes also are similar. ‘The division of the first lateral saddles is not carried so far as it is in Engonoceratidee. | The principal first lateral resulting from the secondary division of the primitive first lateral is consequently a broad solid saddle instead of the narrow first lateral of that family. Unluckily, the dorsal sutures were in no case exposed, and the conditions of fossilization in every specimen made excavation impracticable. The forms, both by their ornamentation and general development, are apparently more specialized and more complex than those of the Engonoceratide, and although the young was seen in only one example in a section the appearances were the same as in sections of species of the KNEMICERATID&®. 145 Engonoceratide. It has been therefore assumed that they had a similar stage in which the venter was concave and had continuous ridges on the ventro-lateral angles. KNEMICERAS Bohm.‘ There are but two lines of nodes on the sides and straight broad costee, bifurcating between them. The venter is broad and concave, the cost and nodes are opposite, and the venter is often transversely ridged between the nodes. The ventral lobes have the same shape as in Buchiceras and Roemeroceras and have similar truncated siphonal saddles. ‘The ornamenta- tion and form resemble these genera, but there is no keel at any age and the development is quite distinct. The young are not compressed as in Buchiceras, and the ventral zone is concave in an early neanic substage and remains concave throughout life. This shows similarity to Engonoceras and Placenticeras. The lateral lobes and saddles are similar to those of Engono- ceras, but the inner laterals are fewer in number and the first lateral saddles are more complicated. The divisions of the first may be counted as four or even five lateral saddles derived from a primitive first lateral. Until some one ontogeny is studied the correct enumeration can not be given. The young were seen in section. The rounded venter of the nepionie stage is succeeded in the neanic stage by a flat-ventered volution with quad- ragonal outline, and the concave venter appears in the earliest part of the ephebic stage. At this time the venter is very broad, the sides flat and obviously costated and tuberculated on the umbilical shoulders. Whether there were tubercles on the edges of the venter was not determinable. At an early neanic substage the umbilicus was open, the venter flat and broad, but narrower than the dorsal diameter through the umbilical shoulders, the lateral zones flat and convergent, the umbilical zones well developed. These characters and the broad costz and nodes of the later stages and the venter are similar to those of Pulchelliidee, but the division of the first lateral saddles in full-grown specimens and other sutural characters are dissimilar. The species discovered in the Cenomanian of Portugal appears to indicate that the real age of the fossils found at Mount _ Lebanon is Cenomanian, although, as may be seen by the context, I have doubts whether any of the latter belong to the fauna of the rocks in which they have been found. « Zeitschr. Deutsch. geol. Gesell., Vol. L, 1898, p. 200. MON XLIV—03 10 146 PSEUDOCERATITES OF THE CRETACEOUS. KNEMICERAS SyRIAcUM (von Buch). Pl. XVI, figs. 48. Amm. syriacus yon Buch, Abhandl. K. Akad. Wiss. zu Berlin, 1848, pl. 6. Knemiceras syriacum Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, p. 200. Von Buch’s figures of this species on his pl. 6 are excellent in all characters, but his suture line on pl. 7 is either erroneous or belongs to another form. One gerontic specimen is about 55 mm. in whole diameter, with living chamber nearly one-half of a volution in length. A smaller specimen, 45 mm. in diameter, has also reached into an extreme gerontic substage and has living chamber of same length. Von Buch’s specimen, according to his figures, was also in gerontic stage, but evidently somewhat larger, perhaps 70 mm., or thereabouts, when living chamber was present. This stage is indicated in one specimen as in von Buch’s figure by the approximation of septa in pairs as if the individual were only temporarily affected by weakness and then resumed the usual rate of increase. In one specimen the last sutures are irregularly spaced. The last three next to the living chamber are approximate. A slightly greater interval occurs between these, and there is a pair closely approximated, and apicad of this is a broader chamber and again a pair of approximated sutures. Apicad of this last pair there is a chamber broad on the venter but so narrow near the lines of involution that the sutures are crowded together on the umbilical shoulder. Apicad of this is the ephebic stage, with all sutures regularly spaced. The gerontic sutures are not always so irregular, and there may be as many as eight sutures showing more or less inequality in spacing, ending with a-series gradually becoming closer and eventually overlapping. The whole duration of the gerontic stage, including the living chamber, consists of about three-fourths of a volution. The lobes and saddles become shorter and the outlines simpler in this stage. Temporary approximation of sutures occurs often in the growth of these shells, and it is not always a sign that the gerontic stage has been reached, but when it is continued for some time, as in von Buch’s figure, and after a period of prolonged regu- larity in the width of the living chambers, it is obviously due to senility. There are no signs of a row of tubercles on the median aspect of the sides, and there are obviously only two rows of nodes with heavy fold-like bifurcated costee between. KNEMICERATID®. 147 The nodes continue to increase in length and size throughout life until in the latter half of the gerontic living chamber, when they show a decided and rapid decrease on the venter but persistently increase on the umbilical shoulders until near the end of this chamber. The living chamber was incomplete on the venter in all of these specimens, although in several it was complete near the umbilicus and somewhat over one-fourth of a volution in length. The first lateral saddles are bifid, having two broad arms, and both of these are again faintly bifurcated, these subdivisions -being minutely denticulated on the edges in perfectly unworn sutures, which can be found best by removing encrusting ostreans. In some specimens the second lateral saddle does not split up completely from the first, and instead of three principal lateral saddles there are but two, as shown in Pl. XVI, fig. 5. In others the division is complete, as it probably is in the later stage of the specimen shown in Pl. XVI, fig. 8. No specimen so far seen carries out the complete division of the remaining first lateral, although in some the median marginal lobe is quite long. It is a curious fact that all of these specimens—eleven in number and collected from five different sources— should have encrusting bryozoa and ostreans on the exterior of the cast and all more or less worn on all other parts of the surface. The lobes and saddles nowhere exhibit, and it is not likely that this species ever exhibited, the peculiar lobes and saddles figured by von Buch on his pl. 7. The entire suture seems to be incorrect for this species, whereas those given in pl. 6 are right so far as they go, although taken from the usual worn surfaces, of casts. Béhm’s figure, quoted below, is accurate, but belongs to an older stage than that figured in this work. The second and sixth lateral saddles are bifid, the seventh and eighth broad, flattened, and entire. There are marks upon unworn sutures indicating the presence of slight denticles on the edges of the principal saddles, but no such divisions and prominent marginals as in von Buch’s figure, pl. 7. The ventral lobe has two arms as in Engonoceras ; the dividing siphonal saddle is apparently flat, but when clearly defined it has a diminishing base divided by a minute siphonal lobe. Faint denticulations are present on both this saddle and the sides of the arms of the ventral lobe. The lateral lobes are club shaped, denticulated on the top, but entire on the sides near their base between the phylliform bases of the saddle. There are irregular trifid 148 PSEUDOCERATITES OF THE CRETACEOUS. outlines such as appear in Béhm’s figure,“ but there are also regular trifid bases to the first lateral saddles. The former arise from the irregular growth of the marginal saddles of the first or outer (originally bifid) arm of the first lateral saddle, making sometimes a simple triple division, and sometimes this outer arm itself becomes trifid, equally or more or less unequally, as in Bohm’s figure. The variation of the sutures is very considerable in this species, but there seems to be, so far as my material reaches, no sufficient grounds for the separation of specimens having trifid first lateral saddles from those having this part bifid. In fact one specimen shows early in the ephebic stage a bifid first lateral on one side and a trifid saddle on the other side of the venter, i. e., the two arms of the first lateral on one side are regularly bifid and on the other the inner arm is trifid and the outer arm bifid. Occasionally this outer arm may have four marginals. In one specimen the inner arm is bifid and the outer arm has three minute marginals. In one specimen again (PI. XVI, fig. 5) there are three arms, each regularly subdivided by a median marginal lobe. This saddle can perhaps be best described in general terms as having three arms derived from an original bifid form and usually preserving a record of this original form in the shortness of the outer marginal lobe as compared with the second marginal and also in the usually bifid outline of the base of the third or innermost arm. Often, as in Pl. XVI, fig. 8, the inner arm is sufficiently separated to be counted as a second lateral saddle. The specimen described by Hamlin in Syrian Fossils’ is fine only on one side and the supposed shell ‘‘the thin test almost entire” does not exist. Hamlin was misled by the smooth surface and the presence of a thin brown layer. That this is not the shell is shown by the sutures, which are somewhat worn, not showing the denticulations plainly. The living chamber is obviously nearly complete and is a trifle less than one-half of a volution in length. IJ have examined twenty-two specimens of this species and not a single one had even fragments of the shell preserved and many were incrusted with ostreans and bryozoa. There is no positive proof that these ammonites were living members of the fauna in which they were found, but there are obvious reasons in their aspect a4 Ueber Amm. pedernalis: Zeitsch. Deutsch. geol. Gesell., Vol. L, 1898, p. 199. ’Mem. Mus. Comp. Zool., Vol. X, No. 3, 1884, p. 11. KNEMICERATID&#. 149 and in the presence of these incrusting growths on the casts for consid- ering them as having been fossil casts when the incrusting animals erew upon them. Locality: Mount Lebanon, Syria. Age: Cenomanian. KNEMICERAS COMPRESSUM n. sp. Hyatt. Pl. XVI, figs. 9, 10, 15-18. Ammonites vibrayeanus Hamlin, 1884, Mem. Mus. Comp. Zool., Vol. X, No. 3, p. 12. The typical form of this species is separable from the variety subcompressum in full-grown specimens by the greater compression of the volutions, narrower venter, and less development of the nodes on the umbilical shoulders. The proportionate increase by growth of the ventro- dorsal diameters is also greater with relation to the transverse than in the stouter variety described below, and in all these respects it differs still more from Knem. syriacum. he shell, however, until 45 to 50 mm. in diameter is not distinguishable from the shell of that species. As stated by Fraas and Hamlin, the sutures in the worn casts are similar to syriacum, but in a large specimen of the same size as the type of this species (Pl. XVI, fig. 15) in the Museum of Comparative Zoology these are less worn than usual and full grown. These sutures (Pl. XVI, figs. 17, 18) show the large ventral lobes, which occupy nearly the entire breadth of the venter instead of only the central part, as in the stouter variety and in syriacum. The lateral saddles and lobes are very long and narrow and the bases of the saddles swollen, rounded, and phylliform, resembling those of Sphenodiscus. The apical ends of the saddles are also similarly shaped, broad, denticulated, and cutting deeply into the saddles. In the gerontic stage the lobes and saddles become shorter again, as in the younger stages, and more like those of syriacum. The most perfect cast (Pl. XVI, figs. 15, 16) is 70 mm. in diameter, without living chamber, the outer volution 38 mm., the umbilicus 10 mm., and same volution opposite 22 mm., the thickness of the last being 13 mm. between coste. The largest specimen is from Beirut, No. 10902G in the collection of Columbia University. This has no living chamber, and the actual diameter is 85 mm., estimated diameter about 90 mm. Diameter when living chamber was present could not have been Jess than 1380 mm. 150 PSEUDOCERATITES OF THE CRETACEOUS. Sutures are considerably worn, except in one place at diameter of 75 mm., the volution being 23 mm. ventro-dorsal diameter. These were similar to those of the typical specimens, except the first lateral saddles, which were narrower and distinctly bifid; the innermost inflections were not seen. The nodes were present on the umbilical shoulders, but apparently disappear on the last half of the outer volution, but this could not be proved on account of the state of this fossil. The venter remained concave to the end. The ventral tubercles became, however, much finer and more closely set than in the ephebic stage, and I should think more perfect specimens might show the correlative disappearance or obsolescence of the costations. I doubt if the coste are ever so broad in this species as in syriacum. The state of these fossil casts tends to confirm the opinion that they were not living members of the fauna with which they were found. Out of the eight casts in the Museum of Comparative Zoology only three were suitable for observation, and all of the three more or less imperfect, and there was not even the minutest piece of a shell on any of them. The same is also true of the large specimen from the collection of Columbia University. KKNEMICERAS COMPRESSUM var. SUBCOMPRESSUM Hyatt. Pl. XVI, figs. 11-14, 19. Amm. syriacus (pars) von Buch, Abhandl. K. Acad. Wiss. zu Berlin, 1848 (not figured). Amm. syriacus (pars) Conrad, Lynch’s Exp. Dead Sea and Jordan, 1852, pl. 14, fig. 74, two upper figures (not fig. 6). This variety has heretofore been confounded with nem. syriacum, from which it is, however, easily separated. The form even in extreme age is more compressed, the nodes on the umbilical shoulders are not so promi- nent, and the venter and transverse diameters do not broaden out in the later ephebic and gerontic substages, as in that species; the nodes also on the edges of the venter are longer and narrower than in that species. The sutures are very similar in these two forms. A specimen from Mukhtara, Syria, in the American Museum of Natural History, New York, reaches 97 mm. diameter without living cham- ber, and shows that the shell sometimes reaches a larger size than 115 mm. in diameter. KNEMICERATID. 151 A specimen in the Museum of Comparative Zoology is 50 mim. in diameter. This retained its flatter sides and proportionally broad venter to the end of the last volution. The living chamber is incomplete and somewhat less than half of a volution in length. A specimen from Abeih, Mount Lebanon, in the Museum of Comparative Zoology, 53 mm. in diam- eter, has a living chamber obviously very nearly complete and somewhat less than half a volution in length. This is therefore approximately the length of this part. One of the specimens in the Krantz collection in the Museum of Comparative Zoology shows thick shell on venter where it has been covered and protected by outer volution. Outside of this the cast is worn more or less, and there are absolutely no remnants of shell under the encrusting ostreans that occur on the exposed parts. The condition, in other words, proves that this and probably other fossils mentioned above were not living members of the Syrian fauna as heretofore described, but came from some earlier epoch and were already in the condition of fossil casts when the incrusting ostreans grew upon them. Locality: Gilead Mountains east of Jordan, Mount Lebanon, Syria. Age: Cenomanian. KNEMICERAS ATTENUATUM (Hyatt). Pl. XVI, figs. 13-15. Buchiceras attenuatum Hyatt, 1875, Proc. Boston Soe. Nat. Hist., Vol. XVII, p. 372. Glottoceras attenuatum Hyatt, ibid, note. The sutures agree quite closely with those of Knemiceras compressum, but the alternating tubercles on the edges of the venter and the form of this part are essentially Engonoceran. The original specimen is 65 mm. in diameter; it is a cast without any vestiges of the shell. The ventral lobe is deep and narrow and like that of Knemiceras The first lateral saddle is also Knemiceran in outline. It is unequally divided into three parts. The outer arm is trifid, but with such slight marginals that they are merely sinuosities. The central part is a minute saddle, and the inner has a trifid base. The second lateral is phylliform and so faintly bifid that I was not sure of the fact. All the remaining saddles are subphylliform, with broad bases and symmetrically bifid, except the seventh and eighth, the last on the line of involution. These are entire. The first to the sixth lobes are simple and denticulated; the seventh and eighth are entire. 152 PSEUDOCERATITES OF THE CRETACEOUS. This species was named erroneously Glottoceras in a note quoted above and accidentally left uncorrected in the proof. The great regularity of the outlines of the bifid saddles and the small dividing marginal lobes are probably characteristic, as well as the fineness and number of the tubercles of the outer lines and the presence of a third line beginning, apparently, on the latter part of the outer volution. Locality: Celendin, Peru. Age: Cenomanian? KNEMICERAS GABBI n. sp. Hyatt. Pl. XVIIL, figs. 1-3. Ammonites attenuatus Gabb, 1877, Jour. Acad. Nat. Sci. Philadelphia, 2d series, Vol. VILL. p. 264, pl. 36, fig. 1 @ and d. The originals of Gabb’s figures have not been found in the collections of the Academy of Sciences of Philadelphia and I could not obtain them for comparison, but the suture line figured by Gabb is distinct from that given on Pl. XVII of this work, and Gabb’s form is much stouter at the same age, has larger nodes and a broader venter. The old age with a rounded broad venter is probably not particularly distinctive, although it may perhaps be that this change never occurs to such excess in true attenuatum as it does in gabbi. Locality: Quebrada de Huari, Peru. Age: Cenomanian? KNEMICERAS UHLIGI (Choffat). Placenticeras uhligi Choffat, 1898, Faune Crét. du Portugal, Vol. I, 2d series, pp. 4 and 77, pl. 2, figs. 3-5; pl. 4, fig. 2; and pl. 22, figs. 4446. i This is a compressed species similar to Kn. compresswm, but differing in the sutures. The saddles are very broad and have flat bases with more denticulations. The lobes are more like those of compressum, but the inner ones are quite different. The marginal divisions are less complete than in compressum. Locality: Portugal. Age: Lower Bellasian (Cenomanian.) ; DESCRIPTIONS OF SPECIES. 153 ENGONOCERATID-. Shells apt to be involute. The venter is concave and is occupied for its entire breadth by a smooth zone. The sutures are variable in the different genera and approximate in some forms to those of Sphenodiscus. ‘There is a similar tendency in most of the species to have broad saddles with phylliform bases, which are either entire or bifid, while the lobes have narrow bases and are more or less expanded apicad and apt to have trifid terminations. The simplicity and shortness of the saddles and lobes is correlated with the tendency to produce a much larger number of inflections and great variability in the outlines in the same species and sometimes even on different sides of the same specimen. The ventral lobes are short, spreading apically, and have usually pointed short and entire siphonal saddles. PROTENGONOCERAS Hyatt. The ephebic form is compressed and involute, as in Engonoceras and Metengonoceras of the same subfamily group, and it is also similar to the neanic stages of Hngonoceras, Sphenodiscus, and Placenticeras. The shell is smooth, except in the gerontic stage, where folds appear. The venter is moderately broad and decidedly concave, bordered by sharp, smooth ridges. These are exactly the external characters of the young during neanic stages of the species of the different genera mentioned. The sutures have the same ventral lobes as in Engonoceras and Metengonoceras, and similar lateral sutures, but the saddles are very broad and short and the lobes have fewer marginals. Type, Prot. gabbi (Bohm), Whitney collection, in Museum of Com- parative Zoology. The septa follow internally the curvatures of the sutures, concave along the mesal plane and convex only on the areas on each side of the zone of involution. PROTENGONOCERAS GABBI (Bohm). Pl. XVII, figs. 16-20. Ammonites pedernalis Gabb, 1869, Pal. California, Vol. LH, pl. 35, figs. 1, 1a. Engonoceras gabbi Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, p. 197. A east of one-half of a volution in Museum of Comparative Zoology from Professor Whitney shows ephebic stage. The whole diameter, partly 154 PSEUDOCERATITES OF THE CRETACEOUS. estimated, is 69.5 mm., the outer portion of this volution, partly estimated, is 42.5 mm., the umbilicus is 5 mm. and the opposite part of same volution is 22 mm. The shell is present on the venter but not on the line of involu- tion. Greatest transverse diameter of outer volution is 25 mm., the inner ‘part is 11 mm., both through the umbilical shoulders, shell on one side and not on the other side. Probably shell would have made the difference of 5-mm. in each case. This is a compressed shell, closely similar in aspect to Engonoceras uddeni and the ephebic smooth stage of Protengonoceras ? emarginatum, but the involution is greater; the costations in this stage are fainter, but can be plainly enough seen both on cast and on the shell in a cross light. They are less than in Gabb’s figure, but the form of venter and aspect of shell, including amount of involution, shows that we are dealing with Gabb’s species. There are also no tubercles on the umbilical shoulders. The first large fold is partly present on the broken edge of the outer volution in the small fragment figured, showing the beginning of the gerontic stage. The venter is decidedly concave with slight ridges on either side. This form of venter is found in the neanic stage and the whorls, although stouter, are similarly compressed when the whole diameter is only 13 mm. At diameter of +4 mm. this venter, although almost as broad as the trans- verse diameter, is already like that of the adult, but may be a little flatter. Other details could not be seen. It is obvious that the young acquire the concavity and sharp lateral ridges of the venter in an early neanic substage at a time when the volution becomes flattened on the lateral zones. The form is then obviously like some stouter and less involute forms of this genus not yet discovered. The sutures are very slightly flexed apicad; the saddles and lobes closely similar to those of Metengonoceras. The venter is slightly asymmetrical; the first pair of saddles on the right are divided by a very slight marginal lobe. . There are nine saddles and eight lobes on the right side, the seventh saddle alone being bifid. The marginal lobe dividing this saddle appears on the earliest suture of this volution. Lobes on the left side of a more advanced stage show that this simplicity is due to age. A larger specimen, same locality, in the gerontic stage, is 108.5 mm. in diameter and has the shell preserved. Outer part is 57.5 mm., umbilicus ENGONOCERATID 2. 