ilS) im • m - m = a - m S CD = a s CD S rn = D ^ o DEPARTMENT OF THE INTERIOR. REPORT UNITED STATES GEOLOGICAL SURVEY THE TERRITORIES. F. V. HOYDEN, UNITED STATES GEOLOGIS T-I N-CHAEGE VOLUME III. WASHIJSGTOlsr: GOVERNMENT FEINTING OFFICE. 18 84. :n^ote. Department of the Interior, United States Geological Survey. On the 27th of September, 1882, at the request of Dr. F. V. Hay den, the completion of the pubHcations of the United States Geological and Geographical Survey of the Territories, formerly under his charge, was committed to the charge of tlie Director of the Geological Survey by the following order from the honorable the Secretary of the Interior : Department of the Interior, Washinffton, Septemher 27, 1882. Maj. J. W. Powell, — Director U. S. Geological Stirvei/, Citi/: Sir: The letter of Prof F. V. Hayden, dated June 27th, bearing your indorsement of Jul}* 20th, relating to the unpublished reports of the sur- vey formerly under his charge, is herewith returned. You will please take charge of the publications referred to in the same, in accordance with the suggestions made b}' Professor Hayden. It is the desire of this office that these volumes shall be completed and published as early as practicable. Very respectfully, H. M. TELLER, Secretari/. Of the publications thus placed in charge of the Director of the Sur- ve}^, the accompanying volume is the first to be issued. It is understood that its preparation was begun in 1871-', by the transmission of a part of the manuscript to the Public Printer. (iii) IV NOTE. At the tiuie wIr'U tlit- wcnk was tunitd over to the Director oi' the Geological Survey an important portion of the manuscript was yet unpra- pared ; l)ut, throui^h tlie energy of Professor Cope, the volume has been raj)idlv brought to eomjjletion. Tlie work coustitutcs a vahiable oontrilm- tioii to |iak-()iitology, and is a iiiniminent to the labor and genius of the authoi- and to the administrative talent of Di' llavden. 1 lie yet unpublished volumes will be pushed to completion at an earlv day. Director U. S. Geological Survey. Washington, September II, 1883. / ^-/ LETTER OF TRANSMITTAL- \ Washington, January 1, 1883. Sir: I have the honor to transmit for 3-onr approval the third vohnne of the series ot final reports of the United States Geological Survey of the. Ter- ritories, which during its existence was nnder my charge. Tlie present volume, which has been prepared by the eminent paleon- tologist. Prof K. D. Cope, of Philadelphia, represents the labor of several years, both in the field and in the study, and may l)e regarded as one of the most important contributions to the rich field of vertebrate paleontology of the western Territories ever made in this country. It was the original purpose to include all the material in the author's possession from the Cenozoic and Mesozoic formations in the third and fourth volumes of the series, but they accumulated to such an extent that it became necessary to limit them to the Cenozoic alone. Therefore, the two volumes are essentially one in subject matter. This volume consists of 1002 pages of text, illustrated with more than one hundred plates, and the fourth volume, which is to follow, may be regarded as a continuation of the present one, both comprising the material in the author's possession from the Cenozoic formations of the West. The two volumes are divided into four parts, viz: Part I, Puerco, Wasatch, and Bridger Faunse (Eocene); Part II, White River and John Day Faunse (Lower and Middle Miocene) ; Part III, TicholejDtus and Loup Fork Faunse (Upper Miocene); and Part IV, Pliocene. vi LETTER OF TRANSMITTAL. The present volume includes Part I, and the first j)ortion of Part II as far as the Ungulates; including, therefore, the Marsupials, Bats. Insectivores, Rodents, and Garni vora of the Miocene. Part I includes the folh)winL'' ninst important contrihutions to paleon- tology and evolution: 1. The discovery of the fauna of the Puereo Gruu)), <>f thirty genera and sixty-three species. This includes many important details, such as the discovery and definition of three new families, with many species of a new order, the Taxeopoda, as the PeripUfchidcE, Meniscotheriidce, and a new sub- order, the Taliffrada, represented li\' tlie genus Pantolamhda ; also the dis- covery of the Plagiaulax type (of the Jurassic) and other Marsupials, and the Laramie Saurian genus Champsosaurus in the Puerco Group. 2. The new classification of the Ungulata rendered possible by the dis- covery of the complete remains of the Wasatch types of Pheuacodns and Coryphodon, especially the former, from Wyoming Territory. The light thrown on the phylogeny of the Ungulata by this discovery exceeds that derived from all other sources together. 3. The new classification of the lower clawed niaimnals, liased on the analyses of fifteen new genera- and forty-seven new species of fiesh-eaters, and six new genera and sixteen new species of allied forms, all discovered since the publication of the author's volume in connection with the Wheeler Survey. 4. The restoration of Hyracotherium, the four-toed horse of the Wasatcli Group. h. The restoration of the genera TripU)piis and llyracliyus of the Bridger Fauna. 6. The detenniiiatidii of tiu; systematic relation of the Dinocerata as seen in the genera Loxolojihodon and Bathyopsis. The wiiole mnnber of genera described in this volume is 125, and of species .■J4!i, of which 317 species were determined by Professor Cope. The explorations that furnished the materials for these volumes began in 1872, and are still being continued. If will tlierefore be readily seen that the amount of new matter towards tlie origin ami history of the Mam- LETTER OF TRANSMITTAL. Vll malian group brought together by the author iu these two volumes is most extraordinary, and will probably never be surpassed. The plates which illustrate this volume were engraved by Thomas Sin- clair & Son, of Philadelphia, and the figures were drawn on stone from the specimens themselves, under the immediate supervision of Professor Cope. At the close of the fiscal year ending June 30, 1882, at my request, the Secretary of the Interior placed the printing of the uncompleted vol- umes of the quarto series in the care of Maj. J. W. Powell, the Director of the United States Geological Survey, and I desire him to accept my cordial thanks for his very kind attention and for many personal courtesies. Very respectfully, your obedient servant, F. V. HAYDEN, United States Geological Survey of the Territories. The Hon. the Secretary of the I^TERIOR, Washington, D. C. UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. THE VERTEBRATA TERTIARY FORMATIONS OF THE ^V^^EST. Book I. By EDWARD D. COPE, MEMBER OF THE NATIONAL ACADEMY OF SCIENCES. WASHINGTON: GOVERNMENT PHINTINO OFFICE. 1883 . CONTENTS, Page. Letter of transmission xx Proftice xxiii INTRODUCTION. Section I. The Tertiary Formations of the Central Region of the United States 1 TliePiiorco- 4 The Wasatcb iJ Tlie Bridger 11 Tlie Uiuta 1^ The Wliite River 13 The Loiip Forlv 16 TheEquus Betls 19 Section II. Thi; Horizontal Relations of the North Americ-vn Tertiaries with those of Europe. . '27 r A KT FIRST. The Puerco, Wasatch, and Bridger Faun^ 40 Pisces 49 Ela.snioliranchi 49 Xiphotrygon 49 Xipbotrygon acutidens 50 Ginglymodi 52 Clastes 53 Clastes anax 53 atrox 54 cycliferus 54 ciiueatiis 55 Hali'coniorphi .56 Pappichtliys • 56 Pappichtliys solerops 57 liC'vis 58 jjlicatns - 59 corsoni 60 Neniatogiuithi 61 Rhineastes 62 Rbineastps peltaUis 63 sniithii 64 c al vTis 65 arcuatiia GG Taduhi.s 67 Isospondy li 67 xi 5^5^0 Xn CONTENTS. The Pukrco, Wasatch, Axn Dridgkr Fauk^— Continued. Pisces : Poze. Daprdiiylossiis W Da|)cdoglossu8 cnoaustus 70 testis "1 acutus "2 tequipinuis '<3 Diplumystus "•! Diploniystus clcntatus *4 anulis "5 pcctorosns 76 theta "7 liiimilis 77 alius 79 Percomorpbi 79 Erisuiatoiilerus SO Erisniatoptenis levatus 80 rickseekeri 81 endlichi 82 Auiphipla'^a 83 Anipbiplaga brachyptera 84 Asiucops 84 Asiucops squamifrons 85 panel radiatus 87 Mioplosus 88 MioplosuH abbreviatns 83 labracoides 89 longus 90 bcani 91 sau vageanus 92 Priaoacara 92 Priscacara scrrata 93 cy pba 94 oxy prion 94 olivosa 96 pealci 96 Hops 97 testudiuaria 98 Batrachia 100 Rcptilia 101 Opbidia 102 Protagras 102 I'rotagras lacustris lOJ Laot^rtilia • 104 Chori.ttodcra 104 Cbanipsosanrus 1H4 ChainpHosannm australis 107 pucrconsis 107 saponeusis 109 Testndinala Ill Axcstus 116 Axnstus byssinns 116 Trioiiyx 117 Triouyx radnlus 119 fjnttatus 119 betrroglyptns 120 CONTENTS. XI li The Puerco, Wasatch, and Bridgek Faun^ — Continued. Eeptilia : Page. Triouyx coiicentricus liiO soutiimantiquum 121 Plastomeuus 1^2 Plastomenus trionychoides Id^ multifoveatus 124 molopinus V& cedemius 126 Anostira 127 Anostira radulina 128 oriiata 128 Emys 12» Emys polycypha 131 - terrestris 131 megaulax 132 euthnel a 133 testiidinea 134 vyoiniiigeusis 135 shaugbuessiana 135 hay deiii 137 l.atilabiatus 138 septaria 139- Hadriamis 140 Hadrianus allabiatus 140- octonaiius 140 corsoni 141 Dermatemys 142 Dcrmatemys vyomingensis 142 Notomorpha ■ 142 Notomorpha gravis 143 Baeiia 144 Bauiia Lebraiea 146 uudata 147 areuosa 148 ponderosa -T 150 Crocodilia 151 Crocodilus 151 Crocodilus subulatus ]. . 152" polyodou 154 acer 154 sulciferus 157 clavis 157 affiuis 102' hetcrodon I(i4 Mammalia I'j'^ M.irsnpialia ^. 1(|7 Catopsalis 170 CatopsaJis foliatus - 171 Ptilodus ■- 172 Ptilodus medisBVUs 173 Rodeutia 175 Plesiaixtomys 1^5 Plesiarctomys buccatus 179 delicatissimus l''J delicatior lf'2' XIV CONTENTS. The PvKitco, Wasatch, and BRiDGEB.FAUNiE^-Goiitinned. Muiuiiialia : Pagi'. ISiuiutburiu I'io TuiuindoDta 187 Culaiiiodou - ItSe Calaraodou simples Iftt cylindriler 192 Ta-niolabis 193 T;i-niolal>is scalper 193 Tillodouta 194 Psittacotherium 19r> Psittacotlieriiini niultilragum 196 aspasiaj 190 Insect ivora 19* Couory ctes 198 Conoryctes comma 19s crassicuspis 201 Estboiiyx 202 Esthoiiy X biirmeisteri 204 acutidcus 210 spatulariiis 211 "Mesodnuta 211 Microsyops 21C Microsyops spierianus 21(> elogans 217 scottianus 217 Toniitlicriuiii 218 Tomitberiuiii rostratum 221 Pelycodus 224 Pelycodiis pclvidens 225 jarrovii 228 t utus 228 Irugi vorus 230 augulatus 231 Sarcolemur 233 Sarcolemur pygma;us 233 Hyopsodus 234 Hyopsodiis powelliauus 235 leuiuiuiaiiiis 236 ])aiiliis 2il7 vioarius 237 iuolytns 238 Prosiiiiis 239 Mixodcctc8 240 Mixodectes jmiigeus 24 1 rrassitisculus 242 Cynodonloiiiys 243 Cyiiodoiitomys latidons 244 Aiiaptoniorphiis 24."> Aiiapt(>iii(ir|>liiiH lumiilus 248 liomunculns . 249 Creodonta 251 Ictops 265 Ictops bicuspis 2'i6 didelplioides 2t>s CONTENTS. XV The Puerco, Wasatch, and Bridgeu Faun^— Continued. Mammalia: Page. Peratherium .■ ; j ~6tf P«ratherium comstocki 2G0 Tri'isodou ......;. '-i'i> Triisodon quivireusis , i2T2 heilpriuianus '27'.i levisanus ^ 273 eonidens ^ ^... — 274 Deltatherium - . 277 Deltatberiura fundamiuus »■. i 278 baUlwiui ^ 232 interrupt lira -. 2ri2 Didtlphodus ---- 283 Didelphodus absarokce 284 Styiwlopbus ....1. 283 Stypolophus insect! vorus 290 pungeus 291 brevicalcaratus - -.- 291 wbitia? 292 aeuleatus 299 Miaois - - 301 Miacis canavus 3il2 brevtrostris 30;1 parvivorus - 304 Didymictis.. 304 Didymictis baydeuianus ^. 30Ci altidens 307 leptomyliiB 309 dawkin--ianus 310 protenus 311 Oxyseua 313 Oxyrena foreipata - 31m Protopsalis 321 Protopsalis tigrinus 32v! Mioclienus 324 Mioclcenus t urgidus 32.'i minimus 327 baldwini 32>i feros . - 32.~ subtrigouus 338 mandibularis 339 protogonioides 341 1 bucculeutus 341 coiTuj;atus 341 Acbsenodou 342 Acb;vnodou insolens 343 Dissacus 344 Dis.s;K'Ud navajuvius , 34.") caruifex 345 Sarcotbraustes 34 i Saicotliraustes antiqnus 347 Mesonys 34~ Mesony.K obtusidens - 3:3 lanlns 358 ossifragus SC- XVI CONTENTS. TiiK PfERCo, Wasatch, AXr> Bitiixii-ii Faun^— Continued. Maoiiuuli.t : Page- CbiruiitiT.i 3T:t- WspcTiigo :$T3 Vf»|iiTiigo ancmopUilus 374 Tiixi'opoda 374 Tuxeopodii 37"^ Proboseidi a :r79- Amblypodu 37"> Uiplarthni 37> Condylarlbra :iS-> Periptj'cliiduj itiS,') Plu'iiatodoiitiiUi' 3!:6 Meniscotlieriida; IJgO. Pt-ripljcUus 387 Pt-ript ychus lUabdodoii 3f?i> cariiiideUH 405 di(rigonu8 404 lK-niilUKeii» 405 Heiiiitbla;u8 kowalevskiaiius 40.> opiiitbacuH 407 AuisuucUiis 408 AnisoiicbuN coiiifenis 409" );illiaiiu8 411 Kcctorius 413 HapUiciiniis 415 Haploconiis aiignstus 410- liiioatHS 417 xiphodou 4->0 fulocouus 421 Pr<>to;;oni.i 424 I'roiojj;ouia idicilVr.i 424. siiliqnadrata 4'2G Aiiucoildn 427 Anacndon ursidcns 427 Pht-naciMlus 428 I'bi'iiacodii.s niiniuiius 434 prinucviis 4;i5. lii'iiiii'OiiiiH 4G3 vortniani 464 calceulatus 487 pucrccnsia 488 inacropfoniiiH 490 brachyiitcrnus 47 Hyrachyus princeps 661 sp 661 eximius 662 II C XVlll CONTENTS. TnE PiT.nro, Wasatch, and Bridger Faun^ — Continued. Mammalia : Pnge. Hyracbyus agrarius 675 implicatiis 676 TriplopodidiB 676 Triplopus 678 Triplopus oubitalis 679 amarorum 687 HyracodontulsB 691 Ehinocerido) 691 T,-»piri(liu 69:t Chalicotheriidao 694 Ectociou 690 Ectocion osbomiannm 696 PalsBOsyops 697 PaliBosyops vallidens 699 major 701 Iffividens 701 borealia 70;J Limnohyus 705 Limnohyus diaconus 70(> fontinalis 707 Lambdot helium 709 Lambdotberium brownianum 709 popoagicum 710 procyoninum 711 Macrancheniida 712 Menodontidie 713 PalcBotberiidte 7i:i Equidie 715 Artiodacty la 716 Omnivora 710 Pantolestca 717 Pantolestes chacensis , 719 bracbystomus 721 metsiacus 719 nnptns 720 etaagicns 724 longicaudns 725 secans 725 Addenda to Pakt First 727 Pisces 727 Pcrcomorphi 727 Plio|ilarcliU8 , 727 Plioplarcbat) whitoi 72ft scxspiuoaus 729 Rpptilia 730 Ophidia 730 Helagras 730 Holagras prisciforrais 730 Mammalia 732 Poly mastodon 732 Poly mastodon taoonsis 732 Cato|miiliH 7Xi Catopsalis pollnx 7;$4 Disaaciis 74 1 CONTENTS. xix Page. Supplement to Part First — The Amyzon Shales 742 Pisces 745 Halecomorphi 745 Amia 745 Amia scutata 745 dictyocephala 745 Nematognathl 747 Ehineastea 747 Ehineastes pectinatus 747 Plectospondyli 748 Amyzon 748 Amyzon men tale 749 commune 749 pandatum 750 fusiforme 751 Percomorpbi 752 Trichophanes 752 Trichophanes foliarum 753 hians 753 Aves 754 GraUiB 755 Charadrius 755 Charadrius sheppardianns 755 PART SECOND. The White River and John Day FACNiE 760 Reptilia 761 Testudinata 762 Testudo 762 Testndo cultratns 763 qnadratns 704 laticuneus 765 ligonius 766 amphithorax 767 Stylemys 769 Stylemy s nebrascensis 769 Lacertilia 770 Peltosaurus 771 Peltosaurus granulosus 773 Exostlnus 775 Exostinus serratua 776 Aciprion 776 Aciprion f ormosum 776 Diacium 777 Dlaciam quinquipedale 777 Platyrhacliis 777 Platyrhachis coloradoensis 778 unipedalis 779 rliambastes 779 Cremastosaurns 780 Cremastosaurus carinicollis 781 Ophidia 781 Aphelophis - 781 Aphelophis talpivoms 782 XX C02JTENTS. TiiK White Hivkr and John Pay Faun^ — Continued. Replilia: Pkge. Ogmophis 't?- Opnophis oreponensis 783 augiilatus 783 Calamagras 784 Calaiiiiijjras murivorus 784 Nearodioiiiii-iis 7'io Neiirodroniicus dorsalis 786 Maninialia 786 Marsdpiali:) 788 Perathprium 789 Perathcrium fiigax 794 tricuspis 796 huntii 796 scalare 797 niarginalo 798 altt-ruaiia 799 Bnnotheria 800 Creodoiita 800 Mesodoctes 801 Mesodectes caniciilus 805 Geolabis 807 Geolubis rhynchaeus 808 Insect ivora 808 Menotlicrinm 808 Menotherium lemurinum 809 Chiropttra 809 Doniiiiiia 810 Douinina gradata 810 crassigenis 811 Kodentia 812 Seiuromorplia 81G Scinrus 816 Scinras vortmani 816 relict us 817 balloviauus 818 Gymnoptychus 819 Gyiunoptychnsminutus 822 trilopLus 826 Meuiscomys 820 Meniscomys hippodiis 828 lioluphus 829 Meniscomys cavatus ' 830 niti-ns 832 Iscbyroinys 833 Iscbyromys typus 835 Castor 838 Castor pcninsiilatus 840 gradatns 844 Heliscoinyg 845 HcliBComys vet us 846 Myoniorpba 848 EnmyH 848 Euniys elogans 849 CONTENTS. XXI The White River and John Day Faun^— Continued. Page. Hesperomys So- Hesperomys nematodon 853 Paciculus ^53 Paciculus iusolitus 8.54 lockiugtonianus 854 Entoptycbus *555 Entoptychus planifrons 858 lambdoideus 860 minor 861 cavifrons 862 crassiramis 864 PleurolicuB 866 Pleurolicus sulcifrons 867 leptophrys S68 diplophysus 869 Lagomorplia 870 Palseolagus 870 Palffiolagus haydeni 875 trijdex 881 turgid us 882 LepuB 885 Lepus enniBianus 886 Cami vera 888 Amphicyon 894 Amphicy on vetus 894 hartshomianus 896 cuspigerus 893 Temnocyon 902 Temnocyon altigenis 903 wallovianus 905 coryphseus 906 Joseph! 912 Galecynus --• 914 Galecynus gregarius : 916 lippincottianus 9)9 geisniarianus 920 latidens 930 lemur 931 Enhydrocyon 935 Enhydrocyon stenocephalus 935 OUgobunis 939 Oligobunis crasslvultus 940 Hy senocy on 942 Hyisnocyon basilatus 942 sectorins 943 BtinsBlurus 946 Bunselorus lagophagus 946 osonim 947 NlmravidsB 947 Arcbfelurus 952 Arcbselurus debilis 9^3 Nimravus 963 Nimravns gompbodus 964 confert us 972 XXII CONTENTS. The White Riveu axd John Day Faunae— Continued. Reptattki Page. Dinictis 973 Dinictia cyclops 973 felinn 978 Bqnalidens 979 Pogonodon 981 Pogouodon platy copis 982 brachyops 987 Hoplophoneus 992 Hoplophoneus creodontis 993 cerebralis 997 strigidcns 1001 LIS!" OF -W O O D - C XJ X' S . Fio. 1, page 4. — Section west of tbe Galliiius Mountains, New Mexico, from Gallinos Creek to the Eocene Pl.Ttcau (Cope). Fig. 2, page 5. — Section along the east side of tbe Animas River, Colorado. (Hayden.) Fig. 3, page 6. — Section on the San .Juan Kiver, Colorado. (Hayden.) Fig. 4, page 8. — General section in the Yanipa district. (Hayden.) Fig. 5, page 13. — Scene in tbe Bad Lands of tbe White River formation in Nebraska. (Hayden.) Fig. 6, page 16. — Section in Eastern Colorado. (Cope.) Fig. Co, page 20. — Sand Hills, Northwestern Nebraska. (Hayden.) Fig. 7, page 2o7. — Distal extremity of tibia of Amhlijctonua tinotus Cope. Fig. 8, page 257. — Distal extremity of tibia of Oxytcna morsitans Cope. Fig. 9, page 257. — Portions of maxillary and mandibular bones of Ozyatna lupina Cope. Fig. 10, page 258. — Mandible of Oxi/cpna forcipala Cojje. Fig. 11, page 375. — Left anterior foot of Elephas africanua. Fig. 12, page 376. — Left anterior foot of I'henacodiis primcevm. Fig. 13, page 37G. — Right anterior foot of Hi/rax capcnsis. Fig. 14, page 376. — Right uiauns of Corijphoilon. Fig. 15, page 377. — Fore leg and foot of Iliiracolhenum renticolum. Fig. 16, page 378. — Left posterior foot of I'henacodus primccvua. Fig. 17, page 378. — Right jiosterior foot oi Hyrax cupcTitia. Fig. 18, page 379. — Posterior foot of Cori/phodon. Fig. 19, page 379. — Left pes of Elephas indiciis. Fig. 20, page 380. — Hiud foot of I'oHhiolherium lubiatum. Fig. 21, page 514. — Skull of Coryphodon clephantopus, displivying brain cavity. Fig. 22, page 515. — Right posterior foot of a siecies of Coryphodon. Fig. 23, page 522. — Profih; view of skull of Coryphodon clephantopus, from Now Mexico. Fig. 24, page 522. — Superior surface of skull of Coryphodon clephantopus. Fig. 2.5, page .533. — .Sknll of Coryphodon cUphanlopus. Fig. 2.'a, page 584. — Loxolophodon cornulus Cope; restoration. Fig. 26, p.age 599. — Uintalherium Icidianum ; from Osborn. Fig. 27, page .599. — Superior molar teeth of Uintalherium Icidianum; from Osboru. Fig. 28, page 599. — Loxolophodon spicrianum; from Osborn. Fig. 29, page .599. — Mandible of suppo.sed Loxolophodon; from O.sborn. Fio. 29n, page 599. — Inferior molars, external side; from Osborn. FlO. 30, page 599. — Inferior incisors of «up|i<)sed Aoxofiy/Ziorfoii, external and superior views; Osborn. Fig. 31, page 618. — Part of right maxill.iry bono of Jlejitodon singularis Cope. Fig. 32, page 789. — Skull of opossum (l)idelphys rirginiana). Fio. 34, page 939. — Oliyvbitnia cransirnllus Cojie ; part of skull wiHi lower jaw. Fio. 35, page 945. — JElurodon irheclirianus and Ai. hyacnoides Cope; jaws. Flo. 36, page 945. — JElurodon /•o'eus Lcidy ; skull with lower jaw nearly complete. Fig. 37, page 9.'>2. — .IrchnhiruK drhilis Cope; skull from below, showing foramina. Fig. 38, page 9HV.'. — I'ogonodon plalycopis Cope; skull, prolile. LETTER OF TRANSMISSION. January 1, 1879. Sir : I send herewith a report on the Tertiary Faunae of the United States as represented by collections made in various Territories and States west of the Mississippi River, embraced within the boundaries of your sur- vey. The explorations from which the collections have been derived cover portions of the States and Territories included between British America on the north, the western boundaries of Minnesota and Missouri on the east; the northern borders of the Indian Territory and Arizona, and the middle of New Mexico on the south; and the Sierra Nevada on the west. The amount of material which I have procured through these explorations is large, and is but partially represented in the following pages. I trust that you will find the results a useful contribution to the records of your Geo- logical Survey and to the science to which you have devoted your life ; and that you may find in this report some compensation for the arduous official duties which have recently withdrawn you to some degree from your chosen field of research. The preface gives an account of the methods pursued in conducting the investigation ; while the introduction embraces a general view of the stratigraphy of the Tertiary formations of the West. The system adopted is that proposed by yourself and Mr. King, with a few additions ; while several correlations with the horizons of the Old World are based on my own paleontological studies. The order of succession of faunae is observed in the following sections of the work; that is, part first, the Puerco, Wasatch, and Bridger formations ; part second, the White River and the John Day beds ; and part third, the Loup fork and Equus beds. The second half of the second part, the third part, and faunal lists, will constitute the succeed- ing volume. No. IV, of your series. I desire to express here the obligations under which I have been placed Xxiv LEITER OF TRANSMISSION. through the important aid and hospitahty rendered me by the following gentlemen : In 1872, at Fort Bridger, Wyo., I was assisted by Capt. K. 0. Clift, in command of the post, and by Lieutenant Rogers, quartermaster, and Dr. Joseph Corson, surgeon ; also by Judge W. Carter and Dr. J. V. Carter. In Montana, in 1S7G, I received important aid from General E. 0. C. Ord, commanding the Department of the Missouri, and Major Ilges, in command at Fort Benton; and in my explorations in Washington Temtorj-, in 1879, I was under obligations to Dr. George H. Sternberg, U. S. A.* In 1880-81 the military authorities at Fort "Washakie, Wyo., rendered me much assist- ance, particularly Col. J. W. Mason, commanding, and Dr. W. H. Corbu- Bier, post surgeon.* I have received important aid from Professor Baird, of the Smithsonian Institution, and from Professor Condon, of Eugene City, Oreg. I wish here to place on record the names of my assistants, who have contributed greatly to the success of my expeditions, viz : William G. Shedd, Charles H. Sternberg, Jacob Boll, J. C. Isaac, Russell S. Hill, Frank Hazard, Jacob L. Wortman, and D. Baldwin. T have been also favored by special rates by the general officers of the Union and Central Pacific, and Pennsylvania Railroad companies. I wish here to express my thanks to Messrs. Kimball and Stebbins of the Union, and Governor Stanford of the Central Pacifies, and to Presidents Scott and Roberts of the Pennsylvania Railroad. The lithographic work of Messrs. T. Sinclair & Son maintains the well-known reputation of their house, and will prove satisfactory to students generally. I am, witli respect, E. D. COPE, Paleontologid, United States Geological Survey of the Territories. Dr. F. V. Hayden, Director of the United Stales Geological and Geographical Survey of the Territories. •In my explorations of foriiifttioim otlirr tliiin those treatwl of in tbi« volume, I have been assiated oy other gentlemen, gouoriiUy ollicers of the Army, to whom I will refer in the ft])]>n>i)riate place. PREFACE. 1. Sources of Collections. — The localities which yielded the fossils described in the following pages are the following : In 1872 I conducted an exploring party in Southwestern Wyoming. I left Fort Bridger July 19, and followed the road to Cottonwood Creek, southeast eighteen miles, whence we made our first excursions into the bad lands. After this our route laid along Cottonwood Ci'eek to Smith's Fork of Green River, thence along Black's Fork, and thence to Green River City. We then followed Bitter Creek to Black Buttes, and, leaving the line of the Union Pacific Railroad, ti-aveled south toward the headwaters of the Ver- million. Before reaching this point we explored the Mammoth Buttes, which form the water-shed between South Bitter Creek and Vermillion, and ex- amined the bad lands of the Washakie Ba.sin carefully. In reaching this point we crossed a portion of the Cretaceous formation, and I took especial pains to determine the relations of the strata at these points. We returned from this region and struck Green River seventeen miles above Green River City. We proceeded northward to the mouth of La- barge Creek, and, returning a short distance, ascended Fontanelle Creek to near its source in the outlying ranges of the Ham's Fork Mountains. The relation between the lake-deposits and the older strata here claimed special attention. We then descended Ham's Fork to the Union Pacific Railroad and returned to Fort Bridger. Special expeditions were made to the region round Evanston, and to Elko, Nev., with gratifying success. We obtained, in round numbers, one hundred species of vertebrated animals of the Eocene period, of which about sixty were new to science. We obtained material for the addition of two orders of mammals to those XXVI I'lIKFACE. previously represented in this fauna in the United States, viz, the Mcsodonta and Amhlypoda, the latter in several types of remarkable interest. In 1873 I fitted out an expedition at Greeley, Colo., and traversed the Plains eastward toward Julesburg as far as the eastern branches of the Cedar or Horse Tail Creek. Our route was parallel to the line of the so-called Chalk Bluffs, which extend from west to east, forming a break in the southern slope of the surface of the country from the dividing of the waters of the North and South Platte. It consists of the Loup Fork sandstones resting on a basis of the upper beds of the White River formation. The countr}- be- tween the foot of the bluffs and the South Platte River is composed in its northern part (if the White River tornialinii, Avl.icli jiresents exposures at various points, and neai-er the river consists of the Laramie formation. On this part of the expedition 1 obtained seventy-five species fnnn the White River beds, and twenty-one from the Loup Fork. We then turned to the southwest, crossing the South Platte, and moved up the valley of Bijou Creek towards the highlands of Colorado east of the mountains, known as the Colorado divide. On this part of the expedition, which was in charge of William G. Shedd, a number of interesting reptiles of the Laramie period were discovered. The party then entered the South Park and obtained a fine collection of the fishes of the Florissant shales During this time I had made an excursion to Fort Bridger, Wyo., and had supplemented the collections of the previous year. In 187 ^ I sent my assistant, J. C. Isaac, to Montana for the purpose of examining the valley of Deep River for the fossiliferous deposits previously reported to exist there by Captain Ludlow, United States Engineers, and examined by Messrs. Dana and Grinnell of his party. The results were satisfactory, a considerable number of fine specimens having been secured. Mr. Isaac then passed southeastward into W3'oming, and explored the White River beds of the southern parts of that Territory and the adjacent bor- ders of Wyoming. The same year I employed Charles II. Sternberg to conduct an explora- tion of the Cretaceous and Tertiary formations of Kansas. After a success- ful search I sent Mr. Sternberg to Oregon, and Russell S. Hill took charge of the expedition. Under his management an excellent collection of the PEEFACE. XXvii Mammalia and Reptilia of tlie Loup Fork formation of Northern Kansas was made, Mr. Hill discovering several new species of Mastodon, rhinoce- roses, tortoises, &c. The Tertiary formations explored in 1878 were the John Day, Loup Fork, and Equus beds, of Oregon. These were examined by Mr. C. H. Sternberg, who received important aid from his brother, Dr. George M. Sternberg, U. S. A. The John Day formation was chiefly examined on the John Day's River, and the Loup Fork beds at various points in the same region. These yielded about fifty species, many of them ]-epresented by specimens in an admirable state of preservation. The Equus beds were examined both in Washington and Oregon; in the former near to Fort Walla Walla, and in the latter in the desert east of the Sierra Nevada. The basin of an ancient lake, originally discovered by Governor Whit- aker, of Oregon, was found to be strewn with the bones of llamas, horses, elephants, sloths, and smaller mammals, with birds; and all were collected by Ml-. Sternberg and safely forwarded to Philadelphia. I examined this locality myself in 1879, and obtained further remains of extinct and recent species of mammalia found mingled with numerous worked flints. In 1879 Mr. J. L. Wortman took charge of m}^ party exploring in Oregon, and made extensive and valuable collections of the fossils of the John Day and Loup Fork beds of the eastern part of that State. In 1880 Mr. Wortman explored the deposits of the Idaho Pliocene lake of the Snake .River Valley, and made a valuable collection.* The same year he examined the Eocene beds of the Wind River Basin previously discovered by Dr. Hayden, and sent east forty-five species of vertebrata, of which twenty-four were new to science. In the following year Mr. Wortman pushed his explorations northwards, and discovered that the basin through which the lower part of the Big Horn River flows is filled with deposits of Wasatch Eocene age. These he examined for vertebrate . remains, and succeeded in obtaining sixty-five species, of which twenty- seven were previouslv unknown. Most important additions to our knowledge of the structure of various types were made, owing to the i-emarkably perfect condition of some of the specimens. •Proceedings Academy, Philadelphia, 1883, p. 153. XXVllI PREFACE. In 1881 I employed Mr. D. Baldwin to colk-tt fossils in the Puerco fomiation of New Mexico, which I discovered in 1874. Mr. Baldwin's suc- cess has had a very important bearing on the science of paleontology. He has obtained more than sixty species from that formation, iie:uly nil of wliirU were new to science. The expeditions have not been conducted without risks. My explora- tion in Western Kansas was made during a state of hostility of the Chey- enne Indians, and in a region where they were constantly committing mui- ders and depredations. During my expedition of 1872 I was abandoned by some of my party, who robbed me of mules and provisions, and placed me in some bodily peril. My expedition of 1873 was in the Cheyenne country, and constant vigilance was necessary. The year following my visit the whites were driven from the region, or murdered, by the Indians of that tribe. In 1876 I entered the Sioux country with my party on the Upper Missouri while the Indians were engaged with General Custer on the Little Big Horn and the Rosebud. My guide and camp tender abandoned me, and before leaving the country we passed a point a day's ride from Sitting Bull's camp on the Dry Fork of the Missouri. Mr. Sternberg's expedition of 1877 was interrupted by the Bannock war, and both himself and Mr. Wortman were compelled to leave their camp and outfit in the field and fly to a place of safety on their horses. In attempting to cross the Wind River in 1880 Mr. Wortman's horses and wagon were carried a\va\' li\ the current and the greater part of his baggage and provisions lost. Ilis exploration of 1881 was conducted under circumstances of nnuli risk from the absence of water. All the water necessary to the existence of his ani- mals and men had to be carried a distance of twenty miles on the backs of mules It is evident that an enthusiastic devotion to science has actuated these explorers of our western wilderness, financial considerations having been but a secondary inducement. And I wish to remark that the courage and regardlessness of physical comfort displayed liy thr gentlemen above refeired to in the pursuit of the idea of progress, are qualities of which their country may be proud, and are worthy of the highest commendation and of imitation in every field. PEEFACE. XXIX I have also received miscellaneous collections from G. W. Marnock, of Texas, from the late Tertiary formation of the southern part of that State, and from various persons in Nebraska, Dakota, &c. A few small collections received through the office of the United States Geological Survey of the Territories are mentioned in the proper places. 2. Mode of Preservation of Collections. — Since the value of deter- minations in vertebrate paleontology depends greatly on the condition of the collections, I give here some explanation of the methods I have employed in this direction. Prior to the publication of the descriptions of Elasmosaurus and various species of Pyfhonomorplia, from Kansas, in 1869-70, complete skeletons from the western deposits were unknown in eastern collections, or, if existing the fragments of different animals were so commingled as to be unavailable for purposes of determination. As it is self-evident that the science can make little progress without the discovery of entire skeletons, I have made every effort to secure them, commencing with my exploration of the Cre- taceous beds of Kansas in 1871. In the field entire skeletons are not rare, as' animals have often been entombed in soft deposits more or less uninjured. To obtain them in an entire condition, however, requires an unusual conjunction of circumstances The skeleton must be visible, but not so ftir exposed to the weather as to have suffered injurv from frost and rain, and it must not penetrate a hard matrix so deeply as to be inaccessible. As is the matrix, so is usually the fossil ; friable fossils belong to a soft rock, and hard ones to a hard rock. The exceptions to this rule are fossils found in dry sand, which are hard. In collecting, the first precaution to be observed, is to trace weathered fragments to their proper source in the adjacent deposit. This will of course be done, if at all, by following up the line of descent, either of escarpment or of water wash. If the remainder of the skeleton be found in place, the true correlation of the fragments will soon be discovered. The difficulty of extricating bones from the inatiix depends on the hardness or softness of the latter. The most favorable condition is an intermediate one, neither hard nor soft. The chalk of the Niobrara Cretaceous presents the most favorable conditions; next in order the matrix of the Bridger and ^ V V XXX PKEFACE. John Day formations preserves the bones best for extrication. The Wliite River formation of the Plains is only inferior in being a little softer, while the material of the Laramie formation varies between too great hardness or too great softness. The same difficulty, though in a less degree, is met with in the Loup Fork beds, softness predominating, while the least favorable of all for the preservation of fossils are the Puerco and Wasatch formations, where concretionar}' hardness prevails. In all of my expeditions great care has been exercised in preserving the relations in which the fossils have been found by placing marks on the same and by preserving notes and drawings made on the ground. These precautions are of course absolutely necessary to secure accuracy in the reference of the various fragments into which a skeleton is often broken. On the arrival of the collections in Philadelphia the labels on the packages insure their correct classification, and the work of reuniting the broken pieces commences. In many cases crania, bones, and skeletons having been taken out in a moi'e or less entire condition, inclosed in rock masses, much time is consumed in dressing them out with mallet and chisel. The amount of labor required for the preparation of the material of the present report alone, is easily seen to have been very great. I here refer to the skill of my assistant, Mr. Jacob Geisman, to whom the excellent character of this work is largely due. 3. Publication of Results. — The media of publication of the results of the investigations embraced in the present volume have been the fol- lowing : 1. Bulletin of the United States Geological and Geographical Survey of the Territories, F. V. Hayden in charge, Washington. 2. Annual Reports of the United States Geological and Geographical Survey of the Territories, Washington. 3. Proceedings of the American Philosophical Society, Philadelphia. 4. Proceedings of the Academy of Natural Sciences, Philadelphia. 5. Paleontological Bulletins. By E. D. Cope, Philadelphia. The last-named series consists in large part of rei)rints of papers which have appeared in the serials, Nos. 3 and 4; principally in No. 3. These reprints have averaged 200 copies each, but have sometimes amounted to PEEFACE. XXxi 300 copies ; in a few cases but 100 copies were issued. They have mostly- appeared in advance of the number of the serial which contains them, owing to the long intervals at which the latter were or are issued. Thus the Pro- ceedings of the American Philosophical Society were, up to a recent date, published but once in six months, and those of the Academy of Natural Sciences three times in the year. In some instances the Paleontological Bulletins have not appeared in any serial. In the earlier part of my inves- tigations the reading of the proofs of these and other papers was sometimes intrusted to other persons, owing to my absence from Philadelphia while conducting explorations. These persons at times allowed important typo- graphical errors to escape them, and in a few instances introduced alterations of the text, for which I wish to disclaim responsibility. This experience led me to avoid such confidence thereafter, so far as practicable. The literature of the Paleontology is given under the head of the separate divisions of the subject in which it appropriately falls. 4. Rules of Nomenclature. — I have adhered to the laAv of priority, as generally understood, in the use of names both in the biological and stratigraijhical aspects of the subject. I take this opportunity of noting what appears to have been at times forgotten by a few students of verte- brate paleontology — although fully recognized by biologists generally — that a name, unaccompanied by a definition or a precise reference to an existing definition, has no status in scientific nomenclature. A word so introduced is meaningless, and cannot be used, because that which it represents is unknown. Thus, names of classes and orders which refer only to popular definitions, such as "flesh-eaters," "insect-eaters," "whales," "worms," &c., have no scientific existence. These divisions of recent animals having been, however, by this time, well established by true analysis, the names pro- posed for extinct groups which are now being discovei'ed claim our attention.* The progress of paleontology has been retarded by the publi- cation of numerous names, supposed to refer to family and generic divisions, which are not accompanied by descriptions or by any statement of the reasons why their author has created them. Characters of the species desci'ibed *See Proceedings Americjm Pliilos. Society, 1873, p. 73. Report U. S. Geol. Survey Terrs., 4to, II, p. 113. Report of Lieut. G. M. Wheeler, U. S. Geogr. Surv. W. of 100 Mer., IV, Pt. II, p. 148. XXXll PREFACE. under the proposed generic name are usually given, and in some instances characters which really belong to the definition of the genus to which it belongs may be found mingled with them. In these cases it is left for the reader to discover these characters. Should he do so, he becomes the real discoverer of the genus, and as such is entitled to name it. The pub- lication of names in the manner objected to is, from every point of view, pernicious, and is very properlj' forbidden by well-known rules. It mat- ters not if it be ascertained at a subsequent date, and by some circumstan- tial evidence, what the author of such names referred to as to species and specimens. Such information cannot habilitate a nomen nudum ; nor is such circumstantial evidence accessible to students generally, especially to those who live at some distance from the locality whence it may be obtained. I now append the most important rules of nomenclature, as adopted by a majority — in most instances, a very large majority — of forty-five of the leading biologists of North America. They are included in the report of a Committee of the American Association for the Advancement of Science, appointed in 1876, of which Capt. W. S. Dall, U. S. N., was chairman.* 1. The reading of a paper before a scientific body does not constitute a publication of the descriptions or names of animals or plants contained therein. 2. A name applied to a group of species without a specification of any character possessed by them in connnon (that is, without any so-called generic diagnosis or description), is not entitled to recognition as an estab- lished generic name by subsequent authors. 3. A generic name applied to a single (then or previously) described species without a generic diagnosis or description of any kind, is not entitled to recognition as above, by subsequent authors. 4. A subsequent author shall not lie permitted in revising a composite genus (of which no type was specified when it was described) to name as its type a species not included by the original author of the genus in that latter author's list of sj)ecies given when the genus was originall} described. 5. \Yhen an old genus without a specified type has been subdivided by a subsequent author, and one of the old species is retained and specified * See American Naturalist, August, 1678. PEEFACE. - XXxiii to be the type of the restricted genus bearing the old name, it is not com- petent for a third author to discard this and select another of the original species as a type, when by so doing changes are necessitated in nomenclature. 6. When a generic name has lapsed from sufficient cause into synonymy, it need not be thenceforth entirely rejected from nomenclature, and may still be applicable to any new and valid genus. The earlier pages of this volume were printed between two and three years prior to the greater part of it, hence some of the earlier statements will be found to be modified in the more detailed discussions which follow. One such point is the distinction which should be maintained between the John Day and White River epochs; another point is the great distinction which should be recognized to exist between the Puerco and later Eocene periods. The faunae of the Puerco and Wasatch epochs are as diverse from each other as are those of the Bridger and White River. Some inequalities in the text, and the intercalation of numerous plates which carry letters attached to their numbers must be explained. These peculiarities are due to the fact that the discovery of the Puerco fauna was made after the first pages of the volume had been struck off, and the greater number of the plates had been numbered and printed. The present volume includes the vertebrata of the Eocene and of the Lower Miocene, less the Ungulata. There are described three hundred and forty-nine species, of which I have been the discoverer of all except thirty- two. They are referred to one hundred and twent3^-five genera. The most important results which have accrued to paleontology through the researches here set forth, are the following: (1.) The discovery of the Laramie genus Champsosaurus in Ter- tiary beds. (2.) The discovery of Plagiaulacidce, in Tertiary beds. (3.) The discovery of the characters of five families and many genera and species of the Creodonta. (4.) The discovery of the characters of the Periptychidoe and its included genera; and (5.) Of the Meniscotheriidce ; and (6.) Of the Phenacodontidce and its genera. Ill (; XXXI V PREFACE. (7.) The discovery of the characters of the suborder of Condylarthra and of the phylogenetic results of the same. (8.) The discovery of the characters of the Pantolambdidce ; and (9.) Of the suborder Taligrada and its implications in phylogeny. (10.) The discovery of the Anaptomorphidendic- g- ular walls constituted a great impediment to our prog- K ress. During- the days of my examination of the region '% heavy showers of rain fell, filling the arroyos with rush- § ing torrents, and displaying a peculiar character of this > marl when wet. It became slippery, resembling soap in g consistence, so that the hills were climbed with difficulty, - and on the levels the horses' feet sank at every step. The ^ material is so easily transported that the drainage chan- | nels are cut to a great depth, and the Puerco Eiver '•^ becomes the receptacle of great quantities of slimy look- S? ing mud. Its unctuous appearance resembles strongly ? soft soap, hence the name Puerco, greasy These soft § marls cover a belt of some miles in width, and continue at the foot of another line of sandstone bluffs, which bound the immediate valley of the Puerco to a point eighteen miles below Nacimiento. ,s'fnr.52, 7,I0U'. n "Anuual Report U. S. Geol. Surv. Terrs., 1875, p. 189. t Annual Report of Chief of Engineers, 1875, p. t Loc. cit, 247. Appendix L L. VERTEBRATA OF THE TERTIARY, ^^ T1m» PiitTco marls liavt- tlii-ir jiriiK-ipal devtloitnieut at this locality. I exam- ined them throughout the forty miles of outcrop which I observed for fossil re- mains, but succeeded in finding nothing but fossil wood. This is abundant in the region of the Galliuas, and includes silicilied fiagments of dicotyledonous and palm trees. On the Puerco, portions of trunks and limbs are strewn on the hills and ravines; in some localities the mass of fragments indicating the place where some large tree had broken up. At one point east of the river I found the stump of a dicotyledonous tree which measured 5 feet in ^ I > diameter. The fauna of this formation is diftereut from that of the other Eocenes in the presence of a saurian. Cha»ip80saun(.s. which is characteristic of the Laramie Cretaceous, and of marsupial Mammals {Ptilo- ^ ^ '^ 'liii and Catnjmilis) which are remnants of a type = -■ -fi known otherwise from the Jurassic. Characteristic x i -^ genera are Catathlceus, a many-toed omnivore, FnU- Z t = tacotherinm, a gnawing TiUodont, and various flesh- = ■? s eaters with primitive teeth. Coryphodon is, so far, " o ^ unknown. 3 '•^' a t K o 1:2 THE WASATCH. 2 3D o The Wasatch Group is the lowest of a series of "o v. I these fresh-water Tertiaiy groups, all of which are inti- c B"? mately connected, not only by an evident continuity of > >• o sedimentation throughout, but also by the passage of a "I •= H portion of the molluscan species from one group up into 2 ;^ I the next above. Not only were those three groups, = f i. aggregating more than a mile in thickness, evidently to £ ^ produced by uninterrupted sedimentation, but it seems ^ .| i e()ually evident that it was likewise uninterrui»ted lie- § I T tween the Laramie and Wasatch epochs, although there f J f was then a change from brackish to fresh waters, and "^ ^f a consetpient change of all the species of invertebrates 1 - J then inhabiting those waters. "■ I e In his annual rejtort for 1870, Dr. Ilayden pro- 2 S. posed the name *' Wasatch Group " for a series of strata " ''" that are extensively developed in Southern Wyoming J and adjacent parts of Utah and Colorado. I regard s the series of strata to which Mr. King lias given the ^ name "Vermilion Creek Group," and Professor Powell _■ that of "Bitter Creek Grouj)," as geologically equiva- lent with the Wasatch Grf)ui) of Dr. Ilayden, and 1 therefore use that name iu this report in accordance with tlie recognized rule iu such cases. WASATCH EPOCH. 7 The preceding remarks I have quoted from the report of Dr. C. A. White to Dr. Hayden,* as expressive of the position of this important for- mation. In hthological character, the Wasatch consists of a mixed arenaceo- calcareous marl, alternating with beds of white or rusty sandstone. The more massive beds of sandstone are in New Mexico, Colorado, and Wyo- ming, at the base of the formation. The mai-ls readily weather into the fantastic forms and canyon labyrinths of bad-land scenery. The marls often contain concretionary masses of a highly silicious limestone, which cover the banks and slopes of the bluffs with thousands of angular frag- ments. It is' characteristic of this formation that the marls contain brightly colored, usually red, strata ; and in many localities the colors are various, giving the escarpments a brilliantly banded appearance. Petrographically, this formation has two divisions, the Wasatch proper and the Green Eiver beds ; the latter name having sometimes been given to the entire formation as well as the former. Dr. White thus describes it:t Eesting immediately and conformably upon the Wasatch are the strata of the Green Eiver Group. Although intimately connected with the former by continuous sedimentation and specific identity of molluscan species, they differ considerably from those of that group in general aspect, and in composition also. The group is, Uthologi- cally, at least, separable into two divisions, but they are not regarded as severally of co-ordinate value with the other recognized Tertiary groups. The lower division consists mainly of silicious and sandy shales and laminated and thin-bedded sandstones, with, in some places, especially in the western part of this district, frequent layers of hard, dark-colored carbonaceous shales. In some places the strata are also quite calcareous, occasional layers being nearly pure, compact, finely-laminated limestone. Others of the calcareous layers are sometimes oolitic in textui-e. The general aspect of the strata, as seen exposed at a distance, is light gray. The upper division consists mainly of sandstones that are coarser, as well as less thinly and distinctly bedded, than those of the lower division. In some parts it is shaly and in others carbonaceous. Much of its sandstone is ferruginous in aspect, instead of having the gi'ay tint that the lower division has. Sometimes certain beds of its sandstones are eailhy aud easily disintegi-ated, often lea\dng, weathered out of the mass, spherical concretions of hard sandstone that vary in size from a fraction of an inch to two or three feet in diameter. Other beds sometimes present buttress-like masses in the brow of bluifs, which form conspicuous and somewhat remarkable fea- tures in the landscape. Such features are very characteristic of this division in the bluifs of Green Eiver, in the vicinity of Green Eiver City, Wyo., and, to a less extent, they also appear in the bluifs which border the canon and valley of White Eiver, in the southwest portion of this district. •Aiiuunl Report, 1876 (1H78), p. 35. t Annual Report U. S. Geol. Surv. Terrs., 1876 (1878), p. 35. 8 VEKTEBRATA OF THE TERTIARY. The invertebrate fossils which this group affords are similar to those that are found in the fresh-water portion of the Wasatch Group, some of the species being TTpper tarbaniferan* ^ri^?fr..fi*?r?^*. /s lYiiii'ii'iyil'ifTT Ti'i,i'ii!M'i,i'ii:i/(i /vi;i.' ■;i;i; z^:;^^;^^^^ Fio. 4. — General Beclion in tho Yniniia diHtrict. White in Annual Report United States Geological Survey Territories, 187G. i<1fntical, niid iiidicat*' a jmrcly frcsliwator ooiuHtioii tlironplumt. They are almost wholly iiutllnscaii, and belong to the branchitcroiiH genera Vnw,Vivij>aru«, and Gonio- WASATCH EPOCH. 9 basis, besides several genera of pulmonate gastropods, including both thelimnophile and geophile divisions. The Green Eiver Group has become somewhat noted for the fossil fishes that have been discovered in its strata in Wyoming, and, like the Wasatch Group, it has at various localities also furnished considerable collections of fossil vertebrates and plants. Of the few vertebrate fossils known from the Green River division, some are identical with those of the Wasatch, while at least one genus of fishes is common to the Bridger. The Wasatch beds proper are much more widely distributed than those of the Green River. They appear first in the south in Northwestern New Mexico, and extend thence into the adjacent parts of Colorado. They are exposed over extensive areas of Colorado west of the Rocky Mountains, and reappear in Southwestern Wyoming. They extend along the western portion of the Green River Valley, whose northern portion they entirely occupy. On the eastern side of the Wind River Mountains it has, accord- ing to Hayden, an exposure of from one to five miles in width for a distance of one hundred miles, from the source of the Wind River to the Sweet Water River. North of this point it fills the extensive basin of the Big Horn River to the borders of Montana. It does not occur east of the Rocky Mountain range. The thicknesses given by geologists are the following: Northwestern New Mexico (Cope). Feet. Ked-striped marls 1,500 Eeddishbrown sandstone 1,000 2,500 Bio San Juan, Colorado (Holmes). Coarse yellowish sandstones, alternating with variegated marls 1,200 White and Tampa Reservations (Endlich and White). Chiefly yellow and reddish sandstones, alternating with shales 1,600 Bear Eiver, Wyoming (Hayden). Eed-bauded marls 700 Sandstones and shales 800 1,500 Wind River Valley (Hayden). Variegated marls and sandstones 5,000 The Green River division of the Wasatch is much less extensively distributed than the Wasatch proper. Its exposures are confined to the 10 VEETEBRATA OF THE TERTIAEY. valley of Green River, particularly the regions between its atSuents both north and south of the Uinta Mountains. In the Bridger Basin it forms a ^Nnde rim around the Bridger formation, and is especially developed on Fontiinelle Creek, and on Bitter Creek, and the region to the south of it. I here found its thickness to be 1,200 feet.* Farther south, in Western Colo- rado, near the Yampa River, Dr. "White gives its depth at 1,400 feetf Farther south, in Western Colorado, Dr. A. C. PealeJ gives the united thickness of this formation and the Wasatch at 7,670 feet; but how much of this is to be refen-ed to the Green River proper we are not informed. It does not appear to exist on the San Juan, according to Endlich and Holmes, and I did not find it in New Mexico. According to King, the deposits of the Green River formation rest un conformably on those of the Wasatch. § He also believes that it has a considerable extent west of the Wasatch Mountains, over parts of Utah and Nevada. Under the head of the Bridger formation I show that the paleon- tological evidence is opposed to the identification of these "Amyzon" beds with the Green River, and that they are probably of later origin. There is, however, a series of calcareous and silico-calcareous beds in Central Utah, in Sevier and San Pete Counties, which contain the remains of differ- ent species of vertebrates from those which have been derived fi'om either the Green River or Amyzon beds. These are Crocodilus sp., Clastes sp., and a fish provisionally referred to Priscacara, under the name of P. testudinaria. There is nothing to determine to which of the Eocenes this formation should be referred, but it is tolerably ceiiain that it is to be distinguished from the Amyzon beds. In its petrographic characters it is most like the Green River. II The writer first refen-ed the Wasatch to the Eocene division of the Tertiary, it having been previously regarded as Miocene. (Proceedings American Philosophical Society, February, 1872.) The vertebrate fauna of the Wasatch is rich, and presents many pecu- • Annual H.port U. S. Gool. Snr\-., 18T3, pp. 436, 43!}. t Annual K.-port U. S. Gfol. Suit., 1870, p. 30. t Annual Ri-porl li^4, p. l."*. $U. S. SnrvfV of thr Foitipth Parallel, i, p. 377. II See American Naturnlist, April, lri@0. BRIDGEE EPOCH. 11 liarities. It is nearly identical with that of the Suessonian of Western Europe, which is at the base of the Eocene series. The fullest account of it is that which I have given in the Report of Captain Wheeler of Explora- tions and Surveys West of the 100th Meridian, vol. IV. THE BRIDGER. This is one of the more important of the groups among those that, in Western Iforth America, are referred to the Tertiary i^eriod, especially as regards the vertebrate remains that have been obtained from its strata. It is most fully and characteristicaUy developed in the region known as the Green River basia, north of the Uinta Mount- ains, only the southeastern portion of the formation, so far as it is now known, extend- ing into Northwestern Colorado. In its typical localities it is found resting conform- ably upon the Green Eiver Group, into which it passes without a distinct plane of demarkation among the strata. Irs molluscan fossil remains correspond closely with those of the Green River Group, some of the species being common to both, all indicating a purely fresh con- dition of the waters in which the strata of both groups were deposited. At the typical localities the group is composed in great part of soft, variegated, b^d-laud sandstones, a peculiar greenish color often predominating over the others, which are reddish, pur- ple, bluish, and gray. Limestone strata, marly and clayey beds, and cherty layers are not uncommon, and grits and gravelly layers sometimes occur. To the above general remarks of Dr. C. A. White I add, that the ma- terial of this formation consists of indurated clays more or less arenaceous, which display various degrees of hardness. The harder beds are, however, thin, and the intervening strata yield readily to meteoric influences. They are frequently quite arenaceous, and rather thin beds of conglomerate are not uncommon. The colors that predominate are greenish-gi-ay and brownish-green, with frequent ash-colored beds. The peculiar condition of hardness of most of the strata render it one of the formations which most generally present the bad-land scenery ; it permits the erosive action of the elements without general breaking down, great numbers of frag- ments of the strata remaining in spaces between the lines of erosive action. The result is the extraordinary scenery of Black's Fork, Church Buttes, and Mammoth Buttes, of which mention will be made in the section of this volume especially treating of the Bridger foimation. The distribution of the Bridger formation is limited, and is, so far as I am aware, restricted to three areas, whose mutual connection is as yet un- certain. Its principal mass is in the Bridger basin, which extends from the 12 VERTEBRATA OF THE TERTIARY. northern base of the Uinta Mountains to the latitude of the mouth of the Big Sandy River nortliward. In this area it reaches a depth, according- to King,* of 2,000 or 2,500 feet. A second district is also in Wyoming, and lies east of Green River between Bitter Creek and the northern boundary of Colorado, in what is called by King the Washakie basin. The depth of the formation there reaches 1,200 feetf The third region is in Western Colorado, where it loses much of its importance. Dr. C. A. White found it only 100 feet in thickness near the White River. J Dr. Peale found it near the Gunnison River, as he discovered vertebrae of Pap- pichthys, a genus which belongs to this horizon only ; but he did not dis- tinguish it from the underlying formations, so that I do not know its thick- ness at that point. South of this locality it is unknown. As already pointed out, this period is especially characterized by a peculiar and rich vertebrate fauna. THE XJINTA. Resting directly, but by unconformity of sequence, upon all the Tertiary and Cre- taceous groups in the region surrounding the eastern end of the Uinta ^lountaia range is another Tertiary group, that has received the name of " Uinta Group" from Mr. King, and "Brown's Park Group" from Major Powell. § It is possible that this group was deposited continuously, at least in part, with the Bridger Group, but at the places where the junction between the two groups has been seen in this region there is an evident unconformity, both by displacement and erosion. The group consists of fine and coarse sandstones, with frequent layers of gravel, and occasionally both cherty and calcareous layers occur. The sandstones are some- times firm and regularly bedded, and sometimes soft and partaking of the character of bad-land material. The color varies from gray to dull reddish-brown, the former pre- vailing north of the Uinta Mountains and the latter south of them. The only invertebrate fossils that are kuown to have been discovered in the strata of this group are some specimens of a Pliysa, very like a recent species. Therefore, invertebrate paleontologj' has fimiished no evidence of its assumed Tertiary age and lacustrine conditions of its deposition. Its fresh-water origin, however, seems unques- tionable, because of its intra-continental position, its limited extent, and the fact that none but freshwater deposits are known in this part of the continent that are of later date than the close of the Laramie period. To these remarks of Dr. White I add, that several species of vertebrata have been obtained from this formation by Professor Marsh, who has deter- • Gool. Explor. Fortiith Pnrallpl, ii, p. 245. t Aiiniml Hi-iiort U.S.Geol. Siirv. Ivm., 1873 (1874), pp. 436-437. I Anniiiil R<>port, 187(), p. :it). ♦ Anuoal Report U. 8. Geol. Siir>-. Terra., 1874, pp. 157, 158. WHITE EIVER EPOCH. 13 xnined from it a few genera of Tertiary and Upper Eocene character. Such are of Mesodonta, the genus Hyopsodus, and of Ungulata, the Perisso- dactyle form Amynodon. i THE WHITE RIVER. I The materials of t which the beds of this & formation are composed f in their eastern division, T are calcai-eous clays and ^ marls, alternating with a ? few unimportant strata ^ of light-colored sand- « stone. They are white i and gray, with occa- o- sionally a pink and red, g- and sometimes greenish S. tinges. The beds of the ? western deposit in Ore- i gon consist of a more ^ or less indurated mud, g which is, according to o King, of trachytic ori- a gin, which is rarely hard, 1 and frequently rather soft. Its predominating color is light green, but is frequently olive and light brown. The depth of the formation on the 14 VERTERRATA OF THE TERTIARY. White Kiver of Nebraska is, according to Hayden,* about 150 feet; and on Crow Creek, Colorado, according to King,t 300 feet. Sixty miles east of Crow Creek I estimate its thickness as somewhat greater. The Truckee beds of Oregon have, according to Marsh, a depth of from 3,000 to 4,000 feet, and King estimates the deposit exposed in the Hawsoh Mountains, Nevada, at 2,300 feet.J An extensive deposit exposed in the region of the Cajon Pass, Southern California, is suspected by King to belong to the same horizon. The followinjr section by Dr. Havden exhibits the strata of both this formation and the overlying Loup Fork epoch, as displayed on the White River, Nebraska. The bed marked E, and those above it, belong to the last-named formation. Sl'BDIVnSIONS. Localities. li .s-g 1^ g m g i 03 o u n Gr.ay and grceuish-gr.iv sandstone, varying from a very fine compact structure to a conglomerate. Bijon HiUs, Medicine Hills, Eagle Kest Hills. 9 d a Yellowish-gray grit, passing down into a yellow and light-yellow .argillo-calcareous marl, with nu- merous calcireons concretions and much crystalline material, like sulphate of baryta. Fossils: Hip- potherium, Protohippus, .Steneotiber, &c. Bijou Hills, Medicine Hills, Eagle Nest Hills, and numerous localitiesou south side of White River, also at the head of Teton River. 1 1^' Q (S n Grayish and light-gray rather coarse-grained sandstone, with much sulphate of alumina? dis- seminated throngh it. Along Wliite River Val- ley, on the south side. i 1 Yellowish and flesh-colored indurated argillo-cal- careous bed, with tough argillo-calcareons concre- tions, containing " Testudo, Hippotherium, Steneo- fiber, Oreodon. Rhinoceros," &c. Seen along the White River Valley, on the south side. 1 8 d Yellow and light-yellow calcareous marl, with argillo-calcareous concretions and slabs of silicious limestone, containing well-preserved fresh-water shells. On the south side of White River. Seen in its greatest thickncssatPinao's Spring. 1 o * Proceedings Academy Philada., 18.")", p. l-'iS. tReportof Geol. Survey of 40tli rarnllel, i, 410. JL. c, p. 423; 1. c., p. 415. WHITE EIVER EPOCH. 15 Subdivisions. Localities. |i II i t-H 8 Light-gray silicious grit, sometimes forming a compact fine-grained sandstone. Seen on both sides of White River. Also at Ash Grove Spring. A reddish flesh-colored argiUo- calcareous indu- rated material, passing down into a gray clay, con- taining concretionary sandstone, sometimes an ag- gregate of angular grains of quartz, underlaid by a flesh-colored argillo-calcareous indurated stratum, containing a profusion of mamm.ali.au and chelo- nian remains. Turtle and Oreodon bed. Revealed on both sides of White River and through- out the main body of the Bad L<>rt l.iriii. (;. M. Wbeolui-'n Kxplorations West of 100th Meridian, voLiv,p.283. tSec Uana'fi Manual of Ocology, eilit. 18(;4, p. 511. t Bull. U. 8. Geol. Surv. Toim, v, pp. 50-52. BQUUS BEDS. 19 The material of the Ticholeptus horizon is a more or less finable argil- laceous sand ; not so coarse and gritty as the Procamelus bed, nor so cal- careo-argillaceous as the White River. The Procamelus bed is extensively distributed. It is found in Kansas, Nebraska, Colorado, New Mexico, Utah, Nevada, and Oregon. THE EQUUS BEDS. I can give little information respecting the depth and stratigraphy of the beds of this period as they occur on the plains west of the Missis- sippi River, for although sections of them as they occur in Nebraska and elsewhere have doubtless been published by authors, their paleontological status has not been determined for the localities described. My own knowledge of the deposits is based on localities in California and Oregon. In Nebraska they have probably been confounded with the Loup Fork, beds. They represent the latest of all the Tertiary lakes, and include a fauna which consists of a mixture of extinct and living species, with a few extinct genera. • I have received fossils of this age from Idaho, Washington, Oregon, and California. The most important locality in Central Oregon is from thirty to forty miles east of Silver Lake.* The depth of the formation is unknown, but it is probably not great. It consists, first, of loose sand above, which is moved and piled into dunes by the wind; second, of a soft clay bed a few inches in thickness ; third, by a bed of sand of 1 or 2 feet in depth ; then a bed of clay mixed with sand of unknown depth. The middle bed of sand is fossiliferous. In Northern and Middle Califor- nia the formation is chiefly gravel, and reaches a depth in some localities of several hundred feet. Here, as has been proven by Whitney, it con- tains human remains, associated with Mastodon, Equus, Auchenia, etc. I have obtained Mylodon from the same gravel. Traces of this fauna are found over the eastern United States, and occur in deposits in the caverns excavated in the Lower Silurian and Car- boniferous limestones, wherever the conditions are suitable. This deposit is a red or orange calcareous mud, varied with strata of stalagmite and * See American Naturalist, 1878, p. 125. 20 VERTEBRATA OF THE TERTIARY. gypsum. Remains of the fauna are found in clay deposits along several of the Atlantic Rivers, as the Delaware and Potomac. It is probable that the formation in the western localities mentioned is mostly sand. Near Carson City, Nevada, it consists of a light-buff friable calcareous sandstone. This is the Upper Pliocene of King, and the Post-Pliocene of various ■writers. Fig. tki. — Sinid Hills Noitliwe.steru Ni braska i'rom Hayden. sectio:n" II. THE HORIZONTAL RELATIONS OF THE NORTH AMERICAN TERTIARIES WITH THOSE OF EUROPE. Uniformity of system requires that an identical scale of stratigraphy be employed by all geologists. In accomplishing this object, the students of distinct regions necessarily rely on paleontology as the guide in making determinations of the relations of strata, since determination by observation of continuity is impossible. The progress of the vertebrate paleontology in North America of late years has been such as to permit of comparisons with the extinct faunae of Europe and other continents, which give definiteness to our knowledge of the relations between their geologic periods. Comparisons made by Mor- ton and Leidy had nearly determined the position of some of the eastern Cretaceoiis strata, and those of Leidy had approximately fixed those of the White River beds. Lyell and Conrad early deteimined the positions of the Eastern Tertiaries. My own views as to the European equivalency of our Keuper* and Laramie f were first expressed, and I later established the ages of the Wasatch, J Bridger,|| Loup River,§ and PermianT[ formations in America. A more detailed comparison being very necessary, I visited Europe in 1878 for the purpose of examining the rich collections of verte- brate fossils, and read a general synopsis of results before the Congress of Geologists of Paris of that year. The present section embraces a summary of that paper, with some additional matter.** The history of the succession of life upon any one portion of the earth's surface is replete with matter for speculation. It shows us a series of faunte succeeding each other, each of which, in many instances, com- mences without previous announcement in the forms of older periods, and 'Proceedings Academy Pliila., 18CG, p. 249. t Report on U. S. Geol. Surv. Forticlh Parallel, iii, p — . Trausac. American Pliilosophical See. , xiv, 1869, pp. 40, 98, 243. t Proceedings Amer. Philos. Society, February, 1872. II Loc. cit., August, 1872. § Annual Report U. S. Geol. Surv. Terrs. , 187:!, p. 402 ; Proceed. Academy Phila. , 1875, p. 257. f American Naturalist, 1878, p. 327 ; Proceedings Amer. Philos. Society, 1878, p. 530. * * This synopsis was first published in the Bulletin U. S. Geol. Surv. Terrs., v, p. 33. See Comptes Rendus St^nographiques, Congrfes Internationale de Geologic 1880, p. 144. 22 VEETEBRATA OF THE TERTIARY. disappears without leaving representatives in later ones. With this basis of fact, which naturally enough has been furnished by the longest explored and best-known portion of the earth, Europe, we turn to other lands, with the hope of obtaining further light upon a subject so full of mystery. These types of life, did they originate in a single centre, from which they disseminated themselves; and, if so, did each form originate in a region of its own, or not? Or, did the same types of generic structure appear at diflferent points on the earth's surface independently ; and, if so, whether cotemporaneously or at different times ? For a solution of these and similar questions, we naturally look to a comparison of the facts first established, with those obtained more recently by exploration in other regions. In this quest, no portion of the earth offers greater promise of results than America. As the second great con- tinent, separated from the other by the greatest possible water surface, we anticipate the widest diversity in the character of its life-history. If the types of life have originated independently, we will find evidence of it by studying American paleontology ; if their origin has been through gradual modification, America should furnish us with many intermediate faunee. Let us first consider the nature of the evidence on which we should rely in classifying faunse and the deposits which contain them. We are accustomed, at present, to rely for our definitions upon all the faunal peculi- arities upon which we can seize: the period of appearance of certain types; the duration of certain types; and the disappearance of certain types, depending on orders, families, and genera for the major divisions, and species at a given locality for the lesser. It is, of course, evident that either of the above-mentioned three criteria are variable quantities, since discovery is constantly extending our knowledge of the distribution of types. Hence the definitions are empirical and temporary. We must, then, if we desire a stable system, examine the principles involved, and endeavor to discover definitions which stand on stronger foundations than those which we now possess. As a matter of fact, the old definitions of epochs and periods are con- tinually invalidated by new discoveries. As a matter of theory, this should be the case. DISCEIMINATION OF EPOCHS. 23 To the believers in the doctrine of derivation, the obliteration of faunal distinctions is not a cause of surprise. Such await with confidence the day when complete phylogenies will be possible, and at present regard the inter- ruptions in the succession of life as local only. Will the result then, be, that paleontology will cease to be available in the definition of ages and of deposits ? I answer no, on various grounds. Interruptions in the succes- sion of life in any given locality, due to various causes, have doubtless often occurred, and have left traces in the crust of the earth which are ineffaceable by discovery. But apart from this, one fact in this history is patent both to the friends and to the opponents of the doctrine of derivation: It is known that the world has witnessed, at every stage of its history, the extinc- tion of some important type of life. Familiar examples are the Placodermi of Paleozoic time, various reptilian groups of Mesozoic time, and the Amhly- poda of the Tertiary. Each minor subdivision of time ofi'ers its own record of persistences and extinctions of particular families and genera. Now, all departments of biology compel us to recognize the law of classification, that the order of forms is from the less to the more generahzed, from the simple to the more complex, and vice versa, whether the lines of succession be those of descent or of creative order ; and this law is true in time as well as in classification. It follows from this, that all types of life are, at the time of their appearance, less distinct and more general in their characters than they are later in their history. . It also follows, as a consequence of the principle of descent, which states that the types of one age have taken their origin from generalized types of preceding ages, that there is no descent from the most specialized types ; which is to say, conversely, that the genera, families, and orders whose extinction has been a marked feature of every geologic age have been the specialized types of those ages. We now have a clue to. a basis of a definition for faunae, and hence for epochs, which discovery can safely build upon. The successive increments of structure by which an important modification of animal type is intro- duced, preclude the possibility of exact determination of the time at which such type may be said to have appeared. Even where such a point may be arbitrarily fixed, the type must then be less characteristically represented 24 VERTEBRATA OF THE TERTIARY. than it is at the other Hmit of its existence, viz, the period of its disappear- ance. For these reasons I must regard tlie latter criterion as the true one in the discrimination of the subdivisions of geologic time, while the point of the appearance of types must be looked upon as of provisional use only, and this quite independently of the changes which discovery will from time to time compel us to make in our knowledge of the distribution of life in time and space. It must, however, be borne in mind that disappearance may be due to two causes : first, to extinction ; and secondly, to modifica- tion ; a distinction which is entirely essential. The case of disappearance by modification is identical with that of appearance by modification, and cannot be used otherwise in classification. It is, then, the period of extinc- tion of types to which I have reference. With these principles in view, we attempt the comparison of the ex- tinct faunae of Europe and North America, employing principally the nomenclature of D'Orbigny for the former, and Hayden for the latter, in the Mesozoic and Tertiary series. It is well known that no remains of Vertebrata have yet been discovered in North America in strata of Silurian age, while several species are known from the Upper Silurian of Europe. The latter are Placodermi and sharks, and are not very numerous in species. They have been derived from England, Gennany, and Russia. In America, the first fishes appear in the Comiferous limestone at the base of the Devonian. Professor Newberry, who has devoted much attention to this department, points out important distinctions as existing between the Devonian fish faunae of North America and Europe, and also to important coincidences. The first of these is the occurrence of the genus Macropetalichthys in both continents; in Germany in the Eifel limestone, and in America in the Corniferous limestone of Ohio. The other examples are furnished by the Catskill beds of New York and Pennsylvania, which contain a part of the fauna of the old Red Sandstone of Scotland, including the genera Holoptychius and Bothriolepis* The structure of the Batrachia of the Coal-Measures is not yet suffi- ciently well known to enable the most exact comparisous to be made, but • Oeological Survey of Ohio, i, pp. 264, 271. PALiEOZOIC AND MESOZOIC. 25 close parallels, if not identities, of genera exist. Such are the OesfocepJialus and Ceraterpeton of Ohio as compared with the Urocordylus and Ceraterpeton of Great Britain. The Permian vertebrate faima which I discovered in Illinois and Texas exhibits close parallels, but not yet generic identity, in the two continents. Thus, the American Clepsydrops and Dimetrodon are near to the Beutero- saurus of Penn, in Russia, and the Lycosaurus of the mountains of South Africa. The Texan genus Parioticlms may, with further information, prove to be identical with Procolophon Ow. from the Tafelberg. Humeri of the type discovered by Kutorga in Russia, and by Owen in South Africa, are found in North America, and the same remarkable type has been recently discovered by Gaudry in France. The peculiar type of Ganocephalous vertebrae described by me under the genus Rhachitomus from Texas, has been discovered by Gaudry in France. The even more remarkable Cricotus (Cope), type of the Emholomera, is paralleled by the Biplovertehron (Fritsch) of Bohemia. Edosteorhachis represents in Texas the genus Ilegalichthys. The present indications are that close similarity between the faunae of this period in Europe and America will be discovered. Nevertheless, up to the present time no representatives of the striking American forms Bolosaurus, Diadectes, and Empedocles have yet been found in any other continent. As regards the Triassic fauna, it differs from that of the Permian in being better known in Europe than America. As marine Trias is little devel- oped in North America, so the vertebrate fauna of the Muschelkalk has not been discovered in the latter country. It is otherwise with the Keuper. The characteristic genus of that epoch, Belodon, existed in America, and parallels, if not identity, are seen in the genera Thecodontosaurus and Palceosaurus. These are known in America from teeth only. The reptiles are accompa- nied in North America, as in Europe, by Stegocephalous BatracJiia, mostly Labyrinthodonts, but their generic affinities are yet unknown. The great Jurassic fauna^. are as yet but sparsely represented in North American paleontology. The marine Vertebrata of the Lias are either unknown or are represented by a few provisional identifications of unsatis- factory fragments. "We do not yet know any deposits in North America which contain the typical reptilian genera Plesiosaurus, Ichthyosaurus, Plio- 26 VERTEBRATA OF THE TERTIARY. saurus and Dimorphodon, or the fishes of the Dapediidce. This formation, 80 important in Europe, is almost omitted from the North American series. Several characteristic fossils of the Rocky Mountain region represent the Oolite, particularly the Upper Oolite. Such is a genus not yet distinguisli- able from Megalosaurus. This genus has not been identified beyond doubt from above the Oolite in England. Teleosaurus and Steneosaurus, and their allies, are not yet known from North American beds. From the same beds in the Rocky Mountain region come genera which nearly resemble the one from the English Oolite (Forest Marble) called by Phillips Cetiosauriis, and the genus from the Oxfordian of Honfleur, called by von Meyer Streptospondylus. Beyond this no comparisons can be made, and we therefore pass to the rich fauna of the Kimmeridge. North America cannot show such records of this epoch as have been found in Europe There are no Archceoptenjx, Bhamphorhynchus, nor Pterodactylu^-^; no Leptolepis, Thrissops, nor other of the numerous fishes of Solenhofen. The Omosaurus has, however, some very close relatives in the Camara' saurus beds of the Rocky Mountains. Remains of the primitive Mar- supial fauna which occurs in the Purbeck have been recently detected in the Western Continent. A partial representation of the Wealden fauna of Europe is found in the beds of the Rocky Mountains mingled with the types of the Oolite and Kimmeridge already mentioned. The important genus Camarasaurus represents the Ornithopsis of Europe, and with Amphi- codias included the most gigantic of land animals. The relationships of this fauna to those of the European Jurassic series may be thus exhib- ited: American. Kiiroiiciin. Camarasaurus Beds. "Wealden. f Iguanodon. f Ilypsilophodon. Hypsilophodon. Hijlceosauriis. t Cettosaurus. Cetiosaurus. Camarasaurus. Ornithopsis* Amphica'lias. fGoniopholis. GoniopJwlis. 'CJumdrotttotaurut Owen. MESOZOIO. 27 American. European. KiMMERIDGE. HypsirJiophus. Omosaurus. Caulodon. f Caulodon.* Oxford. Epanterias. Streptospondylus. Oolite. " Cetiosaurus." ? Megalosaurus. Megalosaurus. From the above table it will be seen how difficult it is to parallelize the related beds of the Jurassic periods of the two continents at the present time. All that can be said is, that many types resemblingf nearly those of different horizons of the European Jurassic are found to have lived together or near together in the Rocky Mountain region of North America. That the Cretaceous fauna of North America was the richest in the cold-blooded Vertehrata is indicated by the present state of discovery. The ocean of the interior of the continent deepened from the beginning of the period until the epoch of the Niobrara, and then gradually shallowed until the elevations of the bottom began to divide the waters. The closing scenes of this great period were enacted amid a labyrinth of lagoons and lakes of brackish and fresh water, whose deposits form the beds of the Laramie epoch. The fauna of the deep-sea epoch, the Niobrara, is the best known. Here the i-emains of Pythonomorpha constitute its prevailing characteristic, while Elasmosaurus and Polycotylus, with but few species, represent the numerous Sauropterygia of Europe. Crocodiles were apparently wanting, while turtles and a peculiar group of Pterosauria were only moderately abundant. The fish fauna was very rich and varied. Here the Saurodon- tidcB, like the molluscous family of the Eudistes, appeared and as soon dis- * Iguanodon prcecursor Sauv. t A near affinity has been shown by Professor Owen to exist between Eucamerotus and Camarasau- rut. Profegaor Owen believes these genera to be identical ; bnt the neoral spines of the anterior dorsal vertebra are very different, being single in the former and doable in the latter. 28 TERTEBEATA OF THE TERTIARY. appeared, accompanied by the peculiar form Erisichthe, and the family of StratodontidfB. The genera of Mount Lebanon, Leptotrachehts and Spanio- don, occur in this bed in Dakota ; but the closest parallelism is exhibited with the Lower Chalk or Turonian of Western Europe. The general fades of the reptilian fauna is that of the Lower Chalk, and there is little doubt that several genera are identical in the two continents, e. g. Elasmosauru^. The apparent peculiarity of the Chalk in America is the abundance of forms (four genera) of Fi/lhonomorpha, with numerous species, while but two genera have yet been found in Europe, and the presence of birds with biconcave vertebrae and teeth. This interesting type, which was first dis- covered by Seeley in the genus named by him Enaliornis, and afterwards found by Marsh to possess teeth, has been found at a lower horizon in England, the Upper Greensand. But in England, France, and Westphalia occur the genera of fishes above mentioned, as Portheus, Ichthyodectes, Saic- rodon, Saurocephalus, Erisichthe, Empo, Pachyrhizodus, Enchodus, Leptotra- chelus, etc. This close relationship of the horizons permits an identifica- tion, and it is the first instance which appears to me to be susceptible of satisfactory demonstration. The next horizon of the Cretaceous which has yielded many verte- brate remains in North America is the Fox Hills formation (including the Fort Pierre bed). Here the genus Mosasaurus appears in America, and is accompanied by the earliest crocodiles with procoelous vertebrae, and by numerous marine turtles which partake of the characters of both CMydri- d(B and Cheloniida, which I have called the Propleuridce. Beryx appears first here in America. The predominant genus of fishes is Enchodus, and the principal Dinosauna are Lcdaps and Hadrosaurus. This horizon has been ])arallelized with the Maestricht of Europe, and several genera are common to the two beds ; such are Mosasaiirus and Enchodus. The genus Hadro- saurus, and the family of turtles I have called the Adocida, remain undis- covered in Europe ; hence the identity of faunaj cannot be established. The lacustrine beds, or summit of the American Cretaceous series, the Laramie of Hayden, present the remains of a populous fauna and a rich flora. The students of the palneobotany have declared this flora to be of Eocene, and the later portions of Miocene, character, while tlie lacustrine MESOZOIC. 29 constitution of the strata has influenced the stratigraphic geologists to con- cur in the view that the formation should be arranged with the Tertiary epochs. That the fauna was of a mixed character is the result of a study of its vertebrate fossils. The predominant type in North America was the Dinosauria, which were abundant in species and individuals, and this fact alone will suffice most paleontologists as a reason for referring the epoch to the Cretaceous series. The genera of Dinosauria (Palcsoscincm, Ciono- don, Diclonius, Monocloniiis, Bysganus, etc) have not yet been found in any other part of the world. Mingled with them were species of crocodiles and turtles of indifferent character, while a number of other forms existed which had a limited range in time, and hence are important indicators of stratigraphic position. Such are the genera of fishes, MyledaijJius Cope and Clastes Cope, which have been found also near Reims, France, by Dr. Lemoine, in the Sables de Bracheux, which are regarded as the lowest Ter- tiary. Such is the curious Saurian type Champsosaurus (Cope) {Simcedo- saurus Gerv.), and the turtle genus Compseniys Leidy, which Lemoine finds a little higher up in the series, in the conglomerate of Cerny, which is in the lower part of the Suessonian. In France, a genus of the Laramie, Polythorax, extends into the Lignite or Upper Gorypliodon bed of the Sues- sonian Thus the Laramie is intercalated by its characters between the Cretaceous period on the one hand and the Tertiary on the other, and its fauna includes genera and orders of both great series. These relations may be exhibited in tabular form as follows. I here include the faunae of the Sables de Bracheux and of the conglomerate of Cerny as one, since both possess the types of the Laramie, while the horizon of the Lignite of Meudon, or the Suessonian, does not. Sables de Bracheux and Con- Laramie. GLOMERAT DE CeRNY. a. Teetiaey. Lophiochosrus. Plesiadapis. Pleuraspidotherium. Arctocyon. Clastes. Clastes. 30 VERTEBRATA OF THE TERTIAEY. y?. Peculiar. Champsosaurus. Compsemys. Myhdaphus. Sables de Bracheux and Con- GLOMEEAT DE CeENY. Champsosaurus. Compsemys. Myledaphus. Scapherpeton. Laeamie. y. Ceetaceous. Pakeoscincus. Dysganus. Monoclonius. Diclonius. Cionodon. Lcelaps. Auhhjsodon. If the Conglomerate of Cemy be the same horizon as the Conglomerate of Meudon, we must add Coryphodon to the upper left-hand column, and probably Gastornis also. The i*esult is clear that the French and American formations together bridge most completely the interval between the Cre- taceous and Tertiary series, as has been anticipated by Hayden, in America, on geological grounds. It is also evident that another formation must be added to the series already recognized in France, viz, the Laramie or Post- Cretaceous. Tliis will be defined as the beds of the genera Champsosaurus and Myhdaphus. In France, the presence of mammalia will characterize the formation as a subdivision, for which it is probable that the name Thanetian must be retained ; while to the American division, which is characterized by tlie presence of Dinosatiria, the name of Laramie beds has been given. In arranging the Laramie Group, its necessary position is between Tertiary and Cretaceous, but on the Cretaceous side of the boundary, if we retain tliose grand divisions, which it appears to me to be desirable to do. The reasons for retaining it in the Cretaceous are two, viz: (1) because EOCENE. 31 Dinosauria are a Mesozic type, not known elsewhere from the Tertiary; (2) because Mammalia (should they be found in the future in the Fort Union) are not equal as evidence of Tertiary age, since they have been also found in Jurassic and Triassic beds. The Eocene fauna is so varied, especially in Europe, that it is neces- sary to compare the divisions separately, as in the case of the Cretaceous. Thus, the fauna of the Suessonian is quite as distinct from that of the Cal- caire Grossier and Gypse (Parisian and Tongrian) in France as are those of the Wasatch and Bridger epochs in North America. I have already identified the Wasatch with the Suessonian or Orthro- cene, on account of the community of the following genera in the two continents: Coryphodon, Hyracotherium, Amhly clonus, Clastes, and a form of birds close to Gastornis. I can now add Phenacodus, Orotherium (Cope), and very probably Hyopsodus, Adapis, Opisthotomus, and Prototomus. But, as above mentioned, in the lower beds of the Suessonian in France occur genera which are, so far as yet known, wanting in the Wasatch of America, but present in the beds of the Laramie. The parallelism of the American Wasatch with the Upper Suessonian of France is the second identification which may be regarded as provision- ally established. The only important discordant element at present known is the Tceniodonta of the Wasatch, which have not so far been found in Europe. Above the Suessonian, a divergence in the characters of the European and North American faunae commences, and continues to be marked through- out the remainder of Tertiary time. So far as the Mammalia are concerned, the diversity between the continents was greater during the periods of the Upper Eocene and Miocene than at the present era. During these periods, a limited number of genera, common to the two continents, was associated with numerous genera in the one which did not exist in the other. As a consequence, our paleontological means of identification of the horizons are limited to a restricted list, and the task of applying a uniform nomencla- ture is, under the circumstances, diflScult. Another difficulty in the way of determining the place of the American beds in the Eui-opean scale consists in the fact that the physical history of the two continents dui'ing the Ter- 32 VERTEBRATA OF THE TERTIARY. raiy period appears to have been different. In America, the changes of evel appear to liave been more uniform in character over large areas. Each deposit has a wider geographical extent, and the fauna presents less rregular variation. In Europe we have a great number of comparatively estricted deposits, each of wliich differs from the others in possessing more or less peculiarity of fauna. After a study of these faunae, their natural arrangement in Europe into three series — Eocene, Miocene, and Pliocene — does not appear to rest on any solid basis. This is especially true of the distinction between the first two; and authors are at variance as to the point of demarkation between the last two. Thus, the Tongrian is the summit of the Eocene according to Renevier, while Gaudry, with Filhol and others, places it at the base of the Miocene. One opinion is as well supported by facts, as now interpreted, as the other. As an essential aid in the estimation of the Hmits of the formations, I appeal to the criterion adopted at the opening of this chapter, viz, the period of extinction of animal groups. If we take a general view of the Tertiary faun£E, we find that the fol- lowing well-marked types representing famiUes and higher groups have become extinct, and have left no living descendants or successors : Among Bunotheria, the American groups Tceniodonta and Tillodonta ; also the Meso- donta of both continents; of Edentata, Macrotherium, and Ancyhtherium in Europe, and the 3IegatJieriidce in North America; among the Carnivora, the Eyanodons and Proviverrce, with the Drepanodons ; of Ungidata, the entire order of Amhlypoda, which, however, doubtless disappeared in some of its members by modification ; but its only known suborders, the Pantodonta and the Dinocerata, become absolutely extinct. Among Perissodactyla, both continents lost by extinction the ChaUcotheriidcB, which terminated in a great development in North America; and the Bhinocerida. Of Artiodactyla, two great divisions, representative of each other in the two continents, totally disappeared, viz, the OreodontidcB and the Anoplotheriida ; to which must be added the Hyopotamidfc. Of true ruminants, the most important type which has disappeared from both continents is that of the Cameltda, Oi 8u\\\hw gauera, Anthracotherium and Elotherium may be looked upon as EOCENE. 33 having left no persistent successors. Last of all, the Proboscidea retreated to the continents of the south. In view of the complexity of the European record, I first present the relations of the above-mentioned phenomena as displayed in the simpler American system. As the present essay commences with the earliest periods, I exhibit the succession in descending order on the page. The horizons of the Tertiary which present distinct terrestrial faunae in North America have been named the Wasatch, the Bridger, the Uinta, the White River, the Loup Fork, the Equus beds, and the Champlain. The types which became extinct* with the close of each of these epochs are the fol- lowing : Wasatch. White Rivek. Gastornithidae. Leptictidce. Pantodonta. Hycenodon. Bridger. Ghalicotheriidee. BaenidcE. Hyopotamidce. Tillodonta. Loup River. Stypolophuis. Mhinoceridce. Dinocerata. Hippotherium. Uinta. Oreodontida. fMesodonta. Equus Beds. Amynodon. Megatheriidee. Drepanadon. Tapiridce. Elephas. CamelidcB. The above table exhibits the present state of our knowledge ; it will doubtless be much extended by future discovery, but not otherwise modified. The numerous able writers on European vertebrate palaeontology have more frequently recorded the appearance of types in defining their faunal • This means, as already mentioned, the forms which left no direct snccessoTs in the Nearctio and and Palasarctic faunae. 3 C 34 VERTEBRATA OP THE TERTIARY. divisions than their disappearance. The follo\ving table is compiled from the writings of Gervais, Gaudry, Pomel, Filhol, Renevier, and others, but is not as complete as I would desire. SUESSONIAN. FaLUNIAN. Pantodonta. Anchitherium. Parisian (Bruxellian, Bartonian, Anthracotherium. and Sestian). Paheochcerus. Pal(eoj)his (Bruxellian). Ccenotherium. Proviverra. Oeningian. Pterodon. AncyJotherium. Mesodonta. Dinotherium. Lophiodon (Bruxellian). Hippotherium. ToNGRiAN. Aceratherium. PakEotheridce. Subapennine. Chalicotherinm. Mastodon. Anoplotheridce. Tapirida. JSlotherium. Diluvial. Aquitanian. Hycena. Hycenodon. JDrepmiodon. Hyopotamus. Elephas. Ehinocerus. Hippopotamus. The above tables show that the history of mammalian life in the two continents presents many points of resemblance ; but that there is a great difficulty in coirelating the epochs represented by the known faunjE. As regards the two primary divisions, Eocene and Miocene, they have no special raison d'etre, as such faunae as the Tongrian and Oeningian are absolutely transitional in their character. More detailed comparisons of the European and American faunae bring out many relationships not displayed by the above tables, and which I will now briefly consider. In the American Bridger, various genera of Mesodonta represent the few Adapidae of the Parisian, the genus Adapts* Cuv. being probably com- mon to the two continents. A near ally of the American Anaptomorphus, a * A'otharctut i» undiatingaiBhuble from Adapis in inferior dontal cboracttini. EOCENE. 35 true Lemur, has been found by M. Filhol in tlie Phosphorites, and named Necrolemur. The characters of the numerous Carnivora of the Bridger are as yet unknown. The Stypolophus of the Bridger is perhaps the Pro- totomus of the Wasatch, and this again has been discovered by M. Filhol* in France ; while a very similar genus has been discovered in the Swiss Siderolitic, and named Proviverra. Hyanodontidce probably occur in the Bridger. Nowhere in Europe do we find the Dinocerata and Tillodonta of the Bridger. Palceosyops is also unknown in Europe, but it plays the part in America of the Palceotherium,, from which it does not greatly differ in structure. The latter genus is most largely developed in the Parisian, but is also characteristic of the Tongrian. Hyrachyus is the American Lophi- odon, the difference between them being but slight; both are found in France ; the former in the Lower Parisian, the latter in the Phosphorites. Tapirulusf Gerv. is a genus common to the Bridger and to more than one horizon of the Parisian. The squirrel-like rodents of the Bridger are like those of the Parisian, but they are not confined to either epoch. The char- acter which distinguishes the Parisian most widely from the Bridger, besides the absence of the Dinocerata and Tillodonta, is the presence of numerous Selenodont Artiodactyla, as Xiphodon, Ccenotherium, Amphimeryx, Anoploiherium, etc. These are of primitive type, it is true ; the Anoplothe- riida especially having probably four toes in the very short manus {Eury- therium), including the poUex, and three behind. They also display the character of a fifth crescent of the superior molars, which is wanting in the higher Selenodont types. But even these genera are absent from the Bridger. The ensemble is then that the latter displays relationships back- wards, or to the Suessonian, while the Parisian has a later fades, consti- tuting an approach to the Tongrian and White River. J The following table presents the relations of the Bridger fauna suc- cinctly, but it is much less complete than we hope to make it when its numerous species are fully described. The Parisian is here regarded as including the divisions Bruxellian, Bartonian, and Sestian (Gypse). * It is described as Cynohijcenodcm with two species. tGervais, IHoO ; Helaletes Marsh, 1872, vide Scott, Spier, and Osborne. t See Ann. Kept. U. S. Geol. Snrv. Terrs. 1873, pp. 461-462, where this view is proposed. 36 VERTEBKATA OF THE TERTIARY. Parisian. Didelphys. Vespertilionida. Plesiardomys. HycEnodontidcB. Adapis. Necrohmur (Phosph). Bridger. f Didelphys. VespertilionidfP. Plesiardomys. Tillodonta. HycBnodontidcB. Adapis. f Ui.Tr«iwU>j Anaptomorphvs. Dinocerata. PalcEosyops. Palceotherium. Lophiodon. Hyrachyus (Phosph.). Hyrachyu-s. Tapirulus. Tapirulus. Anfhracotherium. Achcenodon. Chceropotamus. Dichohune. Anoplotherinm. Xiphodon. Amphimeryx. The rich Tongrian (Stanipian) fauna is, according to authors, repre- sented in the Sables de Fontainebleau, Pay en Velay, Ronzon, Hempstead, and Cadibona in Italy. We find here Didelphys in abundance, Hyanodon, Amphicyon, Canis, Palceotherium, Paloplotheriuni, Oialicotherium, and Ace- ratherium. Of Artiodadyla, the Suillines are Anthracotherium and Elothe- rium; the Selenodonts, Hyopotamus and Gelocus. This list is the nearest known counterpart of that of the fauna of the White River epoch of North America. To reproduce the latter we must omit from the above catalogue the genera of Palccotheriidoe, and replace them by the allied Clialicotheroid Menodus and Symhorodon, subtract Anthracotherium, and add the great body of the Orcodontida: Then there are included in the White River fauna the higher Selenodont Artiodactyles of the Poehrotheriidw and Hypertragulida^, the corresponding types of which belong to the fauna of St Gerand le Puy in France, or the Aquitanian epoch, which directly succeeded the Stam- pian. In Europe, we have here Dremotherium, Amphitragnlus, Lophiomeryx, MIOCENE. 37 Dorcatherium ; in America, Leptomeryx, Hypertragulus, Hypisodus, and Poe- brotherium. It is curious that while Leptotneryx is also European,* it has not yet been found above the Phosphorites. Among Suillines, the Paloeo- chcerus\ of the Oregon White River beds has also not been found below the Aquitanian in Europe. But the American DidelphysX Hywnodon, Amplii- cyoti, Elotherium, and Hyopotamus, with the numerous Chalicotheroid species, show clearly that the White River fauna may be looked upon as a mixture of those of the Stampian and Aquitanian, the former of which is sometimes referred with reason to the Upper Eocene, while the latter is always left in the lowest Miocene. And the solution of this question of position as regards the White River beds appears to me to be at present by no means €asy.§ According to the system of Naumann, it should be called Oligocene. Although Artiodactyles with Selenodont molars are far more abundant in both continents during this period than the last, a remarkable difference is to be observed between them. Those of Europe still largely consist of the types with five crescents, as represented by the numerous Hyopotami and Ccenotheria, while in America the modern fom*-crescent-bearing molar characterizes almost the entire suborder, the only exception being two species of Hyopotamus. The following table will represent the relations of the White River fauna: Stampian and Aquitanian. White River. Didelphys. Didelphys. Leptictidce. ProtomyidcB Protomyid(B.\\ Saccomyidce.^ Stampian and Aquitanian. White River. Steneofiber. Steneofiber. Leporidce. Leporidce. * I think M. Filhol's Prodremoiherium is identical Trith Leptomeryx. t Tkinohyus Marsh appears to be the same, t Herpetotherium Cope ; Peratherium Aym. J See Ann. Report U. S. Geol. Surv. Terrs. 1878, p. 462, where the White River beds are deter- inined as Lower Miocene. II Ischyromya Leidy. IT Enioptychua and FlearoUeus Cope. / 38 VERTEBRATA OF THE TERTIARY. Stampian and Aquitanian. Hycenodon. Amphicyon. Cants. Giilo.* Pro(elurus. Adurogale (Phosp.). PaleeotheriidcB. Aceratherium. JElotherium. Paleeochoerus. Anthracotherium. Anophtlieriidce. HyopotamidtE. Lophiomeryx. Amphitragidus. Leptomeryx (Phosph.). Dremotheritim. White River. Hyanodon. Amphicyon. Cants. Temnocyon. Enhydrocyon. Gulo.* Archalurtis. Nimravus. Dinictis. Hoplophoneus. Chalicotheriida. Hyracodon. Aceratherium. Anchitherium. Elothcriwn. PalcBochoerus. Oreodontidce. Hyopotamidce . Poebrotherium. Hypertragulus, Leptomeryx. Hypisodus. The Falunian epoch includes in the large sense the Langhian, HeWe- tian, and Tortonian divisions, embracing the rich deposits of the Orlcanais, of Simorre, and of Sansan. We have here the true Miocene fauna, of wliich the following genera are characteristic: Edentata, Macrotherium ; Probo- scidea, Dinotheriitm, Ma.stodon; Perissodactyla, Anchitherium, IJstriodon; * Amphiclin Pom. t Copi! 1H74 ; /VoecrruJun. Oaiidry, 1878; Dicrooeriu Copo, 1874 (uot Lurtot) ; Merycodut et CotoTj/z Leidy, nomina nudn. MIOCENE. 39 Artiodactyla, Palceomeryx, Bicrocerus, Cosoryx;\ Carnivora, AmpMcyon, Hyeenarctos, Brepanodon ; Quadrumana, Pliopithecus. The ancient genera Anthracotherium and Ccenotherium continue throughout, and the existing genera Arvicola, Lutra, and Sus appear. The succeeding epoch, the Oenin- gian, including with it the horizons of Epplesheim and Pikermi, presents the additional genera Borcatherium, Helladotherium, several genera allied to Antilope, with Hippotherium, the huge edentate Ancylotherium, and the monkey Mesopithecus. It is from these materials that we must determine by comparison the American Loup Fork epoch, whose deposits are widely spread, and whose fauna is of well-marked character. Although called by my predecessors Pliocene in age, I have insisted that it should be referred to the Miocene series, and I think that the evidence to that effect which I have produced will be found conclusive. Nevertheless here, as in other American Ter- tiary horizons, the element of geographical peculiarity enters, and diminishes the number of identical types. Falunian. Steneofiber. Macrotherium. Ancylotherium. Amphicyon. Binotherium. TetralopJiodon. Aceratherium. Anchitherium. Listriodon. Hippotherium (Oeningian). Ccenotherium. Anthracotherium. Palceomeryx. Bicrocerus. Loup Fork. Steneofiber. Mylagaulus. Morotherium. Amphicyon.* Gcenobasileus. Tetralophodon. Aphelops. Hippotherium. Protohippus. Hipjndium.f Oreodontidce. Blastomeryx. • CanU ursinua Cope. t PUoMppus Marsh. 40 VERTEBRATA OF THE TERTIARY. Falunian. Loup Fork. Cosorijx. Cosoryx. Protolahis. Procamelus. The existing genera mentioned as found in the Falunian fauna are paralleled by the Dicotyles, Hystrix, and Mustela of the Loup Fork beds. It is e\'ident that this latter horizon retains in its Oreodontidce the same traces of antiquity that the Falunian does in its Ccenotherium, but shows a more modem aspect in the omission of Anchitherium and its replacement by Hippotherium and ProtoMppus, and in the still more modern type Hippidium. Although but six genera of the two continents are determined as identical in the above table, yet others, which are facing on the same line, are very nearly allied. Other differences are geographical. The facies of the Loup Fork horizon is then a compound of that of the Falunian and Oeningian, or Middle and Upper Miocene. In commenting on the above-described fauna in 1874,* I remarked that "the proper discrimination of the American Pliocene remains to be accom- plished." It was not long after that date that material for making the identification of this horizon on this continent first came into my hands. This was derived from the superior Tertiary of Oregon, and includes a con- siderable number of species of fishes, birds, and Mammalia. I published a list of some of the species in 1878.t The character of the fauna from that region coincides with that which has from time to time been unearthed in the caves and other Eastern deposits, to such an extent, as to lead us to suspect that the differences between them are geographical only. In Em*ope the Pliocene, or Subapennine, includes, according to D'Orbigny (1855) and Gaudry (1878), the Plaisancian and Astian, which are represented at the following localities : Subapennine. PlaUancian. — Montpellier; Casino (Tuscany). Antian. — Perrier, near Issoir, Ooiipet, Vialette (Upper Loire), Chagny; English Orag; part of deposits of the Val il'Arno. Tlie characteristic of this fauna is the fact that the species belong • Report Lient. G. M. Wheeler, iv, Paleontology of New Mexico, 1874, p. 364. fBuU. Hayden'8 U. 8. Geol. Snrv. Terra, iv, 187ti, p. 389. EQUIVALENCY OF BEDS. 41 mostly to existing genera, the chief exception being Hippotherium. The horses are chiefly represented by Equus. Common genera are Ardomys, Lepns, Elephas, Mastodon, Tapirus, Sus, Cervus, Antilope, Bos, Canis, Drepa- nodon, Felis, Ursus. In the Equus beds of Oregon a few extinct genera in like manner share the field with various recent ones, while not a few of the bones are not distinguishable from those of recent species. I give the fol- lowing list, the extinct species being in italics : Mylodon sodalis. Canis latrans. Thomomys (nr.) clusius. Elephas primigenius. Equus occidentalis. Equus major. Auchenia hesterna. Auchenia magna. Auchenia vitakeriana. Cervus fortis. Thomomys talpoides. Castor fiber. l/utra near piscinaria. The species derived from the cave formations of the Eastern States are more numerous, and diflfer from the Oregon fauna in many respects ; yet the parallelism is close in the genera with the Equus beds on the one hand and the Pliocene of Europe and South America on the other. The differences distinguishing it from the Equus beds of Oregon are, however, such as compel me to regard it as a distinct division of the Pliocene, under the name of the Megalonyx beds.* Megatherium (p). Mylodon (p). Megalonyx (p). Sciurus (s). Arctomys (s). Jaculus (s). Arvicola (s). Erethizon. Hydrochcsnis (p). Castoroides. Lagomys (s). Lepus (s). Anomodon. Scalops. Arctotherium (p). Procyon. Canis (sp). DrepanodonSmilodon (vel). Mastodon (sp). Equus (sp). ? Hippotherium (s). Tapirus (s). Dicotyles (p), Cariacus (p). Bos (s). Mustela (sp). In the above list the extinct genera are marked in italics. There exists, as a marked feature of the North American Pliocene, to which I called attention several years ago,t a considerable representation of the fauna of *BuU. U. S. GeoL Surv. Terrs, v, p. 5a, 1879. \ ProcAoad. PhUa. 1857, 156; Proc. Am. Philos. Soc. 1869, 178. 42 VERTEBRATA OF TDE TERTIARY. the Pampean formation of South America; such are twelve genera, of which six are extinct genera, and four are pecuHar to that formation and fauna. The genera found in the Pampean are marked (p), and those of the Subapennine (s). In the list from the Oregon localities, Mylodon and Auchenia were observed to be the only distinctively Pampean genera. As a conclusion of the comparison of the American Equus beds in general with those of Europe, it may be stated that the number of identical gen- era is so large, that we may not hesitate to parallelize them as stratigraph- ically the same. On the other hand, the agreement with the South Ameri- can Pampean formation is so marked in some respects as to induce us to believe that the distinction is geographic rather than stratigraphic. Believ- ing that the Pampean formation contains too large a percentage of extinct genera to be properly regarded, as it has been, as Post-Pliocene or Quater- nary, its characters, both essentially and as a result of the comparison which I have been able to make, refer it properly to the Pliocene. It appears, then, that the term Pliocene or Subapennine is appHcable to the horizon of this fauna in Europe and North and South America. RESUME OF COMPARISONS. The conclusions to be derived from the facts enumerated in the pre- ceding pages are as follows: I. Portions of all the faunae of all the primary divisions of geologic time have been recognized on both the European and North American con- tinents. II. Parallels requiring general identification of principal divisions of these faunaj may be detected. These are: the Coal Measures; the Per- mian; the Laramie; the Maestri chtian; the Eocene; the Miocene. III. Exact identifications of restricted divisions maj' be made in a few instances only; such are the Turonian and the Niobrara; the Snessonian and the Wasatch; the Equus beds and the Pliocene. It is not impossible that some of the relations mentioned in II will be by the accession of further information, referrible to the list of exact com- parisons in III. In iill cases of identification it will be necessary to employ the name first proposed with definition for the horizon, other names taking KOMECLATUEE OF FORMATIONS. 43 places as synonymes But in the majority of strata it will be necessary to preserve the special names : thus those of Bear River, Bridger, White River, and Loup Fork, applicable to beds having no exact equivalents in Europe, cannot be set aside for older ones, but must themselves be applied to cor- responding faunal horizons elsewhere, should any such be found in future. And it will rarely happen that the minor subdivisions of such faunae will be found to have an extent sufficient to warrant their having other than special names. In the accompanying diagram the series of strata of Europe and North America, as determined by their paleontology, are placed side by side for the purpose of comparison. Complete parallelism can only be predicated of divisions of the first order, separated by horizontal lines. Such relation is indicated by exact opposition of the areas representing the epochs in question. In giving the minor divisions of the European epochs I have generally restricted myself to those of the epochs which have American equivalents. Where there is no equivalent on one side or the other, the vacancy is represented by a diagonal Hne. In employing names for epochs and their divisions, I have adhered to the law of priority as far as my knowl- edge of the literature allows.* I have given a few names to American for- mations, but only in instances where such had not been previously given. In such cases I have pieferred employing the name of some characteristic genus of fossils, rather than one of local origin. COMPARISON WITH THE SCALE DERIVED FROM PALEOBOTANY. I now consider another kind of relation presented by the American and European horizons. I allude to the florae, for my knowledge of which I am necessarily dependent on the labors of others. I first exhibit the deter- minations of the ages of the American formations, already discussed, made by Mr. Lesquereux on the basis of the vegetable remains which they contain. I place by the side of these my own determinations of the ages of the same beds, as already related. The former are derived from the full memoir of Mr. Lesquereux in the Annual Report of the United States Geological Sur- * In the European system I have been much aided by the writings of Woodward, Gervais, H6bert, Pomel, Gaudry, etc., and by the atlas of Professor Renevier, of Lausanne. 44 VERTEBKATA OF THE TERTIARY. vey of the Ten-itories for 1872, pp. 410-417. It will be observed that there is a constant discrepancy between the two tables. Losqucrenx. Formation. 1 Cope. Loup Fork . Miocene. White River Oligocene. Upper Miocene Miocene Lower Eocene j Wasatch » ( Green Hi vcr J Lower Eocene. Upper Cretaceous. It" the determinations of Mr. Lesquereux be correct,* it is evident from the above that the vegetable life of North America reached its present condition one epoch or period earlier than the higher Vertebrata, and that the nomenclature is thus thrown back by so much It would appear that the recent flora of North America is a period older than the fauna, i. e., has persisted longer than the latter by a certain length of geologic time. Applying the same reasoning to the past, I embodied the idea in reference to the Laramie period ("Fort Union") in the statement that "a Cretaceous fauna was then contemporary with a Tertiary flora" ;t and, later, that "an Eocene fauna was contemporary with a ^Miocene flora." It may have to be added that a Miocene fauna was contemporary with a Pliocene flora. Since Mr. Lesquereux has the support of the best paleobotonists of Europe in his conclusions, it is useless to take the ground assumed by a few of my colleagues, that the former gentleman has simply erred in his determina- tions. He gives us grounds for believing that he has not done so, by giving us the European standard by which his identifications are governed.^ It is as follows : Pliocene .. Miocene .. Oligocene . Eocene ... Paleocone. Lower limits not positively fixed; largely developed in Italy, t (Subapennine, E.D.C.) Ocningian; Mayencian; Aquitanian. Tongrian. Gypso of Aix ; Alum Bay ; Mt. Bolca ; London Clay ; Sheppey ; Oris of the Sarthe. Upper Landcnian; Sezanne (=:Panisclian). Sueawnian (Lignitio Soissonais; Sables de Bracbeux); Lower Landenian. Horsian; Gelindon. ^Limestone of Mens, overlying nnconformably the Maestriohtion. • The above parallels are well presented by Dr. Pealo in his report to Dr. Haydcn, Ann. Kept. U. 8. Geol. Surv. Terra. 1S7J, p. Ill ct tcq. t Bulletin U. S. Ocol. Surv. Terra. I, art. 2. p. 16, April, 1S74 (Ann. Beport U. 8. Geol. Surv. Terrs. Ib74, p.aS5. PEIMITIVE CHARACTERS. 45 This system, it will be observed, is almost exactly identical with that employed in the preceding pages as the standard of comparison for the Vertebrata. Yet it has resulted, from a most careful comparison of both faunae and florae of America with this standard scale, that two distinct paleontological series have to be adopted, the one for the vertebrate life and the other for the plants, of the Western Continent. If this result be accurate, and there appears to be no avoiding it, an explanation must be sought. There are only two possible ones ; either the animal life of North America has lagged behind that of Europe by one period during past geo- logic time ; or, secondly, the vegetable life of America has been equally in advance of that of Europe during the same period. In other words, if the plant-life of the continents was contemporaneous, ancient types of animals remained a period longer in North America than in Erope. If animal life was contemporaneous, plant-life had advanced by one period in Europe beyond that which it had attained in North America. In any case, either the faunal or the floral standard of estimation of geologic age of strata for North America is a false one, since there can be but one standard of com- parison for anything. But this great fact being understood, the evidence of each of the great departments of life possesses its own intrinsic value. In conclusion, it may be observed that the lacunae in the series as pre- sented by one continent, render us dependent on the other for the evidence necessary for the complete elucidation of the laws of the creation of animal life. Phylogenies can be thus constructed which would otherwise be impos- sible, and the results of researches into the earliest types of Vertebrata become intelligible. Thus I have been able to prove, in support of a thesis published in 1874, that the earliest Ungulate Mammalia were pentadactyle and plantigrade. I have also shown that the ankle-joint had not, in the primitive Mammalia, the hinge-like character that it has in the later ones, but that it is without the interlocking superior articulation. The small size of the brain of early Mammalia, already pointed out by Lartet, has received extensive confirmation by the researches of Marsh, who has also shown the progressive increase in size of the whole body in various mammalian lines. To these results I have added another, which is derived from the study of numerous Permian Vertebrata, viz, that the earliest land vertebrates had a persistent chorda dorsalis. PART FIRST. THE PUERCO, WASATCH, AND BRIDGER FAUNA 47 P^RT FIRST. THE WASATCH AND BRIDGER FAUN^. PISCES. The remains of fishes are abundant in the lacustrine Eocene forma- tions of the United States, and several principal groups are represented. These pertain to the Elasmohrancld and the Hyopomata ; Dipnoi and Holoce- phali are unknown. Of Hyopomatous fishes, indications of the Crossop- terygia and the Chondrostei have not yet been found, but of the third group, the Actinopteri, we have several distinct orders, commencing with the more generalized Ginglymodi and ending with the specialized Percomorphi. The facies of the Eocene fish fauna is that of the existing fresh waters of the United States, exclusive of the great order of the Plectospondyli (unless the Amyzon beds are Eocene), and with the addition of two families, Osteoglos- sidee and Chromididee (aff*.), at present confined to the southern hemisphere. ELA8M0BRANCHL XIPHOTRYGON Cope. American Naturalist, 1879, p. 333. Family Trygonidce; that is, the tail furnished with a seiTate spine and the pectoral fins united in front of the rostral cartilage. Teeth closely placed in a few rows, the crowns developed into a triangular cusp, which is directed backwards, as in Raja. Pelvic arch without anteriorly directed inferior processes. No superficial ossification of the rostral cartilage. No caudal fins observed. This genus is Trygon, with the teeth of Raja. It further differs strik- 4 0 49 50 TUE WASATCH AXl; iiUlDGEK FAUNiE. ingly from tlie typical Tnjgones in the form of the caudal spines. These are trigonal in section, ami l)ear a ventral keel, and a serrate edge on each side. The extinct species of the Monte Bolca Eocene, Trygon muricata, has, according to Gazzola, the spine of the true Trygones. XlPHOTRYGON ACUTIDENS CopC. American Naturalist, May, 1879 (April). Plato I, figs. 1-5. This species is of graceful proportions, having no great transverse expansion, and possessing a long and slender tail. The size is inferior to that of a fully-grown skate, but much exceeds that of the Cyclohatis oligo- dactylus of the Lebanon. The ossification of the superficial part of the cranial cartilage is wide, extending to the branchial fissures below. It terminates anteriorly, in a sliglitly concave truncation, a short distance in front of the orbital open- ings. Two convex lobes immediately behind the mouth, divided by a median fissure, resemble the labial flaps. They are marked by rather larger hexagons than the other surface. The least hexagons form a longi- tudinal oval patch on the middle line behind these flaps, which corresponds in position to the superior fontanelle. Posterior to the scapular arch the ossification forms a band on each side of the vertebral column, and, gradu- ally narrowing, disappears near the origin of the caudal spines. The proptervgia extend well forward, giving outline to an acute snout. They are segmented to the extremity. The outline of the fin expands gradually from this apex. The metapterygial border is very stout, and is not so long as the propterygial. The posterior border of the pectoral fin does not extend quite so far posteriorly as the posterior border of the ven- tral fin. The latter, in turn, extends for about three-fourths the length of the claspers from the base of the fin. Pectoral rays; metapterygial, 31; mcsopterygial, 10; propterygiiil, 41. The vertebra^ are fully ossified; the caudal series becomes very slender distally, and measures nearly twice as long as from the pehac arch to the anterior border of the cephalic ossification. In the specimen described there are three caudal spines situated near together, whose origins are a ELASMOBEANCHI. 51 little posterior to the middle of the length of the caudal series of vertebrae. They are all depressed at the base and triangular in section beyond, and have an acute ventral edge. The lateral edges are finely and rather remotely serrate, the serration being obsolete on the smallest or anterior spine. In all, the infero-lateral faces of the spine form a shallow groove, like that of a bayonet. These spines are very different from those of the Trygons of the American and European seas, where they are depressed, oval in section, and have the teeth on each side much more closely placed. The teeth of this species are small. Viewed from below, those of the upper jaw form a very few series of triangles, with their bases approxi- mated and their acute apices directed backwards. Their bases are of differ- ent form, and are expanded and probably bifurcate, as several sections or anterior views of teeth are preserved, which exhibit two divergent roots and a flat summit. The functional surfaces of the triangular crowns are flat. The greater number of the segments of the fin-rays are shown by the sections to have been hollow cylinders, with a fibrous axis Measurements. M. Total length (entire) 515 Total width at middle of abdomen 230 Length of head (without muzzle) to scapular arch above 100 Length of abdomen to pehdo arch 064 Length of tail 351 Length to origin of spine ICO Length of spine 040 Depth of spine 003 Width of base of muzzle .' 023 Width between propterygia (greatest) 060 Width between metapterygia (greatest) '. 065 Width of pelvic arch iu front - 043 This species is so far known to me from a single specimen. This was obtained from Twin Creek, in the Bear River region of Southwestern Wyoming, by Leslie A. Lee, of Bowdoin College, Maine, who very liber- ally placed it at my disposal for study and description. Its presence in the Green River shales, adds to the evidence offered by other anadromous types of fishes, in favor of the view that the Green River Lake had commvinication with the ocean. The first information as to the existence of rays in the Green River formation was furnished by Professor Marsh, who obtained a specimen from 52 Tnr. wasatch and BRrooER faun^. Twin Creek. He gave .a meager description of the species, but quite neg- lected to describe the genus, on which account its affinities remain unknown. The presence of several tubercles mentioned by Marsh indicates that it is a different species at least from the Xiphotryyon acutidens. GINGLYMODL Cope, Proceedings American Association for tbe Advancement of Science, 1H71, p. 330. Physostomous Actinopteri, with a praecoracoid arch and a coronoid bone of the mandible. Vertebral centra opisthocoelous. Parietal bones in contact ; pterotic and opisthotic bones absent ; pectoral fin with mesoptery- gium and five other basal elements This order contains as yet but one family, the Lepklosteklce, which em- braces three genera, the recent Litliolepis and Lepidosteus, and the extinct Clastes. The existing species, as is well known, are confined to the rivers and lakes of North America, while the extinct forms occur in both Europe and North Ameiica. The earliest appearance of this type in geological history yet known was in the Laramie or Upper Cretaceous epoch in North America. Individuals of one species, Clastes occidentalis Leidy, were very numerous at that period. During the Wasatch or Suessonian in North America, they were equally abundant, and I have described two species from this honzon in New Mexico. Species and individuals are plentiful in the Bridger beds, as indicated in the following pages, but in the various tracts of the White River epoch they are absolutely wanting.* Tliey do not occur in the Loup River deposits east of the Rocky Mountains, and only reappear in the interior of the Continent in the present period. On the other hand, the family is represented in the marine Miocene beds of the Atlantic seaboard by the genus Pneumatosteus Cope, of which a single speciesf has been foimd in North Carolina In Europe tlie Lepidosteidce make their appearance at nearly the same horizon as in America, Lemoine having obtained Clastes from the lowest Suessonian (Chalons-Sur-Vesle), and Gervais having determined it from the Upper Suessonian. * ProcecdiniKS Aiiu'rican Pliiloso]iliiciil Socioty, 1877, p. 9. t Proceedings Americau I'bilusoiiliical Society, 1669, p. 242. GINGLYMODI. 53 CLASTES Cope. Annual Report U. S. Geol. Surv. Terrs., 1872 (187.3), p. 633. American Naturalist, 1878, p. 761. Mandibular ramus, without or with reduced fissure of the dental for- amen, and without the groove continuous with it found in Lepidosteus. One series of large teeth, with small ones exterior to them in the dentary bone, the inner superior aspect of that bone without prominent dentiferous or rugose rib. An inspection of French specimens, probably belonging to this genus, has shown that the maxillary bone is much less segmented than in Lepidos- teus, if it be divided at all. The characters o£ Clastes were originally derived from the under jaw, and I have observed them in two species, one which I suppose to be the Lepidostens gldber Marsh, and the other L. atrox Leidy. Tlie species of this genus resemble in many ways the Lepidostei of the present day. Their scales are rhombic and pierced by a duct on the lateral line. The cranial bones are ornamented by tubercles of ganoine, distrib- uted variously, according to the species. Some of these fishes reached a large size, exceeding any now living, othei's resemble the true Lepidostei in this respect. The first indication of the occurrence of gars in our Western Tertiaries was furnished by Professor Marsh, who announced his discovery of them before the Academy of Philadelphia (Proceedings 1871, p. 105). He named two species, but did not give any descriptions, excepting so far as the statement that one of them has "unusually short vertebrae," and that the other has them " proportionally longer," maybe regarded as such. Under these circumstances I have been unable to identify the species referred to, and think that the names proposed for them by Marsh cannot be used. Clastes anax Cope. Annual Eeport U. S. Geol. Sui-v. Terrs., 1872 (1873), p. 633. Plate II, figs. 50-52. Represented by some cranial bones and especially by a post-temporal, which indicate a very large species of gar, two or three times as large as the alligator gar of the Mississippi, (Litholepis ferox). The bone has a 54 THE WASATCH AND RRIDGER FAUX^^. free, ovate posterior outline, and its superior surface is covered with a thick layer of dense bone, which has not the brilliant surface of ganoine. This substance is thrown into elevated, coiTugated ridges, which are generally transverse to the long axis of the bone, and inosculate and are interrupted frequently. The spaces between are as wide as the bases of the ridges. Measurements. u. Width of bone 042 Thickness of bone 012 Found in the Bridger bad lands of Ham's Fork, Wyoming. Clastes atrox Leidy. Cope, Annual Report U. S. Geol. Surv. Terrs., 634, 1872 (1873). Lepidosteus atrox Leidy, Proc. Acad. Nat. Sci. Phila., 1873,97. — Report U. S. Geol. Snrv. Terw., i, 1873, p. 189, PI. x.\xii, tigs. 14-15. Abundant, and represented by both rough and smooth scales, the former from the anterior part of the body. As this species has been already described by Leidy, I only refer to my Plate II, figs. 1-24. Clastes cyclifeeus Cope. Annual Report; U. S. Geol. Surv. Terra., 1872 (1873), p. 634. Plate II, figs. 25-45. Established on numerous remains of a small species, in which the scales are rather wide, and generally with obtuse extremital angles, and frequently in certain regions of the body entirely rounded at the posterior border. Fragments of the cranial bones are ornamented with scattered tubercles of ganoine of rounded form, and not distributed in lines as in some species. In a fragment from the posterior part of the mandible, there is a single row of large teeth, with a series of minute ones between them on the outer edge of the bone. The external face presents a smooth, superior surface, and a rugose inferior portion which is marked by irregular lines of points of ganoine. Measuremeiits, M. Depth of dentary bone WCO Width of above 00,\5 L<'iiKt)i of a Hcalc (exposed face) OOGO Width of a scale (exposed face) OOtX) From the Mammoth Buttes, Washakie Basin. GDfGLTMODI. 55 Clastes cuneatus Cope. Proceedings American Philosophical Society, 1877, p. 9; (name only). Plate I, fig. 6. This gar is represented by numerous specimens from the Manti Shales of Central Utah, some of which are preserved almost entii-e. None of them exceed a foot in length. I describe the best specimen accessible to me, a small one, kindly lent me through Dr. Hayden by Mr. Bai-foot, director of the museum of Salt Lake City. The proportions are rather stout, and the base of the ventral fin is a little nearer the base of the tail than the end of the snout. The head is not perfectly preserved, but its outline, as clearly defined on the slab of limestone, is wedge-shaped, not longer than in Lepidosteus platystomus, but narrower. This view is, however, partly profile. The posterior and infe- rior borders of the operculum form a continuous segment of a circle, and the depth of the suboperculum is .66 the horizontal width of the opercu- lum. The preoperculum is superficially divided by transverse grooves into four scuta, of which the superior is the largest ; they are ornamented with small tubercles of ganoine. All the other bones, includirig the frontals, present radiating lines of the tubercles which are capped with ganoine, excepting on the operculum and suboperculum, where they form scarcely interrupted ridges. The scales are smooth, even near the scapular arch, and are arranged in eighteen or nineteen longitudinal series, as seen in an oblique row directed obliquely upward from the ventral fin. Fulcra of the ventral fin rather long and slender. The region of the dorsal fin is some- what disturbed; the fin is in any case situated very far posteriorly; anal and extremity of caudal fins wanting. Measurements. M. Axial length from end of mnzzle to base of caudal fin 215 Axial length from end of muzzle to base of dorsal fin 182 Axial length from end of muzzle to base of central fin 125 Axial length from end of muzzle to edge of operculum 063 Length of skull to preopercular border .049 Depth of skuU at preopercular border 036 Depth of body at ventral fin 050 56 THE WASATCH AND BRIDGER FAUN^. This species differs from some of those of the Bridger formation in the smoothness of the scales on the anterior part of the body. It is a smaller species than most of those of both that formation and the Wasatch. The characteristic vertebrie are e.xhibited by various specimens. HALECOMORPHL PAPPICHTHYS Cope. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 634. Family Ami'uJce. Vertebrae short, the abdominal with prominent dia- pophyses, and with each neurapophysis articulating with two centi'a; sides of the centrum not pitted. Maxillary bone supporting a single series of teeth and with a supplementary bone on its distal upper border. Dentary bone deeply grooved on the inner side and with but one series of teeth. Surface of cranial bones sculptured. This genus differs from the existing Amia in the presence of only one series of teeth instead of several, on the bones about the mouth. The ver- tebral centra possess a smaller anteroposterior diameter and relatively greater transverse diameter in the anterior part of the column ; but the value of these characters is not yet certainly understood. The maxillary bone overlaps the premaxillary extensively by its proxi- mal extremity, and presents no condylar facets (P. pUcatus). The sym- physis of the dentaries is not sutural. The condyle of the inferior quadrate is rough (P. leevis, P.plicatus). Its posterior grooves show the position of a symplectic ; while the inferior anterior portion shows a coarse sutural ser- rate junction with the ectopterygoid (in the above species). The centra of the vertebrae are most transverse anteriorly; in the posterior abdominal region they become subround; in the anterior caudal region, higher than wide; and in the greater part of the notocaudal region are subround They all have a minute notochordal performation. The neurapophysial facets of the anterior and posterior positions are distinct in the anterior abdominal ver- tebrae, and confluent on the caudals of all the species; the point at which they become confluent is different in the different species. On a few ante- rior abdominal centra the inferior surface is entire, or displays a slight depression; soon two parallel fissures, one on each side of the median line, HALECOMOEPHI. 57 appear, which become oblong fossae. These continue until they become naiTOwed again, anterior to the caudal senes. In the latter they are as well developed as the neurapophysial pits and are much like them. Several species of this genus have been found in the Bridger forma- tion in "Wyoming and Colorado, but it does not occur in the Wasatch. While some of them were first reported by Marsh, who referred them to Amia, they were first described by Leidy (Report U. S Geol. Surv. 4to Tol, I., p. 184, Plate xxxviii). One generic and one subgeneric names were used by Dr. Leidy in this connection, but without diagnoses. Among the specimens at my disposal I have found but one genus, to which I gave the name now used, with a characteristic diagnosis This genus is the earliest known representative of the order Haleco- morpM, which consists at present of but two genera; the present one and Amia. The latter first appears in America in the ? Eocene Amyzon shales of Florissant in the South Park of Colorado, where two species have been found; A. seutata Cope, and A. reticulata Cope.* Pappichthys first occurs in the Bridger formation, and constitutes one of the faunal distinc- tions between that epoch and the Wasatch, which immediately preceded it. However, it occurs in the Wind River beds, mixed with Wasatch Mammals. In Europe this genus is found at lower horizons than in America, having "been discovered by Dr. Lemoinef near Reims, in the Suessonian conglomer- ate, which answers partly to the lowest Wasatch and partly to the Upper Laramie epochs. Pappichthys sclerops Cope. Annual Report U. S. Geol. Surv. Terrs., 1672 (1873), p. 635. Plate III, fig. 1. Established on a ramus of the mandible of one, and other similar specimens of other individuals. These indicate a large fish, equal in size to the alligator gar of the Mississippi. The dentary bone is more compressed and deeper than in P. plicatus. The longitudinal groove runs above the mid- dle line, and the poition of the bone below it thins to an edge. The upper portion is thickened, and the alveolar border is wide and bounded by an angle * Se« Bulletin of tbe U. S. Geol. Surv. Terrs , 1875, p. 1. t Kecherclics s. 1. Oiseaux Foss. Tert. Infer, des En v. Reims, 1378, p. 65. 58 THE WASATCH AND lUMDGER FAUN^,. on the inner side. The alveoli are large and shallow; in .t»25 m. scarcely three find place. Near the symphysis is a smaller one \\ hit li is separated by a considerable diastema from the succeeding one (perhaps abnormally). The external face of the bone is rough and somewhat tubercular. Measurements. M. Duptli iif (Irntary at Byin|ih,v8iti OiJ3 Depth of ilfiitary at middle - 036 Depth of dentary at elcveiitli tooth 048 Tbickuess of dentary at eighth tooth 018 Pappichthys LiEvis Copc. Auuual Keport U. S Geol. Surv. Terrs., 1872 (1873), p. 636. Plate lU, figs. 2-11. Represented by various fragments, including dentary and vertebral bones. The former differs from that of the species just described in the smaller .size of its teeth, there being six in a space occupied by but four in it, at a point where the dentaries have equal depth. In other words, there are four in .0250 m. The alveolar face is also much more oblique, being in fact continuous with the inner face of the bone. The external face of the dentary is smooth and thus different from that of P. sderops. The pre- maxillary bones of opposite sides are not coossified with each other, and they are narrowed fore and aft at their anterior suture. The posterior side of the distal half of the bone is beveled for the anterior process of the maxillary. Its alveolar face is marked for the bases of six teeth. The pos- terior face of the inferior quadrate shows the symplectic to have been a large bone, and to have descended nearly to the condyle of the former. Some fragments of the top of the skull show that it was roughened with low, obtuse ribs and lines. A dorsal vertebra is but little wider than deep and is truncate below, presenting a prominent infero-lateral angle. Measurements. H. Depth of dentary near middle 0:f7 ThiekiiesM of denlury near middle 01'2 Depth of eentnim of vertcl)ra (l*.?9 Width of otntnim of V(rt"^. This order, so extensively developed in recent times, first appears in geological history in a single genus in the Bridger Eocene. It has not yet been found at a lower horizon than this. These earliest forms do not differ widely from recent ones, so far as appears. RIIINEASTES Cope. Procced.Amer. Pbilos. Soc.,1872, p. 486 (published August 20, 1872). Annual Beport U. S. Geol. Surv. Terrs., 1872 (1873), p. 638. This genus differs from those at present inhabiting North America in the presence of teeth on the vomer (B. cdlvus). The teeth are everywhere coarsely villiform. The occipital bone exhibits a pit on the middle line below, and a surface for attachment for the inferior branch of the post-tem- poral on each side {JR. calviis, B. smithii). The modified anterior vertebrae mass is deeply grooved below {B. smithii). The cranium is covered with a rugose exostosis {B. peUatus, B. calvus, B. smithii), and has a strong closed groove in the position of the usual fronto-parietal fontanelle. The verte- brae (B. smithii) are short, and the sides of the centi'a only striate with the circumference. There are no lateral pits, but a pair above and a pair below, with a coossified apophysis at the base of one of them. The spines preserved belong chiefly to the pectoral fin. They are strongly striate and weakly dentate, and have the usual hinge with superior recurved flange above, and two embracing processes below at the base. The dorsal spine is weaker in B calvus, but strong in B. peltatits. In the former species it stands on the transversel}' expanded summit of the intert neural bone, which presents a median process upwards and an articular face on each side upwards and backwards. The median process is divided from above, and the excavation receives a subglobular enlargement of the middle of the base of the spine. This, with the two lateral facets of the basal expansions of the spine, constitute the hinge on which the latter moves. This genus differs from those at present inhabiting the fresh waters of North America, not only in the presence of vomerine teeth, but also in the exostosis of the superior and lateral surfaces of the skull. The anterior part of the cranium being absent from my specimens, I am not able to determine whether Bhineastes should be referred to the Pimehdina or the NEMATOGXATHI. 63 Ariina of Giinther's system. In the former case the genus resembles the Phractocephalus or the Piranmtana. In the latter case it will fall into the immediate neighborhood of Arius. These three genera are at present existing in South America, so that it appears that the Nematognatld of the Eocene of the Rocky Mountains present the same neotropical resemblances to be traced in the Dajjedoglossus and Priscacara. M}^ expedition obtained remains of four or five species of this genus from the Bridger beds, and one from the Amyzon beds of Colorado; but none have as yet been discovered in the shales of the Green River formation. The species are distinguished as follows : I. Rhineastes ; a large, massive iiucbal shield. Cepbalic o.ssificatiou pappilliforiu B. peltatus. II. Astephus; nuchal shield uarrow and short. Cephalic ossification in smooth lines; one basiocciijital pit; pectoral spines serrate on both edges B. smithii. Three basioccipital i)its; pectoral spines serrate on both edges B. calvus. Pectoral spiues serrate behind only; curved B.Mrcvatus, The cephalic bones of the B. arcuatus are unknown. Rhineastes peltatus Cope. Proceedings American Philosophical Society, 1872, 486. Plate V, figs. 1-2. Established on cranial and other bones with spines of a siluriform fish of the size of, perhaps, the Amiiinis lopli'ms. The form and the excessive rugosity of the external bony surfaces, reminds one of some of the Brazilian Dorades. The frontal fontanelle is closed, though very distinctly marked by a deep groove, with its fundus smooth. The rugosity consists of innu- merable well distinguished osseous papillae. The cranial ossification is con- tinued posteriori}' as a shield, which is strongl}^ convex from side to side. The spine is symmetrical and probably dorsal. It is compressed and curved antero-posteriorly, and is deeply grooved behind Laterally it is closely striate-grooved; the anterior face is narrowed, obtuse, and minutely serrate, with cross ridges; each side of it is rugose, with several irregular series of pronounced tubercles arranged transversely. 64 THE WASATCH AND BRIDGEE FAUN^. Measurements. X. Width frontal bono near firont of fontanelle 0.012 Thickness at same point 004 Thickness of casque 004 Width spine 005 Depth spine 009 The single individual of this species whose remains are preserved shows that it was the most robust, though not the largest of the genus. I found it on South Bitter Creek in the Washakie basin of the Bridger forma- tion. Rhineastes SMiTHii Cope. Proceed. Amer. Philos. Soc., 1872, p. 486 (August 20). Annual Report U. S. Qeol. Snr\-. Terrs., 1872, p. C39 (1873). Plate V, figs. 5-11. Represented by remains of several individuals, including one with vertebrae, basioccipital, opercular and other cranial bones, with spines. They indicate a fish of the size of the large catfishes of the Ohio River. The pectoral spines are quite compressed and distinctly striate-grooved on the sides. The posterior groove is occupied by short, spaced, recurved teeth ; the anterior by an acute edge, bounded by a gi-oove on each side, which has a fine, close serration. The surface of the modified vertebral mass is sti'iate ridged ; that of the basioccipital still more strongly ridged. In the latter there is a median pit behind, and the points of attachment of the inferior limb of the post-temporal is in front of it, smooth, and without reverted edges. The operculum has a large compressed, sessile cup, and its external .surface is strongly ridged and grooved, radiating from above in front. Measurements u. Diameter of a vertebra 021 Length of centrum 009 Diameter of moditicd vertelirn 013 Diameter of groo vo of vertebra 005 Diameter of occipital articulation 015 Length of cup of operculum 013 Diiimeler of spine at base 008 Diameter of spine at .004 from base 0037 Another pectoral spine is larger; diameter at base .010. From the Mammoth Buttes and Laclede, on South Bitter Creek.* • Named for my respected friend, Daniel B. Smith, of Gerraantown, Philadelphia, many years principal of Haverfurd College, ond a student and lover of natural sciences. NEMATOGNATHI. 65 Rhineastes calvus Cope. Annnal Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 640. Plate V, figs. 3-4. Represented by several specimens, including most parts of the cranium, spines, etc. One of these shows the supraoccipital production to have the form of an equilateral triangle, with a sinus of the posterior border on each side of it, which advances in front of the epiotic bone below. Shortly in front of this point the deep groove representing the fontanelle commences. The cranial rugae are lines parallel to the fontanelle, which diverge to the margins of the occipital prolongation, and are frequently connected by cross-ridges. The frontal portion of the skull is much expanded laterally, and the part beneath inclosed by the prefrontals, particularly wide. The fontanelle in this region does not appear to have been entirely closed. The surface is here also strongly rugose. The vomer has a T-shaped anterior extremity, which is immediately followed by two transverse paral- lelogrammic patches of premaxillary brush-teeth in several rows. They are about twice as long as wide, and in contact medially. The anterior margin of the premaxilla projects their length beyond them, and is perfectly smooth, and has a smooth, rounded border. The basioccipital has a sub- cordate cotylus. In front of the median inferior pit are three groove-pits ; the articular face for the post-temporal is opposite the former and is rugose and has strongly reverted edges. Measurementg. M. Diameter occipital articulation DOBS' Diameter base supraoccipital shield 0130 Width front above orbits 0043 Length from vomer to premaxillary border 0110 Length of both tooth patches 0120 Diameter pectoral spine at base 0031 The pectoral spine is seiTate on both edges. The base of the dorsal is symmetrical and articulates with its intemeural bone by two lateral flat, and one convex median anterior surfaces, whose surfaces are curiously rugose. The intemeural has a rugose median superior keel, which termi- nates in a point which is received into a pit of the base of the spine ; there 5 o 66 THE WASATCH AND BEIDGER FAUN^. is a similar production on the posterior side for a similar purpose. The basis of the spine proper is smaller than that of the pectoral, and is about as wide as deep. In a number of fragments of another indi\ndual found together, the basioccipital has the characters already described. The dentary bone is curved inward, and is acute below, widening regularly to the alveolar border. There is no groove on the inner face, while the outer is striate- grooved and has a series of pits along its lower middle. Measurements. It Diameter occipital articnlation 009 Width alveolar face. 004 Depth ramus at middle 008 A part of the operculum of a third individual (with similar spines) displays great rugosity and elevated radiating ridges; length of articular cup ".OOGS. The specimens are chiefly from the bad lands of the Upper Green River. Rhineastes aecuatus Cope. Plata V, fig. 12. Annnal Report U. 8. Geol. Snrv. Terra., I^f72 (1873), p. C41. Pimelodus antiquus Leidy, Final Report IT. S. Geol. Siirv. Terw., i, 1873, p. 193, PI. xvii, figs. 9, 10. Proceedings Academy Phila., 1873, p. 99, name only. There are numerous spines about the size of those of the last species, which differ in the want of the fine serrated anterior edge. I select one aa the type, wliich belonged to the pectoral fin of the right side. It is unbroken, and is curved from base to apex. The latter is acute by an oblique posterior truncation. The surface is strongly striate and the teeth of the posterior edge are closely set ; the proximal point distally, the distal proxiniall}-. In this specimen there is a trace of anterior serration ; in many specimens none whatever. The external surfaces of the epiclavicular and coracoid bones are strongly rugose-striate, as is the case in all the species of this genus, and the most characteristic fragment is that portion of the scapular arch at the base of the pectoral spine. Measurements. u. Length of Hpinc on riin'c 052 Dianii'tcr at liane; long 006 Diameter at banc ; iihort 004 ISOSPONDYLI. 67 The recurved plate of the base is rugose as in other catfishes. The spines themselves are less compressed than in B. calvus. It is probable that the name applied by Dr. Leidy to this species was published a short time before my own, but as it was not accompanied by a description it cannot be used. From the Bridger beds of the Upper Green River. ? Rhineastes radulus Cope. Annual Report U. S. Geol. Siirv. Terrs., 1372 (1873), p. 639. Plate V, figs. 14-17. This species rests on a number of broken cranial bones. I referred it fonnerly to this genus, but now regard the reference as purely provisional. It is likely that it does not belong to BJiineastes, but what its proper generic position is, I am not at present able to determine. The cranial bones pi'esent a pattern of exostosis quite distinct from that observed in the known species of Rhineastes. This consists of closely placed crenate ridges, which radiate from various points, and are sometimes broken up, but always rough or serrate on the edges. The bones are not so thick as in the R. peltatus; i. e., .0025 m. - ' From bad lands of Cottonwood Creek, Wyoming. ISOSPONDYLI. Cope, Proceedings American Association for the Advancement of Science, 1871, p. 33. Actinopterous fishes with physostomous characters, having the scapular arch suspended to the cranium; a praecoracoid arch, and a symplectic bone, but no coronoid bone, and with the anterior vertebrae unmodified and with- out ossicula auditus. Two families of this order are represented in the Green River and Bridger beds by numerous individuals. These are the OsteoglossideB and the Clupeidce, which are distinguished by the following characters of the skeleton : Tail, homocercal; pterotic bone, normal; basis cranii, double; superior pharyngeals four, distinct, third largest and directed forwards; basal bran- chihyals three; parietals separated by supraoccipital; one vertebra included 68 THE WASATCH A^TD BRIDGER FAUNJ3. in the caudal fin. (Psuedobranchite and pyloric appendages). Clupeidth at middle anal ray 027 Depth at base of caudal tin 016 This Herring is repi'esented by a great number of well-preserved spec- imens, and was, next to the Z>. humilis, the most abundant fish of the waters of the ancient Green River Lake basin. It is distinguished from the D. dentatus by the large number of anal and smaller number of dorsal radii, and by the shorter head and relatively more slender body. The specimen measured represents the average size; the largest obtained is half as large Again, and much smaller than the type of D. dentatus. From Twin Creek, Wyoming. DiPLOMYSTUS PECTOEOSU8 CopO. Bulletin U. 8. Geol. Surv. Terrs., 1877, p. 810. Plat* X, fig. 3. This Clupeoid is represented by small specimens of a deeper form than that seen in the two preceding species. It is also characterized by a smaller number of dorsal radii than either of them. Formula: D. I. 8-9; A. I. 40-44. VertebriB: dorsal, 16-17; caudal, 22. The greatest depth is in the pectoral region, and enters the length minus the caudal fin a little less than three times. The outlines contract from the ventral fins, and the anal region is longer than the abdominal. The eye is a little more than one- fourth the length of the head, and the latter enters the total minus the ■caudal fin three and a half times. The ventral fins are small, and commence well in advance of the line of the dorsal. The last dorsal ray is nearly above the first anal ; the caudal is deeply forked. As in the two preceding species, the neural spines in front of the interneurals present a laminar antero-posterior expansion. The dorsal scuta are furnished in the D.pectoro- 3US with an especially prominent median keel. ISOSPONDYLI. IT Measurements. u. Total length 090- Length (axial) to below D. 1 038 Length (axial) to above A. 1 043 Length (axial) to base of caudal fin 070 Length of head 022 Depth at orbit OIT Depth at pectoral fin 026 Depth at dorsal fin 024 Depth at caudal peduncle 008 r This species is represented by several specimens, from Twin Creek Wyoming. DiPLOMYSTUS THETA Cope. Bulletin U. S. Geol. Surv. Terrs., 1877, p. 811. Clupea iheta Cope, Annual Report U. S. Geol. Surv. Terrs., 1873, p. 461. Represented by a specimen from the Green River shales near the mouth of Labarge Creek, in the upper valley of Green River. It is a larger species than the C. Immilis Leidy, which is also found at the same locality, and it has much longer anal fin. Its radii number 26, possibly a few more, as the end appears to have been injured. The dorsal fin is short; the last ray in advance of the line of the first of the anal. The body is deep. Number of vertebrae fi-om the first interneural spine to the last interhsemal, 29. Depth at first dorsal ray, .04«5; depth at last anal ray, .0170; length of 29 ver^ tebrae, .0780. The posterior part of the body having been lost, the number of anal rays is unknown. It is quite possible that further investigation may show that the -D. analis is identical with this species. DiPLOMYSTUS HUMiLis Leidy. Proceed. Acad. Phila., 1856, p. 256. Final Report U. S. Geol. Surv. Terrs, i., p. 195, Plate xvii, fig. 1. Clupea 2>wiUa Cope, Proceed. Amer. Philos. Soc, 1870, p. 382. Annual Report U. S. Geol. Surv. TeiTS., 1870, p. 429. Plate rx, fig. 8; Plate X, fig. 4. This and the following species, already referred to a distinct section of the genus Liplomystus, difi'er from those above described in several points. They have a much shorter anal fin, and the caudal part of the vertebral column is thus shorter. The anterior neural spines do not present the antero-posterior laminar expansion. The ventral fin commences a little 78 THE WASATCH AND BRIDGER FAUNiE. behind the origin of the dorsal. The formulae for the D. humilis are as fol- lows:—Radii: D.I— 11; A. I— 14. Vertebrtv: D. 21; C. 13. Depth to length as 3 : 8. 5. Specimens of this fish are equally abundant at the Green River and Twin Creek localities. A rather small specimen from the former place was described by me as the type of another species, but I think it represents merely a young individual. When I described it I was under the impres- sion that the D. alius was the true D. humilis of I.,eidy. This view was justified by Dr. Leidy's description of the D. humilis, where the measure- ments given are those of the B. alius. The figures given (3J inches long by 16 lines deep) are, however, partly erroneous, as they do not agree with those subsequently given, nor with the plate above cited. The description of a Green River specimen is as follows: Greatest depth contained four times in the total length or 3.5 times to basis of caudal fin. Length of head 3.2 to basis caudal. This measure- ment may require revision, as the end of the muzzle is slightly injured. Orbit large, contained twice in length of head behind it. Middle of dorsal fin near the middle of the length, and about over the origins of the ventrals. D. II, 1 1, V. 7. Pectoral extending half way to ventrals. Vertebrae, 2!)-30; dorsals, 16-20. Ventral keeled ribs, 18. Anal fin lost. Caudal peduncle slender caudal fin deeply furcate. Length, ".044; greatest depth, "Oil. A second specimen exhibits the characters of the species more dis- tinctly in some respects. There are 30 vertebrae, of which 13-14 are caudaL The general shape is regularly fusiform, and the head rather acuminate. ' Measurements. H. Total length 054 Lc;nj;th to preopercnlar edge 01 Li'iinlli to opercular edge 013 L«iiglli to posterior margin dorsal (H55 Length to anterior margin anal .034 Length to Iibho lauilal 044 Depth at oroiput .011 Dejith at middle of dorsal 0116 Depth nt caadal peduncle '. 0046 The largest specimen of this species which I possess is "150 in length. PEECOMOKPHI. 79 As at the Green River locality, so at Twin Creek, this Herring is the most abundant species One-third the entire number of specimens are referable to it. DiPLOMYSTUS ALTus Leidy. Cope, Bulletin U. S. Geol. Siirv. Terrs., 1877, p. 811. Clupea alta Leidy. Final Eeport U. S. GeoL Snrv. Terrs., i, p. 196 Plate XVII, fig. 2. This small Herring is abundant in the Green River shales, both at Green River and at Twin Creek. It is distinguished from the D. humilis by the greater relative depth of the body, resembHng in this respect the D. pectorosus. The difference which it presents in this respect is rather too great to permit its union with D. humilis. Nevertheless intermediate speci- mens occur, but their characters are sometimes found to be due to distortion. Formulge:— Radii: D. I. 11; A. 1. 13-15. Vertebra: D. 22; C. 12. Depth to length (without caudal tin) as 4 to 8. Size that of the D. humilis. PERCOMORPHl. Cope, Proceedings American Association for the Advancement of Science, 1671, p. 341. Physoclystous Actinopteri, with the shoulder-girdle attached to the skull, and thoracic or jugular ventral fins. Maxillary and dentary bones distinct; cranium symmetrical; epiotics normal; no interclavicles ; post- temporal not coossified with cranium. Basal pectoral radii not enlarged ; femora suspended (generally) from the scapular arch. Basibranchials thi-ee; superior pharyngeals with the third usually the largest; sub and interoper- culum present, plate-like. Three families are represented in the Eocene Tertiary beds, two of which certainly belong to this order, and the third very doubtfully. The former are the Percidce and IPomacentridcB, representing the suborders Distegi and Pharyngognathi, respectively. The third group, represented by the genera Amphiplaga, Trichophanes, and Erismatopterus, is related to the AphododiridcB ;* and as I know of no characters as yet by which to distin- guish it, shall for the present consider it under that head. This family lies on the extreme verge of the order towards the Haplomi, to which the genus Erismatopterus almost affords a transition. * This name is variously spelled, and I am not yet suie as to the orthography to be adopted. •^^ 80 THE WASATCH AND BRIBGER FAHN^. ERISMATOPTERUS Cope. Annual Report U. 8. Geol. Snrv. Terra., 1870, p. 427. Dorsal and anal fins short, with two or three strong appressed support- ing spines in front; no other interhaemal spines than those supporting those of the anal fin. Dorsal fin above the anterior median or posterior abdom- inal region. Ventrals originating in front of or opposite to the origin of the dorsal. Pubes sending a limb upwards, which is in contact with the inferior post-clavicle. Teeth minute or (I) wanting. Caudal fin bifurcate. I originally referred a species of this genus to the Cyprinodontida, and many of the characters are similar to those of that family. The arc of the mouth is formed by the premaxillary bone, and the ventral fins have a rather anterior position, which is neither pectoral nor ventral, and the caudal is furcate; the scales are cycloid. The strength of the spinous fin radii and supporting interhfemal spines attracted my attention, and on careful exami- nation I observe other approximations to the type of Asineops and the Aphredodiridce. The inferior post-clavicle is very long and styliform, as in the latter genus, and the pubic bones are slender and directed upwards, so as to rest on the post-clavicles. In one specimen there appears to be an anteriorly directed pubic limb, but this does not exist in other specimens. The pubes do not reach the clavicles, as in true Physoclysti. Vertebrae hour-glass shaped. Ventral radii seven, in the species E. rickseckeri and E. endlichi. Erismatopterus levatus Cope. Annnal Report U.S. Geol. Sorv. Terrs., 1870, p. 428. Cyprinodon lecatui Cope. Proceed. Amer. Philoa. Soc, 1870,p.382. Plate rx, fig. 6-7. Anterior margin of anal fin commencing a little behind, opposite the posterior margin of the dorsal. VertebrjE : 11-14-5, seven between the interneural and interhaemal bones of the dorsal and anal fins. Radii: D. 8, A. II. 8, V. 8. Caudal fin deeply furcate; first anal ray strong. General form elongate, the greatest depth contained three times in the length be- tween the scapular arch and the basis of the caudal fin. Scales preserved, small; seven longitudinal aeries above and seven below the vertebral PERCOMORPHI. 81 column, probably two rows concealed by it. The caudal peduncle is but little contracted. Length from scapular arch to extremity of caudal, ".0335; depth at origin dorsal fin, ".008. Measurements. u. Total length No. 2 055 Length of cranium '. 013 Length to basis D. I 0232 Length tobasisA. I 033 Length to basis V. I 0205 Length to basis caudal - 0466 Depth at D. I 01 Depth of caudal peduncle 0058 There are many individuals on the slabs of Green River slate, some of them perfectly preserved. Many of these slabs represent that portion of the stratum which is highly carbonaceous, portions of it thrown into the fire burning freely. Dr. Hayden, who has brought numerous specimens from this locality, informs me that the laminae exhibit greater numbers of these little fishes. No doubt the carbonaceous character of the shales is due to the decomposition of their bodies. The nature of the deposit, and mode of preservation, remind one strongly of the Cyprinodon meyeri of Agassiz, from the neighborhood of Frankfort-on-the-Main. That species dififers specifically in presenting 18 anal radii. Some of the specimens above described were obtained from the Green River Cut, and preserved for scientific study, by L. E. Ricksecker. Erismatopterus eickseckeri Cope. Annual Report U. S. Geol. Surv. Terrs., 1870, p. 427. Plate VI, fig. 2. Length, three to four inches; head large. Vertebrae: D. 13 ; C. 1(J; r= 29, ten between the intemeural bone supporting the first dorsal ray, and the first interhsemal supporting the first anal ray. There are only seven in this position in E. levatus. Anterior dorsal ray anterior to the point half way between end of muzzle and end of vertebral column. Branchiostegal radii fin distinguishable. Head stout, mouth terminal, orbit equal length of muzzle; maxilliarv bone reaching line of middle of orbit. Scales 6 o 82 THE WASATCH AKD BEIDGER FAUN^. small, with numerous concentric and no radiating giooves. Fin radii: D. 11, —8 (last split); C. 8—19—8; A. II— 9. V. 7, p. 15. Measurements. M. Total length No. 1 0743 Cranium to supraclavicle 018 Length to base D. 1 029 Length to end vertebral colonin 06 Length of A. II 008 Length of cranium No. 2 .0175 Length to prcopcrculum 012 Length to D. I 0275 Length to A. 1 043 Five more or less complete specimens of this fish were obtained by Lucius E. Ricksecker from the Green River shales, and I dedicate it to him in recognition of his interesting discoveries in this department. Its difference from E. levatus is seen in the more anterior position of the dorsal fin, more numerous vertebrae, etc. Ebismatopteeus ENDLicni Cope. Bulletin U. S. Geol. Snrv. Terrs., 1877, p. 812. Plato Xn, fig. 5. The radial formula in this fish is: D. Ill— 11 ; C. 6-19-6; A. Ill— 7. V. 7. The vertebrae are: D. 13; C. 17; Centra between the lines of the first interneural and first interhaemal spines, 10. Ten rows of small scales visible above the vertebral column. The general form of the fish is stout, and the caudal peduncle is deep. The top of the head is convex, and the eye large. The front descends abruptly to the rather projecting muzzle in the specimen, but whether this is a distortion or not is uncertain. The coracoid is wide and well produced backwai-d, while the clavicle is, as usual, directed forward. The femur is slender, and connected with its fellow by a posterior transverse bar. The greatest depth is a little less than one-fourth the length without tlie caudal fin. The diameter of the eye is one-fourth the length of the head. The origin of the ventral fin is in advance of the first dorsal ray; the origin of PEECOMOEPHI. 83 the anal is below the penultimate dorsal ray. The caudal fin is openly forked. Measurements, M. Total length 061 Length of head 016 Length to line of ventral fin 020 Length to line of dorsal fin 022 Length to line of anal fin 031 Length to base of caudal fin 048 Depth at caudal peduncle 008 Depth at dorsal spine Oil The more numerous rays of the dorsal fin, and more numerous scales are among the characters which distinguish this species from the two above described. It is dedicated to Dr. Frederick M. Endlich, geologist in charge of one of the parties of the United States Geological Survey of the Territories under Dr. F. V. Hayden. AMPHIPLAGA Cope. Bulletin U. 8. Geol. Surv. of the Terrs., 1877, p. 812 (August 15). Generally as in ErismaUypterus, but with strongly ctenoid scales. The dorsal fin is over the abdomen, and is supported by a few strong, adherent spines in front, which rest on stout interneurals; the soft rays have no inter- neurals, either in this fin or the anal. They are present in Erismotopterus. The ventrals originate a little in advance of the line of the dorsal, and the caudal fin is deeply forked. This genus approximates Aphrodedirus. The scales in this genus are thin and like those of Trichophanes. In other respects Amphiplaga resembles that type, and I have only distinguished it on account of the absence of interneural bones below the soft dorsal radii. It has occurred to me that this may be abnormal or due to accident, but the bases of the dorsal radii, as well as the anterior interneural bones, are perfectly preserved, so that the accidental removal of the posterior interneurals seems improbable. It must also be remembered that the inter- hsemal bones are absent from the soft anal rays in both this genus and in Erismatopterus. But one species of this genus is yet known. 84 THE WASATCH AND BRIDGER FAUN^. Amphiplaga bkachyptera Cope. Bulletin U. S. Geol. Surv. Terrs., 1877, y,. 812. Radii: D. II — 8; A. Ill — 4. Vertebrae of the caudal series 15. Scales: transverse row, 22; longitudinal row behind first interneiiral bone, 40. The only specimen I possess lacks the head, so that various characters cannot be ascertained. The depth of the body at the first dorsal spine enters the length from that point to the base of the caudal fin two and a half times, giving a general form of medium proportions. Caudal peduncle stout. The vertebrce are contracted medially, and not shortened; they have two or three longitudinal keels, which are somewhat irregular in their connec- tions. This species is larger than any of the Erismatopteri yet known. Measurements. ^ u. Length from first dorsal spine 073 Length from first anal spine 051 Length of aual fin 023 Length of second dorsal spine .' 015 Length of third anal spine 013 Depth at first anal spine 018 From the Green River shales at Twin Creek, Wyoming. ASINEOPS Cope. Proceed. Amer. Philos. Soc., 1870, p. 380. Annnal Report U. S. Geol. Snrv. Terrs. , 1870, p. 425. Branchiostegal radii, seven; ventral radii I. 6-7. Opercular and other cranial bones unarmed; scales cycloid. Spinous and cartilaginous dorsal fins continuous; caudal rounded; anal with two spines. Lateral line distinct. Operculum with regularly convex posterior border. Teeth coarsely villiform, without canines. Both spinous and soft portions of dorsal and anal fins moderately scaly. This well marked genus is established on the remains of numerous individuals, in various states of preservation, so that the characters undis- tinguishablo in one can be discovered in another. Thus the lateral lino is preserved in one only, and the teeth in another. In none can I be entirely sure that I see the vomer. The scales are preserved in many specimens, and I cannot find a ctenoid margin in any, nor any radiating sculpture, but delicate concentric PEKCOMOEPHI. 85 ridges continued round the central point proximally, distally forming para- bolic curves, the less median not completed, but interrupted by the margin of the scale. Near the margin all the ridges become gently zigzagged. There is no depression between the two portions of the dorsal fin, though the cartilaginous portion is the more elevated. Laid backwards, the latter is in line with the extremity of the anal, and both extend beyond the basis of the caudal. The affinities of this genus are rather obscure, but are in some degree to that aberrant family of Physoclysti, the Aphredodirida. This is indi- cated by the increased number of ventral radii, the slender separated pubes, and the reduced number of interneural spines. The Aphredodiridce betray Physostomous tendency in the same characters, with still greater reduction of the spinous dorsal and anal fins, though its ctenoid scales and spinous orbital and preopercular bones are of Physoclyst significance. In Asineops the scales are cycloid, and the cranial bones unarmed. The ventral fins occupy nearly the same position as in the extinct genus Erisniatopterus Cope, which accompanies it. There is at least in these genera another illustration of the approximation of forms now very distinct, in past periods. The pubes are, however, supported by the clavicles in Asineops, and by the ^wst-clavicles in Erismatopterus, though the latter bones are very long in Asineops also. Asineops will thus constitute a family Asineopidce difieriug from the Aphre- dodiridas in the simple pubes. I suspect that the genus Pygceus of Agassiz will be found also to belong to it, though the increased number of ventral radii is not assigned to it in the Poissons Fossiles. Some of its species may even be found to belong to Asineops. Nine species are described by Pro- fessor Agassiz, all from Monte Bolca, in Italy, from an Eocene stratum. Asineops squamifrons Cope. Proceed. Amer. Philos. Soc, 1870, p. :381. Annual Eeport U. S. Geol. Surv. Terrs.,, 1870, p. 426. Asineops viridensis Cope. Annual Eeport 1870, p. 426. Plate rX, fig. .5; PI. x. General form suboblong, the greatest depth just behind the head, and contained two and a half times in the length exclusive of caudal fin. Radii D. VIII— IX, 14; A. II, 11-12; C.14;V.I, 7; P.?ll?13. Scales5— 86 THE WASATCH AND BRIDGER FAUNiE. t30 — 10, vertical line counted a little behind the ventral fins. The line of the extremities of the second dorsal and anal fins, marks the basal third of the caudal fin. The dorsal spines are subcylindric, slightly curved, and of nearly equal length; the length equals the depth of the body at the middle of the second dorsal fin. The external series of villiform teeth are stout of their kind, conic, and a little incurved. I cannot see the pharyngeal bones or teeth. The number of vertebrae which extends between the caudal fin and the superior margin of the operculum, where one or more are concealed, is twenty- five, of which fifteen are of the caudal portion (in two I can only count fourteen). The mouth is directed obliquely upwards and is rather large; the man- dible, when closed, does not project beyond the premaxillary border. The maxillary, where preserved, is naiTOw distally, and does not project beyond the posterior line of the orbit. The latter is rather small, and though not well defined in any specimen, is not more than one-eighth the length of the head, and 1.5 to 1.75 times inside of muzzle. The margins of all the oper- cular bones are entire and smooth. The interoperculum is narrow, and lies obliquely upwards, narrowing the operculum. The greatest width of the latter is more than two-thirds its depth. The pelvic supports of the ventral fins are simple, slender and in contact anteriorly, their length about half that of the fin. The pectorals are not elongate. The scales extend over the top of the head, to or beyond the orbits. They also extend along the ramus of the under jaw. Those of the fins are quite small, they extend to a considerable distance on the unpaired and on the caudal fins. Measurements. M. Total Iciigtii of tho largest specimen 19 Do. No. 2, smaller example (with caudal) l~ Length of hcail of do 014 Depth of 7 Length to first anal spine 0r>7 Length to base of caudal 086 Dei)th at orbit 0:iO Depth at first dorsal spine Ol:J Depth at first dorsal soft ray 035 Depth of cauilal peduncle 014 Two specimens of this fish have been received from Twin Creek. Tliey are somewhat injured, and it is possible that better specimens will show minute serrations of the preopercle. Priscacara testudinaria Cope. Plate I, fig. 7. My best specimen of this fish is without the greater part of the skull; othenvise it is nearly complete. Under the circumstances it is difficult to make a final generic reference, but as the parts jireserved are identical witli those included in the definition of the genus Priscacara, I refer it here for the present. The specimen is larger than those which I have seen of the other PEECOMOEPHL 99 species of the genus, agreeing in this respect with another which I have seen in the museum at Salt Lake City. It is also more elongate in its form, and is further characterized by its large scales. The more general charac- ters are, the undivided dorsal tin ; the wide interneural spines, and the well developed basilar interneurals. Also the haemal spines of the caudal fin retain the division into three or four parts. The vertebrae have a flat medi- an, lateral rib, bounded by a fossa above and below. The lower border of the inferior fossa on the dorsal vertebrae is deflected. The anterior base of the neural spine is excavated on the second, third, and fourth vertebrae, behind the scapular arch. The lateral rib of the second is oblique vertical. On the fifth and sixth it has an excavated, down-looking superior border. The scales, which are beautifully preserved, though much disarranged, are about as deep as long, with the anterior border subtruncate. The borders, excepting the posterior, are marked with four lines of growth, and from fivo to ten grooves radiate from the center, across the posterior border lines. There are numerous minute elevated points on the center of the scale, and the same reappearing on the posterior border, give the ctenoid character. Radii: D. XI — 12; A. -f 21 -{-. The number of the rays of the infe- rior fins cannot be ascertained, but there may be counted between the first and last, the impression of eleven interhaemal spines. The dorsal spines are very stout, and the first is very short. The ventral spine is not very long, but is very robust. The interhaemals that support the anal spines are extraordinarily robust. The outline of the body is an elongate oval, the depth at the ventral fin entering the length without the caudal fin (or head) two and two-fifths times. Vertebrae: D. from scapular arch, 8; C. 16. Measurements. M. Length ■svithout head and caudal fin 255 Depth at posterior base and fin 044 Length of series of caudal vertebrie 140 Depth from vertebra to ninth dorsal spine : 026 Vertical diameter last dorsal vertebra OH Length of fifth dorsal spine 052 From the calcareous shales of the Lower Eocene, near Manti, Utah. A small specimen, apparently of the young of this species, was sent me by Dr. A. S. Packard. It is of a more elongate form than any of the other 100 THE WASATCH AND BRIDGER FAUN^. species assigned to this genus, the depth at the first dorsal (the length of the head) entering the total four times. The muzzle is short and the eye large, apparently in consequence of the immaturity of the fish. Radii : Br. 5; D. X — 8; A III — 12. Vertebrae from edge of operculum, D. IX, C. XIV, or from two to four more than in any other Priscacara. The three spinous anals are robust as in other species of the genus, while the first ventral spine is long and strong and deeply ground on the inner side. The numbers of soft rays above given is subject to revision owing to the condi- tion of the specimen. Total length, M , .058. From the shales of City Creek Canon, near Salt Lake City, Utah. This specimen indicates a great northern extension of the Manti shales. BATRACHIA. Remains of Batrachia are rare in North American formations later than the Permian. There are two or three species of Stegocephali known from the Trias, above which formation that order is not known to extend in any coun- try. No Batrachians have been obtained from the Jurassic or Cretaceous systems excepting from the top of the latter, in the Laramie. Here occur the genera Scapherpeton and Hemitrypus Cope. A single specimen from the Eocene is mentioned below, and then wo miss them until the Loup Fork or Upper Miocene, where Anura and salamanders have been found. The vertebral column and part of the cranium of a probably incom- pletely developed tailless Batrachian, were procured by Dr. F. V. Hayden, from the fish shales of the Green River ep6ch, from near Green River City, Wyoming. They are not sufficiently characteristic to enable me to deter- mine the relation of the species to know forms. It is the oldest of the order Anura yet discovered, the fossil remains of the known extinct species having been derived from the Miocene and later formations of Europe. REPTILIA. 101 REPTILIA. The Eocene period, was, of the divisions of the Tertiary, the most prolific of reptilian life. It is true that the orders of reptiles which charac- terized the Mesozoic periods no longer existed. The Dinosauria had perished from the land; the Ichthyopterygia, Sauropterygia and Pythononiorpha no longer inhabited the sea, and the Pterosauria had disappeared from the air. The Eocene reptiles were not a new creation, nor a new evolution, but a remnant of the types that had coexisted with those monarchs of life during previous ages. We must except from this statement the serpents, which first appear at this time.* The crocodiles, tortoises, and lacertilians represent orders already abundant in the Mesozoic faunae. Their decadence in central North America did not commence until the Miocene period, when the crocodiles and nearly all the tortoises disappeared. From the Loup Fork or Upper Miocene, only a few traces of lizards have been obtained, and snakes were apparently not very numerous. On the eastern coast regions crocodiles existed, and tortoises were more numerous during the Miocene period; but here also they were less abundant and varied than during the Eocene. The Crocodilia did not differ in important respects from those now existing. I have distinguished five species from the Wasatch beds, and six different ones from the Bridger. The Tesiudinata include a great variety of forms. I have seen sixteen species from the Wasatch formation, and thirty-two from the Bridger and Washakie. Of these, six are common to the two formations, as indicated by imperfect material, leaving a total of forty-two. Three genera, Emys, Trionyx, and f Plastomenus hold over from the Cretaceous period, while six appear for the first time. Of these, five genera are not known to continue later than the Eocene period. Of lizards I have obtained the remains of a half dozen of species, but none of them in a complete state of preservation. Professor Marsh has been more fortunate, as he has described from his material from the Bridger beds, twenty-one speciesf He arranges these under five generic heads, as fol- • Since the above was written, it is reported that Dr. Sauvage, of Paris, has discovered the remains of a serpent in the cretaceous formation. i American Journal of Science and Arts, 1871, June, and October, 1872. 102 THE WASATCH AND BRIDGER FATIiTiE. lows: Thinosaunis Mai>h, five species; Glifptosattrus Marsh, eight species; Xest02)S Cope (1873, Oreosaunis Marsh, not Peters), five species; Tinosaurus Marsli, two species; and Iguanavus Marsh, one species. As Profesor Marsh does not give us any clue to the aflinities of these forms, they cannot be furtlier considered here. In Lieutenant Wheeler's Survey Report* I have pointed out that the dermal scuta and a few other fragments Avhich I obtained in the Wasatch beds of New Mexico, were probably referable to the Flacosaurida, a family created by Gervais to receive certain Lacerdlia of the Eocene of France. To this family no doubt some of the species described by Marsh from the Bridgor horizon are to be referred. The snakes of the Eocene are not very numerous as to species. The first known j^merican species {Palcrojihis Uttoralis and P. halidanus) were determined by myself from Kew Jersey specimens. None have been pro- cured from beds lower than the Bridger, and in that formation I found a single foi-m. Professor Marsh has described five species.* The whole number of species of reptiles thus far discovered in the Eocene of the central region of North America is as follows: Crocodilia 12 Tcstudiiiat.i 42 Lacertilia 22 Opbiilia 6 82 OPHIDIA. PROTAGRAS Cope. Paleontological Bulletin No. 3, p. 3, August 7, 1872. Aunual Report U. S. Gcol. Surv. Terrs., 1672 (1873) p. 632. Proceed. Amer. Philos. Soc., l!?72, p. 471. Transverse processes large, the extremity entirely occupied by the costal articular surfiice. This consists of a superior and an inferior convex por- tions, which are separated by a constriction, which is most profound on the posterior border. Zygosphene wider than articular cups, and giving rise to a low ridge which extends along the side of the neurapophysis. Articular ball and cuj) wider than deep, the former looking very obliqely upwards, its surface extending to the bases of the neurapophyses. A prominent ridge connects the pre- and postzygajjophyses. A strong hypapophysial keel, and a latero- inferior ridge extending posteriorly from the base of tlie transverse process. • Vol. iv, pt. ii, p. 42, pi. xxxii, figs. 26-36. OPHIDIA. 103 The only extinct genus with which it is necessary to compare the present one, is the Boavus* of Marsh, which was described more than a year previously. There are various points in which Professor Marsh's full description con-esponds with my specimens, but I observe two important dif- ferences: One is, that in Boavus the diapophyses are said to be "convex throughout," while here they present a median constriction, giving a figure eight outline. The other is, that the cup and ball are "more nearly verti- cal" than in Boa; the ball is very oblique in Protagras. The modern affinities of Protagras will be fully considered in connection with the Ophidia of the Miocene period in a later portion of the present work. But one species is known as yet. It was found in the Bridger beds of Wyoming. Protagras lacustris Cope. Paleontological Bulletin No. 3, 1872, p. 3. Proceed. Amer. Philos. Soc. loc. sup. cit. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 632. Plate XXUI, figs. 17-18. A serpent of about the size of the existing pine snake {Pityophis me- lanoleucus). A vertebra before me has the longitudinal hypopophysial keel horizon- tal, and terminating in a very obtuse point. The ball looks extensively upwards. The upjDer articular extremity of the diapophysis is short and obtuse, and the inferior equally so, and directed shortly downwards, their articular surface being continuous with each other. It sends an obtuse latero-inferior keel backward, which terminates distinctly in front of the ball. Its inferior angle stands below the inferior margin of the articular cup. The angle connecting the diapophysis and zygapophysis is strong, while the former is narrow. Measurements. M. Length of centrum with ball, below 0090 Elevation behind, total 0135 Elevation before, total - 0119 Width between di.ipophyses, below 0055 Width of articular cup 0054 Depth of articular cup 0043 Depth of inferior keel 0010 Found by myself in the Bridger bad lands of Cottonwood Creek, Wyoming. * American Journal Science and Arts, 1871, May. 104 THE WASATCH AND BRIDGEB FAUNiB. 1LACERTILIA. CHORISTODERA. Cope, Proceedings Academy Phila. 1376, p. 350. Vertebral centra amphiplatyan. Processus dentatus free from axis. Neural arches separate from centrum during maturity. CHAMPSOSAURUS Cope. Loo. oit. p. 348, pnblisbed Jan. 30, 1677. Paleoatological Balletin Xo. 23, p. 9, Jan. 10, 1877, Simado- taurua Gervais, Journal de Zoologie, 1877, No. 1, p. 76, f February. This genus was established on species found in the Laramie Cretaceous formation. It has been found to be abundant in the Puerco of the Tertiary series, and is hence introduced here. The characters presented by the vertebral column are the following: The ribs have a single head, which articulates with a prominent tuberculum, excepting those of the cervical vertebrae. On these there is a small capit- ular tubercle below the diapophysis. It commences very small, and inferior in position, being removed, in fact, but a short distance from the inferior middle line in the first vertebra in which it appears. It rises rapidly in the succeeding centra until it is merged in the tuberculum of the diapophysis. The latter projects from the neural arch, which is free from the centrum, but in none does the base of the diapophysis rise from a point above the floor of the neural canal. On the dorsals it is vertically compressed. One of the anterior cervicals, probably the axis, is obliquely truncated below its anterior articulate face, for a free hypopophysis or os odontoideum. This vetebra has no parapophysis, and the articular faces for the neurapophysis are superior. The few vertebrae in each of several series, probably from the sacral region, are more depressed than the others, and the facets for the diapophyses present a greater antero-posterior extent, but none are coossi- fied. The caudal vertebrae are distally quite compressed. In all, except the anterior ones, the neural arch is coossified with the centrum, and in such there are no diapophyses. In those with free neural arch, the facets for the neuropophyses turn down on the sides of the centrum. The articular extremities of the centra are plane, those of the caudal series slightly concave. There are no hypapophyses behind the axis, ex- CHORISTODERA. 