155 7.5 mm., and opposite side same volution 46.5 mm., no shell present. The greatest transverse diameter of the volution is 30 mm., and of thesmaller part opposite is 22 mm. The shell is marked by bands of growth and fold-like obscure coste which appear in the gerontic stage. These terminate at the umbilical shoulders, and along the centran surface of the lateral aspect have very broad swellings and then subside into the flat general surface toward the periphery. The venter is slightly broader than in the ephebic stage above described and the volution stouter, owing to the development of lateral swellings and the slight decrease in the involution due to old age. The umbilical shoulders and the umbilical zones are abrupt instead of being rounded and sloping as in the adults. The living chamber is complete near the line of involution and is about one-half of a volution long internally and apparently about the same externally when restored. The concavity of the venter is maintained for one-half of the length of the living chamber. Beyond this it could not be followed, but there are some indications of the possible rounding of the venter in extreme age. The sutures are quite distinct from those of the ephebic stage in the specimen above described. There were eight saddles and seven lobes to the umbilical shoulders, remainder on the umbilical zones being concealed. The interesting fact, however, can be noted that in this gerontic stage new saddles and lobes were not added as the sides broadened. The increase of the sides was met by the broadening out of the saddles. The first laterals were very broad, the second and third had not changed much, but begin- ning with the fourth they became irregularly broader toward the umbilicus, and the seventh was 6 mm. in breadth, whereas the sixth lobe was only about 1 mm. long. The lobes remained about the same as in the adult stage. The form of the volutions, smooth concave venter, slightly costated sides, with large folds only in gerontic stage, and primitive sutures all show that this is a species like the similar stages in the development of tuberculated forms in Metengonoceras and also similar to the young of Placenticeras. It is, however, a deeply involute shell and is not therefore by any means the most primitive form of its own subseries. It indicates the existence of a distinct subseries having similar smooth concave venters and less involute or more discoidal shells, which in the gerontic stage become stouter with 156 PSEUDOCERATITES OF THE CRETACEOUS. gibbous sides and have also comparatively flattened or rounded and much wider venters. ; Having been loaned through the kindness of Dr. Pilsbry another speci- men of this species from the collection of the Academy of Sciences, Phila- delphia (Pl. XVII, fig. 20), I can state the following additional particulars: The diameter is about 82 mm., partly estimated. The living chamber is one-half of a volution in length on the periphery, but is much shorter on the line of involution, owing to the great apical trend of the aperture. This has a broad but very slight sinus on either side and apparently no lateral erests on the sides that could be separated from the rostrum. This last, however, was broken and could not be decisively determined. The specimen is in its gerontic stage and upon the inner parts of each side has four heavy folds which disappear near the venter. The bifidity of the internal saddles is variable, since in another specimen in the collection ot the Museum of Comparative Zoology the sixth saddles were bifid. Locality: Avivechi, Sonora, Mexico. Age: Fredericksburg group, Comanche series. | PROTENGONOCERAS PLANUM n. sp. Hyatt. Pl. XVIII, figs. 6-9. This species is described from a fragment which would be ordinarily insufficient for diagnostic work.. The greatest length of this piece is only 22.5 mm., the ventro-dorsal diameter of the volution 14 mm., the greatest diameter at umbilical shoulders 5.6 mm. Nevertheless, the cast is perfectly smooth, the sides flat, and the venter, which is only 1 mm. in width, is also smooth, concave, and bicarinate. These characteristics, especially the attenuated venter and smooth sides, distinguish it quite sufficiently from the preceding species to justify specific separation. There are ten saddles, ail narrow, the first symmetrically bifurcated, as in other forms of this genus and Hngonoceras. ‘They are entire and from second to eighth more or less club shaped, but the ninth is broader and bifid. The tenth and eleventh are entire, occupying the umbilical zone. The dorsal zone of impression has six saddles, counting the outermost one above mentioned (Pl. XVIII, fig. 9). There are ten narrow zygous external lobes (Pl. XVIII, fig. 8) on the right side. The first is club shaped and entire, the second to the fifth similar, but faintly trifid) The sixth to the tenth are shorter and decrease ENGONOCERATID &. Ne in length to the line of involution and are entire. On the opposite or left side there are ten saddles and eleven lobes. The tenth saddle is completed, and there is a small lobe on the line of involution. The first saddle is narrower and the eighth and ninth saddles broad, and both similar to the ninth on the right side in being bifid. On both sides the first five lobes are long, and the same change occurs in the shortness of the sixth and remaining lobes and saddles. The matrix is similar to that which occurs in the Colorado formation at Horton’s mill, Dallas County, Tex. Locality: Texas. Age: Stanton suggests Upper Cretaceous from the matrix. PROTENGONOCERAS ? EMARGINATUM (Cragin).“ Sphenodiscus emarginatus ? Cragin, 1893, Geol. Surv. Texas, Fourth Ann. Rept., p. 245. This species is described as having straight distinct ventral channel at the diameter of 90 mm. and also as having two rows of feeble tubercles, one on the umbilical shoulders and the other midway on the lateral aspect. The bilobed saddles mentioned by Cragin indicate a more complicated suture line than occurs in Protengonoceras as far as known, but the condition of the venter indicates that genus. Not having seen any specimens of the species, I can not say positively that it is a member of this genus. : Locality: 2 miles south of Pleasant Point, Tex. Age: Comanche series, Walnut beds. ENGONOCERAS Neumayr. Although the descriptions and figures of Engonoceras pierdenale led me to believe that this species had an acute venter, Bohm” has stated, after studying the fragmentary originals, that these had truncated concave venters, bordered by ventro-lateral ridges or elongated tubercles, and that the species upon which the genus Engonoceras was founded, Anum. pierdenalis v. Buch, closely resembles his Eng stolleyi. The two fragments figured by B6hm do not show conclusively that this is the fact, but it appears to be safest to follow him in the effort to give stability to von Buch’s name and Neumayr’s genus. Von Buch’s and Roemer’s descriptions lead to the belief that the aSee p. 177, where this species is referred to Hngonoceras.—T. W. S. bUeber Ammonites pedernalis v. Buch: Zeitschr. Deutsch. geol. Gesell., Vol. L, 1898, p. 183. 158 PSEUDOCERATITES OF THE CRETACEOUS. shell casts they described had acute venters, but this is probably an error. In studying this group of fossils such a mistake is easily made, owing to the simplicity of the sutures, the narrowness of the flattened venters, and smooth- ness and symmetrical aspect of the fossils, although considerably worn and altered by abrasion. _ The presence of three distinct lines of nodes, the flatness and nodose edges of the venter throughout the earlier and ephebic stages, the broad and often zigzag outline of the venter in the gerontic stage, caused by the extra development of the outer line of alternating nodes, enable one to separate the species of this genus readily from those of Metengonoceras, notwithstanding the close similarity of the sutures. The young during the neanic stage are compressed, involute, and smooth, with concave venter and form like Pro- tengonoceras. Von Buch and Neumayr both describe the principal saddles of Engonoceras pierdenale as bifid, and this occurs in the species here sup- posed to represent Engonoceras, but does not occur, so far as known, in Metengonoceras. All specimens so far seen have been casts, either entirely naked or with only the nacreous layer partly preserved. The attention of collectors is called to the fact that some of the species bear no convincing marks of having been autochthonous members of the faunas in which they are habitually found. This genus differs from Neolobites onky in having denticulated lobes, if the figures of the sutures heretofore given correctly represent their outlines. _ ENGONOCERAS BELVIDERENSE (Cragin). Pl. XVII, figs. 4, 5. Ammonites belviderensis Cragin, 1894, 1895, Am. Geol., Vol. XIV, pl. 1, figs. 3-5; Vol. XVI, p. 369. i Buchiceras (Sphenodiscus) belwiderense Cragin, 1900, Colorado Coll. Studies, Vol. VIL, p. 27. Through the kindness of Professor Cragin I have seen some specimens of this species, and one of these has been given in the figure. This alone was not much crushed, but the sutures could not be made out. The aspect is similar to that of Eng. uddeni, but the sides and venter are flatter and smoother. There are similar nodes on the umbilical shoulders and those on the edges are alternate; there are nascent folds on the outer part of the sides. It reaches a larger size than other forms before it begins to acquire ENGONOCERATID®. 159 the usual gerontic characters—that is, before the venter becomes convex and more or less zigzag in outline.. The type of Cragin’s species is the small specimen referred to above. This has sutures with numerous small saddles closely set on the suture line, and, so far as could be seen, one of Cragin’s fossils of the same lot with that figured had similar sutures. Cragin describes this species as having a row of tubercles that may be developed on the inner ends of the low folds or costee occupying the outer half of the sides. There are some very obscure signs of the existence of such markings in these fossils also. These are doubtful even to the touch and are not visible to the eye. This may be owing to the condition of the fossils. Locality: Belvidere, Kans. Age: Champion bed and Kiowa shales, probably near base of Washita Comanche series, Lower Cretaceous. ENGONOCERAS UDDENI (Cragin). Pl. XIX, figs. 1-6. Sphenodiscus belviderensis var. uddeni Cragin, 1900, Colorado Coll. Studies, Vol. VIII, p. 30, pl. 1, figs. 3, 4. A fragmentary cast in iron pyrite, No. 23147 U.S. National Museum, Pl. XIX, fig. 4,5, shows a few of the last sutures and a portion of the living chamber. The diameter, partly estimated, is about 82 mm., the outer volution is 44 mm., the umbilicus 8 mm., the same volution opposite from line of involution to venter 30 mm., no shell being present. The form is compressed and highly involute, but slightly stouter than in the more compressed emarginatum. There is only one line of nodes, those on the umbilical shoulders. The costz are fine, and like elevated bands of growth gathered to a focus at these nodes. They are sigmoidal with single fine lines between the nodes, externally more pronounced folds appearing in the later gerontic substage, but no nodes are present on this part in this specimen. The venter is flattened until near the last part of the living chamber, which is distorted through compression. The part of the living chamber preserved indicates that it was not less than half a volution on the umbilical side. The ten lobes and eleven saddles on both sides are very similar in outline to those of emarginatum. The seventh and eighth lobes on both sides are bifid. 160 PSEUDOCERATITES OF THE CRETACEOUS. -The ventral and also the first lateral saddle are asymmetrical. These have the usual form but are rather narrow. The internal parts of the sutures are deflected orad toward the umbilical shoulders so that they rise materially, giving them a pecular aspect in this specimen. The lobes are similar to those of emarginatum, but are narrower and shorter and the saddles broader and shorter in proportion. The second to the sixth saddles are entire, the seventh to the ninth bifid, and the tenth saddle is on the line of involution. The sutures are the same on both sides of this specimen. The lobes are irregularly bifid. There is a fragment of a larger size consisting of one-fourth of a volution with stouter proportions, labeled ‘‘ Locality 1490 U. S. Geological Survey, north of Pottsboro, Tex., Upper Comanche (Grayson),” that may belong to the same species, but the sutures and aspect are distinct enough to belong to a different species.“ The inner line of large nodes and the median lateral are present, but no outer line, and there are similar distinct costations. The venter has a similar outline also, but the specimen being larger and older, the venter is more rounded. The sutures are similar, except that the inner arm of the first lateral saddle is much narrower and entire, the outer arm is distinctly bifid, making the whole outline approximately. trifid, the remaining saddles are longer and distinctly phylliform as in Sphenodiscus, and the lobes are correspondingly broader apically as in that genus. These effects may perhaps be due to the greater age of the specimen. There is apparently the same number of lobes and saddles. There are nine saddles visible on the broken end, right side, and there may be one more, making ten saddles and nine lobes. A fragment obtained from Dr. F. A. Udden, locality northeast of Little River station, Rice County, Kans., is the original specimen used by Cragin and is figured below on Pl. XIX. It is in fine state of preservation, being fossilized with iron pyrite. The breadth of the side is 53 mm., the greatest transverse diameter is at about one-third of the breadth from the line of involution and is 20.5 mm. Theventer is very narrow, about 3 mm. in breadth; it has no obvious nodes, but, as in the type, faint undulations may be felt with the finger on the ventro-lateral angles. The sutures are quite different, but have the same general character. The first lateral saddles are quite distinct on the two sides, owing to the asymmetry of the ventral lobe. 4 Figured as Engonoceras retardum n. sp. Hyatt, Pl. XV, figs. 15-17. ENGONOCERATID 2. 161 The sixth saddle on the left side is bifid; the seventh is broad and symmetrically and deeply bifid, looking like two entire saddles; the eighth has a large, slightly bifid, outer and a tongue-shaped inner arm; the tenth is bifid. The ninth and tenth can be reckoned in several different ways on account of the peculiar formation of the lobes, either as above, or the inner arm of the ninth be called the tenth and what is here named the tenth can be classed as the eleventh, or, on account of shortness of the lobes, the whole may be considered as a single broad saddle with three arms, the outer and inner arms bifid and central arm narrow and entire. The eleventh saddle is trifid and broad, the twelfth and thirteenth entire, and the last is on the line of involution. On the right side the first lateral saddles, on account of the asymmetry of the ventral lobe, are narrower and the second is much reduced. The second to the seventh are entire, the eighth and ninth are symmetrically bifid, the tenth to the thirteenth are entire. The twelfth and thirteenth saddles alone correspond or are symmetrical, bilateral on both sides of the body. The lobes have a ten- dency to become irregular at their terminations and are long and narrow on both sides and more alike than the saddles. There is also a large fragment of an example of this species in its gerontic stage, or of an undescribed species, associated on same mount with EH. subjectum (No. 10755 Collection Boston Society Natural History). The diameter from line of involution toward venter as far as fragment goes is 68 mm. There are only a few millimeters wanting externally, since part of the first saddle is present. There are apparently nine saddles only on the side, all entire except the seventh, eighth, and ninth, which are bifid. The first to fourth lobes are long and narrow and the saddles stout but phylliform. These sutures belong obviously to a very aged shell, since out of nine sutures visible the eighth is the first that does not slightly overlap and the last four overlap progressively more and more. The absence or very slight development of the outer lines of nodes and the absence of distinct ridges on the ventro-lateral edges of the venter distinguish this species from LH. subjectum. The sutures of these two run closely together, although the saddles and lobes of this form are somewhat stouter and broader at the same age than in EL. subjectwm. Locality: McPherson County, Kans. Age: Comanche series, Kiowa shales. MON XLIV—03 st 162 PSEUDOCERATITES OF THE CRETACEOUS. ENGONOCERAS SERPENTINUM (Cragin). Pl. XIX, figs. 7-14; Pl. XX, figs. 1-5. Sphenodiscus belviderensis var. serpentinus Cragin, 1900, Colorado Coll. Studies, Vol. VII, p. 31, pl. 2, figs. 4-6. Three casts of this species (Loc. No. 1489) are well preserved in a matrix of hematite. The diameter of one (1489 b) is 58 mm., the volution is 29 mm., the umbilicus 7 mm.; the same volution opposite, measured from lines of involution to venter, 22 mm., no shell being present. The involution conveys the larger part of each outer whorl, but the internal volutions are plainly visible in the umbilicus and the involution is obviously much less in the younger stages than in adults. The volutions are much compressed. The venter is, however, flattened and slightly con- cave in the ephebic stage, and in the gerontic stage it becomes asymmetrical and sinuous through the development of the large tubercular terminations of the alternating costee. In the ephebic stage the costee are sigmoidal and only slightly developed; in the gerontic stage these become broad on the outer parts with an external and internal line of nodes, and become obscure internally or umbilicad of the second row of nodes, but they are obviously confluent to the internal or third line of smaller nodes on the umbilical shoulders. These nodes, like the costae, come in on the casts at a late ephebic substage, the side of the younger whorls being smooth. The tubercles of the outer line in the one specimen (1489 b) are sharper and the coste at the points convergent, whereas in the second specimen from the same locality the latter broaden out and the tubercular terminations are more elongated This, however, resembles those of the other specimen in the ephebic and anagerontic substage, the marked elongation coming in with the metagerontic substage. A similar disposition to broadening out of costz is also observed in the larger specimens in extreme age, but is not so marked and the venter also remains narrower. The living chamber is not complete, but it must have been about one-half of a volution in length on the line of involution. Other specimens show the same, but none give the outer margins. The imner lines of tubercles remain close to the umbilical shoulder, receding outwardly very slightly in extreme age. ENGONOCERATID &. 163 The variation between different specimens in external aspect of the casts is not great except in the gerontic stage owing to the greater or less development of the nodose costations, but the variations in the sutures are such that no two specimens are alike. The fourth suture on right side of figured specimen has eleven lobes and ten saddles, and is only slightly curved apicad. The arms of the ventral lobe are seen cutting deep into the lateral aspect. The inner branch of the first lateral saddle is broad, entire, and club-shaped, as are all other saddles, except the ninth and tenth, which are bifid. The depth and size of the lobe that divides what is here assumed to be the first lateral is so like other lobes that it is not always easy to determine whether it is a marginal or really the first lateral lobe. The lobes are all clubbed; that is, narrow orad and swelling-out apicad, and from first to seventh show very faint digitations or indications of from three to four very minute incipient marginal lobes, the fifth showing the equal and the remainder the unequal numbers of these. Specimen 1489a has short lobes and corresponding saddles like the above, but narrow outer branches to the first lateral saddles and arms of ventral lobe hardly apparent on the lateral aspect. There are eleven lobes and ten saddles easily distinguishable, i. e., not overlapping and similar to those of the first specimen, but saddles narrower outwardly and broader imwardly, and, what is more remarkable, the seventh, ninth, and tenth are bifid, the eighth, which is bifid in the first specimen, being entire in this. Specimen 1489¢ has such distinct sutures that one hesitates to place it in the same species with those marked 1489a and 1489b. The sutures are more deeply curved apicad, the outer five saddles and lobes longer and narrower, and the inner ones broader and flatter. There are, however, eleven lobes and ten saddles visible, as in the others, and the age is about the same. The sutures are, however, closely approximated, so that the lobes slightly overlap even in the ephebic stage and form columns except along the lines of the first to the second. The ninth saddle alone is bifid, all others being entire. The discoidal aspect of the young in the umbilicus can be plainly seen in this specimen. The sutures on the left side have the same general character, but differ in details from those of the right side. The outer saddles are alike, but the inner ones are narrow and more numerous. 164 PSEUDOCERATITES OF THE CRETACEOUS. The fragments from Denison consist of an almost entire gerontic living chamber and one somewhat more imperfect one of the same age, a smaller fragment of part of ephebic living chamber and last suture. This last shows that in the ephebic stage the venter is smooth, narrow, concave, and has no tubercles, but is bordered by two smooth ridges. There are nine lobes and nine saddles, the seventh and eighth saddles being bifid. The line of involution is occupied by a minute lobe, as it is also in other specimens. There are five dorsal lobes between this and the antisiphonal lobe on each side. he first dorsal saddle next the antisiphonal is entire, the second and fifth are bifid, the rest are entire. The third dorsal lobe was bifid, the remainder on both sides of this were entire and narrower. The antisiphonal lobe was narrow and bifid. The sutures of an early ephebic or late neanic substage in one of these showed that the notation of the saddles in this group is correct, and that the first lateral has, as stated, two unequal arms, the inner being really an adventitious saddle derived from the imner side of the first lateral. The outer saddles and lobes are similar in outline to those of some specimens from northeast of Gainesville, but the inner saddles and lobes are shorter and broader.. : A specimen from Denison, kindly lent me by Prof. F. W. Cragin [is also figured and is probably one of the types of his variety serpentinus now raised to specific rank]. This species is distinguishable from others by the extremely late stage to which the protengonoceran venter—i. e., the concave venter bordered by two ridges—is retained. Practically it lasts throughout the ephebic stage, and the engonoceran stage is passed through with great rapidity. In this the venter is flat and bordered by weli-defined elongated tubercles, and consequently there is a quick appearance of the senile stage with elevated convex venter between large elongated nodes. It should be noticed that one of the varieties imitates the sutures of EH. subjectum in the shape of the saddles and lobes, but these remain characteristically simple in outline (Pl. XIX, fig. 11). Some varieties have bifid saddles and some do not have them. The dividing marginals of the saddles enlarge by growth when they occur, until they often form lobes practically inseparable from others. Locality: Four and one-half miles northeast of Gainesville and Denison, Tex. Age: Upper part of Comanche series, Paw Paw beds, Washita group. ENGONOCERATID &. 165 ENGONOCERAS PIERDENALE (von Buch). Pl. XX, figs. 6-13. Ammonites pierdenalis yon Buch, Abhandl. K. Akad. Wiss. zu Berlin, 1848, pl. 6, fies. 8-10. Ammonites pedernalis Roemer, 1852, Kreideb. vy. Texas, Pl. I, fig. 3. Engonoceras pedernalis Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, p. 183. I have placed this here with a query, because I find it impracticable to identify the young figured by von Buch with any form known to me. The ventral lobe and saddle and the other parts of the suture might belong to the young of a species a grade more complicated than any here described. There is a row of elongated nodes close to the venter in von Buch’s figure, but the presence of such ornaments is denied in the text, and the nodes are said to be on one side and due to the exposure of the joints of the siphuncle. Roemer states that he had the originals in hand when making his deserip- tion, and that the species was much larger than that described by him. Neumayr mentioned this species as the type of his genus Engonoceras* and repeats the name ‘‘pierdenalis” instead of ‘“pedernalis,” the name given by Roemer, and also repeats von Buch’s figure of the suture on PI. 7 ot Uber Ceratiten. Von Buch and Neumayr also both describe the principal saddles as bifid, a condition that does not exist in any specimen of the genus that I have seen. Locality: Texas. Age: Fredericksburg group of Comanche series. EXNGONOCERAS PIERDENALE variety COMMUNE Hyatt. JBL, ROG we, Al, A fragment in U. 8. National Museum, No. 8301b, from Bell County, Tex., is slightly crushed in the umbilical region, but has sutures and mark- ings well preserved. At larger end the volution is 33 by 14 mm., at smaller end 24 by 11 mm. The venter is flattened and narrow, bordered by small elongated tubercles rather numerous and closely set as in the adults of this species. There is an inner row of tubercles, hardly perceptible median row, and equally faint fold-like costations on the outer part of the volution, which can be felt better than seen on this cast. «Amm. d. Hilsbild. Norddeutschlands, Paleontogr., Vol. XX VII, 1880-81, pp. 138, 141. 166: PSEUDOCERATITES OF THE CRETACEOUS. The ventral lobe is slightly asymmetrical to the left, giving rise to cousiderable differences in the first lateral saddles on either side. The first lateral on the right is bifid, the outer arm very broad and bifid, the inner subdivided asymmetrically by a very minute marginal lobe. Beyond this the inner arm is entire and quite large and phylliform. There are ten saddles and nine lobes on this side All the former are entire except the innermost, which is slightly bifid. The lobes vary from trifid to six-pointed. On the left side the first lateral saddles have the usual bifid form without further subdivisions. All the saddles appear to have entire phylliform out- lines, but this may be due to the worn sutures. The first to fourth lobes are slightly digitated, the fifth is faintly trifid, and beyond they are too much worn to show the minute serrations. On the left side the first lateral saddles have the usual bifid form, the outer arm broad, pointed externally, and with only a slight indentation on the margin. The second to seventh lateral saddles are entire and phylli- form; the eighth is broad and deeply bifid, but is apparently only one saddle; the ninth and tenth are entire. The first to fourth lobes are faintly denticulated, the fifth and sixth narrow and trifid. The seventh is totally unlike any other lobe. It seems to be filed by a pointed saddle, the end bifid in one case. There is also another specimen from the same locality, a cast with a part of a living chamber preserved. ‘This is about one-half of a volution and in the gerontic stage, the last five sutures overlapping. The preceding sixth or eighth, being in the ephebic stage, do not overlap. The lobes and saddles are like those of the fragment just described, the sixth to the eighth saddle on the right side being bifid and the ninth entire. The saddles in old age, however, are flatter and the lobes become shorter. The ornaments are the same as in other specimens, but the venter becomes broader in proportion to age; tubercles persistent. The living chamber is obviously nearly complete and must have been at least one-half of a volution in length. Three small fragments from locality No. 1554, Seven Knobs, near Glenrose, Tex., have tubercles larger and more prominent, and although the sutures vary they are near enough to belong to the same species. The largest specimen over one-half of a volution is 52 mm. in diameter. Probably, allowing for compression, this diameter is only 45 mm. The ENGONOCERATID 2. 167 living chamber is about one-half of a volution and is nearly complete. The venter broadens out, and this specimen seems to be outgrown, judging from the approximation of the last three septa. The sutures are similar to those of the preceding, but the seventh saddles are bifid. Specimen from locality 1545, Chalk Mountain, near Glenrose, diameter of volution 50 mm., partly estimated, has seventh saddle on the right side bifid; all others external to this entire and phylliform, except, of course, first lateral. This cast shows plainly that what is here counted as the second lateral is an adventitious saddle derived from division of the first lateral saddles, and the first lateral lobe is also an adventitious inflection arising from a primitive marginal of the first lateral saddle. A fragment from the Goodland limestone, Choctaw Nation, about 100 miles east of Preston, Tex., is considerably worn, but apparently of this species. The volution is 33 mm. from line of involution to venter and:is in gerontic stage, the last six sutures overlapping. The venter is also rapidly broadening, the gerontic tubercles and costz are larger than usual, and the venter is more asymmetrical or zigzag in outline. There are nine saddles visible, and the seventh and eighth are bifid; the outlines of others are entire. The lobes, owing probably to attrition, are all entire. A specimen in the United States National Museum, No. 22643, from locality No. 973, near Cerrogordo, Ark., has a combimation of characters which appears to unite serpentinum with pierdenale. he sutures have the broad, short saddles with flat bases, like those of serpentinum from near Gainesville, but the size of specimen, nodes, and aspect are similar to the typical fossils of prerdenale. The surface is worn down somewhat in this east, and probably these resemblances may be due to this cause. This cast is 91 mm. in whole diameter; transverse diameter estimated at 20 mm. A cast in the Museum of Comparative Zoology from Towash, Hill County, Tex., is 56 mm. in diameter; the outer volution is 27 mm., the umbilicus 8 mm., and the opposite part of same volution from line of involution to venter 21 mm. This is an outgrown specimen, the last six sutures overlapping those preceding, while in ephebic stage they are separated by a distinct interval. There are the usual lines of tubercles, and the cost on the outer part of the volution become very decided, as in other aged specimens. The venter is at first narrow, but this becomes much broader at the same time that costz 168 PSEUDOCERATITES OF THE CRETACEOUS. increase in size in last part of the outer volution. The venter runs from 2 to 7 mm. in width on this one volution. The living chamber is complete internally and is somewhat less than one-half of a volution in length. The sutures resemble those of specimens described above except that there are only seven saddles, the fifth and sixth very broad and bifid, the seventh entire. The first to third lobes are very slightly digitated; the rest are entire. Bohin’s studies of the originals of the descriptions of this species have been referred to in the generic description. Whatever doubts of Bohm’s con- clusions may remain in the mind, it is surely safer to follow such an investi- gator, who has worked over the original materials, than to indulge in speculations with regard to the exact meaning of von Buch’s and Roemer’s descriptions and figures, about which the most opposite opmions might be reasonably entertained. ENGONOCERAS SUBJECTUM n. sp. Hyatt. Pl. XXI, figs. 2-6; Pl. XXII, figs. 1-5. A good cast of this form (No. 431 in Museum of Comparative Zoology) is 101 mm. in diameter, the inner oldest part of the outer volution being partially destroyed, so that this could not be measured. The living chamber was probably, when perfect, not less than one-half of a volution in length. The whole diameter was about 102 mm.; the transverse diameter was decreased so by compression that the measurement near base of living chamber could not be relied on, but this was 18 mm., the ventro-dorsal breadth of side being at the same place 43 mm. The living chamber having been excavated, it was possible to measure the interior volution in the same line with the largest diameter given above. This was found to be 73 mm., the largest volution being 40 mm., the umbilicus 7 mm., the opposite part of same volution 26 mm. No shell was present on this cast. The involution covers up the entire side of inner volution at diameter of 86 mm. This is found in several specimens, but does not appear to be invariable. There are large nodes along the umbilical shoulders, very obscure nodose folds along the central surfaces of lateral zones, and prominent elongated alternating nodes along either border of the venter. These last are finer in the ephebic stage than in the gerontic substages At diameter approaching 100 mm. the venter loses the flattened aspect ot ENGONOCERATID®. 169 ’ the ephebic stage, becomes broader and slightly rounded, but still retains the tubercles and asymmetrical aspect due to their prominence and alter- nation. The gerontic living chamber is about one-half of a volution in length on the ventral side, the dorsal side being absent. The earliest suture in type No. 431 at diameter of 26 mm. from line of involution to venter has eight saddles and seven lobes to the umbilical shoulders. Beyond this they were not visible. The saddles are narrow and phylliform or club shaped; the lobes also are clubbed and have primi- tive denticulations. First lateral saddle is trifid and inner marginal lobe is digitated, the second to fourth entire, fifth to eighth bifid. The ventral lobe is longer than usual in this genus, but has the usual form, divided by entire broad siphonal saddle. The first, second, and third laterals have about five denticulations unequally divided, and the fourth is trifid. Later in the gerontic stage the second to fourth saddles become either bifid or have more digitations, and the digitations of the lobes increase to seven; the phylliform aspect also increases. When the volution is about 37 mm. in diameter from line of involution to venter, there are apparently about the same number of saddles and lobes, Pl. XXI, fig. 5. The lobes have more denticulations and the third saddles are also faintly bifid. In another specimen, Pl. XXI, fig. 6, same locality at about the same age, all the saddles and lobes are shorter and broader in proportion, but decidedly phylliform, the lobes are more denticu- lated, the first lateral saddles deeply trifid, the second to fifth saddles entire, the sixth to the eighth (the last one visible) distinctly bifid. A cast (No. 10755, Boston Society of Natural History) from Bell County, Tex., is 75 mm. in whole diameter. The entire volution is 39 mm. from venter to line of involution; the umbilicus is 10 mm.; the diameter oppo- site from line of involution to venter is 27 mm. This is in the gerontic stage, the last five sutures overlapping. There are ten saddles and nine lobes on the left side. The second to the sixth are entire, the seventh to the ninth are bifid, and the tenth is entire. The saddles and lobes have the elongated phylliform character of this species. Locality: Gabriel, Williamson County, Tex. Age: Comanche series, Washita? The remarkable and highly instructive specimen described below is a cast with an approximate diameter of 55 mm. It was received from Dr. 170 PSEUDOCERATITES OF THE CRETACEOUS. D. S. Martin and came from Grayson, Tex. The sutures on the right side possess a decidedly unique aspect, having a first lateral saddle entirely different from that of any specimen of this genus | have yet studied or seen figured. The whole aspect of these sutures indicates a new species, whereas the sutures on the other side, although considerably abraded, are perfect enough in places to show the ordinary form of first lateral saudle commonly found in Metengonoceras. The sutures of the right side are more like those of EF. subjectum than those of E. pierdenale, but they are quite distinct from both in the aspects of the saddles. On the right side there are nine saddles and eight lobes. The first lateral saddle is broad and distinetly trifid. The inner arm is broad and has the usual shape of other species, being pointed externally and running well on to the venter. The central arm is a narrow, small marginal saddle between two small entire marginal lobes; the mner arm is narrower than the outer arm and phylliform. The second to the fourth saddle are entire and phylliform, the fifth and remaining saddles have flatter bases. The fifth is still entire and the remaining saddles also, except the sixth, which is bread and bifid. his bifid character can be detected only on the first part of the outer volution where the dividing lobes are not abraded, but even this is open to some doubt. The ventral lobe has the usual outline and is symmetrical in position; nevertheless the first lateral saddles on the left side are quite distinct from those on the right side. They have the usual bifid character of specimens of other species, and there is nothing unusual in the outlines of the sutures on this side. The seventh and eighth saddles are bifid, and the sixth is entire. The ninth saddle is broader than on the right side. The condition of the sutures on this side did not admit of more minute observations. The first to the fourth lobes on the right side were of the usual form, but rather coarsely serrated and similar to those of specimens from Bell County, Tex., described above (collection of the Boston Society of Natural History, No. 10755). It agreed also with the last im the prominence of the middle line of tubercles. Locality: Grayson, Tex. Similar sutures occur in a cast of this species kindly loaned me by Prof. F. W. Cragin, and in this the eighth saddles are on the umbilical shoulders and the broad ninth reaches to the line of involution; the second to the sixth saddles are entire; the seventh to the ninth are bifid. Locality: Tarrant County, Tex. ENGONOCERATID. eal The venter in this species remains concave and has a sharp ridge on either side at the ventro-lateral angles, broken into waves by equally acute but elongated nodes on the casts. Shells were not present. In old age these nodes: persist, but the ridges disappear and the venter becomes flat- tened, and finally convex. A cast from Denison, Tex, Duck Creek beds, United States Geolog- ical Survey, has very different sutures and is also somewhat different in general aspect. The living chamber is complete in the inner borders and is considerably less than one-fourth of a volution in length. It is in the gerontic stage; the inner tubercles are large, and the outer ones, terminating short, fold-like costee, are also very large. The venter is completely rounded and much zigzagged in correlation with the large tuberculose alternating folds and nodes of the coste. The whole diameter is 92 mm.; the outer volution, which is somewhat reduced by gerontic contraction, is 42 mm.; the umbilicus is 14 mm., this being enlarged in proportion to reduction of gerontic part of volution, and opposite from line of involution to venter is 36 mm. The saddles are quite distinct from those of specimens described above, but have the same distinctly phylliform aspect; the lobes are more alike and with similar serrations. There are nine saddles on the right side. The first lateral has the same deeply bifid form as in specimens of this species. The second to seventh have rounded leaf-like bases; the eighth is still phylliform, but broadens out and is bifid; the ninth is entire. The first lateral lobe is evidently very slightly divided, but the second to the fifth are more richly denticulated than the sixth and seventh and are faintly trifid (?); the eighth is perhaps entire, but not plainly seen. The living chamber is shorter in this specimen than in any other example of this species and the nodes are more like those of ser- pentinum, while the sutures agree better with those of subjectum. The principal distinction between this species and its allies of the same genus lies in the more elongated phylliform saddles and lobes. ENGONOCERAS GIBBosUM n. sp. Hyatt. Pl. XX, figs. 6-10; Pl. XXII, figs. 1-6. The best example of this species is an entire cast in my collection from Cook County, Tex. This has the median line of nodes along the central line of the lateral surface, the outer distinct and short and no perceptible 172 PSEUDOCERATITES OF THE CRETACEOUS. costze between these. This cast, the type of the species, shows no gerontic characters at the diameter of 93.5 mm. The greatest transverse diameter is at the umbilical shoulders and is 25 mm., the breadth of the side at the same point being 50 mm. The sutures are quite different from those speci- mens described below, but there is the same general character: the second lateral saddle and the fifth are bifid; the sixth is unequally trifid; the seventh is a compound saddle with two bifid arms; the eighth to the tenth are entire or flat. The more gibbous sides, the prolonged stage during which the nodes persist and are sharply defined, and the large number of bifid saddles characterize this species. The sutures are the most complex, with exception of Eng. roemeri, of any that have been so far descibed in the genus. The largest fragment in the National Museum is about three-eighths of a volution. Widest diameter is 91 mm.; the distance from line of invo- lution to venter is 50 mm. at the larger end and 38 mm. at the smaller end; and the transverse diameters are 20 mm. and 16 mm., respectively. This specimen was probably entirely uncompressed. The venter is narrow and flat and the sides are slightly gibbous and highly convergent outside of the middle row of obscure nodes. Between these and the umbilical shoulders, however, a flattened zone is developed, which may even slightly slope inward The usual row of nodes is present on the umbilical shoulders, and also the rows of alternating tubercles on each side of the venter. The latter are sharp and well formed, elongated, and sufficiently numerous to give a decidedly zigzag aspect to the narrow venter. The venter is flat