105 cepting a longitudinal carina, which ceases to exist on the dorsal vertebrae. The zygapophyses are simple. The chevron bones are free. The relations of the atlas and axis, though not fully elucidated by my specimens, are peculiar. The former has separate neurapophyses, which have nearly the shape of those of the Streptostylicate Reptilia, resembling much those of the Pythonomorpha. Although I procured numerous cervical vertebrae, there are but few which exhibit the antero-inferior facet for sup- posed hypapophysis, already described. The position of this vertebra was in front of the first cervical which displays a parapophysis, and is, on this account, likely to be the axis or the third cervical vertebra. It is the more probably the axis, as there is no other among the large number of verte- brae in my collection which can be referred to that position. Its anterior articular face is smooth and like the posterior, showing that the odontoid bone was not coossified with it. Now in the Crocodilia the odontoid bone is united with the anterior extremity of the axis by suture, which may be- come coossified with age, while the free hypapophysis is w^anting. In the streptostylicate orders the hypapophysis is present, and the odontoid is above it, but united to the axis by suture. On the other hand, in the Rhyncho- cephalia, the axis is coossified with both odontoid and hypapophysis, and a few succeeding vertebrae possess fre^ hypapophyses. A few entire ribs and the heads of many others have been obtained. The cervical ribs are long, and the dorsals are relatively stout and shoi-t The head of an anterior dorsal is truncate and compressed, its articular face contracted, forming a narrow figure eight. The shaft is obliquely flattened. The extremities are separated from the lateral surfaces by a narrow angle, as though capped with cartilage in life, as in the Pythonomorpha. Bones of the extremities are very rare. One fragment resembles the proximal end of a crocodilian tibia, and another is like the distal half or more of the tibia of the same type. The above characters were derived from the Laramie species, and those of the Puerco agree with them exactly in those respects. The latter enable me to add, that the jaws are slender, and that the splenial bone of the man- dible is well produced anteriorly. The teeth are set in shallow alveoli, and are replaced from the inner side as in Lacertilia and Pythonomorpha. 106 THE WASATCH AND BEIDGER FAUN^. Dr. Lemoine has toimd this genus in the Suessonian formation near Reims, France, and liis material has enabled him to furnish some characters in addition to the above mentioned. He states* that the quadrate bone is "non sonde," find that the limbs resemble both those of Crocodilia and Lacertilia, and are apparently adapted to aquatic habits. Ignorance of the structure of the skull has prevented a definite conclu- sion as to the true position of this genus and its allies. Dr. Leraoine's ob- servation makes it appear that they belong to the Streptostylicate division, and that they form an aberrant division of the LacerfiUa or Pythonomorpha. For the present I refer them to the former, but they will constitute a dis- tinct sub-order with the definition given on a preceding page. Besides Champsosnurus, the Champsosaurklce include the genus Ischyrosaurus Cope, which difiers from it in the heavy subfusiform ribs, and the flat articulation between the centrum and neural arch of the vertebrae. This genus was named by Professor Gervais at nearly the same time with myself His publication was made in the February no. of the Jour- nal de Zoologie for 1877, and mine in the Proceedings of the Philadelphia Academy for December, 1876. My description did not appear until Jan- uary 10, 1877, and although I do not know of the precise date of the pub- lication of the Journal de Zoologie, it was presumably not until some weeks later. There have been four species of this genus described from the Ameri- can Laramie formation, viz: the C. profundus, C. annectens, C.brevicollis, and C. vaccinsulensis. The species from Reims is called C. lemoinei Gerv. I distinguish three species from the Puerco bed of New Mexico, which dift'er from the Laramie species in obvious ways. Vertebrae of a species from the Laramie were figured without name by Leidy in the Transactions of the American Philosoph. Society, 18G0. The Puerco species differ as follows: Small; dorsal centra witli semicircular faces, much wider than' deep; an- terior dorsal keeled below C. amtralis. Large; dorsals witii cordate faces aliti^le wider than deep; none known to be keeled below C. puereeitsit. Medium; length, width, and depth of dorsal centra equal; faces snb- - round ; not keeled below; axis not keeled below C. saponensis. "Coromnnication siir li-s Ossomcnts foagilcs desTerr. Tortiaires Iiifs. dc8. Euv. do Reims; Assoc. Fran;, jioiir IWvanc't ilcs Soiriices, IH^O, p. 15. CH DKISTODEEA. 1 07 Champsosaueus australis Cope. American Naturalist, 1861, p. 670 (July). Plate XXIIIlj; figs. 1-4. Eleven vertebrse, probably ofone individual, were found by Mr. Baldwin, mingled with jaw fragments, with teeth of the Eocene Mammal Catathlceus rhabdodon. All the pieces are enclosed in the black ferruginous matrix, in which the mammalia of the Puerco epoch are found embedded. The vertebrae, are of about the same size and form, and all belong to the dorsal series. Thej^ are characterized by their large width as compared with their depth, differing in this respect from all of the known species. The centra are regularly rounded below, and the borders are scarcely at all flared. One of the dorsals, probably an anterior one, has a prominent angular keel in the middle line below. The outline of the articular faces for the neural arches is pyriform, the wide portion concave, with its external edge decurved, and on the anterior half of the side of the centrum. The decurvature is sometimes sufficient to resemble part of a rib-facet. Articular faces of centra nearly plane. Sides of centra very little concave, a shallow fossa below the base of each diapophysis. Non-articular surfaces of centrum marked with a delicate thread-like sculjjture. and there is no coarse sculpture near the edges of the articular surfaces. Diameters of keeled dorsal centrum: anteroposterior M. .012; vertical .014; transverse .017. Diameters of a rounded dorsal: anteroposterior .013; vertical .012; transverse .015. The dorsal vertebrte are wider and more transverse than in either of the four known American species. They are longer than those of the C. vaccinsulensis, and lack the marginal wrinkles of the C. saponensis. From near Canyon Largo, San Juan River, New Mexico. Champsosaurus puercensis Cope. Proceeds. American Philosoph. Society, 1881, Dec. p. lO.") (1882). Paleontological Bnlletin No. 34, 1882, p. 195, Feb. 20. Plate XXIII ^3 ; figs. 5-10. This species is represented by a number of fragments, which include three dorsal and four caudal vertebrae of apparently one individual. They represent an animal of larger size than any of those heretofoi'e referred to Champsosaurus, excepting the C. vaccinsulensis. In all of the vertebrse the neural arch is more or less coossified with the centrum, and the animal had probably reached its full size. 108 THE WASATCH AND BUIDGER FAUN^. One of the dorsal centra is split vertically and longitudinally, and shows the structure already figured by Leidy in the Ischyrosaurus antiquus* Leidy. The surface exposed displays two diagonal lines of fissure crossing each other at right angles. They indicate clearly the mode of origin of this amphiplatyan type of centrum. The centrum is first deeply amphicoelous, as in the Theromorphous reptiles of the Permian. The conical cavities are filled by the ossification of the remaining portion of the notochord, forming a conical body which always remains • distinct from the remainder of the centrum. The articular faces of the dorsal centra are a little wider than deep, and the depth about equals the length of the body. They are not nearly so depressed as those of C. australis, and their outline is diff"erent. This is wider above and narrows below; in both C. australis and C. sajionensis the inferior outline is part of a circle. None of the dorsals preserved are keeled below. There is a fossa below the diapophysis which has a subvertical pos- terior boundary. The general surface (somewhat worn) does not display wrinkles near the articular faces. An anterior dorsal has a short compressed diapophysis with a narrow figure 8 articular surface, and its superior border in line with the roof of the neural canal. The anterior caudals have sub- round articular faces; the posterior are more oval, and the bodies com- pressed. With greater compression the length increases. Measurements. u. I anteroposterior 0-i5 Diameters of an anterior dorsal s vertical (hJ5 ( transverse 030 Heiffht of costal facet of do .'. 021 _. . , lit vertical 007 Diameters neural canal do. ( I transverse 009 / anieropoeterior 0"24 Uianieters anterior caudal < vertical 021 ( transverse 021 Santeropoaterior 025 vortical 018 transverse 018 The typical specimen was found by Mr. Baldwin near the Puerco River west of the Nacimiento Mountain, New Mexico, in the typical locality of the Puerco formation. •Trans. Auicr. Philog. Soo. 1860. CHOEISTODERA. 109 Champsosaurus saponensis Cope. Paleontological Bulletin No. 34, p. 196 ; Feb. 20, 1882. Proceedings Amer. Philos. Society, Dec. 1881, p. 196, 1882. Plate XXIII b ; figs. 11-22. Represented in my collection by six cervical and several dorsal verte- brae; one only of the latter with well preserved centrum, parts of ribs, and various other bones, whose reference is not yet certain. The cervical vertebrae include the os dentatum or centrum of the atlas. This shows its streptotylicate character in its distinctness from both the cen- trum and the free hypapophysis of the axis. Nevertheless, it is more Croc- odilian than Lacertilian in form. Its anterior face is transverse, with a little lip carrying forwards the floor of the neural canal, below which the face is bevelled posteriorly. The inferior surface is narrow and transverse, as though adapted for the anterior part of the hypapophysis of the axis. At each side it terminates in a prominent tuberosity, as though for the attach- ment of a cervical rib as in the Crocodilia. The anterior face is bounded posteriorly by a transverse groove which terminates in a down-looking fossa on each side. The i)osterior articular face of the os dentatum is wider than deep. The lateral angles of the superior face are rounded, and its median portion is concave. The axis displays a large facet for the hypapophysis. Behind it the infe- rior middle line is not keeled, but is coarsely wrinkled longitudinally. The posterior edge of the hypapophysial facet is the most prominent part of the inferior surface. The posterior articular face is deeper than wide. This is true of the faces of all the cervical vertebras. The latter gradually increase in size posteriorly, and the dorsals become larger. The articular faces of all the centra are regularly rounded and not contracted below. The five cervicals are strongly keeled below, the keel of the third centrum being split up anteriorly into narrow ridges On the sixth the keel is more prom- inent and acute. The dorsal is not keeled. A trace of the parapophysis appears low down on the fourth cervical ; it rises and becomes prominent as a rounded tuberosity on the fifth and sixth. It appears on the superior edge of the centrum of the dorsal vertebra, where it is connected with the diapophysis. It is near the middle of the length of the centrum, and not near the anterior border, as in C. australis. 110 TDE WASATCH AND BRIDGER FAUN^. The surfoees of tlie vertebra; are very smooth, excepting where thrown into coarse wrinkles near the border of the articular faces and near the hypapophysis. The edges of the articular faces are somewhat revolute on the sides in the cervicals, but not on the doi"sal. They are impressed in the centre to a point, most strongly so as we pass forward in the series. There is a fossa below the space anterior to the parapophysis of the dorsal verte- bra, which is abruptly bounded below by a horizontal angle. A separate neural spine, perhaps of a cervical vertebra, has the following form. It is stout and contracts rather abruptly at the apex from behind forwards. The section is broadly lenticular, angulate in front and truncate behind. The posterior foce has several longitudinal wrinkles, including a median raised line, and there are some more irregular wrinkles on the sides. Mea,surements of vertebra:, Autcriorface of os deutatum ^ width 025 4 depth (oblique) 012 Posterior face of 03 deutatam I ^^'*ltli 020 \ depth 018 Length 03 dentataiu above 014 (posterior face J *l''I'f'' ^^- Diamoters axis ^ < width 020 ( length 0185 Hypopopbvsial facet OS dentatuuJ ''''I'"' ^^ l width 014 ^. , . . , ( leUL'th 022 Diameters fourth cervical < , ■, ^^ n.v.= < anterior •^"Ptli ^^^ \ width 022 . , (length 0215 Diameters sixth cervical < ^ i .i i>.>i.- < anterior M«l"l^ ^^'' < wid vidth 02;i5 Space between parapophysis and diapophysis of do 0040 ^. _ _ , , , ( length t'2l)5 (pth O2G0 id(h 02C5 anierior . jd< ( w Height of neural spine of f from postliypapophysis "210 Anteroposterior width of do. at base 0100 The portions of ribs are separated heads and shafts. The former are doul)le and therefore cervical, and are quite large. If the shafts belong to them, tlie neck of this species must have been wide. The shafts are slender and of dense bone. The section is oval at the middle, but towards the dis- tal extremity becomes flattened and grooved, and delicately lined on one side. The extremities of the long bones are without condyles, but have concave surfaces like those of the ribs. The bodies are robust and angular. They may be abdominal ribs of unusual stoutness. From the Puerco beds. 1). Haldwin. rp TESTUDIXATA. Ill TESTUDIXATA. As the Eocene forms of this order are of unusual interest, I give an analysis of the extinct genera of the Cryptodire division, which have been found in North America and Europe up to the present time. In the check-list of the North American Batrachia and BeptUia,^ I enumerated nine families of this division of the Testudinata, three of which are extinct. Subsequently another extinct family, the Baenidse, was added. I now define all of these families. I. Plastrou uot articulated to tlie carapace, but presenting to it more or less open digitations. Dactylosterna. Phalanges of anterior limb without condyles, and covered by a common integument ; eight pairs of costal bones Cheloniida'. Phalanges of anterior limb without condyles ; nine or mtfre costal bones . Propleuridce. ' Phalanges of anterior limb with condyles ; digits inclosed in tlistinct integ- uments ; eight costal bones ; sternal elements united by digita- tions and inclosing fontanelles ; caudal vertebrae procoelous . Trionychidce. Phalanges of anterior limbs with condyles ; digits distinct ; eight costal bones ; .•sternal elements united by suture and mclosiug no fontanelles ; caudal vertebrae opisthocoelous Chelydridw. II. Plastrou uniting with the costal bones of the carapace by suture, with ascending axillary and inguuial buttresses. (Feet, ambulatory.) Clidosterna. A Intersternal bones present. No intergular scuta Pleurosternidce.\ Intergular scuta ; caudal vertebrae optisthocoelous . Baenidce. A A 'So intersternal bones. a Intergular scuta. A mesosternal bone . . Adocidce. a a Xo intergular scuta. A mesosternal bone ; three series of phalanges Emydidce. No mesosternal bone ; three series of phalanges Cinosternidce, A mesosternal bone ; two series of phalanges Testtidinidw. III. Plastron uniting with the marginal bones of the carapace by straight suture only. (Feet, ambulatory.) Lysosterna. No intersternal bone nor intergular scutum; a mesosternal bone and three series of phalanges Cistudinidce. The extinct species of the Cryptodira of this continent belong to eight of the above families. I give diagnoses of the genera to which they are referred. Names of existing genera are in Roman type. * Bulletin U. S. NatioDal Museum, No. 1, 1875. p. 16. t There are two genera of this family, neither of them yet found in America ; Pleurosiernum Ow. •vrith smooth shell, and Helochchjs Meyer, with 8culi)turod shell. 112 THE WASATCH AND BKLDGER FAUN.E. Cheloniid^. Postabdominal bone« distinct from each other. Chelouia Brong. Postabdominal bones united with each other l\v suture.. Puppigeru* Cope, Propleukid^ Cope.* Transactions of American Philo8oi>bical Society, xir, 1870, p. 235. Ten costal bones; tirst two marginals united with carapace by suture ; shell smooth, flattened Osteopygis Cope. Nine costal bones; flrst two marginals united to carapace by suture; shell sculptured ; a high dorsal keel Feritresitts Cope. Nine costal bones; one marginal united with carapace by suture; second by costal gomphosis; shell not keeled nor sculptured. Propleura Cope, t Nine costal bones; first united with carapace by suture; second without costal gomphosis ; shell not sculi)tured Catapleura Cope. t Nine costal bones ; marginals all free ; shell not sculptured Lytoloma Cope. TRiONTcnm^. a Surface of l>ones smooth. Postabdominal suture digitate Axestus Cope. a a Surface of bones sculptured. ,9 Sutures of plastron digitate. A dermal flap ])n)tecting posterior legs below ; marginal bones. . . . Emyda Gray. A dermal flap ; no marginal bones Cyclanosteus Peters. No dermal flap nor marginal bones; muzzle much abbreviated Chitm Gray. No dermal flap nor marginal bones; muzzle elongate Trionyx Geoflfr. y9 /9 Suture for post-abdominal coarsely serrate. Postabdominal recurved in front Plastomenus Cope. ClTKLYDRIDiE. a Bridges of plastron wide ; f caudal vertebrai. One row of marginal scuta; six pairs of scuta of the plastron Idiochelys Myr. One row of marginal scuta; scuta of i)la**tron ?not distinct IIydropelta\ Myr. a u Bridges of plastron very narrow. ft Carai)ace smooth, not sculptured. Two rows of marginal scuta ; five pairs of scuta of the plastron . . Macrochelys Gray. Oue row of marginals ; five pairs on plastron Chelydra Schw. One row of marginals ; four pairs of scuta on plastron . Claudius Cope. ;9 ji Carapace sculptured. One row of marginal bones Anostira Leidy. Baenid^. Cope, Annual Report U. S. Gool. Surv. Terrs., 1872 (1873) p. 621. Supramarginal scuta (lUitimeyer)and intormarginal scuta; no inter- humerals Platychelys Myr. No iiiterliuineral scnita; no sui)ramarginals Jiaena Leidy. luterhuiiieral S(;uta; no supramarginals .... . Polythorax\ Cope. 'J'ala-orhrlyf norimcuntiiliiH GeolTr. liclongs to tlii» family, Vint not Valaoihclys Mjr. \ EanfHtrmum WnKii. {I'aliromeduiia ct Acicluhif Myr. liili' Klilinieyer) is nearly allied to BydropfUa, t Povsi Illy one uf lliv AJocitUe ; see Proceed. Aca.aE. udinidae. Hydraspididse. Chelydridce. \ EmydidcB. Baenidte. Cheloniid^. Pbopleukid^. ADOCrD.^E. Sphargididce. Pbotostegid^. Trionychidte. / 116 THE WASATCH AND BKIDGEK FAUNiB. AXESTUS Cope. i»roceed. Amer. Pbilos. Soc, 1872 p. idi, (publiNLed July 29). Annual Report U. S. Gool. Surv. Terrs., 18/2 (lb7:!), p. 615. This is a genus of Trionychidae which is represented by a species not fully known. The type specimen is represented by bones of the limbs and various vertebrae, with the post-abdominal bone of the left side. The general characters are those of Trionyx. The scapula is elongate, the procoracoid long and narrow, and the coracoid of medium width. The humerus is sigmoid, with widely separated tuberosities, and flattened extrem- ity, with marginal groove. The femur is also curved, but less strongly than the humerus, and has a median anterior low angular ridge. The claws are large, some curved, and some entirely straight. The cervical vertebrae are relatively large and elongate. The two sacrals are free from the carapace above, have broad articular surfaces for diapophyses, and flattened centra. The caudals are procoelian, and have short diapophyses. The post-abdomi- nal bone has the form seen in existing Trionyx. It presents two dentate processes forwards for the hyposternal, and two inwards to its mate in front. It is prolonged backwards and inwards into a flat process. It is especially distinguished by its tenuity, and the entire absence of the superficial sculp- ture of Trionyx. The usual dense layer is present, but is quite thin, and exhibits the peculiar decussating pattern of lines of deposition character- istic of the same layer of the dermal scuta of Crocodilin. No portions were obtained which can with certainty be referred to the carapace. The ilium is short, stout, and recurved, and the pubis is largely expanded. AxESTUs BYssiNus Cope. Loc. cit. Plate XV, figs. 1-12. The procoracoid and scapula are of equal lengths, and the coracoid is much dilated distally. The portions of plastron preserved are thin for the size of the animal, and all the bones are especially dense and smooth. The post-abdominal has the free margins acute and serrulate. There is an external, gently convex edge, with a long process extending backwards; and one long narrow one inwards. The dense layer is marked with decussating lines of osseous TESTUDINATA. 117 deposits, as in woven linen The cervical vertebra is without spine; it is not depressed in the middle, and is without any pneumatic foramen. M. Length of cervical vertebra 0C8 Diameter at middle OiO Diameter at end 035 Diameter of caudal vertebra at ball 010 Length of caudal vertebra 023 Length of an ungual phalange 043 Proximal depth of an ungual phalange 013 Length of post-abdominal, broken 180 Width of post-abdominal 120 A hyposternal bone of a large Trionychoid turtle displays the charac- ters of this genus in its absence of superficial sculpture, and in the decus- sating bone structure of its borders and processes. It belongs to a species of the size of the A. byssinus, but is so much more massive than the post-ab- dominal bone of that species that I suspect that it belongs to a distinct one. Its median surface presents a few faint traces of tubercular roughening. Occasionally^ the supei-ficial layer of the bones of the plastron of species of Trionyx of this formation, are found nearly smooth, but they do not display the decussating bone structure, nor the thin edges of the species of Axestus It has often occurred to me that these peculiarities may be the result of erosion, and that the animals possessing them should be referred to the genus Trionyx. This may be the case, but there are two objections to such a view. First, the middle, or more prominent parts of the bone, where the attrition must be greatest, displays the characters least; second, if we imagine that movements of the limbs have caused the attrition, we are met by the fact that the decussating structures appear on the inner borders of the bones where the limbs do not reach. The typical specimen was found on Black's Fork of Green River; the second specimen on Upper Green River. TRIONYX Geoifr. Turtles of this genus were very abundant during the Eocene period in North America. They disappeai'ed from the interior basin with the close of this period and did not reappear ; but they continued on the Atlantic slope, and are to-day abundant in the tributaries of the Mississippi and in the streams that flow into the Gulf of Mexico. 118 THE WASATCn AND BKIDGER FAUN.E. Tliero were evidently several species of Trionyx during both the Wasatch and Bridger epochs ; but the specimens found are generally so fragmentary, that it is difficult to ascertain what characters can be relied on to distinguish them. In the Paleontology of New Mexico (Wheeler's Report) I enumerated five as occurring in the Wasatch formation of that region, but I am not sure that more than three of tliem will ultimately be found to deserve that distinction. In vay collection from the Bridger beds I have three manifestly distinct species, and I am compelled to admit two others. Of the five, I regard two as identical with New Mexican Wasatch species, and one as common to the Bridger and Wasatch beds of Wyoming. The proper definition of the doubtful species must be left to future discovery of better material. The Eocene Trionyches may be distinguished in tabular form as follows : I. Sculpture of the extremities of the costal bones thrown into ridpes. a Superficial layer of costal boues overhanging rib extremities. Eidges clo.se together T. lepiomitus. Eidges widely separated T. cariosits, a a Superficial layer of costal bones, sloping into free rib ends. Eidges widely separated T. raduln.i. Ridges do.se together, interrupted and vermiform .... T. ventricosux. II. Sulpture of the extremities of the costal boues honeycombed or punctate. Carapace with .seuljjture all honey-combed ; six vertebral bones ... T. vintaensis. Carapace covered with pits which are little wider than their inter- spaces ; seven vertebral bones T guttatm. Carapace with longitudinal ribs crossing the ends of the costals; pits small T. concent ricus. Carapace with longitudinal ribs along its middle ; seven vertebral bones ; pits not large T. heteroglyptua. III. Sculpture of extremities of costal bones, consisting of small tubercles formed of the broken ridges. Carapa<'<' honeycombed with large fossaj ; no ribs ; seven verte- bral bones T. sciitumantiquum. Tlie Wasatch species are : T. hptomitus, T. cariosits, T. radidus, T. ventricosus, T. guttatus, and T. scutxiinantiquum. The Bridger species are : T. radulus, T. uintaensis, T. guttatus, T. conccntricus, T. heteroglyptus, and T. scutuniantiquum. TESTUDINATA. 119 Trionyx radulus Cope. Systematic Catalogue of the Vertebrata of the Eocene of New Mexico; U. S. Geo. Geol. Expl. W. of 100th Mer., G. M. Wheeler, 1875, p. 3.5. Report Paleontology, do. iv. ii, p. 45. Plate xxvi, figs. 11-16. This turtle is nearly allied to the T. cariosus. As in it, the proximal portions of the costal bones and the vertebral bones are honeycombed, while the distal parts of the former are parallel-ribbed. Five to nine of these ribs can be counted from the free end. They are not closely placed, being narrower than their intervals. The size of the species is the same as that of T. cariosus, but the costal bones are more uniformly thinner. A specimen from the Bridger beds shows a rather wide, smooth band, along the front of the carapace. Measurements. K. Thickness at front of carapace at middle 010 Thickness of a costal bone at middle of border 006 Three ridges at end of costal in 010 I have but one specimen of this species, in many fragments, from the Bridger formation. Trionyx guttatus Leidy. Trimyx guttatus Leidy, Report U. S. Geol. Surv. Terrs. (4to), p. 176, pi. ix, fig. 1. Cope, Report Expl. Surv. W. of 100th Mer., G. M. Wheeler, iv. pt. ii,p. 46. T. uinlaensis Leidy, Cope, Syst. Catal. Vert. Eocene New Mexico, p. 35 (not of Leidy). This is the most abundant species of the Bridger formation, and I obtained parts of many individuals. Its characters are expressed in the definition already given. To it must be added that the distal ends of the costal bones are beveled regularly to the free rib-extremity. Almost the entire carapace of one of the individuals of this species was obtained by myself in New Mexico. The pitting is uniform and without interruption, extending even to the sutural edges of costal bones. It is strong on the vertebral bones, but, near the distal ends of the costals, becomes obscure ; the border itself being smooth. The ribs separating the pits are coarse, but not so wide as the pits. The posterior part of the carapace of a Bridger specimen has the last two pairs of costals in contact, showing that there were only six vertebral bones. The pits are rather small, having, in some places, interspaces as wide as themselves ; this is, however, not generally the case. The dividing 120 THE WASATCU AND liKlDGEU FAUN^. ridges are always wider and more obtuse than in T. scutumantiquum and T. uintaensia. I did not obtain the last-named species in Wyoming, so far as I know, and I refer to Dr. Leidy's work for a full description of it and of the T. guttatus. Trionyx heteroglyptus Cope. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. C16. Plate XVI, fig. 2. Carapace broad, flat, concavely truncate behind. Free portion of costal bones short. The last pair of costal bones are in contact by a common suture by about two-thirds their width, the anterior portion being separated by the last vertebral bone. There is a great diflference between the sculpture of the middle of the carapace and its lateral portions. The former region is coarsely ribbed longitudinally, the intervening grooves being mostly unin- terrupted. On the middle portions of the costals the ridges are more or less broken up, and distally they are very delicate, forming an inosculating pattern, inclosing small pits. On the last costal they retain their ridge-like character. The posterior vertebrals are marked by a single groove down their middle. Mea«uremenU. M. Width of (■■ara])ace at antepenultimate cost.al bone 235 Length from front of carapace at autepenultimato costal bone backwards 095 Width of car-ajHice at antepenult iniate costal distally 048 Length of last two vertebrals 037 This is a handsome species, and appears to be rare, as I have but two specimens that I can definitely refer to it. It is, however, difficult to dis- tinguish separated ends of costal bones from those of T. guttatus. I dug one of the specimens from the summit of the Church Butte, Wyoming. Trionyx concentricus Cope. Proceed. Amer. Philos. Soc, 1872, p. 469 (published July 29). Plate XVI, figs. 3-6. This species reposes on various fragments, in one case representing numerous poitions of a carapace. The sculpture is intermediate between those of T. hderoglyptm and T. guttatus. The costals have subequal and subruund pits throughout the entire length of the bones, but their inter- 8 o TESTUDIXATA. 121 spaces are raised into longitudinal ribs at intervals of from one to three rows of pits. These ribs are equally developed at both ends of the costals. Measurements. M. Width of a costal bone uear middle 020 Thickness of costal bone near middle 003 The type specimen is smaller than that of the last. From Cottonwood Creek, Wyoming. Trionyx scutumantiquum Cope. Annual Report U. S. Geo. Geol. Surv. Terrs. 1872 (1873), p. 617. Plate XVI, fig. 1. Established on a nearly perfect carapace and part of the plastron from the bad lands of Cottonwood Creek. These indicate the largest species of the genus yet found in North America. The carapace is a longitudinal oval, broadly rounded in front. The median line forms a marked depression, and the costal bones rise and descend again, forming an arch on each side. The free portion of the ribs is not very long The sculpture consists of numerous honeycomb-like pits separated by rather narrow ridges. On the middle parts of the carapace these are subequal, but on the middle of the length of the costals all the ridges run together longitudinally, and on their distal parts, these are broken up so as to produce innumerable irregular tubercles and pits. The lines of the intercostal sutures are smooth. Eight costal bones, and an anterior mar- ginal coossified with the first costal by its entire width, and sending out a broad costal extremity, which curves backwards, its anterior margin smooth. Eight vertebrals, the last separating the anterior portions of the last costals. Measurements. M. Length of carapace 425 Greatest width ot carapace, axial 410 Thickness of fifth costal 0075 Thickness of fourth vertebra 034 Thickness of centrum of vertebra 010 Several fragmentary individuals from the Wasatch beds, near Black Butte, Wyoming, as also one from the corresponding formation on Bear 122 THE WASATCn AND BlilDGEU FAUN^. River, resemble this species more nearly than any other. They display similarity in the fineness and acuteness of the ridges between the fossc-B, and their disposition to break into small tubercles on the distal parts of the costal bones. More perfect specimens will be neccessary to decide whether this species is common to the two horizons or not. PLASTOMENUS Cope. U. S. Geol. Surv. Terrs. 1872, p. G17. Ri-port Expl. Surv. W. 100th Mer., G. M. Whcolcr, iv, pt. li, p. 47, 1877. The structure of the skeleton in this genus remains incompletely known in spite of the abundance of specimens which I have procured in the Eocene beds of the West. As already stated, it is allied to the genus Trionyx, but differs in some important points in the bones of the plastron. The hyosternal bones which I have seen in P. multifoveattts are generally like those of Trio- )ii/x, while the hyposternals, if I have con-ectly identified them, differ mate- rially. These elements are preserved in the species named, and in P. cor- rugatus, and here they display a transverse width behind the inguinal region more like an Emydoid than a Trionychoid genus. The inguinal border is thickened, and at the bridge somewhat recurved. The inguinal buttress is in all three of the species more robust and more vertically directed than in Trionyx. The post-abdominal suture is closer and less digitate in the P. tri- onychoides. In P. corrugatus there is a fontanelle at the supposed post-ab- dominal suture, as in Trionyx, while there is no indication, of one in the P. trionychoides. The hyposternals also display a more completed ossification than in Trionyx, in the fullness of the borders between the internal and external digitations. Thus, in P. multifoveatus, the internal border is regu- larly convex, and the processes for the episternal bone scarcely project beyond it. The external digital process projects more extensively, while the free ends of the ribs extend little or not at all beyond the border of the caraj)ace. Among the various remains from AV'yoming and New Mexico, no marginal bones have been found, nor dermal scutal sutures. Portions of the skeletons of the species of this genus are very abund- ant in the Eocene of New Mexico and Wyoming. Though one seldom obtains an entire carapace or plastron, the form, size, and sculpture indicate TESTUDINATA. 123 that the remains belong to several species. The figures, composed of ridges, pits, etc., variously distributed, are often quite elegant. The species do not attain the average size of the Trionyches of the same era; but the P. com- munis, P. lachrymalis, and P. muUifoveatus exceed in dimensions the living species of that genus of North American waters. The three species above named, in which the sternal characters are evident, are the only ones which can certainly be referred to the genus ; but several others from the Eocene beds can with much probability be referred here also, the whole number being eight. Four species from the Fort Union Cretaceous beds have been referred to Plastomenus, but, as already remarked, as a provisional arrangement until their structure is bet- ter known. The P. thomasii is also of uncertain reference to this genus. J. Surface without welts, or with the sculpture thrown into ridges : a. No ridge-lines : Surface with sharp, fine wrinkles P. corrttgatns. Sui'face with more remote wrinkles, little inosculating P. trionychoides. Surface honeycombed with thick, inosculating ridges P. muUifoveatus. a a. Sculpture thrown into ridge-lines : Surface coarsely honeycombed with fine ridges P.fractus. II. Sculpture interrupted with solid welts; pits small or reduced to puuctfe: Surface with transverse ribs separated by one or two rows of pits P. scriaUs. Welts on all the thin costals, and separated by numerous pits P. molopinus. Welts only on the posterior costals, which are all thick; numerous punctfe between them P. comnumis. Welts broken up into short ridges behind ; intervening surface punctate. P. lachrymalis. Welts represented posteriorly by tubercles separated by smooth surface, anteriorly unbroken ; the surface punctate P. ademius. Of these species, P. corrugatus, P. muUifoveatus, P. fractus, P. seriaUs, P. communis, and P. lachrymalis have been found in the Wasatch beds of New Mexico ; and the P. trionychoides, P. muUifoveatus, P. molopinus, and P. cedemius in the Bridger beds of Wyoming. Plastomenus trionychoides Cope. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 619. Anostira trionychoides Cope, Proceed. Amcr. Philos. Soc., 1872, p. 461 (published July 29). Plate XVI, fig. 1. The original specimen of this species was found mingled with one of Anostira ornata, and being of about the same size, the two were supposed to pertain to a single species. -I subsequently distinguished the fi-aginents 124 THE WASATCH AND JJKIDGKR FAUNJE. ■clearly, and find portions of another individual from another locality to pertain to the same. The sculpture of the costal bones consists of reticulated ridges which inclose coarser pits than in the next species, and show no tendency to run into ribs extending obliquely acrossthe bones. The first costal exhibits a greatly beveled suture for the nuchal, and its alar portion behind its costal rib is twice as wide as the latter. The last costal differs from that of P. thomasii in being angulate instead of truncate at the rib-extremity, and the latter projects strongly beyond the angle. The sculpture of the costal bones is somewhat like that of Trionyx scu- tumantiquum. It can hardly be regarded as the young of that species, for, although of small size, the complete ossification of the costal bones indicates that the specimens are of mature age. Bad lands of Cottonwood Creek, near Fort Bridger, Wyoming. Pj.astomenus multifoveatus Cope. Anim.al Keport U. S. Geol.'Surv. Terra., lt<72(187.'?), p. G19. Report U. S. Geo. Geol. Siirv. W. of 100th Jlcr., iv, pt. ii, p. 49. P. thomasi p.irs. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. C18. Plate XVII, figs. 2-8. Represented by various parts of four individuals, a sufficient number of identical pieces being present in all to insure their specific unity. The bones of both carapace and plastron have a honeycomb pattern of reticu- lation, with shallow pits, which on weathering become punctaj. The intervening ribs tend to connect into ridges running diagonally across the costal bones. The pits tend to form linear series parallel to the bordei-s, on some of the bones of the plastron. The latter are gently convex at the transverse suture. The last costal is very wide, and is in contact with its fellow on the median line as in other species of the genus, except .a sutural margination behind, apparently for a pygal bone. The outer border is straight, truncating the last rib-extremity. Meaatircmcnts. M. Thickness of a costal 004 Wiillli luHt eostal, iliHtally 04(J Wiiltli of liyostemal 018 TliiikiH'HH of liyosternal 005 Lengt li of a vertebral 018 Width of a vertebral 014 TESTUDINATA. 125 Both the hyosternal and hyposternal bones are more convex than in any of the Triomjclies of the Eocene period. The ing'uinal edge is thinned, and is very gently concave. The hyosternal is much thicker on the outer part of its posterior suture than at the internal part Of course the same is true of the hyposternal. The latter is characterized by the steepness of the ascent of its external buttress, which is also situated neai-er to the hyosternal suture than in Trionyches generally. The external sculptured layer rises on its base and forms a narrow rim below the inguinal edge of the posterior part of the hyposternal for a short distance only. The pits of the inferior surface of the hyosternal are more or less parallel with the borders of that bone, while those of the hyposternal are irregular. In a costal bone of a large specimen, the sculpture is a shallow, but sharply impressed honeycomb pitting, smaller than in the preceding species Thus there are seventeen or eighteen pits across the middle, to seven or eight in P. trionychoides. No ribs whatever Measurements. M. Width of costal at middle 240 Width of costal at end 350 Thickness at middle 0035 I included the specimens of this species in my descriptions of P. tho- masiin the Annual Report of the United States Geological Survey for 1872. When I stated there that P. tJiomasi is the type of the genus Plastomenus, I referred to these specimens; it is therefore to be observed that the type of this genus is really the P. multifoveatiis The true P. thomasi was founded on. sternal bone perhaps of a small species of Trionyx. Some of the specimens of this species were found on Cottonwood Creek, Wyoming, and others on the Upper Green River. Plastomenus molopinus Cope. Annual Keport U. S. Ceol. Surv. Terrs., Hayden, 1872, p. 602. Anostira molopina Cope. Proceed. Amer. Philos. Soc, 1872, p. 461. Plaatomemis communis Cope, var. ii, Cope. Report Expl. Surv. W. of 100th Mer., Lieut. G. M. Wheeler, iv, pt,,ii, p. 50. Plate XVII, figs. 9-14. This tortoise was common in the Bridger epoch in Wyoming, and also in the Wasatch in New Mexico. My collection from the beds of the former includes eight individuals in a fragmentary condition. I have already men- 126 THE WASATCn AND BRIDGEIl FAUN^. tioned those from the latter horizon as a thin variety of P. communis, and figured some costal bones on Plate xxv, figs 5-G, of the Report of Lieutenant Wheeler, above quoted. It is probable that Dr. Leidy has figured part of a costal bone on Plate xvi, fig. 12, of the final Report of Dr. Hay den, vol. i. The costal bones of this species are generally ribbed towards the distal ends ; some of them at the proximal also. The ribs are not close together as in P. serialis, and their directions are somewhat irregularly transverse to the length of the costal bone. The sculpture of the surface between them is punctate rather than reticulate, since the impressed fossae are not wider tlian the intervals between them. The difference between this species and the P. communis is found in the much thinner bones of the carapace. A portion of the last costal bone of one of the specimens is without impressed jDunctae. Its ribs are thickened, and run parallel to the median line. Were they broken up into tubercles I would refer the specimen to P. cedemius. I do not possess the corresponding part in any other specimen. The size of the P. molopinus is about that of the P. cedemiits, and is less than that of my examples of P. muUifoveatus. Measurements. M. Width of a costal bone, proximally 018 Thickness of a costal hone, proximally 004 Width of another costal bone, distal ly 020 Width of the same costal bone, distally 003 The specimens are from various portions of the Bridger basin. Plastomenus cedemius Cope. Annu.-U Keport U. S. Geol. Surv. Terrs., 1872 ;1873), p. 619. Jnoitira ademia Cope. Proceed. Amor. Philos. Soc, 1872, p. 461 (July 29). Plate XVII, figs. 15-17. Represented by parts of three specimens. These all display the last and middle costals, and two of them the second costals. Sternal bones are wanting (except, perhaps, in one). From these it appears that the anterior costals have a distantly punctate sculpture, with rib-like swellings running diagonally across them. On the middle costals the punctae disappear and the ribs grow thicker ; on the last costals the ribs are broken into a number of smooth tuberculai* swellings whose axes are nearly at right angles to that of the carapace. The second TESTUDINATA. 127 costal has its posterior alar portion twice as wide as the rib portion ; its suture with the first costal is very oblique, and is bounded behind by a rab- bet-edge. The last costals are peculiar in their union throughout their entire length without emargination for pygal, and in the gently convex posterior outline (with projecting rib end), differing in these respects markedly from P. multifoveatus and P. trionycJwides. Measurements. No. 1. Length of last costal common suture 045 Length of last costal anterior suture 063 Length of last costal exterior horder 052 Width of middle costal 021 Thickness of middle costal 004 No. 2. Width of first costal, proximally 026 Width of first costal behind rib, distally 014 No. 3. Width of middle costal 021 This handsomely marked turtle is quite peculiar in its sculpture, which departs more from ordinary patterns than any of those referred to the present genus. Two specimens from Cottonwood Creek, Wyoming. ANOSTIRA Leidy. Proceedings of Academy of Natural Sciences, 1871, p. 102. In this genus the epidennis was thin and adherent to the bones, and not divided into scuta. The carapace is composed, as in Emydidce, of costal vertebral, and marginal bones, the last united to the first by suture and gomphosis. The series of vertebrals does not continue to the caudal except by the intervention of a pygal. The sternum is cruciform, with narrow longitudinal prolongations or lobes, and narrow bridges. It appears not to have possessed any fontanelles, but the presence of mesosternum is not yet fully made out. The cranium and limbs are unknown. This genus must be regarded as an interesting intermediate type con- necting Plastomenus and Chelydra or Dermatemys. In skin and sculpture it is identical with the first; in carapace and plastron most like Chelydra. Two species, a large and a small, are known. ilOM^ 128 THE WASATCH AND BRIDGEE FAUNiE. Anostira kaduuna Cope. Proceediogs Amcricau Fbiloeophical Society, 1872, p. 555 (published October 12). Plato XVII, figs. 18-19. Based on two marginal bones, one from the front the other from the rear of the carapace of an animal of twice the bulk of the largest Anostire previously found. Apart from size, the sculpture is peculiar. It consists in the anterior marginal costal bone, of closely packed vermicular ridges which run out flat on the posterior and upper edge. In the posterior, it consists of only closely placed minute tubercles over the whole surface, which are more or less confluent on the proximal part of the bone. Measurements. M. Length of front marginal on free edge 025 Width of front marginal on free edge OiS Length of posterior marginal on free edge 025 Width of posterior marginal on free edge 025 The specimen on which this species reposes cannot well be regarded as an overgrown A. ornata, since the sculpture of the bones is not enlarged in proportion to the size of the elements of the skeleton. The tubercles and ridges are not larger than those on a small A. ornata. One specimen from the Bridger bad lands of Hams Fork, Wyoming. Anostira ornata Leidy. Proceed. Acad. Phila., 1871, p. 102. Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 174. Plate ivi, figs. 1-6. This species has been so fully described by Leidy, that I only give a brief synopsis of its characters. The outline is a broad oval with an open emargination in front. The median dorsal line is keeled posteriorly, as far as the posterior border. The posterior marginal bones are thickened so as to have in part a triangular section. The margin is acute and not or but little recurved. The sculpture of the costal bones is in obsolete ridges running parallel with the middle line, and close together. That of the marginals is in small tubercles which run together at the proximal part of the bone above, and generally on the inferior surface. The branches of the plastron are all narrow, and the transverse ones TESTUDIISrATA. 129 quite long-. The external borders of the latter are coarsely dentate, but not digitate. The sculpture of the plastron is obsolete. The size of the Chelopus guttatus or Chysemys pidus of our streams. Specimens were found by myself and party on Cottonwood Creek, and on the Upper Green River, Wyoming. EMYS Brong. The species of the Eocene formation which have been referred to this genus are evidently members of the family Emydidce ; but owing to the absence of descriptions and specimens of the crania, it is not certain to which genus of the family they should be referred. As in similar eases in paleontology, they are retained in the genus Emys until reasons for distin- guishing them shall be discovered. As already remai-ked by Leidy, the species so referred, have left more numerous remains in the Bridger beds than those of any other genus. The same is true of the Green River and Wasatch formations, the genus Trionyx only having left more abundant traces in the latter. During my explora- tions in Wyoming, in 1872, I detected three species in the Wasatch and Green River beds, one in the Washakie, and four in the Bridger formation; in 1874 I obtained two species in the Wasatch strata. These species may be briefly distinguished in tabular form, as follows : I. The bridge sutures on not, or moderately, elevated axillary and in- guinal buttresses. a Dorsal line with projecting keel. Vertebral bones smaller, thicker U. polycypha. Vertebral bones larger, thinner; gular plates not reaching meso- sternal bone ; grooves moderate U. terrentris. Vertebral bones larger, thinner ; grooves very deep and wide .B. megaulax. a a No dorsal keel. i? Gular scuta not extending on mesosternum. • Bones massive, with lines of growth on some; costals swollen at proximal end of costal scuta U. testudinea. Bones thinner ; no lines of growth ; costal bones flat E. euthneta. yS ,3 Gular scuta extending on mesosternal bone. y Vertebral bones wide. Shell thin ; lip of plastron not very wide H. lativertebralis. ■f y Vertebral bones elongate. Shell thin, little arched ; vertebral scuta wide ; sutures of plastron straight ; its lip narrower B. vyomingensU 9 0 130 THE WASATCH AM) liKlDCiKK FAUN^. Shell rorv thick, little nnhed ; vertebral scuta wide; sutures of plas- trou straight ; its lip nurrow E. shaughnaigiana. Shell thiu, little arched; vertebral scuta wide; lip of plastron very wide . E. latilahiata. Shell thin coossified, much arched above ; sutures of plastron irreg- ular; vertebral scuta longer than in other species E. haydeni. II. Axillary and inguinal buttresses very i)roinineut. Shell thin, carapace convex, not keeled ; scutal sutures not deep E. septaria. The distribution of these species is as follows : Wasatch, Wyoming — £. tastudinea, E. evthneta, E. megaulax; New- Mexico — E. lativertehralis. Bridger, Wyoming — E. pohjcypha, E. terrestris, E. tvyomingensis, E. shaughnessiana, E. latilahiata, E. haydeni. Washakie — E. septaria. It is true that in many Emydidce the young stages are characterized by a dorsal carina and greater width of the dermal scutal grooves. Dr. Leidy has suggested * that the immature stages of Emys wyomingensis are repre- sented by certain keeled specimens in his possession ; and also states that the mesosternal bone is more elongate in such specimens than in the larger ones. I have suspected that the forms I have named, Emys pohjcypha and E. terrestris, might be the young of E. shaughnessiana and E. wyomingensis respectively, but I have not identified them on account of the lack of spec- imens displaying intermediate characters, and also because of the shorter gular scuta of E. terrestris. If the mesosternal bone is longer in the young than in the adult E. wyomingensis, it should bear more rather than less of the gular scuta. The Emys megaulax of the Wasatch beds presents the characters of immaturity in the low median keel and the deep and wide sutural grooves. It is much larger than either of the two species just named, and its bones are stout. It cannot be the young of its cotemporary E. euthneta, for that does not exceed it in size. I have parts of several individuals of both for comparison. It is true that in all three of the spe- cies presenting these characters of immaturity, the shells are, so far as known, without fontanelles, and that in the smallest, E. polycypha, the ver- tebral 1 nines are relatively the thickest. • Report U. S. Geol. Surv., i, p. 148. TESTUDINATA. 131 I have not included the E. cihoUensis (Cope Report Expl. Surv. W. of 100th Mer., Wheeler, iv, pt., ii, p. 57), as it may have been founded on a larger E. euthneta. Emys polycypha Cope. Annual Rejiort U. S. Geol. Surv. Terrs., Hayden, 1872, pp. 625, 630. Palaotheca polycypha Cope, Pjocecd. Amer. Philos. Soc, 1872, p. 463. Plate XVII, figs. 20-22. This species of tortoise is indicated by vertebral costal and marginal bones of very small individuals. These bones are, however, not only thoroughly ossified, but are very stout, indicating the adult age of the ani- mal. The deeply impressed scutal sutures, and heavy proportions, as well as the elevated carina of the carapace, indicate affinity with Cistudo or, perhaps Testudo. As a generic character, it may be noted that the vertebral bones are subquadrate, and support the neural canal without intervening lamina. The carina of the carapace is abruptly interrupted at intervals ; some- times with, sometimes without, a pair of pits, one on each side. The marginal bones are well secured and the scutal sutures are deeply impressed on them. Memurements. M. Length of vertebral bone 009 Width of vertebral bone 0085 Length of margiual bone 01 This is the last of the tortoises of the Bridger formation. Emys terrestkis Cope. Annual Report U. S. Geol. Surv. Terrs., Hayden, 1872, p. 629. PaUeotheca terrettrie, Cope, Proo. Amer. Philos. Soc, 1872, p. 464. Plate XVII, figs. 23-25. In this species and the following, the lip only is inclosed by the gular scuta, which only reach the apex of the mesosternal. In neither are the articulations of the bridge with the costals known. Represented by three individuals, one of which may be regarded as the type. They are all thinner than the P. polycypha, and larger, being about equal to the Aromo- chelys odoratus of our ponds. In the type specimen the carina of the vertebral bones is interrupted by a deep sutural groove, which is less pit-like than in P. polycypha. The bone itself is broader than long, being perhaps, from the hinder part of the 132 THE WASATCH AND BIMDGKK FAUX.E, carapace. The (.•hivicular (episternal) bone is preserved. It is character- ized by the considerable and abrupt projection of that part inclosed by the gular scutum, which resembles what is sometimes seen in Testudo. The edge of this i)art is entire and acute. The posterior part of the projection forms a step-like prominence behind, on the superior or inner face. The bone is almost as wide as long, and the niesosternal causes a very slight median truncation, but overlaps much on the inner side. The gular dermal suture does not reach it. Measurements. L«?ngih of vprtebrul bono 00t> Wiatli of vcrtoliral bone 018 Length of epistcmal 02 Wid'.h of cpisteraal (transverse to axis of body) 017 Width of a costal Oil Thickness proximally W^ In the second specimen, a strong groove is seen to bound the lip of the front lobe of the plastron. In it the marginal is seen to be stout, a little recurved, and sharp-edged. A vertebral differs from those of other species in being longer than wide. In a third individual the gular lip is not so prom- inent as in the type, and the mesosternal bone truncates the clavicular exten- sively, giving it thus a more elongate form. The gular scuta expand to its front margin. The marginal bone is stout and sharp-edged, and is not so deeply impressed by the dermal suture as in P. jwli/ci/pha. Emys megaulax Cope. Annual Report U. S. Geol. Surv. Terrs , 1872, p.628. E. pachylomus Cope, loc. cit., 629. Plate XVII, figs. 2G-33. Represented by remains of five or six specimens. They pertained to a species of about the size of the salt-marsh terrapin Malacockmmys palus- tris. The marked ptculiarity consists in the broad and abruptly sunken sutures which separate the dermal scuta of the carapace. This is visible on vertebral, costal, and marginal bones, where the area? between the sutures are abruptly separated. The sutures partially interrupt the dorsal carinn. This is wide and low. The surface is otherwise smooth. The scutal sutures are not so much impressed on the plastron, and those of the gular scutes extend on the mesosternal bone. TESTUDINATA. 133 Measurements. M. Length of a marginal 016 Width of a marginal 023 Width of a vertebral 018 Length of a vertebral 017 The vertebrals are subquadrate in fonn. Neither carapace or plastron are thick. The mesosternal is transversely diamond-shaped, and angular in front. Measurements of mesosternal. Length 023 Width 034 Other fragmentary specimens similar in size to the last, have the scutal sutures strongly marked, but not so widely and deeply impressed. Though they are finer, they interrupt the dorsal carina, which swells up from it, and they divide the flat proximal portion from the much swollen marginal part of the marginal bones. The mesosternal bone is similar in form to that of the last specimens; the only specimen is obtusely rounded in front, and bears part of the gular scuta. From the Wasatch or Green River beds at Black Buttes. A third but uncharacteristic series of fragments from the first Eocene lignite bed above the Cretaceous, probably belong to this species. Emys euthneta Cope. Annual Report U. S. Geol. Surv. Terrs., 1872, p. 628. Plate XVII, figs. 34-42. Represented by numerous portions of several specimens. These per- tained to a species of about the size of the salt-water terrapin, Malacoclemmys palustris. There is no dorsal keel, and the scutal sutures, though distinct, are not very much impressed nor the interspaces swollen. The lip of the plastron is narrow, thick, and not notched; the sutures of the gular scales do not extend on to the mesosternum. The margins of the lobes of the plastron are a little thickened and the sutures of the bones coarse and at the hypoxiphisternal junction, etc., with gomphosis. (It is fine and close at this point in E. testudinea.) The costal sutures for the bridge are projecting and curved, in one position; in the other, straighter, and very near the margin of the costal bone. Surfaces smooth. 134 THE WASATCH AND RKIDGER FAUN^. Abundant in the red beds wliich lie between tlinse identified as belong- ing to the Green River and Bridger epochs at Black Buttes, Wyoming. Emys testudinea Cope. AoDaal Report U. S. Geol. Snry. Terrs., Hayden, 1672, p. 627, Xotomorpha testudinea Cope. Proceed. Amer. Philos. See, 1872, p. 475. Plate XXIII, figs. 12-13. Represented by portions of four or more individuals. In one of these the anterior lobe of the plastron is in part preserved. The mesosternum is a transverse oval, the posterior margin regularly convex, the anterior with three equal borders. The median of these is concave. The sutui-es are radiating, and the groove separating the humeral scuta, appears to traverse the entire length of the bone. The outer surfoce is gently convex. The free margin of the episternal and hyposternal bones is acute, and with an internal thickening, as in Cisindo, Testudo, dr., forming a ridge with abrupt inner face. This face extends backwards as a groove, to the axillary process of the hyosternal, forming a characteristic mark. Although the extremity of the episternal bone is lost, and the mesosternal exhibits no trace of tiie intergular scute, the outer sutures of the gular scuta are so far posterior as to render it highly probable that the intergular plate existed. At the point where this suture reaches the margin, the latter is openly emarginate. The posterior suture of the humeral suture crosses the margin half way between the axilla and the episternal suture, and is not marked by a notch. The last-named suture is transverse. On the xiphisternal bones the groove of the anterior suture of the anals is plainly visible. It is regularly convex forwards, and in one specimen is double. In a second specimen of about the same size, parts of two costal bones are preserved They are thick, and display the usual costal and vertebral scute-sutures, the latter in a groove; for the middle of the vertebrals is ele- vated, and the costals project shoulder-like just outside the groove. In a third specimen a little larger, xiphisternals with several marginals are preserved. A free po.sterior marginal is regularly recurved, and the scute-sutures are deeply impressed. The margiiuil scuta have evidently been marked with concentric grooves within their margins. The first mar- ginal bone of the bridge has a very obtuse edge. In nono of the specimens are the surfaces sculptured. TESTUDINATA. 135 Measurements. No. 1. M. Width of plastron at axilla 086 Length of plastron from axilla (approximate) 05 Thickness of hyostemal at mesosternal 099 Thickness of hyostemal at hypostemal 0005 Width of mesosternal 037 Length of mesosternal ^ t 026 Thickness of a vertebral 006 Thickness of xiphisternal (normal) 004 Thickness of xiphisternal at pubis 007 No. 2. Thickness of costal at hump 0075 Width of costal 0175 No. 3. Width of posterior marginal 027 Length of posterior marginal 019 The mesosternal, though found with No. 1, does not fit it exactly and does not belong to it. From Green River formation near Evanston, Wyoming. Ejtts vyomingensis Leidy. Annual Report U. S. Geol. Surv. Terrs., Hayden, 1871, p. 367, Montana. Proc. Acad. Phila., 1869, p. 66. E. stevensonianus Leidy, loc. cit,, 1870, p. 5, fide Leidy. E. jeanesi Leidy, loc. cit., 1870, p. 123, fide Leidy. Plate XXIII, figs. 9-11. Of this, the most abundant tortoise of the Bridger Eocene, I obtained numerous specimens on my expedition of 1872. I refer especially to three as most characteristic, one a chelonite entire, but with plastron crushed in; a second broken up, but including portions of most of the shell; and, tliirdly, a nearly perfect plastron. These all show that the species had no intergular scute, as finally decided by Leidy. They also show that the notch on each side of the lip of the plastron is not uniformly present. As Dr. Leidy has given a very full account of this species, with good figures,* I do not redescribe it here, but refer to it in the descriptions of the allied species. Emys shaughnessiana sp. nov. Plate XXIII, figs. 3-6. I describe under this name a species, which is represented by the greater part of one individual in a dislocated condition. The separated elements are in excellent preservation, so that the characters can be readily ascertained. 'Report U. S. Geol. Surv. Terrs., i, 1873, p. 140. 136 THE WASATCH AJND BRIDGEB FAUNJE5. The species has the linear dimensions of the E. vyomingensis, and differs primarily in the much greater thickness of the bones of the carapace, especially of the vertebral bones. The plastron is thick, but does not so much exceed the corresponding parts of the thicker examples of E. vyoming- ensis. Another character is the great thickness of the costal parts of the axillary and inguinal buttresses. In an antero-posterior diameter they are twice as large as those of E. vyomingensis, but not more prominent trans- versely. The vertebral dermal scuta are a little longer than wide, and the lateral sutures are strongly bracket-shaped, while the anterior and posterior one present an angle forwards on the median line, thus differing from the sutures in E. haydeni. The vertebral bones are longer than wide anterior to the sixth; the latter, with the seventh, are wider. The costal capitula are quite weak. The posterior marginal bones are not recurved, and the anal is not notched, and its border is a little convex. The lateral and ante- rior marginals are not grooved nor recurved at the margin. The dermal grooves of the carapace are generally strong. The plastron is of elongate proportions as compared with the ordinary E. vyomingensis. The lip is moderately wide, and has a notch on each side, as in the species just named. The mesosternum is wider than long, and is marked anteriorly by the gular scuta. The humero-pectoral groove reaches but does not cross it posteriorly, in which it differs from that of most of the Bridger species. The smooth border of the anterior lobe of the plastron is very wide anteriorly; that of the posterior lobe is even wider at the posi- tion of the ranges of movement of the thigh, where it is bounded within by a sharp groove. The posterior notch is well marked but open. Tlie dermal sutures are straight and not sinuous, as in E. haydeni. Measurements. M. Length of carapace 380 Width of carapace at second costal bone 145 LenRlli of tliird vertebral bone 040 Width of third vertebral bone 025 ThickiicHM of third vcrtebrol bone 016 Length of seveuHi vertebral bono 023 Width of wventh vertebral bono 033 Thi('kllf^!w of w^venth vertebral bone OH Width of axillary buttress 018 Anterior lobe of plastron < . P^, ' " TESTUDINATA. 137 M. 106 axilla 144 Length of bridge 144 Posterior lobe of plastron J . ". . i 'ili^ ,a^ Width of anterior lip 0(58 There is a peculiarity in the form of the lip of the plastron of the specimen on which this species rests, which may be a specific character. Instead of having an abrupt lateral prominence and truncate or concave anterior border, its outline is regularly convex, onl)- interrupted by the notch, which is half way between the median and lateral gular sutures. I dedicate this species to my friend Arthur O'Shaughnessy, of the British* Museum, who has published a number of important papers on her- petological subjects. The specimen above described was found by myself on Cottonwood Creek, near Fort Bridger, Wyoming. Emys haydeni Leidy. Proceedings of the Philadelphia Academy, 1870, p. 123. Annual Report U. S. Geol. Surv. Terrs., 1871, p. see. JS. loyomingenBU Leidy, part Report U. S. Geol. Surv. Terrs., Hayden, i, p. 14, PI. ix, fig. 6. The central parts of the carapace and plastron of an Emys from Cotton- wood Creek, Wyoming, belong to a species distinct from the E. wyomingensis, as it appears to me, and agrees very nearly with the figure and description of the specimen on which Dr. Leidy established his E. liaydeni. In fact, the general appearance of the specimen is that of a Baena, a resemblance produced by the density of the tissue and general coossification of the parts as well as the fineness of the sutures where apparent. The species differs from the E. wyomingensis in the marked and regular convexity of the carapace, both longitudinally and transversely, resembling no little a portion of the shell of an egg. The dermal sutures are straighter and less undulating on the carapace. The vertebral scuta are relatively longer, and their borders are not bracket-shaped laterally, and are very little or not angulate before and behind. On the other hand the grooves of the plastron are irregular, crossing and recrossing the median line at various points. The humero-pectoral suture crosses the mesosternum well in ad- vance of its posterior border. 138 THE VVASATCU ANDBRIDGER FAUN^. The carapace is of moderate thickness, and the capitula are robust, much more so than in the E. shaughnessiana. The anterior marginals are robust; a posterior is much more thickened inferiorly, and is consequently more recurved than in E. sliaughnessiana, and displays narrower marginal scuta. Measurements. H. Lonpth of third vertcliral bono -.045 Widtb of third vert*3brul bono 0;«) I.iMiRlli of third vcrtcbr.il scute 080 Width of third vertebral scute 056 Thickness of third mar(;iiml bone on suture for second 021 Thickness of plastron at middle of hypostcrnal 017 Width of anterior lobe at axilla 140 This specimen resembles the one observed by Dr. Leidy, in having the fourth vertebral bone octagonal, a character I have not met with in any other species. EmYS LATILABIATUS Cope. Proceedings of American Philosophical Society, 1872, p. 471. Represented by a perfect specimen of a tortoise of a broadly oval form, and somewhat terrestrial habit. Its prominent characters are to be seen in the plastron, of which the posterior lobe is deeply bifurcate. The anterior lobe is peculiar in the unusual width of the lip-like projection of the clavic- ular ("episteinal") bone, which is twice as wide as in E. wyomingensis, and not prominent. Bones all smooth ; margins of lobes of plastron thickened. There are three scans, perhaps, of muscular insertions near the posterior margin of the plastron, one oval one opposite to each lobe, and one round one opposite to the notch. As compared with E. septarius this species has no such septa nor sculp- ture ; the emargination of the plastron is more open, and the lip much shorter and wider. ifeasurements. K. Len;;th of earn|iace 255 Width of carapace 2.')0 Width of lip of [ilastron 06 Depth of posterior notch 02 The temporary misplacement of the typical specimen of this species prevents my giving other than my original description. From near Black's Fork of Green River. TESTUDINATA. 139 Emys septaria Cope. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 625. Plate XVIII, figs. 9-13. Established on a nearly complete specimen of the size of Ptychemys rugosa. The carapace is rather thin and the sutures not obliterated. The vertebrae are sessile on the vertebral bones. The form is quite convex. The plastron is flat and rather stout. The mesosternum is rhombic, the longer angle anterior on the outer side, but posterior on the inner side. Its anterior angle is embraced by the gular scuta. The anterior lobe of the plastron is contracted near the axillae, and flared with a thin edge in front of it, then contracted to the rather narrow lip of the middle front. The posterior lobe is somewhat flared and has a wide beveled margin, and is deeply notched behind, the notch being close, and the lobes projecting. The surface is delicately sculptured with obsolete ridged lines across the axis of the costal bones. The vertebral region is somewhat swollen between the cross-sutures, which present an obtuse angle in the same direc- tion, both before and behind. The scuta are longer than wide, and have bracket-shaped outlines. The surface has the obsolete ridges, which diverge in every direction from the inlooking angle of one end, but are mostly longitudinal. In old specimens this delicate sculpture might become obsolete. Measurements. M. Length (Jf plastron 325 Width of plastron at groin 150 Width of lip 054 Length of lip OL'O Width of clavicular bone behind 041 Width of mesosternal, externally 058 Length of mesosternal, externally 045 Thickness of hyosternal behind 015 Length of vertebral scutum 072 Width of vertebral scutum 068 Width of a costal bone 029 Thickness of a costal bone 006 Found in the bad lands of the Washakie basin, on South Bitter Creek, by the writer. 140 THE WABATOU AM-) BHIDGEII FAUNuE. HADRIANUS Cope. Proceedings of the Aniericau Philosopbical Society, 1872, i>. 468. This genus resembles Testudo in form, but has two anal scuta, as in most Emydiddc. The claws are short and stout ; one ungual phalange is a long oval viewed from above, and is oval in section, with obtuse edges. The articular surface is subinferior. A cervical vertebra is of moderate length and has a very prominent anterior zygapophysis. The centrum presents two distinct convex articular surfaces anteriorly, and one trans- verse one behind. A sacral is free from the carapace above ; it presents two surbround articular cups posteriorly and outwardly ; the anterior are broken off. These characters are observed in a large specimen of H. corsoni. Hadrianus allabiatus Cope. Proceedings of the American Philospbical Society, 1872, p. 471. Plate XIII, iigs. 13-15. This large land tortoise differs from both the //. quadratus and the H. octonarius in the absence of the projecting lip of the anterior lobe of the plastron, which is thus simply truncate. The mesosternum is not cordate, but has much the shape of that of //. quadratus; that is, rhombic. The scutal sutures are dee])ly impressed. The plastron is strongly concave. Carapace without irregularities of the surface. Length eighteen inches. From the bad lands of Cottonwood Creek, Wyoming. Hadrianus octonarius Cope. Proceedings of the American Philosophical Society, 1872, p. 468. Phito XX. The //. octonarius is distinguished from its congeners as follows. It is of elongate form, strongly contracted at the bridges, but expanded and arched above the limbs. The carapace is very convex. The plastron has the posterior lobe emarginate rather tlian bifurcate, as seen in H. corsoni. Each projection represents a right-angled triangle rather than a wedge. The anterior lobe presents an elongate lip, which is expanded and slightly emarginate, at the end. The mesosternal bone is heart-shaped, the posterior emargination being widt; and not very deep. TESTUDI]S^ATA. 141 The anterior margin of the carapace is somewhat flared above the limbs. The nuchal scutum is very narrow transversely, but elongate. The cara- pace descends steeply and is incurved in the middle of the posterior margin. The superior portions of the anal scuta cover an ovate projection of the surface. Measurements. Length (below) 730 Width .at middle 4:17 Width .at hind limbs 525 This species is perhaps the largest of our extinct land tortoises, and is founded on a beautifully perfect male specimen from the bluffs of Cotton- wood Creek. Hadrianus corsoni Leidy. Geological Survey Montana, 1871, p. 365. Tistudo hadriaiius Cope, Proceed. Amer. Philos. Soc, 1872, p. 463. Sadrianiis qitadratits, loc. cit., p. 468. Indicated by several individuals, one nearly perfect, the others rep- resented by all parts of the skeleton. This proves the existence of a very massive species of the terrestrial genus Iladrianus. The plastron presents a short, wide lip in front, which is turned outwards, forming a strong angle with the plane of the upturned front of the lobe. This lobe is bordered by a thickening of the upper surface, which cuts off the basin from the lip, as a high ridge. The posterior lobe is deeply bifurcate, each post-abdomnal projecting as a triangle. There is a notch at the outer angle of the femoral scute. The hyposternal bone is generally thickened within the margin above, and an elevated ridge bounds the basin of the plastron behind, as anteriorly. The middle of the plastron is thin. The carapace is without marked keel or serrations. It is remarkable for its expanded and truncate anterior outline, which is nearly straight between two lateral obtuse angles, thus giving a quadrate outline when viewed from above or below. Length of carapace, "TSO — 20 inches, width ".630. The marginal scuta are nar- row, and there is a large nuchal plate. Abundant in the Bridger beds. 142 THE WASATCH AND BRIDGER FAUN^. DERMATEMYS Gray. Annals Mag. Nat. His., 1847, p. 60. Catal. Shield Reptiles British Musonm, 1855, p. 49. Baptcmy Leidy, Proceed. Acad. Phila., 1670, p. 4. Report U. S. Geol. Surv. Terra., i, 173, p. 157. This genus is similar to Emys in the structure of the carapace and plastron, except that the lobes of the latter are narrowed and shortened. The scuta are similar, excepting that there is a series of intermarginals on the bridge on each side. There are thirteen marginals on each side, those of the last pair in contact throughout. In a specimen of the extinct species of the Bridger, I tind a trace of an intergular scute, as is sometimes seen in D. berarcU now living in Mexico. Dermatemys vyomingensis Leidy. Baplemyi icyomtnjwtsi*, Report of the United Statos Geological Sun-ey of Territories, i, 1873, p. 157. Plates xii, and xv fig. C. This tortoise is not uncommon in the Bridger beds, but generally in a dislocated or fragmentary condition. It is readily distinguished as a species by the elevated keel of the posterior vertebral and pygal bones. The mesosternal is large and emydiform, and is not marked by the humero-pec- toral dermal suture. It is extensively occupied by the large gular scuta, which exceed in size those of any other species of the formation. The size rather exceeds that of the average Emys vyomingensis. The Wasatch species D. costilatus* Cope diflPers in having an obtuse keel on the costal bones, parallel with the median line of the carapace, as in Staurotypus tri- porcatm. NOTOMORPHA Cope. Proceedings of the American Philosophical Society, 1872, p. 474. This genus reposes on a clavicular or episternal bone, which gives characters not seen in any other genus known to me. The sutures are dis- tinct and fine, and the form of the mesosternum is emydoid. The gular scuta are small, and occupy an angular space between the large intergular and humeral, which are extensively in contact. It is uncertain whether there are two or only one intergular. The general characters of the other •H<^port Expl. and Siarv. \\ . 100th Mer., (J. M. Wh(-«ler, iv, pt. ii, p. b1. TESTUDINATA. 143 bones are those of the less aquatic types of the Emydes. It is hkely, as ah-eady remarked, that this genus belongs to the Adocidce. The following were the characters with which I commenced the origi- nal description of the genus: "The elements of the carapace and plastron are massive, and the former was well arched ; both exhibit well-defined grooves for the sutures of the dermal scuta. The mesosternum is broad ovate, and the bones of the plastron are united by immovable sutures. The elevated lateral processes of the hyo and hyposternal bones are not broad and unite by suture with the lower plate of the first and last bridge- marginal bones. They are thus recurved in both cases, but none of the ribs indicate any sutural union as is seen in various genera. The costal bones unite with the marginals by serrate suture. In one species a large intergular scutum has left its impression, the gulars being lateral and rather small. The anterior lobe of the plastron is emarginate." I then added that the pubis was united by suture with the post-ab- dominal (xiphisternal) bone, and inferred that the genus should, therefore, be referred to the Pleurodira. I subsequently became convinced that the bones showing this sutural union are really costals, bearing sutures for the buttresses, and that there is no evidence to show that the sutural union of the pubis and ischium which chai-acterizes the Pleurodira exists in this genus. At the same time, having doubts as to the homologies of the dermal scuta observed, I referred the species which displays the supposed intergular bone to Emys. While I believe this course to be the proper one in the case of one of the species {Emys testudinea) referred to Notomorpha, I now be- lieve that the characters displayed by the other species {N. gravis) justify the retention of the genus Notomorpha. The only species known to me was obtained from the Wasatch forma- tion of Wyoming. NOTOMOEPHA GRAVIS Cope. Proceed. Amer. Philos. Soc, 1872, p. 476. N. garmani loc. cit., p. 476. Emys gravis Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 626. Plate XXXIII, figs. 14-16. This species is known from a number of separated bones which were found together. It is probable that the pieces of carapace and plastron 144 THE WASATCH AND BKIDGER FAUNiB. belong to the same individual. The dermal sutural grooves are well marked. There is a large intergular scutum, which evidently encroached considerably on the mesosternal (a piece not preserved), and was probably subtriangular in shape. The gulars are reduced to triangular areas on the outer anterior angles, the suture with the humeral being in front of the middle point between the angle and the hyosternal suture. The margin is less distinctly emarginate at this suture than in Emys testudinea. The marginal bones belong to both bridge and free edge. They are all much thickened medially, but with thin proximal sutural margins. The free ones are Avell recurved, and with regular rather thickened margins. The bridge marginals have very obtuse margins, Their general massive- ness is in contrast to the thinness of the costals, of which there are numerous fragments. Portions of vertebral bones are intermediate in thickness. There is no thickening or ridge on each side of the vertebral scuta. The scutal grooves are everywhere well marked. The surface of the max-- ginals and episternal is obsoletely rugose, somewhat as in some species of Taphrosphys from the Cretaceous. The posterior marginal bones are stout and more thickened inferiorly than those of the E. vyommgensis and E. shaughnessiana, and are more re- curved. Measurements. M. Length of ppistenial (.approxiiii.ite) 04 Length from posterior suture (approximate) to gular scute 02 Thickness of episternal, behind CI 1 Length of a marginal bone 042 Width of same m.irgiunl bono 045 Thickness of same marginal bono Ol,"! Width of a bridgi--inarginal 04 Thicknetiss of a verbetrai 007 From the Wasatch beds of Wyoming, si.x miles north of Evanston, near Bear River. BAENA Leidy. Geological Survey Wyoming, 1870, p. :J67. Survey Montana, 1871, p. 368. Report U. S. Geol. Sorr. Terrs., Hayden, i, p. 160. Cope, Annual Ucport U. 8. Geol. Siirv. Terra., 1872 (1873), p. 621. Chit- tmium Leidy, Proceed. Acad. Thila., 1872, p. 162. This genus agree with the Adocidce* in the presence of intergular scuta and the absence of coossification of the ischium and pubis with the plastron, * Proceedings of the American Philosophicol Society, 1870, p. 547. TESTUDINATA. 145 but differs in the presence of an intersternal bone on each side, as in the Pleurodira. As generic characters it possesses two marginal intergular plates, which resemble the gulars of Emydidce. It has a series of inter- marginal scuta. The free lobes of the sternum are narrowed and shortened and the bridge is very wide. The dermal scuta are everywhere distinct. The mesosternal bone is in form between T-shaped and sagittate. The last pair of marginals, instead of being in contact, are separated by a wide emargination. The preceding characters were first noticed by Leidy. Another one appears in my specimens of B. arenosa, B. undata, and B. hebraica, which Dr. Leidy does not mention, viz, the presence of five costal scuta instead of four. The accessory one is anterior, and is taken from the usual first costal and first vertebral, both of which are contracted in consequence. Leidy's specimens are damaged in the region in question, and do not dis- play anything. The character is unique in the order Testudinata, unless it be found in the Platychelys of the European Jurassic, which is one of the Baenidx The afiinities of this genus are complex and interesting. It would be a pleurodire, but for the fact that the pelvis is not coossified with the plastron; nevertheless there are rudiments of this union in the form of a shallow pit on each side. The posterior or ischiadic is near the posterior end, and on the lateral mai-gin of the post-abdominal bone ; it is of a naiTow, oval form. The anterior is shallow and sublaterally impressed into the side of the upright septum which supports the carapace. Whether it received the pubis or not is uncertain. The double intergular scute is not found in any existing genus of Pleurodira, but exists in Tropidemys Riitim. of the Jurassic. The posterior margin of the carapace is excavated as in Chelydra, but the margin is more arched in this position. This form in Baena suggests the presence of a large tail, and the sen-ate margin of the carapace posteri- orly reminds one again of Chelydra. There ai-e in B. arenosa fourteen mar- ginal scuta without the nuchal; in Chelydra serpentina, as in Emydidce, but thirteen. There are prominent axillary and inguinal septa, as in some Emydidce^ 146 THE WASATCH AND T^UinGKK FADNiB. They are composed of the produced edges of two coossified costal bones, united with the ascending buttresses of the plastron. The affinities appear to be to Adocus on the one side and Hi/dra-npididie on the other, perhaps as descendant of the former and ancestor of the latter. It also possesses traces of the other relationships of Adocus, i e., to Dernia- temys, and more remotely to Chehjdra. Baena hebraica Cope. Baicna kehraica, Proceed. Amer. Philos. Soc, 1872, p. 463 (published July 29). Annual Report U. S. GeoL Sarv. Terrs., 1872, p. 621. Plate XIX, figs. 1-2. General form depressed and discoid, as wide as long. Bridge wider than long, but the length equal to the width of the bases of the sternal lobes. Anterior lobe longer than wide at the base, and narrowed at the extremity. The inguinal and axillary septa are very prominent. The edge of the carapace from the front to the inguinal region, is without emargina- tion. All the osseous elements are coossitied. The scuta are well distinguished. Tlie nuchal is very small and wider than long; the first marginal is shorter but more prominent. The second and third are larger but narrow; the fourth and fifth are wider, but the sixth widens by an inward projection of its border so as to meet the inter- costal suture between the second and third costal scuta. From this one to the ninth (as far as presei'ved) the inner margins are produced so far as to make the scuta nearly twice as wide as long when viewed from above. The first costal is small; its posterior border is curved. The first vertebral is pyriform, truncate in front. It is (perhaps abnormally) divided by a trans- verse suture into a quadrate anterior and cordate transverse posterior por- tion. The other vertebrals are somewhat longer than broad, and are sepa- rated by sutures convex anteriorly. The intermarginal scuta are all wider than long; their number is nor- mally four, but a narrow one is intercalated beliind the inguinal on one side. The longitudinal sutui-e of the scutes of the plastron is exceedingly tortuous, winding between points more than an imli apart. The gulars and intergulars ai'e transverse and bounded bv transverse sutures. They TESTUDINATA. 147 cross the median suture (which is straight ou the anterior lobe) some dis- tance apart. The humerals are long, and the humero-pectoral scutal suture is convex backwards, its extremities reaching the margin in front of the axillae. The anterior extremity of the anterior sternal lobe has a quadri- lobate outline. The surface is smooth except along the lines of intercostal sutures, where short grooves parallel to the general axis alternate with protuberances having the same direction, the whole having somewhat the appearance of sculptured characters. Measurements. ML Length of carapace (axial) (19 inclies).. .500 Widtli of carapace (axial) (19 inches).. .500 Length of plastron from groin 295 Width of base of anterior lobe 1,55 Width of extremity of anterior lobe (at gulars) 080 Length of anterior lobe (at gulars) 123 Width of nnchal scute Oil Length of nuchal scute 024 Length of third marginal 038 Width of third marginal 015 Width of eighth marginal , 090 Length of eighth marginal 063 This species, when compared with its nearest ally, B. undata, diifers in the greatly wider marginal scuta; in the latter the corresponding ones (6-7-8-9) are much longer than wide, as in most other tortoises. The intermarginal scuta are of more elongate form, and the normal number is five in B. undata instead of four. The sculpture in the longer known species is entirely distinct, consisting of pits and tubercles scattered gener- ally over the surface; while the peculiar sculpture of the suture lines is wanting. B. liebratca is relatively wider. Bad lands of Cottonwood Creek, S. W. Wyoming. BAiiNA UNDATA Lcidy. Annual Report U. S. Geol. Surv. Montana, 1871, p. 369. Cope, Annual Report U. S. Geol. Surv. Terrs., 1872, p. 622. Chistemum undatum Leidy, Report U. S. Geol. Surv. 1, p. 169, pi. xiv. Plate XIX, figs. 3-5. A specimen of this species presents the following characters: The anterior lobe of the plastron is as wide as that of B. hehraica, but little more 148 THE WASATCH AND BRIDGER FAUN^. than half as long. Tlie posterior lobe is truncate at the extremity. The nuchal scute projects beyond the first marginal ; the reverse is the case in the type of B. hebraka. The posterior sutures of the intergular and gular scuta have a common center, and that of the gular has a rectangular curva- ture, the nearly transverse middle portion slightly convex forwards. The suture separating the femoral and anal scuta is similar, but reversed in direction, presenting two obtuse right angles, two portions being transverse and one longitudinal on each side. The Baiina undata is quite similar to the B. arenosa in most respects. As in Leidy's specimens, the sutures of the plastron in the B. arenosa are obliter- ated in my single specimen, while in several of the B. undata they leave distinct traces even when coossified. As the latter are of larger size than the former, the diflference in this respect cannot be due to age. Besides, the plastron is smoother and presents no median carina. It is more roughened posteriorly with small irregular tubei'cular ridges. Traces of the grooves seen in B. arenosa are found on the anterior median region. The peculiar fifth or anterior costal scute is similar to that of B. arenosa, as are the gular and intergular scutes. In fact, the resemblances between this species and the B. arenosa are so close that I suspect that when we come to know the younger stages of the latter we will find that the intersternal bones are present, as in the B. undata. On this ground I have not adapted the genus Chisternum proposed by Dr. Leidy for the latter on account of the presence of the intersternals. Baena undata is more abundant in the Bridger beds than any other species of the genus. I found it on Black's Fork and elsewhere. Baena arenosa Leidy. Proceed. Acuo., 1872, j). .''>r>4 (October 12). Diplo- cynodm suhulatiii Copi', Annual Kriiort U. S. Geol. Surv. T«>rre., F. V. Hayilen iu ch.'irgf, ls72 (1873), p. 6i:t. Plato XXIV, figs. 5-19. Some of the cervical vertebrae without hypapophyses. Their cups round, with smooth bordering surface of the sides of the centrum. The jaws only are preserved from the cranium ; the premaxillary is strongly CROCODILIA. 153 pitted, but the dentaiy has remote shallow pits on the outer face, and shal- low grooves below. Dentition very characteristic. There are two very long canine-like teeth in the premaxillary bone near its posterior margin, directed somewhat backwards ; these are preceded, after a space, by a medium-sized tooth, which, after a similar space, is preceded by another long tooth. Ante- rior to this the alveoli are lost. Two very long, smooth, compressed straight teeth in the front of the ramus mandibuli. These are followed abruptly by a distantly set series of subequal teeth of not one-fourth the size, vary- ing little to the back of the jaw. All the long teeth have subcompressed crowns with opposed cutting edges, and are smooth except at their bases. These are sulcata with wide grooves, the separating ridges being acute. The smaller teeth are cones with cutting edges. There are fourteen alveoli and one pit in the dentary bone from the posterior end to the beginning of the short symphysis. Measurements. M. Length of alveolar series to beginniug of symphysis 130 Diameter of alveolus of seventh tooth 008 Elevation of eighth tooth 017 Diameter of eighth tooth at base 0065 Depth of dentary at base 025 Elevation of first lower cauiue 018 Length of crown of second upper cauiue 017 Diameter of crowu at base 007 Length of third cervical (with ball) 037 Diameter of cup, vertical 016 Diameter of cup, transverse . 018 Length of a posterior dorsal 041 Diameter of cup, transverse 026 Diameter of cup, vertical 022 Found on the bluffs of the Upper Grreen River, of the Bridger epoch. This species agrees in some respects with the very brief description given by Marsh for his Crocodilus liodon. He does not mention the fluting of the base of the crown so remarkable in this species ; and states the ver- tebrge to be "strongly rugose" near the extremity, a character not seen in the present animal. The Crocodilus suhulatus was about as large as the Mississippi alligator 154 THK WASATCH AND BUIDGEU FAUN^. Crocouilus polyodon Cope. Dijilocynodut polyodon Cope, Annual Report U. S. Geol. Surv. Terrs., F. V. Haydcn iu charge, 1872 (1873), p. til4. Plate XX^^^ figs. 1-2. Represented by portions of cranium and teeth, with probably some vertebrae found close to them. This crocodile is similar in size to the G. subulatus or our existing alligator. It differs much from the last in the arrangement of the teeth. There is one prominently lai-ge canine opposite the symphysis (in C. suhidatus this tooth is opposite the posterior end of the same), which is followed by nine very small teeth, whose round alveoli are only separated by very thin walls. Following the last of these immediately, is another very large tooth, with nearly round alveolus, which is closely succeeded by other smaller teeth of larger size than those in fi-ont of it, and not differing in this respect among themselves. The crowns of the teeth are cylindric at the base, and have a double ridge on the anterior outer aspect. The enamel is obsoletely nigose striate at the base. The external surface of the dentary bone is deeply and coarsely pitted ; at its anterior part the pits are close, deep, and small ; on the inferior face they are deep short grooves. There is a seines of close small foramina along the inner side of the alveoli. Measurements. M. Depth of symphysiii 014 Diameter of "anterior canine tooth" 008 Distance of same from median " canine" 030 Depth of dentary hone at latter 027 Width of ramus at anterior canine 025 This species differs in many respects from the one last described. The teeth anteriorly are much more closely placed, and the anterior and middle canines are less separated, and more numerous small teeth occupy the interval. The splenial bone has a larger share in the symphysis, and the sculpture is much more profound. The teeth are not fluted. The type specimen was found on the bluffs of Upper Green River by the writer. Crocodilus ackr Cope. Plato XXIII, figa. 1-2. This species is represented by a perfect skull wliicli Inoks the lower jaw. In its general form this skull resembles the existing Crocodilus acutus, CROCODILIA. 155 and is narrower than the C. elliottii and C. affinis. It belongs with the latter in the group with robust frontal bone with strong lateral ridges. The top of the muzzle is absolutely flat, transversely and longitudinally. In this respect it differs from the C. americanus, which is characterized by the presence of a strong convexity of the posterior part of the nasal bones, and the parts adjoining. The table of the skull is wider than long ; the orbits are convex inwards but not regularly, so that the outline of the inter- orbital part of the frontal bone contracts forwards. Anteriorly the orbits are angulate by the union of two oblique borders, the malar and prefrontal. The angle which is in the lachrymal bone, is continued as a shallow gutter for a short distance forwards. There are no crests on the head. The anterior extremities of the nasal bones are prolonged a short distance into the external nares. The jDostero-external angle of the squamosal bone is compressed. The undulation of the superior alveolar line is moderate, The external edge of the pterygoid bone is thickened and truncate. A considerable triangular area of the supraoccipital bone appears on the superior face of the skull. The premaxillary bone measured to its posterior apex, enters the length to the extremity of the quadrate bone, three and two-thirds times, or a little more than three times, to the posterior border of the cranial table. The palatine bones extend very little beyond the anterior boi'der of the inferior orbital openings, a character in which the O. acer resembles the C. affinis, and differs from the C. americanus* The pitting of the surface of the skull is strongly marked everywhere, except on a very small space at the junction of the frontal and nasal bones. Five pits may be counted across the middle of the interorbital front of the frontal bone. On this bone they are subround and not deep nor confluent, but are separated by ridges narrower than themselves. There are five premaxillary and thirteen maxillary teeth on each side. They present characters which readily distinguish them from those of any other species known to me. Their sizes are graduated, and the larger ones do not present an abrupt contrast of size, as in C. jiolyodon. Their ci'owns are all more or less compressed, and have distinct acute cutting edges. The compression is most marked on the last six of the maxillary * For fine specimens of this species I am indebted to the Smithsonian Institution at Washington. 156 THE AVASATCFI AND lUMOGER FAUN^. fieries, and the last four are short lancet-shaped. The crowns anteriorly are long and acute, but they begin to shorten with the fifth maxillary and diminish regularly posteriorly. Tlie basal portion of a fully protruded crown is smooth; the greater portion is, however, longitudinally grooved. There are eight ridges on the narrower and ten on the larger teeth. The grooves are not so deep, nor the ridges as acute as in C. sulciferus Cope, of the Bridger beds, and the crowns are less robust and not so incurved. The teeth of the present species have more acute edges. On these grounds I have been obliged to regard the C. acer as distinct from the C. sulciferus. Measurements. M. Length of skull to line of extremities of qnadiates ;i90 Leiii;lli of skull to posterior border of cranial table 345 Longlb of skull to line of anterior border of orbit 238 Width of preniaxiUary bones 060 Width at preuiaxillary notch 046 Width at fifth maxillary tooth 072 Width at anterior angle of orbits 058 AVidtli at posterior border of quadrates 19-J Width of iuterorbital space 021 '-mi., .■ L ■ ^ -ut , < tt'i'iporal foss.-B 090 Width of po8t of dorsal ] The skull of the second specimen has a resemblance in general to that of the Crocodilus affinis, but differs materially. The three most prominent points of distinction are the following : There is no distinct transverse ledge of the frontal bone between the orbits, and the space between the anterior parts of the latter is honey-combed like the posterior frontal region, and not smooth. Secondly, the posterior part of the squamosal bone, where it CEOCODILIA. 159 rests on the quadrate, is broadly truncate, instead of acuminate, and its postero-interior surface is subhorizontal, instead of vertical. Thirdly, the basal part of the angular process of the mandible is expanded inwards into a shelf with convex border. One or the other, particularly the first and second, of these characters have been verified on several individuals of the C. affinis. The general form of the cranium is much like that of the wider forms of the Crocodilus americanus. The front and top of muzzle are flat, and thei'e ai-e no crests or ridges on either. The maxillary border is strongly convex to the position of the posterior canine tooth, and is deeply notched to accommodate the inferior canine. The muzzle is shortened in fi-ont of the nares, since the premaxillary border descends steeply from their ante- rior margin. In consequence of the mature age of the individual, the sutures of the skull are obliterated. The united nasal bones project into the nareal opening for about one-third the long diameter. The orbits are somewhat narrowed by the convexity of the internal border of the malar bones. The interorbital space is plane, of course, excepting the sculpture, but there is a slight tendency to a transverse ridge about opposite the mid- dle of the orbits. The superior border of the quadrate condyle is deeply notched near the middle, to receive a corresponding angle of the mandible. The projecting angular process is very wide at the base, its superior surface having two concavities, of which the inner is nearly twice as wide as the external. The inner convex border contracts rapidly distally, leaving the obtuse free end a little wider than long, and directed inwards. The sculpture is roughly honeycombed on the superior surfaces, especially on the squamosal, post-frontal, frontal, and top of muzzle. On the middle line, posterior to the middle of the latter, the sculpture is reduced to a few longitudinal grooves, closely placed. The pits are much smaller on the borders of the maxillary and front of the maxillary. The rami of the mandible have longitudinal grooves on the external sides, and the anterior part of the chin has small pits. The symphysis of the mandible is like that of C. affinis, somewhat elongate for this genus, and produced and rather narrowed to the apex. The rami separate opposite the second tooth behind the notch of the upper 160 THE AVASATCn AND BRIDGER FAUN^. jaw. The lateral posterior foramen terminates anteriorly opposite the pos- terior border of the orbit. The anterior border of the palatine orbital foramen marks the posterior third of the distance between the orbit and external nares, on the top of the skull. The posterior border marks the posterior edge of the orbit. The pterygoid bones are produced and present backwards an acute external angle. The posterior nai-es are well behind the posterior border of the orbital foramina. The palatine bones are nar- rowed posteriorly between the orbito-palatine foramina, being at the middle of the latter, a little narrower than either foramen. The posterior maxilhuy and mandibular teeth are concealed in the specimen, owing to the closure of the jaws. There are four teeth in the maxillary between the canine and the notch for the lower canine. In front of the latter, in the maxillary bone, there are five teeth, of which the third and fourth, counting from the front, are largest. The teeth are all sepa- rated by short interspaces, and are graduated in sizes, the large teeth not being abruptly larger, as in C. polyodon. The crowns are robust, and with round section at the base. They have a low cutting edge \n front and rear. The enamel is roughened by numerous short crowded filiform ridges, as in many other crocodiles, which are worn off in old crowns. MeasuremenU of skull. H. Total length with angles of mandible 700 Length on superior surface ; parietal bono estimated .'>.30 Width between external angles of quadrates 300 Width at orbits 230 Width at superior canines lt>3 Width at superior notch 01'5 Widtli at middle of nares 130 Width between orbits 050 Width of nares 047 Length from end of muzzle to orbit 360 Length from end of muzzle to lino of canine 180 Length from end of muzzle to line of notch 100 Diameter of canine tooth at base 020 Length of symphysis maudibuli 115 Tlie ouly difference to be noted between the fragments of the upper jaw of the type specimen and the corresponding parts of this one, is to be seen in the premaxillary teeth. In the former they are larger and are not separated by as distinct interspaces; the third and fourth appear to have CROCODILIA. 161 been in contact. While the form of the symphysis of the mandible is the same in both, the ramus of the type is stouter. The vertebrae are mostly injured. A cervical has a simple anterior hypapophysis with a concavity on each side of its base, and an obtuse keel on the middle line behind it. The ball is nearly round, and is bounded by a strong shoulder. The external slope of this shoulder is marked by a few ridges, and by considerable rugosity at the base of the neural arch. In a dorsal, the ball is a little deeper than wide, and the middle line behind the hypapophysis is a keel. The ball of a lumbar is wider than deep, and the external border surface of its shoulder, as well as that of the cup, are rough with short ridges. The first caudal has a robust diapophysis, and a fossa on the median line below. The chevron facets are large. Measurements of vertebra:. M. Length of a cervical 160 Diameters of base of ball ^^'''^^'^='1 " ^^ c transverse 033 Length of a lumbar 061 Diameters of a lumbar^ vertical 0:J2 ( transverse 041 Length of first caudal 060 vertical 030 transverse 028 Diameters of ball < The right half of the pelvis is preserved, wanting the distal extremities of the pubis and ischium. It has the typical crocodilian character of the perforation of the acetabulum open anteriorly by the failure of contact between the pubis and ilium. The ilium is much like that of the Missis- sippi alligator, so much so as to render description superfluous. Measurements of pelvis. Length of ilium ". 160 Depth of ilium 092 Width of contact with ischium 035 Width of ischium at base 080 Width of ischium at middle 033 Width of pubis at base 040 Width of pnbisat middle 019 Two dermal bones preserved are probably from the lateral dorsal region, although this is not certain. One of them is large, the other small; both are oval in shape, the larger rather narrowly so, and neither have a dis- 162 THE WASATCH AND BUIDGER FAUNiB. tinct keel. Both have a slight median elevation in the short diameter. The fossae are rather far apart; edges smooth. Length of the larger "".085: width .045. There are traces of the sutures of the neural arches of the lumbar verte- brae, showing that the individual was adult, but not aged, at the time of death The only species with which the present one can be confused, is the C. aptus Leidy, which was founded on a cervical vertebra from South Bitter Creek, "Wyoming. In that locality the beds of the Wasatch and Green River formation occur, and probably the Bridger; those of the Washakie group are not mauA', perhaps fifteen miles distant. This vertebra belongs, according to Leidy, to the cervical series of an adult animal, and measures only 16 lines long. A vertebra of the C. clavis, which must coiTespond in position very nearly with the one described by Leidy, measures 27 lines in length, and is therefore between half as long again and twice as long. This indicates an animal of so much greater size as to render their specific iden- tity highly improbable. A crocodile occurs in the Washakie beds with the C. clavis, of which I possess a fragmentary skull. It is of a size appropriate to the vertebra typical of C. aptus. Crocodilus affinis Marsh. American Jouraal of Science and Arte, 1871, June. Plate XXI, figs. 1-3. This is the most abundant species of tlie beds of the Bridger basin. I took a nearly complete cranium with some vertebrae from a bad land bluft' on Smith's Fork of Green River; and my friend George Wilson, of Chey- enne, Wyoming, presented me with a considerable part of the skeletons of two individuals, including two nearly complete skulls from the Church Buttes. Fragments of others were found by various members of my party on Black's and Ham's Forks of Green River. I have pointed out the characters which distinguish this species from the C. clavis. Under the description of C. elliotii, Dr. Leidy loc. cit., has given a pretty full description of another near ally, so far as his material permitted. One readily observes that the frontal and j)arietul regions of the skulls CEOCODILIA. 163 of this species are less rugose than those of the C. davis, especially in the plane in front of the interorbital ledge. It is there absolutely smooth. Posterior to the bridge, the fossas ai'e frequently no wider than their inter- spaces, which is not the case in C. davis. The middle line of the posterior half of the muzzle is nearly smooth. The sculpture of the malar bones is very strong, and that of the superior middle of the maxillaries nearly as much so; that of the lower jaw is distinct. The form of the skull is Avedge-shaped, and it is flat above, without keels or crests. The "interorbital ledge" is an abrupt change of level, with an outline concave forwards. It is somewhat like the corresponding locality in the existing jacares of South America. The extremity of the premaxillary drops off abruptly from the nares. The outline of the upper jaw is sinuous; the orbits are vertical in direction. The posterior part of th« squamosal bone is narrow, with nearlj? vertical interno-posterior side, and acuminate extremity. The posterior edge of the quadrate condyle is emarginate. The angular process is rather narrow, and is obtusely rounded at the extremity. The lateral mandibular foramen extends as far forwards as the line of the middle of the orbit. The symphysis of the lower jaw is of medium length, reaching the seventh tooth from the front. The chin is wedge-shaped. The teeth of the upper jaw are : premaxillary, 5 ; maxillary, 4, the canine, and 11. The anterior teeth are elongate conic, with somewhat compressed crowns, and weak fore-and-aft cutting-edges ; the posterior ones have very short ci'owns. The enamel is finely and roughly striate. In the mandible the first tooth is larger than the two succeeding; the fourth is the very large canine; those following the canine have about half its diameter. In this part of the dentition the C. affinis is like the C. davis. The sutures are well preserved in one of the crania. The posterior part of the parietal is nearly as wide as that of the frontal. The anterior part of the latter is much produced between the prefrontals. The nasals extend backwards behind the apices of the prefrontals and lachrymals, and are continued forwards as an acute process into the external nostrils to the third of their long diameter, as in C. davis. 164 TOE WASATCH AND PRIDCKU FAUNiE. Meagurementu of skuU. M. Leugth to anf^les of mandible 500 Length to posterior iKtrdcr of iiarietals 370 Willi 1) hcuvteii cxtiTiial angles of (juutlrates 218 Width af orbits 180 Width of supeiior caniues 1'20 Width (if .su]iorior notch 060 Width of iiiiddle of nares 085 Width between orbits 033 Width of nares 030 Length from end of mozzlo to orbit ;ioO Length from end of muzzle to canine 120 Length from end of muzzle to notch 0G9 Diameter of canine tooth at base 015 Length of symphysis mamlibuli 080 The vertebrse preserved are five lumbars; four with centra nearly com- plete. They have nearly round cups, and the shoulder at the base of the ball is not so prominent as in the lumbars of C. clavis described. The edge of this and of the cup, is marked with distinct short longitudinal ridg'es. What characterizes these vertebrje as diflPerent from the lumbars of C. clavis is the presence of a wide open groove of the inferior median line of the centrum. The sides bounding these grooves are regularly rounded and not angulated. This fact, with the absence of chevron facets, satisfies me that these vertebrae are not caudals, which are always grooved below. Measurements of a lumbar vertebra. M. Length of centrum, including ball 041 _,. . , < vertical 022 Diameters of cup < . ^^ ( transverse 022 Elevation with neural spine 063 Expanse of prezygapojdiyses 049 In some of these lumbars the neurapophysial suture is obliterated, indicating the maturity of the individual. Professor Marsh distinguishes his C. affinis from the C. elliotti of Leidy by the shorter premaxillary bones and a few other characters. I find my crania to agree nearly with the former in the characters in question Crocodilus hetkrodox Cope. Sygtemotic Catalogue Vertebrata, Eocene of New Mexico; U. S. G. G. Survey W. 100 Mer., by G. M. Wheeler, 1^75, p. 34. Alligator hclcrodon Cope, Prooced. Amer. Philos. Soc. 1872, p. 544. Annual Report U. S. Geol. Snrv. Terrs., F. V. Ilayden, 1872 (1873), p. (il4. Plate XXIV, ligs. 11-18. The anterior and posterior teeth of this species differ exceedingly in shape; the former are fiattened, sharp-edged, and slightly incurved ; the CROCODILIA. 165 edges not serrate. Those of tlie premaxillary bone are subequal in size, while one behind the middle of the maxillary is larger than the rest. The posterior teeth have short, very obtuse crowns with elliptic fore-and-aft outline. They resemble some forms seen in Pycnodont fishes, and are closely striate to a line on the apex. The upper surface of the cranium is pitted, the frontal and parietal bones with large, deep, and closely-placed concavities. The former is perfectly plane and the latter is wide. The squamosal arch is also wide, and the crotaphite foramina are large and open. The dermal scuLa are very large for the size of the animal, and were not united by suture. They are keelless and deeply pitted, with smooth margins. The vertebral centra found with other specimens are round. The coossified neural arches indicate the adult age of the animal. Measurements. Height of crosvn of premaxillary tooth 004 Width of crown of premaxill.ary tooth at hase 0035 Long diameter of crown of a maxillary 005 Short diameter of crown of a maxillary 0035 AVidth of pariet.al 009 Width of frontal, posterior 020 Width of frontal, interior orbital 010 Width of m.alar below the eye 008 The variation in the form of the teeth is a slight exaggeration of that seen in the dentition of various species of crocodilians. The axial portion of the basioccipital bone is a transverse vertical plate with vertical carina on the distal half. The frontal bone exhibits no ledge or crests, and the crotaphite foramina are open. The quadratojugal arch is stout. The dermal scuta are not united, and with the cranium, are deeply pitted. They are very abundant in some of the beds of the Green River epoch. Some of them exhibit a faint trace of keel. Vertebrae asso- ciated with them have subround articular extremities. This is the smallest North American species, and is as small as any mem- ber of the genus that is known. It did not probably exceed three feet in length. I only found it in the beds of the Wasatch or perhaps Green River epoch, south of Black Butte, Wyoming. A species of similar proportions 166 THE WASATCH AND BRIDGER FAUNJE. left its remains in the Bridger beds, judging from vertobrnc wliicli I found on Black's Fork of Green River. A somewliat similar'sniall species is found in the Wasatch beds of New Mexico, the C. chamensis Cope. In that species the dermal scuta are articu- lated together by suture. MAMMALIA. The lacustrine Eocene strata have been found in all parts of the world, where existing, to contain remains of an abundant mammalian life. The character of this mammalian fauna has been found to be particularly inter- esting, and for the following reasons. Much light is thrown on the history of the Mammalia by the researches into the structure of those of the Eocene formation, and I deem it demon- strated to a certainty that the case with the mammals of this formation is the same as with the rej)tiles of the Permian, i. e , that the family types are all more generalized, and the orders not nearly so widely distinguished as in later periods of the world's history. The recent orders of fishes were in existence in the Cretaceous period, and probably earlier. Their period of evolution was in the Devonian and the Carboniferous periods. The existing orders of reptiles were all estab- lished prior to the Eocene; the period of evolution was the three Mesozoic ages, but especially the Permian. The orders of birds were inchoate in the Cretaceous, but when they were fully differentiated is unknown. The existing orders of Mammalia were already established in the Miocene period; during the Eocene they were in process of differentiation, and were less, or scarcely at all distinctly defined.* Tiie characters of the Placental Mammalian orders which existed during Eocene time are as follows: 1. Ungual phalaiiffcs cla\v.s (uuguiculate). a Cerebral heniispberes small ; cerebellum aud olfactory lobes large anil iincovcrfd. fi Teeth slu-atht'd in t-namt'l. Glenoid cavity longitudinal ; mandibular condj'le round ; anterior limbs ambulatory Rodentia. •Sci' Aiimml Report U. S. Gcol. Surv. Terra. 1872, \k G4,'>. MAESUPIALIA. 1 67 Glenoid cavity and mandibular condyle transverse ; anterior limbs constructed for flight Chiroptera. Glenoid cavity and mandibular condyle transverse; anterior limbs ambulatory Bunotheria. II. Ungual phalanges hoofs (ungulata). a Os magnum supporting the lunar and not articulating with the scaphoid. The astragalus articulating with the navicular only, and the cuboid with the calcaneum only Taxeopoda. (The astragalus articulating with the navicular only; cuboid articulating with distal faces of calcaneum and navicular. Prohoscidia.*) The astragalus articulating with the cuboid and navicular.. Amhlypoda. aa Os magnum supporting the scaphoid, and more or less of the lunar. Astragalus articulating with both cuboid and navicular Biplaethra. MARSUPIALIA. Although many of the Mammalia of the Lower Eocene formation re- semble the Marsupialia, few of them present chai'acters which are unques- tionably those of that order. They appear in many instances to possess characters of the Insectivorous and Carnivorous orders as well, so that it has been thought best to refer them to a single order in combination with the Insedivora, the Bunotheria. A few species, however, present the mar- supial facies so decidedly, as to leaye no alternative but to refer them to that order, until further evidence shall confirm or set aside such a conclusion. The two genera now to be treated of are not very nearly related to any existing form of Marsupials. The nearest ally of one of them at least is characteristic of the Jurassic age, and has been referred by Professor Marsh to a distinct order under the name of the Allotheria. As Professor Mai'sh does not offer any characters by which this group can be distin- guished as an order from either the Marsupialia or the Bunotheria, I have not been able to adopt it. As Falconer has suggested, their nearest ally is perhaps Hypsiprymnus among the existing Marsupials, and Thylacoleo has perhaps an equal affinity. As the only part of the structure of these genera which is well known is the dentition, I define them as follows. The family of the Plagiaulacidce differs from that of the MacropocUdce in the possession of but two inferior true molars. Most of the genera have the fourth pre- * Not known a8 Eocene. 1(38 THE WASATCH AND BRIDGER FAUN^. molar trenchant, and generally those anterior to it also, while in the Macro- pidce the trenchant premolar, if present, is the third. The genera diflFer as follows: a Several large cutting premolars. Premolars four, sides not riil;;ed Ctenacodon. I'reutohirs typically tliree, with oblique lateral ridges Plagiaulujc. a a One large cutting premolar. P Inferior molars large, with several tubercles. Large premolar without posterior cusp; edge directed upwards; sides ridged Ptilodm. a a a Fourth premolar rudimental or wanting. Large premolar with posterior cnsj); edge directed forwards; molars with two rows of tubercles Catopmlis. Fourth premolar? wanting; molars with three rows of tubercles Pohjmaxtodon. ,? ,? Inferior molars small, with few lobes; the last rudimental. Large premolar without posterior cusp; edge directed upwards; sides not ridged Thylavuko. Of the above genera, I'lagiaulax is represented by two species in the English Jurassic; Ctenacodon by two species in the North American Jurassic; Ftilodus by two species, from the Lower Eocene, one from France and one from North America ; Thylacoleo by one species from the Pliocene of Austra- lia; Catopsalis by two species from the Lower Eocene of North America; and Polymastodon by one species from the Lower Eocene of North America. The phylogeny of these forms in connection with that of the kanga- roos may be expressed as follows: It is evident that such forms as Thylacoleo^ Ptilodus, and Catopsalis are more specialized than Playimdax ami Ctenacodon, inasmuch as the number of teeth is reduced, and the cutting function of the premolars is concentrated in a single large tooth, or is obsolete. This is quite the same kind of specialization as that which has taken place in the history of the descent of the Carnivora. Ctenacodon, as having the largest number of premolars, which have the least amount of sculpture, is the least specialized of all the genera. Thylacoleo, with the rudimental character of tiie true molar teeth, is the most specialized, as it is the latest in time. The Alacropodida: retain the full series of true molar teeth of the ])riniitive jMammalia, and pre- sent only a cutting third premolar in the lower jaw, the fourth reseu)- bling the true molars. Thus the cutting tooth of Thylacoleo is not the homologue of the cutting tooth of Uypsiprymniis as suj)posed by Professor Flower;* since tlu- latter corresponds with the cutting tooth of Ptilodus, ' Quarterly Jonnml Gcologiciil Society, 1868, p. 307, vol.'zxiv. MAESUPIALIA. 169 which is the fourth premolar of Plagiaulax. We must therefore regard Hypsiprymnus as the descendant of a type from which the Plagiaulacidce were also derived, in which some of the premolars, as far as the third only, were trenchant, and in which the fourth premolar possessed the tubercular character of the three true molars. Such a type would belong to Jurassic and perhaps even to Triassic times, and might well have continued to the Eocene. I call it provisionally by the name Tritomodon. The lines of de- scent will appear as follows: Tritouiodoa (theoretical). / ^ Ctenacodou. / Plagiaulax. / ^ / Ptilodus. / Catopsalis. / Hypsipryinnus. / \ Thylacoleo. Macropus. The discussion between Professor Owen on the one hand, and Messrs. T'alconer, Kreflft, and Flower on the other, as to the nature of the food of Thylacoleo, is known to paleontologists. From the form of the teeth alone Professor Owen inferred the carnivorous natui'e of the food of this genus, while his opponents inferred an herbivorous diet from the resemblance between the dentition and that of the herbivorous Hypsiprymnus. As the result of the discussion affects in some degree the genera Catopsalis and Ptilodus, I recall it here. The comparison of Thylacoleo with Hypsiprymmis is weakened by two considerations: first, the fact that the cutting tooth of the former is not homologous with the cutting tooth of the latter; and sec- ond, that the grinding series of the former is rudimental, and in the latter it is complete. It evidently does not follow that because Hypsiprymnus is 170 Tin: WASATCH AND BRIDGER FAUX.E. lierbivorous, Thijlacolco is so also. Professor Flower refers to the absence of molars in ThylacoJeo as slifrhtly complicating the problem, and concludes that the food of that animal may have been fruit or juicy roots, or even meat. It is difficult to imagine what kind of vegetable food could have been apjiropriated by such a dentition as that of PtUodus and Thylacoleo. The sharp thin serrate or smooth edges are adapted for making cuts, and for dividing food into pieces. That these pieces were probably swallowed whole, is indicated by the small size and weak structure of the molar teeth, which are not adapted for crushing or grinding. It is not necessaiy to sup- |)0se that the dentition was used on the same kind of food in the large and the small species. In PtUodus medioEVUs the diet may have consisted of small eggs which were picked up by the incisors and cut by the fourth pre- molar. In Thylacoleo it might have been larger eggs, as those of crocodiles, or carrion, or even the weaker living animals. The objection to the suppo- sition that the food consisted of vegetables, is found in the necessity of swallowing the pieces without mastication. In case it could have been of a vegetable character, the peculiar teeth would cut off pieces of fruits and other soft parts as suggested by Professor Flower, but that these genera could have been herbivorous in the manner of the existing Macropodidcc, with their full series of molars in both jaws, is clearly inadmissible. CATOPSALIS Cope. American Naturalist, May, IStCJ (April 24), page 416. This genus is known from a part of a mandibular ramus with a few other bones associated. The jaw is broken off in front of the fourth pre- molar, and the fracture displays the shaft of a large incisor tooth. It is im- possible to state how many premolars there are. The fourth is of large size, and is exceedingly compressed. The alveolar border descends abruptly from its posterior root, having the outline of the diastema of the jaw in various rodents, where, however, it is edentulous. The result of this form is, that the crown is presented forwards in an acute edge. The inferior two- thirds of this edge is broken off, so lliat it is not possible to state whether it is grooved or serrate. The superior part is neither, mul rises into a cusp posteriorly. The two molar teeth are very peculiar, aiwl tlie first is much MARSUPIALIA. 171 larger than the second. The arrangement of the cusps is alternating on opposite sides of a median groove. The grooves are deep, and resemble the impression of a simply pinnate leaf with alternating leaflets. The coronoid process rises opposite the second molar. The inferior face of the posterior part of the ramus is flat, owing to both internal and external inflections. Both ai-e well marked, the latter bounding the masse- teric fossa, which is open in front, and without foramen. The internal in- flection bounds a deep fossa, like that seen in Hypsiprymnus and Macropus to terminate in the dental foramen. The only species of this genus known to me is from the Puerco horizon. Catopsalis foliatus Cope. American Naturalist, 1882, p. 416, April 24. Plate XXXIII c; fig. 2. The mandibular ramus which represents this animal is robust and deep. The alveolar line rises from behind forwards, as in Elephantidce and various rodents, and then suddenly descends. The inner side of the ramus is con- cave, while the external side, anterior to the masseteric fossa, is convex. The incisive alveolus is thus thrown inside the line of the molars in front. There is a large fossa exposed by weathering below and behind the last molar, which is identical with that seen in Hypsiprymnus and Macropus, and indicates a large dental foramen. Below the middle of the fourth premolar footh the incisor tooth is quite large, suggesting whether it had not a persistent growth, as in the Rodentia. The posterior cusp of the fourth premolar is triangular in profile, the ante- rior edge descending steeply. It is uncertain whether the edge of the crown rises again, forming another lobe. The apex of the cusp is conic. The first true molar is of large size and remarkable form. The crown viewed from above is a long oval. It has a deep median longitudinal groove, which sends out branch grooves alternately and at right angles to the edge. The spaces between the grooves form block-shaped tubercles, four on the inner and five on the outer sides, whose transverse diameter generally exceeds their anteroposterior. The median groove is open at its anterior extremity. 172 THE WASATCn AND DUIDGER FAUN^. The posterior is closed by an elevated convex margin. Tiie apices of the lobes are obtuse where not distinctly worn. The last (second) true molar is much shorter and a little wider than the first, and has the same character of surface. There are two large tubercles on the inner side and four small ones on the external side. The posterior end of the crown is narrower than the anterior. The anterior base of the coronoid i)rocess is opposite the posterior e.xtremity of the first true molar tooth. The jaw, with its denti- tion, in its present condition, has a curious resemblance to that of a tuber- cular-toothed Mastodon, witli the order of size of the molars reversed. Measurements. u. Length of base of true inol.irs 0166 Length of base of fourth premolar OlO(j Vertical diameter of root of incisor 0070 Diameters M. i J ""'•^■""P"*'^'"'"'" ^^^' ( transverse OO.'.O Diameters M. ii ^i-'t'T'.posterior 0060 ( transverse OOIM Depth of ramns at front of P-ni. iv 0120 Depth of ramus at front of M. i 0190 Depth of ramns at posterior eilge of .M. ii Ol.'O Width of ramus below P-m. iv 0070 "Width of inferior face of ramns below M. ii 0110 Found by my assistant, D. Baldwin, in the Puerco Formation of North- western New Mexico. PTILODUS Cope. American Naturalist, ISBl, November, p. 921 (October 28). Dental formula of infeT-ior series; I. 1 ; C 0; Pin. 'J; M. 2. Incisor occupying- a deep alveolus and probably growing from a persistent pulp. It forms an arc of a circle, with an anterior enamel band. First (third) premolar rudimental. Second (fourth) premolar disproportionately large, with compressed crown with a convex cutting edge, and lateral ridges di- rected upwards and posteriorly. Molars small; the first longer tiian wide, its crown divided by a deep longitudinal median groove into two lateral ridges, which are divided into lobes by transverse fissures. Tlio masseteric fossa is well marked. The intcnial pterygoid fossa is very deep and termi- nates in the foramen dentale, and is bounded below by a horizontal iuHection of the inferior border of the mandiltiil.ii- minus. MARSUPIALIA. 113 The characters of the fossre of the mandibular ramus are those of the marsupial order, and much like those of the family of the kangaroos. The absence of connection between the masseteric and pterygoid fossfe at the dental foramen distinguishes Ptilodus from that famil}^ The differences in the dentition have been already discussed. The announcement of the discovery of this genus in the Eocene forma- tion was a circumstance of much interest, and it has shown how persistent the type of the Plagiaidacidce has been. It is true that no representative of the Plagiaulacidce has yet been obtained from the beds of the Cretaceous period, which represent the long interval of time which elapsed between the Jvxrassic and the Eocene. We will not, however, on this account permit the supposition that they did not exist at that time. The existence of the Plagiaidacidce in the Eocene period v/as first ascer- tained by Dr. Victor Lemoine, of Reims, France, and was announced to the Geological Society of France at its meeting of January lO, 1881, and pub- lished in its Bulletin for 1881, p. 1G8, for May. This announcement had escaped my observation when six months later (October) I published the account of its discovery in New Mexico. I, at that time, gave the genus the name of Ptilodus, and I am not aware that Dr. Lemoine has yet printed any name, either generic or specific, for the form discovered by him. Ptilodus medt^vus Cope. Aniericau Naturalist, ISKl, p. 9'21, November; (published October 28). Plate XXIII c; fig. 1 This species is represented by two mandibular rami of probably the same animal, one of which lacks the part anterior to the premolars, and the other the part posterior to the premolars; by a single fourth premolar tooth of a second individual; and by all the inferior molars of a fourth. The ramus is short, and is deep posteriorly ; anteriorly its depth is re- duced by the concavity of the surface at the diastema, as in most rodents. The inferior border is i-ather thick anterior to its posterior expansion. The symphysis is not coossified. The incisor tooth is quite slender, and its sec- tion is a vertical oval, a little flattened on the inner side. The enamel band covers less than two-fifths of the face of the tooth, beginning with the inner 174 THE WASATCH AND BRIDGER FAUX.^. edge of the anterior face and extending externally. Its surface is entirely smooth. The diastema is moderately long. The first premolar is a very small tooth and has a single root. The crown is conic, and is pressed against a narrow truncate face of the base of the anterior edge of the fourth (second) premolar. Tiie vertical section of the fourth premolar is wedge-shaped, and the profile of the crown is regularly and strongly convex. The anterior root has a greater anteroposterior diameter than the posterior root, and the enamel extends further downwards on it than on the posterior root, on the external side; on the internal side this expansion is not so marked Tlie enamel of the sides of the crown is thrown into parallel ridges, which are gently curved, and which extend upwards and posteriorly to the edge, ex- cept at the posterior border, where they fall a little short of the edge. When they reach the edge the latter is angulate, forming a serrate outline. There are twelve ridges from front to rear, and the anterior ones are closer together than the posterior, the widths of the interspaces increasing in regular pro- gression. The first true molar is very small, absolutely and relatively, its length being one-third of that of the two premolars together. The outline of the crown is elongate oval longitudinally placed. The median groove is wide, and is open at both extremities. The lateral lobes have continuous longitudinal acute edges, and number four on each side. The posterior lobe is twice as long as any of the others on botli sides, and its edge is weakly notched. No cingula. The alveolus of the anterior root of the second molar indicates a rather wider tooth than the first molar. The anterior border of the masseteric fossa is a strong ridge, and passes the alveolar border at the posterior edge of the first true molar. The fundus of the internal pterygoid fossa is deeper or more external than the line of the molars, falling below the external edge of the anterior masseteric ridge. Measurements. M. Length of ramns to last true molar inclusive (hJ05 Diaiui-ters M. i 5 ""t'^roposterior 0040 ( f rnnsviirHC 0020 1 aiitLTopostcrior 0085 Diaiiietfr8 P-m. iv ? IraiisviTsc at l)ase 0030 ( vertical at middle 0045 EODENTIA. 175 M. Length of diastema 0060 T^ .„ . . . < anteroposterior 002(! Diameters incisor < '■ < transverse 0020 Depth of ramus at diastema 0070 Depth of ramus at middle of P-m. iv 0000 The length of the skull of this animal was about equal to that of the Norway rat Mus decimianus, but the large proportions of the fourth premolar indicate that the cranium was much deeper than in that animal, and had probably the form of that of the Thylacoleo carnifex* RODENTIA. Remains of species of this order are not abundant in the beds of the Wasatch epoch, and are rather common in those of the Wind River and Bridger. They are not very i^arious as to type, and the greater number are apparently allied to the squirrels. PLESIARCTOMYS Bravard. Plesiaretomys Bravard, Ossemens fossiles de Desbruge, 18r)0, p. 5. — Gervais, Pal^ontologie franjaise exijlic, tab. 30, p. 4. Paramys Leidy, Report U. S. Geol. Surv., 4to, i, 1873, p. 109; Proc. Pbila. Acad., 1870 (name only). Pseudoiomus Cope, Paleontological Bulletin No. 2, p. 2, August 3, 1872, nomen nudum; Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 610 (defined). The inferior molars by which this genus has been generally known resemble much those of existing Sciuridce, but there are cranial characters which distinguish it from the existing forms of that family. The crowns of the inferior molars support four rather small and strictly marginal tubercles, which inclose a median valley. The anterior inner tubercle is more elevated than the others, and the posterior -two tubercles are connected by a low ridge on the posterior border, which may be more or less tubercular on the last molar. In some of the species, the marginal tubercles are merely elevations of the margin, while, in others, the adjacent tubercles of a pair approximate, so as to form a pair of interrupted cross crests. There are five superior molars, of which the anterior is of small size. They resemble tliose of Sciurus, but the transverse crests are obsolete or *A restoration of the skull of this animal is given by Flower, Quarterly Jonrn. Geolog. Society, vol. xxiv, 1868. 176 THE WASATCn AND BEIDGER FAUN^. wanting:. The positions coiresponding to their extern.al extremities are marked by more or less distinct cusps. There is a single internal tubercle of the crown. In the third and fourth molars of P. deUcatissimns I observe rudiments of a second internal tubercle. The incisor teeth are compressed, with naiTOw anterior face. The enamel is not grooved, and is little or not at all inflected on the inner side of the shaft, while it is extensively so on the external face. There is a large, round foramen infraorhitale exterins, like that of Ischyromys and Fiber, and entirely unlike that of Gymnoptychus and Sciurus, conforming in this respect to the forms of the extinct group of the Protoniyides of Pomel. The cranium of the specimen originally described by me as Pseudoto- mus hians, exhibits the following characters: The superciliary margin is short, and without jiost-frontal process. The temporal fossa? are large, and contract the brain case behind the orbits to a striking degree. Their ante- rior margins rise from the post-frontal angles and converge backwards, meeting in a sagittal ridge opposite the anterior part of the squamosal bone. The parietal bones increase rapidly in width to the squamosal, which are largely inferior at their zygomatic portion. They do not extend very far on the superior aspect of the skull, nor backwards beyond the auditory meatus. The occipital region is concave, and sun-ounded by a prominent crest The foramen infraorbilate exterius has an inferior position, being a little above the alveolar border. Tliere is a prominent tuberosity on the under side of the basal front of the malar bone, just exterior to the position of the second molar of Ardomys ; its inferior face is truncate. The pterygoid laminaj are jjrolonged, inclosing a trough. Their sphenoid ala? descend steeply from their posterior base, and have an external ridge, which marks out a pterygoid fossa. The otic bulla is not large. Paroccipital process distinct. T\\q foramen ovale is large, and is divided by a thin bridge of bone. The two external foramina resulting are also the alisphenoids. There are no additional foramina in this region. The space for the otic bulla is moderately large; the basicranial axis is grooved at the junction of the basioccipital and sphenoid bones. The zygomatic arch is deep and thin. The glenoid cavity is wide but longitudinal. The cast of the brain indicates smooth oval hemispheres, which leave RODENTIA. 177 the cerebellum and olfactory lobes entirely exposed. The latter are ovoid and expanded laterally. The coranoid process of the mandible is large and high, as in Arctomys. The condyle is small and compressed. The angle is produced, so that the posterior border of the ramus is concave. Associated with the skull of a P. delicatissimus are various parts of the skeleton. A lumbar vertebra is not elongate ; its anterior articular face is slightly convex and the posterior plane. The outline of the former is a little more than half a circle. The diapophyses are large, and are opposite the floor of the neural canal. The prezygapophyses are subvertical, and the superior exterior edges are developed into well marked metapophyses. The middle line below has a low narrow keel, which separates two large nutritious foramina. The proximal part of the scapula is preserved. It resembles in gen- eral that of a squirrel, having a recurved coracoid process, and a well developed acromion. The latter is quite flat, and is continuous with a hori- zontal expansion of the spine. The humerus has a subround head, and the tuberosities are little prominent, and enclose but a shallow bicipital gi-oove. The deltoid crest is prominent, and extends to the middle of the shaft. Its inferior portion is more prominent and compressed than the superior por- tion. The teres facet is well marked. The distal end is transversely extended by the large size of the internal epicondyle. The condyles are simple hour-glass-shaped, and without crest. The epitrochlear foramen is distinct. The ulna and radius are long and slender, and their carpal arti- cular surfaces are of subequal size. The head of the radius is nearly round. Two metacarpals are preserved, and they are rather short ; there is an inferior trochlear keel of the distal articular extremity. The pelvis is much like that of a squirrel. The ilium is not much expanded towards the crest, but cannot be called prismatic. Its external rib is near the anterior border, and the posterior edge is thin, and bounds a concavity of the external face. The anterior inferior spine is prominent The ischium is two-thirds the length of the ilium, and is moderately expanded distally in a vertical plane. Its spine is distinct Fragments of femora, associated with the other specimens, have the characters of those 178 THE WASATCH AND REIDGEU FAUN^. of the SciuridcE. The great trochanter is about as high as the head, and bounds a large fossa. The little trochanter is well developed. The rotular groove is moderately elongate, with nearly equal bounding keels. The condyles are subequal and present posteriorly. The distal extremity of the tibia supports an internal malleolus which is flat on its inner side, and is without distal facets. The external trochlear groove of the peronealy is larger than the internal. The posterior border is produced downwards in a subangular process as in other iSciurida; which is as long as the malleolus, and is openly grooved to carry the tendon of the flexor longus polUcis mus- cle. It is separated by a deep notch from the internal malleolus, through which passed the tendons of the flexor longus digitorum, and the tibialis pos- ticus muscles. The astragalus also resembles that of a squirrel. The head is du-ected inwards from the anteroposterior axis of the troachlea, and has a depressed and convex distal extremity. The trochlea is wide, and the groove is well marked. Its external and internal faces are vertical. The calcaneum is large, and the free portion is compressed. The sustentaculum is small. The species from which most of the characters of the genus as above stated have been derived are the P. delicatior and P. delicatissimus. They display the following general points. The. anterior limbs are relatively longer than in recent species of squirrels. The bead of the radius is rounder, indicating an unusual power of rotation of the anterior limb. The pelvis is larger, being as long as the skull, and it is probable that the posterior limb is larger. These points indicate approximation to the Mesodotda. No characters have yet been oflfered by which to distinguish the Ameri- can species as representing a genus distinct from the Plesiarctomys gervaisii of the French Eocene. Bravard briefly distinguishes the genus as distinct from Ardomys in the greater thickness of the angles of the molars, which thus become tubercles. Only the mandible and mandibular teeth of the P. gervaisii are known. It has been idund in thf Tppi r Eocene, near Perreal, Apt, France. I have seen five species of this genus, of which one, P. liiaua belongs to the Bridger beds ; one, P. leptodus, to the Washakie ; one, P. buccafus, to KODENTIA. 179 the Wasatch and Wind River, and two, P. delicatior and P. delicatissimus, to all the Eocenes except the Washakie. Plesiarctomys bucuatus Cope. Report U. S. Geol. & Geog. Expl. Surv. W. 100th Meridian, G. M. Wheeler, iv, pt. ii, p. 171 ; pi. xliv , fig. 8. Plate xxiva, fig. 14. Jaws of four specimens which agree in proportions with those of this species found in New Mexico, were obtained by Mr. Wortman in the bad lands of the Big Horn basin, Wyoming. The species was established on a maxillary bone bearing teeth, while the present specimens are all mandibles. I do not detect any difference between these and the lower jaws of P. delicatissimus, excepting the inferior size of the former, from which, however, the first and last molars are wanting. I give the following measurements : Measurements. M. Length of inferior molar series 1 ~ 012 Length of base of last molar 0038 Diameter of inferior incisor 5 '^"tero-posterior 0033 transverse 0008 Depth of ramus at second molar 0088 Plesiarctomys delicatissimus Leidy. Cope, Report U. S. Geog. & Geol. Expl. Snrv. W. of 100th Mer., G. M. Wheeler, iv, pt. ii, p. 172, pi. xliv, figs. 9-12. Paramys deUcatissimus Leidy, Proceed. Acad. Phila. 1871, 231 ; Report U. S. Geol. Sui-v. Terrs, ii, p. Ill, pi. vi, figs. 28-9. Plate xxiva, figs. 1-10. Poi'tions of the mandibles of four specimens of this rodent were brought by Mr. Wortman from the Wind River Basin ; also, the skull of another individual, and the greater part of the skeleton with the skull of a sixth individual. The specimen last mentioned furnishes the following characters. The skull has much the form of the large arboreal squirrels of the present day. The muzzle is of moderate length, and the zygomata are not very widely expanded. The skull is contracted just behind the eyes, for the orbits are not defined posteriorly. Above the eyes the superciliary border is angu- lar, but not prominent, and each one is continued as a delicate anterior tem- poral ridge. The ridges converge backwards and unite into a low sagittal crest opposite the anterior angle of the squamosal bone. The anterior supe- 180 THE WASATCH AND BRIDGER FAUN^. rior angle of the malar bone forms the inferior half of the anterior border of the orbit, but its inferior part is supported by a peduncle of the maxillary bone. Its posterior angle extends as far posteriorly as the external border of the glenoid cavitv. The occiput is vertical, and is wider than deep. It is convex in the position of the vermis, and concave on each side above the occipital condyle. The condyles are rather small, and are widely sepa- rated, bounding a very large foramen magnum. Inferiorly the basiocci- pital is flat in front of the condyles. Between the otic bullae it has a median keel, with a concavity on each side, bounded externally by a prominent desceiuling border in contact with the bulla. The massateric fossa of the mandible reaches the line of the posterior border of the penultimate molar tooth. The articular service of the condyle is nearly round, and is strongly convex, and projects as far backwards as a vertical line drawn from the angle. The coronoid process is much higher, and has a wide summit with a convex border. (^f the superior molars, the apex of the minute first is bifid, one cusp being the larger ; the second is a little narrower than the third, and the fifth is a little wider antero-posteriorly. The enamel is smooth on all the teeth in both jaws, including the incisors, and there are no cingula. "^riie extremities of the coracoid and acromion are about in one hori- zontal line. The former is abruptly turned backwards and truncate on the external face. The ulna and radius appear to have lost their epiphyses ; allowing for this, they are a little longeithan the humerus. The shaft of the ulna is rather compressed, while that of the radius in round in section. The distal expansion of oach is about equal. The trnclianteric fossa of the femur is very deep, and the little trochanter is very large. The third trochanter is represented by a low ridge. The distal extremity of the tibia has nearly equal anterojjosterior and transverse diameters, and the shaft at the distal two- fifths the length is nearly round. Mcasuremenis of No. 6. M Length of skull to lateral border of external nares to parocoipital process (ITOO Length from lateral edge of nares to orbit 02Q0 Lengt li from anterior border of orbit to posterior edge of zygomatic fossa OIKH) Length from posterior border of superior incisor to tlrst molar 0170 KODENTIA. 181 M. Le.igth of superior'molar series 0145 Length of molars II ami III together 0065 Length of molars IV and V together 0070 Transverse diameter of M. II 0042 Transverse diameter of M. V 0035 Width at eyes 0165 AVidth behind eyes 0100 Length of mandibular ramus from incisor to condyle 0400 Length of diastema 0060 Length of molar series 0135 Dejith of ramus at second molar 0100 Depth of ramus at coronoid process 0310 Depth of ramus at condyle 0235 Length of humerus (Nos. 5 or 6) 0600 _ . , ,. ^ „, ( anteroposterior of head 008 Proximal diameter oi humerus/ ..,,,,.. „, , ( transverse, with tuberosities Oia Distal, with humerus 016 Width of distal condyles of humerus Oil „. ^, , „ ,. (vertical 006 Diameter of head of radius < . „„, I transverse 007 Depth of radius (f minus epiphysis) 048 Depth of ulna at coronoid 006 Anteroposterior diameter of head of femur 009 Transverse diameter at little trochanter ■ 0135 Transverse diameter below little trochanter 009 Transverse diameter at distal end 016 Vertical diameter at distal end (greatest) 015 Diameter shaft of tibia at distal two-fifths of length 006 „ ,. , , ^ ., . (anteroposterior 010 Diameter at distal end ol tibia < , „,„ ( transverse 010 „. „ ,, „ . , (anteroposterior 008 Diameter of trochlea of astragalus ; , „„_ ° ( transverse 007 Length of head of astragalus 005 Angle of axis of head with trochlea 9° „. ^ „ • 1 r (vortical 0045 Diameters oi navicular race < ^ „„^„ ( transverse 0066 Length of a metatarsal 029 Length of ilium to acetabulum 0785 at crest 0150 I at acetabulum 0105 Vertical diameter of acetabulum 0105 Length of ischium 0128 ,„.,,, .. ,. ( at acetabulum 0075 Widths of ischium < ,,.,,. , „,^n I at distal border 0150 From the above measurements the following comparisons with the Sciu- rus niger may be made : The pelvis is longer as compared with the bones of the fore leg. The humerus is longer as compared with the length of the ulna and radius. The species exceeds the 8. niger in size, one-fourth linear. 182 THE WASATCn A^TD BRIDGER FAUN^. Plesiabctomys delicatior Leidy. Cop«, Report U. S. Geog. & Gool. Expl. Surv. W. of 100th M.r. G. M. Wheeler, iv, pt. ii, p. 172. Para- myi deUcati<»r Leidy, Proceed. Acad. Phila. 1B71, p. 231. Report U. S. Geol. Surv. Terrs. ISTJ, i, p. 110, pi. vi, Ugs. '2(>-7, pi. xxvii, tigs. 16-18. Plate xxiva, tigs. 11-13. This squirrel is represented by the jaws of at least four individuals in Mr. Wortman's Wind River collections. Two of these are further repre- sented by other portions of the skeleton, one of theiu including a maxillary bone with four molars in place. The bones of the skeleton coincide with the teeth in their superior dimensions as compared with those of the P. delicatissimm. The pieces of the last-named individual which are preserved are portions of the femur and tibia, with astrogali and calcanea ; also, portions of ulna and metatar- sals and ribs. The only difference of form I observe between these and corresponding parts of P. delicatissimus is in the distal extremity of the tibia ; This has a relatively greater transverse diameter as compai-ed with the anteroposterior than in the species just named. The calcaneum of the right side is nearly perfect. The free portion is strongly compressed ; the anterior portion appears depressed on account of the extent of the sustenta- culum on the inner side, and the well-developed corresponding process on the external side opposite to it. The cuboid facet is, however, as deep as wide, and truncates the calcaneum transversely. The external astragaline facet is very convex, and presents inwards and a little forwards. The superior molars accompanying, this specimen are of the size and proportions of the inferior molars, but they belong to the Mesodont, Pehj- codus frugivorus, described later in the present work, where the distinction between the molar teeth of this genus and those of Pelycodus are pointed out. Measurements. M. Length of inferior molar series 016 Length of last inferior molar 005 Longlh of diastema 0085 Depth of ramus at ponultimute molar 0115 Diameter of shaft of tibia two-fifths distance from extremity 0073 „. ^ /■ • • r .t ■ (anteroposterior 0095 Diameters of extremity of tibia? \ f riinsverse 01 10 antemposterior 009O Diameters of trochlea of astragalus \ traasverbo OOSO EODENTIA. 183 M. Length of head of astragalus 0055 Diameters of navicular face of astragalus )^ nnon ( transverse OUoO Depth of heel of calcancum at base 0080 Depth of cuboid facet of calcancum at base 0057 Width at susterotaculum 0132 Plesiaectomys leptodus Cope. Faraniys leptodus Cope, Paleontological' Bulletin, No. 12, \i. 3, March 8, 1873. Plate xxiv, fig. 1. Established on a right mandibular ramus with all the teeth preserved. It indicates an animal of about the size of the P. delicatus Leidy, but with smaller incisors, which have little more than half the diameter of the same tooth in those species. The molars have two anterior separate, and three posterior contiguous cones, the median smallest, the anterior and posterior of both sides separated by a deep excavation. The anterior tooth is pecu- liar in its greater compression. The posterior tubercles are not separated, and the anterior inner is situate behind the outer, and is connected with the posterior inner by a concave ridge. Measurements. If. Length molar series 0221 Length M. IV 0060 Width M. IV 0055 Length M. I , 0060 Width M. I 0048 Diameter lower incisor, transverse 0024 Diameter lower incisor, anteroposterior 0038 From the South Bitter Creek, Wyoming, from the Washakie Basin. Plesiaectomys hians Cope. Pseudotomus hians Cope, Paleontological Bulletin No. 2, p. 2, 1672. Annual Report U. S. Geol. Sury. Terrs., 1872, p. 611. Plate xxiv, figs. 3-5. This species was established on a nearly complete cranium, from which some parts of the walls are broken, and only the anterior portion of the mandible remains. It belonged to an old individual which had lost its molar teeth, and whose inferior incisors are very much worn. The cranium is of depressed form, and with considerably expanded 184 THE WASATCIJ AND liKID(iEK FAUX^. zygomata. The muzzle is broad and but little elevated, so that the nasal meatus is between the alveolae of the superior incisors. The enamel of the superior incisors is not grooved, but has a delicate striate sculpture. The inferior incisor does not project as far as the alveolar border of the jaw, its surface worn by the upper incisor is horizontal and anterior. The inferior diastema is a thin edge, and the ramus is deep there. The temporal surface of the parietal bones is rugose. The cranium is depressed, and has a trace of sagittal crest. The anterior margin of the temporal fossa is marked by a curved angle on each side of the frontal bone. The supra- orbital arch is very short. The mandibular incisors ai'e narrowly separa- ted by a naiTOW prolongation of the symphysis. The exposure of the tooth is lateral, its direction nearly anterior. It projects anteriorly very little beyond the symphysis, and has a horizontal triturating surface below the level of the latter. There are alveolae for but three molar teeth, each with three roots. The teeth themselves are not contained in them, but were apparently lost before the cranium was entombed in tlie Eocene mud. The position of the first molar is occupied by spongy bone in both maxil- laries, and appears as though such teeth might have existed eai-lier in life, and been shed. Measurements. M. Longth of cranium (3.75 in.) 095 Width of cranium (without zygomas) 040 Width of cranium (with zygomas) 072 Width of occiput 032 Width of occiput near end of nasals . 027 Width of ui)pcr cutting tooth 007 Depth of upper cutting tooth 0085 Length exposed i)art lower tooth 009 Width exposeil i)art lower tooth 006 The species differs from the P. delicatus Leid}', in its superior size, being, in fact, the largest species of the genus. The typical specimen was found by myself on Cottonwood Creek, Wy- oming, in the IJridger beds. BUNOTHERIA. 185 BUNOTHERIA. This division embraces the imguiculate Mammalia of low cerebral development, which have the transverse articulation of the lower jaw, and ambulatory limbs. It embraces a series of types which present a great range of variation in dental characters, but which at the same time pass into each other by sensible gradations. I^js jpossible that some of the types whichXtave referred here may turnj)ut to be Marswpialia^ hut jhe^ number of such cases is probably spiall. . The following is the definition of jhisj)rderi- Cerebral hemispheres small, leaving the olfactory lobes and cerebelum exposed ; the surface smooth, or nearly so. Limbs ambulatory, armed with a greater or less number of compressed ungues. Articulation of the mandi- ble transverse. Molar teeth of the superior series (and usually ot the lower) tubercular, and without continuous crests. Incisor teeth present in the premaxillary bone. Teeth invested with enamel. Feet with five digits (with a few exceptions). Usually a third trochanter of the femur. I once applied to this order the name Insedivora, so as to avoid the creation of a new one, but I subsequently concluded to adopt the latter course as the preferable one. The name Insedivora has acquired currency as applied to the well-known modern group of that name, and its applica- tion to types of such apparent diversity as those now associated under a single head is not a convenience. I therefore proposed the name Bunotheria for the order, and included under it the suborders Creodonta, Mesodonta, Insedivora^ Tillodontu, and Taeniodonta* I suspect that the Prosimice must also be included in this order. The suborders are characterized as follows: Superior incisors normal, not growing from persistent pulps; canines much enlarged ; premolars compressed ; molars more or less sectorial ; astragalus generally not grooved above, articulating with cuboid and navicular; scaphoid and lunar bones (? always) distinct Creodonta. Incisors not growing from persistent pulps ; molars tubercular, never sec- torial ; third trochanter elevated ; astragalus not grooved above Mesodonta. Incisors enlarged, simple, not growing from persistent pulps, canines re- duced ; astragalus concave above Insectivora.i * Report of Lieut. G. M. Wheeler of the Expl. Surv. W. 100th Mer., iv, 1877, p. 72. tThe typical Intectivora, Linn., Bonap., Gill. 186 TnE WASATCH AND BRIDGER FAUN^. Incisors much eularged, growing from persistent pulps, and faced with enamel in front only ; therefore scalprifonn Tillodonta. Incisors much enlarged growing from persistent pulps, the superior with enamel in anterior and posterior bands, and hence truncate Taniodonta. The order of JBunotheria with tliese subdivisions, is not more heterogene- ous than that of the Marsupialia, and presents a great similarity in its com- ponent parts. Thus the Creodonta resemble Sarcophaga, the Insectivora the Entomophaga, and the Tillodonta the Bhizophaga. Fhascolamys, the type of the last suborder presents several points of resemblance to the Tillodonta. The affinities of the groups here combined under one ordinal caption are very divergent. The order is generalized, and, as such, does not present the peculiar features of the Chiroptera, Modentia, and Edentatu, but is so far negative in its character as to preclude more than subordi- nate subdivision. While the existing division Insectivora maintains the typical characters, the Dermoptera, also existing, are doubtless relics of the group from which the Chiroptera derive their ancestry. The Tillo- donta exhibit some kind of affinity to the Rodents, while the Tceniodonta present us with a point of connection with the Edentata. The discovery of this fact was particularly welcome, as we had not previously had any hint of the relations between that anomalous order and the remainder of the Mammalia. So far the relationships indicated are to smooth-brained (lissencephalous) orders only. The connections with the Gyrencephala (or Educabilia) are quite as close; namely, as already pointed out, through Me-so- donta to the Prosimice and the Quadrumana, and through the Creodonta to the Carnivora. Standing in this structural relation to different existing types, and in an antecedent relation as to time, it is easy to look on the Bunotheria as ancestral to some of them. In the first place, the Insectivora represent them in the existing fauna. The Creodonta are probably the ancestors of the Carnivora, and the Mesodonta of the Prosimiel face of the second incisor is thrown into shallow longitudinal grooves with more or less numerous irregularities, from the low dividing ridges. There is a deeper groove on each side of the tooth, and there are about a dozen ridges between these on the anterior face. Both cusps of the first premolar are conic, and the exter- nal is the larger. The second true molar is a little smaller than the first. The enamel of the premolars and molars is smooth, and there are no cingula. Probable length of dental series .0750; diameters of I. 1: anteropos- terior .0120, transverse .0066; diameters I. 2: anteroposterior .0160, trans- verse .0115; diameters Pm. 1.: anteroposterior .0072, transverse .0130; di- ameters of M. 11: anteroposterior .0090, transverse .0090. Length of true molars .003b; depth of ramus at M. 11. .0360. The short deep jaws of this animal must have given it a very peculiar appearance, not unlike that of a parrot in outline. PSITTACOTHERIUM ASPASKE CopC. PaleoDtological Bulletin No. 34, p. 192, Feb. 20, 1682; Proceed. Amer. Philos. Soc. 1881, p. li*2. Plato XXIV c, figs. 3-4. Represented by two mandibular rami of two individuals, one adult, the other nearly .so, but with the last inferior molar not fully ))rotruded. The latter specimen must be used for description, as it presents two molar teeth, while the other specimen has lost them. The most obvious difference from the P. mHltifrayum is its inferior size^ INSECTIVORA. 197 which can be readily perceived from the measurements given. The poste- rior crest of the molars appears to have less transverse extent than in the larger species. This crest in the last inferior molar has a curved crenate edge, with a small conic tubercle at its external extremitj-. The anterior crest consists of two conic tubercles, whose apices converge, but whose bases are closely appressed, and only distinguished by a superficial fissure. The valley between the crests is iminterrupted. The preceding molar is larger, and its posterior crest is like that of the lost molar. The apex of the anterior crest is broken off. The ramus deepens rapidly forwards, and contains the enormous alve- olus for the incisors. The coronoid process leaves the alveolar boi'der at the line separating the last two molars, or, in the smaller specimen, a little an- terior to this point, and is quite prominent. The masseteric fossa is well marked, but shallows gradually anteriorly and inferiorly. Measurements, No. 1. u. Depth of ramus at penultimate molar 027 Width of last molar anteriorly 008 Length of crown of do 009 No. 2. Depth of ramus of penultimate molar 029 Dei)th of ramus at P-m. ii 043 Length of five consecutive alveoli 047 From the Puerco bed of N. W. New Mexico. Discovered by my as- sistant, Mr. D. Baldwin. INSECTIVORA. To this suborder I refer the genus Esfhont/x, on account of the near resemblance of such parts of the dentition as are known, to some of the genera now existing. It is not unlikely that other genera of the Eocene which have been referred to the Insectivora belong here. Esthonyx exhibits an approximation to the Tillodonta in the restriction of the enamel-layers of the incisors of one of the jaws to the anterior face only. The inferior molars have much the constitution of those of Anchippodus, and in their details resemble also those of Erinaceus. As compared with the Creodonta, there is a near resemblance between these teeth and the tubercular molars 198 THE WASATCH A>T> BRIDGER FAUN^. of Didy'mictis, and throu 1 :■: < anferoposterior ' Oi*(i Diainetors crown F-'ni. in •; ' I transverse .007 T.. . T> • < anteroposterior 007 Dinmeters crown P-ni. iv •; ' ( transverse Oil Tx- » If • $ anteroposterior OOS Diaiueter.s crown M. i ^ ' i transverse Oil DiameterecrownM.iiiJ»"'*^^°P"«t'^"'"' ^ I transverse 008 Lcnjjih of mandible from incisive border to edge of angle 1-22 Length from incisive border to anterior basis of coronoid process 074 Length of base of coronoid ]iroccss 033 L(;ngth of syrai>hysis (oblique) 043 Depth at P-ni. iii , 0J3 Depth at M. iii 0->3 Depth at condyle 037 Width between inferior canines at base 007 Diameter of base of inferior canine (long) 010 Length of nndar series from canine 053 Length of premolar series OM Diameters crown P-m. ni ^ ""teroposterior (oblique) 0075 ( transverse (oliliipie) ■ — .iXHi Diameters crown P-m. j,- ^ '""•'■'"P"''*''""'- "/" ( transverse 007 DiametersM.i J »""""1""" '■""■• "" ( transverse The internal roots of the superior molars are jn-oduced inwards, giving the crowns a strong internal support and extension at the base. The enamel IXSECTIVORA. 201 is best developed on the internal side, while on the inferior molars it extends further on the external side. A portion of the frontal bone preserved shows that the interorbital reg-ion is flat, and that there is a strono: sasfittal crest. The chambers for the large olfactory lobes fall below the anterior part of the sagittal crest. The glenoid cavity of the squamosal bone is wide anteroposteriorly,and has no anterior crest. The postglenoid foi'amen is rather large. The anteor- bital foramen issues above the j^osteiior part of the third superior premolar. The proximal end of the humerus displays a well-developed, rather flat, greater tuberosity (with a distinct teres facet), which is continued as a prominent bicipital ci'est to the lower part of the shaft. The distal extremity exhibits an epitrochlear foramen. A part of the shaft of the ulna is vei'y robust; both sides are grooved. The shaft of the tibia is quite slender, with the long diameter anteroposterior, the posterior edge acute on the inferior tliird. The edge turns outwards, forming the posterior edge of the wide tibular face. Internal malleolus pi'ominent distally, most so posteriorl3^ The astragalar face is oblique and nearly flat, or slightly concave, having even less excavation than that of most creodonta. Measvrements of limbs. M. Least diameters of humerus ^■'"^'■"^I'°«t'^"»'• 009 < transverse ; 014 De|itli shaft of ulua at middle 012 Diameters shaft tibia ^'^"**'"l«'«t«'"'"- O'^g ( transverse 006 „. ^ » t ii ■ ^anteroposterior OH Diameters extremity tibia •' ' < transverse 015 Tliis species was robust in its characters, and evidently lived on hard food; its strong and worn canines show that they had more than the usual use. In its dentition it stands nearer the creodonta than does any other member of the group. It was probably a burro wer. CONOEYCTES CRASSICUSPIS Cope. Plate XXIII d; fig. 6. The posterior part of a mandibular ramus supporting the last two molar teeth indicates a second and larger species of the genus The ramus is one-half deeper than that of the C. comma, and the second true molar is 202 THE WASATrn and p.ridger fauna. much larger than in that species. Tlie last true molar is much smaller than the penultimate, and consists ot three anterior cusps and a longer heel. The former are obtuse, the external the larger, the internal equal, the ante- rior on the inner edge of the crown. The heel sustains a low conic tubercle. Measurements will be given in the explanation of the figure above cited. From the Puerco beds of northwestern New Me.xico. ESTHOXVX Cope. Report Vert. Foss. New Mexico, U. S. Geoj;. Survs. W. of 100th Meridi.nn, 1874, p. G: Id., Ami. Report U. S. Geog. Survs. W. of 100th Mcridi:iii, 1^74, p. 11;^; System. Cat. Vert. Eocene, New Mexico, U. S. Geog. Survs. W. of 100th Meridi.aii, 1875, p. 23; Report U. S. Geog. Survs. W. of 100th Meridian, vol. iv, pt. ii, 1877, p. l.")3. The dental formula is, I. ^; C. : P-m. ' ; M. -. 6 1 6 6 Incisors of two forms, the inferior subgliriform, but not growing from persistent pulps; the enamel covering a long and narrow external vertical face, and terminating above the alveolus, thus distinguishing crown and root. The superior incisors with the apex incased in enamel, which extends much farther on the outer than the inner side; the crown compressed, not wider than the root. The first superior incisor is large, and the crown is somewhat spoon-shaped. The second incisor is as robust as the first, but the crown is shorter. TJie second premolar has one external and one inter- nal lobe, in the third (fourth) premolar these lobes are much enlarged, and the tooth is transverse. The true molars have two external cusps, which •are flattened, close together, and well within the margin of the base of tlie crown. There is one internal lobe at the junction of two ridges, which in- close a triangular area with the connected bases of the external two cusps; and a strong posterior ledge, as in the opossums. Of the inferior incisors, the median is large and half gliriforni, while the first and third are small. The inferior, like the superior canines, are large. The first and second (third) premolars have no internal lobes, but the second (third) has a heel. The fourth is more or less like the first true molar. The inferior molars support two V's, witli rounded apices directed out- ward, the posterior soon wearing into a triangle lower than the anterior. The anterior is elevated and transverse, only distinguished from a triangle by INSECTIVOEA. 203 a notch on the inner side. Last lower molar with this anterior ti-ansverse triangle, a diagonal ridge, and a heel with raised border. The fourth premo- lar has a V-shaped crest on its anterior half, the angle being an elevated apex of the external face, the limbs descending inward. This genus diffei's from AncMppodus and Ectoganus in the far less gliri- form character of the incisor teeth, although the composition of the molar teeth exhibits a true resemblance to that seen in those genera. The incisor is annectant to the form usual in Mammals, betraying the rodent character in the absence of enamel from the posterior face, and the oblique bevel posteriorly from the apex to the shank. The ? canine or superior incisor (second form) is elongate, and without distinction between crown and root, but is straight, and not gliriform. A resemblance to the superior incisor of Ectoganus can be observed in the deep emargination of the enamel to near the apex on the inner side, and the convexity of the opposite side. A strong resemblance can be discovered between some characters of this genus and Totnitlierium, which is described under the Mesodonta. The composition of the inferior molars in the latter is essentially the same in the two genera, but the anterior cusps and yokes are relatively less developed in Tomitherium. An obvious resemblance is seen in the last premolar, which is somewhat sectorial in the form of its anterior half in both genera. There is no enlarged external incisor in Tomitherium, but either arrange- ment is consistent with mesodont aflfinities, and even incisors of rodent-like character, in view of the structure of Chiromys. Its resemblances to Eri- naceiis are, however, so many that I leave it in the neighborhood of that genus. The premolars of the superior series are nearly alike in the two genera, and so are the inferior molars, excepting the last, which is much smaller in Erinaceus. The superior molars of the hedge-hogs only differ in the development of the posterior cingulum into a posterior internal cusp, which is connected with the posterior external cusp by a transverse ridge. It is probable that this genus represents the group ancestral to the existing Erinaceidoe. 204 EOCENE FAUN^. The following points may be derived from parts of a skeleton of E. hurmeisteri. The i)rocessus dentatus of the axis is short and obtuse, and has an oval section. The doi-sal vertebrae are much smaller than the cer- vicals, and the tubercular articulation is on a long diapophysis. The cau- dals are very large. The scapula has a prominent coracoid hook. The manus has five digits. The scaphoid is larger than the cuneiform, and is di.stinct from the lunar. The trapezium is large and distinct; unciform large. The phalanges are like those of Creodonta. The ilium has a narrow plate with strong external ridge, which makes the section of its peduncle an equilateral triangle. There is a large anterior inferior spine. The distinctness of the scaphoid and lunar bones and the five digits of the manus show that this genus cannot be referred to the family of the JErinaceidce, but to belong rather near to Solenod&n, and perhaps within the boundarie.s of the Centetklce. The specimens show that my original determinations of the incisors based oh loose teeth were correct. They also show that this genus is not far removed from the Creodonta. 0 There are several species of the genus, wliich I define as follows: I. Fourtli inferior premolar like first true molar. Larj;;er; third .superior piemolai* larger; fourth i)remolar with the external cuspbilob- ate E. acutidens. Jledium; third sni)erior i)remi)lar .smaller; fourth premolar with external cusp .simple; .sui)erior incisors wide; large inferior narrower E. burmeisteri. Medium; superior iiK.-isors narrow; large inferior wider U. bisulcatus. II. Fourth inferior premolar with anterior V open and cutting. Smallest; incisors unknown E. acer. A species of the size of E. acer has been named E. S2)atidariKS, but I cannot place it in the above key, as the premolar and incisor teeth are un- known. The section II approximates nearer the genus Conorydes than sec- tion I. ESTHONYX BURMEISTKRI Cope. Report Vertebrate Fos3., New Mexico, 1874, p. 7: Report U. S. G. G. Surv. W. of lOOtli Mer., G. M. Wheeler, iv, ii, p. 156, pi. xi, fig. 26. Plate XXIV6, figs. 1-10. A fractured cranium exhibits the entire dentition ot this species, and gives the characters satisfactorily. The anterior premolars are wanting. INSECTIVORA. 205 The third premolar consists of an external strongly compressed lobe and an internal keel or wide cingulum. The posterior third of the exter- nal lobe is reflected outwards, inclosing a groove Avith the anterior part. The latter rises into an apex, which is separated by an open notch from the posterior portion. The latter has a superior convex edge, and both lobes together present a convex face inwards. The internal lobe is low and sends a ledge continuous with its apex along the posterior base of the crown. Its prominence inwards gives the base of the crown a triangular outline. The fourth premolar is generally similar to the true molars in its trans- versely elongate form, and the production outwards of the anterior external base of the crown as well as the posterior external angle. It differs from them in that the principal external cusp is single and not double, and in the absence of a well-defined posterior internal ledge. On this account the internal angle is more nearly median than in the true molars. There are rudimental antei'ior and posterior cingula on the inner part of the crown. The principal cusp is compressed and acute, and stands well within the ear- like external expansions of the base of the crown. In the true molars there is a rudimental anterior cingulum. The principal cusps are compressed and well separated, though connected at their bases ; those of the first not more so than those of the second, contrary to Avhat is seen in E. acutidens. The posterior external ear-like lobe is a little longer than the anterior in the first molar; a little smaller in the second, and much smaller in the third. Enamel smooth. The inferior molars do not differ much from the corresponding teeth of E. bisidcatus. The anterior limb of the anterior V is not so elevated as the posterior limb, but more so than the posterior V. On the last molar the intermediate lobes are well developed, but the external is much the larger. The anterior V of the fourth premolar has not as great transverse extent as the anterior V of the true molars, but it is well developed, and not a cutting lobe, as in E. acer. The third premolar has an anterior cutting lobe and a posterior keel with a cutting edge continuous with that of the principal lobe. The anterior edge of the latter is convex and rises to the acute apex. The second (first) premolar is two-rooted ; crown lost on both rami. The inferior canine has a robust base, and issues close to the first premolar. Crown broken^ 206 EOCEXE FAUNiE. oflf. The third incisor is a small tooth with small truncate crown, and enamel on the external face only. The second incisor is compressed, and has an elongate crown with the anterior face convex in both directions. The posterior edge is beveled like that of a rodent, but has a thin investiture of enamel, which is worn away by use on a low median ridge. The sides of the crown are covered with enamel. The external side is regularly convex; the inner one is flattened. The first incisor is much smaller than the second, and the sec- tion of the crown is sub round, and narrowed to an angle posteriorly. It is as long as the second incisor, and therefore much longer than the third. The symphysis is coossified and is nearly horizontal in its direction, its plane making an acute angle with the alveolar line. As a consequence the incisor teeth are directed forwards at the base, curving slightly upwards at their summits. Measurements. u. Length of posterior five molars 047 Length of true molars 026 Diameters p.-m. in 5 anteroposterior OOd ( trausverso OOd Diameters p. m. iv 5 anteroposterior 008 ( transverse 010 Diameters m.-ii S anteroposterior 009 < transverse 013 Length of inferior dental series (axial) 074 Length of inferior true molars 028 Length of inferior premolars 021 Diameter of base of canine 007 Length exposed anterior face m. ii 0115 Width posterior face I. ii 0035 Width posterior face I. iii 0020 Diameters p.-m. iii ^anteroposterior 0070 I transverse 0040 Diameters m. ii ^anteroposterior 008 ( transverse 0065 Diameters m. iii ^anteroposterior 0110 ( transverse 0060 Diameters crown superior 1. i \ '""S (oblique) 0080 I short 0055 Length of alveolus of I. ii 0090 Depth of mandibular ramus at m. iii 024 Depth of mandibular ramus at p. m. ii 014 Length of alveolar border of preoiaxillary bone 020 This species is well distinguished from the E. acutidens in the characters of the posterior premolar teeth of the superior series. In the latter, the external lobe of the third superior premolar is much longer, while the inter- nal lobe is smaller than in the E. hurmeisteri. The external lobe of the fourth ' INSECTIVORA. 207 has two lobes instead of one. I mention here that the loose tooth of the E. acutidens, which I figure Plate XXIVa, figs. 17-1 7a, as a first superior premolar, may not really be such, but may be a second superior incisor. From E. Msulcatus, which I discovered in the Wasatch region of New Mexico, this species is separated by the much longer superior incisors and smaller inferior second incisors. Part of the skeleton of a second specimen includes the superior pre- maxillary bone with the second incisor of the right side; parts of the mandible with three incisors and the posterior four molars; vertebrae from various parts of the column; parts of the scapula humerus, manus, pelvis, ribs, and fibula. The generic characters observable in this specimen have been already recited. The atlas is characteristic. The transverse process is on the posterior edge of the vertebra,- and its inferior edge is narrow. It is perforated from before upwards and backwards by the vertebral canal. The lateral canal pierces the neural arch at the middle of its external border. The anterior border of the arch is notched medially. No neural spine. The axis is quite robust and the neural arch is large. The neural spine is elevated and has not an elongate base. The paradiapophysis is small. The inferior me- dian line is keeled. The processus dentatus is constricted at the base above by a groove; its superior face is quaquaversally convex. The posterior articular face is wider than deep, and is oblique. A more posterior cervical centrum has oblique transverse articular faces about as wide as the body is long. The inferior face has a median keel with a concavity on each side. The centra of two dorsals, an anterior and a posterior, are depressed. The inferior median line is a flat band, which widens posteriorly. The two venous foramina of the neural floor are large. The caudal vertebra asso- ciated with the other specimens has no neural arch. It is very lai'ge, more than twice as long as the longest dorsal and one half longer than the axis with odontoid process. It has a ridge on each side, which terminates in a short process posteriorly, and a median ridge below, which terminates behind in a double tuberosity. If this vertebra belongs to this skeleton, the ani- mal had an unusually long tail. 208 EOCENE FAmf^. Measurements of vertebrtB, IL / vertical 018 Diameters of atlas < anteroposterior at side of arch (X*9 ( transverse without diapophysis 021 Uongitudinal J '^"^ <>^'"'«'''l •; ^-^ Diameters of axis < ( without odontoid Olb I-., i-rtical to base neural spine 016 Diameters posterior face centrum axis. J ratis^erse < vertical 007 I anteroposterior 009 Diameters of anterior dorsal centrum. < vertical 0055 ( transverse ("OQ t anteroposterior (K^r, Diameters posterior dorsal centrum. < vertical 006 ' transverse OOSo I anteroposterior 02e5 Diameters caudal centrum. < „„af priori,. 5 vertical 003 ( ■ ' c transverse 0(i9 The glenoid cavity of the scapula is an oval, narrower next the cora- coid, and not produced at that extremity into a tuberosity. In the manus the cubito-carpal articulating surface of the carpus is not very convex in any direction. The proximal surfaces of the scaphoid and lunar bones are concave. The two proximal surfaces of the cuneiform are about equal; that for the pisiform the longer by a little. The scaphoid's greatest diame- ter is transverse. The transverse is the shortest of the lunar. The sizes of the anterior faces of the carpals of the second row are, in diminishing order, the unciform, the trapezium, the trapezoides, and least the magnum. The trapezium is wider than long, and extends distadt over the proximal extremity of the second metacarpal. The proximal extremity of .the second metacarpal is concave; that of the fourth is convex. The fifth has a proximal external tuberosity. Its shaft is proximately as stout as those of the others, which are of subequal proportions, but the second and fifth con- tract more rapidly. Measurements of fore limb. u. Width of extremity of scapula with coracoid 019 Diameters glenoid cavitv '"'*"''I'"«*''"'"" ^}^ l transverse CKnt Anteroposterior diameter humerus below head 013 Width of rarjuis 021 Liutjth of caritus alt trapezoides .008 I anteroposterior 0055 Diameters scaphoid < vertical in front 0045 ( transverse 008^ INSECTIVOEA. 209 M. I anteroposterior 007 Diameters lunar < vertical in front 006 ( transverse 005 I anteroposterior 006 Diameters cuneiform < vertical in front 004 ( transverse 008 c second : 005 Proximal -widths of metacarpals < fourth 005 ( fifth 0055 The ilium is slightly concave longitudinally on the external face. The inner border is abruptly contracted near the origin of the os pubis. The anterior inferior spine is prominent and extended with the length of the ilium; it is four times as long as wide. The groove of the acetabulum is within the anterior margin of the ischium. The posterior edge of the pelvis opposite to the acetabulum is not thinned nor expanded. A bone which may be the radius, or possibly the fibula, has marked peculiarities. The distal poi'tion has for a considerable distance on the inner side a median keel with a gutter on each side. The keel expands into the triangular articular facet. The rest of the shaft has an oval section. The external face of the head has two flat tuberosities, of which the external is much the larger, and has a concave posterior border. This bone is apparently too stout for the fibula and too slender for the radius. As one extremity is lost I cannot be positive as to its position. Its articular face fits the scaphoid and lunar bones. The inner face of the radius in Erinacevs is excavated, but has no keel. Measurements. M. Width of neck of ilium Oil Width of acetabulum 015 Width of neck of ischium 015 Width of (?) distal facet of (?) radius Oil Diameter of shaft of (?) radius near middle 006 The teeth are like those of the specimen first described. The second superior incisor has three sides of the crown ; a large extero-anterior convex, a wider interior, and narrower posterior, plane. The true molars measure .026 on their bases, and the ramus is .023 deep at the anterior part of the last molar. Several fragments of jaws were found by Mr. Wortman, besides the type specimen described, which are probably referable to it. All are from the Big Horn bad-lands of Northern Wyoming. No specimens of the E. acididens have been identified from that region, but several present the measurements of the E. spatularius. 14 0 210 TOE WASATCn AND BRIDGER FAUN^. ESTHONYX ACUTIDENS Cope. Bulletin U. S. Gcol. Surv. Terrs. F. V. Ilayden, 1681, p. 185. Plate xxiva.figs. 17-21. The largest species of the genus, and represented by two individuals. The first of these includes the last molars of both series and an anterior true- molar ; the second includes most of the dentition of one maxillary bone, the last two true molars being probably the only teeth missing. Four of the molars of this specimen are in ))lace, and three are loose. Under the cir- cumstances, I estimate six molars, of which the foui-th premolar is like the first true molar, and the third premolar has its internal lobe very much reduced. The two preceding premolars have one root, and short, com- pressed, and acute crowns. The second is abruptly very much smaller than the third, and is close to it ; the first is close to the second, and is a little larger. The canine is larger still, and is somewhat compressed. Externally viewed, it looks like the canine of a carnivorous mammal ; but viewed from within, it displays marked peculiarities. It has here a median rib, separated from the fore and aft edges of the crown by a groove on each side. This ridge is without enamel, and the edges are produced and very sharp. The enamel of the external face extends twice as far towards the base as on the interior side. The enamel of this tooth, with that of the premolars, is wrinkled ; that of the molars is smoother. The two external cusps of the last premolar are closer together than those of the true molare. The posterior part of the external basal cingulum of the second and third true molars is more prominent tlian the anterior part. The details of the inferior teeth preserved do not difiFer much from those of the E. bisulcatus, excepting that the heel of the last true molar is much more produced. The E. acididens is considerably larger than either of the species of the genus heretofore described. Measurements. No. 1. M. lertical 00r>5 Diameters of last inferior molar^ antero-postcrior 0130 transverse 0064 ^. . - . , C antoro-po.sferior 0095 Diameters of u I mo molar { . „~., I triinsverse wrii r< ar < tr 0- Vf _..,,, , < anlero-poHtcrinr 0097 Diameters of Jaat buperior iiioliir ? _ _ q.o- MESODONTA. 211 No. 2. M. liengthof five superior molars preserved 0410 Length of premolar series 0325 Length of bases of Pm. I and II 0125 „. . „ „ -., ( antero-posterior 0097 Diameters of Pm. Ill < ^ ' < transverse 0098 T.. . 1. J. i , , c antero-posterior 0086 Diameters of first true molar K „.