in the early part of the neanic stage and much broader in proportion to the volution than in later stages, as it is in most species of this genus. The volution has more flattened sides at this age, and the involution begins to cover up the volutions to the umbilical shoulders even at this early stage. The sutures are well separated, as in other shells of this genus, and are very remarkable. There are on the right side ten lateral lobes and eleven saddles at the larger end of this fragment and the same number at the smaller end. These are more difficult to count and quite different on the left side. The ventral lobe is symmetrical and of the typical form. On the right side the first lateral saddle is bifid, the outer arm short, broad, and spreading, the inner also broader than in most other forms; the outer is subdivided by a minute marginal or slightly and unequally ENGONOCERATID &. Le) bifid; the inner arm is slightly trifid in nearly all the sutures, and this becomes more apparent in the older sutures. The lateral saddles are broadly phylliform. The second laterals are obscurely and equally bifid in all the sutures; the third shows a faint tendency to become bifid only im the older sutures; the fourth seems to have a similar tendency, but this does not become demonstrable, and it must be described as narrower at the base and entire. The fifth is bifid in the younger sutures observed, and becomes more distinctly bifid with age; the sixth is narrower and entire; the seventh is equally bifid; the eighth is also equally bifid, but the inner arm is unequally subdivided by a minute-marginal; the ninth is also equally bifid, and each arm is also bifid with a minute marginal lobe; in some sutures both are unequally divided and in others the outer is symmetrical, the inner asymmetrical; the tenth is small and entire, and the eleventh is very broad and is subdivided by a minute marginal lobe introduced on this volution, and the outer arm shows a tendency to broaden and become bifid in the older parts of the same. The saddles are phylliform but rather short and stumpy from second to sixth, then they become very broad and less phylli- form; the lobes have the usual narrow bases between the expanded bases of the saddles and spread out apicad between the phylliform saddles. These are all apparently unequally subdivided, and the digitations and serrations are somewhat more numerous in the second to the fifth laterals than in most other species. The first and sixth are simply trifid, the seventh and eighth bifid, the ninth and tenth entire. On the left side the first lateral saddles have a narrower outer arm, divided by a deeper marginal lobe, and the inner arm is not so broad and shows only a faint tendency to become bifid. The second lateral is more distinctly but unequally bifid; the third shows a faint tendency to a trifid undulation; the fourth is entire; the fifth is faintly bifid; the sixth is dis- tinctly but asymmetrically bifid; the seventh is equally and deeply bifid; the eighth is very broad and also deeply bifid, the outer arm has the margin faintly undulated into four nearly equal marginal serrations, the immer arm is asymmetrically bifid; the ninth is also unsymmetrically divided, the outer part or arm is very broad, rather rounded basally and undulated into three minute serrations on the margin, the inner arm is a minute saddle; the tenth saddle is like that of the right side, but faintly bifid im the first sutures seen; the eleventh saddle is narrower than on the right side and 174 PSEUDOCERATITES OF THE CRETACEOUS. entire. The lobes are all shorter, with broader ends apically and with less complex digitations than on the right side. One small specimen, a cast from locality 1492, 15 miles west of Denison, Tex., has a diameter of 46 mm., outer part of volution, 23 mm.; ry transverse diameter, 11 mm.; umbilicus, 7 mm.; and opposite diameter from line.of involution to venter, 16 mm.; transverse diameter, 7.5 mm. This has the same shape of venter and general aspect. The nodes of the inner line are present as elongated costz, which are most prominent at the umbilical shoulders and much inclined orad. Very obscure nodes could be felt over the more perfect surface of the cast along the centran lateral area. The cast was too imperfect along the venter to observe nodes, but at the beginning of this volution on a small bit of the shell of the venter exposed by excavation there were smooth ridges at the ventro-lateral angles, and the venter was concave. The sutures in this are crowded together unusually close for shells of this genus, the inner lobes and saddles overlapping slightly, beginning with the third lobes and fourth saddles. It is probably a dwarfed form of this species, since in the earlier part of same volution the sutures are well sepa- rated, as in other forms. The ventral lobes are obliterated, but sufficient of the first lateral saddles remain to show that they were unequally bifid and that the outer arm was also bifid, the inner arm entire and quite large. The second to fourth saddles on the left side were broad and entire, the fifth to seventh symmetrically and deeply bifid, the eighth very broad and unequally bifid, the outer arm faintly bifid, the ninth alone entire. There is considerable variation on the right side, the sixth saddle is not deeply bifid, the seventh is unequally bifid, the eighth is like that of the left side, but the bifidity of the margin of the outer arm is more pronounced. ‘The ventral lobe is symmetrical, but so much worn down that no observations were practicable except at two of the sutures, when it seemed to have the usual generic form. The living chamber was not present in either of the above-described specimens. A small cast from Bell County, Tex., No. 8301a, about a fourth of a volution, is 23 mm. in diameter from line of involution to venter, transverse diameter 14 mm., two lines of tubercles and median line of elevations well defined, venter distinctly concave. The sutures appear to have more ENGONOCERATID 2. 175 resemblances to those of the older stages of this species than to any others. The ventral lobe is narrow and slightly asymmetrical to the left, but the first lateral saddles on both sides are alike. They are both bifid, the outer arm is entire but is blunter than usual on the venter. The first to sixth saddles are otherwise like those of the specimen described above; the sev- enth to ninth saddles, seen only on the left side, are symmetrically bifid, the tenth is entire. This bifidity of the internal saddles agrees with those of uddent, but the aspect of the volution and the general form of the saddles and lobes agree better with those of this species. Locality: Cook County, Tex., 15 miles southwest of Gainesville and 15 miles west of Denison. Age: Fredericksburg division of Comanche series. EXNGONOCERAS STOLLEYI Bohm. P). XXII, figs. 7-9; Pl. XXIV, figs. 1-5. Engonoceras stolleyi Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, pl. 5. This species has the flattened venter, becoming alternately nodose and zigzag in old age, as is characteristic of this genus. It is not distinguish- able from EF. pierdenale except in the sutures. 'The lateral saddles and lobes are smaller than in any other species of this genus, and the first lateral saddles are apt to have the inner marginal saddles tongue-shaped. This peculiarity is noticeable in Bohm’s figure and in the large fossil (Pl. XXIV, fig. 5). Age: Fredericksburg group [?], Comanche series, Lower Cretaceous. ENGONOCERAS COMPLICATUM n. sp. Hyatt. Pl. XXIV, figs. 6-8. This is founded upon a cast from near Austin, Tex. The whole diameter, partly estimated, is 73 mm., the outer volution is 39 mm., the umbilicus 9 mm., the volution opposite (estimated) 25 mm. By the cast alone this species could not be separated from Hngonoceras gibbosum, but the sutures are nevertheless entirely different. A better preserved specimen might, however, show some external characteristic distinctions. There are fourteen sutures visible on the outer volution; then comes a gap between 176 PSEUDOCERATITES OF THE CRETACEOUS. them and those on the first quarter of the same volution. The entire fourteen overlap, but the tenth, eleventh, and twelfth are nearer together than any others. The ephebic sutures on the first quarter of this same volution are well separated. There are eleven slender saddles and ten slender lobes on the left side. The first lateral is narrower than in any other species and bifid, with tongue-shaped entire arms; the second and third laterals are also entire and linguiform; the fourth to the ninth are phylliform and bifid; the tenth could not be seen; the eleventh was entire. The ventral lobe is narrower, deeper in proportion than in other ‘species. There is a smaller and contorted cast from Benbrook, Tex., with similar sutures so far as the bifidity of some of the principal saddles is concerned. It is very likely a variety of this species. The markings, so far as can be determined, are similar. The living chamber is about one-half of a volution, the last sutures overlap, and the shell was evidently in the gerontic stage. The third lateral saddles were bifid, the fourth was entire, the fifth to ninth were more or less phylliform and bifid, and beyond this none were visible. it differs from Protengonoceras emarginatum (Cragin) in having pro- nounced lines of tubercles along the ventro-lateral angles and its greater number of lobes and saddles, judging from the descriptions of that species. The characteristics of the venter and the size as given by him indicate a larger species, with venter more like that of Proten. gabbi. A small specimen, a cast, from 15 miles west of Denison, Tex., has a diameter of 46 mm.; outer part of volution is 23 mm.; transverse diameter, 11 mm.; umbilicus, 7 mm., and opposite diameter from line of involution to venter, 16 mm.; transverse diameter, 7.5 mm. This has same shape of venter and general aspect. The nodes of the inner line are present as elongated coste, most prominent at the umbilical shoulders and much inclined orad. These disappear as they pass the centran lateral surface. Nodes could not be seen nor felt over the perfect surface of the cast, and none were visible at the beginning of this volution on a small bit of the shell of the venter exposed by excavation. The sutures in this specimen are crowded together unusually close for shells of this genus, the inner lobes and saddles overlapping slightly, beginning with the third lobes and fourth saddles. It is probably a ENGONOCERATID i. Head dwarfed form of this species, since in the earlier parts of same volution the sutures are well separated, as in other forms. The ventral lobes are obliterated, but sufficient of the first lateral saddles remain to show that they were equally bifid and that the outer arm was also bifid the inner arm entire and quite large. The second to fourth saddles were, on the left side, broad and entire, the fifth to seventh symmetrically and deeply bifid. Locality: Near Austin and Benbrook, Tex. Age: Fredericksburg group, Comanche series. ENGONOCERAS EMARGINATUM (Cragin)." Sphenodiscus emarginatus Cragin, 1893, Geol. Sury. Texas, Fourth Ann. Rept., p. 245. According to Cragin’s description, this species has the concave venter until a late stage, but has the tubercles and sutures of this genus. EINGONOCERAS ROEMERI (Cragin). Sphenodiscus roemeri Cragin, 1893, Geol. Sury. Texas, Fourth Ann. Rept., pl. 46, fig. 1. Cragin describes this shell as having ‘‘venter narrowly truncate, the ventro-lateral angle at first sharp, becoming on the body-chamber subtu- berculate-sinuous.” This and the general outlines of the sutures, if they are supposed to be deprived of their marginal saddles, as they must have been in the young of this shell before these were developed, has caused me to refer the species provisionally to this genus The sutures are, however, obviously more complex as figured by Cragin than in any other known form of Engonoceras. The principal saddles are all bifid, trifid, or quadrifid, and the smaller saddles inside of what appears to be the fourth saddles are mostly bifid. Mr. Stanton has written as follows regarding this form: According to Cragin, this is from the ‘‘alternating beds”—that is, the Trinity division—not Fredericksburg, as given in your MS. If this be true (and Mr. Taft’s stratigraphic data look all right), the form is probably the oldest one of this group that we have from the Comanche series. Locality: Iredell, Bosque County, Tex. Age: Comanche series, Glenrose beds. “See p. 157, where this species is doubtfully referred to Protengonoceras.—T. W. S. MON XLIV-—03: 12 178 PSEUDOCERATITES OF THE CRETACEOUS. NEOLOBITES Fischer. The sutures of this genus have, perhaps, simpler outlines than those of any other Cretaceous ammonoid, and have been supposed to place the genus somewhere near Tissotia. They, however, differ decisively from those of any of this group in having long phylliform saddles and a very peculiar ventral lobe. The form, ornamentation, and old age of the species from Tunisia, described by Peron, would place it in the genus Placenticeras, if no sutures were visible. But the sutures and ornamentation agree with those of Engonoceras, and show that it is probably a member of the same family. Choffat’s researches have placed this conclusion on a secure footing. His Neolobites vibrayeanus may not be identical with d’Orbigny’s species, but it is surely a close ally, and he gives the sutures in full, and these show the ventral lobes and siphonal saddles and first laterals to be similar to those of Engonoceras. If the young, when seen, prove to have a similar development, the evidence will be complete. NEOLOBITES VIBRAYEANUS (D’ORBIGNY). Ammonites vibrayeanus VOrbigny, 1840, Terr. Crét., pl. 96, figs. 1-3. Neolobites vibrayeanus Choftat, 1898, Faune Crét. du Portugal, Vol. I, 2d series, pl. 5, figs. 2, 5 (not figs. 3, 4.) This species as figured by d’Orbigny has led to great confusion, owing perhaps to the absence of a sufficient representation of the details. Choffat has figured a species from Portugal which, if not identical, is probably similar to @’Orbigny’s species. All the characters coincide with the posi- tion here given to this form. A number of species are confused under this name, but the data given are not sufficient to separate them. Locality:. France and Portugal. Age: Cenomanian. NEOLOBITES CHOFFATI n. sp. Hyatt. Pl. XXV, figs. 1-4. Neolobites vibrayeanus Choftat, 1898, Faune Crét. du Portugal, Vol. I, 2d series, pl. 5, figs. 3, 4 (not figs. 2, 5.) This is obviously distinct from vibrayeanus, as is shown by the broad venter and distinct sutures as well as the more gibbous form. Locality: Portugal. Age: Cenomanian. ENGONOCERATID &. LETS) NEOLOBITES PERONI n. sp. Hyatt. Neolobites vibrayeanus Peron, 1890, Moll. Crét. de la Tunisie, pl. 18, figs. 1, 2 A highly compressed shell with narrow flat venter bordered on either side by a line of small, closely set tubercles with numerous cost on the flat sides, focussed into a very few large nodes near the umbilical shoulder. The involution is almost if not quite complete. The umbilicus is not figured in Peron’s figure, but it must have been very small. In extreme age these nodes recede farther from their first position, the ventro-lateral lines of small tubercles disappear and the venter becomes elevated and is represented in the last stage as subacute. ‘There are five or six lateral saddles in this species, according to Peron’s drawing. Peron considered this form to be distinct, but did not describe it as a new species. Locality: North Africa. Age: Cenomanian. METENGONOCERAS n. gen. Hyatt. The shell is compressed as in Engonoceras and the involution covers the greater part of the sides of the internal volutions. Broad, fold-like sigmoidal costz are present in some species and faint tubercles have been observed in rare cases on casts. No well-preserved shells have been so. far seen nor described. The venter in the neanic stage is comparatively broad and slightly concave; in the ephebic stage it becomes very narrow, but retains a linear concavity; in the full ephebic stage it becomes acute, and in gerontic stage subacute and then rounded. The sutures do not differ materially from those of Hngonoceras; the distinction, so far as known, lies in the development of the venter and absence of nodes. The young were similar to the adults of Protengonoceras, as are those of other genera. The principal or outer lateral lobes and saddles are short, the lobes narrow and entire between the entire and more or less rounded, often phylliform bases of the principal saddles. The apical ends of the lobes are denticulated, but the marginals are entire, pointed, and the saddles blunter but also entire. The smaller inside of the principal outer saddles are often bifid. The ventral lobe is narrow orally, very short and broad apically, with two entire arms, and is divided by a depressed but more or less subacute entire siphonal saddle. he first lateral saddles in most species are broad and 180 PSEUDOCERATITES OF THE CRETACEOUS. bifid, the outer arms more or less acute at the outer angles of the bases, and the inner arm narrower and tongue-like. One of the marked characters of this genus is the absence of differentiation between the parts of the suture at later stages of growth. The principal lateral saddles and lobes can not in many specimens be distinguished from the so-called auxiliary laterals, and I have not attempted to do this in my descriptions. In some specimens, on the other hand, especially young ones, there seem to be plainly only three principal lateral saddles or lobes, but in others there seem to be four or even five. The metaneanic substage in one species showed the primary division of the primitive first lateral saddle into three, and in several specimens in a late neanic substage it seemed obvious that this subdivision was maintained and that the first lateral of the derivative or principal series became bifid late in the life of the shell. First lateral saddles are therefore morphologically double, even when they are so fully divided that they have to be considered as two saddles, as in Metengonoceras dumbli. In most species there is no difficulty in seeing ‘this, but in about all of them the line between the three principal laterals and the auxiliaries can not be drawn, nor between the principal lobes and the auxiliaries. Here, however, as in Engonoceras, there are but three principal laterals, if the first lateral is properly defined as double or bifid. The subacute venters of the species in this genus have lead to confusion with Sphenodiscus and its allies. The ontogeny of the latter separates the two generically, but the latter might be considered an accelerated form of the same family, as stated above in the description of the family, but for the sutural characters which show that Sphenodiscus belongs in the Placenticeran stock. METENGONOCERAS INSCRIPTUM n. sp. Hyatt. Pl. XXV, figs. 5-9; Pl. XXVI, figs. 1-4. One entire cast is 80 mm. in diameter. The diameter from line of involution to venter is 42 mm. at largest part, the transverse being 16 mm. Both measurements are a trifle short of what they would be in a more perfect cast. Opposite this the same diameter is 29 mm. without shell, the umbilicus being 9 mm. A fragment somewhat younger from same locality was not compressed so as to destroy the shape. This had the same form, but was not so con- cave near the umbilicus and had no folds. The volutions were flat on the ENGONOCERATID.®. 181 venter in the neanic stage, and were obviously similar to Protengonoceras in their young. The smaller fragment, nearly one-half of a volution, with center partly preserved, is 52 mm. in diameter, and the venter is worn, but in places where sutures are perfect the venter is narrowly rounded. In the largest cast, at about the same age, I was able to demonstrate by excava- tion that the shell, although very narrow, was thick and distinctly concave on the venter. There were apparently no large tubercles at any stage. The first lateral saddles in the small fragment, at a diameter of over 52 mm., were broad, very short, and had the inner angle furnished with a large marginal lobe and saddle. The second to fifth saddles on the right side, and the second to sixth on the left side, are entire, the sixth on the right and seventh on the left being the first of the bifid saddles. The other saddles are all bifid, except, perhaps, the innermost pair, but this was not seen. The lobes are too much worn down to show their minute digitations except in a general way. ‘The ventral lobe and minute median saddle are present and the first lateral saddles are narrow. On the youngest and least-worn part of the larger specimen on the right side, the first lateral saddles show slight marginal lobes and saddles at each of the inner angles, but there are minute marginal lobes on the outer parts of these saddles. Several of them show this division, and one is distinctly tritid. On the older parts of the same specimen they are, however, distinctly entire as in the other fragment, and this I think is the normal character. The wearing to which it had been exposed caused me at first to count three entire saddles on the left side and four on the older parts of the same volution. It is obvious, however, that it is the sixth saddles that are bifid on both sides. The remaining saddles are bifid to the line of involution. In both of these specimens there are ten saddles and nine lobes, but there was probably in each a lobe on the line of involution. The youngest sutures were about 5 mm. distant, but the last nine lost distance rapidly and were more or less irregular, and in the last four the second lateral saddles overlapped slightly the second lateral lobes. The larger cast has three much-worn fragments of the attached valves of an ostrean on the right side, which had evidently been exposed above the calcareous mud while in the same condition as at present, namely, a distorted fossil cast, and the ostreans grew upon the surface of the cast, itself. That the cast had already suffered from attrition and compression 182 PSEUDOCERATITES OF THE CRETACEOUS. was shown by the accurate fitting of the ostrean shells into the irregularities of the broken and worn surface. A few other lower valves were removed to study the sutures, but in no case could | find any remnants of the shell of Engonoceras between the bases of attachment of the lower valves of the ostrean and the surface of the cast. The specimens still left upon the cast show these facts also. The smaller specimen was much smoother and clean. A much-distorted fragment from another locality, 9 miles from Austin on Beecaves road, of what seemed to be the gerontic stage of this species is 85 mm. from line of involution to venter and this is very near to the actual diameter in a perfect cast. The greatest transverse diameter is 35 mm. and is somewhat greater than in a perfect cast of the same age. This specimen, however, has the sutures well shown on the right side, and the differences, with one exception given below, when compared with the first specimen described, can be accounted for as probably due to greater age. The saddles and lobes are all much nearer together, the overlapping begin- ning between the third saddle and second lobe. The curvature was the same as in the smaller specimen. The tenth saddle is the first bifid one and the remainder are bifid and near the umbilicus become very broad. This difference can not be accounted for by supposing that the seventh and eighth saddles have become completely divided by the advance in development of the marginal lobes, thus adding two saddles to the series, but indicates some original variation in this shell. The ventral lobe could not be defined and the condition of the other lobes only enabled an observer to see that they were digitated and near the umbilicus they were too much worn to say even this much. The length- ening out of the saddles by growth does not decrease the phylhform aspect of the bases and the lobes become narrower and longer without apparently altering much in general outline. Locality: Twelve miles northeast of Decatur, Tex. Age: Fredericksburg group, Comanche series, Lower Cretaceous. METENGONOCERAS INSCRIPTUM var.? This is a fragment of a volution of a large specimen, showing only a part of one side. It is, however, interesting, for the characteristics of the lobes and saddles given on Pl. XXV, fig. 8, show variations iu the forms of these. A specimen from west of Walnut Springs, Tex., kindly loaned me ENGONOCERATID 2t. 185 by Professor Cragin, shows the subacute venter. he eighth saddles are bifid in this fragment and there are only ten on the right side, with large unequally bifid first laterals as in large fragment described above. Locality: Fifteen miles west of Denison, Tex. Locality 1492, U.S. Geological Survey. Age: Fredericksburg group of Comanche series. One fragment is 55 mm. from line of involution to venter without the shell. he first lateral saddle is deeply bifid, and, counting this as one, there are only five entire saddles, some of which, probably owing to wear, appear to show a faint tendency to become bifid. The sixth to the ninth saddles are distinctly bifid; the tenth is a very broad saddle with three minute marginal lobes, and the eleventh is another broad saddle which is entire to the line of involution. On the opposite or right side the broad tenth saddle is divided into two bifid saddles, so that there are obviously twelve on that side. Locality: Cow Creek, Travis County, Tex. No. 19105, U.S. National Museum. METENGONOCERAS AMBIGUUM n. sp. Hyatt. Pl. XXVI, figs. 5-7. One nearly entire cast of this form is 79 mm. in diameter, the last volution 44 mm. from line of involution to venter, the umbilicus 6 mm., and the opposite part of volution 29 mm. The greatest transverse diameter through median surface is 17 mm. and is somewhat less than in a perfect specimen. : The sutures have smaller saddles than at the same age in M. inseriptum, are also less distant throughout, become still more approximate in later stages, and are straighter. There are thirty septa in this specimen to twenty- four in inscriptum at same diameter. The sixth saddles were bifid on both sides. Fold-like costz along the inner part of the volution are plainly visible and there are small nodes along the ventro-lateral angles, the venter being here famtly sinuous. The venter was much eroded, but in two places it showed a narrowly rounded area and on the end of this volution is subacute. Excavation was not very successful and I could only demonstrate that the venter was extremely narrow in the ephebic stage and perhaps not distinct from that of Eng. inscriptum at the same age. 184 PSEUDOCERATITES OF THE CRETACEOUS. This cast was considerably worn. The right side was free of encrusting ostreans; on the opposite (left) side there were a few, some of which were removed. No shell was found between these and the cast. They had evidently grown upon this cast and not upon a living or dead shell. This can also be seen by studying the remaining shells, one complete lower valve and part of another. Locality: Nine miles from Austin, Tex., on the Beecaves road. Age: Comanche Peak limestone, Fredericksburg group of Comanche series, Lower Cretaceous. METENGONOCERAS ACUTUM n. sp. Hyatt. Pl. X XVI, fig. 8; Pl. XX VII, figs. 1,-2. The type specimen of this species in Boll collection in the Museum of Comparative Zoology is a fragment, but this shows the whole diameter to have been approximately 100 mm. ‘The outer volution from line of involution to venter is 54 mm, the umbilicus 5 mm., and the same volution opposite must have been about 40 to 41 mm. The form is much compressed and involute, with more acute venter than in M. inscrivtum. The umbilical shoulders also in this species are more prominent and entire, and short but distinct, broad, fold-like costze are present near the umbilical shoulders, but do not cross them. There are no tubercles on the fragments observed. The marginal lobes of the first lateral saddles on both sides are narrow and divided by a minute marginal saddle or bifid. he first laterals are unsymmetrically trifid, the second to the fourth are symmetrical and quad- rifid, the fifth is of the same type but not regularly divided. All of these are very narrow at the bases between the expanded bases of the saddles and spread out apicad into the marginal divisions. The sixth lobe is narrow and bifid, with a small marginal saddle, and the seventh similar, but with a larger tongue-like marginal saddle, and the minor lobes on either side of this are also subdivided or bifid. The eighth and ninth are distinctly but very faintly trifid, and much longer than the narrow marginal lobes — described above as dividing the broad saddles of this part, which are faintly bifid. The tenth lobe was visible but not distinct enough for description. Both specimens were too much crushed in the central parts to give any accurate data for the description of the younger stages. Nevertheless ENGONOCERATID®. 185 there are strong indications that the venter became acute in an early ephebic substage. The matrix of these specimens is a red, apparently calcareous, clay stone, and indicates a distinct formation from that containing the species of Placenticeras cited from the same locality and also in the Boll colleetion in the Museum of Comparative Zoology. They have remnants of the nacreous layer and one has the shell still left in the umbilicus. The interior is so much crushed together that it is impossible to say that the venter was or was not concave in the internal volutions. Certainly, so far as the cast goes, the outer volution was unquestionably subacute. Three fragments in Cragin’s collection from the Grayson marl, one- half to three-fourths mile southeast of the Union Station, at Denison, Tex., have the phylloidal saddles and long complex lobes of this species and also subacute venters. The last volution of one of these fragments reaches ventro-dorsal diameter of 60 mm. while still septate, and has a transverse diameter of 24 mm. The sutures, however, are too much abraded for efficient observation. The peculiar first lateral saddles of this species, the extremely phylli- form saddles, narrow lobes with spreading and digitate extremities, and straightened sutures, separate this from M. inscriptwn. The larger size of the lobes and saddles enables one, as well as the more persistent acuteness of the venter in the gerontic stage, to distinguish it from M. dwmbli. Mr. Stanton has written as follows with reference to this fossil: “TI think this is certainly from the Upper Cretaceous and probably from the Eagle Ford shales, like the other specimens with the same locality label. Such brownish-red concretions are common in weathered portions of the Eagle Ford shales.” Locality: Elm Fork and West Fork (Horton’s mill), Dallas County, Tex. Age: Probably Eagle Ford shales, Colorado group, Upper Cretaceous. METENGONOCERAS DUMBLI (Cragin. ) Pl. X XVII, figs. 3-14. Sphenodiscus dumbli Cragin (pars), 1893, Geol. Surv. Texas, Fourth Ann. Rept., p- 243, pl. 44. A superb specimen in collection United States Geological Survey, diameter 94 mm., although in three pieces and with nepionic stage and part 186 PSEUDOCERATITES OF THE CRETACEOUS. of outer volution absent, is otherwise perfect and shows many essential facts with regard to the affinities of this genus. The last half of outer volution or greater part of living chamber is in the gerontic stage. This shows that the living chamber was at least one half of a volution inlength. Cragin, who had this cast in hand as part of his materials, describes his specimens as being ‘very sharp in the young [my adult], becoming obtuse along the body- chamber of adult [my old age] specimens.” The well preserved part of the gerontic venter in this cast is 23 mm. long and for a few millimeters is rounded, with two almost imperceptible ridges on the ventro-lateral angles, then a hollow occurs as if the shell had been injured, and this is continued to the end of the fragment by a very faint channel bordered by faiut ridges. The young in the nepionic stage has the usual rounded volution; the paraneanic substage was compressed with flat sides, deep involution, and broad concave venter, with entire, acute ridges on the borders. This stage is, in other words, like the ephebie stage of Protengonoceras, as has been already stated from examination of less perfect specimens. This substage was introduced gradually by the intervention of a metaneanic substage having a helmet-shaped section with a flattened venter and an ananeanic substage with transitional characters between this and the nepionic rounded volution, but not having the flattened zone on the venter. In the anephebic substage the compression and flattening continues to increase, the mvolution remains constant, and a very narrow channel still persists on the venter. In the full ephebice condition this disappears and the venter becomes acute. In the paraephebic substage the venter is subacute, the sides a trifle more convex, and volution somewhat broader in proportion to the ventro-dorsal diameters, but these changes are slow until in extreme age, the paragerontic substage, when, as stated above, the venter becomes rounded. I have frequently alluded to the remstatement by degeneration at the end of a cycle or in the adult of characters analogous to those of younger stages. In this specimen the rounded venter of the paragerontic substage has a faint concavity, and this, after what seems to have been some injury to the edge of the venter, becomes converted, as described above, into a faint channel with ridges on the outer borders. There are no marks of tubercles, nor coste, nor folds at any stage so far as these could be seen. ENGONOCERATID &. 187 The sutures have short broad saddles with narrow lobes, digitated only at the apical ends, and while the saddles remain about the same, the lobes imerease somewhat in the number of their digitations and in length with age. They are quite different on the right and left sides. The siphuncle is eccentric to the right, and ventral lobe follows this organ, but there is no very marked difference between the first lateral saddles in consequence of this. On the right side the first lateral has two branches so deeply divided by a bifid marginal lobe that it is really split into two distinct entire saddles, but these are more widely separated than in Meteng. acutwm, and are more nearly equal in size and aspect. Counting these as two saddles, there are thirteen saddles—ten narrow, entire, and phylliform, and three broad and bifid, the eleventh very deeply bifid, and the twelfth and thirteenth successively less deeply divided. The first and second lobes are bifid, the third to sixth bifid, but with four to eight digitations; the seventh to tenth simply bifid; the eleventh and twelfth, especially the eleventh, are divided by longer tongue-shaped saddles. On the left side the differences are as follows: The ninth to eleventh saddles are broad and bifid, the twelfth is broad and entire, the thirteenth is very broad and has a sinuous base, and inside of this a very minute lobe shows that there is a small fourteenth saddle. The eighth to the tenth lobes are simply bifid, the eleventh is unequally bifid, but has no long tongue-shaped marginal saddle; the twelfth is entire, and there is an excessively minute marginal thirteenth, as stated above. In the adult stage from the fifth saddles inward on both sides the sutures overlap slightly and the outlines are easily separable, but in the last five sutures this overlapping spreads to the third saddles and lobes and the out- lines are more compressed. This is accompanied by a shortening up of the saddles and lobes and a corresponding return of the younger proportions and aspect. In the metaneanic substage the primitive first lateral is divided into three low broad saddles by simple indented marginal lobes, and the magno- sellarian saddles are also divided, but the number of these was not ascer- tained. There were, however, only a few of these. Locality: Four miles east of Whitesboro, Tex. Age: Eagle Ford shales, Colorado group, Upper Cretaceous. 188 PSEUDOCERATITES OF THE CRETACEOUS. PLACENTICERATID& Hyatt. The young are similar to the adults of Engonoceratidee, having con- cave venters bordered usually by continuous ridges with compressed volu- tions, the lateral zones converging outwardly. In later stages of genera the venters are either concave, flat, or rounded, but there is no true keel present, although the venter may become acute in some species at a late stage of growth. The volutions in the earlier stages subsequent to the nepionic are apt to be more or less compressed, the venters assuming early the characters described above, any further sharpening of the venter occur- ring in later stages. The principal lateral saddles are, so far as known, bifid in the young and show in most groups a tendency to become more or less trifid in later stages. The multiplication of inflections of the suture lines increases with the involution of the whorls by growth and they become very numerous in some genera. PLACENTICERAS Meek. The species of this genus could be readily distinguished if it were not for the great range of form in the gerontic stage, which occurs in dwarfed as well as in large specimens, and is continually mistaken for the ephebic stage. The neanic shell is smooth, compressed, with at first a flat and then a concave venter bordered by smooth, entire ridges on the shell and on the casts, but has a stouter volution than later stages. It is, in other words, like the ephebic stage of Protengonoceras in external characters, but the sutures are of the Placenticeran type. Subsequently the ridges become tubercu- lated, the venter becomes much narrower and the sides also tuberculated and the volutions more compressed. These spines, nodes on the casts, are in three rows, but may be completely absent in some shells, as they are also in some old shells. In old age the venter again becomes flattened and smooth, and finally broader and rounded. The species are all connected so closely by intermediate forms that distinct lines are difficult to draw between contiguous species. The compressed and highly involute young show that those species, like P. guadulupe, having depressed volutions with broad venters, are senile forms in the phylum, or what I have named phylogerontic. ‘They PLACENTICERATIDZ. 189 are not seaphitoid, as stated by Munier Chalmas, except in the sense that Scaphites is an extreme case of the same tendency to reproduce senile char- acters early in the ontogeny and to such an extent that the ephebic form becomes more or less influenced by them. The species form a series, there- fore, leading off from shells, like P. syrtale in one direction into P. guada- lupe and in the other into whitfieldi. The intermediate modifications connecting this genus with Protengonoceras are probably partly represented by Diplacmoceras, but this genus is not a primitive, although it seems to be a phyloneanic form. The solution of the species problem appears to lie principally in the development of tubercles and the correlative stoutness of the volutions. Shells having heavy tubercles in three lines usually also have sutural pecul- larities that enable one to distinguish them. The peculiarities of the gerontic stage are also distinct, as will be noticed in the descriptions. In some spe- cies the neanic stages are quite distinct in their sutures, although alike in their forms at the same age, and perhaps with more materials the study of these and the development of sutures may give good results. The most highly modified form as compared with its own neanic stage is certainly guadalupe, but although the sutures are complicated in outline, they are not so complex as those of whitfieldi, and the modifications of form are distinctly in a phylogerontic direction. The varieties of each species and the development poiut to the most prevalent syrtaloid form as presenting more than any other purely progressive characters. This form has moderately compressed involute whorls, with three lines of nodes, narrow venter, and steadily complicating sutures. The same variations in the species and in the individual point consequently in one direction toward guadalupe and in another toward whitfieldi. This last is reached through species like stantoni and pseudoplacenta, 11 which the median lines of tubercles become permanently obsolete and the outer and inner lines become less prominent and in many specimens of whitfieldi are absent, The interesting fact in this connection is that whitfieldi, which, as compared with its own young, is the least modified of all the forms, has the largest shells, the least affected by gerontic degeneration, and at all stages the most complex sutures. These facts also show in a marked way the law of retardation of development. This was joined by Cope with acceleration, but so far as 190 PSEUDOCERATITES OF THE CRETACEOUS. my experience goes they are quite distinct. Retardation occurs in cephalopods in phylogerontic forms. Thus in this phylogerontic genus the young is a highly modified, compressed involute shell in the neanic stage; the adult in some species like guadalupe and the Kuropean depressum may have additional modifications ending with a paragerontic stage also tuberculated, but with peculiar broad venter and lateral nodes. In other species, obviously closely connected, like pseudosyrtale, newberryi, planum, and European congeners like grossowwret and milleri, the first appearance of tubercles occurs later in the ontogeny and they are present in their full development only in the latest ephebic substage or gerontic stage. The same law holds also in the series leading from syrtale through intercalare and stantoni to whitfieldi. In some forms of syrtale and intercalare the three lines of tubercles appear eartier than in the typical forms of the same species and in placenta. In stantont and pseudoplacenta this later appearance of tubercles becomes invariable and correlates with the disappearance of the centran line and a tendency to decrease in size of these ornaments on the venter and umbilical shoulders. In whitfieldi this tendency results in the total disappearance of the tubercles in a large number of shells, three lines of tubercles being present only in a very few shells and always of very small size, plainly individual reversions. The sutures are simpler in outline and continue persistently to hold the syrtaloid outlines, and are easily separable, except in extreme age, in all of the guadalupan series, including not only the stouter forms like guadalupe, but the highly compressed shells like planwm. In the series leading up to whitfieldi there is a marked gain both in complexity of outline and in gerontic characters. This is apparent in intercalare and placenta, which still retain the three lines of tubercles, and is still more pronounced in stantoni and pseudoplacenta and culminates in whitfieldi. In these last the sutures are similar to syrtale only in the neanic stage, and in whitfieldi they become more rapidly complex in ontogeny than in other species and overlap to such an extent that it becomes more difficult to separate them throughout the ephebic and gerontic stages. This overlapping is a purely gerontic character, and the species that show it during the ephebic stage are therefore phylogerontic and to this extent degenerative in spite of the PLACENTICERATID®. 