„,. J transverse 0133 Antero-posterior width of base of crown of canine 0080 Transverse width of base of crown of canine 0050 Wind River Basin, Wyoming. J. L. Wortman. EsTnoNYX sPATULARius Cope. American Naturalist, 1880 (Nov. 25), p. 908. Plate xxiv a, figs. 22-25. Represented by five molar and premolar and two incisor or canine teeth, apparently belonging to one individual. These are about the size of those of E. bisulcatus, but present several differences of detail. Thus the basin of the heel of the last inferior molar is not obliquely cut off by a crest which extends forwards fi-om the heel, but is surrounded by an ele- vated border, which rises into a cusp on the external side. The incisor- canine teeth are more robust than those of E. bisulcatus, one of them espe- cially having a spoon-shaped crown, with the concave side divided by a longitudinal rib, on which the enamel is very thin. The enamel descends much further down on the external than the internal side of these teeth. The rodent-like tooth does not accompany the specimen. Length of base of last inferior molar, .009; width anteriorly, .005; length of crown of canine incisor No. 1, .009; width at base, .005; length of crown of second canine incisor at base, .012 ; width, .006. Basin of the Big Horn River, Wyoming. J. L. Wortman. MESODONTA. Since 1872 the Eocene formations of the Rocky Mountains have been known to contain the remains of numerous species of Mammals which pos- sess greater or less proportions of characteristics of the order Quadrumana. Some of these were referred by their first describers to the Insecfivora, and others to the Ungulata. In October, 1872, the writer described a genus, 212 TUE WASATCH AND BEIDGER FAUN^. Anajitomorphus, represented by a jaw found in the Bridger beds of Wyoming, in wliose dentition Quadrunianous characteristics are so marked as to have induced me to comj)are it with such typical forms as Simia. The characters of the mandibular dentition then recorded are those of the true monkeys, but the permanent separation of the mandibular rami distinguishes the genus from these and from the marmosets, constituting a resemblance to the lemurs. The dental formula is I. 2 ; C. 1 ; P. M. 2 ; M. 3 ; the crowns of the pre- molars with a single, undivided, compressed tubercle. In the following year I published (May 6, 1873) a second paper, in which the characters of Anaptomorphus and of the earlier described TomUherium (Cope) were more fully elaborated. In this essay I refen-ed* the latter genus also to the Quad- rumana, but as expressing a t}'pe even more aberrant than the Lemurs, and therefore well separated from the true monkeys. I cited, as reasons for this reference, the flat ilium, the long femur, the round head of the radius, the form of the distal end of the radius, with the coossified symphysis and four transverse incisors of the lower jaw. I pointed out that the forms of the molars are similar to those of the Quadrumana, and to animals of some other orders as well, while the number of molars is greater than in the Lemurs, or any other known group of the order. The formula of the mandible is I. 2 ; C. 1 ; P. M. 4 ; M. 3. I also pointed out the resem- blance between this genus and Hyopsodus, which was then estimated as Ungulate, but which has since been stated to be Lemurine. Finally, I added to this series, in the same year,t the genus described by Leidy as Nothardus, and a foiirth species, which belongs to tlie genus Pantolestes Cope. In the Actes of the Linna'an Society of Bordeau.x fur 1873, J M. Del- fortrie publislied a description of the cranium of a Mammal which he named Palceolemur betiUei, which he referred to the Lemurs, pointing out certain differences. He gave a number of characters which he deemed sufficient reasons for such a course. Chief among these are the completed orbits, directed partially forwards, which are associated with elongate nasal bones, large petrous bone, and acutely tubercular molars. M. Dclfortric also points •Oil the Primitive Types of tliu Miitiiiiiiili.a Kdiieiiliilia. t Aiiiimil Keport U. S. Gcol. Siirv. Terrs., Itf7-J (pub. 1873), p. 5-19. tAiiii. So. GiSol., t. iv,N(). iv, p. 18, pi. vii, viii, 1874,niMl Jounial de Zoologio, iv, p. 4C-I. MESODONTA. 213 out that the dentition differs from that of the known Lemuridce in the more numerous premolars, giving the following formula: I. ?2; C. 1; P. M. 4; M. 3 ; or the same as that of Tomitherimn. At the time of the discovery of Anaptomoriyhiis, Prof 0. C. Marsh expressed the opinion* that some of the forms noticed by him in the Bridger formation of Wyoming are allied to the Lemurs. He, however, did not state the characters which led him to entertain this opinion, nor did he give such descriptions as would enable the anatomist to judge of its correct- ness. Up to the present date no more complete account of these animals has appeared. The history of discovery of the European forms of this group is simi- lar to that of our own, in respect to the difficulty at first experienced by paleontologists in referring them to their proper systematic position. The investigations conducted by Cuvier during the early part of this century into the extinct Vertebrata of the Eocene of the neighborhood of Paris revealed, among other types, the genus Adapts (Cuv.). This he referred to the Ungulates and to the neighborhood of Anoplotherium. Laurillard and Blainville believed that its affinities were to the Insectivora. The above- mentioned discovery by M. Delfortrie, of Bordeaux, of the greater part of the cranium, at Bebuer (Department of Lot), of his Palceolemur hetilleij-f led him to announce that Lemurs inhabited France during eaidy Tertiary times. This was in confirmation of the opinion of M. Riitimeyer, who had already described a Coenopithecus lemuroides from the Eocene of Switzerland. But MM. Gaudry and Gervais, on further investigation, came to the conclusion that the Palceolemur is the Adapis of Cuvier, and that Aphelotlierium Gerv., and Coenopithecus, are also synonyms of it. And they are disposed to accede to the conclusion of Delfortrie as to its affinities. Subsequently M. Filhol established for this genus, and a new one which he called Necrolemur, a family, the Pachylemuridce, adding a new species, Adapis magnus. In this paper he recognizes the characters pointed out by previous authors as ally- ing this family to the Lemuridce, as well as the higher dental formula which * Amer. Jour. Sci. and Arts, Oct. 8, 1872. t Actes de la Soci(5t6 Liun<5eiiiie de Bordeaux, xxix, 1673. The separate copies of this paper are 'dated May 25, 1873, while a supplement attached to the last page is dated September 4, 1873. 214 THE WASATCH AND BRIDGER FAUNiE. distinguishes it, and adds some important characters which are strongly marked in the genus Adapts. He tinds the cranium to be strongly con- tracted just behind the orbits and at the pterygoid plates, in a manner unknown to existing Lemuridce. Subsequent to the above dates the number of known species of these puzzling Eocene Mammalia has been increasing, and the Wheeler expedition of 1874 added a number of genera and species to those previously known. An illustrated account of these was published in the final report of that organization, Vol. IV. I have seen no reason to modify the view originally expressed as to the Quadrumanous affinities of Anaptomorphus ; on the contrary they have been placed beyond doubt by the discovery of the entire cranium by M. Filhol, of his genus Necrolemur above mentioned, which is very similar to Anaptomorphus, in the parts of both which are known, the mandible and its dentition. Additional light was thrown on the structure of Tomitherium by my researches in New IMexico, conducted in 1874. The fragments of the skeletons of two species of a closely allied genus, Peli/codits, were found, which include numerous bones of the tarsus, and these are identical with corresponding parts in the Creodonta and different from those of the Lemuridce. The astragalus extends anterior to the shortened calcaneum, and the navicular is short and the cuboid not elongate. The superior aspect of the astragalus presents two oblique surfaces, one for the internal malleolus, the other for the transverse facet of the tibia. The portions of femur, including the third trochanter, the proximal part of the ulna, and the distal portion of the humerus, are nil closely similar to those of the Creodonta. The type specimen of Tomitherium includes some parts of the skeleton not present in the New Mexican species. Thus the ilium of T. rostratum, while furnished with the prominent anterior inferior spine of the Creodonta, is flat- tened toward the crest, and is not angnlate on the external face. The femur is furnished with a very elevated third trochanter, which is opposite to the little trochanter, as in Chirnmi/s and Talpa, and not low down, as in Creo- donta. The head of the radius is rounder than in Creodonta. The skeleton of Tomitherium, in fact, bears a strong resemblance to that of ChiromySy leaving the skull out of view. MESODONTA. 215 The skeleton of the New Mexican form includes an entocuneiform, like that of Stypolophus Mans, which indicates a non-opposable hallux. It is apparent that the supposed Lemurine Mammalia of the type of Tomitherium, which have the formula of the molar teeth 4-3, cannot be separated by ordinal distinction from the Creodonta. They differ from them, it is true, in their wholly tubercular molar teeth, but in this relate to them as the Bears and Procyonidoi do to other Carnivora. I have, therefore, pro- posed* to constitute these a distinct group or suborder, intermediate in position between the Creodonta and the Prosimice, under the name of the Mesodonta. I cannot now find characters by which to distinguish this divis- ion from the Insectivora as an order. In my report to Dr. Hayden on the paleontology of the Bridger Eocene of "Wyoming.t I included six species, viz, Tomitherium rostratum, Pantolestes longicaudus, Sarcolemur furcatus, S.pygmceus, Hyopsodus vicarius, and H. pauliis Leidy, which belong to this suborder. As many species of Mesodonta referred to various orders are described by Dr. liCidy in his quarto report in the same series. In my report to Lieutenant Wheeler on the Vertebrata of the Eocene of New Mexico obtained by the expedition of 1874, eleven species are included, none of which had been certainly obtained from the Bridger beds. A synopsis of the genera is given below, in which the characters are derived from the dentition of the lower jaw, the pai-t usually preserved. While considerable variety is to be observed in the structure of the teeth, they furnish also close approximations, so that their discrimination requires careful scrutiny. The genus Anaptomorphus Cope, although included in the synopsis, probably belongs to the Prosimice. I. Last true molar with cusps in opposing pairs. A. Anterior inner cusps, two or a double one, on some of the molars. * Three premolars. "Last premolar without inner tubercle" (Leidy), like the other premolars Omomys. Last premolar with inner tubercle like the molars Microsyops. • * Four premolars ; last molar heeled. Last premolar without inner tubercle; premolars two-rooted.. Pantofesehind 0(W Length of true molar series 0136 Length of last true mol.ar 0052 Width of last true molar anteriorly 0030 Depth of ranins at third jjremolar 0090 Depth of ramus at last molar 0090 This species is dedicated to my friend Prof. WilHam B. Scott, of the College of New Jersey. TOMITllEKIUM Cope. Third Account of New Vertebra t a from tli<- Hridgrr Ko( cue of Wyoming, p. '2, August 7, 1W2 ; Proceed- ings American Philosophical Society tor 1H72 (pulilishcd .laiiuary, 1H72) ; On the Primitive Types of Mammalia Educahilia, 1873, May 6, p. 2; Animal Kcjiort U. S. Geol. Surv. Terrs., 1872, p. 456 (1873). Dental formula of the inferior series: I. 2; C 1 ; Pm. 4; M. 3. The last molar has an expanded heel. The third premolar consists of a cone with posterior heel; the fourth premolar exhibits, besides its principal cone, an interior lateral one, and a large heel. The true molars support two MESODONTA. 219 anterior tubercles, of which the inner is represented by two distinct cusps in one or more of them, and the external is crescentoid in section. The posterior part of the crown is wide and concave, and is bordered at its pos- terior angles bv an obsolete tubercle on the inner and an elevated anffle on the outer side. In the T. rostratmn, the type of the genus, the middle incisors have transverse cutting-edges. This genus is allied to Adapis Cuvier, of the French Eocene, bvit differs in the possession of but two incisors on each side; in Adapis, there are three, according to Filhol. From that genus and Opisthotomus, it differs also in the structure of the last inferior molar, as exhibited in the analytical table. An account of the osteology of this genus, so far as indicated by my material, was given in the papers above refen-ed to. It was shown that the hind limbs, especially the femur, are quite elongate, more so than the fore limbs, and that the proportions of both fore and hind limbs are slender. The head of the radius is subround, and its distal extremity a subequilateral triangle. The humerus is distally expanded, with large inner and outer epicondyles and an arterial foramen. The tuberosities of its head are small. The ilium is rather narrow and flat, except at the acetabulum, where it supports a large anterior inferior spine. The first impression derived from the appearance of the lower jaw and dentition, and from the humerus, is that of an ally of the coati {Nasua). The humerus, indeed, is almost a fac-simile of that of Nasua, the only difference being a slight outward direction of the axis of the head. The same bone resembles also that of many marsupials, but the flat ilium, elevated position of dental foramen, and absence of much inflection of the angle of the lower jaw, etc., render affinity with that group highly improb- able. The length of the femur indicates that the knee was entirely free from the body as in the Quadrumana, constituting a marked distinction from anything known in the Carnivora, including Nasua. The round head of the radius indicates a complete power of supination of the fore foot, and is different in form from that of Carnivora, including Nasua ; and, finally, the distal end of the radius is still more different from that of Nasua, and resembles closely that of Semnopithecus. 220 THE WASATCn AND BKIDGER FAXING. We have, then, an animal with a long thigh free from the body, a manus capable of complete pronation and supination, and details of lower jaw and teeth quite similar to that of the lower monkeys. The form of the humerus and its relative length to the femur are quite as marked as in some of the lemurs. The most marked difference is seen in the increased number of teeth; but in this point it n-lates itself to tlie other Quadrumana, as the most ancient types of Carnivora and Ungulates do to the more modern; e.g., Hycenodon to the former and Palceosyops to the latter. Through the great kindness of Dr. Filhol I came into possession of a mandibular ramus of the Adapls parisiensis Cuv., with nearh- entire dentition. The specimen was derived from the Phosphorite beds of central France, whose remarkable fauna has been so fully elucidated through the labors of M. Filhol. I cannot distinguish the characters presented by this jaw from those of the genus Notharctus of Leidy, although the species on which the latter was based is di.stinct from A parisiensis. Until some distinctive character is discovered, I use the oldest name. Adapts, for the genus. In the American Journal of Science and Arts for July, 1871, Prof. 0. C. Marsh gave a generic name, Limnotherium, which was accompanied by a description in which the characters of species and genus were not distin- guished, nor were the grounds of separation from other genera previously described, set forth. For these reasons I have been unable to identify the genus, or use the proposed name. Some years later Professor Marsh stated that the genus he thus referred to, is the one I have called Tomithe- rium.* As the name proposed by Marsh was not accompanied by a distinct and separate diagnosis I cannot adopt it, although in this instance its author includes in his description a greater number of generic characters than customary witli liim. Some of these characters are not applicable to TomitheriuDi, if the language of the description is to be literally understood. Thus, the e-xternal tubercles of the inferior molars are called cones, a term only applicable to the inner tubercles in the present genus. Nothing is said also of the third inner tubercle found in one or more of the molars, a character I thiidc to be generic in this group. Professor Marsh also .ascribes large canine teeth to the typical species he describes. They- are • American Jounial of Sciuuco ami Arte, 1875, ji. 239. MESODONTA. 221 quite small in the type of Tomitherium, but the character may be one of specific value only. The additional species referred to this genus in my report to Lieut. G. M. Wheeler on the vertebrate fossils of New Mexico belong to the allied form Pelycodiis. Tomitherium rostratum Cope. Paleontological Bulletin No. 3, p. 2, Aug. 7, 1872. Proceed. Amer. Philos. Soc., 1872, p. 470. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 548. Plato XXV, figs. 1-9. The portions of the skeleton of the type species preserved are : the entire dentition of the lower jaw, minus the crowns of the outer incisor, canine, and first premolar, the left ramus nearly complete, the extreme angle being wanting ; the right humerus complete, with right ulna and radius, the latter lacking the distal extremity ; a large part of the left ilium ; the right femur nearly entire ; part of the left humerus, metatarsals, etc. This species was about the size of the Cehus capucinus. The first and second premolar have but one root, the base of the second being about the size of the base of the canine. The latter are cylindric at base. The incisors form a parabolic outline, and have entire edges, the middle pair transverse ones. Enamel generally smooth, premolars somewhat striate ; an indistinct inner cingulum. The mandibular rami are quite stout, but not very deep ; the syra- physeal portion long and oblique, and the coronoid and condylar portions elevated, with axis at right angles to that of the horizontal portion. The condyle is well elevated, and the coronoid process small ; the dental foramen is half way between the margins of the ascending ramus, and opposite the bases of the crowns of the molars. The inferior margin of the jaw shows no tendency to inflection at a point immediately below this foramen, where it is broken oft'. The mental foramen is divided, the exits being at points opposite the fissures between the premolars 1-2 and 2-3. The humerus has a round head directed backwards and a little out- wards. The tuberosities are rather small, of about equal size, and obtuse; they inclose a short bicipital groove. The bicipital crests are very largely developed, and extend to the middle of the shaft, inclosing an open groove between them. The external is narrow and most elevated, the internal 222 THE WASATCH AKD BKIDGER FAU^^. more obtuse and directed inwards. The shaft is thus subtriangular in section. The distal extremity is nearly at right angles to the axis of the proximal, and is much expanded transversely. A large part of this expan- sion is caused by the truncate internal tuberosity, and by the less prominent external one. The latter is continued in a thin ala, which only sinks into the shaft at its middle. The condyles are small, the external the most prominent. There is a shallow olecranar fossa, and no coronoid, and hence no supercondylar foramen. There is a large arterial foramen above the internal tuberosity. The ubia is compressed, and contracts rapidly towards the distal ex- tremity. The olecranon is broad and obtuse and the humeral cotylus oblique to the long axis. The coronoid process is low. The shaft is curved from right to left (inwards), perhaps by distortion. The radius has a discoidal head with central depression, and it was evidently capable of complete rotation. It exhibits a tuberosity and slight flexure below the head. The distal extremity has a horizontal triangular section with the apex internal and truncate; the shaft near it is quite flat. The carpal articu- lation is a simple, shallow concavity. The left ilium is obspatulate and flat, widest at the convex crest, and slightly concave on the outer side. It is rather thin, and the impression for the sacral diapophyses is elongate. The inferior border thickens gradually to the acetabulum; the superior is excised so as to form an open concavity. The right yewwr is remarkable for its length. Its shaft is flattened from before backwards, and without flexure. The great trochanter is large, and embraces a deep in-looking fossa. There is a flat tuberosity (third tro- chanter) looking outwards just below, and the little trochanter is a little below opposite to the latter. The condyles are subsimilar in size, the trochlear surface wide, but not flat, and the inner border thickened and considerably elevated. The femur is 1.75 times as long as the humerus; it was scarcely longer, though a small piece is wanting from the shaft of our specimen. MeasuremetiU. it. Length of entire dental scries (straight) 044 Lcnglli of Hj-mphysis mandibali 020 Depth of ramus at svcood molar 010 MESODONTA. 223 M. Length of crown of second molar 006 Width of crowu of second molar 0045 Width between two second molars 014 Width between canines 005 Width of ascending ramus above dental foramen 016 Length of humerus 083 Diameter of head 013 Diameter of shaft at middle 0085 Diameter of distal end, transverse 023 Diameter of distal end, antero-posterior 0078 Depth of olecranon 009 Depth of ulna at corouoid 010 Diameter extremity of radius, proximally 009 Diameter extremity of radius, distally 010 Length of ilium from acetabulum 042 Width near crest 017 Length of femur preserved 137 Width just below neck 017 Width at middle Oil Width at extremity 019 Width of trochlea 009 Longest chord of condyles and trochlea 019 The following points may be gained by comparison with the skeleton of Lemur collaris (catalogue Verreaux). There is considerable resemblance in the details of structure of the molars from the third to the sixth, inclusive. Of course the anterior teeth differ widely in the two, and the last true molar of the Lemur has no heel. The principal difference in the humeri is seen in the superior size of the epicondyles of the T. rostratum, and the rather more robust character of the shaft. The proximal half of the ulna is deeper, and the olecranon is not so wide in T. rostratum. The proximal part of the radius is very similar in the two species, but the distal extremity is in the T. rostratum less transversely extended, and thicker anteroposte- riorly. There is also much similarity in the ilia. The crest is more extensive in T. rostratum, and the inferior border is thinner at its proximal part. Towards the acetabulum the increase in width of this border is similar, and the anterior inferior spine is as prominent. The resemblance between the femora amounts to identity of character; that of the T. rostratum is more robust The remains of this species were found together by the writer in the Bridger beds in an isolated spot on Black's Fork, Wyoming. Professor Marsh states (loc. cit.) that this species is the one he named Limnotherium affine in a paper in the American Journal of Science and Arts, 224 TOE WASATCH AND BRIDGER FAUNiB. the advance copies of which bear date August 7, 1872. This is also the day of pubhcation of the paper in which the name Tomitherium rostratum was proposed. Professor Marsh's description is extremely brief, consisting of five lines and six measurements. No fuller description from Professor Marsh's pen has appeared since. An elaboi*ate description of my own speci- mens appeared May 6, 1873, in a paper entitled "On the Primitive Types of the Orders of the Mammalia Educabilia," which was included in the Proceedings of the American Philosophical Society for that year. My original description was fuller than that of Professor Marsh, consisting of seventeen lines and seven measurements. PP:LYC0DUS Cope. Systematic Catalogue of the Vertebrata of the Eocene of New Mexico, Explorations and Surveys west of 100th Meridian, G. M. Wheeler, 1875, p. 13. Having received considerable accessions to my material, representing species which I have referred to this genus, I am of the opinion that the latter is distinct from Tomitherium, with which I formerly united it. The character on which I originally proposed it, the two-rooted second pre- molar, is constantly present in several species. I may add that the third trochanter of the femur in Tomitherium has the elevated position seen in Lemtcridoe, while in Pelycodus it has the position on the middle of the shaft, as in the Creodonta. The superior molars of Pelycodus tutus have the following characters : First, one-rooted ; second, two-rooted ; third, three-rooted. Crown of fourth transverse, with one external cusp, with base antero-posteriorly extended, and one internal cusp. The true molars possess two exterior cusps which are flat on the external face. The first and second have two internal cusps, and the third has but one. Of the inferior molars, the last has a well-developed heel. The anterior inner cusps of one or more of the molai"s are double. Tiie fourth premolar has an internal tubercle and a heel. The third has no internal tubercle. The heels of the true molars are not bounded by elevated cusps behind. I have pointed out in my report to Captain Wheeler that the tibio-tarsal articulation in this genus is, like that of most of the Creodonta, without trochlea. MESODONTA. 225 Comparison of the superior molars of four species which I have referred to Pelycodus, with two of Hyopsodus, reveal the following characteristic dif- ferences. In both species of Hyopsodus there are two distinct internal tuber- cles, and there is no distinct V extending from the intermediate tvibercles. That is, the posterior internal tubercle is not connected by a ridge with the anterior inner tubercle. There is no internal cingulum. In Pelycodus tutus and P. frugivorus, and presumably in P. jarrovii, there are two internal tubercles, of which the posterior is distinct from the internal cingulum, and the anterior inner tubercle is the apex of a V, which includes the interme- diate tubercles. In P. angulatus and P. pelvidens, the apex of the V is the only distinct internal tubercle, the anterior. The posterior is a part of a cingulum which extends round the inner base of the crown. In these two species there is no median external tubercle, while in the two Pelycodi first mentioned the external cingulum sends up such a lobe between the exter- nal cusps. The species o£ Pelycodus may be distinguished as follows: a. Posterior iuterual tubercle of superior molars distinct from the posterior cingu- lum. Length of true inferior molars on base, ™.019 P. jarrovii. Length of true inferior molars on base, ™.017 P. tutus. Length of true inferior molars on base, ™.015 P. frugivorus. aa. Posterior internal tubercle of superior molars, small, and a process of the pos- terior cingulum. Length of true inferior molars on base, "".024 P. pelvidens. Length of true inferior molars on base, "".012 P. angulatus. Remains of species of this genus are very common in the Wind River and Big Horn bad lands. They were originally found in the Wasatch beds of New Mexico, and have not yet been announced from the Bridger forma- tion. Pelycodus pelvidens Cope. Lipodectes pelvidens Cope, American Naturalist, 1681, p. 1019, Nov. 29. Plate XXIV tl ; fig. 3. The largest species of the genus, represented by a single right mandib- ular ramus which supports the posterior four molars. The species is readily 15 c 226 EOCENE FAUN^. distinguished from the other members of the genus by the great projection of the heel of the hist molar and its constricted forjn. The fourth premo- lar is also larger than in the other species, and has a large anterior basal tubercle, which is much better developed than in the other species. In the true molars the three anterior tubercles are well distinguished, and the anterior, though the smallest, is well on the inner side. The pos- terior inner cusp is a little larger than the anterior outer. In the first and second true molars the inner margin of the heel is elevated, inclosing a basin-like fossa, and rises into a flat cusp posteriorly. There is a small median posterior marginal tubercle, which runs into a posterior cingulum, and is wanting from the DeUafherium fundaminis. The tubercular has the three anterior cusps distinct as in Didymictis sp., while the heel is longer than in the known species of that genus. Its external border rises into a prominent cusp with triangular base. The fourth premolar has a small heel on the inner posterior side, and an acute anterior basal cusp. The priiiciiial cusp is robust and the basal portion is widely grooved posteriorly (apex lost). True molars with an external cingulum. Enamel obsoletely wrinkled. Length of true molar series, .024; of fourth premolar, .0075; length of last molar, .008; width of heel of second true molar, .005; length of crown of do., .007. A second specimen of this species includes a mandibular ramus which supported the last five molars, and a maxillary which supjiorted the last four molars, both evidently jjarts of the same animal. Tiie third inferior pre- molar, which is wanting in the type specimen, is present here. It consists of an elevated acute simple cusp, which has median anterior and posterior ridges, and a low internal ridge, which separates a lateral plane from a pos- tero-intenial plane. There is a rudimental anterior basal lobe and a short heel with transverse jjosterior edge. No lateral cingula. A third specimen consists of parts of the maxillary bones of one indi- vidual, which support the last four sujjerior molars in better preservation than those of the specimen described above, where two of the four are l)roken. The two individuals clearly represent one species. The fourth premolar is transverse, and consists of a principal large external cusp and a smaller MESODONTA. , 227 but well developed acute internal cusp. The external cusp is flush with external base of the crown, and is flanked by a small basal lobe both ante- riorly and posteriorly. These lobes are connected with each other by a weak external cingulum, and with the internal cusp by an anterior and a pos- terior cingula of greater strength. No intermediate tubercles. The true molars may be readily distinguished from those of most of the Creodonta, Deltatherium, for instance, by the presence of intermediate tubercles. The external cusps are low and well separated, and are not so far within the base as in Deltatherium and Dklelphys, though they are bounded externally by a low cingulum. The latter terminates in two angles, one anterior and •one posterior, which send inwards cingula, which meet in a prominent angle interior to the middle of the crown. These cingula support also the jntei'mediate tubercles. Another cingulum arises below the intermediate tubercles, and passes round the inner base of the crown, where it has a truncate outline, owing to the development of tubercular angles anteriorly and posteriorly. The differences between the true molars are as follows : The first is smaller than the second and larger than the third. The first and second have a strong tubercle at the posterior inner angle of the cingu- lum; in the third the cingulum only is present. The anterior inner angle ■of the cingulum is much more pronounced in the second than the first molar, and in the third it is not angulate, the inner extremity of the tooth being narrowed oval in outline. In this tooth the posterior external cingular angle is wanting, and the posterior external cusp x-educed in size. Measurements. M. -Length of bases of buperior true molars 0185 Diameters P-m. iv ^ '^°*''"'P°***«"'"' ^^'^ I transverse 0070 Diameters M. ii ^''"*'^™P°"*'^"'«" 0'^« transverse 0085 anteroposterior 0050 transverse, at middle 0062 This species was found by my assistant, Mr. D. Baldwin, in the Lower Hocene, probably Puerco beds of Northwest New Mexico. 228 EOCENE FAUN^. Pelycodus jarrovii Cope. Systematic Cntal. Vert. Eocene, New Mexico. U. S. Expl. Surv. W. of 100th Mer., 187.">, p. 13. Prololo- mu» jarrovii Cope, Ann. Rep. U. S. Geog. & Geol. Expl. Surv. \V. 100th Mer., in report of Chief of Engineers, 1874, p. 1"26. Tomitherium jarrovii, Rep. Expl. Survey W. of 100th Mer., G. M. Wheeler, iv, pt. ii, p. 137, 1877. Part of a mandibular ramus supporting the last two true molars from the "Wind River beds has the dimensions of this species, and is probably to be referred to it Pelycodus TUTUh Cope. Bulletin U. S. Geol. Surv. Terrs. 16^1, p. 187. Tomitherium tulum Cope, Report Expl. Snrv. W. of 100th Mer., under Capt. G. M. Wheeler, iv, pt. ii, p. 141. Plate XXVo, figs. 1-3. Jaws of six individuals of this species from the "Wind River beds are contained in my collection. Two of these include both rami of the mandi- ble, and two others a greater or less part of the superior dentition. In one of the latter most of the right premaxillary and left maxillary bones are preserved. The former is light, and supports only two teeth, and although the apex is broken away I do not believe in the existence of a third incisor. My belief is partly based on the wide spaces which separate the posterior incisor from both the anterior incisor and from the maxillary suture. The crown of this tooth, the only one preserved, is small, and is directed obliquely forwards ; its posterior face is concave, and the cutting edge is thin. The fourth superior premolar and all the true molars have anterior and posterior basal cingula, which on the last two true molars extend round the inner base of the crown. It extends round the external base of the four molar.s mentioned. The exterior border of the last molar MESODONTA. 229 is rounded, the posterior cusp having consequently a more interior posi- tion. Between each pair of external lobes a small tubercle rises from the cingulum, as in most ungulates with external crescents. The anterior inter- nal tubercle is connected with the anterior basal cingulum by an oblique ridge. The posterior inner tubercle is independent, and between it and the posterior external cusp is a low, angular tubercle. Like the posterior inner tubercle, this one is wanting from the fourth premolar. A loose canine from the same specimen has a sharp edge on the posterior border of the crown, which is terminated at the base by a small, acute tubercle. A longitudinal concavity bounds one side of the edge. The infraorbital fora- men opens above the posterior root of the third premolar. On the inferior molars of the same specimen, the second cusp of the anterior inner pair is rudimental on the last tooth, and distinct on the penulti- mate. The heel of the last molar is large, and its internal border is crenate, and the posterior border is notched. The three other lobes are robust. The lateral angles of the heel of the penultimate molar are prominent. No cingula on inner bases, traces only externally; enamel smooth. The last two pi-emolars are preserved in the rami of another specimen. Both are rather robust and have wide heels; that of the third very short. The latter has no anterior basal lobe; in the fourth it is a rudiment on the anterior cutting-edge. The latter has an internal tubercle; the third has none. Measurements. No. 1. M. Length of superior molar series 0280 Length of superior premolars 0150 Length from second (first) incisor to maxillo-premaxillary suture 0060 „. , , „ , , (anteroposterior 0048 Diameters of fourth premolar/ , „^„ ' J transverse 0070 „. . . ,, , (anteroposterior 0060 Diameters of second true molar ? . „.„„ ( transverse 0080 „. , „ , , , , (anteroposterior 0050 Diameters of last true molar { . ^„ I transverse 0065 No. 2. Length of bases of Pm. Ill, IV 0095 I anteroposterior 0050 Diameters of Pm. IV< transverse '. 0040 ( vertical 0038 From collections made by Jacob L. Wortman. 230 EOCENE FAUyiE. Pelycodus FRUGivoRiJS Cope. 878t«matic Catal. Vert. Eocene New Mexico, U. S. Gcog. & Geol. 6uT\. W. of UKMli Mer., Iir75, p. 14.. Tomithcrium fntghorum Cope, Report U. S. Geog. & Geol. Expl. Surv. W. of lOOtli Mer., Capt. G. M. Wheeler, iv, pt. ii, p. 144. Pehjcodui nunicnum Cope, BullctiD U. 8. Geol. Suit. Terrs. 1^*1, p. 187. Plate XXV a, figs. 4-5. This species was not rare during the Wind River epoch of tlie Eocene in Wyoming. Fragmentary jaws of six individuals of this species were- found by Mr. Wortman. The best preserved ramus supports all the teeth posterior to and includ- ing the third premolar. The last-mentioned tooth has an elevated acute crown, without any anterior basal tubercle, and a very short posterior heel. The fourth premolar is very stout; its cusjjs are not much elevated, and the heel is short. The anterior basal tubercle is quite small. All of the- tnie molars have a second cusp in front of the anterior tubercle, but it is quite small, excepting on the first, where it is more distinct. The external crescents of all the molars are well defined, but the posterior does not inclose the crown behind with an extension of its horn. The last molar is a little longer than the others, and its posterior border is produced into two cusps. A simple raised border is found here in the typical specimen or P. frugivorus. * Measurements. M. Length of molar series from third premolar, inclusive 0228 Length of true molars 0150- „ „„ , (anteroposterior OOoO Diameters of first true molar } . nnoa ( transverse 0038 „. „, , (anteroposterior 00(55 Diameters of last true molar? . nnm < transverse 0040 Depth of ramus at Pm. Ill 0095 Depth of ramus at last true molar 0095 The character of the last molar above mentioned distinguishes the four specimens of this species where that tooth is preserved, from the type of P. frugivorus. I originally looked on these as representing a dis- tinct species on this account, and called it P. nunknum, but further investi- gation will be necessary in order to asceilain whether this course was justifiable or not. A series of superior molar teeth accompanying the lower jaws and bones of PUsiardomys ddkatior, so strongly resembles those of Pelycodus MESODONTA. 231 tutus that I am induced to refer them to the P. frugivorus, with which they agree in size. They differ from those of P. delicatissimus in possessing an external basal cingulum and only one principal external cusp of the fourth premolar. The posterior molar is also abbreviated posteriorly, as in P. tutus. As compared with that species, the intermediate tubercles are less distinct, though present, and the inner basal cingula are weaker. The fol- lowing measurements show the smaller dimensions: Measurements. M. Leogth of last four superior molars 0160 Diameter8fourthpreinolar^='°*eropo8terior .00:« < transverse 0055 Diamteters second true molar J ''°^<''°P''^**"0'^ 0050 ( transverse 0070 Diametersthirdtruemolar^''"f^""P''^*''"'"' " - -OO^" ( transverse 0058 The infraorbital canal is contracted and long, and issues above the third premolar. This proves the fragment not to be rodent. This species is abundant in the Big Horn bad lands. Mr. Wortman obtained there two entire mandibles and seven separate rami which agree in all respects with the typical specimens. He obtained three mandibular rami in which the molar teeth measure .016 in length; that is, intermediate between the P. frugivorus and the P. tutus. Of the latter species Mr. Wort- man discovered four mandibular rami. One ramus shows a length of .018 for the true molars, which are therefore intermediate in size between the P. tutus and P. jarrovii. It will be necessary to study other parts of the skel- eton in order to ascertain the status of these individuals. Pelycodus angulatus Cope. Systematic Catal. Ent. Vert. Eocene, New Mexico. U. S. Geog. Surv. W. of lOOth Mer., 1875, p. 14. Re- port U. S. Geog. Siirv. W. lOOth Mer. iv, pt. iii, p. 144, pi. xxxix, fig. 15. Plate XXIV d; fig. 4. The P. angulatus, originally known from New Mexico, is represented in the Big Horn collection by four mandibular rami, and a portion of a maxillary bone with teeth. The inferior molars present much the appearance of those of the larger species. The anterior inner cusp is well developed, and nearly on the inner border of the crown, though not so large as the other anterior cusps. The 232 EOCENE FAUN^. posterior basin-like heel is wide, and is bounded on the external side by an angular crest. A cusp rises from the posterior inner angle, which is sepa- rated from the anterior cusp by a deep notch. There is a small posterior marginal tubercle at its external base. The heel of the fourth premolar is wide, and has a low cusp at each posterior angle. There are but two ante- rior cusps, the external of which is the larger, and is situated anteriorly to the well develo^ied inner one. The last inferior molar is lost from this spec- imen. The mandibular ramus is compressed and rather deep, and becomes deeper anteriorly. The symjihysis begins below the fourth premolar and was not coossified, although the animal is clearly adult. Measurements of mandible. If. Length of posterior four molars 0160 Length of true molars 0120 Length of base of last molar 0046 Diameter, m. ii ^ ''"*"''P°«'«"°'' !^^^ t transverse 0030 Diameters Pm. iv J ''""^■•°P''«'«"°'^ f^l (. transverse 0028 Depth ramus at Pm. iv 0078 Depth ramus at M. iii 0086 Associated with some of the mandibular fragments, but not known to belong with any in the same skeleton, is the fragment of upper jaw above mentioned. It supports the first and second true molars, in perfect preser- vation. They dififer from those of Hyopsodus vicarius (Plate — , fig. — ), which are of about the same size, in their rather more triangular form. This is due to the reduction of the posterior inner tubercle to a mei'e ledge sup- porting a small cusp. The anterior cusp is prominent, and is connected by ridges with two small angular tubercles on the anterior and posterior mar- gins of the crown. The external lobes stand on the external border of the base, are distinct, acute, angular, and with lenticular section. Their exter- .nal base is bounded by a cingulum which rises into a low cusp opposite the interspace between them. Slight anterior and posterior cingula. Measurements. Length of base of M. i ami M. iii 0070 I anteroposterior 0040 Diameters M. ni, transverse 0045 ( vertical 0020 e MESODONTA. 233 SARCOLEMUR Cope. Proceed. Acad. Nat. Sci. Phila., 1875, p. 256. Molars 4-3, the last with heel; crowns of true molars of four oppo- site or slightly alternating tubercles, the external pair slightly crescentic in section ; anterior inner tubercle bifid. The premolars are compressed, the last acute and with an acute inner tubercle. This form differs from its nearest ally, Pelycodus, in the development of acute cusps on the heels of the true molar teeth. The same character distinguishes it from the other genera here enumerated, excepting Hyopsodus. But this genus has the anterior inner tubercles simple. The type is S. pi/gmceus Cope (Antiacodon furcalus Cope, Annual Report U. S. Geol. Surv. Terrs., 1872, p. 608); another species is the S. mentalis Cope (Systematic Catal. Vert. New Mexico, 1875, p. 17). S. crassus, he. cit., belongs to some other genus, Mesodont or Creodont. Saroolemur pygm^us Cope. Proceed. Acad. Phila., 1875, p. 256; Lophiotherium pygmcBum Cope, Proceed. Amer. Philos. Soc, 1872, extras July 29; Syopsodua pygmceus Cope, loc, cit., p. 461; Antiacodon fiircatus Cope, Ou some Eocene Mammals, etc., p. 1, March 8, 1873. Annual Report U. S. Geol. Surv. Terrs., 1872, p. 608, 1873; Saroolemur furcatus Cope, Proc. Phila. Acad., 1875, p. 256. Plate XXrV, figs. 18-19. Represented by a portion of the right mandibular ramus, with the penultimate and antepenultimate molars in perfect preservation. These teeth present four cusps, of which the outer are crescentoid in section, the inner conic. They are all elevated, and the inner anterior is in both teeth compressed and bifid. It receives an oblique ridge from the outer posterior crescent, which also sends a ridge to the posterior inner. Enamel smooth. Measurements. M. Length of penultimate molar 0045 Width of penultimate molar behind 0040 Depth of ramus at posterior margin of penultimate molar ^ 0070 The typical specimen of the S. pygmoeus is a part of the right ramus mandibuli, with the three molars and last premolar in perfect preservation. The crowns of the molars are composed of two external chevron-shaped tubercles, the apices rising as acute cusps, and two internal cones, the 234 WASATCH FAUNA. interior of which is flattened and strongly bifid, both points being more elevated than any of the others. The cusps are nearly opposite to each other, and behind the interval between the two posterior rises another, not so elevated as the others, except on the posterior molar. Here it is elevated, and nearly equidistant from the two in front of it. The enamel is smooth, and there is no cingulum on either side. The premolar consists of a prin- cipal sectorial cusp, and has a smaller but stout acute anterior cusp, with a small rudiment of another behind; a stout cusp rises from the inner poste- rior margin of the principal one, giving it a subbifid appearance. Measurements. u. Length of four molare 0195 Ltngtli of three true molars 0149 Length of last true molar 0055 Length of first true molar 0043 Width of first true molar front 0025 Width of first true molar posteriorly 0031 Depth of ramus at front of M. 3 0075 Depth of ramus at front of Pm. last 0055 This species differs from the following in the presence of the posterior tubercles on the M. 2-3, and the absence of external cingulum. The sizes are not ver}" differnt. From the bluffs of the Upper Green River. This Mammal is about equal in size to a weasel. Fi-om Cotonwood, Wyoming, near Fort Bridger. HYOPSODUS Leidy. Proceed. Acad. Nat. Sci. Phila., If^'l; Geol. Surv. Montana, 1871, p. 3(52. The dentition of tlie mandible is in this genus characterized by the simplicity of the anterior inner tubercle, and the development of cusps at the angles of the heels of the molars. The fourth i)remolar has the usual internal cusp at the side of the external. The dentition of the maxillary bone is characterized by the presence of the full number of premolars, of which the last two at least have a well developed simple internal lobe. The internal lobe of the true molars is double, and there are two small inter- mediate tubercles. The external cusps are two, distinct and compressed. MESODONTA. 235 and stand on the external base of the crown. The third true molar does not differ materially from the second. Though the species of this genus are not numerous, individuals of two of them are exceedingly common in the Eocene beds of North America. The species of this genus known to me by their mandibles are five, and these differ chiefly as follows: a. Posterior inner cusps of inferior molars, elevated. Length of true molars M. .0175 ; last molar elongate R. powellianus. Length of true molars M. .0165; last molar elongate R. lemoinianus. Length of true molars M. .0140; last molar longer than second H. paulus. Size as last; last molar shorter than second H. miticulus. Length of true molars M. .0115; last molar elongate . H. vicarius. aa. Heel of true molars i and ii, basin-shaped, without posterior inner cusp. Length of inferior true molars M. .010; last molar as long as penultimate, .if. acolytus. Hygpsodus powellianus Cope. Plate XXIIId, figs. 3-4. The largest species of the genus is represented by more or less imper- fect mandibular rami of eleven individuals, none of which unfortunately support premolar teeth. The characters of the true molars are those of the other species of the genus. The cusps alternate with each other, and are quite acute. The sections of the inner cusps are nearly round, while those of the externals are cres- centic. This is due to the fact that they send out descending ridges to the inner side, one anteriorly, the other posteriorly. There is a small median posterior tubercle, rather better marked than in Jff. paulus. A low ledge connects the anterior cusps anteriorly, but there are no other cingula. The last inferior molar is narrowed and produced posteriorly, and the edge of the heel is elevated. Enamel entirely smooth. The anterior border of the masseteric fossa is distinct to about the middle of the depth of the ramus, where it disappears. Measurements. M. Length of premolars 0175 Diameters of M.ii^^°*«'^''I'°^*«"''' 0055 c transverse 0042 Diameters of M-iii^^^t^^P"^**™' 0062 I transverse 0045 Depth of ramus at M. ii 0115- 236 WASATCH FAUNA. I formerly referred the specimens of this species to the Phenacodus zitni- ensis, which is found in the Puerco horizon, but from which it is clearly- distinct. It is dedicated to Major J. W. Powell, director of the United States Geological Survey. From the Wasatch epoch of the Big Horn River, Wyoming, J. L. Wortman. Hyopsodus lemoinianus Cope. Paleontological BuUetin, No. 34, p. 148, 1882; Proceed. Amer. PhUos. Soc, 1881, p. 148 (1882). Plato XXIVe, figs. 8-9. This Mesodont is distinguished from the known species of the genus by its superior size, and the fully developed heel of the inferior third molar. The anterior inner cusps of the inferior molars are simple, though robust, and the same teeth have a weak external and no internal cingulum. The cusps are elevated, and are not strictly opposite, the external one being a little in advance of the corresponding internal one. The posterior external cusp is connected by a low ridge with the two internal cusps, respectively. On the first and second true molars there is a well-marked posterior median cusp. The fourth premolar is a robust tooth, with a short, wide heel, and a mere rudiment of an anterior basal tubercle. The heel has a principal submedian keel and small marginal cusp. There is another and rudimental lobe on the posterior border. The third premolar has neither internal nor anterior tubercle. Its heel is short and wide, and has a low angular median marginal lobe. Enamel smooth. Measurements. No. 1. M. Length of third and fourth premolars 0088 Diameters fourth Eremolar)''n""^P"'"«"0'^ 0045 C trausverse OOJO Diameters second true molar? ""teropoBterior 0050 '{' transverse 0O40 Depth ramus at Pm. iv 0030 No. 2. M. Length of M. iii 0056 Depth ramus at M. iii 0090 Mr. Wortman found in the bad lands of the Big Horn, Northern Wyoming, nine more or less fragmentary mandibles of this species. It is MESODONTA. 237 dedicated to Di*. Victor Lemoine, of Reims, France, well known for his many important discoveries in the lower Eocene formation, and his inves- tigations in various departments of zoology. Hyopsodus paulus Leidy. Proc. Acad. Phila., 1870, p. 110; 18T2, 20. Report U. S. Geol. Surv. Terrs., I., p. 75. Plate V, figs. 1-9 and 18-22. This species is abundant in the Bridger, Washakie, and Wind River Basins, and I have thirty-eight more or less broken mandibular rami from the Big Horn. With all these jaws there is not a single skull or skeleton. I am therefore unable to add anything to Dr. Leidy's description. Hyopsodus vicaeius Cope. Microsyops vicarius Cope. On some Eocene Mammals obtained by Hayden's Geol. Svirv. of 1872, p. 1, March 8, 1673. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 609. H. mmmcuUs Leidy. Report U. S. Geol. Surv. Terrs., I, 1873. Plate XXIV, figs. 20-21 ; XXVa, fig. 7. Founded on portions of the mandibular rami of two individuals from the bad lands of Cottonwood Creek, Wyoming. These represent an animal considerably smaller than the Hyopsodus paulus. The most complete speci- men was obtained from the Wind River region of Wyoming. It includes the dentition of both jaws, excepting the superior canine. The three superior incisors are of equal size and have angular spatu- late crowns in contact with each other. The external cusps of the pre- molars are simple. All the superior molars have a weak anterior basal cingulum. The last true molar is but little smaller than the others, and only differs in form in the rather more oblique external border. The infe- rior incisors are closely packed together. The root of the ^canine is not larger than that of the I. iii or Pm. i. The premolars follow the canine and each other without diastemata. The crown of the third premolar is rather obtuse, and has no anterior nor internal tubercle, but has a rather wide heel. The anterior edge of the fourth premolar is curved round abruptly so as to embrace the base of the inner cusp, and does not support an anterior cusp. Heel wide, with a submedian and a lateral keel. The 538 PUERCO FAUNA cusps of the true molars are alternate, and the internal intermediate of the last molar is near the lifth lobe or heel of the same. The symphysis of the mandible is not coossified, in contrast to the con- dition in Tomitherium. There are three mental foramina, one below the second and one below the anterior part of the fourth premolars. Measttrements. M. Length of superior dental series 0262 Length of superior incisors 0060 Length of superior true molars 0100 Diameters M. jj ^ anteroposterior 0036 ( transverse 0050 Length of inferior incisors, oblique on bases 0030 Length of inferior true molars 0110 Diameter of root of inferior canine 0020 Diameters Pm. iv | •■'°«"<'P««^rior 0027 < transverse 0024 Diameters M. ;; ^ anteroposterior 0039 ( transverse 0030 Diameters M.iii^ ="'*"«?"*"•■"'"• '^^^ ( t ransverse 0030 Eleven mandibular i-ami were procured from the Big Horn Basin, and a smaller number from the Wind River. Among the former, a few specimens are intermediate between this species and the last in dimensions, the inferior true molars measuring M. .0120 and .0125 in length. Hygpsodus acolytus Cope. Proceed. Araer. Philos. Soc, 1882, p. 462. Paleontological Bulletin No. 35 (Nov. 11, 1882). Plate XXIlId, figs. 5-6. This, the least species of the genus, is also the oldest, being derived from the Puerco horizon. Parts of the two individuals furnish the charac- ters of the inferior and superior true molars, and the fourth superior pre- molars. The species differ from those hitherto described in other charactei^s than the minute size. One of these is the absence of posterior interior cusp, the heels of the first and second true inferior molars being l)ounded b}- a ridge only at this point, as in most of the species of Pclycodus. The last inferior molar is not smaller than the second, nor longer. The anterior cusps of all the molars are robust, so that on the first and second true molars they are separated by a shallow notch only. There is a rudiment of the anterior inner cusp on the first true molar, but more o\\ tlie .second PEOSIMI^. 239 and third. The posterior external is obtuse and has a triangular section on all the molars. A crest is continued from the heel of the third molar on the inner side of the crown half way to the anterior inner cusp. Measurements. M. LeDgth of the inferior true molars 0100 Diameters M. n ^ anteroposterior 0038 c transverse 0034 Diameters M.iii^^°*''^°P°^*''™'" 0038 I transverse 0028 Depth of ramus at M. ii The Microsyops spierianus differs from this species in its smaller size (true molars .008) and in the presence of posterior, internal cusps of the true molars. The Hyopsodus acolytus was found by Mr. D. Baldwin, in Northwestern New Mexico. PROSIMI^. The suborder may be differentiated from the Mesodonta by the posses- sion of an opposable hallux of the posterior foot. This character is, how- ever, not yet demonstrated in the genera of the American Eocene, which I provisionally give to it, nor is the absence of the character known to belong to any of the genera of Mesodonta excepting Pelycodus. It is, iiowever, very probable that the other genera referi-ed to the Mesodonta agree with Pelycodus. It is also possible that some of the genera here referred to the Prosimiag agree with Pelycodus. In the uncertainty which exists as to the reference of the genus Cyno- dontomys and its immediate allies, I compare the genera of the Eocene lemu- roids as follows. I premise by observing that the genus Chiromys clearly represents a primary division of the Bunotheria, which occupies a position between the Prosimiae and the Tillodonta. The rodent-like incisors with permanent pulps are those of the Tillodonta, but the opposable hallux of the posterior foot is not found as yet in that suborder. The suborder has been named by Gill* the superfamily Daubentonioidea. •Arrangement of the families of Mammals, 1872, p. 54. 240 ' PUERCO FAUN^. We can distinguisli three families among our Eocene forms of lemu- roids, in the dental characters, as follows: Inferior premolars, four Adapida. Inferior premolars, three Mixodectidce. Premolars, two, with internal lobes in the upper jaw Anaptomorphidte. The genera of the Adapidce have already been considered (p. 215).* I therefore compare the genera of the two remaining families. MiXODECTIDiE. a. Last premolar without inner tubercle. A very large incisor; canine smaller; first premolar, only one-rooted Mixodectes. aa. Last premolar with internal tubercle. A very large t canine; first premolar only one-rooted Microsyops. A very large t canine; first and second premolars each one-rooted Cyodontomys. Anaptomorphid^. Inferior incisors two; canine small ; premolars two-rooted Anaptomorphua. Inferior premolars one-rooted Necrolemur. \^\ The correct nomenclature of the large tooth in the front of the mandi- \A i ble of the genera of Mixodectidce is not yet ascertained. It may be a canine or an incisor. I will also remark that in the genus Necrolemur of Filhol the characters of the superior premolars are not yet completely known. MIXODECTES Cope. Proceed. Amer. Philos. Soc.,1883, i). 447. Char. Gen. — The position of this genus is uncertain, but may be near to Cynodontomys Cope, which I have provisionally placed among the Pro- simian t It is known from mandibles, which have presumably the following dental formula : I. 0; C. 1; Pm. 4; M. 3. An uncertainty exists as to the proper names of the anterior teeth, which cannot be decided until the dis- • From that synopsis must be omitted the genera now placed in other families, Microtijopi ond AnaptomorphuK, anA Pan/o/cj^f* (Artiodactyla). Omomyt must be placed in the section with four pre- molars, in tlin place of Pantolestee. tPaU'ontologicul HuUotin, No. 34, p. 151. PKOSIMUB, 241 covery of the superior series. For instance, the formula may be: I. 1; C. . 1 ; Pm. 3. The supposed incisor is a large tooth, issuing from the ramus at the symphysis like a rodent incisor, and has an oval section, with long diameter parallel to the symphysis. The crown is lost from all the specimens. The second tooth is similar in form to the first, but is much smaller. It is situated posterior and external to the first. The next tooth is still smaller, and is one- rooted. The third and fourth premolars have simple conic crowns, and more or less developed heels without cusps. The true molars are in general like those of Felycodus ; i. e., with an anterior smaller, and a posterior, triangle or V. The supplementary anterior inner cusp is quite small, while the principal anterior inner is elevated. The posterior inner is much more elevated than in the species of Pelycodtis. Last inferior molar with a fifth lobe. This genus cannot be referred to its place without additional material, but the parts discovered indicate it to be between Felycodus and Cynodoh- tomys, either in the Mesodonta or the Prosimice. I may here remark that in defining the latter genus I was in doubt as to the number of the inferior premolars. The discovery of the present genus renders it probable that it has three such teeth, and that the anterior two are each one-rooted. MiXODECTES PUNGENS Cope. Proceed. Ainer. Philos. Soc, 1883, p. 447. Plate XXIVf ; fig. 1. The mandible of the Mixodectes pungens is about the size of that of the mink. Its inferior outline is sti-aight to below the second premolar, whence it rises upwards and forwai'ds like that of a rodent. The anterior masse- teric ridge is very prominent, but terminates below the middle of the ramus Inferior masseteric ridge much less pronounced. The inferior part of the ramus is robust below the base of the coronoid process, but there is no in- dication of recurvature of the edge. Mental foramina two ; one below the front of the first true molar, and one below the second premolar. The oval base of the canine is not flattened on either side; that of the second tooth is flattened on the inner side. There is a great difference be- tween the sizes of the last three premolars. The fourth is twice as large 16 c 242 PUERCO FAUNA. as the third, and the second, judging from the space and the size of its al- veohis, was much smaller than the third, and the crown was probably a simple acute cone. The crown of the third is of that form, with the addi- tion of a short heel. The long axis of the base of the crown is diagonal to that of the jaw. The fourth premolar has a relatively larger heel than the third, but it is shorter than the diameter of the base of the cusp. Its pos- terior edge is elevated. The cusps of the anterior pair of the true molars are elevated, but the interior is the most so. The supplementary one is not exactly in the line of the interior border of the crown. Each of the inner cusps are connected with the base of the external by a ndge, which together form a V. The posterior base is nearly surrounded by a raised edge, which rises into cusps at the posterior lateral angles. Of these the internal is the more prominent. The edge connecting these cusps is slightly convex backwards, and evidently bears a part in mastication. The lateral borders of the last molar are somewhat expanded, and the fifth lobe is very sliort. No cingula on any of the teeth. Measurements. M. Ivfiigth of dental sorieB from "canine" exclusive 0265 LeugtU of true molar series 0140 T^- » „ 11 • II < loiiKltudinal 0040 Diameters "canine" { ^ c trausverse 0030 Long diameter of base of "Piii. i" ^ 0028 Long diameter of base of Pm. ii 0017 0055 roposterior 0050 transverse 0038 anteroposterior 0050 Length of crown of M. iii 0060 Depth of raII^ls at Pm. iii 0090 Depth of ramus at M. iii 0100 From the Puerco epoch of New Mexico; D. Baldwin. MiXODECTES CRASSIUSCULUS Cope. Proceed. Amer. Philos. See, 1883, p. 417. Plato XXIVf ; fig. 2. This mammal is represented by fragments of three mandibles from differ- ent individuals, one less and the other more worn by mastication. The species differs from the last in its greater size and in the relatively greater T\- . T> • ^ vertical Diameters Pm. jv ! I anteropi Diameters M. ii < PEOSiMi^. 243 length of the last inferior molar. The length of the posterior four molars of the M. pungens equals that of the three true molars of the M. crassius- culm; and the last true molar of the latter is half as long again as the pen- ultimate, while in M. pungens it exceeds it but little. The best preserved true molar is the second. Its most elevated cusps are the anterior and posterior inner, of which the anterior is subconic and more elevated. The anterior external cusp is crescentic in section, and sends crests to the supplementary, anterior inner, and the posterior anterior inner, both of which descend inwards. The posterior crest reaches the pos- terior base of the anterior inner cusp. The posterior external cusp is an elevated angle, sending crests forwards and backwards. The former reaches the base of the anterior external cusp (not reaching the inner), while the latter passes round the posterior edge of the crown. As in M. pungens, it is convex posteriorly, and rises to the pos- terior internal cusp. In both species its appearance indicates that it per- forms an important masticatory function in connection with the superior molar. No cingula. Measurements. u. Leugtli of bases of M. ii and iii (No. 2) 0125 Length of base of M. iii (No. 2) 0070 Diameters crown M. ii (No. 1) ^ '*°t''''''P°«'«"°'' ^^ ( transverse 0050 Depth of ramus at M. ii (No. I) 0100 From the Puerco Eocene of New Mexico; D. Baldwin discoverer. CYNODONTOMYS Cope. Paleontological Bulletin, No. 34, p. 151, Feb., 1882. Proceed. Amer. Philos. Soc, 1881, p. 151 (1882). The characters of this genus are derived from mandibular rami. Dental formula I. "? 0; C. 1 ; Pm. 3; M. 3. The premolars are counted as three, on the supposition that the anterior two are one-rooted ; should it prove to be singleand two-rooted, then the number will be two. The canines (orincisorsi) are very large and close to the symphysis, so that there do not appear to have been any other incisors. The true molars have the frequently occurring three tubercles infront and a heel behind; but the arrangement is peculiar in that the three tubercles are but little more elevated than the borders of the heel, and 244 WASATCH FAUNA. occupy a small part of the crown. The last molar is lost from both jaws, but the space for it is about as lar^^e as that occupied by the penultimate. The fourth premolar has but two anterior cusps, and these are more elevated than those of the true molars, and the heel is narrower. The, mandibular rami are not coossified. The dental characters of this genus resemble considerably those of Anaptomorphus and Necrolemur, but .the large size of the inferior canine or incisor tooth distinguishes it from both. The double anterior cusps of the fourth premolar equally distinguish it from them. Cynodontomys latidens Cope. Proceed. Araer. Philos. Soc, 1881, p. 151 (1882). Plale XXIVe, fig_2. This species is known from a pair of mandibular rami which are bound together by matrix. Th^ infei-ior true molars are subquadrate in horizontal outline, some- what narrowed anteriorly. The concave heel is the larger part of the crown; it is only elevated into a low cusp at the posterior external angle. The anterior cusps are conic, and are in contact at the base. The external and posterior internal are of about the same size; the anterior inner is smaller and does not project so far inwards as the posterior. The fourth premolar has the posterior border of its heel serrate. The anterior cusps are elevated and moderately acute; the internal is a little less elevated than the external, and is separated from it by a deep notch. The alveoli for the anterior premolar are not so close together as to render it probable that they belong to but one tooth. They are placed somewhat obliquely to the long axis of the jaw. There is no diastema. The section of the base of the crown of the canine is a regular oval, the long diameter coinciding with the vertical diameter of the ramus The ramus is rather slender, but is shortened anteriorly. The bound- aries of the masseteric fossa are well marked, the anterior ridge descending to below the n)iddle line of the ramus. The mental foramen is large, and is situated below the contact of the two premolars. Tlie inferior edge of the ramus is rather thick. PEOSIML^, 245 Measurements. M. Length of deutal series, including canine 0240 Leogtli of premolars 0062 Length of molars 0114 Long diameter base canine 0036 Diameters Pm. iv ^ ''°t«''°P°«*«"'"- ^'^ i transverse 0026 Diameters Pm. M. ii < ''^f«''°P°^*<^""'' 0042 ( transverse 0038 Depth of ramus at Pm. i 0060 Depth of ramus at M. iii 0068 Big Horn bad lands, Northern Wyoming; J. L. Wortman. ANAPTOMORPHUS Cope. Proceed. Auier. Philos. Soc, 1872, p. 554. Paleontological Bulletin, No. 8, p. 1. Oct. 12, 1872. llTaahakiits Leidy. Report of the U. S. Geol. Surv. Terrs, i, p. 123, 1873. The genus Anaptomorphus was characterized by me in 1872, from a mandibular ramus which exhibited the alveoli of all the teeth, three of them occupied by the teeth, viz, the Pm. iv, and the M. i and M. ii. From the specimen the inferior dental formula was ascertained to be I. 2, C 1, Pm. 2, M. 3. The Big Horn collection contains a nearly entire cranium of what is probably a species of the same genus. From it the superior dentition, exclusive of the incisors, is determined to be C 1, Pm. 2, M. 3. The pre- maxillary bones are mostly broken off, but a jjart of the alveolus of the external incisor of one side remains. The indications are that the external incisor was a small tooth, not exceeding the canine in size, and it was situated close to the latter. The canine is also small, and its simple crown is not more prominent than those of the premolars. The latter are separated from it by a very short dias- tema. The long diameter of their crowns is transverse to the long axis of the jaw; and each one consists of a larger external and smaller internal cusp. The true molars are also wider than long, and support two exter- nal and onlj^ one internal cusps. This genus was founded on the left ramus mandibuli of a single species. The posterior portion is broken away, and the teeth remaining- perfect are the-Pm. 4 and M. 1 and 2. The ramus, though small, is stout, and deeper 246 WASATCH FAUNA. at the symphysis than at the hist iiKtlar. What appears to be the dental foramen is nearly opi>osite the bases of the crowns of the molars. Dentition of the ramus mandibuli, In. 2, C. 1, Pm. 2, M. 3; total 16. There is no interruption in the series near the canine, and the symphysis, though massive, is not coossified. The third (first) premolar is two-rooted. Further details are, tlie last mohir is three-lobed and elongated behind. The composition of the crowns of the preceding molars consists of four opposed lobes, which are very stout, and connected transversely by a thin ridge behind, and are in close contact in front. The premolar tooth, which is best preserved, is a perfect second, which, while having two roots, pos- sesses a crown which stands almost entirely on the anterior, presenting a curved sectorial crest forwards and upwards. • The orbits are large and are entirely inclosed behind. The frontal bone does not send inwards to the alisphenoid a lamina to separate the orbit from the temporal fossa, as is seen in Tarsius. There is no sagittal crest, but the temporal ridges are distinct. The occipital region protrudes beyond the foramen magnum, or at least beyond the paroccipital process, wliich is preserved, the condyles being lost. The otic bulla is large, extending anteriorly to the glenoid cavity. The pterygoid fossa is large, the external pterygoid ala being well developed, and extending well upon the e.xtero- anterior side of the bulla, as in Tarsius. As in that genus, the foramen ovale is .situated on the external side of the bulla, just above the base of the extenial pterygoid ala. Tho carotid foramen, as I suppose it to be, is situated at the apex of tiie bulla. The lachrymal foramen is situated ante- rior to and outside of the orbit, as in Lemuridce generally. The cast of the anterior part of the left cerebral hemisphere is exposed. This projects as far anteriorly as the middle of the orbits, leaving but little room for the olfactory lobes. The relations of the latter, as well as of other parts of the brain, will be examined at a future time. The part exposed does not display fissures, and gentle undulations represent convolutions. The characters of this genus now known warrant us in thinking it one of the most interesting of Eocene Mammalia. Two special characters con- firm the reference to tho Lemuruhr which its ])hvsiognomv suggests. These PROSEVILE. 247 are the external position of the lachrymal foramen and the unossified sym- physis mandibuli. Among Lemuridce its dental formula agrees only with the Indrisince, which have, like AnaptomorpJms, two premolars in each jaw. But no known Lemuridce possess interior lobes and cusps of all the premo- lars, so that in this respect, as in the number of its teeth, this genus resem- bles the higher monkeys, the Shniidce and Hominidce* more than any exist- ing number of the family. Of these two groups the resemblance is to the Hominidce in the small size of the canine teeth. It has, however, a number of resemblances to Tarsius, which is perhaps its nearest ally among the lemurs, although that genus has three premolars. One of these points is the anterior extension of the otic bullae, which is extensively overrun by the external pterygoid ala. A consequence of this arrangement is the external position of the foramen ovale, just as is seen in Tarsius. Another point is the probably inferior position of the foramen ovale. Though this part is broken away in the cranium of Anaptomorphus homuncidus, the pai-- occipital process is preserved, and has the position seen in Tarsius, as dis- tinguished from the Indrisince, Lemuridce, Galagince, etc. In this it also resembles the true Quadrumana. When we remember that the lower Quadrumana, the Hapalidce, and the Cebidce have three premolar teeth, the resemblance to the higher members of that order is more evident. The brain and its hemispheres are not at aU smaller than those of the Tarsius, or of the typical lemurs of the present period. This is important in view of the very small brains of the flesh- eating and angulate Mammalia of the Eocene period so far as yet known. In conclusion, there is no doubt but that the genus Anaptomorphus is the most simian lemur yet discovered, and probably represents the family from which the true monkeys and men were derived. Its discovery is an im- "portant addition to our knowledge of the phylogeny of man. I find on examination of the specimen on which Dr. Leidy based his WashaMus insignis, which he kindly permitted me to make, that the corre- sponding parts preserved, the last two inferior molars, do not differ from In an early description of Anaptomorphus, Proc. Amer. Philos. Soc, 1873, the types make me say "this genus » » • might be referred decidedly to the Lemuridw, 'weie it not for the unossified symphysis." It is scarcely necessary to state that Simiidniiltiniato molars 012.'> Length of suixTior molar wrics 001)5 Length of superior true niolars 0060 CREODONTA. 251 Diameter8ofcrownofcanine^^t«™P°''*«"<'' ^^^ i vertical 0018 Diameters crown of Pm. hi 5 anteropoeterior 0020 ( transverse 0026 Diameters crown of Pm. iv 5 anteroposterior 0020 ( transverse 0035 Diameters M. ii 5 ''"t'="''''"'«terior 0032 ' transverse 0040 Diameters M.iii^^"t«''°I"*»*''"°'^ ^^^ ( transverse 0028 Diameters of orbit ,<™'*'™P°«*®""'" "l^" < vertical (f depressed) 0078 Interorbital width (least) 0050 The AnaptomorpJms homunculus was nocturnal in its habits, and its food was like that of the smaller lemurs of Madagascar and the Malaysian islands. Its size is a little less than that of the Tarsius spectrum. The typical specimen was found by Mr. J. L. Wortman in a calcareous nodule in the Wasatch formation of the Big Horn Basin, Wyoming Territoiy. As compared with the A. cemulus it is smaller in the dimensions of its teeth. CREODONTA. Cope, Proceed. Acad. Phila., Dec. 1875. Report Capt. \Vheeler Expl. Surv. W. of 100th Mer., iv, pt. ii, pp. 72 and 87. Unguiculate (?) placental Mammalia, with separate scaphoid and lunar bones; narrow cerebral hemispheres, and very large and exposed olfactory lobes; and the ankle-joint generally not trochlear. The above definition was derived from the flesh-eaters of the Suesso- nian formation of New Mexico and France. The characters of the brain have been demonstrated in three genera: in Arctocyon by Gervais; Oxycena by Cope, and Stypolophus by Filhol. The peculiar ankle-joint was shown to be present in four genera, Amblydonus, Oxycena, Stypolophus, Didymictis, and Heteroborus. The uniform absence of the characteristic cai'pal bone of the Carnivora, the scapho-lunar, gave ground for inferring its division into its primitive pieces in the same genera; and the view was supported by the existence of this division in the Bridger genus Mesonyx. How far these characters are common to the flesh-eaters of the Bridger formation is yet uncertain. The genus Mesonyx differs widely in its ankle- joint, but its dentition is so near that of Amhlyctonus that they probably 252 EOCENE FAITN.-E. belong to the same greater division. In the same way Miaci^ must probably follow Didymictis. For the present, then, I refer the genera of the Bridger formation known to me, tu thu Creodonta. The affinities of the Creodonta may be estimated as follows : The glenoid cavity of the squamosal bone is transverse, and well defined anteriorly and posteriorly, as in the Carnivora. In all the genera of the Suessonian or Wasatch, the ilium has a well-marked external anterior ridge, which continues from the acetabulum to the crest, distinct from the internal anterior ridge. The ilium has therefore an angulate or convex external face, as in Insedivora and Marsupialia, and does not" display the usual expansion in a single plane of most of the placentals. In all the genera there is a strong tuberosity in the position of the anterior inferior spine, which is wanting in the Mammalia, excepting certain Imedivora and Prosimice, although it marks the position of the origin of the rectus femoris muscle in all types. In Amhlydonus, Didymictis, Protopsalis, and three undetermined forms, the femur supports a third trochanter. In some species, where the cuboid bones are preserved, it is evident that the distal end of the astragalus articulated with this as well as with the navicular bone, although the facet of the astragalus is single and continuous. As the extensive transverse distal astragalar face is characteristic of all the species where it is preserved, the contact of the cuboid and astragalus is probably common to all of this division. There is no elongation of the navicular ; it is, on the contrary, very short, since the astragalus projects beyond the calcaneum (in the genera where they have been observed). The cuboid is, on this account, rather elongate, but not remarkably so. There were five toes in the hind feet of some of the species. The ungues in some of the genera are compressed and acute. In the genus Mesonyx, from the Bridger, I found one of the claws to be broad and flat, so as to be subun- gulate I found an ungual phalange in New Mexico, probably belonging to a species of this group, which |)resented a simihu-, though less expanded, form. I have every reason t'nr believing that there were five toes on the hind foot f)f Stypolophus hians and a second species. CREODJNTA. 253 The characters now adduced lead to the following conclusions as to the systematic position of these animals. The small size of the cerebral hemispheres and the rare occurrence of convolutions, refer this group to the Lissencephalous or Lyencephalous Mammalia. The characters presented by our crania are borne out by those exhibited by the Ardocyon j)rimcevus, De Blainv., from the Lower Eocene or Suessonian beds of France. Professor Gervais* has discovered that the olfactory lobes are large, and project far beyond the hemispheres, while not onl}' the cerebellum but also probably the corpora quadrigemina were exposed behind. We are therefore restricted, early in the inquiry, to com- parisons with a few orders. These are the Insedivora, Marsupialia, and some of the Prosimioi, which have small brains. Other characters, however, exist, Avhich add to the reasons for separating them from the Carnivora. There is nothing in the dentition inconsistent with the orders Carnivora,. Insedivora, and Marsupialia. It resembles that of some Viverridce of the first, MytJiomys of the second, and the Sarcophaga oi the third. Neverthe- less, in the often limited number of incisor teeth, it approaches most nearly to the Insedivora. The transverse glenoid cavity is that of the three orders named, and distinguishes the group from the Rodentia. So far as known, the coossification of the scaphoid and lunar bones, the distinguishing character of the Carnivora, i.s wanting. The angulate shape of the ilium is that of Insedivora and Marsupialia. It is less apparent in Chiroviys, and is not characteristic of the higher Mammalia. The large anterior inferior tuberosity is especially a character of the Lemurs, other than Nydicebinoi (Mivart),t the Chiromys, and of certain Insedivora, especiall}^ Solenodon. It is figured by Mivart in Indris and Loris, by Owen in Chiromys,X and by Peters in Solenodon.§ It is absent in Carnivora, the true Quadrumana, Marsupialia, and many Insedivora. Allman || does not represent it in Mythomys. The third trochanter of the femur is wanting in * Nouvelles Archives du Museum, 1870, p. 150. tin a memoir in the Philosophical Trausactions, vi, p. 421. { Proceedings of the Zoological Society of London, v, pi. xxi. J Abhandlungeu der kiiuiglichen Academie der Wissenschaften, 1863, pi. 3, Ueber Solenodon cubanus. II Transactions of the Zoological Society of London, vi, pi. -2, On (Poiamogale) Mythomys velox. 254 EOCENE FAU>^E. the Gyrencephalous oidei's generally, characterizing only the Perissodactyla. Among Lisaencephalous orders, it is very common in the Edentata, and still more usual in the Insectivora It does not occur among Marsupials. But in the Prosimice, there is often a third trochanter (Mivart, loc. cit.; e. g., Lemur, Galago). In Talpa and some other Insectivora, and also in Chiromys, it is situated high up, nearly opposite the little trochanter. The peculiar character of the ankle-joint already mentioned is not certainly characteristic of all the genera of this division. In Mesonyx it is aa perfect a tongue and groove as in the most specialized of existing Carnivora. In the Creodonta of the Wasatch it is on the contrary flat, and resembles moi'e than any other existing type the ankle-joint of the otter. It probably indicates aquatic habits of the species possessing it. The comparison of this group brings out principally aflSnities to the Insectivora and Prosimice Besides the differences from the Marsupialia, already pointed out, in the genera Oxycetia and Didymictis, the posterior part of the inferior border of the mandibular ramus is not inflected, as in Marsu- pialia; in Stypolophtis (viverrinus) the lachi'ymal canal is within the orbit, and not exterior to it. The frequently reduced number of incisors in the lower jaw and the normal number above, are a further ground of distinc- tion from the Carnivorous Marsupialia. Comparison with the Prosimice shows that the difi'erences consist in the sectorial character of some molar teeth, and large development of the canines, in the Eocene forms ; in the short tarsal bones, and peculiar tibio-tarsal articulation; with convex external face of the ilium. This ensemble of characters can hardly be regarded as ordinal ; and there only remains, to give character to such a distinction, the difference in the size and form of the cerebral hemispheres. This character, in some of the smaller living Lemuridce, is not strongly marked, and in them the approximation to the Lissencephalous Manmials is at its closest. The differences from the Insectivora are less numerous. The only trenchant distinctive character upon which I can seize, in comparison with Myfhomys and Solenodon, is the peculiar tibio-tarsal articulation. On this account, and because of the rather more marked camassial characters of the molar teeth, I have proposed to place the genera Aniblyctonus, Oxycetia, CKEODONTA. 255 Stypolophus, and Didymictis in a suborder of Insectivora, under the name of Creodonta* They stand also in relationship to the Lemurs, and more remotely to the Carnivora. History. MM. Laurillard, Pomel, and others have referred the Kuro- pean Creodonta to the 3Iarsupialia, on account of the great similarity of the dentition. MM. De Blainville and Gervais have, on the other hand, regarded them as placental, a view which I liave assigned reasonsf for believing to be the correct one. M. Filhol has recently shown that the replacement of the dentition in Hycenodon, which has some affinities with the Creodonta, is quite as in true placental Carnivora. Professor Gaudry has expressed the opinion that the Creodonta are the descendants of the Marsupialia.X I have proposed another view.§ If we suppose that the Creodonta are the descendants of the Marsu- pialia, we must suppose that the Insectivora, to which they are related, are also the descendants of the Marsupialia, and this is on various grounds not very probable. The lower forms of unguiculate Mammalia with small cerebral hemispheres are very much alike in important characters, and to these I have given the name of Bunotheria. I suspect that this group is as old as the Marsupialia, and may even have given origin to it. That it devel- oped contemporaneously with it in various parts of the world, is evident. Bestoration. The Wasatch beds of New Mexico have yielded remains of more than a dozen species, which ranged from the size of a weasel to that of a jaguar. The Bridger beds of Wyoming probably contain as many species, which range from small size to the dimensions of a bear. In general appearance the Creodonta differed from the Carnivora, in many of the species at least, in the small relative size of the limbs as com- pared with that of the head, and in some instances as compai-ed with the size of the hind feet. The feet are probably plantigrade, and the posterior ones capable of some degree of horizontal rotation. The probable large size of the rectus femoris muscle indicates unusual power of extension of the hind limb. This may indicate natatory habits, a supposition further * On the Supposed Carnivora of the Eocene of the Rocky Mountains, by E. D. Cope. 8vo. Phila- delphia, Dec. 22, 1875. t Proceedings Academy Phila.,1875. Paleontological Bulletin, No. 20, Dec, 1875. { Enchainements du Monde Animal, 1878, p. 24. } Proceedings American Philos. Soc. 1880, p. 76. 256 EOCENE FAUN^. justified by the flat tibio-tarsal articulation. They were furnished with a long and large tail. Probably some of the species resembled in propor- tions the Mystomys and Solenodon, now existing in Africa and the West Indies, but they mostly attained a much larger size. The habits of many of them were probably aquatic. Classification. To the Creodonta I have refeired,* on the information which we possess, the genus Arctocyon of Blainville. Professor Gervais has discovered that it possessed the very small cerebral hemispheres charac- teristic of the Creodonta The olfactory lobes are large, and project far beyond the hemispheres, while not only the cerebellum, but probably the corpora quadrigemina, were exposed behind. The tarsal articulation and the posterior part of the mandibular bones are unknown; hence this refer- ence is not certain. Professor Gervaisf regai-ds it, after Laiu-illard,t as a marsupial, and establishes an especial family of the order for its reception. It is, however, more probable that its affinities are with the contemporary genera of flesh-eaters, Palceonyctis Blv., and Pterodon Blv., genera w'hich have near allies among the American forms. Palceonyctis was the contem- porary of the Coryphodons in the Suessonian period of Western Europe, and presents a strong resemblance to Amhlyctonus in its mandible, the only part of the skeleton known. The posterior part of the ramus is not inflected according to Gervais, and he therefore does not refer it to the Marsupial ia.§ The neai-est European representative of Oxyoena is Pterodon, in which the form of the mandible also forbids a reference to the Marsiipialia, as Gervais has remarked. Both genera are doubtless members of the suborder of Creodonta. The genus Hycenodon, on the other hand, is not referable to the same group, for I find in a si)ecimen of the H. requieni fi'om Dcsbruges, preserved in the Museum of the Jardin des Plantes, that the scaphoid and lunar bones are coossified. Moreover the figure given by Professor Gervais, || representing the brain of the originally-described type, H. Icptorhynchus of the Miocene period, displays characters of the true Carnivora. The anterior part of the cranial cavity of the specimen molded, is broken away. ' Report Capt. G. M. Wheelc-r'B Expl. Sun-. W. 100 Mcr., 1877, iv, pi. ii, p. 38. tNouv. archives du museum, 1870,p. 150. (Diet. aniv. d'hist. naturello, ix, p. 400. f Nouv. archives du mnaeum, 1870, ICil. I Loo. cit., pi. vi, fig. &. CREODONTA. 257 Fig. 7. Fig. 8. It is possible that the genus Diacodon Cope belongs here also; its species resemble some Marsupialia in the inferior dentition, and are of small size. The genus Mesonyx* which I discovered in the Bridger beds of Wyoming, has the trochlear face of its astragalus completely grooved above as in the true Carnivora, and its distal end presents two dis- tinct facets, one for the cuboid and the other for the b navicular bones. It represents on this account a peculiar family, the Mesonychidce. There are various degrees of development of the sectorial structure of the molars in this suborder. In ' some of them, as Didymictis, only one of the inferior molars presents this structure ; in othei's two, and In one type, the last superior molar Fig. 7. Distal extremity of tibia of Amhhjclonus xinimus jj^ otllCrS three, Cope. Fig. y. Distal cx- treniity of tibia of or^ffna IS lougitudinal ; in others, it is transverse. In Arc- thirds natural size. From Report Expl. and Surv. W. of lOOth Mer., G. M.Wheeler, tocyon the superior true molars are tubercular. The glenoid cavity of the squamosal bone pre- ivj pt. ii. sents differences in the various genera of this sub- order. In Arctocyonidcc (fide De Blainville), Oxycenidce, and Mesonychidce it is bounded by a transverse crest anteriorly, as well as by the postglenoid Fig. 9. posteriorly, while in the Leptictidce it is plane 3 and open anteriorly. In * Amhlyctonidce. its con- 1 dition is unknown. In 2 existing Carnivora this chai-acter is not very constant as a family Fig. 9. Portions of maxillary and mandibular bones of Oxydiim Zii^iHa UeiinitlOn ; it IS DCSt Cope, one-half natural size; a, maxillary bone from below; b, last Azt^A *n t]iA VcJirl superior molar. From Report Expl. Surv. W. 100th Mer., G. M. Wheeler, vol. iv, pt. ii. and least marked in the Canidce. Nevertheless there is a group of genera allied to the OxycenidcB, which are very marsupial in character, which have been called the Leptic- * Annual Report U. S. Geol. Surv. Terrs., ltJ72, p. 550. 258 EOCENE FAUNA. ti(lremolar like true molars Uiacodun Cope. II. Fourth inferior premolar ditlerent from true molars in a simpler constitution. a. Inferior true molars not (or not all) tubercular sectorial. Last inferior molar tubercular; cusi)s of other true molars well develoiied; three pre- molars above and below Deltatheriiim Cope. Inferior true molars alike, with anterior inner cnsps little developed; three premo- lars (?) TriisodoH Cope. aa. Inferior true molars all tubercular sectorial. Inferior true molars alike, with cusps well developed ; four compressed premolars below, three above Didelphodus Cope. Premolars four below, robust, conic Quercitherium Filh. Premolars four above and below, compressed ; the fourth superior with a conic cusp and heel externally Styolo2)hus Cope. Premolars four below, compressed; fourth superior with a simple blade externallj. Proviverra Riitim. MlACID^. Inferior tubercular molars two, premolars four Miacis Cope. Inferior tubercular molars one, premolars lour Bidymictis Cope. OXYJENIDiE. I. Inferior molars without internal tubeicles. Molars, ^ f ; three sectorials in the lower jaw Pterodon Blv. II. Inferior molars with internal cusjis. a. Posterior heel of one or more superior molars elongate and trenchant. Last inferior molar truly sectorial, without internal tubercle; second tubercular-sec- torial Protopxalis Cope. Molars, a 5; two last inferior molars tubercular sectorial Oxyana Cope. Amblyctonid^e. Fourth inferior premolar with a broad heel supporting tubercles; an anterior and no internal tubercles A7nblyctoiiii>i Cope. iJental formula below, 3, 1, 3, 3. Fourth inferior premolar with a cutting edge on the heel ; both internal and anterior tubercles Palaonyctis Blv. ^Iesonychid^. a. Inferior molars seven. Cones of inferior and superior molars simple. Mcsonyx Cope. Cones of last two inferior molars with lateral cusps Dixsacus Cope. an. Inferior molars f six. Internal lobes of penultimate superior molar v-sbaped Sarcothrausles Cope. ari'i. Inferior molars five. Inferior molars with strong anterior lobe. tPatrio/clis Leidy. CEEODONTA. 261 Of the preceding genera it may be remarked that the structure of the feet of Pterodon being unknown, it may be found hereafter to be necessary to remove it from the Oxyosnidce, although I do not anticipate that such a course will be necessary. Palceonydis is only known by the mandibular dentition, which is very near to that of Amhhjctomis. So also it is not certain, but only possible, that Patriofelis belongs to the Mesomjcliidre of the same horizon and locality. The horizontal and geographical distribution of the species of these twenty-seven genera is as follows: Arctocyon primoevas Blv Hyodectes gervaisi Lem Hcteroborus duelii Lem Mioclsenus turgidus Cope miuiraus Cope subtrigonus Cope ferox Cope baldwini Cope protogonioiides Cope . bncculentus Cope . . . . niandibularis Cope . . . Achienodon insolens Cope Qviercitheriuiu tenebrosum Filb . Diacodon celatiis Cope alticnspis Cope Ictops bicuspis Cope didelphoides Cope Peratherium comstockii Cope... Deltatherium fnndaniinis Cope . interruptus Cope . . . baldwini Cope Didelpbodus absarokoe Cope Stypolopbus viverriuus Cope . . . secundarius Cope . . ranUicuspis Cojte . . strenuus Cot)e minor Filh cavliisi Filh Lower Eocene. N.A. Eur. Middle Eocene. N.A. Eur. 262 EOCENE FAUNA. Stypolophns pnngens Cope brevicalcnratus Cope whitiiE Cope aculeatus Cope hiana Cope Proviverra typica Riitim Trilsodon qnivircnsis Cope , heilprinianns Cope lerisianas Cope conidens Cope Miacis parvivoruB Cope edax Leidy voras Leidy canavus Cope brevirostris Cope Didymictis altidens Cope protemis Cope leptomylus Cope dawkiusianiia Cope haydenianus Cope massotericus Cope curtidens Cope Pterodon dasynroides Blv biincisi VU8 Filh Protopsalis tigrinus Cope Oxyiena morsitans Cope Inpina Cope forcipata Cope Amblyctonns sinosus Cope sp. no. 2* Pala-onyctis gigantea Blv S.ircothranstes aiitiqims Cope Dissacns Davajoviiig Cope carnifex Cope Mesonys obtusidens Cope lanius Cope ossifragiis Cope Patriofelis nlta Leidy Lower Eocene. Middle Eocene. N.A. Enr. N.A. I Enr. • Etpresentcd by a mandible -n-ith teeth, from Mendon, osBooiated with the specimens of Palcro- nyctis in the Mus. Jiirdin dcs PlantcB. CEEODONTA. 263 Phylogeny. It is among the genera above enumerated that we are to look for the ancestors of the existing Carnivora, excepting, perhaps, the seals, and even these were probably contemporaries. The genera with developed inner cusps and tubercles of the molars, are probably modifications of the Leptictidce, which are also nearest to the Marsupialia. In those genera without developed internal tubercles of the molars, we may look for the ancestors of the Hycenodontido&, a family which early attained specialization at the expense of strength of structure, and did not survive the Lower Miocene period. Such genera may be found in the Mesonychidce as the later, and the Amhlyctonidce as the earlier types. In distinguishing between the ancestors of the Felidce and Canidce, we naturally seek to recognize in each an anticipation of the leading characters in the dentition which distinguish those families to-day. This consists, in the Felidce, in the successive abbreviation of the true molar series from behind, so that ultimately two molars are lost, and the remaining or anterior one becomes transverse ; also in the development of a preglenoid cross- ridge which embraces the mandibular condyle in front. On the other hand in the Canidce, firstly, the full number of true molars is retained in some genera, as AmpJiicyon, and only one is lost in Canis. Secondly, the tubercular character of the posterior molars in both jaws in the Canidce is distinguished from their sectorial character in Felidce. Estimated by these tests the Miacidce are clearly the forerunners of the Canidce, and the Oxyce- nidce, of the Felidce. In Miacis we have in fact a near approach to the den- tition of Canis, in the lower jaw; while in the same part of Didymictis, posterior abbreviation has commenced, reminding one of Viverra. In the Oxycenidce, one degree of posterior abbreviation is seen in Stypoloplms, where the last superior molar is narrowed and turned at right angles to the others. In Oxycena, the process had advanced a step, for there are but two superior true molars, and the last of these is driven in, transversely. The first true molar is functionally sectorial in this genus, while the last premolar is the true sectorial of the superior series in existing Carnivora. In the inferior series there are only two true molars in Oxycena, both primitive, or "tuber- cular-sectorial" in character. In existing Felidce the second is lost, while the first undergoes great changes in becoming a specialized sectorial. The 264 THE WASATCH AND BRIDGEK FAUN^. forms of the Felidce, which are nearest, are the Cryptoprocta, and the Proce- lurus of Filhol, but they only follow after a wide interval. I have else- where discussed the successive steps in the evolution of the sectorial itself* I have also pointed out f the successive shortening of the anterior part of the dental series in the Felidce and other groups of existing Carnivora, which came later in time. The following table will give an idea of these affinities, and the phylogeny to be derived from them : Felidw. Felidae. Oxycena. Oxvsenidse. CaDidse. Canidae. Miacidse. Hyaenodontidae. LeptictidiE. Meson vchidae. Amblvctoiiidse. Synonynn/. Professor Gaudry has united Stypohphus {Cynohyoenodon Filhol) with Proviverra. After an examination of casts of Riitimeyer's types preserved in the Museum of the Jardin des Plantes, I retain them as distinct for the reasons given above. Mr. Bose, in an interesting paper The dental characters of the species included in this genus, so far as they are known, are identical with those of Didelphys, and authors have generally regarded the name as a synonym of the latter. Species are numerous in the Upper Eocene of France and in the White River beds of the United States. I retain Aj-mard's name provisionally, until the number of superior incisor teeth of the species concerned is known. The Leptic- tidce that are known, do not have so many of these teeth as does Didelphys^ there being only two in LepUctis (fide Leidy) and three in Ictops {hicuspis) on each side. The genus Leptictis is quite near this one, as is also Ictops. The reduction of the anterior inferior cusp of the inferior molars, already seen in the latter, is carried nearly to extinction in Diacodon. Only one, a small species of this genus, has yet been found in the Eocene beds of North America. Pekatherium comstocki Cope. Plate XXV (I, fig. 15. Portions of the mandibles of two individuals of this species were found by Mr. Wortman in the bad lands of the Wind River, Wyoming. They indicate animals a little larger than the P. fugax Cope of the White River beds of Colorado, or about equal to the cave-rat {Neotoma floridana). The generic characters include most of those displayed by the denti- tion. The heels of the molars support an acute tubercle anterior to the posterior border, and their external angles are elevated and have a cres- centic section. The anterior internal cusp is not quite so elevated as the median internal cusp, but both are in the same longitudinal plane of the jaw. The posterior internal tubercle is as high as the anterior. The enamel is smooth, and there are no cingula. Measurements. M. Length of two inferior molars 0063 c (total 0037 Diameters of first true molars < ' ' J of heel 0019 ' transverse at heel 0017 Depth of ramus at first true molar 0048 Dedicated to Prof. Theodore D. Comstock, of Cornell University, New York, who explored the Wind River region as geologist of the expedition under Captain Jones, United States Engineers. 270 THE PUEECO FAUNA. TRIISODON Cope. American Naturalist, 1881, p. 667, August (July 27). Proceed. Amer. Philos. Soc, 1881, p. 485. The type of this genus is only known from portions of lower jaws; some of these include the entire dentition, with unimportant omissions. True molars alike, consisting of three anterior cusps and a heel. The cusps are relatively small and the heel large. Of the former the internal is mucli smaller than the external, and the anterior is rudimental, being merely a projection of the cingulum. The cutting edges of the large ex- ternal cusp are obtuse. The heel is basin-shaped, and its posterior border is divided into tubercles, of which the external is a large cusp. The fourth premolar has no anterior or posterior inner tubercles, so that the anterior part of the crown consists of a compressed cutting cusp. The heel has two well-developed posterior cusps. The third premolar has a similar prin- cipal trenchant cusp, but a smaller heel. Canines large. This genus differs from Herpetotherhim and Ictops in the simplicity of its fourth inferior premolar, and from Stypolophus and Deltatherium in the rudimental character of the accessory anterior cusps of the true molars, as well as in the three premolars. The rudimental anterior cusp of the true molars, with the three similar true molars, separates it from Palceoni/ctis, and the presence of a conic inner cusp of the same indicates it as different from Amhlyctonus and Periptychus. It is not possible to state whether Triisodon must be placed in the AmUyctonidce or not, on account of the absence of the superior molar teeth of the typical species T. quivirensis. This specimen of the type species of this genus is instructive as show- ing the succession of premolar teeth. Both the thii-d and fourth premolars have temporary predecessors. The predecessor of the fourth premolar dif- fers much from it in form, and is essentially identical in all respects with the true permanent molars. The crown of the predecessor of the third i)re- molar is wanting, the roots only remaining in the jaw. The i)ermanent third premolar was protruded before the permanent fourth. Which temporary tooth of Triisodon is homologous with the single one of the Marsupialia pointed out by Professor Flower!' As the addi- ■ Transactions of the Royal Society, 1867, p. 631. CREODOXTA. 271 tional permanent teeth of the placental Mammalia must have appeared later in time than the one already found in the implacentals, they must be those later protruded; hence the fourth tooth in the jaw of Tri'isodon must be re- garded as homologous with the fourth premolar of a placental, which is the last of that series to appear. If this be true, the tooth which follows the shed tooth of the marsupials is not the fourth premolar, as supposed by Professor Flower, but the third premolar. This view is coniirmed by the fact that the milk-tooth displaced by the fourth tooth in Triisodon resembles in all respects the true molai's, just as the permanent tooth occupying the same position does in Didelphys and some extinct Eocene genera. This goes to show that this tooth, permanent in marsupials, is temporary in placentals, and that, in spite of its form in the former group, it is the fourth premolar and not the first true molar, as supposed by Professor Flower. Thus the posterior milk-molar of diphyodonts is a permanent tooth in the MarsupiaUa. This observation confirms my conclusion that the Creodonta form a group intermediate between the MarsupiaUa and Carnivora} I may add that in Triisodon the inferior border of the lower jaw is not inflected pos- teriorly. Four species of this genus are known, which differ in some points of dental structure as well as in size. Their characters are as follows: I. Internal anterior cusp of inferior true molars very small and well separated from external anterior cusp. Length of inferior true molars .044 ..T. quiviremis. II. Internal anterior cusp of inferior true molars larger and nearly connected with the external. Heel of inferior true mol-'rs simple; length of true molars .023; smaller . . T. levisanus. Length of inferior second true molar .011; heel with several lobes; larger. T. heilprinianus. Length of inferior true molars .052; heel with two tubercles; largest T. conidens. The .superior molar teeth show a resemblance to those of Mesonyx and also to those of DeUatheriwm. Among the Mesonychidce, Tri'isodon approaches Sarcothraustes in the form of the inferior molars, in the expanded heel. On the other hand, the appearance of the anterior cusp of the inferior molars approaches what is seen in Amhlydonus. The small transverse posterior superior molar of Triisodon further distinguishes it from Amblycfonus. A 'Proceedings Academy Pliiladelpliia, 1875 (November 30). 272 THE rUERCO FAUNA. series of modifications of the dental characters, proceeding from the simple to the more complex, may be constructed as follows: 1. Mesonyx; 2. Dissa- cus; 3. Sarcothraustes ; 4. Triisodon; 5. Amhlydonus ; 6. Deltatherium. The first three belong to the Mesoni/chidce, as distinguished by the form of the tarsal articulations. Whether Triisodon must be arranged with Amhlydonus or not, cannot be ascertained until the foot structure is known. As the number of the inferior premolars in three of the species now referred to this genus is unknown, it is possible that some of them ma}' be hereafter referred to Ictops. Triisodon quivirensis Cope. Loci Bupra citati. Plate XXV. c ; fig. 2. Represented by both rami of the mandible, which exhibit alveoli or crowns of all the teeth excepting the incisors. Size about that of the wolf. Inferior canine directed upwards, its section nearly elliptic; a faint posterior, no anterior cutting edge. Fourth premolar rather large, with an anterior basal cingulum whicli is angulate upwards, and is not continued on the inner side of the crown. Cusps of the heel each sending a ridge forwards, the internal lower, obtuse, and descending to base of inner side of large cusp; the external larger, with an acute anterior cutting edge continuous with the cutting edge of the large cusp. True molars with an external, but no internal basal cingulum. Border of heel with one large and three smaller tubei'cles, the former with, the latter without, anterior cutting edge. En- amel of all the teeth nearly smooth. All the cusps are rather obtuse. Measurcmenf.1. L<-n<;tIi of inferior molar series 080 Long diameter of base of canine 013 Length of true moiar series 044 Lentil of ba-se of Pm. iv 016 Elevation of crown of do 014 Length of bnso of M. ii 010 Width of do. in front OH Elevation of do 014 The measurements of the jaw are not given, as the animal is not adult, the last molar not being yet fully protruded. CEEODONTA. 273 From the lower Puerco Eocene beds of New Mexico, near the Canyon Largo, a branch of the great canyon of the San Juan Eiver. Triisodon heilpkinianus Cope. Proceedings American Philosophical Society, 1881, p. 193. Paleontological Bulletin, No. 34, p. 193, Feb. 20th, 1862. Plate XXVIII a; fig. 2. This species may be readily recognized as smaller than the T. quivi- rensis, and as having the anterior inner cusp of the inferior true molar of larger proportions than in the corresponding teeth of the latter species. It is only represented in my collection by a portion of a lower jaw, which supports only one well-preserved molar. As the fourth premolar is not present, it is not positively ascertained that the species does not belong to Idops. The anterior cusp is very low, and is nearer the inside than the middle of the anterior border. The principal anterior cusps are opposite, and the external is a little the larger. The heel is larger than the basis of the an- terior cusps, and has convex borders. Its internal border supports three tubercles, and the external border rises into a cutting lobe with lenticular section. Enamel smooth. No cingula, but the external base is injured. Measurements. M. . , (of cusps 0070 p-ert.cal|^f^^^j O^.g Biameters of inferior molar ; I anteroposterior 0110 V transverse 0i.'65 Puerco beds of New Mexico. Dedicated to my friend, Professor Angelo Heilprin, of Philadelphia, who has contributed to our knowledge of the fauna and geology of the Eocene period. Triisodon levisanus Cope. Proceedings American Philosophical Society, 1883, p. 446. Plate XXIV f ; fig. 3. This creodont is represented by a part of a right mandibular ramus, which contains the fourth premolar minus its principal cusp, and the first and second true molars, with the alveoli of the third. The ramus is deep, and probably belonged to an animal of about the size of the red fox. The 18 c 274 THE PUEKCO FAUNA. molars h.ave the structure most like that of the T. heilprinianus, especially anteriorly. The principal anterior cusps are united together for most of their elevation, while the anterior inner is much smaller and lower, and is situated between the middle and inner side of the anterior cusp. The heel is rather wide, and has a raised border. The external part of it is angular, and is somewhat within the vertical line of the base of the crown. The fourth premolar differs from that of the type of the genus, T. quivirensis, in having two acute longitudinal tubercles situated close together on the heel. The anterior masseteric ridge is very prominent The masseteric fossa is strongly concave, but shallows gradually inferiorly. Its inferior border presents a low thickened ridge, which is recurved in front. This may be an individual character only. The inferior outline of the ramus is generally convex, and does not rise much below the masseteric fossa. Measurements. M. Length of last four inferior molars 0315 " " true molars 02:W „. ,,. . ( iiiittTonosterior 0065 Diameters of M. i.S . ,>,,.. ( t ran verso OOoo Length of Pm. iv. on base 0090 Depth of ramus at M. i O-JOO Thickness" " 0065 This Tritsodon is not only materially smaller than the T. heilprmianus, but differs in the characters of the heel of the inferior molars. In that species the internal border is tubercular; in this one it is entire. The T. conidens and T. quivirensis differ in the arrangement of the anterior cusps. Dedicated to my friend, Henry Carvill Lewis, professor of mineralogy and geology in the Academy of Natural Sciences, Philadeli)hia. From the Puerco epoch of New Mexico, discovered by D. Baldwin. Triisodon conidens Cope. Proceedings Academy Natural Sciences, Philadelphia, 1882, p. 297. Plate XXIII d; figa. 9-10. A right maxillary bone and corresponding mandibular i-amus represent this species in my collection. The former sustains the last five molars, and the latter the last three, with alveoli of the others and of the canine tooth. The pieces indicate a skull of the size of that of the wolf, and a good deal more robu.st in its vertical measurements. CREODONTA. 275 The third superior premolar has a base of triangular outline, the ex- ternal side longer than either of the internal, which are connected by a broadly rounded angle. The external cusp is of lenticular section at the base, and circular section near the apex. An internal cusp is represented by a strong cingulum, as in Periptychiis, which connects with the posterior base of the external cusp. Tlie crown of the fourth superior premolar has .a triangular base of which the anterior side is shorter than either of the other two, which are subequal. The external cusp is large, simple, and subconic. The internal is distinct but smaller, and is continued posteriorly as a cingulum to the posterior base of the external cusp. No internal cin- gulum. The crown of the first true molar is worn to the roots. The sec- ond true molar is the longest of the series. Its base is a triangle, placed transversely to the axis of the jaw, of which the external side is the* shortest, the anterior the next longer, and the posterior the longest. The apex or internal extremity of the crown is obtusely rounded. There are two sub- equal external cusps, which are injured in the specimen. The internal cusp is the apex of a V whose limbs form the anterior and posterior edges of the grinding face of the crown, extending outwards to near the bases of the external cusps. Posterior to the posterior one is a strong basal cingulum. No internal, and a feint anterior cingulum. There is probably an external ■cingulum, but it is broken away. The last molar is of an oval outline placed transversely to the cranial axis, both the external and internal extremities contracted, the latter a little more so. There is a large anterior external conical cusp. The posterior external is small, and is situated at ihe posterior third of the posterior border of the crown. The internal cusp is well developed, and has a subcircular section. There are strong external ^nd posterior cingula, and a weak anterior one, but no internal cingulum. The posterior extremity of the maxillary bone within the zygoma, is imme- diately above the posterior border of the last superior molar. Measurements of superior molars. M. Length of bases of posterior five 069 _. . , Ti ... ( .luteioposterior 013 Diameters base, Pm. in < ' ._„ ( transverse WH Ts. , , T> • < anteroposterior 0145 Dianaeters base, Pm. iv •; ■ ... ( transverse Ul4 276 THE PUERCO FAUNA. u. Length baseof trae molars - 039 Diameters baae of M.ii I ''°'"°P°^*"'°^ ^^'^ I transverse 021 Diameters base, M. h; < anteroposterior 010 ( transverse 0175 Elevation of base of zygoma above base of M. iii 018 The ramus of the lower jaw is, as usually with the Creodonta, deeper and less robust than that of Carnivora of corresponding size. It is also more compressed than that of the Ty'iisodon quivirensis. It retains its depth to below the canine teeth, and does not shallow below the middle of the coronoid process, where also there is no tendency to inflection. The ante- rior masseteric ridge is not very prominent, and the masseteric fossa is not defined below, nor is the inferior edge of the ramus prominent or ridged at that point. The premolar teeth are lost, but they occupied but a short space, and were probably only three in number. The first and second true molai's are subequal, while the third is a little smaller than either. Each consists of an anterior higher and a posterior lower portion, the lower region being at the junction of the two. The anterior part has a nearly circular section, and contracts towards the apex. The latter is divided into three cusps, a larger external and two lesser internal. The external and posterior internal soon fuse on wearing, and their combined section is a crescent. The anterior inner is small, and stands near the inner edge of the crown, and not at the middle as in T. quivirensis, and is circular in section. The heel of the tooth rises to its posterior border, which is divided into two cusps. Each of these sends a ridge forwards towards the base of the anterior cone of the tooth. The external is the larger, and reaches that base. The internal is smaller, and falls short of it. The posterior inferior molar differs from the others in form as well as in size. There is no posterior inner anterior cusp, the large external cusp being supplemented by a small anterior internal only, which sends a little ridge downwards and posteriorly. The heel is narrowed, and supports the two cusps on its posterior border in contact, and not separate as on the other teeth. The external is the larger, and extends forwards to the base of the anterior cone near its middle. Some remnants of hard matrix leave it uncertain whether there is a small median posterior marginal tubercle on the first and second molars or not CREODONTA. 277 The first inferior true molar has a strong external cingulum ; the second has none ; the third has one, which is most evident between the cusps, is weaker at the base of the posterior lobe, and faint at the anterior lobe. No internal cingula. Measurements. M. Length of true molar series 052 Length from M. iii to anterior masseteric ridge 013 Diameters of M-i^^^t^'"?"*^*""' l]], I transverse Olio T^. . - ■,, ..(anteroposterior 018 Diameters of M. u < ' ., , < transverse Oil Diameters of M. iii 5 *'^**^°P°«*«"'"' • *'^*^ ( transverse 0105 Depth of ramus at M. iii 047 Width of ramus at M. iii inferiorly 013 The molar teeth of this species are more like those of the T. heilprin- ianus than those of the T. quivirensis. This is seen in the more conic char- acter of the anterior lobe of the tooth, and the better development of the anterior inner cusp. The species is a good deal larger than the T. quivirensis. From the Puerco beds of N. W. New Mexico, D. Baldwin. DELTATHERIUM Cope. American Naturalist, 1881, March 25, p. 337, Lipodectes Cope, 1. c, 18S1, p. 101-9. Dental formula : I. ^; C. p Pm. p M. |-. Superior premolars, the first and second with simple crowns, the third with one large external cusp and an internal small one. The fourth premolar with a large, simple external cusp and a prominent internal one. The first and second true molars with triangular bases, supporting two external compressed conic cusps and a subtriangular internal one. Last molar similar in its internal portions, the external part narrow. A wide diastema in the lower jaw. Inferior premolars simple, two rooted. True molars with anterior inner cusj) well developed, forming with the anterior external a sectional edge, as in Stypoloi^lms. Heels well developed, much produced, and supporting a special tubercle in the last molar. The superior molars of this genus may be distinguished from those of Pelycodus by the absence of the intermediate tubercle and of the posterior internal tubercle. They differ from tliose of Esthonyx in the absence or 278 THE rUERCO FAUNA. weakness of the posterior inner tubercle, and in the absence of the ear-like expansion of the external angles. The number of possible combinations of tubercular and tubercular- sectorial molar teeth is considerable, and many of them are represented in the genera of the Creodonta. Deltatherium is a genus which has, in the lower jaw, two tubercular sectorials, and a third with a long heel posterior to them. The genus thus stands between Stypolophus and Dkhjmictis, but is nearer the former than the latter, since it has three true molars. It differs further from both in having but three premolars and a wide diastema. The canine is well developed. Although there is a tubercular tooth, the cutting apparatus is well developed, and indicates more than usually rapacious habits. There is as yet but one species known. It is allied to Leptktis, and agrees with Mops and Mesodectes in possessing an internal tubercle of the third superior premolar, but differs from both in having but one external cusp of the fourth superior premolar, resembling in this respect the more typical Oxyanidce. With this genus we enter a series of forms in which the dentition is more decidedly opossum-like than in those previously considered. Besides Beltatherimn there are species of the Eocene which I have referred to the Miocene genera Ictops and Perafherium, and there are the as yet purely Miocene genera Leptictis and Mesodectes. The Eocene Diacodon must be referred to the same category. Leptictis differs from DidcJphijs in having but two superior incisors on each side instead of four; Ictops bicuspis has three on each side. Diacodon differs in not having the anterior inner cusp of Didelphys, and in Ictops it is present, but small. This character will serve to distinguish these genera empirically from Stypolophus, as will also the development of cusps on the heels of the molars. Deltatherilwi fundaminis Cope. American Naturalist, 1H«0, March, p. 3S8. Lipodfctes penetrans Cope 1. c. 18?1, p. 1019. Plates XXIII p, figs. 8-11; XXV a, fig. 10; XXV .1, fig. 3. Represented by specimens which display the dentition of both max- illary bones minus the canines, and l>y several mandibles. The most instructive specimen includes the cranium anterior to the sagittal crest with. CEEODONTA. 279 dentition, with several fragments of the posterior part of the skull, with parts of both mandibular rami suppoi'ting several teeth, with parts of hume- rus and ulna. These specimens show that the Deltatherium fundaminis and Lipodectes penetrans are one and the same species. Besides this, there are separate mandibles of two other individuals, making five in all. In the first-named specimen the second premolar is convex on the inner face; the base of the third is a nearly equilateral triangle. The bases of the true molars are triangles, with bases external. The internal angle sup- ports an acute cusp, and has a posterior basal cingulum, which is very strong in the last three molars. The two external cusps of the first and second molars are situated well within the base, which is folded into a strong cin- gulum. This cingulum develops strong anterior and posterior angles. This is the largest species of the family yet discovered. Measurements. Extent of series of last six molars 045 Extent of series of true molars "26 Diameters of fourth premolar? f eropo c transverse uu/o- ^. ^ . , . , (anteroposterior 0087 Diameters of second true molar <; .,„f. ( transverse uiui; The type specimen of the Lipodectes penetrans is a left mandibular ramus, with three of the molars preserved The last has a long heel ; the first and second true molars are alike, and resemble those of Tritsodon, but the appendicular cusps are better developed. The anterior inner cusp is, however, smaller than the others and is nearly median in position. The heel is elevated on its external border into a strong triangular cusp. The posterior border rises into an acute cusp, which is internal to the middle line. The internal border of the heel is not elevated, and the surface is the oblique inner face of the external cusp. The anterior cusps are only moderately elevated and the cusps are acute. The enamel is smooth, and there is a low cingulum on the external base. The first (second) premolar is two-rooted, and has a large base. The second (third) consists principally of an elevated cusp with a subtriangular section. The heel is very small and acute, and there is no anterior basal tubercle. The internal face is strongly grooved in front. Canines directed upwards, with robust base. Symphysis short. Length of molar series, .043; of premolars, .019; of diastema, .012; length 280 THE PUERCO FAUNA. of base of last molar, .010; do. of canine, .007; depth of ramus at last molar, .018; of diastema, 015. As large as, but more robust than, the red fox. The third specimen above mentioned is somewhat injured by pressure, but exhibits the following characters The sagittal crest rises from an ascending frontal region, so that the profile is concave. The muzzle is short, and is contracted behind the alveolae of the canine teeth. The latter are prominent, and the premaxillary region is short and rather wide. The super- ciliary ridges are rather promirtent and terminate in postorbital angles, which are rather prominent. This is due to the abruptness of the convergence of the anterior temporal borders, which are angles, and not ridges. The ante- rior, and probably the posterior, part of the brain cavity is tery narrow. The postglenoid process is prominent, and there is no ti-ace of preglenoid ridge. There is a large postglenoid foramen, and the infraorbital foramen issues above the middle of the third premolar. The lachrymal foramen is small, and is entirely within the jireorbital border. The posterior nareal opening is small, not exceeding in width the space which separates it on each side from the internal border of the last molai*. Of the three incisors the external is the least, and it is separated by a wide diastema from the canine. The latter is large and the crown is directed vertically downwards. The crowns are mostly broken off, but enough remains to show that the posterior edge is acute, and is bounded within by a wide, shallow groove, and by a less marked groove externally. There is a distinct but short diastema behind the canine. The first (sec- ond) premolar is a flattened acute cone, with an acute posterior edge. The base of the third premolar is triangular in section, but the internal pi'ojec- tion does not support a cusp. The anterior and posterior basal cusps are nidiinental. The fourth premolar has an internal cusp which sends a ridge downwards and outwards on the anterior side of the crown. There is an anterior but no posterior basal lobe, which does not rise into a cusp. Pos- terior or basal cingulum weak. In the true molars the posterior external cusp is connected with the corresponding external angle of the crown by a ridge, while the anterior cusj) is not connected with the anterior angle. The external cusps are set in further on the second than on the first true CREODONTA. 281 molar. The last true molar is cut off obliquely on the external side and posteriorly, so that the posterior external cusp stands on the posterior ex-' ternal angle of the ci'own. The posterior cingulum is strong on all the true molars, and extends i-ound the inner base of the ci'own. It is strongest on the first and second, but does not rise into a cusp on either, as it does in Pelycodus and other forms. The probable inferior canine has a characteristic form. The crown is not elongate, and the section of its base is a half circle. Above the base the inner face becomes concave, a broad median ridge dividing the con- cavity into two grooves, which are less marked near the apex. There is a shallow groove external to the posterior edge, which is thus acute; apex, obtuse. The inferior molars, except the first and last true molars, have been described above The first true molar does not differ from the second. The anterior part of the third is just like that of the second, but the heel is much longer. I cannot give the details of its form, as the surface is in- jured. Measurements, M. Length of superior dental series from canine 043 Length of diastema 005 Length of premolar series 017 Diameters of canine^ ^°*«'°I'°**«"°'^ ^°^ < transverse OOG Length of precauine diastema 007 T^- . Ti • Mransverse 008 Diameters, Pm. iv< . „„. c anteroposterior 00/ Diameters, M. ii5 tr^^isverse 009 c anterposterior 008 TV- i ,r ... 5 transverse at middle 009 Diameters, M. iii< < anterposterior 006 Length from incisive border to jiostorbital angle 056 Width between superciliary edges 030 Length of true inferior molars 033 Length of last inferior molar 0098 Depth of ramus at M. ii 0155 This species was a half larger than the common opossum, and was much more robust. The typical specimen was found by Mr. D. Baldwin at the mouth of Canyon Largo, on the San Juan River, Northwestern New Mexico, in the Lower Eocene formation. Mr. Baldwin informs me that it came from below all the Wasatch Sandstones, which would place its horizon in the Puerco formation. The other specimens came from about the same position. 282 THE PFERCO FAUNA. Deltatherium BALinviNi Cope. Proceedings American Pliilosopkical Society, 1882, p. 463 (Nov.) Plate XXIII .1; lig. IS. 'Hiis Creodont is known only from a portion of a right mandibular ramus, which supports the two last premolars and the first true molar, with part of the second. It differs from the D. fundaminis in its materially smaller size, and in the forms of the teeth. The first true molar is a more robust tooth, and the basis of the posterior or heel crest is more rounded and less angu- late. The anterior inner cusp projects less anteriorly. The fourth pre- molar has a distinct anterior basal lobe, which is wanting in the D. funda- minis. Its heel is short and wide, and the posterior face of the principal cusp is flat, and there is a rudiment of an internal tubercle on its side. The second premolar is elevated and acute, has no anterior basal lobe, and has a very short, wide heel. Enamel slightly roughened. The animal was rather aged. Measurements. M. Length of Pni. ii and iii and M. i 0160 Diameters M.i^'"'t'''-"P''«t''"°^ ^'=^ < transverse 0040 Elevation of crown of Pin. iii 0052 Depth of mandible at M. i 0180 From the Puerco beds of Northwestern New Mexico. Dedicated to Mr. D. Baldwin, the discoverer of the niannnals and fauna of the Puerco beds, which is one of the most important in the history of American paleon- tology. Deltatherium lnterruptum Cope. Proceed. Anier. Philos. Soc, 1882, p. 463. Plate XXIII d; fig. 13. The smallest species of Ddtathcrimn is, like the D. hdldwini, only rep- resented by the anterior part of a right mandibular ramus, which suppoits the last premolar and the first true molar, with tlie bases of the other pre- molars and part of the canine. The canine is small, and the first premolar, in accordance with the generic character, is wanting. The second premo- lar is two-rooted. The fourth has an elevated principal cusp and a narrow CEEODONTA. 283 heel on the inner side of the posterior base; anterior base injured. The first true molar has very little sectorial character, and resembles the corre- sponding tooth of a Pelycodus. It differs entirely from that of the D. fmida- minis in the possession of a well-marked posterior internal cusp, which is connected by a ridge with the large internal lateral cusp of the heel. The anterior cusps of opposite sides subequal. A weak external basal cingulum on the anterior half of the crown; no internal cingulum. Enamel of the teeth wrinkled. Measurements. M. Length of premolar series 0140 Elevation of Pm. iv 0040 Diameters of M.i^''"*^™?"^*^"*"- "^^^^ ( transverse Wi'i Depth of ramus at Pro. i 0090 Depth of ramus at M i 0113 On comparison with the D. fundaminis, the first molar tooth has the same dimensions, but the premolars are considerably smaller. The ramus is also shallower. Found by Mr. Baldwin in the Puerco beds of Northwest- ern New Mexico. DIDELPHODUS Cope. American Naturalist, June, 1882, p. 522. ? 1 ? ^ 9 Dental formula: I. ^; C. -; Pm. ^; M. -. Second superior molar a simple cusp; third with an internal cusp; fourth with a simple external cusp without heel. True molars with two external cusps, set well in from the external border. Last superior molar narrowed and transverse. Inferior dentition like that of Stypoloplius, except that the fourth premolar has a small internal tubercle. Canine large. ' Symphysis not coossified. This genus differs from Deltatherium in the presence of an additional premolar tooth in the lower jaw. It is uncertain whether there is a first superior premolar, but I cannot find an alveolus for it. From Stypohplms it differs in the triangular character of the superior molars and the simple trenchant form of the fourth superior premolar. In the latter respect it is identical with Proviverra of Riitimeyer. I should refer the American spe- 284 THE WASATCH FAUNA. cies to this genus but for the tact that it appears to have but three superior premolars, wliile Prouivena has four. But one species is known. DiDELPHODUS ABSAHOK^ CopC. American Naturalist, 1882, June; Dellatherium absarokm Copo, 1. c. 1881, p. 669. Plate XXIV e; fig. 13. This animal repeats very closely the characters of the D. fundamims, but is much smaller in all its proportions. Both branches of the lower jaw accompany the anterior part of the skull, so that the dentition is well dis- played. There are three inferior tubercular-sectorial molars, as in Stypoh- phus, but the fourth premolar has an internal tubercle, which is not found in that genus. The same tooth has a rudimental heel, which sends an angle up on the inner side of the crown, which is then deflected and terminates below in the rudimental anterior basal tubercle. The apical angle is little produced, and constitutes the internal cusp above mentioned. The third inferior premolar is large, has a rudimental heel, and no inner lobe; the first premolar is two-rooted. There are only three inferior incisors. The inferior canines have an open groove on the inner side and a rib on the ex- ternal side. The latter is bounded anteriorly and posteriorly by a shallow open groove. The symphysis is long and oblique; it extends posteriorly to below the front of the third premolar. The posterior mental foramen is below the posterior side of the same tootli, and the anterior one is below the first premolar tooth. The superior molars are triangular, and the external posterior angle is not produced. The external cusp of the fourth premolar is compressed and simple, as in Proviverra; in Stypolophus {Prototomus) viverrinus and S. mul- ticuspis, that tooth has a conic cusp and large posterior heel. The crowns of the sQcond and third premolars are quite elongate and acute, and the third has a small posterior basal lobe. On the external base of the fourth are very small anterior and posterior lobes. The principal cusps of all the true molars are double, and stand on the middle of the transverse diameter of the crown. This leaves an extensive obliquely sloping external face, which terminates exteruall}' by a narrow cingulum. The two cusps are well CREODONTA. 285 separated from each other on all the true molars. The internal cusp is the apex of a V, each limb of which is continued into a cingulum along the anterior and posterior base of the crown. The external base of the first true molar is subequally bilobate, on the second the anterior lobe is pi-o- duced, and on the third the posterior lobe is only represented by a right angle between the external and posterior borders of the crown, which are of equal length. The second principal cusp is also reduced. Canines well developed. Enamel smootli. Measurements. M. Length of superior molar series 0216 Length of superior true molars 0107 Diameters of second true molars ^'*°*"°P''«*«'i''^ «033 c transverse 0055 Width of jaws at same tooth 022 Width bet ween bases of canines 008 Depth of ramus mandibuli at Pm. i 005 Depth of ramus mandibuli at M._iii 009 From the Wasatch Eocene of the Big-Horn River; J. L. Wortman. This species was an opossum-like animal of the size of the American weasel, Mustela americana. Its delicately acute teeth indicate a diet of in- sects, which no doubt abounded during the Wasatch epoch. STYPOLOPHUS Cope. Stypolophus Cope, Second Account New Vertebrata Bridger Eocene (Paleoutological Bulletin, No. 2), p. 1, Aug. 3, 1872, Proceed. Amer. Philos. Soc, 1872, p. 446; An. Eep. U. S. Geol. Surv. Terrs., 1872, p. 559. Protoiomus Cope, Rep. Vert. Foss. New Mexico, 1874, p. 13; System. Cat. Vert. Eocene New Mexico, U. S. Geol. Surv. W. of lOOtb Mer., 1875, p. 9. Cyiiohi/a-nodon Filhol, Comptes Eendus de la Soci^t^ Philomathlque, Paris, 1873. Eecherches sur 1. Phosphorites du Quercy, 1877, 227. Molars seven below, i. e., four premolars and three true molars, and prob- ably the same number above. Inferior true molars, consisting of three eleva- ted cusps in front and a low horizontally-expanded heel behind; the external cusp largest, the internal smallest, and the anterior intermediate, forming with the external a short sectorial blade. The inferior premolars two-rooted (the first only seen in S. caylusi, S. whitice, and 8. Mans) ; the crown con- sisting of a compressed cusp and short trenchant heel. Of the superior molars the last is narrow, transverse, and with a blade-like crown. The two preceding have crowns forming right-angled triangles in horizontal sec- 286 THE WASATCH AND BKIDGER FAUN^. tion, the right angle being the antero-extemal. The antero-posterior cutting- edge consists of two cus})s in the middle and a short blade at the posterior angle of the crown. The internal angle supports a cusp. The last premolar has a trilobate section at the base, and supports a median subconic cusp, a short posterior blade, and an internal tubercle. The second premolar is compressed without internal heel, and nitli a rudimental posterior one. (The first premolar is two-rooted in S. caylusi and S. Mans.) The species of StypoIo2)hus o( which I have obtained the best preserved remains is the S. viverrintis, an animal about the size of a domestic cat, from the Wasatch beds of New Mexico. Its mandibular bones and teeth are unknown, but I have derived from it the characters of the dentition of the maxillary bone, as above stated. The maxillary teeth of the S. muUicusi)is and S. aculeatus are similar in generic characters, and of these species I know almost the entire dentition of the lower jaw. The posterior part of the cranium of S. viverrintis displays a low sagittal crest. The supraocci- pital bone has a moderate extent on the upper surface of the cranium, supporting part of the sagittal crest, as well as the prominent oblique ones of the inion. The front is rather wide, and tlie nasal bones are flat, and but little naiTOwed posteriorly. The lachrymal foramen is large, and entirely within the prominent anterior margin of the orbit; it is of a verti- cally oval form. A suture extends from it postero-externally to the rim of the orbit, and then returns forward and upward on the facial surface, inclos- ing what I suppose to be the lachrymal bone. On cleaning the surface, I cannot trace any lachrymal bone posterior to the foramen, as is usual in Carnivora {Canis, Felis), and must therefore suppose that this genus pre- sents an external and anterior position of the lachrymal bone, as in Ungu- lates. The evidence of this arrangement is seen on both sides of the head. The foramen infraorbitato is large, and issues above the third premolar. The characters presented by the vertebrae are those of the Creodonta in general, with the following moditications: A cervical is of medium length, possesses a hypapophysial heel, which is produced downwards behind, and has but little trace of a neural spine. The neural arch is wide and flat above, and it is pierced on each side by a foramen not far from the lateral border. Two anterior lumbars from just behind the flying ribs, have no CEEODONTA. 287 diapophyses unless a small, narrow, broken area indicates the base of a very rudimental one This is at the anterior end of a strong- longitudinal ridge, which marks the inferior part of the side of the centrum The anapophy- ses* are strong, inclosing the anterior zygapophyses of the succeeding vertebra on the lower side. In Ursus ardos, Canis familiaris, and Felis catus there is no vertebra intervening between the last bearing a rib and the first bearing a diapophysis. In Ursus ardos, the centra are short, and the dia- pophysis occupies an elevated position. In Stypolophus viverrinus, the cen- trum is moderately elongate, and the ridge representing the diapophysis has an inferior position, resembling rather Canis and Felis in these particu- lai's. A portion of the sacrum preserved shows it to have been of robust proportions. Besides the superior intervertebral foramina, there is a small one each side of the neural arch in front of the posterior zygapophysial ridge. A caudal vertebra is relatively large in all its dimensions. A frag- ment of the femur shows that both the great and little trochanters are well developed, the former inclosing the usual fossa. The distal halves of both tibise are preserved, one of them adhering to a mass of the vertebrae. The shaft below the middle is subcylindric, while the distal end presents the peculiarity common to all the flesh-eaters of the Wasatch Eocene epoch. The astragalar surface is without groove, and is oblique, both transversely and longitudinally. The inner extremity of the bone is produced down- wards, fitting the inner oblique face of the astragalus, as well as the con- cavity of the side of the neck by its end. There are no strong ligamentous grooves. The bones of the feet are unknown. A comparison of such por- tions of the limb bones as I have observed (those of S. viverrinus) with those of Felis catus (domesticus), Canis familiaris, and Ursus ardos, has the following result: In the humerus the tuberosities are not so pronounced ; especially is the great tuberosity more produced upward and outward in the recent genera, whence the bicipital groove is deeper. In Ursus ardos the greater tuberosity is also produced more posteriorly, and in all of the species named, its posterior bounding ridge is more pronounced on the shaft than in P. viverrinus. The great trochanter of the femur has the elevated position of that of Felis and Canis rather than the depressed form of that * In my description of this genus in the Wheeler Reports, these processes were called metapophyses. 288 THE WASATCH AND BRIDGER FAHN^. of Ursus, and the compressed and moderately elevated distal end is that of the former two, rather than like the same region in the latter genus. The distal end of the tibia is unlike that of either of the three genera named, but resembles most that of Ursus. The entirely distinct character of the astra- galar articular extremity has been already described. The anterior end of the shaft is convex in S. viverrinus, flat in Felis and Canis; flat behind in the former, convex in the latter. The external end of the shaft is trans- verse in S. viverrinus, oblique in Canls and Fells; especially so in the former, being more or less parallel with the inner astragalar groove, while in S. viverrinus it diverges from the angle which represents the groove. The ten- dinous groove is wider and better defined than in G. familiaris, more resem- bling that in Felis. The inner malleolus is more anterior in position than in the two genera named, and beai-s a distal articular facet, which is wanting in Felis and Canis. As compared with Ursus arctos, the inner malleolus is more produced, and the outer distal border quite different, the truncate outline of Stypolophus being represented by a tuberosity. The anterior face of the shaft is convex in Stypolophus, concave in Ursus arctos; the pos- terior flat in the former, convex in the latter. The entire distal end of the tibia is more transversely expanded in Ursus. This genus, as now defined, is identical with that called by me in pre- vious papers on the paleontology of New Mexico, Prototomus. It may be frjund to be proper to use this name, but for the present I use an older one, which 1 proj)osed for similar Carnivores of the Bridger Eocene of Wyoming. Unfortunately, I am not able to state the number of the tubercular-sectorial molars of the S. pungens Cope, the type of the genus, as my specimens have only the last two in place. The structure of the separate molar teeth of both jaws is identical in the species from the two regions, and the generic characters of the dentition, so far as known, ai'e the same in the best pre- served species, S. multicuspis and S. viverrinus of the Wasatch, and S. acule- atus of the Bridger epochs. The three tubercular-sectorials in the lower jaw, and the two bicuspid molars in the upper, distinguish this genus from the allied Oxycena. M. Filhol has described very fully beautiful specimens of species of iS'jypolophus from the Phosphorites of southern central France. He names CREODONTA. 289 them Cynohycenodon caylmi and C. minor* Through the courtesy of M. Filhol I am in possession of specimens of the former, and I have examined the types of his descriptions. There can be no doubt of their pertinence to Stypolophus.f S. caylusi differs from S. multicuspis and S. aculeatus in the reduced elevation of the cusps of the first inferior true molar, and the greater obliquity of the superior molars. Professor GaudryJ has identified this genus with the Proviverra of Riitimeyer, which was proposed to receive a species ft-om the Swiss Eocene. I have examined casts of Riitimeyer's type, which includes the dentition of both jaws, and which are preserved in the laboratory in charge of Professor Gervais, in the Jardin des Plantes, to whom my acknowledgments are due. I find enough difference to induce me to believe that Proviverra and Stypolophus cannot be united, excepting by the discovery of species which shall show transitional features in the characters. The difi'erence is, that while in Stypoloplms the fourth superior premolar has an internal cusp and an external conical cusp flanked anteriorly and posteriorly by a basal heel, in Proviverra the external part of the crown is a single triangular trenchant cusp, and the internal heel is low, forming with the rest of the base of the crown, a right-angled triangle. This difference is significant, when we recol- lect that this tooth is the homologue of the sectorial in true Carnivora. Dr. Leidy has applied the name Sinopa to some flesh-eaters of the Bridger epoch without distinctive generic description. An examination of the typical specimen of the S. vorax, which Dr. Leidy kindly permitted me, shows that it differs from Stypoloplms in the rudimental character of the heel of the last molar, if the specimen is not deceptive. It is otherwise identical in the last four inferior molars. Species. I have referred five species of the Wasatch formation to this genus and a fourth provisionally (S. Mans). Three species of the Bridger epoch probably belong to it, which, with the two French species, make a total of ten. They may be distinguished as follows, with the imperfect material at my disposal. The molars measured are those of the inferior series ; in the case of the 8. viverrinus their length is estimated from those * Eecherches sur les Phosphorites dii Quercy, 1877, p. 227. tCope, Bull. U. S. Geol. Surv. Terrs., 1879, p. 43. % Enchainements du Monde Animal, 1878, p. 20. 19 o 290 THE WASATCH AND BKIDGER FAUNiE. of the superior series. The depth of tlie mandibular ramus is taken at the penultimate true molar. I. Length of true molars les.s tliau .0140. Length of true molar.s, .0135 ; premolars less extended 8. viverrinus. Length of true molar.s, .0112 ; premolars much larger S. minor. II. Length of true molars from .0180 to .0220. True molars, .0183; depth of ramus, .0080; first true molar small. . . S.cayluai. Tiue molars, .0200; depth of ramus, .0100; heels of molars large, wide 8. pungens. True molars, .0220 ; depth of ramus, .0125 8. secundarius. True molars, .0210; depth of ramus, .0150; heels large; first molar not reduced 8. multictispis. True molars, .0220; depth of ramus, .0150; heels very narrow and short ... 8. brevicaJcaratm. True molars, .0220 ; depth of ramus, .0180 ; heels elongate, basin- shaped 8. whitice. III. Length of true molars exceeding .0230. Length of true molars, .0235 ; depth of ramus, .0210, robust 8. strenuus. Length of true molars, .0250; premolars large; ramus slender; depth, .0140 8. aculeatus. There is some diversity in the form of the astragalus in the species above named. There may be two generic forms included here, the one having the astragalus without trochlear groove, represented by S viverri- nus., the other with the tibial articular face of that bone slightly concave, represented by the S. whitice. As the latter sti*ucture is the later in its appearance in time, it is presumably that of Stypolophus pungens, the tj^pe of the genus which is from the Bridger formation. For the older form, the name Protototnus (Cope, 1874) must be used. P viverrinus and P. Mans are certainly referable to it. Stypolophus insectivoeus Cope. Proceed. Amer. Philos. Soc, 1)J72, p. 4C9; Paloontological Bulletin No. :',, i>. 1, publUlied August?, 1872. Plato xxiv, figs. 10-11. Represented by a posterior molar and a premolar of the right side of an animal less than half the size of the S. pungens Cope. The molar pre- sents three anterior trihedral acute tubei'des, of whit-h the exterior is more elevated than tlie others. Its posterior plane forms one transverse face with CREODONTA. 291 that of the inner posterior. The posterior tubercular heel is low, and sup- ports an oblique ridge which bounds a deep groove behind the outer cusp, no doubt to receive the molar of the upper jaw. This arrangement is not seen in 8. pungens. The premolar is a flat cone with faint traces of a tubercle behind, and cingulum on inner side. Length of crowu molar , 0050 Height of inner cusp 0040 Length of heel 0025 Width of crown 0030 Height of crown piemolar 0040 . Length of crown premolar 0040 Found in the Eocene bad lands of Black's Fork by the writer. Stypolophus pungens Cope. Loc. cit., 1872, p. 466; Paleontologlcal Bulletin No. 2, p. 1, August 3, 1872. Plate xxiv, fig. 8. This is the type of the genus, and is represented by the posterior part of a mandibular ramus which supports the last two molars. The species is of medium size in the genus, and has a rather shallow mandibular ramus. The heels of the molars are well developed and have a raised border. The inner cusps are not much elevated, the external one much exceeding them. The masseteric fossa is well defined anteriorly, and a well-marked angle bounds it below. There are no cingula on the molars, and the enamel is smooth. The measurements are: M. Depth of ramus at last molar Oil Length of last molar 0072 Width of last molar, posteriorly 0040 Height of inner tubercle 0062 Height of external tubercle, anterior .0040 This species was about the size of the gray fox. From the bluffs of Cottonwood Creek, Wyoming. Stypolophus brevicalcaratus Cope. Loo. cit., p. 459; Paleontological Bulletin No. 3, p. 1, August 7, 1872. Plate xxiv, fig. 9. Established on a portion of the left mandibular ramus, containing the penultimate and antepenultimate molars, of an animal of larger size than 292 TUE WASATCH AND UKlDdEU FAUX^. the type of the genus, S. pungens. The molars have the general characters of the con-esponding ones of that species, but differ in their greater eleva- tion in comparison with their length, and the greater convexhy of the outer side. The shortness is occasioned by the abbreviation of the heel, which, in the last molar present, is very small and flat, and without keel or tuber- cle on its surface. That of the molar preceding it is larger, and presents in its elevated outer margin a trace of the keel seen in the smallest species, but it is also of reduced size. Enamel smooth. M. Length of two molars - 016 Length of penultimate crown 008 Width of penultimate crown 0047 Length of penultimate heel 002 Stypolophus WHITI.J: Cope. StypolophuK atremiHo Cope, Bull. U. S. Geo). Surv. Terrs., 1861, vi, p. V)2, not of 1675. Plato XXV 6, figs. 8-14. This species is represented by a right mandibular ramus which sup- ports all the molar teeth, and displays the alveolus of the canine, and lacks all posterior to the coronoid process. Also by a portion of the frontal bone, two vertebrae, fragments of scapula, humerus, ulna, radius, ilium, and tibia, and the greater part of both tarsi They represent a species larger than the Virginian opossum, and intermediate between the S. hrevicalcaratus and S. strennus in proportions. It has not the rudimental heels of the molars of the former species, nor the robustness of the latter. Tlie inferior outline of the mandible is gently curved from the canine to below the last molar. The anterior border of the masseteric fossa is well marked, but not the inferior border. The ramus is compressed and deep. Tlie canines have stout roots and narrow curved crowns. The first pre- molar is separated by a short space from the canine, and by a longer from the second premolar. It has either a single compressed root or two roots confluent within the alveolus. The crown is truncated obliquely behind. The second premolar is two-rooted and the crown is elevated anteriorly and depressed posteriorly. The third premolar is more symmetrical, but the heel is produced. It is narrow and keeled mediiilly. The fourth premolar is abruptly larger than the third. Its crown is simple, except a low tubercle CEEODONTA. 293 at the anterior base and a short trenchant heel at the posterior base. Of the three tubercular-sectorials the first is the smaller. The heels of all three are rather narrowed and elongate. The margin is raised all round, inclos- ing a basin; a notch in the external margin cuts its anterior part into a tubercle. The two internal tubercles are rather obtuse, and are consider- ably shorter than the external cusp. Measurements. M. Xength from cauiue to end of last molar 060 X/Cngth from canine to tirst true molar 037 Xength from cauiue to secoml premolar 015 Xength of base of fourth premolar 009 Elevation of fourth premolar 007 Xength of base of second true molar 007 Xength of heel of second true molar 00"26 Elevation of second true molar ^ 009 Depth of ranuis at third premolar 015 Xength of superior canine 028 Xength of crown of superior canine with enamel 012 A portion of the frontal bone shows weak anterior temporal ridges uniting early into a sagittal crest, Avhich is low as far as preserved. The parietal bones overlap the frontal as far forwards as the temjDoral ridges. Anterior to the latter the front is concave in transverse section. Viewed from below, the spaces for the olfactoiy lobes are large and entirely anterior to those which received the anterior lobes of the hemispheres; each one is about as wide as long. In the small part of the cerebral chamber wall left there is no indication of convolutions, wliicli would be visible in a gyren- cephalous brain; two air-chambers in front of each olfactory lobe. The base of the transverse process of the atlas is perforated from behind to the middle of its inferior side ; from the latter opening a foramen penetrates directly into the neural canal. A posterior dorsal vertebra has the centrum longer than wide and much depressed. Its inferior face is regularly convex in section. The proximal end of the scapula shows that its posterior border is much thickened, and tliat the spine arises abruptly and near to the glenoid cavity. There appears to have been scarcely any cora- coid ; the surface adjoining it is, however, injured. The humerus lacks the proximal portion, and the inner half of the condyles with the epicondyles. The deltoid crest is not very prominent, so that the shaft is rather slender. 294 THK WASATCH AM» lilUDGEK FATTN.E. The external di.stal niaig-inal crest is thin, and is continued well up on the shaft. The external part of the condyle displays no intertrochlear ridge. Olecranar and coronoid fossae well marked. The olecranon is robust and deep, and is truncate posteriorly and below. The head of the radius is a regular transverse stout oval. A fragment of the ilium from near the acetabulum displays a promi- nent "anterior inferior spine." The best preserved tarsus includes calca- neum, astragalus, cuboid, and navicular bones. The tibial face of the astragalus is strongly convex anteroposteriorly and slightly concave trans- versely. The head is prolonged some distance beyond the distal extremity of the calcaneum, and presents a convex internal border and a concave external one. Its long axis is parallel to that of the tibial portion, but is not in the same axis, owing to its lateral position. The external face of the trochlear portion is vertical, and is interrupted by a deep fossa behind. The internal face is very oblique, and passes into the superior face of the head. The posterior face of the trochlea is grooved with a wide and shal- low groove, which just reaches the superior face, terminating on the exter- nal side. The superior face is not grooved, but is shallowly concave in transverse section. The head is a transverse oval, and is convex ; it has a small facet for the cuboid on the outer side. The heel of the calcaneum is large and expands distally, so as to be as wide as deep. The convex astragalar facet is very oblique to the long axis of the calcaneum ; the sustentaculum is rather small. Below the latter is a narrow tuberosity looking downwards and forwards. On the external side, close to the cuboid facet, is a depressed crest. The cuboid facet is as deep as wide. The cuboid bone is a little longer than wide proximally, and narrows distally. It has a narrow astragaline facet and a deep fossa below proximally. The hook inclosing the groove for the tendon of the flexor muscle is prominent. The navicular is rather small, and has three inferior facets, which diminish in size outwards. It has a strong posterior knob-like process, with a narrow neck. When the t^irsal bones are in position, and the tibia stands vertically on the astragalus, the cuboid bone is turned inferiorly. This indicates that this species walked on the outer edge of the hinder foot CREODONTA. 295 Broken metapodial bones are slender and straight. The proximal end of a metacai-pal does not display the interlocking lateral articulation. Two phalanges are depressed in form. Measurements. M. ( anteroposterior 0145 Diameters of a dorsal centrum.? vertical 0075 ( transverse 0115 Diameters of glenoid cavity scapula ^^°'''™P°8*e"°'' ^^^S < transverse 0090 Depth of olecranon 0110 Width of bead of radius , 0110 Width of neck of ilium anteroposteriorly 0120 Diameter of shaft of tibia at middle 0085 e anteroposterior 0180 Diameters of astragalus^ greatest J of trochlea 0140 ' transverse ( of head 0100 Length of head 0070 Length of calcaneum 0300 Width of calcaneum at sustentaculum .0140 Width of cuboid facet 0066 Length of cuboid 0120 , , .( anteroposterior J '^t^l ^'^"^ Diameters of cuboid.^ I proximal 0075 ( transverse proximal 0098 vertical 0050 transverse 0100 Diameters of navicnlar < anteroposterior^ ^•*'>t'i^«™«ity 0100 c without tuberosity 0070 As already remarked, it is possible that the semi-grooved trochlea of the astragalus of this species is an indication that the genus Prototomus must be retained as distinct from Stypolopkus, to which the present species probably truly belongs. The specimen described, together with the mandibular ramus of an- other, supporting the last two molar teeth, were found in the bad lands of Wind River, Wyoming, by Mr. J. L. Wortman. A third specimen was found by Mr. Wortman in the true Wasatch bed of the Big Horn River region. This includes a large part of a skull, with one mandibular ramus almost perfect, with an incomplete ulna and fibula. With the aid of the lower jaw I have restored the skull (see Plate XXV d; fig. 1), the occipital region only being inferential. This I have modeled after that of Stypolo- phus caylusi Filh., of which I possess a cast given me by the kindness of Dr. Filliol. 296 THE WASATCH AND BRIDGER FAUN^. The skull is larger than that of the red fox, and resembles in general proportions that of the opossum. The brain-case is narrow, and the sagittal crest is elevated. The muzzle is contracted but not short, and the palate is wide posteriorly. One character of the Creodonta, in which they resemble the opossums, is seen in the relatively small size of the molar teeth. There is no trace of preglenoid crest. The premaxillary bone is narrow, and its superior process does not reach near to the frontal. Its inferior lateral aspect is excavated for the apex of the inferior canine tooth. The nasal bones have a short free extremity, together forming an angulate semicii-cle, and do not extend beyond the vertical line of the anterior border of the canine teeth. The front is very wide, much exceeding the proportions in S. caylml, and equaling one-half the length from the premaxillary border to the union of the temporal ridges. The latter are low and rather trans- verse. There are no postorbital processes, and the angle is very obtuse. The sagittal crest grows higher posteriorly. The posterior border of the palate is transverse, and a little concave, and is thickened. Between the processus triangularis and the alveolus of the M. iii there is first a notch and then a short process. The maxillary bone is excavated between the true molar teeth. The malar bones are thin and shallow. They have no postorbital angle. The glenoid cavity extends on the zygomatic process of the squamosal, and terminates in a rounded border. The incisor foramina are short and rather wide. The infraorbital fora- men is large, vertical, and above the postei'ior root of the fourth premolar. There is no postzygomatic foramen. There are three closely placed superior incisors on each side, of which the external is separated from the canine by an interspace equal to the widths of two of them. The canine is large, and has a robust root; the crown is lost. A short diastema separates it from the first premolar, wliit-li has two well-developed roots. A very short space separates these from the anterior root of the second premolar. The roots of the remaining molars are adjacent. The crowns of all the true molars, and that of the fourth pre- molar, are preserved; the others are lost. The fourth jjremolar has the character of other species of the genus. Externally there is a median cone, a posterior distinct heel, and a low anterior basal lobe. The internal lobe CEEODONTA. 297 IS prominent inwards, but is not elevated. A weak external cinguluni. In the first and second true molars the external cusp is double, and stands considerably within the external border, less so on the first than in the second tooth. In the first the anterior border is transverse, and the poste- rior border considerably longer and oblique. The internal angle is promi- nent, but without cusp; the anterior external basal lobe is very small, while the posterior is elongate, and has an acute edge, which forms with the pos- terior side of the posterior cone a sectorial blade. The latter feature is seen in a more striking degree in the second true molar; the transverse diameter is greater, so that the posterior border is less oblique. The anterior border is transverse, and the external border is openly emarginate, which is not the case with the first true molar. The last true molar is entirely transverse and narrow. It has one median cusp, which is connected by a cutting ante- rior edge with the internal tubercle and the external border. The mandibular ramus is compressed, and the horizontal portion is rather deep, most so below the last molars. The inferior border is gently convex downwards, and then rises below the coronoid process. It is slig'htly decurved again below the condyle, and is then recurved, terminat- ing in the apex of the hook-like angle. This hook is larger than in most Creo- donta and Carnivora, projecting a short distance beyond the condyle. Be- tween them the posterior border is deeply excavated. The condyle has its superior border nearly straight. Its posterior articular face extends to the inferior side at the internal extremity, and is cut off obliquely from the mid- dle below to the external superior extremity above. The coronoid process is wide anteroposteriorly, and has a regularly convex superior border. This terminates in an angle looking downwards and backwards above the con- dyle. The masseteric fossa is well marked, but is not defined below. There are two mental foramina, one below tlie third, the other below tlie anterior part of the premolar. The inferior canine is a robust tooth, with rather short crown. Both internal and external faces display a median longitudinal angle. There are short spaces before and behind the first premolar tooth. The latter has two roots and a short crown, which is obliquely truncate posteriorly. The second premolar has a larger crown than the thu-d. It has no anterior or 298 THE WASATCH AND BRIDGER FAUN^. posterior basal lobes, but the posterior face is concave. The third pre- molar has a distinct though short posterior heel. The fourth premolar has the posterior heel with a medan cutting edge ; there is a small anterior basal lobe. There is no internal lobe, nor the i-udiment of it, as seen in DicMphodeus ahsarokce. The first true molar is smaller than the second and third, which ai-e nearly equal. The heels of all the true molars have a raised border, which incloses a basin ; the inner wall is notched at its junc- tion with the base of the principal cusp. The two inner cusps are of about equal elevation, and are much less elevated than the external one. The enamel of all the teeth in both jaws is smooth. The symphysis mandibuli forms but a slight bevel of the general sur- face, is not strongly sutural, and does not extend posterior to the second premolai-. The ulna is rather robust. The section of the shaft is triangular, the base upwards representing the section of a plane on which the radius rests. This plane turns to a slope of 45° inwards near the distal part of the shaft, where it is at first bounded by sharp superior and interior ridges. The infe- rior edge is obtuse, and the inner and outer sides are concave, especially the external. The distal extremity of the tibia is expanded and its malleolar face is oblique, and not vertical, as in true carnivora. A compressed pro- cess projects posteriorly in the plane of the posterior face, and is separated from the posterointernal angular border by a shallow groove. No groove or process on the external face, as is seen in Canis. Mea«uremetits. M. Length of palate 073 Width of palate at last molar teeth 029 Width of palate at first premolar teeth 0115 Width of posterior niires 0117 Width of nasal hones at middle 0116 Width of frontal belweeu orhits 0385 e anteroposterior 001)."> Diametersofhaseofcanine^j^^^^^g^ 006^, Length of premolar series 033 Length of base of first premolar 0068 - ., , ( fore and aft 008 Diiimetcrs fonrth premolar^ „. ( transverse Wt Length of trne molars 019 ,. ^ -^ , < fore and aft 008 Diameter second trne molar i „ „ ( transvM^rse UlUa CEEODONTA. 299 M. Length of mandible with condyle 109 Elevation at coronoid process — 052 Elevation of condyle 027 Elevation at last molar 021 Elevation at first premolar 013 Thickness at first tnie molar 008 Length of molars from canine 059 Depth of ulna at middle 010 Anteroposterior width of distal end of fibnla, with process 012 The Stypolophus tvJiitice is dedicated to Frances Emily White, M. D., the professor of physiology in the Woman's Medical College of Pennsylvania. I insert here what should have been noted under the head of the sub- order Creodonta; the successional modifications of the superior molar teeth to be seen in the various genera of this group. In ilfioc?oE«M5-and in some of the teeth of Mesonyx the extremes are to be observed, viz : In the former two well-separated conic external tubercles, and in the latter but one. In Deltatherium and PeratJierium these tubercles are flattened externally, and directed inwards in true Didelpliold fsishion. In Didelpliodus and Stypoloplms they are close together and more conic, but the angle extending from the posterior cusp foreshadows a sectorial blade. In Pterodon and OxycBua this blade is realized, and the two cusps are flattened and nearly fused, producing a type of sectorial peculiar to the family of the Oxyoenidoe. Stypolophus acdleatus Cope. Report Capt. G. M. Wheeler, U. S. Geog. Geol. Surv W. of 100th Mer., iv, pt. ii, p. 112. Tricodon aculeaius Cope, Proceed. Amer. Philos. Soc, 1872, p. 460. Paleontological Bulletin No. 1, p. 1, July 29, 1872. Plate XXIV, figs. 6-7 ; XXVII, figs 1-2. This species was first described from a premolar and a true molar, teeth of the inferior series. I now give a description of a considerable part of the dentition of both jaws. I am enabled to do this through the 300 THE WASATCU AND BKIDGER FAUN^. kindness of Professor Gnyot of Princeton College, who placed at my disposal a specimen acqxiired by him for the beautiful museum under his direction. The Princeton specimen agrees precisely witli my type in its corre- sponding parts. It indicates the largest species of the genus, with the possible exception of S. hians, and one of about the size of the red fox, or ii little larger. The last superior molar, although narrower than the others, has a triangular outline, the posterior angle being nearly right. Its anterior face is straight. The crown bears three cusps, of which the interior is the most robust, the median the smallest, and the exterior the most acute. The latter is bounded by a low cutting edge on each side, extending from the base to the anterior and posterior external angles. The penultimate superior molar is subrectangular in outline, the right angle being external and anterior, and the internal being obtusely rounded. The two external median char- acteristic cusps are lenticular in section, and acute. At the inner and marginal base of each is a low tubercle, the posterior one rudimental. These inclose a basin with the larger inner cusp; round the base of the latter is a distinct cingulum. The antepenultimate molar is lost. The preceding one has a single large conical cusp and a posterior low cutting heel on the external side ; also a low basal tubercle in front. The inner lobe of the crown is rather large, and is contracted so as not to originate from the entire inner side of the external portion. It supports an inner cusp only, and has no basal cingulum. Measurements of superior molars. M. LcDgtli of posterior four molars 041 Length of the anti'rior, on base 010 Wiiltli of the .intorior, on base 009 Lengtli of penult iinati', on base ..1 000 Width of penult iniato, on base Oil LenKth of last molar, on base 004 Width of last molar, on base 009 The mandibular ramus is rather compi'essed. The masseteric fossa is well marked and is bounded by a strong ridge in fi'ont, but has no distinct border below. The front of the base of the coronoid process is con- cave, and its inner border is the most prominent. A short space separates CEEODONTA. 301 the last molar from it. The second true molar is the largest, and the first and third are of about the same size, and not much smaller than the second. The last differs from the first in having the heel narrower in transverse diam- eter. The heels are all basins with the external wall somewhat within the base of the crown. The anterior part of the crown is much elevated above the heel, and consists of the usual three cusps, whose base forms a right- angled triangle, of which the shearing portion forms the hypothenuse. The last premolar is large, rather longer than the first true molar. Its crown consists of a large conic median cusp of wide lenticular section, behind which is a heel with obtuse cutting edge, and an internal basal cingulum. There is a well-marked anterior basal tubercle, and a rudiment of a posterior lobe of the median cusp. No lateral cingula. Of the other premolars it can only be said that the base of the third is as large as that of the fourth. Measurements of inferior molars. M. Length of last four molars on base 0355 Length of true molars on hase 025 Length of first true molar on base 0083 Width of first true molar on base 0050 Length ef second true molar on base 009 Width of second true molar on base 0058 Length of third true molar on base 008 Length of heel of third 0035 MIACIS Cope. Paleoutological Bulletin, No. .i, p. 2, Aug. 7, 1872. Proceed. Amer. Philos. Soe., 1872, 470. Uiniacyon Leidy, nomen nudum, Proc. Acad. Nat. Sci. Phila., 1872, p. 277 (December, not published until 1873). Report U. S. Geol. Surv. Terrs., i,p. 118, nomen nudum. This genus was proposed for a species which was represented at the time by a portion of a mandibular ramus, which had supported the last three molars. The portions of the latter preserved were stated to resemble corresponding parts of Canidce, with approximations to those of Stypoloplms. Subsequently Dr. Leidy described the mandibular ramus, containing most of the teeth, of a larger species; and a fragment of the lower jaw of a still larger species. From the former of these specimens I derive the greater part of the following diagnosis. I premise with the statement that there are in this specimen five premolar teeth, the third of which is apparently three- rooted, and stands partially transversely to the axis of the jaw. I suspect 302 THE WASATCH AND BKIDGER FATING. this tooth to be an abnormal production, and do not propose to include it in the generic diagnosis. I have pointed out a similar example in the inferior dentition of the Coryphodon latidens* Dentition below; I. I C. 1 ; Pm.; M. 3; first premolar one-rooted; first true molar with a broad heel, one edge of which is submedian and a little elevated above the other. Last two molars tubercular, the second with conic tubercles in front and a short heel posteriorly. This genus appears to be the canine representative among the flesh- eaters of the Eocene, as Oxyoena is the feline. There is no more reason for suspecting it of Marsupial affinities, as is suggested by Leidy, than in the case of any others of the Creodonta. The fact that the well-preserved infe- lior border of the ramus of the M. edax is not inflected, is evidence to the contrary. The five species of Miacis diff"er in their measurements as follows : That of M. vorax is derived from Leidy; those of M. edax from the typical specimen, which Professor Leidy kindly lent me. a Last inferior molar with two roots. Length of inferior molar series, M. .042 ; of true molars, .020 ; depth of ramus at M. II, .016 M. canavua. Length of inferior molars, .037; of true molars, .018; depth of ramus at M. II, .013 M. brevirostris. a a Laiit inferior raolar with one root. Length of last three molars on base, .013; depth of ramus atM. II, .008. M. parvivorus. Length of last three molars on base, .014 ; depth of ramus at M. II, .010. 21. edax. Length of last three molars, .017 M. vorax. Miacis canavus Cope. Bnlletin U. S. Geol. Surv. Terrs., vi, p. 189, February 26, 1881. Established on the mandibular rami of two individuals, which display the roots and some of the crowns of all the teeth exclusive of the incisors. The root of the canine indicates that the crown is of large size and compressed at the base. The first premolar is one-rooted, and is separated from the second by a short diastema. The second has two well-distin- guished roots, which are separated from those of the third by a diastema like that in front of them. Posterior to this there are no diastemata. The •See Report Cnptnin Wheeler's Expl. 8nrv. W. of 100th Mer., iv, pt. ii, p. 215. CREODOKTA. 303 second root of the fourth premolar is much larger than the anterior. The sectorial, though the largest tooth, is of but moderate dimensions ; its heel supports two posterior tubercles. The first tubercular is a little shorter. It presents the three anterior tubercles of the sectorial, but they are obtuse and placed close together. The heel is well developed, and its external border is elevated into a ridge, which extends obliquely inwards and for- wards. The second tubercular is a very small tooth, but has two roots, the pos- terior of which is posterior to the anterior border of the ascending ramus. According to Leidy's measurements, this species is about the size of his M. vorax of the Bridger formation. That species has, Hke the two others of that horizon, a second tubercular tooth with only one root. Measurements. u. Length of dental line posterior to caniues 0440 Length of premolar series ^'^^ Length of base of fourth premolar 0065 Length of base of sectorial ■ OOoo Length of base of first tubercular 0060 Length of base of second tubercular 0040 Depth of ramus at second premolar : 0150 Depth of ramus at secoud true molar 0100 From the Wind River beds of Wyoming, J. L. Wortman. MlACIS BREVIROSTRIS Cope. BuUetin U. S. Geol. Surv. Terrs., v,p. 190, February 26, 1881. This species differs from those of the Bridger epoch in the same way that M. canavus does, *. e., in the biadicate last inferior molar. Its dimen- sions are intermediate between those of M. edax and M. vorax, hence a Uttle smaller than those of the M. canavus. This difference is partially seen in the shortening of the premolar series of teeth They are closer together than in the M. canavus, and the roots are larger. The sectorial tooth is shorter. The fourth premolar has a low anterior basal cingulum; the pos- terior part of the crown is robust. The first tubercular molar is wide, and consists of a basin-shaped heel and a short anterior portion which is more elevated. The latter consists of two cusps, which are connected by an anteriorly convex ledge, but there is no third anterior tubercle as in M.parvi- vorus. The nmiiis is quite robu.st, and the basis of the canine tooth is 304 THE WASATCH AND BKIDGEK FAUNJB. unusually large. Mental foramina are below the anterior parts of the sec- ond and fourth premolars, respectively. Last inferior molar small. Measurements. M. Length of molar series 03eO Length of premolars OiJOO Length of base of fourth premolar 0060 Length of b;ise of sectorial 0072 Length of base of first tubercular 0048 Length of base of second tubercular tKJ42 Depth of ramus at second premolar t'UO Depth of ramus at second true molar 0140 Wind River beds, J. L. Wortman. MlACIS PARVIVORUS CopC. Paleontologlcal Bulletin, No. 3, p. 2, Aug. 7, 1872. Proceed. Amer. Philos. See, 1872, p. 470. Viverravu* parrivorus Cope, Pal. BnU., No. 12, p. 3. An. Rep. U. S. Geol. Surv. Terrs., 1872 (1873), p. 560. Plate sxiv, fig. 12. Established on a portion of the right ramus mandibuli, containing por- tions of three molars, the penultimate being perfect. As in Canidcc, the molars diminish in size posteriorly, the last being single-rooted, the penulti- mate being two-rooted. The structure of that tooth is approximately that of StypolopJms, i. e., •with three trihedral cusps in front and a heel behind, but the cusps are of equal height, and their point of union not raised above the surface of the heel. This is a valley bounded by a sharp margin, which is incurved to the outer cusp, leaving a vertical groove on the outer side, as in Stypolopltus sp. This species is further characterized by the single-rooted small tubercular posterior molar, which is also present in M. edax and 3f. vorax. The antepenultimate molar is much larger than the penultimate. The crown of the latter -is laterally expanded, and bears a cingulum at the base anteroexternally. Enamel smooth. Depth of ramus at penultimate molar 0080 Length of crown of penultimate molar 0040 Elevation of crown of penultimate molar .' 0025 Width ol crown of penultimate molar 0033 Found on Black's Fork of Green River. DIDYMICTIS Cope. Bystfim. Cat. Vert. Eocene New Mexico, U. S. Gcog. Snrv. W. of lUUth .M., 1870, p. 11. Kept. U. & Goog. Sunr. W. 100th M., vol. iv, part 2, p. 123. Inferior molars six, consisting of four premolars and two true molai-s. True molars, a posterior tubercular, and an anteri(u- tubercular-sectorial, CKEODONTA. 305 i. e., with three elevated cusps and a posterior heel. Premolars with a lobe behind the principal cusp. The canine teeth are directed forwards, and are very close together, so that it is doubtful whether there were any incisors. An ungual phalange of the typical species is strongly compressed. The humerus in this genus is distally expanded transversely, and the margin is pierced by tlie humeral artery. The astragalus exhibits two entire trochlear faces; the wider external and directed interosuperiorly, the inner presenting superointeriorly. They are separated by an obtuse longi- tudinal angle, and are little or not at all concave transversely. The form is depressed. The head supports a single transverse convex facet for the navicular, and, with the neck, is as long as the trochlear portion. In this genus the sectorial tooth of the lower jaw is of a very primitive type, resembling especially inferior molars of marsupials of carnivorous habits. This is seen in the close approximation of the anterior cusp to the two immediately succeeding it, and in its relatively small elevation in com- parison with the external cusp. The latter is much elevated in this genus. The heel of the same tooth is low; its length is in direct relation to the size of the species; that is, it is relatively shortest in the smallest species. The rudi- mental sectorial cusps of the tubercular tooth in B. liaydenianus show that ■ but few changes of form are necessary to connect the inferior dentition of this genus with that of Oxycena. The longest known species of this genus is the D. protenus, from the Wasatch formation of New Mexico. Three additional species were after- wards discovered by Mr. J. L. Wortmau in the Wind River country of Wyoming. The species range from the size of a mink to that of a coyote. Their characters are as follows, as derived from the mandibular teeth: I. Inferior tubercular molar with the three anterior cusps well developed. Length true luolar.s .0125 ; last molar narrow D. haydenianus. II. Inferior tubercular with rudimental cusps. * Inferior tubercular molar oval in outline, with a heel. Length true molars .025; last three premolars .035; last molar short J), altidens. Length true molars .019 — .020; last three premolars .036; last molar elongate D. protemis. Length true molars .016 — .018; last three premolars .028^.030; last molar narrow. D. leptomylus. 20 0 306 TUE WASATCn AND BRIDGEK FAUN^. Length true molars .010; last threepremolars.01,'35; last molar narrow.. i).dajf^-in«ian««. •• Inferior tubercular molar short, subquadrate iu outline. Length true molars .Oil ; depth of ramus at sectorial .010 2>. massetericus. Length true molars .018; depth of ramus at sectorial .017 X). curtidens. DlDYMICTlS HAYDENIANUS Cope. Proceed. Amer. Philos. Soc., leda, p. -IC-J. Paleoutological Bulletiu Xo. 35, p. 464, 1882, Nov. 11. Plate XXIII e, C^'s. 12-13. This Creodont is represented by parts of the maxillary and mandibular bones of the left side, the former supporting the four and the latter sup- porting the three last molars. The arrangement of the superior molars is much as in D. protenus, the fourth premolar being a true sectorial. The third premolar has no internal lobe, although the section of the base of the crown is narrowly triangular. It has anterior and posterior basal lobes, and a posterior lobe on the cutting edge. In the sectorial the median lobe is a good deal more produced than the posterior, though the two form together the usual blade. The anterior basal lobe is distinct, and the internal is larger and is conic. The first true molar has the anterior external base of the crown produced. Its two external cusps are conic and distinct. The internal part of the crown is rounded and supports a conic internal tubercle, which is separated from the external cones by two small concentric tuber- cles. The second true molar is considerably smaller, and is transverse, its external border being very oblique. It has an acute internal lobe. The character of the species is well marked in the inferior true molars. The first has the form seen in other species of Bidymktis. The heel is large, and with a median basin between lateral cutting edges. The two anterior inner cusps are of equal elevation and are near together ; the exter- nal is much larger. The last molar is elongate, but reduced in size. Its anterior three cusps, rudimental in other species, are here elevated, forming the triangular mass seen in the first true molar. They are not so elevated, however, as in that tooth, and thus not so much developed as in Oxyopia, Sh/polopkus, etc. The fourth premolar has a median cutting edge on the short heel. CREODONTA. 307 Measurements. M. Length last four superior molars 022 Length Pm. iii 0065 Length Pm. iv 0085 Width Pm. iv 0050 anteroposterior OO.'iS transverse 0088 oblique external '. 0072 Diameters M.ii^^"t<'^°P''^"^™'' 0027 ( transverse = 0055 ■rx. . ■ i- • nr ■< anteroposterior 007 Diameters interior M. i < ^ < transverse 005 _. , • i. • 111 ..(anteroposterior 0055 Diameters inferior M. ii < ' ( transverse 003 Depth of ramus at M. ii (squeezed) . 010 The peculiar characters of the last inferior molar distinguish this species from its congeners. The last superior molar is relatively smaller than in the D. protenus. In size this species is equal to the D. dawkinsianus, and is smaller than the D. leptomylus. As already remarked, the inferior denti- tion approaches that of Oxycena. A slightly-increased development of the anterior cusps of the last (second) inferior true molar would give two infe- rior tubercular sectorial molars, as in that genus. The superior dentition is, however, totally different, for there is no approach in the first true molar to the sectorial type characteristic of the Oxycenidce. It is dedicated to the distinguished geologist, Dr. F. V. Hayden. Puerco epoch of New Mexico; D. Baldwin. DiDYMICTIS ALTIDENS Cope. Bulletin U. S. Geol. Surv. Terrs., vi, 1881, Feb. 26, 190. American Naturalist, 1880, Oct. 746. Plate XXV a, figs. 13-14. This species is represented in my collection by the jaws of four indi- viduals in a fragmentary condition. One of these supported the last five inferior molars ; in others the inferior molars are separate from the jaws. 308 THE WASATCH AND BKIDGER FAUN^. The tubercular molar is relatively small in this species, not exceeding the average size of that of D. jyrotenus, while the sectorial is considei-ably larger. The anteroposterior diameter of the fourth premolar is equal to that of the sectorial, and that of the third premolar is a little less. The premolars are closely placed, the first not seen. The fourth premolar is not much widened posteriorly, and the lobe of the posterior edge is well marked. The cuspidate part of the sectorial is about equal in anteroposterior diameter to the length of the heel. The external cusp is much higher than the two interior, and the latter are equal in elevation. They are all obtuse, as are the continous edges which repre- sent the blade of the sectorial tooth of a higher carnivore. The length of the heel from the base of the internal tubercle is equal to the height of the latter. It carries a ridge-like tubercle, which extends from its posterior external border forwards and inwards. Between its inner side and the inter- nal rim of the heel is an "oblique concavity. The tubercular in its details is a reduced copy of the sectorial, the anterior cusps being represented by low tubercles and occupying relatively very little space. The posterior oblique tubercle and concavity are there. The crown differs from that of the sectorial in having the external basal cingulum stronger ; there is no internal basal cingulum on either tooth. No internal, and a trace of exter- nal cingulum on the fourth premolar. The mandibular ramus is compressed and deep. The masseteric fossa is well defined below as well as anteriorly. There is a well defined area of insertion (? for the internal pterygoid muscle) on the inner side of the base of the coronoid process. Measurements. No. 1. u. Length of bases of last five inferior molars O^SO _. , -. _.. , ( aiitiTopoHlcrior 0150 Diameters of fourth premolar < ,v^.- ( trausviTso OOOo rv- . r »i 1 < uiitiToiiostorior 0145 Diameters first tme molar < n,, ^ ( (ransvcrsc W)9K) T-v- » ,^ , ( aiitfriipoMtfrior '-"Os^ Diameters secoml true molar I ' nivo < Ir.iiisvrrso uuo.: Depth ramus ot second tme molar 0250 CREODONTA. 309 No. 2. M. Anteroposterior length of sectorial 0150 Length of heel OOG Elevation of external side of crown anteriorly 01& Width at same point 009 Length of crown of tubercular 009 Elevation anteriorly 005 Width of same 006 Wind River beds, Wyoming. J. L. Wortman. DiDYMICTIS LEPTOMYLUS CoPE. American Naturalist, 1880, Dec, p. 908; Bulletin U. S. Geol. Surv. Terrs., 1881, vi, p. 191. Plate XXV a; fig. 12. The specimens which I refer at present to this species belong to two varieties, which may perhaps be specifically distinct ; but this cannot be demonstrated at present They differ in dimensions only. Thus the true molars of the type, which comes from the Wind River beds, measure M. .016 in length. Five specimens from the Big Horn basin agree in having this dimension .018. The entire inferior molar series is only a little shorter than that of the smaller variety of the D. protenus from New Mexico. (See my report to Captain Wheeler, Plate XXXIX.) The species is characterized by the narrow and relatively elongate form of the tubercular molar. Its heel is considerably produced behind the posterior oblique ridge, which is not the case in the D. altidens. Its anterior part has the three low cusps well defined and close together, and behind them is the oblique longitudinal cutting edge. The middle of the posterior margin rises into a tubercle. The external cusp of the tubercular-sectorial is much elevated. The heel has a strong external cutting edge and internal ledge, which reaches the posterior border, and is not quite so long as the internal tubercle is high- The cusps are rather obtuse, especially the internal pair, which are of equal height. The representative of the blade is not very sharp. There are no basal cingula on these teeth. ii. Length of tubercular-sectorial 009 Width of same 005 Length of tubercular 007 Width of same in front 004 Big Horn basin, Wyoming. J. L. Wortman. 