191 increase in complication of outlines of the lobes and saddles and their large size. This phylogerontic character is also accompanied, as stated above, by loss of ornamentation and retention throughout life of the compressed, involute, smooth volutions of the neanic stage. The living chambers are persistently one-half of a volution in length, whether occurring in depressed or compressed shells or in dwarfs, and the apertures, so far as seen, have a short, blunt rostrum and low, broad lateral crests. Grossouvre’s careful descriptions and exceptionally fine figures of the different forms included under the name of Placenticeras syrtale show that while there exists in France and Germany a series closely parallel to that of guadalupe, sancarlosense, newberryi, pseudosyrtale, and planum in this country, all of the European shells present differences showing that the evolution of the modifications was distinct in France. The geroutic stages show a greater tendency on the part of the inner lines of nodes to grow farther out on the lateral zones and approximate to the venter, and the venter not only flattens out to a plano-convex outline, as in some American species, but also in a subsequent gerontic substage, as in P. grossouvrei and milleri, becomes more or less concave. This is due to the increasing size of the tubercles of the median line on the borders of the venter after the disappearance of the ventral lines of earlier stages. Kossmat® sums up the literature of the genus Placenticeras and its allies. The type of the genus Buchiceras is erroneously considered as a species of Schloenbachia. Schloenbachia is a genus with normal outlines to the sutures, a decisive keel with channels or smooth bands on either side, and more or less sigmoidal, prominent, well-developed cost, the aperture having a long, pointed rostrum correlating with the keeled venter. The development is also very distinct from that of any of the Pseudoceratites of the Cretaceous. In preceding pages, B. bilobatum is jomed with other related species, and the differences of the series to which it belongs can be more readily seen. Kossmat’s strictures with regard to my own work on this group are just and most of bis objections well founded. His reference to baldwi Keyserling, as the probable radical of Placenticeras may be correct. At any rate there are some facts that favor this. The sutures are similar to those of Placenticeras. The young of this species certainly aSiidind. Kreidef.: Beitr. Pal. und Geol. Osterreich-Ungarns und des Orients, Vol. IX, 1895, p. 171. 192 PSEUDOCERATITES OF THE CRETACEOUS. resembles that of some of this genus in having a channeled venter, but it is much too involute and compressed for a primitive type. The keel of balduri is developed in the center of a broad, concave venter of neanic age, as an obtuse raised area, but finally the entire venter becomes elevated with a subacute carina, like that of Buchiceras. v * - i, - 2 ee 3 a . : CPLATH 1 i S, i Z % : ‘ LEG AI IOI ROEMEROCERAS, PARATISSOTIA. TGS ISP ROCMEROCERGSYG CLD Un selay Utter yas se ates ee Figs. 1, 2. Natural size. 3. Enlarged suture. Coll. Acad. Nat. Sci. Philadelphia. Quebrada de Colpamayo, Peru; Upper Cretaceous; all after Gabb. EGS 4G el OTERO GENASRSLUD DLANILUTI Lay eUU Umer ei te se erates eer Figs. 4, 5. Natural size. 6. Suture, x 2. Cajamarca, Peru; Upper Cretaceous; my collection. Inicekee Fill, JRemoidasaneaarnee, (WKN) sosatesoscconcocsosceessabasecconscsscuccseesce Figs. 7, 8. Natural size. 9. Fig. 8 enlarged. 10. Center of fig. 8 enlarged to show section of young and solid keel. 11. Lateral and dorsal suture of fig. 7 above the break. Cachiyacu, Peru; Upper Cretaceous (Senonian?); my collection. 256 Page. U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV ROEMEROCERAS, PARATISSOTIA. oe ig Ea yw Cd aes f nt Pel Ure, Wee “Mon x~IV—03——17 PINAL 1 ICICIC, PARATISSOTIA, SPHENODISCUS. Figs. 1-3. Natural size. The venter is restored in fig. 1, and in fig. 3 the hollow keel is restored except in lowest volution of section, which is as seen in fig 4. 4. Enlarged view of section of venter of lower whorl of fig. 3, showing hollow keel on its first appearance. 5. Suture of first quarter of outer yolution of fig. 2; dorsal saddles merely indicated. : ; 6. Much abraded sutures of last quarter of same, to show the number and general proportions of the curves; the ventral lobe is more deeply worn than the lateral. Cachiyacu, Peru; Upper Cretaceous; my collection. Hires: 7-15; Sphenodiscus pleunisepta (Conrad) 25-2 25222- 222222 e see ae ee ee Bey aaa sity Figs. 7-9. Natural size. Rio Pecos,(?) Tex.; Upper Cretaceous; Coll. Columbia University, New York, No. 10881. 10, Enlarged center of fig. 9. The sutures in this were not so clearly seen as to make the observation in this and fig. 12 entirely reliable. 11,12. Enlarged outlines of young of fig. 9. : 13. Older specimen than figs. 7-12, showing the rounding of the venter. Near Eagle Pass, Tex.; U. S. Nat. Mus. Coll. No. 19145a. 14. Loc. same, coll. same, No. 19145b. Same age as figs. 7 and 8, but showing more acute yenter and more prominent tubercles; this variation has been slightly increased by compression. 15. Suture < 24 of specimen represented by Pl. V, fig. 3. Rio Pecos, (?) Tex.; Coll. Columbia University, No. 10881e. All on this plate are casts. 258 59 US. GEOLOGICAL SURVEY MONOGRAPH XLIV. PL. II] PARATISSOTIA, SPHENODISCUS. Pebtyecs Abin dare Pay AN ae EE A IE I SPHENODISCUS PLEURISEPTA (Conrad). (Page 59. ) Fes. 1, 2. Loc. No. 1473, near Hagle Pass, Tex.; Upper Cretaceous; Coll. U. 8. Geol. Survey. 260 U. S. GEOLOGICAL SURVEY PL. IV MONOGRAPH XLIV SPHENODISCUS. ‘PLATE V. IPI AID be WE SPHENODISCUS. Fies. 1-3. Sphenodiscus pleurisepta (Conrad) Figs. 1, 2. Fig. 2 is restored in the lower part. The venter, where it is covered by the shell, is slightly more acute than is shown in the drawing. Near Eagle Pass, Tex.; Upper Cretaceous. Coll. U. 8. Geol. Survey. 3. Ventral view of same fossil as figured in PI. III, fig. 15. Coll. Colum- bia University, No. 10881e. Fie. 4. Sphenodiscus stantoni Hyatt Fig. 4. The sutures do not show very well in this, and an enlarged view of the first six saddles is given on Pl. VI, fig. 5. Same locality, age, and col- lection as figs. 1-2. iw) for} bo MONOGRAPH XLIV PL. V U_ §. GEOLOGICAL SURVEY SPHENODISCUS, na Pc Vee tt ie, Ae OI. SPHENODISCUS. Mies, I, 2, Syangooelisewis Karenos (Abra) 5-532 o-eastaose seus 0scessoccocosscc sassoyan cosas Shows the abnormally shortened living chamber and flaring abnormal aperture and partly absorbed sutures. Lander’s mill, Tippah County, Miss.; Ripley group; Coll. U. 8. Nat. Mus., No. 20577. IG SSeS LCMOCISCUS UCC LET Un kel oy reli typ ayes rage ste feat rte ee Birmingham, N. J.; Lower or Middle Greensand marls, Upper Cretaceous; Coll. Yale Univ. Mus., No. 200. ihe, |) Bp Swaeornnons Guemions lslyvening oo Seaeosckonteoossoece scot cesceeuceesess sess bsoceses Suture from specimen figured on Pl. V, fig. 4, showing the principal saddles and lobes, <3. ; WIGS wy OxmSphenodiscusipleumaseptay (Conia G)) jeter eee a Siben Buncombe Hills, Pontotoc County, Miss.; Ripley group, Upper Cretaceous; Coll. Frederick Braun. 264 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. VI SPHENODISCUS, Fe ite Rees GIP WIC IE, SPHENODISCUS LoBATUS (Tuomey). (Page 66. ) Fies. 1, 2. Pontotoc County, Miss.; Ripley group, Upper Cretaceous; Coll. U. 8. Nat. Mus., No. 2408, $ natural size. 266 MONOGRAPH XLIV PL. vil U 8. GEOLOGICAL SURVEY SPHENODISCUS, a Dy) PIb.2N a, VW UUL PIG AN IS, Wb IE It SPHENODISOUS. Page Fias. 1, 2. Sphenodiscus lenticularis (Owen) ..---------------- (ES alates) SNA ate ae Me eee Sorte 71 Fig. 1. Young of supposed typical form, natural size. See also Pl. IX. 2. Suture of same 64. Moreau River,? Dakota; Fox Hills group; Coll. U. 8. Nat. Mus., No. 7754. WIGS Siem SPRENOCISCUSs LENSUCULLG MLS a\felicanS 0 LENO CLENS ile oy rel tps saan eet as =a en eT > Figs. 3, 4. Views of fragments showing lateral sutures and internal, loose younger yolution, natural size. 5. Dorsal suture of one side of about same age as the one painted in on fig. 3, natural size. 6. Antisiphonal lobe of fig. 5, much enlarged. : 7. First three saddles and siphonal saddle to show outlines on the next inner yolution to that of fig. 3, natural size. South Dakota; Fox Hills group; my collection. 268 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. VIII SPHENODISCUS, RAT. 1x ‘ ie i y PIL AWD Ne: SPHENODISCUS. Thee, I, Silaqaodhsens Uaoncullenns ((Ow@))——soo5ss cess eco Sse ssnccu SSeS se saeseocessosscosss Fig. 1. Suture of paranepionic substage, >< 25. 2. Details of siphuncle, showing what seemed to be a collar above and a pro- longed funnel reaching from the septum to the opening of the collar. 3. Sutures of the neanic stage, showing the division of the first primitive lat- eral into three saddles, first, second, and third of the later stages, and the mode of increase of the so-called auxiliary saddles and lobes on the line of involution, 5. 4. Section of the two youngest yolutions observed, >< + 4. 5. Lateral suture of later but not fully adult stage, 6. Dorsal suture of same age, 8. Rock Creek, Wyoming; Fox Hills group; Coll. Yale University, No. 1697. Fics. 7-9. Sphenodiscus lenticularis var. mississippiensis Hyatt _-..-..---..--------------------- Fig. 7. Lateral suture, natural size. 8. Dorsal suture of same age, but one-fifth over the natural size; actual meas- urement is 48 mm. instead of 60 mm., the length of the figure. 9. Lateral suture, natural size, from specimen in Coll. Acad. Nat. Sci. Phila- delphia. Three miles northeast of Ripley, Miss.; Ripley group; Coll. U. 8. Nat. Mus., No. 20863¢. ErGe lO Sp enaalescris eea vert eluyrctititey Seat ee eat eee sae reer Suture, natural size. Fox Hills group; Coll. Mus. Comp. Zool., Cambridge. ATG! SHLD SEs S 1) REMLOCUSCLUSHLO DCLLIOS (@ANUT C TAN y3) Nepemes ana aoe : Fig. 11. Right side. 12. First three saddles of left side at same age, natural size. 13. First three saddles of left side of the youngest suture shown on Pl. VII, fig. 1, natural size, for comparison with fig. 12. Buncombe Hills, Pontotoc County, Miss.; Ripley group; Coll. Frederick Braun, Brooklyn, N. Y. ~I ~I 66 U. S, GEOLOGICAL SURVEY MONOGRAPH XLIV PL. IX SPHENODISCUS. eA Te Li TEED) OX, CoILOPOCERAS, SPHENODISCUS. Wrasl—459 Coilopocenasmovimericanumpely alles ae eee eee eee ees 94 1-3. Natural size, showing hollow keel, etc. 4. One entire lateral suture and parts of two others, x 2. The terminations Figs. of the saddles were more or less pointed depressions in the cast and were not at first observed. Near Carthage, N. Mex.; my collection. Mrassip=2iley Colomocenas/ Goulet i alelay cutstie ete epee aes esata a yaar eee bn gee ne aa eee Pe reve 91 5, 6. Natural size, section partly restored; see also Pl. XI, fig. 1. Figs. oI Lateral suture same as in side view, x 2. The dorsal suture of same age, but a suture or two later. 9 9. Youngest suture shown in fig. 5, « 2, showing the marked changes that occur on this volution. 10. First to third suture of nepionic stage, >< 20. lla. An entire suture of latter part of first volution, >< 20. 11 13 14 . Two entire sutures of first quarter of second yvolution, X 20. . Entire suture of fourth quarter of fourth volution, x 8, when the sutures “are beginning to show subdivision. . The protoconch and part of the first volution, < 22, same age as fig. 14. . More enlarged side view of the same. 15, 16. An older stage of the same shows less of the protoconch and more sutures. 17, 18. A still older stage, showing the decreasing transverse diameter of the yolution in the goniatitic stage, and the first constriction or mark of a nepionic aperture. 19, 20. An older stage of same, center of fig. 6, and also of fig. 1, Pl. XI. 21. Shows the hyponomic sinus of constriction or permanent aperture given in figs. 18 and 19. The normal rate of growth and increase in diameters of yolution has begun in this nepionic substage. Near Carthage, N. Mex.; my collection. Fie. 22. [Suture of Sphenodiscns introduced for comparison.—T. W. 8. ] 272 x PL, MONOGRAPH XLIV U. S. GEOLOGICAL SURVEY COILOPOCERAS, SHPENODISCUS. = 273 PAA Be eXole CorLtorocrras, EuLopHocERAS, MrrToicocERAs. Section same as Pl. X, fig. 6, enlarged. NIG S42 OaeNeL UO DROCERASHLOLCLET SC ploy atl te a ese eae ae 86 Fig. 2. Side taken before specimen was ground to show section. 3. Section somewhat more than natural size, and somewhat restored, shows the umbilicus on the right completely filled by the shell layers. This filling occurs in the adolescent stage, inclosing the dark spots on both sides of the center, which indicate that the shell did not fill the umbilici at an earlier stage. 4. Enlarged view of center restored. 5, 6. Shows keel to have been solid at this age. 6a. Enlarged drawing of hollow keel of venter connected by a dotted line. Natal, South Africa; Cretaceous; Yale Museum. hes, (Os Wigner Senallond (SowwTe Wl) = 352 be ced eebaeceuasadaccsuocessesscausndasoeose 118 Fig. 7. Protoconch and part of nepionic volution, 56+, actual transverse diameter 3/10 mm. 8. Side view of same, showing the abrupt bend in the protoconch before the nepionic tube began to be formed, and the first two sutures. . Optical section of same along dotted line in fig. 8 and from front of view shown by the arrow. 10. Front view of the specimen before removal of the outer volution, x 36. 11. Enlarged view of the czecum and first section of siphuncle, showing also the ventral lobe divided by a siphonal saddle. 12,13. Neanic stage, showing the aspidoceran-like form and tubercles, < 6. 14,15. A little older stage with living chamber complete at the umbilical shoulder, over 1/2 volution in length, * 6. Back of this shows rounded venter of the neanic stage just becoming divided by the incoming of two rows of tubercles. 16,17. Early ephebic substage. 18. Sutures of fig. 12 about first quarter of fourth volution, « 12. 19. Suture of second quarter of same volution. 20. Suture of probably fourth quarter of same volution. 21. Dorsal suture of the second volution, x 12. 22. Dorsal suture of what was considered to be the last of fifth or part of sixth volution, < 12. 23. Dorsal suture later in age than fig. 22, « 12, of same age as suture Pl. XIII, fig. 1. 24. Lateral suture of fig. 16 enlarged 3 diameters. The ventral lobe has been distorted by setting the siphonal saddle at an eccentric angle. Texas; Colorado epoch; my collection. See P]. XIII for other figures of this species. We) U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL, XI COILOPOCERAS, EULOPHOCERAS, METOICOCERAS. Pee AW mean 2 75 Pa ek: COILOPOCERAS, ACONECERAS, SPHENODISCUS. Hriegsl—se Colopocenasispivng ents klnyeibtps se tart Secon a NEM ee a eae 96 Fig. 1. Suture of right side of shell. .2. Suture of left side. 3. Antisiphonal lobe and first dorsal saddle. Lower part of lobe below dotted line and right side is restored; the point, however, was seen to be bifid. All natural size. Rit du Plain, Colfax County, N. Mex.; Colorado epoch, Upper Cretaceous; Coll. Mus. Comp. Zool. BirGs)4—6 5 eAlconecenas:nistinyn (Or; nig ricyp) mee ase eee eee eee 100 Figs. 4, 5. Natural size (after d’Orbigny’s figures) . 6. Sutures enlarged, showing similarity to phylloceran outlines. GM COUOMOCERASNG MOSS OLN: Gls sly ci Lies se ae eee 100 Figure of supposed Sphenodiscus requienianus d’Orb., showing coilopoceran suture. (After Grossouvre. ) WIGHSwrS Denod IsCcUsTKONINGcipely albu pee e sense se eee eae see eee eee 82 Fig. 8. Suture natural size. Part of one suture is shown and this is continued by the auxiliaries of the next suture below. Near Maestricht; Senonian; DeKoninck Coll. Mus. Comp. Zool., Cambridge. 276 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XII COILOPOCERAS, ACONECERAS, SPHENODISCUS. ae Ie su) y ry aire it i : - \ ) by. ‘ a iH Sant ; pes fl : yp i Cont te no. } Ds ig ; : ath i 4 3 My 4 ; ¢ ; iF i ; : en we) 7 PLA) XGh ie ae all y ‘ ; | . 7 3 i ‘ fh ate t " : IP I AL hy XIII, MeETOICOCERAS. EMG Sale PamVMELOUCOCEN CLS? SUUCLLLOt I (US LNT eam: ClO) tees ee eee eee reo 118 Fig. 1. Same as Pl. XI, figs. 20-23. First three saddles and two lobes of lateral suture, X 12, to show mode of division of saddles and their distinct marginals at this late neanic substage. 2. Grayson County, Tex; Coll. D. 8S. Martin. EGS eio=psMCLOUGOCEN CIS WAU ILE Cy lly yieLU Ue aes et aaa eee 122 Fig. 3. Shows shell on part of outer volution and how little this differs from the cast. 1 4. Shows this also as well as the rounding of the living chamber on the venter in old age. See also younger suture from opposite or left side; Pl. XIV, fig. 10. 5. Last suture of another specimen of about the same size as fig. 4. Upper Kanab Valley, Utah; Coll. U.S. Nat. Mus. U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. Xill METOICOCERAS. PIG AO I QIN MeErorcocERAs, VASCOCERAS. Wie, Ue) WOKCOGARaS NAD IBLE oo doo soca bcosonsodgcuesocecasasueasee keepeaeuseoseces 122 Figs. 1,2. Exterior, natural size, showing living chamber nearly three-fourths of a volution in length, complete to its inner border. 3. Lateral suture of the last septum, > 3. Elm Fork, Horton’s mill, Dallas County, Tex.; Colorado epoch. 4,5. Specimen somewhat older than fig. 1, natural size. Probably from Texas; my collection. 6. Lateral suture, X 3. Living chamber, probably nearly complete, is one-half of a volution in length. 7,8. Type of species, natural size. 9. Suture, natural size, somewhat older than fig. 4, whole diameter about 56 mm. Elm Fork, Horton’s mill, Dallas County, Tex. 10. Lateral suture, left side of fig. 4, Pl. XIII, taken from halfway between the base of the living chamber and the opening of the same. Hig se lela eMetoicocenas accelenaywmpely abe ee eee eee eee eee sener eee eee eee ere eee eee Wet Len Figs. 11-13. Specimen in which the living chamber is complete and over three- fourths of a volution in length, natural size. 14. Part of suture visible at base of living chamber on the opposite side to that figured, > 4. Elm Fork, Horton’s mill, Dallas County, Tex. Bre. sn Metorcocenas whiten ely attenm see meses eee eee ee eee ee eee eee eee ee eee 122 Dorsal suture, natural size. Elm Fork, Horton’s mill, Dallas County, Tex. Bree) Gs Wascocenastiucmttiy (ely att) ee Ue Ue s/t sey. yes Sy aie aN Se see eterna Cope etey Eee epee ape 103 Suture, natural size. 280 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XIV METOICOCERAS, VASCOCERAS, \ i; i) no i UNS He eee 281 : ane Le JPG) AVN) OW Merorcoceras, Herz. Pics l=44 Metoicoceras) swallow, (Shumand))s) Sse sys a eee ae ee eee eee eee eee 118 Figs. 1,2. The imperfect and crushed base of living chamber restored in fig. 2. 3,4. Right and left sutures of fig. 1, of same age, showing differences in number and outlines of auxiliaries. All natural size. Texas; Colorado epoch; Coll. Amer. Mus. Nat. Hist., New York. IRIGS sib =SemeMetorcocenasnguU LOST Kelby aut less aes tae ai ee ee eee 121 Figs. 5, 6. Natural size. 7, 8. Suture of right and left sides, respectively, as seen when looking at the specimen fig. 5, natural size. Texas; Coll. Amer. Mus. Nat. Hist., New York. Fics. 9-11. Metoicoceraus kanabense Hyatt @. Figs. 9, 10. Natural size. 11. Suture of left side of the second quarter of outer volution, x 23. The living chamber extended from the crack in the specimen, fig. 10, for the remaining one-half yolution, and was most probably nearly complete. Upper Kanab Valley, Utah; Colorado epoch; Coll. U. 8. Nat. Mus. larers, NOS, Jelaosien manana ISQYENIS Go ca sock aepeces5o sks eee sea snaosoadc so ssobasoseusouscosses 132 Fig. 12. Entire specimen, right side. 13. Same separated and center excavated, left side. 14. Front view of same, center one-half-restored. 15. Ventral view of fig. 12. 16. Suture at place marked by arrow in fig. 13, X 7, actual length 3 mm. 17. Dorsal suture, < 8, of second quarter of outer volution of fig. 12, one-half actual diameter 2 mm. 18. Suture of right side fourth quarter of outer volution of fig. 12, 3. All natural size except figs. 16, 17, and 18. Escragnolles, France; Barrémian; Coll. Mus. Comp. Zool., Cambridge. Gael O20 seEleunzranpnovun craves (C4 Or; (1 riya atts es 131 Fig. 19. Dorsal suture next to outer volution across the umbilicus and opposite termination of outer volution, < 9, one-half actual diameter 1.5 mm. Of same type, but more immature at the same age than in Heinzia matura. 20. Natural size. Locality and collection same. « No description of this species was found in the manuscript.—T. W.S8. 282 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XV Msi SS 8a oe is ie lin 2 @ 2 METOICOCERAS, HEINZIA. BLM SOV, | a Pi AW SOW IL Hernzia, KNEMICERAS. Fires. 1-3. Heinzia provincialis (d’Orbigny ) Figs. 1,2. Same as Pl. XV, fig. 20, broken to show young, X 3. 3. Lateral suture of the second quarter of outer volution of Pl. XV, fig. 20, x 4. Escragnolles, France; Barrémian; Coll. Mus. Comp. Zool., Cambridge. HIGSH4— SPAM CiCen aS) Sy TLCUNTUN ayi@ Tals 3 U1 Ln) eee ee = ee 146 Fig. 4. Natural size, showing length of living chamber, over one-fourth of a yolution. Coll. Mus. Comp. Zool., Cambridge. Lateral suture, < 23. Uncompressed typical fossil. Coll. Yale Mus. Part of suture of right side, 23, to contrast with next figure. Suture of left side, 3. Outlines perfectly preserved. Mount Lebanon, Syria; Cenomanian. Bigs: 9 -ONeAmemicenas) Compnessumsllny citi mes aru TIN) A SUZiC wart ee tepals a et 149 Locality, same as last; Coll. Mus. Comp. Zool., Cambridge. Fies. 11-14. Anemiceras compressum var. subcompressum Hyatt....-..------------------------- 150 Fig. 11. Specimen in collection of Columbia University. “Im ie) 12. Section showing transition from a rounded young to the flat and then con- cave venters of the succeeding stages, 2, from specimen in Mus. Comp. Zool., Cambridge. ; 13a. Enlarged view of center. 13b. Enlarged view of protoconch and first volution with first and second sutures. 14. One of Conrad’s specimens, natural size. Suture abraded. Coll. Yale Mus. j 5 Locality, same as last. Fies. 15-18. AKnemiceras compressum Hyatt ......------------- ne sisiSioeaisa Ses emcee uae cms cemmateees 149 Figs. 15,16. Type of species. Sutures abraded. : 17. Suture from line of involution to first lateral lobe at breadth of 54 mm. on left side. 18. Suture on right side to third lateral saddle at breadth of 63 mm. Locality, same as last. Fie. 19. Knemiceras compressum var. subcompressum Hyatt..........---------------+---------- 150 Ventral view, natural size, of specimen in collection of Columbia University. For sutures see fig. 11. Locality, same as last. 284 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL, XVI HEINZIA, KNEMICERAS ne Hii ean a ‘Sice Ealing Fis Ay ve a } TELA, SOW, ee 285 FE IG Ay AN 1B) DK WA IUIE, SuBPULCHELLIA, NICKLESIA, PULCHELLIA, KNEMICERAS, PROTENGONOCERAS. Bressil=5sysuonulchellvaxcastellanensis) bliy cits pae ee eee tee eae Figs. 1, 2. With shell complete on side of fig. 1. 3, 4. Same fossil, shell partly taken off. Right side of fig. 3 shows length of living chamber about one-half of last volution. 5. Lateral suture of fig. 3, X 3. All natural size except fig. 5. Castellanes, France; Neocomian; Coll. Mus. Comp. Zool., Cambridge. ley GA Nel Masel clonprensaonxe) (CPO oneII/)) see os casos aengs cose noooco senesced soeoeeseoouses Figs. 6, 7. Natural size. 8. Lateral suture, x 3. Locality and collection same as last. TG Se) O— lew BUlCelltancomipressiss ure cim (cls ©),\a) ee rasy) aes ee eee ee Figs. 9-11. Natural size. 12. Suture after Nicklés, Pal. sud-est de l’ Espagne, pl. 3, fig. 1b, 5. Locality and collection the same. Fires, 13-15) ‘Knemiceras attenuatum) (Elyaitt) sss. - esses see ee enters] seen see Aue Anant Figs. 13, 14. Natural size; shows living chamber nearly three-fourths of a volution. 