310 THE WASATCH FAUNA. DlDYMICTIS DAWKINSIANUS CoPE. Balletin U. 8. Geol. Surv. Terrs., vi, 1881, Feb. 26, p. 191. Plato XXV a; fig. 11. This flesh-eater is represented by more or less imperfect mandibular rami of ten individuals. The most complete of these lacks only the por- tions posterior to the coronoid process, and those anterior to the first pre- molar, and supports all the teeth excepting the first and second premolars. The premolars are all two-rooted excepting the first. The base of the fourth premolar is considerably longer than that of the third. Both of these teeth have a short posterior heel, and above it a cutting lobe. The fourth has a well-marked anterior basal tubercle. The heel of the sec- torial is relatively short, and the anterior portion of the tooth elevated. The anterior and inner cusps are high, and about equal, but the external cusp is much hiffher. The external border of the heel is more elevated than the inner. The tubercular molar is elongate, and has a small triangular ante- rior portion somewhat elevated, in slight resemblance to the sectorial tooth. This portion consists of two opposite cusps and a lower one in front of the anterior inner, which connects with the external by an anterior ledge. The posterior portion has a tubercle on the external side, besides a posterior elevation. The ramus is rather slender, and the masseteric fossa is bounded by a prominent ridge in front, but fades out below. The measurements show this to be the smallest species of the genus, being much less than D. leptomylus. Measurements. Length of dental series, including first premolar OuHi'i Length of premolar series 016S Length of h.ise of fourth premolar - .0055 Li'Hjith of base of sectorial 005^ Width of base of sectorial at middle -_- 0035 Elevation of sectorial 0055 Length of first trno molar 0044 Width of first true molar in front 0028 Elevation of first true molar in front 0025 Depth of ramus at second premolar 00(54 Depth of ramus at tubercular molar ""■" Tliis species is dedicated to my friend Prof. W. Boyd Dawkiiis, the distinguished geologist and paleontologist, of Manchester, England. P^ive specimens were obtained from the Wind River basin, and five fiom that of the Big Horn, Wyoming Territory. • CREODONTA. 311 DiDYMICTIS PROTENUS CoPE. Plate XXV d, figs. 4,5. System. Cat. Vert. Eocene New Mexico, U. S. Geog. Survs. W. of 100 M., 1875, p. 11. Report upon U. S. Geog. Survs. of W. 100 M. In charge of First Lieut. Geo. M. Wheeler, Corps of Engi- neers, U. S. Army, under the direction of Brig. Gen. A. A. Humphreys, Chief of Engineers U. S. Army ; Part II, Vol. IV, Paleontology, 1877, p. 123. Washington. Paleontological Bulletin No. 34, p. 159, Feb. 20, 1882. Jaws, more or less complete, of six individuals from the Big Horn basin, are referable to this species. They agree closely in measurements and belong to the larger variety of the species figured on Plate XXXIX of the report to Captain Wheeler. A left maxillary bone containing the last four molars furnishes the best characters for this part of both genus and species yet obtained. The third premolar has no interior lobe, but the inner base is more convex than the external, and has a low cingulum. There is a short posterior heel, and a shorter anterior basal tubercle. The fourth premolar has three external lobes, and an internal conic lobe which is opposite to the space between the ante- rior and middle external lobes. The anterior external lobe is the smallest and is subconical. The middle lobe is a flattened cone with a three-sided base. The third lobe is a blade directed outwards as well as backwards. Its free edge forms, with the posterior edge of the middle lobe, a sectorial blade divided by a median fissure. The first true molar is triangular, with the longest side anterior and the external and posterior sides equal. The external side is very oblique, subtending an obtuse angle with the posterior ide. It is also concave medially, and the anterior lobe projects outwards and forwards. The two external cusps are small, conic, well separated, and situated much inside of the external border. The internal cusp is large, and is separated from the externals by a small triangular tubercle on each border of the crown. Each of the latter descends into a cingulum which extends outwards. A strong cingulum surrounds the internal base of the crown, disappearing at the intermediate tubercles mentioned. The second true molar is much smaller than the first, and the details of its structure are the same. The anterior exterior angle is not so much produced. The fourth premolar is as effective a sectorial tooth as that of the spe- 312 TOE WASATCH FAUNA. cies of Gahcynns and Temuocyon, aiul has tlie anterior basal tubercle which is wanting' to that genus but present in Aclnrodon. Measurements. M. Lenj^th of last four molars 040 Leugth of third premolar Oil Width of third premolar ; 006 Diameters sectorial $ anteroposterior 015 ( transverse 010 Diameters first molar J '"'*"<'1'°»*«"°'" 008 ( transverse 015 Diameters second molar J «'^*«^°P°«'*^'"'°'" 0«5 c transverse COS) DiDYMICTIS MASSETERICUS Cope. Paleontological Bulletin No. 34, p. 160, 1882, Feb. 20. Proceed. Amer. Philos. Soc, 18.S1, p. 15!), Feb. 1832. Plate XXIV e; fig. U. This species is intermediate in size between the D. hptomylus and the D. dawkinsianus, and is characterized by the peculiar form of its tubercular molar, and the deeply excavated masseteric fossa. It appears to have been a rare species, as only one mandibular ramus was found by Mr. "Wortman. This is broken off in front of the fourth premolar, and supports the last three molar teeth. The tubercular molar is subquadrate in form, and consists of three low tubercles in front, and a wide heel behind, which has an elevated posterior border. The tubercular-sectorial has a short and narrow heel. Its anterior cusps are not very acute, and the two internal are equal, and a good deal shorter than the external. The fourth premolar is relatively shorter than in any other sp^ies of the genus, and the posterior marginal lobe is a mere thickening of the edge of the heel. Tliere is a low anterior basal tubercle. The enamel is smooth. The ramus is compressed and not deep. The angle is prominent, and is not inflected; it does not extend so far posteriorly as the posterior Ijordcr of the condvle. The inferior border of the masseteric fossa is an antrular line, without abrupt excavation, but the face of the fossa descends rapidly. The anterior border of the fossa is abiiipt and is formed by the usual sub- vertical ridge. CREODONTA. 313 Measurements. M. Length between Pm. iv and condyle, inclusive 0520 Length of posterior three molars 0170 Length of tubercnlar-sectorial 0070 Elevation of tubercular-seetorial 0070 Depth of ramus at sectorial 0100 From the Big-Horn River, Wyoming. DlDYMICTIS CURTIDENS Cope, Paleoutological Bulletin No. 34, p. 160, Feb. 20, 1882. Proceed. Amer. Philos. Soc, 1882, Dec. p. 160. Plate XXIV d; fig. 10. As in the case of D. massetericus the present species is represented by a single fragmentary mandibular ramus. This supports a sectorial tooth of the size and form of that of the B. protenus, and is thus much larger than that of the species just named. This tooth is placed nearer to the base of the coronoid process than is seen in any other species, and only leaves space for a short tubercular tooth. This is lost from the specimen, but the alveolus shows pretty clearly its small dimensions. The base of the fourth premolar remains, and it is evident that this tooth was like that of D. protenus in form and proportions. The base of the posterior marginal lobe is present. The ramus is deeper and larger than in the D. massetericus. Measurements. M. Length of bases of last three molars 0285 Length of bases of fourth premolar 012O Length of bases of sectorial on base 012 Width of bases in front 008 Depth of ramus at sectorial 017 Big Horn basin. J. L. Wortman. 0XYJ^:NA Cope. Report on Vertebrate Fossils obtained by the Wheeler Survey in New Mexico, 1874, p. 11 (extracted from Report of Lieut. Wheeler to Chief of Engineers). System. Cat. Vert. Eocene New Mexico, 1875, p. 9. Report U. S. Geog. Survs. W. of 100th Mer., p. 95. Dental formula: I. ^7;; C. — ; Pm. — ; M. — -. Two small median su- sO 1 4 2 perior incisors and a very large external one separated by a diastema from the canine. The latter is large, and is followed with little interval by the first premolar. The two last premolars and all the molars of the supe- 314 THE WASATCH FAUNA. rior series with an internal heel; the last molar transverse; third and fourth upper premolars with an anterior cone and posterior cutting-lobe; the first true molar with two anterior acute cones, the posterior forming a sectorial edge with the posterior lobe ; last superior molar with a single trenchant edge. In the mandibular dentition, the canine teeth are directed forward and upward without intervening incisors. First premolar one-rooted; second and third consisting of an anterior elevated cone and posterior heel, which is elevated and trenchant in the middle. The fourth premolar is nearly similar, with the posterior tubercle sharp-edged. The two true mo- lars with an anterior elevated portion and small, low heel; the former con- sisting of three acute tubercles, of which the largest or exterior fonns with the anterior a sectorial blade oblique to the axis of the mandibular bone. The exterior portion of the posterior transverse superior molar is a transverse blade, interior to which is one or probably two subtriangular cusps. The blade shuts down in contact with the plane posterior face of the united middle cusps of the last inferior molar, and the cusp shuts down on the inner side of the heel of the same, where the surface is often seen to be worn obliquely by it. The elevated cusps of the last inferior molar close into a deep fossa of the maxillary bone; the blades of the external and anterior cusps shearing against the inner side of the posterior median cusp and posterior blade of the penultimate superior molar. The inner heel of the latter opposes transversely the posterior heel of the penultimate inferior molar, shearing somewhat with the posterior border of tlie united median cusps. The external and anterior cusps of the penultimate inferior molar, with their external shear, fit within the median cusp and posterior blade of the antepenultimate superior molar, and are received into a correspond- ing pit of the maxillary bone, which is not so deep as the postei-ior fossa. The surface of the maxillary between this tooth and the last premolar is only slightly concave. Thns, in this genus, and the arrangement is similar in Stypolophus, each inferior tubercular-sectorial tooth makes two shears with two corresponding superior molars, viz, a posterior-transverse with the superior molar behind it, and an external-oblique with the superior molar corresponding to it This does not occur in any i-ecent Carnivora, and is a more cnm|ilex, although nuich less powerful, arrangement than they possess. The skull in this genus is robust. In the O.forcipata there is an elevated CEEODONTA. 315 sagittal crest, and the supeiior walls of the cranium are massive. The crest divides on the posterior part of the frontal region, and disappears. The z_ygomata are short and deep, and laterally expanded. The malar bone rises in a strong postorbital process, partially inclosing the orbits, as in the Cats. The angle of the mandible is not inflected in the least degree. The scapula has a well-developed coracoid hook. The spine rises abruptly from near the glenoid fossa. The tuberosities of the hume- rus are not very prominent, and are separated by a rather wide bicip- ital groove. The deltoid crest is continuous with the edge of the greater tuberosity and is quite prominent. At the distal extremity there is an epitrochlear foramen. The condyle has the internal flange and external cylinder of carnivorous mammalia, the cylinder with a deep notch on the posterior inferior face, the inner border of the notch continuing into a flange on the posterior side. The epicondyles are not so much expanded as in the species of Stypolophus and other forms of Creodonta. The head of the radius is a regular transverse oval. The only irregularity is a slight con- cavity of the superior border. The face is gently concave, with a point directed proximad on the superior border. The carpal extremity of the radius is triangular. The surrounding tuberosities are distinct. The carpal extremity of the ulna is somewhat like the head of a rib in its obliquity and its distal and lateral tuberosities. But few bones of the fore foot are pre- served. The most important is the cuneiform, which difiers much from that of the Carnivora, but resembles that of Estlionyx. It is flat and not oblique. The unciform facet is concave, and about as large as each of the two supe- rior facets. The latter are transverse and subequal, and are little concave, and are separated by an obtuse ridge. The bone resembles the cunei- form of Ursus more than that of Proci/on, and still less those of Canis and Felts. It differs from Ursus in its less obliquity and its external production into a tuberosity. The proximate ends of the first, second, and fifth meta- carpals are a good deal like those of Ursus, but the trapezial facet of the pollex is more concave in the transverse direction than in that genus. In a fragmentary skeleton of probably 0. morsitans a portion of the ilium is preserved. It exhibits a tuberosity above the acetabulum which represents the " anterior inferior spinous process" of human anatomy, and is larger than in the existing genera Ursus, Canis, and Felis. The ischium 31G THE WASATCH FAUNA. is wide and flat, and its posterior external thin edge is prominent proximad to the spine. The latter is an nnimportant angle a considerable distance beyond tlie line of the acetabulum. In Dkleljihi/s and Sarcophilus it is want- ing, while in Phascolardos and nearly all forms of Carnivora it is near the posterior line of the acetabulum. The only exception I find is in the Viver- ridce, where a Herpestes has it in much tlie same position as in Oxycena. The superior border is, however, not expanded. The middle of the shaft of the femur is wanting in all our specimens of this genus. The proximal portion of that of 0. morsitam, is wide and flat, and has a large great trochanter about equal in elevation to the head, which does not inclose a deep or large fossa. The fossa for the ligamentum teres is at the fundus of a deep emargination of the rim of the head. The distal part of the femur is flattened as in Amhlyctonus, and the patellar groove is not elevated as in Stypolophus viverrinus, but wide, although less so than in the Bears. The head of the tibia displays a spine and median groove, but the crest is not prominent. The distal end of the tibia exhibits the ungrooved astragalar surface of the other Oxycenidce, with abruptly projecting internal malleolus. Its border is less regular than in other genera described. The outer extremity is nar- rowed, and gives rise to a longitudinal external ridge of the lower part of the shaft, and there is a tuberosity on the posterior and one on the inner side of the lower extremity. The posterior as well as the anterior astragalar border is angulate at the base of the malleolar process. Tlie tendinous grooves are shallow. The astragalus is like that of Sarcophilus and different from that of Didclphjs and Phascolardos in the absence of the oblique fibular facet, which is here vertical and lateral. The trochlea is slightly concave above, and the malleolar facet does not present so oblique a face as in Didymictis. It dillers from the marsupial genera, and resembles the carnivorous in its large neck and head. The proximal part of the calcaneum displays the usual two astragalar facets well separated. It is remarkable for the obliquity of the facet for the cuboid, which presents upward as well as forward (when ill the .supine position). The calcaneum is wide, especially in its postero- iuferior face, and the ))Osterior free portion is narrow and oblique, indicating !t plantigrade habit. Its flatness exceeds that in Ursus arctos, and the ex- CEEODONTA. 317 panse of the anterior portion is similar to that genus, while greater than in Canis and Felis. The obliquity of the cuboid facet is not seen in either of the recent genera named. The navicular is shallow, cup-shaped, and has three distal facets and an internal tuberosity. The cuboid is a very char- acteristic bone, and is unlike that of any other genus known to me. The proximal or calcaneal face is very oblique to the long axis of the bone, pre- senting outwards when the axis is placed antero-posteriorly. It is, how- ever, evident that the long axis diverges from that of the foot, outwards. A more truly proximal facet is the rather wide one for the astragalus, which makes a right angle with that for the calcaneum. Owing to the divergence of this bone from the others, the ectocuneiform articulated with it as much as with the navicular, an arrangement seen in Bidelphys. It is possible that the hinder foot may have been divided somewhat as in some of the lemurs, the two external digits antagonizing the three internal. Cuneiforms lost. The metatarsals preserved include the I, II, III, and V of one foot, and the I, III, and IV of the other. They resemble much those of Ursiis. The first has no lateral facets for II, and its facet is not more concave than in TJrsus; hence it was not probably opposable. The II is the onl}^ one with concave transverse section; that of the others is convex in both directions. They underlap each other from the external inwards, as in va- rious carnivora. The V presents a considerable proximal free process out- wards Numerous phalanges have been obtained. They are depressed, with their distal articular facets slightly emarginate. None of them present the triangular section characteristic of many recent Carnivora. Their pro- portions are not different from those seen in the Urstis arctos. A claw is moderately compressed, and terminates abruptly and obtusely. The ex- tremity is deeply fissured, and each of the two apices is rugose. A few vertebrae of this genus have been preserved The relative propor- tions of the cervicals are unknown. The two venous foramina in the floor of the neural canal of the dorsals are very large. The caudals are long and stout. Restoration. — The Oxysenas had the characteristic peculiarities of the Creodonta and of the carnivorous Marsupials in their general proportions. The head was relatively larger, and the limbs were smaller than in true Carnivora. The feet were plantigrade, and had five toes anteriorly and posteriorly. The hind foot was either divided so that the external two 318 THE WASATCH FAUNA. toes opposed the internal three or the entire foot was directed outwards from the Hne of the calcaneuni. In the hitter case the hallux may have been opposable, as in the opossum, but in a much less degree. The tail was long and stout. Species of this genus were abundant during the Wasatch epoch in New Me.xico and Wyoming, and probably over the entire continent. Thev have not yet been reported from higher Eocene beds, not even occurring in the Wind River. A small species is found in the Puerco A species (0. r/aHice) has been recently detected in the Eocene of France by M. H. Filhol. This genus resembles Fterodon, as described and figured by Gervais, in the dentition of the maxillary bone; but the teeth of the lower jaw are totally distinct in character, approaching more nearly those of the Palceo- nyctis of De Blainville. According to Gervais, the inferior molars of Pterodon are like those of Hycenodon, without interior tubercle, and the inner lobes of the superior molars are not so large as in Oxycena. The latter differs from Palceonycfis in the character of the antepenultimate lower fnolar, which in Oxycena is characterized by the presence of a median blade, but in Palceonycfis by a heel supporting (in the typical species) two tubercles. OXYJE^A FORCIPATA Cope. Report Vert. Fose. New Mexico, 1874. p. 12. Report Capt. G. M. Wheoler, U. S. G. G. Expl. Surv. W. of 100th Mer., iv, ii, p. 105, 1877; pi. xxxv, xxxvi, xxxvii. Plate XXIV b, figs. 11-15; XXIV c, figs. 1-18. This formidable animal was abundant in Northern Wyoming during the Wasatch epoch. At least ten individuals are represented in the collec- tion from the Big Horn basin. The following are the dimensions of the mandibles of the five best preserved. Length of dental series Length of premolar series Depth of ramus at M. iii .. 1 2 3 4 .100 5 .103 T .100 .107 .042 .045 .044 .051 .054 .042 .039 .037 .042 .047 The measurement .035 for the length of the premolars given in my report to Captain Wheeler, loc. cit, refers to the anterior three teeth, which were originally supposed to be the only premolars. CREODONTA. 319 The specimen above noted as No. 2 presents a good many parts of the skeleton, from which I derive the following characters: M. Length of centrum of a dorsal vertebra 0^1 Length of centrum of a lumbar vertebra 025 Length of centrum of a caudal vertebra 027 Length of centrum of a caudal vertebra 030 The dorsals measui'ed are depressed artificially, but their length, is not apparently altered. The caudals are nearly perfect. Their neural arch is complete, but is relatively shorter on the shorter centrum than on the longer one; on the latter it has no spine. There are two transverse processes on each side separated by a notch. On the shorter vertebra they are nearer together, and the posterior is the larger. The inferior surface is regularly convex medially; at the extremities it presents two tuberosities, of which the anterior are the most prominent. The radio-carpal articular facet is short transversely. Surrounding it are four tuberosities. One of these forms the internal angle of the bone; the others are near the external end, one superior and one inferior; the fourth is at the superior side of the ulnar facet. Measurements of fore limb. Diameter of head of humerus from bicipital groove 023 Transverse width of condyles of humerus distittly 025 Anteroposterior of humerus at middle 013 Anteroposterior of humerus at external rim 021 vertical 013 Diameters of head of radius ^ c transverse 02U Diameters distal extremity of radius \ ^^^ ^ ' „, K transverse 024 Width of carpal facet of radius 016 Length of tuberosity of distal end of ulna - .008 Width of lateral tuberosity of distal end of ulna 016 Diameters cuneiform bone J ^^ " ( transverse Ulo Proximal width of first metacarpal (total) Oil Proximal width of second metacarpal (total) 0055 Proximal depth of second metacarpal (total) Oil Proximal width of fifth metacarpal (total) Oil The head of the tibia is characterized by the failure of the internal femoral facet to reach the posterior border. It thus leaves a free ledge. The anterior face of the distal extremity of the tibia is slightly con- cave. The malleolar process is large and truncate, and is not grooved, but rises into a low, wide tuberosity at the base. The fibular face is oblique to 320 TllK WASATCH lATNA. tlie anterior face, inclining to an angle of 40^. Its interior extremity is continued to a rather acute process, which is separated by an open notch from the btise of the malleolus. This carries the tendons of the flexor longus diil'donim and tibialis posticus muscles. The head of the fibula j)rojects con- siderably external to its tibial facet, the resulting section being ti'apezoidal, apj)roaching triangular. The posterior face of the head is gently concave and is surmounted by a low free rim. A ridge extending forwards from this gives the proximal end of the head a roof-shaped form. The posterior groove of the astragalus is wide. Its internal bounding angle is prominent, forming an oljliquely descending tuberosity. The ex- ternal bounding tuberosity is not so prominent. The anterior angle bound- ing the external calcaneal condyle is not more prominent, differing thus dis- tinctly from that of Mesonyx ossifragus. The lateral trochlear angles of the astragalus are obtuse, especially the internal. 'Jhe inner base of this bone has an open median notch. When the calcaneum is in position it is evident that the animal walked partly on its external side. This is bounded externally in front of the external condyle by a horizontal crest. The cu- boid facet only covers the external two-thirds of the distal extremity of the calcaneum. The internal third, however, retreats rapidly posteriorly in- wards. The very oblique calcaneal fac* of the cuboid, already described, is deeply notched externally by the proximal part of the groove for the flexor digitorum tendon. This groove forms a quarter of a circle, passing downwards, outwards, and backwards. The distal face of the cuboid is concave and is undivided. The entocuneiform facet of the navicular is situate more than its width away from the internal margin of the bone. The mesocuneiform is wide. The ectocuneiform is narrower than the latter, and bevels the external extremity of the navicular, thus looking towards the cuboid. Measurements of posterior limb. it. Dmmeters of proximal endof tibia 5 '■""' ""'' ''^' ^''"^ «■•««* ^^ I tnmsvorso 031 Diameters ofdistal end oftibia I '■"""'""•"'■' "1^ ( tr.'iiisvcrso 034 Foru and aft dianioti-r of proximal end of fibula 017 Total li-ngtli of a.stniKaliiH 0:S I ant(!ropoHt4;riur(;xtemaIly 0155 DNimctiTsiif irocIili'iK^ vt-rlioal externally 0145 ( trauBvereo 017 CREODONTA. 321 M. Width of bead of astragalus 016 Depth of head of astragalus (greatest) 009 Leugth of calcaneum externally 045 Length of fore part of calcaneum 018 Width of lore part at sustentaculum 021 Width of cuboid facet of sustentaculum 013 Depth of cuboid facet of sasteutaculnm 0008 Length of cuboid bone (greatest) 016 Leugth between calcaneal and metatarsal faces of cuboid on external side 007 Diameters astragalar face of cuboid ^■"'*'^™P°''t«"'"^ 010 ( transverse 0055 Diameters metatarsal face of cuboid \ anteroposterior 0095 ( transverse 0105 _. ^ „ . , < auteroposterior 013 Diameters of navicular < '^ t transverse 017 t longitudinal 030 Diameters metatarsus i ' < fore and aft 013' i proximal ; ^ (transverse 0105 ( longitudinal 040 Diameters metatarsus ii < ,< fore and aft 012 i proximal } ^ ( transverse 007 i longitudinal 044 Diameters metatarsus iii ^ . ,< fore and aft 012 f proximal > ^ < transverse 007 Diameters metatarsus ivproxiinallv < '"''^ '"'"' ^ ~ (transverse .. .009 Diameters metatarsus V proximally \ fore and aft 010 ( transverse 012 ( longitudinal 013 Diameters ungual phalange < , vertical 006 / proximal ) • ^ (transverse 006 Remarks. — From the above measurements, which are confirmed by more than one other skeleton, it can be seen that there is in this species a remarkable disproportion between the size of the skull and that of the limbs. While the dimensions of the jaws are like those of the jaguar, those of the limbs do not exceed those of the cheetah; while the digits are not only much shorter, as those of a plantigrade animal, but are more slender. The ungual phalange preserved shows that the claws had no prehensile power, and were not effective as weapons or for digging. This is a further indica- tion that the species of Oxi/cena were aquatic in their habits. PROTOPSALIS Cope. American Naturalist, 1880, p. 745; Bulletin U. S. Geol. Surv. Terrs., vi, 1881, p. 193. Inferior molars: one like those of Oxyoena, i. e., with large heel and internal cusp; another, probably the last, larger, without internal tubercle, and with a rudimental heel, thus resembling the inferior sectxjrial of various existing Carnivora. A median dorsal vertebra distinctly opisthocoelous. 21 c 322 THE BHIDGEK IWUNA. Femur with a weak tliird trochanter. The proximal extremity of fourth metatarsal of the right side furnishes instructive characters. The external side is deeply excavated below the cuboid facet, to receive a correspond- ingly prominent interlocking tuberosity of the fifth metatarsal. The exca- vation is nt)t divided by a longitudinal groove, as in the cats, but its surface extends continuously from front to rear. On the inner side of the fourth there is a subvertical facet for the tliird metatarsal, which is bounded pos- teriori}- by the usual deep vertical ligamentous groove. The foi-m of the true sectorial tootli, together with that of the meta- carpal, approximate this genus to the Felidu' more closely than to any other family of existing Carnivora. The resemblance seen in the sectorial is, however, probably delusive, as it is not the same tooth as the sectorial of the Cnniivora. The resemblance in the metacarpal is real, as the characters are unlike those of Canidce or Hi/tenidoi. It is probable that this genus should be placed in the Ox^a?H/c?oE between Plerodon and Oxyccna. But one species is yet known. Photopsalis tigrinus Cope. ^ American Naturalist, 1880, \i. 745; BuUotlu U. S. Geol. Surv. Terrs., vi, 1881, p. 193. Plate XXV 6, figs. 1-7. Size about that of the tiger or jaguai-, exceeding that of any other flesh-eater of the Eocene period. The heel of the smaller tubercular- sectorial is not large, and has a plano-concave superior surface. The prin- cipal cusp is much elevated, while the internal cusp is small. The sectorial (litters from that of a ////"//« in having the posterior cusj) more and the anterior cusp less elevated; the lieel is only a strong posterior cingulum, which is continued as a narrow line along the inner base of the tooth. A rough cutting ridge forms the posterior inner angle uf the principal cusp. There is a wide longitudinal groove of the inner face of the inferior canine, whose enamel surface is impressed-punctate. The inner side of the crown is so worn as to lead to the belief that the external incisor is of large size. The inferior border of the mandibular ramus rises below the last molar tooth. The masseteric fossa shallows gi'adually below, so that its inferior outline is not well defined. The dental foramen is of large size. The CREODONTA. 323 articular faces of a median dorsal are a little wider than deep, and the width is not equal to the length of the centrum. The outlines of the latter are gently concave, and it is not keeled below or on the sides. Surface smooth. The femur is preserved, lacking the distal extremity inclusive of the rotular groove. It is about as long as that of the jaguar, and is moder- ately slender. The head extends rather further proximally than the great trochanter, and is defined by a distinct neck. The fossa ligamenti teris is a wide posterior emargination of its edge. The great trochanter is recurved on its external border posteriorly, but the trochanteric fossa is open proxi- mally and fades out anteriorly and below. The little trochanter is large and has a long base. The third trochanter is a thickened angular concavity of the external border opposite a point a short distance below the little trochanter. The feet were evidently large; the proximal extremity of the fourth metatarsal is about equal in dimensions to that of a lion. Meastireme)its. M. • c anteroposterior 025 Diameters of crowu of sectorial < transverse 014 ( vertical 022 Length of heel of tubercular-sectorial OOC Width of s.ame 006 Vertical diameter of base of crowu of cauiue 022 Depth of mandible at last molar 044 Length of femur (condyles inferential) 310 Diameter of shaft at middle 034 Diameters of proximal extremity of fourth metatarsal } ^ < transverse 013 Length of ceutrimi of middle dorsal vertebra 027 Diameters anterior articular face of middle dorsal vertebrae '. " ( vertical Ulo 324 THE PUERCO FAUNA. MIOCL^NUS Cope. PaleoDtological Bulletin No. 33, p. 489, Sept. 30, 1881; Ibid., No. 34, p. 187, Feb. iO, 1882; Aioer. Nat. 18S1, p. 830, Sept. W; Proceed. Amer. Pbilos. Soc., 1881, p. 489; Loc. cii. 1883, p. 547. 1 ? 3 Dental formula; I. ?; C. r-, Pm. v ; ^I- k- First and second superior pre- 14 3 molars without internal lobe; fourth with one extemal cusp, and a more or less developed internal heel or cingulum; all the inferior premolars without internal cusp. Tiiie molars of superior series, with but one internal tubercle, connected by a low rid,. i ^■'""^'"I"'^""""'' ^"^ I transverse 0070 Diameters base M. jj U"««oposterior 0000 ( transverse 0(195 Mandible. Length of bases of liist fonr molars I>.i50 ,-,•„. 1, ( anteroiiosterior Olt70 Diameters P-m. iv / ' < t ransvcrse O0.t5 Diameteis M. ; > •'"teroposterior ,. . AXm ( transverse OOtiO T^. . _„ n ■•• $ anteroiiosterior OCW Diamrters M. in < ' ( transverse tKi43 Depth of nuuns at M. i 0115 Thiekneas of ramus at M. i 00*."> Another specimen includes the last four superior molars. The third true molar is even smaller than the corresponding inferior tooth would lead one to suppose, the grinding face having about one-lifth the superiicial area of that of the second superior molar. The fourth premolar has a little greater transverse diameter than the first true molar. In anotlRr specimen, which includes part of the skull with some superior molars, the third supe- rior nii)lar is a little larger tiiaii in the last mentioned, displaying one external and one internal tubercle In this specimen the second premolar has a .sub-triangular base with binadly mnnded angles, and the crown is .simple, with a conic apex. In tiir present species the characters c>f Mio- CREODONTA.. 327 clcenus are best seen in the subconical tubercles of the premolars, particu- lai'ly that of the heel of the fourth inferior premolar. In the other species this heel is more of a crest and is connected with the principal cusp by a low ridge. All the specimens of the Mioclcenus turgidus are from the Puerco beds of New Mexico, where they were found by Mr. D. Baldwin. MiOCLiENUS MINIMUS Cope. Paleontological Bulletin No. 35, 1882, ^. 468. Plate XXV e; figs. 22-24. This is one of the least mammalia of the Puerco fauna, exceeding by a little the Hyopsodm acolytus. It is represented by parts of two mandibles, which display all the true molars. The premolars are strictly those of Mioclcenus. The two anterior cusps of the true molars are higher tlian the heel, and they are united together to a point above the level of the heel. The section of both those of the !JI. ii is round; that of the external one of the first is crescentic; of the inner cusp, round. The heel is wide, and sup- ports a cusp at the posterior external angle. It is bounded posteriorly and on the inner side by a raised ridge, which gives with the cusp, on wearing, a comma-shaped surface. A transverse ridge closely appressed to the ante- rior cusps connects them anteiiorly. In one of the specimens there is a cingulum on the external side of the second inferior molar; on the other specimen it is wanting. Enamel smootli. The mandibular ramus is rather deep and compressed, and displays an external ridge on the anterior border of the coronoid, which is not con- tinued downwards. Meas u rem ents { l\''o, 2 ) . ir. Length of base of trne molais 0125 Diameter M.ii^''"t<^'^°P°«*«™^ ^'"-"^ ( transverse 0035 Depth of ram us at M. ii 0073 From the Puerco beds of New Mexico. D. Baldwin. 328 THE.PUERCO FAUNA. MlOCL^NUS BALDWINI Cope. American Naturalist, 1882, p. 853. (October, published Sept. 28.) PI.1t.- XXV f; fig. 16. Represented liv a ripht mandibular ramus which supports the last four molars, and contains the alveoli of the second and third premolars as well. The specimen shows that the premolars are large, the third the larg- est, and the second and fourth of equal length, and as long as the first true molar. The fourth jiremolar is oval in section and its heel is well devel- oped, and supports a median cusp. The internal posterior cusp of the true molars is well developed. The second true molar has a well-developed ante- rior inner cusp, which is wanting in Hemithlceus opistJiacus. The true molars grow successively narrower posteriorly, so that the last molar is relatively smaller than in H. opisthucus. The ramus becomes shallow anteriorly. It is also compressed throughout. The masseteric fossa is not marked, and the posterior part of the ramus is not incurved. The base of the coronoid pro- cess rises, so as to elevate the heel of the tliird inferior molar. Measurements. u. Length of last six inferior uiolars O-JS Length of last four inferior uiolars 022 Length of P-iu. iv O^'S" Length of M. i 0053 Leugth of M. iii 005.J Depth of ramus at M. ii 0100 De])th of ramus at Pui. ii 006o From the Puerco beds; discovered by Mr. D. Baldwin, to whom I have much pleasure in dedicating the species. Miocl.«;nus fekox Cope. Proceciliugs American Philosophical Society, 1883, p. 54*. Plate XXIV f; fig. 0 et »eq. This species is represented by four specimens. One of these includes various separate teeth and a considerable portion of the skeleton; a second includes loose teeth and a smaller number of bones of the skeleton; and the third consists of a part of a mandibular ramus, which contains the three true niolais. Those indicate the largest species of the genus yet known, the first individual above mentioned being about the size of a wolf CKEODOXTA. 329 The canines are well developed, and have a robust root. The crown is rather slender and is very acute. It is rounded in front, but has an acute angle posteriorh'. It is not grooved, and the enamel is smooth. The sin- gle-rooted first superior premolar is situated close to the canine, and behind it is a short diastema. I have the probable first true molar or fourth premo- lar. The external cusps are i-ather small, and are well separated from each other. The inner outline of the crown is rather broadly rounded. The internal tubercle is connected on wearing, with an anterior transverse crest which terminates near the inner base of the anterior external cusp, in an intermediate tubercle. There is a posterior intermediate tubercle. There is a cingulum all round the crown excepting at the posterior intermediate tubercle. The second (? first) true molar is like tlie one just described, but has relatively greater anteroposterior width. In this tooth the cingulum extends all the way round the crown. There are but two inferior molars of this individual preserved, the second and third true. The former of these has a parallelogrammic outline with rounded angles. There are two posterior, and two anterior tubercles; an anterior transverse ledge ; and a narrow external and posterior cingulum, the latter rising into the internal posterior tubercle. The latter is a mere angle and is much smaller than the external posterior, which has a wide crescentic section. Of the anterior tubercles the interior is much the larger, and has a circular worn base. The third true molar is triangular in outline. Its crown includes two anterior and an external median tubercle. The inner and posterior parts of the crown form a wide shelf, with the internal edge denticulate. A weak external cingulum. Measurements of Teeth. M. ^, . . , „ c ■ • I anteioiiosterior 0045 Duiuieteis base of crowu of lucisor) ' ) trausverse , 004 Diameters base crown of canine \ -luteroposterior 01;50 ( transverse 0095 ,, . ■ ,, . ( auteronosterior 0095 Diameters crown, snpcrior M. 1 ■; ' < trausverse 01"20 Diameters M.fii^""**'™!'"^^"''"^ ^^^^ ( transverse 0110 Diameters of inferior M. ii ^ '">*^''''I^"**t'^"°'' "1'^" ( trausverse 0105 Diameters of inferior M.iii^''"t'^■■''l"'*"^™'• 0125 ( trausverse 0090 330 THE PUERCO FAUNA. The second individual includes part of the superior walls of the skull. The fragment displays a high sagittal crest, which is fissured in front so as to keep the temporal ridges ai)art to near its anterior ai)ex. The brain sur- faces show small, smooth. Hat hemispheres, separated by a constriction fi< (in the wide and large olfactory lobes. The navicular bone shows three well- defined distal facets, indicating probably five digits in the pes. The teeth of this specimen include a posterior superior molar, and an infericM- thinl or fourth premolar, with other teeth. The premolar is like that of a creodont. Its principal cusp is a simple cone. To this is added a short wide heel, whose superior surface is in two parts, a higher and a lower, divided by a median ridge. A low anterior l)asal lobe, and a weak external cinguUun The third specimen belonged to an individual a little smaller than the other two. It includes the first inferior true molar, a titoth lust from the others. Its form is somewhat narrowed anteriorly, where it has two lnw, but well separated anterior inner tubercles, which form a V with the exterpal anterior. Specimen No. 1 is accompanied by fragments of vertebrae and limbs. The former are principally from the lumbar region, but fragments of the atlas remain. This vertebra is of moderate length, and the cutylus is some- what oblique. The vertebrarterial canal is rather elongate, and its anterior groove-like continuation in front of the diapophysis is not deeply excavated. The lumbar vertebra? are remarkable in the characters of their zygapo[)hyses. These display subcylindric surfaces of the posterior pair, which indicates that the anterior ones are involuted, as in the specialized Artiodactyles and Perissodactyles of the later geological ages. Such a structure does not exist among carnivora, nor in any mannnals of the Lower Eocene, to my knowledge, excepting some creodonta. I do not find it in Dklelphys nor Phascolarctos, but it exists in a moderately developed degree in Sarcophilus. It is, however, entirely similar to the airangement in Mesonyx obtusidens, which see. The articular surface forms more than half of a cylinder, and its sujte- rior portion is bounded within by an anteroposterior open groove. The surface within this is not revolute, as in Bos and Su~s, but the articular sur- face disaj)pears, as in Cervus. Eight such postzygajiophyses are preserved, all disconnected from their centra. Two of them are united together. There CREODONTA. 331 are two other separated zygapophyses of smaller size, which have but slightly convex surfaces. One is probably a prezygapophysis of a dorsal vertebra. No centrum is preserved. Of the anterior limb there is a probable distal half of a radius. It is of peculiar form, and resembles that of SarcophUns nrsinus more than any other species accessible to me. One peculiarity consists in the outward look of its carpal sui'face, which makes an angle of about 4 j^ with the long axis of the shaft. The obliquity in S. ursinus is less. The external border of the shaft in M. ferox is, however, straight, and terminates in a depressed tuber- osity. Beyond this, the border extends obliquely outwards to the carpal face, which it reaches at a right angle. The internal border of the shaft is gradually curved outwards to the external border of the carpal face. Its edge is obtuse, while the external one is more acute for a short distance, and rises to the anterior (superior) plane of the shaft. The carpal face is spherically subtriangular with rounded angles. It displays two slightly distinguished facets, one of which is superior, and the other is larger and surrounds it, except on the superior side. The internal marginal projection, or "styloid process," is not so prominent as in S. ursinus, and is a roughened raised margin. Joining it on the inferior edge of the carpal face is another rough projection of the margin. Immediately opposite this, on the superior edge of the carpal face, is a rough tuberosity, which incloses a small rough fossa, between itself and the styloid process. Internal to it is a shallow groove for an extensor tendon of the manus ; then a low short ridge, and internal to that a wide shallow depression for other extensors. The carpal face differs greatly from those of Sarcophilus and Dklelphys in having the inner portion wider than'the outer, instead of the reverse, and in having no distinct styloid process. It indicates that the manus was turned outwards much more decidedly than in those genera. I have described a bone very similar to this one in the Conoryctes comma, as the extremity of the tibia (p. ), which reference is probably erroneous. Of carpal bones the only recognizable one is the unciform. Its proxi- mal articular surface rises with a strong convexity entad, and descends to an edge ectad The metacarpal surface is concave in anteroposterior section, forming a wide shallow groove, extending in the direction of the width of 332 THE PUERCO FAUNA. the font. Its two metacarpal areas are not distinguished The entire first and second metacarpals, with the heads of the third and fourth, are pre- served. Thev considerably resemble those of Sarrojihilus vrsinuft. The distal articulations are injured in both, but both display a sharp trochlear keel j)osteriorly, which on the second extends nearly to the superior face of the articulation. The condyle is subround, and is constricted laterally, and at the base above. The second metacarpal is short and robust, shorter than in Sarcophihts ursinus. The first is also robust, but is relatively longer, as it is three-quarters the length of the second. Its head is expanded, espe- cially ])OSteriorly, and the large trapezial face is subtriangular, with round apex directed inwards as well as forward. The posterior face of the head i.s notched ectad to the middle. On the external side of the head there is a vertical facet with convex distal outline, for contact with the second metacarpal. The head of the latter is naiTOw, and is concave between the sides. The concavity is bounded posteriorly by a raised edge. The ante- rior part of the proximal facet is decur\x'(l. The shaft is deep proximally, but on the distal half is wider than deep. The lateral distal fossae are remarkably deep and narrow, the condyle very much contracted. The head of the supposed third matacarpal is as wide as the second anteriorly, but narrows to the posterior third, and then contracts abruptly to a narrow apex. The supposed external side of the head is perfectly straight, and is continuous with the side of the shaft without interruption. The entad side displays no facet, but has a depression below the head which adapts itself very well to the head of the first metacarpal. In fact, if the metacarpals just named second and third, exchange places, so that second is placed third and third second, the metacarpal series fits far better. The fourth fits the so-called second much better than the so-called third. This may therefore be the true order, altliough that first used agrees better with the carpus of ISurcophilus. The head of the so-called third is slightly convex anteroposteriorl}-, and is oblique laterally, descending a little to the inner side. The fourth metacarpal is wider anteriorly than either the second or third The inner edge is straight, while the outer is concave, the head being narrower l)efore than behind. It has a lateral facet on each side ; the inner plane, the external concave in the vertical as well as in the anteropos- CREODONTA. 333 tei"ioi' direction It thus approaches the form of a metatarsal, but is not so strongly excavated, nor is the head notched on either side. The unciform face is convex anteroposteriorly and plane transversely. The femur is broken up so that I cannot restore it. The head of the tibia is gone, but a considerable part of the astragalar face is preserved. This is transvei'se to the long axis of the tibia. It is narrowed anteroposteriorly next the fibular facet. Malleolus lost. The shaft is robust, and does not expand distally for articulation with the astragalus. Three centimeters proximal to the distal end, the external side thi-ows out a low, rough, i-idge- like tuberosity. Above the middle, the crest turns outwards, leaving the internal face convex. There is a broken patella, which has one facet much wider than the other. The astragalus has the trochlear portion a little oblique. That is, the internal crest is a little lower than the external, and the inner face is a little sloping. The latter is impressed by a fossa above the posterior part of the sustentacular facet, which runs out on the neck. The trochlea has a shallow groove which is nearer the external than the internal crest, and which passes entirely round the posterior aspect to the plane of the inferior face of the astragalus. The groove for the flexor tendon is thus entirely inclosed and issues on the inferior face at the posterior extremity of the groove which separates the sustentacular from the condylar facets. The external crest of the trochlea is less prominent posteriorly than the internal, thus reversing the relations of the superior part. The internal ridge becomes quite robust, but does not flatten out and project sub-horizontally as in Oxycena forcipata. The fibular face is vertical; neither its anterior nor posterior angles are pro- duced. The neck is somewhat contracted (the internal side is injured). The head is a transverse oval, strongly convex verticalh-, moderately so horizont- ally, and without flattening. A mesocune'iform (or possibly edocuneiform) bone is wedged-shaped in horizontal section, without posterior tuberosity,, and its anterior face is a slightly oblique square. The narrower facet is ob- lique in the transverse sense. The metatarsals are rejjresented, excepting the first and second. The only complete one is the fifth. The heads of the third and fourth are much like those of Oxycena forciputu, and of about the same size. Their anterior 334 TOE ITEKCO FAUNA. -width is equal, and in both the external side is more oblique than the inter- nal. Both have a notch at the middle of the internal side, but they differ in that the third has an open notch on the external side which is wantinj,'- ti> the fourth. The lateral excavations of the external sides are deep and rather large, and thin out the anterior external edge. The lateral facets are corresponding!}- large on the fourth and fifth; on the third metatarsal it is small, and a mere decurvature of the proximal surface. That of the fourth is loiigi-r proximo-distally thiiii transversely. That of the fifth is about as long as wide, and presents more anteriorly; or, to express it more accurately, the shaft and head present more outwardly than those of the fourth. The jiroximal, or cuboid facet is narrow anteroposteriorly, and is curved, the external side being concave. On the external side just distal to this facet the head of the Ijone expands into a large outward-looking tuberosity, which is separated from the posterior tuberosity by a strong notch. Between it and the head projier, on the anterior face, is a large fossa. The entire form is something like that of the proximal extremity of a femur with head, neck, great trochanter and trochanteric fossa. A some- what similar form is seen in the corresponding bone of Oxi/cena forcipata. The shaft of the fifth metatarsal is one-fifth longer than that of the second metacarpal (? 3d) above described. Its direction is straight, but it is some- what curved anteroposteriorly. Its section is subtriangular, the apex external. The condyle is narrowed and subglobular above, and spreads lateral!}' behind, the external expansion being wide and more oblique. T|ie keel is prominent, and is only visible from above (in front) as an angle. The distal extremities of some other metatarsals diff"er in being flatter at the epicondyles and concave Ijetween them on the posterior face. The con- dyles are more symmetrical, and are bounded above on the anterior face by a jjrofound transverse groove. Several phalanges are preserved, including part of an unguis. They are all depressed, nm! with well-marked articular sur- faces, of which the distal are well grooved, and the proximal notched below. The lateral areas of insertion of the tendons of the flexors are well marked on the edges of tlie po.sterior faces. An ungual phalange is much com- pressed at the base. The basal table is well marked, and has a free lateral edge. The nutritive foranuMi enters above- the posterior extremity of this edge. No trace of basal sheath. CREODO>'TA. 335 Measurements of Ko. 1. M. l^eiigth of atlas at anterior vertebrarterial foramen 01G5 Expanse of postzygapophyses of a lumbar vertebra 0230 Diameter radius at midille of shaft 0100 Greatest distal width of radius 02'20 ( verticil 0140 Diameters carpal surface ? " ( transverse OlSo . vertical (interiorly) , 0130 Diameters of unciform ■? anteroposterior (greatest) 0140 ' trausverse (in front) 0150 ,,. ^ , , . ,.< anteroposterior OloO i)iameters head metacarpal 1 { ^ ^,^„ < trausverse UrJU Length of metacarpal i 0310 AVidth metacarpal i at epicoudyles 0110 Diameters head metacarpal ii^'^"'^^''P°^f«"'"^ "^^^ I transverse 0070 Length of metacarpal ii (or iii) 0400 AVidth of metacarjial at epicoudyles 0120 ,,. ^ , 1 .-». •••- ■•,< anteroposterior 0125 Diameters head ot M. iiHor II) ^ '^ ( transverse ()U/ o T^- . ^ 1 e \r ■ i anteroposterior 0120 Diameters head ot M. iv^ ^ . , ,, , „„-„ (transverse (at middle) 00/0 Width of patella near middle 0190 Diameters of tibia .07 M. Irom astragalus \ .i-^teroposterior 01«5 ( transverse Ol.io Anteroposterior width of astragalar face 0200 Total length of astragalus 0310 t length on groove 0210 Diameters of the trochlea^ width above 0160 ( elevation externally 0130 Greatest width of astragulus below 0225 Length anterior to internal crest of trochlea 0100 ^. , J J- » i , . . < auteroposterior 0130 Diameters head of metatarsal 111 < '■ ,. ^ ,, „,./> ( transverse (lu iront) 01 lU , , ,. ^ ^ ,. < anteroposterior 0140 Diameters head ot metatarsal IV ' ' ( trausverse 0105 f t anteroposterior OICO I without tuberosity ^ r ^yith lateral facet 0080 Diameters head M. v j ( """^n erse ^ ^.^j^^^^^ j^^^j.^^ ^^^^^ ^,^,jq I, transverse over all 0170 Length Mt. v 0400 Width Mt. V at epicoudyles 0120 AVidth Mt. V at condyle above 00t)5 AA'idth of il. iii or iv at epicoudyles 0120 AVidth of proximal end of phalange 012 Length of smaller phalange (1st series) 0230 „ . , ,. ^ ,. ,, , , (vertical 0070 Proximal diameter ot smaller phalange ^ (transverse OHO Ungual phalange, vertical diameter of cotylus 0090 The specimen Avhicli lias l)een partially described in the preceding- pages ^s No. 2 has many pieces which are identical Avith those preserved in speci- men No. 1. Among these may be mentioned the glenoid cavities of the 336 THE ruEKco fau:ma, squamosal bone. These display, besides the larg^e postglenoid process, a well-dev'eloped preglenoid ridge, as in Arctocyonoidce, Oxi/aiiida, and Meso- nychklee. A huge distal caudal vertebra of elongate t'orni indicates a long tail. An articular extremity of a flat bone is intermediate in form between the proximal end of the marsupial bone of Dklelphys and that of Sarcophi- lus. Its j)rincipal and transverse articular surface is transversely convex, as in the latter {S. ursinus), but the lesser articular face is separated from it by an even shorter concave interspace than in the opossum. It has almost exactly the form (.it middle) "103 niilUHtrr, hr.idofo.mam./mJ"""""'""'^ """!" f antcropcxiterior (KKV* Diaimt.-n. cuneiform J '■'•'•"''"' '^^^ < anttTopoHterior 01 1* CREODOXTA. 337 I vertical in front 0085 Diameters navicular/ transverse 0180 ( anteroposterior (middle) 0110 ( vertical at middle 0100 Diameters entocuneiform < anteroposterior (middle) 0140 ' transverse distally 0060 Two other bones of specimen No. 2 I cannot positively determine. The first resembles somewhat the trapezium of Sacrophilus ursinus, and still more that of Didclphys. I will figure it, as a description without identifica- tion will be incomprehensible. The next bone is of very anomalous foi'm. It may be the magnum, which is the only unrecognized bone of importance remaining, or it may be a large intermedium. It has no resemblance to the magnum of any mammal known to me. It was evidently wedged between several bones, as it has eight articular facets. Two are on one side; the largest (convex and oval) is on one edge; three are on one end, and two, the least marked, are on the other flat side, opposite to the first. Restoration. — We can now read the nature of the primitive mammal Mioclcenus ferox, in so far as the materials above discussed permit. It was a powerful flesh-eater, and probably an eater of other things than flesh. It had a long tail and well-developed limbs. It had five toes all around, and the great or first toe was not opposable to the others, and may have been rudimental. The feet were plantigrade and the claws prehensile. The fore feet were well turned outwards. There were in all probability mar- supial bones, but whether there was a pouch or not cannot be determined. These ppints, in connection with the absence of inflection of the angle of the lower jaw, render it probable that the nearest living ally of the Mioclce- nus ferox is the Thylacynus cynocephalus of Tasmania. The presence of a patella distinguishes it from Marsupials in general. Its dentition, glenoid cavity of the skull, and other characters, place it near the Arctocyonidce. Should the forms included in that family be found to possess marsupial bones, they must probably be removed from the Creodonki and placed in the Marsupialia. This species is about the size of a sheep. The bones are stated by Mr. Baldwin, who discovered it, to be derived fiom the red beds in the upper part of the Puerco series. 22 c 338 THE PUERCO FAUNA. MiOCLAENUS SUBTRIGOKUS Cope. Paleontological Bulletin, No. 33, p. 491. Proced. Amer. Philos. Soc, 1881, p. 4'Jl; 1B83, p. 555. Plate XXIV f, fig. 4; LVIIf, fig. 5. This species was originally represented by a portion of a cranium an- terior to the orbits and lacking the extremity of the muzzle, distorted by pressure. It exhibits nearly all of the molar teeth. The species differs from M. targidus in the greater acuteness of all its cusps, and in the equi- lateral form of the fourth premolar. It is too large to belong to the M. minimtis, which is represented by mandibles only; and too small to be the M. mandihularis, whose maxillary dentition is unknown. The inner borders of the molar teeth are shorter than the outer, espe- cially in the last two molars. The last true molar is smaller than either of the others. The cusps are all subconical, but the internal is connected with the intermediate by ridges, which give it a triangular section. The latter form a V, homologous with that in AnisoncliMS, but not so distinct, and the intermediate tubercles are not lost in its branches as in that genus. The posterior inner lobe of that and other genera is represented by a thicken- ing of the cingulum. This cingulum extends entirely round the P-m. iv and M. i, and M. ii; the M. iii is injured. The sides of the base of the base of the P-m. iv are slightly concave. The enamel of all the molars is wrinkled. Measurements. u. Length of baees of last five molars 0285 Diametere of base of P-m. j,. 5 ant^^opo^tMior (XMH) ( transverse 00.50 Diameters of base of M. i J ''"^"''P"^*"'"^ • 0^ (transverse 0000 Diameters of base of M. ii 1 "°"='°P»«t"'°' *'*'" c transverse 0075 DiameteiB of base of M. ju 5 anteroposterior 0040 ( Ininsverse (KXiO I now give the characters of the inferior molar series, which have been found, by Mr. Baldwin, associated with the true superior molars. Of the latter, it may be remarked that the second true molar is not so much longer than the first as in M. hucculentus, although the diflPerence in size is very evident. The third is smaller than the first, and ovoid in outline, while the first and second are subquadrate. The external cusps are conic and widely CREODONTA. 339 separated, and the intermediate areas are distinct. There is a cingulum all round the crown of the last two, and round that of the first, except at the 'inner side, and at the anteroexternal angle. The last three inferior premolars are higher than long at the base, and are compressed, and the apex acute. The posterior edge of the third and fourth is truncate, and simple. Each has a posterior cingulum which forms a narrow heel on the fourth. No other cingula. Of the true molars only the second is wanting. The form of these is like those of the M- ferox, with the cusps more prominent. The first only has trace of the anterior V; in the others, the two anterior tubercles ai'e opposite and connected by a short anterior ledge. The heel of the first consists of a basin bounded by three tubercles, of which the external is pyramidal and largest. The median posterior is small. The heel of the third is narrow and prominent, and the internal lateral tubercle is represented by a short raised edge. The enamel of all the molars is wrinkled, and the inner side of the premolars is grooved with the height of the crown A weak external cingulum on M. iii. Measurements. M. Length of last three superior molars 0265 Diameters of M.i I ^"t'^^P^^t^""' °°^ < transverse UUbO _. . „ ,, ..(anteroposterior 0062 Diameters of M. n{ ' .„_- ( transverse Wli _. „ ,, ..< anteroposterior 0047 Diameters of M. lu < '^ „„„,, ( transverse uubO Length of last inferior molars - - -0340 Length of last three premolars 0140 Length of P-m. iv 0050 Elevation of P-m. iv 0050 _. , „ ,, .(anteroposterior 00.57 Diameters ot M. i < , ,^.„ ( transverse - - uu4>• hransver^e OOGO The structure of the second inferior molar places this species between the M. turffidus and the M. hrachysiomus. It is as large as the former, but had larger jaws and muzzle, judging by the size of the premolar tooth. From the Puerco Beds of New Mexico, D. Baldwin. MiOCLyENUS PROTOGONIOIDES Cope. American Naturalist, 18*2, p. 833, (October, published Sept. 28). Plate XXV f, fig. 17. The third in size of the genus, represented by the superior true molars. It is an exaggerated form of the M. suhtrlgonus. The internal angle of the V, as well as the intermediate tubercles at the ends of its limbs, are distinct. Cingula extending entirely arountl the crown, the posterior with a small tubercle on the M. ii as in A. subtrigoitits ; none on M. iii, which i.s .7.") the area of the M. ii. Diameters M. ii, anteroposterior, .008; trans- verse, .010. Diameters M. iii, anteroposterior, .007; transverse, .009. From the Lowest Puerco of New Mexico, D. Baldwin. CREODONTA. 341 MlOCL^NUS BUCCULENTUS Cope. Proceedings American Pliiosophical Society, 1883, p. 555. Plate XXIV g; fig. '2. A part of the right maxillary bone which supports three molars indi- cates this species. The molars are Pm. iv, M. i and M. ii. This series is characterized by the remarkably small size of the fourth premolar, and large size of the second true molar. The first true molar is intermediate. The fourth premolar consists of an external cone and much smaller internal one. There is a weak posterior basal cingulum. The reduced size of the internal cone suggests the probability that the third premolar has no internal cusp, and that there may be but three premolars. In the latter ■case the species must be distinguished from Miodcenus. The first and second true molars have conic well separated external cusps, and a single pyramidal internal cusp. The intermediate tubercles are distinct. There is a posterior cingulum which terminates interiorly in a flat prominence. There is an anterior cingulum and a strong external one, which form a pi'ominence at the anterior external angle of the crown. En- amel wrinkled. Mtasttrements of Superior Molars. M. Lenglli of bases of Pm. iv, M. i .and ii 0180 5 anteroposterior 0040 diameters Pm. iv ^ ^ransyerse 0046 ) anteroposterior 0060 Diameters of M. i transverse 0065 < anteroposterior 0070 Diameter of M. ii ^ t^^^^^erse 0085 From the Puerco region of New Mexico, D. Baldwin. MlOCL^NUS CORRUGATUS CopC. Paleoutological Bulletin No. 30, p. 560, 1883. Plato XXIV g ; fig. 1. This species is known from a right maxillary bone which contains the last four molar teeth, with parts of pelvis and other bones of one individual. This species is intermediate in size between the M. protogonioides and M.ferox (see p. 3'25). The superior molars are more nearly quadrate than in the other species of the genus, owing to the better development of the posterior internal tubercle, which is, however, as in the others, a mere thickening of the posterior cingulum. It is wanting from the last superior molar. H Diameters M. i < ' < trausverso... 342 THE BKIDGER FAUNA. Tlie cusps on the true molars are, as in the M.ferox, small, and not large and closely placed as in M. protogonioides. The intermediate ones are nearly obsolete. The crowns are all entirely surrounded by a cingnlum. The entire enamel surfaces wrinkled so as to be rugose, although the teeth are those of an adult and well used. The second superior molar is larger than the first, exceeding it in the transverse rather than tlie fore-and-aft diameter. The third is the smallest, and is of oval form with obliquely truncate external face. It is less reduced than in the M. turgidus. The fourth premolar consi.sts of a strong compressed-conic cusp with three basal cusps of small size, viz., an anterior, a posterior, and an internal. The last is the larger, though small ; is formed like a heel, and is connected with the others by a cingulum. No external cingulum. MeaMirementn. M. Length of last lour molars 036 Diamete™P-m.iv^''"''>^"P°«'"''"" "1" transveiM! 008 rior 010 -• 010 ■^, . ,, ... (anteroposterior 008 Diameters M. iii { ^ ( trausverse Oil From the Upper Puerco beds; D. Baldwin. ACHiENODON Cope. Paleontological Bulletin, No. 17, \>. 2, Oct. 25, 1873. U. S. Gcol. Surv. Terrs. Auu. Rep. for 1873, p. 457. Known from the skull only. Dentition: I. ; C. -; Pm. .; M. - ^ ;',' i' 4 3 Canines well developed ; dental series without diastema First superior premolar two-rooted ; crown of second (third) compressed, simple. Crown of third (fourth) with one external and one internal principal tubercles. Su- perior molars quadritubercular. First inferior premolar one-rooted. Crowns of third and fourth compressed, simple. First and second true molars quadritubercular; of third true molar with five lobes, the posterior one forming a heel. Symphysis not coiissified. This genus agrees witli other AniocyonidoB in the presence of a preglenoid crest. Its relationships to the other genera of the family appear to be quite clo.se It is not yet absolutely certain whether there are four or three in- ferior j>rem<)lars. In case the latter is the correct number, the first pre- molar is two-rooted. CREODONTA. 343 It is probable that this genus, in common with the other ArctocijonidcE, stands in ancestral relation to the existing families of the arctoid carnivora. It is, in the restriction of its premolar series, rather less primitive than Ardocyon, and prepares the way for the Procyonidce, the least specialized of the true Carnivora. From this family, by a modification of the fourth pre- molar towards a cai'nassial form, we derive the extinct genus Hycenarctos Falc. of the upper Miocene, and the existing Aeluropoda M. Edw. From the latter the bears have doubtless been derived by a process of divergence from the general carnivorous line, in a special direction of their own. Although the Arctoids are well represented in America, an Eocene ancestor has hitherto been a desideratum. It is now happily supplied. But one species is known from North America. It is a large and formidable animal. ACH^NODON INSOLENS Cope. Paleontological Bulletin, No. 17, p. 2, Oct. 25, 1873. Ann. Kep. U. S. Geol. Surv. Terrs. 1873, p. 457, Jour. Acad., Phila., 1874., Fig. 5, p. 10, March. Plates LVII and LVII a. • The only specimens of this species which I possess consist of mandib- ular rami. The Princeton Exploring Expedition of 1877 discovered a good skull with lower jaw, at the same localit}', and the director of the museum of Princeton College, Professor Guj^ot, kindly permitted me to examine it. I am under obligations to him and to Professors Scott and Osborne for the means of ascertaining the characters of the cranium and superior molar teeth above given. Perhaps before the present article appears, their memoir on this species will have been published. I confine myself to the general characters given, and direct my readers for fuller details to their monograph. Judging from the size of the size of the skull, this species was about as large as a lion. It had a muzzle of about the length characteristic of that animal, and a huge sagittal crest. The eyes were remarkably small. The rami are robust and rather shallow. The external face is but little convex below the last premolar, but projects much beyond the alveolar border opposite the last two molars. The anterior border of the masseteric fossa is quite prominent, but the fossa shallows out below. The inferior outline of the ramus is gently convex. The symphysis is rather long and rises at an angle of 45°. Its posterior termination is opposite the middle 344 THE BRLDGER FAUNA. of the third premohir. There are two mental foramina, one under the second and one under the fourth premolars. The incisor teeth present forwards. The tubercles of the true molars form two pairs, the third with a large fifth lobe. These paired lobes are more or less united at the base, while the pairs themselves are well separated from each other. The anterior pair is a little more elevated than the posterior pair. Last premolar with longer basis than first molar ; its posterior heel tubercularly plicate. The crown of the penultimate premolar is a slightly compressed simple cone with elon- gate base, but little shorter than that of the first molar. Molars with smooth enamel ; an anterior cinguluni on the second and third. A small posterior median tubercle on the second molar, and a short external cingulum from the base of the posterior cone forwards, on the third. Canines very large, sub-erect, enamel smooth. Length of molar scries 1^ Diameter of canine tooth 0.J3 Length of premolars 093 Length of premoliir No. 3 035 Length of molar No. 1 024 Length of molar No. 2 027 Width of molar No. 1 - 022 Length of molar No. 3 041 Width of molar No. 3 024 Depth of ramus at molar No. 2 073 The type specimen was found by Mr. Samuel Smith at the mammoth Buttes near the head of South Bitter Creek. The formation is the "Washa- kie basin of the Bridger. The Achoeiwdon insolens shares with the Protop- salis tigrinm and Mesonyx ossifragus the distinction of being the largest of the Eocene flesh-eaters. It was a formidable beast, and a worthy associate of the large Palceosyops vallidens and huge Dinocerata of the same period and region. DISSACUS Cope. American Naturalist, 1881, p. 1019 (November 29). This genus is only known from upper and lower jaws. These possess a dentition much like that of Mesonyx, which diflers, however, from it in one essential respect. The apices or cusps of the last two molars are double, not simple as is the case in Mesonyx. This constitutes an apjiroach to Sarro- thrauste^, where there are three apices to the main cusp. Two species are kiHiwn, both from the beds of the Piu'rco Epoch. CREODONTA. 345 DissAcus NAVAJOviDS Cope. American Naturalist, 1881, p. 1019. Mesonyx navajoviits Cope, Proceed. Amer. Philos. Soc. 1881, p. 484 (September 30). Plate XXV c; iig. 1. Smaller than the two known species of" Mesonyx, and with the crowns of the molars more compressed and the blades of the heels of the inferior series more acute. Molars seven, the first one-rooted. Last molar with a cutting heel like the others, and with the penultimate, with a rudimental anterior inner cusp. All the molars with an anterior basal tubercle except the first, second, and third. No basal cingula. Principal cusp elevated and compressed, as in the premolars of Oxycena. Enamel minutely rugose. Mandibular rami and inferior canine teeth compressed, the angle of the lat- ter not inflected. Measurements. u. Length of inferior molar series 078 Length of premolar series 046 Length of base iv premolar 010 Pm. iv, elevation of cusp 008 Length of ii true molar .012 Elevation of true molar 010 Width of heel of true molar 005 Depth of ramus at M. ii 020 Diameter of base of crown of canine 009 This species was a little larger than the red fox. Its remains were found by Mr. D. Baldwin in Northwestern New Mexico. DiSSACUS CARNIFEX Cope. American Naturalist, 1882, p. 834 (October 5). Plate XXIV g; figs. 3-4. This creodont diff"ers from its only congener in its greater size, and in the presence of an anterior basal lobe on the third inferior premolar. This is wanting in D. navajovius. As compared with the latter the six inferior molars are as long as its seven, and the mandibular ramus is much deeper. Like it the Pm. iv and the true molars have an anterior basal tubercle; and the last two true molars have an internal supplementary cusp. After the Sarcothraustes antiquus, the largest flesh-eater of the Puerco, and about equai in dimensions to the coyote. 346 THE PUERCO FAUNA. Measurements. u. Length of last sis molars 075 length of true molars 038 Ixiigthof Pin. iv 012o Loiigth of M. ii..., 013:> Lcnttthof M. iii 0130 Depth (if ramus at M. ii 029 Northwestern New Mexico; D. Baldwin. SARCOTHRAUSTES Cope. Palcontological Bulletin, No. 34, p. 193, February 20th, 1882 ; Proceed. Am. Phil. Sec, 1881, p. 193. We have in evidence of the characters of this genus the last two superior molars, the last one lacking the crown; and parts of both man- diljular rami, which exhibit teeth as far posteriorly as the first true molar inclusive; all belonging to one individual. A part of a skeleton of a second individual, which includes a fragment of lower jaw, belongs prob- ably to this species. Sarcothraustes resembles both Amhlydonus and Mesonyx, but it is prob- ably to the latter genus that it is allied. The last superior molar is trans- verse, much as in Oxycena. Tlie crown of the penultimate is subtriangular and transverse. It has two external subconic cusps and a single internal lobe, whose section on wearing is a V, each branch of the face extending to the base of the corresponding external tubercle. There are three small inferior incisors, and a large canine. There are probably only three inferior premolars, the first one rooted. The crown of the second has no heel The crown of the third has a short wide heel. The crown of the first true molar consists of an anterior elevated cone and a posterior heel. The latter is wide, having a posterior transverse, as well as a longitudinal median keel. The fragments of the supposed second individual include two large glenoid cavities with strong preglenoid crests, as in Mesonyx. As compared with Mesonyx, this genus differs in the V-shaped crest of the penultimate superior molar; in Mesonyx it is represented by a simple cone. The last superior molar of Mesonyx is triangular and not transverse, but the composition of the crown of that tooth in Sarcothramtes must bo known before the value of this character can be ascertained. If the view that Sarcothraustes has but three inferior premolars be correct, this character distinguishes it from Mesonyx, as do also the transversely expanded heels of the molars. CEEODONTA. 347 Sarcothraustes ANTiQuus Cope. Loc. sup. cit. Plate XXIV e; figs. 19-22. The penultimate superior molar has a strong posterior cingulum which commences within the line of the internal bases of the external cusps, and rises into considerable importance behind the internal cusp. There is also an anterior cingulum which does not rise internally, and which is continuous with a strong external basal cingulum. The latter passes round the pos- terior base of the posterior cone, and runs into the posterior branch of the internal V. The posterior cone is smaller than the anterior cone, and its apex is well separated from the latter. The appearance of this tooth is something like that of a carnivorous marsupial. The symphysis mandibuli slopes obliquely forwards, and is vmited by coarse suture. The ramus is stout and deep, as compared with the size of the molar teeth. The roots of the teeth are relatively large, especially those of the first two premolars. The crown of the canine is lost. The first premolar points forwards, nearly parallel with the canine, and divergent from the second premolar. The crown of the second premolar is small and subconic, and has a rudimental heel, and no anterior basal tubercle. The first true molar resembles considerably that of Mesonyx. There is a small anterior basal tubercle on the inner side of the principal cusp. The ex- pansion of the heel is transverse only, there being no longitudinal lateral edges or tubercles. The enamel is obsoletely, rather coarsely wrinkled. There are two rather large mental foramina; the posterior below the ante- rior root of the first true molar, and the anterior below the posterior root of the second premolar. Measurements. M. \ auteroposterior externally 01.5 Diameters of superior M. ii. ^rausverse ! ' 024 Anteroposterior diameter of base of M. iii 0095 Auteroposterior diameter base of crown of inferior canine 020 Length of bases of three inferior premolars 038 f anteroposterior 019 Diameters inferior M. i. < transverse 0095 ( vertical OHO Depth of ramus at Pm. iii 01520 Width " " 022 348 THE WASATCH AJsD BIflDGEK FAHNJS. MESONYX Cope. Paleontological Bullotin No. 1, p. 1, July ^J, 187a. Proceed. Auicr. Pliilos. Soc, 1872, p. 460. Ibid., 1873, p. 198. Tlio Flat-C'liin-e. Proceed. Aiii.r. I'liiloa. Soe., 1872, p. 48:1. Flat-Clawed Caruivora, etc., p. 5, plates I and 2. Proceed. Amer. Pliilos. Soc., 1873, p. 203. Annual Report U. S. Geog. Geol. Surv. Terrs., Hayden, 1872 (187:t), pp. 550, ."VVJ, plates 5, 6. This genus is known from the dentition of the lower jaw and part of that of the upper, and from many parts of the skeleton. The superior molar teeth are yet unknown. Of the known parts of the skeleton the anterior limbs are derived from the M. lanius, while the vertebrae and poste- rior limbs are those of the M. obtmidens. As I have hitherto placed these species in different genera, I must explain my reasons for uniting them in Mesonyx. The two species were obtained from different localities, the M. lanius from the Washakie, and the M. obtusidens from the Bridger basins. It is not certain that these beds belong to exactly the same horizon. Through the kindness of Professor Guyot, I have been able to examine the lower jaw and teeth, with some other portions, of a species related to M. lanius, if not the same, from the Bridger basin. Tliis specimen contains the molar teeth characteristic of M. obtusidens ; the corresponding ones being worn down by attrition in the type specimen of M. lanius. 3 1 4 ? Dentition : I. = ; C. - ; Pm. - ; M. ~. The space between the inferior canines is so narrow that it is probable that the incisors were wanting or reduced in number. The external superior incisor conical and larger than the others. Superior canines vertical; inferior canines subhorizontal. First inferior premolar one-rooted. Premolars from the third similar to the molars, consisting of a posterior median blade, an anteromedian conic cusp, and an anterior basal tubercle. The true molars diminish in size pos- teriorly, but their composition is identical with that of the first, so far as determinable. The cranium of the M. lanius is fractured above. There remain the squamosal and periotic bones, occiptal condyles, malar and part of maxillary, both premaxillaries and the greater part of both mandibular rami Tlio squamosal process of the zygoma is produced inferiorly far below the audi- tory meatus, even further than in the bears. Itspro.ximal portion includes, CEEODONTA. 349 on the lower face, a strong glenoid groove at right angles to the axis of the cranium, with its anterior margins acute and prominent. This is the well- defined glenoid cavity of the feline type. The zygoma has a wide curva- ture, indicating a powerful temporal muscle. The posterior angle of the malar extends well posteriorly. Its anterior portion projects, forming a longitudinal rib ; there is no produced postorbital process. The tympanic bone is produced upwards and outwards and forms a tube with everted lips. The opisthotic (mastoid) separates it entirely from the exoccipital, and over- laps the posterior half of the tube by a laminar expansion. A pit in this bone near the meatus externus represents the insertion of the stylohyal ligament. There is no bulla, the tympanic chamber being small, with thick walls and without any trace of septa. The character of this region resembles that seen in the bears more than that of an}- other carnivorous type. The premaxillaries are vertico-oblique in position, presenting the nai-eal opening directly forwards as in cats, but with a still less prominent alveolar border. The horizontal part of this box-der is indeed very short, including but two small incisors. It then rises vertically, and turns obliquely back- wards to the maxillary, inclosing a deep sinus with the canine tooth. From the anterior side of this sinus the larger external incisor issues, with its root extensively exposed externally. A rib ascends from the front of its alveolus to the anterior or nareal margin of the bone. The triturating surfaces of the incisors are directed backwards, and the alveolar edge is thickened in front of them with a tuberosity. The teeth are much worn so that the forms of the crowns cannot be determined, but at .25 inch beyond the alveoli they are compressed, the large outer tooth with a longitudinal angle in front. The cranium of the specimen of M. obtusidens is fragmentary. The malar bone of the right side is similar in position and form to that of the CanidcE, especially in the presence of a weak angle onl}-, to mark the pos- terior border of the orbit. It has a much less expanded union with the maxillary than in these animals, and is proximally shallower, thicker, and more prominent. Its posterior portion is more plate-like. The cervical vertehrce of the M. obtusidens are damaged. The dorsals are strikingly smaller than the lumbars, being less than half their bulk. They 350 THE WASATCH AND BRIDGER FAUN^. are opistlioccelous with shallow cups, and the centra are quite concave laterally and inferiorly. The centra of the lunibars are more truncate, with a trace of the opisthocojlous structure, and are quite depressed in form. The median part of the series is more elongate than in the corresponding vertebrfe of the genus Canis. They exhibit an obtuse median longitudinal angle, on each side of which, at a little distance, a nutritious artery entered by a foramen. The zygapophyses of the posterior lumbars have inter- locking articulations, the posterior with a convex exterior articular face, the anterior with a concave interior one. The sacrum is not completely pre- served; three coossified centra remain. These are more elongate, and the diapophyses have less expansion than in Fells, Hycena, Cants, or TJrsus. They are much flattened, and the middle one has two slight median longi- tudinal angles. The caudal vertebrae indicate a long tail, with stout base. Its proximal vertebrae are depressed, and with broad, anteriorly directed diapophyses The more distal vertebrae have subcylindric centra ; the ter- minal ones are very small. The bones of the fore limbs of the M lanius are stout in their propor- tions. The humerus has a well-mai'ked rugose line for muscular insertion on its posterior face, but no prominent angle. Distally the inner and outer condylar tuberosities are almost wanting, and there is neither external ali- form ridge nor internal arterial foramen. The olecranar and coronoid fossae ai'e confluent, forming a very large supracondylar foramen. The condyles are moderately constricted medially, and there is a well-marked submedian rilj separated from the outer condyle by a constriction. The latter is con- tinued as an acute ridge on the outer side of the olecranar fossa. The inner condyle is the more prominent, and its outer margin is a sharp elevated crest. The ulna has a very prominent superior process, continuing the cotylus upwards. The coronoid process, on the other hand, is rather low. The radial cotylus is flat and broad. The distal end is not preserved. The radius has a more transverse head than Canis or Felis, and has three articu- lar planes, the inner being a wide oblique truncation of the edge. The shaft is angulate below, and becomes a little deeper than wide near the distal end. The extremity is lost. The carpal bones are probably all jirescnt The fore foot was found in place so that the relations of the bones are CREODONTA. 351 known with certainty. (Plate xxix a, fig. 1.) Tlie scaphoid and kinar are distinct. The former exhibits proximally the inner tuberosity, then a shght concavity, and then the convexity for the radius, and then it is obhquely truncated so as to give a general rhomboid outline. Beneath there are but two facets, the inner for the magnum the deepest, and divided lengthwise by the truncation of the bone. The larger facet fits correctly the 0.0. trapezium and trapezoides. The lunar preserved, lacks the posterior extremity. It has a short anterior or external face, and a very convex proximal one, with a subquadrate cross-section at its greatest convexity, whicli is near its mid- dle Below it presents the usual two facets, the one more concave than the other, and soon cutting off the latter, meeting the internal facet behind it. The upper face is convex. The cuneiform is large and concave length- wise above, for the narrow extremity of the ulna. Below, it has a large concave facet for the unciform. The pisiform is of unusual size, and is as stout as the largest metacai'pus, and nearly half as long as the outer (5th) metacarpal. It articulates with a thick V-shaped facet of the cuneiform. Its extremity is obtuse and expanded. The trapezium is large and is attached to its metacarpus laterally, sending a process downwards poste- riorly. It supports a narrow articular surface for a rudimental first meta- carpus, which is not preserved, but which could not have been larger than that of the spotted hyena. The trapezoid is smaller and of a triangular out- line, with the base forwards. The magnum is a rather small bone, articula- ting as usual with the metatarsals 2 and H. It is depressed in front. The unciform is a large bone with a considerable external anterior surface. Two-thirds of its upper surface is in contact with the cuneiform, the remaining part projecting upwards with convex face to unite with the lunare. Below, it supports metatarsals 4 and 5. There were probably four digits of the fore foot, the pollex being very rudimental. The propoitions are stouter than in the dogs and hyenas, but not so much so as in the bears. The proximal extremities of the metacar- pals interlock as in the hyenas, and much more than in the dogs. The external side of each is excavated to receive an oblique facet of the one adjoining, as in Protopsalis ; but there is no abrupt prominence as in tlie cats. The phalanges have a length similar to that seen in some bears, 352 THE WASATCH AND BRIDGER FAUN^. bat the metatarsals are more elongate. The lengths of the latter are, fifth shortest, then second, third, and fourth. Their condyles are broad, with median keel behind, and shallow supracondylar fossa in front. The first phalanges are about one-third the length of the metacarpals; the second of digit No. 2 broad and stout, and half as long as the phalange of the first row. An ungual phalange has a singular form, so that the claw might be supposed to have a subungulate character. It is flat, consider- ably broader than high and with expanded and obtuse extremity. The articular extremity is depressed and transverse concave in vertical, convex in transverse section. The anterior three-fifths of the superior middle line is occupied by a deep gaping fissure, which separates the extremity into two points. The inferior face is entirely flat, there being no tendinous tuberosity. The sides are grooved, and give entrance each to a large arterial foramen proximally. These claws i-esemble remotely those of seals, and differ remarkably from those of existing terrestrial Carnivora. The glenoid cavity of the scapula of ilT. obtusidens is shallow; the coracoid process is a short hook, separated by a strong groove from the edge of the cup. The spine is well developed. In the character of the coracoid, this genus resembles Felis more than Canis or Ursus. The ulna exhibits little trace of articular face for the I'adius, less than in Felis or Canis. Its humeral glenoid face ii;j more convex transversely in its anterior or vertical portion, than in those genera, and a little more than in Ursus. Of the hinder limb of the M. lanius, the only characteristic pieces remaining are the navicular, cuboid, and an external cuneiform bone. The cuboid is rather stout, with a slightly concave proximal facet and two distal ones, one of them smaller and sublateral. The navicular is wide and flat, and with a strongly concave astragaline facet. Below, it presents two deep oblique concave facets for the cuneiforms, with a small sublateral one on the outer side. The facets of the cuboid indicate that the fourth digit is well- developed, but the presence of the hallux cannot be positively ascertained. In the hind liml) of the M. obtusidens the femur resembles that of true Carnivora in all essentials. The rotular groove is narrow and elevated, the inner margin a little higher. The condyles are rather nairow, the inner with less transverse and anteroposterior extent, and separated by a wide CREODONTA. 353 and deep fossa. The patella is narrow, thick, and truncate at one end. The proximal end of the tiUa exhibits a very prominent and well elevated crest or spine, which bounds a deeply excavated fossa. The articular faces are separated by a deep notch behind; the external is a little the larger and is produced into a point outwards and backwards ; it lacks the notch of the anteroexterior margin so distinct in Canis, but possesses an emargination at the outer base of the crest, homologous with it. The general form is, however, more like that of Canis than of Fells, and least like that of Ursiis. The distal extremity of the tibia presents Carnivorous characters. The two trochlear fosses are deeply impressed, the outer wall of the external one being formed by the fibula only. The anterior marginal crest is more ele- vated than the ijosterior, and presents an overlapping articular face between the fossaj for a corresponding tuberosity of the neck of the astragalus. The inner malleolus is entirely without the groove for the tendon of the tihialis posUciis muscle, and therefore different from many of the digitigrade Carnivora. It has an ovate truncate surface. On the anterior face opposite the inner trochlear groove is a rather small but deep fossa. The astragalus has an elongate oblique neck and a navicular extremity slightly expanded inwai-ds. The trochlear ridges are well elevated, and not very oblique to the true vertical plane, being much as in the dog. The dis- tal extremity is quite different from Felts, Hycena, Canis, and Ursus in having a rather naiTow convex facet next the cuboid bone extending from front to rear, and in having the navicular facet puUej-like or slightly concave in transverse section, while it is strongly convex anteroposteriorly. This is part of the peculiarity presented by the hind foot in this genus Behind the navicular facet, on the superior face, is a tuberosity which stops the flexure of the foot by contact with the tibia; a trace of it is seen in the dog. The calcaneum has the compressed form of the digitigrades, but the broader internal, and convex external astragaline facets resemble much more those in the bears. The sustentacular facet looks as much forwards as upwards. The cuboid facet is a frustum of a triangle with the apex directed inwards and downwards. The metapodial bones are rather elongate, and flattened so as to be transverse in position. A second metatarsal is more flattened than corre- 23 c 354 THE WASATCH AND BRIDGER FAHN^^. spending bones of Cants and Felis. Its cuneiform facet is somewhat concave transversely. It has two facets for the third metatarsal, as in Hycena; that is, they are a good deal more distinct than in Felis, where they are more distinct than in Canis. The distal condyles are furnished with a posterior and inferior carina, which is wanting above; the articular face is wide above as in Canis, and is bounded by a transverse fossa as in digitigrade genera. The phalanges of the first series are elongate and curved as in Felis, being relatively longer than in Ursus. Phalanges of the other series are qnite short. The ungues are short and flattened, their inferior surface is nearly plane, and the superior but little convex. A shallow groove divides the upper face longitudinally to the extremity. The margin below is acute to a slightly contracted neck. There is no indication of collar for reception of the horny sheath, except perhaps a slight area of fracture on each side, and there is no projecting tuberosity below for insertion of flexor tendon. The middle of the proximal part of the unguis is a raised plane, and on each side of it, at the neck, two arterial foramina enter. There is a small foramen in the groove, and several smaller ones near the margin. These ungues i-esenible somewhat those of some tortoises. They were found with the other phalanges, with which they agree in size and articulation, and no doubt belong to the same animal. It is evident that they differ in character from those of most existing Carnivora. The penultimate phalanges agree with ihem in the depressed form of their proximal articular faces, wanting entirely the trian- gular form so characteristic of Carnivora, especially of the cats and dogs. The short flat shaft of the same is almost equally peculiar. It is clear that there were only four anterior digits in M. lanius, and but four posterior ones in M. ohtusidens. Affinities. These have been already considered in their general beai'ings. The genus is the type of a distinct family, which must be placed nearest to the Amhhjctonidce. From this family the MesonychidcB differ in the complete trochlear articulation of the ankle-joint. At first sight Mesonyx appears to have some similarity to Ilycenodon in its dentition, but close examination shows that the resemblance is rather to Amhlyctonus. There is no true sectorial blade on any tooth of Mesonyx, the long heel furnishing the only cutting edge, as in the premolars of several genera. As in Uycenodou there CEEODONTA. 355 is no internal tubercle, it is true, but the median tubercle is a cone, and the anterior is rudimental, so that there is no sectorial structure. The structure of the feet in Hycenodon being yet unknown, it is not possible to state the relations seen in these parts. The hind feet ai'e, as already pointed out, entirely different from those of other Creodonta, to which group the fore feet refer the genus. The flat claws are a unique peculiarity, and suggest affinity to the seals, and an aquatic habit. The teeth, moreover, show a tendency in the same direction, in the simplicity of their crowns. The structure of the ankle forbids the supposition that these animals were exclusively aquatic, as it is of the type of the most perfect terrestrial ani- mals. The reduced number of digits — four both anterio)"ly and posteri- orly— as in the Hycenidoe, is also opposed to any suggestion of aquatic habits. Species. Two are certainly known, and a third may be in our collec- tions. The former are distinguished as follows, by the dentition of the lower jaw : Smaller in aU dimensions, except in the first true molar, which is equal that of M. lanius M. obtusidena. Larger by one-half, except in the first true molar, which equals that of the other species M. laniua The specimen in the Princeton museum, already mentioned, is of simi- lar form and proportions to the M. lanius, excepting that the last two inferior true molai-s are only four-fifths as long as those of the S. lanius. History. I have been unable to find any reference to this genus othei than those included in the citations at the head of this article. Mesonyx obtusidens Cope. Proceediugs American Philosopliical Society, 1872, 480 (July 29), et loc. Bup. cit. Plate xxvi, figs. 3-12; xxvii, figs. 1-24. Of the typical specimen of this species, there are preserved portions of the skull with teeth, chiefly mandibular ; numerous vertebrae from all parts of the column ; parts of scapula, ulna, and fore feet, portions of pelvis, femora, tibiae, tarsals, metatarsals, and phalanges. There are numerous teeth preserved, but separate from the skull and mostly mandibular. The inferior canine is stout, especially in the root, 356 TUE WASATCU AND IJltlDGEK rAUN.E. which is a flat oval in section. The crown is but Httle curved, shghtly compressed, and without edge or groove. The premohirs graduate into the mohirs, so that the hue of distinction is not easily drawn. The first premolar has a single root : the crown is slightly conic, with a small tubercle at the base behind. Thi.s tubercle increases in size on the premolars 2 and 3, and becomes on the true molars a longitudinal cutting edge extending along the axis of the crown, not much elevated above a wide base. It occupies half the length of the crown in the larger molars, and is preceded by an elevated conic cusp. In front of the base of this, a small conic tubercle projects forwards, which appeared as a rudiment on the third premolar. • I'he num- ber of mandibular teeth wouhl appear to be, Pm. 4, M. 3. No portions certainly referable to the superior molars were found. There are no cingula on the teeth, and the enamel is perfectly smooth. The appearance of the crowns as well as of the bones indicates an adult animal. The measurements are as follows : Length of m.ilar bono 073 De]>tli of malar bone in front 016 Depth of malar bone at postorbital angle 0"2:? Depth of malar bone at niidtlle of orbit 015 Tliickni'ss of malar bone at middle of orbit 013 Length of crown of canine tooth (worn) '. 020 Diameter of base fore and aft 013 Diameter of premolar (1) fore and aft 006 Length of crown of pri-niolar 006 Length of biisc of premolar (2) Oil Height of crown of premolar 009 Length of crown of triu? molar 018 Width of crown of true molar OOS Height of cutting edge 005 The internal face of the trochlear portion of the astragalus is nearly plane, not oblique, as in most of the Crvodonta. The external side is a little more inclined, especially opposite the anterior extremity of the trochlea, where the inferior portion is produced into a horizontal process. The head is not expanded tran.sversely, the internal tuberosity l)eing very low, and the infero-extemal side concave. The sustentacular facet is small and iso- lated. There are no horizontal processes of the distal extremity of the calcaneum as are commonly seen in Creodont genera. The inferior face of the calcaneum is concave in cioas-section for its distal half The second CREODONTA. 357 metatarsal has its cuneiform surface convex anteroposteriorly and concave transversely. There is a small proximal facet looking inwards at the front of the inner side of the pi-incipal facet, apparently for the entocuneiform bone. There is a well marked ligamentous insertion on the anterior face of the shaft next to the facets. The carina of the posterior side of the condyle of several of the metapodial bones is continued for a shoi-t distance on the posterior face of the shaft : Transverse diameter of glenoid cavity of scapula 0-,'5 Transverse diameter of ulnar cavity for himierus OH Length of centrum dorsal vertebra 019 Diameter of centrum, transverse 014 Diameter of centrum, vortical 014 Length of centrum of a median lumbar 030 Diameter of centrum, transverse 025 Diameter of centrum, vertical 01b Diameter of centrmu vertical, first sacral 014 Diameter of centrum transverse, first sacral 026 Expanse of sacrum "46 Length of two sacral vertebrce 049 Length of proximal caudal 02'« Expanse of diapopbyses caudal - 03b Diameter of centrum caudal, vertical 009 Diameter of centrum caudal, transverse 015 Diameter of centrum distal caudal, vertical 007 Diameter of centrum distal caudal, transverse 007 Chord of femoral trochlea and condyles 038 Width of trochlear groove 013 Width of condyles ^'■^^ Width of tibia, proximally 038 Diameter of tibia, anteroposteriorly 039 Diameter of shaft, .050 M. from end 017 Diameter of distal extremity, transversely 026 Diameter of distal extremity, anteroposteriorly 018 Length of patella 025 Width of patella ''15 Length of astragalus 030 Width of astragalus above Olfa Width of astragalus distally 017 Widt h of astragalus, neck 012 Width of cuboid facet of calcaueum 016 Depth of cuboid facet of calcaueum Oil Width of a second metatarsal (shaft), 012 Depth of a second metatarsal (head) 014 Width of a second metatarsal distal end 010 Length of proximal phalange 0290 Width proximally 0100 Width jiroximally of a penultimate iihalange 0085 Length proximally of a penultimate phalange OHO Length of ungual phalange 0150 Width medially 0065 Width proximally 0070 358 IHE WASATCn AND BRIDGER FAUNJ3. Besides tlie inferior size, this species apparently differs from the M. lanius in the form of the ungual phalanges. Those preserved are much nar- rower than the single one of the M. lanius that is known. It is, however, not certain that these phalanges were alike on all the digits. This species was as large as a wolf. While the proportions of the limbs were not very different, the foi'm was rather more slender behind. The orbit was smaller, and the cheek bone more prominent than in those animals. The long tail added to the general resemblance to the dogs. The narrow navicular facet of the astragalus renders it probable that the inner toe is wanting or rudimental, and that there are four digits on the hind foot. The claws are flat, and altogether without prehensile use, but rather adapted for aquatic life. I obtained the bones above described on a bluff of Cottonwood Creek, near Fort Bridger, Wyoming, during my expedition of 1872. All the pieces were found in close juxtaposition, and without admixture of those of any other animal. Mesonyx lanius Cope. Synoplotiicrium lanius Coi)C. Paleontological Bulletin No. 0, p. 1, August 20, 1872. Proceed. Amer. Pliilos. Soc, 1872, p. 483. Ibid., lS7:t, p. 207. Annual Report U. .S. Geol. Surv. Terrs., 1672, p. 5o7, pis. 5-(j. Plate xsvii, fig. 25; Plates xxviii, sxis, figs. 1-6; Plate xsis.a, fig. 1. Besides the typical and, so far, the only specimen I have obtained of this species, there is a second probably referable to it in the museum of Princeton College. For the opportunity of examining the latter I am in- debted to the kindness of Professor Guyot. My own specimen is repre- sented by a large part of the skull with nearly complete dentition, the superior molars loose; lumbar and caudal vertebra;; large portions of both fore limbs, including the bones of the feet; smaller portions of the hind limbs and feet. The mandibular rami are quite elongate, and indicate a cranium near the size of that of the brown bear ( Ursus arctos). Their form is slender, and they have a long, rather narrow, symphysis, which projects obliquely forwards. The angle is not preserved. The mental foramen is large and issues just behind the canine teeth. The dentition is I. 5-r; C. r; M- -;:,■ The canine is of very laree size. 10 17 J s> r CREODONTA. 359 especially the part pi-otruded beyond the alveolus. The crown is stout at the base, but is soon compressed and obliquely truncated by the attrition of the inferior canine on its inner face. Two superior molars preserved are three-rooted, and the section of the crown is more or less equally trilobate. The number in the maxillary bone is estimated at seven, the number found in the ramus of the mandible. There are six two-rooted molars below, and probably one single-rooted premolar, though this is indicated by an alveolus only. The molars are rather narrow anteroposteriorly, and are not very different in size, except that the penultimate is a little longer, and the last a little shorter than the others. There was evidently a longitudinal cutting- edge behind, and some other shorter process on the front of the ci'own ; the edge is preserved on the last tooth and resembles that of M. obtusidens, so that I have little doubt that the remainder of the tooth was, as in that genus, a conic tubercle. This opinion, based on my imperfect specimen, is shown to be correct by the Princeton specimen. Here the teeth are as in M. obtusidens. The most remarkable feature of the genus is seen in the inferior canines. These are very large teeth, and are directed immediately forwards, as in the case of the cutting- teeth of rodents. They work with their extremities against the retrorse crowns of the two external incisors above, and laterally against the superior canine. They are separated by a space about equal to the diameter of one of them. In this space I find no alveoli nor roots of teeth; the outer alveolar wall extends far beyond the inner. The latter terminates opposite the middle of the superior canine. It may be that there are no inferior incisors. Some of the vertebrae display stout triangular neural spines ; on the lumbars the posterior zj'gapophyses are embraced laterally by the grooved correspondents of the succeeding vertebra. Some of the caudal vertebrae are long, slender, and without neural arch, indicating that this genus, like 3£. obtusidens, had a long, slender tail. Measurements. M. Length of glenoid cavity 045 Width of glenoid cavity 025 Diameter of zygomatic fossa 05S Width of opisthotio inside foramen stylohyoideum 01 i Diameter of meatus auditorius extemua 012 Diameter of cavum tympani 009 360 THK WASATCn AND BRIDGEB FAUN^. H. LoDg.b of ramus mandibuli jirt'scrved i'iS LeiijjrU of sRTics of sovcn molar teeth 1^1 Lenjjth of last molar, crown 0155 Width of last molar, erowii OOSO Leujjth of ]>eniiltimati-, tTown 0215 Width of poiiultimato, crown 010 Length of fxiro.sed jiart of inferior canine 024 Length of I'xposed part of superior canine 032 Length of exposed part of outer upper iucisor 023 DiauietiT of triturating-surfacc inferior raninc 028 Diameter of trituratiug-surfaee inferior canine, transverse 01G6 Diametrr of superior canine, anteroposterior 024 Diameter of the two inner incisors 010 Diameter of exterior iucisor, oblique 010 Diameter of symphysis mandibuli 044 Diameter of uare.al oritice . 040 Depth of uareal orilice 031 Depth of mandibular ramus at M. 6 049 Thickness below of mandibular ramus at M. 6 014 Length of a superior molar, crown 020 Diameter of condyl- of humerus 047 Diameter of shaft of humerus, cimipresscd 0410 Diameter of <'ondyles of luunerus 0415 Diameter of condyles of humcnis, anteroposterior 032 Diameter of head of radius, transverse 0282 Diameter of head of radius, vertical 0162 Diameter of shaft of radius 016 Diameter of cotylus of ulna, long 030 Depth of ulna at coronoid process 034 Length of carpus and digit 2 without unguis 112 Length of two jdial.anges willumt unguis 037 Length of metacarpal without unguis 061 Length of metacarpal No. 3 974 Length of metacarpal Xo. 4 070 Length of metacarpal No. 5 .'.. . . 053 Length of .scaphoid, tran.svcrscly 023 Length of cuneiform, transversely 027 Length of jiisiform, transversely 027 ■Width of pisiform, distally 016 Length of luiciform, transversely 020 Width of unciform, auteroiio.stcriorly 013 Width of tr.-ipezoid, anieroposteriorly 0155 Widtli of trapezium, auteropo.steriorly .0114 Length of trapezium, vertically 016 Width of .s(^nplioid, aut<'roposteriorly 015 Width of navicular, auteroposteriorly 0155 Length of navicular, transversely 0255 Length of ungual phalange 016 Width of ungual phalange 010 Diameter of centrum of lumbar vertebra 029 Diameter of centrum oi caudal vertebra 009 Restoration. Tlie fore feet are like tlio.se of both dog's and liears. The very prominent ])ostglenoid ridge, and the narrow tympanic chamber CUEODOXTA. 3(51 are decided ^joints of resemblance to the bears, but the cavum tympani is even less expanded than in those animals. The characters of dentition are more like those of the HycEnodontidce and Amhhjctofiichc than any other group, and even the remarkable incisor-like inferior canines are approxi- mated by the anteriorly directed canines of Hycenodon leptorliyndms Laiz. et Par. The Mesonyx lanius was considerably larger than the If. obtusidens, equjling the black bear (Urtius americanus) in size. It had a large head, with a long, rather narrow, and truncate muzzle. The limbs were relatively smaller, not exceeding those of the black bear in length and thickness. The tail was long and slender as in the cats, while the claws were broad and flat as in the beaver. Habits. The molar, cani>ie, and incisor teeth of my specimen, as well as that of the Princeton fossil, are. much worn by use. This is especially true of the canines of both, while the crowns of the molars of the Bitter Creek specimen are almost entirely worn away. The same peculiarity is to be observed in the specimens of the allied Amhlyctonus sinosus, which I obtained in New Mexico.* It is probable that these species chewed hard substances. The peculiar approach of the lower canines is a special modifi- cation for peculiar habits, which I suspect to have been the devouring of the turtles which so abounded on land and in the waters of the same period. The slender symphysis could most readily be introduced into the shell, while the lateral pressure of the upper canines with the lower, would be well adapted for breaking the bony covering of those reptiles. The breaking of these shells in the attempt to masticate their contents would produce the unusual wear of the teeth observed. History. I originally placed this species in a genus distinct from the M. ohtusidcns on the ground of a supposed difference in the number of molar teeth. The Princeton specimen renders it extremely probable that the two species are congeneric. The dental series is uninterrupted from the canine if, as I believe, there is an alveolus for a simple premolar behind it. This I overlooked *Sec Report of Lieut. G. M. AVheeler, Expl. Siirv. W. of 100th Mer., 1 v., irt. ii, PI. xxxiii, figs. 1-3 and 11. 362 THE WASATCH FAUNA. when first describing the species, and hence gave the molars as 6 instead of 7. The typical specimen was found by myself on a terrace of the Mam- moth Buttes, near South Bitter Creek, Wyoming, in the beds of the Wash- akie basin. A portion of the bones had fallen a few feet from a remaining mass of the softer bed, where I soon found the rest of the specimen in place. The skull and anterior foot were taken out from close juxtaposition. Mesonyx ossifragus Cope. Plates XXVIII a, Fig. 1 ; XXVIII b; XXVm c; XXVIII d ; f XXIV e, figs. 14-19. American N.atnralist, 1881, p. 1019, December. Proceedings Am. Philos. Soc, December, 1881, p. 165. Pachtiana ossi/raga Cope, Report Vert. Fossils New Mexico, U. S. Geog. Snrv. W. of 100th Mer., p. 13, 1874. Id., Ann. Report Chief of Engineers, 1874. Report Lieut. Wheeler, p. 12.">. Report Capt. Wlieclor, U. S. G. G. Surv. W. of 100th Mer. iv, ii, p. 94, 1877, pi. .xxxix, fig. 10. I was so fortunate as to receive from Mr. Wortman the greater part of a skull of this species, together with some bones of the limbs, belonging to one individual. These were mingled in great confusion with tlie bones of two individuals of PJienacados, which I was able to distinguish through the fortunate possession of a complete skeleton of the P. primcevus. Besides this individual, Mr. Wortman obtained jaws and some of the bones of three individuals from the Big Horn basin. M. ossifragus was the largest Creodont of the Eocene, equaling the largest grizzly bear in the size of its skull. In a cranium with lower jaw and almost complete dentition, the length to the preraaxillary border from the postglenoid crest is M. .365 ; the largest Ursus horribilis in my collec- tion gives .270 for the same length. This specimen has the dental formula I. -; C. ; P-m. -; M. -. The claws have the flattened form which I dis- 2 1 4 3 covered in 3£. lanins, and the proximal phalanges have much the shape of those of a Perissodactyle. Tlie astraglus has much the character of the animals of that order, and has the distal facets as I originally detected them in the M. obtusidens The form of this bone is shorter and wider than in the latter species. The skull already mentioned lacks the brain case and basicranial axis, embracing the muzzle, zygomata, pterygoid region, and lower jaw, with CEEODONTA. 363 nearly complete dentition. The muzzle is contracted and is rather short ; the zygomata are widely expanded. The pi-emaxillary extends well poste- riorly along the nasal, but it does not probably reach the frontal bone, which is lost from the specimen. The maxillary is contracted behind tlie canines. The molars arise from it in a ridge which commences above the fourth premolar. The free part of the bone presents an angle downwards just beyond the maxillary, and posterior to this point has a thin inferior border without the bevel indicating the insertion of the masseter muscle usual in carnivora. The maxillary projects posteriorly in a free angle sep- arated from the base of the pterygoid process. The posterior extremity of the molar is a little anterior to the glenoid cavity, and has a horizontal internal expansion The superior border of the bone has a very slight postorbital angle. The glenoid cavity is wide and deep. Both the preglenoid and postglenoid crests are large, and are most elevated externally. The meatus auditorius externus is small, and is closed below by the posttympanic pro- cess without visible tympanic bone. The posttympanic is not coossiiied with the postglenoid process, but is in contact with it. Just interior to tlie meatus the posterior face of the former becomes somewhat tuberous. It has a free superior border, which for a short distance forms the posterior boi'der of the zygomatic fossa. I do not see postglenoid or postzygomatic foramina. The mandible is distinguished for its long and slender rami and sym- physis. The inferior border is gentl3^ convex, and the symphyseal portion is in the line of the remaining part of the rami. The length of the sym- physis is unusual, being one-third of the total to the base of the condyle. Its inferior face is distinctly separated from the lateral face by an obtuse angle. The condyle projects much beyond the angle, and is quite large. Its face looks upwards and backwards. The angle is shallow and little prom- inent, its posterior border extending obliquely forwards. Its thin interior edge is directed somewhat obliquely inwards, though not distinctly inflected. The base of the coronoid process is very wide, equaling the length of the inferior molar series, omitting the first premolar. Its anterior border slopes obliquely backwards, and is obtusely rounded to the summit. The latter is not elevated and is very obtuse. The posterior border descends obliquely 364 THE WASATCH FAUNA, and then nearly vertically to the base of the neck of the condyle. The masseteric fossa is not defined either anteriorly or inferiorly. The superior incisors are slender, and the crowns are very short and acuminate. The e.xternal incisor, though the largest, is not so large abso- lutely or relatively as in the smaller species Mcsofii/x laniu'^: The precauiue diastema large, equaling that posterior to the first superior premolar. The canines are very large and have an oval section at the base lying anteropos- teriorly. The crown is destitute of ridges, and the enamel is perfectly smooth. The first premolar has one root with an oval section. The two roots of the second are large in comparison with the crown. The latter has no anterior basal lobe, has a simple cone, and a heel with cutting median edge. The cone has no edges or ridges. The third premolar has the .same form, with the addition of a rudimental anterior basal tubercle. The heel has a wide base. The fourth premolar differs from the third in having a large internal conic lobe and an anterior basal tubercle. The pos- terior edge of the principal or external cone carries a small lobe ; its ante- rior face is rounded. On the first and second true molars this small lobe becomes a second external cone smaller than the anterior external and than the internal cone, which are about equal. Botli these teeth have an ante- rior and posterior basal lobes The second true molar differs from the first, in that the posterior basal lobe is smaller, and that the external cingulum into which it continues is wider than that of the first true molar. It also extends with an interruption to the anterior basal lobe of the second molar, but is rudimental on the anterior external jjart of the first. The outline of the bases of both of these teeth is trifoliate, the anterior external lobe a little the smallest. The posterior molar is more nearly triangular, the external part of the crown having less anteroposterior extent. It supports one external cone witli a small posterior basal lobe, and a posterior, external, and anterior cingulum. The internal cone is well develoi)ed, but is not so large as the external. None of the molars have an internal cingulum. Tlie crowns of the inferior incisors arc lost, but their bases are small. The canines are large, and have an anteroposterior oval section without angles or grooves. Enamel smooth. The first premolar is one-rooted, and is directed very obliquely forwards. Tlie second and third jMcir.olars are CEEODONTA. ■ 3(35 like the corresponding superior teetli, except that the lieel of the tlhrd i.s not so wide, and the median edge is more prominent. The remaining four molars are alike. They consist of a principal conic lobe with a small anterior basal lobe and a large posterior heel. The cone has a low median anterior edge, and more prominent median posterior edge. The lieel has an obtuse cutting edge, which rises in a compressed trihedral form, as it is truncated behind as well as flattened at the sides. No cingula on the inferior molars. Enamel obsoletely rugulose. Measurements of cranium. Length from i)remaxilLiry border to postglenoid . :i6o Length from premaxiUary border to eud of last molar 193 Length of dental series, including canine and last molar 166 Width of premaxiUary teeth on bases :045 W^idth between bases of canine teeth 0.')1 Width at convexities of zygomata 282 Width of glenoid cavity ^♦'•'"'"^'■^'■^'''y ^^ t fore and aft 034 Depth of zygoma posteriorly 077 Depth of molar at middle 048 Diameters of base of canine I ''°*^'~''r''«t^"°'^ 025 t transverse 020 Length of series of true molars 057 Length of base of P-m. li 0125 Diameters p.m. iv^'*°**™P''«terior 019 ( transverse 015 Diameters M.i^''°*^™P°^f^"<"' ^'-'15 ( transverse 018 Diameters M.ii^''"t*^°P''«t"*'"- 0205 ( transverse 0205 Diameters M.iii^'»"t'''"''P°^t«'"'"- 015 c transverse 017 Length of mandibular ramus 302 Length of mandibular ramus to posterior base of coronoid , 322 Length of mandibular ramus to anterior base of coronoid 190 Length of mandibular ramus to end of symphysis 112 Depth of ramus at P-m. 1 047 Depth of ramus at M. iii 068 Depth of ramus at coronoid process 122 Depth of ramus at neck of condyle 025 I vertical ". 014 Diameters P-m. iii/ anteroposterior 017 ( transverse behind 009 I vertical 015 Diameters P-m. iv ^ anteroposterior 020 ( transverse 010 { vertical 015 Diameters M. iii^ anteroposterior ^ .022 ( transverse Oil 366 THE WASATCH FAUNA. Two posterior dorsal vertebrae display a number of peculianties. They are moderately elongate, and moderately depressed. They have a strong median inferior angular ridge and concave sides. The articular faces are oblique and slightly opisthocoelous. There is a longitudinal lateral ridge, and a second lateral ridge above it which is continued into a short anapophysis. The external edge of the prezygapophysis is also produced backwards as a ridge, but terminates abruptly at the middle of the side of the neural arch. The postzygapophysis presents a free angle outwards. The base of the neural spine is compressed, and extends over the whole neural arch. The peculiarity of these vertebrje as compared with the corresponding ones of Canis and Feblis, is the absence of the metapoph}'ses, and the conse- quent horizontal spread of the postzygapophyses. The inferior keels and oblique opisthocoelous centra are not found in those genera. They are in fact something like cervicals, but the absence of vertebrarterial canal and presence of anapophysis, foi'bids such reference. The fore-limbs of this individual are represented by both humeri, ulnae and radii, and by the lunar, cuneiform and magnum, with four or five met- acarpals of one side. Both humeri are a little distorted; one is abnormally shortened, and the other is elongated proximally. The peculiarit}- of this bone is its shortness, as compared with the bones of the fore-arm and of the posterior leg. The great tuberosity is prominent, and the deltoid crest extends far down on the shaft, terminating only a little above the radial fossa. The external epicondyle is not prominent, and is marked by shallow fossae. The ridge which forms the external edge of the posterior face of the distal part of the humerus is prominent, but disappears before reaching the epicondyle. The internal epicondyle is very prominent, and rises into a ridge which bridges over the supracondylar foramen. The olecranar fossa is wide and deep. The condyle consists of the internal flange and the external cylinder. The former is not very prominent nor acute; the latter is rather short transversely, and is a little convex in the transverse section. Its anterior face is shorter tiian its posterior face, and the latter has a low external raised border. This humerus resembles considerably that of the M. lauius, from which the internal epicond^'Ie and foramen have been lost CEEODONTA. 367 I have also probably restored the length of the shaft (Plate XIX, Fg. 1 ; so as to be too long. The radius and ulna are rather stout and are moderately decurved. They present many peculiarities. The inner edge of the ulna is raised so as to be in contact with the radius throughout its length. The external edge of the shaft of the ulna is also elevated nearly its entire length, thus inclosing a wide deep groove with the external edge. This external ridge is the origin of the supinator brevis muscle, and of the extensores pollicis in mammalia, and would appear to indicate unusual power of supination of the hand, and of extension of the thumb. But the form of the head of the radius forbids the idea that that bone could be rotated so as to supinate the hand to much extent. The olecranon is long, and is deep near the coronoid process, and contracts towards its extremity. The coronoid process is elevated and unusually wide, the sides extending upwards so as to be nearly parallel, forming a truncate instead of the usual acuminate summit. The facet band for the radius is slightly concave. The humeral face rises above it on a pi'ocess of the inner side. Immediately anterior to it a nar- row and rather deep fossa extends along the inner superior edge of the ulna, opening onto the general surface of the shaft within a short distance. The interno-inferior face of the shaft of the ulna is convex. The distal extrem- ity is acuminate; its inferior face is flat and is bounded by a ridge with a tuberosity externally. A convexity and then a concavity of the internal surface adapt it to the radius. The carpal extremity projects beyond that of the radius, and is quite narrow in both directions. It has not the double- rib head-like form of that of Oxycena. The radius is rather stout. The head is transverse and deeper at the internal than the external side. The humeral surface is double ; one part is concave and occupies the middle of the head ; the other is convex, and is turned outwards to correspond with the internal flange of the humeral condyle. Its prominence is continued from it, presenting inwards, and ceases distally abruptly in a semicircular edge. This strong recurvature of the humeral surface is characteristic of the species. The distal extremity is rather large. Its superior surface presents the wide open groove for the extensor tendons, which is bounded on the outer side by an obtuse ridge- 368 TUE WASATCH FAUNA. like tuberosity. The external fiice above the ulna is slightly concave, and is separated from the ulnar tace by an angular ridge. The internal face has the same relation to the inferior face. The scapho-lunar facet is undi- vided, and has a wide crescent shape, the concavity above and the angles rounded. As in the otlR-r species, the lunar bone is distinct from the scaphoid. The cuneiform is produced outwards into a narrow tuberosity. The magnum is small, and has a subquadrate anterior face. It rises above, as usual, and has a short posterior tuberosity. The metacarpals are not long, and the median ones are rather robust. The posterior keel of the distal extremity is obtuse and somewhat oblique, and separates parts of the condyle of unequal width and prominence. The supracondylar transverse groove is not deep, and the superior face of the condyle is rather flat. The head of a metacarpal has but one proximal facet, which is convex anteroposteriorly. There is a band-like lateral facet at right angles to the proximal, below which the bone is excavated abruptly. A phalange is wide and depressed, appro- priately to the flat claws. Its distal condyle is not recurved above. Measurements of anterior limb. M. Lcii)^lli of hiiraerus (partly iulerfiitiiil) • 165 TniiiHVerse di.imeter of head (partly Inferential) 041 Width at cpicondyles 0,j,5 ,,..,., <. , , (anteriorly 023 W id th of condyles < . ; „.,- ( posteriorly i "■^o . ,., , , < iiitomally 031 Aiiteropiwterior width condyles < _ .Z .„ ( externally O^y Leii({th of ulna -^^ L(ni;tli of olecranon 0/0 Depth of (decranon at ex'reniity of olecranon 026 Depth of olecranon at coronoid process 051 Depth of olecranon at head of radius 026 Depth of olecranon at middle of shaft 019 Width of cuneiform facet of ulna 013 Len);lli of radius 202 (vertical 0185 Diameters of head of radius < ' ' ,,„. ( traiisvers* "•" Width of shaft at middle 020 Width at distal end 039 Width of carpal facet ^^'* Depth of carpal facet 015 Depth of face of lunar 015 Width of face of lunar 013 Depth of face of cuneiform OH Width of face of cuneiform 026 CREODONTA 369 M. Length of a metacarpal 069 Width of a metacarpal distally 019 Width of condyles 015 Diameters of a head of a metacantal J ® ^" "■ < transverse 01 J Length of a. phalange 024 „. ^ /. V 1 It < vertical at middle 012 Diameters of a phalange proximally < ( transverse. 017 The posterior limb is quite elongate. The tibia has the length of that of the Ursus americanus, while the femur is a little shorter than the femur of the same species. In Mesonyx ossifragus it is a little longer than the tibia ; in Ursus americanm the difference in the proportions of the two bones is greater. The femur has more prominent greater and lesser trochanters than either Ursus americanus, Canis lupus, or Uncia concolor. The great tro- chanter projects beyond the line of the head, and its extremity is compressed anteroposteriorly. The trochanteric fossa is large, and is more open than in either of the three Carnivora above mentioned. The lesser trochanter is compressed and large. The third trochanter commences a little below the line of the inferior edge of the little trochanter. It has a long base, but is obtuse and little prominent. The fossa ligamenti teris is much larger than in either of the species above mentioned, and extends to the neck of the femur. The shaft of the femur is rather stout, and has a large medullary cavity, which in the specimen is filled with calcareous spar The walls are not thicker than in some Dinosauria. The linea asper is impressed, and vanishes inferiorly. The rotular groove is wide, and its bounding crests are rather high, and are subequal. The proportions are about as in Uncia concolor, being less elevated than in Canis lupus, and more so than in Ursus americanus. The edges are reflected above the rotular curface, a peculiarity not seen in either of the species named. The fossa at the external base of the rotular face is present as in Ursus and Canis. The condyles are sub- equal, are regularly convex, and are not much produced backwards. Measurements of femur. M. Length from summit of great trochanter 315- Width of head 077 Anteroposterior diameter of head .... O'iZ Width at third trochanter.. 048 24 C 370 THE WASATCH FAUNA. Will til bflow third troohaiitor 032 Width above condyles 061 Width of condyles 058 Width of rotiilar groove 030 Depth i>( inner condyle with rotular crest 05d The tibia has a nearly straight shaft, which is rather slender below. Its section below the head is triangular, the base being posterior. That of the inferior front of the shaft is also triangular, the base of the triangle being the inner side. The crest is quite prominent, not flat, as in Ursus, but not quite so strong as in Uncia concolor. It is replaced by a gentle conve.xity just below the middle of the shaft. The inner femoral cotylus does not overhang the inner side of the head. The latter has a wide, low, longitudinal ridge posterior to the middle, which distinguishes conca\'ities iinterior and posterior to it. The external femoral face is decurved poste- riorly, and rises into a spine posterior to the middle of the boundary be- tween it and the internal face. There is a transverse depression at the summit of the spine. The latter has a superior and an inferior tuberosity. The internal malleolus is produced. Its internal face carries a groove for the tendons; part of the surface is damaged, so that more than one cannot be determined. The trochlear face is divided into two fossae, which are not so deep as those of M. ohtusidens. The fibular proximal facet is not Measurements of tibia. * ^ Total lingth 275 Dianirtors of head ^""'""P""*"'"'" (**"»!) ^ I transverse 062 fore and aft 022 transverse 023 Wam.t.r.-. of distal end? ""♦•^"■"P""'"'''"^ *» Diameters just below middle of shaft \ ° I tr transverse 039 The only tarsal bones preserved are the astragalus and calcaneum. These were found nearly in place, adherent to the distal extremity of the til)ia. They are about the size of those of the black bear, and larger than tho.se of the M. ohtmldens. The astragalus has the same peculiarity as that of the M. ohtusidens, in the distinct band-like facet of the external side of the distal extremity for articulation with the cuboid bone; a peculiarity un- kiiiiwn elsewhere among Creodonta and among Caraivora, The width of this surface is about one-half that of the navicular surface, and it is of uni- form width, extending obliquely to the middle line. The navicular face is CREODONTA. 371 deeper than wide, and is convex anteroposteriorly and concave transversely. Its internal part is reverted to the inferior side, no doubt to accommodate the posterior process of the navicular. The general appearance of this double articulation is much like that of a perissodactyle ungulate. The trochlea is wider and not so convex nor so deeply grooved as in M. obtiisi- dens. It is hour-glass shaped, and the external face has considerably greater extent than the internal. The former is vertical except the anterior part, which descends as an angular process into a fossa in front of the calcaneal condyle, which is flared outwards. An articular band marks the inner face of the trochlea continuous with the general surface. The postero-intemal angle is produced, as in Oxyoena, into a flat subhorizontal rounded process, which overhangs the sustentaculum. The neck of the astragalus is much shorter than in M. obtusidens. The posterior outline is widely and deeply notched. The calcaneum is long and rather narrow. The sustentaculum and the superior condyle are both small. Below the lattei', on the external face, is a strong longitudinal crest continuous to the cuboid face. This crest in Oxycena and in carnivora stops at or before the vertical line of the anterior end of the condyle. Beneath it the side of the calcaneum has a deep longi- tudinal concavity. The free extremity is truncate. The cuboid surface is large, but imperfection of the specimen obscures its external boundary. It is flat and not very oblique to the axis of the bone. Measurements of tarsus. Length of astragalus ou inner side 044 Lengtli of internal arc of trochlea 024 Length of external 031 Depth of inner side at trochlea 023 Length of neck of astragalus 015 Anteroposterior diameter of distal end 022 Diameters navicular facet ^°''''1"« ^^* ( transverse 016 Diameters cuboid facet J "•'1'1«« ^^ I transverse 007 Length of calcaneum 077 Depth at free extremity 027 Depth at condyle 034 Depth at cuboid facet 026 Width at free end 022 Width at sustentaculum ,,. , 041 Depth (vertical) of cuboid facet 023 372 THE rUEKCO FAUNA. Portions of a second individual of Mesonyx were found by Mr. Wort- man in the Big Horn region. Of this I must observe that the head of the radius has not the anterior flare of the inner side of the M. ossifragus, but it resembles more nearly the corresponding part of the M. lanius, though it presents some minor differences. The superior concavity is strong. The axis vertebra has a rather long odontoid, with circular section and confluent articular surfaces. The centrum has a strong hypapophysial heel, which is laterally expanded posteriorly. The posterior articular face is moderately oblique, and is plane excepting a central depression. The vertebrarterial canal is wide. Comparison of this axis with those of Carnivora and Marsupialia yields the following results: It differs from all the principal genera of the former order, and from Didelphys and Phascolarctos of the latter, in the nearly round form and downward extension of the atlantal facets. Tlie form is approached by that of the Sarcophilus nrsinus, but is not so j)ronounced in the latter. The strong hypapophysis is ai)proached by Felkhc only among Carnivora, and by Dkhlphi/a among Marsupialia. The size of the axis is about that of the Crocuta maculata. Two ungual phalanges which accompany this specimen have nuich the form of those of M. lanius. The proximal part is claw-like, but the distal part narrow hoof-like. The extremity is deeply fissured; the sides are acute and flat, and there is a median inferior table, which widens poste- riorly. It is separated by a groove from the lateral edge, which is deeply impressed posteriori}-. Tlie acute lateral edges are spongy. Measurements of A'o. 2. m. Length of axia 1*0 LeoRth of axis to base of odontoid ('48 Diani.'t«T8 of atlantal facet| vertical (fji < horizontal VJl Width of centrum behind atlantal facet 032 Diameters of posterior face centrum < " "'^ ,,„„ ( tranHVeroe I'JO Diameters of head of radius^ "'"''=»' ^J^ I transverse y''^ Len)(th of phalange ' Diatoeters distal end phalange | ''•''■^''''' II*'l* ( transverse •'!•' Length of nngnal phalange (•■-1 Diameters proximally 5 ^"^""»1 ^"^ ( transVctSe 010 Width of expanse OlOS CHIROPTERA. 373 Portions of several other individuals were found by Mr. Wortmau in the bad lands of the Big Horn Basin. Restoration. — From the preceding investigation we can form a general idea of the form and proportions of the Mesonyx ossifragus. We can depict an animal as large as a lai'ge-sized American black bear, with a long stout tail, and a wide head as large as that of a grizzly bear. The fore limbs are so much shorter than the hind limbs that the animal customarily sat on its haunches when on land. In walking, its high rump and low withers, would give it somewhat the figure of a huge rabbit. Its neck was about as long as that of an average dog. Its tread was plantigrade, and its claws like those of various rodents, intermediate between hoofs and claws. The animal, to judge from its otter-like humerus, was a good swimmer, although there is nothing specially adapted for aquatic life in the other bones of its limbs. Its teeth, on the other hand, are of the simple construction of the mammals which have a diet largely composed of fishes. We cannot but consider this animal as one of the most singular which the Eocene period possessed. In size it was not exceeded by any other flesh-eater of the period, but was equaled by the Protopsalis tigrinm. CHIROPTERA. Species of this order were first detected in the Eocene formations of France by Cuvier, who named a species from the gypsum (Upper Eocene) Vespertilio parisiensis. In North America, Pi-ofessor Marsh has recorded them from the Middle Eocene (Bridger), but whether they belong to existing generic forms or not is yet unknown. The oldest North American species is described below. It is from the Wind River region, which represents the Lower Bridger. VESPERUGO Keys & Bias. Wirbelthiere Europas, 1810, p. 45. 9 1 2 3 I.-; C. -; Pm. — ;M. -. First and second superior tme molars o 1 ^ — O O with two external Vs, and an internal heel, which supports a more or less elevated cusp. Inferior molars like those of Didelphys, with an anterior triangle of three cusps and a cuspidate heel. 374 THE BRIDGER FAUNA. VeSPERUGO ANEM0PHILU8 Cope. Bulletin U. 8. G*ol. Surv. Terrs, vi, 1h8', p. ;»4 ; American Naturalist, 1880, p. 745. Represented by the anterior part of a skull without lower jaw. Den- tition: I.?; C. 1; Vm. 2; M. 3. Posterior molar narrow; its posterior external V rudiniental ; first and second molars subequal. Fourth premo- lar elevated and acute, with an external basal cingulum; second premolar simple, acute. Profile steeply elevated behind orbital region, less steep in front of it; zygomas wide. Measurements. H. Leu{;tli from iiitcrorbital region to above canine alve'olns in front ^ 010 Intcrorbital width 005 Width ot zygi)ma.s 012 Width between outsides of last molar teeth 010 Length of molar series 008 Length of true molars 004 Found by J. L. Wortman. TAXEOPODA. Cope, American Naturalist, 1882, p. 523, June (May 30). Ungulate ; carpus with the bones of the second row directly succeeding those of the first. The lunar bone is supported by the magnum, and little or not at all by the unciform, and the scaphoid is supported by the trapezoides and not by the magnum. In the same way the bones of the second series of the tarsus do not alternate with those of the first series. The astragalus ar- ticulates exclusively with the navicular, and the calcaneum with the cuboid. Tliis comprehensive division is, so far as present knowledge extends, well distinguished from the best known orders of ungulates, the Amhhjpoda, the Perissodactyla, and the Artiodactyla. The ungulata are here understood to be the hoofed placental mammalia with enamel-covered teeth, as distinguished from the ungulate or clawed, and the mutilate or flipper limbed, and the edentate or enamelless groups. The exact circumscription and definition has not been attempted, though probably the brain furnishes an additional basis of it in the absence of the crucial and presence of other fissures, etc. Suffice it to say that it is on the whole a rather homogeneous body of mammalia, especially distinguished as to its economy by tlic absence of forms accustomed to an insectivorous and carnivorous diet, and embracing the great majority of the herbivorous types of the world. TAXEOPODA. 375 The internal relations of this vast division are readily determined by reference to the characters of the teeth and feet, as well as other less im- portant points. I have always insisted that the place of first importance should be given to the feet, and the discovery of various extinct types has justified this view. The predominant significance of this part of the skel- eton was first appreciated by Owen, who defined the oi'ders Perissodactyla and Artioductyla. Professor GilP has also used these characters to a certain extent, but without giving them the exclusive weight that appears to me to belong to them. Other authors have either passed them by unnoticed, or have correlated them or subordinated them to other characters, in a way which has left the question of true aftinity, and therefore of phylogeny, in a very unsatisfactory condition. Much light having been thrown on these points by recent discoveries in paleontology, the results as they appear to me are here given. Carpus. — It is well known that in the Peris- soflacfi/Ja and AriiodactyJa the bones of the two r%^"' „^^5s^'iyi rows of the carpus alternate with each other; that the lunar, for instance "Iolo on the unci- form, and to a varying degree on the magnum, and that the scaphoides rests on tlie magnum ( and to some degree on the trapezoides and trapezium. It is also known that in the Pro- boscidea another state of affairs exis^^; i. e., that the bones of the two rows do ".ot alternate, but ^'<^- n-Left anterior foot of Eie- pliaa africaniis (from De Blainville). that the scaphoides, lu'^-ar, and cuneiform, rest One-tenth natural size. directly on the trapezium and trapezoides, the magnum, and the unciform respectively. The preceding characters are sometimes included in the definitions of the respective orders. Further than this they have not been used in a s^ocematic sense. ^xofessor Gill says of the carpus of the Hi/racoidea, "carpal bones in vwo interlocking rows ; cuneiform extending inwards (and articulating with 'Arrangement of tlie families of Mammals prepared for the Smithsonian Institntiou. Miscel- laneous Collections, 230. Nov., 1872. 376 TUE KOCEyE PERIOD. magnum); * * unciform and lunar separated by the interposition of tlie cuneiform and magnum." Professor Flower' gives a figure wliicli justifies these statements, but neither the one nor the other agrees with my specimens. In the manus of a Hifrar cuprxfiis (from ^'erreaux ^i Paris) I find the following condition of the carpus. The bones of the two series are articulated consecutively, and not alter- nately; they do not interlock, but inas- much as the magnum is a little narrower p,,, i;; _Richtante- FiG. 12 -Left ante- than the lunar, tlic latter is just in con- '■'"■ *■"»'"•' ".vo-r ca- ^ i. i: r.i J ' ptiisis (from Ciivier). T,oT {oot,o( Phenaooaus ^^^^ (anteriorly) with the trapezoides 5r. sca,.hoi,i bono: ;. ,.,..,./ i. 1 \ ii • 1 1 ii T lunar; <•«. ciini'ilorm : narnriiisize(onginai). (centrale)on tlieonesule, and tlieuncirorm . ., , . *• ^ ' p. pisifonn; t:. trape- on the other. My specimen agrees with Cuvier's figure ^'""'; 'rf- trapezoides; of llifrax cujiensis in all respects. It is probable that Pro- f„rm. Natural size. fessor Flower has figured some other species under that name, which besides its peculiarities, is of smaller size. In April, 1875," I described the manus of Conjphodon (Bathmodon), showing that theluii.irwas supported below h\ the magnum and by parts of the trap- ezoides and unciform. This carpus has the character of that nf Ifipax cdpoisis, with the two last named articulations more ex- tensive. This was the first description of the carpus of the AmhJ'jpodd. In Febru- ary, 187(i,^ Professor Marsh described the" cai'pus of Uiutathcriuni (Dinoccras), in Fio. 14.— Richt niaiiMsof ron//)Ao7 ; pi. vi, fig. 2. TAXEOPODA. 377 to the interlocking carpus. The trapezoides does not join the lunar, but the unciform does so, as in Coryphodou. Professor Marsh's figure as to the articulations of the magnum does not agree with his description, as it makes that bone articulate with the scaphoid. The second description is however correct, and the carpus is identical with that of Coryphodon. In the American Naturalist, June, 1882,^ I have shown that the carpus of the Condylarthra is essentially like that of the Hyracoidea. Tarsus. — In the tarsus of the Perissodadyla and Artiodactyla it is well understood that the cuboid e.xtends inwards so as to articulate with the astragalus, giving the latter a double distal facet. It is also well known that the astragalus of the Pro- boscidea has but a single distal articulation, that with the navicular. It is, however, true that the cuboid is extended inwards, but that it articulates with the distal extremity of the navicular instead of that of the astragalus. It was shown by Cuvier tliat the astragalus of the Hyracoidea articulates with the navicular only, and that the cuboid is not extended in- wards so as to overlap the latter. In 1873^ Marsh stated that the astragalus of the Amhly- FiG. i5.-Fore leg and foot of Hy- ^^^j^, articulatcs with both cuboid and navicu- racotherium renticolum (original). Two- thirds natural size. lar. Finally I discovered in 1 88 P that the astragalus of the Condylarthra articulates witli the navicular only, and that the cuboid articulates with the calcaneum only. In the tarsus then there are four types of articulation, which are represented by the Condylarthra, the Proboscidea, the Amhlypoda, and the Artiodactyla respectively. Orders. — From the preceding considerations we derive the following definitions of the primary divisions of the Ungulata, which should be called orders. In the first place I find the diversity in the structure of the carpus to be greater in the relations of the magnum and scaphoides, than in the relations between the unciform and the lunar. In other words the trape- 'Page 522. 'American Journal Science and Art, January, 1S73. 'American Naturalist, 1881, p. 1017. 378 THE EOCENE PERIOD. zoides and magnum are more variable in their proportions than is tlie cunei- form. This is directly due to the fact that the reduction of tlie inner two digits is more usual than the reduction of the external two. I therefore view the rela- tions of these bones as more characteristic. In the tarsus the really variable bone is the cuboid. It is by its extension inwards that the additional facet of the astragalus is pro- duced. Its relations will therefore be con- sidered rather than that of the astragalus in framing the following definitions : Order I. Staphoides supported b.v trapezoides and A not by magnum, which supports lunar. Cuboid nrO Fig. 10.— Left pos- Order III articulating i)roximally with calcaneuni only. Taxeopoda. Order II. Scaphoides supported by trapezoides, terior Toot of Phena- and not by magnum, which with iincilbrin sup- Fig. 17.— KigUt po8- and not by magnum, winch .supports lunar. ,^.^j^^ ^^.^.^ ^^ ^^^^^ Cuboid extciulcd inwards and articulating with odpensis (from c a vier). the distal t;u;e of the navicular.. . .Proboscidea. Ca. cilcaiK-nm : a. as- Scaphoides supported by trapezoides trngaUis;M. navicular; CM. cuboid ; ecc. ecto- codus primcnus. one- ^j.^^ ^]^^ i^^ar. Cuboid extended inwards and cuneiform ; "enc. enti iir( Dft ura size articulating with astragalus Amblypoda. QuneHoim. Nat. size. (origuial). o o Order IV. Scaphoides supported by magnum, which with the unciform also supports the liuiar. Cuboid extended inwards so as to articulate with the astragalus. Diplarthra. The sub-orders are defined as follows: I. TaXE0P0D4. There are two, perhaps three sub-orders of the Taxeopoda, the Hyra- coidea, the Condyhrthra, and perhaps the Toxodontia? The Toxodontia are however not sufficiently known for final reference.* The sub-orders are defined as follows: A jioHt glenoid process; no fibular fiUM't of calcaneum, but an interlocking articulation between fibida and astragalus; ungual i)lialanges truncjit* Hyracoidea. A post-glenoid i)r(K;ess; no tibular facets on either wilcaneum or astragalus; a third trochanter of the fennir; ungual phalanges acuminate Condylarthra. ' See my remarks on Toxoe possessing it, and the extinction of nearly all the species of the type which does not possess it. Here is aj)plied again the principle first observed by Kowalevsky in the prox- imal metapodial articulations. This author shows that the i ) tj-pes in which the metapodials articulate with two carpal or tarsal bones, have survived, while those in which the articu- lation is made with a single carpal or tarsal have become extinct. The double articulation is, of course, mechanically Q V Cj8 the more secure against dislocation or fracture. " f r As regards the inner part of the man us 1 know of no genus FiG.20.— Hind .^^.j^jp]^ presents a type of carpus intermediate between that of the foot of Poebro- * ' * ' tiie>'i tl'G Other. Such will, however, probably be discovered, uatiirai size. ^^^ ^|,g earliest Permodactyla, n>i for m^tance Hi/racotherii())i, Hyrachyus, and Triphpus, possess the carpus of the later forms, Rhinocerus and Tapirus. The order Amhiypoda occupies an interesting position be- tween the Taxeopoda and Diplarthra, for while it has the carpus of the jn-imitive type, it has the tarsus of the later order. The bones of the tarsus alternate, thus .showing a decided advance on tlie Taxtopoda. This order is then less primitive than the latter, although in the form of its astrag- alus it no doubt retains some primitive peculiarities which none of thd TAXEOPODA. 381 known Taxeopoda possess. I refer to the absence of the trochlea, a character which will yet be discovered in the Taxeopoda, 1 have no doubt. The Taxeopoda approach remarkably near the Bunotheria, and the ungiiiculate and ungulate orders are brought into the closest approxima- tion in these representatives. In tact I know of nothing to distinguish the Condylarthra from the Mesodonta, but the ungulate and unguiculate characters of the two divisions. In the Creodonta this distinction is reduced to very small proportions, since the claws of Mesomjx are almost hoofs. Some of the genera allied to Periptychus, present resemblances to the Creo- donta in their dentition also. The facts already adduced throw much light on the genealogy of the Ungulate Mammalia The entire series has not yet been discovered, but we can with great probability supply the missing links. In 1874 I pointed^ out the existence of a yet undiscovered type of Ungulata, which was ancestral to the Amblt/poda, Proboscid^a, Perissodactyla, and Artiodadyla, indicating it by a star only in a genealogical table. This form was discov- ered in 1881, seven years later, in the Condylarthra. It was not until latei*^ that I assumed that the Diplarthra are descendants of the Amblyjwda,. although not of either of the known orders, but of a theoretical division with bunodont teeth.^ That such a group has existed is rendered extremely probable in view of the existence of the bunodont Proboscidea and Condy- larthra. That the Taxeopoda was the ancestor of this hypothetical group a* well as of the Proboscidea, is extremely probable. But here again neither of the sub-orders of this group represent exactly the ancestors of the known Amblypoda, which have an especially primitive form of the astragalus not found in the former. In the absence of an ankle-joint, the Pantodonta are more primitive than any other division of the Ungulata, and their ancestors are not likely to have been more specialized than they. It is probable that a third sub-order of Taxeopoda has existed which had no trochlea of the astragalus, which I call provisionally by the name oi Platyarthra. The preceding paragraphs were written in May of the year 1882^ 'Homologies and Origin of Teeth, etc., Journal Academy Nat. Science, Philada., 1874, p. 20. ^Report U. S. Geol. Survey W. of 100th Mer., p. 28^, 1877. ^This hypothetical sub-order is called in the above scheme Amblypoda hyodouta. 382 THE EOCEXE PERIOD. On my return home, September Ist, after an absence of three months, I found that various parts of the skeleton of Periptychus^ have reached my museum. On examination, I find that the astragalus of that genus fulfils the anticipa- tion above expressed. It is without trochlea, and nearly resembles that of Elephas. As it agrees nearly with that of Phenacodus in other respects, I only separate it as a family from the Phenacodontidce. One other type re- mains to be discovered which shall connect the Periptychidce and the hypo- thetical Hyodonta, and that is a Taxeopod without a head to the astragalus — unless, indeed, the "Hyodonta" should prove to have such a head. I think the latter the less probable hypothesis, and hence retain the term Platyar- thra for the hypothetical Taxeopod without trochlea or head of the astrag- alus. These relations may be rendered clearer by the following diagram: Taxeopoda. Condylarthra, Platyarthra.* Hyracoidea. \ Pboboscidea. Amblypoda. Hyodonta.* Pantodonta. I Dinocerata. DiFLABTHBA. / \ Perissodactyla. Artiodactyla. The preceding classification was first published in the Proceedings of the American Philosophical Society, October, 1882, after having been read at the Montreal meeting of the American Association for the Advancement of Science, August 29, of the same year. CONDYLARTHRA. Cope, American Natnralist, 1881, p. 1018, November 29. In a paper on the "homologies and origin of the molar teeth of the Mammalia Educabilia, published in March, 1874,' I ventured the generali- ' Si'o Ariicricaii Nataraliat, October, 18s2. 'Hypothetical. 'Journal of the Acatlemy of Natural Sciences, Philadelphia. CONDYLARTHKA. 383 zation that the primitive types of the Ungulata would be discovered to be characterized by the possession of five-toed plantigrade feet, and tubercular teeth. No Perissodactyle or Artiodactyle mammal was known at that time to possess such feet, nor was any Perissodactyle known to possess tubercu- lar teeth. Shortly after advancing the above hypothesis, I discovered the foot structure of Coryphodon, which is five-toed and plantigrade, but the teeth are not of the tubercular type. For this and allied genera, I defined a new order, the AmUypoda, and I have published the confident anticipa- tion that genera would be discovered which should possess tubercular (bunodont) teeth. This prediction has not yet been realized. The discov- er}' of the Condylarthra went far towards satisfying the generalization first mentioned, and indicates that the realization of the prophecy respecting the AmUypoda is only a question of time. In 1873' I described, from teeth alone, a genus under the name of Phenacodus, and although a good many specimens of the dentition have come into my possession since that date, I have never been able to assign the genus its true position in the mammalian class. • The teeth resemble those of suilline Ungulates, but I have never had sufficient evidence to permit its reference to that group. Allied genera recently discovered by me have been stated to have a hog-like dentition, but that their position could not be determined until the structure of the feet shall have been ascei'tained." In his recent explorations in the Wasatch Eocene of Wyoming, Mr. J. L. Wortman was fortunate enough to discover nearly entire skeletons of Phenacodus primcevus and P. vortmani, which present all the characters essen- tial to a full determination of the place of Phenacodus in the system. The unexpected result is, that this genus must be placed in a special group of an order which includes also the Prohoscidea? The astragalus in this sub-order is absolutely undistinguishable from that of the flesh-eating groups Creodonta and Carnivora. The humerus also presents a character of the unguiculate orders, in possessing an epicondylar ■ PaliEoatological Bulletin No. 17, Oct. 1873, p. 3; also, Report G. M. Wheeler, U. S. Engineers Expl. W. 100 Mer.. iv, p. 174, 1877. 2 Proceed. Amer. Philosoph. Society, 1881, p. 495. ^AJierican Naturalist, June, 188-2 (May 17). 384 THE EOCENE PEKIOD. foramen, which is elsewhere unknown among ungulates. The humeral condyles have the generalized character of the same type of the Amhlypoda, and of the lower Perissodacti/la, in lacking an intertrochlear crest.' The Condylarthra may then be further defined as follows r Astragalus with one uniformly convex distal articular face ; humerus with epicondylar foramen. This sub-order has as yet been only found in the lowest horizons of the Eocene period, the Puerco and Wasatch, and only on the North American Continent. Appropriately to this position in time, its structure indicates that it is the most primitive type of the Ungulata. A number of genera and species belong to it, and these fall into three families, which are detined as below. They conform to the definitions of the order in possessing the normal mammalian type of dentition, without specialization, and a third trochanter of the femur. The approximation to the Hyracoidea is greater than that of any other group of the Taxeopoda. That order agrees with the Condylarthra in the simple articular extremity of the astragalus, which is, however, less convex ; but it has a very peculiar articulation with the ante- rior face of the extremity of the fibula, seen in no other group of ungulates. In the manus of the Hyracoidea the lunar bone is very peculiar, not being divided below into two facets, as in most other ungulates, and generally extending to the carpals of the trapezoides series (the intercalare), as well as to the unciform. In this point the Hyracoidea come nearer to the Atnbly- poda. In Hyrax there is also no epicondylar foramen. The three families of Condylarthra are defined as follows : Dentition buiKMloiit; toes 5 — 5; axtragaliis without trochlea; neck very short ; pre- molars vf.Ty simple above and below Periptyvhida: Dentition bunodont; toes 5 — 5; astragalus with trochlea; neck longer; jiremolar teeth different from the molars above and below . PheiuiaxhiHtiilw. Dentition loj>h(»dont, with crescents and deep valleys; premolars partly like molars below; neck longer! Menigcotheriidcv The bunodont dentition, with very simple premolars, flat astragalus, and five toes on all the feet, give the Periptychidce the lowest place in the sub-order and order, as the most generalized type known. The Meniscothe- riidce have a quite specialized dentition, and until I learned its Condylar- > American Naturalimt, Apnl, 168^, p. 334. •Amer. NatnroliHt, 1881, p. 1017, Not. ». CONDYLAETHEA. 385 throus character, I was at a loss to account for the presence of such per- fection in so old a type. The number of the toes is yet unknown. The family appears to have had no descendents, and is a good illustration of Dr. Kowalevsky's views as to the persistence of the "adaptive" over the "non-adaptive" types of articulation. Kowalevsky observed that the types of Ungulata, which have the carpo-metacarpal and tarso-metatarsal articu- lations simple and not alternating, have become extinct. In those which persisted, the metapodials articulate with two bones of the carpal or tarsal series. The same rule has generally applied in the Ungulates to the distal astragalar articulation. The orders with the double articulation have left descendents, while the Condylarihra with the single articulation have disap- peared without leaving a trace. The Proboscidea, which have the same simple distal articulation, still remain, however, to show an exception to the generalization. They have, however, an alternation in the second series of the posterior foot not present in the Taxeopoda. The relations of the genera of these three families are as follows : Periptychidae. In Periptychus only are the posterior feet known. The carpus is yet unknown. The successional modifications are seen in the addition of cusps to the inner sides of the premolars of both jaws, and the true molars of the upper jaws. In Periptychus we have the largest number of dental cusps and lobes, and in Anisonchus the next. With that genus the inferior pre- molars lose their inner ledges, and the true molars their anterior internal lobes. The latter are still further reduced in Hemithlceus, and the former in Haploconus. It is possible that Conoryctes belongs to this family. In all of my specimens of this genus the faces of the molars are so worn that I can- not see the pattern, and the ungues are unknown. There is, however, a general agreement in the known parts of the skull and skeleton. If it enters here it will be characterized by the perfect V's of the inferior molars. The following are the characters of the genera: I. Intermediate tubercles present; inferior premolars with internal lobes. Superior molars with two internal cusps besides apex of V; superior premolars with internal lobes Periptychus. 25 o 386 THE EOCENE PERIOD. TI. Tiitorinediate tubercles wanting; inferior premolars without internal lobes. Superior molars with post4?rior internal cusp only, besides internal V; last two supe- rior premolars with internal lobes Anisoiichiis. Superior molars with internal V only, no other Internal lobes; last two superior pre- molars with internal cusps Hemithltnts. Superior molars with posterior internal cnsp only, besides apex of V; fourth superior premolar only with internal lobe Haploconxis. PHENACODONTID.fi. The genera of this family display a uniformity in the structure of the true molar teeth not seen in the PeriptychicUB. Their range of grade is seen in the premolars, especially those of the superior series. Thus in Protogonia, all of those teeth have but a single external lobe. In Phenacodus, the fourth has two external lobes. In Dlacodexis, the second, third, and fourth teeth have two external lobes. The premolars are unknown in Anacodon. While Protogonia is primitive in its superior premolars, its inferior true molars come nearer to developing V's than any other genus of the family. The definitions are as follows: Last superior premolars with but one external cusp; inferior molars with Vs. Protogonia. Last superior premolars with two external cusps; inferior molars with well-developed cusps Phenacodus. Inferior molars with flat frrinding faces; no cusps Anacodon. Second, third, and fourth superior premolars with two external cusps ; those of inferior molars well developed I>iacodexi«. Meniscotheriid.*:. This family includes the single genus Meniscotherium. Superior molars with intermediate tubercles, the anterior crescentic, the posterior oblique, forming a crest with the posterior inner; anterior inner conic. Inferior molars and last premolar with two Vs; other inferior j^remolars without int< rnal lobes; fourth superior premolar with two external lobes Meniscotherium. CONDYLAETHKA. 387 The geological distribution of the nine genera of these families is as follows : Haploconu8.. HemithljBus Anisonchus .. Periptychns Protogonia . . Anacodon . . Phenacodns Diacodexis . . Men iscotherium PeriptychidcB, Phenacodontidce. Meniteotheriidce. Puerco. 17 Wasatch. 11 PERIPTYCHUS Cope. American Naturalist, 1881, p. 337 (March); Catathlmus, Cope, American Naturalist, 1881, 829, Sept. 22. Proceeds. American Philosoph. Soc, 1881, p. 487. Dental formula: I. 2or3 1 C. -; Pm. -; M. -. Premolars of superior jj ' - 1' -— 4' —3 series consisting of external conic cusp, and an internal crescentic crest, which is like a developed cingulum surrounding the cusp. Crowns of true molars supporting seven tubercles, as follows: two external; one principal median internal, which has accessory cusps, one anterior and one pos- terior to it; lastly, two, an anterior and a posterior intermediate tubercles. Diastemata in both series small. Inferior incisors small; canines of mod- erate size. Inferior premolars consisting of one principal external cusp, and an internal cingulum. This rises medially into an accessory cusp, and , extends posteriorly into a narrow heel, and anteriorly into a small anterior basal tubercle. The inferior true molars sustain four principal cusps op- posite in pairs, with accessory median ones on the anterior and posterior borders. The posterior median lobe is so developed in the last inferior molar as to constitute a fifth lobe or heel. 388 THE PCTERCO EPOCH The angle of the lower jaw is not reflected nor inflected. A part of the condyle with adjacent regions shows several features. The coronoid process rises near the condyle, and in precisely the same plane as the angle of the jaw. Both leave the condyle near its inner extremity. The articular face of the latter looks upwards and backwards about equally, and is rather flat. A fragmentary skull shows a postglenoid crest, and the robust post- tympanic and paroccipital processes united, and leaving the meatus audi- torious externus widely open below. The os petrosum is small and not inflated. The foramen ovale is not separated from the meatus auditorius below. There is a postglenoid foramen, and a supraglenoid foramen There is also a well-marked mastoid foramen. The mastoid bone is extensively exposed. The cranial walls are thick. Such part of the cast of the brain as appears, gives the following points: The hemispheres are very narrow, and rather elongate, and are separated by a long flat crus from the olftictory lobes. The latter are very large and nearly as wide as the hemispheres. The posterior three premolars are preceded by temporary teeth in both jaws. Of these the anterior is protruded at about the same time as the first true molars, and is the last one shed, remaining until after the last true mo- lar is fully protruded. The last milk premolar diflers from the coirespond- ing permanent one in its gi-eater elongation. The extension is posterior, in the form of a heel with three tubercles, of which the median is very small, the crown resembling a permanent true molar, except that the anterior por- tion is a little more elongate and compressed. The anterior basal lobe is a mere elevation of the cingulum, as in the permanent premolar, lint the internal cusp is more distinct than in the latter. The penultimate milk pre- molar is more like the corresponding permanent tooth, l)Ut is a little more flattened and elongate, and the heel is not tubercular. The first milk molar is a little more compressed than the corresponding i)ermanent tooth, and the edge of the heel is not tubercular. Otherwise they are sinular. It was on a specimen supporting the last two milk molars, with the first true molar so injured that its true character could not be ascertained, that the Periptychus carinhlcns was established. COISTDYLARTHRA. 389 The base of the diapophysis of the atlas is perforated as in the suc- ceeding cervicals. The Literal perforating foramen is entirely isolated. The axial facets are separated. The axis is depressed and moderately short. The odontoid is depressed, and has an oval section. The cervical vertebrae -are much shorter than in Phenacodus, being deeper than long, and wider than deep. They are very slightly opisthoc^lous. The caudal vertebrae are quite robust, indicating a powerful tail. Dorsals not found. The tubei'osities of the humerus are small in proportion to the size of the head. The condyle is much like that of a creodont, with internal flange and external cylinder, without intertrochlear crest or ridge The internal epicondyle is large, and is pierced above by an epitrochlear foramen. The olecranon is compressed. The head of the radius has a flat articulation with the ulna. Its outline is a transverse oval, narrowed at the external extrem- ity. The scapula has a well developed coracoid hook, and the spine rises abruptly from the neck. In the P. rhabdodon the femur is not materially larger than the hume- rus. The great and little trochanter are well developed, and the third tro- chanter is situated low down, as in Phenacodus, and not opposite the little trochanter as in C'reodonta. The posterior foot has five digits. The astragalus is much like that of the Prohoscidea in form. The head is moderately long, and is depressed. Its distal extremity is regularly convex from side to side. The trochlea is borizontal, and is not grooved medially, but is very slightly concave. Fib- ular face vertical; malleolar fixce slightly oblique and occupied by a deep central fossa. The head is not as convex as in Phenacodus, but is more recurved on both sides. On the external side it is so far recurved as to be continuous (in P. rhahdodon) with the sustentacular facet, and a part of this face is probably in contact with the cuboid, as in many creodonta, but which cannot be said therefore to overlap the astragalus, as in the Anddypoda. If this facet were distal, and in the plane of the navicular facet, it would be necessary to refer this genus to that order. The calcaneum is robust. Its astragalar facets, especially the external, are rather flat. The cuboid facet is large, and is supplemented by an external tuberosity. The sustentaculum is well developed. Free portion 390 THE PUEECO EPOCH. lost in my specimens. The cuboid is robust, and not flat, extending well beyond the navicular. Its distal extremity does not display distinct facets. The navicular nuich resembles that of Phenacodus. It is proximally concave; its inferior aspect has three facets, of which the internal is largely posterior. The ectocuneiform has an elongate posterior tuberosity. It has also a proximal facet of the external side which corresponds with one of the na\ncular, for the cuboid. Its distal face is concave. Portions of two posterior feet preserved, display five metatarsals, and several phalanges. The distal carina of the former is posterior and weak. The latter are rather narrow for an ungulate, but are not elongate, and are rather depressed ; the distal ones are more robust, and are rather more nar- rowed distally than usual in ungulata, and the neck of a broken ungual phalange of an extei'nal digit is nearly round in section. The third digit is longest, and the first, shortest; it is not very short, and is quite slender. Sesamoid bones are probably present The posterior foot is that of a planti- grade animal. I have obtained a cast of the top and sides of the cerebral hemispheres, and the proximal portion of the olfactory lobes, from a skull of a Periptijchus in which the teeth are presei-ved, and prove the species to be the P. rhahdodon. I describe it in detail under that species, but state here that the olfactory lobes are enormous, and the hemispheres small and very fla^. The mesencephalon is entirely exposed. The position of this genus and its immediate sXXie?, Anisouchus, Haploco- nus, and Uemithlceus, is not yet positively determined. But three references are possible, viz, to the Taxeopoda Condylarthra, the Bunotheria Creodonta, and the Marsupialia. As no undoubted marsupial characters have been found, discussion of their affinities to that order is deferred. Nevertheless it must be remembered that there are no osteological characters common to all Marsu- pialia, and that the undoubted characteristics of that order can be found in the soft, parts only. The determination of extinct Marsupialia will, on this ac- count, always be difficult. The sculpture of the premolar teeth is not unlike that seen in the fourth premolar of Ptilodus. The character of the condyles of the humerus is, however, totally unlike that of Cutopsalis and Mcniscoessus. The dentition is against reference to the Creodonta. excepting CONDYLAETHRA. 391 as regax'ds the family of Arctocyonidce. The only suggestion of such affinity is found in the form of the astragalus, and in the narrow external phalanges. The astragalus of all the Condylarthra is undistinguishable from that of the Creodonta. It is almost certain that the middle ungual phalanges in Perip- tychus are much wider than the lateral ones, so that they are probably truly ungulate. The reference to the Condylarthra is indicated by the large infe- rior third trochanter of the femur ; also by the vertical aspect of the man- dibular condyle, with the identity of plane of the angular and coronoid plates. In the Creodonta, where this part is known, the coronoid pi'ocess and the angu- lar plate are, as in Carnivora, different. I except from this Ilesonyx, where they are in the same plane. There are three species of Periptychus, two of which differ principally in dimensions. Periptychus rhabdodon Cope. American Naturalist, Sept. (Oct. ), 1882. Catatklcerhua rhabdodon Cope. American Naturalist, 1881, October, p. 830 (Sept. 22). Paleontological Bulletin, No. 33, p. 487, 1881. Proceed. Amer. Philo. Soc, 1881, p. 487. Plates XXIII f, XXIII g, figs. 1-11 ; LVII f, figs. 1-2. This species was evidently very abundant during the Puerco epoch, portions of fifty individuals having come into my possession. These consist mostly of fragments of the jaws, superior and inferior. The most important of these specimens includes most of the dentition of the mandible and the posterior part of that of the maxillary bone ; fragments of the skull ; a number of vertebrae ; considerable parts of both limbs ; part of the posterior foot. A second specimen includes both jaws, parts of scapula and ulna, cervical vertebrae, femur and part of posterior foot. A third specimen in- cludes part of the lower jaw with condyle and teeth ; some vertebrae, and the astragalus. Another includes one mandibular ramus with symphysis. There are many maxillary bones with teeth, but no premaxillaries. All the teeth of this species (incisors unknown) are characterized by a remarkable sculpture of sharply-defined grooves and ridges. The ridges extend from the bases of the crowns to the apices of the cusps of the pre- molars and molars, and on the external sides of the teeth are straisrht. As they converge some of the ridges cease. On the interior faces of the crowns the grooves are less profound, and the ridges are more irregular in 392 THE PCTERCO EPOCH. direction and less closeh* placed. On the inner sides the sculpture may disappear with age, but never on the external .side. In their unworn state the internal cinguluni-crest of the premolars is coarsely serrate. They extend round the external cone to the posterior base, and to the outer base anteriorly, so as to aj)pear as a wide oblique mar- gin projecting antciior to the cone, on an external view. The external cone is compressed at the apex. The first superior premolar is unknown. No external cingula on the premolars, but a distinct one on the external base of the true molars. The latter have no internal cingulum, but there is one on both the anterior and po.sterior bases of the crowns which extend from the anterior and posterior internal tubercles, respectively. The two tuber- cles last mentioned ])roject farther inwards than the median internal tuber- cle, and are distinguished from it on the inner face of the crown by grooves. All the tubercles, including the external, ha\-e a subround section. The intermediate tubercles are the smallest, the other four being subequal. The jiremolars are remarkably large as compared with the true molars; the dis- proportion being greater in this than in niiv mammal known to me, except the Tetraconodoii of Falconer. The crowns of the inferior premolars are convex on the external side, and flat on the inner. Tlie principal and external cone is compressed at the apex in the anterior three premolars. The internal cusp is flat, and appressed to the external, and its apex is joined to the side of the latter. On trituration the two speedily become confluent, while the anterior and pos- terior basal lobes remain distinct, forming two lesser areas. The first infe- riiir premolar is a simple cone flattened on the inner side, and with a low posterior heel. Of the four principal tubercles of the inferior true molars the anterior external is the largest, and extends a little farther ante- riorly than tlie anterior internal. The anterior tubercle is on the inner side of the middle. On tlie last molar, the heel may have one or two acces- sory tubercles. The ramus is moderately robust and compressed. The inferior outline extends to the incisive border by a gentle slope, and rises below tin- last molar teeth. The masseteric fo.ssa is well marked in front, but has no dis- tinct posterior or inferior l)oundary. The su])erior true molars are placed Well posteriorly, or rather the; orl)it is anterior, for its anterior border is CONDYLARTHEA. 393 above the middle of the last premolar. The foramen infraorbitale is above the middle of the third superior premolar. The anterior part of the malar bone is quite prominent, overhanging the maxillary, and bounding a shal- low fossa which is open below. A crushed skull of the large variety displays a strong sagittal crest, arising from gradually converging rather obscure temporal ridges. Another skull has the parietal region much depressed, which is not altogether due to pressui*e, as the sagittal crest is partly intact. There is a strong supraoccipital crest, which is bilobed, the convex lateral portions being separated by a deep median notch. Between their bases the occipital face of the skull is concave. The paroccipital process is separated from the occipital condyle by a strong notch. It does not extend quite so far as the rounded, robust mastoid or posttympanic process, to which it is closely attached. At its inner base there is a rather large ? stylomastoid foramen. The postglenoid process is peculiar, being an angular ridge terminating interiorly in a low angular tuberosity. Its posterior side, or that of the base of the zygoma, is flat, and slopes for- wards and downwards. The glenoid cavity is nearly flat, and has no pre- glenoid crest, on the inner part at least; the rest of the border being destroyed in my specimens. The surface is cut off within by the groove, which, entering the roof of the meatus auditorius, I'epresents the foramen ovale. On the internal side of this groove there is a ridge, which, at its middle, swells into a tuberosity. The meatus auditorius is widely open. The postglenoid and supragleuoid foramina are rather small, and the latter is exactly above the postglenoid ridge. The mastoid foramen is on a line with the suprameatal ridge. The superior part of the mastoid bone just behind the posttemporal crest is pierced by another smaller foramen. The lengths of the last five inferior molars in this species vary from M. .065 to .055 ; and the inferior true molars from .035 to .033. The fol- lowing measurements are taken from two individuals : Measitrements. No. 1. H. Length of inferior dental series, less incisors 090 Length of inferior premolar series 046 Xength of inferior true molar series 034 Leuartliof basePm. i .. .108 394 THE PUERCO EPOCH. M. length of base Pm. iii 013 Width of base Pm. iii OCjo Length of base Pm. iv 013 Width of base Pm. iv 010 Diameters M. ; $ a^toroposterior Oil I transverse wv Diameters M. iii 5 ='"*^'^''1'°*"'"°' °^'^ ■ < auter c trans ransverse 008 Depth ramus at Pm. ii 0225 Depth ramus at M. iii 0296 Depth of ramus posterior to M. iii 052 Length of bases of two superior incisors 012 Diameter of base of crown superior canine 007 Length of superior true molars 028 _. . , . _ , .(anteroposterior 0096 Diameters of superior molar i < ■ ( transverse 01 1 _.. . - , ...< anteroposterior 009 Diameters of superior molar in ^ ^^ ( transverse 010 No. 2. Length superior premolar series 049 _. . T. .< anteroposterior 009 Diameters Pm. li '^ „.-. ( transverse 009o _. . „ ...(anteroposterior 013 Diameters Pm. in < ' < transverse 014 Elevation of occipital crest laterally above foramen maguum 044 Anteroposterior diameter of paroccipito-posttympanio process 017 Anteroposterior diameter of meatus auditorius 009 Anteroposterior diameter of glenoid cavity at postglenoid process 015 The cervical vertebrae, as already remarked, are about as long (or short) as those of the species of Ekphas, but are more depressed. The axis is less shortened, as its centrum has much the proportions of that of Bhinocerus. The atlas is shorter than in the latter genus. Unlike most genera of mam- malia, in PerijHychus, the vertebrarterial canal pierces the base of the ver- tically compressed diaparapophysis precisely as in Elephas. Its position is a little above opposite the fundus of the odontoid foramen, and nearly in the position it occupies in the Eleplias africanus. The condylar cotyli have full convex borders, and their articular surface is without constriction. Axial facets flat and subround. The axis is preserved in Nos. 1 and 3. The atlantal facets are distinct from each other, are subround, and slope at an angle of 45° with the middle line. Vertebrarterial canal complete (neural arch and extremity of transverse process lost). The floor of the neural canal is wide and flat, and is pierced by two small fomraina posterior to the middle. Inferior face flat, with a faint trace of angular keel. The centra CONDYLARTHRA. 395 of the succeeding cervicals, although slightly convex in front in vertical section, are concave in transverse section. The transverse diameter exceeds the vertical in the third vertebra more than in the sixth, where it is still, however, greater than the transverse. The inferior faces of all the centra are smooth and a little convex, and a little oblique to the vertical diameter, indicating the anterior elevation of the neck. Posterior to the third, the centra become a little concave transversely on the posterior side, but some of the epiphyses are lost. The bases of the neurapophyses are nearly round. On the fourth cervical the postzygapophysis looks almost entirely outwards. The diapophyses are round at the vertebrarterial canal, while the parapophyses are flat at the same position. The cervical vertebrae just described are from No. 3. Two proximal caudals accompany the same. The latter are robust, and have plane articu- lar extremities. They have also complete neural arches, one with, the other without, spine. The bases of the diapophyses spread anteriorly into ridges, which nearly reach the anterior edge of the centrum. Inferior face convex in the middle transversely, concave longitudinally, the convexity spreading posteriorly into two angles for base of supposed chevron bone. No. 4 ex- hibits a more distal caudal. It is large and has elongate proportions. This specimen evidently had a long tail. Unfortunately no dorsal vertebrae have been preserved. Measurements of caudal vertebra. No. 3. M. Diameter of centrum behind \ . „^^ ( transverse 016 Elevation with neural spine 019 Length of second centrum 019 „. , ■ f .(vertical 012 Diameter in front < „,. ( transverse OlS Total elevation 016 _. ^ . , , . ,< vertical 0135 Diameter centrum behind < , „,,. ( transverse 01b No. 4. Length of centrum of caudal vertebra 029 Width of centrum at extremity 025 Width of centrum at middle 012 Depth of centrum at middle 010 The glenoid cavity of the scapula is rather narrow. Its posterior bor- der is regularly rounded, while the lateral borders converge rapidly to an 396 THE PUEKCO EPOCn. apex which rises on the external base of the coracoid process. The inter- nal l)ase of the latter is excavated into a groove. The posterior face of the neck of the scapula is moderately wide, and is bounded by a groove near its internal edge. The spine rises near this edge, and far from the thin an- terior edge. Posterior to it the posterior edge is a little recurved outwards. Measurements. No. 1. u. Diameters articular face glenoid cavitv 5 ^''teroposterior 027 c transveree 018 Lfiigth of coracoid beyond face 008 Width of neck 026 Distance from glenoid cavity to spine Oil The humerus is a roljust bone with large head and condyles, and shaft contracted below the middle. The tuberosities are small, like those of the I'rohosckUa, and not produced as in the higher ungulates. The bicipital ridge is large, with a flat back and recurved edge, which is quite oblique, ending below in an angular projection, which marks the middle of the an- terior face of the shaft. Below this point the section of the shaft is trian- gular, the posterior side being the longest, and bounded externally by the external epicondylar ridge. This ridge does not develop a prominent exter- nal epicoiuh Ic. The internal fpifondyle is, on the contrary, very promi- nent. It projects abruptly from the middle of the internal condyle, and has a truncate narrow external edge, which is a little oblique to the axis of the shaft. Its superior edge rises to the shaft, and forms the bridge over a large transverse oval foramen epicondyloideum. This opens distally on the an- terior face of the humerus opposite the superior part of the coronoid fossa, and above and internal to the internal flange of the condyle. The coronoid fossa is deeper than the olecranar, and the two are separated by a thin sep- tmii. The condyles have a great transverse extent compared with their an- teroposterior; a character' more marked than in Phenacodus. The internal Hiinge is moderately prominent, and the internal roller is separated from the trochlear groove by a convexity of the surface. The trochlea is wide, and a little wider thnn tlic roller anteriorlv, and it oxpandsa little and has raised edges posteriorly. No roller posteriorly, 'i'he internal border of the troch- lea posteriorly is .sei)arated liy n deep siilirouml fossa. CONDYLARTHKA. 397 Measurements of humerus. No. 1. M. Total length with iiauge 13& Length to distal end of bicipital ridge 076 Transverse diameter of head with greater tuberosity (extended by pressure) 039 Diameters of shaft at inferior extremity of bicipital ridge \ anteroposterior 022 ( transverse 0. 15 Diameters of humerus below do J ^''^'^™P°^*«"°'^ ^^^ f transverse 018 Width at epicondyles 055 I tranverse 033 Diameter condyles anteriorly ■? < roller 015 ( anteroposterior) flange 013 Length of end of ex^icondyle 022 The ulna is stout and compressed throughout its length; its vertical diameter not diminishing much distally. The olecranon is compressed so as to be in a vertical plane ; the superior edge being acute, and the inferior rounded, and becoming wider near the extremity, where it rises obliquely inwards. The external side of the humeral cotylus is a little, the inner side more, convex. The flanges of the humeral cotylus of the ulna are peculiar. The posterior is only developed on the internal side of the shaft, and does not exist on the inner side. This is the condition in Coryphodon, but the external is present in Phenacodus and Hyrax. It is wanting in Carnivora, but the internal is smaller in them than in Periptyclms. The radial contact is entirely flat, and there is no anterior flange except on the external side. It is here horizontally extended, but not vertically, as is the case in Carnivora. There is a longitudinal groove on the external side of the shaft near the su- perior margin, which soon terminates. A much wider groove, with defined inferior edge, commences below the radial facet, on the inner side of tlie shaft, and extends along the latter, becoming wide and shallow. The radius has the proximal half of its shaft quite slender, more so than in Phenacodus primcevus or wortmani, and there is no bicipital tuberosity. The head ex- pands abruptly from the shaft, and the humeral face is transverse. It is not much recurved at the internal and wider extremity, while the external or narrower extremity is obtuse and rounded. The anterior foot is unfor- tunately unknown. 398 THE PUEKCO EPOCH. Measuremenis of ulna and radius. No. 1. . K. Length of olecranon from corouoid 030 Depth of olecranon nt middle 022 Depth of olecranon at coronoid 028 Depth of olecranon at radial facet 018 Depth of olecranon in front of radial facet 016 Width of humeral cotjlus at middle 0135 Diameters head of radinsM""*^".™* '^^ ( vertical 014 Diameters shaft of radius ^*'*"«^«™' 0^^ < vertical 008 In the other specimen, already designated No. 3, from which the cer- vical vertebrae have been described, a femur is preserved. This is a robust bone, with shaft flattened behind, and large extremities. The fossa liga- menti-teris is large. The great trochanter does not extend beyond the head, and the exterior edge is thick and strongly recurved, inclosing a small transversely deep trochanteric fossa. The little trochanter is a prominent acute convex edge. The rotular groove is moderately wide and moderately prominent. Its lateral ridges are equal. The femoral condyles are sub- equal and stand well apart. Their surface is not cut off by notches from the rotular. Measurement of femur. No. 3. H. Total length ou inner side 147 Proximal width at head 046 Transverse diameter of head 025 Width at little trochanter 031 Diameters shaft helow third trochanter ^ *'™"*^''^ *^ ( anteropostenor 014 Distal width of femtir 043 Depth at inner side of rotular groove 030 AVidth between condyles at middle 007 Sj^ecimen No. 4 exhibits a perfectly preserved third trochanter, which is broken in Nos. 1 and 3. It has one concave side and a truncate extrem- ity slightly recurved to the concave side. In Nos. 1 and 3, tibiae which have lost their epiphyses are preserved. The crest is prominent, and continues to below the middle of the shaft. At the latter point it disjjlays the peculiarity of becoming more prominent than above it, and is acute and recurved outwards, as is sometimes seen in the extremity of the bicipital crest of the humerus. Just below it the section CONDYLARTHRA. 399 of the shaft is triangular, with subequal sides, the posterior flat. The distal extremity is triangulai-, the posterior side longer than the others. This bone is long for the length of the femur and humerus. Measurements of tibia without epiphyses. Nos. 1 and 3. U. Total length (derived from two tibipe) 135 Diameter at middle of shaft J ••^°*"°P°^**^™' ^'^ transverse Oil Diameter at distal end ^''°t«'-''P°^t''"°'- ^^ ( transverse 027 The calcaneum is depressed. The border of the sustentaculum is trun- cate and not acute. The cuboid facet is transverse, wide, diamond- shaped, with opposite angles, the external angle supplemented by a promi- nent flattened tuberosity. The inferior surface has a wide external groove. Free process lost. The external inferior cotylus of the astragalus is very little concave, conformably to the form of the calcaneum. The angle at its externo-anterior termination is not produced downwards, as in Phenacodus vortmani and P. primcBVUs ; still less than in Mesonyx ossifragus. The pos- tero-internal angle is produced beyond the trochlea, but not so much as in Oxycena; its connection with the head is by a flat horizontal ridge. The head is extended laterally in both directions, so as to be wider than the neck. The median inferior or sustentacular facet is separated by deep grooves from the other facets, but is connected with the inferior recurvature of the head. The longitudinal median groove terminates posteriorly in a deep foramen penetrating upwards, and issuing in a posterior notch of the trochlear surface. This foramen is caused by the closing of the usual ten- dinous notch, and is also seen in the genus Bathmodon. The trochlea is strongly convex anteroposteriorly, though nearly flat transversely. There is a depressed fossa beneath its antero-external angle. As already remarked, this astragalus resembles somewhat that of Oxy- CPMa. It is preserved in three or four individuals. The navicular is rather shallow, and is wider transversely than anteroposteriorly. Its median facet is the largest, and rises highest in front. The cuboid, which is also pre- served in No. 1, has a square anterior face. Its proximal face is convex anteroposteriorly, and the distal face is concave anteroposteriorly to a less 400 THE PUERCO EPOCH. degree. There is a short lateral focet on the inner side for the navicular. The extemal tendinous tuberosity is prominent, and extends across the infe- rior face of the bone. The front of the ectocuneiform is slightly oblique ; it is half as high again as wide, and has a low tuberosity near the internal proximal corner. Posterior tuberosity large. The metatarsals are short. The third aiul fourth are of equal lengths; the second is a little and the first much shorter. The proximal extremity of the fourth is externally con- cave for the head of the fifth. There are no deep transverse grooves above the distal condyles These are rather narrow, and have a short posterioi" heel. The distal faces of the phalanges are infero-posterior, but on the plialangines they are somewhat recurved. The lateral ligamentous fossae are moderate. The phalanges are slenderer than is usual in ungulate mam- malia, and resemble those of some carnivora. They are move depressed than in these animals, and resemble most those of Mesonyx. The distal extremities of the metapodials, though narrow, display no tendency to the convex form seen in carnivora. It is evident from the propox'tions of the posterior feet in the two speci- mens preserved, that these members are relatively small in the Periptijclms rhabdodon. It is also evident that they were wide and flat and plantigrade; more so than in the species of Phenacodus. Measurements of posterior foot. No. 1. M. Width of calcanenni at snstentacnlum 026 Diameters 8n8tentacular facet ^""♦«^''P''«*«"°'" 0^3 ( transverse 013 DiHtal width of calcanenni (134 Diameters cnboid facet ^ ''^'^'"'''^ 01^' < transverse 017 Astragalns; greatest l'''"St'> O^^* *■ ' *• \ width (»-ja ( length 010 Trochlea of astragalus; KreatCHt < width 023 ' height, externally 014 Head of astragulns, greatest J '^"*"' ^-"^ ( litight 012 Length of third metatarNal 050 1 ]>ruxiuiully auteroposteriorly 015 Diameter of third raetatarsau medially transversely 009 ( at distal fossa; transversely 0135 Length of fourth metatarsal 046 CONDYLARTHRA. 401 M. Anteroposterior width of head of fourth metatarsal 0135 Width of first metatarsal at middle 007 Length of cuboid in front 019 Width of cuboid in front 0165 Diameters distal facet l«'^^«^°P°«t«"'"" "^^ ( transverse 014 No. 4 (large form). Diameter shaft humerus at middle 016 Depth head of radius 013 Width calcaneum at sustentaculum 026 Width navicular 018 Length navicular 007 Length ectocuneiform 012 Width ectocuneiform 009 Depth ectocuneiform 019 Length of a short metatarsal (? iv) 030 Depth of the same metatarsal proximally 015 Width of the same metatarsal dislally 012 Length of phalange of M. i or ii 019 Width of phalange distally 008 Length phalangine of M. i or ii Oil AVidth proximally 009 Width distally - 007 Length astragalus of a second specimen -. 027 Width of trochlea 019 Elevation externally 013 Brain. — The cast of the middle part of the brain-case ah-eady men- tioned (p. 388) presents interesting characters. The cerebral hemispheres are very flat, and are only differentiated from the olfactory lobes by a mod- erate contraction and depression, which forms the peduncle of the latter. Only the proximal part of the olfactory lobe is preserved, but this expands so as to be only a little narrower than the hemispheres. The peduncle has a ridge on the median line, and a shallow fossa on each side of it. The lat- eral outlines of the hemispheres diverge, and the widest part is posterior. There is no indication of sylvian fissure. The transverse section of the hemispheres would be a flat arch but for the presence of a longitudinal oval protuberance on each of them, which do not quite touch the median line, and which have definite boundaries. If their limits determine the size of the cerebral hemispheres, then the latter are wider than long, but they probably pass gradually into the mesencephalon behind them. These bodies remind one of the corpora olivseformia, and may i-epresent the supe- rior or median frontal convolutions. They are probably, however, not to 26 c 402 THE PUERCO EPOCH. be honiologized with any convolution, representing rather the cerebral vault of the lateral ventricle. Posterior to them the flat surface descends gently without indication of corpora quadrigemina or other irregularity, and at a distance about equal to the length of the oval bodies, begins to rise gently. The cranium is broken here, and no cast of the cerebellum was obtained. I may remark that the cranium from which this cast is taken is not crushed, and that it consists of parts of the parietal and squamosal bones only. The latter remain as far as the incurvature to the pterygoid pro- cesses in front of the glenoid cavity. MeasurementH of brain. M. Length from posterior rise to base of olfactory lobes 037 Length of oval bodies of hemispheres 018 Width iif proximal part of olfactory lobes 027 Width of olfactory peduncles 021 Length from olfactory lobes to oval bodies of hemispheres 005 Diameter of hemispheres at posterior p.art of oval bodies 038 Depth from sagittal crest to olfactory lobes 024 Restoration — This remarkable animal was about the size of the col- lared peccary, though the skull was perhaps a little larger. It must have had a peculiar appearance, and unlike that of any known mammal. The long legs with plantigrade feet must have given it the form of a bear, but its very short neck is only paralleled by that of the elephant. Wliile the shorter legs forbid near resemblance to that animal, and the shape of the head is very different, yet the resemblances in the figure cannot be over- looked. It had a long tail, stout at the base. It was a smaller animal than the Phenacodus primcevus, but the head was of near the same size. The dental system does not furnish any weapons of offense or defense, and none are known from any other part of the skeleton. Its habits were omnivor- ous, judging again from dental characters. It is the most abundant mam- mal of the Puerco, and to this time the largest discovered. The large variety already mentioned is less abundant than the typical form, three individuals only having been sent by Mr. Baldwin. The speci- mens are frequently weathered from the rock matrix so as to be in beautiful condition. CONDYLARTHRA. 403 Periptychus carinidens Cope. American Naturalist, 1881, March, p. 337. Paleontologlcal BuUetiu No. 33, p. 484, Sept. 1881. Plate XXV n, fig. 16; XXIII l^ ( traiiHvorso iXH.t5 Diameters M.i^•'"t"-"■"l"""«"'"• '^••''' I trausverse (MI'JO Depth of ramus maudibuli at M. ii 0130 No. 2. Diameters Pm. jj ^ ""teroposterior 0050 { transverse OOCO Diameters M. iii J ''"'"°l"»'t«"''r 0"^' I. iii \ ""'""l ( trausvj jrse 0070 Length of base of inferior Pm. ii 0050 Depth of ramus at inferior Pm. ii 0100 Diamctore inferior M. (j U"teropoHtorior 0045 < transverse 004o Length of base iii COKDYLARTHRA. 411 Both of the specimens of this species were found in the lowest Puerco beds of New Mexico by Mr. D. Baldwin. Anisonchus gillianus Cope. Proceed. Amer. Pliilos. Soc, 1882, p. 467; Saploconusgillianus Cope, American Naturalist, 1882, p. 686 Plate XXV/; figs. 10-11. This animal is the smallest of the family of the Periptychidce which is yet known. There are parts of five individuals in my collection which in- clude the dentition of both jaws exclusive of the most anterior teeth. Two of these consist of fragments of the lower jaw only. Two others include parts of both jaws, and one includes only the right maxillary bone with teeth. The typical specimen displays the second and third superior premolars and first two true molars, with the second and fourth inferior premolars, and last two true molars. The fourth superior premolar is lost from this specimen, but I exposed it in a second one, after removing the decidious tooth which preceded it. The second superior premolar has but two roots, the anterior and interior being fused. The section of the base of the crown is a spherical triangle with the apex anterior. It has a low cingulum except at the external base. The apex of the crown is compressed so as be a fore and aft edge. The third superior premolar is similar as to its external cusp, which is larger than that of the second. The internal cusp is three-quarters the height of the external, and the apex is compressed so as to be antero- posterior, The diameter of its base is only lialf that of the external cusp. There is a cingulum which is weak externally and wanting internally. The second true molar has greater transverse extent than the first or fourth. The external cusps are slightly convex externally. The V is not produced inwards, while the posterior internal cusp does stand well inwards, its base being especially prominent. It is posterior to the middle line, though entirely interior to the apex of the V. Besides the posterior cingulum, the strong anterior cingulum reaches nearly to its anterior base. The third true molar is equal to the first. In the inferior series the second premolar has a small anterior basal tubercle, a robust acute median cusp, and a small heel whose outline is a ' circular ridge. The fourth premolar is like the second, but all the parts 412 THE PUEKCO EPOCH. are larger. The true molars have the crown contracted upwards from the base. The cusps are rather elevated, the anterior the most so. The ante- rior median is nearly as high as the anterior inner, and like it, is connected with the anterior external by a thin ridge, the two forming a V. The pos- terior cusps are connected by a continuous edge, in which the posterior median is barely distinguishable. On the last molar, however, it forms a large and prominent fifth lobe. The cingula are very rudimental. Enamel smooth. In the second specimen the crown of the fourth premolar was exposed after removing the temporary molar from above it. The internal crest is like that of the corresponding tooth in the A. seetorius, continuing into a wide cingular ledge at the anterior base of the external cusp. The supe- rior true molars of this specimen have the general form of those of the type, and differ from those of the A. seetorius. They liave, however, a stronger external cinffulum than those of the latter. This character is seen to be still more marked in the third cranial specimen, where the cingulum is more produced at the interior and posterior angles of the crown. In the specimen the external faces of the external cusps are quite flat, and on the second true molar their apices are inclined inwards. Specimen No. 2 is intermediate between 1 and 3 in this respect. It is quite possible that Nos. 2 and 3 belong to a species distinct from No. 1, and if this is the case they must be regarded as the types of Anisonelms gillianus, as the first descrip- tion of the species was first principally drawn from them. The inferior first true molar of No. 2 differs from that of No. 1 in the smaller size of the anterior inner and anterior median cusps, and in the larger size of the pos- terior median. Another inferior molar i.s intermediate between the two. The temporary fourth premolar of both jaws is preserved in No. 2, and of the superior series in No. 3. That of the superior series resembles a true molar more than it does its successor. In fact, it is identical with the true molars, excepting in the smaller size of the internal cusp, which is only a little posterior. The external cusps differ from eacli other ; the anterior is erect ; the inner is a little inclined inwards, forming a V. Its appearance reminds one of the permanent first true molar in Coryphodon. The last inferior milk molar only differs from a true molar in the smaller CONDYLAETHEA. 413 size of the anterior inner and anterior median cusps, and the greater ante- rior prolongation of the anterior lobe. It differs from its successor much as that of Trnsodon quivirensis does its successor, and resembles the perma- nent fourth premolar of such types {Didelphys, e. g.) in which that tooth resembles the true molars. This specimen shows the anterior cusp of the third and fourth permanent premolars. MeastiremenU. No. 1. M. L,ength of last six superior molars (Pm. iv estimated) 023 Length of true molars 0112 Width of base of Pm. ii 0038 Diameters Pm. iii ^'^"t''"'"!"'^*"'"'' ■•■ 'ff^ ( transverse 00o2 Diameters M. ii ^ '^"^•'^"P"^""'"' Zf'- c transverse OUoo Diameters base of M. iii ^ ='°t""P''«t<'"°'- '^'^'^^ ( transverse : Wi'^ Length of last four inferior molars (M. i estimated) 0175 Length of base Pm. ii 0040 T>. i T3 ■ (anteroposterior 0050 Diameters Pm. iv < ' I transverse U03o Diameters M. ii ^'^""^™P°«*'^""'^ llf^ ( transverse 0034 Diameters M.iii^^'"''^»P''»*''"°'^ l^^'l i transverse UU35 Depth ramus at M. ii 0090 • No. 2. _. , • 1 -J Ki • S anteroposterior 0040 Diameters superior deciduous M. IV ^ ^ „^,^ C transverse (JU40 _. . 1. -Kr ■ (anteroposterior 0040 Diameters permanent M. i < ' „.„„ ( transverse UUbU Length base inferior deciduous M. iv 0041 Length base inferior permanent M. i 0044 This species is dedicated to my friend, the distinguished zoologist, Prof. Theodore Gill, of Washington. Its horizon is the lower Puerco beds, where it accompanies the Haploconus entoconus. D. Baldwin. Anisonchus sectoeius Cope. Mioclainus sectorius Cope, American Naturalist, 1881, p. 831 (September 22). Anisonchus sectorius Cope, Paleontological Bulletin No. 33, p. 488, September, 1881. Proceed. Amer. Philos. Soc, 1881, 488. Plate XXV c ; figs. 5, 6, and 8. This species is known from the maxillary bones with teeth of five indi- viduals ; two accompanied by mandibles with teeth, and by a number of 414 THE PUERCO EPOCH. separate mandibular rami. The third and fourth superior premolars cover a larger base than either of the true molars. The external cusp has a base extended anteroposteriorly, but the apex is conical, and there are no basal tubercles. The inner cusp has a crescentic base, as in Periptychus, but the apex is narrowed and compressed conic. The external tubercles of the true molars are subconic, and do not develop any external ridges. Thev are connected by the crescentic slightly angular crest, or V, whose apex forms the inner anterior boundary of the crown. This crest is not divided into parts homologous with the intermediate tubercles. The crowns of the M. i, ii, and iii are surrounded by a basal cingulum, which in the M. i develops a tubercle at the anterior external angle. The posterior inner lobe is more posterior in this species than in any of the others, and has a V-shaped apex. It projects further inwards than the anterior inner lobe. It is repre- sented by a mere tubercle of the cingulum in Mioclcenus. No internal or external cingulum on Pm. iv. Enamel nearly smooth. The ranms of the mandible is rather slender anteriorly. The Pm. iv is robust, and the cusp is above the middle of the base of the crown. Me- dian anterior tubercle small, but distinct. The heel is short and narrow, and has a raised border, connected with the base of the main cusp. Tlie cusps of the true molars are elevated and conic, the anterior the highest, and others subequal. The base of the posterior pair is a little narrower than that of the anterior pair. There is no central tubercle as in Perip- tychus rhahdodon, and no basal cingulum on any tooth. Diameters superior Pu.. iv \ ""teroposterior. ( transverse Meusurements. M. Lcngtb of three superior molars 0160 0055 0070 Diameters superior M.i J ""tcroposterior 0052 ( transverse 0060 Length of inferior molar series 0010 Length of inferior true inohir series 0160 terior 0060 0040 Diameters inferior Pm. iv^ anteroposterio ( transverse Diameters inferior M. ii $ anteroposterior IH.r.O ( tninsverso 0040 Depth ramus at M. ii 0090 A number of minor points will distinguish this species from those included among the Mesodonta, and also from those oi Pantolestes, whii-h it CONDYLAETHEA. 415 much resembles. The molar teeth are narrower behind, and the fourth pre- molar is larger. From the Puerco beds of Northwestern New Mexico. Discovered by D. Baldwin. HAPLOCONUS Cope. American Naturalist, 1882, p. 417 (April 25). 1 4 3. Dental formula: I.?; C. -r; P-m. — ; M. -^ ; no diastemata. Canines well developed; superior first premolar one-rooted; third superior premolar a flattened cone, without accessory crest or cusp; fourth superior premolar with crown of an external cusp, and an internal crest, as in the genera just preceding. Superior true molars with crowns consisting of two external cusps, a median V directed inwards, and a distinct posterior internal cusp. No other cusps of superior molars. Inferior premolars without internal tubercle or cusp; the first one-rooted. True molars with four tubercles in pairs, and a posterior median tubercle. Anterior median tubercle present or absent. Third inferior true molar with a heel. Angle of mandible not inflected or reflected. The skeleton of this genus is unknown. The true molars of the supe- rior series are those of Anisonchus, but the third premolar is entirely diifer- ent. Some of the species are distinguished by the absence of the anterior median tubercles of the inferior true molars, while others possess it. I can- not divide them into two genera on this account, as the tubercle in question is sometimes very small, and in some cases indistinguishable. Besides this, the species differ like those of Anisonchus, in the form of the internal tubercle of the superior fourth premolar. In the one group it is a cone; in the other a crest, or strong cingulum rising into a cone. This will also prob- ably prove to be an evanescent character in some species not yet discov- ered. An intermediate form is seen in the fourth superior premolar of the Anisonchus coniferus; and the two forms are displayed in a less typical con- dition in the two species of Protogonia. The four species are all known from their mandibular rami, and the 416 THE PUERCO EPOCH. Buperior molar series of two of thein is known. The distinctive characters of the former are as follows: I. No anterior median tubercle of inferior true molars. a. Fourth inferior premolar robust. Leujith of last four molars M. 018; of true niolais ii and iii, .0082 H. angitstus. LiiU'^lh of last four molars, .OJl'; of true molars ii and iii, .010; third and fourth pre- molars equal E. lineatus. aa. Fourth inferior jireinolar compressed and sharp. Length of last four molars, .020; third premolar shorter than fourth H. xiphudon. II. Anterior median tubercle present. Anterior median cusp smaller; last four molars, .024; true molars ii and iii, .0115; largest H. entocomis. The characteristics of tlie superior molars of two of the species are as follows : I. Internal lobe of fourth superior premolar crest-like and concentric. True molars less transverse; length .012; ])remolars striate H. lineatus. II. Internal lobes of fourth i)remolar conic. Time molars more transverse; length, . 0145; premolars smooth H. entoconus. All the species are from the Puerco Eocene. Haploconus angustus Cope. Mioolcenut angiutua Cope. American Naturalist, 1881, 831, Sept. 22. Paleontological Bulletin No. 33, p. 491. Plate LVII/; fig. 6. The least species of the genus, with the teeth about the size of Hyopso- dus pauhts Leidy, but with more robust jaw. The molar teeth diminish in size regularly posteriorly from the P-m. iv. They all have three subequal pos- terior cusps which are less elevated than the anterior ones. The median is enlarged into a heel on the last tooth. The anterior are opposite, and the external is larger than the internal. There is no anterior internal. The external wears into an anteroposterior narrow grinding surface, which looks like a combination with an anterior median. The latter is, however, not separate on the least worn molars. The anterior outer cusp increases in size anteriorly, and is the large cusp of the P-m. iv. It sends a branch backwards on the inner side of the crown which forms the edge of the nar- row concave heel. There are no cingula except a short one on the anterior corners of the base of the crown of the P-m. iv. Enamel obscurely wrinkled. CONDYLAETHEA. 417 Measurements. Length of posterior four molars 0180 Diameters of P-m.iv J '^°t«r°P°«*«"°^ O^f i transverse . 0035 Diameters of M.i,<«°t*'™P''«^<'"<"^ ^^^ i transverse 0035 Diameters of M.ii^"''*^^"!"'^*''"'"" "^t!! < transverse 0032 Diameters of M.iii^''"*'"™P"^t«"'"' ^045 ( transverse 0030 Depth of ramus atM. 1 0110 Thickness of ramus at M. i 0060 From the Puerco beds of Northwestern New Mexico, one specimen found by D. Baldwin. HOPLOCONUS LINEATUS Cope. American Naturalist ISH'i (May), p. Plate XXV e; figs. 1-4. This species appears to have been more abundant than the other spe- cies, Mr. Baldwin having sent me parts of fifteen individuals. Two of these include parts of crania, the best preserved lacking the posterior half of the brain-case and the extremity of the premaxillary only. It is somewhat damaged anterior to the orbits, so that some of the foramina cannot be seen. In this species the predominant size of the premolars, seen in all the species of this group, is restricted to the fourth in the superior series, and the third and fourth below. Alveolae of two of the superior incisors are preserved. The canines have a vertical position. The second premolar is two-rooted. The third premolar has the posterior root wider than long, but not divided into two. The fourth premolar has three roots. The crown of the third is compressed so that the apex wears into a narrow anteroposterior oval. The internal crest of the fourth premolar is large, and is extensively visible back of the external cusp when viewed from the side. The external cusps of the true molars are somewhat flattened, the posterior more so than the anterior. The internal V is more open, and thus less prominent inwards than in the Anisonclius sedorius. The posterior internal cusp is more prom- inent and acute than in that species, and it is continuous with a posterior cingulum which extends to the base of the posterior external cusp. An an- terior cingulum which only extends to the base of the angle of the V. A weak external cingulum on the second and third true molars; a slight one 27 0 418 THE PUEECO EPOCH. on the untero-external part of the P-m. iv, and a weak one on the anterior half of the P-m. iii. Enamel smooth on the true molars; weakly striate on the external side of the P-m. iii and iv, and more strongly striate on the inner side of the P-m. iv. The mandibular ramus is compressed and rather deep. The condyle is well above the level of the crowns of the molars, and its articular face on its inner half (external unknown) looks upwards. The coronoid process is large, and rises close anterior to the condyle, and is in the plane of the angle. The latter is mostly in a vertical plane. Its inferior border is de- curved, and then recurved to an apex, which projects a little posterior to the line of the condyle, and is a little incurved. The masseteric fossa is defined anteriorly to the middle of the depth of the horizontal ramus, but below that point definition i.s wanting. The inferior canine is rather abruptly recurved. There is no diastema behind it. The crown of the second premolar is rather elevated, ifi com- pressed, has a posterior acute heel, and a vertical anterior outline without basal tubercle. The third premolar has the same characters, except that the heel is truncate behind, and has an inclosed fissure above. The fourth premolar is more robust, and has a wider heel whose basin is open on the external side. There is no anterior basal tubercle, but a low ciuguluni extending from the inner base of the principal cusp. As in the other premolars this cusp is compressed, and it has a fi-ee postero-external edge. The second true molar is a little smaller than the first or third. The cusps of the anterior pair are closely connected, and the anterior ridge of the internal one descends to the base, and forms an anterior cingulum which turns back to the anterior external base of the external cusp. The internal anterior cusp also has a sharp posterior edge which joins a corresponding edge of the external posterior cusj). All of the cusps are rather acute. A cingulum descends from the posterior median cusp and extends to the pos- terior base of the anterior external cusp. It is most prominent on the hist molar, where the posterior cusp forms a prominent heel. The edge-like compression of the anterior inner cusp is most marked on the first true molar, and least marked on the third. The portion of skull preserved shows a moderately elongate muzzle, CONDYLARTHRA. 419 somewhat compressed between the canine alveoli and the bases of the malar bones. The orbits are rather small and are open posteriorly. There is an obtuse postorbital angle of the frontal bone, and sharp temporal angles originate from these and converge posteriorly, and probably form a sagittal crest; but this part is broken off. The infraorbital foramen is above the posterior part of the third superior premolar. The frontal bone is convex downwards to the postfrontal angles, but is concave medially. Measurements. No. 1. Length of posterior five superior molars 0226 _. . .1 • J 1 < auteroposterior 0045 Diameters third premolar^ . '^ „,„ I transverse 0040 Diameters fourth premolar I '»°"'^°P°«**^"*^'- ^"^^ ( transverse 0055 Diameters first true molar ^^°*«"^°P°«t«^'°^ 0^45 > ( transverse 0058 Diameters third true molar J ••'°**'^°P°«t«"'"- ^^^ I transverse OOoo No. 2. Length of posterior five superior molars 0220 Length from canine to M. iU inclusive 0340 Long diameter base of crown superior canine 0050 Width between postorbital angles 0260 Length base of inferior P-m. ii 0045 Length base of inferior P-m. iii 0070 Width base of inferior P-m. iv 0040 Diameters M.i I ^°t«'*'P°«*«"<"" ^^^ I transverse OUdO Diameters M.ii^''°'«^°P°«*«"<"" ^^° < transverse .OOdo Length M. iii 0052 Depth ramus at P-m. iii 0100 Depth ramus at M iii 0145 No. 3. Length of ramus from canine to edge of angle 0760 Depth ramus at M. iii 0155 Elevation of condyle above base of ramus 0300 Anteroposterior width base of coronoid 0220 The compression and enlargement of the external anterior cusp of the inferior true molars is a peculiar feature of this species. It is perhaps ho- mologous with the crest which extends from this cusp to the anterior median in the Anisonchus gillianus. It suggests a more or less carnivorous habit for the species. From the upper Puerco beds of Northwestern New Mexico. 420 ' THE PUERCO EroOH. This animal is a little larger than the Anisonckus sectoriits, and about equal in the size of its skull to the gray fox. Haploconus xiphodon Cope. Proceed. Ainer. Philos. Soc, IStftJ, p. 466. Plato XXV e; figs. 5-6. This species is represented by a mandibular ramus and perhaps by three rami. The one on which the species rests contains five molars, the middle cue of the series broken, so that its form cannot be positively ascertained. It is probable that it is the first true molar, so that the animal exhibits the last true molar not entirely protruded, and is therefore nearly adult. But there are some reasons for suspecting the animal to be young. Thus the last inferior molar does not exhibit more of a heel than the second u.sually does, and the supposed third jjremolar is smaller than that tooth is in the other species, having nearly the proportions of the second premolar. The teeth present may then be supposed to be the molars from the second to the sixth inclusive. But opposed to this view is the fact that the supposed third premolar has more the structure of that tootli in details tlian that of the second, and the specimens accompanying, which have the temporary den- tition apparently of the same species, present premolar teeth of a very different character. In any case the present specimen represents a third species of the genus, and I describe it at present as an adult. The third premolar has a simple, compressed crown, about as high as the length of its base, and without anterior basal tubercle. It has a narrow triangular posterior face which is concave, and truncated by a cingiilum below; no heel proper, nor lateral cingula. The fourth premolar is an elongate tooth consisting of a compressed principal median lobe, an anterior loVje connate with it, and a heel. The latter has elevated posterior and interior borders. A rudiment of an exterior border is seen in a narrow ridge on the external side of the posterior face of the principal lobe of the tooth. The sides of the premolars present rather distant ridges, as in Periptychus carinidens. The second true molar has two anterior and three posterior tubercles; the latter close together, pointed, and of about equal size. Of the anterior tubercles the external is much the larger and more elevated. It is compressed, and has a curved subacute anterior edge, which CONDYLAETHRA. 421 extends much in front of the internal tubercle. There is no anterior inner tubercle, nor are there any cinguki. The enamel of the sides of the croATO presents a few vertical ridges. The last inferior molar only differs from the second in the greater size of the median posterior lobe, which is nevertheless smaller than in the two other species of Haploconus. There is a mental foramen below the posterior edge of the alveolus of the second inferior premolar. Measurements. M. Length of last five inferior molars 0250 Length of third premolar 0050 Length of fourth premolar 0066 Length of second true molar 0050 Width of second true molar 0032 Length of third true molar 0050 Depth of ramus at Pm. iii 0095 Depth of ramus at M. iii 0130 The two rami witli the temporary premolars exhibit the last true molar, inclosed in the jaw. The third and fourth premolars are much like the fourth premolar of the specimen above described, but the foui-th is a little more robust than that of the latter, which is very much like the third of the deciduous series. The space occupied by the supposed first premolar of the type specimen is too short for the fourth premolar of the deciduous series, otherwise it might l)e supposed to have occupied that position. The two true molars resemble those of the type, excepting that the last one does not extend so far into the base of the coronoid process, and its posterior lobe is smaller, in accordance with its position as No. two in the series. The specimens were procured by Mr. D. Baldwin in the Puerco beds of New Mexico. Haploconus entoconus Cope. American Naturalist, 1882, p. 686. Piute XXV/,- figs. 4-5. This is the largest species of Hcq)Joco)ms, and repi'esents a group in it slightly different from that which is typical. Mr. Baldwin has sent me frag- ments of the skulls and jaws of seven individuals, so that its molar dentition is entirely known. The premolars are more robust than the molars in this species. The third of the superior series has a subti'iangular base, with broadly rounded angles. The crown is absolutely simple, the apex having a nearly round sec- 422 THE PUERCO EPOCH. tion. There are traces of anterior and posterior cingula. The base of the fourth superiorpremolar is more extended transversely, to sustain the conical internal cusp. The external cusp is but little longer than wide Traces of anterior and posterior cingula, which are not connected with the internal lobe. The ex- ternal cusps of the superior true molars are not fl.attened on the external side, and have a subround section. The internal V is not very prominent inwards, and is uninterrupted. The internal cusp rising from the posterior cingulum is large, and is a little posterior to median in position, and its base projects well inwards. The last molar is a little smaller than the others, and the extern.al face is oblique. All the true molars have an external cingulum, which extends into the anterior limb of the V in front, and posteriorly rises to the posterior external cusp. The posterior limb of the V descends to a posterior cingulum. The internal cusp descends to both anterior and pos- terior cingula, of which the latter is the stronger. The alveolus of the inferior canine indicates a large tooth directed at an angle of 45° forwards. The first premolar has a single stout root. The second premolar is two-rooted, and has a subconic crown with a rudi- mental heel behind. The third and fourth premolars are similar to it, dif- fering in their increasing size, and the transverse extent of the small heels. None of them have anterior tubercle or cingulum, as in the other species. In all of them the heel of the fourth inferior premolar tooth is longer than in n. rntoconns. The inferior true inuhus are of robust form, subequal in size, and smaller than the last two premolars. They have three posterior, three an- terior, and no central tubercles, and of these the median posterior and an- terior are the smallest, except on the third molar, where the posterior forms the robust heel. The lateral posterior are the apices of externally directed angles of the summit of the crown, and are less elevated than the principal anterior. These are opposite and are fused at the base. The external is more elevated than the internal. The true molars all have a trace of an- terior cingulum, and a trace externally between the cusps. The only in- ternal cingulum surrounds the base of the anterior tubercle, on the second and third true molars. The enamel of all the teeth is smooth, except a faint striation on the superior premolars. CONDYLARTHEA. 423 The symphysis mandibuli extends posteriorly to below the anterior margin of the third premolar. The inferior border of the ramus is greatly convex. The border of the masseteric fossa is only distinct on the anterior edge of the coronoid process. There is a small meatal foramen below the first premolai'. The infraorbital foramen is above the posterior part of the third premolar. The malar bone does not extend anterior to the base of the zygomatic process of the maxillary, excepting in a narrow prolongation forming the external edge of the inferior border of the orbit. This pro- longation rises on the anterior border of the orbit to a point considerably above the line of the infraorbital foramen. Measurements. No. 1 {superior molars). M. Leugth of bases of last five superior molars 026 Length of superior true molars 014 Diameters of p.m. iii J *"*<'™l«'«t«'i°'^ 0065 ( transverse 007 Diameters of P-m.iv^''"t"''P''«t''"°'' 0055 c transverse 008 Diameters M. i^'^°*''^°P°«*«'"'''' ' 005 ( transverse 0086 Diameters M.iii J ^■^t*''°P'"**°"°' 0035 c transverse 008 No. 2 (both jaw$). M. Length of last tive superior molars 0275 Length of superior true molars 014 Length of last five inferior molars 029 Length of inferior true molars 0155 Diameters M.i^^"**^''?"^*^"'"^ ■ 0055 t transverse 045 Measurements M.iii^'»«*^'-°P°^'«"°' 0055 transverse 0038 Depth of ramus at M. ii 0146 No 3 (Inferior Molars). M. Length of inferior molar series 0410 Length of inferior true molars 0175 Length of base of P-m. ii 0054 Length of base of P-m. iii 0068 Width of base of P-m. iii 0050 Length of b.ase of P-m. Iv 0068 Width of base of P-m. iv 0050 This species has only been found as yet in the lower part of the Puerco formation, by Mr. Baldwin; as the S. lineatus has been only obtained from the upper Puerco. 424 THE PUERCO EPOCH. PROTOGONIA Cope. Paleontologic.ll Bulletin, No. 3:{, p. 492, Sept. 30, 1881. Proced. Amer. Philos. Soc, 1881, p. 4"J2. Fourth superior premolar with one external and one internal lobe. Ti-ue molars with two external, two internal, and two intermediate lobes, both the latter connected with the anterior internal by a ridge. Supposed inferior true molars with two V's with weak anterior branches; last true molar with heel. Fourth inferior premolar with internal cusp. In the superior true molars the anterior transverse crest of the Hyra- cotherium is represented, but not the posterior. This is replaced by a low ridge running across the course it pursues in Hyracotherium. The posterior median tubercle is also not found in the latter genus. Protogonia differs from Limuohifus in the subconic character of the external lobes of the su- perior molars. If the tubercles, excepting the posterior inner, should be converted into crescents, the genus Me)mcotherium would be produced. It probably represents the ancestral type of the Meniscotheriidai. The simple premolars give it a position nearer the Periptyckidae than that occupied by Phenacodus. Xx\ approach to it is made by tlie Phenacodus puercensis of the same geological horizon. Two species of Protogonia are known to me. Protogonia plicifera Cope. Ameticau X.itiirali.st, lr<82, p. 833 (Sept. 28). Plate XXV/; lij;s. 2-3. This species, although not the first described, is most expressive of the characters of the genus. The external lobe of the fourth superior premolar is absolutely simple, as in most Artiodactyla, while in the P. subquadrafa there is a minute rudiment of the second or posterior external cusp, which is well developed in Phenacodus. A single individual is all that is known of the species. This is represented by a maxillary bone, which contains the fourth premolar, and anterior two true molars, and the accompanying mandibular ramus, which supports the three corresponding inferior teeth. This species is smaller than the P. subquadraia, and differs from it es- pecially in the form of the internal cusp of the fourth snj)erior true nitjar. In this species it is the apex of a V, whose limbs form tlie anterinr and posterior cingula. In P. subquadraia it is a simple cone, disconnected from CONDYLARTHRA. 425 the cingula. Between it and the internal side of the base of the external cusp is a rudiment of the anterior intermediate tubercle. No posterior intermediate tubercle. The external face of the external lobe of the crown is flat. The anterior and posterior cingula terminate externally at the an- gles of the crown, the anterior rising into a prominent angle. Internally they extend to near the internal border of the crown, but do not pass round it The external cusps of the true molars are conical, as are the smaller intermediate tubercles. The anterior internal tubercle is the apex of a V, and is larger than the posterior internal. The latter is well developed, and is a cone. A distinct cingulum extends round the crowns except on the inner side. It rises to an angle at the anterior external corner of the crown. The first and second inferior true molars support six cusps, three pos- terior and three anterior. The three posterior are arranged round the pos- terior raised edge of the crown. The three anterior are two internal and one external. The last is the largest, and the anterior internal is the smallest, and is close to the posterior internal. The latter is a little behind opposite to the anterior external, and is connected with the posterior external by a low oblique ridge, thus completing a V- The three anterior tubercles are connected by ridges, and form on wearing, a narrow trans- verse U' No cingula. The fourth inferior premolar has a short, wide heel, with reverted edge and a large principal cusp. On the inner posterior side of the latter is the internal cusp, closely connected ; and at the anterior base is a prominent tubercle, inside the longitudinal axis of the principal cusp. No cingula. Last true molar unknown. Measuremeyits. M. Length of superior P-m. iv with M.'s i and ii 0215 < anteroposterior 0060 Diameters p.m. iv 5 t^^^^^^jgg O^.g P-ni. iv I Diameters of M < anteroiiosterior 007 ■ " { transverse , 0095 Length of inferior P-m. iv, with M.'s i and ii 023 „. . o • S iiuteroposterior 007 Diameters P-m. IV ^ ' ( transverse 0046 S anteroposterior 0075 Diameters of M. i ^ ^^.^^g^^^^g g^g Puerco formation of New Mexico, discovered by D. Baldwin. 426 THE PUEllCO EPOCH. Protogonia subquadrata Cope. Paleontological Bulletin No. 33, p. 493, IS-^l. Proc. Amer. Philos. 8oo., 1881, p. 492. Plate LVII/; figs. 11-12. Probably two specimens; one supporting three superior molars; the other including damaged superior molars, and the last two inferior molars. The pertinence of the latter specimen to this species is doubtful. The animal was about the size of the red fox. The external cusp of the fourth superior premolar is flattened externally, and has a small lobe on its pos- terior edge. The inner tubercle is conic and is separated by a tubercle from the anterior base of the external. True molars without external ridges. The external cusps of the true molars are lenticular in section. The posterior inner cusp is in nearly the same anteroposterior line with the anterior, its section about equaling that of the intermediate cusps. The first and second molars have an external, an anterior and posterior, but no internal, basal cingula. The enamel is somewhat wrinkled where not worn. The heel of the last inferior true molar is elevated, and its worn surface forms the extended posterior branch of the posterior V- The posterior edge of the penultimate molar is elevated and curved forwards on the inner side of the crown. The anterior cusp forming the angle of the V of this tooth is higher than the posterior angular cusp, but the anterior limb descends rapidly as in Coryphodon. A weak antero-external, and postero-external cingula. Enamel wrinkled where not worn. Measurements. No. 1. M. Length of base:) of three superior molars 025 _. ^ , . _ . (anteroposterior 0006 Diameters of superior P-ni. IV < ' „^^_ ' < transverse 0086 _. . , • xf (anteroposterior (XXS.') Diameters of superior SI. i < ' ( transverse Oil _,. . - • nr •• ( auti'ioposterior 009 Diameters of superior JI. ii < . ' t transverse Oil No. 2. Length of bases of last two inferior molars 0225 Diameters of last inferior molar J "" "^"^°* "^ " „,.. < tr.insverse OOoC CONDYLARTHEA. 427 M. Diameters Of inferior M.n^''°t«^«P''«*«"'"^ O"'^ ( transverse 0080 Depth of ramus at M. ii 0*^40 Thickness of ramus atM. ii 0110 From the Puerco beds of Northwestern New Mexico. Discovered by Dr. Baldwin. ANACODON Cope. Paleontological Bulletin, No. 34, p. 181, Feb. 20, 1882. Proceed. Amer. Philos. Soc, 1881, p. 181. Char. gen. Known only from mandibles supporting molar teeth. Probably family Phenacodontidoe. Last inferior molar with heel. Crowns of molars without distinct cusps, but with a superior surface consisting of two low transverse ridges separated by a shallow valley. Unworn grind- ing surface with shallow wrinkles. Perhaps only three premolars. The only species known is from the Wasatch epoch. Anacodon ursidens Cope. Loc. sup. cit., p. 183. Plate XXVe; fig. 11. Broken mandibular rami of two individuals constitute the basis of my knowledge of this species. It is of the size of the Phenacodus primcevus. The last inferior molar is wedge-shaped with the very obtuse apex posterior. It displays two slight transverse elevations anteriorly, winch represent the usual cusps. Grinding surface generally nearly flat. The posterior half of the crown of the penultimate molar is flat, and is separated from the ante- rior half by a transverse groove. Its surface is marked by shallow branch- ing grooves. The molar preceding this one in the broken specimen is probably the first. It is possible from its slightly worn condition that it is the fourth premolar, but the form is that of a true molar. The surface of the crown is marked by shallow grooves not very closely placed. The three premolar teeth in advance of this tooth are broken oif. Their bases are narrow. There are no basal cingula on the molars. 428 THE WASATCH EPOCH. Measurements. u. Leugth of posterior true molars 033 Diameters of M.iii^»"t"°l"'«'«"'"" "|^ ( transverse "'" Diauu-tersofM.Til ""'""?•'«'«"'"■ ] °!^ ( trausverse "ii Depth of ramus at M. ii "30 Tlie characters of the teeth of this species are something hke that of some of the Paloeochceri of the Miocene, and resemble more those seen in some of the bears. From the Big Horn River; J. L. Wortman. PHENACODUS Cope. Paleontological Bulletin, No. 17, p. 3, 1873. Report on Vertebrate Fossils of New Mexico, U. S. Geog. Sur\s. W. of lOeth meridian, 1874, p. 10. Ibidem, p. l*i. Report U. S. Geol. Survs. W. of lOOtU meridian, IV, Part II, p. 173. American Naturalist, 1881, p. 1017. Paleontological Bulletin, No. 34, p. 177, 1881. The characters of this genus are derived from the typical species, the P. primoevus, and from the P. vortmani, both of which are represented by almost perfect specimens. The skull is distinguished by the anterior abbreviation of the nasal bones, and the consequent partly superior aspect of the anterior nostrils. Posteriorly these bones are can-ied farther than usual, extending between the orbits; in P. primoevus constituting a slightly nearer approach to the living genus Tapirus than is usual in other Eocene genera now known. The premaxillaries are slender, and do not unite in front. Posteriorly they reach to the nasals, but not to the frontals. Theie are no postorliital pro- cesses either of the frontal or malar bones. Sagittal crest present. The palate is excavated beyond tiie posterior l)order of the last superior molar, and the pyramidal processes of the palatine bone are not separated from the maxillaries by a notch. Postglenoid processes prominent, no trace of preglenoid ridge. Posttympanic process short, widely separated from the postglenoid in front by the meatus auditorius, and from the paroccipital behind by the robust bases of both processes. Petrous bones lost, but probably small. Frontal bone deeply and widely excavated anteriorly to receive the nasal bones. Parietals extending forwards lo their usual position poste- rior to the orbits. Tho mastoid l)on(> well exposed botwocn the occii)ital CONDYLARTHRA. 429 and squamosal. Alisphenoid joining the parietal. Lachrymal bone larger, extending anteriorly and posteriorly to the anterior border of the orbit. Incisive and infraorbital foramina present. Lachrymal foramen not exterior to the orbit. An alisphenoid canal, into which the foramen rotundum opens. Foramen ovale separated from the foramen laceriim anterius. A' postglenoid foramen. Carotid foramen grooving the side of the basioccip- ital bone forwards and upwards. The condition of the foramina lacera uncertain, owing to the loss of the petrous bones Foramen condyloideum distinct. Postparietal and supraglenoid foramina present. The mandibular rami are not coossified at the symphysis. The con- dyle is elevated, standing a considerable distance above the line of the molar teeth, and its articular surface looks mostly upwards. On the inner half it is decurved so that the posterior half looks posteriorly. The coro- noid process is elevated, and the angular region is in the same vertical plane. The dental formula is: I. -; C. -; P-m. -: M. . The incisors have 3 1 4 3 transversely expanded sharp-edged ci"Owns. The canines are not very large. The anterior pi-emolars are a little spaced, but there are no distinct diaste- mata, except in P. primcevus, a short one behind the first inferior premolar. The first premolar in botli jaws is one-rooted and has a simple crown. The third and fourth superior premolars have internal lobes and two external • cusps. The true molars have two internal, two intermediate, and two ex- ternal tubercles. The external faces of the latter are convex. Anterior cingular cusp rudimental. The third and fourth inferior premolars have an internal median cusp, and the fourth is not like the first true molar. The true molars support four cusps opposite in pairs, and an odd one between and behind the posterior two. This tubercle is developed into a heel on the last molar. The numbers of the vertebrae are C, 7 ; D, 14-15; L, H or 7 ; S, 3 or 5. The numbers are certainly known in P. vortmani, and also in P. primcevus, excepting in the case of the dorsals. Of tliese there- are thirteen preserved in the specimen of P. primcevus; one is probably lost from the front of the series, and one, probably the thirteenth, from the posterior part 430 THE EOCENE PEEIOD. of the column. The number of the caudal vertebrae is not known, but they were numerous. The transverse process of the axis is shoil and flat, and not narrow as in lapirus, and its base is perforated posteriorly by the vertebrarterial canal. The latter issues on its inferior face, and perforates the neural arch transversely just above the superior border of the cotylus for the occipital condyle. The axis has a cylindric odontoid, and atlantal facets well sep- arated. Its neural spine is well developed. A vertebrarterial canal. The articular faces of the succeeding cervicals are oblique and slightly opisthoc- oelous. The transverse processes are narrow, are directed posteriorly, and have no descending processes except on the sixth centrum. Seventh cervi- cal without vertebrarterial canal. The second dorsal has rather elonerate diapophyses without metapophyses ; the neural spine is nan-ow and rather elevated. The metapophyses are quite elevated on the posterior part of the series, and the centra become somewhat opisthocoelous and depressed. No anopaphyses on either dorsals or lumbars. The latter have well-developed flat diapophyses, and the centra are keeled below. The postgygapophyses are not revolute, but they become oblique, so that the external parts of the surfaces are nearly vertical. The centra of the sacrum are rather elongate, and are of equal length. The diapophyses of the first sacral are short and deep, and present no articular facets for the diapophyses of the last lumbar. The iliac articular surface extends over the first and part of the length of the second sacral vertebrae. The rest of the sacrum has united diapoph- yses continuous with it. The caudal vertebrae were probably numerous, the proximal have strongtransverse processes, and the median are robust in the P. primcevus. Some of them have chevron bones. In the ribs the capitular and tubercular facets are well developed. The shafts are flattened excepting at the posterior part of the series. The epis- ternum is elongated and compressed, and it has two costal articular facets near its middle. The anterior sternal segments are narrow; the posterior are wider and flattened. No clavicle. The scapula is widened anteri- orly as in the ursine Carnivora, the Amblypoda, and the I'roboscidea, and has a short coracoid process. The spine rises abruptly from the neck, and turns forward in a strong acromion. '^I'lie tuberosities of the humerus are CONDYLAETHRA. ' 431 well developed as in tapiroids. The condyle has no intertrochlear ridge, but the cylindrical part is swollen, as in Oreodon, Anoplotheriwn, and Mesonyx. The epitrochlear foramen is a peculiar feature already mentioned. The head of the i-adius is transversely oval, without inferior interlocking angle. The distal extremity is truncate, and the scaphoid and lunar facets are not dis- tinctly separated. The distal extremity of the ulna is a compressed tuber- osity which is produced beyond the radius, ta which it is oblique. The scaphoid is rather larger than the lunar, and has a considerable pos- terior tuberosity. Its radial facet is transverse and anterior, and the median part of the bone is concave. The inferior face is one large facet for the trape- zoides. The facet for the trapezium is small and lateral. The facet for the magnum is small and is entirely lateral. The radial face of the lunar is larger, and the rest of the superior side of the bone slopes downwards and is less concave. The inferior face is occupied in front almost exclusively by the facet for the magnum. A narrow facet for the unciform forms a narrow band along the external part of the inferior face. The cuneiform has considerable transverse extent. Much of its superior face is occupied by a concave facet for the ulna; the external part is contracted, and termi- nates acutely. The inferior face is nearly flat. The trapezoides is a shallow disciform bone, entirely supporting the scaphoid, and not joining the lunar. The magnum has a resemblance to that of Goryphodon. It has an anterior face, a posterior tuberosity, .and an elevated smaller superior tuberosity. It is narrow, and the inferior facet is simple and concave. The unciform is a good deal like that of Tapirus, but has a small posterior tuberosity. Viewed from before it is subtriangular, the cuneiform face being the hypoth- enuse. There is no distinct facet for the lunar articulation, as is seen in CoryphodoH and Bhinocerus. It has two inferior facets. The trapezium is lost from the specimens of both species. The distal keels of the metapodial bones are distinct, but are quite short, and entirely posterior. The pelvis is of normal proportions. The ilium is not much expanded, but its posterior superior border is thinned out. The anterior border is de- curved in front. The peduncle is distinct and rather short, and has a trian- gular section, the narrower face being anterior and only apparent near the 432 TUE EUCEXE PERIOD. acetabulum. A trace of aa anterior inner spine. Posterior edge at aceta- bulum not expanded. Scissura acetabuli open. The ischia are shorter than the ilia, and the shaft is flat, and the tuber not enlarged. There is an an- gular spine. The base of the pubis is compressed. The head and great trochanter of the femur are distinct, and the latter is as elevated as the former. It is excavated by a deep trochanteric fossa. The little and third trochanters are prominent, the latter near the middle of the shaft. The condyles are well separated. The rotular groove is not short or wide, is well excavated, and the internal ridge is the most produced. The tibia is not elongate, and has a large head. The crest is truncate obliquely above. The distal extremity is small and robust, and the malleo- lus is prominent. The astragalar grooves are not oblique. The fibula is distinct throughout, and is rather stout. Its extremities are not much ex- panded. The posterior foot was not plantigrade, but proportioned much as in Tapirus, adding a digit on each side to the three possessed by that genus. These digits are arranged in the arc of a circle, so as not to give unusual width to the foot. The third is longer than the second and fourth, and the fifth is longer than the first. The astragalus has much the form of that of a carnivorous mammal. The lateral crests are well developed, and of une- qual elevation, the external being the most elongated. The median groove is wide and deep. The neck is distinct, and is rather long, and is bent slightly inwards. The head is transversely oval, and its articular surface is uniformly convex in all directions. The caleaneum is of average length, and has a compressed shaft. It has no horizontal extension at the astraga- lar condyle, and the sustentaculum is robust and short. The cuboid facet is oblique towards the astr.agalus, with which it is about equally produced. The navicular is a sim])le, short, saucer-shaped bone, much like that of the carnivora. The ectocuneiform is robust, and has a prominent jiosterior tuberosity. The mesocuneiform is shorter, and is transverse. The ento- cuneiform is longer and narrower than the others. The cuboid is a robust bone, with a large posterior tuberosity Its proximal extremity has l)utone articular face, which is convex anteropostoriorly. The phalanges are not shortened, and the ungues are well developed, flat, and obtusely angular. COXDYLAETHRA. 433 A cast of the cranial cavity gives the following as the general charac- ters of the brain. The cerebral hemispheres are remarkably small, each one being less by one quarter than the cerebellum. They are sejDarated from the latter and from the large olfactory lobes by strong constrictions. The posterior one is occupied by a thick tentorium. In like manner a wide groove for a robust falx separates the hemispheres above. A notch repre- sents the Sylvian fissure, and the lobus hippocampi is quite large. The vermis of the cerebellum is quite distinct, and the lateral lobes are large. They are impressed laterally by the petrous bones, as in various ruminants. The anterior columns of the medulla are not visible. There are traces of the convolutions on the hemispheres. I refer nine species to this genus. Of these only two, P. primcefvus and P. vortmani, are sufficiently well known to render the generic reference certain. The others are mostly known from teeth, and it is highly probable that most of them belong to the genus. They are all from either the Puerco or Wasatch formations — three from the former and six from the latter. Species which are known from mandibular teeth may be distinguished as follows : Large ; true molars .041 ; Pm. iv .014 ; depth of ramus at M. ii, .027 P. jyHmceviis. Medium ; true molars .027 ; depth at M. ii, .017 ; last molar smaller . . . . P. vortmani. Like the last, but the superior true molars without median external marginal tubercle. P. puercensis. Length of true molars .0258 ; some of the ijremolars with flat expanded heels. P. calceolatws. Smaller ; true molars .022 ; depth at M. ii, .013 ; last molar elongate .P. macropternus. Smaller ; last four molars .027 ; Pm. iv, .007 ; depth at M. ii, .013 ; last molar with short heel P. hracliyptemus. Smallest; true molars .017; depth atM. ii, .012 ; heel long; cusps elevated. P. ^wMieMSis. Besides these, the P. nunienus is founded on some bones without teeth, and the P. heniicomts on superior molar teeth only. The P. sulcatus of the Report of Capt. G. M. Wheeler, Vol. IV (1877), probably belongs to some other genus. 28 C 434 THE WASATCH ErOCH. Phenacodus nuniencs Cope. Plate LVIIh; figs. 1--2. The largest species is represented by humeri and parts of a scapulae of two individuals, and probably by other bones, which were found mingled together with the bones of a P. primcevus and a Mesomjx ossifragus in great confusion. Tiiese bones can be compared with those of P. primcevus, and several differences besides the superior dimensions appear. The glenoid cavity of the scapula is longer anteroposteriorly and nar- rower transversely than in P. primcevus. The proximal part of the spine rises nearly half way between the anterior and posterior borders of the neck ; in P. primcevus it is much nearer the posterior edge of the neck. The head of the humerus is more nearly rounded and less extended obliquely forwards and outwards than in P. primcevus. The tuberosities are less prominent, and the greater has a more obtuse extremity in the P. nunienus. The subscapularis facet on the inner side of the lesser tuberosity is more distinctly defined, forming a well-marked groove running upwards and for- wards. The deltoid crest extends down the shaft, and is represented b}- an angle as far as the fossa for the head of the radius. Tlie epicondyles are not prominent ; the inner is the most so, and is marked by the arterial fora- men. The bridge inclosing this is quite narrow. The condyles have a thin- edged flange on each side posteriorly. Anteriorly the external disappears, and the internal becomes beveled so as not to be acute. Measurements. M. Total length of humcrua '245 Width at proximal extremity 066 Anteroposterior diameter of head 044 Widtli of humerus distally 065 Width of condyles in front 040 Width of condyles posteriorly O'Z! Median diameter of condyles O'ii Diameters proximal end scapula 5 anteroposterior 05i ( transverse o:tl Length of glenoid cavity 040 Width of neck 049 Several posterior feet accompany the bones, some of which are clearly those of P. prim- longitudinal 028 , . . < vertical "SS I 'transverse 025 Diameters of second lumbar \ posterior transverse 030 *- longitudinal 034 Transverse extent of postzygapophyses 0-6 Anteroposterior width of diapophyses at hase 023 ( . ■ < vertical 021 \ anterior < f,«Q Diameters centrum of first sacral <^ ( transverse ">'<' ( anteroposterior 030 Expanse of diapophyses of first sacral 068 ( , . < vertical 019 \ posterior ( non Diameters fourth sacral < (transverse " — ' anteroposterior 035 c . ■ < vertical 021 V posterior^ f,,, Diameters first caudaU < transverse "^i ( anteroposterior ^^■^ Length of caudal with one strong diapophysis 029 Length of diapophysis of do 014 Length of caudal with two short diapophyses, the posterior longer 034 Length of diapophysis, do 007 I anteroposterior 037 Diameters caudal with two equal diapophyses^ anterior vertical 028 ( anterior transverse 019 Length of d iapophysis 005 Length centrum without neural arch 038 Length distal centrum 030 Posterior diameters of do. < ' f... ( transverse oi* The neck of the scapula is not much contracted, but the anterior border is turned abruptly forwards, before assuming its anterior convexity. The apex is rounded, and not acuminate, as in the amblypodous genera known; on the contrary, the distal posterior curve is strongly convex. From this point to the neck, the posterior edge is nearly straight. The spine is elon- gated. The proximal part of its edge is broken, but at the middle it widens to a narrow roughened surface, and thence gradually descends, and disap- pears three centimeters from the edge. The glenoid is a wide oval with an anterior acumination on a short acuminate tuberosity. The coracoid is an abruptly recurved hook with obtuse apex vertically compressed, looking inwards. Its base is separated from the edges of the glenoid cavity by a groove. The inferior face of the scapula is without noteworthy ridges or grooves. I find no indication of clavicle. The outline of the scapula is #' 448 THE WASATCH FAUNA. unlike that of any Perissodactyle, but the head is more like that of Hi/ra- cofherium veuticolum than any other member of that order accessible to me. The coracoid is less incurved in ILjrachyus agrestis, and is entirely flat in Tapirus terrestris. Measurements of scapula. j^ Length measured along spine 179 Width, .030'" from proximal end of spine 077 Semi-diameters of glenoid cavltvj''"t'^^''P°^"""'"" 036 ( transverse 0i9 AVidth of neck 036 Length of coracoid from internal base 008 The sternum is represented by six segments witli a possible seventh concealed by the fore-arm which lies across it. Its characters are unlike those of the Perissodactyla, and resemble rather those of some of the Coni- vora. It has some resemblance also to that of Hyrax. The presternum is much compressed, and two-fifths of its length projects in front of the facets for the first rib, as a compressed prow. The compression is less marked at the posterior extremity. The second segment is in section a vertical paral- lelogram. The fourth segment is an oblong flattened plate, and tlie fifth is a nearly square flattened plate with the angles truncated. The sixth is wider than long, with the posterior angles much more broadly truncate than the anterior, and the posterior border excavated. The seventh is much narrower than the sixth, and is flat below. Its distal extremity is lost. It is probably the xiphisternum, so that the number of segments is the same as in Hyrax and the Ituminantia, and one more than Tapirus and the hogs. It dift'ers from that of Hyrax in the ossification of the presternum, and the greater width of the mesosternal segments. The latter are therefore of a totally dift'erent form from the corresponding segments in Perissodactyla, in- cluding Jlyrachyus, but similar segments are seen in Coryphodoii. Measurements of sternum. Length of presternum 085 Width at rib-facet 026 Unteriorl^-'"^''^"' 018 Diameters second segments (transverse 016 ( anteroposterior O.l'j Length fourth segment 0-.J9 Width fourth segment behind 031 r.. . ^ri .< transverse (least) 03"2 Diametera fiflli »i-giiient ' ^ ' ( anteroposterior 026 ,,. . ■ ., .,< transverse (least) 026 Diameters sucth segment : ^ ' ( anteroposterior 020 Width of second segment medially 014 CONDYLAETHRA. 449 The humerus is rather robust. Its muscular ridges are well developed. The deltoid extends two-thirds the length, and the external epicondylar ridge rises as it disappears, and is most prominent near its origin. The head is an anteroposterior oval supplemented by the very large greater tuberosity, and the small but prominent lesser one. The edge of the former is raised, and near its posterior end overhangs a distinct large round facet for the teres minor tendon. The ridge for the insertion of the teres major rises to the inferior overhanging edge of the head a little posterior to this facet. The subscapularis facet of the lesser tuberosity is large and transversely lenticu- lar in shape. It is bounded below by a strong angular ridge. There is a low ridge in the fundus of the wide bicipital groove. The inner side of the shaft for some distance above the condyle is flat. An inch above the condyle its section is triangular. The epicondyles are not prominent ; the internal is a small tuberosity, which is continued into the narrow and short bridge that incloses the epitrochlear foramen. The condyles have greater transverse extent than in most Diplarthra, resembling rather that of Proboscideans and Carnivora. The internal flange is prominent, and the external cylinder is quite convex in longitudinal direction, as in Oredon, but less prominently. The Phenacodus primavus displays its primitive and Proboscidian char- acter in the relations of the bones of the cubitus. Instead of having the ulna more slender than the radius, as in Hycracotherium and the modern Peris- sodactyla, or equal to it in diameter, as in Hyrachyus, the shaft of the ulna is more robust than that of the radius. The olecranum is not acuminate, but is obliquely truncate, and is flattened below. The middle of the shaft is compressed ; its internal side is nearly flat, or a little concave, while a ridge marks the middle of the external side. This ridge becomes an angle on the distal third of the bone, and almost disappears. Above this ridge there is a wide, rather shallow, groove, which is bounded above by the angular external edge of a narrow superior truncation on which the radius rests. At the distal extremity the external face has a shallow median groove. On the inner side the tuberosity which is applied to the radius is three centi- meters from the extremity. The carpal facet on the latter is a narrow oval, convex in both directions. 29 o 450 THE WASATCH FAUNA. The section of the middle of the shaft of the radius is an oval placed obliquel}" with the superior extremity truncate. This truncation narrows and becomes the narrow convex internal edge proximally. Distally it ex- pands into the inner face of the superior arched surface. The head is a transverse parallelogrammic oval, with the internal extremity flared for- wards at an angle of 45°, and narrowed. The middle line of the distal two- fifths, below, is a prominent angular ridge, which disappears proximad to the extremity. The latter is enlarged, and contracts to the carpal facets, espe- cially from above and below. The lunar facet is wider antoroposteriorly than the scaphoid, and has an indication of distinction from it. The cuneiform surface of the ulna is placed at an open angle to them, and is narrower than either. The shaft of the radius is curved, and the superior outline is convex. Meajiurements of anterior limb. II. Length of bumeniB 173 ( anteroposterior (greatest) 061 Diameter of proximal end j ^^.j^pg^.^^gy < at bicipital groove 032 ^ < at lesser tuberosity 042 Anteroposterior diameter of shaft at middle 027 Width at epicondyles 044 Width of condyle 035 Anteroposterior diameter condyle ) "^t**""* ^7 "" ' •' i internally 030 Length of nlna 204 Df pth at extremity of olecranon 026 Depth at coronoid jirocess 03S Depth at middle of shaft 021 Diameters of distal tuberosity \ vertical 015 ( transverse 022 T.. . , , <. .< vertical 009 Diameter of carpal facet I t transverse OIU Length of radius 14.t Diameters of head of radius J ^*'^*"''' "^^ c transverse 030 Diameters at middle shaft | ''"^''"'' "^"^ ( transverse Olo i^. . r 1- . 1 1 . ^ vertical 02.'> Diameters of distal enlargements ( transverse 030 Tu „ , r 1 r 4 < vertical (lunar) 013 Diameters of carpal facets ^ ' ( transverse 024 The carpus is entirely preserved in my specimen. The general fea- tures have already been described under the head of the genus Phenacodus. The radial surface of the scaphoid and lunar is very convex in the antero- posterior section, descending well on the ;nitcrior face, and leaving the ante- CONDYLAETHKA. 451 rior external face wider than deep at the middle. The external face of the cuneiform is four times as wide as deep. The posterior tuberosity of the scaphoid is acuminate; that of the lunar is shortly truncate, and that of the cuneiform vertically compressed and narrowly rounded. The concave ulnar facet of the last bone covers three-fifths the length. There is but one infe- rior facet of the scaphoid, which is a little wider than deep, and has a me- dian angle directed posteriorly. On the external side posteriorly there is a vertical oval facet for the magnum. The inferior face of the lunar has three facets; one anterior for the magnum; one internal, which widens posteriorly, for the magnum ; and one external, narrow claviform, narrowing posteriorly, for the unciform. The unciform face of the cuneiform is two-thirds its trans- verse, and all of its anteroposterior width. The trapezium is a flat bone, with slight contact with the scaphoid, and extending distal to the trapezoides. It is wide anteroposteriorly and lias a narrow distal facet. The trapezoides have a wider anterior face than the magnum. Its shape is discoid, and its ante- roposterior diameter exceeds the transverse but little. There is no posterior tuberosity. The trapezial facet is accompanied by a notch of the external superior edge. The inferior edge of the anterior face is convex. The mag- num is the smallest bone of the carpus (except perhaps the trapezium). It is compressed, and has the usual elevated median superior tuberosity. The anterior face is subquadrate. There is but one inferior facet, which is con- cave anteroposteriorly. This is bounded on the inner side of the bone by a vertical facet half as wide as the inferior, for the extei'nal proximal edge of the second metacarpal. The facet for the unciform on the external side extends from the entire anterior face upwards and backwards to the supe- rior tuberosity. The posterior tuberosity extends very little posterior to the inferior facet. The external or anterior face of the unciform is a right- angled triangle with the perpendicular side inwards, and equal to the hori- zontal, which is a little convex downwards. The internal side has two facets, one superior oblique for the magnum, the other anterior and trian- gular for the edge of the third metacarpal. The inferior facets are concave anteroposteriorly, and that for the fifth metacarpal is two-thirds the width of that for the fourth. 452 THE WASATCH FAUNA. Measurements of carpus. u. Transvei-Be diameter of proximal row 046 J anteroposterior 023 longitudinal 013 transverse in front 013 c anteroposterior Old Diameters laDar< longitudinal 015 ( transverse in front 014 / anteroposterior at middle 012 Diameters cuneiform < longitudinal 010 ( transverse 027 Urosimal|'""*™P°''^*'""'^ "1* Diameters of trapezoides< « transverse 013 ( longitudinal 003 fyertical^'-'f^""* 010 Diameters maBnum J < at middle 015 I anteroposterior OiO (.transverse in front Oil S vertical (inner side) 015 transverse 017 anteroposterior 016 The metacarpal bones are all preserved, including that of the pollex. The latter is however broken, leaving a slight uncertainty as to its exact length. The proximal facets of these bones differ from those of the metatarsals in their being more curved anteroposteriorly, or less flat. They are a little shorter and less robust than the corresponding metatarsals. The external or fifth is the same size as the fifth metatarsal, but is differently formed prox- imally. The second and third metacarpals have external lateral bevels or facets for the next carpal. Tlie second metatarsal is the only one of its series that has such a facet. The proportions of the three principal meta- carpals are veiy similar to those of the corresponding metatarsals. That is, the second and fourth have the same distal production, reaching the liga- mentous fossa of the median metacarpal, but the second is a little the longer owing to its more proximal origin. In all three each proximal extremity extends a little over that of the one adjoining it on the external side, the external face being concave below the lateral facet. The condyle of each is flat anteriorly, arul the groove that cuts it off from the anterior face of the shaft is very shallow. The distal surface is very little convex. The keel is quite short, and rather prominent. Both anterior and posterior faces of the shaft are flat. The form of the distal articulations of the metacar- pals is that of an ungulate rather than that of a clawed mammal. Those of CONDYLARTHKA. 453 Mesonyx, which a good deal resemble them, have the unguiculate character, although not very pronounced. Tlie fifth metacarpal is just half the length of the third. In its proportions it reverses those of the corresponding meta- tarsal, for the proximal extremity is only one-half the width of the distal. In the metatarsal the proximal is the wider extremity. The proximal facet of the metacarpal is sublenticular, and descends anteriorly, the anterior apex being at the inner side. Opposite the latter, on the external side of the shaft, is a low tuberosity. The distal extremity is a little oblique, but the posterior extremity of the heel is nearly median (though it commences at the inner side), and the lateral distal faces are in the same plane. The internal side of the proximal extremity of the second metacarpal is rough- ened with two longitudinal fossae, bounded by bands of the surface, of which the anterior is flattened. Measurements of metacarpus. M. flongitndiual 065 mediau transverse 014 Diameters of second ■( I distal ^ anteroposterior 014 t I transverse 015 'longitudinal 072 proximal ^ ''°*'"°P°"f*'"°' ^" Diameters of third dist.tl diameters < ^,,. '^ ( transverse Olio Third digit P<'°«'^'v;.-;v" Z " ( width of distal facet 012 ( length above 013 Fourth digit{ i vertical 0075 ^distal rtiameters^ ,^,,„^,.^.^^^ 0115 1 1 1 . — Of vngual phalanges. 014 Firstdigit-J ( of neck 00C5 greatest 008 (length 019 Second digits - nt neck 010 < ^idtl" I greatest 014 (length.. . rirst digit-' , of / width X „ CONDYLAETHRA. 455 H. I length 019 Third digit^ , at neok 014 ('''^^^ I greatest 016 (length 018 Fourth digit^ , at neck 0115 < ^'"^^^ 1 greatest 013 C length 013 Fifth digit.? , at neck .007 < ^"Itl^ ^greatest 008 The ilia are flat, and not very wide. The superior edge expands rather abruptly at the neck, and then follows a curve nearly parallel with that of the anterior border. The external face of the expansion is concave. The anterior apex of the crest is subacute and decurved. It is robust and subtriangular in section at base. Just above the position of an anterior inferior spine, and near the edge of the acetabulum, is a deeply impressed subtriangular fossa. The obturator foramen is very large. The anterior edge of the ilium is much thickened and for most of its length is one-third the transverse diameter of the plate The plate is abruptly thinner above this line. The internal face of the innominatum is concave behind the acetabulum, and the posterior edge is thickened and reverted at this point. The inner face of the ischium is flat; the plane of its distal portion is nearly at right angles to that of the plate of the ilium. The position of the tuber ischii is but little thickened, and is very little curved outwards. It is less prominent distally than the inner part of the posterior border. The entire ischium is rather thin. The external face of its shaft is convex near the obturator foramen. Measurements of pelvis. m. Total length through acetahulum 280 Length of ilium to acetabulum 140 Width of plate of ilium at middle 060 t interiorly 0'27 Width of peduncle ) anteroexteriorly 019 ( posteroexteriorly 026 rx. , 1,. 4.1 ( anteroposteriorly 026 Diameter pubis at base < '- •' ( anterointernally 009 Length of obturator foramen 070 Width ischium at spine 036 Width of ischium at middle of obturator foramen 026 Width ischim from tuber to symphysis 069 Diameters acetabulum ^'^'"'"'^^^■■--; ^^^ ( anteroposterior 038 The femur is a rather stout bone, rather more robust than that of the Tapirus ierrestris. That is, it is shorter, but of equal diameter, and with 456 THE WASATCH FAUNA. condyles nearly equal in proportions. The head has a peculiar shape, which is also found in the Phenacodus vortmani; it is oval instead of round; the long diameter crossing that of the trochanters at a very wide angle out- wards and backwards. The posterior face is most flattened, and here the fossa ligamenti teris forms a wide notch in the edge. The great trochanter is large, and projects as far as the head, from which it is separated by a deep notch. Its superior edge is transverse, terminating in an anteriorly directed apex, and inclosing with the prominent posterior edge a deep trochanteric fossa. Summit of great trochanter beveled obliquely out- wards. The little trochanter is prominent. It commences opposite the lower fundus of the trochanteric fossa, and terminates opposite the superior edge of the third trochanter. The latter is above the middle of the lenyth of the femur, that point marking the inferior edge of its truncate extremity. It is well-developed, and its truncate edge has a lenticular outline. The borders of the latter are prominent, so that the anterior and posterior sides are moderately concave. The internal side of the shaft is rather broadly rounded. The external edge is angular. The rotular crests are prominent and thick, and the interior is the more prominent and prolonged upwards. It is not, however, swollen as in some recent Perissodactyles. At the pos- terior base of the external condyle is a sliallow fossa. A much wider and deeper one lies above the inner condyle and the inner half of the inter- condylar fossa. The latter is wide, equaling the internal condyle in width posteriorly, and is a little narrower than the external condyle. The greater width of the latter is caused by the prominence of its external border, which encloses with it a groove, which is very shallow except at its superior termination at the superior quarter of the face. Just above and external to this part of the groove is a smaller fossa. Other than this and a shallow fossa of the internal side, the lateral or epicondylar fossae are not marked, nor are there any between the condyle and the rotular ridge, as in Hyra- cotherium ventkolum. The patella is a short, wide, thick bone, terminating in a rounded angle below. Above it is truncate, with a transverse groove at the middle. CONDYLAETHRA. 457 Measurements of femur, M. Total length from head SS-^ Length to line of middle of third trochanter 097 Length to internal rotular crest 185 Diameters of head J ^°°S 035 ( short, at middle 028 Total width proximally 071 Total width at third trochanter 047 Total width below third trochanter 031 Width of rotular groove, with crests 025 Greatest width of condyles 058 Depth of condyle at inner rotular crest 068 I longitudinal 032 Diameters of patella < transverse .028 ' anteroposterior above 019 The tibia is about as long as the femur, and, like it, is a rather robust bone. The crest is thick and not prominent, and at its proximal part is broadly truncate. The halves of the spine are well separated from each other. The external cotylus is a wide anteroposterior oval, slightly con- cave. The interior femoral face is of somewhat similar form, but is much decurved posteriorly, so as to be convex anteroposteriorly. The popliteal notch is wide and regularly concave. The external lateral fossa is well marked only proximally; the posterior edge of this side is obtuse. The posterior edge of the external side is more acute above, but disappears be- low. The section of the shaft is triangular, but the obtuse anterior angle becomes the anterior edge of the malleolus. The latter bounds most of the internal astragalar groove, sinking posteriorly. The tibia projects behind the groove mentioned, so that the posterior face is not flat in the transverse direction like the anterior face. The transverse diameter of the astragalar articulation coincides with that of the head of the tibia, and the astragalar grooves are at right angles to it. • The fibula is moderately slender, with rather large exti-emities. The proximal surface is an anteroposterior oval, concave to fit a posterior con- vexity of the tibial facet. The distal extremity is truncate, and has a nearly vertical internal face. Its anterior face is about as wide as its exterior, and the angle they form has a low tuberosity. No tendinous grooves. 458 THE WASATCH FAUNA. Measurements of tibia and fibula, 11. Total length of tibia 210 { anteroposterior at internal cotylus 048 Diameters of head^ anteroposterior at popliteal notch 034 ' transverse 1.. .055 Anteroposterior width of shaft at distal third 020 Diameter distal end tibia ^'"'**™P''^'«""'(S'"«'^**«*) "33 ( transverse 032 Length fibula 186 Proximal diameter ^'^'^^^'■"P"**''"'"" 02"^ ( transverse Oil Diameter of shaft Oil Distal diameter 5 ''°*«'"''P««*''"*"" 025 i transverse 019 As compared with the tibiae of Hyracotherium venticolum and Hyrachyus agrestis, that of the Phenacodus primcevus displays its simplicity in the absence of the notch of the anterior external border of the head and of the tuberosity which, especiall}' in the H. agrestis, bounds it in front. The distal extremity agrees with that of the Hyracotherium in being in the same plane as the head, but it diifers from both the species in the large flat malleolus. In the Perissodactyla named, it has a small anteroposterior extent, and its extremity is widely beveled in a fashion not seen in the Phenacodus. The posterior foot is one-half longer than the anterior foot. The cal- caneum and astragalus are about the size of those of Hyrachyus agrestis, but the median toes are a little shorter. The trochlea of the astragalus is about the size of that of the last-named species, but the groove is not so deep nor so wide. The head is nearly as Avide as the trochlea, and its face is in front of the inner two-thirds of- the latter, and extends in front of the malleolus of the tibia. Its anterior and external outlines viewed from above form a regular curve, a segment of a wide ellipse, to the line of the front of the trochlea, where the outline contracts abruptly. The navicular articular face is wider than deep, and is turned somewhat under. Superior face of head flat. There is no deeply-impressed fossa on either side of the trochlea of the astragalus as in Hyrachyus, etc. The calcaneum has much the shape of that of Hyrachyus agrestis, but is more robust. The sustentaculum is much more massive, having the vertical sides and a flat inferior face of equal width. The cuboid facet is transversely diamond-shaped, nearly as deep as wide, and without notch near the astragalus. There is a quite CONDYLARTHEA. 459 prominent external ridge which descends forwards from the base of the astragalar condyle to the external angle of the cuboid facet, which is want- ing in the Hyrachyus. The posterior extremity is truncate, excepting a tuberosity of the inner edge, which is acuminate. The navicular is wider than deep, and has a notch in its posterior bor- der. There is a short tuberosity' on the postero-external corner. The ex- terno-posterior angle is somewhat produced, but it does not extend to the posterior side as in H. agrestis. The cuboid is a robust bone longer than wide. Its proximal face is wider than deep, is straight and oblique down- wards and outwards transversely, and modei'ately convex anteroposteriorly. The tuberosity looks downwards, and extends across the entire posterior face, including a deep transverse groove. The ectocuneiform is much the largest of the cuneiforms ; its is twice as long as the mesocuneiform, and a little wider. Its outline in front would be square but that a concavity exists on the distal half of the external face. The anterior face of the mesocunei- form is a transverse parallelogram. The entocuneiform is a flat bone, as long as the ectocuneiform, and with a narrow anteroposterior articulation with the navicular. Its external face is straight longitudinally and convex anteroposteriorly. It is a little wider anteroposteriorly below than above. Its inner face is half in contact with the mesocuneiform and half with the second metatarsal The proportions of the metatarsals are a good deal like those of the metacarpals. The length of the first is two-fifths that of the third, and that of the fifth is one-half that of the third. The second has a lateral facet for the ectocuneiform; the others have a single proximal facet. The second and fourth reach to the distal ligamentous fossse of the third. The middle three are i-ather robust, especially distally. The distal condyles are seg- ments of plane transvei-se cylinders, interrupted postei-iorly by the short obtuse keel. A shallow transverse groove bounds the condyles proximad in front, being better marked than in the anterior foot. The proximal ex- tremity of the first metatarsal is compressed, and the distal extremity is compressed and oblique. The proximal extremity of the fifth has two faces, the internal, naturally, for the fourth. The external is a tuberosity which nearly touches the posterior tuberosity of the cuboid. 460 THE WASATCH FATJifA. The phalanges are absolutely longei* and narrower than those of Hy- rachyus agrestis; those of the second and fourth digits are also flatter. The iirst phalange of the hallux is subround proximally, and its form is some- what irregular. The superior face is concave ; there is a low tuberosity on the external side below the middle, and the side next the second is flat dis- tally ; the distal facet is deeper than wide, and is not recurved above. The proximal facets of the second and fourth phalanges are less transverse than that of the median phalange ; i. e., they are narrower and more convex above. Their distal facets are not emarginate, and are but little recurved. The second phalanges are nearly square, or as wide as long. The proximal superior edge is a little produced ; the distal facets are not emarginate, and are very little recurved. The ungual phalanges are even more obtuse than those of the anterior foot, especially those of the first, third, and fifth digits. As in the case of the other phalanges, the median is the most depressed, and they become less depressed to the first and fifth. The ungues of the sec- ond and fourth digits are rather more acuminate than those of the first and tifth ; while that of the fourth is broadly rounded. They all have a median foramen just within the border. The neck is but little constricted, and the proximal angles are not produced. The inferior sides of the ungual pha- langes have a flat proximal area rather larger than a semicircle, between which and the margin is a concave space of a very wide crescentic form. Measurements of posterior foot. M. Total length from heel 162 Length of tarsus 106 Length of median metatarsus 073 Length of median digit 066 I. — Tarsus. Xength of calcaneum 082 Depth at heel 022 Width at sustentaculum 035 Depth at astragalar condyle 031 Diameters cuboid facet ^ vertical 021 < transverse 024 Length of astragalus on inner crest 042 Length of astragalus on outer crest 033 Width of trochlea, including crests 025 External elevation of trochlea 022 Diameters navicular face ^ ^'"^'"^*^ °^^ transverse 024 '\ Diameters naviculars Diameters cuboid < PHENACODUS. 461 M, longitudinal Oil proximal I »°'®'^'>P°«t«''''»' °"^ < transverse 026 proximal J '^°*®'"°P°«*«"°'^ ^^'^ I transverse 018 longitudinal median 024 median^ '^°*«"'°P''^*«^<"^ ^^^ (. I transverse 025 ■ anteroposterior 030 Diameters eotocuneiform< vertical 016 ( transverse 016 Anterior diameters mesocune'iform \ < transverse Oil (proximal I ''"teroposterior Oil Diameters ectocuneiform < ( transverse 006 ( longitudinal 016 II. — Metatarsus. Length first 028 Anteroposterior diameter < P ,, ^ < distally 012 Length of second 068 Proximal diameters 5 ••^''*''^°P°«*^"'"' «1^ '. transverse 015 Distal diameters 1^°*'^^°P°«*«"°'' ^^* ( transverse 018 Width of head of third 018 Greatest width above condyle .-r 021 Width at middle of shaft 014 Distal diameters J •''"*'^'-°P°^'''"°'^ ^^^ ( transverse 019 Length of fourth 066 Proximal diameter, transverse 015 Median diameter, transverse 013 Anteroposterior diameter of condyle 014 Length of fifth 038 Proximal diameters I ""^^^P^^t"""' «'4 ( transverse 013 Anteroposterior diameter at middle .-. 009 Distal diameters ^ ^''*''^''P°^**"'"" 013 ( transverse 010 III. — Phalanges, Jirst row. Length of first 014 Proximaldiameterslst^^'*'''^'''''^ "^ C transverse 010 Distal diameters l8t I ^^^*i'=''l 006 ( transverse 006 Length of second 025 Proximal diameters 2d ^ "^®''*'*'^1 "12 transverse 018 Length of third 028 Proximal diameters ^ ^"^''^''^^ "12 I tr.ansverse 022 462 THE WASATCH FAUNA. M. Length of fourth 023 Proximal diameters 5 ^«''*''=*1 "" c transverse Olo IV. — Second phalanges. Length on third digit 017 Proximal width 017 Distal width 016 Distal depth 007 Length on fourth digit 015 vertical 010 Proximal diameters . „,. transverse . .Ulo V. — Ungual phalanges. Length of first 014 Proximal J d'^Pt'^ ""^ width 009 Length of second 022 P™i.aU'"P"' '"' i width 014 Width at shoulder 015 Length of third 024 „ . i^depth -• 010 Proximal I y I width oia Width at shoulder 019 Length of fourth 021 Proximal ?1«^Ptl^ ^"^ width 013 Width at shoulder 0145 Length of fifth 013 width 009 ^'°"*""M depth 008 Width at shoulder ^- 009 Bestoration. — The foregoing measurements show that this species was as large as a big-horn ; that its body was rather longer than in that animal, and its legs shorter and more robust. It was in fact proportioned more as in the common American tapir, but was of smaller size. The middle three toes of both feet reached the ground, while the first and fifth projected lat- erally and posteriorly, like the dew-claws of the hogs. The tail was longer and hpavier than that of any of the living hoofed mammals, resembling in its proportions that of the wolf. The eyes were small and the muzzle long, but was singularly soft above near the extremity. Whether this soft part was pierced by valvular nostrils, as in the hippopotamus, or was produced into a short proboscis, as in the saiga or in the tapir, cannot be certainly ascertained, but there are indications of the insertion of important cartilages, if not muscles, on the superior faces of the premaxillary bones. PHENACODUS. 463 The animal was probably omnivorous in its diet. It was not furnished with any weapons of offense or defense pertaining to the osseous system, so that it must have sought refuge in flight. The well-developed muscular insertions of its limbs, and the digitigrade character of its step, indicate that it may have had considerable speed. Distribution. — The bones of this species have been found wherever the beds of the Wasatch Epoch occur, but most abundantly in Northern Wyo- ming. From the Wind River Valley Mr. Wortman brought two specimens, and ten from the Big-Horn Basin. Synonyms. — Two names have been given to supposed species which may be identical with this one. These are P. omnivorus and P. trilobatus. The latter is considered under the head of the dentition. The former was founded on an inferior molar from New Mexico. It remains for future exam- ination to ascertain its true position. Phenacodus hemiconus Cope. Paleontological Bulletin, No. 34, p. 179, Feb. 20, 1882. Proceed. Amer. Philos. Soc, 1881, Dec. (1882), p. 179. Plate XXV e; fig. 16. Represented by the posterior two superior molars of an individual in- termediate in size between the P. primcevus and P. puercensis. The poste- rior molar is peculiar in the very rudimental character of the posterior inter- nal lobe, which is reduced to a mere wart on the cingulum. The posterior external tubercle is also rudimental, not exceeding the posterior inner in dimensions. The anterior tubercles, including the intermediate, are well developed, the internal exceeding the external. The cingulum is wide and crenate, and is only wanting on the external base of the crown. The pe- nultimate molar does not differ so much from that of P. primcevus, but the two internal cones are not so deeply separated at their base. The tubercles are all but little worn, and are conical in form, the external flattened on the external faces. Enamel wrinkled. Measurements. M. Diameter8 0fM.ii^'''^*^'"''P°^'«"°' '^ I transverse 012 Diameters of M. ill I '^'^^'^'■''P^st'^"'"' " '^l" t transverse 013 464 THE WASATCH FAUNA. The size of this species precludes the possibility of its identity with any of the other species described here. The Big-Horn Basin, Wyoming; J. L. "Wortman. Phenacodus voetmani Cope. Bulletin U. S. Geol. Surv. Terrs., F. V. Hayden, \j, 1881, p. 199; Paleontological Bnlletin, No. 34, 1882, 179, Feb. 20. Eyracotherium vortmani Cope, American Naturalist, 1880, p. 747. Phenacodua apternxis Cope, Paleontological Bulletin, No. 34, pp. 179, 180. Plates LVIIjr, LVIIA, LVIII; figs. 8-10. This was a rather abundant species in Wyoming during the Wasatch Epoch. The best specimen in my possession is a nearly perfect skeleton found by Mr. J. L. Wortman near the Big-Horn River in Northern Wyo- ming. This I now describe. Cranium. — Pressure has distorted the skull so that the superior surface is oblique to the sides, and the frontal region is a little crushed in. By viewing the two sides, however, a fair idea of the general form may be at- tained. The premaxillaries are not so produced as in the P. primcBVus, and they unite on the middle line at their extremity in a Gothic arch. The free portion of the nasal' bones is short, is somewhat contracted, and is obtuse at the extremity. The profile is probably nearly straight. The orbit is of moderate size, and extends as far forwards as above the first superior true molar. The facial plate of the maxillary bone is uniformly gently concave. The sagittal crest is well developed, of medium height, and commences at a point one-third way between the posterior border of the orbit and the supra- occipital crest. The latter is bilobate, moderately notched on the middle line, and the alee have not much transverse extent. It continues into the zygoma as the posterior temporal crest, and sends a distinct branch down- wards to near the extremity of the posttympano-paroccipital process. There is a small lachrymal tuberosity on the anterior edge of the orbit. The supraorbital border is rather thick, and terminates in a distinct short an- gular postorbital process, which is directed downwards. The zygomatic arch is not stout nor convex The orbital edge of the molar is a little flared outwards, and it supports no trace of postorbital angle. The post- glenoid process is prominent, is rather broad, with a convex inferior mar- gin. The meatus auditorius is widely open below. The posttympanic and PHENACODUS. 465 paramastoid processes are united into a short tuberosity with narrowed apex. Tlie occipital crest is curved backwards, and the surface between the external end of the occipital condyle and the lateral occipital crest is concave. The premaxillary bone exposes an external face of nearl^^ equal width, from the second incisor to its superior extremity at the anterior lateral edge of the nasal bone. Posterior to this point the premaxillary bone does not extend. The nasal bones expand posteriorly so as to occupy the superior facial surface just anterior to the line of the anterior border of the orbits. How far posteriorly they extend cannot be certainly determined in the fossil, but what looks like the fronto-nasal suture crosses the face just in front of the anterior border of the orbits. If this be the posterior boundary of the nasals they do not have such a posterior extension as in P. primcevus, although they are expanded in the same manner. The fronto-parietal suture apparently crosses the- superior surface just posterior to the line con- necting the postorbital processes. The anterior part of the malar bone is a band of equal width extending along the border of the orbit to the lachry- mal bone. The latter extends a little on the superior orbital border, and about equally far below and above the lachrymal tuberosity for a moderate width on the facial surface. The squamoso-malar suture is straight, and the two elements of the zygoma terminate each in an acute angle. The foramen infraorbitale opens above the middle of the fourth pre- molar tooth. The lachrymal foramen is within the orbit. Postglenoid foramen rather large, issuing in a groove of the postglenoid process. A postparietal, and a single mastoid foramen. A rather large foramen just within the position of a supraglenoid foramen, above the postglenoid pro- cess, and entering the squamosal bone posteriorly and inwards. Foramen magnum incomplete in the specimen. Mandible — The mandibular ramus is not deep. Its inferior outline is gently convex from below the last molar tooth to the symphysis, which rises very gradually to the alveolar border. The inferior edge below the coronoid process is concave, and the border of the angle is broadly convex, turning gently forwards before ascending to the condyle. The external angle of the latter is prominent, and sends downwards a low ridge which 30 c 466 THE WASATCH FAUNA. becomes the anterior edge of a beveled border of the convex angle of the jaw, which ceases on reaching- the inferior surface. The face of the con- dyle is transverse and narrow, and presents exclusively superiorly. The base of the coronoid process is narrow fore and aft. The masseteric fossa is well marked, excavating the ascending ramus above the line of the teeth; below this it is only defined for a short distance in front by a downward continuation of the anterior ridge. Symphysis not coossified. There is a single mental foramen, which is below the first inferior premolar. Dentition. — The first and second incisor teeth are very similar, and different in the form of the crown from the third. The crowns are ex- panded anteroposteriorly, so as to touch each other, although the roots are separated But there is a space nearly equal to the lengths of the edges of both crowns between those of the first incisors of opposite sides. Wearing makes the edges of the first and second acute. The third incisor is equal in size to the others, but its crown is canine-like, and with recurved apex. A short space separates this tooth from the canine, and the alveolar edge is arched upwards to receive the crown of the inferior canine. The canine is not large. Its crown has a spherical triangular section, the posterior edge not acute. The first premolar leaves a single rather large oval alveolus, which occupies the space between the canine and the second premolar. The latter has a simple crown, which is a triangle in profile. Its base is wider poste- riorly than anteriorly, but there are no accessory tubercles. • The anterior and posterior edges are subacute. The base of the crown of the second superior premolar is nearly a right-angled triangle, the posterior and exte- rior edges contributing to the right angle. The external face of the crown is flat and triangular in shape, a slight convexity indicating the basis of a small posterior external tubercle worn off by mastication. The internal cusp is also worn off. Its base is entirely posterior. The base of the fourth premolar more nearly approaches an isosceles spherical ti-iangle, the posterior border being a little more convex than the anterior. The external cusps have subequal bases, which have a round section on attrition. The internal cusp has a semicircular section on wear. There is space for a pos- terior intermediate tubercle, but if it were present, it is worn off. Anterior PHEXACODUS. 467 and posterior, but no external nor internal cingula. The anterior cingulum rises into an angle at the antero-exterior corner of the crown, which is not very prominent. Of the true molars the first and second are about equal and the third is considerably smaller. The external face of the second is more oblique posteriorly than that of the first. The third is an oval with the narrower end external. The external cusps are subequal and subround in section in the first and second molars, and the internal cusps are also subequal and subround. The intermediate tubercles are present except on the posterior half of the second molar, where it is wanting, agreeably to the more con- tracted space at that point. Both these teeth have cingula all round the crown excepting on the internal side. The external cingular tubercle is obtuse. In the third true molar the two posterior tubercles are much reduced in size, and there is no intermediate tubercle between them. There is one between the anterior paii-, which are of usual proportions to the crown. The anterior and exterior cingula are the only ob\aous ones on this tooth. The inferior incisors are directed very obliquely forwards, and have the crowns compressed and wider than the roots. The crown of the third is not certainly known. The crown of the inferior canine is directed straight upwards, is about the size of that of the upper jaw, and has a subround section at the base. The molar series is continued from it with- out diastema. The first premolar is a good deal smaller than the second, has one root, and a crown higher than long with its base rising forwards and its apex acute. The second premolar has a simple compressed conic crown with apex above the anterior root. The third has a similar form viewed externally, but is larger, and has a posterior face, which in its pres- ent worn state is a plane narrow triangle, with the base downwards. It is probable that in the unworn state of this tooth the internal tubercle was rudimental or wanting, and the heel very short. The fourth premolar has a large heel, and well developed internal and anterior tubercles. The ridges connecting the external posterior tubercle and the external median with the internal median and anterior, respectively, form two V's like the inferior 468 THE WASATCH FAUNA. molar of Bhinocerus. No internal posterior tubercle, so that the fourth premolar is unlike the first true molar. The first and second inferior true molars are subequal, while the third is smaller. The former support three posterior tubercles and two anterior opposite each other. The median posterior is smaller than the others, and does not give the posterior edge of the crown an angulate outline. The section of the interior tubercles is round; that of the exterior is crescentic, the anterior horn extending into a low "ridge which, in the case of the pos- terior tubercles, reaches the anterior inner tubercle. In the first true molar it extends round the anterior base of the crown as a wide ledge ; in the second and third molars this ledge is much less distinct. The median poste- rior tubercle of the third true molar forms a prominent heel, but its prom- inence is less obvious because of the proximity of the inner median tuber- cle which is not opposite the external median, but posterior to it. No cin- gula on the external or posterior side of the teeth ; inner side concealed by matrix. Measurements of shull. Length of cranium from apex of premaxillary bone to superior border of foramen magnum, inclusive; measured below 145 Liength from apex of premaxillary to a vertical line from end of nasal bone 0185 Length from end of premaxillary to anterior edge of orbit 064 Length from end of premaxillary topostglenoid process 116 Long diameter of meatus auditorius externus 006 AVidth of i)alate between canines 015 Width of palate between postglenoid processes, exclusive 027 "Width of occiput at foramen magnum 038 Width (least) at anterior iiarietal region 016 "Width at postorbital processes 036 "Width of interorbital space 035 Greatest width of anterior nares 013 Greatest depth at front of orbit (without molar) 036 Greatest width at zygomata 055 Length of mandibular ramus 110 Depth of mandible at condyle 042 Depth at heel of third true molar 020 Depth at second true molar 017 Depth at first premolar Oil Length on palate from premaxillary border to line of canine alveolus 019 Length of canine alveolus - - 0065 Length of molar series 053 Length of premolar series 030 Length of base of second premolar 0065 _,. . . T, ™ ...< anteroposterior 007 Diameters superior P-m. iii < . ^ „„^ * transverse 00b PHENACODUS. 469 Diameters superior p.m. ivj''°te™P°«'«™'^ '^O^^ M. 007 transverse 008 Diameters M. a ^ ^"te-'oposterior 008 \ transverse 010 Diameters M. iii «'i*''™P°«**^''"^ ^°^ c transverse 009 Length of dental lino of mandible 076 Length of base P-m. ii 0065 Diameters P-m. iii 5 anteroposterior 008 ( transverse 004 Diameters P-m. iv^^^t^ioPO^terior 009 ( transverse 0055 Diameters M. i ^interoposterior 009 ( transverse 0066 Diameters m. iii r^'"**''''?''^**"'"' 0^" i transverse 006 Elevation of crovpn of inferior canine ■ 008 Vertebrce. — The vertebral column is, probably, excepting the caudal series, complete. The dorsals are disarranged anteriorly, and the median lumbaTs are out of line, otherwise the centra are in place. There are seven cervicals, fourteen dorsals, seven lumbars, and three sacrals. Eleven cau- dals are preserved. The vertebrarterial canal is present on six of the cervical vertebrae. Their centra are moderately elongate, and a little opisthocoelous. The ar- ticular faces are oblique to the long axis, indicating the elevation at which, the head was held above the body. They are all obtusely keeled below, and the keel divides, forming a narrower or wider flat or concave triangular area Avith tuberous angles. The atlas is the shortest of the cervicals, and its neural arch is twice as wide anteroposteriorly as the inferior bar, and is fiat except a double tuberosity on the anterior border. The latter, viewed from above, is quite concave. The diaparapophyses are short, but wide anteroposteriorly. They are more extended transversely in their posterior half; their border contracts anteriorly, and the edge is a little wider. The vertebrarterial canal pierces it above and within its posterior border, and issues on the inferior face a little anterior to the middle. The artery notched the anterior base of the diapophysis and then pierced the neural- arch on the superior face equidistant between the diapophysis and the edge of the cotylus. The facets for the axis are distinct below, and have a slight angle on their internal edge. There is a small tuberculum atlantis with smooth truncate face. Centrum smooth below. 470 THE WASATCH FAUNA, The axis is of moderate elongation, and has a very oblique, slightly concave, posterior articular face. Its form is that of a deep semicircle, with a truncate protuberance below. The spine is produced obliquely upwards and backwai-ds, and is low in front. The postzygapophyses are large. The diaparapophyses unite into a short, acuminate backwards directed process, which extends to below the middle of the postzygapophy- ses. 'J'he atlantal facets are well turned upwards, and are hence deeper than wide. The odontoid process is cylindric, and its inferior articular surface is distinct from that of the atlantal surfaces. The inferior keel of the centrum is weak in front, but projects behind into the j^rotuberance already described. In four succeeding cervicals the articular faces of the centra are sub- round. In the third, fourth, and fifth the transverse process extends but little posterior to the posterior articular face, and the inferior edge does not descend to the level of the hypapophysial edge. On the sixth vertebra the diapophysial portion is directed u^jwards from the vertebrarterial canal, while the parapophysial portion extends almost vertically downwards, so that its horizontal inferior edge falls considerably below the hypapophysial line. On this vertebra also the neural spine first assumes important dimen- sions. The seventh cervical is mostly concealed by matrix. The zyga- pophyses in all the cervicals posterior to the axis are connected by a prominent but very obtuse ridge, and the roof of the postzygapophysis is thickened. The neural arches are quite flat on top. The modifications seen in the forms of the dorsal vertebra, as we trace them from before backwards, are the following: In the first vertebra the anterior articular is a little wider than deep; the relative width increases until on the posterior centra it much exceeds the depth. The usual change in the prezygapophyses is seen. On the first they are like those of the cervicals, horizontal and looking upwards and inwards; on the third they have already become sessile convexities, looking upwards and forwards, and it is not until the eleventh vertebra that they begin to resume the horizon- tal up-looking character. On the first dorsal the diajoophysis is robust and prominent, and has a large concave capitular facet. It is less prominent on the sixth, and has a subround extremity, and on the ninth it is surmounted PHENACODUS. 471 by a small metapophysis. On the twelfth the diapophysis is oval in sec- tion, and the metapophysis forms the external border of the prezygapophy- sis. On the thirteenth the diapophysis is short and flat, and the metapophysis is elevated. On the fourteenth the diapophysis is flatter and the metapophy- sis is an elongate process directed upwards and forwards. The centrum of the fifth dorsal is uniformly rounded below in transverse section, and a little concave anteroposteriorly. The dorsals become a little concave lat- erally as we follow them backwards, until the fourteenth becomes keeled below by the moderate excavation of the sides. The neural spines are quite elongate and slender on the anterior part of the column, and have the usual posterior slope upwards. On the twelfth the spine is first vertical, •wide, and truncate at the extremity. On the thirteenth and fourteenth the spines have, the posterior edge a little longer and more oblique than the anterior. The lumbar vertebrae continue the modifications of form already com- menced in the dorsals. The centra become larger and longer up to the seventh and last, which is a little shorter than the first lumbar. From the first to the last the articular faces of the centra increase in relative depth, the sides become more concave, and the hypopophysial keel more distinct, excepting on the last. Here the middle line below is more rounded. The posterior articular face of the last lumbar is not flattened as is frequently the case, but is but little wider than deep. The diapophyses are flattened and rather thin, and they originate from the anterior two thirds of the side of the centrum. The metapophyses are much elevated on all of the lum- bars excepting on the last, where they form only a prominent keel. The neural spine is preserved on the fourth lumbar. Its base is longer than on the dorsal vertebrae, is directed forwards as well as upwards, and the ex- tremity is rounded, not truncate. The neural spine of the seventh lumbar is more nearly vertical and its sides are parallel. The three sacral vertebrae are thoroughly coossified. The diapophyses form a narrow uninterrupted border, which is decxirved and expanded on the anterior vertebrae. The centra are rounded below. They diminish much in diameter posterior to the anterior or lumbar articular face. The distal articular extremity of the third and last sacral is only half the linear 472 THE WASATCH FAUNA. diameter of that of the last lumbar, and is subround, and somewhat oblique, the inferior border being the more prominent. Of the eleven caudal vertebrge preserved, five, and perhaps six, are con- tinuous from the sacrum. These diminish rapidly in bulk, retaining uniform length. The articular faces are subround; the anterior have them rather oblique, appropriately to the descending direction of the tail at the base. The diapophyses are present on the six, but very small on the sixth. They are depressed, acuminate, and turned backwards. The neural spines of the first and second are elongate but not elevated They are squarely truncate. The inferior face of the centrum of the first caudal is round transversely, and concave anteroposteriorly. On the second the middle line below is narrowed medially and expanded posteriorly. In the third this feature is more marked, the posterior expansion being concave medially. On the fourth and fifth there is a strong median rib, which divides into two poste- rior ribs, giving small surfaces for chevron bones. On the sixth the me- dian inferior rib is gone. Distal to this point the centra increase in length. The neural canal is reduced to a groove between two widely spreading tuberosities in front, and two closely approximated ones at the posterior ex- tremity. The diapophyses are represented by a small process at each ex- tremity of the centrum, of which the posterior disappears first. On the inferior face, the anterior extremity is more protuberant downwards than the posterior, and the median and chevron ridges are gradually effaced. In comparing this column with that of the P. primcevus, the principal differences are seen in the numbers of some of the series. In that animal the dorsals are probably fifteen, the lumbars are six, and the sacrals four. In the present species they are, dorsals fourteen; lumbars seven; sacrals three. The diff'erence in the number of the sacrals is more important than that of the lumbars and dorsals It is only necessary to shift one from the lumbar to the dorsal series in the P. primcevus, to have an agreement with the P. vortmani. The centra of the cervical vertebrae are a little shorter in the P. vortmani than in the P. primcevus, and the caudal diapophyses are more depressed and not so robust. The metapophyses are already distinct on the ninth dorsal vertebra in the P. primcevus, while they first appear on the twelfth in the P. vortmani. Diameters axial facet of atlas < Diameters of axis < PHENACODUS. 473 Measurements of Vertebrce. I. — Cervicah. U. Tot.al width of atlas 044 Diameters diaparapophvsis of atlas ^""^^^P"^*^™' ^^^ t transverse from foramen 008 vertical 0105 transverse at middle 009 transverse ^^*^*''''°*'^1^^'=*'*» °~^ < posteriorly 012 anteroposterior without odontoid 022 vertical posteriorly 0105 I third cervical 013 Length centra below, of J fourth cervical 013 I fifth cervical 013 I sixth cervical 013 [anteriorly J ^«^t'<=^l : 009 Diameters third cervical^ < transverse 010 I posteriorly ^^^^""al 0^04 L (transverse 012 Vertical diameter of neural canal of third cervical 0088 Expanse of postzygapophyses of third cervical 0216 Expanse of diaparapophyses of third cervical 0295 Total elevation posteriorly to base neural spine , 021 Diameters centrum sixth cervical in front ^ "vertical l 0086 ( transverse 010 Total elevation of sixth with neural spine 0274 Expanse of prezygapophj-ses 026 Expanse of diapophyses 029 Length of parapophyses from canal 0105 II. — Dorsals. Diameter centrum first dorsal in front^ vertical 0085 ( transverse .. 0115 Diameter neural canal of first dorsal in front < ' * " " — ( transverse 010 Expanse of prezygapophyses of first dorsal in front 0225 Expanse of diapophyses of first dorsal in front 0345 Elevation neural spine third dorsal from postzygapophysis 043 Length centrum fifth dorsal 014 Width of posterior face of centrum fifth dorsal 015 (anteriorly I ^«'^'<''*1 00^" Diameters eighth dorsal^ < transverse 0115 ( anteroposterior 015 Expanse of diapophyeis of eighth dorsal .026 Length neural spine do. from postzygapophysis 033 C anteriorly^ ^^-^'o^l 010 Diameters thirteenth dorsals < transverse 0135 ( anteroposterior 020 Total elevation with neural spine 0345 Diameters of neural canal ^ '^®'^''''*^ 008 ( transverse 007 Elevation of neural spine posteriorly 013 Anteroposterior diameter of spine at summit 010 Length of ceutrum of < 474 THE WASATCH FAUNA. III. — Liimbara and sacrum. M. ' first lumbar 020 fourth lumbar 024 sixth lumbar 025 ^ seventh lumbar 019 Diameters centrum sixth, in front, } '., ( transverse 014 Depth centrum seventh, posteriorly 0135 Total elevation of fourth lumbar 001 Elevation of neural spine of fourth lumbar from base 024 Length of sacrum - - 062 Diameters distal end sacral centrum J „,,'' ( transverse Oil IV. — Caudals. vertical 010 Diameters first caudal^ (transverse 009 C posteriori ( antei^oposti I posterior { 1^ < ( antei;oposterior 017 vertical 008 Diameters third caudal^' c transverse 010 ( anteroposterior 014 Expanse of postzygapophyses do 012 (posteriorly^ ^^^"•'^l °0^ Diameters sixth or seventh centrum^ < transverse 008 ( anteroposterior 018 ^ anterior j^''^""'^! 0085 Diameter centrum with two equal diapophyses^ ' transverse 008 ( anteroposterior 020 Length centrum without neural arch 022 Length of a distal centrum 019 y.— Totals. Length of cervical series 101 Length of dorsal series 236 Length of lumbar series 159 Bibs. — These are flattened proximally, but cylindi-ic for the greater part of the length. They are flattened again distally. The head is round and the tubercle oval, and looking forward, as well as upwards. Sternum. — The prBesternum is elongate, and the elongation is posterior to the articulation for the first pair of ribs, which is half as long again as the portion anterior to that articulation. At the articulation the posterior por- tion is depressed so as to be wider than deep. The posterior extremity is sub- equally quadrate. The costal articular facets are pedunculate and directed posteriorly. The anterior margins of the peduncles extend half way to the extremity, which is narrowly compressed. The inferior keel of this portion is not deep, and disappears posteriorly on the depressed base of the posterior PHENACODUS. 475 portion of the shaft. Three succeeding segments of the sternum are pre- served, which increase in width posteriorly. The last (fourth) is longer than wide, and flat, with truncate extremities. As compared with the sternum of the Phenacodus primcevus, the praesternum of the P. vortmani, is much less compressed posterior to the costal articulations, and the peduncles of the latter are more prominent. The fourth sternal segment in the P. primoevus is shorter and wider. I find no trace of clavicle in this species. Measurements of ribs and sternum, M. / from liead to tubercle 006 [ transverse) of tubercle 00o5 Widthsof fourtli rib^, ( of shaft near tubercle 0065 (^ anteroposterior at proximal fourth 0025 Length of 12th or 13th rib 109 Diameter of 12th or 13th rib at middle 0045 Length of presternum 0515 Length to posterior base of rib facet 023 Depth at anterior base of rib facet 009 Depth at posterior extremity 008 Width at posterior extremity 008 / c anterior 0065 \ ^Tl Tift VAf^ft / y\ Diameter second or third segments \ posterior Oil ( an teroposterior 022 , f anterior 0015 Diameters fourth or fifth segment 5 ''''"sverse^ posterior 013 ( anteroposterior 0195 The scajnila is like that of P. primcevus reduced in size. The oval glenoid cavity with anterior acumination separated by a shallow groove from a short subconic posteriorly turned coracoid process, is the same in both species. Both the scapulae are somewhat mutilated, so that while the pro- tuberance of the anterior edge above the neck is evident, it is not possible to know whether it is as much extended as in P. primcevus. One portion lost in that species is present in the specimen of P. vortmani; the acromial process. As in the AmUypoda and Proboscidea, the spine of the scapula is recurved, forming a prominent shelf along its proximal portion ; while the proximal extremity is extended forwards and downwards in a considerable acromion. As its extremity is broken off the length cannot be ascertained. This scapula resembles that of the Linocerata and Proboscidea, with an acromion added. This gives it very much the character of that of some rodents, as Sciurus. 476 THE WASATCH FAUNA. Measurements of scapvla. M. Totallength 106 Diameters of glenoid cavity ^^"^'''•''P'''*''™'" "^^ c transverse 012 Width of neck 0-30 Elevation or spine at acromion - Oil Length of coracoid from internal base 004 The humerus is relatively somewhat more slender than that of P. pri- mcBVUs. In its details it is much like that of that species, but differs in the following points : The head is rounded in outline, or not compressed as it is in some degree in P. primcevus. The subscapularis fossa is much less ex- tended anteroposteriorly, and is more oblique. The bicipital and epitroch- lear ridges are less prominent, and the epitrochlear bridge is rather longer. The three characters do not differ from those of P. primoevus. The tuberos- ities are well developed, though not produced as in most Diplarthra. The proximal external edge of the greater tuberosity forms a convex ridge. The anterior boundary of the smooth surface of the head becomes a ridge on the inner half, and ends in a low angular tuberosity in the fundus of the bicip- ital groove. The fossa teris minoris is large and impressed. The crista teris major is weak proximally, but becomes prominent at the proximal third of the shaft. It is continued downwards on the front of the shaft as the rather obtuse angular anterior edge. It is less prominent than in P. primcBVUs and Periptychus rhabdodon, and less evidently continuous with the deltoid crest than in many ungulates. The epicondyles are not very prominent, but the internal is the most so. The epicondylar foramen is rather larger than in P. primcevus. The condyles are not much extended transversely. There is considerable trochlear surface on the distal external side of the flange, and terminates in a fossa posteriorly. The roller is quite convex, and the posterior trochlear groove is wide, deep, and somewhat ob- lique. The ulna is stouter than the radius to near the distal extremities, where the long diameters are equal. The carpal extremity of the ulna is of course the most contracted. The ulna is however not so robust that the radius appears to cross it as in the Proboscidea, but it is compressed so as to be deep. The inferior edge is an angle, except at the extremity of the olec- ranon, and has a gently convex profile to about the middle of the length PHENACODDS. 477 when it rises and for the remainder of the length is slightly concave. Be- tween the humeral cotylus and this rise the shaft is triangular in section. Distad to this point is a compressed oval, since the external ridge descends to become part of the inferior border, forming an obtuse rib across the ex- ternal side of the shaft. The olecranon is rather long and compressed, with superior acute edge and concave internal side. It is about as deep as the deepest part of the shaft, and is thickened below and distally. The humeral cotylus is flared behind on the external side only, and below most on the internal side. Below the internal flare to the middle of the length the side of the shaft is gently concave. The distal extremity has a flattened tri- angular section, and terminates in a small rounded tuberosity. The radius is not much expanded at the head, and a horizontal section of its humeral surface is sigmoid, to suit the humerus. The external angle is obtuse and short, and turned slightly posteriorly. The shaft at its mid- dle is a little flattened horizontally; more distally it is cylindric. The dis- tal extremity is stout and not depressed. The superior tendinous groove is wide and shallow, while the supero-external groove is bettor defined by a short prominent longitudinal ridge below it. The articular surface is not so much contracted as in the P. primcevtis, and the facets are relatively wider anteroposteriorly. The scaphoid and lunar facets are faintly distinguished from each other, and in each the anteroposterior exceeds the transverse diam- eter. A small flat internal tuberosity and a similar posterior (inferior) one. Extei'nal tubei'osity larger and more prominent. Measurements of fore limb. M. Length of humerus 113 ( anteroposterior (greatest) . 032 Diameter of proximal end 2 c at bicipital groove 0155 ^ < at lesser tuberosity 021 Anteroposterior diameter of shaft at middle 013 Width at epicondyles 028 Width of condyles distally ' 019 Anteroposterior diameter of condyle^ ^^ ^^^^i J ■■ 01^ ( internally 015 Length of ulna 131 t extremity of olecranon 012 Depth of ulna at < corouoid process 019 ( middle of shaft 010 Diameters of distal tuberosity^ "^^ertioal 005 t transverse. 004 478 THE WASATCH FAUNA. M. Diameterof carpal facet I ^"•*'<=-''l ""^^ c transverse 008 Length of radius 090 Diameters of head of radius 5 "^^ertical 008 < transverse 015 Diameter at middle of shaft^ vertical. 006 ( transverse 009 Diameters of distal enlargement^ ' < transverse 015 T>- 4. J? 1 J- .( vertical (at lunar) 0075 Diameters of carpal facet < ( transverse Oil There is a similarity between Phenacodus and Hyrax in the proportions of the ulna and radius. The carpal articulation of the ulna is, however, quite different in the two. In Eyrax it is larger and more transverse, as in Meplias. It is also larger in Hyrachyus. In fact, it is in Phenacodus much like that of a carnivore. A part of the left anterior foot of this specimen is preserved. It is smaller than the posterior foot, the metacarpals and phalanges having smaller lengths and diameters. The thumb is as well developed as in the P. primcevus, so that the presence of five toes in the manus is demonstrated. But one bone of the carpus is preserved, the trapezoides. It differs consid- erably in its form from that of the P. primcevus, having a nearly quadrate anterior face, instead of a transverse one. It is considerably deeper antero- posteriorly than wide, and has not the navicular-like shape of that of the P. primcevus. On this account I compared it with the magnum, but in this genus that bone has the usual posterosuperior convexity and posterior tu- berosity. Both superior and inferior faces are concave anteroposteriorly. The posterior extremity is narrowed, and is recurved obtusely above, in an angle below. The head of the second metacarpal has the internal third defined as the facet of the trapezium. The free edge of this facet overhangs a little the first metacarpal in front, the latter fitting aa oblique groove of the second. To the third metacarpal, the second presents a crescentic facet, which is bounded below by a fossa. The shaft is not elongate, and the section is oval, the edge next the pollex being thicker than that next the third meta- carpal. Its distal extremity is about the size of that of the third, and larger than that of the fourth. Its keel is distinct and exclusively posterior, and is directed somewhat towards the tliird metacarpal. The first metacarpal is PHENACODUS. 479 small. Its distal extremity is cut off on the side next the M. ii, so that the keel is near the inner edge. The internal edge is oblique. The first pha- lange is rather elongate, The ungual has a round section near the base, and the lateral edge is but little developed. The first phalange of the second digit does not differ much from the corresponding piece of the posterior foot except in its inferior .size. The distal extremity of the third metacarpal is somewhat contracted, and does not have the flatness of that of the P. primcevus. Its posterior keel is thick, and directed a little towards the thumb. The first phalange of the third digit differs from that of the pes in its less depressed form and slightly reduced length. The actual proximal depth is a little greater, while both extremi- ties are distinctly narrower. Its distal ligamentous fossae are well marked. The distal extremity of the fourth metacarpal is truncate on the inner side and oblique on the exterior; the superior or anterior part of the condyle being as narrow as in a carnivore, but not bounded proximally by the fossa usually seen in that order. Keel distinct. The extremity of the fourth metacarpal is smaller than that of the sec- ond. Its external epicondyle is more prominent than the internal. The penultimate phalange is a little narrower than the corresponding one of the pes. Meastiremenfs of manus. ' u. ( anteroposterior 009 Diameters of trapezoi(les< c vertical 006 ^ anterior I j^^^g^gj^g ^053 Distal transverse diameter of M. i 006 Length of 1st xihalange of polles 008 Length of M. ii 0352 Distal diameters M.ii^"'^t'^'-°P°'^**"°'- OO'^ ( transverse 0095 Length of 1st phalange of M. ii 015 Distal diameters M.iii 5 •^"^^^P''^*"'"'" ' "O^ ( transverse 0082 Length of Ist phalange of M. iii 018 Proximal diameters of 1st phalange of M. iii J P C transverse 010 Distal diameters of 1st phalange of M. iii ^™t«'•°P''«*«"°'■ 005 (transverse 0072 Distal width of M. iv 008 The pelvis has an intermediate type of form. It has no resemblance to that of a marsupial or a rodent, but resembles rather that of a carnivore, as Canis and Ursits. It is in fact intermediate between that of those genera 480 THE WASATCH FAUNA. and Hyrax, the ilium more resembling that of the latter. It has no tendency to the triradiate type of the Biplartlira, nor of the expanded form seen in the Amhlypoda and Proboscidea. The infero-anterior edge of the ilium is longi- tudinally concave, though not so much so as in P. primceviis, since the ante- rior angle is not so much produced. Most of th'e thin edge of the crest is preserved, and it forms a regular curve of moderate convexity, largely parallel to the infero-anterior border. It contracts gradually to the apex, which is a short truncate thickened border. Posteroinferiorly the posterior edsre suddenly contracts to the wide neck. The infero-anterior edge is a flat edge of moderate width, which gradually expands at the neck to two-fifths the width of the external face. There is a rudimental anterior-inferior spine. The superior edge of the acetabulum marks the middle of the length of the innominate bone, as it does in P. primcevus. In Hyrax capensis it marks two-fifths the length from the tuberosity of the ischium. The latter is in Phenacodus vortmani strongly convex and not thickened. The spine of the ischium is a well-marked angle half way between the anterior edge of the acetabulum and the tuber ischii. The intei-nal superior angle of the innominatum is obtuse opposite the acetabulum, and not expanded as in many Diplartlira. The pubes are lost excepting the symphyseal portion. This is considerably thickened, and the longitudinal median keel is dis- tinct. This is crossed by an angle parallel to the acute anterior border of the pubes which is caused by a bevel of the antero-inferior face. The ischio- pubic symphysis is narrow, indicating, with the form of the ischium, a large obturator foramen. , Measurements of pelvis. m. Total length through acetabulum 157 Length of ilium to acetabulum 079 Width of plate of ilium at middle 030 I interiorly 014 Width of peduncle < anteroexteriorly 010 ' posteroexteriorly 019 Diameter of pubis at b.a8e^''°t*''°P''«*''™y^y ^2, I anterointemally 0043 Length of obturator foramen - 038 Width of ischium at spine 019 Width ischium at middle of obturator foramen 015 Diameters of acetabulum ( ' " c anteroposterior - 020 The posterior limb is more slender than that of the P. primceviis. The tibia is a little longer than the femur, which equals the length of the innom- PHENACODUS. 481 inate bone to the posterior edge of the obturator foramen In P. primoevus the tibia is a little shorter than the femur, and is six-sevenths the length of the innominate bone to the posterior edge of the obturator foramen. The femur has mnch the character of that of P. primcevus, including the transversely oval form of the head, and the large third trochanter. The long axis of. the proximal extremity makes an angle of 45° with the long axis of the distal extremity, but the long axis of the head is parallel with that of the distal extremity. It therefore does not coincide with the long axis of the proximal extremity. The latter is at right angles to the long axis of the proximal extremity of the great trochanter. The latter is ob- liquely truncate, so that its external angle is as high as the head, and the internal angle is longer than the head. The latter sends down a strong ridge which bounds the large trochanteric fossa posteroextemally. The small trochanter is prominent. The rotular groove is rather narrow and elevated, and the internal ridge is a little more prominent on its convexity than the external. The internal condyle is narrower than the external. The latter has a fossa just external to the edge of its anterior portion. At its posterior base the face of the shaft has an external shallow fossa, and an internal rib. The former is bounded externally by a faint ridge which extends towards the great trochanter. Other than this there is no trace of linea aspera. The patella is short and robust It is truncate above, and acuminate below. Anteriorly it is convex with two proximal lateral facets. The tibia is rather slender. The crest is moderately prominent, and continues as the obtuse angular front of the shaft. Its superior extremity is truncate downwards. The spine is not prominent. The cotyli of the head are not very unequal ; the internal longer fore and aft, the external longer transversely. The posterior face below the head is concave, with equal lateral bounding ridges. The internal ridge is the more acute, and continues as the angular internal edge of the shaft to near the distal extrem- ity. The internal edge of the head is acute ; the external edge is truncate in front of the fibular facet. The long axis of the distal extremity makes an angle of 35° with the long transverse axis of the head. The astragalar grooves are on the contrary parallel to the long anteroposterior axis of 31 c 482 THE WASATCH FAUNA. the head, and hence oblique to the long axis of the distal extremity. They are deep and with rounded fundus. The posterior apex of their dividing ridge is equally produced with the anterior angle, which is just exterior to the end of the dividing ridge. The internal malleolus is truncate below, and a little more produced than the two angles in question. The inner side of the internal malleolus is nearly flat, and but shallowly concave. The head of the fibula is expanded anteroposteriorly. The shaft is slender and subround in section. The distal extremity is less expanded than the proximal, and its transverse and anteroposterior widths are equal. It has two distal faces; one oblique for the astragalus, the other transverse and free. The tendinous groove of its external face is only marked by a short prominent ridge on its anterior border. Measurements of posterior limb. m. Total length femur from head 133 Length to line of middle of third trochanter 049 Length to internal rotular crest 106 Diameters of head ^ ^""S •<'^^ c short at middle 013 I proximally 036 Total width femur < at third trochanter .024 ( below third trochanter 013 Greatest width of condyles 028 Depth of condyle at inner rotular crest 038 I longitudinal , 020 Diameters of patella < transverse 015 ( anteroposterior above Oil Total length of tibia 143 ; anteroposterior at internal cotylus 034 Diameters of the head \ anteroposterior at popliteal notch 025 ( transverse 030 Anteroposterior diameter of shaft at distal third 010 Diameter of distal end of tibia ^'^°t®™P''^*«"°^(S^«''t««*) 018 ( transverse 018 Length of fibula 128 Proximal diameter anteroposteriorly 014 Diameter of middle of shaft 005 Distal diameter ^ ^°*«^°PO«t«"»' O^l^ ( transverse 010 Besides its greater slenderness, the tibia of this species differs from that of P. primcevus in the greater obliquity of the astragalar grooves. In the latter species, the internal malleolus is more protuberant, and not truncate, as in the P. vortmani; and the anterior face of the distal end is flatter. The posterior foot is almost entirely preserved. The astragalus is a diminutive of that of P. primoevus, having the trochlear groove profound and the neck elongate. It differs from it in having the trochlear ridges less PHENACODUS. 483 unequal, and the head not so flat and laterally extended. The depth of the navicular face is two-thirds the transverse length, while in P. primcevus it is about half the same. Its convexity is flattened in the P. vortniani, but entirely convex in P. primoevus. Its surface is strongly recurved on the internal side as in that species. The median fossa of the internal face of the trochlear portion is distinct. The inferior anterior angle of the external side of the same is flared outwards, as in P. primcevus. The calcaneum, like the bones of the leg, is rather more slender than that of P. primoivus. It resembles that element of the latter in most respects, but the cuboid face does not present the internal angle, but is truncate next the astragalus. It is quite oblique, both in the transverse and the vertical direction. The cuboid is like that of P. primcevus, but is less robust. The navicular also resembles that of the same animal. The part of its distal face which is applied to the ectocuneiform is convex, to fit the proximal con- cavity of that bone. Its posterior down-looking tuberosity is well devel- oped. The ectocuneiform and mesocuneiform are relatively more elongate than in P. primcevus. The latter is quite flat in P. primcevus, but its length in P. vortmani equals its width at the second metacarpal. On the other hand the entocuneiform is shorter than that of P. primcevus, and its inferior border is compressed, and little or not at all truncate. The metatarsal facet is, on the contrary, quite strong in the P. primoevus. The metatarsals are all rather more slender than those of P. primcevus. The fourth is as long as the calcaneum in P. vortmani, but is shorter than that element in P. primcevus. When in place it is not quite as much pro- duced as the second in P. vortmani; in P. primcevus it reaches the same point on the third. The second is produced proximally more than the others, and hence has a lateral facet for the ectocuneiform. The relative lengths of the toes are, beginning with the shortest, I, V, IV, II, III, as in P. pri- mcevus. The fifth is half as long as the third; it has two proximal articular facets; one lateral, the other proximal for the cuboid. The first has a sin- gle narrow proximal facet. The distal articulations are not so stout as in P. primcevus, but the distal posterior keels are well developed. The ligamen- tous fossse are well defined. The first metatarsal is somewhat flattened, and its shaft is divergent 484 THE WASATCH FAUKA. from that of the second. The proximal extremity of the shaft is obliquely- truncate where it is in contact with tlie concave side of that of the second. The inner part of the extremity is an anteroposterior tuberosity. The head of the second metatarsal is also somewhat obliquely directed inwards, and there is a low tuberosity on the external edge of the shaft just below it, which fits a fossa of the applied edge of the third metatarsal. • The distal extremity is less flattened than that of the first, but is narrower than in most three-toed ungulates. The phalanges of the proximal set are rather elongate, and are flat. Their distal extremities are narrower than the proximal and are depressed, the articular faces not being recurved to the superior surface. Distal liga- mentous fossae strong. The phalanges of the second set are longer than wide, and less robust than those of P. primcevus. Their distal articulations are more recurved. Four ungual phalanges are preserved in a fair condi- tion. They are rather narrow, and display the inferior proximal subtri- angular table without lateral groove. Extremity notched; inferior surface concave. That of the hallux is short and subconic. Measurements of posterior foot. To.. Total length of foot • 148 Length of tarsns 058 Length of median digit 043 Tarsus. Length of calcaneuin r 045 Depth at heel _. 012 Width at sustentaculum 019 Depth at astragalar condyle - 009 Diameters of cuhoid facet < ' " „,„ ( transverse OW Length of astragalus on inner crest (total) 023 Length of astragalus on outer crest (diameter trochlea) 0125 Width of trochlea, including crests Oil External elevation of troclilea Oil Diameters of navicular face J ^^""^'i t transverse 012 ( longitudinal 006 Diameters of navicular bone j . c anteroposterior 014 ^ < transverse 017 f proximal ^■'"t«''"P''«t''"«"^ °^" If transverse Oil longitudinal (median) 014 median^ "°*'"'"P"^**"°'' °!^ I transverse 010 PHENACODUS. 485 M. c anteroposterior 010 Diameters of entocuneiform< vertical Oil ( transverse 007 Anterior vertical diameter of mesocuneiform 0055 Uroximal^''"'«''°P''^*''"°'^ '^^ Diameters of entocuneiform< I transverse 003 ( longitudinal 008 Metataraug, Length of first 022 Anteroposterior diameters 5 P''°^°»''"y ''*^ (distally 006 Length of second 047 Proximal transverse diameters 008 Distal diameters^ ''"t^^P''**^™' "08 < transverse 0085 Length of third 048 Proximal transverse diameters 009 Width at middle of shaft 007 "Width at above condyle (greatest) , 0095 Distal diameters 5 '"''"^"P"^*'^"'"" ^^ < transverse 009 Length of fourth 044 Proximal diameters ^ ''"^^'•"P"^*'^"'"' "1" < transverse 006 Median width 005 Distal diameters ^^"*«™P°«t''""'- ^^ < transverse 008 Length of fifth 035 Proximal diameters I ''°**'^°P°^*"''»"' ^^ i transverse 0055 Anteroposterior diameter at middle 004 006 006 Distal diameters! anteroposterior. < transverse Phalanges of fore or hind foot. First row. Length of first (or fifth) digital 010 Distal diameters of first (or fifth) digital \ vertical , 003 ( transverse 004 Length of second digital 018 Proximal diameters of second digital I '^'^''tical 006 ( transverse 0095 Distal diameters of second digital J "^'ertical 0045 c transverse 007 Length of third digital 020 vertical 007 Proximal diameters of third digital ( transverse Oil Distal diameters of third digital \ ^"rtical 005 c transverse 008 Length of fourth digital ; 015 .009 .006 Width of fourth digital \ Pi'»simal . ^ < distal.... 486 THE WASATCH EPOCH. Second series. H. Length of third digital 012 Proximal diameters < ^^^ical 006 transverse 0085 Distal diameters 5 ^^^t'^^l ^^ c transverse 008 Ungual phalanges. Length 014 vertical 0055 Proximal diameters , „ < transverse 0O7 It is, unfortunately, not possible to determine whether the phalanges above measured belong to the anterior or posterior foot, owing to the fact that they were associated with a collection of the bones of both in one por- tion of the slab containing them. The bones of the posterior foot as far as the phalanges, were continuous, while those of the metacarpus were want- ing. It is, therefore, probable that these phalanges belong to the posterior foot. Besides the specimen above described, Mr. Wortman brought portions of four mandibles from the Wind River bad lands, and twelve from those of the Big Horn. Restoration. — The limbs of this species are rather elongate for an eocene mammal, and the anterior limbs are distinctly shorter than the pos- terior. The size of the animal is that of a bull-dog, but the head is smaller, and the neck rather shorter, and not nearly so robust. The limbs have about the same proportions to the body as those of a bull-dog, but the ante- rior ones are shorter. The proportions of the parts of the limbs, and of the fore and hind limbs to each other, excepting the feet, are much as in the collared peccary. The feet of tlie latter animal are longer than in Phenacodus vortmani. We can thus imagine the Phenacodus vortmani as an animal of the com- pai'atively slender build of the hull-dog, with a neck and head proportioned 'more as in the raccoon, and with the rump more elevated than the withers, • as in the peccary. The feet resembled those of a tapir or rhinoceros, but had a pair of short toes on each side, which did not reach the ground. To this add a tail much like a dog's in proportions, and the picture is complete. The diet of this animal was omnivorous, with a smaller proportion of animal CONDTLAETHEA. 487 food than the hogs, for instance, use. The food is more hkely to have re- sembled that of the quadrumana. What means of defense this species had is not easily surmised, as the canine teeth and hoofs are not large. I have named this species after Mr. Jacob L. Wortman, of Junction City, Oregon, whose explorations in the West have been more than usually productive of important results. Phenacodus calceolatus Cope. Proceeds. Amer. Philos. Soc, 1883, p. 559. Plate XXIV g; fig. 7. This species is founded on fragments of the skull and limbs, with teeth, of a single individital. The teeth consist of two superior and four inferior molars of one side, and a smaller number of those of the opposite side. The teeth are of the size of those of the Phenacodus puercensis, and, like that species, there is no median external cingular cusp of the superior molars. In these teeth the external basal cingulum is weak, but there is a strong anterior cingulum, distinct from any of the cusps. No internal cin- gulum. External cusps conical, well separated; intermediate cusps rather large; internal cusps rather large, close together, but deeply separated. The last superior molar is reduced in size. It has well-developed anterior and posterior cingula, a weak external and no internal cingula The intermediate tubercles are rather large, and there is one large internal tubercle. The heel of the last inferior molar is short, wide, and rounded. The posterior tubercle is but little behind opposite the posterior internal tubei'cle. The latter is separated from the anterior inner by a deep fissure, while the opposite side of the crown is occupied by a large median exlemal cusp, which has a semicircular section. The large anterior cusps are confluent on wearing. No anterior cingulum in the worn crown. The crowns of the first and second true molars of the specimen are rather worn. They show that the posterior median tubercle is very indistinct and probably absent The bases of the smaller inner cusps are round, and on wearing unite with the larger external cusps. Of the latter the posterior is the larger. Anterior cingulum rudimental or wanting. No lateral or posterior 488 THE PUEECO EPOCH. cingula. The principal peculiarity of the lower dentition of this species and the one from which it is named, is the form of the third or fourth (probably third) premolars, both of which are preserved. They have a compressed apex, which descends steeply to the anterior base, without basal or lateral tubercle. The base of the crown spreads out laterally behind, and is broadly rounded at the posterior margin, so as to resemble the toe of a wide and moccasined foot. It is depressed, the surface rising to the apex from a flat base. Measurements. Diameters of second superior molar )'*°t''r°P''*t«"'"" 0080 ( transverse 0100 Diameters oflast superior molar ^ '*"**"■"?"«*«"<"■ 0067 I transverse 0085 Length of inferior true molars 0258 Diameters of M.ii^'*°*^'""P°^*<^"*'^ 009 ( transverse 008 DiametersofM.iii^^"**™?''^*^"""' 0086 ( transverse 0068 Diameters ofthePm.iii I ''"t'^'^^Po^t'^"'"- 008 ( transverse 005 About the size of the P. puercensis. Phenacodus puercensis Cope. Proceeds. Amer. Philoa. Soc, 1881, p. 492. Paleontological Bulletin No. 33, p. 492, Sept. 30, 1881. Plate XXV e; figs. 12-13. LVII/; figs. 8-9. In the Paleontological Bulletin No. 34 I combined this species with the P. vortmani, which it greatly resembles in size and proportions. It is an abundant species in the Puerco formation of New Mexico, and I have recently secured numerous jaws with teeth. Among these there are six fragments of maxillary bones with molars. I find, on comparing these with the true P. vortmani of the Wasatch beds, that they uniformly differ in the absence of the external tubercle which rises from the cingulum opposite the space between the principal external cusps. In this respect they re- semble the Protogonia subquadrata. The difference is important, and I an- ticipate that other characters will be found confirmatory of the distinction of the species here maintained. Typical specimens have the following characters: Last superior molar smallest; first and second true molars with six CONDYLARTHEA. 489 tubercles, two external, two median, and two internal. A strong basal cin- gulum, except on inner side. Inferior true molars, besides the usual five tubercles, furnished with an anterior ledge with a tubercle at its interior extremity. A weak external basal cingulum. A little larger than the P. vortmani. Length of superior true molars, M. .021 ; length of base of crown of M. iii, .006 ; do. of M. i, .008 ; width of do., .008; length of base of crown of inferior M. iii, .0085; width of do. in front, .006 ; depth of ramus at M. i, .019. There is some variation in the form of the smallest superior molar, some being nearly round and others suboval in outline. Two mandbular rami with molars represent smaller individuals. They measure as follows : Length of bases of last four molars, M. .033 ; do. of true molars, .02.5 : length of crown of inferior M. iii, .0082. Depth of ramus at M. ii, .«*«"°' 0070 t transverse 0046 Depth of ramus at Pm. ii 0100 Depth of ramus at M. ii 0128 From the Big-Horn Wasatch formation ; J. L. Wortman. Phenacodus zuniensis Cope. Paleontological Balletin, No. 33, p. 492. Sept. 30,1881. Proceeds. Amer. Philo. Soc, 1881, p. 492. Plate, LVII/; fig. 10. This is the smallest species of the genus yet known. It is represented by many mandibular rami, the best preserved of which supports the last four molar teeth. In the last ta'ue molar the anterior external cusp is larger than any of the others. There is a minute anterior inner. The external lateral is the apex of a crescentoid crest; the corresponding inner one is smaller, and is part of the raised border, which culminates in a small median tubercle pos- teriorly. The first and second true molars are narrowed in front, and there is no distinct anterior ledge, only a minute anterior inner tubercle. The external cingulum is more distinct and the enamel is wrinkled. The fourth premolar has a short base, and the inner cusp is much smaller than the prin- cipal one ; it has a wide heel and an anterior basal tubercle. Length of true molars, M. .018; of last true molar .006; of first true molar .006; width of do. .004; depth of ramus at do. Oil. The anterior border of the masseteric fossa is well marked to the mid- dle of the depth of the ramus. The fossa is elsewhere undefined. From the Puerco epoch of Northwestern New Mexico; D. Baldwin, 492 THE WASATCH EPOCH. DIACODEXIS Cope. American Naturalist, 1882, p. 1029. (Dec. 2 (»).) Inferior and superior molars tubercular; the superior with interme- diate tubercles, but no external cingular tubercle. Principal external cusps subconic; the anterior internal cusp continuing into the anterior interme- diate on trituration. There are four superior premolars, of which the posterior three have two external cusps. The third and fourth have well- developed internal lobes. The inferior premolars and molars are unknown, except the last true molar. This has distinct cusps, not joined by crests, and a prominent heel or fifth lobe. It is yet to be positively determined whether this genus belongs among the Condylarthra or with Pantolestes in the suilline Artiodactyla. It somewhat resembles Dichobime, but differs in the absence of the interme- diate crescentic lobe of the superior molars, and the development of a trans- verse crest on wearing. These teeth are in fact like those of the Perisso- dactyla, and this fact, together with the bunodont type of the true molars, induces me to place the genus provisionally in the Phenacodontidce. But one species is known, which is from the Wasatch formation. DiACODEXIS LATICUNEUS CopC. American Naturalist, June 1882, p. 1029. (Dec. 2(?).) Phenacodus laticiineus, Paleontological Bulletin No. 34, 1882, p. 181. Plate XXVe; figs. 17-18. This is a small species, and is represented by six superior molars and the last inferior molar in a fragment of the lower jaw. The latter tooth ex- hibits peculiar characters already mentioned. The superior molars differ from those known to belong to the Phenacodus primmvus and P. puercensis in having a vertical fissure of the inner side which separates the bases of the two internal tubercles. This gives them some resemblance to the superior molars of the species of AnisonclmSy. but the important difference remains in the separation of the anterior inner tubercle from the inter- mediate tubercles. The three are confluent into a V in the genus last mentioned. The external cusps of the superior molars are rather acute, and lentic- CONDYLARTHRA. 493 ular in section, their external sides forming a convex rib There is no nb between the external sides. There is a strong anterior cingulum, which terminates externally in a low angular cusp. Thei'e is no cingulum on any other part of the crown. The second, third, and fourth premolars have two external cusps, and much resemble the corresponding teeth in Hyraco- therium. The second is longer than wide, and has an internal ledge; the third is as wide as long, and has a wide internal ledge; the fourth is wider than long, and has an internal and two intermediate cusps, and an anterior and posterior cingulum. They all have a weak external cingulum, of which a trace exists in the true molars. The last inferior molar has a double anterior inner cusp, as in some Mesodonta, and the external anterior cusp is robust. All the cusps are conical and with round section, and their bases are close together. The outline of the base of the crown is almost an isosceles triangle with rather wide base in front. Measurements. M. Length of last six superior molars ^ .0350 Length of true molars • 0160 Diameters of M.ii^'*°*""P°*t^^''''^ «055 t transverse 0080 Long diameter base of Pni. ii 0050 Diameters Pm. i;; ^ anteroposterior 0060 ( transverse 0060 From the Wasatch beds of the Big Horn River, Wyoming; J. L. Wortman. MENISCOTHERIUiAl Cope. Eeport on Vertebrate Fossils from New Mexico; U. S. Geog. Geol. Survey W. of 100th Meridian, 1874, p. 8. Report U. S. Geogr. Geolog. Survey W. of lOOtU Meridian, 1877, Vol. IV, Pt. II, p. 251. American Naturalist, 18S2, p. 334. As already indicated, with this genus we enter a new family of the Condylarthra, and one which superadds to its general structure a consider- able specialization of the molar teeth. The present genus is the only one of the family yet known, and it is represented by but three species. With present knowledge it must be asserted that the range of this genus was limited both in time and space. The remains of the species have been de- rived from the Wasatch beds of New Mexico, and from a horizon from near its base, which overlies the Puerco. The genus has not been found in any 494 THE EOCENE PERIOD. other of the areas of the Wasatch deposits, but it occurs abundantly in its locahty, so that it is possible to determine its general structure. a i» -I A q Dental formula, I. ^- : C. - : Pm. - ; M. - ; without diastema. Inci- 3 1 4 '6 sors and canines in both jaws small. Fourth superior premolar unlike first true molar. Fourth inferior premolar like first inferior true molar. Third inferior true molar without third lobe or heel. Superior incisors with small oval crowns. Inferior incisors with short depressed crowns. First and second superior premolars without internal lobes. First, second, and third inferior premolars without internal lobes. True molars supporting two external Vs, which are separated by a vertical ridge. Two internal lobes ; the anterior conic, the posterior crescentic, the anterior horn of the cres- cent connecting with a central intermediate lobe, so as to form an oblique cross-crest on wearing An anterior intermediate lobe forming a crescent concentric with the anterior V. Last superior molar without the posterior internal V. Fourth superior premolar with two external Vs, two interme- diate lobes,, and an internal cone. Third superior premolar with external wall and internal cone. First inferior premolar one-rooted; third, two-rooted, with compressed crown. Fourth premolar and true molars consisting of two Vs, whose adja- cent limbs join each other. Inferior canine incisor-like. Orbits widely open posteriorly. Palate excavated between the molars posteriorly. A postglenoid process. Auricular meatus widely open below. Posttympanic and paroccipital processes united. Occipital and sagittal crests. Foramen ovale scarcely separated from / lacerum anterius. Man- dibular symphysis coossified. Mandibular condyle uplooking. Brain not so small as in Phenacodiis. The cervical vertebrae are, like those of Phenacodus, of medium length, and slightly opistheocoelous. They, with the lumbars, have an inferior keel. The disparity in size between the anterior dorsals and lumbars is marked. The odontoid process is cylindric. Metapophyses of lumbars well marked. No anapophyses. The neural canal is rather large. The head of the scapula has a curved coracoid process. The spine rises abruptly from the neck. The humerus is much like that of Phenaco- CONDYLAETHRA. 495 dus or a carnivore. The tuberosities are not produced, and thero is no external epicondyle. The internal is large, and sends upwards the bridge that incloses the epicondylar foramen. The pelvis is not well preserved in the specimens. It shows a rather narrow, triangular neck, a well-marked anterior inferior spine, and an open acetabular groove. The femur shows a fossa ligamenti teris, and the third trochanter on the middle of the shaft, and well developed. The tibia has an anterior crest, and no notch on the antero-external edge of the head. The internal malleolus is a prominent tuberosity, and the astragalar face is scarcely grooved, and oblique, as in the Creodonta. The distal extremity of the fibula articulates with the sides of the astragalus, but not with the cal- caneum. The calcaneum much resembles that of Phenacodus. It is elon- gate, and the astragalar facet is not longitudinal, but very oblique. The astragalus has trochlear keels of unequal height, and a shallow groove between them, much less marked than in Phenacodus, but not so flat as in PeripfycJms. The neck is elongate, and the distal articular surface is con- vex in every direction. The number of toes in Meniscotherium is unknown. Metapodial bones preserved are rather narrow, leading to the supposition that the digits are similar to those of Phenacodus and Periptychus. The posterior keels of the distal extremities of the metapodials are distinct. Three species of this genus are known to me. They may be distin- guished as follows : Length of last four molars, M. .034 M. terrcerubrw. Length of last four molars, M. .029 . M. chamense. Length of last four molars, M. .024 M. tapiacitis. The superior molars of this genus have some resemblance to those of Hyopotamus, but the inferior molars are different, and of the Anchitherium type. The temporary last molar differs from its successor, the permanent fourth premolar, in its more complex character. It is in fact identical in structure with the true molars. The second and third milk molars differ from their successors in their greater anteroposterior extent. The third has an internal lobe opposite the posterior half of the external wall. 496 THE EOCENE PERIOD. Meniscotherium terr^rubr^ Cope. Paleontological Bulletiu No. 33, p. 493, Sept. 30, 1881. Proceed. Amer. PliUos. Soc, 1881, p. 493. Plate XXV/, figs. 12-14: XXV 3. I have parts of skeletons of many individuals of this animal, but each one in a very imperfect condition. It is practicable from these to learn the osteology of the species, but in using the measurements it must be borne in mind that there is some range of variation in the different individuals. A specimen with both jaws crushed in a limestone nodule displays two superior incisors. They are short, and a little expanded laterally. The second has median angle and an external oblique edge. On the third the apex is at the internal angle, and the edge is all external and oblique. Surface smooth. Measurements of incisors.. M. Length of crown of superior I. i 004 Width of crown of superior 1 004 Length of crown of superior I. ii 005 Width of crown of superior I. ii 004 Length of inferior true molars of same 025 In a second specimen the superior molar series is most complete. The dimensions of the superior molars increase to the penultimate, while the external and posterior sides of the last molar are contracted, re- ducing its size. The external faces of the external Vs of the true molars are considerably impressed; those of the premolars are nearly flat. The second premolar is two-rooted, and has a compressed crown, with- out either heel or cingulum, except a thickening of the posterior base. The base of the crown is triangular. The external plate of the third pre- molar is simple, and is connected with the internal cusp by a cingulum on the posterior base of the crown. The crown is transverse, and the inner tubercle rather small. Tlie fourth premolar is much larger than the third. Its external plate is divided into two apices, which are not impressed. Their external faces are separated by a faint ridge and are divided medially by a faint ridge. The anterior external angle is rather prominent. The anterior and posterior cingulum extend to and round the inner base of the interior tubercle. Within the anterior external apex is a well-developed intermediate crest parallel to it; and there is a corresponding crest within COXDYLAETHRA. 497 the posterior external apex. This one turns inwards at its posterior ex- tremity, which is on the posterior cingulum. The anterior angle or horn of each external crescent of the true molars is very prominent. They are sections of short vertical ridges, which unite near the base of the crown, giving abruptness to the impression of the external surface of the anterior lobe. The middle of each face has a faint median ridge. The two molars have an anterior basal cingulum, but no posterior or internal, excepting a trace between ■ the bases of the internal lobes. The anterior intermediate crescent is quite parallel with the ex- ternal; the anterior internal tubercle has a slightly V-shaped section. The posterior inner tubercle is quite confluent with an oblique intermediate crest, as in 31. chamense. In the last true molar, as there is only one internal tubercle, this crest is short, terminating at the posterior border. The last true molar is like the last premolar, except in its two impressed external crescents. Enamel smooth. Measurements of superior molars. M. Length of superior molars, less Pm. i 046 Length of true molar series 028 Length of base of Pm. ii .' 005 Diameters of base Pm.iii^^'^t'''-"P«^t'^"'"' 006 ( transverse 007 Diameters of base Pm. iv ^ ^"**=^°P°^*«"°' 008 < transverse 010 Diameters of base M. ii 5 anteroposterior Oil c transverse 013 There are some variations in the characters of the fourth superior pre- molar. In the specimen above described, which is the one on which the species was based, the external face of the crown is uninterrupted, and there is a weak cingulum round its internal base. In another specimen there is a narrow vertical ridge distinguishing the two lobes on the external face, as is found in the true molars, but less developed, and the internal cingulum is strong In another specimen with the external ridge, there is no internal cingulum. A characteristic of this species is the great contraction of the pre- molar series. This condition in an imperfect specimen led me to suspect in first describing the species that the fourth inferior premolar was only the third. The inferior incisors, canines, and premolars form an uninterrupted 32 c 498 THE EOCENE PEBTOD. series. The incisors are subequal, and have flat crowns, projected obhquely forwards. The crown of the canine is but Httle larger than that of the third incisor. It is not canine-hke, but has a compressed cx'own, which is inclined forwards, and has therefore an oblique base. The superior edge consists of a long posterior and short anterior portions. The crowns of the first and second premolars are compressed conic, convex in front, and straight behind, the second with a minute heel. The root of the latter has a figure 8 section; its two elements not being separated. The third pre- molar is a large tooth, and the crown consists of an anterior compressed obtuse lobe, and a wide heel, with a median cutting edge. There is a small anterior basal lobe, and the interior side may be vertically grooved behind it, as in various Artiodactyla, but not necessarily. The fourth premolar is abruptly very much larger than the third, and is as long as the first true molar, and a little naiTower anteriorly. In details of structure it is exactly like the true molars. The internal extremities of the posterior branches of the Vs composing the infei"ior molars rise into an acute cusp. The anterior branches of the Vs, on the other hand, are curved backwards, partly closing the open mouths of the Vs. The resulting pattern on wearing is a good deal like that of the AnchitJierium. The anterior limb of the anterior V is a little more produced in the fourth premolar. The last true molar is like the others. No cingula. * Measurements of inferior teeth. M. Length of dental series, including canine 055 Length of true molar series 027 Length of alveolus of canine 0025 Height of crown of canine OOC Length of crown of third premolar 0058 Diameters fourth premolar 5 «"t«^°P°«*'^"*'^ °^ ( transverse 006 erior 0092 00G2 Diameters second true premolar < '^^ ^ropos ( transverse Several fragmentary crania are preserved. The best of these lacks the muzzle and the zygomata. This one is remarkable for fullness of the frontal region, the profile descending from it both anteriorly and posteriorly. The brain-case is not narrowed, but the muzzle contracts rapidly. The orbits are lai'ge and the malar bones prominent. Their posterior border is indi- CONDYLAETHEA. 499 cated by postorbital angles only; there are no zygomatic angles bounding them below. The former rise into strong temporal ridges, which rapidly con- verge and unite to form a low, straight, and narrow sagittal crest. The pari- etal bones over the hemispheres are convex in all directions, and posterior to them are a little concave, where the surface rises posteriorly into the supra- occipital crest. This projects upwards, and, being concave in the middle, has a bilobed outline, though not so strongly as the Periptychus rhabdodon. The occiput is concave on eacli side above the position of the condyles. The lateral crest continues into the posttympanico-paroccipital crest, which is incurved on the inferior base of the skull as far as the occipital condyle. The basioccipital has a faint median keel. Thebasisphenoid is flat. Between the postglenoid and the foramen ovale there is a small concave face, which extends from the anterior base of the zygoma to the external meatua on the inferior surface. On its interior edge is the base of the styloid process. In front of the latter its border is cut by the large foramen ovale, which is not cut off from the foramen lacerum. The palate is doubly excavated posteriorly to opposite the middle of the anterior external lobe of the third superior molar. The infraorbital foramen is large, and issues above the middle of the fourth superior premolar. There are three postparietal foramina, serially arranged, the anterior on the squamosal suture. There are three supra- sqamosals, also lineai-ly placed, the last near the parietal suture. Thex-e are two inferior squamosals near the base of the zygomatic process, one above the other. The nasal bones widen posteriorly, but not so much as in the species of Phenacodus. Their posterior outlines are acuminate. The malar bone extends to the lachrymal. The lachrymal foramen is not external to the orbit. Palate rather concave. Frontal region slightly concave in transverse section. The mandible is contracted forwards. The symphysis is narrowed, flat, and at the incisor teeth nearly horizontal. The rami are compressed and rather robust. The coronoid processes are elevated, and have nearly vertical anterior edges. The angles are produced posterior to the line of the condyles and are broadly rounded. The basal part is compressed and thin, but the posterior edge is thickened and projects inwards opposite the line of the molars. The condyles are close to the posterior base of the cor- 500 THE EOCENE PERIOD. onoids, and their superior articular face extends to the coronoid. The ex- ternal expansion is semicircular in outline, and extends to the base of the coronoid anteriorly. The internal expansion is triangular, with the apex decurved and continuous with the posterior edge of the condyle. The artic- ular surface descends on the latter, occupying the interior half of the con- dyle. There is no ridge or tuberosity below the condyle posteriorly as in many perissodactyles. The masseteric fossa is shallow, and only defined by the low anterior ridge. This ceases rather abruptly at the middle of the depth of the ramus below the last molar. The internal pterygoid fossa is not marked. The inner edge of the base of the coronoid is rather prominent. The dental foramen enters a little below the tooth line. There is one men- tal foramen, which is below the first premolar. Measurements of skull. M. Length from canine to foramen magnum, inclusive 089 Width of skull at base of zygoma 063 Width of palate between fourth premolars 017 Length from occipital crest to beginuing of sagittal crest 039 Length from occiput to line of anterior border of orbits 0C35 Width at pos'orbital angles 012 Width at auricular meatus 034 AVidth of nasal bonces behind (both) 020 Width of sphenoid at foramen lacerum 010 Width of foramen magnum 0085 l)i-l>th of skull (without molars) at front of orbit 034 Length of mandibular ramus (tot.al) 099 Length of ramus to base of coronoid 066 Depth of mandible at condyle 048 Depth of mandible at coronoid 053 Depth of mandible at last molar 017 Depth of mandible at fourth premolar 015 Depth of mandible at canine 006 The lower jaw above described belongs to the same individual as the skull, but lacks the condyles. These I derived from a perfect lower, which has the good series of teeth which furnished the description of them already given. For vertebrae recourse must be had to still other specimens. The axis and third cervical veriebrce are so much like those of Phenaco- dtis vortmani that the description of them will apply to these. They are somewhat smaller. The inferior keel terminates posteriorly in a tiiangular table with concave middle in both. The articular surfaces are very oblique, CONDYLAETHEA. 501 indicating the elevation at which the head was held. The neural canal is large. Another specimen, or set of specimens of equal size, found together, furnish three cervical, seven dorsal, seven lumbar, the sacrum, and three caudal vertebme. These are accompanied by mandibular rami of three in- dividuals of identical dimensions. The first peculiarity observable in these vertebrae is the more than usually increased size of the lumbars. Were not the intermediate grades present, the dorsals and lumbars might be supposed to belong to different animals. The centra of the dorsals are depressed and a very little opisthocoel; their inferior surface is regularl}' rounded trans- versely, and a little concave anteroposteriorly. Tlie anterior lumbars are similar, but larger. The posterior lumbars are not elongate, as in Phenaco- dus and Hyracotherium, but have the same proportions as the dorsals. They are depressed, and are strongly keeled below. The sacrum includes only three vertebrae, whose centra are much depressed. The diapophyses pos- terior to the first, form a continuous ledge interrupted only by the interver- tebral foramina. The proximal caudal vertebral centra are as stout as those of the dorsal vertebrae and indicate a tail, stout at the base. In the following measurements all the vertebrae measured are from the lot above described. Measurements of vertehrw. M. Length of axis without odontoid 016 Expanse of axis at atlautal facets 019 Diameters posterior face centrum \ ' „„ ( transverse 0095 S posterior^ ^"■t''=^l - 008 Diameters centrum of a cervical < < transverse 010 ( anteroposterior 009 Height of neural arch 007 Expanse of postzygapophyses 019 Uosteriorly^^^"^"*^! 0063 Diameters of an anterior dorsal < < transverse 0085 ( anteroposterior 009 Uosteriorly^^'-^tical 006 Diameters of a posterior dorsal < c transverse 0095 ( anteroposterior 010 ^ posteriorly ^ ^«'-"'=''l ••" 006 Diameters of an anterior lumbar < {transverse 012 V anteroposterior Oil . . 1 < vertical 008 , posteriorly I Diameters median lumbar \ I transverse 015 anteroposterior 012 502 THE EOCENE PEEIOD. u. Uo8teriorlyr«rti'=^l 008 Diameters posterior lumbar < < transverse 015 ( anteroposterior 015 Height of ueural canal 006 Expanse of metapophyses 018 Length of sacram .038 vertical .006 transverse 013 I * •„ 1 < vertical 0065 \ posteriorly I Diameters of first caudal < (transverse 010 ( anteroposterior - 010 c Diameters anteriorly { t The glenoid cavity of the scapula is an oval, acuminate anteriorly to an apex pi'ojecting downwards. The coracoid is prominent, and strongly in- curved. Length of cavity, .009; width, .006. From a different individual from the one last described. The humerus is much like that of PJienacodus vortmani, differing in the smaller size, less prominent tuberosities, and slightly different condyles. The shaft is flattened anteroposteriorly below the head, but there is no bicipital ridge, and the groove is restricted to the notch between the tuber- osities. The latter project little, the gi-eater not at all anteriorly, but it rises proximally into a convex crest. The teres minor fossa is flat, and the teres major ridge is distinct and extends on the proximal two-fifths of the length. The subscapularis fossa is small and flat, and is bounded by an angular ridge which rises upwards and outwards, forming the prominence of the lesser tuberosity. The external epicondyle is wanting. The inter- nal is prominent and compressed, and sends a bridge over the epitrochlear foramen. The latter is as large as in the Creodonta, larger than in the spe- cies of PJienacodus, but not so large as in PeriptycJms rhabdodon. The crest of the external distal region is acute, but not very prominent. The shaft above the coronoid fossa is triangular, the anterior angle obtuse, the exter- nal acute. The condyle has an internal flange, and external to that a prom- inent rim not seen in Phenacodus nor Periptyclms. It is represented by a short cylinder in Biplartlira generally, and the edge of it is turned up in Hyracotlierium venticolum. In the M. terroeruhrm it is a rim springing directly from the contraction of the roUei', on the anterior side only. The convexity of the roller is marked, but too wide to be an intertrochlear crest, such as is seen in Hyracotherium and other Biplartlira. As compared with the Phe- nacodus vortmani, this humerus has a generally weaker structure. CONDYLAETHEA. 503 Measurements of humerus. Length of hmmerus 092 e anteroposterior (greatest) 024 Diameters proximally < transverse 5 ''* bicipital groove 015 V (at lesser tuberosity 019 Diameters of shaft at middle ^^"t^^P''^'^"'" ^^^^ ( transverse 007 Width at epicondyles 023 Width of condyles distally 015 / externally 010 Anteropoaterior diameter of condyles < internally 013 ( at constriction 008 The above described humerus is from the individual which furnished the vertebrae. It inchides also femora, tibiae, and a calcaneum, which I now describe. The femur is rather robust. The heads are unfortunately lost from the specimen under consideration. The trochanters are evidently prominent. The third trochanter commences above the inferior termination of the lesser trochanter, and the base extends much below it. The patellar trochlea is prominent; the external condyle is a little wider than the internal, and less prominent. There is a fossa at its posterior base, while the inner has a shallow one on the middle of its side. The tibia is a characteristic bone. It resembles considerably that of Phenacodus, but differs in many points. First, the crest is not obliquely truncate next the head, but is fully rounded. Second, it extends farther doAvn the shaft, terminating rather abruptly a little above the middle of the latter. Third, the ridge which is its continuation, twists abruptly to the internal edge of the sliaft, leaving the anterior face flat, instead of continu- ing down the middle of the front of the shaft, and turning a little outwards below. Fourth, the early disappearance of the external posterior angle, and its reappearance on the distal two-fifths of the length, and termination in an angle of the astragalar surface. Fifth, the disappearance of the pos- terior external angle on the middle of the length of the shaft. The posterior face of the shaft on its distal half is roughened for muscular insertion. ^ The roughened area naiTows upwards, and terminates in a narrow apex. Sixth, the obliquely truncate internal malleolus, which is acuminate as in 504 THE EOCENE PERIOD. many Creodonts. The long axis of the astragalar face is slightly oblique to the transverse long axis of the head, tending backwards towards the inner side. In this respect it is identical whith Phenacodus vortmani. In Hyra- cotheriuni venticolmn the two axes are parallel. The tibia is much smaller than that of Phenacodus vortmani, and with the femur, prove that the pos- terior limb is little if at all longer than the anterior limb, as is the case in that species. The patella is an elongate oval, less robust than that of Phena- codus vortmani. It is rounded above and narrowed below. Measurements of hind leg. M. Diameter of head of femur No. 1 0115 Length femur No. 2 from base of little trochanter, distad v , 059 Leugth femur No. 2 from inferior base of third trochanter, distad 049 Width of condj'les posteriorly 023 Elevation of rotular groove at external condyle 024 Width of rotular groove with crests 0095 Length of patella 016 Proximal diameter patella ^^°*''^°P°«*«"°'' ^'>'' ( transverse 0085 Length of tibia 097 Diameters of head ^='"t«''°P°«t''"'"- «20 c transverse 023 Diameters of shaft at middle ^'^"**^°P°^*^''''"' • 0°^ ( tr.ausverse 0065 Diameters distal end ^'*"t''™P"-^*''"°' 0^95 < transverse 012 The ealcaneum is remarkably elongate, and is but little expanded an- teriorly. The free portion is compressed. The astragalar condyle has a peculiar position. It is placed diagonally across the middle superior ridge of the free portion, and presents its articular surface chiefly forwards. The sustentaculum is deep, short, and narrowed to a knob. The cuboid facet is concave vertically, and very oblique transversely, retreating on the inner side. Its form is subquadrate, with the sides oblique, and the superior and exterior angles produced and rounded. The latter marks the extremity of the external distal ridge, which extends from the calcaneal condyle. Numerous astragali are preserved, but none accompany the specimen which has furnished most of the skeleton above described. This bone in this species looks much like that of a species of Stypolophus. The inner CONDYLARTHRA. 505 trochlear crest is much less elevated than the outer, and is obtusely rounded. The inner side of this part of the astragalus is oblique, and has a centi-al fossa and a prominent shelf-like angle below it. The external face is ver- tical; it is separated by a groove from the concave calcaneal facet below. The trochlear groove is shallow, and extends to the inferior face posteriorly, after a posterior interruption by the ligamentous fossa. The sustentacular facet is a long oval, isolated all round. The neck is long and diverges from the axis of the trochlea. The navicular face is oblique to the base of the astragalus, in the same direction as the trochlea, but more so. It extends a little on the internal side to a point. On the external side the articular surface does not extend so far posteriorly, and is broadly rounded. In common with the entire astragalus, it is depressed. Measurements of tarsus. M. Length of calcaneum 0215 Deptb of calcaueum at middle 009 Depth of calcaueum at astragalar condyle 0116 Width of calcaneum at sustentaculum 014 „. . 1 • 1 i- i (vertical.. 009 Diameters cuboid lacet < ( transverse 009 Length of astragalus (total) 020 Length of trochlea on external side 0115 Height of trochlea on external side 0085 Width of trochlea at middle above 0085 Width at trochlea below 013 vertical 007 Diameters head , < transverse 009 The phalanges preserved are flat, much like those of Phenacodus. Ungues not obtained. Restoration. — This species was about the size of a fox, but with a very different physiognomy. The profile was curved, the muzzle short, and the eyes large. The body was not so slender as in Phenacodus or a fox, having the more robust proportions of a raccoon. The fore and hind legs were rather short, and of equal length, so that the rump was not elevated as in the peccary. There was a large tail. The species is one-third (linear) larger than the Hyrax capensis. It was probably a vegetarian. The Meniscotherium terrceruhrce differs from the M. chamense in two 506 THE EOCENE PERIOD. features. The first is its superior size. The second is the flattened form of the external faces of the true molars and the absence of the convexity of the external bases of the crown. There is some variation in size. A few specimens apparently belong to a smaller race, whose last four superior molars measure M. .032. All the specimens of this species in my possession were obtained by D. Baldwin in the Wasatch beds of New Mexico. Meniscotherium tapiacitis Cope. Proceed. Amtr. Pbilos. Soc, 1882, p. 470. Plate XXV/, fig. 15. The species now to be described is a good deal smaller than the 31. chamense, and a fortiori than the M. terrcerubrce. It is known to me from the nearly entire rami of a single mandible. These support the last five molars of one side or the other, and alveoli of two others and of the canine tooth. Two characters besides the small size are observable in this jaw. First, the symphysis has not the shallow convex inferior outline in transverse sec- tion, but is on the contrary angular, having subvertical sides separated from a convex middle by a rounded angle. The symphysis is thus deeper than in M. terrcerubrce. Second, the crown of the third inferior molar tooth has the form of that of the second of the 31. terrcerubrce. It is anteroposteri- orly short, and has no keel nor anterior basal lobe ; its section is lenticular, and profile subconic. In 31. terrcerubrce this tooth is elongate; with well developed keel and anterior lobe. The alveolus of the canine is relatively larger than that of the 31. terrcerubrce. The coronoid process does not rise so close to the last molar tooth, nor so steeply, as in the latter species. The posterior recurvature of the internal extremity of the anterior limb of the posterior V of the true molars is but little marked. Measiirements. M. Length of true molars ou base 018 Diameters M. ;; 5 ant'^«PO«terior 006 transverse 0038 transverse 0044 _.. , „ ...anteroposterior 0065 Diameters M. "> ^ '■ AMBLYPODA. 507 M. „. , „ ...(vertical. 