15. Suture, X 2. Celendin, Peru; Cenomanian? HGS G—20 seroteng Onocendsy GO Om CE.0 Lim) ese ets ae Fig. 16. Shows living chamber to have one-half a volution in length. Shell is preserved on the living chamber. 17. Section shows the concave venter with lateral ridges at an early stage. 18. Ventral view of same. 19. Septum of same, 2. All natural size except the last, and all in Coll. Mus. Comp. Zool., Cambridge. 20. Specimen in Coll. Acad. Nat. Sci. Phila. Showing living chamber one-half of a volution, part of aperture on right side, and old-age folds. Arivechi, Sonora, Mexico. 139 142 151 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV_ PL. XVII SUBPULCHELLIA, NICKLESIA, PULCHELLIA, KNEMICERAS, PROTENGONOCERAS. cen St se Sy f % "i thers! Ae | pt ete yisisise ted) Abeer TPL NIN) SOVIET , Pe “ 287 PIG APD) SC WEIL: Kyemiceras, ENGONOCERAS, PROTENGONOCERAS. Page. WrGs: 123 Kenerucencisy aD bu ely atti eee sete ete ee ete ate ae Ic 152 Figs. 1, 2. Natural size. (After Gabb. ) 3. Lateral suture enlarged. (After Gabb.) Quebrada de Huari, Peru; Cenomanian? Fras. 4,5. Engonoceras belviderense (Cetin) conc couassecccosdssessso near scons a scqosssaassssoc 158 Figs. 4, 5. Lateral and ventral views. Belvidere, Kans.; Washita epoch; Coll. Cragin, Colorado College. Fies. 6-9. Protengonoceras planum Hyatt -.--.----------= +--+ = 2 =< 922252 156 Figs. 6, 7. Lateral and ventral views, X 2: 8. Lateral suture, X 2; the auxiliary saddles Nos. 8 to 10 should be a trifle broader. 9. Dorsal suture of the same age, X 2. Texas, my collection. PL. xvill MONOGRAPH XLIV U. S. GEOLOGICAL SURVEY KNEMICERAS, ENGONOCERAS, PROTENGONOCERAS, ABE CXGIXe MON XLIV-—03——19 PLATE XIX. ENGONOCERAS. F Page. Wines IG, Joe Mela (CHAIN) 5 55 soaks Cheacodes sso aaceseoesetses ee scesodeeassocs 159 Figs. 1,2. Type specimen from near Lindsborg, Kans., natural size. | 3. Lateral suture of same, slightly enlarged. 4,5. Specimen from McPherson County, Kans. Natural size, showing living chamber probably almost. complete along the umbilical shoulder and about one-half of a volution in length. The crease on the side of the venter of fig. 5 is an accident due to compression. Coll. U. 8. Nat. Mus. 6. Lateral suture of opposite or left side, < 23. The curvature is somewhat less than it is on the specimen. Kiowa shales; Comanche series, Lower Cretaceous; my collection. NG Sia 14s En GOnOCerasescrpenevrnecTian | Optic S100) ese arate alee see ghz Figs. 7,8. Natural size, living chamber one-half of a volution probably nearly com- plete on umbilical shoulder. The venter of inner volution of fig. 8 is decidedly concave. 9. Lateral suture, * 2. 10. Part of sutures of young fragment, « 2. This specimen is from near Deni- son, Tex. : x 11. Variety with broad ends to the costee and crowded peculiar sutures. 12. Lateral sutures, x 2. 13. Ventral view of cast, with similar costeeé. 14. Suture of same more like those of fig. 9. This is not due to difference of age. The last 5 and half of sixth saddle are dorsal. Four and one-half miles northeast of Gainesville, Tex., Denison; Washita epoch; Coll. U. 8. Geol. Survey. HiGs! ToS IemeE ng onacenasin clone Unie livia bt Capps yee ee eee 160 Fig. 15. Natural size, showing the late age at which the venter remains angulated, flat, and without tubercles. The rounded venter of the older stage is in ’ part due to abrasion. 16. Shows what was seen of the lateral sutures. 17. Dorsal suture of same age as oldest suture on fig. 16. Near Pottsboro, Tex.; Upper Comanche (Grayson), Washita epoch; Coll. U.S. _ Geol. Survey. : «The specimen here figured as H. retardum is described as E. uddeni on page 160.—T. W.S 290 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL, XIX ENGONOCERAS. ee o : 2 n é i * 2 PA Ko | 291 ; Se | : PAT XOX: EXNGONOCERAS. Figs: 1-5: Engonoceras senpentinund ((Cragin))= 252 == 2 a ene in 162 Fig. 1. Suture showingall of one side, part of the other and dorsal suture, < 2. 2,3, 4. Three views of one of Cragin’s figured types. 5. Suture of same, X 2. Near Denison; Washita epoch; Coll. Cragin, Colorado College. Fias. 6-13. Engonoceras pierdenale (von Buch) ..-.-------------------- Satis BU a I eda 165 Figs. 6, 7. Specimen from Towash, Tex.; Coll. Mus. Comp. Zool., Cambridge. 8. Suture of same, * 2. 9, 10. Specimen from near Cerrogordo, Ark.; Coll. U. S. Nat. Mus., No. 22643. 11. Suture of same, natural size. 12. Specimen from Seven Knobs, 5 miles southeast of Glenrose, Tex. 13. Suture of same, 2. Fredericksburg group, Comanche series. 292 U, S, GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XX ENGONOCERAS. TE ID A 18) OO ENGONOCERAS. Fic. 1. Engonoceras pierdenale var. commune Hyatt..--.----..---- SSPE NE ace RNS pli hes Sa 165 Fig. 1. Suture, x 2. Bell County, Tex.; Fredericksburg group, Comanche series. Coll. U. 8. Nat. Mus., No. 8301. ENG S29 2—G'a eH G OMLOCE AS) StUD] ECLLUIT tcl uy el Leyes ea 168 Figs. 2,3. A specimen from Gabriel, Williamson County, Tex.; Coll. Mus. Comp. Zool., Cambridge. 4. Portion of septum of same specimen—the middle one of the three indis- tinetly shown in fig. 2, & 2. 5. Last septum of same specimen, 2. 6. Septum of a smaller specimen from same locality, x 2. Washita(?) group, Comanche series. 294 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXI ENGONOCERAS. Lous SOs, 295 BevACd RSs SXOxe Iie ENGONOCERAS. Page. iGsil—on eb ngonocenasistojectunn Maly alien ayaa eater eee orale eee ee alee eeite 168 Fig. 1. Specimen from Duck Creek beds, near Denison, Tex.; Coll. U. 8. Geol. Surv. 2. Suture of same, very slightly abraded, X 2. 3. Specimen from Grayson, Tex.; Coll. D. S. Martin. 4. Suture of same, X 2. 5. Suture of specimen from Tarrant County, Tex.; Coll. Cragin, Colorado \ College. ; Washita (?) group, Comanche series. Eres G—1O eb ngonacenasiquOUOSUmupbliy aut eaten eel ete ata atal ater 171 Fig. 6. 296 “I 10. Lateral view of a small specimen from Goodland limestone, 15 miles west of Denison; Coll. U. 8. Geol. Surv. . Ventral view of same, partly restored. . Septum of same, 2. . Fragment doubtfully referred to the species, from Bell County, Tex.: Coll. U.S. Nat. Mus., No. 8301a, x 2. Septum of same, partly restored, x 2. Fredericksburg group, Comanche series. U. S, GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXII ENGONOCERAS. ate ( ene at ay tines ats oe tee Note ei AES aertiCS ya ¢ IE Ibe ah, SX OIL. Verb Dy OC INILIE. ENGONOCERAS. 7 Page. Ie. UES. JING OATON GPOLOSIIO ISDN s cao salaaassosconssoodno snes ba Sedecosseecs doogseobeoss 171 Figs. 1, 2. Specimen from Cook County, Tex.; my collection. 3. Suture of same, * 2. 4, 5. A fragment from the Goodland limestone, 15 miles southwest of Gaines- ville, Tex. 6. Suture of same, x 2. Fredericksburg group, Comanche series. RTGS 9s EG ONLOGERGS) SLOLLCT tip I 0 ETI page at eset neoebe 175 Figs. 7, 8. Young specimen in Cragin Collection, Colorado College. ; 9. Suture of same, X 2. Fredericksburg group [?], Comanche series. 298 MONOGRAPH XLIV PL, XXIII U. S, GEOLOGICAL SURVEY ENGONOCERAS. 5 ve aie hen er AH XOGEVE 299 IP 1b AA I TB XO IW. EXNNGONOCERAS. Ines WES, JIAGOMOCTRAS SHOUATE VION WING os Sane Sa osesSecee coo seesocoedcee=bosccsoeoosasSeecoose 175 Figs. 1, 2. Specimen in my collection, partly restored. 3, 4. Specimen in Coll. Hill, U. 8. Geol. Surv. [‘‘ Hill 4a.’’] (?) 5. Suture of same, X 2. This is somewhat worn down. Fredericksburg group [?], Comanche series. WIGS: 6—GueENGONOcenas {COM pliCodum Ly aL bese eee eee ee aiate eee eee eae sete salar 175 Figs. 6, 7. Type specimen from near Austin, Tex. Coll. Hill, U. 8. Geol. Surv. 8. Suture of same, X 2. Comanche Peak limestone of Fredericksburg group, Comanche series. 300 MONOGRAPH XLIV PL. XXIV U. S. GEOLOGICAL SURVEY ENGONOCERAS, POeL ATH soa | IPO AN Tay GOO: NEoLositEs, METENGONOCERAS. Page. TGS 4s Neolobrtesl chop atin belsy cuts stearate te eet ee 178 Fics. 1, 2. Copies of Choffat’s figures 3a, 3b, published as NV. wibrayeanus. ; 3, 4. Suture of probably the same species (after Choffat). Cenomanian; Portugal. Fics. 5-9. Metengonoceras inscriptum Hyatt...--...--.----------------------+--------+--------- 180 Fie. 5. Section of fragmentary specimen from west of Walnut Springs, Texas: Coll. Cragin, Colorado College. 6. Suture of same, enlarged. . Suture of asmall fragmentary specimen from 12 miles northwest of Decatur, Tex.; Coll. U. S. Geol. Surv. : . Suture of fragment from 15 miles west of Denison, Tex.; Coll. U. 8. Geol. Surv. 9. Ventral view, partly restored, of specimen from 12 miles northeast of Decatur, Tex. For other figures see Pl. XX VI. : Fredericksburg group, Comanche series. PL. XXV MONOGRAPH XLIV U. S. GEOLOGICAL SURVEY NEOLOBITES, METENGONOCERAS. LAIN x - i a 12 Ty AI JD) CO WIL METENGONOCERAS. Page Fies. 1-4. Metengonoceras inscriptum Hyatt..........-..------------.------------- Sepa NE aieials 180 Fig. 1. Enlarged suture of specimen represented by figs. 2 and 3, and by Pl. XXV, fig. 9. 2, 3. Specimen from 12 miles northeast of Decatur, Tex. 4. Suture of large fragment from 9 miles from Austin, on Beecaves road. Coll. U.S. Geol. Surv. [This drawing was labeled M. ambiguwm, but the specimen is described under M. inscriptum.—T. W. S8.] Fredericksburg group, Comanche series. Hiess 5-7/1, Metengonocerasiambiquium: kuyatbas se see nese sees ee eee eae eS SAeCRO 183 Fig. 5. Side view of type. 6, 7. Suture of same specimen, X 2. Nine miles from Austin, on Beecaves road; Fredericksburg group, Comanche < Peak limestone, Comanche series. Coll. U. S. Geol. Sury. Iie Bh WAC OROGAOS COO ISIE caocasac soodcosuanbacese nase s630556 sesansaoscascess cae 184 Side view of fragmentary type specimen. Elm Fork, Dallas County, Tex.; probably Eagle Ford shales, Upper Cretaceous. Coll. Mus. Comp. Zool., Cambridge. 304 PL. XXVI MONOGRAPH XLIV U. S. GEOLOGICAL SURVEY METENGONOCERAS. i ‘ i i 13 AE is 4 , 4 PLATE XXVIL Be ie “MON xr1v—03—20 rae ae 805 IPE AMD 1B SO OW UIE MErENGONOCERAS, PLACENTICERAS. Page. Figs. 1-2. Metengonoceras acutum Hyatt.......-------------------+- 222207 -e rrr recess cscs: 184 Fig. 1. Ventral view of type specimen. 2. Septum of same, * 2. Elm Fork, Dallas County, Tex., probably Eagle Ford shales, Upper Cretaceous. Coll. Mus. Comp. Zool., Cambridge. Fis. 3-14. Metengonoceras dumbli (Cragin) ..---.-------------------+-+2+2-2- rrr 2 2c rrrrrrse 185 Figs. 3,4. Lateral and ventral views of specimen described. 5. Section of same. 6. Inner whorls of fig. 5, enlarged. 7. Center of same, still more enlarged, showing antisiphonal lobe, the inner- most whorls having dropped out. 8. Section of whorl in neanic stage, < 10. §. Adult lateral suture, X 23. 10. Last lateral suture, < 23. 11. Dorsal suture continuous with fig. 9, enlarged. 12. Dorsal suture one-fourth volution older than fig. 11, enlarged. 13. Lateral and part of dorsal suture of neanic stage, x 18. 14. Dorsal suture of somewhat later substage than fig. 13, enlarged. Four miles east of Whitesboro, Tex.; Eagle Ford shales, Upper Cretaceous; Coll. U.S. Geol. Surv. ; i Fras. 15-17. Placenticeras syrtale (Morton) ....----------------+-----------+-+++-+------------ 205 Fig. 15. Suture of the type in Coll. Acad. Nat. Sci. Phila. 16. Lateral suture of var. halei, Coll. Bost. Soc. Nat. Hist., No. 85 17. Dorsal suture of older part of same volution as fig. 16. Greene County, Ala.; Eutaw beds (2), Upper Cretaceous. “I on PL. XXVII MONOGRAPH XLIV U. S, GEOLOGICAL SURVEY PLACENTICERAS. METENGONOCERAS By Ses ee oy a i " Ee ae ee TELA, SOC JO IE 1B; SOR TE IL PLACENTICERAS SYRTALE (Morton). (Page 205. ) Fras. 1, 2. Two views of the type, Coll. Acad. Nat. Sci. Phila. (For suture, see Pl. XX VII, fig. 15.) 3, 4. Type of yar. halei, Bost. Soe. Nat. Hist., No. 8577. (For suture, see Pl. XX VII, figs. 16 and 17.) 5, 6. Another specimen of var. halei, same collection. Eutaw beds(?), Upper Cretaceous, Greene County, Ala. 308 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXVIIi *PLACENTICERAS. Shy a | i At cap. JE VO IN Tay, DCO MO PLACENTICERAS GUADALUP® (Roemer). (Page 197.) Fig. 1. Lateral view of a large specimen. Aperture view of same considerably restored. oo to . Section of same. 4. Enlarged section of inner whorls of same. Near Fort Worth, Tex.; Taylor beds (?); Upper Cretaceous; my collection. 310 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XxIx PLACENTICERAS. ae an ‘ i ea anat ee rene FAME XOXO: PLACENTICERAS SANCARLOSENSE Hyatt. (Page 200. ) Fig. 1. Side view of an average-sized specimen 2. Aperture view of same. 3. Suture of same, 2. San Carlos, Presidio County, Tex.; San Carlos beds; Upper Cretaceous; Coll. U. 8. Geol. Surv. 312 U. &. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXX PLACENTICERAS. ile 7 ee 4 ce ‘ 7 % t 4 PLATE XXX1 2 ‘ Y 3 , a = 4 " r Saye JEG, ANID 1B) OO OC IE.. PLACENTICERAS. IGS lee oa eLACeNLICERcesISCmCamLOSCTSCmllny ab Uj eee ee eee eee 200 Fic. 1. Section of a small specimen—‘‘passage form between this species and guadalupee.’” 2. Side view of same. San Carlos, Presidio County, Tex.; San Carlos beds, Upper Cretaceous; Coll.U. 8. Geol. Sury. Wier G5, Jee NOGON TgBoaMaD, IBN 6556 ose-sceosochoossoseoosoeucsseassasesssecesassas 203 Fig. 3. Side view of the type specimen. 4. Section of same. 5. Aperture view of same. Near Presidio Del Norte, Chihuahua, Mexico; San Carlos beds, Upper Cretaceous; Coll. Columbia University, No. 10073G. 314 b. S. GEOLOGICAL SURVEY PL. XXxI MONOGRAPH XLIV PLACENTICERAS 4 Rive PM oor, ' ‘ , 7 + ty ~ 7 eee Sine 5 Sioa IP by Ae AN DOI IE, PLACENTICERAS SANCARLOSENSE yar. PSEUDOSYRTALE Hyatt. (Page 200. ) Side view of type of variety (see Pl. XX XIII, fig. 1). Near Fort Worth, Tex.; Taylor beds (?), Upper Cretaceous; my collection. 316 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXxil PLACENTICERAS Te 1b ACAD 19) DON ITIL, PLACENTICERAS. Page. Hie. 1; Placenticeras sancarlosense var. seudosyriale Eiyatt 222222222222 222 eee eee eee 200 Fig. 1. Aperture view of specimen figured on Pl]. XX NIT. ies: 2-44 -Rlacenticenas plant Ely alitesaee Seen ae eer eee ee See eee eee eee eee 202 Fig. 2. Aperture view of medium-sized specimen partly restored. 3. Side view of same. 4. Peripheral view of another specimen showing less development of nodes. (See Pl. XXXIV, fig. 1.) San Carlos, Presidio County, Tex.; San Carlos beds, Upper Cretaceous; Coll. U. 8. Geol. Survey. PL. XXxiIlII MONOGRAPH XLIV U. S. GEOLOGICAL SURVEY PLACENTICERAS, Fy BNSrins 12 GAN IB OS OO II PLACENTICERAS PLANUM Hyatt. (Page 202. ) Fie. 1. Side view of the small specimen represented by Pl. XX XIII, fig. 4. 2, 3. Aperture and side views of a larger specimen. San Carlos, Presidio County, Tex.; San Carlos beds, Upper Cretaceous; Coll. U. S. Geol. Survey. 320 PL. XXXIV MONOGRAPH XLIV U. S. GEOLOGICAL SURVEY ERAS. PLACENTIC > ea 321 Ty AGAIN Ne NGINGRV PLACENTICERAS INTERCALARE Meek. (Page 207.) Fras. 1, 2. Side and aperture views of medium specimen (see Pl. XXXVI, fig. 1). [Black Hills?], Fort Pierre, Upper Cretaceous; Coll. Yale University No. 1863. 322 U. s. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXxxV PLACENTICERAS. a Ath xeoag Te AAD I, OK ONE IES PLACENTICERAS INTERCALARE Meek. (Page 207.) Fic. 1. Opposite side of specimen figured on Pl, XXXY. 2, 3. Side and aperture views of small specimen, No. 2104b. 4. Suture of same, * 2. ! 5. Parts of two septa of Geological Survey specimen from Harper, Wyo., represented by Pl XOXGXVIL, figs: 1; 2 Fort Pierre, Upper Cretaceous, Coll. Yale University (except fig. 5). 324 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXXVI PLACENTICERAS. ae ‘i oe : ‘i ; i hy j eeATE OOO an « 1 na Pen 24 . ' a gid ‘ PG TAS aeRO XOX alia: PLACENTICERAS INTERCALARE Meek. (Page 207.) Fics. 1, 2. Fragmentary small specimen from near Harper, Laramie Plains, Wyo.; Coll. U. S. Geol. Survey. (See Pl. XXXVI, fig. 5.) : oF Section of specimen ‘‘approximating to some varieties of P. stantoni,’’ from Ponil Canyon, New Mex.; Coll. U. 8. Nat. Mus., No. 9735. 4. Side view of same specimen. (For suture, see Pl. XX XVIII, fig. 1.) Montana group, Upper Cretaceous. 326 U. 8. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXXVI PLACENTICERAS. were Ten poor LEDER 18) OOO NC IOTE IC PLACENTICERAS. u Page Hires 1s sPlacenticenasmiencalamee Nice kes ae ee ee Sepia MSE es Sete 207 Suture of specimen from near Harper, Wyo. (SeePl. XX XVII.) Montana group, Upper Cretaceous. EGS) LACE UIGERMs unten COLO nV AMes |COSHCULUNT OM Kalay/ UU Ue et terete ean et 207 Side view of type of variety, my collection, purchased from Ward. Probably from Black Hills, 8. Dak. Montana group, Upper Cretaceous. 328 PL. XXXVIIL MONOGRAPH XLIV U.S. GEOLOGICAL SURVEY PLACENTICERAS. a. | PIL, LOOKING Je yy OX OCI PLACENTICERAS. Page. GSMs) 2m LCentCencsKimten Calan ciyan aCOSt ELI e lelay (et tees a 207 Figs. 1, 2. Aperture yiew and suture of specimen represented by Pl. XX XVIII, fig. 2: . RIGS 3—OmePlacenpicenas ola certo (CD e kiya) Nessa eset sere ar ae 211 Fig. 3. Fragment of a small specimen from Chesapeake and Delaware Canal, Coll. Acad. Nat. Sci. Phila. +. Suture of same, 2. 5. Side view of small specimen from Lenola, N. J. 6, Sutures from smaller end of volution represented by fig. 5 enlarged four diameters (see Pl. XL, figs. 1, 2). Matawan (?) formation, Upper Cretaceous. . 330 U. §. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XXXIX PLACENTICERAS., JP 1 AN IPI XS Wye PLACENTICERAS. Fias. 1, 2. Placenticeras placenta (Dekay ) Fig. 1. Peripheral view of specimen represented by Pl. XXXINX, fig. 5. 2. Side view of same, enlarged nearly two diameters. Figs. 3-7. Placenticeras stanton var. bolli Hyatt Figs. 3,4. Aperture and side views of the small specimen from Tarrant County, Tex., in the Martin collection, Rutgers Female Institute, described by Meek as P. intercalare. 5. Suture of same, * 2. for) . Fragmentary specimen from Horton’s mill, Dallas County, Tex.; Coll. Mus. Comp. Zool., Cambridge. 7. Lateral and internal suture of same, xX 2. (See Pl. XLI.) Taylor beds (?), Upper Cretaceous. 332 PL. XL MONOGRAPH XLIV U. S. GEOLOGICAL SURVEY PLACENTICERAS. PL Ape) aca ACAD ii Xee Ar: PLACENTICERAS STANTONI var. BOLLI Hyatt. (Page 214.) Fic. 1. Sectional view of specimen represented by Pl. XL, figs. 6 and 7. Restored section of same. Living chamber of a larger specimen. Last suture of same specimen. 6,7. Living chamber of another specimen. Horton’s mill, Dallas County, Tex.; Taylor beds (?), Upper Cretaceous; Coll. Mus.. Comp. Zool., wo Ex ES) I Cambridge. Bist: PL. XLI MONOGRAPH XLIV U. S. GEOLOGICAL SURVEY PLACENTICERAS, ea Ri von ete i 4 Re i p " eee ui ae \ el Ae chm JE? Ly 8 I Sie OC TL TE IE PLACENTICERAS STANTONI var. BOLLI Hyatt. (Page 214.) Fic. 1. Suture of young specimen enlarged about 23 diameters. 3 gS} g 2 2. Part of living chamber and last septa of a large specimen. Horton’s mill, Dallas County, Tex.; Taylor beds (?), Upper Cretaceous; Coll. Mus. Comp. Zool., Cambridge. Gy dab 2 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XLII PLACENTICERAS. Ok ae pan Seay he 7 sy. is ’ : « J . ‘ i ; - . ’ n c ; . i 5 hee! “ . ‘ et, Ay xs IE 2 53 a no ERY : ‘ u ; ‘i P ¢ af fi = DE AP OIL EET PLACENTICERAS. : Page. Fies. 1, 2. Placenticeras stantoni var. bolt Hyatt....--..----------------------+-------------- 214 Fig. 1. Side view of small costate specimen. 2. Suture of same, > 2. ; Horton’s mill, Dallas County, Tex.; Taylor beds (?), Upper Cretaceous; Coll. Mus. Comp. Zool., Cambridge. ; Figs. 3-11. Placenticeras pseudoplacenta Hyatt.......-..--.---------------------------------- 216 Fig. 3. Side view of small fragmentary specimen. 4. Sectional view of same. 5. Center of same enlarged. 6. Ventral view of first whorls of same specimen much enlarged. 7, 8. Inner whorls of another specimen, natural size. , 10. Lateral sutures of last whorl of same as indicated on fig. 7. Upper Kanab Valley, Utah; Colorado group; Upper Cretaceous; Coll. U. 8. Nat. Mus., No. 22344. 11. Parts of internal sutures of ephebic stage when dorsoventral diameter of ? yolution measures 49 mm. Muddy Creek, Huerfano County, Colo.; Fort Benton formation; Upper Cre- taceous; Coll. U. 8. Nat. Mus., No. 22199. U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XLIII PLACENTICERAS. Se re Ys ¥ a i= ( ; i Pe ACUH) Saleing se 7 ’ Urs F 4 ' ‘ . vy ae : } j ay i } ty nf iN Wi , } v 4 ; (a Ne : : i Th te Je AIT Wd) OIG EW PLACENTICERAS PSEUDOPLACENTA Hyatt. (Page 216. ) Fries. 1, 2, 3. Three views of living chamber of fragmentary specimen. Bad Lands, near Black Hills; Upper Cretaceous, 8. Dak.; my collection. 340 U. S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XLIV PLACENTICERAS, 4 : PLATE Xv PA ASU Ne TEE PLACENTICERAS. Fies. 1, 2. Placenticeras pseudoplacenta var. occidentale Je AINE area a aaa Ne ae MEG eae nes 217 Fig. 1. A specimen from the Upper Missouri River; Coll. Columbia University, No. 10622G. 2. Suture of a young specimen from Horton’s mill, Dallas County, Tex.; Coll. Mus. Comp. Zool., Cambridge. IEE, GalG, JAaemaiearas cai hOtels ISVEIN, soo eeacocecd es anoneses aoc cosaenes seunnoseneaees Here 221 Fig 3. Side view of small fragmentary specimen from Clifford, Nebr., in Coll. Mus. Comp. Zool., Cambridge, enlarged. Section of same showing venter of earliest whorls, >< 3. Ces Center of same, about 63 diameters. First two sutures and beginning of siphuncle of same specimen, much for) enlarged. Beginning of siphuncle of same after etching with acid, still further =I enlarged. 8-10. Early stages obtained by breaking down a larger specimen from the Black Hills, South Dakota, in my collection; enlarged about 5 diameters. 11-14. Complete sutures from dorsum to venter of same stages as figs. 8, 9, 10. Fig. 11 is earliest suture visible on fig 9; fig. 12 is on last quarter of same whorl; fig. 13 is last suture on fig. 10, and fig. 14 is nearly a volution earlier. 15. Dorsal (internal) sutures at diameter of 15 mm. Same at diameter of 40 mm. The last two figures may not be from same specimen as figs. 8-14. Montana group, Upper Cretaceous. 