0045 Diameters Pm. m ^ ' auteioposterior 0U4 Wiiltli of inferior face of symphysis 008 Depth of ramus at Pm. lit 009 Depth of ramus at M. iii t'103 This species was obtained by Mr. D. Baldwin from beds of probably lowest Wasatch age, in New Mexico. AMBLYPODA. Cope System. Cat. Vert. Eoceue New Mexico, U. S. Geog. Siirvs. W. of lOOtliM., 1875, p. 28. Keport do. iv, pt. ii, p. 170. Mammalia Avith small (! smooth) cerebral hemispheres, which leave the olfactory lobes and the cerebellum exposed. The feet short and planti- grade, with numei'ous (in the known genera five) digits, terminating in flat hoof-bearing ungual plialanges. The seven bones of the carpus distinct; the unciform articulating with the lunar as well as with the cuneiform. The astragalus flat, Avithout trochlear groove, and attached to the tibia with little freedom of movement; its distal extremity divided into two facets, one for the navicular, and more or less of the other for the cuboid bone. Molars invested with enamel, with wide ci'OAvns and crests. A post-glenoid process. The above characteristics are the only ones which can, in the author's estimation, be admitted into the ordinal categorA , for although the animals embraced in the Amblypoda present many other pecitliarities, tliey are sitch as may readily vary within the limits of an order, and in fact do so in the families of many of the orders known to us. The above definition displays a double set of afiinities, viz: those indicated by the structure of the feet, and those expressed by the type of the brain. The former exhibit a close resemblance to the feet of the Prohoscidea, the approach being greatest in the hind foot. The principal difference in this extremity, is seen in the extension of the navicular articulation over the entire distal end of the astragalus in the Prohoscidea, Avhile in the Amhhjpoda, the navicular is shortened, tlius permitting the cvxboid to come in contact with the external part of the distal extremity of the astragalus. The I'ulfoid v.^ alike in the two orders, having considerable transverse extent, and suppovting the 508 THE WASATCH AND BRIDGER FAUNiE, external two metacarpals on its distal face. This lengthening- of the navic- ular is a specialty of the Proboscidea among hoofed Mammals, the shorter form being characteristic of the lower types of both Perissodactyla and Artiodactijki, where the astragalus has two distal articulations. In the Perissodactyla, the extent of the navicular increases until the highest genus, the Horse, is reached, where it almost covers the entire end of the astraga- lus; but, in the Artiodadyla, the extension of the cuboid over the astragalus does not diminish. The nearest approach to the distal articulation of the astragalus of the Amblypoda, outside of the order, is seen in the Miocene Perissodactyle genus Symborodon. Here the cuboid and nlivicular facets are flat, and are separated by an oblique line, so as to be similarly incapable of hinge-like movement. The resemblance to the lowest Artiodadyla {e. g., Oreodon, Hippopotamus) is very remote, for there the two facets are parallel, offering a ginglymus to the articulating bones. The difference between the fore foot of the Amhlypoda and that of the Proboscidea consists in the alternating position of the elements of the two carpal rows. This is also a character of the two other living orders of hoofed Mammals, and maintains itself with great persistency in both of them. It is essentially a primitive character, the alternating position being usual in the cold-blooded Vertebrata, and is the pereistence of the oblique relation of the original divergent branching rays, to which digits have been traced. In the Proboscidea and Hyracoidea, the elements of the two rows assume an opposite and longitudinal relation. The stnicture of the fore foot in the Amblypoda appears to be about equally related to that of the Proboscidea, the Perissodactyla, and the Artiodactyla. In the cubito-carpal articulation, the resemblance is again to the Proboscidea in the relatively large proportion of it belonging to the ulna, and the consequent lateral position of the latter bone. In this respect, it differs much more from the other two living orders of hoofed Mammals, although here again the lower forms of both resemble the Amhlypoda more than do the higher forms. As is well known, both of the hoofed orders display a constantly diminishing extent of the ulno-carpal aiticulation, and increase of the radio-carpal, until, in the Horse and Ox, the ulna becomes a mere splint attached to the radius. AMBLYPODA. 509 The relationships indicated by the brain are to the lissencephalous orders CJdroptera, Insectivora, and Edentata. As an ungulate oixler, the Amhhjpoda are distinguished from the first two, were other characters wanting. We may here notice, however, some curious resemblances between the forms of the teeth and lower jaw of Conjphodon and Bathjopsis and some Insectivora, and the still more curious resemblance between the tibio-tarsal articulation in the order and that of the cotemporary Creodont allies of the Insectivora. Comparison with the Ungulate forms oi Edentata only is necessary, and from these the enamel sheathing of the teeth sepa- rates the Amhlypoda at once. The small size of the brain doubtless relates these animals to the other Eocene Ungidata described by Lartet, still more nearly than to existing Lissencepliala. In the small size and smoothness of the hemispheres, and relatively large development of the optic and olfactory lobes, the brain of the Amhlypoda more nearly resembles that of the Creodonta than that of any division of recent animals. The resemblance between the brains of Amhlypoda and those of the Carnivorous Arctocyon {fide Gervais) is so great as to testify to a similar degree of cerebral develop- ment in both the clawed and hoofed types of Eocene Mammalia. As a resume of the relations of the Amhlypoda, it may be said that they are the most generalized order of hoofed Mammalia, being interme- diate, in the structure of their limbs and feet, between the Prohoscidea, the Perissodactyla, and the Artiodactyla. This fact, together with the small size of the brain, places them in antecedent relation to the latter, in a systematic sense, connecting them with the lower Mammalia with small and smooth brains, still in existence; and, in a phylogenetic sense, since they preceded the other orders in time, they stand in the relation of ancestors. It is doubtless true that the Amhlypoda were the ancestors of all living Ungu- lates, although no genus of the latter can yet be traced to any known genus of the former, such genera remaining for future discovery.* Stand- ing in this antecedent relation, comparison with other classes of Vertehrata is in place. The proportionate size of the brain is, in the Dinocerata, as has been discovered by Marsh, more like that characteristic of many * A discussion of these and other general relations of the Amhlypoda may be found in a paper read by me hefore the American Association for the Advancement of Science, August, 1875, and published in the Penn Monthly Magazine, December, 1875. 510 THE WASATCH AXD BEIDGER FAUN^. Reptiles than of Mammals, and I have shown that the immovable tibio-tarsal articulation is a Reptilian feature as well. These are, however, but hints of a relationship doubtless very remote. Before proceeding to a more detailed consideration of the genera of this order, I give the distinguishing characteristics of the two suborders into which they naturally fall: I. A third trochauter of the femur, and fossa for the round ligament; no alisphenoid canal; superior incisors present . . Pantodonta. II. No third trochanternor fossa for the round ligament; an alisphenoid canal; no superior incisors .' Diiwcerata. The differences presented by these suborders are thus very decided, but they agree in some important points, not necessarily of ordinal value. Thus the foramen ovale is distinct from the foramen lacerum anteritis, and the meatus auditorius is not closed inferiorl}^. In the first point, they agree with Symhorodon and Rhinocerus more than with any Proboscidea or Artio- dactyla. In the latter respect, thej^ agree with the Tapirs and Bhinoceridae, but not with other Ungulates. The cervical vertebrae are short, and not united by ball-and-socket joint, and are intermediate in character between those of Proboscidea and other Ungulates. In both suborders, the scapula is acuminate at its superior border and expanded behind, as in Pro- boscidea, wh;le the abrupt origin of its spine is a character of Proboscidea, Artiodactyla, and many other Mammals, but not of PerissodactyJa. In the rudimental spine and crest of the tibia, we have again especially Probos- cidian resemblances, which are confirmed by the shape of the ilium. This bone expands immediately from the acetabulum into a broad plate, which has a continuous convex crest, and is altogether different from the pedun- culate ilium of the Rhinoceros and Hippopotamus. As regards the points in which the suborders difter, it may be observed that the Pantodonta in their dentition and femur resemble the Perissodactyla more than do the Dinocerata, while the absence of alisphenoid canal in Coryphodon is a suilline character, and the only one which I find in the group. In the form of the femur, the Dinocerata resemble closely the Proboscidea, but in the presence of the alisphenoid canal they agree with both Perissodactyla and Proboscidea. It is not unlikely that, in future, AMBLYPODA. 511 genera will be found which connect both these orders more nearly with primitive types o£ Artiodadyla, but as yet we are not acquainted with them. The order Amhhjpoda was first defined by the writer in the Systematic Catalogue of the Vertebrata of the Eocene of New Mexico, published, in April, 1875. The two suborders Pantodonta and B'mocerata were originally defined by the writer in "The Short-footed Ungulata of Wyoming", pub- lished March, 1873, in the following language: "No incisors; nasal bones elongate; astragalus articulating with both navicular and cuboid ; no third trochanter Dinocerata. ''Dentition comiilete, i. e., incisors present; ? nasal bones; astragalus articulating with both navicular and cuboid ; a rudimental third trochanter Pantodonta f The name Dinocerata was then proposed as a correction of '^Dinocerea," originally introduced by Professor Marsh* for the animals which it includes, under the belief that it constituted a distinct order of 2IammaUa, which, however, he did not characterize. Shortly afterward (Januarj-, 1873t), I gave the first general synopsis of the characters of the species of the group then contained in my collection, in which they resemble the Prohoscidea, as follows: "1. The shortness of the free portion of the nasal bones; 2. The malar bone is rod-like, and forms the middle element of the zygomatic arch; 3. The cervical vertebrae are exceedingly short and transverse; 4. The femur is without third trochanter; 5. Its condyles are contracted, and the naiTOw intercondylar fissure is prolonged far forward; 6. The spine of the tibia is wanting, and the glenoid cavities separated by a longitudinal keel; 7. The astragalus is not hourglass-shaped above, but with a uniform face; 8. The phalanges are short and stout, and represent several toes." To these may be added two external characters, which directly result from the osteological, viz: 9. The possession of a proboscis; this is proven by the extreme shortness and stoutness of the free portion of the nasal bones, by the very short cervical vertebrae, and by the fact that the nasal and pre- maxillary bones are deeply excavated at their extremities, with surrounding osseous eminences for the origin of the muscles of the tnmk; 10. The extension of the femur below the body, so that the leg was extended with *Amer. Jour. Sci. and Arts, 1872, October, 167'1 (separata September iT). tThe extra copies of this paper, -which contained all except the character number "1", were published January 16. 512 THE WASATCH AND BEIDGEE FAUN^. the knee below and free from the body, as in Elephants, Monkeys, and Men. Other characters common to the Proboscidea and some other Ungu- lates are: 11. The scapula acuminate above the spine, and with a very short coracoid; 12. Broad truncate occiput, with widely separated temporal fossae: 13. The greatly expanded iliac bones." These characters were adduced in support of the view that these animals should be refeiTcd to the Prohoscidea. Although I have subse- quently referred them to a new and special order, the above characters express the affinities which I claimed for the group, although several of them are found not to be common to all the species. Thus the characters of the malar bone and cervical vertebrae are not common to all of the Dinocerata, while these, with the characters of the femur, are not found in the Pantodonta. It was not, however, until a few weeks afterwards that I discovered the near affinity between these suborders. As regards the possession of a proboscis, there is every reason to believe that some of the species possessed one, though it may have been short as in the Tapir, while it is possible that in others it was wanting, or not more developed than in the Hog. The first attempt to define the Dinocerata as an order of Mammalia was made hy Prof 0. C. Marsh, of New Haven, in a paper published a short time subsequently* to my essay quoted above. The characters which he brought forward, and which had mostly already appeared in the descriptions of species published by him and by myself, are the following: "1. The absence of upper incisors; 2. The presence of canines; 3. The presence of horns; 4. The absence of large aii--cavities in the skull; 5. The malar bone forms the anterior portion of the zygomatic arch; 6. The presence of large post-glenoid processes; 7. The large perforated lachrymal forming the anterior portion of the orbit; 8. The small and horizontal nareal orifice; 9. The greatly elongated nasal bones; 10. The premaxillaries do not meet the frontals; 11. The lateral and postei'ior cranial crests; 12. The very small molai- teeth and their vertical replacement; 13. The small lower jaw; 14. The articulation of the astragalus with the navicular and cuboid bones; 15. The absence of a true proboscis." * The extra copies of this paper bear date January 28, 1873. AMBLYPODA. 513 This heterogeneous list of characters could not define any natural group, as many of them are of not more than generic or family value.* Several of the most important are not shared by the genus Cori/phodon, a form at that time unknown to Professor Marsh, but which clearly belongs to the same order of Mammalia. My conclusion has been that the Dinocerata do not alone constitute an order of Mammalia, but that they form a division of an order which includes also Cori/pJiodon, and doubtless many other still unknown types, whose position is, as I first stated, between the Prohoscidia and the Perissodactyla, but which has no affinities with the Artiodactyla, as has been asserted. Full descriptions of the species and genera of this order first appeared in my essay, "On the Short-footed Ungulata of Wyoming", above quoted (published March 14, 1873). I there described the existence of five toes in the pes of the genus Eohasileus, and the co-ordinal relations of Corypho- don (Bathmodon). In a note published by Professor Marsh, October, 1873, that author asserts that the Dinocerata have "but four toes in the pes"; but in a paper on Uintatherium (JDinoceras), which subsequently appeared, he admits that that genus has five toes in the pes (Am. Jour. Sci. and Arts, Feb., 1876). We owe to later observations of Professor Marsh two of the most important points in the structure of the Dinocerata, viz, the supei-ficial structure of the brain, and the arrangement of the bones of the carpus. He shows {I. c, July, 1874, and February, 1876) that the cerebral hemi- spheres are so small as not to cover any part of the olfactory lobes and the cerebellum; that their surface was nearly smooth, and that their combined diameter was less than that of some parts of the neural canal of the vertebral column. The brain is relatively the smallest among known Mammalia, and resembles strongly that of the Creodont Arctocyon of the French Eocene, figured by Professor Gervais, in the "Archives du Museum", 1870. I sub- sequently showedf that the brain of Coryplwdon presents similar characters. The structure of the carpus of Uintatherium, described by Marsh {I. c, February, 1876), is essentially identical with that of Coryphodon, which I * As I pointed out in an article in the American Naturalist, May, 1873. t My description of the brain of Coryphodon appeared in the Proceedings of the American Philo- sophical Society for March, 1877, and was published April 25th. Professor Marsh's description appeared in the July number of the American Journal of Science and Arts for July, 1877, which appeared near the middle of Jane. 33 C 514 THE WASATCH AXD BRIDGE R FAU?f^. described in the Systematic Cataloo^ue of the Vertebrata of the Eocene of New Mexico (April, 1875). The Pantodonta are confined, so far as discoveries extend at present, to the Lower Eocene or Wasatch beds, in tlie Rocky Mountain region, while the Dinocerata are confined to the higher or Bridger Eocene strata. The former suborder includes three genera, Bathmodon Cope, Coryphodon Owen, and Metalopliodon Cope; the Binocercda four, Batlujopsis Cope, Uintathe- riiim Leidy, Eohasileus Cope, Loxolophodon Cope. I have anticipated* the discovery oi Amhlypoda with tubercular teeth No such have yet been found, but the probability of such discovery remains as strong, in my opinion, as at the time I ventured to suggest it. PANTODONTA. As already pointed out, the structure of the limbs and feet in this sub- order is as in the order generally, and the scapula has the same form in general. The symphysis mandibuli is furnished with teeth, and forms a long solid spout. The astragalus has a very peculiar form, being even Fig. 21. Skull of t'ori/j)/iorfo« eh-phantojiun, displaying braiu-ca'^ity, g nat. size. more exceptional than in Uintatheriiim. The superior articular surface is flat or concave in the middle. It is turned inward in front of the articular face for the inner malleolus, terminating in a long point. The cuboid ax-ticular face is quite small and sublateral, and sessile like the navicular. * Jour. Acad. Nat. Sci. 1874, March, "On Homologies of Molar Teeth of Mammalia Edncabilia", p. 20. PANTODONTA. 515 The fibular facet is vertical and is extensive, and the internal lateral is well marked. On the other hand the coracoid process is produced into a curved hook, and is thus more largely developed than in the Frohoscidians or PerissodacUjles. The neck is longer than in the Dinocerata. But one family of this suborder is yet known, the Coryphodontidai. Its characters and those of the genus Corypliodon were fully described by mj^self in the final report of the United States Explorations and Surveys West of the One hundredth Meridian, by Captain Wheeler, iv, pt. ii, p. 187-206, and to this work I refer for full details History. — The first piece recognized as belonging to a distinct genus, under the name of Corypliodon, was described by Professor Owen in 1846. This was a fragment of the mandible, supporting the last inferior molar. In describing it, Owen noticed the peculiar form of the posterior part of the ramus. He also referred to some superior molars, one of which is figured by Cuvier (Ossemens Fossiles, pi. 77, fig. G) as probably belonging to the same genus. These were alluded to by the French anato- mist as the Lophiodon de Soissons and the Lophiodon de Lyonnais. Owen named the species observed by him Corypliodon eoccmus, and it is believed that the teeth described by Cuvier belong to another species, to which De Blainville gave the name Corypliodon anthracoideus. Little, however, was known of this form until ten years later, when Pro- fessor Hebert, of Paris, obtained some addi- tional material from Meudon near Paris, and other localities. In the Annales des Sciences Nature lies for 1856, he gave a full account of the characters of the dentition, and described the femur. He explained correctly the homologies of the dental structure, and added a species, C. oiveni, which is of smaller size than the C. eoccentis. The first American species was made known by the writer in Feb- FiG. '2'2. Eight posterior foot of a species of Coryphodou lialf natural size. From Report Expl. W. of lUOtli Meridiau, Wheeler, iv, pt. ii. 516 THE WASATCH AND BRIDGER FAUN^. ruaiy, 1872, under the name oi Bathnodon radians, and the description wa& at that time confined to the superior molars, the femur, and the humerus. In February, 1873, in "The Short-footed Ungukta of the Eocene of Wyoming", I described the characters of the scapuhx and astragahis and its connections, which furnished reasons for removing the genus from the Perissodadyla and placing it in the Proioscidia, under a subordinal division, which was named the Fantodonta. The same course Avas pursued in the Annual Report of the United States Geological Survey of the Territories for 1872 (1873), where a second American species, B. latipes, was added. The next additions to our knowledge of the osteology of Cori/phodon are due to the exploration of the Eocene beds of New Mexico, conducted by the writer, in 1874, in connection with the United States Geographical Surveys West of the 100th Meridian. On November 28, 1874, in extracts from the Report of the Chief of Engineers, published in advance, I gave the general characters of the skull, and of the hind foot, determining the number of toes in the latter. The temporary dentition and three new species were also described. In some remarks before the Academy of Natural Sciences of Philadelphia, made March 9, 1875, I pointed out the near relation of these animals to the species of Corypliodon. In flae "Sys- tematic Catalogue of Vertebrata of the Eocene of Wyoming", April, 1875, the structure of the fore foot, including the number of digits, was pointed out, and the group Fantodonta removed, with the Dinocerata, to a new order, the Ambli/poda ; Corypliodon was referred to the Fantodonta, and two species were added. I announced the generic identity of the American and European forms in a communication before the Academy of Philadelphia, made April, 1876 (published April 26), pointing out the subordinate char- acters of the respective types.* My final report to Captain Wheeler, United States Army (1877), completed the description of the osteology, so far as accessible to me; and I may add that this is so far complete that there only remain unknown the number of the ribs and dorsal and lumbar vertebrte, and the structure of the hyoid apparatus. Genera. — There are five genera of Coryphodontidce: Corypliodon, Bath- * A short time after this, Prof. O. C. Marsh asserted the identity of Corijphodon and Bathmodon in the Amer. Joum. Sci. and Arts. PANTODONTA. 517 modon, Edacodon, Manteodon, cand Metalojjhodon. The last is easily distin- guished from the first by its dental characters, but Bathmodon rests on a pe- culiar foot structure, and its dental characters are unknown. As the feet of Metalophodon are not known, it is possible that it is identical with Bath- modon. Several species also have been referred to Coryphodon, of which the foot structure has not been ascertained, so that it is possible that some of them are Bathmodontes. The solution of these questions will depend on future discoveries ; meanwhile I leave most of the species in Coryphodon. In determining the last-named genus I have had the advantage of access to the specimens contained in the Museums of London and Paris, a privi- lege which I owe to Professors Owen, Gervais, and Hubert. To the last- named gentleman I am under especial obligations, as the specimens of Cory- phodon eoccenus contained in the Museum of the Sorbonne are much the most perfect in Europe. I give the characters of the genera below : I. Last superior molar with two interior cusps. All the superior molars with a well-marked external posterior V Manteodon. II. Last superior molar with but one inner cusp or angle. a. Last superior molar with posterior external cusp. Anterior two molars with posterior external V Ectacodon, aa. Last superior molar without external jjosterior cusp, t Anterior two molars with posterior external V. Astragalus transverse, with internal hook Coryphodon. Astragalus subquadrate, without internal hook Bathmodon, ft First superior molar only, with posterior external V Metalophodon. MANTEODON Cope. Proceed. Amer. Pbiloso. Soc. 1881, Feb., 1882, p. 166. American Naturalist, 1882, p. 73 (Dec. 30, 1881). The generic characters have been already pointed out in the key above given. They are a little more like those of the superior molar teeth of such Perissodadyla as Limnohyus and near allies, than those seen in the typical Cpiyphodon. The posterior transverse crest of that genus is here repre- sented by a complete V, but the anterior lobe of that crest which repre- sents the anterior V of the Perissodactyle is only a lobe, as in Gorypliodon. The tooth in fact is much like the penultimate molar of the latter genus. 518 THE WASATCH EPOCH. The two internal cusps are unique in the family The additional one is a growth of the inner extremity of the posterior cingulum, and is separated from the anterior inner cusp by a deep and wide notch. It is opposite to the posterior V, as the anterior inner cusp is opposite the anterior rudi- mental V. The premolar and incisor teeth are similar to those of Corypho- don. The skeleton is unknown. Manteodon subqdadratus Cope. Loci supra citati. Plate XLIVo; figs. 1-5. The characters of this pantodont are learned from a series of teeth which were found together by Mr. Wortman free from admixture of others. They are not worn, excepting by moderate use by the animal when living. The last superior molar is not of the oval form belonging to the species of Corypliodofi^ but is quadrate, with the internal side shorter, and with rounded lateral angles. The first anterior cingulum, which represents the anterior basal cingulum of the Lophiodontidce, is as elevated as in the species of Coryphodon. Externally it rises in a protuberance with sharp edge, which curves posteriorly and disappears on the external side of the crown. The inner extremity terminates abruptly, forming the anterior interior tubercle. The anterior external lobe is rather flat, and is not conical nor elevated above the anterior cingular lobe. It is not deeply separated from the latter, nor from the posterior V ; its edge is rough. The posterior V projects well inwards, and is rather narrow. Its posterior border extends as far out- wards as the point of junction of its anterior border with the anterior external lobe, and terminates in a slight elevation of its border. The base of the crown extends external to the base of the V, and forms a strong posterior external protuberance. This causes the outline of the external base to be concave. This side of the crown has several small protuber- ances and rugosities. The posterior basal cingulum extends as far exter- nally as the posterior V, and -terminates internally in tlie posterior internal cusp. The second or basal anterior cingulum is well developed. There are PANTODONTA. 519 no external nor internal cingula. The surface of the enamel is strongly and closely rugose where not worn. The posterior inferior molar exhibits a transverse posterior crest, with- out any tubercle or ridge in the mouth of the posterior V-shaped valley. There is a strong posterior cingulum, amounting to a narrow heel. As in the case of the superior molar, the enamel where not worn is closely and strongly wrinkled. The first superior premolar is characterized by the vexy small development of its internal lobe, which is only a strong basal cingu- lum. The crown proper has a sub-triangular outline, and the external face is flat and not concave. No external cingulum; enamel wrinkled. An external incisor has a large transversely extended crown, without cingula. A low rib on the median line of the inner side. Enamel wrinkled. In this and in another incisor the base of the crown is considerably expanded laterally. Measurements. M. I anteroposterior 035 Diameters of crown M. iii, sup. < transverse 041 ( vertical : 020 Width of M. iii inferior, posteriorly 022 Diameters of Pm.i, sup. 5 '*"*^'^°P"^*«"°'"- — "^^ ( transverse 014 Diameter base crown I, ii 024 Length crown i, ii 019 Width base crown i, iii 026 The crowns of the molars of this species are about as large as those of an ox. From the basin of the Big Horn, Northern Wyoming. ECTACODON Cope. American Naturalist, 1882, 73 (Dee. 30, 1881). Proceed. Amer. Philos. Soc, 1881, Dec, p. 167, Feb. 1882. In Ectacodon the last superior molar has more of the elements of a posterior external V than in Coryphodon, but not so much as in Manteodon. The posterior transverse crest, it is true, has no oblique posterior ridge joining it, to form with it more or less of a V. But the external posterior angle of the crown supports a cusp homologous with the vertical rib found at the basal or external angles of the Vs in Palceosyops and allied genera, 520 THE WASATCH EPOCH. and indicating the outlines of a V which lacks its posterior side, in a man- ner not seen in Coryphodon. The penultimate and ante-penultimate supe- rior molars are like those of the latter genus. Skeleton unknown. I have a single species of this genus. ECTACODON CINCTUS Cope. Paleontological Bulletin, No. 34, p. 1G7, Feb. 20, 1882. Proceed. Amer. Philo. Soc, 1881, Dec., pi. 167 (1882). PlateXLIVa; fig. 6. Six superior molars of one skull represent this species. They belong to a large animal, one about the size of the Manteodon suhquadratus. The last superior molar has a characteristic outline. It is not oval as in the species of Corypliodon, nor quadrate as in Manteodon sp., but sub-parallelo- grammic. The transverse diameter exceeds the anteroposterior, and the anterior and posterior sides are pai-allel. The external outline is slightly oblique and slightly notched in the middle. The internal border is regu- larly rounded. The basal or second cingulum extends entirely round the tooth from the posterior external cusp, round the inner base to the anterior external base of the crown, being absent only from the external base. The first cingula, both anterior and posterior, are well developed, as in the species of Coryphodon, and unite in the prominent internal angle. The posterior first cingulum joins the posterior basal cingulum at the middle of its length. The anterior first cingulum extends to the anterior external part of the crown, and then turns downwards and posteriorly, and termi- nates at the middle of the external base. The posterior crest is not trans- verse, but quite oblique, sloping at an angle of 45° with the axis of the jaw. The part of the crest which represents the posterior V is a good deal larger than the part representing the anterior V, and is closely joined with it. The latter is well separated from the anterior first cingular ridge and its anterior exterior elevated portion. The enamel of this tooth is finely wrinkled, and is more readily worn smooth than in the Manteodon suh- quadratus. The penultimate superior molar has the posterior V well developed, and its posterior basal or external angle is marked by a tubercle homol- ogous with that which is so prominent on the last molar. The anterior V 5:<^":x PANTODONTA. 52A-SV is a conic tubercle closely joined Avith the posterior V, and well separated from the anterior first cingular lobe. The basal cingula are well devel- oped, but do not meet on the inner base of the crown. The first or supe- rior cingula meet as usual in an interior angle, but there is a contraction of the anterior crest just before reaching this angle. The first true molar is smaller than the second and has the same general structure. Here, how- ever, the anterior first cingulum is more prominent near the internal angle than the posterior. The charactei's of the premolars do not differ from the corresponding ones of species of Corypliodon. The enamel is delicately wrinkled. The first superior premolar is not preserved. Measurements. M. I anteroposterior 034 Diameters of crowu of M. iii < transverse 043 ( vertical 015 I anteroposterior 028 Diameters M. i < transverse 033 ( vertical. 012 Diameters Pm. iii ^ »°*'"^°P''«t''"'^^ ^ ( transverse 030 It is probable that this species was about the size of an ox. CORYPHODON Owen. History British Fossil Mammals, 184C, p. 299, tig. 103, 104. Brou Lethiea Geognostica, 1856, p. 842. Hubert, Auuales des Sciences Naturalles, 1856, p. 87. Cope, Synopsis Extinct Vertebrata Eocene of New Mexico, 1875, p. 28. Marsh Amer. Journ. Sei., 1877, 81. Cope, Report U. S. Geol. and Geog. Expl. Survs. W. 100th Meridian, iv, pt. ii, p. 187, part 1877. Proceed. Aiuer. Philos. Soc, 1881, p. 166. Dental formula: I. -; C. ; P-m. -; 3 1 4 M. -. Canines large, no diastema. 3 Superior j)remolars different from the molars, consisting of an external and an internal V, the external the larger. The first and second superior true molars have two external Vs, the posterior well developed, and the anterior represented by a subconic cusp; a single internal cusp with V-shaped section, the anterior branch extending as a high transverse crest to the external border of the crown, forming the anterior triturating surface. The third true molar differs from the others in having the external Vs united into a crest, which is placed transversely, forming the posterior 522 THE WASATCH AND BEIDGER FAUN^. border of the crown. The inferior premolars differ from the true molars. Their crowns form a V, with the apex outward, and a short heel behind it with a more or less median keel, and increasing- in transverse width in the Fig. 23. — Protile view of skull of Coryphodon clephaniopus, from New Mexico, 5th nat. size. From Report' of Lieut. G. M. Wheeler to Chief of Engineers, 187.5, \t\. v. posterior teeth. The true molars support two transverse crests, each of which may send obliquely inward from its external extremity a low ridge. The anterior of these ridges is the best developed, and is always present. Fig. 24.— Superior surface of skull of Cnryphoihrn eJepTiantopus, above figured, §th uat. size. From final report of Lieut. G. M. Wheeler, vol. iv, pt. ii, 1877. Frontal and parietal regions flat, bounded by separated temporal ridges. Feet short, plantigrade. Digits 5-5, with short, wide ungues. Neck and tail of medium length. More or less perfect specimens of one hundred and fifty individuals of CORYPHODON. 523 the Coryphodontidce were obtained during my exploration in Northwestern New Mexico, under the organization of the survey of Capt. Gr. M. Wheeler. Portions of many others have since been obtained by Mr. Wortman and myself in Wyoming. Those specimens which include astragali are mostly referable to this genus, but a few from both regions belong to Bath- modon. It has, however, generally happened that specimens which include Fig. 25. — Skull of Coryphodon eUpliunlopus, from below, jtli natural size. From Report Expl. Surv. West of 100th Mer., G. M. Wheeler, vol. iv. teeth do not possess astragali, and vice versa, so that I have been compelled to disregard the generic position of the species for the time being, and have relied chiefly on the mandibular teeth for the characters, owing to the more irregular occurence of other elements; and the tubercles of the teeth are not always constant. The following key expresses the relations of these forms, most of which, perhaps all, are good species: I. The last inferior molar with three posterior cusps, the internal sometimes represented by a ridge ; or the posterior inferior molars with an accessory cusp or tubercle on the inner side between the crests (Coryphodon, Owen) : An internal tubercle ; last upper molar with an anterior cross crest and anterior external crest closely connected ; size largest C. anax. An internal conic cusp ; posterior crest oblique ; heel very small ; size medium C. cuspidatua. An internal crest ; posterior crest oblique; heel small; size medium C obliquiw. An internal tubercle ; posterior crest little oblique ; heel large; size large 0. lobatM. II. Posterior inferior molars without internal accessory tubercle. a. Posterior inferior molars with small or no heel : Large ; posterior superior molar oval, with distinct straight posterior crest ; inferior molars elongate ; symphysis mandibuli produced and narrower ; premaxillary elongate C. latipes. Medium ; inferior molars nearly as wide as long ; premaxillary short C. Jatidena. aa. Posterior inferior molars with prominent or wide heel : Medium ; posterior superior molar with posterior angle, and angulate posterior crest ; inferior molars elongate; symphysis mandibuli broad and short; premaxillary elongate ; tusk trihedral C. elephantopiu. 524 THE WASATCH AND BRIDGER FAUN^. Smaller ; premaxillary bone short ; tusk trihedral C. aimut. JMedium; premaxillary elongate; tusk comi)ressed and grooved C. moleatua. Large; last superior molar oval, with augulate posterior crest; its anterior lobe connected with ante- rior cingular crest C. repandus. III. Last inferior molar with but one posterior cusp from which a curved crest extends round the posterior border of the crowu. ■Superior true molars narrow ; external incisors sharply angulate on external face C. curvicristis. IV. Posterior inferior molar unknown. Posterior superior molar oval; posterior crest straight; internal crest fissured (? normally) ; a complete internal cingulum C. marginatiis. The C. eoccemis Owen, belongs to Section I, and the C. anthracoideus El v., and C. oivenii H^b., from France, belong to Section 11. Professor Marsh has published a figure of the skull of Coryphodon (Amer. Journ. Sci., 1877, PI. iv, fig. 1), which represents the temporal ridges as converging towards a sagittal crest. This is not found in the C. eoccemis, nor in any of the Ameiican species whose crania are known to me (C eUphantopiis, C. molestus). The first known American specimens of the family were discovered "by Dr. Hayden, on Bear River, near Evanston, Wyoming. They repre- sented two species, Bathmodon radians and Corypliodon latipes. I subse- quently visited the same locality and obtained numerous specimens, which further demonstrate the fact that two species were entombed there, and indicate that a third species was associated with them. The C. cuspidatus has been obtained in New Mexico and Wyoming; and the C. obliquus, C. lobatus, C. latidens, C. elephantoptis, C. simns, and C. molestus have only been found in New Mexico. Restoration. — The general appearance of the Coryphodons, as deter- mined by the skeleton, probably resembled the Bears more than any living animals, with the important exception that in their feet they were much like the Elephants. To the general proportions of the Bears must be added a tail of medium length. Whether they were covered with hair or not is, of course, uncertain; of their nearest living allies, the Elephants, some were hairy, and others naked. The top of the head was doubtless naked posteriorly, and in old animals may have been only covered by a thin epidermis, as in the Crocodiles, thus presenting a rough, impenetrable front to antagonists. The movements of the Coryphodons, doubtless, resembled those of the Elephant, in its shuffling and ambling gait, and may have been even more CORYPHODON. 525 awkward, from the inflexibility of the aukle. But, in compensation for the probable lack of speed, these animals Avere most formidably armed with tusks. These weapons, particularly those of the upper jaw, are more robust than those of the Carnivora, and generally more elongate, and attrition pre- served rather than diminished their acuteness. The size of the species varied from that of a Tapir to that of an Ox. There is no evidence that these animals possessed a proboscis, as was probably the case with some of the Dlnocerata. We must suppose that the Coryphodons were vegetable feeders, but not restricted to any particular class of food. They were doubtless, to a large extent, like the hogs, omnivorous. Position. — The genus Corypliodon is characteristic of the Lower Eocene formation in North America and Europe. In the former country it is con- fined to the Wasatch and Wind River epochs; in Europe, to the Suessonian and, perhaps, the Thanetiau of France and England. It is absent from the Upper Eocene of both countries. CORYPHODON CUSPIDATUS CopC. Report U. S. Geol. Survs. "W. of 100th Meridian, iv, i)t. ii, p. 206, pi. xlvi, fig. 1. This species is well characterized by the strong additional cusp found on the inner side of the crown of the last inferior molar between the interior extremities of the transverse crests. To give it more place, the posterior crest is more oblique than in other species. The accessoiy cusp is repre- sented by a crest in the C. eoccenus, and the New Mexican C. ohliquus. The typical specimen, including only a fractured last molar with a supporting fragment of the jaw, was found by myself in New Mexico. A second specimen was found by my assistant, Mr. J. L. Wortman, in the bad lands of the Big Horn Valley, Wyoming. It includes, however, only some jaw fragments with three inferior premolars, and two entire and two broken inferior true molars. These indicate a species of smaller size than the Batlmiodon radians, and agree with the typical specimen above men- tioned The molars preserved, excepting the posterior, do not differ mate- rially from those of other species, excepting the O. latidens, which is peculiar. M. .020 .017 526 THE WASATCH AND BRIDGEE FAUN^. Measurements. Dunensions of inferior Pm. IV ^^"'""P"^'^"^"^ c transverse t anteroposterior 025 Dimensions of inferior M. H^ jjjjj^g^,gj.gg „._,(, Width of crown of inferior M. Ill, beliind 023 Widtli of crown at crest 019 Width of crown at tubercle 024 CORYPHODON LATIPES Cope. Bathmodon latipes Cope, Annual Report U. S. Geol. Surv. Terrs., F. V. Hayden, 1872 (1873), p. 583. Proceed. Amer. Philos. Soc, 1873, p. 70. PI. xxix6, figs. 4-5; xlviii, figs. 7-14. The remains of Coryphodontidce obtained by Dr. Hayden, near Evans- ton, Wyoming, in 1871, included parts of two distinct species, a large and a small, which I described as Bathmodon radians and Cort/phodon latipes, respectively. The bones were mixed together when they came into my possession, but in most instances it is not difficult to distinguish them. An expedition which I made to the same locality, in 1873, enabled me to procure many additional bones of both species, and to confirm the distinc- tions already observed. It remains, however, difficult to assign a few of the bones to their proper species, and an astragalus indicates the possible existence of a third one. The smaller specimens obtained by Dr. Hayden, include atlas, axis, dor- sal and lumbar vertebrae, scapula, humerus, phalange, femur, astragali, &c. The transverse process of the atlas is stouter and less flattened at the base than in B. radians. The axis is but little oblique, and has a low, obtuse hypapophysis below. Its form is much as in the larger species, being rather elongate, but shorter than in Bhinocerus and other Perisso- dactyles. The dorsals and liimbars are short and plane; the former are obtusely, the latter acutely, keeled below. The glenoid portion of the scapula differs notably from that of the B. radians. Besides being smaller, it is narrower, its outline contracting regularly from the posterior border to the coracoid process, instead of curving outward to it as in B. radians. The external face at the base of the coracoid is nearly plane in C. laiipes, but is strongly concave in B. radians. The astragalus is considerably broader than long, the apex turned outward in front of the inner malleolus, being especially produced. The CORYPHODON. 527 tibial face is concave transversely, convex anteroposteriorly at the front, and plane behind. There is a posterior submarginal foramen, which is not bridged over in one specimen, producing a deep notch. The navicular facet has considerable transverse extent, and the anterior side of the bone is more transverse than in B. radians. The calcaneal facets are diagonally 02Dposite to each other; the outer is subround, the inner anterior narrow and transverse. It differs in the two specimens, the perfoi'ating foramen not being bridged over in the one (the type) with the similar posterior interruption described above. This may be due to fracture. The only ungual phalange has the articular face not quite sessile on the transverse rugose free extremity. Measurements. M. Diameter of diapopliysis atlas (fore and aft) 0. 036 Diameter of axial facet of atlas 034 ( fore ami aft ' 040 Diameter of cciitrum of dorsal < vertical (total) 043 ' transverse 059 Diameter of neural arcli of same < „.„ ( transverse 0j2 I anteroposterior 041 Diameter of centrum of lumbar< vertical (total) 050 V transverse 063 Diameter of head of femur 060 Length of astragalus fore and aft 050 Width of astragalus 065 Length of navicular facet 049 Width of navicular facet 020 W idth of cuboid facet 018 Length of cuboid facet 016 Width (fore aud aft) of anterior Calcaneal facet 018 Length of posterior calcaneal facet 022 Length of fibular facet (axial) 041 Length of terminal phalange 012 Width of terminal i)halange, proximally 015 Width distally .030 transverse 054 anteroposterior 080 Diameter of glenoid cavity of scapula ; The specimens procured by myself were taken from the bone bed on October 5 and 6, 1873. Those taken on the former day are of a ferrugi- nous color, and include right scapula, ulna and radius, sacrum, right ilium, and left femur. Those obtained oJi the following day are of a black color, and include left humerus, left tibia without distal extremity, patella, and right femur. With each lot is a cervical vertebra, but I am not sure 528 THE WASATCH AND BEIDGER FAUN^, whether these belong to this species or to the B. radians. These bones, or at least the femora, represent two individuals. On October 8, I obtained part of another scapula of this species. I did not procure any astragalus. Their uniformly inferior size distinguishes these bones from those of the B. radians, which I procured at the same place on October 5. The difference in the form of the glenoid extremity of the scapula, pointed out above, is maintained by these specimens. The important peculiarity in the form of the proximal extremity of the humerus remains to be noticed. In the B. radians, obtained by Dr. Hayden and myself, the greater tuber- osity is hugely developed, its proximal extremity forming a subhorizontal table nearly as wide as the articular head of the humerus at its middle. The surfaces of the head and tuberosity are separated by a low curved crest which descends to the external border of the bicipital groove. In the C. latipes the great tuberosity, though large, is not nearly so wide proxi- raally, its transverse diameter being scarcely half that of the articular face, on a transverse line passing just posterior to the bicipital groove. This difference is partly due to a more external position of the ridge separating the articular from the rough surfaces. The teres and pectoralis facets are large and impressed in the C. latipes; the latter being bounded below by a sudden retreat of the surface. The lesser tuberosity is not large, and con- sists of the anterior prominence of the inferior border of the pectoralis facet. The deltoid ridge is not distinct proximally, but becomes very prominent below the middle of the shaft, where it is twisted forwards as it descends. It is more prominent than in the humerus I figured in Captain Wheeler's report, PI. LXII, fig. 1, from New Mexico. The internal epi- condyle is prominent, while the external is wanting. The external twisted marginal crest is prominent and soon descends into the shaft. Measurements of humerus. M. Total length 323 . , . (transverse in one line J «fg'"'==^**^^t"^"°'*"y ^^'^ Proximal diameters ^ (of articular surface 067 ( anteroposterior r*=^«'^'^*'i'^"°^'ty ^^^ ( at bicipital notch 075 ( transverse P°*'^^ ■ ^-^ Distal diameters) \ of condyles at middle 071 ( anteroposterior external condyle 058 COEYPHODON. 529 The spine of the scapula is very prominent, and its fi'ee edge is wide, so, that both its anterior and posterior faces are concave. The interior face of the scapuhi is concave or curved backwards. Measurements of scapula. M. „ . ,, .. T , ..,, ( with coracoid 084 Proximal loneitudmal width < „ , . , .^ „„, ° (of glenoid cavity 063 Proximal transverse width 056 The radius is a robust bone with large extremities, of which the distal is the larger. The carpal articular surface is, however, smaller than the humeral, the greater width being caused by the large external tuberosity. The head is a transverse oval, as in the New Mexican species. The shaft is oval in section, and is flattened in the plane of the distal extremity except close to the head, where it rises a little inwards. Measurements of radius. Length 220 _. , „, .(transverse 068 Diameters of head < ,. , _,„ i vertical 043 Width of carpal articular face 044 The sacrum includes four vertebrae, and as the last one is broken, the presence of a fifth cannot be asserted. The intervertebral sutures are visi- ble. The centra and neural arches are depressed; the distal ones very flat. The neural spines are represented by a low keel. The transverse processes are expanded, and are thoroughly coossified distally, inclosing large inter- vertebral foramina, the anterior being the largest. Measurements of sacrum. Length of fragment 165 Width at first intervertebral foramen 168 Anteroposterior diameter of intervertebral foramina < . " (third 018 ( vertical 03^ Diameters of first sacral centrum < ' , ( transverse 058 The femur is but little shorter than that of B. radians, but is more slender in all its parts, notably in the condyles. The fossa ligamenti teris is well developed, and the head is more prominent than the great trochan- ter. The little trochanter has considerable longitudinal extent, and the 34 0 530 THE WASATCH AND BKIDGER FAUN^. third trochanter is only moderately pi'ominent. It is situated at the mid- dle of the shaft. The posterior face of the shaft is everywhere flat. The patella is an elongate oval and has not the tendinous prolongation of the one figured in Wheeler's report IV, PI. LVIII, fig. 4. Measurements of femur. M. Total length 376 Proximal width 109 Transverse diameter of head 056 Ti'ansverse diameter of great trochanter 053 Width of shaft at little trochanter 080 Width of shaft at third trochanter 066 Width of shaft below third trochanter 055 Kstal diameters^ *™°«^'^^^'''^^1''" f~ ( anteroposterior at external trochlear ridge 083 The tibia is characterized by the remarkable slenderness of its shaft as compared with the diameters of its head. Above and at the middle the shaft is compressed, so that its long axis is nearly anteroposterior. The crest is truncate by the wide insertion of the quadriceps extensor muscle, and incloses scarcely any fossa on the external face of the bone. The cotyli are separated by a wide open emargination behind, and a narrow groove in the position of the spine. The interior is one-fourth wider autero- posteriorly than the external. 3Ieasurements. M. „ • 1 J- i r *i ■ (transverse 095 Proximal diameter oi tibia ! c anteroposterior 070 T^. . /.. ii.-i( transverse 047 Diameters of external cotylus < C anteroposterior 051 Diameters of shaft at middle I t™"^^'^'"^'' °'^f ( anteroposterior 0 6 The teeth discovered with these specimens are superior molars, pre- molars, incisors, and canines. No inferior true molars were obtained, so that the relationships of the C. latipes to the species discovered in New Mexico remains uncertain When the characteristic teeth are obtained, it may be found to be identical with some of the latter. I look for future investigations in Wyoming, now under way, to decide this question. From the Wasatch beds on Bear River, near Evanston, Wyoming. CORYPHODOK 531 I refer seven individuals from the Big-Horn Wasatch Basin provision- ally to this species. Three of these are represented only by superior teeth, &c., and in four the last inferior molar is preserved. Of the latter, three have an angle, sometimes almost a crest, descending from the posterior inner tubercle, as in C. obliquus, but the specimens are all of superior size to that species, some of them very much exceeding it. It is also possible that this i-idge is not a constant character. This species has the dentition which I have referred to the Bathmodon radians, but no astragalus of that species occurs in the Big-Horn collection. I refer it to the C. latipes, although the teeth of the typical specimen have not yet been identified. I hope soon to be able to decide this question. CORTPHODON ELEPHANTOPUS Cope. Report of Vert. Fobs. New Mexico, U. S. Geogr. Surveys W. of 100th Mer., 1874, p. 10. Id. Annual Rep. U. S. Geol. Snrv. W. of 100th Mer., 1875, p. 95, plates v, vi. Report do. iv, pt. ii, 1877, p. 217. Plates L-LIV. Plate XXIX e. Portions of the dentition of both jaws, including the last molar teeth of two individuals, prove that this species inhabited Wyoming in the early Eocene period. One of the individuals, represented only by the last molars of both jaws, is a little smaller than the typical specimen of which an entire cranium is figured in Captain Wheeler's report (4to, 1877, PI. LI- III), while a second specimen, which includes the entire superior molar series, is a little larger than the same. This species is characterized by the obliquity of the edge of the poste- rior crest of the posterior superior molar backwards away from a transverse line ; and by the slope of the external side of this crest. In other words, the inner half of the posterior crest nearly forms a V, like that of the penul- timate molar. The posterior edge of the V is present, running outwards from the inner end of the posterior crest, which thus becomes the apex of the V. The C. elephantopus thus most nearly approaches the genus Man- teodon of all the species. To accommodate the obliquity of the crest the posterior outline of the last upper molar is strongly angulate, giving a sub- triangular outline. The heel of the last inferior molar is insignificant 532 THE WASATCH FAUNA. Specimens were collected by J. L. Wortman in the Big-Horn region, Wyoming. CORYPHODON SIMUS CopC. Report Vert. Foss. New Mexico, U. S. Geogr. Surveys W. of 100th Mer., 1874, p. 8. Report U. S. Geogr. Surveys W. of lOOtli Mer., 1877, iv, pt. ii, p. 225. PI. LV. A broken mandible and maxillary bone, with several teeth, represent this small species in the Big-Horn collection. Maxillary teeth of similar proportions were found by Russell S. Hill in the Eocene of Powder River, Wyoming. CoRYPHODON REPANDUS Cope. Paleontological Bulletin No. 34, p. 171, Feb. — , 1882. Proceed. Amer. Philos. Soc, 1881, p. 171 (1882). Plate XLIVe; figs. 1-4. This large species is known from the posterior portions of the dentition of both jaws, with an entire symphysis. The last superior molars are intermediate in outline between the reg- ular oval of the C. latipes and the subtriangular form of the C. elepJiantopiis. The peculiarities of the species are seen in the posterior crest. The two lobes of which this is composed do not form a continuous line as in C. latipes and C. simm, but form an angle with each other as in C. anax. The anterior lobe is compressed, and its long axis is nearly that of the jaw; the second lobe leaves it at a right angle, but curves backwards as it extends inwards, giving a concave exteroposterior border. There is no ridge de- scending outwards from the inner extremity of the crest, to form a V, as in C. elephantopus. But the posterior basal cingulum extends to the external side of the tooth, which is not the case in any other species known to me excepting the C. marginatus. The anterior cusp is closely joined to the external elevation of the anterior first cingulum as in C. anax; a character which separates it from all other species. A strong trace of a cingulum passes round the inner base of the crown. No external cingulum. The first true molar does not diifer materially from that of other species. It is considerably smaller than the last. The apex of the premaxillary bone with the second incisor and alveolus of the first is preserved. The bone CORYPHODON. 533 is rather short. The crown of the incisor is regularly convex externally, and is not expanded at the base. There is a strong internal cingulum. A fragment of the lower jaw supports the last two molars. The internal angle of the last one is unfortunately broken. The postei'ior crest is, however, perfectly transverse, which is not the case with the species with three posterior tubercles. The preserved part of the posterior border shows a distinct, rather narrow heel. The anterior Vs are well developed, and there ai'e no lateral cingula. The symphysis is flattened out by pres- sure. The inferior canine is large. It is sub-triangular at base and has an anterior basal angular projection. Measurements. M. _. , „ ,,...( transverse 016 Diameters of sui^erior M. lu ^ ( longitudinal 067 _ . , J. • nT ■ ^ transverse 036 Diameters of superior M. 1 ^ , . ,. , .,. c longitudinal OSa T^. . „ ■ o< vertical 018 Diameters crown i. 2 < „, „ ( transverse 018 ( transverse 0^8 Diameters inferior M. iii < anteroposterior 040 ( vertical in front (restored) 024 Length of symphysis - 107 Depth of ramus at M. iii 056 The superior molars of this species might readily be taken for an un- dersized individual of C. anax, but the last inferior molar is of a different type, and refers the species to a different section of the genus. The Big-Horn Basin; J. L. "Wortman. CORYPHODON CUEVICRISTIS Cope. Paleontological Bulletin No. 34, p. 172, Feb., 1882. Proceed. Amer. Philos. Soc, 1881, Dec. 172, (1882). Plate XLIVc. The fragments which represent this species belong to one individual. They include a considerable part of both mandibular rami with numerous molar teeth, and most of the inferior incisors loose. Also the second supe- rior molar, some superior premolars, the canine, and three or four incisors, 534 THE WASATCH FAUNA. two of them in place in an incomplete premaxillaiy bone. None of the bones of the skeleton were obtained, so far as known. The ramus of the mandible is both robust and deep. Its inferior bor- der does not rise posteriorly so much as in some species, as e. g., C. latidens, and the ansrle is well below the horizontal line of the dental alveoli. The dental foramen is just about in this line. The inferior premolars and mo- lars do not differ from those of several other species, but tlie last molar has several peculiarities. The external cusp is the only one of the posterior pair which is present. It gives origin to two crests, both of them curved. The posterior represents the usual posterior transverse crest, but is gently convex backwards, and turns forwards on the inner side of the crown, only terminating at the external base of the anterior cross crest. The other curved crest is low, although higher than in most species, and extends to the middle of the base of the anterior cross crest. There is a distinct heel which is elevated at the middle and disappears gradually at each end, not being abruptly incurved as in C. anax. The anterior part of this tooth is as peculiar as the posterior. The external cusp gives origin to three crests, two of them the usual limbs of the anterior V ; while a third descends to the anterior border a little exterior to its middle. It incloses a deep groove with the anterior ridge of the anterior V. This arrangement is not seen in any other species. The inferior canine is robust, and has its anterior angle prominent, but not alate. The crowns of the inferior incisors are regularly convex exteri- orly, and have no cingula. They are regularly graded in dimensions. The superior molar preserved is probably the penultimate. Its ante- rior portion is broken. The posterior external V is narrower tlian usual for a second molar, and resembles somewhat that of the last superior molar of the Manteodon subquadratus. A slight contact face on the posterior cingu- lum shows that this tooth is not the last molar. The said cingulum extends to the external base of the V; in rising to the internal cusp it forms a sig- moid curve. The cingulum below this, on the inner base of the crown, is rudimental. The superior canine has a long and I'obust crown, with a trian- gular section to the apex. The posterior face is a little wider than the other COEYPHODON. 535 two, which are equal. Tlie anterior is sHghtly concave in cross-section, and the posterior slightly convex transversely, altliough concave longitu- dinally. There is a weak ridge nearly parallel to and near the postero- external angle, and traces of others on the postero-external face of the crown in front of this one. The antero-internal angle is swollen at the base. The superior incisors present characteristic features. The ridge of the external face, which is weakly developed in some of the species, and is wanting in others, is here represented by a strong longitudinal angle, which extends from the base of the crown to its apex, dividing the external face into two distinct planes. This character is most marked on the external incisor, where the planes are sub-equal, and concave. On the second the anterior plane is smaller, and on the first it is a good deal smaller. These incisors have a weak internal cingulum, but no external one. Measurements. M. Length of ramus from Pm. iv, inclusive „ 257 Lengtli of inferior true molars 098 Diameters of M.i inferior ^'^"t^™!"'^**^™'" ^^'^^ < transverse 020 T^. . e-Ki ■■■ ■ r ■ < anteroposterior 036 Diameters of M. Ill inferior^ ' „„ ( transverse 029 Depth of ramus at M. iii 075 _. . -,, .. . < anteroposterior 0315 Diameters of M. ii superior I ^ „„„ c transverse 039 I longitudinal 094 Diameters of crown of superior canine < anteroposterior 022 ( transverse 034 _. , , CI ••■(vertical 022 Diameters of crown ot I. lu •; ( transverse 024 The numerous characteristic marks show that this species is one of the most distinct of the genus. It is also one of the largest, being second only to the C. anax. From the Wasatch formation of the Big Horn ; J. L. Wortman. COEYPHODON MARGINATUS Cope. Paleontological Bulletin No. 34, p. 176, Feb., 1882. Proceed. Amer. Pliilos. Soc, 1881, Dec, p. 170, (1882.) Plate XLIVe; flg. 5. This is one of the smaller species, having nearly the dimensions of the 536 THE WASATCH FAUNA. C. molestus. It is only represented by the superior canine, first inferior pre- molar, and last superior molar of one individual found together by Mr. Wort- man. Their size, mineral condition, and degree of wear render it probable that all belong to one individual. The sviperior molar is of the oval type, without posterior shoulder. The posterior crest is therefore straight, and parallel with the anterior crest. Its inner extremity does not display the least tendency to form a V, as is seen in C. elephantopus. Its exterior extremity is widely separated from the external prominence of the anterior crest (cingulum). The latter displays, at its inner extremity, the peculiarity of a deep fissure of the anterior side, which nearly divides the crest, and partially isolates the internal tubercle. Adjacent to the fissure its crest is tuberculate. The posterior upper cingu- lum descends from the inner cusp to the basal cingulum. The basal cingu- lum is well developed on the anterior and interior sides of the crown, and on the posterior as far as the base of the inner cusp of the posterior crest, where it gradually fades out. Enamel wrinkled. The superior canine is remarkable for its small size. The posterior face is a little the widest, and its bounding edges are sharp, but not ex- panded. There are no prominent ridges of the enamel. The anterior face is moderately wide. The first inferior premolar presents no peculiarities. Measurements. M. ( anteroposterior 028 Diameters of M. iii 8uperior< transverse 038 ( vertical 019 Diameters of Pm.i inferior 5 ^'^t"°P°«**="''^--. ^J^ < transverse posterior UU9 DiametersofC. superior 5 '^"teroposterior.. 014 ( transverse posterior 018 The superior molar is but little worn, and shows that the animal was just adult. The canine is more worn than the molar. There are several characters which mark this species as distinct from those previously known. It is the only member of the genus which has a complete internal cingulum. The fissure of the anterior crest, if normal, is peculiar to this species. The superior canine is disproportionately small. Big-Horn "Wasatch, Northern Wyoming. COEYPHODON. 537 CORYPHODON ANAX Cope. Plate XLIVe, fig. 6; XLVIIIa. Mr. Wortman sends m^ a number of teeth of probably two individuals, wliicb exceed in size those of any species of Coryphodon yet known, and differ in certain details of form from all of them. The specimens consist of incisors, premolars, and molars of both jaws of One animal, and an inferior canine, which from its separate wrapping, I suppose to have been derived from a different locality. The incisors and premolars have the form usual in species of the genus, differing only in their large size. A well-preserved superior true molar is probably the third. It has the form usual in the genus, but exhibits two peculiarities. The posterior transverse crest is divided more deeply ^than usual by a deep notch which enters it from the transverse valley. The external portion is the shorter, and exhibits the peculiarity of being con- nected with the external part of the anterior transverse crest. It is as closely connected with this crest as it is with the internal portion of the posterior crest. The external connection does not exist in the other species of the genus, where the two crests are separated at their outer extremities by a deep valley. The posterior basal cingulum is obsolete, while the anterior is well developed. The enamel of this tooth, where not worn, is wrinkled. The posterior part of the last inferior molar is characteristic. The posterior transverse crest is short and very oblique, its inner extremity striking the posterior margin near the middle. Here it is elevated into a cusp, which rises above the surrounding parts in a characteristic manner. There is no ledge round its posterior base, but the border expands outwards at the base of the true crest. The additional inner marginal tubercle is low and compressed, as in C. lobatus. A second inferior true molar is nor- mal, with well -developed anterior marginal ridge. The inferior canine mentioned is of large proportions, exceeding by one-half, the dimensions of the inferior canine of C. lobatus. Its crown is curved outwai'ds, and has a basal alate expansion of its internal ridge. Measurements : Diameters of last superior molar, anteroposterior, .039 M. ; transverse, .051 M. Diameters of second inferior true molar, anteroposterior, .039 M.; transverse, .028 M. Length of inferior canine, .160 M. Length of crown of canine, .090 M. Diameters of base of crown of canine, ver- tical, .037 M.; transverse, .036 M. This species is nearest the C. lobatus in some respects. The short posterior crest of the last inferior molar, with its cusp-like extremity, and the absence of posterior ledge on this tooth, will readily distinguish it. 538 THE WASATCH FAUNA. Among the large Coryphodontes from the Big Horn Basin two sizes may be distinguished, a larger and a smaller. The latter usually have the posterior crest of the posterior inferior true molar transverse, and there is no interior crest or tubercle in front of it. Those I have referred to under the head of C. latipes, and the subject of Plate XLVI represents tliem, ex- cepting only the spaces between the premolar teeth. But some of them display a more or less distinct trace of the internal crest, and in one speci- men it is present on one side and not on the other. The larger specimens always possess the internal tubercle, and I refer these to the C. anax. The tubercle and posterior crest vary somewhat in proportions. In two speci- mens the latter is very short and oblique, its internal extremity having the position of the heel of a five-lobed molar; in three specimens it is longer and more normal. This is the character of the Conjpliodon Jobatus. In such specimens the internal lobe is nearer the extremity of the transverse iii'est, and the posterior border of the tooth is not angulate backwards. The specimens of this kind are as large as those typical of C. anax, and perhaps should be regarded as belonging to the C. lobatus. Owing to the want of superior molars, I cannot ascertain the full characters of the latter species. A partially complete skeleton of a true C. anax includes the following bones: most of the mandible with several, including the last, molars; a few vertebrae, including axis; glenoid cavity of scapula; humerus and ulnae ■complete, with parts of radius, parts of carpus; femur and tibia complete, parts of fibula, carpus and phalanges. The ramus of the lower jaw is considerably deeper than that of the C. latipes (cfr. PI. XLVI), and its inferior border rises backwards just below the posterior border of the last inferior molar. The symphysis extends to below the posterior border of the third inferior premolar, and the gutter for the tongue is quite deep. The surface spreads out to the bases of the ca- nines and incisors, losing its concavity at the median border. Tlie mental foramen is large and is situated below the first premolar on one side, and is double, and is below the second premolar on the other. The second true molar has the usual characteristic form of the genus, including a narrow posterior basal cingulum. Tlie last molar is like that of other species (ex- cepting the C. curvicristis) anteriorly, but the posterior crest forms a rect- COKYPHODON. 539 angle with the angle directed posteriorly. The distance from the lobe into which this angle rises to each of the intermediate tubercles is about equal. There is no heel, but a short, narrow, outward-looking cingulum extending from the external side of the posterior lobe, represents it. No other cingula; enamel finely wrinkled where not worn. A superior incisor has the crown little expanded laterally and quite thick anteroposteriorly. It has a well- marked obtuse external angle, and internal basal cingulum. The external faces are not flat or concave as in C. curvicristis. The superior canine has an immense root, and a three-sided crown. The external and posterior faces are gently convex in section, the former gently curved downwards, and neither have any ridges. Measurements of jaws. M. Depth of ramus raaudibuli at M. iii ^ 092 Length of bases of inferior true molars 100 Diameters of M.ii^^"t'^^''P°^*'^"°'' 0^2 ( transverse 024 Diameters of M. m ^ anteroposterior 043 transverse 0275 vertical 031 Diameters of base of crown of inferior canine ( transverse 027 Width between bases of canines 095 Width between bases of Pni. ii 044 Length of superior canine, apex supplied 214 Length of crown of canine, apex supplied 072 Transverse diameter of base of crown, apex supplied 033 The centrum of the axis is considerably wider than long, and is not keeled below. The dentate process has a round section. The superior or ligamentous facet is separated from the inferior or atlantal face by a groove all round. Three additional cervicals, a dorsal and a lumbar vertebrte, were found thirty feet down the ravine from the jaws and limb bones, ac- cording to Mr. Wortman. As no other vertebrae were found with the latter, and no other parts of a skeleton were associated with these vertebrae, all are viewed as pertaining to the same animal. They, however, lack epiphyses. As the last inferior molars, though fully protruded, are not worn on the posterior lobes, the association of these vertebrae is not impossible. The cervicals are quite short, and the centra are somewhat oblique, and the articular faces wider than deep. The posterior is deeper than the anterior. The inferior face is neither keeled nor strongly angular, and its posterior border is produced so as to overlap the succeeding centrum to its middle. 540 THE WASATCH FAUNA. The dorsal centra are short and contracted at the middle, and without keel or hypapophysis. The capitular fossae are strong on both faces of the bases of the diapophysis. The centrum of the lumbar is relatively a Httle longer, and has a median thickened ridge below. Measurements of veriebrce. ■' M. Length of axis with dentatus 105 T,. , „ , ■ S anteroposterior 65 Diameters of centrum axis < '■ ,„. { transverse lua ^. ^ ^ X • ^ r, •••(vertical 047 Diameters of anterior race C. iii ■! ( trans ve rse uvo ( vertical 035 Diameters of centrum dorsaU transverse 066 ' anteroposterior 053 Length of centrum lumbar 037 The glenoid cavity of the scapula is rather narrow, and its anterior region is narrowed even more than in the C. latipes, and is produced into an acute tuberosity. This is close to but distinct from the coroacoid, which is broken off from the specimen. The spine rises abruptly from a thick .base from near the edge of the glenoid. The proximal extremity of the humerus is a little crushed, but shows that the proximal extremity of the great trochanter is half as wide as the articular face measured on a trans- verse line. Its proportions are thus intermediate between those in the G. latipes and the Bathmodon radians (see page 276). The shape of the prox- imal extremity is subtriangular. The inferior portion of the deltoid crest is prominent, and twists inwards, continuing by an angular ridge to the internal edge of the condyle. The internal epicondyle is prominent, both outwards and backwards. The internal condyle is also prominent and twists back- wards in a crest which disappears on the inferior half of the posterior face of the shaft. The condyle is rather short; the inner flange is prominent, and the inner cylinder has its external part beveled quite steeply. The ole- cranar fossa is mostly external to the middle line. Measurements of scapula and humerus. M. _. , i I -J -i ( anteroposterior 105 Diameters at glenoid cavity < ' ( transverse 063 Width of neck of scapula 095 Uran8verse^^'*l^*'^^<^'^°«^*y l*^ Diameters of head of humerus.^ ( articular surface 093 ( anteroposterior Diameter shaft at middle 075 COEYPHODON. 541 f total transverse 128 (condyles transverse 082 anteroposterior 1 fl-g« «^2 < cylinder 058 When the olecranon is placed with its base on a level surface the radial facet of the ulna slopes inwards at an angle of 30°. It is nearly plane. The olecranon narrows to an apex by the gradual descent of the superior border, the steeper rise of the inferior surface, and the oblique truncation of the inner side. The shaft of the ulna is rather short, and is compressed, the long axis being directed downwards and inwards at an angle of 45°. Its inner side is divided equally by a low straight interosseous ridge, and is bordered below at the distal extremity by a horizontal projecting ridge, continuous with the inferior surface. The external face is plane, and the inferior edge nearly straight. The carpal face is compressed in the direc- tion of the shaft, and is directed obliquely inwards, coming from the distal extremity. A comparison of this ulna with that of a specimen here re- ferred to the C. latipes, shows that while the latter has nearly the same vertical diameters, it is considerably shorter both in the shaft and the olecranon. The head of the radius of the C. anax is transversel3' expanded, and the internal border is reflected posteriorly or proximally, and the external bor- der distally. There is a flat tuberosity on the external part of the superior border of the cup, and no notches anywhere. Measurements of ulna and radius. M. Length of ulna 350 Length of olecranon 075 Length of olecranon, plus glenoid 155 Depth of middle of olecranon 058 Depth at coronoid process 083 Depth at middle of shaft 050 Depth of carpal facet 046 i vertical 043 transverse 071 c Diameters of head of radius i I The pisiform bone is robust and is considerably expanded distally. The unciform has the usual form. The three inferior facets are distinct, and the inner one is very oblique, connecting by equal angles the median distal facet with that for the os magnum The posterior aspect presents a conical claw-like tuberosity. The lunar face is not separated from the cuneiform face by an angle. 542 THE WASATCH FAUKA. Measurements of carpus. Length of pisiform 054 Widtli of shaft 028 Width of distal extremity 048 ( •„ 11 ( fore and aft 032 V proximally < Diameters of unciform < I transverse 058 ( vertical anteriorly 028 A segment of the sternum is subquadi-ate and flat, as in the C. latidens, but thicker. The length is M. .058; width at middle, .044. The femur is rather elongate, with the shaft less robust than in the Bathnodon radians (see Plate XLVII). The head projects beyond the great trochanter, and has a deep fossa Ugamenti teris near the posterior border. The little trochanter is a prominent crest of two inches in length on the internal edge of the bone. The third trochanter is broken off. Its base is at the middle of the shaft. The rotular groove is rather wide, and the lat- eral borders are equal, and not much elongated. It extends well proximally. The epicondyles are insignificant; the external is impressed with three fos- sae, one on the edge of the condyle, and the middle one is the largest. The internal condyle has the widest sweep, and looks obliquely towards the external condyle. The inter-condylar fissure is rather narrow and deep. 3Ieasure7nents of femur. M. Length 477 Width proximally, with great trochanter 138 Transverse diameter of head 073 Width of shaft below third trochanter 064 Width at epicondyles 105 Anteroposterior diameter inner condyle 077 Anteroposterior diameter outer condyle 004 The tibia is much shorter than the femur, and is rather more slender than in some species of the genus. It presents the generic characters of flat crest and ungrooved distal articular face. The most slender part of the shaft is below the middle. The inner femoral cotylus has a consider- ably greater anteroposterior diameter, and there is a free edge behind it which increases the projection beyond external cotylus. There are var- ious longitudinal rugosities on the internal face of the proximal third of the bone, and the wide face of the crest is grooved striate. The malleolar process is not large, is acuminate, and turns backwards. The posterior border has an angle near the base of the malleolus, but there is no groove COEYPHODON. 543 for the flexor tendons of the foot and digits. The patella is flat, and does not exhibit the distal prolongation seen in some specimens; e. g., the one flgured in my report to Captain Wheeler, Vol. IV of his general report, Plate LVIII, fig. 4. The proximal end of the fibula is unusually large; it has a nearly quadrangular section, and the tibial facet covers about half the oblique proximal face. The calcaneum is quite robust. It presents the usual characters. The cuboid facet is small and more than usually oblique inwards. A tuberosity continues the inferior face between this facet and the base of the sustentaculum, and is separated from the former by a fossa. The sustentaculum is narrow, and its astragalar facet oblique downwards and forwards. The external astragalar facet is flat; external to it a large smooth surface receives the extremity of the fibula. Below this is a deep longitudinal fossa, and below this a strong horizontal crest, which extends to the cuboid facet distally and to the middle of the heel posteriorly. The posterior extremity of the calcaneum has a nearly quadrate outline. Measurements of posterior foot. m. Length of tibia on front to spine 300 Widtli of head 105 Anteroposterior diameter external cotylus 075 Anteroposterior diameter internal eotylus 053 Least diameter of shaft 042 Diameters distal end tibia < " ( transverse 084 Length of patella 094 Transverse width head of fibula 052 Length of calcaneum , 106 Width calcaneum at sustentaculum .081 Width calcaneum at free extremity 048 Depth calcaneum at free extremity 042 Depth calcaneum external facet 045 Depth calcaneum cuboid facet 029 Width of cuboid facet 037 Not having an astragalus or posterior foot of the C. anax, it is not yet possible for me to state whether this species is a Bathmodon or a true Cory- phodon. The large Bathmodon pacliypus is distinguished from the G. anax by various characters which are mentioned under the head of that species. The Coryphodon anax has been only found so far, in the Wasatch beds of the Big-Horn Basin of Wyoming. J. L. Wortman discovered it. It was originally described in the Paleontological Bulletin No. 34, p. 168, and is figured in the present work in Plates XLIVa, figs. 7-12; XLIV6; XLIVe, fig. 6; XLIV/ 544 THE WASATCH FAUNA. BATHMODON Cope. Proceed. Amer. Philos. Soc, 1872, p. 417, Feb. 16, 1872. Annual Report U. S. Geol. Surv. Terrs., F. V. Hayden, 1872, p. 586 (1873). Systematic Catalogue Vertebrata Eocene New Mexico, 1875, p. 24. American Naturalist, 1882, January, p. 73. Paleontological Bulletin No. 34, p. 165, Feb., 1882. This genus reposes as yet on the structure of the posterior foot, which is however not completely known. The astragalus is less transversely ex- tended than in Coryphodon, and the internal apex is recurved, and cames on its interior extremity an articular facet not found in that genus. It looks inwards, and stands below the middle of the inner side of the tibial face of the bone. It is not certain what element articulates with this facet. It may be a proximal extension of the proximal extremity of the entocunei- form. This is questionable in view of the square truncation of the facet and its entirely inward presentation. It may be a supernumerary bone forming a spur. So far as known the other characters of the genus are as in Corypho- don. The skull has not been found. Some bones found with the type specimen of B. radians have the following characters: Some anterior sternal segments are cylindric; in one, the articulations for the haemapophysis project laterally, giving the piece a T-shaped form. The atlas has a flat diaparapophysis, presenting its edges fore and aft; the arterial canal traverses it obliquely. The coracoid is double, having a tuberosity on the edge of the glenoid cavity, and a prominent hook just outside of it. The lumbar vertebrae are quite short. The cuneiform bone is narrow pyriform, with two triangular facets on one side, the smaller being sublateral, and one twisted over the other. The ungual phalanges are very short, somewhat flattened, and with the terminal portion transverse and rugose as in some toes of Elephas. Bathmodon radians Cope. Proceed. Amer. Philos. Soc, 1872, Feb. 16, pp. 417, 418. Hayden's Geol. Surv. of Montana, 1871, p. 350. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 587. Coryphodon radians Cope, Report U. S. Geol. and Geog. Expl. Surv. W. 100th Meridian, G. M. Wheeler, iv, part II, p. 206. t Bath- modon aemicinctus Cope, I. c, p. 418. U. S. Geol. Surv. Terrs., 1872, 1873, 588. Plates XLV, XL VI, XLVU, XL VIII; figs. 1-6. The original specimens on which this species was recorded, were obtained by Dr. Hayden near Evanston, Wyoming. They include parts BATHMODON. 545 •of two individuals represented by maxillary teeth, scapulae, humerus, femur, tibiae, fibulae, astragalus, and cuneiform bones. I subsequently obtained from the same person who exhumed these bones, both rami of tha lower jaw of probably one of these individual specimens. I visited the locality in 1873, and with many specimens of bones of Coryphodon latipes, I obtained a humerus and a femur, agreeing with those of the Bathmodon radians obtained by Dr. Hayden. This species is larger than the Corypliodon latipes, and is one of the largest species of the family known to me. It is distinguished from the 3atter not only by the form of the astragalus already mentioned, but by marked peculiarities in the scapula, humerus, and fibula. Those dis- tinguishing the first two bones, have been noted under the head of the C. ■latipes. The inferior premolars are all two-rooted, and form an uninterrupted series. The basis of the malar part of the zygomatic arch originates oppo- site the adjacent parts of the penultimate and last molars. The premaxil- lary bone is massive, and with but little area for attachment with its fellow in front. The incisor teeth are large, with subcylindric roots, and their alveoli are well separated. The crowns are expanded transversely, with convex cutting edge. The premaxillary bone is elongate, flat, and with a sloping superior face, which rises gently inwards. The bases of the incisors stand obliquely outwards. The inferior surface is flat, and the basis of the broken palatal ^pine is rather small. An incisor tooth has a transversely diamond-shaped crown, slightly twice concave on the inner faces, strongly convex on the outer, with a faint external cingulum near the external angles. Enamel obsoletely striate. A posterior superior premolar has a cingulum on the inner obtuse apex. The crest of the inner crescent, descending on each side of the apex of the outer, forms a cingulum-like ledge at its base as far as the angle formed by -the descent of the apex of the outer crescent. The outline of the crown of this tooth, viewed from above, is narrow cordate, with obtuse apex. The convexity of the outer crescent inwards is very strong, and the base -of the crown is externally two-lobed. Enamel striate rugose. In a more 35 0 546 THE WASATCH AND BEIDGEll FAUN^. anterior premolar (with three roots) there is no internal cinguhim, and the crest of the inner crescent is not carried to the external basis of the tooth, • and is entirely wanting on the posterior face of the tooth. The external crescent is more vertical and less concave. Outline of crown subtriangular. The transverse diameters of all the superior molars exceed their longi- tudinal. In the penultimate, which may serve as a type, this superior or outer plane of the inner crescent ridge extends along about .66 of the posterior of the outer crescent. In the last molar the surface is very wide on the posterior and inner side of the external crescent; it then contracts, and expands again on the posterior side, its outer bounding crest reaching to the external margin of the crown. Besides these points, the molars possess a strong cingulum along the posterior base of the ci'own, which unites with the surface near the inner protuberance of the latter in the penultimate; in the last molar it reappears, forming a short lobe on the posterior face. The enamel where not worn is slightly rugose. In the mandible the incisors radiate around the narrow extremity of the trough-like symph3'sis, and have transversely expanded crowns. The canine is inclined forwards, and forms part of the same series. Its crown is triangular in section, the outer face convex. In the males it was enor- mously enlarged, as indicated by a symphysis in my possession. The ante- rior premolar approached the canine. The premolars have an external chevron directed inward, whose exterosuperior surface of enamel is acute cordate. Besides this is a little longitudinal ridge, which represents another chevron of the true molars. On the first of the latter, both chevrons are developed, the posterior the least, both with their anterior ridge boundaries lowered; they sink entirely on the last two molars, which become thus two-crested, as in those of some Tapiroids, and the premolars of Binotherium. The last inferior molar has a narrow ledge in place of a heel, which sends a nan*ow ridge upwards and outwards. There is no trace of tubercle or crest in the interval between the external ends of the cross-crests. The oblique anterior connecting ridges are low in the inferior molars of this species. The first and second molars have posterior cingula relatively as BATHMODOK 547 large as that of the last molar. The premolars are separated by inter- spaces; a character I have not seen in any species of Corypliodon. The transverse process of the atlas is rounded distally, and is about as long as wide; the surface for the axis is directed obliquely inward. The apex of the scapula is a massive flattened acumination with trun- cate extremity. The spine is elevated and truncate next the glenoid cavity, which is a wide oval, much produced at the coracoid margin. In the humerus, the hook of the greater tuberosity is developed, but is not much elevated above the proximal plane. It originates from an external expansion of the greater tuberosity, which bears a shallow con- cavity separated from the head by a low curved subtransverse ridge. As pointed out under Coryphodon latipes, this expansion of the great tuberosity is very large, its width equaling that of the articular surface of the head. An almost perfect femur of B. radians is preserved. The third tro- chanter is not very prominent The little trochanter is little developed; the great trochanter is large but does not equal the head. The latter is subglobular, and the ligamentous fossa extends to its rim. The distal rotular surface is prominent, the inner edge more so thaia the outer. Its articular surface is broadly continuous with those of the condyles; a slight emargination of the outlines only marking the usual constriction on each side. In this it resembles Cervidce and some Antilopidce The inner con- dyloid surface is cut ofi" by the emargination in Toxodon and Bos huhalus; the emarginations are deep, but do not cut off either, in Equus, Camelopar- dalis, and three species of Bos ; while they arfe so deep as to cut off both in Bhinoceros, 5 sp.. Hippopotamus, Bos hrachycerus, B. sondaicus, and in Catoblepas. The fihida has the inner sharp edge prolonged to the proximal end : the form of the latter is much as in JEobasiletis. The astragalus is slightly con- cave in both directions on the trochlear face, most so anteroposteriorly. The anterior outline of the same is strongly and obliquely convex, and the sui-face is produced sideways into a lateroanterior apex. The inner malle- olar border is thiis very concave; the outer is gently convex with a long fibular facet. The posterior margin is concave, the inner tuberosity pi'omi- nent. The navicular facet is as broad as long, and nearly sessile, being 548 THE WASATCH AND BRIDGER FAmf^. probably separated b}- a groove from the tibial. The cuboid facet is sub- round, small, and siiblateral. The calcaneal are situated diagonally opposite each other. The anterointernal is twice as large as the other, and is trans- verse and truncate internally by a facet near the apex, at right angles. The other calcaneal facet is subround. Measurements. M. Longitudiual di.imeter of last superior molar 035 Transverse diameter of last superior molar 0455 Lougitudinal diameter of peuullimate 032 Transverse diameter of penultimate 039 Longitudinal diameter of posterior premolar 024 Transverse diameter of posterior premolar 0:!4 Longitudinal diameter of anterior premolar 0215 Transverse diameter of posterior premolar 0265 Lengtli of premaxillary bone 082 Transverse width of posterior suture 628 Width of premaxillary at middle suture 043 Length of basis of last two inferior premolars 057 Transverse diameter of edge of mandible at first premolar. 017 Length of ramus mandibuli to anterior margin of coronoid process 310 Leugth of premolars and molars 218 Length of last molar crown 040 Width of last molar crown 030 Width of last premolar crown 018 Length of last premolar 025 Width of symphysis at canines ^ 045 Diameter of canines 2 028 Diameter of canines 2 023 Length of exposed portion of incisor 2 026 Width of crown of incisor 2 0245 Length of diapophysis atlas 047 AVidth of diapophysis atlas 056 Width of facet for axis ^ 053 Width of glenoid cavity of scapula (straight) 086 Length of coracoid from inner basis 045 Diameter of condyles of femur 104 Diameter of head and great trochanter 130 Diameter of head alone 062 Diameter of shaft with third trochanter 076 Supposed length of femur (16.75 inches) 415 Transverse diameter of head of tibia 092 Anteroposterior diameter, internal ,061 Anteroposterior diameter, external 045 Length of proximal articulation fibula 027 Length of distal articulation fibula . 042 Diameter of shaft of fibula 042 Total length of astragalus (fore and aft) . 072 Total width of astragalus ! 065 Length of navicular facet 045 Width of navicular facet 034 BATHMODON. 549 ii. Width of cuboid facet 025 Length of cuboid facet 0-23 Length of anterior calcaneal facet Z .' 040 Width of anterior calcaneal facet _ 024 Length of posterior calcaneal facet 021 Length of fibular (axial) 043 From the Wasatch Lower Eocene at Evanstou, Wyoming. Numerous specimens of teeth of both jaws obtained by myself in New Mexico, and by Mr. Wortman in the Wind River and Big Horn regions of Wyoming, agree closely with those found with the bones of this species. In lack of diagnostic bones it is not possible to identify them positively with the B. radians. A humerus having much the character of that of this species is figured on Plate LIV, fig. 5, of my Report to Capt. G. M. Wheeler. Bathmodon pachypus Cope. Proceedings Academy Philadelphia, 1882, p. 294. Plates XLlVc; XLlVd; XLIVe; figs. 7-13. The largest species of the Pantodonta yet known is represented by portions of two individuals. Neither of these includes any teeth, but the characteristic bones of the skeleton have been preserved. They indicate an animal of the dimensions of the middle-sized species of Uintatherium, but with shorter legs. All the specimens were found by Mr. J. L. Wort- man in the Wasatch beds of the Big Horn Basin of Wyoming. It is possi- ble that some of the large teeth of the collection made by Mr. Wortman belong to this animal, but there is as yet no means of pi'oving the connec- tion. One of the specimens includes a large part of the humerus, with head of radius ; pelvis entire ; femur entire ; and a good many carpal and tarsal bones, metapodials, and phanlanges. The only cranial fragment is a man- dibular condyle. The bones of the fore limb and foot do not differ from those of the specimen above described, except in their superior size, with the following exceptions : The outline of the proximal extremit}- of the great trochanter is a semicircle rather than a triangle. Thei'e is little indi- cation of the tuberosity of the superior border of the head of the radius. The proximal end of the pisiform is preserved. It is more expanded trans- versely than the distal extremity, as I have represented in figs. 2 and 5, Plate LIX, of my report to Captain Wheeler. 550 THE WASATCH FAUNA. Measurements of fore limb. m. Transverse diameter of humems ^ I"'°^^'"''l ^"'^ ^^* t distal end 151 Width of head of radios 082 Length of pisiform .; 064 Width of pisiform proximally . 055 C transverse 065 Diameters unciform< anteroposterior 051 ( depth in front (greatest) 032 {anteroposterior 054 transverse in front 027 vertical i-ifr""* 019 < medially 039 The width of the condyle of the mandible is M. .102. As no complete pelvis of a Coryphodon has been hitherto procured, I describe the present specimen in detail. Its expanded ilia present the un- gulate type, and the wide peduncles resemble those of the elephant. The plate is, however, not so expanded anteroposteriorly as in the genus Elephas, and the crest is more convex. If the crest of the ilium of the camel were considerably more convex, the bone would resemble that of this species of BatJimoclon. It is less dilated anteroposteriorly than in Bhinocerus sp., and has a stouter peduncle than in that genus, Eqims, Tapirus, or Sus. The symphysis is shorter than in any of the genera above mentioned. This is partly due to the fact that the posterior parts of the ischia are not so wide anteroposteriorly as in any of them, the nearest approach being seen in Bhinocerus. The obturator foramen is larger than in any of these genera, excepting Bhinocerus, and there is no tuher ischii at all comparable to what is seen in all those genera. The pubes are slender, and are not so trans- verse as in those genera, but slope posteriorly. The notch of the acetab- ulum is opposite the shaft of the ischium, and not opposite the obturator foramen, as in all the genera named. The sacral articulation is rather long and mai'ks a bevel of the edge of the plate of the ihum. Measurements of pelvis. m. Axial length 572 Axial length of ilium .340 Width of plate of ilium 340 Width of peduncle of ilium 112 Length of pubis 140 Long diameter of pubis at middle 030 Length of ischium 125 Long diameter of ischium at middle 065 Length of ischio-pubic symphysis 090 Length of obturator foramen 106 Width of obturator foramen 070 BATHMODON. 551 There is no important difference between the femur and that described vinder C. anax, excepting the superior size. The little trochanter is not quite so prominent in the larger bone. Measurements of femur. Length 500 Width proximally with great trochanter 165 Transverse diameter of head 085 Width at third trochanter 105 Width of shaft below third trochanter 077 Width at epicondyles 138 Anteroposterior diameter inner condyle 092 Anteroposterior diameter outer condyle 074 The astragalus has the characters of that of B. radians, with an ap- proach to some of those of CorypJiodontes. The internal hook is well devel- oped, and is recurved so that its posteriorly-directed apex is separated by a deep notch from the posterior median tuberosity. In C. latipes and other species the apex is directed inwards and not backwards. This is a well- marked character, and one in which it resembles the Bathmodon radians; but in that species the internal hook is still shorter, though its tibial face is not carried so far posteriorly. The apical facet, mentioned as character- istic of the genus Bathmodon has the same relative size and proportion as in B. radians, but its suiiace is not cut off from the anterior part of the apex by a deep groove, as in that species. A comparison of the inferior side with that of the astragalus of B. radians, displays the following differences : The external facet in the latter is cut off from the posterior tuberosity by a deep groove, which is continued from a deep notch in the posterior border of the bone. In B. pachypus the notch is very shallow, and the groove is not connected with it, the external facet being continuous with that on the inferior side of the posterior tuberosity. The notch is more apparent on the superior than on the inferior side of the astragalus in the B. pachypus. In the latter, the anterior inferior facet is separated by a wide space from the supernumerary internal facet; in B. radians they are almost in contact. The anterior facet is absolutely smaller in the B. pachypus, and is more largely extended on the posterior tuberosity than in B. radians. Both the navicu- lar and cuboid facets have greater transverse extent in the B. pachypus, and the latter extends to behind the middle of the former, which it scarcel}^ does in B. radians. 552 THE WASATCH FAUNA. Measurements of astragalus. m. T^. . J. i < anteroposterior 080 Diameters, greatest < ' noj ( transverse "''' C vprf iofll - ..,-•••••••••■•■-•••••■•■•••- i\)*'' Diameters navicular facet ( „/,(, ( transverse ""^ Diameters cuboid facet < f>t;i ( transverse "^'■ Depth of fibular facet 02o Transverse width of anterior inner astragalar facet , "•^"2 The calcaneum differs decidedly from that of Coryphodon max. While its general dimensions are greater, the length is the same. The section of the posterior extremity is a transvere parallelogram; in the C. anax it is square. The sustentaculum has two facets, a superior narrower, and an anterior; the C. anax has the anterior only. In the former the posterior face of the sustentaculum rises to the posteinor edge of the facet; in the B. jiachypus it has a superior surface, which is separated from the superior facet by a groove. The cuboid facet is transverse and extends inwards, overlap- ping the sustentacular; in C. anax it is very oblique, and does not reach the sustentacular. The median inferior tuberosity of the distal extremity is present in both species, as is the inferior marginal crest of the distal half of the internal side. In both species this ridge shows two oblique grooves, which perhaps accommodated the tendons of the tibialis posticus and flexor digitormn muscles. In this order there is no groove of the cuboid bone to accommodate them. Measurements of calcaneum. ' m. Total length 1*''' c vertical - - ^^^ Diameter of free end < ^.c, ( transverse "OJ- Width at sustentaculum 095 Width of cuboid facet 049 Greatest depth of facet 026 The calcaneal and astragalar facets of the cuboid are about equal, and make a strong angle with each other; the calcaneal is the more oblique to the distal face. The distal extremity is subquadrate, the anterior three- fifths being occupied by the two metatarsal facets, which are little distinct from each other. The external is less than half as large as the internal. Measurements of cuboid. m. I vertical iu front 031 Measurements < anteroposterior below 050 ( transverse below ' O.iO Length of a metopodial bone 080 Diameters prosimally I ^^ eropos eiior ( transverse "jo Diameters distally \ anteropost. { transverse BATHMODOK 553 u. -erior 0i>8 040 Uroximally^'^"*"°P°«*<'"<"" 037 Diameters of a phalange < < transverse 0'24 ( longitudinally (lateral) 022 A second individual, apparently, of this species is represented by an entire humerus and radius. The articular extremities of the humerus and radius agree closely with those of the specimen first described, differing only in being a little larger. The humerus differs from that of Coryphodon anax much as the calca- neum of the first described specimen does from the corresponding bone of the latter species. It is nearly identical in length, but considerably more robust in every part. In the size of its articulations it equals some of the large species of Uintatherium, but the shaft is relatively longer in the latter. The radius is also remarkable for its very robust form and the large size of its articular extremities. The head resembles that of the specimen first described ii^ wanting the prominent tuberosity of the superior border found in C. anax. There is, however, a convexity in the corresponding position in the B. pachyjms. The inferior surface next to the ulnar band is rough, with longitudinal ridges and grooves, but there is no defined fossa. The long axis of the distal extremity is oblique to that of the head, the external face looking outwards and upwards. The carpal face presents several peculiarities in which it differs much from the corresponding part of a Corypliodon figured on Plate LXIV, fig. 6, of my final Report to Captain Wheeler. The carpal facets only occupy a part of the extremity of the bone, which is much expanded outwards. On this obliquely truncate club- shaped extremity the long axis of the facets extends backwards and out- wards, their margin only coinciding with that of the former at the point of contact with the ulna. The facets for the scaphoid and lunar are distinct, the former being plane, the latter concave. The scaphoid, moreover, has only about one-fifth the area of the lunar, a relation quite different from that which prevails among mammals generally. The extremity has a liga- mentous fossa between the scaphoid facet and the internal border of the dimensions of the lattei'. The ulnar face is not distinct. There is an angular ridge just above the external border of the head, and another on the inner side, defining it from the inferior side just above the head. There are no distinct grooves of the supero-external surface. 554 THE WASATCH FAUNA. Measurements. M. Length of shaft of humerus 400 Width at middle 085 Width at epicondyles 163 Width of condyles 115 Diameter of head anteroposteriorly 105 Diameter heads of radius J ^■'''^"'"*^ °f^ < transverse 083 Length of radius 260 Greatest width of distal end radius 090 Diameters scaphoid facet ^■'°*'^™P<'«'«"°'■ "^ ( transverse 020 _. . , „ ,< anteroposterior 051 Diameters lunar lacet < ' ,,„ ( transverse 058 Long (transverse) diameter of shaft at middle 048 From the preceding it is evident that this species is distinguished for its robust form, as indicated by the proportions of its legs and feet. It is the heaviest species of the Coryphodontidce yet known. METALOPHODON Cope. Proceed. Amer. Philos. Soc, 1872, p. 542, Sept. 20. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 589. This genus differs from Coryphodon in the structure of the true molar teeth; the formula is the same as in that genus: I. 3; C. 1; Pm. 4; M. 3. All the premolars have a single external V, extended well inwards, and a single internal cusp, whose anterior and posterior edges are continued into cingula which extend along the anterior and posterior bases of the external V. The first true molar, like that of Coryphodon, has two external V's, but the anterior is represented by a subconic cusp, while the posterior is large, and is well produced inwards to its apex. The anterior basal cingulum of the premolars has become an elevated transverse crest of the crown, termi- nating in the crescent-edged single inner tubercle. The second true molar, instead of resembling the first, as is the case in Coryphodon, is like the third or last true molar in its structure. In both molars the posterior external V has become a stout transverse crest, connected with the subconic repre- sentative of the anterior V, the two forming a cross-crest nearly parallel to the anterior cingular cross-crest. They are separated from the latter by wide interruptions at both extremities. The canine in the only known species, is compressed, and has a wide groove extending along its posterior edge. METALOPHODON. 555 The existence of the posterior transverse crest on the second true molar constitutes a point of nearer resemblance to the Eobasileidoe than is found in the other known Coryphodontidce. Metalophodon armatus Cope. Proceed. Ainer. Philos. Soc, IriTi, p. 54-3. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 589. Plate xlix, tigs. 1-7. This, the only known species of the genus, was found by myself near Black Butte, Wyoming, in the Wasatch formation. The typical specimen consists of a number of teeth of both jaws which I took from two decayed skulls which were partly exposed in a bank of argillaceous material. These skulls were lying close together,, and belonged to an adult and young ani- mal, respectively, as indicated by the relative wear of the teeth. The adult series consists of three incisors, two superior premolars, and three superior true molars, with three inferior premolars. The young animal is repre- sented by one incisor, the superior and inferior canines, three superior pre- molars, and two superior true molars ; also by one inferior premolar and one inferior true molar. The second true molar of the younger specimen is unfortunately wanting, so that it cannot be demonstrated that it belongs to this species, but the other teeth, especially the first and third true molars, correspond so closely as to induce me to suspect that the two animals were members of the same species, and probably of the same herd. I first describe the teeth of the adult : The incisors are well developed, those of the premaxillary subequal in size. The crown has a convex cutting edge and flat inner face. The outer face is convex. In some the inner face is more concave, and is bounded by a weak cingulum next the root. The superior premolars present a single external crescent of acuminate outline, and a smaller, more transverse one, within. A cingulum bounds the crown fore and aft, but is wanting at both external and internal bases of the crown. The posterior sends a branch to the apex of the internal lobe. In the fourth the crescent is more open and the crown less transverse. The first true molar presents an increase in transverse extent of the posterior external crescent, and the anterior one is a flattened cone. In 556 THE WASATCH FAUNA. the posterior two, the anterior ridge curves round at the apex, but is separated by a considerable interruption from the posterior. The latter is shortened, and terminates externally in a conic tubercle, which approaches the recurved outer extremity of the anterior ridge. In the last molar the posterior ridge is shorter, nearly straight, terminating abruptly at each extremity. On all the tiiie molars there is a strong anterior basal cingulum below the anterior transverse ridge. In the first there is also a strong pos- terior basal cingulum ; but this is wanting from the second and third. A short curved cingulum passes round the base of the internal extremity of the posterior crest, but none passes around the interior or exterior base of the anterior crest. The inferior premolars are represented by the first, third, and fourth. The first has but one root. The crown is compressed, and the posterior heel is very short, consisting of a median keel and two cingula The posterior external basal angle of the V is very prominent in this species in the pos- terior premolars, as in Coryphodon It is much more elevated than the posterior basal angle. The heel has considerable transverse extent in the fourth premolar, the internal cingulum expanding into a table. The cin- gula do not extend to the internal or external bases of the crown. The teeth of the 3-ounger animal present the following characteristics: The canines are damaged, but were of large size, amounting in the upper jaw to a tusk. The superior is compressed, with acute edges. The inner face is gently convex, the outer more strongly so, with an acute ridge on its anterior convexity inclosing an open groove with the interior cutting edge. The surface of the dentine, when exposed, has a transversely wrinkled character, but no trace of engine-turning in the fractures. The inferior canine is subequilaterally triangular in section at the base. The posterior face is slightly convex, and is separated by a very prominent angle from the external face. The latter is concave next this crest-like angle, and is convex anteriorly. The first superior true molar is similar to that of the adult specimen, and is unworn. The large posterior external V is nearly flat on its externo- superior face. The cingula do not pass round the internal base of the crown. The enamel is finely wrinkled ; it is thrown into vertical ridges on PANTODOXTA. 557 the inner convex extremity of the crown. Similar ridges are prominent in the corresponding part of the crown of the last superior molar. The last inferior molar has a distinct but rather narrow posterior heel, and there is 110 accessory tubercle or accessory ridge as in the typical species of Cory- j)hodon. The size of this species is about that of the Bathnodon radians. Measurements of the teeth. No. 1. M. Total length of .superior incisor 0.'57 Leu<;th of crown (inner face) superior incisor 015 Will I h of crown (oblique) superior incisor 0"20 Width of crown (oblique) inferior incisor — 0^-' Length of crown (inner face) superior incisor 018 "Width of posterior molar 0:59 Length of posterior molar 028 Elevation of posterior crest of molar 010 Width of anterior true molar O.iS "Width of premolar 028 Length of premolar 0.1.5 Length of premolar (tirst) 016 AVidth of premolar (first) 008 Length of premolar (inferior) 024 AVidth of premolar (inferior) 02U No. 2. "Width of superior canine .030 from apex 020 "Width of inferior canine at external base 028 _. ^ r XL ^ • _, 1 < anteroposterior 033 Diameters of first superior molar { , "^ „.,_ < transverse "•'' Width of last lower molar 023 Length of last lower molar 037 MtTALOPHODON TESTIS Cope. Paleoiitological Bulletin, 34, Feb., 1882, p. 175. Proceed. Amer. Philo. Soc, 1881, Dec, 175. PlateXLIVa; fig. 13. The genus MetalopJwdon was described by me in 1872. Up to De- cember, 1881, it had remained without further illustration of importance, as no good specimens of it had been obtained by any of my expeditions up to that year. The material then obtained consists of the entire superior molar series of the right side, and the superior molars of the left side, in beautiful preservation. These display the characters on which the genus was proposed, i. e, the conversion of the posterior external V of the second 558 THE WASATCH EPOCH. true molar into a transverse crest similar to that of the last true molar. It follows that the first true molar is the only one which exhibits this V. It also follows that in this genus the peculiarities of the dentition of Cory- phodontkloe are carried further than in CorypJwdon, where two molars display the V, and one the crest; or than in Manteodon, where all three have a V, and none the crest. The genera then stand in the order of evolution, Man- teodon, Coryphodon, Metalphodon. The first superior premolar has lost its crown. The other premolars do not display any marked peculiarities. The internal cusps are well devel- oped, and are most prominent posterior to the line of the apex of the exterior crest. They connect with the posterior cingulum by a broad ledge, but do not connect with the anterior cingulum. The two cingula nearly connect round the inner base of the crown on the third premolar. The first true molar is well worn. The base of the posterior external V can be seen, and the anterior and posterior cingula. There is no internal cingulum. The second true molar is the largest of the teeth. It is sub- triangular in outline, its external side forming, with the posterior, a right angle. Its general character is much like that of the Coryphodontes, but it presents the remarkable exception which constitutes the character of the genus Metdopliodon. The posterior crest does not include a V, but is straight, and consists of the same elements as the posterior crest of the third true molars, but diff'erently proportioned. The part representing the ante- rior V is a cone, much shorter than the part corresponding to the posterior V. As there is a postero-exterior angle of the crown there is an oblique surface rising to this part of the crest, which represents the external face of the V. There is also a small tubercle at the angle, where a similar one is found in the corresponding tooth of Edacodon cindus. Altogether this tooth is like the posterior molar of Coryphodon elephanfopus, with a more prom- inent postero-external angle added. The anterior and posterior basal cingula are well developed, the latter being strong interiorly to the point where it sends a branch upwards to the internal cusp. There is no internal cingulum. The last superior molar is a transverse oval, more regular than usual in the species of Coryphodon, since the diameters of the internal and external portions are about equal. The characters of the posterior crest differ from DINOCEEATA. 559 those seen in the genus named in that the internal portion is much smaller than the external, having a small conic apex, distinct from that of the exte- rior portion. Its postero-external face is nearly vertical, and it diverges a little posterior to parallel with the anterior crest. The latter (the first cin- gulum) is elevated, and is wideh* separated externally from the posterior crest, to whose base it descends on the external extremity of the crown. The basal cingulum is present all round the crown except at the base of the posterior crest, and externally. It is narrow on the inner extremity of the crown. It sends upwards a strong branch to the apex of the internal cusp. The enamel of all the molars is strongly wrinkled, but is worn smooth wher- ever rubbed. Measurements. m. Length of superior molar series 179 Length of premolar series 085 DiametersP-m.ii^'^°t«™P"«'*^"<"" ^^^ < transverse 025 Diameters M. i 5 ''"''''■"P*'^*''''" ^^^ ( transverse 032 Diameters M.ii^'*"*''™P°^t«™"^ 036 ( transverse 042 I anteroposterior 0285 DiametersM.iiis transverse 041 ( vertical 015 The Metalophodon testis differs from the M. armatus in the more trian- gular form of its penultimate superior molar. Its form is quite different from that of the last molar, while in 31. armatus the two teeth resemble each other closely. The species are of about the same size. The individual from which the above description is taken is rather aged. DINOCERATA. The characters of this suborder have been already pointed out and discussed. The differences from the Pantodonta are well marked, but the resemblances are such as to render it impossible to refer the Dinocerata to a different order. Their strong resemblances to the Prohoscidia are gener- ally admitted, but the few characters Avhich distinguish them are of the first importance. These are, first, the very small size of the brain, es^^e- cially of the cerebral hemispheres, and, second, the double distal articula- tion of the astragalus, where the facet for the cuboid bone is nearly as large as that for the navicular. 560 THE BEIDGEK EPOCH. Within the above definition there is room for much variation, which, however, the known genera do not display. They agree in various points of minor importance Thus there is no sagittal crest of the skull, the tem- poral ridges being lateral, and there is a great supraoccipital crest. These crests are more or less furnished with osseous processes or horns. One of these consists in part of the maxillary bone, and stands in front of or over the eye. The nostrils are well roofed over by the nasal bones. There is always a diastema behind the canine tooth in both jaws. Tliere is less difference between the ])remolar and molar teeth in the known genera than in the Pantodonta, and they are all constructed on the same pattern. Thus in the upper jaw the crowns of the molars support two oblique cross-crests, which unite to form a V with the apex inwards. There is no internal cusp or tubercle. The inferior molars consist essentially of an outer Y and a heel; the true molars differ in having the heel a little larger, and more recurved on its posterior bordei', but it does not rise into a transverse crest, as in the Coryiilwdontidoe. Messrs Spier, Scott, and Osborne show that the inferior incisors in Loxolojihodon are compressed and two-lobed. In LoxoJophodon the malar bone forms the middle elemenf of the zygo- matic arch, sending a narrow strip only forward to the neighborhood of the lachrymal. In Uintatherium, according to Marsh, its extension towards the side of the face is rather greater, much as in some Perissodactyla. The known genera agree with the typical Proboscidia in the posterior expansion of the scapula, and its apical acumination, in the short cerv- ical vertebi-se, in the flat carpal bones, in the absence of pit for round liga- ment of the femur, in the flattened gi'eat trochanter, contracted condyles, and Assure-like intercondylar fossa of the same bone : in the longitudinal crest of the tibia separating glenoid articular faces which are on a transverse line. Also in the short calcaneum, which is wider than long and tubercular on the inferior face; in the five digits, the acetabulum not separated by a peduncle from the iliac plates, and the lack of angular production of the latter beyond the sacrum. Genera. — Owing to the imperfect character of the material which I have had the opportunity of examining, it is not possible to state the num- ber of these with absolute certainty. There are certainly three of these, and probably four. So far as present knowledge goes, they pertain to one DINOCEEATA. 561 family, which I have called the Eohasiliidoe. The three genera mentioned differ in the forms of the mandible; the fourth has certain cervical vertebrae of a peculiar form, but the form of the mandible is unknown. I can only contrast the genera as follows : A Mandible unknown. Certain cervical vertebrae short and flat, as in Proboscidia Eobasihus. A A Symphysis of mandible with four teeth on each side, a Mandible without inferior expansion. Cervical vertebrae not very short Loxolophodon. y Mandible expanded below, its entire length. Cervical vertebrae unknown Bathyopsis. AAA Symphysis of mandible with three or two teeth on each side. Mandible with very narrow symphysis Uintatherium. History, <&c. — I originally* referred the Eobasileidce to the Proboscidia on account of the structure of the limbs, and subsequently stated a number of reasons for this conclusion at a meeting of the Academy Natural Sciences of Philadelphia, held January 14, 1873 (published January 16.) In the present paper numerous confirmatory characters are added. The Bathmo- dontidce I at first referred to the Perissodactyla. Professor Marsh, in describing a species of this group, Titanotherium (?) anceps (July, 1871), compares it with Perissodactyle species, and in describing the tibia says that it, "at its proximal end, has the femoral sur- faces contiguous, with no prominent elevation between them, resembling in this respect some of the Proboscidia." A few days before the publication of my conclusions, in a foot-note (July 22, 1872) he altered the name Titanotherium to Mastodon, thus indicating that the species is a proboscidian. Shortly after (American Journal of Science and Arts, September 27) he altered his view, constructing a supposed new order, ^^ Dinocerea," for their reception. EOBASILEUS Cope. Proceed. Amer. Philos. Soc, 1872, p. 485. Palaeontologioal Bulletin, No. 6, p. 2, Aug. 20, 1872. Annnal Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 575. This genus was established on a species which is represented by a con- siderable part of the skeleton, but without cranium or teeth; hence most • Paleontological Bulletin No. 6, August 20, 1872, p. 2, reprinted in the Proceedings of the Amer- ican Philosophical Society of like date. 562 THE BEIDGER EPOCH. of its characters remain unknown. The very short cervical vertebra which belongs to it serves to distinguish it from other genera. (See Plate XXX, Fig. 3.) A second specimen {E. furcatus) found near the first may belong to it; it includes a fragmentary cranium, but unfortunately no cervical ver- tebrae. Its introduction into this genus is therefore purely arbitrary. The typical species is of large proportions, only second in size to the Loxolophodon cornutus. EOBASILEUS PRESSICOENIS Cope. Loxolophodon pressicornis Cope. Proceed. Amer. Philos. Soc, 1872, p. 580 (published August 19). Loc cit., p. 488 (August 22). L'obasileus cornutus Cope, 1. c, p. 485 (August 20), not Loxolophodon cornutus Cope, 1. c, August 19. Eoiasileus pressicornis Cope, Annual Report U. S. Geol. Snrv. Terrs., 1872 (1873), p. 575, portion. Plate XXX, figs. 1-5 ; Plate xxxi. The typical specimen embraces cervical, dorsal, and lumbar vertebrae, ulna, both femora and tibiae, astragalus, navicular, &c., and large pai'ts of the scapulae and pelvis. The scapula, in its proximal portions, differs in little fi'om that of Loxo- lopliodon cornutus, besides its inferior size. The coracoid is a compressed tubercle inclosing a groove with the glenoid cavity. M. Diameter of glenoid cavity (longitudinal) 168 Diameter of glenoid cavity (transverse) 098 The OS pubis displays a strong pectineal rugosity, commencing near the acetabulum. M. Long diameter of acetabulum 143 Length of common public suture 108 Diameter of pubis, near acetabulum 052- The femur is nearly as long as that of Loxolophodon cornutus, but is more slender, and has a relatively smaller head. It is flattened fore and aft, and the great trochanter is much expanded and with a shallow con- cavity on the posterior face. There is a marked concavity on the posterior face of the shaft above the condyles. There is a rudiment of the little trochanter. The tibia is scarcely three-fourths the length of the femur, and has a rather contracted shaft, which is in section rounded triangular, one angle presenting forwards. There is no spine except a rudiment in the swollen upper portion of the anterior ridge. The ai'ticular surfaces are DINOGERATA. 563 together rather narrowl}' transverse. They are separated by a keel which is undivided posteriorly ; anteriorly, the contiguous margins of the cotyli separate. The long axis of the inner of these is directed anteroposteriorly outwards in front; of the other, similar but much more transverse. It overhangs the shaft outward and backward, and supports beneath the sub- roiind down-looking fibular articular surface. The distal articular surface is distinguished from allied species by the downward prominence of the malleolar process, the anteroposterior width, and the greater extent of the fibular articular face. The face is slightly concave anteroposteriorly, and openly sigmoidal transversely. Measurements of leg. Length with astragalus in place 1.200 Femnr, length 750 Femur, diameter of ball 118 Femur, width at great trochanter 220 Femur, width at middle shaft 091 Femur, depth at middle shaft 060 Tibia, length .' 470 Tibia, width of proximal surfaces (transverse) 147 Tibia, width of proximal surfaces (anteroposterior) . 070 Tibia, transverse diameter of shaft 061 Tibia, anteroposterior shaft 065 Tibia, anteroposterior shaft, distal articulation 092 Tibia, transverse shaft, distal articulation 121 Fibula, length 430 Fibula, transverse width at middle 032 Fibula, width of proximal articular face 042 Fibula, width of malleolar articular face (transverse) 0.=i2 Fibula, width of malleolar articular face (longitudinal) 044 A section of the fibula, near the proximal end, is subtriangular ; a short distance below, subcircular ; on the distal two-thirds it is flat, with the thinner edge convex inward. The astragalus is a flat bone, with its entire superior face occupied by the tibial articular surface. This is as broad as long, and very little con- vex. It is broader in front than behind ; the outer margin is concave, the inner slightly convex. The posterior margin projects most on the outer side, and it is divided by a pit-like cavity, which sends a groove to the inner margin. The outer malleolar surface is an anteroposterior oval ; the inner, a concavity, beyond which the inferior portion of the bone projects. The inferior face is divided by a prominent transverse angle, between sub- 564 THE BEIDGER EPOCH. anterior and subposterior faces. The latter receives the calcaneiim on two oval surfaces, which are joined behind by a narrow strip. The navicular face is subrhomboid, the cviboid one-third as large, and triangular, with a round base outwai-d. The margin of the former scarcely projects beyond the superior face. Measurements of astragalus. II. Total width 128 Total length 107 Width of tibial face in front 090 Length of tibial face, externally 088 Length of internal malleolar face 045 Length of outer calcaneal, malleolar face, anteroposteriorly 050 Length of navicular facet 085 Width of navicular facet (anteroposterior) 06O Length of cuboid facet 065 Width of cuboid facet (anteroposterior) 035 The centrum of a cervical vertebra, which lacks epiphyses, is very short, and the articular face is a wide, transverse oval. Both are slightly concave, and the axis being slightly oblique, the anterior is the more elevated. The surface of the latter is quite rugose, except on the margins. The cervical canal is wide, and the neurapophyses and parapophyses narrow. Inferior surface regularly convex. Measurements of cervical vertebra. M. Length of centrum 044 Length of basis of neurapophysis 040 Length of anterior articular face 102 Depth of anterior articular face 086 Width of neural canal at base 060 The centra of the dorsal vertebrae are too much distorted by pressure for description. This amblypod was a huge animal, little less elevated than the Loxolo- phoclon cornutus. Its limbs were more slender in their proportions. It is in this species that I find much evidence in favor of the presence of a pro- boscis of greater or less length. Should several of the other cervical ter- tebrse have been as short as the one preserved, it is evident that the animal could not possibly have reached the ground with a muzzle so elevated as the long legs clearly indicate. The reader is referred to Plates XXX and XXXI for the evidence in pictorial form. DINOGEEATA. 565 The bones above described were discovered b}- the writer in an amphi- iheater of the bad lands of the Washakie Basin, known as tlie Mammoth Buttes, in Southwestern Wyoming. They were in greater or less part exposed, lying on a table-like mass of soft Eocene sandstone. A descrip- tion of this remarkable locality is given in the Penn Monthly Magazine for August, 1872. EOBASILEUS FURCATUS Cope. Xoxolophodoti bifurcatus Cope, in extra copies on Proboscidians of the Eocene of Wyoming, August 19, 1872.* Loxolophodon furcatus iu the s.ame, Proceed. Amer. Philos. Soc, 1872, p. 580, August 20. L. c. 488, August 22. Eobasileus furcatus Cope, Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 580. Plates xxxii, xxxiii. This species was originally described from a posterior horn, which was obtained near the locality which furnished the typical specimen of ^. pressi- cornis. It was found in an old camp separate from the other specimens. The trail from this camp passed the front of the bad-land bluffs, and where it reached the foot of the latter I found projecting from the rock parts of a .skull and skeleton, M^iich I suspect to be the animal to which the horn belonged. It is very probable that the horn was picked up at this point, although, of course, there is no direct evidence to that effect. It is repre- sented in Fig. 5, Plate XXXIII, and presents the following characters: The basis is very naiTOw and lenticular; a short distance above it the outer side is convex. The anterior and posterior extensions of the base differ; the one is thinner, the other more massive and with a shallow groove above its commencement. The latter is posterior. The compressed apex of the horn-core sends down a rib outwardly to the anterior base and one inwardly, which disappears on the convex base. The general form is spatulate, with the apex expanded obliquely across the lateral crest of the skull, and regularly rounded in superior outline. Its anterior face is flat, the posterior convex; its surface is grooved by very small blood vessels. As compared with the posterior horn-core of Loxolophodon cornutus, there is every difference. That is continuous with one margin of the crest, ihis erect above it; that has a round base, this a lenticular one. It is more *See Proceed. Amer. Pbilos Soc, 1872, p. 515, where this name is recorded. 566 THE BRIDGER EPOCH. like that of Uintatherium mirahUe, Avhicli I only know from Marsh's figure, but is abundantly distinct. It is much more elongate, especially above the (?) posterior part of the crest, and is flattened, and not triangular in section as in that species. Measurements of horn-core. The total length above crest (5.5 inches) 135 The total length above anterior base (7J inches) 180 Width across apex (in front) 095 Thickness across apex (in front) • 028 Thickness at base 040 The supposed remainder of the sj^ecimen (Plates XXXII, XXXIII, Figs. 1-5) includes various parts of the cranium, without teeth; portions of the atlas, femur, and fore and hind feet. The fore part of the nasal bone is preserved. The apex is rather acuminate, and its profile forms a descending curve continuous with the superior plane. The tuberosities are mainly lateral, and cause an abrupt expansion of the lateral outlines. Their obtuse external face is longitudi- nally oval, and descends slightly backward. The inferior lateral marginal ridge is contracted, and incloses a concave median space. The tuberosity sinks to the level of the median suture. The posterior part of the nasal rises to the apex of the middle horn-core, forming its inner face. The postero-superior angle of the premaxillary reaches to near the base of the horn, and is not drawn out to a narrow apex as in L. cornutus. The horn is compressed anteroposteriorly at the base; at the apex obliquely inward and forward. The outer face is concave on the lower half, the inner, con- vex. The posterior face is concave and the anterior convex, when viewed from the side in profile. Measurements of front. if. Width of both nasal bones at tuberosity 124 Width of both at base of distal cone 060 Depth of suture at front of tuberosity 030 Length of suture, from premaxillary to horn-core 035 Length of born-core (in front), (6 inches) 150 Diameter (externally) 080 Diameter of apex . 048 The occipital region is furnished with an enormous transverse crest which extends upward and backward. Its margin is gently convex, and its DINOCERATA. 567 superoanterior face concave. The posterior face is narrowed by the inferior crest-hke marginG of the temporal fossse, which extend from the squamosal part of the zygoma and gradually contract, terminating abruptly in a low knob where it joins the transverse crest. The posterior face between the former, is divided into two planes by a low vertical ridge, which terminates some distance below the summit. The transverse crest is continued in a curve forward on each side as the superior margin of the temporal fossa. These are very stout, but are broken off near the position of the horns. Measurements of occiput. M. Elevation from foramen magnum 0. 180 Width between inferior temporal crests 250 Width of condyles with foramen 180 Elevation above internal sinnses at angles 180 The mastoid tuberosity is short and stout; the mastoid foramen is large and not piercing a crest. The ex-occipital suture is obliterated. The V- shaped crest behind the meatus in Loxolopliodon cornutus is little marked here. The surface of the bone has various muscular impressions. The basi-occipital exhibits a low median crest dividing lateral concavities; trans- verse width at condyles .077 M. The fragments of teeth are too uncharac- teristic for specific description. Numerous cranial fragments accompany the above, but have not yet been properly placed. The atlas is broken; its cotyloid cavities are rather shallow, and the diapophyses small. Its anteroposterior diameter below at the middle line, is .070; at base of diapophysis .070. The condyles of the femur present the characters of the group. There is a deep vertical groove on the inner side just above the condyle. The latter approach each other closely on each side of the intercondylar fossa and are flattened on the superior poste- rior margins. Width across extremities M. .150. The unciform bone is in form a little less than a quarter of a circle, and the external (anterior) depth is one-half its transverse length. Its superior surface is slightly convex. It displays, as in living proboscidians, four in- ferior facets, thus proving the existence of a fifth toe to the hind foot. The external facet is deeply concave, and contains a pit. It is oblique, and unites with the superior face by an acute angle. The internal inferior 568 THE BRIDGEE EPOCH. facet probably supported the small inner toe by its metatarsus directly. The other two are more nearly on one plane, and are deeper than wide. Measurements of unciform. v. Depth in front ; 048 Width (transverse) 097 Width of external facet 035 Width of second facet ^ 026 Width of third facet 047 Width of internal facet .023 On account of the absence of corresponding parts, it is not possible to be certain whether the individual above described belongs to the species Eohasileiis pressicornis or not. It is possible that the bones belong to the same individual as that described under the latter name, although the locali- ties where they were found are about one hundred yards apart. At about the same distance from both the above specimens I found a humerus, which I describe briefly. The distal articular face is very oblique to the trans- verse axis, but is about equally developed on opposite sides of the shaft. The condyles are unequal, have parallel axes, and are hour-glass shaped, with a shallow concavity. The supra-condylar fossae of opposite sides are not very large nor deep. Measurements of humerus and ulna. Transverse diameter, distally 175 Anteroposterior diameter of inner condyle 104 Anteroposterior diameter of outer condyle 125 Transverse diameter, olecranon 110 The portion of ulna just measured belongs to a young individual found near to the one above described as Eobasileus furcatus. It is represented on Plate XXIX, Fig. 7. Belations. — Besides the difference in the development of the anterior nasal tuberosities, which might be sexual only, this species differs from L. cornutus in the simple naso-maxillary horn-cores, which want the interior tuberosity of that species, and ia the fact that they are composed exclu- sively on their inner sides of the nasal bones to the apex, the maxillaries forming the outer face. JE. pressicornis has also a much wider and less massive parieto-occipital basin, with lighter horn-cores. Minor differences have been already mentioned. DINOCERATA. 569 Restoration. — As in all the species of Uintatheriutn in which the horns are known, these appendages stood in front of the orbits, it is probable that such was the case in the Eobasileus furcatus also. The muzzle is mate- rially shorter and more contracted, and the true apex of the muzzle was not overhung by the great cornices seen in LoxoJophodon cornutiis. The occipital and parietal crests are much more extended in this species than in the L cornutiis, so that in life the snout and muzzle had not such a pre- ponderance of proportion as in that species. All the species of this genus were rather rhinocerotic in the proportions of the head, although the liorns and tusks produced a very different physiognomy. Tlie extremities of the nasal bones are strongly pitted and exostosed, and this, taken in connection with the elevation of the head, renders it probable that this species pos- sessed a proboscis of less or greater length. History. — This species was originally described by the writer in a short papei', which was published and distributed August 19, 1872, under the generic name Loxolophodon. I shortly afterward referred it to tlie new genus Eobasileus. LOXOLOPHODON Cope. Proceed. Amer. Philos. Soc, If-TS, p. C80, extra copies published August 19th, aud p. 488 (August 22d). AuDual Report U. S. Geol. Surv. Terrs., ld"2 (1S73), p. 565. f Tinoceras, Marsh, American Jour- nal of Science aud Arts, 187'2 (October), published September yist. The cranium in this genus is elongated and compressed. The muzzle is posteriorly roof-shaped, but is anteriorly concave and flattened out into a bilobed protuberance which rises above the extremity of the nasal bone. This extremity is subconic and short and decurved. A second pair of horn- cores stands above the orbits, each one composed externally of the maxil- lary bone, aud internally of an upward extension of the posterior part of the nasal. Behind this horn the superior margin of the temporal fossa sinks, but rises again at its posterior portion, ascending above the level of the middle of the parietal bones. This portion of the skull is injured in my onl]^ specimen. The occipital rises in a wall upwards from the foramen magnum, and supports, probably, a little in front of the junction with the superior and inferior ridges bounding the temporal fossa, a third horn -core on each side. The base of this core is as stout as that above the orbit, and subround in section. The temporal fossa has its principal extent poste- 570 THE BRIDGER EPOCH. rior to the zygomatic arch, and is in form like a trough, the inferior edge being recurved from the squamosal process to the summit of the occipital crest. It is narrow within the zygomatic arch, which is short, inclosing a space whose length is less than one-fourth that of the cranium. The occipital bone extends but a short distance on each side of the condyles, and is separated from the mastoid by an irregular suture, which is pierced by a large mastoid foramen. On the inferior face, near to each condyle, and one-third the distance from its inner extremity, is a posterior condyloid foramen, isolated by a narrow bar from the extremity of the foramen lacerum posterius. The paroccipital process is represented by a small tuberosity, and the mastoid by a rather larger one, some distance anterior to it. The meatus auditorius opens upward just below the external ridge of the temporal fossa, and at a little distance behind the post-glenoid process. Its canal contracts rapidly, and extends upward and backward toward the labyrinth. It is separated from the foramen lacerum by but a thin wall, and if there was an expansion of the cavum tympani it must have been exceedingly small, owing to the close approximation of the mastoid to the basi-occipital and sphenoid at this point. The labyrinth is lodged in a petrous mass opposite the occipito-mastoid suture, and the canals are small. The basioccipital contracts anteriorly, and with the sphenoid forms an uninterrupted boundary of the foramen lacerum This terminates opposite to the posterior boundary of the external meatus, and gives rise to a wide, shallow groove, which extends anteriorly between the pterygoid ala and the post-glenoid process, and, turning outward round the latter, grooves it. Opposite to the post-glenoid process and just posterior to the end of the pterygoid, a foramen enters, which, though remarkably small, is the fora- men ovale. Almost continuous with it is a canal which pierces the base of the pterygoid longitudinally, and issues in an excavation of its external face near the sphenoid. This is the alisphenoid canal. There appears to be no foramen posfglenoidale, but there is one in the position of the stylomastoid on the inferior side of the mastoid bone and posterior to the meatal groove. The pterygoids are remarkable for their great length, inclosing, as they DINOCERATA. 571 do, with the palatine process, a deep, narrow, trench like fossa, which measures almost the entire length of the zygomatic fossae. Processes of the sphenoid contribute to these walls (which are thus double), and the sphenoid roof is strongl}' concave. The alisphenoid is elongate antero-posteriorly, and is principally in contact superiorly with the frontal; anteriorly it has a short suture with the lachrymal. I cannot determine whether the orbito- sphenoid is distinct. Almost its entire length is traversed by a shallow groove, which terminates in a small foramen opticnm, opposite to a point marking the posterior third of the zygomatic fossa. The foramen rotun- dum issues as usual between the alisphenoid and the pterygoid, within the alisphenoid canal, which exceeds it in diameter. The lachrymal is a large bone, of a triangular outline, the shorter side being inferior. It is entirely on the inner face of the orbit, and, as in the elephant, separates the frontal and maxillary by its superior prolongation. Its inferior border is slightly notched in front by the large foramen infraor- bitale posferius, and the anterior is deeply emarginate, passing behind the small/ lachrymale. The palate is remarkable for its length and narrowness. Its roof is chiefly composed of the maxillaries, but a very short portion is formed by the palatine plates of the o.- o. palatina. These are pi'oduced into a median point behind between the nares, and exteriorly form the inner wall of the postnareal trough for a considerable distance. The maxillaries also form the outer wall for a short distance, being produced in a contracted form behind the molar teeth. The two bones inclose a small foramen in this prolongation, and a larger one on the anterior suture of the palatine, the foramen palatinum. The palate is deeply concave anteriorly. There is an elongate foramen close to the alveolus of the first premolar, extending anterior to it. The premaxillaries are longitudinal and separated anteriorly, for two-fifths of their length, by a large foramen incisivum, which they do not inclose in front. They extend on the side of the muzzle into an acute angle upward and backward, and are prolonged forward above the exterior nares, which the suture reaches by an abrupt descent. The maxillar}^ sup- ports the malar on a posteriorly directed process which reaches to the end of the antei'ior third of the arch below, half that distance on the side, and 572 THE BRIDGER EPOCH. is bordered by a narrow strip of the malar on the inner side, as far as the anterior boundary of the orbit. The dentition is I. 0 ; C. 1 ; Pm. 3 ; M. 3. The canine is a tusk of compressed form, witli anterior and posterior cutting edges, and a strong posterior curvature. Its fang is embraced one-third by the pi-emaxillary bone, and is inclosed in a rib-like swelling of the sides of the cranium, which extends upward and backward. The premolars have transverse cor- date surfaces of attrition. These have probably resulted from the wearing down of a chevron of two crests converging inward, in some with an inner tubercle. On the molars this crescent is represented by a V, with the apex inward ; on the last, the inner tubercle is at one side (the posterior) of the apex Name. — I first applied the name Loxohphodon, with a diagnostic descrip- tion, to this genus, in a short paper published August 19, 1872, as above cited. The L. cornutus was there cited as the first species, and is here retained as the type. I again described it more fully in a paper published August 22d, citing Eobasileus (August 20th) as a synonym, in which I was in error, as indicated in the present book. The same nomenclature was employed in a paper read before the American Association for the Advancement of Science, held at Dubuque, commencing Augusl 23, 1872. Prior to the issue of the paper of August 22, 1 had (February 16, 1872) provisionally applied the name Loxolophodon to the species there called Bath- modon semicinctus Cope, without generic character. With further material it appears that the Bathmodon semicinctus is very near to the B. radians, so that the name Loxohpliodon was cancelled in this connection, and was used again for the present genus without interference, especially as it was first published as a nom^n nudum. Pi'ofessor Marsh, in the American Journal of Science and Arts, 1872 (September 21),* applied the name Tinoceras to a species {T. grandis) which he has led us to infer belongs to this genus, but did not specify the generic characters. He had previously applied it without description to the Uinta- therium anceps, August 24 (and 19,t in an erratum, where Mastodon anceps * I did not receive this, and most of the other papers of Professor Marsh on this fauna, till early in December, 1872. t These papers were not received by me till early m December, 1872. DINOCERATA. 573 is altered into Tinoceras anceps). As no characters whatever were assigned to it on either of these occasions, it had no value in zoological nomencla- ture Three species of this genus are known to me, the L. cornutiis and the L. gakatus, which are represented in my collection, and the L. spkrianus, which is founded on a skull preserved in the museum of Princeton Uni- versity, New Jersey. The last named was as lai'ge an animal as the two others, and had a very elongate skull with weak horns and narrow, high occiput. Its median horns are situated .well anterior to the orbit, and its zygomatic fossa is remarkably small. It was discovered by the Princeton scientific exploring party at the same locality that produced the other species, viz., the Mammoth Buttes of Western Wyoming. The three species may be distinguished as follows : Median horns triangular in section, with internal tuberosity, and above orbits ; occiput narrow L. cornutus. Median horns subquadrate in section without internal tuberosity; occi- put and nasal tubercles wide L. galeatus. Median horns subround and without tuberosity, in front of orbits; occi- put and nasal tubercles nai row L. spierianus. Messrs. Scott, Spier, and Osborne, of Princeton, have published a description* of the lower jaw and teeth of a species of Loxolopliodon, which they identify with the L. cornutus, which was derived from the locality and horizon of the species above mentioned. They show that the descending flange of Uintatherium and Bathyopsis is only represented by a convex ridge on each side of the symphysis. They point out the characters of the denti- tion, which are remarkable. The molars much resemble those of Bathyop- sis. The canines and incisors are alike in form, and in a continuous series. The crowns are compressed so as to be extended anteroposteriorly, and ai-e deeply emarginate, so as to be bilobed, the lobes with subacute edges. This form of incisors is unique, resembling only remotely the large median incisors of certain Insectivora. Eesemblance to mammals of the same type may be traced in the molar teeth. " American Journal of Science aud Arts, xvii, 1879, p. 304. See review of this paper in American Naturalist, 1879, p. 334, where some corrections are made by the writer. 574 THE BEIDGER EPOCH. LOXOLOPHODON CORNUTUS Cope. Loxolophodon cornutus Cope. Proceed. Amer. Philos. Soc, 1872, p. 580 (August 19); 1. c, 1872, p. 483 (August 22). EobasileuB cornutus Cope, Amer. Nat., 1872, p. 774. Annual Report U. S. Geol. Surv. Terrs., F. V. Hayden, 1872 (1873) p. 568, Plates I-IV. ?f Tinoceras grandia Marsh, Amer, Joum. of Sci. and Arts, October, 1872 (published September 2l),/de Marsh. Plates sxxvii to xlii. Established on the remains of a single individual, which consist of a nearly perfect cranium, the right scapula complete, several vertebrae, includ- ing the sacral, the first or second rib, the pelvis complete, and the entire right femur ; also probably the proximal end of a radius. The species is remarkable for the narrow form of the cranium, its width at the middle being one-fourth its length. A little in front of the middle are situated the horn-cores. These diverge, the upper portion having an outward curvature The base of each is triangular, with obtuse angles in section, and the inner angle is the section of a rib-like projection which commences half way up the horncore and extends across the middle line to its fellow. Above its rather abrupt termination the core is transversely com- pressed, with oval obtuse apex. The core measures M. .240 (9.5 inches) from its base in front, M. .108 (4.25 inches) in width at the base behind, and .077 (3 inches) in diameter at the apex. A slight swelling of the sides of the muzzle descends obliquely forward from the base of each horn, which enlarges below into a jjrominent rib, which incloses the alveolus of the canine tusk. In front of the horns the muzzle is roof-like ; anteriorly it flattens out, and swells a little above the posterior end of the nasal meatus. In front of this it expands again, and rises gently to the extremity of the bilobed nasal shovel, which overhangs the premaxillaries, the nasal meatus, and the greater part of the apex of the nasal bones. The latter is short and with a wide base, and resembles two lateral cones flattened together, their extremities obliquely truncate outward and excavated. In the nasal bones of the Eohasileus furcatus Cope, the shovel is represented by a tubercle only on the side of a continuous surface. The composition of the upper surface of the cranium is somewhat difficult to determine, owing to the injured state of the posterior part. If we regard the bone which bounds the lachrymal behind and above, as frontal, as I did in originally describing the species, it gives an extraordinary extent to the DINOCEEATA. 575 nasals, for the common suture of these bones extends V-shaped back- ward, to a point opposite to the middle of the zygomatic arches. It gives to the nasals an extent equal to that of the frontals and parietals combined. They not only support the anterior shovels, but form the inner half of the median horn-cores, rising as high as the tuberosity above described. The immense length of the snout in Loxolophodon looks as though the nasal bones had extended themselves forward, so as to ossify the basal portions of an elephantine proboscis. The frontals descend behind the horns, with a very obtuse or rounded continuation, to the inner side of the fossa, and without any superciliary margin. They form with the posterior part of the nasals a shallow median basin. The suture with the parietals is very indistinct, but if I have truly discovered it, it forms another posteriorly directed chevron, and leaves but a narrow superciliary portion of the frontals. Above the postglenoid pro- cesses the parietals rise again to the transverse occipital crest, but to what height is uncertain. At the mastoid region, the cranium widens a little, and is excavated at the sides by the temporal fossae. Near where the lateral and supraoccipital crests join the inferior ridge-like border of the temporal fossa, which position is occupied by a knob in E. furcatus, is a strong horn- core with subcylindric base. It stands obliquely backward toward the junction of the posterior squamosal and transverse crests, and is connected to these by an oblique ridge, one side of which is marked with irregular, short, longitudinal rugosities. At the base of these elevations are three sinuses. This portion was found close to the skull, but separated from it, and the loss of intervening fragments prevents actual fit. The occiput is preserved for four inches above the condyles ; it doubtless displayed a posteriorly sloping transverse crest as in U. furcatus. The paroccipital and mastoid tuberosities are narrowed and extend obliquely downward and forward. The lower part of the exoccipital suture runs along a ridge, and there is a tuberosity in front of the mastoid foramen. An irregular ^-shaped crest extends upward with the apex at the inferior temporal crest, and its anterior limb forms part of the poste- rior boundary of the meatus auditorius. The inferior temporal crest is directed outward below, but forward above. 576 THE BEIDGER EPOCH. The narrowness of the cranium is readily seen on comparing the post- glenoid processes. These are strong, and have considerable transverse extent, and are separated by a space only a little greater than the trans- verse diameter of each. A strong groove passes along the inner base of the postglenoid process to the foramen lacerum. It is overhung by a promi- nent horizontal ridge of the postglenoid. The zygomatic arches are com- pressed posteriorly, with crest-like superior ridge, but rounded above ante- riorly. There is not the least trace of posterior boundary of the orbit. The squamosal process overlaps the malar bone extensively, terminating in a point, which ends obtusely. The malar is supported in front by a maxillary process, which is united with it by a zigzag suture on the outer face, and a squamosal one within and below. The foramen infraorhitale exterius is large, and issues a short distance in front of the orbit, not so near it as in the elephants. From this point to the ridge inclosing the canine alveolus the side of the maxillary bone is deeply concave, and the palatal surface con-e- spondingly contracted. The bone is continued upward and outward as the external part and apex of the middle horn-cores. Anteriorly it is bounded by the premaxillary to a point as far anterior to the base of the horn as the width of the latter; behind that point it is in contact with the nasals. The premaxillary is prolonged upward and backward into a narrow tongue. Its inferior portion is convex above on each side, concave below, with project- ing alveolar borders, which are flat and slightly concave fore and aft. The extremity of each is rugose below, supports a prominent tubercle medially and a smaller one at the superior angle. The exterior nares are not separated by osseous septum. Their lateral border is marked on the inferior surface of the nasal and pi-emaxillary roof by a curved ridge or crest, which converges forward and bounds the interior concavity of the roof. This gave support to muscular or ligamen- tous attachments. The posterior angle of the nares is abruptly excavated, and with thickened walls. The palate is remarkably narrow, and is most deeply excavated between the alveoli of the tusks, or at the maxillo-pre- maxillary suture. From near this point to the palatine suture a low but sharp crest extends along the middle line. The width of the palate at the diastema is one-ninth of its length. The diastema is more than half the DINOCERATA. 577 length of the molar series. The pterygoid process of the palate has two convergent grooves on its inferior surface. The alisphenoid canal is larger, exceeding in diameter both the foramen rotundiim and / ovale. The vomer does not unite with tlie superior crest of the palatine bones. The sphenoid flattens out behind the postnareal trough and is co-ossified with the basioccipital. The latter is marked by two oval surfaces at the place of suture, with a slight prominence between. No lower jaw was found with this specimen, but from the contraction of the parts opposed to it, it was evidently very small. The teeth are remarkable for the extent of the exposure of their slender roots, as well as their very small size as compared with the size of the animal. The tusk is .slightly turned outward at the tip and the inner face is worn by attrition with some opposing tooth for one-third its length on the posterior third. Tiie superior margin of the enamel on this side is chevron-shaped, the apex being only one-third the length from the extrem- ity. It extends further upward in front and on the outer side, but is worn in an oval patch at the apex of the chevron of this side by contact with the inferior teeth, as above described. The enamel is smooth behind, rugose in front. The crown contracts regularly to a flattened obtuse apex. The fang is hollow for about half its length. The enamel of the molars is nearly smooth. Each one has a strong cingulum fore and aft, which is discon- tinued on the inner and outer faces except in Pm. 1 and M. 2. In the former it is continued on the outer side at the base of the concavity of the exterior face; on the lattei', it is continued round the inner side. The grinding surface of the Pm. 1 is tripodal, and probably composed of a worn crescent and inner tubercle. The others are transverse arrow-shaped; the worn M. I. indicates mature age. M. II. is larger than M III. Its oblique crests have evidently been worn from before. All the molars have three roots, but the posterior pair are united for part of their length in all. Cranial measurements. Length from end nasals to end occipital condyle (3 feet 1.5 inches) 930 Width jnst behind end nasal shovels 192 Width in front of horns 132 Width at base of horns in front 205 Width behind horns at apex of frontal suture 185 33 C 578 THE BRroGER EPOCH. M. Width above posterior edge meatus auditorium 310 Width between apices middle horn-cores 370 Width of basis of supraoccipital horn-core 100 Width including zygomatic arches (greatest) 320 Length of nasal bones to ridge between horn-cores 410 Length of nasal bones to frontal suture 540 Length of zygomatic fossa above 230 Length from angle nares to end of shovel 206 Length from angle nares to end of premaxillary 155 Length from end of premaxillary to basis of canine .120 Length from end of premaxillary to basis of Pm. 1 276 Length of molar series 185 Length of palate - 450 Length of pterygo-palatine crest 200 Length of sphenoid axis 185 Length of basioccipital (with condyles) 128 Width between tips of premaxillaries 070 Width at canine alveoli 185 Width between canine alveoli 080 Width at diastema 050 Width between last molars 070 Width between pterygo-palatine crests 065 Width of post-glenoid process 095 Width between post-glenoid processes — 095 Width of basioccipital at front 073 Width of basioccipital at condyles 200 Width of space for tympanic chamber 034 Xength of tusk on curve (12.7 inches) . 320 Diameter at middle (anteroposterior) .050 Diameter at base (anteroposterior) 063 Diameter at middle (transverse) .030 Diameter of crown of Pm. 1 transverse 022 Diameter of crown of Pm. 1 anteroposterior 024 Diameter of crown of M. 2 anteroposterior 035 Diameter of crown of M. 2 transverse 034 Diameter of crown of M. 3 transverse 043 Diameter of crown of M. 3 anteroposterior 045 Elevation of shovel above base of apex of nasal 060 The measurements may require some correction in respect to the supra- orbital width, where the cranial walls have suffered from compression. The frontal of one side has been pushed so as to overlap that of the other by about an inch. The scapula is of a sub-triangular form, the front being vertical, the apex directed backward and an angle upward. The posterior expansion is considerable, as in the elephants, while the superior angle is acuminate and much produced and massive. The spine is much elevated, bounding a deep supraspinous fossa. It is truncate proximally, descending to near the border of the glenoid cavity. Its extremity is dilated in alate fashion, DINOCERATA. 579 equally fore and aft, and not posteriorly only as in the elephants. The glenoid cavity is flattened so as to be longitudinal, and the coracoid is a rudimental tuberosity. Measurements of scapula. Total length (25.25 inches) 640 Total width 480 Length of apex from spine 140 Elevation of spine proximally 125 Length of glenoid cavity 185 Width of glenoid cavity 110 The interior side of the scapula is strongly convex by the develop- ment of two longitudinal ribs, one corresponding to each foesa, but concave in longitudinal section. The proximal end of the radius exhibits two facets oblique to each other, the larger concave and transverse, the other oblique downward. Transverse width M. 0.130; vertical .070. The extremity of a humerus not found with this individual, to which the radius appHes pretty well, has a very oblique trochlear face, and measures seven inches across the con- dyles. It, however, belongs to a smaller species. The femur is entire. Like that of other species of the group it is much expanded proximally and deep distally, with the shaft contracted and some- what flattened in the plane of the great trochanter. The latter is in one plane, with its external margin turned a Httle backwards. The head is part of a globe, and is a little more elevated than the trochanter, and separated from its apex by a shallow concavity. There is no little trochanter. The rotular face is not elevated nor wide, and with lateral borders subequally developed. The anteroposterior axis of the condyles is somewhat oblique to a line at right angles to the proximal end. This is because the interior condyle is the longer; its articular face is continuous with the rotular, with a marginal notch; the outer condyle is continuous with continuous outer margin. Strong ridges revolve from above the condyles to the pos- terior face of the shaft, the inner near the condyle. The outer runs parallel to the main axis as a low external ala, and backwards three inches above the condyle. The face between them is concave. 580 THE BEIDGER EPOCH. Measurements of femur. Total length (31.75 inches) 747 Total proximal width 255 Diameter of ball 136 Transverse diameter at middle of shaft 096- Anteroposterior diameter at middle of shaft .' 074 Anteroposterior diameter of condyles posteriorly 150 Transverse diameter of condyles posteriorly 160 Transverse diameter of condyles distally 145 The pelvis has a large transverse expansion. The ihac plates are ovoid in outline, with the apex outward and downward. The margins are rather thin, excepting the internal above the acetabulum. These are massive, and with a longitudinal excavation. They terminate in a deep oblique excava- tion for the diapophyses of the sacrum. The external margin rises com- pressed from just above the acetabulum. The latter is large for the size of the ilia, and its margins rise to a slight elevation beneath the exterior mar- gins of the latter. The incisura acetabuli is obclavate and nearly sym- metrical. The OS ischium is compressed and deeper than the pubis. It pos- sesses a tuberosity on the posterior inferior margin. The obturator foramen is small, and is a vertical oval. The pubis is rather slender and shoi't. Its section at base is subtriangular; beyond, it becomes more compressed, and is spirally twisted on itself through a part of a circle. Its anterior margin near the symphysis is strongly rugose for the origin of the pedineus muscle; which rugosity extends into a band on the outside of its proximal portion. Measurements of pelvis. M. Long diameter of ilium 605 Transverse diameter at acetabulum 430 Length of inferior free margin at acetabulum , 250 Long diameter at acetabulum 150 Shorter diameter at acetabulum 130 Shorter diameter at obturator foramen 070 Width of ischium at tuberosity 140 Length of ischium at tuberosity 110 Diameter of pubis at obturator foramen 062 Expanse of ilia laid on a flat surface and with sacrum in place (4.2 feet) 1. 280 The general character of the pelvis is more like that of the elephant than that of any Perissodactyle. It agrees with the former and differs from that of the rhinoceros in the shortness of the pedestals of the ilia or rather in the sessile position of the latter on the acetabula; also in the absence of DINOCERATA. 581 production of the iliac crests in advance of and above the sacrum. It is also elephantine in the shortness of the inferior elements of the pelvis. Of vertebrce there are preserved a dorsal, two lumbar, and some sacral. The first is very short and transverse. It is so injured that I can only give some measurements. The base of the transverse neurapophysis is a flat oval; both capitular articular surfaces are deep. The anterior lumbar is longer, but still short ; its ai'ticular faces are slightly concave. The neural arch is wide and supports the diapophysis. The sides of the centrum are concave and pierced by foramina, and there is a strong rugo^ hypapophysis. The sec- tion at the middle is subtriangular. I have three sacral vertebrae, which are separated by very distinct sutures. They diminish very rapidly in si2;e, and the centra become flattened-transverse. It is doubtful whether there was a fourth vertebra, and the tail must have been short and slender. The articular face of the first is a transverse, rather broad ellipse, and twice the diameter of the third distally. The diapophysis of the second is much the stoutest. It unites with the subvertical plate-like diapophysis of the first as well as with that of the third. It is concave above, and terminates dis- tally in a massive L-shaped surface of articulation with the ilium. The foramina inclosed by the diapophyses are quite large. The inferior face of the first sacral centrum is slightly concave with a hypapophysial tuberosity in front; it is strongly concave in the second. Measurements of vertebrce. M. Anteroposterior diameter of dorsal 044 Diameter at bottom neural arch of dorsal 040 X.ength of base of neurapophysis 041 Diameter of centrum lumbar (vertical) 090 Diameter of centrum lumbar (transverse) 110 Diameter of centrum lumbar (anteroposterior) 060 Length of three sacral vertebrae 226 Transverse extent of sacrum ( 15 Inches) 380 Diameter of first vertebra at free end (transverse) (4.6 inches) 122 Diameter of first vertebra at free end (vertical) 093 Diameter of last vertebra at free end (vertical) 021 Diameter of last vertebra at free end (transverse) 06.5 Total expanse of heads of rib 106 Diameter of capitular face ( vertical) 048 Diameter of tubercular (vertical) 030 Width of rib just below head 050 Restoration. — We may ascribe to the Loxolopliodon cornutus form and proportions of body similar to those of the elephant. The limbs, however, 582 THE BEIDGER EPOCH. were somewhat shorter, as tlie femur is stouter for Its length than in the E. indieus. It was intermediate in this respect between the latter species and the species of Bhinocerus. The tibia is relatively still shorter. The tail was quite small. The neck was a little longer than in the elephants, but much less than in the rhinoceroses ; the occipital crest gave attach- ments to the ligamentum nuchce and muscles of the neck, which must needs have been powerful to support the long muzzle with its osseous prominences, and to handle with effect the terrible laniary tusks. The head must have been supported somewhat obliquely downward, present- ing the horns somewhat forward as well as upward. The third or posterior pair of horns towered above the middle ones, extending vertically with a divergence, when the head was at rest. The posterior and middle pair of horns were no doubt covered by integument in some shape, but whether dermal or corneous is uncertain. Their penetrating foramina are smaller than in the Bovidce. The cores have remotely the form of those of the Antilocapra americana, whence I suspect that the horns had an inner process, or angle as in the prong-horn at present inhabiting the same region. The nasal shovels may have supported a pair of flat divergent dermal tuberosities, but this is uncei'tain ; they are not very rugose. The elevation of the animal at the rump was about six feet, distributed as follows, allowance being made for the obliquity of the foot. Inches. Foot 4.50 Tibia 20.50 Femur 31.75 Pelvis 16.00 72.75 The anterior limbs were stouter than the posterior, judging from the proportions in various species, and were no doubt longer if of the Probos- cidian character. This would give us the • hypothetical elevation at the withers : Inches. Leg 61.00 Scapula (actual) 21.00 Neural spines (extremities) 7.00 Or 7 feet 5 inches 89.00 DINOCERATA. 583 These measurements ax'e made from the plantar and palmar surfaces, allowance being made for the pads. The obliquity of the anteroposterior axis of the anterior dorsal vertebra indicates that the head was posteriorly elevated above the axis of the dorsal vertebrae. Owing to the lack of cervical vertebrae, the length of the neck cannot be determined. It may have been short, as in the JEohasileus furca- tus, or longer as in the species of Uintatherium. In the former case it is entirely clear that the muzzle of this animal could not have reached the ground by several feet, and that, as occurs in the similar cases of the tapirs and elephants, there was a proboscis to supply that necessity. The indi- cations derived from the bones of the muzzle point to the attachment of a proboscis or a heavj^ upper lip, and the ridges of the symphysis of the lower jaw, pointed out by the Princeton paleontologists, suggest a strong prehensile lower lip. The fact that the foramen infraorhitale of the Loxolop- hodon is less than in the elephants, in no wise militates against the posses- sion of a proboscis, for it is still smaller in the tapir, which has one, and larger in many rodents which are withoiit it. The numerous rugosities of the posttympanic and mastoid regions indicate the insertions of strong mus- cles. Some of these may have adductors of large external ears. The inferior incisor teeth have no adaptation for cutting oflP vegetation. The mental foramen is small, but the small nutrient artery thus indicated is not adverse to belief in a prehensile under lip to make up for the use- lessness of the teetli. The projecting nasal regions would prevent short lips from touching the ground. The posterior position of the molar teeth indicates use for a long, slender tongue. This species was probably quite as large as the Indian elephant, for the individual described is not adult, as indicated by the freedom of the epiphyses of the lumbar vertebrae, and fragments of others in my posses- sion indicate considerably larger size. Habits. — The very weak dentition indicates soft food, no doubt of a vegetable character, of what particular kind it is not easy to divine. The long canines were no doubt for defense chiefly, and may have been useful in pulling and cutting vines and branches of the forest. The horns fur- nished formidable weapons of defense. That the anterior nasal pair were 584 THE BEIDGEE EPOCH. DINOCERATA. 585 not used for rooting in the earth is evident from the elevation of the head, Avhich would render this impossible. This huge animal must have been of defective vision, for the orbits have no distinctive outline, and the eyes were so overhung by the horns and cranial walls as to have been able to see but little upward. The muz- zle and cranial crests have obstructed the view both forward and backward, so that this beast probably resembled the rhinoceros in the ease with which it might have been avoided when in pursuit. Synonymy. — According to Marsh, he described this species September 21, 1872, under the name of Tinoceras grandis, which thus becomes a syn- onym of Loxolopliodon cornutus. As the name Tinoceras had never been described prior to that date, although applied to the Titanotherium (?) anceps Marsh, previously without description, this name becomes a synonym of Loxolopliodon. Locality. — The remains of the Loxolopliodon cormitus were found together by the writer in August, 1872, in a ravine of the bad lands of Wyoming. The greater part of the cranium and the femur were excavated from the base of a cliff of perhaps 250 feet in height, on the side of a ravine elevated about 1,000 feet, in the Mammoth Buttes, on South Bitter Creek. As the basin of Bitter Creek is 7,500 feet above the sea, the fossil was taken from an elevation of 8,500 feet. The horizon is the Washakie Group of the Eocene, of Hayden. ^ An account of the remarkable locality in which I found the specimen was published in the Penn Monthly Magazine for August, 1873. LOXOLOPHODON GALEATUS Cope. Hobasileus galeatua Cojie, Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 456, pi. i. Paleonto- logical Bulletin No. 17, p. 1, October 25, 1873. Plates xliii, xliv. Represented by the upper portion of a cranium of an individual of the size of the Loxolojihodon cormitus. The maxillary, palatal and basi- cranial regions and teeth ai-e wanting, and there is no lower jaw. The species possesses a greatly elevated occipital crest, whose superior border presents a median angle upward. A short distance in front of it, and connected by a very stout, lateral ridge, there arises, on each side, 586 THE BEIDGEE EPOCH. a large, erect horn-core. The base is very massive, subquadrate in section, and flattened in front. Posteriorly, it presents a very shallow groove, which is bounded on the outside by a low ridge. The shaft expands gradually, and is proportionally flattened from behind forward. The posterior face is flat; the anterior gently convex. The extremity is trans- verse-convex, and pitted for cartilaginous or corneous attachment. These horns stand on the parietal bones The frontals extend to their bases, and send a laminar expansion backward to the margins of the lateral and posterior crests, covering the parietal in the fundus of the basin, which the former inclose. The median horns are very stout, and are connected with the posterior by an acute supratemporal ridge. Their inner face is composed to near the apex, of the nasal bones. Where they terminate, the apex contracts, and is composed of a cylindric production from the maxillary. The section of these cores at the middle is subquadrangular, and longitwdinally oval at the base. The extremity of the nasal bones is small and contracted, and is ex- tensively overhung by the cornice-like, flat cores above them. Thias the end of the snout has a bilobate outline when viewed from above. The occipital face is concave in vertical section, and presents a V- shaped depression, witlv the angle downward, and a low ridge on the mid- dle line to the transverse superior border. Measurements. u. Width of the foramen magnum and occipital condyles 2100 Elevation of occiput (8 inches) 2500 Width of basin between lateral crests 3250 Height of posterior horn-core (7 inches) 2300 Width of base of posterior horn-core anteroposteriorly 1300 Width of base of posterior horn-core transversely 0900 Width at summit 1230 Height of median horn-core 1750 Diameter of base anteroposteriorly 1000 Diameter of base transversely 0800 Diameter of summit 0650 Projection of nasal cornices beyond apex 0630 Length of posterior molar, crown 0450 Width of posterior molar, crown 0550 This species is equal in size to the largest known from the Bridger formation. It diff'ers from Loxolophodon cornutus in the posteriorly-truncate DINOCERATA. 587 base of the posterior horn-cores, the quadrate instead of triangular section of the median cores, their greater stoutness, their lack of internal angle, and the extent of their inner face covered by the nasal bones. It more nearly resembles the E. f meatus Cope, and may possibly prove to repre- sent an old male of that animal. There is, however, a considerable dis- parity in their sizes; and the horns of L. galeatus differ in the greater stout- ness, having twice the diameter, Avith little greater height. They differ also in form, in the abrupt contraction just below the apex. The cornice- like cores of the nasal bones represent the tubercles of the E. pressicornis. The posterior horns differ in many ways from those of the E. furcatus, and are probably sufficient to indicate a different species. From the bad lands of South Bitter Creek, or the Mammoth Buttes, of Southwestern Wyoming; the Washakie Basin. UINTATHERIUM Leidy. Proceed. Acad. Nat. Sci. Phila., 1872, p. 169 (published August 1). Uintamastix Leidy, loc. cit. : f Dino- ceraa Marsh, Amer. Journ. Sci. Arts, 1672, October, 1872 (published September 27). This genus resembles Eohasileus in its general proportions, but differs in its more elongate cervical verterbrse. The centra of these are flat at both extremities, but have not such a marked elephantine abbreviation as seen in the genus named. This enabled the head to approach the ground more nearl}^, and as the limbs were shorter in some of the species, they no doubt modified the length of the muzzle and lips. Several names have been applied to this genus. Professor Leidy's name, here employed, bears date early in August. Under date of Septem- ber 27, Professor Marsh proposed the name Dinoceras (Amer. Journ. Sci. Arts, 1872) for the U. mirabile, but did not give his reasons for separating it from his inoceras (the names of the two bear an objectionable resem- blance), or those published by Dr. Leidy or myself As it is propably synonymous with Uintatherium, I include it here, as is done b}^ Dr. Leidy. I am acquainted, by autopsy, with two species of this genus. None of them are so large as the Eohasileus pressicornis. U. rohustum Leidy, is Bmaller, and the U. lacustre Marsh, smaller still. U. mirdbile {Dinoceras) 588 THE BRIDGER EPOCH. Marsh, is about the size of the U. rohustum, but differs from it in the absence of a tubercle on the last molar. I therefore retain three species, as follows: Uintatherium robustmn Leidy, (J. mirahile Marsh, TJ. lacustre Marsh. For convenience I compare these species with those of Eohasileus. The naso-maxillary horn-cores have been seen in E. furcatus and U. mirahile, and the nasal tubercles in the same. The posterior horn-cores ^re known in the U. mirabile. The posterior and lateral crests of the cranium inclose a basin-shaped concavity above in all these speeies. It has been observed in all but E. pressicornis. The dentition is similar to that in Loxohphodon, i. e., I. 0; C. 1; Pm. 3; M. 3. The first premolar in U. lacustre has an internal cone and outer concave crest. The worn surfaces of the other teeth in that species, U. rohustum and U. mirahile, are nan-ow ovate, with a deep exterior emargination. The true molars support two crests, which converge inward and unite with a small tubercle behind the apex in U. lacustre and U. rohustum. The tusk is long, compressed, and double-edged, as in Loxohphodon. The last inferior molar in U. rohustum possesses three transverse crests, the posterior two parallel, and obliquely directed inward toward the axis of the anterior, which is the highest. In a specimen of one of the smaller species the idna widens consider- ably distally, being nearly as wide as the much- expanded olecranon. The latter is large, flflttened, and subtransverse, and presents a sharp ridge internally. On the inner side of the distal part of the articular face for the humerus is a tubercle, from which a short, wide groove runs out on the inner face of the bone. The head of the radius is a little exterior to the middle line, and the shaft crosses the ulna in an open, shallow groove, to the inner side. The cuboid is flat, and displays two proximal and two distal articular facets in an undetermined species described below. The astragalus of the same species is subbifurcate posteriorly, and has internally an extensive oblique malleolar fossa. The calcaneum is short and massive, with two supe- rior and one small anterior articular facet. The species, including Eohasileus furcatus, may be thus distinguished : 1. Large species (occipital condyles extending over about M. 0.170.) Nasomaxillary horns long; posterior liorncores flat, elevated E. furcatus. DINOCERATA. 589 2. Species of intermediate size. Molars smaller, with an additional tubercle on the last U. robustum. Last molar without additional tubercle; maxillary horn-cores low, triangular; posterior horn-cores short, triangular in sec- tion (Marsh) U. miraUle. 3. Smallest species (occipital condyles extending over about M. 0.95). Molar teeth larger, the last with a posterior exijansion U. lacustre. UlNTATHEEIbM KOBUSTUM, Leidy. Proceed. Acad. Nat. Sci., Phila., 1872, p. 109, August. Report U. S. Geol. Surv. Terrs., i, pp. 96, 333, pi. XXV, tigs. G-l"2; iil. xxvi, figs. 1-3; pi. xxvii, figs. 30-34. Vintamastix atrox, Leidy, /. c. I have been able to examine, through the kindness of Professor Leidy, the type of his description, and find it to belong to a smaller species than any of those above described. The lateral-parietal and supra-occipital crests are well developed, and the lattQr extends obliquel}^ backward. Sev- eral peculiarities are to be observed in the dentition. Thus there is a great inequality in the height of the transverse crests of the posterior upper molar, the anterior, or the arched one, rising to a high cusp at its outer extremity. A small tubercle exists on the side of the inner angle of the grinding surface in the penultimate molar. The same angle is much ele- vated in an anterior molar. The canine is wider distally than in L. cornutus and less recurved. The mastoid process is quite prominent. The humerus has a prominent internal condyloid ridge and tuberosity, and the condyles are not very oblique. The inner posterior lobe of the tibial face of the astragalus is quite well defined. There is no median ligamentous pit on the trochlear face. Measurements (from Leidy). Inches. Depth of lower jaw at last molar 3.25 Length of humerus, about 21. 00 Diameter at condyles 7.50 I obtained a fragmentary lower jaw of this species from Henry's Fork of Green River in 1873 One ramus contains the roots of six posterior molars; the other sustains large portions of the crowns of the last two. The latter agree with the corresponding teeth as figured and described by Leidy. I have represented them on Plate XXXVI, Fig. 2. The sym- physis of this mandible is preserved, and is represented on Fig. 1 of the same plate. It is of singular form, being solidly coossified and very much compressed.' Its inferior middle line is an obtuse keel, which rises ante 590 THE BRIDGEE EPOCH. riorly with a regular curve. Its extremity is broken off in the specimen, but the deep alveoli of two incisors remain on each side. The form of these shows that the roots of the incisor teeth ai-e much compressed. A small mental foramen issues below the middle of the second or posterior one. This symphysis is a good deal more compressed than that of Loxo- lophodon cornutus, as described by Messrs. Scott, Spier, and Osborne, but has the same general character. I have given tiie following more detailed description of this specimen in the Proceedings of the Philadelphia Academy for 1882, p. 295. I had pre- viously mentioned it in the Annual Report of the Hayden Survey for 1872, p. 565. The presence of but two teeth on each side of the symphysis is an im- portant peculiarity, since the other species so far as described, are said to have four teeth on each side of the symphysis, viz: three incisors and one canine. Those present in the present species I suppose to be incisors. The molar teeth are so much like those of Uintatherium robustum, that I be- lieve the specimen to belong to that species. Symphysis very much compressed, so that the incisor teeth of oppo- site sides are close together; its inferior outline curved upwards to the alve- olar edge, in an obtuse keel. Base of flange for superior canine distinct, commencing below the posterior edge of the posterior alveolus, and imme- diately preceded by a mental foramen. Middle line of symphysis rugose. Ramus at last molar robust, owing to the prominence of the inferior part of the anterior masseteric ridge. In adaptation to the oblique position of the head, the inferior molars are oblique to the long axis of the ramus, slop- ing upwards and backwards, with exposed anterior roots. The molars in- crease in size posteriorly, and the last one is abruptly larger than the penul- timate. Their structure is as in U. robustum, i. e., with an obliquely trans- verse high crest in front, and a low posterior transverse edge of the heel, and a short oblique crest between the two. The last named is short, and is directed obliquely outwards and forwards towards the external exti-emity of the anterior crest, but disappears before reaching it. The internal extrem- ity of this and the low posterior crest, with the external extremity of the DINOCERATA. 591 anterior crest, rise into cusps. At the middle of the anterior base of the anterior transverse crest there is a tubercle, which represents the anterior limb of the anterior V in Coryphodon. Tlie crowns of the premolars are broken away in the specimen. The alveoli of the incisors are flat, and are directed forwards at an an- gle of only 20° from the horizontal until near their orifices, where the angle is greater. The roots of the incisors are thus curved upwards and forwards. There is but little space between the anterior alveolus and the anterior angle of the symphysis. Measurements. M. Length from anterior edge of symphysis to anterior base of canine flange 074 Width of symphysis below at bases of lateral flanges 032 Depth of symphysis between bases of lateral flanges 040 Width of symphysis above between posterior incisors 017 Length of bases of posterior five molars 148 Length of bases of true molars 110 Diameters crown, M.ii^'^"*"»P''«*''"°'^ O^^ < transverse in front 020 Diameters crown, m. iii | ^°*«''«'P°^t'="°' ^'^^ I transverse in front 025 Width of ramus at posterior edge of M. iii 040 Although the crowns are somewhat worn, the enamel is wrinkled in- termediately between coarse and fine. It may be remarked here that it is by no means certain that the other species here included under the head of Uintatherium have the number of incisors ascribed to the U. robustum. Ujntatheeium lacustee, Marsh. fDinoeeras lacustris, Marsh, I. c, October, 1872 (published September 27, 1872). Plate xxxvi, figs. 3-8. I have the occipital and parts of the parietal and squamasal bones, with some teeth of a specimen which I found together, and which I refer doubtfully to this species. Parts of the same cranium were sent to Pro- fessor Marsh by his collector, who left in the rock the fragments which I afterward procured. Professor Marsh's description of Dinoceras lacustris followed soon after, and his measurements agree with those of the speci- mens obtained by me. The species is distinguished from its congeners, apart from its smaller size, by the large size of teeth. These are nearly as large as those of Loxo- 592 THE BEIDGEE EPOCH. lopJiodon cornutus, and considerable larger than those of U. robustum and U. mirahile. The occipital condyles are not larger than those of the elk, Cervus canadensis. Their anterior inferior angles are separated by a triangular fossa of the basioccipital bone. This bone is expanded posteriorly, but naiTOws forwards, and is prominent and rib-like where it joins the basisphenoid. There is a short paroccipital process, which is anterior to the external part of the occipital condyle, its internal border rising from the condyloid foramen. Its anterior base, together with the other parts of the exoccipital bone, is closel}^ adherent to the posstympanic process, which forms with it a large trans- verse process behind the auricular meatus. The posttympanic element in this pi'ocess is much the larger, and projects further externally, where it presents a narrow edge. In this respect it differs much from the Loxolo- pJiodon cornutus and Eohasileus fiircatus, where the external face of this process is wide and otherwise characteristic (See plates XXXIII and XXXVII). The base of the postglenoid process is not so extended trans- versely as that of the posttympanic, and is well separated from it. Its out- line is that of one extremity of an ellipse. The glenoid surface has a con- siderable transverse extent in consequence of the sudden expansion of the zygoma behind. Its external extremity is marked by a low tuberosity. The aui'icular groove is bounded below inwai-ds from the internal base of the postglenoid process by an external extension of the os-petrosum. It is fragile and bears on its inferior face a short process, perhaps the stylohyal. The pterygoid process of the sphenoid originates opposite the anterior border of the posterior alisphenoid foramen. The latter is large. Its superior border is continued as a ridge backwards and a little outwards, and over- hangs the foramen ovale. This foramen is smaller than the alisphenoid, and is a narrow oval, looking outwards and forwards. It is situated .015 M. external to the anterior apex of the foramen lacerum anterius, and a short distance within the small internal glenoid tuberosity above mentioned. The condyloid foramen is round and large, and is situated near the anterior border of the basioccipital, where the posterior border of the foramen lacerum posterius is excavated for the jugular vein. There is a small and thin- walled otic bulla. There are no postglenoid nor supraglenoid foramina. DINOCEEATA. 593 The posterior molar has a wide floor extending from the posterior or straight transverse crest, to the cingulum This crest is low, and has a low tubercle near its apex behind The other molars have strong fore and aft cingula, but none at the ends. The worn surfaces are first V-shaped, later arrow-shaped. The first premolar has a curved outer crest and an inner conic tubercle. Measurements. ii. Diameter of occipital foramen and condyles 092 From exterior end condyle to external border of mastoid 058 From exterior end condyle to post-glenoid process 053 Width of skull at glenoid surface between post-alisphenoid foramina 29'2 Width of skull at glenoid surfaces between post-alisphenoid foramina 040 Width of basioccijntal anteriorly 015 Trans viTse diameter of last npper molar 045 Transverse diameter of third premolar 029 Length of molar series 163 Found by the writer in the Bridger formation of South Bitter Creek, Wyoming, in the Mammoth Buttes of the Washakie Basin. ? UlNTATHEEIUM sp. Uintafheriuvi sp., Cope, Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 582. Plates xxxiv, xxxv. A part of a large skeleton of a species of the Dmocerata was found by myself lying on a plateau of the Mammoth Buttes, Wyoming. In the absence of any part of the cranium, I have been unable to indentify it either as to genus or species. A cervical vertebra preserved, is so much more robust than that of Eobasileus pressicornis, that I originally referred the species to Uintatherium, in accordance with the descriptions of the coi-re- sponding vertebrae of the genus given by Marsh. It is the belief of Messrs. Scott, Spier, and Osborne that the cervical vertebrae oi Loxolophodon are not as much abbreviated as in Eohasileus, so it becomes possible that the present animal is a species of the former genus. As the Princeton paleon- tologists have, however, described some species of suj^posed Uintatherium from the same neighborhood, ( f/! leidianum and U. princeps), the present specimen may belong to one of these. The description and figures are given to elucidate the characters of the suborder. The species is one of medium size in the order, but was absolutely larger than the Indian rhinoceros. 38 0 594 THE BEIDGEE EPOCH. The bones consist of several vertebrae, some carpal bones, and the entire hind limb of the left side except the toes and the cuneiform and navicular bones. The odontoid process is very stout, with a descending trihedral apex Length M. .078; diameter at base, .048. A dorsal vertebra, with a single (anterior) capitular articular face, is quite concave in front M. Diameter anteroposteriorly 057 Diameter vertically 094 A cervical vertebra has the proportions of the dox'sal as to its centrum, thus differing materially from species previously described. The articular surfaces are slightly concave. M. Length (anteroposteriorly) 065 Diameter, vertical 087 Diameter, transverse 100 The femur resembles that of the other species already described, but is remarkable for the relatively small size of the head. While the lengths of the bone are not very diflPerent, and the expanse of the great trochanter about the same, the head of L. cornutus is large, the present one is very much smaller, and that of E. pressicornis intermediate There is a rudi- mental third trochanter, and the condyles are as large as, and similar to, those of E. pressicortiis. The external marginal condylar ridge is quite short. The shaft is broken and some small pieces lost; it is now 26 inches long, but was no doubt longer when complete. Measurements of femur. II. Exjianse of great trochanter 230 Diameter of head 109 Diameter of shaft at middle 093 Diameter above condyles 15-2 Diameter at extremity of condyles 139 Diameter (vertical) of inner condyle 125 The tibia is perfectly preserved. It is short and stout, and with mass- ive extremities. The outer basal part of the spine remains, and is promi- nent. The cotyli are not oblique; the inner is sub-round, the outer trans- verse, widening outwardly; their long axes are at right angles to each other. The spine is a low ridge of contact of the cotyli. The superior DIXOCERATA. 595 fibular face is a transverse oval; the inferior much smaller than in E. ^nes- sicornis. This shaft is contracted, and flattened behind and on the inner side. The distal extremity is transverse, less truncated for the fibula than in E. pressicornis, less convex behind, and with a less prominent external malleolus. The point dividing- the astragalus behind is more prominent. Measurements of tibia. M. Total length 398 Diameter of head, longitudinal 080 Diameter of head, transverse 138 Diameter of shaft, transverse 063 Diameter of shaft, anteroposterior 060 Diameter of distal articulation, anteroposterior 077 Diameter of distal articulation, transverse 113 Diameter of distal extremity, fore and aft 093 Diameter of distal extremity, transverse 185 These measurements show that this bone is considerably shorter than in E. pressicornis, though of equal distal diameter. In both species the measurements considerably exceed those given by Marsh for his Titano- iherium (?) anceps. The form of the articular extremities differs from both in being' more narrowed and transverse The fibula is larger proximally and smaller distally than in E. pressi- cornis. Diameter proximal articular face .0.^9; of the distal .045. The astragalus is similar in size and form to that of E. pressicornis, but differs in two jjoints. The posterior margin is deeply incised for the liga- mentous insertion, and the outer lobe is clearly cut to this fossa, on the inner side. There is a pit for a ligament on the convexity of the inner part of the middle of the tibial articular face. A third difference is seen on the inferior face The inner calcaneal facet is longer and narrower, and is margined on the inner side by a large fossa parallel to its axis, which is wanting in the other species. The calcaneum is short and wide; its only anterior articulation is with the cuboid, and is small. The heel is deeper than long, and is obliquely truncate downward and inward. Measurements of cahaneum. m. Length lOo Width 092 Depth in front . 056 Length of hoel 047 JDepth of heel 055 i.ength of cuboid facet . 038 596 THE BRIDGER EPOCH. The cuboid is a flat subtriangular bone with two unequal articular faces below. Length Olj"! Width ^"■0 Depth • ■■ -0^1 Length of cuneiform (anteroposterior) 040- Depth of cuneiform 01^ The humerus of a third specimen may or may not belong to this species. It was found in another locality. Its condyles are much less oblique than in tliat one described under E. pressicornis, and the olecranar fossa is shallower. It belongs to a larger animal ; see Measurements of humerus. M. Transverse diameter distally (7.75 inches) 19* Transverse diameter, inner condyle 125 Remarks. — The remains were discovered by the writer in the Bridger Bad Lands, on South Fork of Bitter Creek, Wyoming. BATHY0PSIS Cope. Amer. Naturalist, 1881, p. 75. Bull. U. S. Geol. Surv. Terrs., 1881, p. 194. The characters of this genus can only be given as seen in the mandi- ble, the only part of the skeleton in my possession Dentition : I. H ; C. 1 ; Pm. 4 ; M. 3. Incisors, canine, and first premolar forming an uninter- rupted series, which is separated by a diastema from the molar series. The molar and premolar teeth are constructed on an identical pattern, present- ing slight modifications from front to rear. This consists of an anterior elevated transverse crest, and a posterior heel, with raised posterior border; between these is situated on the external side an elevated cusp, which sends, a low ridffe inward and forward. The inner extremity of the anterior crest is cusp-like, and is accompanied by a second internal anterior cusp imme- diately posterior to it. The mandibular ramus has great vertical depth, its- inferior border being convex downward thi-oughout its entire length. Sym- physis coossified. The above characters indicate a new genus of considerable interest. Its form differs from that of the two genera where it is known, viz, Uinta- therium and Loxolojihodoii, in the much greater development of the inferior expansion. In Loxolophodon it has been shown by Messrs. Speir and DINOCEEATA. 597 Osborne to be represented by a mere convexity. In Uintatherium, Marsh has discovered it to be confined to the anterior part of the jaw, as in the saber-tooth cats. In Bathyopsis it extends to the entire length of the ramus, giving an outline in profile much like that of 3Ie(/atherium. The anterior extremity of the symphysis projects beyond the line of the anterior border of the inferior expansionr The characters of the inferior molars in this and other genera of Dino- cerata are very peculiai-. In Bathi/opsis they are constructed on the plan of those of insectivorous marsupial and placental mammals, so as to lead to the suspicion that its food consisted of Crustacea,, or insects of large size, or possibly of thin-shelled moUusca. Bathyopsis pissidens Cope. Loci supra cilali. Plate XXIX b, figs. 1-3. The lower jaw is not much larger than that of the Malayan tapir, but as this part of the skull is disproportionately small in this order, it is prob- able that this species is of considerably larger size than the one mentioned. The symphysis mandibuli is quite narrow, and its superior excavation is deep. It extends as far posteriorly as the middle of the diastema. It has considerable vertical thickness. The anterior edges of the lateral expan- sions are truncate, and present an obtuse angle outward, which forms the anterior boundaries of the slight concavity of the lateral face. The middle of the expansion below the first premolar tooth is slightly convex. This wall incloses a large internal expansion of the dental canal, which issues in a large mental foramen. This foramen is situated near the middle of the vertical diameter of the expansion, and below the anterior part of the diastema. It looks downward and forward. The external face of the posterior part of the ramus is nearly plane The inner face is vertical to a line which corresponds with the inferior border in Coryphodon^ and then slopes obliquely outward to the inferior margin. The base of the coronoid process rises vertically from the line of the alveolar border, and its external edare forms an anterior border for the masseteric fossa. The inferior border a of the fossa is not defined. The inferior border of the ramus is decurved posteriorly, and projects inward considerably beyond the plane of the jaw. 598 THE BRIDGEE EPOCH. The pi'emolars differ from the molars in having all their diameters, excepting the vertical, reduced. The fourth premolar only differs from the first true molar in the less elevation of the posterior border of the heel, and in a little smaller transverse diameter. The external part of the heel of the last molar rises into an obtuse cusp ; the remainder of the border is tuber- cular The heels of the other true molars end in simple recurved trans- verse edges. On the premolars their posterior extremities are not recurved. The anterior face of the anterior cross-crest of all the molars is concave, and on the second premolar it looks obliquely inward. The posterior or second anterior inner cusp- is obsolete on the second premolar. The enamel on all of these teeth is, excepting where worn, rather finely wrinkled. The first premolar is not preserved, but its alveolus indicates that it is one-rooted and rather robust. The sizes of the alveoli of the other anterior teeth are arranged in the following order, commencing with the largest : C ; I. 2 ; I. 3. The alveolus of the. canine is compi-essed, and has more than twice the anteroposterior diameter of the largest incisor. The alveoli of the first and third are subround ; that of the second is somewhat compressed. Measurements. m. Length from the middle of the second incisive alveolus to the extremity of the last molar 1950 Length of the series of consecutive molars 1 170 Length of diastema 0240 Diameter of alveolus of Pm. I OO'.tO Diameter of alveolus of canine 0250 Length of premolars 0460 ■ vertical 0130 Diameters of Pm. II < anteroposterior 0130 ( transverse 0090 ! vertical . .0120 Diameters of Pm. IV < anteroposterior 0105 ' transverse 0120 I vertical 0100 Diameters of M. I.. . < anteroposterior 01.55 ' transverse 0110 I vertical 0176 Diameters of M. III< anteroposterior 0260 ( transverse 0180 The appeai-ance of the ridges of the anterior part of the jaw of the Batliyopsis fissidens, together with the remarkably large dental canal and mental foramen, strongly suggest that the animal possessed a large and perhaps prehensile lower lip. From the Wind River, Wyoming. J. L. Wortman. DINOCERATA. 599 Fig. 26. Fig. 27. Fig. 29. Fig. 30. Figures co-nicii from Osborne's Memoir on Lnxnlophodon and rinlatherium Firrs. 26 .ind 28, one-eislith natural size ; figs. 27, 2«, anil 30,'one IVmrth natural size. F g 20, rinlafhrriiim Icidiainun. Fig. 27, superior nioUir teeth of do, from below. Fig. 2S, Loxolophodonspierianum. Fig. 29. mandible of supjK'sed Loiolophodon from above; a, iuferior molars, external side. Fig. 30, inferior incisors of supposed Loxolophodun, external and superior views. 600 THE PUEECO FATJfTA. A considerable part of the dentition of the mandible of this species was found in the Big-Horn bad lands. This includes an incisor tooth, which is quite characteristic, and renders it probable that the anterior parts of the jaws differ considerably from those of other Uinatheriidce. The root is sub- round. The crown resembles a good deal that of the species of Corypho- dontidce. It is higher than wide and has a subacute apex. One edge of the crown is convex, and the other concave. The external face is concave in both directions, and has no ridges nor cingulum. The inner face is con- cave longitudinally and convex transversely. The convexity is median and has a longitudinal concavity on each side of it. No internal cingulum except a trace at the base of the concave edge. The edges are obtuse even when unworn, and the enamel is obsoletely rugulose. Measurements of yiicisor. I auteroposteiior 012 Diameters of crown < transverse 020 ( vertical 020 Diameters of root ^'^°*<'™P°^*''"°'" *^,J'^ < transverse 014 This incisor (see Plate LVIII a. Fig. 7) is very different from the kind seen in Loxolopliodon. Messrs. Scott, Spier, and Osborne have shown that genus to have these teeth with compressed two-lobed crowns, a type un- known elsewhere among Mammalia. TALIGRADA. Since the preceding pages defining the suborders of the Amblypoda were printed, I have learned and described the characters of the genus JPantolamhda^. These indicate the existence of a third suborder of the Amblypoda, which I have called the Taligrada. In the first place, the phalanges (including ungual) show that the genus is ungulate. Secondl}', the astragalus has a large distal facet for the cuboid bone. This proves that the genus cannot be referred to the Taxeo- pod order. The question as to whether it belongs to the Amblypoda or the Diplarthra would be decided by the carpus, but that part is unfortunately not preserved, and I have to rely on empirical indications for a provisional 'American Naturalist, 1883, April, p. 406 (March 151. TALIGEADA. 601 determination. Apai't from the astragalus, the characters are those of the CondijlartJira rather than of the Perissodactyla, and it is therefore to be sup- posed that the carpus has also the characters of that order. This would place the genus in the Pantodonta, which has the carpus nearly that of the Taxeopoda, and the tarsus of the Biplartlira. The points of resemblance to the Condylarthra are the following: The ilium is narrow. The humerus has an epitrochlear canal. The superior molar teeth have but one internal lobe. The resemblances to the Pantodonta are these: The cervical verte- brae are plane and short. The femur has a third trochanter. The premax- illary bone is dentigerous. The astragalar trochlea is as in the Periptychidce, and the Prohoscidia ; that is, without groove, and slightly convex antero- posteriorly, thus differing from that of the Pantodonta. The dentition is especially like that of the Amhlypoda in general, and that of the superior sei'ies is unlike anything known in the Diplartlira. I propose to place this genus in the AmUypoda for the present, next to the Pantodonta, but it cannot enter that sub-order on account of the form of its astragalus. These sub-orders of AmUypoda will be compared as follows: Astragalus with a head distinct from trochlea, with distal articular facets . . Taligrada. Astragalus without head ; distal facets subiuferior Pantodonta. In the sub-order Taligrada, the single family Pantolamhdida: presents the followino: characters: Superior and inferior molars with the cusps developed into Vs. Post- glenoid process present; postympanic and paroccipital not distinct All the vertebras with plain articulations. Humeral condyles without inter- trochlear ridge. Femur with third trochanter. Digits of posterior foot probably five. Metapodial keels small and posterior. PANTOLAMBDA Cope. American Naturalist, 1882, p. 41f-. Proceedings American Philosophical Society, 1883, p. 553. A considerable part of the skeleton of a species of this genus ha\ing been sent me by Mr. D. Baldwin, I am able to throw much light on the affinities of this curious genus. Canine teeth distinct; dental series continuous. Superior molars all triangular; that is, with a single internal cusp. External cusps of premolars (302 THE PUERCO FAUXA. unknown; of molars two. Internal cusp V-shaped, sending its horns ex- ternally as cingula to the anterior and posterior bases of the external side of the crown, without intermediate tubercles. Inferior true molars with a crown of two Vs, the anterior the more elevated. Premolars consisting of one open V, with a short crest on a short heel, as in Coryplwdon. Dental formula : I ^- ; C. ; P-m. ' - ; M. - ; the last inferior with 6 1 ? 4 3 a heel. A strong sagittal crest. Auricular meatus Avidely open below. Large postparietal, postsquamosal and mastoid foramina. Cervical vertebrae rather short; other vertebras moderate, the lumbars not elongate. A large tail. Humerus with a large internal epicondyle. Femur with all the trochanters large. Ilium with the anterior inferior spine well developed. Metacarpals short, plantigrade. Phalanges of second series flat, and of subquadrate outline. The astragalus has a wide head, but no neck, as it is not separated from the trochlear portion by a constriction. It is as wide as the trochlear portion, but about one-third of its length extends within the line of the malleolar face of the trochlear portion. The navicular face is flat, that of the cuboid bone is convex vertically, and one half as long horizontally as the navicular, and only half as deep. These two facets are continuous with the sustentacular below. Interior to all of these, on the internal tuberosity of the head, is a sub-round facet looking inwards, like that characteristic of the genus Bathmodon, but relatively. larger. A con- tinuous facet is seen on the adjacent edge of the navicular. The use of these facets is unknown. The brain case indicates small and nearly smooth hemispheres, extend- ing with little contraction into a rather large cerebellum. The olfactory lobes are produced anteriorly at the extremity of a rather long isthmus If we consider the dentition alone, Pantolamhda is the ancestor of the Coryphodontidce. The history of the feet requires further elucidation. In describing this genus and species, I remarked, loc. cit, that they were "founded on a mandibular ramus, which supports the first true molar, and the last two premolars. The characters of these teeth remarkably resemble those of Coryphodo7i. * * * * it will be for additional / TALIGRADA. 603 material to deinonstrate whether this genus belongs to the Amhlypoda or Perissodactyla.'''' From what has preceded it is quite evident that the ensemble of characters is predominantly that of the former order. It is now apparent that the type of superior molar tooth which pre- dominated during the Puerco epoch was triangular; that is, with two ex- ternal and one internal tubercles. Thus of forty-one species of Mammalia of which the superior molars are known, all but four have three tubercles of the crown, and in this thirty-eight triangular ones we may include those of three species of Periptychus, which have a small supplementary lobe on each side of the median principal inner tubercle. This fact is important as indicating the mode of development of tlie various types of superior molar teeth, on which we have not heretofore had clear light. In the first place, this type of molar exists to-day only in the insectivorous and carnivorous Marsupialia; in the Insectivora, and the tubercular molars of such Carnivora as possess them (excepting the planti- grades). In the Ungulates the principal traces of it are to be found in the molars of the Coryphodontidce of the Wasatch, and Dinocerafa of the Bridger Eocenes. In later epochs it is chiefly seen only in the last superior molar. It is also evident that the quadritubercular molar is derived from the tritubercular by the addition of a lobe of the inner part of a cingulum of the posterior base of the crown. Transitional states are seen in some of the Periptychidce (Anisonchus) and in the sectorials of the Procyonidce. Pantolambda bathmodon Cope. American Naturalist, 18b2, p. 418. Plate XXIX d. The bases of the inferior Pni. iii and iv are subquadrate, the inner side rounded, that of the iv relatively the wider. On the iii the median keel constitutes the heel ; on the iv, the keel is in the center of a wide heel. No cingula. The first true molar has an anterior cingulum, but no external one. The enamel is wrinkled where not worn. Diameters of Pm. iii, an- teroposterior, .009 ; transverse, .007 ; of Pm. iv, anteroposterior, .009; trans- 604 THE PUEECO FAUNA. verse, .0085. Width of first true molar in front, .0083. Apparently abo'it the size of a sheejD. The second and more perfect specimen of this species includes a con- siderable part of the skull, with maxillary bone and teeth, the latter bone not continuous with the others. There are thirteen vertebrae from all parts of the column; more or less of two humeri, neither with the head, both ilia; the proximal part of the femur; the astragalus, navicular, and several metatarsals and phalanges. The posterior part of the skull is very opossum-like. It is long and narrow, and the sagittal and lateral occipital crests are much produced. Above the foramen magnum the occipital bone is deeply concave. The lateral occipital crest divides at its inferior portion into two ridges, which run nearly parallel and inclose between them a shallow lenticular fossa. The posterior ridge terminates in a short oval tuberosity, the paramastoid jDrocess, which bounds the auricular meatus posteriorly. The anterior terminates higher up, at the superior anterior angle of the tuberosity, with- out expansion, on a level with the superior edge of the meatus, thus not producing a post-tympanic process. The internal extremity of the post- glenoid process is produced into a narrow ridge which extends inwards and then forwards, bounding an oval fossa arranged anteroposteriorly. Its internal border is indicated by a narrow tuberosity, between which and the ridge before mentioned is a longitudinal groove. The anterior temporal ridge is an obtuse angle continuing the half of the sagittal crest to the postorbital angle. The muzzle is naiTowed upwards, and the nasal bones, though not narrowed, are together, obtusely roof-shaped. The facial por- tion of the premaxillary bone is remarkably wide anteroposteriorly, the width nearly equaling the depth in front of the canine tooth. The malar bone is very prominent, extending laterally much beyond the maxillary above the molar teeth. It presents no postorbital angle, but has on its ex- ternal face a wide groove. This is overhung by a strong ridge anteriorly, which descends anteriorly and ceases above the anterior part of the second true molar. The groove runs out below, and becomes distally two planes, a lateral and an inferior separated by a prominent angle. The zygomatic fossa terminates anteriorly in a sinus which is opposite to the anterior edge TALIGEADA. 605 of the third premolar. The posterior border of the palate is a little concave near the internal extremity of the last molar, and then curves posteriorly. The median portion is lost. The mandibular rami are partly preserved, together with the part of the symphysis between the canine teeth. The symphysis is coossified, has a nearlv vertical direction, and is flat transversely in front. The rami are compressed, and somewhat thickened below. The inferior outline is con- cave below the coronoid process (which is lost), and the angle is very prominent. It is broadly rounded in profile, and extends a considerable distance posterior to the base of the condylar process. Its external border is somewhat revolute; the infei'ior border is very slightly incurved. The masseteric fossa has an anterior border, and is marked off from the angle posteriorly, Init it fades out below. The parieto-squamosal suture is rather elevated in position above the base of the zygoma, but descends posteriorly to reach the occipital below the mastoid foramen. The nasal bones encroach considerably on the frontals posteriorly, reaching to opposite the postorbital angle. In this this animal resembles some of the species of Phenacodus. The nasal, naso- maxillary, and maxillo-premaxillary sutures are distinct and even. There are two post-squamosal foramina, and five postparietal, with two or three on the squamoso-parietal suture. The condylar foramen is distinct from the foramen lacerum posterius. It is probable that there is a postgle- noid foramen. The relations of tlie foramen ovale are not certain. There are several small foramina in the front of the symphysis. The superior true molars only ai'e preserved with parts of the alveoli for the fourth premolar. The first and second molars are similar, but the second external V of the third is much reduced, owing to the oblique tiimcation of the postero-external side of the crown. It is broken off" in the specimen. The external Vs of the first and second molars are much flat- tened inwards, and have slightly concave external faces. There is no ridge or tubercle, but a weak angle only, to distinguish their external planes. The anterior is a little lai-ger than the posterior, on account of the exten- sion of the anterior external angle. The latter has a slight anterior hook or recurvature. The internal V is rather acute, and is a little anterior to a 606 THE PUEECO FAUNA. transverse-liue dividing the crown, eqaially. There are anterior aud poste- rior basal cingula which do not meet at the internal extremity of the crown (this portion is damaged on the second molar), and which disappear at the line of the apices of the external Vs. There is a weak cingulum at the external base of the external Vs. The enamel is delicately wrinkled, or smooth where subject to attrition. The alveoli of the cai)ine and third supe- rior incisor show that they are large teeth. Of inferior teeth only parts of the crowns of the M. i and M. iii are preserved. The limbs of the anterior Vs ai'e elevated and sharp-edged, and the posterior terminates in something like a cusp internally. The third true molar has a well-developed median angle on its external side. The heel is long. The inferior canine alveoli indicate flattened roots and a crown directed upwards. The incisive alveoli form with the canines a con- tinuous series, and the median is a little larger than the first and third. Crowns lost. Measurements of skull. M. Leugtb from supraoccipital crest to posterior end of nasal bones 0. 1035 Length of sagittal crest 08T W'idth between superior edges of squamosals 025 Anteroposterior extent of glenoid surface 017 Anteroposterior extent of meatus auditorius 010 Length of cavity containing cerebrum and cerebellum 050 Long diameter of occipital condyle 018 "Width of both nasal bones at middle 0185 Length of facial process of premaxillary anteroposteriorly 01.') Llevatiou of orbit above molar teeth 019 Production of angle of mandible beyond posterior base of condyle 014 Depth of jiroduced portion of angle 027 Length from angle to anterior border of masseteric fossa 050 Depth of ramus at posterior edge of last molar 0285 Depth at lirst true molar 0275 Thickness of ramus below first molar 0115 "Width of symphysis above between the canines 018 Length of superior true molars 0285 Diameters M.i^''°**''<'P°^t''"°'^ *^11 ( transverse 017 Diameters M. n ^ anteroposterior Oil ( transverse 017 Tr.-knsverse diameter of M. iii 0165 Length of inferior true molars on base 032 Diameters M.i^^°*''''''P°«*^'''°'' "l^S ( transverse 008 D.ameter8o/5a«eofM. iii^'*°*^^''Po«*«^"°^ ^^* ( transverse 007 Anteroposterior diameter of superior canine alveolus, not less than 013 TALIGRADA. 607 The vertebrce \ireserved include two cervicals, six dorsals, two lumbars, and two caudals. The centra increase regularly in size to the lumbars. Their articular faces are distinctly biconcave, except those of a median distal caudal, where their convexity exceeds the median concavity. The cervicals are rather short, having proportions like those of Cory- phodon and various carnivorous animals. The centra are wider than deep, and the posterior concavity is greater posteriorly than anteriorly, and is surrounded by the thickened edge of the centrum. Below the parapophysis the inferior face is concave, and each fossa diverges outwards, leaving the median plane wider beliind than before. In the vertebrje preserved there is no liypapophysial keel. In a sixth or seventh cervical tliere is no ver- tebraterial canal, unless it perforate the "transverse process" at a distance from the centrum. A stronof groove from the neural canal excavates the superior side of the parapophysis and turns anteriorly to where it is broken ■off. A capitular rib-fossa is not distinct, hence I am not sure that this cen- trum is the seventli. In the first three dorsals preserved, which represent the more important part of the thoracic region, the posterior articular face is more concave than the anterior. In the posterior of these, the anterior costal facet is larger and more distinct than the posterior. In the two others the posterior is large, and the anterior is not to be seen, and is probably wanting, although the centra are somewhat injured at that point. These three dorsals are of different dimensions, showing a rapid increase posteriorly. None of them have inferior keels or fossae, but the first has a median angle. In the third the breadth is greater in relation to the length than in the first ; and the second is intermediate. In the remaining three dorsals the increased width is re- tained, and the length increases. The centra become more depressed, and more excavated below the diapophyses The middle line becomes more prominent in the fifth and sixth. The bases of the diapophyses are narrow and depressed. The costal facets are anterior, and present laterally. The best preserved lumbar is elongate and depressed, and the anterior face is quite concave. It is not keeled below, and there is a considerable nutritive foramen on each side of the middle line, which is connected with the inferior base of the diapophysis by a shallow vertical wide groove. An G08 THE PUERCO FAUNA. anterior dorsal with robust and flattened diapophysis is longer than wide, and equally moderately concave at both extremities, which are subround. The neural spine and z3'g-apophyses are well developed. There are con- siderable sjDaces for the attachment of a chevron bone, which are continu- ous with the rim of the articular face of the centrum. The inferior surface is concave on each side of a medium median surface, wliich is concave ant'eroposteriorly. A more elongate caudal has two diapophyses on each side separated liy a sinus, tlie anterior the smaller. The middle line both above and below is angulate medially and flattened at the extremities. Anteriorly above there is a small tuberosity directed upwards and forwards on each side, the remains of the neurapophyses. Measurements of vertebrw. M. ( auterposterior 014 Diameters of C. v or vi-? transverse in front 017 ( vertical iu front Oil i auteropostirior 012(> Diameters C. vi or vii< vertical in front 0113 ( transverse in front 017 ( anteroposterior ,017 Diameters of an anterior dorsal/ vertical in front 013 ' transverse in front 0155 I anteroposterior 019 Diameters of a posterior dorsals vertical iu front 0l5iS ( transverse in front 0175 / anteroposterior 02'2 Diameters of a more posterior dorsal-? vertical in front 014 ( transverse in fnmt 022.5 ( anteroposterior 026 Diameters of a lnml)ar< vertical iu front 01'25 ( transverse in front 022 I autero])osterior 0225 Diameters of an anterior caudal < vertical in front 0147 ( transverse in front 017 anteroposterior 024 Diameters of distal caudal^ vertical iu front 013 transverse iu front 0125 Zygapophj'ses of four vertebrae are preserved. They are flat except in one case they are a little and in another more convex. They are not subcylindric as in Mioclcenus, Mesonyx, &c. A supposed inanuhriwn sterni is represented by the anterior T-shaped portion. It is broadly truncate in front, and the superior straight trans- verse edge is I'ecurved. The body of the bone which extends posteriorly TALIGEADA. 609 las a vertical oval section, the inferior angle narrowed and subacute. It is broken off. The superior point of the truncate anterior face looks as though divided between two flat articular faces, perhaps for clavicles. Im- mediately behind the lateral superior angles of the front are two small deep fosssp, each perhaps for a first hsemapophysis. The position of the bone is, however, uncertain. Measurements. M. -r.. , .. /. 4. ( vertical 016 Dw-mietera ol front ; ( transverse above Oaa T, , e , .., • (transverse 0110 Diameters crown ot Pm. iv^ i anteroposterior 0090 Diameters M.ii^=^"*^'"°I"'^»«"*'^ ^^^l i transverse Ol.iO 622 THE EOCENE FAUNA. M. Length of inferior dental series from I. i to M. iii, inclusive 0920 Length of inferior molar series 0780 T-,- i v • r • • (anteroposterior 0075 Diameters base inferior canine < '^ „„^. C transverse OUoO Length last three premolars 0265 Length base Pm. ii 0090 Length base Pm. iii .0087 Length inferior true molar series 0320 ^. , ,, ..(anteroposterior 0106 Diameters M. ii .' ' „„_„ ( transverse 0U7b T^. . ,, ...(anteroposterior 0153 Diameters M. 111.? ' j(ai < tr transverse 0076 Length of symphysis (olilique) 0360 Depth of ramus at diastema .0200 Depth of ramus at Pm. iii 0230 Depth of ramus at M. ii 0280 Vertical diameter of orbit (?distorted) .. 0285 Jaws and teeth of more than twenty inciividuals of this species were brought from the Wa.satch beds of the Big Horn River by Mr. J. L. Wort- man. They vary somewhat in size, some being a Httle smaller than the individual above described. The latter was as large as a fully grown sheep. Systemodon semihians Cope. Paljeontological Bulletin No. 34, p. 184, Feb. 20, 1882. Plate LVI; figs. 3-4. This species was also abundant in the Big-Horn region, jaws and teeth of sixteen individuals having been obtained. Its dimensions are a little smaller than those of the S. tapirinus, especially as to the premolar teeth. There is also a short postcanine diastema, which is not seen in the S. ta- pirinus. The proportions of the maxillary series are represented by a left max- illaiy and premaxillary bone, with all the teeth in place, but the crowns lost from the first premolar anteriorly. The crowns of the true molars are somewhat worn, so I confine the description of these to the premolars. The third and fourth have considerable transverse extent, the latter being wider than long. The second has scarcely any internal tubercle, but only a low postero-internal heel. The internal tubercle of this tooth is large in S. tapirinus. The crown has two cusps, the posterior lower. The last two premolars have two external cusps close together. The}' have also an ante- rior external cingular lobe, as in the true molars. There is a posterior LOPHIODOXTID^. 623 external basal lobe in the third premolar, but none or a rudiment on the fourth. No internal cingulum on the premolars. The superior true molars, although worn, show a prominent anterior external basal lobe, and no com- plete internal cingulum. The base of the crown of the first premolar is naiTOW anteroposteriorly, and it has two roots as in S. tapirinus. It is in close contact with the second premolar, and is separated from the base of the canine by a space a little less than its own anteroposterior diameter, and less than the diameter of the canine. The base of the crown of the latter shows that it is not a large tooth, and has a wide lenticular section. The base of the external incisor is rather large, and is compressed. Meastirements of superior teeth. M. Total leugtli of superior series 0720 Tot.'il length of molar .series 0310 Total length of premolar series 0250 Diameters base of canine ^''°t«''"P°^'''''i°"^ ^"^^ ( transverse 0040 Length of base of Pm. i 0040 Diameters Pm. iii 5 •''°'«^°P''«*«""^ 0"'0 ( transverse 0078 Diameters Pm.iv^'^"»"»P°«t,*irior 0070 < transverse 0U90 Diameters M.,ii^'^"**™I"'^'''"°^ 0100 < transverse 0125 Some superior molars in better condition than those last described exhibit the following characters: The intermediate tubercles are fused with the internal, forming a continuous cross crest, but their apices are dis- tinguishable. The external cusps are subconical and are well separated. The anterior and posterior cingula are strong, the external is weaker, and it is wanting from the posterior part of the internal base of the crown. A portion of a mandibular ramus, supporting six molars, presents the following characters: The teeth are a little smaller than those of 8. tapirinus, the reduction being especially visible in the premolars. The cones of the crowns are more distinctly separated by notches than in that species, and are quite distinctly conic. The anterior ledge of the true molars is distinct, and there is a median posterior tubercle of the first two, which is repre- sented by the wide crenate-edged heel of the third true molar. The ante- rior-internal cusps of the last two molars are double or bilobed ; that of the first is last. The anterior cones of the fourth premolar are subequal, and 624 THE EOCENE FAUNA. the posterior external cone is elevated. There is a trace of the posterior internal. There is also an anterior ledge. The heel of the third premolar rises to a median blade and posterior cusp. The anterior cusp is elevated and compressed, and supports a small internal lateral cusp. The base of the crown of the third premolar is elongate. All the teeth are rather com- pressed, and there is only a trace of an external cingulum. The ramus is compressed and moderately deep. The dental foramen is large, and its superior border is on a level with the posterior base of the crown of the third true molar. Its inferior base is in line with the base of the crown of the second true molar. Measurements of mandible, M. Length of last s-x molars 0o30 Length of true molars 0310 ( anteroposterior 0065 Diameters third premolars transverse 0040 (vertical 0052 t anteroposterior 009J Diameters second true molar < transverse 0000 ( vertical 0062 T^- _ i 4.1 ■ 1 t 1 S anteroposterior 0120 Diameters third true luolars ' '■ (. transverse OOfaO Depth of ramus at Pm. iii 0170 Depth of ramus at front of M. iii 0220 The nearest ally of this species outside of the genus Systemodon is probably the Hyracotherium craspedotmn Cope. This species was brought from the Wind River bad lands, and does not occur in the Big-Horn col- lection. It is about the size of the -S'. semihians, but is a true Hyracotherium, with a diastema behind the fii'st premolar. The strong cingulum which characterizes it is not found in the 8. semihians, and the inferior molars are wider and more robust. HYRACOTHERIUM Owen. Transactions of the Geological Society of London, 1841, pp. 203-208. British Fossil Mammals, pp. 419- 423. Gervais Paleontologie Fraufaise, p. — . Cope, Report U. S. Geol. and Geog. Expl. Surv. W. of 100th Mer. Capt. G. M. Wheeler, 1877, iv, pt. ii, p. 2ri8. Dental formula, I. -; C. -; Pm. ^; M. 1 Three diastemata in the O 1 4: O upper jaw, i. e., behind the third incisor, the canine, and the first premolar, respectively; two in the lower jaw, behind the canine and first premolar, LOPHIODONTlDiE. 625 respectively. Superior incisors with flat, transverse crowns. Superior first premolar without inner lobe. All the other molars with two external tubercles in the form of compressed cones. The true molars and last pre- molar have an additional external tubercle in front of the anterior cone, which is an elevation of the basal cingulum. It is variously developed on the second and third premolars. Second premolar with the inner lobe like a wide cingulum ; the third and fourth premolars have one internal tubercle, and one or two smaller ones between it and the external tubercles, the anterior of which forms, on wearing, with the inner tubercle, a single trans- verse band of dentine. True superior molars with two internal and two intermediate tubercles, which form on wearing, oblique transverse bands. The anterior one of these passes anteriorly to the base of the anterior external cusp. The first and second inferior pi-emolars have no internal tubercles. The third and fourth have them on the anterior pai-t of the crown, but not on the posterior. The true molars have two pairs of opposite tubercles, the third and last adding a posterior fifth lobe or heel. The internal tubercles of the true molars have a circular section ; the external ones are V-shaped in section. The posterior limb of the V is directed toward the internal posterior tubercle; the anterior limb extends diagonally toward the other internal tubercle. The limbs of the anterior V have correspond- ing directions, the anterior terminating at the anterior border of the crown of the tooth. The species of Hyracotherium difi"er in the relative developments of the intermediate tubercles of the superior molars, of the distinctness of the tubercles of the inferior molars, of the lengths of the diastemata, and of the development of the cingula. In this genus the nasal bones are well developed, and join the pre- maxillaries to form the boundaries of the external nares. There is a strong postorbital process of the os-frontis, which does not inclose the orbit jjoste- riorly by reaching the zygomatic arch. The latter jjresents no postorbital process upward. The postglenoid process is rather short and obtuse. The meatus auditorius externus has no osseous floor external to the petrous ■chamber. The paroccipital process is well developed, and is distinct from 40 c 626 THE EOCENE FAUNA. the smaller posttympanic. There is a sagittal crest. The hamular pro- cesses are well developed. The infraorbital foramen is of medium size The incisive foramina are large. There is an alisphenoid canal. The foramen anterior to its anterior opening I take to be the rotiindum, and in front of the latter is a larger foramen, probably the / orhitosphenoidale, but as I cannot find the optic foramen anterior to it, it ma}' include the latter also. It is very probable that the foramen ovale is not distinguished from the / lacerum anterius. The / postglenokleum is distinct, grooving the posterior base of the postglenoid process. There is no supraglenoid foramen, but there are two or three postsquamosals. The / condyloideiim is quite distinct from the / lacerum posteriiis. I cannot be sure that there is a postparietal foramen; two near the proper location in H, ventkolmn appearing to be in the squamosal bone. The mastoid, if present, is not enlarged into a fissure, as in various recent genera. The symphysis of the mandible is coossified at maturity. The con- dyle is well elevated and the coronoid process is produced. The cranial characters above enumerated are derived from skulls of H. ventkolmn and H. craspedotum. The details are generally much like those of Anchitherium (anceps), omitting of course the generic and family characters, seen in the double-crested premolars in continuous series In the absence of the supraglenoid foramen we see an approximation to types of Perissodactyles other than those of the equine line. The following generic characters in the skeleton are derived from the H. venticolum. Twenty vertebrae of one individual of H. venticolum are preserved ; of these, three are cervicals, twelve are dorsals, and six are lumbars. The axis has the cylindric odontoid of other primitive types, and the atlantal facets are well separated There are no transverse or vertical foramina, but the vertebrarterial canal is present. The paradiapophysis is acumi- nate, and is directed backward. The spine is elevated, and is extended both anteriorly and posteriorly. The third or fourth cervical is rather elongate, and has the vertebrarterial canal. The transverse process is extended both forward and backward, and each extremity is acuminate. The articular faces of the centrum are weakly opisthoccelous, and are very LOPHIODONTID^. 627 oblique. Neural spinal low. The centra of the dorsals are weakly opis- thocoelous. On these vertebrae the interspinous foramina are never cut off from the interspinous intervals, as is the case in Tapirus. Except on the first two or three dorsals, the prezygapophyses are flat or convex surfaces directed downward and forward, and not recurved posteriorly or laterally, and separated on the median line by a notch. The neural spines are high, and the diapophyses are short. On the posterior dorsals anterior meta- pophyses are developed, and the tubercular facets are nearly sessile on their external sides. The metapophyses are separated by a groove from the prezygapophyses. The former send a ridge downward and backward on the last dorsals. On the lumbars the prezygapophyses embi-ace the post- zygapophyses laterally, but do not embrace them in the manner character- istic of the Ruminantia. A diapophysial i-idge appears and becomes promi- nent, its base extending the entire length of the centrum. The axis of this genus is that of a primitive ungulate of any type, and would even pass for that of a carnivore. The later cervicals are characteristically ungulate, but the further subdivision is not indicated. The remaining parts of the column show decided indications of equine i-ather than tapiroid affinity, in two points. These are : first, the absence of iso- lated interspinous foramina ; second, the narrow form and more revolute articular surfaces of the postzygapophyses. The scapula has a well-developed incurved coracoid process, resem- bling in this respect Corypliodon and Anchithermm, and difi"ering from recent Perissodadyla. Both tuberosities of the humerus are well developed, and inclose a simple bicipital groove, as in Tapirus and Anchitherium, having no trace of the additional groove seen in the later equine types. The condyles are characterized by the presence of a prominent intertrochlear crest, and by the fact that the condylar surface external to it, does not extend all the way on the posterior aspect. There are no epicondyles. The ulna and radius are distinct. The fomier is slender, most so distally ; the radius maintains its proportions throughout. Its head is a transverse oval, with- out interlocking angle below. The carpal svirface of the ulna is simple, that is, without dividing ridges. 628 THE EOCENE FAUNA. There are eight distinct carpal bones, those of the second series alter- nating with those of the first, and also with the metacarpals. The first bone of the second row, pi-obably the trapezium, was found displaced to a posi- tion behind the others. It carries no facet for a first metacarpal. There are four well-developed metacarpals, of which the V is shorter than the II. They carry the usual keel on the posterior distal face. The phalanges are rather short, and the unguis of digit III is w^ell expanded. The femur resembles in general the one figured by Owen as that of Pliolophus vuJpiceps* and that of P. vintamisf figured by myself The great trochanter projects far above the head, and there is ver}- little neck The fossa Ugamenti teris is large, as is the trochanteric fossa. The third trochanter is large, but less produced than in Tapirus and Equus. The rotular crests are about equally elevated, thus resembling Tapirus more than other recent Perissodactyla. The tibia is long and slender. It has a prominent crest, which is cut off" from the external border of the head by a deep notch. The crest is rather more prominent than in recent genera. There are both proximal and distal faces of attachment for the fibula, but I do not find the bone among those preserved. The inner malleolus is short, and its external face is obliquely beveled in front. It carries no facets, and is marked by a wade open vertical groove behind the middle. The trochlear gx'ooves are deep and quite oblique The patella is robust. The calcaneum is elongate and compressed. The astragalar trochlea is deeply grooved and has subvertical sides. The head is short but not sessile, and carries two distal facets. The external is quite narrow and fits the cuboid bone. The latter is longer than deep and deeper than wide. The peroneal hook is present. The navicular is relatively deeper than in the horse, and is closely united to the ecto- and mesocuneiform. The ento- cuneiform is a large flat and oval bone, on the posterior side of the tarsus. The mesocuneiform is the smallest. There are only thi-ee metatarsal bones, and no laidiment of a fourth. Each one is applied to the entire distal sur- face of its corresponding cuneifoi-m bone, without oblique articulation with an adjoining one. The distal articular surface of the median metatarsal has * Quarterly Jouin. Geol. Soc, London, xiv, p. 54. t Report U. S. Geol. Geog. Expl. Snrr. W. of 100th Mer., G. M. Wheeler, iv, pi. Ixv. LOPHIODOXTID.^. 629 the usual posterior keel. The corresponding extremities of the lateral metatarsals are unsymmetrical, the adjacent part of the condyle being more prominent, and the free portion shortened. In this respect they differ ma- terially from those of Hyrachyus, where the lateral metatarsals are nearly symmetrical, having the same character as the median one. The following comparisons maybe made between the limbs oiHyracothe- rium and other Perissodactyla. The coracoid process is larger than in either Triplopus or Hyrachyus. The proximal part of the humerus is a good deal like that of both those genera. In the distal extremity the external condyle is more prominent outwards than in either. The disproportion in diameters of the ulna and radius is greater than in Hyrachyus, but not so great as in Triplopus. In the carpus Hyracotherium is more like Hyrachyus than Tri- plopus, in the great inequality between the anterior faces of the trapezoides and magnum, from which it results that the metacarpus II has consider- able contact with the latter. In Trtplopus there is very little such contact, as the trapezoides presents as large an external face as the magnum. The unciform is also wider in the two genera with four metacarpals. There is considerable resemblance between the bones of the posterior limb of Hyra- cotherium and Hyrachyus, but the great trochanter of the femur is larger in the former. The proportions are more slender in the H. rentorum than in the Hyrachyus- ayrestis, but it cannot be assumed that such a character will distinguish all tlie species of both genera. Affinities. — Outside of the close relationships to other genera of Lophi- odonticlce, there are resemblances to the Anchitheriidce. The anterior cingular tubercle of the superior molar teeth of the family to which Hyracotherium is here refen-ed, is less developed in this genus than in most of the othei-s, while it is represented by a ledge in Anchiilierium. The humerus femur and tibia, are much alike in the two genera; so also is the zygapophysial articulation of the lumbar vertebrae. The elongate coracoid occurs in the Anchitherium hairdi. The differences in the feet, the forearm, and the axis are, however, great. The genus Triplopus presents an entirely intermediate condition of the fore leg and foot (hind leg unknown), but the crests of the molars are continuous and transverse, a structure which indicates for that genus a position in the line of Hyracodon or Rhinocerus, rather than Anchi- 630 THE EOCENE FAUNA. • fJierium. The ancestral relation of Hyracotherium to Anchitherium, which I have proposed,^ seems nevertheless very probable, but requires the intei'- vention of several intermediate forms. In the Lojihiodontidoe, one of these is Pliolophus (Orotherium Cope 1873). In the Chalicotheriidce through which the line probably passes, we have Lamhdotherium, and in the Palceotheriidce, Anchitherium. Species. — I am acquainted with six well-defined species of this genus from the Eocene formations of the United States, and there are probably several others. Two have been described from England. A third reputed species ( H. sideroliticum Pict. ) belongs to another genus, as observed by Kowalevsky, and, as I think likely, to the famil}^ Palceotheriidce. Many of the species oi Hyracotherium are represented. by numerous individuals; this is particularly true of the H. angustidens, one of the smallest of them. In giving a comparative table of characters of the species, it is necessary to confine it to the madibular rami and teeth, as it is the part most frequently found, and in some species the only part known. The characters thus ob- tained are as follows: Large; last molar, O^.O!! in lengtli; ramus, 0"'.018 in depth at last premolar; a strong external basal cingulum ; little anterior ledge ; anterior tubercles well separated. H. craspedotiim. Large; last molar, O^.OIS; ramus, 0'".020; anterior ledges not prominent; external ciugula H. vasacciense. Last molar, 0°.012 ; ramus, O^.OlGo ; second and third premolars, 0'".0135 ; external cingula JI. ventorum. Last molar, 0™.011 ; first molar, O^.OOST; ramus, 0"'.0]27; second and third premolars, O^.OISO H. osbornianum. First molar, 0"'.0065 ; ramus, O^.OISO ; second and third premolars, O^.OISS. H. angustidens. First molar, O^.OOSG ; ramus, O^.OllS; second and third premolars, O""r0OSO ..H. index. In the following table the characters of the superior molars are given so far as they can be ascertained. I have not seen them in H. oshorniannm. and index. a. External basal cingulum weak or wanting; internal strong. Diastema behind second premolar very short E. craspedotum. aa. Both internal aud external basal ciugula well developed. ' Proceed. Amer. Philo. Soc, May, 1873. "'Orohijfpus^' prociioninus Cope, Ann. Eeport U. S. Geol. Siirv. Terrs., Ib72 (1873), p. 647. LOPHIODOXTID^. 631 Diastema behind second premolar longer M. ventorum. Diastema ? size of H. ventorum H. rassaciense. aa. External ciugula strong; internal rudimental. Size less than R. rentonun R. angusticlens. Some names which I formerly associated with this genus are not in- cluded in the above list. Thus the Helotherium procyoninum must, I think, be referred to the genus Lambdotherium. I doubt the pertinence of the H. cuspklatum to this genus, though it is apparently a nearly allied form. The Lophiotherium sylvaticum Leidy, which I formerly placed here, is probably a Pliohphus, having the last inferior premolar like the first true molar. As this tooth is wanting from my specimens, I am not sure of the correctness of my fbrmer identification of it with this species, and so retain it in the above table, under the new name H. oshornianum. The species range in size from that of the kit fox (H. index) to that of the coyote {H. craspedotum). Their geographical and geological distribution is as follows : Wasatch. Wind Eiver. Bridger. R. vassacciense. R. craspedotum R. angustidens. R. ventorum. R. index. R. angustidens. R. oshornianum. Hyracotherium craspedotum Cope. Aajerican Naturalist, 1880, p. 747. Bulletin U. S. Geol. Survey Terrs., vi, 1881, p. 199. Plate LVIII ; figs. 1-2. This species is represented by a large part of both rami of the man- dible, and by a crushed skull, which contains the greater number of the molars of both sides. The upper surface of the "latter specimen is injured, and all anterior to the interorbital region is wanting. The H. craspedotum is of the size of the Systemodon tapirinum, but the tubercles of the inferior molars are not connected by cross-crests, and they all possess a strong external basal cingulum, which also extends round on the posterior base of the I and II true molars. Heel of fourth inferior premo- lar wide, with a diagonal ridge, two anterior cusps well separated, and no tubercle in front of them. Second premolar with narrow heel, which rises into an acute cusp on the middle of its posterior border. The anterior 632 THE EOCENE FAUNA. ledges of the true molars are rudimental. The heel of the last true molar is large and wide ; a median posterior tubercle represents it on the penulti- mate molar. The posterior part of the last molar rises with the base of the coronoid process. Enamel wrinkled. Measurements. M. Length of inferior molar series 05<; Length of true molars 03C Length of last molar 014 Length of Mrst true molar 009 Depth of ramus at last true molar 023 Length of diastema behind first premolar 003&- The superior surface of the skull of the second individual shows a low sagittal crest, formed by the convergence of two gradually approach- ing temporal ridges, which are continuous with the posterior border of the postorbital processes. The latter are rather long, and have a broadly rounded extremit}^, which is quite different from the acuminate form of those of the H. venticolum. A slight superior angle of the malar bone marks the poste- rior border of the orbit below. The lateral occipital and squamosal crests- are prominent, and send a branch downwards, forming the prominent edge of the posttympanic process, which is thus well distinguished from the surface of the paroccipital. The latter is the longer of the two, and is directed backwards, while the posttympanic points downwards and is sep- arated from the paroccipital to the base. There is no osseous floor to thfr neatus auditorius. The 05 petrosum is flat, and of a suboval outline. The postglenoid process is obtuse, and has a subtriangular section. The basi- occipital is posteriorly flat on each side, with a strong median keel ; ante- riorly the keel disappears, and the borders become more prominent. A short distance within the postglenoid process, the surface is roughened. Tlie infraorbital foramen opens above the anterior 2)art of the fourth premolar. A strong ridge from the pterygoid process passes upwards and backwards over the ahsphenoid canal. The foramina lacera anterius and posterius are rather large and are connected. The f. 1. posteriiis is con- tracted and terminates anterior to the / comhjloideum. The postglenoid foramen is large, and there is no supraglenoid. The diastema posterior to the first premolar is only as long as the dia- PERISSODACTYLA. 633 meter of one of the roots of that tooth, and much less than that anterior to it. The third and fourth premolars have the anterior external basal tubercle well developed, besides the two external cusps of the crown. The latter are subequally developed on the third premolar. The external faces of tlie molars have only the vertical ridge at the middle of each lobe, but on the true molars, while the anterior one retains its strength, it becomes obsolete on the second and third teeth. The result is that these cusps have, on wearing, a much more crescentic section than on species like H. venticoliim and R. angustidens, where the external convexity remains. There are the merest traces of external cingula on the molars to represent the strong ledges of the other species mentioned. On the other hand, the cingula of the inner bases of the crowns are strong, excepting opposite the posterior inner tuber- cle, where they are wanting. Anterior and posterior cingula pi-esent. Tha inner lobes of the crowns of the third and fourth premolars are rather wide anteroposteriorly, and the valley between the internal tubercle and the external wall is uninterrupted. It is bounded anteriorly by a ridge con- necting the points mentioned, which forms the anterior border of the crown, the anterior cingulum being absent or rudimental. There is a rudiment of the posterior median tubercle on the fourth premolar. Both intermediate tubei-cles are present on the true molars, the posterior forming a continuous^ ridge with the posterior inner tubercle, while the anterior is more distinct and is rather triangular in section. It sends a horn to the anterior angle of the anterior external cusp, which is quite distinct from the anterior basal cingulum and its cusp. The external face of the crown is wrinkled ; the internal is smooth. Measurements. M. Length of superior molar series 0565^ Length of superior premolars 0300 Length of base of first premolar 0066 Length of base of second premolar 0078 Width of base of second premolar 0050 Length of base of third premolar 0072 Width of base of third premolar 0080 Diameters base first true molar ^^°t*'^°P°«t^^"'^ ^ ""^^-^ ( transverse viw Diameters base third true molar 5 P ( transverse Olua Length from last molar to and including occipital condyle 0600 Width between inner borders of postglenoid processes 0:i60 Width of basioccipital bone opposite posttympanic processes 013(X 634 THE WASATCH FAUNA. A detailed comparison of this species with the H. ventorum^ shows, besides the superior size, the following characters: (1) The postgleuoid process is every way more robust, and is more obtuse. (2) The basioc- cipital bone is flatter, and the median keel does not reach the condyles as it does in H. ventonmi. (3) The paroccipital process is longer. (4) The postorbital process is rounded and not acute. The dentition of this species is in its dimensions and proportions inter- mediate between the two species of Systemodon. Its three premolars equal four of those of the S. semikians, while the molars of the two species are about equal. The two individuals of this species were found by Mr. Wortman, from the Bad Lands of the Wind River, Wyoming. A specimen having the ])roportiqns of the H. craspedotuni was found by Mr. Wortman on the Big Horn, but unfortunately it does not exhibit the characteristic cingula of the two dental series. The second superior pre- molar, like that of Systemodon semiJdans, has no internal tubercle. It is not certain whether there is any diastema posterior to the first superior pre- molar. I therefore cannot yet ascertain whether this specimen represents an undescribed species of Systemodon or Hyracotherium, or a strong variety of the H. craspedotum. The accompanying inferior true molars are inter- mediate in size between those of the latter species and the H. vasacciense. HyracothexIium vassacciense Cope. Expl. Surv. W. of 100th Meridian. G. M. Wlieeler, Vol. IV, Part II, p. 264. Plate LXVI, figs. T-11. Orohippus vasacciensis Cope, System. Cat. Vert. Eoceue New Mexico, U. S. Geog. Survs. W. of 100th M., 1875, p. 21. Lophiotherium vasacciense, Proo. Amer. Philos. Soc, 1872, p. 474. The locality from which the typical specimen of this species was pro- cured is near Evanston, Wyoming, in the beds of the Wasatch Epoch. They consist of two inferior molar teeth, one of which is attached to a part of the mandible. The latter tooth had suffered some erosion of one of its cusjjs, which led to the introduction of some abnormalities into the descrip- tion. Better specimens from New Mexico furnished the fuller descriptions and the figures given in the report of the Wheeler Survey above cited. As PEEISSODACTYLA. 635 no more perfect specimens having been received since that publication was issued, I do not repeat, but simply refer to it. A lower jaw from the Big-Horn Basin may belong to this species, or may possibly be a new sjDecies of PUolophus. The uncertainty is due to the fact that the crowns of only two molar teeth remain, one or both of which may be premolars. Supposing the anterior tooth to be the fourth premolar, it is shorter than the corresponding tooth in H. vasacciense. The bases of the second and third j^remolars are of about equal length, and each is considerabl}- shorter than that of the fourth premolai-. The crown of the third premolar is remarkable for the size of its internal tubercle, which is more robust at the apex than the external. Its position is very little posterior to the latter. It is unlike the latter in ha^ang no ridge de- scending to the anterior base. There is no distinct anterior basal tubercle. The tubercle of the heel is well developed, and sends a crest forward to the middle of joined anterior tubercles. On the internal side of the heel there is a rudimental internal tubercle. No external cingulum. The fourth premolar has a strong external and posterior cingulum, the latter culmina- ting in a median posterior tubercle. Measurements. m. Length of Pm. iii and iv Oil Length of M. i 007 Width of M. i posteriorly 0045 Depth of ramus at M. i 018 Besides the above a second specimen, a part of a lower jaw, was sent from the Big Horn Hyracotherium venticolum Cope. Bulletin U. S. Geological Survey Terrs., VI, 1881, p. 198. Hyracotherium vasacciense Cope. American Naturalist, 1880, p. 747; not of jirevious publications. Plates XLIXrt, XLIX 6, and XLIXc. Repi'esented by an entire skull, with many bones of the skeleton, of one individual, and the mandible of a second. In general, this species is to be distinguished from its near ally, the H. vasacciense, by the slender mandibular ramus. The depth of this bone is about equal to that found in the larger varieties of the H. angustidens, but the teeth are much larger, having the proportions of those of the H. vasac- ciense. This remark applies especially to the last inferior molar. 63 G THE WASATCH AND BETDGER FAUN^. The pieces which represent this species in my collection include the entire skeleton with the exception of the pelvis. They have been already mentioned in the course of the description of the genus. They are suffici- ently numerous to furnish a good basis for a complete restoration. The skull is somewhat distorted by pressure, and some of the long bones are more or less crashed. In general, the condition of the specimens is good. The form of the skull is not unlike that of a fox. It is elongate, with the orbit median in position, and the muzzle compressed. The profile is nearly horizontal from the end of the nasal bones to the summit of the occi- put, allowing a little convexity for the sagittal crest. The nasal bones pro- ject to a point exactly above the anterior border of the premaxillary bone, and the border of the nostril extends as far posteriorly as a point above the posterior border of the canine tooth. The orbit is of medium size, and its anterior border is above the middle of the first true molar. The slight angle of the inner superior border of the malar is a little behind a point above the posterior border of the last molar. The postorbital process is acuminate and quite elongate. Its posterior borders -pass into the anterior temporal ridges, and these soon unite to form a moderately elevated sa- gittal crest. The latter is quite prominent posteriorly owing to the decurva- ture of the brain-case. The lateral occipital crests ai'e prominent and con- vex, giving a cordate outline when viewed from above. They contract above the mastoid region, and continue to the extremity of the paroccipital process, and send a branch forwards to the squamosal process of the z3^goma, the latter ridge not being prominent. The occiput is concave on each side above each occipital condyle. The paroccipital process is narrow and fee- ble, and is separated from the posttympanic by a space as wide as the width of the meatus auditorius externus, which is considerably wider than the cor- responding space in H. craspeclotum. In that species, the two processes are in contact at the base. The postglenoid processes are short and pyramidal in form; less prominent than in H. craspeclotum. The glenoid facet is per- fectly flat, and has a longer diagonal-longitudinal than transverse diameter. The inner border is sharply defined from the surface which leads to the foramen lacerum anterius, but there is no rugose band at this point as in H. craspeclotum. The basioccipital and basisphenoid bones are strongly convex HYEACOTHEEIUM. 637 below, and the former is angiilate on the middle line for a short distance. The zygomatic arches are not expanded, and are much compressed, with flat external and internal faces. The ptyerygoid alae are deep, and support prominent acute hamular processes. Below these there is a longitudinal ridge on the external face, and still posterior is another external posterior ridge situated- near the alisphenoid bone, which sends a branch downward at nearly a right angle from its anterior extremity. The sphenoid descend- ing ala originates opposite the middle of the glenoid facet. The maxillary bone does not project much behind the last molar tooth. The palate is injured so that the depth of the notch cannot be ascertained. The side of the face in front of the orbit is injured on both sides. There is a lachrymal tuberosity on the anterior orbital border. The ascending branch of the premaxillary grows wider upward The borders of the nasal bones are decurved more and more, posteriorly from a flat apex. Viewed from above the apex is rounded, and the lateral outline gently convex. Their common median suture is distinct. The infraorbital foramen is above the anterior border of the fourth pre- molar. The other foramina have been generally described under the head of the genus. The condyloid foramen perforates a flat part of the basioc- cipital behind the foramen lacerum posterius, from which it is well separated. The superior border of the foramen magnum is notched. The elevated condyle, and full convex outline of the angle, are char- acteristic of the mandible of this as of other species of the genus. The coronoid process is elevated and has a convex anterior and concave poste- rior borders. There is no postcondylar tuberosity or crest, and the outline of the angle extends far behind the condyle. The mandibular ramus is compressed. The ascending ramus rises almost vertically a short distance posterior to the last molar. The sym- physis is narrow, and extends to below the middle of the first premolar. The inferior canines form part of an uninterrupted series with the incis- ors. The superior canine is separated from the superior incisors by a dias- tema. The first pi-emolar in both jaws is isolated. The second superior premolars have two cusps, and an internal ledge j^osteriorly. The third and fourth superior premolars are similar, the fourth displaying a little larger 638 THE WASATCH AND BEIDGER FAUNiE. transverse diameter. The true molars are of subequal dimensions. Their external cusps are subconic. All the superior molars except the first and second premolars are entirely surrounded by a basal cingulum, which rises into a low cusp at the anterior external angle of the crown. The third inferior premolar has its two median cusps well separated, and a wide poste- rior lieel. The heel of the last premolar is wider, but carries no internal cusp. The external cusps on all the teeth wear into well-defined Vs. Tlie posterior five inferior molai's have an external basal cingulum, but no other. Measurements of skull. u. Length of consecutive superior molars 0150 Length of diastema between Pm. i and ii 0035 Length of second premolar 0070 Width of second premolar posteriorly 0050 Diameters fourth premolar J ' ^ ' ( transverse 0090 y... , ,. , (anteroposterior '. 0085 Diameters second true molar •; ^ ( transverse 0112 Length of entire premolar series - 0580 Length of entire inferior true molar series 0'282 T^- . /. i .. 1 (anteroposterior 0080 Diameters nrst true molar < ' ( transverse 0060 Diameters last true molar ^^"^'^^P''**''"'"- ^12" ( transverse 0065 Depth of ramus at fourth premolar 0165 Depth of ramus at third true molar in front 0165 Twenty-two vertebrae are more or less perfectly preserved. Three are cervicals, twelve are dorsals, and six are lumbars. The yertebrarterial canal of the atlas issues at the middle of the lower side of the transverse process, in a longitudinal oval fossa. The inferior face between the trans- verse processes, is slightly concave on each side, and slightly convex in the middle. There is a slight atlantal process. The neural spine of the axis has an acute border, and is elevated behind, and extends forwards over the neural canal to above the middle of the odontoid process. The atlantal facets are subtriangular, and as high as wide. The anterior orifice of the vertebrarterial canal issues between two ridges, which extend from the upper and lower borders respectively of the atlantal facet to the transverse process. Below the inferior ridge the centrum is deeply concave to a high acute keel of the middle line. Between the atlantal facets this keel is ab- ruptly thickened, and it becomes a low obtuse hypapophysis below the HYKACOTHERIUM. 639 posterior articular face. The latter is subcordate, and as wide as deep. The centrum of the second or third cervical is deeply excavated below the trans- verse processes, leaving the middle line a prominent keel. This is not pro- duced into a hypapophysis of any prominence posteriorly. The transverse process is extended anteriorly to beyond the line of tlie articular surface. It has no transverse laminar expansion. The anterior face is very oblique, is moderately convex, and is deeper than wide. The neural canal is deeper than wide. " The neurapophy ses are concave on account of the prominence of an obtuse ridge which connects the zygapophyses. The neural spine is a keel. The articular faces of the first dorsal vertebra are not oblique, and are moderately opisthocoelous. The centrum has a median inferior angular line, on each side of which the surface is a little concave. The prezyga- pophyses are inclined at 45°, and the poslzygapophyses are horizontal. The tubercular facet is horizontal and projects about as far as the prezyga- pophysis which is directly above it. The capitular facets are large. The sides of the centra of the dorsal vertebrae which follow, are concave, and the middle line below is narrowed so as to be a ridge. The ridge becomes successively more obtuse posteriorly, becoming on the posterior dorsals an angle, which becomes quite obtuse on the lumbars. The neural canal grows smaller towards the posterior part of the column, its section being sub- round. On the posterior dorsals, the tubercular rib facet is near the ante- rior margin of the middle of the neural arch. A ridge passes from it to the posterior capitular facet. Behind the point of its disappearance this ridge continues to connect the two capitular facets. The neural spines of the dorsals are compressed, and present a simple edge posteriorly as well as anteriorl^^ On the posterior lumbars, the sides of the centrum below the base of the very wide diapophysis, become again concave. The articular faces of the lumbars are plane, and wider than deep. Measurements of vertebrw. ■' M. Leiieth of centmm of axis on inferior middle line \ I without odontoid 0-2o Length of base of nenral spine of axis 0'24 Elevation of neural spine posteriorly 016 Width of axis at atlantal facets 0200 €40 THE WASATCH ANB BEIDGEE FAUN^. M. Diameters of posterior articular face< .„^ t traus verse 0097 Diameters of neural canal anteriorly \ ' ,,noo < transverse .OOoa Expanse of postzygapophyses 0148 Length centrum of third or fourth cervical, on middle line below 0150 ... , ^ . *■ 1 f ^vertical 0090 Diameters of posterior articular face •; „^,. ( transverse 009o Diameters of neural canal behind ? ( transverse 0Uj2 AViuth, including transverse processes 0170 "Width at postzygapophyses 0190 f anteroposterior 0110 j vertical-posterior 0075 Diameters of first dorsal centrum <{ , posterior 0075 I transverse^ P^^.^^ ---•----■■■■■■■;;;;;;;;;;;;;;;;;;;;;;; ;^^3^ "Width of first dorsal with diapophysis 0:J60 C anteroposterior 0140 Diameters of Dorsal iv or v) ,|,)sterior^ vertical 0075 ( i transverse 0100 Expanse of prezygapophyses of D. iv or v 0090 ( anteroposterior 0130 Diameters of a posterior dorsal < „„„terior J ''""^•"'''^''l ^^''' ( < transverse 0100 Diameters of neural caual behiud \ nnan C transverse uuou / autoivposterior 0115 Diameters of a median luinbar< posteriori vertical 0085 ' (transverse 0120 Elevation of neural arch do 0050 "W^idth of postzygapophyses of do 0100 The glenoid cavity of the scapula is a wide oval, and, if completed next the coracoid, would be perfectly symmetrical. The posterior border of the lamina bends strongly backwards at a point below the middle of the length. The spine is nearest the posterior border up to this angle. Neither border of the lamina is thickened near the glenoid cavity, but the posterior becomes obsolete. Measurements of scapula. M. / transverse .' 0130 Diameters of glenoid extremity ) anteroposterior I '"^^^ coracoid 0200 ( ^ vrithout coracoid 0140 Anteroposterior width of neck 0140 The humerus is of moderate length, and the shaft is nearly straight. The head is well decurved posteriorly, where it is also narrowed. The external border of the greater tuberosity forms a curved crest of no great prominence, and the surface of muscular insertion of the same is not wider. HYRACOTHEEIUM. 641 though much longer, than that of the lesser tuberosity. The latter surface has a subround outline, and is quite smooth, although doubtless the surface of insertion of the subscapularis muscle. The facet for the teres minor is a subround concavity. The bicipital groove is short, owing to the early dis- continuance of its bounding ridges. Thus the deltoid crest is little promi- nent. At the distal part of the shaft the inner side is rather flat; the exter- nal has only an obtuse indication of the crest usual in many types, e. g., Hyracliyus agrestis. In this respect it resembles Triplopus cubitalis. There are no epicondyles. The principal or internal condyle is, as usual, a troch- lea with bounding ridges, of which the internal is an arc of wider diameter than the external, and is the more acute of the two. It is, however, not ex- panded as in many other mammals. The internal condyle has an articular surface which is flat transversely and is widest posteriorly. Its external border is obliquely directed inwards and forwards, but turns abruptly in- wards at the middle of the inferior or distal curve, thus discontinuing the condyle. Its place is then occupied by an oblique muscular insertion. This external condyle, which applies to an oblique process of the head of the radius, is much more prominent than in either Hyrachyus eximius or Triplopus cubitalis. Measurements of humerus. M. Length from edge of great tuberosity 096 Width of head with tnberosities (greatest) 022 Diaraetersof articular surface of head ^'^°*^^°P°^*''"°'" "1*^ ( transverse 018 Diameters of middle of shaft J •■^°t''™PO^*''r^°r 0095 I transverse 0100 anteropo8teriorJ°^^°°«'""'^g« 0120 c of outer ridge : 0125 transverse^ °^'°°«'''='"i''yl*^ 0090 ( of outer condyle 0060 Diameters of condvles < The radius is about as long as the humerus; it is thus longer than in Hyrachyus agrestis and not nearly so long as in TripJopus cubitalis. As it has no acute edges, its section is everywhere a transverse, flattened oval. The diameters of the shaft are subequal, increasing a little distally. The head is flattened below and above; and the internal and external borders are gently convex. The portion that applies to the external condyle is an aliform projection with an acute exteinal border. Its articular plane is 41 0 642 THE WASATCH AND REIDGER FAUX^. oblique to that of tlie rest of the head, extending upwards and forwards. The carpal articular face is three times as long as wide, and is rather con- tracted. The ulnar facet is rather large, and is sessile. The ulna is rather slender, becoming more so distal ly. Its section is triangular, interrupted on the middle of the shaft by an angular ridge, which extends from the superior to the inferior borders on the outer side. The olecranon is com- pressed, deep, and truncate. Its inferior border is a little thickened, and is continuous with the external surface. The inner side is marked by a rather elongate excavation, which fits the radius. The carpal facet is small and subsemicircular in form. Measurements of ulna and radius. M. Length of ulna - 0116 Length of olecranon 014 f at end of olecranon 012 1^ ii. j^ , I at head of radius 0085 Depth of ulua S ^ j j, <• , ^ nn<- at middle of shaft 006 I at carpal extremity 006 Length of radius 093 _. , /., J j7 J- < vertical . 0075 Diameter of head of radius < ( transverse 01.50 Diameters of radius at middle < ( trausverse 009 _, . . ^ -i • , 1 , i < vertical 0100 Diameters of distal enlargement I ( tr.ansverse 0145 Diameters of carpal surface J ^^'^ '"'' ( transverse 0110 Grooves for the extensor tendons are not seen on the superior side of the distal extremity of the radius. The scaphoid part of the carpal surfjice is very little recurved on the inferior face, and there is a mere trace of the fossa that bounds this recurved surface on the outer side or below the lunar facet in the higher Unffulata. In the carpus the scaphoid is the largest bone of tlie proximal row. Its radial facet has a greater anteroposterior than transverse diameter, and there is a short tuberosity behind it. Its trapezoid facet is a little larger than that joined by the magnum. The radial facet of the lunar is a good deal wider than deep. The posterior tuberosity is large and compressed, but does not project as far posteriorly as that of the cuneiform. Its ante- rior face is shorter than that of Triplojms cubitaUs, and has much the form of that of Hyrachyus agrestis. The cuneiform has an obliquely descending HTEACOTHEEIUM. 643 proximal articular face as in T. cuhitalis, not a concavely excavated one as in H. eximius. It differs from that of the former species in having the pisi- form facet largely facing posteriorly instead of proximally. The external face of the unciform is larger than that of the cuneiform, and nearly as large as that of the scaphoid, and is subquadrate in form. Its lunar facet is not large. The lunar and scaphoid facets of the magnum are subequal. It rises in a compressed arch posteriorly, and has the usual long decurved tuberosity posteriorly. The trapezoides has no posterior tuberosity, re- sembling in this respect the Hyrachyus eximius, and differing from the Trip- lopus cuhitalis, where it is present. The trapezium is a small bone represent- ing a liemisphere with one end cut off. It has about equal facets for the scaphoid and trapezoides. The pisiform is spoon-shaped with a stout neck, and the two proximal facets. It has a nuich thinner distal edge than either of the other species above mentioned, which is much more expanded than in the H. eximius. Measurements of carpus. Length of carpus ak lunar 0120 Width of carjnis at proximal row 0160 Diameters of scaphoid) f"^, .,.. { depth OIUU I length 0076 Diameters of lunar < median width 0055 ( depth (greatest) 0080 ^. ^ „ .„ (length 0068 Diameters of cuneiform < , " , . .. . < depth 0070 Length of pisiform 0100 Width of pisiform distally 0060 „. . ., < length 0040 Diameters of trapezium < , =>. „.^.. (depth 004o I length infiont 0iJ35 Diameters trapezoides< width in front 0035 ( depth 0060 f length in front *. 0050 „. ^ length at middle 0075 Diameters of magnum { .?., . e ^ nn-n " width in front 00.^0 l^ depth 0096 / length ■ 0070 Diameters of unciform .? width 0070 ( depth 0055 The femur is much like that of Pliolophus vulpiceps figured by Owen,^ and that of P. vintanus figured by myself^ The great trochanter is acumi- ' Quarterly Journ. Geolog. Soc, XIV, PI. IV. '' Report U. S. G. G. Surv. W. lOOtU Mer., IV, Pt. II, PI. XLV. 644 THE WASATCH FAUNA. nate with the apex slightly curved inwards. Its anterior and interior faces are abruptly contracted, the narrowing of the former commencing at a curved transverse ridge which is on a level with the head of the femur. The anterior convexity of the shaft commences at this transverse ridge. The third trochanter is rather prominent, and is recurved. The rotular groove is rather narrow and deep, and its smooth surface is continuous with that of the condyles. There is scarcely a trace of the fossa so marked on the inferior part of the posterior side of the shaft in Anchitheriiim. A part of the shaft above the third trochanter of this femur is lost, so that full meas- urements cannot be given. The tibia is rather slender. The internal femoral face is wider antero- posteriorly, and the external face is wider transversely. The former has a thin external edge ; the latter is separated from the fibular facet by a deep vertical border. I'he crest terminates below at the end of the proximal third of the bone. The shaft at its middle is flattened on the inner and posterior faces, and is rounded on the external side. A bourrelet surrounds the distal extremity just proximad to the astragalar articulation. It is in- terrupted on the inner side by the rather wide groove for the tibialis posti- cus tendon. The anterior and posterior angular extremities of the trochlear crest are of equal length with the internal malleolus. The following differences may be observed on comparing the bones of the leg above described with those of Hyrachyus eximius and Anchitheriiim anceps, which they considerably resemble. In the Hyrachyus the great trochanter is less acuminate, and the rotular crests and condyles present greater inequality between the sides. The crest of the tibia is divided in the Hyrachyus, entire in Hyracotherium venticolum. The internal malleolus is lessi produced in the former than in the latter. The resemblance between H. venticolum and the Anchitheriiim is greater. In the latter the principal difference in the femur is the greater anteroposterior extent of the great trochanter. In the tibia the principal difference is the excavation of the spine of the tibia at its summit, in which the Anchitherium resemblest he Hyrachyus rather than the Hyracotherium. HTEACOTHERIUM. 645 Measurements of posterior leg. Xength of femur below middle of third trochanter 088 Widthoffemnrat head 032 Anteroposterior diameter of head 009 Width of rotular groove at middle 009 Expanse of condyles 021 Length of patella 015 Width of patella Oil Thickness of patella 008 Length of tibia 1"22 Proximal diameter of tibial '*"t"°P°«*«"°^ ^"^ c transverse V'io _. . r \. C4. t. -jji < anteroposterior 009 Diameters of shaft at middle I ' ^„„ ( transverse UUa Diameters distal end of tibial '^"t'^^-'I^'^t'^"''' ^J^ ( transverse 016 The greater part of the posterior foot is preserved, the middles of the shafts of the metatarsals, and some of the phalanges being Avanting. The trochlea of the astragalus is narrower and less oblique than in Hyrachyus ■eximius. The ligamentous fossa of its external side is bounded by a vertical ridge in front ; the internal fossa is round, except where it runs downwards and forwards to the inferior side of the bone. The internal tuberosity of the head is insignificant. The calcaneum is not wide at the sustentaculum, and has no distal transverse processes. Its posterior distal extremity is sub- round. The calcaneum is a good deal like that of Hyrachyus eximius. The contact of the ectocuneiform and navicular is somewhat serrate, perhaps as the result of an injury. The proximal extremity of the navicular is mod- erately concave, and there is no tuberosity behind the astragalar facet. The latter has no marginal notch or fossa. As the mesocuneifomi is shorter than the ectocuneiform, the second metatarsal commences a little proximad to the others. Its shaft, as well as that of the fourth metatarsal, is absolutely lat- eral to the median one. The second is narrower than the fourth, but of the same depth. The section of the third is proximally a triangle with convex base and truncate apex. Distally th'^ section of the shaft is a flat trans- -verse oval. The transverse fossa proximad to the condyle is sharply defined at both proximal and distal borders. About half of the distal condyle of each lateral metatarsal is produced ; it is beveled so that its ectad edge is the more prominent, representing the keel of the median metatarsal. The ■contracted portion narrows forwards and holds a sesamoid bone. The prox- 646 THE WASATCH FAUNA. imal phalanges are not elongate. The distal legamentous fossae are perfectly defined. The lateral phalanges are but little shorter than the median, and were evidently used in progression. They are rather narrower and deeper than the median. Measurements of posterior foot. M. Length of calcaneiiru - 036 Deptli of free extremity (vertical) 009 Width at sustentaculum; 0125 Length of astragalus on inner side 017 / . , • (external 013 \ anteroposterior.; Diameters of trochlear < median 010 ' transverse 008 Transverse diameter of head 010 ) proximal < ' longitudinal 010 mteroposterior 009 ransverse 0073 ( longitudinal 005 Diameters of n.avicularj j,j.p^i„j,j] < anteroposterior 010 ^ i transverse 0065 Length of eetocnneiform 006 Width of ectocuneiform 008 Length of mesocuneiform 0040 Width of mesocuneiform 0055 Length of entocuneiform 0085 Width of entocuneiform 0070 terior 0090 -....„„...„ 0036 Diameters second metatarsal i , , . . ^mn anteroposterior UU7U V^ < transverse 0060 Diameters third metatarsal ■( f proximal ^'*"**''°P''***'™ I ( transverse . . . ] distal \ ■ I < J . ,< anteroposterior 0090 !P'^°^""'^^hransverse 0070 distal coudvle <, anteroposterior 00C5 L ■ (transverse UU7& C c anteroposterior 0075 I P''0^»°"^^ I transverse 0062 Diameters fourth metatarsal ^ , . * ■ _ nnrn 1 distal ""♦•'^"P^^tenor 00.0 ^ ( transverse UUoU r longitudinal OHO Diameters second proximal phalange < ^joximal^ vertical 066 ( < transverse 006 / longitudinal 012 Diameters third proximal phalanges^ proximal \ ^^'■''''^*1 ^""^ ( < transverse 00s Oenn'th ^^^ Diameters second median phalange ; " nnc /width 005 Oen"th 006 Diameters third median phalange t " , ,,,,j < width 008 The specimen above described is the most complete representative of the genus Hyracotherium that has ever been discovered. I owe it to my assistant, J. L. Wortman, who found it in the bad lands of the Wind River, HYEACOTHERIUM. 647 of Wyoming. A considerable jjart of the skeleton was extracted from the matrix by Mr. Wortman, and other parts were disengaged after their arrival in Philadelphia. The mandibular ramus of the second individual agrees in characters with those of the type specimen. Hykacotherium osbornianum Cope. Orotherimn sylvatieum Cope. Annual Report U. S. Geol. Survey Terrs., 1872 (1673), p. 607. Hyracotlus- riiim siihaticiim Cope. U. S. Expl. Surv. W. of 100th Meridian. G. M. Wheeler, IV, II, p. 262; not Lopiotherium sylratictim Leidy. Plate XXIV; fig. 23. This species is represented by a left mandibular ramus, which supports more or less of five molar teeth. The proportions of the jaw are about those of H. anyustidens, but are rather more slender than the smallest of that species that are known. On the other hand, the molar teeth are of larger size than in any of the varieties of that species. This combination of char- acters indicates a species distinct from the H. angustidens, a fact consistent with the diversity of the horizons in which the two species are found. The sides of the ramus are very flat, the outer side even a little con- cave along its middle, and neither side has any prominent convexity along the alveolar borders. The massetei'ic fossa is scarcely concave, and is only indicated by a little swelling of the external border of the ascending ramus. There is a mental foramen beneath the posterior root of the third premolar. The first true molar is the only one in which the grinding surface is well preserved. The external Vs are well defined, and their angles are directly opposite the internal cones. The latter are both simple, and have a round section. There is a strong anterior basal cingulum, which is joined at the middle by the anterior horn of the anterior V. There is an uninterrupted external basal cingulum, and also a posterior one which is joined by the posterior branch of the posterior V, close to the posterior inner cone. Enamel smooth. Measurements. M. Length of posterior four molars 034 Length of fourth premolar 007 Length of third true molar 010 Width of third true molar anteriorly 004 Depth of ramus at front of last true molar 014 648 THE WASATCH FAUNA, I formerly identified my specimen with the Pliolophus sylvaticus of Leidy, with which it nearly agrees in proportions. That species has a wide fourth premolar, while this has a narrow one, as in the species of Hyracotherium, although the crown is broken away so that I cannot see the structure of the crown. The crown of the first true molar is represented by Leidy as having an iutennediate tubercle, and a double anterior internal cusp. Neither of these characters is seen in H. osbornianum. This species is dedicated to Mr. Henry Osborne, of Princeton, New Jersey, one of the paleontologists of the College of New Jersey. The type specimen was found by myself on Black's Fork of Green River, Wyoming Territory. Hyracotueeium angustidens Cope. Orohippus angustidens Cope. System. Cat. Vert. Eocene New Mexico, U. S. Geog. Snrvs. W. of 100th Meridian, 1875, p. 22. Hyraeotherium angustidens Cope. Beport U. S. Ex. Snrv. W. of 100th Me- ridian, IV, Part II, p. 265. Plate XLIXo; fig. 16. This small species was originally found by myself in the Wasatch formation of New Mexico. I have not yet heard of its occurrence in the Bridger beds, but it is abundant in the Wind River bad lands, and still more so in those of the Big Horn, which are to be referred to the Wasatch epoch. The specimens obtained are, as usual, chiefly lower jaws, but a few maxillary bones and muzzles with teeth, were also found. While these agree in general with those from New Mexico, they present variations in proportions sufficient to require notice. In a specimen of variety C, below noted, the third and fourth pre- molars and the first true molar are preserved. The former have consider- able anteroposterior diameter, the third relatively the greatest. Its anterior intermediate tubercle thus almost takes the position of a second internal tubercle. There is a rudiment of a posterior intermediate tubercle on the fourth premolar. On both premolars the external cusps are distinct from each other. The anterior external cingular tubercle is well developed. In the ramus of another specimen of variety C, the anterior cusps of the fourth premolar are equal, and the angle of the outer descends to form HYRACOTHEEIUM. 649 an anterior basal cingulum. There is no trace of the inner posterior cusp which is seen in the genus Pliolophus. External cingulum scarcely a trace. Enamel nearly smooth. In the true molars the anterior ledge and posterior median tubercle are little developed; the oblique ridges are well developed, and the heel of the last molar elevated. The molars have a strong cingu- lum on the outer side, and the enamel is slightly rugose. The ramus is slender. Measurements of a New Mexican specimen. Length of the bases of three true molars 0.024 Length of the penultimate molar 0.007 Width of the same 0.005 Depth of the ramus at the last molar 0.0125 \ The variations from the above standard of measurement found in the Wind River specimens are as follows. There are three sizes which may represent different species, but this cannot be determined without better material : A. Depth of ramus at last premolar or first true molar, .0130; length of crown of first true molar, .0070; length of last true molar, .0100. Lower jaw of one specimen. B Depth of ramus, .0140; length of first true molar, .0065; of last molar, .0100. One lower jaw. C. Depth of ramus, .0155; length of first true molar, .0075; of last true molar, .0100. Two individuals. Portions of lower jaws of three other individuals in the Wind River collection are apparently referable to the H. angustidens. Variety A was obtained in the Big Horn basin north of the Wind River, by Mr. Wortman. The majority of the Big Horn specimens agree with the variety B, but two others occur, one a little smaller and the other a little larger than the aver- age. The former measures: length of last molar, .0090; of first molar, .0067; depth of ramus at M. i, .0120. The dimensions of the larger variety are: length of M. iii, .110; of M. i, .0067; depth of ramus, .0165. The New Mexican forms originally described exhibit combinations of several of these measurements. 650 THE WASATCH FAUNA. Hybacotherium index Cope. Report U. S. G. G. Expl. Surv. W. of 100th Mer., G. M. Wheeler, IV, Part II, p. 262. Orohippus index Cope. Systematic Catalogue Vertebrate Eocene New Mexico, 1875, p. 20. Orolherium index Cope. Paleontological Bulletin No. 17, p. 4, 1673. Represented by the mandibular ramus with many of the molars in good preservation. These number P. M. 3, M. 3. The last premolar is some- what like the first molar, but has but one posterior tubercle, and adds a cin- gular projection in front of the anterior pair. The first premolar has two roots; 'the second is compressed, and with a broad heel behind. In the molars the anterior tubercles are connected by a cross ridge; the posterior are a little more distinct from each other. The inner anterior tubercle is obtuse but not bifid, and its base is connected with the apex of the poste- rior outer by a diagonal ridge. There is a small median posterior tubercle on the No. 2, and a large heel on the last molar. It supports a conic tubercle, which is connected by sharp ridges with the tubercles preceding it. There is a cingulum on the outer face of the true molars, which does not extend on the base of the tubercle of the posterior pair. Measurements. M. Length of molar series 0.0350 Length of first premolar 0032 Length of third premolar 0055 Width of third premolar 0040 Length of second molar 0065 Width of second molar 0045 Length of last molar 0098 Depth of ramus at first premolar 0021 Depth of ramns at second molar 0023 I took this species from the bed on Bear River, Wyoming, from which were obtained the typical specimens of Bathmodon radiatis, Coryphodon latij)es, and Phenacodus primoevus. It is the typical locality of the Wasatch forma- tion of Hayden. The type specimen having been mislaid, is not now figured. PLIOLOPHUS Owen. Quarterly Journal of the Geol. Soc, XIV, 1857, p. 66. Orotherium "Marsh" Cope. Ann. Report U. S. Geol. Surv. Terrs., 1872 (73), p. 606. Report U. S. G. G. Expl. Surv. W. 100th Mer., IV, II, p. 258: numMarshii? This genus differs from Hyracothenum, so far as I am able to ascertain, in only one point. This is in the presence of two tubercles on the heel of PLiOLOPnus. 651 the fourth premolar tooth, instead of one. Most of the dentition and a good deal of the skeleton of the English P. vulpicejas have been described by Owen, and I have described nearly as much of the P. vintanus from New- Mexico. From these descriptions it is evident that the characters are in general those of Hi/racoiheriiim. Professor Ow^ens's diagnosis of Pliohphus does not specify the generic distinction above mentioned, for the reason that the mandibular dentition of Hijracotherium was unknown at the time he wrote. He did, however, give his reasons for distinguishing the genus from the latter, and on this account the generic name must be retained. I for- merly adopted for this genus a name introduced by Professor Marsh, but without certainty that he really had the present form in view in proposing it. Professor Marsh mentions the similarity between the fourth premolar and the first true molar. I regarded this statement as a definition of the genus, and therefore adopted it. An examination of the type specimen of Pliolophus vulpiceps in the British ^Vfuseum permitted me by Professor Owen, has satis- fied me that the American species I have called Oroilieriuni must be placed in the same genus. Species. — Besides the P. vidpiceps from the English Suessonian, four species have been described from North American formations, and a sixth is now added. Several of them are only known from mandibular rami, which are, in two of them, fragmentar}^. The Lophiotherium sylvaticum Leidy probably belongs to this genus, if not to the one to which Dr. Leidy referred it, a point which cannot be positively settled without a more com- plete specimen. I refer it to the immediate neighborhood of the P. cinctus as the most probably correct course. The species differ as follows: Internal tubercle of third interior premolar smaller than the external anterior, and posterior in position. /? Anterior inner tubercles of molars bifid. Dei>th of ramus at M ii, .017 P. vintanus. Pii Anterior inner tubercle simple. Depth of ramus at Pm. iv, .0155; length of Pm. ii, iii and iv, .018 P. cristonensis. Deptli of ramus at Pm. iv, .0135; length of Pm. ii, iii and iv, .0185 (Owen). P. vulpiceps. Depth of ramus at Pm. iv, .012; length of Pm. ii, iii and iv, .015 P. lavi. aa Internal tubercle of third inferior premolar as large as the external, and not much posterior to it. 652 THE WASATCH AND BEIDGEE FAUN^. Depth of ramus at Pm. iv, .011; length of Pm. iv, .0065; external Vs obtuse. P. sylvaticus. Depth of ramus at Pm. iv, .017; length of Pm. iv, .0065; external Vs acute angled. P. cinctus. P. sylvaticus and P. vulpiceps present an intermediate tubercle in the second inferior true molar, a character not present in P. vintamis and cristo- nensis. The peculiar appearances seen in Prof. Owens's figure of the last inferior molar of P. vulpiceps are due, according to its describer, to injuries produced in extracting it from the matrix. This genus occupies an intermediate position between Hyracotherium and Lophiotherium. Pliolophus cinctus Cope. Cligotomus cinctus Cope. Paleontological Bulletin No. 12., p. 2, March 8, 1873. Annual Report U. S. Geol. SuTV. Terrs., 1872 (1873), p. 607. Plate XXIV, fig. 26. The only indication of the former existence of this species which I pos- sess, is a mandibular ramus which supports the fourth premolar and the first true molar, and contains the alveoli of the other premolars, and the second true molars. There is a^ pretty long diastema behind the first premolar, and the second premolar was almost as large as the third. The fourth scarcely dif- fers in any respect from the first true molar, a circumstance which led me, when I first described the species, to regard it as a true molar. Both this tooth and the first true molar are characterized by the acuteness of the external cusps and the distinctness of the oblique ridges which extend in- wards from them, both anteriorly and posteriorly. The sections of these lobes form Vs, but they are distinct from the internal cusps, so that they are not identical with the molars of the species of the Chalicoiheriidoe. The anterior inner cusp is slightly bifid. The external base is surrounded by a distinct cingulum, which passes round behind the crown and supports a median tubercle. The ramus is rather shallow and has flat sides. The mental foramen is below the posterior limit of the diastema. HEPTODOK 653 Measurements. M. Length of molars from second to fifth, inclusive 026 Length of diastema 0037 Length of base of Pm. ii 005O Length of Pm. iv 0070 Width of Pm. iv 0050 Length of M. i 0070 Width of M. i 0050 Depth of ramus at Pm. ii 0126 Found on Cottonwood Creek, Wyoming. From the Bridger epoch. HEPTODON Cope. American Naturalist, 1882, p. 1029. Pachynolophus "Pom." Cope, Proceeds. Amer. Philos. See, 1881, p. 381, (not Pomel). ? 1 4 3 The dental formula is, I. -; C. - ; Pm. -; M. -. There is in both o 1 3 o jaws a considerable diastema between the canine and the anterior premolar, as well as one anterior to the canine. The inferior premolars diifer from the true molars, and the last of the latter has a fifth lobe or heel. This genus is in fact Lopliiodon with seven superior molars. The type of the genus is H. ventorum. It is only in this species that the maxillary dentition is known; I associate in the same genus two similar species known from the inferior dentition. I suspect that the Hyrachyus singularis Cope, from the Wasatch epoch of New Mexico, belongs to this genus. It is much smaller than the P. calciculus, which in turn is smaller than the P. ventorum. 1 originally employed Pomel's name PachynolojjJms for this geilus. Professor Kowalevsky's figures and descriptions^ show plainly that the genera are distinct, that genus being one of the Chalicotheriidce, and allied to Latnbdotherium. 'Monographic der Gutting Anthracotherium, Palaeontographica, XXII, p. 207, 1873. The ex- ternal lobes of the superior molars are suhequal and are separated by a vertical rib. The transverse crests are more or less complete. To this genns Professor Gaiidry (Enehainenients du Monde Animal), refers the Propalmotherium of Gervais, which was founded on Pachynolophus isaelaims, in 1849. Packy- nolophus bears date 1847. The European species are the following : I. Posterior cross crest of superior molars interrupted. P. duvali (type) ; P. eideroHHoua. II. Posterior cross crest ©f superior molars continuous. P. argenionicua ; P. iaaelanus. G54 THE WASATCH AND BRIDGER FAUN^. Heptodon posticl's Cope. Pachynolophua posticus Cope, Paleontological Bulletin, No. 34, i). 187, Dec, 1881 (published Feb. 20, 1882). Plate LVI; fig. 6. Both ranii of a mandible represent this large species. They are some- what injured, and the crowns of five of the molars only can be distinctly seen. The latter display the characters seen in the P. ventorum and other species of the genus. The transverse crests are well characterized, and the valleys between them uninterrupted. They are closed at the inner extremity by a low ridge nearly at right angles with the cross-crest posterior to them, as in the sjDecies of Bhiuocerus. The anterior of these bounds an anterior ledge, which is quite large on the last true molar. The latter has a rather narrow but prominent heel, which rises posteriorly. The fourth premolar has an anterior ledge, and wide heel with a diagonal crest which is median in front. The third premolar is similar, but smaller. The only cingulum is seen on the anterior part of the external side of all the true molars. Measurements, H. Length of crowns of posterior six molars 0700 Length of crowns of true molars 0440 ^ anteroposterior 0095 Diameters Pm. '^y \ ^^^^^^^^,^ 0070 Diameters M.ii^''"**^°P°^'«"''^ - '^^^'^ ( transverse 0095 Diameters M.iii 5 ''"^'"■•'P"^*''""'' "^l^" ( transverse anteriorly 0092 Depth of ramus at Pm. ii 0280 Depth of ramus at M. ii 0310 From the Big Horn basin and Wasatch epoch; J. L. Wortman. Heptodon ventorum Cope. Paehynolophus ventorum Cope, Bulletin U. S. Geol. Surv. Terrs., 1881, VI, p. 197. Lophiodon ventorum Cope, American Naturalist, 1880, p. 747. Plate XXIX a; figs. 4, 5. Portions of the crania of six individuals represent this species. These are mostl}- fragmentary mandibles and maxillary bones. The most charac- teristic specimen includes the left maxillary bone almost entire, a part of the right maxillary, and the posterior part of the left ramus of the mandi- ble, with the third true molar in place. HEPTODON. 655 This specimen demonstrates three prominent characters of the species: (1) There is no rib of the external wall of the superior molars dividing the areas that belong to the crescents respectively; (2) the transverse crests of the true molars are perfectlj^ continuous; (3) the first premolar is two-rooted (it is represented as two-rooted, by Pict^t, in the Pacliy)wIo2)hus duvali). The middle angle or summit of the anterior external crescent of the molars is a trihedral cusp, and it is well separated from the anterior cingular cusp. The transverse crests are curved obliquely backwards. On the premolars it is the posterior transverse crest that is wanting, and the width of the crown is maintained by a posterior basal cingulum not distinct in the true molars The premolars have less anteroposterior extent than the true molars, and they diminish in transverse extent anteriorly, so that the base of the crown of the first is anteroposteriorly wedge-shaped. The last three premolars have two external cusps joined together at the base, the posterior being rudimental on the second premolar. There is a considerable diastema between the canine alveolus and the first premolar. The transverse crests of the third inferior true molar are without inter- ruption, and the second sends a descending ridge forwards from each end. The heel is small, supporting a single cusp which rises from its posterior margin. It is larger than in the P. calciculus. Measurements. M. Length of maxillary bone from canine 074 Length of diastema OtC Length of four premolars on bases 027 Length of bases of three true molars 0320 Length of bases of first premolar 0076 _. ^ „ , , < transverse 0070 Diameters of second premolar { ,^„.,^ ( anteroposterior 00/0 _. , I. !• .-. 1 < transverse 0100 Diameters of fourth premolar i ( anteroposterior 0080 Diameters of second true molar J ■ ' ( transverse 0125 .^. , n ^, ■ , . , (anteroposterior 0114 Diameters of thud tnie molar.; '^ „,„^ ( transverse 0130 Length of heel of third inferior true molar 0032 Width of second crest of third inferior true molar 0074 Part of the left mandibular ramus, supporting five molar teeth, served as the first indication of this species. The last true molar is wanting. The second premolar has a short heel with a median cusp rising from its poste- 656 THE WASATCH AND BEIDGER FAUN^. rior border. The third premolar is injured. The fourth has a complete anterior transverse crest with a slightly concave edge. There is a strong anterior basal cingulum. The heel is wide and supports two cusps, a larger external one and a smaller internal one. The former is trihedral in section and is wrinkled on the inner face. In the other inferior molars the trans- verse crests have entire edges, and there is a narrow anterior basal cingu- lum, rather elevated in position. There is also a rudimental posterior one, but none on either internal or external side. Length of molar series, .064; of true molars, .040; of last true molar, .016; depth of ramus at second premolar, .020; at third true molar, .030. In a third specimen of lower jaw, both of the last molars are preserved. Their cross-crests are entire and with slightly concave edges. The heel is- well developed. The only cingulum is a weak one in front. Each extremity of the second cross-crest sends an angular ridge downwards and forwards. Length of last inferior molar, .0155; length of heel, .0040; width at anterior cross-crest, .0087. Heptodon calciculus Cope. Lophiodon calciculus Cope, Americam Naturalist, 18S0, p. T47. Pachynolophus calciculus Cope, Bulletin U. S. Geol. Snrv. Terrs., VI, 197, Feb. 26, 1881. Plate X:XIXo; fig. 6. The mandibular rami of two individuals of this species are in my col- lection. One of these contains all the molars except the first (second), with most of the diastema. As the maxillary teeth are unknown, it is not yet certain whether this species belongs to the genus to which I have referred it, or to Lophiodon. In one of the lower jaw^s there is a single-rooted first premolar on the side of the crest of the diastema. It is wanting in another, and is probably an inconstant character. This speciee differs from the P. ventorum in the possession of a single external posterior crest on the fourth premolar instead of two posterior tubercles. It is also considerably smaller, and the heel of the last inferior molar is smaller. The lateral ridges which descend anteriorly from each transverse crest are very little marked on the true molars, and there are no oblique ridges. There is a rudimental anterior basal cingulum, which is HYRACHYUS. 657 best developed on the last true molar. The heel of the latter is a low tubercle. The only lateral cingula are situated each at the base of the anterior lobe of the crown. In the third premolar the anterior cross-crest exists but is twisted backwards at the inner extremity. The heel is like that of the fourth premolar, and the anterior cingulum is better developed than in any other molar. The ramus is compressed and rather deep for the size of the molars. The anterior border of the masseteric fossa is not well defined. The symphysis is coossified and is contracted at the diastemata. The men- tal foramen is below the anterior root of the first (second) premolar. Measurements. M. Length of inferior moiar series 053 Length of true molar series 033 Length of last true molar 014 Width of last true molar anteriorly 008 Diameters of fourth premolar! ^"t^^oPo^t^""' 008 ( transverse 006 Depth of ramus at diastema 017 Depth of ramus at penultimate molar 025 Width of symphysis at diastema of No. 2 0115 The Wind River Eocene of Central Wyoming. J. L. Wortman. HYRACHYUS Leidy. Hayden's Beport, Geological Survey of Wyoming, 1871, 357. Proceed. Acad. Nat. Sci., Philada., 1871, p. 229. Cope, Proceed. Amer. Philos. Soc, 1873, p. 212. Annual Report U. S. Geol. Survey, 1872 (1873), p. 594. Leidy, Report U. S. Geol. Survey Terrs., I, 1873, p. 60. Scott, Spier, and Osborne, Pal. Report Princeton Scientific Expedn., 1878, p. 49. Dental formula: I. -; C. -; Pm. ^; M. -. Transverse crests of molars o 1 4 o and premolars continuous. Third and fourth j^remolars with two transverse crests; first and second with one or none. Inferior true molars with two subtransverse crests; premolars without cross-crests, excepting the fourth, which has one corresponding with the anterior crest of the true molars. Last true molar without heel. Inferior canines forming a continuous series with the incisors, but separated from the premolars by a diastema. Nasal bones produced posteriorly and anteriorly, contracting the anterior nares. Meatus auditorius externus not closed below. Posttympanic and paroccipital processes united for part of their length. Mandibular 42 O 658 THE BEIDGEE FAUNA. condyle pi'esenting superiorly; symphysis coossified. Postparietal and postsquamosal foramina present; mastoid small, if present; supraglenoid, none. Atlas with a vertebrai-terial canal perforating the base of the transverse process from behind, and issuing on the inferior surface. The vertebral artery then occupied a groove at the anterior base of the transverse process, and entered the neural canal by a large foramen well posterior to the occipital cotylus. Atlas and axis rather short; other cervicals more elon- gate. Odontoid process very robust, and a little flattened above. Atlantal facets well separated below. Other cervicals strongly opisthocoelons, and with transverse processes which are well extended anteriorly and posteriorly and but little transversely. The diapophysis and parapophysis are quite distinct in the sixth cervical; the former lateral and subcylindric, the latter flat and extended anteroposteriorly and directed downwards. The dorsal vertebrae have well-developed metapophyses. Anteriorly they rise above the diapophj^ses (tubercular articulations), and, as the latter diminish, stand above the prezygapophyses and increase in elevation. The prezygapo- physes of the lumbars embrace the postzygapophyses on the external side, as in the Equidce; more than in the Tapiridoe, and much more than Rhi- noceros. They resemble those of Hyracotlieriuin more than any of the types named. The neural spines are well develojied on all the dorsal and lumbar vertebrae. The interspinal foramina have no spinal foramina separate from them in the lumbar vertebrae. The sacrum is long and wedge-shaped, and consists of five vertebrae, all with well-developed neural spines. The ante- rior sacral is articulated to the diapophysis of the last lumbar as well as to the centrum, and the diapophysis of the last lumbar in like manner articu- lates with the diapophysis of the penultimate. The horse and rhinoceros display similar articulations. In the Tapirus terrestris the sacral articula- tion is less distinct, and that between the last two lumbars is wanting. The centra of the lumbars are plane in Hyrachyiis. The anterior ribs are, as usual, wider and flatter than the posterior, and articulate with the sternum, apparently without any intervening haema- pophyses. This is to be inferred from the facts that the ribs extend to the sternal segments and that no traces of haemopophyses are present. The HYEACHYUS. 659 latter may have, however, been very short and cartilaghious, and have been lost. There are more or less of five sternal segments preserved; they are all much compressed, the pra;sternum the most so; the prgesternum is twice as long as an}- of the mesosternal segments. In general, the sternum resembles that of the Bhinocerus much more than that of the horse. The scapula has a short but well defined coracoid process. The tuberosities of the humerus are well developed, and the greater is large and incurved. The bicipital groove is simple. Tlie condyles have an inter- trochlear ridge and a small external condyle. The ulna and radius are entirely distinct, and without proximal interlocking connection. The ulna is not ver}^ slender, and its carpal articulation is not so small as in Triplopus or Anchitherium. There are eight carpal bones. The pisiform is quite large ; the trapezium is small. The lunar articulates with both the mag- num and unciform. There are four digits in the manus, of which the second (first) articulates proximally witli the trapezoides and laterally with the magnum. The third (second) articulates proximally with the trapezoides and laterally with the unciform. The pelvis is rather elongate. The ilium has a contracted peduncle, and the crest is separated from the sacral plate by a long neck. The ischium is without sinuses posteriorly. The femur has the great trochanter produced proximad to the head, and separated from the general surface of the shaft by a basal angle. The third trochanter is well developed and the internal rotular crest is higher than the external. The tibia has a flattened and grooved crest, bounded by a notch on the external side of the head. The fibula is distinct at both extremities, and has a slender shaft. The calcaneiun is compressed and extends distally well beyond the astragalus, thus shortening the cuboid. The trochlear part of the astraga- lus is wider than in Hi/racotherium, and the head is shorter, thus resembling the tapiroid and rhinocerontic rather than the equine types. The cuboid facet is distinct. The mesocuneiform is a small bone, and the entocunei- form is large, flat, and i)osterior in position. Tliere are three posterior digits without rudiment of a fourth in the species studied, H. eximius. The second and third metatarsals articulate with one carpal bone only, while the 660 THE BRIDGER FAUNA. fourth articulates with the two inner cuneiforms, and has a small lateral con- tact with the ectocuneiform. The phalangeal articulations of the lateral metatarsals are but little unsymmetrical. The median ungual phalange is wide and flat, and has proximal lateral processes. The latter ungual pha- langes are unsymmetrical, and have but one, an external proximal process. The above general characters are derived from the study of one almost perfect skeleton of H. eximius. The aflinities they displa}^ are most rhinocerontic, then tapirine, and least equine, of the perissodactyle families. The unsymmetrical form of the external wall of the superior molars is represented among living types by the Bliynocerontidce only, while the transverse crests of the inferior mo- lars are shared by that family and the Tajnndce. The form of the sternum is rhinocerontic, while the first are much like thosfe of the tapirs. In the articulation of the lumbar vertebrae Hyrachyus is rather more equine. Species. — Eight species of this genus have been distinguished by Messrs. Scott, Spier, and Osborne,^ in a satisfactory way. I add another to the list, and copy their analytical table almost entire: I. A long diastema between lower canines and molars. aa Superior molars surrounded by a cingulum ; enamel wrinkled. Last molar with two external lobes in nearly the same transverse line. .H. intermedins. Last molar with two external lobes in nearly the same longitudinal line. .fl^. modestus. aa Superior molars with cingulum complete externally only. fi With anterior cingular cusp larger than anterior lobe. Ciugular cusp separate and no ridge from anterior lobe H. princeps. Cingular cusp nnited with anterior lobe by a crest H. imperiaUs. (i[i With anterior cingular cusp smaller than anterior lobe. Teeth and jaws larger -S. eximius. Teeth and jaws smaller , E. agrarius. II. Inferior diastema short. No cingula or additional lobes of superior molars; inferior molarr. with strong anterior cingulum S. impUcatus. II. Inferior diastema unknown. a No internal cingulum on superior molars ; the anterior crest with a distinct me- dian lobe. A strong internal projection of the external wall; enamel smooth; an internal ledge. T. amarorum. The Triplopus amarorum is mentioned here for comparison with the spe- cies of this genus. It resembles them in some portions of its skeleton. ' Paleontological Report of the Princeton Scientific Expedition of 1877-1878, p. 49. HYRACHYUS. 661 Six of the above species have come nnder my observation, together with two others of whose generic position I am not certain. One of these IS quite small and is probably the H. nanus of Leidy, which is said by Messrs. Scott, Spier, and Osborne to have only six inferior molars. My specimens are not sufficiently complete to indicate whether the species should be referred to Pachjnoloplms, which possesses that formula, or not. The second is intermediate in size between H. nanus and H. crassidens, and I have identified it with the Hyrachyus hoops of Marsh. Messrs. Scott, Spier, and Osborne state that that species has no diastema, and on this account they refer it to a distinct genus for which they employ the name Helaletes Marsh. My specimen does not enable me to verify these references. Hyrachyds princeps Marsh. American Journ. Sci. ami Arts, 1872, p. 125. Plate LII; fig. 4. This, the largest species of the genus, is represented in my collection "by the superior molar tooth of an adult specimen, Plate LII, fig. 4; and Ity a part of the mandibular ramus of another individual of immature age. Both the specimens were found by myself on South Bitter Creek, Wyo- ming, in beds of the Bridger epoch, of the Washakie basin. Hyrachyus sp. I Hyrachyus eximiua pt. Leidy Report U. S. Geol. Surv. Terrs. I Plate XXVI, figs. 9-10. Portions of mandibles of two individuals are too large to be referred to the H. eximius, and are considerably less in proportions of the teeth than those of H. princeps. They may belong to the H. imperialis of Scott, Spier, and Osborne, although the measurement of the second inferior molar, the only tooth of that series described by those authors, somewhat exceeds that of my specimens. I give these for comparison. Measurements. M. No. 1. No. 2. Length of three true inferior molars 060 .060 Length of second true molar 021 .022 Width of second true molar 015 .014 Depth of ramus at second true molar 045 ,03^ 662 THE BRIDGEE EPOCH. Specimen No. 2 is young, as the last molar is not protruded beyond the apices of the cross crests. Both specimens were found by myself in the Bridger basin on Cot- tonwood Creek, Southwest Wyoming. ITyrachyus EXiMius, Leidy. Hayden's Geo). Survey Montana, 1871, p. 361. Annual Report U. S. Geol. Survey Terrs., I, p. 6C, 1873; Plate IV, figs. 19-20. Cope, Proceeds. Amer. Philos. Soc, 1873, p. 213. Plates XXIIIa, fig. 1; LIII, fig. 3; LIV; LV; hVa; LVIIIa; figs. 5-6. This tapiroid left numerous remains in the sediments of the lakes of the Bridger epoch. I obtained parts of numerous individuals during my exploration in the Bridger basin during the summer of 1872, but did not obtain any fragments which I could refer to it, from the Washakie basin, whose deposits are supposed to be of the same age. The most character- istic specimens are: (1) An almost entire specimen, which lacks only the muzzle and skull anterior to the glenoid cavities, one fore-leg, and the caudal vertebrae; (2) Both mandibular rami with the atlas and axis; (3) The palatal part of a cranium with worn molar teeth; (4) A ramus man- dibuli with four posterior molars, all but the last in good preservation. The skeleton first enumerated is an unusually complete fossil, and has served as a basis of estimation of the generic characters of Hyracliyus. It was discovered by myself standing erect in the side of a blufi" at an angle in its escarpment. The entering face of the precipice cut off the nose of the specimen, which stood with regard to the topography like the winged bulls of the ruins of Nineveh. I occupied much time in removing it from its ancient position, and it is now mounted in a life-like attitude in my collection. Cranium. — In the specimen to be described, the anterior portion from the glenoid cavities is wanting. The sagittal crest is quite elevated, and the lateral occipital quite prominent, and continuous below with the superior margin of the squamosal portion of the zygoma. Four nutri- tions foramina pierce the parietal bone near its middle and above the paraoccipital process, and two enter the squamosal above the postglenoid process. The paroccipital process approaches near the occipital condyle HYRACHTTJS. 663 by its posterior border. I cannot discover the sutural boundaries of the mastoid bone, but that separating the paroccipital pi'ocess from the post- tympanic process in front of it is distinct. The condyle of the mandible is massive, and the posterior border of the latter extends backward with a slight obliquity. The foramen magnum has prominent supero-lateral mai'gins which are nearly straight, and unite at a right angle above. Measurements. M. Elevation of sagittal crest above foramen magnum 045 Width of bifurcation of crest bebind 033 Width of occiput behind meatus auditorius 070 Width between and inclusive of occipital condyles 046 Width temporal fossa at meatus 050 Width meatus auditorius 012 Width condyle of mandible 032 Depth of ramus behiud , 095 Vertebrce. — In this specimen the vertebrse anterior to the tail are fully preserved. There are seven cervicals, eighteen dorsals, seven lumbars, and five sacrals. As usual the seventh has no vertebrarterial canal. The atlas is deeply incised anteriorly above. It is rather short, and its traverse pro- cesses are flat, thin, about as long as broad, and with regular convex distal margin. The arterial foramen issues some distance above and within the notch which marks the anterior base of the transverse process. It enters at the notch at the posterior base. The neural arch is quite convex, and its anterior margin is obtusely rounded. The axis is near the same length, and bears a prominent and elongate laminate neural spine. Its diapara- pophysis is narrow and overlaps the parapophysis behind it three-quarters of an inch; it is pierced for the cervical artery. The centra of the third and fourth cervicals are about equal in length to that of the axis, but the remaining ones shorten successively to the seventh, which maintains a length somewhat greater than its width. The parapophyses of these, except the seventh, are flattened, and hav3 considerable anteroposterior extent, their extremities overlapping. A short and rather narrow and stout diapo- physis is present on the sixth cervical ; on the seventh it is larger, and espe- cially expanded anteroposteriorly at the base and truncate. There is no parapophysis. The fourth, fifth, sixth, and seventh have strongly opistho- coelous centra; that of the third is injured. 664 THE BEIDGEK EPOCH. Measurements. H. Length of the cervical series 175 Leugth of atlas between articular faces 046 Length of base of transverse process 035 Length of transverse process 020 Diameter neural canal in front 021 Diameter of anterior expanse 050 Diameter of total expanse 099 Length axis along basis neural arch 021 Elevation crest (rectangular) from posterior zygapophysis 036 Length parapophysis of fifth cervical on margin 051 Extent zygapophyses of fifth cervical on margin 048 Expanse zygapophyses of fifth cervical on margin behind 044 Elevation neural spine of C. vi. 056 Elevation neural spine of C. vii 075 Length centrum below ofC. Tii 028 Diameter of cup, about 032 The measurements indicate that the neural spines of the sixth and seventh are quite elevated, the latter neai-ly equal to that of the first dorsal The spines of the dorsal vertebrae are elevated in the front of the series, rising some distance above the scapulae. They shorten and widen rapidly from the middle of the series backward. The extremities of all from the scapula posteriorly are turned forward. The metapophyses are conspicu- ously elevated above the diapophysis on the eleventh dorsal, and on the eighteenth their elevation is about A that of the neural spine. The diapo- physis is extended beyond the tubercular articulation, on the eighteenth dorsal ; the extension and expansion increases rapidly on the lumbars. On the fourth they are as wide at the base as .6H the length of the centrum, and maintain their width, being directed anteriorly. On the sixth and seventh they are still wider and longer, and very thin. They present a projecting transverse surface backward one-fourth the length from the base for articulation Avith the seventh lumbar and first sacral respectively. The centra of the lumbars are depressed and slightly opisthocoelous, exce^it the last, which is flat. They are contracted and keeled below. The sacrum is long and narrow, and thoroughly coossified in the specimen. The diapophysis of the first and part of that of the second give attachment to the ilium. The intervertebral foramina are rather small. HTRAGHYUS. 665 Measurements. M. Length of dorsal vertebrje along middles of neural spines 0.420 Length of lumbars do 298 Length of sacrum along centra 170 Diameter centrum first dorsal (transverse) 019 Diameter centrum first dorsal (vertical) 019 Diameter centrum fifth lumbar (vertical) 020 Diameter centrum fifth lumbar (transverse) 0325 Length do 039 Length diapophysis sixtb do 065 Greatest transverse width of diapophysis sixth lumbar 030 Length centrum seventh lumbar 034 Transverse diameter centrum first sacral 036 Transverse expanse diapophyses do 086 Transverse diameter end of last sacral 020 Transverse diameter diapophysis do 043 Elevation neural spine second dorsal 095 Elevation neural spine seventh dorsal above scapula 035 Elevation neural spine eighteenth dorsal (from arch behind) 037 The ribs are long and slender, the first but little expanded distally and united with the prsesternum a little behind its middle. They number eighteen, but as the last is quite long, there may have been another pair of shorter ones not yet exposed in the matrix. Measurements. M. Length first 0.118 Width first, distally 018 Length eighteenth Uom tubercle \ '^0 Length sixteenth (end broken). ) < 223 There are four sternal segments preserved, with a fragment of another. They are distinct, and the first is the largest. It is a longitudinal plate, placed on edge, with the anterior border strongly excavated. The inferior margins of the succeeding segments are thickened, but the compressed form remains, the section being triangular. The scapula is large for the size of the animal. It has an approximately triangular form, the base being superior. The posterior angle is right, but the anterior regularly rounded. The apex supports the glenoid cavity on a neck which is contracted by a shallow excavation of the anterior margin. The latter is bounded next the glenoid cavity by the short obtuse coracoid, which stands a short distance above the articulation. The spine is long, rather elevated, with a regular convex border curved backward. It rises 666 THE BEIDGEE EPOCH. gradually from a low angular ridge of the middle of the external face of the neck. Measurements. ii. Length of three sternal segments 0. 147 Length of first sternal segments 084 Depth of first sternal segments iu front 044 Width of first sternal segments below 004 Width of third sternal segments 015 Length of scapula (median) 215 Width above (greatest) 130 Width of neck 036 With of glenoid cavity 035 Humerus.— The head is directed a little inside of directly backwards. The bicipital groove is very deep, and the inner tuberosity large and di- rected forwards. The external tuberosity is much larger, as usual in this group of ungulates, and rises in a hook-like apex above the level of the head. The external bicipital ridge is lateral, and not very prominent, extending on one-third the length of the shaft. The shaft is moderately compressed at the middle, but is transversely flattened below. It is nearly straight. The condyles are narrow, and the inner and outer tuberosities almost wanting; their position is marked by shallow concavities. The exter- nal continues in a lateral crest which turns into the shaft below the lower third. The inner condyle is both the widest and most prominent; the ex- ternal has its carina at its middle, and its external trochlear face oblique and narrow; narrowest behind. The olecranar and coronoid fossae are deep, and produce a small supra-condylar foramen. The ulna exhibits a large and obtuse olecranon, concave on the exter- nal face. Its glenoid cavity is narrowed and elevated behind; in front it widens, and there the ulna receives the transverse proximal end of the radius, which overhangs it on both sides, leaving the little elevations of the right and left coronoid processes about equal. The vertical diameters of the shaft of the ulna are about equal throughout. Its section is triangular, the base being next the radius for the proximal third. This is followed by an edge next the ulna, and the base of the section is on the outer inferior aspect, on account of the direction of an angle from a short distance beyond the outer coronoid process to the base of the ulnar epiphysis, where it dis- appears. Distally there are two other very obtuse ridges above this one. HYEACHYUS. 667 The extremity bears two facets, the larger for the cuneiform, the smaller for the pisiform bone. The radius is throughout its length a stouter bone than the ulna, and bears much the greater part of the carpal articulation, viz, with the scaph- oid, lunar, and part of the cuneiform bones. This articulation is transverse to that of the ulna, which is thus at one side of and behind it. The head is a transverse oval in section, the narrower end outward. The articular face consists of one and a half trochlese, the latter wider and internal. The shaft is a transverse oval in section, with an angular ridge along the middle externally, and the distal part proximally. A broad groove marks the upper face of the epiphysis, where the shaft has a vertical inner face. Measurements. M. Length humerus (axial) 0.270 Diameter head to bicipital groove •.... 037 Length along crest outer tuberosity (about) 052 Transverse diameter, distally O'*^ Anteroposterior diameter of inner condyle 042 Width olecrauar fossa 020 Length ulna '-^60 Depth olecranon distally 027 Depth at coronoid process "25 Depth of distal end 019 Depth at middle shaft 019 Length radius .- 200 Width of head 036 Depth of head 021 Width shaft at middle 021 Width near distal end (greatest) 037 Width distal articulation 030 The elements of the carpus are distinguished for length, and for reduc- tion of width. The anterior faces of all are considerably longer than broad, but the longest faces of the cuneiform, scaphoid, and trapezoides are antero- posterior. The facets are as usual in the carpus; scaphoid ^; lunar J; cuneiform |; trapezium \; trapezoides j; magnum |; unciform |. The cuneiform has a rather L-shaped external face, its ulnar face being strongly excavated in correspondence with the angular extremity of the ulna. This peculiarity is not seen in Hyracotkeriwm venticolum and Triplopus cuhitalis. The pisiform has two proximal facets, and is enlarged and thickened dis- tally; pressed inward, it reaches the scaphoid. The trapezium is a small €68 THE BEIDGER EPOCH. subdiscoid bone with convex outer face. The magnum is as broad as deep in front, where its surface is swollen; it is produced behind into a spatulate decurved hook. The unciform has a narrow sub-acute hook behind, with wide base. Measurements. M. Width of earpals of first row together 0.044 Width of lunare, outer face 016 Depth of lunare, outer face 020 Depth of cuneiform, outer face 020 Width of cuneiform, outer face 020 Length of pisiform, outer face 030 Depth distally, outer face 014 Width three earpals of second row 038 Width magnum, outer face 015 Depth magnum, outer face 014 Depth unciform, outer face 017 Width unciform, outer face 020 Length unciform, anteroposterior 021 Length magnum, anteroposterior 029 Total length of earpals 040 The metacarpals are quite slender. The first only is wanting ; the third is ratlier stouter than the others, while the fourth is considerably "the most slender. Its distal extremity is oblique, with prominent median teel, which is wanting on the superior aspect. The proximal facets of these bones are respectively (2d) 2, (3d) 2, (4th) 1, (.5th) 1. There is a short, shallow groove near the proximal end of No 3. The phalanges corresponding are lost in the specimen. Measurements. M. Length of fifth metacarpal 0.070 Estimated length of foot 187 Distal diameter of fifth metacarpal 012 Proximal diameter of metacarpal 007 Proximal diameter of fourth metacarpal 012 Proximal diameter of third metacarpal 017 Proximal diameter of second metacarpal 012 The above are taken on the articular faces transversely. The pelvis is perfectly preserved. The ischium is but little over half as long as the ilium, measuring from the middle of the acetabulum. The ilium is a triradiate bone, the superior or sacral plate rather shorter and wider than that forming the "crest," which is subsimilar to the pedun- cular portion. The border connecting the sacral plate with the crest is HYRACHYUS. 669 more than twice as long as the crest, and is gently concave. The crest truncates this and the inferior border of the ilium at right angles. The crest expands very slightly distally forward and downward. The ischio- pubic suture is a long one, and the obturator foramen a long oval ; the inferior pelvic elements do not form a transverse, but meet at an open angle. Measurements. M. Length ilium to sacral border 0.130 Length ilium to crest 180 Width crest 060 Width peduncle 030 Length ischium from middle of acetabulum 110 Width ischium posteriorly .080 Length obturator foramen 041 Width obturator foramen .' 034 Expanse of ischia above at middle 076 Femur. — The head projects inward on a well-marked neck. The great trochanter is strongly recurved and presents an anterior tuberosity as well It rises to an incurved apex much elevated above the head. The prominence of the front of the femur is continued into the front of the trochanter. The outer margin of the shaft is thin, and at a point two- fifths the length from the proximal end is produced into a low third trochanter, which is curved forward and thickened on the margin. The trochlea is well elevated, the inner margin a little the more so, and is narrow. It is continuous with the surface of the inner condyle, which is the shorter and more vertical ; the external is longer and divergent ; its terminal face is marked by two fossae, one in front of the other just out- side the distal end of the ridge bordering the trochlea. Little trochanter moderate. Meas^trements. M. Total length 0.285 Proximal Tvidth of head and trochanter 075 Width from front to edge third trochanter 050 Width jiist above condyles 035 Width of condyles 058 Chord of outer condyle and trochlea 060 The tibia has a broad prominent crest, which is remarkable in being deeply fissured longitudinally at its superior portion. The tendinous notch separates the outer portion of the crest from the spreading margin of the outer cotyloid face. The crest disappears at the proximal third, and the 670 THE BEIDGEE EPOCH. shaft becomes flattened in front and on the inner side The distal articular extremity is impressed by 1§ trochlese, the outer being completed by the fibula. The posterior tuberosity is more nearly median than usual, hence the inner margin of the inner trochlea is low posteriorly, and the inner malleolus has a considerable beveled inferior margin. The fibula has a slender shaft, but little compressed. The head is expanded fore and aft, and the malleolus is quite stout. Measurements. K. Length of tibia 0.244 Diameter from outer augle of head to inner angle of crest 065 Diameter distal end (greatest) 035 Diameter articular face, transverse 027 Diameter .articular face, fore and aft 026 Both hind feet are perfectly preserved. The calcaneum is rather elon- gate and compressed, the lower face truncate with two longitudinal bound- ing ridges, the outer of which is discontinued before reaching the heel The surface between them is striate grooved. The outer face is slightly concave. The astragaline facets are much expanded inward; the outer is transverse and strongly convex, and separated by a groove from the inner, which is longitudinal and nearly plane. The posterior edge of this and convexity of tlie outer facets are received into a transverse groove of the posterior part of the lower face of the astragalus. The cuboid facet is diagonal, and is bounded within by a third narrow facet for the astragalus. The asta-agalus has a strongly convex, deeply grooved trochlea; the con- vexity extends over 15H°. The trochlea is nearly in the vertical, a little oblique to the longitudinal axis of the foot. The exterior malleolar facet is well marked, and bounds a lateral fossa above. The neck of the astragalus is broad and not contracted, but not wider than the trochlea. Its navicular facet is wide and concave, the cuboid narrow, with a long angle behind. The cuboid is quite elongate, and with a narrow anterior face; it has a large posterior tuberosity not projecting much posteriorly. The navicular is flat, with a sigmoid proximal face, convex on the inner side, concave on the outer. It has the three cuneiform facets below, the inner anteroposterior. The entocuneiform is flat with anteroposterior plane, and apex directed back- ward, and considerably oblique facet for the second metatarsal. The meso- HTEACHYUS. 671 cuneiform is much the smaller, and brings the third metatarsus a short dis- tance proximad to the foui'th. The ectocune'iform is a little wider than deep. The metatarsals are three, and are rather slender. The two outer are equal in length, and the median but little wider proximally, the in- creased Avidth being more obvious distally. They have no proximal grooves, and the outer has a low outer tuberosity. The facets of the second row of tarsals are \ \ \. The phalanges, including- ungual, are 3, 3, 3. The prox- imal ones are longer than wide and contracted at the ends; the penultimate are still stouter in form. The ungues of middle line are symmetrical and broad, with the margin a segment of an ovoid, and slight contraction at the neck. The proximal articulation is bounded by a fossa on each side, which is in its turn isolated by the elongate process found in the tapir and in the horse. The margin is marked by radiating strise separated by grooves, of which the median is the most marked. The lateral ungues are contracted on the inner side, and only possess the proximal fossa and hook on the outer side. The median distal groove is well marked. ■ Measurements. M. Length of hind foot from heel 0.286 Length of calcaneum 053 Length of cuboid facet of calcaneum 024 Depth calcaneum behind 025 Width calcaneum at astragalus 035 Greatest axial length of astragalus 045 Width between trochlear crests astragalus 022 Length neck between trochlear crests, outer side .' 014 Width head 030 Width navicular 031 Length navicular at middle 010 Length cuboid 022 Depth do. outside 025 Length ectocnneiform in front 013 Width ectocuneiform in front 019 Width mesocuneiform iu fiont 019 Length mesocuneiform in front 003 Length entocuneiform at side 021 Depth entocuneiform at side 015 Length of metatarsiis ii 102 Length of metatarsus iii 107 Width of metatarsus ii proximally 016 Width of metatarsus iii proximally 020 Width of metatarsus ii distally ) within < 016 Width of metatarsus iii distallv . .. ) fossa t 025 672 THE BEIDGER EPOCH. M. Length median phalanges i 0.025 , Width median phalanges ii distally 015 Depth median phalanges iii distally 009 Length median phalanges ii 015 tength median phalanges unguis 029 Width of articular facet unguis 014 Width of neck of facet unguis '- 021 Width of greatest expanse facet unguis 029 Length phalanges of metatarsal ii 060 Length unguis of metatarsal ii 028 Width unguis (greatest) 018 Length metatarsus and phalanges iv 158 Restoration. — The following dimensions may be relied on as a basis for a restoration of this species: M. r head 0.220 vertebral column less tail 063 Length < I, equal 42.1 inches - 1.283 f of neural spines exposed 035 I of scapula 215 Height < of fore leg 692 [ total 31.05 inclusive 947 ' of hind leg 770 _. ,^ of elevation of ilium 135 Height < , total 29.7 inches 905 Depth of body at middle manubrium 255 Depthofbody at 15thrib 250 Allowance being made for the obliquity of the humerus, scapula, femur, and ilium, the elevation in life was — M. At the withers (26.6 inches) 8*2 At the rump - ~62 The size of this species was, then, that of a large sheep. Comparison of the skeleton with that of Tapirus rouUni. — For the oppor- tunity of making this comparison I am indebted to the Smithsonian Insti- tution, which possesses a skeleton of the above species of tapir from Ecua- dor, presented by Pi^esident Moreno. Cranium. — In addition to the generic characters mentioned at the com- mencement of this description, the H. eximius and T. roulini differ as follows: In H. eximius there is (1) a high sagittal crest which is wanting in T. rouUni, T. malayanus, and approximated in T. terrestris; (2) the crest of the squa- HYUAOHYUS. 673 mosal part of the zygoma is continuous with the lateral occipital crest, which is not the case in existing tapirs. Vertehrce. — (1) The arterial canal of the atlas is not isolated in front as in T. roulini, but notches the basis of the transverse process. (2) The axis is longer than in T. roulini. (3) The neural spines, and especially the metapophyses of the posterior dorsal vertebrae, are more elevated. (4) The ends of the centra of the lumbars are flatter and more depressed. (5) The diapophyses of the same are wider and longer and thinner, and the penulti- mate articulates with the last by an angular process, which is not the case in T. roulini. Scapula. — (1) This bone is equal in size to that of a T. roulini of con- siderably greater general dimensions, and is hence relatively larger. (2) The spine is not angulate as in that species, has a larger base, and larger elevated margin. (3) The neck is more contracted, and (4) the coracoid is not recurved as in T. roulini. (5) The sinus bounded below by the lat- ter is much "shallower, and not bordered above by a recurved hook of the margin. Humerus — (1) It is relatively smaller in ^. ea;mJM5. (2) The internal bicipital ridge of T. roulini is wanting. (3) The external condyle is much shorter, whence its border is nearer its trochlear rib. The radius has a narrower head, (1) the external articular plane being shortened. (2) The shaft is wider with a more acute longitudinal lateral ridge medially, and more rounded distal end. The ulna is (1) absolutely nearly as long as in T. roulini, being thus relatively longer. (2) It has three weak, longitudinal ridges on a convex outer face; in T roulini the external face is divided by a very prominent longitudinal angle from the radial cotylus, which spreads distally, sending one angle to the upper and another to the lower base of the distal epiphysis. Carpus. — This part is (1) absolutely and relatively smaller than in T. roulini. (2) The pisiform is more cylindroid distally. (3) The scaphoid is more produced backward on the inner side; the excavation of the inner side is more continued as a concavity of the outer side of the front. (4) The unciform has an acute tuberosity behind ; in T. roulini it is short, ver- tical, and obtuse. (5) The trapezoides has a shorter, wider, and more 43 0 674 THE BRIDGER EPOCH. swollen external face. (6) The pisiform is small and convex, instead of being larger and flat. The metacarpals (1) are absolutely and relatively smaller. (2) The inner (II) has a more oblique phalangeal articulation, which is short above and with the keel prolonged upward, instead of being as in T. roulini, distal only. The pelvis is distinguished by the much longer plate of the ilium whose extremity constitutes the crest. (1) The crest is also shorter, and more anterior. In T. roulini this plate does not so much exceed the sacral plate in length. (2) The pubes and ilia are not so horizontal, but meet at nearly a right angle, and (3) the ischiopubic common suture is considerably longer. (4) The obturator foramen is a more elongate oval. The femur is very similar to that of T. roulini, being no smaller in rel- ative size. (1) The great trochanter is wider fore and aft, and with margin more continued on the anterior aspect of the extremity of the shaft. (2) The third trochanter is neai-er the middle of the length. (3) The condylar surfaces are continuous with the rotular, not isolated as in T. roulini. The latter also (4) lacks the two fossse on the outer margin of the external seen in H. eximius. (5) The rotular groove is also narrower in the latter and not so deeply excavated as in T. roulini. The tibia is (1) reduced in size, and especially contracted distally; the relative widths of the ends are 6 cm : 3.5 ; in T. roulini 7.5 cm to 5. (2) The crest is more prominent and is deeply fissured by a groove, which is rep- resented by a shallow concavity in T. roulini. The groove (3) external to this is deeper. (4) The posterior inner tuberosity of the distal end is more median, hence the inner trochlear groove is further removed from the ante- rior inner malleolus, which has, therefore, a greater inner (not outer) extent. The tarsus (1) is generally longer and narrower, except in the case of the cuboid bone (2), which is shorter than in T. roulini. (3) The astragalus has a narrower neck, which, therefore, appears more on the inner side. (4) The facet for the cuboid is smaller. The inner tuberosity of the head is more prominent. (6) The calcaneum is more slender, with larger cuboid facet, especially posteriorly. The metatarsus is absolutelj^ nearly as long as in T. roulini, and, therefore, relatively longer and more slender. (2) The HYRACHYUS, 675 median (III) is nearly similar to the others in width; in the T. roulini, much larger than the lateral. The phalanges of the first cross series are more contracted distally. Thus the more important differences between the skeleton of the two species in addition to those pointed out under the head of the genus, are those of the ulna, the scapula, the lumbar vertebrse, the ilium, and the crest of the tibia. The scapula is more like that of Tapirus terrestris, while the ilium is approximated by that of T. malayanus among living species; its form leans toward the Equine series, and not to the Palseotheroid. The following measurements of the inferior dental series are derived from the specimen enumerated at the beginning of the description of this species as No. 2 : Length of last two superior molars 0.041 Length of last 019 Width of last 022 Length of inferior molar series 095 Length of premolars 040 Length of last molar 021 Width of last molar 013 Depth of ramus at first true molar 040 Hyrachyus agrarius Leidy. Hayden's Report Geol. Surv. Wyoming, 1871, p. 357. Proceed. Academy Phila., 1871, 229; 1. c. 1872, 19, 168 ; Hayden's Report Geol. Surv. Montana, 1872, 361. Hyrachyus agrestis Leidy. Hayden's Report Geol. Surv. Wyoming, 1871, 357. Lophiodon bairdianus Marsh, Amer. Jour. Sci. Arts, 1871, II p. 3. Hyrachyus implicatus Cope, Specimen 1, on some Eocene mammals, etc., Paleon- tological Bulletin No. 12, p. 5. This species is nearly abundant as the H. eximius, from which it is chiefly distinguished by its inferior size. None of the numerous specimens which I obtained in the Bridger Basin are complete, so that I refer to Leidy for a fuller description than I can furnish. A specimen represented by both maxillary teeth with most of the molars was, with a second and more per- fect specimen from the Washakie Basin, referred by me to a distinct species under the name implicatus. The second specimen represents a different species from the first, which is, I think, an E. agrarius, and I retain for it the new specific name then given. In H. agrarius the superior molars have the cingular cusp smaller than the anterior external lobe, and separated from it by a ridge. A ridge or rib projects into the median valley from the external lobe, forming a loop 676 THE BEIDGER EPOCH. on wearing. It is more developed in some specimens than others. There are no cingula on these molars excepting a weak one at the external base of the first true molar. The enamel is smooth. Measurements superior molars. M. Length of five molars 0.071 Length of three posterior molars 0470 Length of last molar 0159 Wiilthof last molar 0200 Width of penultimate molar 0210 Length of penultimate molar 0168 The measurements of a mandible of another specimen are rather smaller than those of Leidy's .type. Length of five posterior molars 071 Length of true molars 045 Diameters third premolar ^'^"**'"''I"'«^*"'"^ ^^^^ i transverse . 007 Diameters of secoml true molar ^■^'^*'^''°P°«*"''"^ "^^ ( transverse 010 Depth of ramus at second true molar 028 The first-named specimen came from Cottonwood Creek, and the sec- ond from Black's Fork of Green River, both in the Bridger Basin. Hyrachyus implicatus Cope. Paleontologie.ll Bulletin, No. 12. (On some Eocene Mammals, etc.), March 8, 1873, p. 5; Specimen No. 2. Annual Report U. S. Geol. Surv., of the Territories, 1872 (1873), p. 605, Spec. No. 2. Hy- racht/us crassidena, Scott, Spier, and Osborne. Paleontological Report Princeton Scientific Ex- pedi., 877, 1878, p. 52. Plate LVIII ; figs. G, 7. This tapiroid species as now defined is represented by an imperfect skull in my collection. The part preserved is one side of the face with all the superior molar teeth, with the right half of the mandible supporting all the teeth. The superciliary and other orbital borders of the right side are also preserved. The specimen agrees in its proportions, and in all the details, with the description given by Princeton paleontologists of their H. crassidens. The superior molar teeth have no external or internal cingula, but the an- terior and posterior are present excejit on the first premolar on the second and third premolars, and where there is no anterior cingulum. The premolars, ex- cept the first, have two uninterrupted cross-crests, the anterior of which is the longer, and curves round the internal extremity of the posterior ; to it in the fourth, and beyond it in the second and tliird. The cross-crests of the true HYRACHYUS. 677 molars are uninterrupted and regular. There is no tubercle between them, and the ridge from the external wall is not prominent. The anterior cingular cusp is low and is in contact with the base of the much higher anterior lobe. The second external lobe of the first true molar has a short vertical ridge near its apex. This ridge is almost as well developed as the anterior ridge on the premolars. The inferior molars are distinguished for the width of the anterior basal cingulum, and the large anteroposterior diameter of the second and third premolars. The diastema is also very short, measuring only three- fifths the length of the bases of the first three premolars, while it equals the latter measurement in the H. agrarius. The canine tooth is not much larger than the third incisor, is implanted close to it, and has an antero- superior direction. The mandibular ramus is not deep, and the symphysis is narrowed, strongly convex, and rather slK)rt. The infraorbital foramen opens above the posterior part of the third superior premolar. The orbit is entirely lateral, and its anteroposterior diameter is a little greater than its vertical. The superciliary border is rather thick, is somewhat prominent. There is no postorbital process, but the superciliary border curves round and passes with a trace of an angle into the anterior border of the temporal fossa, which for a short distance is transverse. The temporal ridges are weak in their ante- rior parts. The skull is broken off before their union into a sagittal crest. Measurements. M. Length of superior molar series — 0.085 Length of true molars 046 Length of penultimate 015 Width of penultimate 019 Length of inferior molar series 078 Length of inferior true molars 047 Length of penultimate 017 Width of penultimate Oil Width of last premolar 008 Length of last premolar 012 Depth of ramus at last premolar 0235 Length of diastema 019 Length of bases of three incisors 018 From the Bridgfer Eocene of the Washakie Basin near South Bitter ■Oreek, Wyoming: 678 THE BEIDGEE FAUNA. TRIPLOPODID^. Cope, American Naturalist, 1881, April (March 25), p. 340. But one genus of tliis family is known at present, but the number will probably be increased when the structure of the feet of various imperfectly known species is ascertained. TRIPLOPUS Cope. American Naturalist, 1880, p. 383 (April 27.) 14 3 Dental formula, I. 1; C. -; Pm. ; -; M. ^; a considerable diastema 1 4 3 anterior to tlie first premolar. Molars with only two vertical external ridges, viz: the anterior cingular and the approximated median of the an- terior crescent. Transverse crests two, uninterrupted and rather oblique ; a ? third and short crest on the posterior base of the first true molar. Premo- lars different from molars, the third and fourth with two transverse crests. Inferior molars with two transverse crests, as in Lophiodon, the last without heel. An ossified inferior wall of the meatus auditorius externus. Posttym- panic and paroccipital processes distinct from each other. No postorbital arch. Postparietal and mastoid foramina preserved ; the latter large. Cervical vertebrae rather long; axis with subcylindric odontoid process. Scapula with small coronoid process. Great tuberosity of humerus long, curved. No trochlear crest on condyles of humerus ; epicondyles rudi- mental. Ulna and radius distinct throughout their length ; ulnar articula- tion with carpus, small. Trapezoid bone of carpus with a facet for the trapezium. Unciform with two inferior facets. Metacarpals three principal ones, and one, the fifth, rudimental ; the distal extremities of the second and fifth opposite ; the third a little longer. The dentition of this genus is nearly that of Hyracliyus. The only exception is the possible third transverse crest of the first true molars.^ The other portions of the skeleton known are also much like those of Hyrachyus, with the exception of the number of digits of the anterior foot. The en- ' This point is farther considered in the description of the species. TRIPLOPUS. 679 tirely rudimental character of the fifth metacarpal, which, with its digit, is so well developed in Hyracliyus, places Triplopus in another family, and in another line of descent. I think that it must be regarded as one of the forms of the series connecting the lophiodonts with the rhinoceroses. The fourth digit (the fifth) was retained by the earliest type of rhinoceros in Europe, the genus AceratJieriwn, but in America it appears to have been lost earlier. None of the American rhinoceroses of the Lower Miocene, of the genus Coenopus Cope, present it, and in the present genus we have an ancestral type of the Eocene period, in which the last digit is already lost. The premolars of different structure from the true molars exclude this genus from the Rhinocerontidce, and with the character of the feet place it between that family and the LophiodontidoB. As yet but one species of Triplopus is certainly known, but a second is placed in it provisionally. Teiplopus cubitalis Cope. American Naturalist, 1880, p. 383. Proceedings Amer. Philos. Soc, 1881, p. 383. Plates LVa, figs. 10-12 : LVIo. This species is represented by a nearly entire skuH with lower jaw; most of the cervical vertebrae; a left anterior limb nearly complete; a part of the left scapula, and a part of the right anterior limb ; all belonging to one animal. The specimen was not quite adult, as the last superior molar is just protruding its crown through the maxillary wall, and the last two superior milk premolars still remain in place, much worn and closely pressed by the overlying successional teeth. The cranium is peculiar in its wide orbital region, and short compressed muzzle; the latter is damaged in the specimen, so that the form of the nasal bones cannot be determined except at their proximal portions. The interorb- ital space is plane in both directions, and rises very gently posteriorly. The sagittal crest is narrow and low, until above the meatus auditorius, where it rises Above the posttympanic process it bifurcates, and each rounded lateral lobe extends posteriorly to a point above the occipital condyles. Viewed from above the head is wide between the zygomatic fossse, and at the posterior premaxillary teeth. The top of the muzzle narrows rapidly 680 - THE BEIDOEE FAUNA. above the latter, but does not contract below until the first premolar is reached. The zygomatic arch is not convex along- its middle, and incloses a narrow fossa. The superciliary border is prominent, and nearly straight, and is bounded by a notch behind. The squamoso-occipital ridge is well marked. The posttympanic process is shorter than the paroccipital, and is separated from it by an open shallow groove, which is probably bottomed by the mastoid bone. The paroccipital process is much narrowed below and is turned a little outwards. There are two closely adjacent tubercles on the anterior border of the orbit, probably on the lachrymal bone. Foramina. — Only a few of these are well preserved; among the lost is the/ infraorhitale. There are two postparietal foramina on one side, and one on the other, above the point of origin of the zygomatic process of the squamosal bone; and one in the usual posterior position. The postsqua- mosal has the same anterior position as the anterior postparietals, being immediately below them; I cannot discover whether there is a posterior one or not, owing to injuries to the specimen. There is a))parently a fissure- like one on the parieto-squamosal suture posteriorly. The mastoid is quite large, expanding downwards and outwards; it is not so large as in a tapir, but much exceeds that in Hyrachym eximkis. The meatus auditorius externus is large, and occupies only the posterior part of the space between the postglenoid and posttympanic processes. It is inclosed anteriorly and below by the border of a wide element which may be tympanic. It in- closes the petrous bone below in a bulla; as, however, the inner portion of the best preserved one is broken away, I cannot speak of its relations to the basioccipital bone. The foramen lacerum x>osterius is reduced to a jugular and perhaps another connected foramen by the close apposition of the pe- trous bone to the basioccipital for a considerable distance. The region of the/ I. medkis is injured. Postei'ior to the/ I. poster kis is a foramen oppo- site the base of the paroccipital process, anterior to the usual position of the / condyloideum. Mandible. — The angle of the lower jaw is produced posteriorly, as in some species' of Hijrachyus : cfr., fig. 1, pi. LYI a, and fig. 2, pi. LIII. The coronoid process is long and is curved backwards to above the jDOSte- ri(n- border of the condyle. There is no tuberosity behind the condyle. TRIPLOPUS. . 681 The sympliysis is quite contracted and is short. The mental foramen is below the middle of the inferior diastema. The ramus is compressed and -at the same time strong. Deniition. — As the deciduous third and fourth premolar teeth, in a worn condition, remained in the maxillary bone, I removed them from one side, thus displaying the crowns of the coiresponding permanent teeth. The first premolar may belong to the permanent dentition; the second is the deciduous. The former has two roots. The crown is cutting for a short distance anteriorly, but posteriorly it expands into a heel, much less de- veloped than the internal lobe of the succeeding teeth The crowns of the third and fourth premolars differ externally, as well as in their crests, from those of the true molars. The median-anterior and cingular vertical ridges are not so prominent as in the latter. The external crest is not divided into two by the notch in its grinding face. The anterior cross-crest, at its inner or distal extremity, is turned shortly backwards and then inwards, giving a "pot-hook" outline to the triturating surface. The fourth decid- uous premolar presents a peculiar character already ascribed to the first true molar. This consists of a crest running parallel with the posterior transverse crest and close to it, along its posterior side It forms the liorder of the tooth for a short distance, but as its direction is slightly obliquely forwards as well as outwards, the posterior cingulum appears for a very short distance. The first true molar is subquadrate in outline. The anterior trans- averse crest commences at the middle anterior ridge, and is first transverse, then directed a little obliquely backwards. The second crest commences at the apex of the posterior external crescent, leaving a wide posterior marginal fossa. Its internal extremity is broken off. Posterior to, and in contact \yith it, the posterior cingulum rises in a crest, which occupies the internal half only of the border. Its inner border is imperiect. It appears to me to be probable that the normal posterior crest is turned posteriorly on itself so as to give the "pot-hook" shape seen in the anterior crest of the fourth permanent premolar. The corresponding accessory crest in the fourth temjDorary premolar appears to have been distinct at its internal ex- tremity. The second true molar has a more oblique posterior external crest, and the posterior internal is oblique and simple. It has narrow ante- 682 THE BEIDGER FAUNA. rior and posterior basal cingula. There is no tubercle between the inner bases of the transverse ci'ests of this or the last true molar. The latter is characterized by the rudimental character of the posterior external crescent crest, which is shortened like that of Hyrachyus. The transverse crests are curved backwards; the posterior is short and simple. The canines are small, and are directed forwards. The extremity of the muzzle being broken, the relation of the incisors cannot be stated, but there was not probably any precanine diastema. An incisor preserved has the crown transversely expanded, and rather oblique. The third and fourth inferior premolars are the deciduous ones, and are both three-lobed, but differ in the forms of the anterior lobe. In the third, it is narrow and incurved, as in the corresponding permanent teeth of some Artiodactyla. The transverse crests of the true molars are rather oblique, running forwards as well as outwards. Their external extremities are bent at right angles, and there results a short descending crest running forwards and inwards; the anterior one turns inwards again, forming a transverse anterior ledge. No cingula on internal or external b4ses of crown; a rudimental posterior one. Measurements of cranium. Length from front of canine tooth to end of occipital condyles 128 Length from same to postglenoid process .096 Length from same to end of last molar 069 Length from same to first premolar 015 Length from same to line of front of orbit 044 Width between superciliary borders 046 Width of zygomata at orbits '. 064 Width of brain-case at glenoid surface 048 Width of occipital condyles 023 Width of basiocoipital bone between ossa petrosa 006 Distance between postglenoid and post-tympanic processes 014 Depth of occiput behind 033 Depth of mandible from condyle 040 Depth of mandibular ramus at third premolar 014 Depth at diastema (axial) 009 Least width of symphysis Oil Diameter crown third permanent premolar ^ anteroposterior 007 (transverse .005 Anteroposterior diameter cro wu first premolar 0045 Diameters crown first true molar 1''^"'^™!"'^*''"°"' ^^" c transverse 012 Diameters crown second inferior true molar \ anteroposterior Oil ( transverse 0075 Diameter of root of inferior canine near crown 0035 TRIPLOPGS. 683 Vertebrce. — The atlas is about as long relatively as that of the horse. Its transverse processes have moi'e anteroposterior than transverse extent. The summit of the neural arch has a median ridge separating two grooves. The inferior surface of the centrum has a nearly median, obtuse hypapo- physis The axial facets are well separated below. The vertebrarterial canal pierces the base of the transverse process behind and below, and notches it deeply anteriorly. Above this notch the usual perforation of the arch is present. The axis is not relatively quite so long as that of the horse; it is a little longer than in Hyrachyus eximius, but ratlier shorter than in Hyracodon arcidens (PI. CII, Fig. 7). The atlantal facets are spread well apart, and the articulating surface of the odontoid does not connect with them. The latter is rather long, is obtuse, and slightly recurved; it has no raised borders. Between the atlantal faces the inferior surface is plane. Posterior to this the middle line bears a prominent keel. The dia- pophyses are long, narrow, and recurved, and each is pierced at the base by the vertebrartei'ial canal. The posterior articular face is but little con- cave, and a little oblique, and is a little wider than long. The succeeding cervicals regularly diminish in length, and become more strongly opisthocoelous, the seventh having quite a ball in front. The sixth has a slender diapophysis directed posteriorly, and quite distinct from the wide and long parapophysis which is directed downwards and out- wards. The posterior angle of the latter extends as far back as the cen- trum. The seventh has only a flat transverse diapophysis. The first dorsal has a very stout diapophysis excavated below for the rib tubercle. The diapophyses of the third and fourth dorsals are not so stout. The capitular fossae are large. The centra of the anterior dorsals are flattened below ; they are concealed in part by the matrix in this specimen. The neural spine of the sixth cervical is narrow, and is directed forwards. That of the seventh is vertical, and narrows rapidly from a base which is rather wide anteropostexiorly. The spines of the dorsals are wider, and are directed gently posteriorly ; they are probably long, judging from the size of their bases. Measurements of vertebrce. M. Length centrum of atlas on side 027 Length centrnm of atlas below 010 <384 THE BRIDGEK FAUNA. Width centrum of atlas below posteriorly 030 Width transverse process of atlas flO Vertical diameter neural and odontoid canal 01.) Length axis to odontoid process 033 Length odontoid process 007 I ( with hypapophy sis 012 Diam. centrum behind ? ^'"''l'*"*' \ without hy papophysis 009 ' transverse 0115 Length of centrum of fifth cervical 030 Length of centrum of seventh 01/ Length of centrum of second dorsal 014 Anteroposterior diameter of base of neural spine of second dorsal 010 Expanse of head and tubercle of first rib 012 Fore limb. — The greater part of the blade of the scapula is lost. The neck is stout, and the coracoid is a short aliform process. The humerus is moderately robust, most so proximally. The greater tuberosity is a strongly incurved crest, with truncate summit, which is a little elevated above the plane of the head, from which it rises rather abruptly. The bicipital ridges are not strong nor prominent. The olecranar fossa is deeper than the coronoid fossa, and they communicate by perforation. The inner part of the condyle is the largest, and forms an acute angle with the interior «picondylar surface. The exterior part of the condyle is divided by an oblique angle of the surface separating an external beveled band of the same, which narrows to extinctiou on the posterior side. As compared with the humerus of Hijrachyus eximius, that of Triplopus citbitalis is very similar, ditfering mainly in two points at the distal extremity. The olecranar fossa is smaller and is less excavated, and its lateral bounding ridges are of unequal elevation ; in T. cubitalis they are equal. The ulna and radius are more than one-fourth longer than those of H. eximius. Although they are entirely distinct throughout, the ulna is quite slender anterior to the proximal third. The shaft is much more slender than that of Hyrachyus eximius. The olecranon is compressed, deep, and truncate behind. The distal epiphysis is remarkable for its length, being twice as long as that of the radius. The head of the radius is subequally divided by fossaj, the external being the shallower. The inferior or ulnar facet is regularly and gently convex downwards, and is bounded behind by a roughened ridge, which near the external border turns backwards to the humeral border. The shaft of the radius is robust and flattened. The TEIPLOPUS. 685 carpal facet of the radius is contracted, and has three times the superficial area of that of the ulna. The scapholunac dividing ridge is present, but is very low. The scaphoid face is the more excavated, and then rolls back- wards, forming a very nan-ow posterior facet, which is narrower than that found in the species of AncMtherium. There is no distinct fossa on its inner or posterior border, as in many ungulates. The trapezium and scaphoid are the only bones of the carpus which are wanting Tlie latter is pi'obably wider than long or deep, wliile both the lunar and cunei- form are longer than wide. The cuneiform has not its external border excavated ; its proximal surface is oblique and continuous, tlie ulnar and pisiform facets being in line. The pisiform is large, and is enlarged dis- tally ; its proximal facets are equal. The exposed face of the trapezoides is rather larger than that of the magnum, and is nearly as large as its own face of contact with the latter. The magnum has the usual great antei'O- posterior extension, with elevated posterior convexity applied to the fossa of the lunar. Its posterior process is long, nearly equal to the rest of the bone, and is depressed and flattened distally. The metacarpal facet is very concave. The unciform's anterior or exposed face is a little longer than wide. Its two proximal facets are about equal. It is about as deep as wide, and extends half its length distad to the magnum. Its posterior pro- cess is rather narrow ; it is narrow and abruptly decurved Distally, the facet for the fifth metacarpal is well marked, and has about half the area of that for the fourth metacarpal. The functional metacarpals are of moderate length as compared with the elongation of the ulnoradius. The third is largely in contact proximally with the unciform as well as with the magnum. The condyles are stout, aiid each is laterally impressed by a fossa. The second and fourth have chiefly lateral presentation, but are not much narrower in the shaft than the median metacarpal. The first phalange of the lateral digit is a little shorter tlian that of the median, while the seconds are of equal length. Ilie extrerait}^ of the second digit reaches the proximal third of the length of the median ungual phalange. The fissure of the ungual phalange reaches the middle of its length. The fifth metatarsal is proximally rather stout ; but it soon contracts to a thin rounded extremity at only one-fifth the length of the fourth. 686 THE BlUDGER FAUNA. Measurements of/ore limb. It. Anteroposterior diameter of cotyloid cavity of scapula 015 Diameter of head of humerus ^ *''*°^^'*'"'' ^^^ t anteropostenor 019 Diameter -with greater tuberosity 030 Length of humerus on outer side 110 Diameter humerus at epicondyles^*'^'*"*'*'®''*® ^'^^ I anteroposterior externally 015 Length of ulna 165 Length of radius ^ 141 Depth of olecranon, distally 015 Width of ulna at coronoid 015 Width of ulna at carpal facet (greatest) 007 Width of radius at head 016 Width of radius at carpal facets 014 Width of radius at widest point distally 016 Length of carpus at magnum 015 Length of carpus at unciform 018 Length of lunar 010 Depth of lunar , Oil Length of magnum 005 Depth of magnum 017 Leugth unciform i 009 Width unciform 009 Depth unciform ( total) 014 Depth unciform of inferior facets 007 Length of third metacarpal 068 Proximal diameter third metacarpal ^^"*«''°P°«*«"*"" ''^ c transverse 008 Length of fifth metacarpal 012 Length of median series of phalanges 027 Length of first median phalange 010 Width of first median phalange, proximally 008 Length of second phalange 006 5 proximally 0070 medially 0055 greatest 007 The body of this animal was about the size of that of a red fox. The legs were more slender or elevated, and the head of course was shorter and thick. The unique specimen on which our knowledge of this species rests was cut from a block of calcareous sandstone of the bed of the Washakie basin of the Bridger Epoch, near South Bitter Creek, Wyoming Territory. The bones are generally in the relation of the position in which the animal died. The neck is depressed and the left fore leg raised so as to be in contact with it, and the head is I'aised so as to clear the left wrist. TRIPLOPUS. 687 Triplopus amarorum Cope. Proceeds. Amer. Philos. Soc, 1881, p. 389. Plate LV, figs. 6-9, and LVIII a, fig. 2. The characters of the fore foot of this species being unknown, it is not possible to determine its generic position. It has, however, one of the well- marked characteristics of the genus Triplopus, in the osseous inclosure of the meatus auditorius externus, through the ossification of the external pro- longation of the otic bulla and tympanic cartilage. I cannot, therefore, refer it to HyracJiyus. It is represented by a skull from which a large part of both maxillary bones and the maudible have been lost, and which is accompanied by parts of the ulna and radius, parts of the ilium, a femur, and tibia, and nearly all of the posterior foot of the right side. The postexior parts of both max- illary bones remain, and they suppoi't each, the last superior molar tooth from which the external wall has been broken away. The portions of mo- lars remaining exhibit characters which lead me to suspect that the species does not belong to Hyrachyus. The anterior cross-crest of the molar pre- served, is lobate, resembling the same ridge in the species of Anchitheriuni. The posterior cross-crest is uninterrupted. If this species possesses affinity with Anchitherium. it will perhaps possess three digits of the man us, in which case it will be referred to the Triplopidce, in harmony with the indication furnished by the ear structure. The Triplopus amarorum is much larger than the T. cubitalis, equaling the Hyracodon nehrascensis. It differs from the T. cubiialis in the stronger temporal ridges and more elevated sagittal crest; also in the shorter post- tympanic process. The internal lobes of the last superior molar are con- nected by a basal ledge, not found in the T cubitalis. The interorbital space is wide and flat, and is most expanded at the postorbital angles. From this point the face contracts rapidly forward. From the same angle it contracts abruptly posteriorly to the rather narrow brain case. The anterior temporal ridges ai-e nearly transverse near the postorbital jirocesses, and then converge more gradually, uniting opposite the posterior inferior border of the zygomatic fossa. The elevated sagittal crest diverges into 688 THE BKIDGER FAFNA. two lateral supraoccipital crests, which contract as they descend, and con- tinue to the extremities of the post-tympanic processes. Although the post- orbital angles are prominent, they cannot be called processes. The paroc- cipital processes are large, and are directed vertically downwards. They are separated by the usual concavity from the occipital condyles. The posttympanics are very short, forming only an angle projecting downwards at the anterior base of the paroccipitals, from which they are only separated by a notch. The inferior side of the tympanic bone is flat near the meatus, but opposite the stylomastoid fossa its posterior border is turned forwards,, and is produced into a well-marked process. It incloses a groove in front of it, which is continuous with the pterygoid fossa. The petrous bone is not inflated, and its inferior surface is divided into two longitudinal ridges. The inner is the less prominent, and is in close contact with the basioccipi- tal. The postglenoid processes are robust and obtuse. The basioccipital is excavated in front of each of the condyles. The inferior surface is nearly flat, with a slight median keel. The pterygoid fossa is Avell defined, and is long and narrow. The posterior nareal trough is elongate, the descending pterygoid processes of the sphenoid originating as far back as the apex of the OS petrosum. This species is especially characterized by the presence of an acute keel like ridge, which extends horizontally above the foi'amina spheno- orbitale and opticum, and turns upwards anterior to the latter, terminating a half inch below the inferior base of the postorbital process. All the fora- mina are below it, but there is a fossa above it, opposite the interspace be- tween the / opticum and / sphenoorhitale. A supraorbital foramen pierces the frontal bone a quarter of an inch within the superciliary border. There are five or six postparietal foramina, two of which are nearly on the squamosal suture There is a postsqua- mosal foramen, and also a not very small supraglenoid foramen. There is a small foramen anterior to the optic, and in line with the posterior part of the postfrontal angle. The foramen opticum is large, and is 10™". in front of the / sphenoorhitale. The latter is separated by a lamina from the large and vertically oval / rotundum. The latter is joined by the large alisphenoid canal, whose posterior orifice is as large as the foramen ovale. The latter is large, and is well separated from the / lacermn anterius. The / / lac.era TRIPLOPUS. 089 are well closed up, the posterius being reduced to what is probably the jugu- lar foramen. The / condyloideum is large, and is an anteroposteriorly placed oval Its anterior extremity is opposite to and well separated from the / jugulare. The nasal bones are spread out posteriorly, and their posterior extremi- ties are truncate. The coronal suture passes downwards at the narrowest part of the cranium behind the postfrontal angles. The squamosal bone does not reach the frontal. The parietal does not extend so far posteriorly as the lateral occipital crests, except near the squamosal. The characters of the last superior molars have already been mentioned. The posterior transvei-se crest is uninterrupted, but the anterior consists of closely united internal and median lobes. The division is marked on the posterior side, and on the edge of the crest; the anterior face is plane. The longitudinal external crest sends a strong protuberance into the head of the valley, which is grooved on its surface. There is a strong anterior basal cingulum which rises to an anterior cusp. On numerous surfaces the enamel is slightly rugose. The inferior canine teeth are in continuous series with the incisors, and are slightly larger than they. Measurements of skull. M. Length from line connecting anterior borders of orbits to occipital crest 0. 132 Length from line connecting posterior borders of orbits to occipital crest 100 Width between postorbital angles 100 Width between anterior borders of orbits 076 Elevation of occiput 065 Width between mastoid ridges 065 Width between ossa petrosa at middle 018 0200 0205 anteroposterior 0200 transverse 0150 Diameters third superior true molar ^ anteroposterior . ( transverse Diameters second superior true molar (base) \ ( The portion of ilium remaining exhibits a rather narrow neck and a concave external face. A fragment of the femur shows a prominent third trochanter, with an obtusely rounded apex. The distal part of the fibula is not coossified with the tibia. Its shaft is exceedingly slender. The angles bounding the trochlear grooves and ridges of the tibia are of subequal lengths. The median ridge is rather wide; the inner malleolus is narrow, has no distal facets and no distinct tendinous grooves externally. 