342 MONOGRAPH XLIV PL. XLV U. S. GEOLOGICAL SURVEY PLACENTICERAS. mn ve pare ie Palit PLATE XLVI. i ran i 4 » TEI AI CIN IL PLACENTICERAS WHITFIELDI Hyatt. (Page 221.) Fies. 1, 2. Two views of a large specimen, ;°; actual diameter. Black Hilis, South Dakota; Montana formation, Upper Cretaceous; Coll. Bost. Soc. Nat Hist., No. 11124. : 344 1A1X “Id AITX HdVHSONOW A3AYNS 1V9IN01039 "Ss "Nn MONOGRAPH XLIV PL, XLVI U. 5, GEOLOGICAL SURVEY PLACENTICERAS. oe Sy 6 ri We) E; & x Ere Og ate we JIG AN AD) DOIG. IE AL: PLACENTICERAS. BIG SH 14 PPP lO CEntiGenc sri IUULfLeL Cum Eelay; elit ps sea a a Figs. 1, 2. Two views of the inner whorls of a small specimen from the Upper Missouri; Coll. U. S. Nat. Mus., No. 18936. 3. Fragment showing peculiar sculpture of the inner shell layers, probably from Black Hills, South Dakota; my collection. 4. Another specimen showing similar sculpture from same collection and region. ‘ Montana group, Upper Cretaceous. Eig. 5. Placenticeras wviutpielan- van: tubenculatum Elyattss 2222252255252 2222222 eee Fig. 5. Side view of the type of the variety. Montana group, Upper Cretaceous; Black Hills, South Dakota; my collection. TGS G— Ose LeLCLGCTALUGEN USNS To ULL I Te CUD) Ley ct Ue = see a a nS Figs. 6, 7. Two views of the fragment on which the species is based. 8. Part of weathered suture of same. Ripley formation (?), Upper Cretaceous; Mississippi (?); Coll. Acad. Nat. Sei. Phila. [Norr.—Professor Hyatt indicated that the drawings for figs. 6 and 7 were unsatisfactory to him, but the specimen is too imperfect to serve as the basis for a restoration ]. 346 U.-S. GEOLOGICAL SURVEY MONOGRAPH XLIV PL. XLVII PLACENTICERAS INDEX. [Names in italic are synonyms; in italic denote illustrations. ] Page. JX DMU NOCENDIS coscosac conn sdoéeeanodesboodessoceduoacoEs 27 spiniferum Whiteaves...--........-.....-..------- 110 - Acceleration of development..............-.-- 19-23, 189-190 ACOMIPSOCeraSHHY Att). =- 5-2-2 = omen on 105, note; 111-112 bochumense (Schliiter),-...-....-.--------.---. 111-112 essendense (Schliiter) .............--.------------- 112 Menem elie (SHANE) saeeeeee sess eeae eects ae 112 PACONLECELTAS HELM Abbe epee saan eeeeeereinee ale £8, 100, 101, note muse, (GON woh) o> o-caonspusceon encase 90, 99, 100, 276 JNEERSICORIB) co gsce sesso nosenda cas ssoneeaoases ssedescuscT 24 striaries. -. 24 Amailtheus ebrayi de Loriol..........------.------------ 234 Am onitesasessseee see eee Bees 2 Sosa vate eet 43 LICE TILOLUS) GeD Desist aisles sial= cieielnielaiael= =a) 152 OCULAR UIE V SCLIN Beas eee ee eee oe ase = 191, 192, 244 BEMGenensis\ Grea eee ale iain a elnrelelereil == 158 GLO SOUU SHO CIN CT eetese state tee asta ae acini le nl 243, 244 YMapoanNS (CANDO e — soconaesoene Bp oS SEES OOOH EDOOBESSES 30 QHIGHA USEMSICM 5 -s9oscacedsssenuoscsneopaopnecasod 133 COINS CUOMO SINGS cod aosenssonsSeaGOS ES SeeRSbnoenes 143 clypeiformis V Orbigny....-.--.-------------------- 85 compressissimus @'Orbigny...-.--.----------------- 142 CONCHLOVUSI STON CZ Alem aaa ee eae ee ieee 107 COULOTUGLOLDIS Tye meee nena see laelnelnn == lo cle 11d GRETA BIOIIOAIN 5 a= sa cesonSanadnasasusesoosSstos 107 CUI US COU CZ Kage eee eee ee eee siete taeieiae= aa 107 CAETHINS VEN Mis cae soaocsmenBeocosobosTEcuposs osc alt) didayanus @ Orbigny .......---.-------- oowet 181, 136, 138 (lis nah GUO NAN Fahy 4a ee Sesc cane osoeoaesepoe cose seeEoe 141 domeykanus Bayle and Coquand..-...--.----------. 115 dumasianus d’Orbigny..---.----------------++-+--- 139 CMO NUD LOLS] oi BID Cote metale eins areola alata lalla oleate ales elal 107 ewaldi yon Buch ---- 46,48 galeatus d’Orbigny..--..-----------.---------- 135, 136, 142 GEVILUUUUS CU. OLDIE Tyee ela alm =m == me ala mle =Ia\= = 35, 37, 38 DuUlchelilitormi Swbty altieeee eee eee eee eee eee 131, 132 Classification, tabular statement of...........--------- 15-18 Ehyubl JEW CNiTKEeecsoemooEmoccheouencosobocnecheasocus 180 Coilopoceras Hyatt.........--.- BSUS IS 7—89) Olen OO yl Olli em tems eel ein 77 Cl ee eee selene eee eee eee err 117, 128-136 Colle niEby sities eeetmte eee eer 91-94) 95,272,274 | Hemitissotia, Peron. 5. 22222. esse n= ees eee 35, 36, 38 STOSSOUVACIENy aiteee semeeeeeeeee eee ae eee snes 100, 271 batnensis;Perony coun eae ee eee eee 39 novimexicanum Hyatt......-..-.--- 91-93, 94-96, 97, 272 Cazini Peron...........- 39 requienianum (d’Orbigny) .-.--.----- 99 ceadouroensis Choffat - - 40 springeri Hyatt..........-. --- 96-99, 276 djelfensis (Peron)...-- - 40,54 Collopoceratidee=2--45----------- <== = 24, 88-100; 101, note MOrreniy (COqUManG) Rese eee eee eee eee 39, 40 Cope, Edward D., on acceleration and retardation in PERCIPUR) Foo see Se oe ees RN Sen ae teenie terse 41 developmentitpees-sseeee ease 20-23, 189-190 tissotieformis Peron ...--- PARSER NS oe ae ere ea 40 COLOMILeS senate ee el serene LOLS 30s olem | MELeterotlssomaEb CrOnse eee eee eee eae eee 55 COLODALOIG ES alee nee eee eeieeee eee eee 130, note meocersibitessPerOn eas ses eee eee ee eee ee eee eee 55-56 Cosmoceratid yeeereee sees eset eee eee eae aa 101=105% ECO DIIteS Pesan eeeee eee seat tee ane see 101; 130, note; 193 C@retacie suselotitenmgeren essen er aaa ee aera 11 Op LibifO TM SEeee seer 131, note IDYEGTMOYCSMIS oS Sasuosodeosescss ecco sobs sdosssesso5 101, note splendens........- 192, 193 25 | Hoplitide ....-.- 131, note; 187, 192 Development, acceleration and arrestation of. 19-23,189-190 | Horizons, table of. 18 Miadochoceraswklyatieasassseoceee loess eee 105,106,107 | Hyperlioceras discoidum .- 2 19 nodosocostatum . - ---- 106,107 Sli ovehKefonKa lot Coen Soncoaddocteasdsousdsoneoeassees 19 Diplacmoceras Hyatt... 189} 192, 249-943") Eiystatoceratid seo... ss. eens we ale eos aan ante = = 24, 26, 27 bidorsatumiGRoemen)eaeeeeseee= eens eeceeeree ea 24/3 al Palo cl OCeraSHN OUI Pye reer alert tetinaia eer eieeaetatate 56 Cana lie ml apie Ely atitemeeeeasaeeaeietieeeeeer te 243-2944 acutodorsatum (Noetling)........---:-.----------- 57 Douyilleiceras Grossouvre...-.--------- 105-107, 108-109, 113 baluchistanense Noetling......-..--.------------- 56-57 mamumillare (d’Orbigny)-.--.---.-.------------- 109,113 | Knemiceras BOohm..........--.--------------- 26, 30, 145, 192 @udoytenohiAl BNNs He cocin oo ssaeenoueeaorcnee -oosesuces 110 attenuatum (Hyatt) --, 38, 151, 152, 286 Spinifervim (VIL Ves) )\ essen eee eee eee 110 compressum Hyatt.......-. .-- 149-150, 152, 284 Echinoids, parallelism in local development of --. 195 var. subcompressum Hyatt - 149, 150-151, 284 Engonoceras Neumayn------.-----:-------- 22-2. = 20; 21, 58, MOUS poe esses pescosssca=cosanessessonls 152, 288 145, 147, 153, 156, 157-158, 178-180, 182, 196, 198, 242 syriacum (yon Buch) -....-.--..-----.- 146-149, 150, 284 belviderense (Cragin) --.- 158-159, 288 LUA EtT (COMM) 55 Goose asseboescosscosces SHaeicAacan 152 complicatum Hyatt -..-- . 175-17'7,300 || Knemiceratidee-. ------ nn 144-152 emarginatum (Cragin)...........-.----..-.- 159,160,177 | Lenticeras Gerhardt......--..------.-------------- 84-85, 103 (aldo OWA ose oooocouo neon asoocsSoEpSoSsonSeoeeS 153 Phos Hb Ae RUE Read SN er one er he Peas eaueae 84-85 gibbosum Hyatt..........-.-.-..-...-.- 171-175, 296, 298 | Lenticeratidee .....-..---- ae 24 ANSCriptuUMsscegss atc eiee nese ee eee eee aes 183 | Leptocampyli-....----..-- so 25 MCQETNAUSP BO DM seem ttelsteelalelsm ieee eee ee eee eae 165 | Libyeoceras Hyatt -- 56,57 pierdenale (von Buch) ...-- 157, 158, 165, 167, 170, 175, 292 ismaele (Zittel) - 58 Var. commune) Hyatt <2 2-22 sane nn 165-168, 29, | Lophobolites Hyatt.-.........----------------+--- 41,137, 144 retardum Hyatt. - -- 160, note; 290 Cloynnceenbou (ONMONAS) 2558 So osngcocoss se eseeeseeseosscs 144 moonnerar (COMPSbA)) 4 coegansadosconeoSnoncasoSeSs 172,177 | Mammitida -.-.-----------..----.------ 24,27; 101, note; 109 serpentinum (Cragin) . 162-164, 167,171, 290,292 | Mammitide ........--.-..-------2--------------+------- 24) StolleyaieB Ohim Seem cleo ae salle eee 157, 175, 298, 300 | Mantelliceras Hyatt.-.........-.---------------- 110, 111, 113 subjectum Hyatt............ 58, 161, 164, 168-171, 294, 296 ecouloni (diOrbigmy,)---------- ===. == 2 114 midcdenii (Crap) lessees 154, 158, 159-161, 175, 290 domeykanum (Bayle and Coquand) - 115 Engonoceratide-.........-.../..---- 144, 145, 153-187, 193, 248 indianense Hyatt-....-.-.-.------------------.--.- 115 TITAN TO CELSS ree tsa es oe aro ce oes ogee Ste 102 mantelli (Sowerby) - 111,113, 114 Eulophoceras Hyatt ..... -- 83-85, 100 picteti Hyatt lit natalense Hyatt -.--- -.. 86-87, 274 ANAS (SiON) soso seoccooacesssensocsosscasssec 115 Eulophoceratide -.-. ... 24, 83-87 vicinale (Stoliczka) ...-.....-..------------------- 115 Hamiliesnelassitied slistiotes sae seen eee eee 15-18 | Mamtelliceratida -22-5-- 5.222232 === nnn 105 Gabbioceras batesi (Gabb) - Mantellicenraiid 2 seeeeeee eases aeeeeeeeereesee a 105-116, 141 Generasclassifiedulist ofseceeases- seeeeseeeeee eee Metacanthoplites rhotomagensis (Defrance).....----- 107 INDEX. 349 Page. Page. Metasigaloceras Hyatt.......-..-....-..-..-.---------- 106s Pediocersas\ Gerhardt: ose. ee oes on en eee eee 105, 108 rusticum (Sowerby) ee LOGn| CACTICSCNSISMese sent = aaa ene sens tee eee 107 Metatissotia Hyatt... 3... 022-2. 43, 45, 50,55 | cundinamarce Gerhardt ........------------------ 107 BUTESSONSIS) (RELON) sect ae se cena ciate micas eae 49 | Ubaquensisi--- =-----.-- es) alt] nya in (VODUBUCH)) (fs o-oo emia wm wom ancien CUP BY) || Geto Ko(cer nMOS Se eee basen oecsoneac sas 105 fourneli (Bayle) -....-.----.- 45248) |) Peroniceratidusmeessee esse esse eens eee eee re 24,27 haplophylla (Redtenbacher) ........--.--.-------- 48 | Phricodoceras 105 Modosarkbyattee----------- -- 46,47, 48 | Phy TOCsUM p yliseee eee seem eerie a enter ett 25 MOU (EMHIOMICLE) — econ ieee oe 45,46-47,48 | Phylloceras slizewiczi (Fallot) AOR SPhyMoceratidce secre em setae ae see Metengonoceras Hyatt.....---.---- 153-155, 158,170, 179-180 | Placenticeras Meek ACUTUNOLER SiG p acne ee neces sss cee 184-185, 187, 304, 306 22, 94, 140, 145, 153, 155, 178, 185, 188-196, 243, 244 Gmmnjaytapneben IBA R A oon oe oeeehoeeEeaBecoonec 183-184, 304 californicum 192, note dumbli (Cragin) -.. -- 180, 185-187, 306 GLASSRPUDISEL ya pee ie ee ee etcetera eter 241 inscriptum Hyatt .....---.----- 180-183, 184, 185, 302, 304 Cepressumybly athe. seater et Metoicoceras Hyatt ....-...---- 101, 110, 113, 116-117, 129, 154 ebraya (es GOri0l) poser see ena PAC CELELA HUMNGE yA uty etme eer le nla a mtaiata =i lateata = 127-128, 280 fallax Castillo and Aguilera gibbosumibtyatt.--.--------------- 121-122, 282 fritschi Grossouvre ..-------- ean a en SCpely abe seem ania one elalte iin a 282 grossouyrei Hyatt ....- -- 190,191, 237-238 swallovi (Shumard) eee lite guadalupe (Roemer) ...-.------------------ 188-191, 196; 118-121, 122, 123, 134, 274, 278, 282 197-199, 200, 202-204; 206, note; 211, 213, 237, 310 whitei Hyatt 27, 128)278, 280 Metoicoceratide 115-128 Mojsisovicsia Steinmann -...-.--....----- 24-25, 26, 27, 89, 90 durfeldi Steinmann -.....:...-..--.---------- 25-26, 254 Mojsisovicsiide Hyatt -----.----------..-..--.-._..-.-- 24 Neolobites Fischer. .- choffati Hyatt -.. 58, 104, 144, 158, 178 . 178, 302 cotteaui Nickles .- Sey - 14 TOEINO OL IS FI oe Sono

-------.----..- 131, 138 dumasiana (d’Orhigny) -- 138, 139, 286 Karsten (Wie; nose clce ca =e --e--== 138 lapparenti ( Nicklés) -- 138 lenticulata (Hyatt) .-- 138 TAR (CSIC GS) ee co geetecnatpoonsacssescabs secu cosas 138 maaladcel@NICKICS)— -aneecee acne << ee neem eee 138 TG IhVay! (CSMANES) a= se sen emeqntoe sess te gece ecosseeae 138 TOV He (CNMI) Se eee oes peeesSeaseenSeCanesrscos 138 Bulchellag (MOrbigny eee seen eee eee 141 zeilleri (Nicklés) ....- 138 Odontoceras -.. 105 Oleostephanus . 102 Orthoceratites - 68 ORG AUCWCCG is os acoss aaa see Saeee Sonos abers secedcecesccs 104 heteropleurum Neumayr and Uhlig.......--------- 89-90 pseudograsianum Uhlig ....------------------------ 90 Eup yall ec sce caneeeers = 2 PAG hy CaS CUE see see ae oa ce tai aiatctwiaisle ime ele 90, 102 Paralenticeras Hyatt . - &, note; 85 sieversi Gerhardt- 85 IPATAEISSOblay Eli veubtee eee wee i a oe 41, 45, 50, 55, 143 djelfensis eh oy. on, scene 52 Hicheuriu(GLrossoluyre)eess---------+--=-= ee 40,50, 51, fourneli Grossouvre ....-..-.------ grossouyrel (Peron) .-.---.------.-- regularis Hyatt ...-. serrata (Hyatt) --- thomasi ( Peron) TNCISMM YM pAb essen eee ee eee sees intercalare Meek lenticulare Meek -.- liardense Whiteaves....---.-.--------- memoria-schloenbachi Laube and Bruder....--.-- 236 unre (ede (13 beWb (30) - ees eccces 190, 191, 288, 239 newberryi Hyatt .-..-.- 190, 191, 196, 200, 203-205, 206, 314 orbignyanum (Geinitz) -..-.----- Oe eee eee 240 (KONTO RN n poe n encasanonncososseoaseeesnon cao 192, note placenta (Dekay).-- . 190; 191, note; 196, 202, 209, 210, 211-214, 215-219, 221-228, 225, 233, 236, 330, 332 placenta var. intercalare Meek..... 207 planum Hyatt. -.-.. 190, 191, 196, 202-203, 204, 211, 318, 320 polyopsis (Dujardin) ...------.----------------- 240-241 pseudoplacenta Hyatt — -- 189,190, 196, 214, 216-217, 232, 338, 340 var. occidentale Hyatt -.....----------- 217 0, 342 pseudorbignyanum Hyatt ..-..-.- 240, 242 requienianum d’Orbigny -.--..-- pane 236 sancarlosense Hyatt -... 191, 196, 200, 202, 206, 211, 312, 514 var. pseudosyrtale Hyatt---.--....--------------- 190, 191, 197, 199, 200-202, 316, 318 236, 239, 241, 242 233, 346 189, 190, 196, 214, 217, 218, 233, 235 207, , 332-338 susctoodses 242 schliteri Hyatt spillmani Hyatt stantoni Hyatt -..-..---. yar. bolli Hyatt subtilistriatum Jimbo.... syrtale (Morton) 2, 189-191, 196, 198, 200, 06, 208-213, 215, 217, 220, 221, 232, 233, 236-239, 242, 306, 308 Wh lol ISG wae Pec enc deem cedeacnsoe 205, 206-207 syrtale var. quadratum Grossouyre tamulicum (Blanford) .....-.-------------- 236 telifer (Morton) .....---.----------------------- uhligi Choffat ...---.------- warthi Kossmat .- whitfieldi Hyatt - 8, 209, 211-220, 221-232, 191, note; 196, 20 yar. tuberculatum Hyatt.-..-.-- 209, 214, 220, 221, 232 Placenticeratids ........--..--.------------------++- 188-245 Platylenticeras Hyatt...-..----------- $4, note; 85, 88-89, 2 gevrilianum (d’Orbigny)-.------------------------- $4, § | heteropleurum (Neumayr and Uhlig) -.--- 89-90, 99, 244 pseudograsianum (Uhlig) ...--.---------------+-- 89,90 350 INDEX. Page. Page. Plesiotissotia ........ .-34,41 | Roemeroceras Hyatt—Continued. michaleti Peron . 41 Babbilyatte. oan even el eee eee eee nee 30, 31, 256 Rolyplectusicapellinus=esssseeeeesseeseeee eee eee eee 19 subplanum Hyatt .- Se EBA 256: ISCO CS Sees Atte a ence esos YARN Ea os 19 syriaciforme Hyatt . 30, 31-32, 33, 34, 37, 254 PLIMMOLATATT cas ee ee oy eV yatre tal in a 294: Scaphites thse 3 i eae a eo 189 Prionetropidre y= se sepa een te eee eee cee oe See 245270 ep ochiloenbachiaes sess eee Sear eee ae ee eee eee eee 191,193 Prolecanites Assess ee aa e ese a en a 745 eSchiluetericerasielyattee eee eeeeeeeee eee eee aeeeee 110-111 Protensonoceras/Hyatteeeesseeeeece ese ane eee oeenee ae 20, laubeith yatta iy ssh ok See oe ee ee 111 153, 157, 158, 179, 181, 186, 188, 189, 192, 198, 204 michelobense... 111 emarginatum’ (Cragin) --------------------- 154, 157, 176 TmOdOSOLdesi(ScChiiten) =a esses =a aee ese eee 110, 111 gabbi (B6hm) .....-.-. - 153-156, 176, 286 vielbanci (d’Orbigny) .-- con’ lilt) planum Hyatt ....... ... 156-157, 288 | Sharpeiceras Hyatt .:...-.- eek) Pseudaspidoceras Hyatt - -- --- 106-107, 116 inconstans (Schliiter) - oe ablilpable) cConciliatumy(Stoliczka)ees=seese cesses eeseeeeeeeeee 107 laticlayiumy® (Sharpe) sesecsseneeeeaceneeeeteeeeeee Talal, WiiB} crassitestan(Stoliczia)ieeeene ee ae eee aeeeee eee aes 107 schlueteri Hyatt ‘ 111 Gumilifik(Stolicz ica) ieee e nee eeseeeeere eer eere eee 107 | Sigaloceras taylori.. 106 deciduumeEbyattsssenetcecack seo eee eee Ov MOPECGLESNClassinedul Stole esses eee eeee heer eee eee 15-18 evomphalumi(Sharpe)imesseeseeee eee eee tesa eer ee 107 | Specific differences, absence of, in Placenticeras...--. 196 footeanum (Stoliczka)-..-..22..--.22.-=-.------- WONG OTS) |] Solway WOES Srescsseccsscccascoceseseescooneecas SChIlUteriseby at paee eee eee eee eee ees 107 | Sphenodiscus Meek. Pseudoceratites, definition of 54-57, 58, 83, 87, 91-95, 149, 153, 160, 180, 195, 233 Pseudophyllites Kossmat. -.-- Ws ACULOGONSAMUSPNOC LLIN pap ee ee ee eee eee eee ee 57 Pseudotissotia Peron -.. 3: GCXOWIN MIT boo aos doasoSbosaoskacceccenuE Eo 58 Canmonan Chon steaeeeeeee eee ne eee eee eee 37 beecherivebyattaesser ees eee eee ae 69, 78-82, 264, 270 douvillet Peron 38 belviderensis var. serpentinus Cragin ..-...------- 162, 164 galliennei(G/Orbigmy)je-essssees onenee ene. 35, 36, 37, 42 belviderensis var. wddent Cragin.--...-.-.---------- 159 ATLESLETSE CLOM aie oe et eA DR DRE Dee egee aA 37 DUN CSHOTSties Obese eee eae ee 58, 82 TUMISLeNSISHEy abhi ereN Nee eer eee eee 36-37 Gaumdle\ Cragin Sie sa eA ay tne Beene eee Ue 185 Bseud otissonideeiehy att -eeeeseee noe eee ae ee eee 24;34-35 HOGG URAS CHASM 3 ce oe obas obbcasoacoesooscoces 157, 177 PSiLO eras uae eRe eA & rite ciepal ped egy NR): MaMa 24,25 TSTECHISYZAGGE we ye Nee alt ON ee a tae es pare 58 Psiloceratide: - ae 25, konincki Hyatt... 82, 276 IPsilopullchelliiaiee-eerecere eee eee ene er oe eee 136, 137, 142, 143 Jenticularis (Owen) - Bamasoar tau, Psilotissotia Hyatt. -- 41,187,140, 141, 143 58, 66, 70, 71-75, 77-82, 94, 95, 268, 270 chalmasi (Nicklés) 148 Val yO AEM CUS See eee ene ee eee eee eee 76 defforgesi (Nicklés) 143 yar. mississippiensis Hyatt....-..--- 77-78, 80, 81, 270 agi (NCK1ES) eee eee ee eeicc as ee eee 148, 144 var. splendens Hyatt .....-..-.---.- 95-77, 79, 80, 268 ian naoVesy (INNES) soppy soto ations roneseneucsdeness 143 lobatus (Tuomey) -.- 65, 66-70, 71, 75, 76, 80, 82, 264, 266, 270 Reig in (NICHI OS) Meese eneaee eis sooo eee ee eee 148 Dleuriseptay (CounaC) esse eee eee eee eee 57, PulchellianWihlic epee emcee pee e es ee eee ee 41, 58, 59-65, 70, 71, 75, 82, 258, 260, 262, 264 55, 112, 117, 129, 181, 186, 137, 1389, 140-142, 144 requient Grossouyre 100 Caicedii (Karsten ener cece cee ce eee 130, 135 roemert Cragin ...- 177 changarnieri Sayn. ie 142 rutoti Grossouyre. se 83 columbiana....-. a SUNS eI EE Te A I See ag eh 142 SHAWN Pols) Sasconaddasacscesaan= soso co AMscansiocos $3 compressissima (d’Orbigny) 141, 142, 286 stantoni Hyatt..----.-.-.----:---_--.-- 70-71, 81, 262, 264 COT LOVING CLES a eed tetera tet Ue tet nial Toon cn 130 ubaeshiiGrossouvilee eee eee eee nee eee eee 82,83 GeflorgesiNiCkl Gs hese oes eee eee aoe eee 143;:\(Stepheocerasss28o2a-s8s-t sees aeseoee seasons 102 GidlnytG-erb ard tee cesta pte 1364 |matepheoceratid ce saasesseeseeeeie ce eee eee eee eee 102 TOUMUCTENIC KGS teeter ete ere ee ee eet 139}4| mSUCULOCEras| COssm a yeaseeeeeen sees n aaa eae eae aaet 105 LOOT ADE ea Ar coger gf cates Se NES ye aL) See ae 143 || Stoliczkaia--.-.-.-..--- - 104, note; 137, 140, 141 heme SaryMicie ess coerce oe ae eee ee ee ee 130 tetragona Neumayr - poe del hettneri: -=-2- = 142 | Styracoceras Hyatt -.-.. op -.-- 83,88, 244 PRON TD ONON UOT eae ae tae eee eee ee oe eee 138 baldurne(eyserlamg)))e este eae ase eee 89, 244-245 kaliamieeeeeeeer . 183,142 | Subpulchellia Hyatt ............-...-..-.-- 136, 137, 189-140 Mi Chel Csiskhy atten Marie ae one ace ieee gon). 1 Castellamensisheby aubeeRe se seeeeeeer emer eeeeeser 140, 286 OA RNOINIOMESS cos nsaesroqosspeopscoscec e139, IHOUCG AULENL, (INPIONNAS) eo sscacssesnnoebran csoseescee= 139 QuaeheNSISIS aye eens eee Beene rere 133, 142 Oe hVertiN (NUCICS) Weper eens tee te eanen ee neesere 139 provincialis d'Orbigny ......-....-...-..-- 129, 130, 131, 134 sauvageaui (Hermite) .........-......-..---..-- 139, 140 PULCREULCRGAONDI STAVE eee eee eee 138, 140,141 | Subtissotia Hyatt..........-. - 38, 42, 43,45 SCLUUAGECUIAELCLINIITC Reese ee sae ee eee eee 139, 140 africana (Peron).... =e 44 schlumbergeri Nicklés . Fen inflata (Peron) ..- ---- 43,45 selecta Gerhardt........ een (49) ThaeroanXeXobtD), (EEWOIM)) ono soa socooaeaoaossoeonoensS 43-44, 45 SILO CONCERN ee eee eee eee -.. 129,130 EON JENA, oscs0 ssocosmsconcosoouasbRSooODScbere 44 Pulchellii dees. pecs seeee 80101-5104 note si7t299136—1450 |) nachy senesiceen-eeeeetee estes seee eee =e ee eeeeee 22, 23 Retardation in development ..../........-..-- 20=2381S9=190 i | meReg OCELASPELY al lENeree eee eee stele eee eter 83, S4 Roemeroceras)Hyatt/-. 205252. 2 ses ee ee 26, 30, 36, 112, 145, 192 TM OSEDSC aes se eeee cree en eee aes ee ee eee eee 84, 87 attenuatum) (Hyatt)~ oo ot nee eee ene ee $3,254 | Terminology employed.....-..-.....--..--.....-.--.-- 11-14 demticula tums ee ke Sopa em oar leer ae er eee 84 | Tissotia Douvillé............ 32, 35, 36, 38, 41, 42, 45, 55, 104, 178 INDEX. Tissotia Douvillé—Continued. ‘ Page. | Tissotia Douville—Continued. UPRLCCITAD CLO Lseenete as = sateen oie ot ene cect 44 curessensis Peron .....-..- Shoes eSsdosco ss boss shes 49 cossoni Peron ...-. fereeralore ie Seite sae sc etelamt oe ee err 54-55 Fy CUTENS Ope LOD ewan io eects stat acters eae 40 CWOlde VON BUCH) eeeseeenee cases ees cmececiee 44,45,46,48 | Tissotiidee Hyatt~ Mic ieume GLOSSOUVI Cen eeneeee ans seeee ee aaaeeecle 51 | Tolypeceras Hyatt. POUNTLELUBCTONEM antes se at\s ok sacar sfonae aabieee 36, 45, 49 | PIODOSAREV ALUN eee re eS ek a eee aa 55 | Traneceras grossouvret Peron haplophyllaiGrossOuyre =~. <-.2-----2 e322 ence so ee = 47,48 IEA EEG kaos adds bane Gone ane eee EGS ea ReGa Eee eaeee 44 POVXIRO (CRROS SOV ANG) 5 Seong pone soon ceeeane se noasebes 44, 46 serrata - sli thomasi Peron... tissoti (Bayle) marcousannm - socd tho seTosrEcisedoconsdenessoens 50 | Vascoceras Choffat hartti (Hyatt) subconciliatum Choffat. .. 351 Page. 192 49 -- 50,55 42, 48, 52 24, 26, 30, 34, 35, 41-56, $4 .--- 101, note; 103-104 103-104 25 101-102 - 103,250 101 PUBLICATIONS OF UNITED STATES GEOLOGICAL SURVEY, [Monograph XLIV.] The serial publications of the United States Geological Survey consist of (1) Annual Reports, (2) Monographs, (3) Professional Papers, (4) Bulletins, (5) Mineral Resources, (6) Water-Supply and Irrigation Papers, (7) Topographic Atlas of the United States—folios and separate sheets thereof, (8) Geologic Atlas of the United States—folios thereof. 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U.S. Dept. of the Interior. see also U.S. Geological survey. Ill x il ! lh 26 ! | | | | | | | 3 9088 01363 | x a 3 z o = =} |= = a —S z s z fo} a x [ee = 7) —— apr ean oom wean arian eae sa ane on won . paneer netaree ieee Scagretnj eves ab agayauey ati