44 c 690 THE ERIDGEE FAUNA. The posterior foot is both relative!}- and absolutely smaller than that of Hyrachyus eximius. The trochlea of the astragalus is narrower and more deeply grooved. The crests are obtuse, and not so narrowed as in Anchi- therium hairdi, nor are the malleolar facets of the astragalus so sharply defined as in the latter species. The external ligamentous fossa is, however, deep, and is bounded anteriorly by a low trihedral tuberosity not found in the A. bairdi. The head of the astragalus is not sessile as in A. bairdi, and has rather the proportions of E. eximius. The cuboid facet is a bevel of the external side of the distal extremity, as in H. eximius, and is not on a pro- duced ledge, as in A. bairdi. The internal tuberosity of the head is not as much developed as in either of the species named. The navicular face of the asti-agalus is horizontally divided by a shallow ligamentous fossa. The calcanenm is much like that of Hyrachyus eximius. The cuboid face is less oblique than in that species, in the anteroposterior direction, and is less crescentic in outline than in A. bairdi. The sustentaculum is rather more extended transversely than in H. eximius, but resembles that species more than the A. bairdi, in wanting the deep groove at its base on the inferior side, which cuts it off from the rest of the calcaneum. The remainder of the inferior surface is flat, and not grooved for a tendon as in H. eximius. The remainder of the tarsus includes the usual five bones, the three cuneiforms being present. They are in general a good deal like the corre- sponding bone of Hyrachyus eximius. The navicular differs in having a low transverse ridge on its proximal face, which fits the groove of the astragalus already mentioned. The hook of the cuboid is large. The external (ante- rior) face of the mesocuneiform has one-third the superficial area of the anterior face of the ectocuneiform. The entocuneiform is rather large, and is flat and subsemicircular. Its position is externo-posterior. The ecto- cuneiform presents facets to both the second and fourth metatarsals, that with the latter the largest. The distal halves of the metatarsals are lost. At their proximal portions they are of subequal width, as in Hyrachyus ex- imius, but the lateral ones are rather narrower at the middles of the shafts. Measurements. M. Width of distal extremity of tibia 029 Width of astrasralar face of tibia 019 TKIPLOPUS. 691 Length of inner malleolus - 007 Length of astragalus on inner side 030 Depth of trochlea on inner side 017 Depth of head on inner side 0145 Width of trochlea 015 Width of navicular facet 0195 Length of head from inner crest of trochlea ._. 005 Length of calcaneum - 058 Length of free part of calcaneum 037 Distal depth of the calcaneum 016 Diameters cuboid face calcaneum ^*"t«'-°P°«t«"°'' °J*^ < transverse 0145 Length of navicular 008 Length of cuboid - 0145 Transverse proximal width of three metatarsals 027 Diameters of second metatarsal < ^ _., c transverse W7 Antero-posterior diameter of third metatarsal 0145 Diameters of fourth metatarsal < ^ „,„ ( transverse "i* This species was obtained in 1873 from the bad lands of South Bittei' Creek, Wyoming, from the Washakie basin of the Bridger formation. The locahty is the same as that which furnished the Triplopus cuUtalis, the Achcmodon insolens, etc. HYRACODONTID^. This family, which I characterized in 1879, includes, so far as yet known, the single genus Hi/racodon, which is found in the Oligocene White River formation of North America. According to Marsh, the digits of this genus number three on both anterior and posterior limbs. It has a full series of incisor teeth in both jaws. RHINOCERIDiE. This extensive family has left representatives in all parts of the North- ern Hemisphere, and species still exist in the Old World. From the fol- lowing table the range of variation of its genera can be readily seen: I. Four anterior digits. lucisors f ; canine f ; no horn ; postt ympanic bone distinct Aceratherium. II. Three anterior digits. a. Posttympanic process not coossifled with postglenoid. Incisors f ; canines f ; no dermal horn Cwnopus. Incisors \; canines ^; no dermal horn Aphelops. Incisors f ; canines ^; no dermal horn Peraeeras. 692 ' THE EOCENE FAUNA. Incisors \; canines f; a tuberosity for a dermal horn on each nasal bone. Diceratherium. Incisors \; canines f ; a median dermal nasal horn Ceratorhinus, Incisors f ; canines f • - - Zalabis. Incisors^; caniues ^; dermal horn median; no osseous nasal septum Atelodus, aa. Posttympanic process coosified with postglenoid; Incisors \; canine ^; dermal horu median; uasal septum not ossified Bhinocerus. Incisors g ; canine ^ ; dermal horu median; nasal septum ossified Ccelodonta. It can readily be seen that the genera above defined form a graduated series, the steps of which are measured principally by successive modifica- tions of four different parts of the skeleton. These are, first, the reduction of the number of the toes of the anterior foot; second, the reduction in the number and development of the canine and incisor teeth; third, the degree of closure of the meatus auditorius externus below; and, fourth, in the de- velopment of the dermal horns of the nose and its supports. While these characters have that tangible and measurable quantity which renders them available for generic diagnosis, there are others which possess a similar significance, and which I have noticed in an article published in the Bulletin of the U. S. Geological Survey of the Territories for September, 1879. This series may be represented iu genealogical relation as follows:^ Coelodonta, / Bhinocerus. Atelodus. \ Ceratorhinus. Peracerds. Aphelops. Zalabis. Ccenopus. Diceratherium. The early type, which corresponds most nearly with Ccenopus, and which pi-eceded both it and the Aceratlieria in time, is the genus Triplopus Cope, which has left a species in the Upper Bridger of Wyoming. Here the incisors are probably 3 and the canines \. This formula is that of the Eocene tapirs, where the normal numbers | \ prevail. Triplopus further ' See American Naturalist, 1880, p. 611. PEEISSODACTYLA. 693 <3iffers in the primitive condition of the premolars above, which, as in the Lophiodontidce, differ from the molars in their greater simplicity. Thus it is probable that tapiroids, probably Lophiodontidoe, gave origin to the Bkino- •ceridce, as Marsh has suggested. And it is further altogether probable that the general type of dentition presented by the Rhinoceridce, Lojjhiodontidce, etc., which I have named the palseotheriodont, took its origin from the type -which is intermediate between it and the bunodont, viz, the symborodont, iis I have pointed out in an essay on this subject. The first appearance of dermal horns was apparently in a pair placed transversely on the nasal bones, in species of Eocene Lophiodontidce of the genus Colonoceras. The same character has been observed by Marsh in species of the Lower Miocene, which probably belong to the true Rhino- ceridce, and which he has called Diceratherium. This genus appears to liave terminated the line exhibiting this structure, and the family in North America remained without horn. As we have seen, the types possessing the median horn arose in Europe, in the Ceratorhinus schleiermacheri of the Middle Miocene, and still survives. It may be observed, in conclusion, that a successive increase of size in the species of this line has taken place in North America with the advance •of geologic time. Thus, their probable ancestors of the genus Triplopus were the least of all. The Coenopoda of the White River formation were larger; the oldest, C. mite, being the smallest. The Aphelopes of the Loup River or Upper Miocene formation were all larger, and were nearly equal to the large existing species. TAPIRID^. The genera of this family are not numerous as yet. The oldest, Des- matotherium, appears in the Middle Eocene (Bridger), and Tapirus is first found in the Upper Miocene (Epplesheim). The recent species of the family belong to Tapirus L., and Elasmognatlms (Gill). A small species, the Tapirulus hyracinus Grerv., is from a bed at Perreal, France, which Pictet has identified with the gypsum of Paris (Oligocene). It is some- times referred to this family, but is not sufficiently well known to determine its position. In America a genus which has not yet been distinguished from Tapirus is found in the Miocenes. 694 THE WASATCH PERIOD. The three genera are distinguished as follows: Two superior i^remolars different from true molars Desmatotherium. One superior premolar different from true molars; no heel of third inferior molar; nasal septum cartilaginous Tapinis. Like Tapirus, but nasal septum osseous Elasmognathus. CHALICOTHERIID^. Gill; Cope, American Naturalist, 1881, p. 340. This family had numerous representatives during Eocene time, and a few species of Chalicotherium extended into Miocene time. The boundaries which separate the family from the Lophiodontidce on the one hand and the Menodontidce on the other are not always easy to determine. From the former the symmetrically developed external Vs of the superior molars, and the double Vs of the inferior molars, distinguish it. Yet in Pachynolophus the external Vs are not so well distinguished as in other Chalicotheriidce ; and the anterior cingular cusp produces a part of the asymmetry found in the Lophiodontidce. The character of the double inner cusps of the superior premolars which distinguish the Menodontidce is only applicable to the last premolar in Diplacodqn of the latter, while a trace of the additional cusp of this tooth is found in the Chalicotheroid Nestoritherium. In using the following table it must be borne in mind that the number of the toes has been determined in a very few of the genera. Should any of them prove to have but three digits on the anterior foot, such genera must be referred to a new family intermediate between this one and the Paloeotheriidce. I. Internal cones of superior molars separate from external lobes. A. External tubercles of superior molars separated externally by a conic cusp. Fourth inferior premolar like flrst true molar Ectocion. AA. External Vs of superior molars separated by an external ridge. a. Incisoi's present. /3. No diastema in front of second inferior premolar. Second premolar without inner lobe; last molar with one inner cone.. .Leurocephalus. Second premolar with inner cone; last superior molar with one inner cone. . Palceosyops. Second premolar with inner cone ; last superior molar with two inner cones . . Limnohyus. /5/3. A diastema in front of second inferior premolar. Two inner cones of last superior mola v , . Lambdotherium, aa. Incisors absent from both jaws. Last superior molar with one internal cone Nestoritherium. II. One or both internal cusps of superior molars united with the external lobes by cross-crests. CHALICOTHERIID^. 695 a. External cusps of superior molars more or less conic. An antero-external cingular cusp Pachynolophus. aa. External lobes of superior molars, inflected Vs. /9. No cresceutic inner lobes. No intermediate lobes ... Chalicotherium. The following regions have thus far furnished species of the above- mentioned genera: Europe — Pachynolophus, Chalicotherium. North America — Ectocion, Leurocephalus, Palceosi/ops, Limnohyus, Lami- dotherium. Asia — Nestoritherium. Of the American genera, Leurocephalus S. S. and 0. has been found by the Princeton Exploring Expedition of 1877 in the Bridger formation, but I have not met with it myself Ectocion Cope is known from a single species found in the Wasatch formation of Wyoming. ECTOCION Cope. American Naturalist, June (May 20), 1882, p. 522. Superior molars supporting eight cusps, viz, two internal, two interme- diate, and two principal external, together with two which arise from the external cingulum — one opposite the space between the principal external cusps and one at the anterior external angle of the crown. Fourth supe- rior premolar with two external and one internal cusp. The inferior molars supporting four alternating cusps, which are connected by oblique ridges, thus forming one V and more or less of a second anterior one. Fourth premolar with two posterior cusps. Third premolar with one posterior cusp. Skeleton unknown. Until the feet of this genus are known, it will not be possible to locate it with certainty. Its dental characters have considerable resemblance to those of Protogonia, and should the feet have the characters of the Condyl- arthra, its position will be near that genus. It is distinguished from Proto- gonia by the two-lobed fourth superior premolar, and from Phenacodus by the Vs of the inferior molars. The chai-acters of the molars are especially interesting as displaying the type which no doubt gave origin to the prevalent type of the Peri^so- 696 THE WASATCH FAUlirA. dadyle dentition, and demonstrates the correctness of the position which I assumed in the year 1874 on this subject. This was, in brief, that the lopho- dont type of molar has been derived from the bunodont by confluence of tubercles. In the family of the ClialicotlieriidcE the genus Pachynolophus exhibits the transverse cross-crests and external Vs characteristic of so many genera of the order. In Lamhdotherium these crests are partly broken up, and in Palceosyops entirely so. In all of these genera the external Vs are complete, though little indented in FachynoIojyJius. But in Edocion these also are broken up into a median cusjj representing the apex, and a lateral external one, which corresponds with the jjrominent lateral edge of the V. A. little confluence of these elements will give the type of Lambdotherium. Were the median external marginal cusps wanting, the superior molars would be much like those of Hyracotherium, with less tendency to confluence of the median cusps than in most of the species of that genus. The supe- rior molars are also much like those of Acoessvs, but the premolars are different. ' But one species is known to me — ECTOCION OSBORNIANUM Cope. Oligoiomua osbomianug Cope, Paleontological Bulletin No. 34, 1881, December 20, p. 182. Plate XXVe; figs. ^10. The true molars of both maxillary bones, with the fourth premolar of one side, are preserved more or less perfectly, with four inferior molars on two fragments of the lower jaw. The external tubercles of the superior molars are nearly erect, and have a lenticular section. The rib which separates their external faces is prominent, and terminates in a free apex. The base of each face is marked by a strong cingulum, but the posterior one is very short. There is a strong anterior basal cingulum, but no posterior or internal one. The ante- rior inner tubercle is larger than the posterior. The intermediate tubercles are subround, and are anterior to the transverse line of the interior ones. They do not join the latter, excepting after very considerable wear. The external anterior cingular cusp is rather more prominent on the first than on the second true molar. The fourth superior premolar has a well-marked external anterior cingular cusp, which is, however, low; and there is no PALiEOSYOPS. 697 ridge dividing the external faces of the external cusps. The single inner cusp is connected with the two external by two ridges, which diverge as they extend outwards. The anterior supports a tubercle close within the anterior external. There are strong anterior and posterior basal cingula and weak external and internal ones. The third inferior premolar has a compressed ridge on the heel. The fourth premolar is like a true molar, with the anterior inner cusp well devel- oped and elevated, and connected with the anterior and posterior external by oblique ridges. The inner postei'ior cusp is less conic in form than in the true molars, and the entire crown is somewhat contracted anteriorly. Tlie true molars are characterized by the presence of a small median tubercle on the posterior border. There is a low external basal cingulum, which is wanting opposite the posterior cusp. Enamel generally smooth. In my original description I stated that there is a diastema in front of the second inferior premolar. This is an error based on a deceptive appear- ance of the jaw. Measurements. Length of superior true molar series 0210 Diameters of superior M. a J ^"^'"■''P°«*«"°' ^^^ i transverse iM)97 Diameters of Pm.iv J ''''t«r°P°«t*'"°'' "^^^ i transverse 0085 Length from inferior Pm. iii to M. ii, inclusive 0290 Diameters of Pm.iv^*°'*^^P°«t«"'"^ — •"°^<' transverse 0050 _. . i. • J. • HI ..(anteroposterior 0075 Diameters of infenor M. ii ^ '^ C transverse 0060 Depth of ramiis between Pm. iii and Pra. iv 0150 This species was, to judge from the size of its teeth, about the size of a red fox. The specimens of it above described were found by Mr. J. L. Wortman in the bad lands of the Big-Horn River, Wyoming. It is dedi- cated to my friend, Henry L. Osborne, of Princeton College, New Jersey. PAL^OSYOPS Leidy. Haydeu's Geological Survey of Montana, 1871, p. 358 (?). Proceedings Academy Natural Sciences, Phila- delphia, 1871, p. 118. Report of the U. S. Geol. Survey of the Territories, I, p. 27, Cope. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 591. Limnohijus Manh, American Jour- nal Science and Arts, 1872, p. 124. This genus has been partially described by Professor Leidy, and much light is thrown on its structure by the materials obtained by the Princetrin 698 THE BRIDGER FAUNA. Scientifin Expedition of 1877. As pointed out by Leidy, this genus differs from Palceotherium in the isolation of the internal cones of the superior molars from the external longitudinal crescentoid crests, and in the presence of but one inner tubercle on the last three premolars instead of two. There is but one internal cone on the last superior molar. Formula, I. 3, C. 1, Pm. 4, M. 3. Number of inferior molars similar. Inferior true molars, with four acute tubercles alternating in pairs and connected by oblique crests, which thus form two Vs, with their apices exterior. The last molar adds a fifth posterior tubercle. The last premolar lacks the posterior inner tubercle. The second and third have but one, the outer series of tubercles, and the first is compressed. The canines are separated by a slight interval from the premolars, and are in the continuity .with the incisors. The premaxil- lary bones do not reach posteriorly as far as the nasals. The molar characters are generally similar to those of Menodus, but the latter has two internal tubercles of the superior premolars, and only three inferior premolars. The species originally named by Leidy Palceosyops pahidosus belongs, according to Marsh, to the succeeding genus, Limnohjiis Leidy. When first described, it was not characterized generically, a brief specific description only being given. He afterward included species of Palceosyops in it, and in so doing first characterized the genus. Hence I agree with him in retain- ing the name Palceosyops for the latter, and not the former, as is done by Marsh. My material does not permit me to give a description of all the generic characters, since portions of skeletons in my possession cannot be referred to their species with absolute certainty. Neither Dr. Leidy nor the Prince- ton paleontologists have baen more fortunate, judging from their writings. These authors have, however, described various bones which they believe to pertain to the genus. Neither of them gives the number of the digits, which were probably four in front and three behind. I extract the following observations from the Report of the Princeton Scientific Expedition for 1877. "In general features it {Palceosyops major) strongly resembled the tapir, with stout body, slender tail, and very short neck, compensated by a pro- boscis of considerable length. In comparing the heads of the ancient and PALiEOSYOPS. 699 modern representatives of this class of Perissodactyles the points of con- trast are the wide, stout zygomas, the deep temporal fossae, the protruding nasals, and the narrow gaps in the dental series of the older type. "There are also strong points of resemblance in the structure of the Palceosyops and the Palseothere. * * * The pelvis and particularly the ilium and acetabulum of Palceosyops are more palseotheroid than tapiroid. The similarity in the fore-shoulder in the two types is striking. * * * In the descending series of Palseotheres, terminating in the diminutive P. minus and characteristic of the upper Eocene of France, we have an inter- esting counterpart in the large [genus] of Palceosyops, of equal diversity of size." I have obtained jaws and other parts of four different species of this genus, which may be distinguished as follows: * Superior i>remolars with complete internal basal cingula. Length of superior molar series M. .220; external cusps of superior premolars little separated ; enamel smooth P. vallidens. * * Internal cingula of premolars incomplete or wanting. Length of superior molars M. .175; external cusps of premolars well separated; en- amel wrinkled P. major. Length of superior molars M. .150; cusps of j)remolars separated; enamel smooth. P. Icevidens. Length of superior molar series M. .100; cusps of premolars separated; enamel more or less wrinkled P. borealis. The genus ranges from the lower to the upper Eocene. It has not been found in the typical Wasatch beds of Wyoming and New Mexico, but the P. borealis comes from the overlying horizon, the Wind River. The P. major belongs to the Bridger, and the P. Icevidens to the Bridger and allied Washakie. The P. vallidens has as yet only been found in the Wash- akie. Two other species have been proposed by Leidy on specimens from the Bridger, both of small size. These are the P. humilis and P. junior. PAL.E0SY0PS VALLIDENS Cope. Palseontological Bulletin, No. 7, p. 1 (August 22, 1872). Proceeds. Amer. Philo. Soc, 1872, p. 48". Annual Report U. S. Geol. Survey Terrs., F. V. Haytlen, 1872 (1873), p. 591. Plates LI, fig. 1; LII, fig. 3; LIU, fig. 1. Represented by the dentition of one maxillary bone with other bones of one individual; a portion of the same dentition of a second; with both 700 THE BRIDGER FAUNA. rami of the mandible, with complete dentition, of a third. The species is distinguished by the details of the dental structure, and by the superior size. It exceeds, in this respect, the Palceosyops major Leidy; in which the three posterior lower molars measure M. .108 in length, while the same teeth of the present animal measure M. .145. The last superior molar of another specimen measures M. .051 in length; in a third, the first true molar is M. .038 in length, while the last inferior molar is .057 inches long. The peculiarity in the structure of the superior premolars consists in the existence of two strong transverse ridges, which connect the inner tubercle with the outer crescents, inclosing a pit between them. In the premolars is also found the peculiarity of the almost entire fusion of the outer cres- cents into a single ridge. These united crescents are narrower than in P. major, and the summits of all the crescents are relatively more elevated. The external vertical ridge is weaker than in the other species of the genus. The number of inner tubercles is the same as in that species; all the teeth have very strong basal cingula, which extends on the inner side on the pre- molars only. The inferior molars are relatively narrower than in P. major, and the posterior tubercle of the last is larger and longer, and is an elevated cone. The inner tubercles in all the lower molars have broader bases and less acumination than in that species. The bones containing the maxillary and mandibular teeth were not found together in any instance, so that it is possible that the different series may represent different species. No other species of the genus was, how- ever, found in the localities to which the respective parts could be referred. Should these prove not to pertain together, the lower jaws may be regarded as typical of the species. The mandibular rami are less robust than in P. major, and are rather thin posteriorly. The dentary portion is compressed, and presents a longi- tudinal concavity on the inner side above the inferior border. There is a large mental foramen below the second premolar. The first premolar is one-rooted. The second has no antei'ior basal tubercle, and supports a principal cusp and a heel, which has an oblique median ridge. The fourth premolar has the two Vs, but the anterior ridge of the anterior one and the posterior ridge of the posterior one ai-e weak. The true molars increase PALiEOSYOPS. 701 rapidly in size posteriorly. In the last molar the ridge connecting the posterior lobe with the median is low, only giving a connecting dentinal band after considerable wear. The inferior canine is not very robust. Measurements. M. Length of complete ramus from anterior base of Pm. iv 0.295 Length of do. posterior to M. iii 143 Depth of ramus at Pm. ii 051 Depth of ramus at M. iii anteriorly 07'2 Diameter of inferior canine at base of crown 018 I found the specimens above described in the Mammoth Buttes, South- western Wyoming, near the headwaters of Bitter Creek. The formation is the Washakie basin of the Bridger. Since my examination of this locality the Princeton Exploring party obtained specimens of this species in the same region. PALiEOSYOPS MAJOR Lcidy. Survey of Wyoming, 1871, p. 359. Report U. S. Geol. .Survey Terrs., 1873, 1, p. 45. Report of the Prince- ton Scientitic Expedition, 1878, p. 27. Limnohyus robustus, Marsh, Anier. Jour. Science and Arts, 1872, p. 124. Plate LI, fig. 2; LII, figs. 1, 2. I found remains of this species not uncommon in the Bridger region^ especially on Cottonwood Creek, Black's Fork of Green River, etc. I can- not add anything to the descriptions above cited. Pal.s;osyops L.a;viDENS Cope. Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 591, and Report U. S. Geol. Snrv. Terrs., I, 1873, p. 30; not loc. cit., j). 28, nor Limnohyvs Iceeidens, Cope; Proceed. Amer. Philos. Soc, 1873, pub- lished January 31. Falwosyops paludosus, Leidy; Hayden's Survey of Montana, 1871, p. 359; Proceed. Acad. Nat. Sci., Philada., 1870, p. 113. Plate L, figs. 1-3. This species is smaller than the P. major, but Dr. Leidy was not satisfied that it is entitled to distinct specific rank on this account. In my report to Dr. Hayden in 1872, I distinguished it from the P. major by the simply lobate form of the external wall of the second superior premolar. In P. major this tooth has two external lobes as in the succeeding premolars, the posterior lobe being smaller than the anterior. This character of the P. IcBvidens is displayed in Dr. Leidy's figures. 702 THE BRIDGEE FAUNA. I have various specimens referable to a species of the size of this one, but the only one which displays the entire superior dental series is a part of a skull from the bad lands of Cottonwood Creek, Wyoming (Plate L, figs. 1, 2). It agrees in its measurements with some of the specimens de- scribed by Dr. Leidy under the name of Paloeosyops paludosus. A second specimen (Plate L, fig. 3), from the Washakie Basin, is intermediate in dimensions between the latter and the P. major. I have not seen the second superior premolai-. On this account, and on account of its dimen- sions, I cannot be • sure of its specific position, but describe it under the present head. Should the skull above mentioned prove to belong to the P. paludosus Leidy, and the other specimen belong to another species, the latter may bear the name under which it has been and is now described. In the cranium the prominent features are the elongate nasal bones, and the deeply excavated external nares. The former are well preserved, they are of equal width throughout, and have a flat superior surface and strongly decurved nareal bordei's. Their distal exti'emities are subtrun- cate, each bone slightly rounded. The nareal border is above the anterior part of the second premolar. The posterior ascending branch of the pre- maxillary bone disappears from the nareal border above the middle of the canine tooth, or .030 M. anterior to the posterior nareal border. The face between the nares and orbit is flat; below its middle the large infraorbital foramen interrupts the surface. The surface at the canine alveolus is very prominent, standing out much beyond the surface at the premolar teeth. The malar ridge projects immediately from the border of the infraorbital foramen. It is very prominent below the orbit, presenting a horizontal surface downwards. Its external surface slopes obliquely inwards to the border of the orbit. The anterior border of the latter is over the postei'ior third of the first true molar. The malar bone presents a postorbital angle upwards. It is much expanded downwards posteriorly, and gives the in- ferior border of the zygoma a decurved outline. The superior border of the squamosal process rises strongly posteriorly. The premaxillary bones are not prominent, and their anterior extremities are transverse and not coossi- fied. The infraorbital foramen issues above the posterior part of the fourth premolar. The molars have the general form of those of P. major, but the PAL^OSYOPS, 703 second superior premolar has but one outer tubercle. The cingula are much less developed than in that species, those between the inner cones of the molars being entirely absent. These cones are low, and, with the rest of the crowns of all the teeth, covered with smooth and shining enamel. The anterior median small tubercle of the first true molar is wanting. The last true molar has but one interior cone. The canine tooth is powerful and bear-like, and has a rather short crown. It is wide in front, and has a cutting ridge posteriorly. The crowns of the incisors have prominent but not cingular bases. Measurements. M. Length molar series 0.140 Length true molars 085 Length three incisors 034 Length crown canine 030 Length crown last molar 039 Width crown last molar 036 Length cranium to lateral occipital crest 345 The teeth of the Washakie specimen are very smooth, but the basal cingula of the premolars are stronger than in the specimen above described. Measurements of No. 2. M. Length true molars (No. 2) 0.101 Length last molars (No. 2) (oblique) 039 Width last molars (No. 2) transverse) 038 This species was about the size of the Anoplotherium commune, Cuv., and intermediate between the Palceotherium magnum and P. medium. It is considerably larger than the existing tapirs, and was one of the most abundant of the quadrupeds of the Eocene of North America. Pal^siosyops borealis Cope. American Naturalist, 1880, p. 746. Bulletin U. S. Geological Survey Terrs., 1881, vol. vi, p. 196. Plate LVIII a, fig. 3. At present the only parts of the skeleton of this species which are known are the following : Part of the right maxillary bone, with four molar teeth; distal portions of both radii ; a lunar bone, and a basal median phalange. These fragments indicate a species much smaller than P. Icevidens and about equal to the Limnohyiis fontinalis. The true molars increase rapidly in size posteriorly. The external Vs 704 THE BKIDGEK FAUNA, are strongly inflected, and have a low median rib. Each internal cusp sends a low ridge outwards and forwards, and the anterior intermediate tubercle is distinct. The crowns have strong anterior and posterior cingula, but no internal cingula. The ledge that connects the inner cusps in P. major is represented by a tubercle in this species. The posterior cingulum of the last molar rises to a prominent ridge on the inner posterior margin of the crown. In a third premolar the anterior and posterior cingula do not connect on the inner side of the crown. The external cusps have a nearly vertical external wall, and are well distinguished ; the anterior one only has a median rib. It has no external cingulum. There is a weak one on the true molars. The enamel is smooth where worn ; on unworn surfaces it is somewhat wrinkled. Measurements of teeth. Length of true molar series 0.063 Diameters of first true molar 5 ^"t^^P^^^"™"" °1^ transverse 020 c anteroposterior 013 Diameters of third premolar I ^^^^^^^^^ p^g The shaft of the radius is not very stout, and shows a groove for con- tact with the ulna below. The carpal articular face is wide and depressed, and without trace of scapholunar ridge. A small part of both surfaces is recurved inferiorly, and each part is followed by a shallow fossa: these are separated by a low tuberosity. The cviboid has a rather short posterior extension, whose superior surface makes with the transverse anterior surface an L of branches of equal length. Below, the magnum and unciform facets are strongly concave, the latter a little the larger. No posterior tuberosity. The proximal phalange is longer than wide, and stout and flat. Measurements. M. Width of carpal facet of radius -j.. 0.03O Diameter (transverse) of radius at middle 018 I vertical 020 Diameters of os lunare 1 transverse above 017 ' anteroposterior 020 longitudinal 023 transverse 017 Diameters of phalange } The above fragments were cut from a single small block of matrix. The P. junior, according to Leidy, differs in the character of its supe- LIMNOHYUS. 705 rior molar teeth from the present species. That animal appears to lack the intermediate tubercles and crest, and has a much stronger external cingulum. The P. horealis has been only found thus far in the Wind River Eocene by Mr. J. L. Wortman. LIMNOHYUS Leidy. Proceedings Academy Natural Sciences, Philadelphia, 1872, p. 242 ; Cope. Annual Report U. S. Geol. Survey Terrs., 1872 (1873), p. 593. Palceosyops, Marsh, Amer Joum. Sci. Arts, 1872, p. 122, not of Leidy, 1871. This genus only differs from the last in possessing two conic tubercles of the inner series on the last superior molar, instead of one, a character first pointed out by Marsh. It is yet uncertain to what genus the species originally described by Leidy as Palceosyops paludosus belongs. The type specimens do not include the last superior molar, according to Leidy. The only superior true molar preserved possesses two internal cusps, and is, according to its describer, the second of the series. Professor Marsh, in arranging the species of the two genera, came to the conclusion that the last superior molar of the P. paludosus possessed two internal cones, which character he adopted as distinctive of the genus Pakeosyops. To the species with one inner lobe, he gave the name of Lininohyus. Subsequent to the original description of the P. paludasus, Leidy referred to it various specimens with only one internal cone of the last superior molar, and at that time defined the genus Paloeosyops as distinguished by that character. Thus Professors Marsh and Leidy were at issue as to which of the genera should receive the name Palceosyops. The decision of the question will depend on the rule adopted as to the conditions necessary to be observed in the proposal of new generic names. Those authors who deem it sufficient to establish a generic name, that it be merely printed, will follow the course adopted by Professor Marsh. In describing the original P(dceosyops paludosus Dr. Leidy did not characterize the genus Paloeosyops. This is a custom more to be honored in the breach than the observance, and one contrary to the rules of nomenclature. For the present writer the name Palceosyops did not at that time obtain a posi- tion in nomenclature. This was fully acquired at a later date, when Dr. 45 o 706 THE BELDGEE FAUNA. Leidy described both genus and species. The species then described was, however, diflPerent, according to Marsh's view, from the original P.jyaludosus. By this accident, the second species had a generic and an eiToneous specific name; and the earlier described species had a specific and no generic name. Dr. Leidy supplied the latter deficiency in subsequently naming the genus with two cones Limnohpus, a name already used by Marsh, and synony- mous with Palososyops. To those who will not again use a name which has become a synonyme this course would not appear judicious; for my own part, I never saw any disadvantage to arise from such a course. As to the second species, the Palceosyops without name, I called it Icevidens, thinking it very inconvenient to have two ])aludosi in two so nearly allied genera. Besides the L. paludosus, there are two large species of Limnohpus, L. laticeps Marsh, and L. diaconus Cope. The L. fontinalis Cope is a smaller form. LiMNOHYUS DIACONUS Cope. Anunal Report U. S. Geological Survey Terrs., 1872 (1873), p. 593. Paloeoayopa diaconus Cope, PaliBon- tological Bulletin, No. 12, p. 4, March 8, 1873. Plate LI, fig. 3. This large species is represented by parts of the two maxillary bones, which present the crowns of the third and fourth premolars, and of the sec- ond and third true molars, with the bases of the other molars and premo- lars. The third true molar is injured posteriorly, but enough remains to show that it possessed two internal cones. The jaw is as large as the PalcBOsyops major of Leidy, but difiers in the relative proportions of the teeth. Thus the last three molars have the same anteroposterior length, while the space occupied by the four premolars is shorter. The anterior and posterior cingula of the true molars are very strong, but it is not well marked on the inner side, between the cones. The latter are acutely conic, and the median anterior tubercle is strongly devel- oped. Although the wearing of the teeth indicates maturity, the enamel is coarsely and obtusely rugose. The fourth premolar differs from that of the four species of Palceosyops described, in its smaller size relatively and abso- lutely, and in the presence of a prominent vertical tubercle on the outer iace, rising to the angle of the deep notch between the lobes. It has a com- LIMNOHTUS. 707 plete interior basal cingulum. The third premolar is as wide as the fourth, and about as large as the corresponding tooth in P. major, but different from it in the absence of tubercle and ridge that mark its external face. The first premolar has two roots, and the canine is large and stout. Measurements. u. Length of entire molar series 0. 1740 Length of true molars 1060 Length of last molar (crown) 0420 Width of last molar (crown).. 0473 Length second molar 0350 Length fourth premolar 0260 Width fourth premolar 0260 Width third premolar 0200 Length third premolar 0200 Diameter of basis of canine 0263 The L. j)ahidosus Leidy is similar to this species in the rugosity oi the enamel of its teeth, but appears by the measurements to be distinctly smaller. My expedition did not obtain any specimens which I can as yet certainly refer to this species. The measurements given by Professor Marsh for his PaloEOsyops {Lymnohyiis) laticeps approaches very nearly to this one Thus the width of the crown of the penultimate superior molar in L. palu- dosus is M. .C38; in L. laticeps, .036; in L. diaconus Cope it is .042. In comparison with Marsh's description of his P. laticeps, the measure- ments are all larger, and the enamel is as rugose as in L. major, instead of smooth. The shortening of the premolar series is the same in the two spe- cies; thus, in P. laticeps the two sets of molars are related as 94°"° to 61; in the present one, as 106: 68. From Henry's Fork of Green River. LlMNOHYUS FONTINALIS Cope. Palocosjjops foniinaUs Cope, Pal.'eontological Bulletin, No. 11, p. 1, Jan. 31, 1873. Proceedings American Philosophical Society, 1873, p. 35. Limnohyus fontinaUs Cope, Annual Report U. S. Geol. Survey of the Territories, 1872 ri873), p. 594. Plate XLIX, fig. 9; Plate L, fig. 4; and Plate LVUIa, figs. 4-6. This chalicotheroid is represented in my collection by a considerable part of the skull of one individual. This includes the greater part of the occipital and parietal bones, with the right squamosal almost entire; the right maxillary and malar as far forwards as the fourth premolar tooth ; and 708 THE BRIDGER FAUNA. the nasal and attached part of the right maxillary bones. The portions belong to a species of about the size of the Palceosyops horealis, and smaller tlian any of the other species of the two genera here described. The nasal bones in profile have a horizontal superior surface. They are very convex in transverse section, and their extremities are emarginate. The infraorbital part of the malar is regularly convex, and overhangs the maxillary bone extensively. Its postorbital limit is marked by an angle directed at 45° inwards. The z3'gomatic part of the malar is flat externally. The squamosar portion of the zygoma is not much elevated. The temporal fossa is rather wide posteriorly, and the inferior temporal ridge is extended horizontally. The postglenoid process is rather narrow and elongate. The posttympanic process is robust, and is well separated from the postglenoid, leaving an especially wide meattis auditorius. The front is flat, and the supe- rior temporal ridges converge gradually to an isthmus, but scarcely form a sagittal crest. The isthmus expands to the nan-ow lateral occipital crests. The occipital bone sends a long process forwards on the median line,- forming a half-gomphosial articulation with the parietals. The lateral suture of the two bones is considerably in advance of the posterior lateral crest. The maxillomalar suture is on the convex infraorbital ridge. There is a postparietal foramen; also a small one in the sqiiamosal bone posterior to the position of the supraglenoid. There is above this a postsquamosal on the parietal suture. The second true molar is abruptly larger than the first. In none of the true molars are there ridges extending outwards from either of the- internal cusjds, nor is there any posterior median tubercle. The anterior median tubercle is distinct. Thei'C are no external nor internal basal cingula, but the anterior and posterior are distinct. The latter, however, only connects the two cusps of the posterior side of the crown. The outer sides of the Vs have a trace of a median rib. The enamel is nearl}^ smooth when worn, but finely rugose before protrusion. M. Length of true molar series ("2.75 inches) 0.067 Leugth of last mol.^r 025 Width of last molar 0J6 Length of penultimate molar 0-26 Wi«ith of penultimate molar 026 Depth squamosal process 025- LAMBDOTHEEIUM. 709 Found by the writer on a bluff on Green River, near the mouth of the Big Sandy Creek, Wyomino-. LAMBDOTHERIUM Cope. AiDerieaii Naturalist, 1880, p. 74S, September 20. Bulletiu U. S. Geological Survey Terrs., VI, 1S81, p. 19(>. (?) Helolheriiim Cope, Pal;eoutolngical Bulletin No. 2, p. 1, August 3, 1-72. Proceediugs Araericau Phiiosopb. Society, 1872, p. 4lJti. (Xoinen jiHdiim.) This genus is as yet only known to me from teetli of both jaws and from mandibular rami. The dentition is much as in Limiiohjiis, excepting that there is a diastema in front of the second inferior premolar. Presence of first inferior premolar not ascertained. Fourth inferior premolar with- out posterior cusps. Superior molars with an angular ridge extending inwards from each inner cusp. Last inferior molar with heel or fifth lobe. The inferior molars in this genus are quite as in the other genera of this family, while the superior molars show a tendency to Anchitliermm in the well-defined tubercle and low crest extending outwards and forwards from the internal tubercles. The external Vs are separated b}* a strong rib. The internal cusp of the superior premolars is simple, and the external cusps are well distinguished. If the ridges, which are rudimental in the molars of Hi/racotherium, should be developed, and the external cusps of the superior molars be flat- tened externally, the result would be the dentition of Lamhdotherium. I am acquainted with three species of Lamhdothermm, which differ materially in size. The larger two are from the Wind River Eocene; the smallest is from the Brido-er. ^b^ Lambdotherium brownianum Cope. BiUletin U. S. Geological Survey Terrs., VI, 1S81, p. 196. PlatoLVIa; fig. 10. Considerably larger than the L. popoariicum, and about equal to the Tajnrus terrestris. The greater part of a lower jaw represents the species, and on this unfoi*tunately only one of the premolar teeth remains. The three premolars are all two-rooted, and the posterior lobe of the last true molar is well developed. The inferior part of the external side of the ramus contracts or retreats rather abruptly posteriorly below the last molar. It presents a slight external convexity below the second and third premolars. 710 THE BRIDGER FADTSTA. The alveolar line rises rapidly posteriorly, so that the last true molar is quite oblique. The second (first) premolar has a considerable heel, which is narrow and elevated on the middle line. The principal cusp is large and compressed, but obtuse, and has no anterior basal tubercle. Meamirements. if. Length of six mol.irs 0.090 Length of true molars 055 / vertical 009 Diameters second (first) premolars anteroposterior 012 ' transverse 006 Length of base of first true molar 015 Width of base of first true molar 009 Length of base of third true molar 0i3 Width of base of third true molar - Oil Depth of ramus at second premolar 030 T-, ., ^ . ,r .••< at front of tooth 039 Depth of ramus at M. HI < , „ , ' < at end of tooth 047 Dedicated to my friend Arthur E. Brown, superintendent of the Phila- delphia Zoological Garden. Lambdotherium popoagicdm Cope. American Naturalist, IRtfO^ p. 748. Bulletin U. S. Geological Survey Terrs., VI, 1881, p. 196. Plate XXTX «, fig. 7, and Plate LVIII, figs. 3-5. This is the most abundant Perissodactyle of the Wind River beds, remains of at least twenty-two individuals having come under my observa- tion. The general characters of the inferior molars are as follows: The heels of the second and third inferior premolars have a median keel ; the third only has an anterior tubercle. The crest of the heel of the fourth forms an imperfect V. Heel of the last true molar small. No cingula. Enamel smooth. Length of series, .080; of true molars, .044; of last molar, .019; depth of ramus at first premolar, .021 ; at last molar, .031. The crowns of the superior molars are very short; their external Vs are well distinguished by an intermediate vertical protuberance, but their external faces are less obliquely sloped inwards than in the species of the genera Lhnnohjus and Palceosyops. Traces of the median ribs on the exter- nal faces of the Vs are slight. The tuberosity which bounds the anterior V ill front is very large, and its apex is continued into the anterior basal cingulum, as in Lopldodon and allies. Its size causes the external wall of LAMBDOTHERIUM. 711 the molar to be oblique to the other sides of the ci'own. The anterior and posterior cingula of the molai's are very strong, but they do not extend quite round the inner bases of the internal cusps. The latter are rather acute, and their opposed faces are flat and meet at an angle. The interme- diate tubercle is large, has a subacute summit and a triangular base. The ridge which passes forwards and inwards from the posterior internal tuber- cle does not reach the external lobe, and rapidly diminishes in elevation. There is no well-defined external basal cingulum. In the superior pre- molars the external cusps are separated by a notch, and have no external ridge between them. Each has a feeble median rib. There are posterior and anterior cingula, of which the latter terminates externally in a low tubercle. There is a low external cingulum, but no complete internal one. The superior premolars have an anterior intermediate tubercle. Measurements of separated suj^erior molars. Diameters Pm.ii^'^°*«'^"^P°«t«"'"' O-*'"^ ( transverse 010 Diameters Pm.iii I ''»*«™P''^*"'°^ «°^ ( transverse 112 Diameters Pm.iv I •■'"'""I'«^"^'''°'^ ^^^ ( transverse 012 Diameters of true molar ^'^°t"0P''^t'=""'- "^^^ < transverse 0160 Elevation of crown 007 The ramus of the lower jaw is compressed and quite deep. The coro- noid process rises abruptly from the alveolar border, and the masseteric fossa is little marked. There are two mental foramina, which are below the second and third premolar teeth, respectively. The posterior extremity of the symphysis is opposite the anterior root of the second premolar. This posterior position leads me to suspect that the first premolar may be wanting. This tapiroid was about the size of the Ilijrachyics agrestis,hutless robust. Wind River Eocene of Wyoming. Found by Jacob L. Wortman, Lambdotherium procyoninum Cope. Melotheriitm procyoninum Cope, Palseontological Bulletin No. 2, p. 1, August 3, 1872. Proceedings American Philosophical Society, 1872, p. 466. Annual Report U. S. Geol. Survey Terrs., 1872 (1873), p. 606. Plate XXIV; fig. 22. As this species is only known from a superior true molar, its generic 712 THE BEIDGEE FAUNA. position is not certainly known. The tootli in question is very much like that of the Lambdotherium popoagicum, but differs in easily recognizable specific characters. The crest that extends from the posterior inner tubercle reaches to a point between the external lobes, and is therefore longer than in the species named. It also shows a slight tendency to a division cutting off an intermediate tubercle, like the anterior one. The median ribs of the external Vs are more distinct than in L. popoagicum. The anterior and pos- terior cingula are distinct, and the external and internal are neai-ly complete. The crown is low, and the enamel nearly smooth. Meaxurements. M. I auteroijosterior 0.0070 Diameters of crovrn •? vertical - 0035 ' transverse 0090 The molar tooth is about the size of that of a raccoon; hence the name. Cottonwood Creek, Wyoming. Bridger Epoch. MACRAUCHENIID^. But one genus of this family is knoAvn at the present time. The fol- 3 1 lowing are the dental characters of Macrauchenia; formula: I. -; C. -; Pm. O J. 4 3 - ; M. - ; forming an uninteiTupted series. The superior molars present two external Ys and two oblique trans- verse crests, somewhat as in Palceotherium. The spinous foramina pierce the neural arches of the dorsal vertebra (Gervais). There is no intertrochlear crest of the humerus, but the carpal facets of the radius are well distin- guished. The internal malleolus is small, but the fibular malleolus is coos- sified with the tibia at an early age, and articulates with the calcaneum. The trochlea of the astragalus is well developed. The lateral digits are large, and the distal keels of the metapodials are continued on the anterior faces of the condyles. The position indicated by the above characters is a remarkable one. The uninterrupted dental series and the absence of interti'ochlear humeral crest are primitive features among ungulate Mammalia. The radio-carpal PEEISSODACTYLA. 713 articulation is faceted as in the hiorher ung-ulates, but lacks the inferior condyloid face of those types. The completeness of the metapodial distal keels is a feature of high special organization only seen in the Equida; of this order The coossification of the external malleolus is also a character peculiar to the Equidoa among the Perissodadijla. There are two other char- acters which are not elsewhere found in this order, viz, tlie articulation of the fibula with the calcaneum, and the absence of the vertebrarterial canal. Tlie former belongs to the Artiodadyla generally, and to the Prohoscidea, and the latter to the ruminant family of the Camelida. Tims the Macrau- cheniidce stand out as one of the most distinct of the families of the Perisso- dadi/ht, and one to which we may anticipate considerable accessions in future. But two species of Ilacrcmchenur are known, a larger 31. pcda- clionica, and a smaller, 31. hoUviensis, both from the Pliocene formation of South America. MENODONTID^. The known genera of this family are not numerous. They are defined as follows: a. Last supei'ior premolar ouly with two inner tubercles. Incisors present DipJacoclon. aa. All the superior i^remolars with two interior cusps. Six inferior incisors ; canines very large Dceodon. Six inferior incisors ; canines very small . - Menodus. No inferior, and four small superior incisors ; canines very small Symborodoti. The genera are, as yet, exclusively American. Diplacodon, in its sim- pler premolars, approaches the Chalicotheriidce, and is the oldest of the American genera. It is from the Uinta or Upper Eocene. 3Ienodns and Sijmhorodon, which include some species of gigantic size, belong in the White River or Oligocene, Avhile Dceodon has so far only been obtained from the John Day or Middle Miocene. Up to the present time no species of this family have been described from the American Middle Eocene PAL^OTHERIID^. This family has been already defined. In its complex premolar teeth, which in the upper jaw resemble the molars in composition, it shows an 714 THE EOGENE FAUNA. advance over the Chalicotheroid and other genera of the Lower Eocene. In fact, it has not been found in the Lower Eocene, but commences in the Upper Eocene in the genera Palceotherium and Paloplotherium. Thence it extends to the very summit of the Miocene, and may even occur in the PHocene {Hippotherium i^^'o^ohippus). Its members exhibit considerable range of variation in the details of the teeth and feet, but no striking break of family imjiortance occure. The most noteworthy interruption is that which is found between the Palocotherince and Hippotheriince, where there is a change in the form of the proximal extremity of the humerus from a tapiroid to a horse-like form, and a modification of similar significance in the molar teeth, by the addition of a deposit of cementum. The characters of the genera are as follows: I. Palwotheriince. Bicipital groove of bum ei us simple; teeth Tvitliout cementum. «. Oue or more internal tubercles of sHi)erior molars distinct. External Ys of superior molars not well distinguished externally Anchilophus. External Ys separated by a vertical rib; intermediate tubercles not connecting fore and aft Paloplotherium. External Ys separated; intermediate tubercles extended fore and aft Anchipims. ««. Internal tubercles of superior true molars continuous with the transverse ridges. Inferior molars with two Ys only ; lateral toes large Palceotherium. Inferior molars with cusps at the inner extremities of the Ys ; lateral toes small. Anchitherium. II. Hippotlieriinw. Bicipital groove of humerus double; molars with cement in the valleys. (Intermediate tubercles connected fore and aft.) a. One or more internal tubercles of superior molars distinct. Inner lobes of inferior molars enlarged Mippotherium. aa. Internal tubercles of molars not distinct. Inner lobes of inferior molars enlarged Protohippus. The genera of this family are generally of less antiquity than those of the Chalicotheriidce, and they range from the Middle Eocene to the Pliocene. Paloplotherium is found in the Middle Eocene, and is, as might have been anticipated, more nearly allied to the Chalicotheriidce than any other genus of this family. Pachynolophus also is not far removed from it. Anchilophus is Upper Eocene, and is allied to the genus just named, which connects both genera with the Lophiodontidoc. These early genera constitute by their similarity the bond of connection between the three families, which in their PERISSODACTYLA. 715 later and specialized forms are very diflferent from each otlier. Palceothe- rium is chiefly found in the Upper Eocene, and Anchitherium commences in America in the White River or Oligocene, an age between Eocene and Miocene. In Europe it commences in the Middle Miocene, and has An- chippus for a cotemporary. Hippotlierium existed only in the latter part of the Miocene epoch, consistent!}' with the greatly specialized structure of its limbs and teeth, and the nearly allied Protohippus lived with it, while in Europe a species with the same type of molar teeth is found in the Pliocene epoch (Forsyth-Major). These forms were cotemporary with the Equidoe, which outlived them. They have many points of resemblance to that family, but nevertheless remain at a considerable interval from them in the structure of the feet. The geographical distribution of these genera, so far as present knowl- edge shows, is as follows : North America alone — Auchippus. North America and Europe — AncJiifheritim , Hippotherium, Protohippus. Elurope only — Anchilophus, Paloplotlierium^ Pakeotherium. EQUID^. The two genera of this family are distinguished as follows : Interual lobes of superior molars subequal Hippidiutn. Anterior iuternal lobe of suiierior molars mucli larger than the posterior Equus. The genus Hippidium is extinct, and its species have been thus far only found in North and South America, in beds of Pliocene age. Equus made its appearance during the same period, and is represented by several exist- ing species. Besides the reduction in the number of digits, which is carried further here than in any other family of Mammalia, there are several other charac- teristics of specialization. Thus, in the dentition the spaces between the tubercles are filled with cementum. These valleys are generally deep, owing to the prismatic foi'ms of the molars. The cups of the incisors are completely developed, and also filled with cementum. There are two bicip- ital grooves of the humerus. The preceding characters are also found in the HlppjotheriiiKB of the Pakeotherikke. The Eqnidce adds another evidence of 71(5 THE EOCENE FAUNA. greater specialization than the latter group in the structure of its feet, i. e., the distal metapodal keels are completed forwards, as in most ruminants. The similarity of the modifications which have supervened on the Artiodadyle and Perissodacfi/lc lines, in attaining their most specialized extremes, has often been noticed. I repeat them here in tabular form in three columns.* These show (Table I) the modifications in which the Eqiddm and Bovidce are identical, or nearly so, which place them at the heads of their respective orders; Table II, those in which the Equidce are the more special- ized of the two; and Table III, those in which the Bovidce display the highest differentiation. *T.\BLE I. Table II. Table III. 1 Obliteration of first iiremolars. Cupping of incisor teeth. Absence of superior incisors. 2 Selenodout and prismatic character Deposit of cemcntum in teeth. Trough-shape of odontoid. of molars. Double bicipital groove of Greater involution of lumbar 3 Flattened odontoid jiroccs-s. humerus. prezygapophyses. 4 lutertroclilear crest of Immerus. Reduction of metapodials to Fibular articulation of calca- 5 Rednctionand coiissifieatioii of ulna. one. neum. C Distal facets of radius. Distal ginglymus of astraga- 7 Involution of lumbar prezygapo- pbyses. lus. 8 Elongate sacrum. 9 10 Shaft of fibula atrophied and its distal extremity coiissi tied to tibia. Reduction in mimber of digits. 11 Anterior extension of carinse of metapodial bones. ARTIODACTYLA. Members of this order were very few in number in the true Eocene periods, so far as our present knowledge extends. The great subdivision of the Ruminantia did not exist, the only types being the Suillines and the Eiirytheria. The characteristics of these groups will be more fully defined in Part Second of this work, which treats of the White River epoch, during which both of the divisions in question were numerously represented. OMNIVORA. Two, and perhaps three, genera of hogs from the Eocene beds of our Western regions have come under my notice. They differ from all existing members of the suborder in the anisognathous chai-acter of their molar AETIODACTYLA. 717 dentition ; that is, the superior molars have a greater transverse diameter than the inferior ones. In this they agree with alHed genera ah-eady found in Europe, as Choeropotamus Cuv., Anthracotherium Blv., and show a greater resemblance to the ruminant division than do the recent hogs. The last- named genus approximates Hyopotamtis, which is still nearer the lowest Ruminantia. PANTOLESTES Cope. Proceed. Anier. Pbilos. Soc, 1872, p. 467. (Separata, August 30.) Report U. S Geol. Surv. W. of 100th Mer., iv, p. 145. The type of this genus resembles in structural characters of the denti- tion of the lower jaw the Hyopsodus and Sarcolemur, already known in the collections of the different explorations of the Rocky Mountain lake basins. While it possesses the normal number of molar teeth belonging to these, it preserves a sectorial character of the premolars more posteriorly than in any of the genera named. The premolars are all two-rooted, except the first. The fourth is a simple flattened triangular cusp, with a small tubercle at the base behind, and wanting the inner cusp of other genera. The molars exhibit the usual four cusps, the external cresoentoid, the inner discoid in section, excepting the inner anterior, which is generally duplicated by an anterior twin-cusp of smaller size, closely united with it. Six species of this genus have been described from lower jaws only, and in one only, the M. hracJiijstomus, are both superior and inferior molars known In the P. secans the sectorial character of the fourth inferior pre- molar is most strongly marked; in P. lonrjicaudus that tooth has a wider heel than the other species. The species of Pantolestes may be distinguished as follows : a. Fourth premolar treucbaut everywhere, longer than second true molar. Leug'tli of true molars M. .0150 ; second molar \vith but one anterior inner cusp . P. secans. na. Fourth premolar with blunt heel, not longer than second true molar. Length of true molars .0230; no anterior cusps of premolars P. etsagicus. Length of true molars .0100; all with double cusps P. chacensis. Length of true molars .0140; fourth premolar with minute anterior cusp, and long heel , P. longicaudus. Length of true molars .0130; fourth premolar large, .005, with double anterior cusp, and short heel ; molars with double cusps P. metsiacm. 718 THE EOCENE FAUNA. Length of true molars .0138; fourth premolar short, .0045; anterior cusps of true molars single P. brachystomus. Length of true molars .0105; fourth premolar small, .0035; without anterior cusps and M-ith two ridges on heel ; true molars with double anterior inner cusps P. nuptus. I originally arranged this genus in the 3Ie$odonta, as only the dental characters were then known. These resemble also those of the suillines, where I once provisionally placed the genus Mioclcemis, which proved later to be a creodont. The possession of the bones of P. brachystomus shows that that species belongs to the Artioclactijla. A few bones, including metapodials, of the P. longicaudus, are preserved, but it is from remains of the P. brachystomus that the characters of the skeleton of this genus are derived. A lumbar vertebra of the M. brachystomus has flat articular surfaces. The ilium has a rather long j^eduncle, much wider than deep, with a ti-ian- gular section. The base of the triangle is rather short, and is concave. The acetubular cotyloid notch is open. Femur with prominent greater and lesser trochanters, but no third trochanter. Trochanteric fossa profound. Head with fossa ligamenti teris isolated from neck. The characters of the tarsus are typically those of the order Artiodactyla. The astragalus exhibits a distal trochlea which is continuous with the sus- tentacular facet, and which articulates with both cuboid and navicular. The distal portion of the fibula is free from the tibia, and its shaft becomes very slender. It is possible that a more perfect specimen would display it as continuous. Its distal extremity articulates with the ascending tuberosity of the calcaneum. The cuboid facet of the latter is narrow. The cuboid and navicular bones are distinct from each other and from the cuneiforms. The mesocuneiform is shorter than the ectocuneiform, and is coossified tvith it. There are probably four metatarsals. The median pair are distinct, but appressed ; their section together, subcircular. The lateral metatarsals are slender; the external one is wanting, but its facet on the cuboid bone is very small. These characters are in general similar to those of the genus Dichobune, but Cuvier does not state whether the cuneiforms are coossified in that genus or not. They are united in Anoplotherium. Pantalestes difi"ers from Bkhobune in the presence of but one internal tubercle of the superior ARTIODAGTTLA. 719 molars, and in the single external tubei'cle of the superior premolars. It is referable to a family to be distinguished from the AnoplofherUdce by the pres- ence of the external digits, and from that family, and from the Dichohunidce, by the possession of tritubercular superior molars. It will be called the JPantolestidce. The characters of the tarsus are of much interest, and demonstrate that Pantolestes is the oldest type of Artiodactyle 3-et discovered, and that it is not altogether primitive in some of its characters. Members of this order have been found by Cuvier in the Upper Eocene {DicJiohune, Anophtherium, etc.), but none have been determined as yet from the Suessonian of America. A species represented by teeth from the Siderolithic beds of Switzerland have been referred to Bicltobune (D. camjrichii Pict.) ; but dental characters alone are not sufficient to distinguish that genus from Phenacodontidce. Dr. Lemoine found astragali of a small Artiodactyle in the Suessonian of Reims, and has referred them to his supposed Suilline LopJdochcerus peroni. I have reported an astragalus from the Wind River formation of Wyoming Terri- tory, which is almost exactly similar to those found by Lemoine. The specimens of P. hrachjstomus enable me to characterize with some degree of completeness this interesting form, which precedes in time all the known American Artiodadyla. Pantolestes chacensis Cope. Systematic Catal. Vert. Eocene, New Mexico, 1875, p. 15. Report U. S. Geog. Surv. W. of lOOtli Mer., iv, ii, p. 146, pi. xlv, tig. 17. Plate XXIVd, fig. 5. The largest species, represented by four mandibular rami in the Big Horn collection. It has the fourth premolar more robust and less trenchant than in P. secans, and shorter than the last true molar. In P. secans it is longer than the last true molar. For fuller description, see reference cited. Pantolestes metsiacus Cope. Proceed. Amer. Philos. Soc, 1881, p. 149, Paleontological BuUetiu, No. 34, p. 149, Feb. 20, 1883. Plate XXIVd, fig. 6. A small species of the size of the P. hngicaudus, and distinguished by several peculiarities of dentition. The two cusps composing the anterior internal lobe of the molars are quite distinct, but appressed. Each one is connected with the external anterior lobe by a transverse crest, as is seen 720 THE EOCENE FAUNA. in Esthonyx, and these inclose between them a" fossa. This fossa is closed internally by the appression of the anterior inner cusps. The fourth pre- molar is not so large as in P. secans, but resembles in proportions that of P. chacensis. It differs from that of P. longicaudus in its very short heel and its large anterior basal tubercle. The latter is double, consisting of two small cusps, one within and anterior to the other. The posterior heel is distinct on both sides of the ridge that marks the median line. The posterior external lobe is V-shaped, and the posterior inner is a small cone. Between the two is a minute median tubercle. The posterior tubercles are not so elevated as in the species of Hyopsodus. A weak external cingulum ; enamel smooth. Measurements. M. Length Pm. iv, with M. i and ii (No. 1) 0140' Length Pm. iv 0048 Length M. ii 0048 Width M. ii 0040 Length M. iii (No. 2) ...*. OOCO Width M. iii 003* Depth ramus at Pm. iv (No. 1) OOGO Depth ramus at M. iii (No. 2) 0070' Portions of four mandibles preserved. No. 2 is a little smaller than No. 1, and No. 4 is a little larger than No. 1. From the Bis: Horn Basin. J. L. Wortman. Named from the name -given by the Crow Indians to the Big Horn River. Pantolestes nuptus Cope. Paleoutological Bulletin, No. 34, p. 150, Feb. 20, 1882. Proceed. Amer. Philos. Soc, 1681, p. 150. Plate XXIVd, fig. 7. This is the least species of the genus, and is represented by a portion of a right mandibular ramus which supports three molars, from the fourth to the sixth, inclusive. Besides its small size, this species is distinguished by the relatively small dimensions of the fourth premolar, which is shorter than the first true molar, instead of longer, as in all the other species. The well-developed basin of its heel, which is bounded by a ridge on each side, distinguishes it at once also from P. secans, and is more distinct than in P. chacensis. From the latter and P. metsiacus the entire absence of anterior ARTIODACTYLA. 721 basal lobes separates it. The well-developed pair of anterior inner tuber- cles shows that it cannot be an abnormal Hyopsodus vicariue, with which it agrees in size. The first anterior inner tubercle of the true molars is more widely separated from the second anterior than in any of the species of the genus, and is quite as in the species of Pelycodus. It is smaller than the second anterior inner, which equals in size the anterior outer. The heel is wide, inclosing a basin, which is bounded externally by an angular ridge. Its posterior inner angle supports a cusp, which is separated by a deep notch from the anterior inner cusp. External to it, on the posterior border of the crown, is a small tubercle. No basal cingula. Measurements. M. Length of true molars 0. 010 Diameters M. ii I ''°*"''P°^*"'°'" ^^ ( transverse 003 Depth of ramns at Pm. iv 007 Basin of the Big Horn. J. L. Wortman. Pantolestes brachystomus Cope. Proceeds. Amer. Philos. Soc, 1883, p. 547. Mioelwnus brachystomus Cope, Paleontological Bulletin No. 34, p. 187, February 20, 1882. Plate XXIII d, figs. 16-21. This small Artiodactyle is represented by the fragments of the skeleton of but one individual. These include the greater parts of the maxillary and mandibular bones, with the teeth; a lumbar vertebra; parts of both in- nominate bones, and of both femora, with the right tarsus with the attached portions of the tibia and metatarsus. The bones are about two-thirds the size of those of the Javan musk-deer (Tragulus javanicus). The transverse extent of the superior true molars is greater than the anteroposterior. The composition of the last molar is like that of the others. The external tubercles are lenticular in section, and the emargination which separates them is apparent on the external face of the crown. The intermediate tubercles are small, and are entirely distinct from the large external tuber- cle. There is a distinct cingulum which is only wanting from the inner base of the crown. The fourth superior premolar has a trilobate outline of the base of the crown, the base of the inner lobe being contracted where it joins the external part of the crown. The internal tubercle is conic, with 46 c 722 THE EOCENE FAUNA. a prolongation outwards and forwards. Intermediate tubercle not distinct. External, anterior, and posterior cingula. The third superior premolar diflfers much in form from that of 3£iodcenus tiirgidiis, although having the same elemental parts. The external portion is extended anteroposteriorly, and has a cutting edge, of which the posterior tubercle forms a lobe. The internal tubercle is quite small, much less than in M. turgidus. A posterior and a weak external cingulum. In the inferior true molars the external tubercles wear into crescents. The crowns increase in size posteriorly. The fifth tubercle of the last molar is rather small, but is well distinguished from the other cusps. The internal median cusp is small, the external median large. The premolars are not so much larger than the true molars in this as in the typical species of the genus. The second and third are more elongate on the base than the fourth. The latter is also less compressed than those that precede it. It has a short wide heel, and a small anterior basal tubercle. In the second and third premolars the posterior edge of the principal cusp is sharp, and descends gradually to the posterior base of the crown. Both have small acute anterior basal tubercles. The first inferior premolar is one-rooted, and has a simple crown directed somewhat forwards. It is separated from the second by a short space. The teeth anterior to this point are lost. Measurements. M. Length posterior four superior molars .0182 Diameters Pm.iv J ''"*'''^''P°«'<'"°'" ^^^ transverse .0042 anteroposterior 0043 transverse 0060 Diameters M.iii^'''^t^''°P°«**'"°' 0''40 ( transverse OOCO Length of inferior molars 0330 Length of inferior premolars 0192 Length of inferior Pm. iii 005.1 Length of inferior Pm. iv 0045 Diameters M.i^ ''"*<='■"?•'"*"■'''•■ "^^^ < transverse 0033 Diameters M. iii ^^°*'"'°P°"*^"°' 0"^2 < transverse 0040 Depth of ramus at Pm. i.. 0047 Depth of ramus at M. ii 0090 AKTIODACTYLA. 723 The centrum of the lumbar vertebra is much depressed, and the base of the diapophysis occupies its entire length. The latter is slightly decurved and directed posteriorly, and its base is concave below. The inferior face of the centrum is not excavated, and is weakly keeled me- dially. The form of the ilium is peculiar, differing from that of most of the Artiodactyle animals with which I have compared it. The rather wide concave anterior face at the inferior part of the peduncle is due to the prominence of the anterior edge, and of a crest on the inner side. The former is prominent just above the usual position of an anterior inferior spine, and then sinks to the edge of the acetabulum. The internal face is narrower than the external, but wider than the anterior. I do not find the anterior face among any of the Ruminantia, except in a modified degree in Antilocapra, nor in any of the Omnivora, excepting in the Phacochcerus^ where it is not so concave. The peduncle is shorter than in Tragulus, and wider than in any of the Suillines or Ruminants which I arn acquainted with. The external face of the great trochanter of the femur is wide. Its apex is a little incurved, and projects further than the head. The neck is deeply constricted from above. The little trochanter is quite prominent. The head is round, and the fossa ligamenti teris, though behind the middle of its inner aspect, looks directly inwards. The external edge of the shaft of the femur is acute; the inner edge is rounded. The rotular groove is rather narrow, and is on an elevated base. Of the lateral crests, one is a little higher than the other near the proximal end. The internal, posterior, and external faces of tha distal extremity of the tibia are flat, the last two sides separated by an angle. The internal face exhibits a shallow tendinous groove. The calcaneum has a wide longitudinal concavity of the external side. It is bounded above by a low ridge, which disappears below the fibular condyle. The cuboid face is oblique vertically and transversely, and is contracted in extent. The external face of the cuboid has a prox- imal concavity and a distal tuberosity running downwards and posteriorly. The external face of the fibula has a ridge which terminates abruptly a short distance above the distal extremity of the bone. 724 THE EOCENE FAUNA. Measurements. K. / longitudinal 0.007O Diameters ceutrnm lumbar vertebrae vertical wZi (transverse 0060 I anterior 0054 Diameters of neck of ilium } exterior 0O7O ( interior ^^ Vertical diameter of acetabulum 00/0 Width of proximal end of femur *'137 Diameter of head of femur 006O Diameter of shaft of femur (transverse) 0065 Width of rotular groove of femur 0045 Width of tibia behind distally - 0054 Distal width of fibula 0045 Length of astragalus 0102 Width of trochlea behind 0048 (length 0070 Diameters of cuboid I . f , ' ' " ' '." ' ' nnjfv I width of middle 0040 From the Wasatch formation of the Big Horn River, Wyoming. J. L. Wortman. Pantolestes etsagicus Cope. Mioclcenus etsagicus Cope. Paleontological Bulletin No. 34, p. 189. Plate XXV e, fig. 21. This, the largest species of the genus, is represented by the two rami of a mandible of an adult animal in good preservation. In their robust character the premolar teeth resemble those of Mioclaenus turgidus, but are not relatively so large, nor is the last true molar relatively so small, as in that species. The heel of the third premolar is obsolete, and that of the fourth is a wide cingulum. Neither exhibits an anterior basal tubercle, and in both the principal cusp is stout. The true molars widen posteriorly to the anterior part of the last molar. The latter contracts rapidly to a narrow heel. The tubercles are all subconic, and the median o-nes of the last molar are small. There are no cingula, and the enamel is smooth. The ramus is not robust, and is of moderate depth. Its inferior border rises below the middle of the last molar tooth, and posteriorly. There is a " mental " foramen below the contact of the fourth premolar and first true molar. Meastirements. M. Length of bases of six posterior molars 0.047 Length of bases of three premolars 024 Length of bases of Pm. ii 009 Length of bases of Pm. iv 008 ARTIODACTTLA. 725 M. Xength of bases of Pm. iv 005 Diameters basis of M. ii J ''"*«''°P''»*®"»'^ 0075 ( transverse 0070 Diameter basis M.iii J '">*""?'"'*«"'"■ ^^* i transverse 0070 Depth of ramus at Pm. ii 0080 Depth of ramus atM. ii 0140 This species is named from the Crow Indian name of the Big Horn River, Etsagie. Discovered by Mr. J. L. Wortman in the Wasatch beds of the Big Horn River, Wyoming. Pantolestes longicaudus Cope. Proceed. Araer. Philos. Soe., 1872, p. 467 (August 3). Plate XXIV, figs. 13-17. Dental formula M. 3; P. M. 4; C. 1 ; incisors unknown. Some of the molars in the only specimen known are so worn as to preclude exact descrip- tion. They evidently possessed anterior and posterior lobes, separated by a valley, which was most expanded on the inner side. The last molar exhibits a short heel posteriorly, which probably supported a small tubercle. The last three premolars are all two-rooted and compressed in form. The fourth presents a crown composed of one large anterior, compressed cusp, and a much lower posterior heel. There is a slight cingulum in front. The canine is lost, but its alveolus indicates that it was a stout tooth. Some caudal vertebrae found with this jaw indicate that the animal possessed a long tail. The mandibular ramus is quite slender, and there is a large foramen below the first true molar; the masseteric fossa is pronounced. So far as the known structure goes, this species resembles the P. chacensis, but pos- sesses a much larger heel of the fourth premolar. The remains of this species were found together by the writer in the Bridger beds on Black's Fork, Wyoming. Pantolestes secans Cope. Bulletin U. S. Geol. Surv. Terrs., F. V. Hayden, 1881, p. 187, Plate XXV a, flg. 6. Represented by the adherent rami of a mandible, on both of which the _posterior four molar teeth are preserved. 726 THE EOCENE FAUNA. ' The species is about the size of the P. chacensis, and hence larger than the P. longicaudus. It diflfers from both in the proportions of its teeth, and especially in the large size and sectorial character of the fourth premolar. The length of the latter exceeds a little that of the third true molar, while in the other species it is shorter. This length is caused by the extent of the anterior basal tubercle and posterior heel. The latter is entirely sur- rounded by a cingulum, and its median line is elevated into a blade, which is continuous with the posterior edge of the principal cusp. The fore and aft edges of the anterior tubercle are also trenchant. The two cusps of the anterior inner tubercle of the first and third molars are well developed, but on the second molar there is but one cusp. This is probably a character to be relied on in distinguishing the species from the P. chacensis. No external basal cingula ; enamel smooth. Measurements. M. Length of last four molars 021 L>ingth of fourth premolar 0068 Elevation of fourth premolar 0040 Length of last true molar 0057 Depth of ramus at first true molar 0070 As is the case with the species of Pantolestes already known, the P. secans seems to have been rare. One specimen was found by Mr. Wortman in the bad lands of the Wind River, Wyoming. PERCOMOEPHI. 727 ADDENDA TO PART FIRST. The following genei-a and species were received too late for insertion in their proper places in the body of the work. The title of Part First should embrace the Puerco epoch with the Wasatch and Bridger. Its fossils were not known at the time when the printing of the title and fii-st pages of the book were in press. PISCES. PERCOMOEPHI. PLIOPLARCHUS Cope. Amer. Journ. Science and Arts, 1883, May-Jnne. The fishes of this genus belong apparently to the Centrai'chine di\'ision of the Percidse, and although the future discovery of the structure of the ventral fins may invalidate this conclusion, I do not anticipate such a result. I am also unable to determine whether there are teeth on the vomer or not. As regards generic affinity, the species do not enter any of the genera now known from American or European tertiary formations, as will be seen from the characters about to be given. They differ from those of the recent genera of Centrarchinse in the entire circular outline of the operculum; and from some of them in the anal fin with five spinous rays originating posterior to the line of the anterior border of the spinous dorsal fin. This new genus I have named "Plioplarchus, with the following diagnosis : Family characters, etc. — Mouth bounded above by premaxillary bone only. Branchiostegal rays seven ; possibl}^ eight. Ventral fin commencing below the base of the pectoral. Scales ctenoid. Generic characters. — Teeth few, simple, and conic. No indication of large pharyngeal bones. Preoperculum entire posteriorly and at the angle; inferior edge unknown. Operculum rounded, entire. One dorsal fin. Anal fin commencing below middle of spinous dorsal, with five or more spinous 728 THE EOCENE FAUNA. radii. Caudal fin openly emarginate. Lateral line continuous, uninter- rupted. Two species of the genus are known, both from some beds of possibly tertiary shale which lie on the Laramie beds in Western Dakota. Plioplarchus whitei Cope. Amer. Jouru. Sci. Arts, 1883, May or June. Plate XXIV g, fig. 1. General form elongate oval, the dorsal and ventral outlines of the body about equally convex. The length of the head enters that of the head and body to the extremity of the caudal vertebrae three times, and the depth of the body at the ventral fins enters the same two and two-thirds times. The muzzle is short and obtuse, and the mouth opens obliquely upwards. The orbit is very large, and enters the length of the head to the border of the operculum three times, and is one-third of itself longer than the muzzle. The radial formula is: D IX- 12; C. -f 17 + ; A. V - 14 ; V. ?; P. 13. All the soft rays are fissured distally. The dorsal spines increase in length to the last one, as do also the anals. The pectoral rays reach to below the sixth dorsal spine, and beyond the extremity of the ventral fin, which does not quite reach the anal. The soft rays of the anal extend to below the extremity of the vertebral column, forming a well-developed fin. The extremity of the soft dorsal is lost. The external rays of the caudal fin are a little longer than the median. The spine of the ventral fin is not strong. The caudal peduncle is moderately nan-ow. The vertebral column is convex upwards anteriorly. Its vertebrae are, caudal XVI; abdominal XII; to the edge of the operculum. A caudal vertebra preserved in place has two lateral fossae, separated by a horizontal keel. The abdominal cavity extends postei'ior to the anterior spinous rays of the anal fin, so that the anterior interhsemals are directed upwards and backwards. The ribs are long. There are four intemeural bones anterior to the dorsal fin. The postcoracoid is elongate. There are seven or eight longitudinal rows of scales visible above the ver- tebral column, and sixteen below it, the size diminishing rapidly downwards. All the bones of the head excepting the muzzle and jaws are covered with PERCOMORPHl. 729 scales. There are six rows on the cheek below the eye. The scales of the body have the basal radial grooves and ridges few and coarse. The external surface is finely but strongly rugose with tubercles or grains, with a trace of fine concentric lines near the superior and inferior edges. Marginal denticles small. The interior faces of the scales which cover part of the fossil display numerous very close and fine concentric lines, with a small triangular rough area extending from the edges toward the center. Measurements. u. Total length with caudal fin 116 Deptb at front of dorsal fin 033 Length of caudal fin to last vertebra 0247 Length of caudal vertcbrse 0365 Length of base of dorsal fin 0325 Length of base of soft dorsal 015 Length of seventh dorsal spine 017 Length of third dorsal ray .020 Length of fifth anal spine 0165 Xiength of fourth anal ray 022 Length of base of anal fin 0245 Length of pectoral fin 020 Length of ventral fin 017 Depth of caudal preduncle 012 Depth of head at orbit posteriorly 026 The typical specimen of this fish is in excellent preservation. The species is dedicated to Dr. C. A. White, the distinguished geologist and paleontologist. Plioplarchus sexspinosus Cope. Amer. Journal Sci. Arts, 18S3, May-June. This species is represented by two specimens, both of which lack the tead and body anterior to the dorsal fin. One of the specimens is accom- panied by its reverse. The differences between this species and the P. whitei are to be seen in the radial formula. This shows more numerous spinous and less numerous cartilaginous rays. The formula is: D. X-13 ; C. + 17 -}-; A. VI-9. The last anal radii are somewhat injured, and there may have been more than nine, but no traces of others exist, and it is clear that they were less numerous than in the P. whitei. There are about eighteen series of scales Lelow the vertebral column at the front of the dorsal fin. Their external 730 THE EOCENE FAUNA. surfaces are not so rough as in the P. wMtei, as the granules are confined to the center of the scale, and the concentric lines are much more obvious and form a wider border. Ctenoid denticles distinct. Caudal fin openly emarginate. Meas^lrements. Depth of anterior edge of anal fin 0206 Length from anterior edge of anal fin to end of caudal vertebrae 0305 Length of caudal fin to vertebral centra 020 Length of base of dorsal fin 0282 Length of base of soft dorsal 015 Length of base of anal - 017 Length of base of spinous anal 008 Length of ninth dorsal spine 013 Length of fifth anal spine 015 Depth of caudal peduncle (about) - Oil Remarks. — Among the known extinct genera of fishes it is Mioplosus Cope that approaches nearest this one. The former is characteristic of the Green River beds of the Lower Eocene. The genus Plioplarchus does not enable me. to identify the horizon from which it is derived, with any of our known formations. It only permits the general statement that its age may be tertiary or upper cretaceous. REPTILIA. OPHIDIA. HELAGRAS Cope. Proceedings Amer. Philosoph. Society, 1883, p. 545. The generic characters are drawn from vertebrae only. These display a modified form of the zygosphen articulation, as follows : The roof of the zygantrum is deeply notched on each side of the median line, so as to ex- pose the superior lateral angles of the zygosphen. This separate median portion of the roof of the zygantrum forms a wedge-shaped body, which may be called the episphen. It is surmounted by a tuberosity, which con- stitutes the entii'e neural spine. The latter is thus entirely different in form from that of other serpents. Articular extremities of centrum round, the ball looking somewhat upwards. Costal articulation 8-shaped, the surfaces OPHIDIA. 731 convex and continuous. Hypapophyses none on the two vertebrae pre- served. Zygapophyses prominent. Free diapophyses none. This genus is readily distinguished by the presence, first observed here, of the episplien in addition to the zygosphen, and by the pecuhar form of the neural spine. We have now several vertebral articulations originally discovered in American vertebrata. These are the episphen, as above; the hyposphen, which characterizes the Opisthocoelous Dinosauria {Sauropocla Marsh), and the Diadedidce of the Permian period ; and the zygantrapophysis, which is present in the Diplocaulid family of Batrachia.^ Helagras prisciformis Cope. Proceeds. Amer. Philosoph. Society, 1883, p. 545. Plate XXIVg; fig. 2. A section of the vertebra at the middle is pentagonal, the inferior side slightly convex downwards. The lateral angle is the section of the angular ridge which connects the zygapophyses. The episphen has a shallow rounded groove on its infero-posterior side, which is bounded by a project- ing angle on each side at its middle. The episphen does not project so far posteriorly as the postzygapophyses, and the degree of its prominence dif- fers in different parts of the vertebral column. In one of the two vertebrae in my possession its prominence is small. The tuberosity on its summit is a truncate oval with the long diameter anteroposterior, and equaling two- fifths the length of the arch above. It is elevated above the rest of the median line, which is roof-like, with obtuse angle. The tubercular articular facet is entirely below the prezygapophysial surface, but the free part of the prezygapophysis extends well in front of it. It is distinguished from the capitular surface by a very slight constriction. A slight ridge extends from the capitular articulation to the edge of the ball of the centrum. Below this, the surface is slightly concave, and the middle line is gently convex. The latter terminates in an obtuse angled mark just in front of the edge of the ball. This edge is also sHghtly free from the ball. The capitular costal surfaces do not project inferiorly quite to the line of the inferior surface of the centrum. iPaleontological Bulletin No. 35, Nov. 11, 1883. 732 THE EOCENE FAUNA. Measurements of a vertebra. M. Length of centrum (with ball) 0070 rv- » r 1 11 < vertical 0035 Diameters of ball < „„,„ ( transverse wifj Elevation of vertebra at epispheu 0085 Elevation of vertebra at middle 0062 Width at prezygapophyses 0120 Width of tubercular costal faces - 0105 Width of zygantrum 0058 Vertical diameter costal faces 0040 Transverse diameter tubercular costal face 0028 This snake was about the size of the black snake, Bascanium constrictor. It is an interesting species for two reasons. First, it is the oldest sequent known from North America. Second, in the imperfection of the zygantrum we observe prominent, narrowed forwards, border with several teeth ; posterior lobe dentate; marginals wide, mucronate T. laticuneus. Lip prominent, with parallel sides and entire margin ; marginals wide, with notched border T. ligonius. Lip not prominent, truncate, entire; marginals wide, notched medially. . T. amphithorax. None of the varieties of the Stylemys nehrascensis present the well-defined lip of the plastron seen in these species, nor do its marginal bones ever have TESTUDINATA. 763 the projecting mucros or the step-like notches described above. In the T. laticuneus I have observed the tarsus and metatarsus. The latter is com- posed of much shorter bones than the corresponding ones in Stylemys, lead- ing to the supposition that it has the shoi-t phalangeal series of the family Testudinidce} The positive determination of this point remains for future investigators. Testudo cultratus Cope. Paleontologioal Bulletin No. 15, p. 6, August 20, 1873. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 511. Plate LXIII; figs. 1-3. Parts of two individuals of this species were obtained by my expedi- tion of 1873. This is the smallest of the five species of Testudo, having about the average size of the Stylemys nebrascensis. This is indicated by the costal and marginal bones which accompany the portions of plastron of both speci- mens. The width of the lip at the base is also less than that of any of the other species, but the length and thickness are remarkable as compared with the other dimensions. The width and thickness at the base of the lip are nearly equal; both dimensions diminish to the apex, which is obtusely acuminate. The superior face of the lip is gently convex in both dimen- sions. The inferior surface is plane anteroposteriorly ; transversely it rises to the external edge, which is subacute. The suture of the gular scutum is directed posteriorly, giving the usual triangular form. The thickness of the Hp is abruptly reduced above, where the surface descends to the meso- sternal bone. The lip of one of the specimens is fissured deeply, in an eccentric manner, on both sides of central core. Whether this or the unfissured con- dition is characteristic of the species or not, is uncertain. It appears to be homologous with the dentation in the lip of T. laticuneus. The marginal bones are robust, and are much thickened below. The edges of those of the posterior margin are acute, while those of the anterior border are obtuse, thus differing from those of T. laticuneus, where they are acute. At the points where the dermal sutures reach the margin, both 'See page 109 of this work, where the families of Testudinata are characterized. 764 THE WHITE EIVER FAUNA. specimens are unfortunately broken in every instance, so that the question of notches or mucros cannot be decided. The costal bones are moderately thick, and alternate in width, narrower and wider. The dermal sutures do not display raised margins. The anal marginal bone is wedge-shaped, with the posterior margin representing a truncate apex. Its surface and margin are convex, and the anterior sutural margin is concave. A fragment, which is in all probability the posterior lobe of the plas- tron, is characteristic. It is thick, and its inferior face is somewhat recurved posteriorly. The outline of the margin presents a pronounced obtuse angle, and the edge is several times abi'uptly notched. Measurements of No. 1. M. ( at base 1^"^"'=='^ "^^^ Diameters of half of lip i ( transverse 043 ( length outer edge 056 Diameters second marginal from anal < ^ < width 030 Length free margin of anal 026 Width of anal above 050 Thickness of a vertebral bone .011 Thickness of a costal at middle 009 Found by myself near the head of Horse Tail Creek, in Northeastern Colorado. Testudo QUMiRATUs Cope. Plate LXI; fig. 5. This tortoise was, perhaps, the largest of those of the White River beds. It is, unfortunately, only represented so far in my collection by the lip of the plastron and by an imperfect marginal bone. The former frag- ment indicates clearly a species quite unlike the others here described. The lip is thick at the base, and the superior surface descends gradu- ally to both anterior and lateral edges. The middle of the former is notched, but there are no other indentations of importance. The lateral borders do not converge, as in T. laticimeus, but rather diverge, as in Hadrianus octo- narius. Its form is more like that of T. Ugonius than any other species, but it differs- from it and from all other species known to me in the absolutely transverse posterior gular suture. The suture follows an angular groove, which cuts the lip off from the inferior surface of the plastron, which lies behind it. The latter swells prominently behind the suture, but less so at TESTUDINATA. 765 the middle line than laterally. The marginal is probably the nuchal, and displays a part of the nuchal scute. The latter was at least not very narrow, and its free edge is concave. The borders of the dermal grooves are raised. Measurements. M. Length of lip from gular groove 070 Width at base ■. 120 Thickness at base 02i> Length of nuchal scute 041 Head of Horse Tail Creek, Northeastern Colorado. Testudo laticuneus Cope. Faleoatological Bulletin No. 15, p. 6, August 20, 18T3. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 511. Plate LXI; fig. 1. A number of fine chelonites which I obtained during my expedition of 1873 are, unfortunately, not accessible for description at present. Among these will probably be found some of the specimens of this tortoise, to which my original description refers. One individual, in a good state of preserva- tion, must serve as the basis of the present description. It is, however, one of the, best which I procured, although a little distorted in some places by pressure. The general form is broad and depressed. The anterior and posterior outlines of the carapace are subtransverse, the former being nearly straight and the latter a little convex. The lip of the plastron projects much beyond the anterior border of the carapace, while the posterior lobe is included within that of the carapace. The free marginal bones ai-e straight, but few of them being a little concave on their superior face. The anal bone is truncate wedge-shaped, with the free edge and the general surface gently convex. When the dermal scutal sutures reach the margin, there is a short acute mucro on both anterior and posterior marginal bones. There are na keels -nor tuberosities on the carapace. The plastron is rather flat, indicating a female animal. The anterior lip is large, and each half is rather longer than it is wide at the base of the external side. The exterior borders converge anteriorly, leaving a short margin, which presents six strong teeth, three on each half, of which the adjacent median ones are the widest. The posterior lobe is divided by a. 766 THE WHITE EIVER FAUNA. deep notch into two rounded lobes, whose border is notched three times, leaving four teeth of smaller size than those of the lip. The lateral suture of the nuchal marginal bone is much less oblique than in T. amphithorax and other species. The entosternal bone has eight sides. It is as wide as long, and narrows forwai-ds. The dermal sutures are grooves with raised edges. This character is quite marked, and cannot be looked upon as indicating immaturity, as the animal is evidently adult. The nuchal scute is as wide as long, offering a strong contrast to that of T. ligonius, where it is long and narrow. Its lateral sutures terminate in mucros, which leave a concave margin between them. Vertebral scuta a little longer than wide. The anal scutum has a straight superior border, and is twice as wide as long. The gular scuta have a very oblique poste- rior border, and each one is about as long as the external free edge of the lip. The humero-pectoral suture retreats abruptly backwards from the free humeral border before becoming transverse. At its middle it is as far anterior to the pectoro-abdominal suture as the latter is from the abdomino- anal, thus leaving a much wider pectoral scutum than is found in T. ligonius and T. amphithorax. Measurements. M. Length of carapace (axi.iU ^^^ Width of carapace (axial) 35t) Length of plastron (greatest) 438 Width of base of anterior lobe ~00 Width of base of lip 085 Length of lip on external edge 045 Greatest length of posterior lobe (axial) m Width of posterior lobe at base - 200 Width of anal marginal above 070 Width of anal marginal on margin 037 Length of nuchal scute 027 Length of second vertebral scute 032 Width of second vertebral scute 080 From the head of Horse Tail Creek, Colorado. Testudo ligonius Cope. Paleontological Bulletin No. 15, p. 6, August 20, 1«73. Annual Report U. S. Geo!. Surv. Terrs., 1873 (1874), p. .511. Plate LXI; figs. 2,3. Parts of carapace and plastron of one specimen represent this species in my collection. In the locality where I found this and most of the other specimens of tortoises from the White River beds here described, specimens TESTUDINATA. 767 were very numerous. My means of transportation being limited, I could not collect a full series, but selected diagnostic bones from the best examples for purposes of future study. Of the present individual I have the clavicle ("episternal"), nuchal vertebral, several marginals, part of pectoral, and basal part of half of posterior lobe of plastron. This is a large species, with the marginal bones and edges of plastron thickened. The lip is produced, and has parallel sides and a truncate free edge without denticulations. The angle at which the borders would meet if produced, is obliquely cut off. The inferior surface is deeply, openly grooved along the oblique line of the gular dermal suture, and is excavated on the middle sutural line just ante- rior to the mesosternum. The superior face of the lip slopes outwards, and is, swollen laterally behind. The free marginal bones of the carapace are not recurved at the margin. There is a projecting angle or point where the dermal suture reaches the margin, which is immediately followed by a step- like notch of little depth. The lateral suture of the gular scute on the upper side of the lip is nearly parallel with the median suture, giving thus a paralellogramnic outline. The nuchal scutum is long and narrow, and is not bounded on the edge by mucros. The pectoral scutum is very narrow. Measurements. M. Length of lip on external edge 035 Width of half of lip at base 046 Thickness of lip at base 023 Width of a free posterior marginal 082 Length of a free posterior marginal 072 Width of posterior lobe plastron at base.... 1^^ Anteroposterior width of pectoral scute 018 Length of nuchal scute 040 Width of nuchal scute 008 Head of Horse Tail Creek, Colorado. TeSTUDO AMPHllHORAX Cope. Paleontological Bulletin No. 15, p. 6, August 50, 1673. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 511. Plate LXI; fig. 4. Of this large species I have before me two specimens which display the anterior lobe of the pla.stron, and probaby a third which does not in- •clude that diagnostic part. 768 - THE WHITE EIVER FAUNA. The T. amphitliorax agrees in many respects with the T. Ugonius, but difi'ers much in the characters of the anterior lobe of the plastron. There is scarcely any lip, but the margin is truncate, with a bounding angle on each side to represent the usual margin of the lip. In one specimen this angle is much rounded. The inferior surface differs from that of T. Ugonius in being without impressed groove in the line of the gular suture and median fossa. In these respects it resembles T. laticuneus. One anterior lobe was found with the posterior lobes of two individuals, which are exactly alike. This lobe was deeply emarginate, and each sublobe is broadly rounded, wedge-shaped, with thin edge, with a notch in it at one point. The margin becomes very thick near the groin. The relations of the inferior and superior bounding gular scuta are dif- ferent in this species from what is seen in T. Ugonius. The superior groove has the posterior position appropriate to a long lip, Avhile the inferior leaves the margin much anterior to that point, and just posterior to the angle which bounds the very short lip which the species actually possesses. The two sutures nearly correspond in position in the T. Ugonius. The pectoral scutum is quite narrow in the specimens, as in T. Ugonius. The scutal sutiires are impressed and do not have raised borders. The edges of the marginals are all injured in the specimens. The mesosternal bone is a little wider than long. It is more contracted anteriorly than posteriorly, but the lateral angles are about opposite the middle of the length. The costal and vertebral bones are rather thin. A marginal bone, probably one of those in contact with the anal, has a peculiar form, such as does not exist in any other species, unless it be the T. Ugonius and T. quad- ratus, where I have not seen it. It is recurved at the sutural edges, or is con- cave at the middle, so as to be openly trough-shaped. This indicates a very convex anal marginal bone, and a doubly sigmoid flexure of the free margin behind Measurements. No. 1. M. Widtt of truncate lip 080 Width of humeral scute fore and aft 024 Length of posterior lobe on axial line of a half 151 Width of base of posterior marginal lobe of plastron 092 Length of axial of trough- shaped marginal (anteroposteriorly) 072. TESTUDINATA. 769 No. 2. U. Width of lip 089 Width of mesostemnm 103 Length of mesosternum 096 Width of anterior lobe at base 210 Length of anterior lobe (axial) 125 Thicknees of a costal bone 080 Head of Horse Tail Creek, northeast Colorado. STYLEMYS Leidy. Cope diagnosis, Transactions Amer. Philos. Society, XIV, 1866, p. 123. This genus probably belongs to the Emijdidce, in the neighborhood of Manuria, now existing in Eastern Asia. It is characteristic of the American lacustrine Miocene, but is represented by very few species. Stylemys nebrascensis Leidy. Report U. S. Geol. Surv. Terrs., I, p. 224, 1873. Proceed. Acad. Phila., 1851, p. 172. Testiido hemit- pherica, T. oweni, T. ciilbersom, and T. lata, Ancient Fauna Nebraska, 1853, 105-110. PI. XX-XXIV. I obtained this species in Northeastern Colorado, in the White River formation, with the Tortoises already referred to the genus Testudo. Some of the specimens are of large size, others small. I have also numerous well-preserved chelonites from the John Day River beds of Oregon, which I refer to the same. Many of the Oregon specimens differ in some respects from the typical forms of the S. nebrascensis, but the characters are not constant. I observe three principal characters of the smaller and medium-sized specimens from Oregon. These are, first, the greater trans- verse length of the first marginal dermal scutum. This is caused by the more external position of its external bounding suture ; instead of being nearly continuous with the lateral suture of the first vertebral, it is some distance external to it. This I find in all the Oregon specimens. Second, the less abrupt posterior flexure of the pectoro-humeral suture where it leaves the free margin of the anterior lobe on each side. A large Oregon specimen has the recurvature nearly as abrupt as in the Colorado and Nebraska specimens, and Leidy figures one of the latter (Ancient Fauna of Nebraska, PI. XX), where the recurvature is as in some of the Oregon specimens. Thirdly, a convexity of the pygal and anal bones. This does 49 0 770 THE WHITE EIVEE FAUNA. not appear in a very large and a very small specimen. It may be charac- teristic of the male sex. One of the Oregon specimens is much larger than the others, and has the anterior lobe a little more produced, in this respect resembling the largest Colorado specimen. I add the measurements of these two specimens: Measurements. No. 1. — Colorado. It. Length of plastron 390 Widtli of plastron at middle '. 310 Width of anterior lobe at base 200 Length of anterior lobe 145 Elevation of carapace 210 No. 2. — Oregon. Length of plastron 420 Width of plastron at middle 345 Width of anterior lobe at base 215 Length of anterior lobe 157 Elevation of carapace 1*0 The Oregon form has been regarded by Leidy as a distinct species, with the name Stylemys oregonensis* He adduces the thinness of the verte- bral bones as its distinctive character. For the present I cannot admit it as more than a variety, although the skull and feet must be known before its position can be finally decided. LACEEIILIA. Several species of this order were discovered by myself in the White River beds of Coloi'ado in 1873, and a single species was found by one of my parties in the John Day beds of Oregon. With the exception of the Pelto- saurus granulosus they rest upon fragmentary remains, which are in some instances not sufficient to furnish evidence of the position of the species in the system. The genera which are determinable display affinity to types now existing in the warmer parts of North America. •Report U. S. Geol. Surv. Terrs., I, p. 225. LACERTILIA. 771 PELTOSAURUS Cope. Paleontological Bulletin No. 15, p. 5, August 20, 1873. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 572. Premaxillary undivided, with spine ; a zygomatic, postorbital, and parieto-quadrate arches. Parietal bones united. Teeth pleurodont, with obtuse, compressed crowns, of similar form on all the jaw-bones. Body covered with osseous scuta, which are united laterally by suture. Vertebrae depressed, without zygosphenal articulation. Median hexagonal dermal scuta on the parietal bone. There are sufficient remains of the typical species of this genus to furnish a basis for an estimation of its affinities, a point of some interest, as this has been seldom if ever done in the case of a terrestrial lizard of the Miocene epoch. The primary group to which it is to be referred is not difficvilt to determine.^ The frontal and parietal bones are each undivided, and there is no fon- tanelle in either, or in their common suture.^ There is a large postfrontal, and the usual cranial arches are present, and the quadrato-jugal absent. The frontal possesses strong lateral inferior crests, but whether they under- ai-ch the olfactory tube completely, the specimen does not show. All the usual elements of the mandibular ramus are present, but the angular is very narrow. The dentary does not extend behind the coronoid on the external face of the jaw. The coronoid is little produced either forward or back- ward above, but sends a process forward on the inner face of the dentary. The splenial is well developed, but becomes very slender anteriorly ; it covers the meckelian groove, except for a short space distally, where it furrows the inferior aspect of the jaw. The surangular is quite peculiar; it is massive, and lacks the usual deep fossa for the pterygoid muscle, and has a broadly truncate superior margin. It is in the same vertical plane as the dentary, and not oblique or subhorizontal as in most Gecconidce. The den- tal foramen is small, and pierces its inner face. The posterior angle of the ramus is broken off. 'See the author's Osteological Characters of the Scaled Reptiles, in Proceedings Academy Philadel- phia, 1864, p. 224. -What I originally thought was such is a foramen-like sinus in the posterior margin of the parietal. 772 THE WHITE EIVEE FAUFA. The characters of the preniaxillary bone, fontanelle, dentition, coro- noid, dentary, splenial bones, and meckelian groove, place this genus out of the pale of the acrodont families. The parietals and vertebrae are dis- tinct from anything known among the geccos. There is no resemblance in essentials to the Amphishcenia, so that we must look for its place among the numerous pleurodont families. Here the absence of the knowledge of the periotic bones and sternum somewhat embarrasses us; but other indica- tions are clear. The coincidence of the want of parietal fontanelle with the lateral frontal plates refers us at once to the Leptoglossa or Diploglossa ; a reference confirmed by the simple frontal, and strong cranial arches. The massive form of the surangular bone, and reduction of the angular, at once distinguishes Peltosaurus from any known family of the tribe Leptoglossa, and constitutes a point of near resemblance to the GerrJionotidoe. This ap- pears to be a real affinity, which is further confirmed by the presence of a symmetrical dermal scutellation on the top of the head. Eeferring Peltosaurus, therefore, provisionally to the Gerrhonotidce, it remains to consider the generic characters. The temporal fossa was not roofed over by true bone, though the border of the postfrontal encroaches on it ; and it is rather small. The orbits, on the other hand, are large, and the malar bone forms a segment of a circle. The parietal thins out behind, and its posterior border has a subround excavation. Thetwo median der- mal scuta, which left their impressions on the parietal bone, represent the interparietal and postinterparietal plates respectively ; the latter especially characteristic of the Gerrhonotula', and not found in leptogloss or diplogloss families generally ; those possessing it being the Lacertidce in the former, and Anguidce in the latter. The most prominent character which distin- guishes this genus from Gerrhonotus is the existence of the osseous scuta which covered the body. Even the form of these is similar to the corre- sponding dermal scuta of the existing genus. They are rectangular and are arranged in transverse bands on the body, those of one row overlapping the bases of those of the next row posteriorly, or imbricated. The scuta of each row are joined on their long sides. By minute suture. LACERTILIA. 773 Peltosaurus granulosus Cope. Paleontological Bulletin No. 15, p. 5, August 20, 1873. Annual Beport U. S. Geol. Surv. Terrs., 1873 (1874), p. 513. Plate LX, figs. 1-11. I took numerous parts of the skeleton of an individual of this species from the White River chalk-bed on Cedar Creek, in Northeastern Colorado, during my expedition of 1873. The cranial fragments include the premax- illary and jjarts of both maxillary bones ; the malar of one side ; the coos- sified frontals and parietals sejiarated from each other. Also the greater part of both mandibular rami. There are several vertebras, and many dermal scuta. The parietal is a wide element, and has a nearly plane superior surface. The granular sculpture vanishes posteriorly, leaving a wide, smooth band at "the posterior border of the bone. The scutal arese are rather narrow, each one longer than wide, and occupying just half of the length of the granular portion of the surface. The frontal suture is perfectly straight. The frontal l)one is longer than Avide, and is slightly convex in both directions. The greater part of it is preserved, and displays no dermal scuta, hence the frontal al scutum was large and undivided. The lateral olfactory ridges are mas- sive and not very deep, being much thicker than in Exostinus serratus, and are strongly beveled on the external side ; that is, to the supraorbital border. The malar and postorbital bones together form a rather slender arc of a circle, indicating a large orbit. The premaxillary bone has a wide, flat spine, ■which is so strongly inclined as to be nearly horizontal. No portion of it protrudes beyond the alveolar border, which supports seven teeth. There is a foramen at the base of the spine on each side. The external surface of the premaxillary is entirely smooth. On the external face of the maxillary the usual foramina occur at the usual intervals. In the mandible the post- dentary parts are extended, about equaling the dentary (the angle is bro- ken from both rami), and are robust. The anterior fourth of the meckelian groove is exposed. The external face of the dentary is convex, and is pierced by five foramina, all in the anterior half. The superior aspect of the surangular region is truncate or flattened, with angles separating it from the lateral faces, as in other Gerrhonotidce. 774 THE WHITE EIVEE FAUNA. There are ten teeth in .10™ of the maxillary bone, and there are twenty-four in the dentary bone. All are closely placed. Those of the superior series are a little more robust ; their inner faces are convex, giving the shaft a slight curve in profile. The apices of the teeth are not expanded, but are wedge-shaped, with a cutting edge in the long axis of the jaw. A strong bevel of the crown to the external maxillary face gives their apices an especial robustness. Under the microscope their surface is delicately parallel-wrinkled to the cutting edge. The scuta are parallelogrammic in form, and their proximal or con- cealed portions are from one-fourth to one-third the entire length. The granulation is like that of the cranium, fine and without distinct pattern. The centra of the vertebrae are moderately depressed, those of the dorsal region the most so, and with the greater part of the face of the ball looking upwards. These centra are not ridged on the middle line below, but are slightly convex in transverse section. On either side, behind the inferior extremity of the parapophysis, is an oj^en, shallow groove looking down- wards, and defining the middle region as a wide band. Above, this groove is bounded by an obtuse longitudinal ridge, and above the ridge occupying the side of the centrum is a concavity. This is bounded above by the prominent ridge that connects the zygapophyses. The transverse process is vertical and narrow ; it is nearly sessile and is not subdivided. A verte- bra inclosed in matrix close to the skull is probably from the anterior part of the series. Its centrum is not so depressed as in those already described, and it has a strong hypapophysial keel. Its ventral spine is rather elevated, and is grooved posteriorly. As compared with the so-called Placosauridce of the Eocene foi-mation, this species presents various points of resemblance, which the descriptions of the former do not yet permit us fully to estimate. The presence of regular cranial scuta will distinguish Peltosaurus from the known forms as a genus. The granulation of the cranium and osseous scuta, is finer than in any of the Eocene species I have met with. Measurements. M. Meilian width of parietals 0.0140 Median width of frontals 0080 LAOEETILIA. 775 M. Length of mandibular ramus to cotylus .0400 Diameter of vertebral centrum (transverse) 0030 Length of vertebral centrum 0055 Length of a dorsal scutum 0075 Width of a dorsal scutum 0042 About the size of the Heloderma suspedum. EXOSTINUS Cope. Synopsis of New Vertebrata Colorado, 1873, p. IG. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 511. This form of lizard is represented principally by a nearly entire frontal bone. Close to it were found a zygomatic bone and a nearly com- plete dentary bone, with the teeth. The former is in all respects appro- priate to the frontal bone, and the size of the dentary bears the usual relation of size to the same. Its dentition is appropriate to the affinities of this genus to Peltosaunis Cope. The frontal bone is much narrowed between the orbits, as in recent leptogloss Pleurodonta, while the olfactory lobes were almost as completely underarched as in the thecagloss-type. The stout, well-developed zygomatic, with malar process, resembles the former group, and the teeth have a similar structure. These are closely placed, truly pleurodont and subcylindric. The crowns are simple, compressed, and with a convex edge. They are similar in form throughout the dentary bone. Cranial bones covered with • symmetrical osseous prominences. The sculpture of the superior surface of the frontal bone is more like that of the genus Anolis than any other known to me. The prominent inferior lateral olfactory crests, are, however, entirely inconsistent with any such affinity, excluding the genus from the Iguanian group altogether. It coincides with the evidence furnished by the forms of the teeth, that the genus Exosthms is one of the Diploglossa^ and allied, but not very closely, to Peltosaurus. In the latter the frontal region is much wider, and is not covered with tubercles, and the olfactory ridges are much less prominent. In its narrow interorbital region Exostinus differs from any recent genus of the order known to me. 776 THE WHITE EIVER FAUNA. EXOSTINUS SEERATUS Cope, Locia citatia. Plate LX; figs. 12-14. A series of tubercles along each supraorbital border, longitudinal at the front, and quadrate at the back part of the eyebrow. A single series of tubercles separates them. Five tubercles in a transverse row at the posterior margin of the frontal. Two series of flat tubercles on the zygomatic bone. Dentary quite convex on outer face ; inner face slightly convex ; 8 teeth in 0 .0050. Measurements. ii. Length of frontal (nearly complete) 0.0070 Width of frontal posteriorly 0034 Width of frontal at postorbital point 0045 Width ef frontal between orbits 0018 Length of zygomatic 0070 Depth of dentary at last tooth 0030 Length of a mandibular tooth 0018 About the size of the large males of the northern Anolis principalis. ACIPRION Cope. Synopsis New Vertebrata of Colorado, 1873, p. 17. Annual Report U. 8. Geol. Surv. Terrs., lB73 (1874) p. 514. Represented by a dentary bone, with nearly all of the teeth remaining. A groove, apparently the Meckelian, extends along the inferior border of the distal half of the bone. The teeth are truly pleurodont, closely placed, and cylindric, with compressed crowns. The latter supports a large median and two small lateral cusps, three in all. ACIPRION FORMOSUM CopC. Lo(Aa citatia, Plate LX; fig. 15. The crowns project well above the alveolar border. External face of dentary smooth, with rather distant foramina. Ten and a half teeth in o-^.ooso. Measurements. M. Depth of dentary at middle 0.0022 Length of a median tooth 0018 Elevation of same above alveolus 0010 LACERTILIA. 777 This species is about the size of our Cnemidophori. From all the genera of this group, Aciprion differs in the uniform character of the teeth, there being no simple teeth in the front of the series so far as preserved. A jaw- fragment probably represents a second species of this genus. A well-pre served lower jaw of the Aciprion formosum was obtained in Dakota by the Princeton Expedition of 1882. DIACIUM Cope. Synopsis New Vertebrata Colorado, 1873, p. 17. Annual Report U. S. Geol.Surv. Terrs., 1873 (1874), p. 514. This genus was originally established on the sacral vertebra of a liz- ard which displayed the peculiarity of the absence of any trace of neural spine. The diapophysis is subcylindric and elongate. Centrum concave below ; neural arch flat above. Articulation without zygosphene or rudi- ment of it ; zygapophyses oblique, the arch deeply excavated between the anterior ones. Obliquity of ball inferiorly. DiACIUM QUINQUIPEDALE Cope. Loda citatis. Plate LX; fig. 20. Two obscure hypapophysial tubercles below the ball. Centra slightly depressed, the cup excavated above and below. An angulation extends backwards from each anterior zygapophysis; the neural arch between them flat on the anterior half , Measurements. M. Length of centrum below 0.0100 ^. . J. .■ I < transverse 0086 Diameter of articular cup ■; . . , ,„^ , ( vertical 0064 Diameter of base of diapophysis 0044 Width between anterior zygapophyses 0098 Width of upper plane of neural arch 0078 This species is as large as any of the existing species of Iguanidce. PLATYRHACHIS Cope. Synopsis New Vertebrata Colorado, 1873, p. 19. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), 516. This genus is known only from vertebrae, which, though abundant in the White River beds, I have been as yet unable to connect with other 778 THE WHITE RIVER FAUNA. portions of the skeleton. The genus was founded on the supposition that the typical species, the P. cohradoensis, possesses the zygosphene articulation, a character which I have since been unable to verify, and do not now believe in. The subtraction of this character leaves little for the genus to stand on ; but I retain the name with the following definition : Vertebral centra with the articular faces much depressed, and without inferior or lateral carinse. The ridge connecting the zygapoph3'ses deeply incised. Neural spine a low keel. The incised interzygapophysial ridge distinguishes these vertebrae from those of Peltosaurus. The two best known species may be distinguished as follows : Much smaller ; ueural spine not ending in a knob; costal articular face principally convex P. cohradoensis. Much larger; neural spine ending in an obtuse apex posteriorly; costal articulation, superior part concave P. rhamhastes. A third species is only known from a sacral vertebra. Platyrhachis coloradoensis Cope. Locis citaiis. Plate LX; fig. 17. The inferior face of the centrum in four dorsal vertebrae is plane, and is separated by an obtuse right angle from the nearly vertical lateral sur- faces. Neural arch depressed, an angle connecting the zygapophyses. Neural spine a keel, projecting beyond the posterior margin in a mucro. Ball truncate below its convex face, looking sliglitly upward. Costal capitular surface semiglobular, directly below the anterior zygapophysis. Neural arch concave between zygapophyses. Measurements. M. Length of three dorsal vertebrie 0.0070 Length of one dorsal vertebra 0028 „• ,. j-i 1, < transverse 0014 Diameter ol ball < . , „.„. < vertical 0006 Elevation of vertebra 0019 Width betvfeen zygapophyses 002,') This species is of small size, not exceeding the red salamander (Si)elerpes ruber) in dimensions. From Horse Tail Creek, Northeastern Colorado. LACEETILIA. 779 Platyrhachis unipedalis Cope. JHacium unipeddle Cope. Synopsis of New Vertebrata of Colorado, 1873, p. 18. Cremastoeaurug unipe- dalis Cope. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 516. Plate LX; fig. 19. Represented by a sacral vertebra of an individual much larger than any of those of the last-described species, and a little smaller than those of the species next following, characterized by the unusual protuberance of the articular ball and absence of flattening of the centrum below. Centrum depressed ; plane longitudinally convex in transverse section. An annular groove round the ball. Diapophysis elongate, slightly depressed. Measurements. M. Length of centrum 0.0034 Diameter of cup ^t™"^^^'"^^ ■ 00=^" i vertical 0018 Were this vertebra part of an individual of the P. rhamhastes, its articu- lar faces would have been more rather than less depressed than the dorsal vertebrae which represent it. From Horse .Tail Creek, Northeastern Colorado. Platyrhachis rhambastes Cope. Plate LX ; fig. 18. Established on seven dorsal vertebrae, which I formerly regarded as belonging to the Cremastosaurus carinicollis. (Annual Report U. S. Greol. Surv. Terrs., 1873 (1874), p. 515. They differ very much from the cervical vertebrae on which the latter genus is based ; too much, I believe, to render it probable that they belong to lizards of the same genus. Tliis also in spite of the fact that the difference is someAvhat like that which pre- vails between cervical and dorsal vertebrae of many genera of Lacertilia. The inferior carina in the Cremastosaurus is not a hypapophysis of tlie usual kind found on only a few of the cervicals, but continues undiminished to the sixth and last I possess of the series. The articular ball at this point shows no indication of the depression characteristic of the dorsals, and which is usual at this point, even in species where the anterior cervicals have subround articular extremities. 780 THE WHITE RIVER FAUNA. The dorsal vertebrae have transversely-oval articular faces, and centra without inferior keel or ridge. The vertebrae are all dorsal, hence the diapophyses have the usual form in the order for costal articulation, and do not project as far inferiorly as the plane of the lower face of the. centrum. It does not project beyond the anterior zygapophysis, and the lower half is especially developed as the costal condyle. The sides are separated from the wide, flat, inferior surface by an obtuse angle. Neural spine a keel extending from the front of the arch and rising into a short obtuse apex above the articular ball. There is a collar round the ball, which is faintly visible on the inferior side. Measurements. M. Length of centruni COIMO Width of cup 0018 Depth of cup 0010 Elevation of neural arch anteriorly 0015 Elevation of neural spine and arch posteriorly 0043 Total expanse in front 0047 The dorsals represent several individuals. Horse Tail Creek, Northeastern Colorado. CREMASTOSAURUS Cope. Synopsis New Vertebrata, Colorado, 1873, p. 18. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 515. This genus was proposed for a lizard which presents some peculiar characters of the cervical vertebrae. There are five of these preserved in a continuous series. They are quite robust and short, resembling somewhat those of the Phrynosoma cornutum in proportions, but have remarkably small articular ball and socket as compared with that species. Another marked feature is the rib-like hypapophysis, which is equally developed on the fifth as on the second vertebra, being bounded by a fossa or groove on each side. It is probably continued, but less distinctly, on the dorsal vertebrae. The neural arch is capacious in the cervical region, and each neura- pophysis is excavated below the posterior zygapophysis, and sending a ridge downward and backward around the centrum, continuing as a low shoulder on the inferior face. Diapophysis with a single narrow capitular articula- tion, extending obliquely downward and forward; that of the third vertebra OPHIDIA. 781 smaller. Axis with an elevated neural arch, with obtuse, inferior carina. Odontoid a crescentic element, with a transvei'se groove on its anterior face. All the centra with an obtuse but prominent hypapophysial keel. Cremastosaurus carinicollis Cope. Locis citatis. Plate LX ; fig. 16. Ball of sixth cervical vertebra round. Neural arches broad, each with a low, acute keel for spine, which is elevated on the third, and produced roof-shaped backward and forward on the axis. The costal articulations are not produced below the centrum. Measurements. M. Length of cervical vcrtebrie II to VI 0. 0140 Length of axis 0038 Elevation of axis behind 0047 Diameter of odontoid (in front) 0034 Length of c. VI 0029 Diameter of ball of same 001 1 Total elevation of same 0030 Size of the "horned-toad", Phrynosoma cornutum. OPIIIDIA. Several species of snakes have been found in the beds of the White River and John Day epochs. The characters presented by the yertebrfe, the only parts as yet discovered, do not differ much from those of existing types. None of them represent species of more than the average size of the colubrine snakes now existing in the f-ame region. APHELOPHIS Cope. Synopsis of New Species of Vertebrata obt.iiued in Colorado in 1873 (Miscell. Pnb. U. S. Geol. Sarv. Terrs.), p. 16. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 518. The vertebrse of this genus have various well-marked characters which distinguish them. The neural spine is short and robust, and does not ex- tend along the entire length of the neural arch as exposed in the articulated column. There is no diapophysial process below the prezygapophysis. The zvgosphene exceeds the articular cup in width, and the posterior bor- der of the neural arch is not interrupted. There is no hypapophysis, iior 782 THE WHITE EIVEE FAUNA. hypapophysial nor any other longitudinal ridges. The costal articular surface is single and uninterrupted. These vertebrae resemble very much those of the Erycid genus Ckarina, which is found at the present time in the Pacific district of this continent. I can, in fact, detect no well-marked generic difference between them. The zygosphen of the recent species is somewhat narrower than that of the ex- tinct one. Aphelophis talpivorus Cope. Locis eitatia. Plate LX ; fig. 21. Vertebrae short and wide ; the neural spine stouter and more obtuse than in any other species here described, occupying less than half the neural arch with its basis. Zygosphene wide, depressed, with nearly straight posterior margin, not sending any ridge backward from the posterior face. Articular faces of centrum depressed oval ; ball looking upward, its axis making 45° with that of the centrum. Parapophysis not projecting below centrum. Measurements. H. Length of centrum 0.0026 Diameter of cup ^*'^'*°8^"^« ^^^ I vertical 0012 Width between parapophyses 0017 Depth of entire vertebra 0034 Width of zygosphene . 0020 Represented by three vertebrae of an individual about the size of Cal- amagras murivorus. The White River epoch of Northeastern Colorado. OGMOPHIS Cope. Neural spine of vertebra short and obtuse. No process below the pre- zygapophysis. Rib surface single, uninterrupted; rib extending posteriorly from its inferior extremity. Inferior face of centrum without hypapophysis on the dorsal region, but probably furnished with one on the cervical region. This genus resembles Aphelophis in most respects, and probably has similar general affinities. It is distinguished by the ridge which extends from the parapophysis, and the groove which is included between this and the middle line of the centrum. Two species are known to me. OPHIDIA. 783 Ogmophis oregonensis Cope. PlateLVIIIa; figs. 9-11. This snake is represented by four dorsal vertebrae and probably by a fifth from the region near the skull. The last-named vertebra has a smaller centrum than the others, as is usual with those from the anterior part of the column, but the details of its structure are much as in the others. It has an acute hypapophysial ridge which extends posteriorly into a short, sub- acute process. In the other centra, the median inferior ridge bounded by the lateral grooves, is obtuse, and has different forms. It is wide at both extremities and the surface is equally convex ; in two others it is much narrowed medially and widened posteriorly. In all of these the posterior part is slightly angulate medially. The articular faces are nearly round, and the obliquity of the ball is only moderate. The ridge from the inferior extremity of the rib surface terminates a short distance from the articular ball. The ridge connecting the zygapophyses is very prominent. The rib articular face is one-half deeper than wide; the superior half is convex, the remainder gently concave, the inferior border projecting slightly outwards. The only specimen of this species preserved rather exceeds in size the others here described, excepting the Neurodromicus dorsalis. Measurements. M. Length of centrum witb ball 0.0050 Transvetse diameter of ball 0026 Total elevation of vertebra 0060 Elevation of neural spine 0019 Width at interzgyapophj'sial ridge 0044 Vertical diameter of rib surface 0023 Width of ball of a " cervical" centrum 0020 From the John Day beds near the John Day River, Oregon. J. L. Wortman. Ogmophis angulatus Cope. Calamagraa angulatus Cope. New Vertebrata Tertiary of Colorado, 1875, p. 16. Annual Report U. S Geol. Surv. Terrs., 1873 (1874), p. 518. PlateLVIIIa; fig. 12. This species differs from the C. oregonensis in the following points. The interzygapophysial ridge is not nearly so prominent but is excavated behind the prezygapophysis. The neural spine is smaller and is not split poste- 784 THE WHITE EIVER FATOTA. riorly, as is the case with a dorsal of C. oregonensis. The hypapophysial ridge is narrower, and is subacute in a dorsal vertebra. The zygapophses are well expanded, and the zygosphen is wider than the cup. The superior and prominent portion of the rib articulation is nan'ower than the inferior flat portion. Measurements. M. Length of centrum 0.0030 Diameter of ball J t^^"^^^'^^ ^J,l ( vertical 0016 Width between parapophyses 0024 Depth of entire vertebra .0045 CALAMAGRAS Cope. Locu ciiatis, 1873, 1874. Neural spine small and obtuse ; no process below the prezygapoph- ysis, nor longitudinal ridge of the centrum posterior to the rib articular surfaces. The latter is undivided. Inferior median line with a keel, which is probably produced into a hypapophysis on the anterior part of the col- umns. This genus belongs most probably to the same natural division as OgmopJiis and Aphelophis, which when fully known may prove to be the existing family of Erycidoe. or Lichanuridce. Calamagras shares the charac- ters of the two genera named, so as to stand between them in the natural system. Calamagras murivorus Cope. New vertebrata from Colorado, 1873, p. 15. Annual Report U. S. Geol. Survey Terrs., 1873 ('74), p. 517. Calamagras truxalis Cope 1. c. Plate LVIIIa; figs. 13-15. Parts of three vertebral columns, including thirteen vertebrse, represent this serpent. The zygosphene is a little wider than the articular cup. The ball, viewed directly in the line of the axis of the centrum, has a wide, transversely placed oval outline. The balls of a set of three vertebrse in which the hypapophyses are best developed, and which I therefore supposed to belong to the anterior part of the series, are more nearly round. The ridge connecting the zygapophyses is deeply emarginate. In the anterior ver- OPHIDIA. 785 tebrse the hypapophyses are acute keels supporting an angular prominence near the center ; further posterioi-ly there is a slight prominence at the base of the ball. More posteriorly the hypapophysis forms a naiTOw but some- what obtuse ridge, terminating posteriorly in an apical angle at the inferior side of the ball. The neural arches are separated by spaces equal to the lengths of their bases. The rib articulations present the peculiarity of other members of this group, of a single surface, of which the superior half is convex, and the inferior slightly concave. Measurements. No. 1. — More anterior. M. Length of centnun 0.0027 Width of ball OOIG Depth of ball 0011 Width between parapophyses 0020 Depth of entire vertebra 0034 No. 2. — More posterior. Length of centrum 0.0030 Width of ball 0017 Depth of ball 0013 Width between parapophyses 0023 Depth of entire vertebra 0040 From the beds of the White River Epoch in Northeast Colorado. NEURODROMICUS Cope. Synopsis of new vertebrata from the Tertiary of Colorado, 1873, p. 15. Annual Report U. S. Geological Survey Terrs., 1873 (74), p. 516. Centrum small, with a prominent truncate hypapophysis. Neural arch capacious, the zygantrum wider than the articular cup. Neurapophyses bounding the canal laterally below the zygosphene; its border not angulate behind. Parapophysis projecting acutely below centi-um. An elevated neural spine. No process below the prezygapophysis. No prominent ridge connecting the zygapophyses. This genus represents a different group of snakes from those included in the three genera above described. The vertebra resembles considerably those from the anterior part of the column of one of the Crotalidce, but differs in the less robust hypapophysis and the absence of the process below the prezygapophysis. 50 o 786 THE WHITE EIVER FAUNA. Neukodromicus dorsalis Cope. Locis citatU, 1873, 1874. PlateLVIIIa; figs. 7, 8. Articular surfaces of centrum round ; the ball with a slightly upward- looking obliquity. Hypapophysis continued to cup as a prominent carina. Neural spine extending its base forward, so as to stand on the entire length of the neural arch. The rib articular process is of light form, and is sepa- rated by a considerable space from the prezygapophysis. The superior convex portion is quite small, while the inferior portion is narrow and is produced downwards. There is a trace of ridge connecting the zygapoph- yses, and a trace of a groove on each side of the anterior part of the base of the hypapophyses. Both the neural spine and the hypapophysis are thin edged, and all parts of the vertebra are delicate and light, in strong contrast to those of Calamagras and its allies. Measurements. Length of centrum 0.0045 „. ^ „ (vertical 0020 Diameter of cup, < „„„, ( transverse uu^ii Elevation of neural spine above centrum 0055 Elevation of neural spine above neural arch 0029 Length of hypapophysis below centrum 0012 Width of hypapophysis 0011 The zygantrum is capacious, and the whole neural arch open and light. The species was about the size of the black snake {Bascanium con- strictor). The White River Epoch of Northeast Colorado. MAMMALIA. The White River Epoch was very rich in Mammalia, but not more so than the preceding epochs of the Eocene proper, the Bridger and Wasatch. The composition of the fauna was very diiferent, as a number of important groups of the earlier period wei*e wanting, while several appear for the first time. Of the former kind may be included the Order Amhhjpoda, and the suborders Toeniodonta, Tillodonta, and the family of the Lophiodontidce. The Creodonta and Mesodonta are represented by a very few remnants. The MAMMALIA. 767 divisions which actually appear for the first time are few, for nearly all the characteristic divisions had very few and insignificant repi'esentatives during the Eocene. The Artiodadyla ruminantia and the carnivora are not known from the Eocene, while the Artiodadyla omnivora had very few rep- resentatives. The Menodontidce and Palceotheriidce chiefly belong to this epoch, with several families of Rodentia. The Chiroptera, probably the Marsupialia, and the rodent family of the Squirrels held over from the Eocene, while the Proboscidea had not yet appeared. No species of Mammal is common to this epoch and any of those of the Eocene, and only one or two genera of Marsupial or Marsupial-like families have continued from the one to the other, so far as present infor- mation extends. The species of the White River Epoch attained a larger average size than those of the Eocene Epochs. This is especially evident on comparison of related or corresponding types of the two periods. The Ambhjpoda, which embraces the largest Mammalia of the Eocene, became extinct. The most notable increase of size is seen in the Perissodadyla, where the succes- sion is most continuous. The same is generally true of the flesh-eating series. The number of individual mammals of this epoch in Middle North America was evidently very great. Many of the species were represented by great droves, and their bones form beds of considerable extent. A locality in Colorado, examined by the writer, embraced about forty acres of naked, soft calcareous rock, carved by erosive action into areas of various sizes. Here the surface of the rock was found to be covered with the remains of the smaller and some of the larger species of the fauna. There were innumerable rodents, and small Artiodadyla and Carnivora; numerous Marsupialia, Creodonta, and Poebrotherium. There was a great abundance of Hyracodon, and several other rhinoceroses, with quantities of three-toed horses. No traces of the huge Menodontidce were there, but at a locality some miles distant, a similar deposit of these large animals was found, mingled with rhinoceroses. Evidently the causes which overwhelmed the smallei- forms did not aff"ect the giants, which only yielded to some other and more irresistible influence. 788 THE WHITE EIVER FAUNA. MARSUPIALIA. Cuvier demonstrated the existence of species of this order in the gypsum of the upper Eocene of Paris, and additional species have been made known by Aymard, Filhol, and others. In 1873 I discovered in Colorado a number of species which agree very closely with the French forms, so far as can be ascertained from the dentition. These I referred to the Insectivora,^ but subsequently identified^ them as Marsupialia. They are nearly related to the European forms, and whether they can be placed in a distinct genus remains to be ascertained. A species of the same group, if not the same genus, is described in Part I of this volume, from the Wind Eiver Eocene (page 269). Along with these species were found several others, less evidently members of the Marsupial order. I refer to the genera Mesodectes, Domnina, and Menotherium. Close allies of the first of these had already been refen-ed by Leidy to the Insedivora. I have in the first part of this book placed the group in the suborder Creodonfa and the family of Lcptididce, but with a feeling of uncertainty whether the family may be Marsupial or not. Dom- nina is, I suspect, chiropterous Menotherium resembles the Leptictidce, but still more the Ifesodonta, where I originally placed it. I leave it there for the present in the immediate neighborhood of the genus ApheUscus. For purposes of determination from dental characters I compare these genera in a table, as follows. Some of them have been already defined in the ana- lytical table of the genera of Creodonta, page 269. I. Fourth inferior premolar constructed on the type of the true molars, with three an- terior cusps. Mental foramen anterior, below fourth premolar; inferior true molars subequal. Peratherium. Mental foramen below first true molar; inferior molars diminishing in size posteriorly, Domni7ia. II. Fourth i^remolar with three anterior cusps, as in I; but unlike true molars; True inferior molars with only two cusps in front Mesodectes. III. Fourth premolar simple; unlike true molars; True inferior molars with two anterior tubercles Menotherium. 'Anuual Report U. S. Geol. Surv. Terrs., 1873 (74), p. 465. »3ulletiu U. S. Geol. Surv. Terrs., 1879, p. 45. MAESUPIALIA. 789 There are five species of Peratherium known to me, two of Domnina, and possibly of Mesodectes, and one of Menotheriwn. FlO. 32. — Skull of opossum {Didelphya rriginiana), uatural size, posterior view, parts of the right mastoid and squamosal boues removed. M, mastoid foramen; SBS, subsquamosal ; PG, postglenoid; PZ, postzygomatlc foramen. PERATHERIUM Aymard. Merpetotherium Cope. Paleontological Bulletin, No. 16, August, 1873, p. 1. Synopsis of New Vertebrata from the Tertiary of Colorado (Misc. Pub. U. . Geol. Surv. Terrs.), October, 1873, p. 4. Annual Report U. S. Geol. Surv. Terrs., F. V. Hayden in charge, 1873 (1674), p. 465. 113 4 Dental formula: I. -; C. ^-j Pm. -; M. -. The superior canines are well 4 13 4 developed. The premolars are compressed, with one apex, no inner lobes, and two roots. The superior molars, excepting the last, present two median Vs, which would be termed external but for the fact that the external basal cingulum is so developed as to constitute an external crest. A single internal lobe, which is less elevated than the median. The last molar has but one median and one internal V. The superior incisors are unknown. The in- ferior incisors are subequal and closely placed; the first three ai-e parallel, Inferior canine well developed, recurved. Inferior premolars compressed, simple unicuspid. Molars consisting of two Vs, with apices external. The inner extremity of each branch of the anterior V is a pointed cusp, behind which stands, on the inner edge of the crown, a third cusp opposite to the middle of the posterior V. The last inferior molar is little shorter than the others, but the second V is nan-owed so as to be only a heel. The molars do not materially enlarge anteriorly, and the posterior mental foramen is not posterior to the first true molar. 790 THE WHITE RIVER FAUNA. The general osteology of this genus is unknown, as the only portions of the skeleton yet discovered are mandibular rami and the cranium anterior to the middle of the orbits. From these it appears that the cranial sutures are distinct at maturity, and that the nasal bones are elongate and well developed Either the maxillary bounds the orbit in front or there is a large lachrymal bone. A pit on the anterior rim of the orbit is probably the lachrymal canal. The foramen infraorhitale is well anterior to the orbit. The symphysis mandibuli is loose. In determining the affinities of this and other questionable genera of this epoch it is first necessarj^ to ascertain the homologies of the cusps of the molar teeth. The opossums are characterized by the presence of three longitudinal series of tubercles on the superior molars. The homologies of these cusps are rendered clear by the character presented by the fourth superior premolar, where the anterior intermediate cusp is wanting. The external cusps are really such, and are not developed from a cingulum external to the true external cusps, as appears at first sight to be the case with such animals as the Talpidce. The intermediate cusps are really such, although the posterior looks like the apex of a V-shaped external cusp. In Perathe- rium the external cusps are smaller than in Didelpliys, and the intermediate Vs so much better developed, that the type is much like that of the Talpidce, in whose neighborhood I originally referred it. This leads to a consideration of the question of the homologies of the cusps in the genera of the old order of Insectivora proper, and of the Creo- donta. Mr. St. George Mivart has briefly discussed the question so far as relates to the former group.'' He commences with the primitive quadri- tuberculate type presented by Gynmura and Erinaceus, and believes that the external cusps occupy a successivel}'^ more and more internal position, till they come to be represented by the apices of well-developed Vs, as in the ungulate tj'pes. The Vs are well developed in several families, and in Chrysochloris the two Vs are supposed to be united and to constitute almost the entire apex of the crown, while in Centetes the same kind of a V forms a still larger part of the crown. I believe that tliese conclusions must be modified, in the light of the characters of various extinct genera, and of the genus Didelpliys. In the 'Journal of Anatomy and Physiology, II, 138 figures. MAESUPIALIA. 791 first place, there is an inherent improbability in the snpposition that the external Vs of the superior molars of the Insedivora have had the same origin as those of the Ungulata. Tlie movements of the jaws in the two groups are different, the one being vertical, the other partially lateral. In the one, acute apices are demanded; in the other, grinding faces and edges. We have corresponding Vs in the inferior dental series, and we regard those as produced by the connection of alternating cusps by oblique ridges. In homologizing the superior cusps, we have, as elements, two external, two intermediate, and two internal cusps. The first are opposite the external roots, and the anterior internal is opposite the internal root. First, as regards Centetes and ChrysocMoris. Besides the strained char- acter of the hypothesis that supposes the V-shaped summit of the crown to represent two V-s fused together, there is good evidence obtainable in sup- port of the belief that the triangle in question is the usual one presented by the Creodonta. This clearly consists of the two external and the anterior internal cusps united by angular ridges. The form is quite the same as in Leptictis and IctojJS^ (Plate XXIX a, fig. 3), and nearly that of Deltatherium (Plate XXIII d, fig. 8 a), where the external cusps are present. Centetes and ChrysocMoris only differ from these in that the external cusps are wanting. In addition, the latter genus presents a rudiment of the posterior inner tubercle, as is seen in Deltatherium (Plate XXV a, fig. 10). An ex- planation similar to this is admitted by Mr. Mivart to apply to the cusps of the inferior molar of Centetes. It remains to ascertain whether the apex of the V in ChrysocMoris represents the internal or intermediate cusp. Secondly, as regards the Talpidce and Soricidce, where the external Vs are well marked. If we examine the external cusps in the genus Didel- phys, we find that the posterior one becomes gradually more anterior in its position, until on the second true molar it stands largely above the inter- space between the roots, instead of over the posterior root. It will also be seen that the anterior intermediate tubercle is distinct and of insignificant proportions, while the posterior intermediate is large and is related to the posterior external, as is the apex of a V to its anterior base. In this ar- rangement I conceive that we have an explanation of the Vs of the Talpidce ' Leidj's Extinct Faiina of Dakota and Nebraska, 351, PI. XXVI, fig. 29. 792 THE MIOCENE FAUNA. and Soricidce. The first true molar of Scalops is a good deal like that of Bidelphys, but the anterior cusp is larger, and tliere is no anterior interme- diate cusp, while the posterior external is of reduced size. The posterior V is better developed than in Bidelphys, but is composed in the same way, of a posterior intermediate cusp, and a posterior external with a posterior heel. These are united by stronger ridges in Scalops, Condylura, and Blarina than in Didelphys. On the second true molar in Scalops a V represents the an- terior external cusps of the first true molar. Whether this V has a consti- tution like the posterior one, i. e., is composed of external and intermediate cusps joined, is difficult to determine; but it is probably so constituted. It seems to be pretty clearly the case in Blarina, where the fourth premolar and first true molars may be compared, with a resulting demonstration of the correctness of this view. In Condylura the Vs have become more de- veloped and the external cusps reduced, so that the analysis is more difficult. This interpretation applied to Urotrichiis and Galeopithecus gives them quadrituberculate molars, not trituberculate, as determined by Mivart. Mystoniys is trituberculate. The intermediate tubercles are present, but are imperfectly connected with the external, so that Vs are not developed (vide figures of Mivart and Allman). This genus ofi'ers as much confirma- tion of the homology here proposed as do the opossums, but it difi"ers from the latter in having the anterior intermediate tubercle the larger, instead of the posterior. Mystomys and Solenodon also confirm the determination the internal angle of the crown in Centetes^ is the anterior internal cusp. In conclusion I give the following synoptic view of the constitution of the superior molar teeth in various genera of the Bunotheria: External cusp. External cusp. ExterBal cusp. External cusp. Noexternal cusp. Noexternal cusp. Intermediate. No intermediate. Intermediate. No intermediate. No intermediate. No intermediate. Two internal. Two internal. One internal. One internal. Two internal. One internal. AdapidiE. | Gynjnura. Mystomyidse. Mesonyx. Chrysochloris Centetes. Tupjeidie. Ennaceus. Mioclffinus. Leptictis. (second inter- Galeopitheeida) Macroscelididas. Miacis. Ictops. nal rudimen- SoricidiB (with Talpidae. Stypolophus. tal). Urotrichus). (Didelphys.) Oxvaena. Solenodon (sec- (C.anis.) Cliriacus. Deltatherium. Esthonyx (pos- teriorinternal rudimental). ond internal rudimental). 'This view was first advanced by the writer in the Annual Report of the United States Geo- logical Survey Territories, 1873 (1874), p. 472. MARSUPIALIA. 793 In criticism of the above table, it may be added that the external cusps stand within the border in Stypoloplms and DidelpJiodus, and are nearly con- fluent in the false sectorials of Oxycena and Pterodon. One is smaller than the other in Mesonyx. In Solenodon they are rudimental. From the above considerations it appears that the external, often minute, cusps of the teeth of Insectivora are the homologues of those of true exter- nal series, and do not represent an additional cingulum. Comparisons of the molars of the extinct and recent forms are thus facilitated. Peratherium is nearly allied to Didelphys, but has not the inflected angle of the mandible of that genus. The difference in dentition as above pointed out consists in the elevation of the median cusps of the superior true molars into Vs, and the obsolescence of the tubercles of the external series. It is quite possible that these characters may not be sustained in a comparison of the numerous extinct and recent species. The name Peratherium was proposed by Aymard for some similar species from France, but his charac- ters were derived from the inferior dentition, and were of no great impor- tance, as remarked by Filhol. Thus he states that the third inferior premolar is larger in the extinct than in the recent species, a character not generic, and which, as Filhol shows, is not common to all the French species, and -which is not found in those of America. Animals of this genus were abundant in North America during the White River epoch of the Miocene, but I have not seen any of their bones from later deposits. Those obtained by me in Colorado represent six spe- cies, some of which,J have on former occasions referred to another genus (Embassis). Future discovery may justify this course, but at present I suppress the name.^ 'In my account of the genus Herpetotherium, published in the Annual Eeport of the Hayden Sur- vey for 1873 (p. 465), it is stated that this genus has a greater number of molar teeth than in Talpa, "thus — in the extinct to ~ in the recent genus." As these figures are absurdly erroneous, it becomes necessary to explain that the numbers originally given were ^-^ and ?^- The paper was printed during my absence from the East, and the editor, not understanding my meaning, allowed them to go to press in the erroneous form in which they stand. 794 THE WHITE EIVER FAUNA. The species are distinguished as follows : I. Anterior triangle of inferior molars with the two inner cusps subequal and deeply separated. a. The anterior triangle not much more elevated than the posterior. Larger ; last two molars 4.5™"° long ; ramus 4°"° deep at middle P. fugax. Smaller; last two molars 4.5"'"; ramus 3""° P. tricuspid. Smallest ; last two molars 2.7"" ; ramus 2"" P. huntii. aa. The anterior triangle twice as much or more elevated than the posterior. Larger ; last two molars 4.5°"" P. scalare. II. The anterior cusp of the elevated anterior triangle insignificant, the posterior inner cusp much larger. A groove extending to the base of the anterior cusp on the inner side ; heels of molars supporting two cones P- inarginale. No groove separating anterior cusps; heels of molars very low P. alternans. Peratherium fugax Cope. Herpetotherium fugax Cope. Paleontologic.al Bulletin No. 15, August, 1873, p. 1. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 467. Plate LXII; figs. 1-9. This species is represented by the anterior half of the cranium with mandibular rami, with nearly complete dentition, of one individual ; and by larger and smaller parts of mandibles of fourteen others. The portion of cranium preserved is somewhat crushed by pressure, but it was evidently wider in proportion to its length at the frontal region than in the existing Didelphidce of America. The muzzle is broken away, but the inferior incisor teeth show that it was not elongate. The skull begins to expand in front of the foramen infraorUtale, and at the lachrymal region overhangs, by a little, the maxillary border. The orbits do not appear to have been large. The malar bone, if it existed, is lost from the specimen. The nasal bones are narrowed by the elevated maxillaries for the distal two thirds of their length. They then rather abruptly expand to double the width, and terminate in a wide slightly convex posterior border. Either the maxillo- premaxillary suture is situated well in advance of the canine tooth, or else it has become obliterated by coossification. The foramen infraorbitale exterius is above the third premolar tooth. The superior canine is compressed, but neither the anterior nor posterior edges are acute. The first premolar is smaller than the others, and its crown is rather obtuse. It is separated by a short interspace from the second. The latter has a trace of a posterior basal tubercle ; its edges are not acute. MARSUPIALIA. 795 The third premolar is most prominent ; its posterior edge is generally worn so as to be acute. There are no external cingula on the premolars. The elevation of the external cingula of the true molars is such as to produce, on wearing with the middle cusps, two triangular areas, of which the an- terior is a little smaller than the posterior. The inner lobe of these teeth is more nearly opposite the anterior than the posterior triangle, giving a straight anterior and oblique posterior outline to the crown. There is no posterior basal cingulum on the true molars. The inner lobe of the fourth true molar is compressed and acute, and sends a sharp edge to the base of the small cusp which represents the posterior external triangle of this tooth. The fourth inferior incisor is not larger than the others, and is directed a little more upwards than they. The inferior canine is large, but smaller than the superior, though similar in form. There is no interspace between the canine and first inferior premolar; but a short one between the first and second premolars, and a shorter one between the second and third premolars. The crowns of these teeth are a simple cusp, which is mainly over the anterior root. In all the true molars the anterior triangle is not much more elevated than the posterior, and the anterior and posterior cusps of the inner side of the former are well separated from the external cusp, which much exceeds them in size. The anterior triangle of the first true molar is a little narrowed. The cusp of the internal side of the posterior triangle is about as high as the anterior cusp. In many specimens there is a small cusp be- hind this one ; in some specimens it is very small, while in others it is wanting. This peculiarity I at one time thought characteristic of another species, the P. tricuspis. This I do not now believe to be the case, but find that that species possesses other and more reliable characters. The heel of the last inferior molar of the P. fugax is somewhat narrowed, and always presents thi-ee cusps. There ai-e two mental foramina — one, the larger, below the first pre- molar; the other below the fourth molar, counting from either end of the series. Measurements. M. Leugth of superior molar series plus the superior canine 013 Length of premolar series 0052 Length of molar series 0063 796 THE WHITE RIVEE FAUNA. M. Liength of second true molar - 0016 Width of second true molar 0020 Length of inferior molar series of a second iudivldnal 0128 Depth of ramus at first premolar 0016 Depth of ramus at first true molar 0035 Depth of ramus at last true molar 0030 These measurements indicate an animal of about the size of the com- mon mole of this country {Scalops aquatious). The teeth are relatively smaller, and the mandibular rami deeper and less robust. Peratherium tricuspis Cope. Merpetotieriavi trimtspis Cope. Synopsis of New Vertebrata from the Tertiary of Colorado (Miscell. pub. U. S. Geol. Survey Terrs.), October, 1873, p. 5. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 466; partim. PKiteLXII; figs. 10-11. This species as at present defined rests on a fragment of a lower jaw, which supports the second and third true molars. These teeth are similar to those of the Peratherium tricuspis, and possess, like some individuals of that species, a prominent posterior inner cusp of the posterior triangle. The character which distinguishes it from the typical species is the shal- lowness of the mandibular ramus. The depth of this bone is not over half that of some of the specimens of P. fuyax, with teeth of equal size, and two-thirds the measurement of some others. This character is expressed in the following — Measurements. m. Length of second and third true molars 0040 Width of third true molar 0010 Depth of ramus at second true molar 002.5 From the same locality as the H. fugax. ^ Peratherium huntii Cope. Plate LXII; figs. 12-16. Merpetotherium huntii Cope. Synopsis of New Vertebrata, Colorado, October, 1873, p. 5. Annual Kept. U. S. Geol. Surv. Terrs., 1873 (1874), p. 466. H. sterensoiiii Cope, Synopsis Vert., Colorado, p. 6. Ann. Report U. S. G. S., 1873 (1874), p. 467. Miothen gracile, Synopsis Vert., Col., 1873, p. 8. Domnina gracilis Cope, Ann. Report U. S. G. S., 1873 (1874), p. 470. This is the smallest species of the genus known, and is readily distin- guished from the P. fugax b}^ other characters than its minute size. These are the uninterrupted series of premolars, which are without interspaces, and the greater acuteness and elevation of the cusp on the inner side of the posterior triangle. MARSUPIALIA. 797 The mental foramina are, as in P. fugax, below the first and fourtk molars. The last inferior molar is as long or nearly as long as the penulti- mate, but has a rather narrower heel, always with three small cusps. The external anterior cusp is always much larger than the two internal, whicli are well apart, and not much elevated. In some specimens, as in P. fugax, there is a distinct third cusp on the posterior triangle, on its posterior inner border, but it is sometimes obsolete, and sometimes wanting. Hence the species, P. stevensonii, founded on this peculiarity, must be suppressed. Measurements. -^ Length of deutal series, omitting canine and Pm. 1 (No. 1) 0072 Length of first true molar 0013 Elevation of first true molar 0010 Length of third true molar 0013 Depth of ramus at third true molar 0019 Length of last two molars 0029 Length of third true molar 0015 Elevation of third true molar 0012 Depth of ramus at third true molar 0020 I have portions of seven mandibular rami of this species, which were found at the same locality as the preceding species. It is dedicated to my friend Professor T. Sterry Hunt. Peratherium scalare Cope. Herpeiotherium scalare Cope. Synopsis New Vertebrata from Colorado, 1874, p. 7. Ann. Report U. S. G. Survey Terrs., 1873 (1874), p. 467. Plate LXII ; figs. 17-18. This species is represented by portions of the mandibular rami of twa individuals of the size of those of the P. fugax. These only support some of the posterior molar teeth. The species is readily distinguished by the increased disparity in the elevations of the anterior and posterior portions of the molar teeth, resem- bling in this respect the Peratherium alternans. It is a considerably larger species than the latter, and exhibits a distinct anterior cusp, of moderate elevation, which is separated from the median external by a deep notch. It is entirely on the inner side, and sends a cingulum to the external base of the outer median. Fourth molar largest; heel narrowed, with three tubercles. The masseteric fossa is well defined, and is bounded antei'iorly by the strong external ridge of the base of the coronoid process. This ridge i& 798 THE WHITE ElVER FAUNA. stronger, and the fossa extends further forwards than in any of the various specimens of P. fugax which display this region. There is no internal pterygoid fossa as in P. alternans. Measurements. Length of last three molars .•'. 0660 Length of second true molar 0020 Elevation of second true molar 0022 From the same locality and horizon as the preceding species. Peratheeium marginale Cope. Berpetotherium marginale Cope. Synopsis New Vertebrata, Colorado, 1873, p. 6. EmbassU marginalit Cope, Ann. Report U. S. G. S. Terrs., 1873 (1874), p. 468. Plate LXII, figs. 19-21. This species has a more slender mandibular ramus than the P. fugax, but teeth of the same size, thus having the proportions of the P. tricuspis. The anterior triangle is more elevated than the posterior, and is not fissured on the inner side so as to distinguish the anterior and middle cusps, except at an elevated point. From the fissure between them a shallow groove descends inwards on the front of the tooth. The inner principal cusp is thus as large as the outer, and the triangle is transverse, or much broader than long. The species is also peculiar in the constitution of the posterior triangle or heel, which supports two elevated acute cones, which are some- times curved forwards. The middle of the heel is concave. I at one time thought that the P. marginale was, with the P. alternans, worthy of generic separation, but so many intermediate conditions connect this form with that seen in P. fugax, that I no longer maintain this opinion. There are four molars in the typical specimen, a part of the first being broken away. The last true molar is I'ather smaller than the others, and relatively smaller than in P. fugax, and is not narrowed posteriorly, sup- porting two opposite well-developed cusps instead of the thi-ee weak ones of the other species. It is crowded close to the base of the coronoid process, instead of standing well in front of it as in P. huntii and P. fugax, which gives the appearance of not being fully protruded, although its cusps have the same elevation as those of the other molars. The inferior border of the ramus rises strongly at this point, much more so than in the two species named, showing that the crowding of the fourth molar is not due to imma- MAESUPIALIA. 799 turity. It is broken off at the middle of the first molar, and does not display any mental foramen up to that point. A cingulum descends from the anterior and posterior cusps to the base of the median on the outer side This species is about the size of Domnina gradata, and resembles it in the larger anterior teeth. Measurements, M. Length of last three molars 0052 Length of third true molar 0024 Elevation of third true molar 0018 Depth of ramus at third true molar 0023 Two other fragments of mandibular rami support teeth which have much the character of those of the present species as regards the form and proportions of the anterior triangle. The posterior triangle, however, is like that of some of the other species, with two low and little-developed cusps. One of the specimens includes the anterior base of the coronoid process, which does not rise abruptly as in the type. These specimens cannot be referred t© the P. marginale, and they differ from the P. alternans in the anterior groove between the inner cusps of the anterior triangle. Peratherium alternans Cope. Embasm alternans Cope. Synopsis New Vertehrata Colorado, 1873, p. 4. Annual Report U. S. (Jeol. Surv. Terrs., 1873 (1G74), p. 468. Plate LXII, ligs. 22-24. Our knowledge of this marsupial rests on the posterior part of the right mandibular ramus supporting the last two molars of a single individual. All these parts present characters at variance with the species already de- scribed. The anterior triangle is much elevated above the heel, and appears at first sight to have but two cusps. The heel is low and concave, and has two low cusps, neither of which is crescentic. On these accounts I formerly referred this species to a genus distinct from the P. fugax, which I called Emhassis. I believe, however, that the anterior cusp of the molars exists, although in a rudimental condition, and that present evidence does not warrant generic separation. The last molar is distinctly smaller than the penultimate, and its heel is not narrowed, as in the typical species of this genus, but is truncate and supports two cusps. There is a cingulum on the outer side of the anterior triangle of both molars. The ridges at the base of the coronoid process are 800 THE WHITE RIVER FAUNA. stronger than in any other species. The masseteric fossa is deep, and is bounded in front by a prominent ridge which forms the external base of the coronoid process. The direction of this crest is nearly vertical, and its prominence throws the teeth to the inner side of the ramus. There is ^, strong horizontal ridge on the inner side of the base of the coronoid process, in line with the alveolar border, which rises posteriorly and incloses a shallow fossa with the prominent internal vertical edge of the base of the coronoid process. The last molar is situated more than half its length in front of the base of the coronoid process. The teeth of this species are about the size of those of P. fugax. The depth of the mandibular ramus is unknown, as its inferior border is broken away. The P. alternans differs from all the species above described in the strong ridges of the coronoid region above described. Measurements. M. Length of two last molars 0038 Width of third molar 0020 Elevation of third molar 0018 From the same locality and horizon as the other species of the genus. BUNOTHERIA. CREODONTA. I refer provisionally to this order and suborder a few species which existed during the White River Epoch in North America. Two species of about the size of the Hedgehog were discovered in the bad lands of Southern Dakota by Dr. Hayden, and were described by Dr. Leidy as Leptidis haydeni and Idops dakotensis in 1868.^ A third species of about the same size, the Mesodectes caniculus, was discovered and described by myself in 1873, with several smaller species already refei'red to the genera Peratherium and Domnina. The three genera first named belong to a distinct division from those of the two genera last named, which is, perhaps, of ordinal value. But this remains uncertain on account of the incompleteness of the speci- mens on which they repose. The entire cranium, without mandible, of Leptidis haydeni is known, and part of the cranium with mandible, and part of the skeleton, of Mesodedes caniculus are in my possession. 'Extinct Mamm. Dakota and Nebraska, 1869, pp. 345-361. BUNOTHERIA. 801 MESODECTES Cope. (Expl. Survs. W. of lOOtli Mer., Lt. G. M. Wheeler); April, 1875. Syst. Catal. Vert. Eocene, New Mexico, p. 30. laacis Cope, Paleontological Bulletin (August, 1873) No. 16, p. 3. Bulletin U. S. Geol. Surv. Terrs., No. 1, 1874, p. 23. Ann. Kept. U. S. Geol. Surv., 1873 (1874), p. 470 ■ (nom. prieocc). This genus embraces at present but a single species, which is known from numerous specimens discovered by the writer in the White River Miocene formation of Colorado. From these it appears that Mesodectes is closely allied to the Leptidis and Idops of Leidy, occupying a position between these in the system. In Leptidis the last premolar is sectorial in form, consisting of a single compressed longitudinal crest, without internal tuberosity or cusp. In Idops the last premolar exhibits a structure similar to that of the first ti-ue molar, viz, two exterior cusps and well-developed third on tlieir inner side, thus giving a horizontal section of the tooth a sub- triangular foi*m. In Mesodedes the last premolar possesses a single acute cusp, as in Leptidis, with an internal cusp or heel homologous with that in Idops. Such peculiarities are necessarily regarded as tangible definitions of generic groups, and are such in this case, although they separate species which have considerable resemblance in some other respects as far as known. The molars of the superior series have two exterior compressed conic cusps and a stout subtriangular internal one. Behind the latter is a strong cingulum, supporting a rudimental cusp behind and within the principal one. Inferiorly there are three tubercular molars, of which the two anterior are composed of two elevated cross-crests, which form partial V's, opening to the inner side. The last premolar is larger than the true molars, and supports three anterior conic tubercles, the inner and outer equal, and a heel with a conic tubercle on the outer side. The number and character of the teeth in front of this one are unknown. The posterior part of the cranium exhibits characters similar to those of Leptidis, but in the specimen the superior walls are wanting. The animal is not adult. The exoccipitals are distinct from the supraoccipital, displaying a wide, smooth sutural face. The mastoid is quite distinct, and is narrowed. Its superior portion enters into the posterior face of the skull, the union being formed by the posterior border of the squamosal. There are neither paroccipital nor mastoid processes, and the inferior extremity of the mas- 51 c 802 THE WHITE EIVER FAUNA. toid is grooved inwards and forwards to the inferior side of the skull. The meatus auditorius is wide, and has no infeiior wall. There is an extensive petrous fossa inclosed between the exoccipital behind, the basisphenoid and basioccipital within, the alisphenoid in front, and the squamosal and mas- toid externally. This is not overroofed on the inner side by a prolongation of the lateral border of the basisphenoid, as in JErinaceus. In the middle of the fossa is situated the petrous bone, which extends from the mastoid in- wards and forwards to the adjacent parts of the basioccipital and basisphe- noid. There is a well-marked postglenoid process, which is divided into two parts by a deep notch. The inner portion is directed obUquely some- what forwards. Just inside of it a crest, probably the inferior border of the pterygoid process of the sphenoid, extends inwards and forwards, joining the longitudinal pterygoid. The latter terminates at the inner border of the large fossa above described. The squamosal bone has a remarkable exten- sion behind the postglenoid process, and then rises into the oblique crest which forms the boundary of the inion. Longitudinal crests connect this with the superior extension of the postglenoid process, inclosing a fossa with a subsquamosal foramen, a postglenoid foramen between them. In this re- gion this genus is identical with Leptictis, and resembles Solenodon more than any other living form. In that genus the mastoid is not larger, but is on the lateral instead of the posterior face of the skull. The inferior part of the squamosal in Mystomys also resembles considerably that of Mesodectes, but the mastoid is far larger, and the otic region is roofed by the basisphe- noid wings. The squamosal is much shortened behind in JErinaceus, and there is no postglenoid process. The basioccipital and basisphenoid are continuous, as in Solenodon. The subsquamosal foramen is especially char- acteristic of the Didelphidce. The cervical vertebrce are short and transverse, and have well-developed lateral arterial foramina and diapophyses. The centra are depressed to a considerable degree, and are without hypapophyses. The neural arches are narrow, and without spines. The atlas is expanded, and has a very short diapophysis. The axis has a solid processus odontoideus. The dorsal verte- brae are smaller than the cervical in transverse diameter of the centrum, which somewhat exceeds the length ; the articular faces are nearly plane. BUNOTHBRIA. 803 The intervertebral foramina are quite large, and the narrow neurapophyses are almost entirely occupied by the bases of the diapophyses. These are well developed, obliquely tnincate below at the end, and grooved on the under side of the shaft. The neural spines are elevated, narrow, and acute in front. The ribs are flat, and the capitular and articular faces are well developed. The prcesternum is shaped somewhat like the sternum of a bird. It has a prominent inferior longitudinal keel, which disappears posteriorly, leaving a vertically-oval face of articulation for the second sternal segment. The superior face is slightly concave, and the only lateral articular faces are those for the attachment of (?) first ribs, and are of considerable size, and are adjacent to the anterior extremity. The borders of the bone are but little contracted behind them. The scapula is elongate, and has an elevated crest, descending abruptly near the glenoid ca\'ity. The latter is an elon- gate oval, the border at one end more produced than at the other, and ter- minating in a short hooked coracoid. The humerus has a protuberant head and shaft, and condyles much flattened. The head is nearly 180° in arc, is posteriorly directed, and of compressed form. On the inner side is a depressed tuberosity for the pec- toralis muscle, while opposite to it the greater tuberosity rises as high as the head, parallel to it. Distally, the condyles are continuous, nearly con- cave, and supplemented by huge inner and a smaller outer epicondyles. There is no supracondyloid foramen, but a strong arterial foramen. The cast of almost the entire brain is preserved, and, as the parietal bones are wanting, the proportions are clearly traceable. The olfactory lobes are broken off. The superior face of the hemispheres and cerebellum together have a subquadrate outline, a little wider than long. The cere- bellum is completely exposed behind the hemispheres, and is strongly angu- late at its upper posterior border to fit the inion. The vermis is nearly as wide as each lateral lobe. The surface of the hemispheres is smooth, and the sylvian fissure distinctly indicated. As compared with other forms, the following points may be observed: In Chrysochloris and Centefes, as above noted, the external cusps of the superior molars are wanting. In the genera in which they are present, as 804 THE WHITE RIVER PAUFA. Tupaia, Talpa, Sorex, &c., there are two of the middle series, as in Pera- therium, and these add a strong internal lobe also. In Erinaceus and Gym- mora they are quadrituberculate. The closest approximation is made by the g-enera Mystomys and Solenodon, the former African, the latter West Indian. In these the external cusps are present; there is but one well- developed median, and in the latter the internal is quite reduced. The molars of Mesodedes thus resemble most closely those of Solenodon (Brandt), but the external cusps are more developed than in that genus. Among the Eocene genera, the greatest resemblance is to be seen in the genvis Delta- therium. The internal cusp of Mesodedes is connected with the external ones by oblique ridges, as in Delthatheriwn ; and on one of these is a rudi- mental tubercle, representing an intermediate cusp. The dentition of the lower jaw is quite different in Deltatherium in the simple last premolar, and cutting last true molar. In the lower series the form of the true molars is not unlike that of several diverse recent genera. It is quite unique in its large four or five cusped last premolar, which has some resemblance to a modified sectorial. The nearest approach to it which I can discover among recent genera is the Madagascar Galeopithecus. In respect to the remainder of the skeleton, numerous characters dis tinguish it from the Centetidce (which includes Solenodon) and the Mysto- myidce. Both of these lack the zygoma, which is present in Septididce, and have the nasals coossified, while they are distinct in these tertiary forms ; Mystomys, further, lacks the clavicle. The pi'esence of the zygoma without postorbital processes is a point of resemblance to Erinaceus, but the strongly keeled presternum and absence of cervical neural spines are found elsewhere in the Talpidce. In the presence of the humeral arterial foramen, it again differs from Erinaceus and resembles other forms of the order. Comparisons with the Marsupialia are chiefly to the DidelpMdce. The superior molars are much like those of Didelphys, the inner cusp of the third premolar being a point of difference not seen, however, in the allied Leptidis. The latter, according to Leidy, has only two superior incisors on each side, a wide divergence from the opossums. In the inferior molars the absence of the anterior inner cusp is a strong mark of distinction. The BUNOTHERIA. 805 presence of the eubsquamosal foramen is on the other hand a marsupial character. The absence of any but rudimental neural spines of the cervical vertebrae is again an important difference from Bidelphys. The evidence is in favor of the Leptictidce, as represented by 3Iesodectes, being a group of Biinotheria, and a member of the Creodonta, as defined by the form of the superior molar teeth. Mesodectes canicdlus Cope. Imcis canicidiis. Paleontological Bulletin No. 16, p. 3. Anu. Report U. S. Geol. Survey Terrs., 1373 (1874), p. 473. Plate LXII; figs. 33-50. This species is represented by portions of the skeletons of six individ- uals. All of these lack the anterior teeth of both jaws, while one includes mandibular teeth with vertebrae, ribs, humerus, scapula, presternum, a large part of the cranium, &c. The basioccipital and sphenoid have straight lateral borders which are slightly decurved into a low ridge on each side. A low median ridge includes with these two a pair of longitudinal shallow fossae, which fade out on the sphenoid bone. The occipital condyles are divergent, and with very small laterally -looking portion. The foramen magnum is largely trans- verse. The exoccipital does not extend far forwards, and the mastoid has a very short anteroposterior extent. A foramen issues from the base of the fossa inclosed by the longitudinal crests of the posterior part of the squa- mosal bone, and there are two other foramina above the superior of these crests. A small foramen pierces the same bone behind the inner extremity of the external half of the postglenoid jirocess A groove follows the free posterior edge of the squamosal, separating it from the mastoid. The petrous is somewhat rectangular in its sections, and its transverse diameter exceeds its anteroposterior. The inferior face is horizontal in the outer half, and looks forwards and inwards on its inner half. The first rib is little compressed, and becomes very robust towards and at the distal extremity, where it is truncate for articulation with the praester- num. The extremity is oval in section. The shaft of the humerus is somewhat curved, and the anterior com- 806 THE WHITE RIVER FAUNA. pressed crest does not project abruptly, but exhibits a muscular insertion some distance below the head. The edges of the outer lobes of the first superior molar are acute ; there is no external cingulum, but the diagonal crest from the median cusp passes to the posterior base of the posterior outer. There is a short but strong cingulum on the posterior base of the median lobe, which terminates in a small internal cusp. The rudimental anterior middle cusp is on the anterior diag- onal ridge, which does not reach the base of the outer anterior cusp. The outer cusp of the last premolar is elongate and compressed ; the inner cusp is small, acute, and opposite the posterior margin of the outer; enamel smooth. The anterior of the two prisms composing the inferior true molars is more elevated than the posterior. The crests of each form a V with the obtuse apex outward, and the anterior limb is shorter than the posterior. The last molar is a little smaller, and is produced behind by the addition of a small median lobe. In the last premolar, the conic cusps are well sepa- rated, and the inner one of the heel is insignificant. This tooth appears to have been the last one protruded; its temporary predecessor is distinguished by the obtuseness of the cusps, especially of the anterior one. Mandibular ramus deep, compressed, without inferior hook as far as opposite the basis of the coronoid process. Measurements. M. Lengtli of sectorial and two tuberculars 0.0210 Length of sectorial alone - 0045 Width of sectorial 0020 Width of first tubercular 0030 Length of first tubercular 0032 Depth of jaw at first tubercular - 0060 Width of skull behind 026 Length from occipital condyle to postglenoid process 013 Length of basioccipital 006 Width of basioccipital medially 005 Transverse extent of postglenoid process 006 Length of two centra, third and fourth cervical vertebrae 007 Transverse extent of fourth cervical between parapophyses 012 „. ^ c i V, V J < transverse 006 Diameter of centrum behind ^ < vertical 003 Total elevation fourth cervical 0066 Total length of axis 007 Length of odontoid process 0025 ^ ^, ^ . , < vertical 0090 Diameter of atlas anteriorly < . ( transverse 0140 BUNOTHERIA. 807 M. Total transverse extent of atlas 0165 1 longitudinal 0040 Diameter centrum of anterior dorsals transverse 0050 ( vertical 0028 Transverse extent with diapophyses 0110 Total elevation (oblique) 0130 Elevation of neural canal 0028 Length of centra of four consecutive dorsal vertebrje, including spaces for intervertebral discs. .0190 Diameter of head of humerus^ ^°°S 0090 ( short 0075 Long diameter of shaft 0045 Transverse diameter of distal extremity 0110 Transverse diameter of distal condyles ^ 0070 vertical 0045 transverse 0065 Length of prsesternum 0150 Widthofpr and superior aspect of the muzzle are regularly convex in ti-ansverse sec- tion. The inferior incisive alveolus is inclosed entirely in the plane of the ramus, and extends posteriorly to below the last molar tooth. The masse- teric ridge is ver}' oblique, and rises to a median point below the second molar. The coronoid process rises from the front of the last molar. Measurements. M. Length of superior molar series 008 „• . i. , • , < anteroposterior 004 Diameter of second superior molar ■; ' < transverse w6o _. , i- X, • 1 1 (anteroposterior 0020 Diameter of third superior molar.; ' ... < transverse uu-jo Width of superior incisor 0020 Length from base of tirst superior molar to base of incisor 0065 Width between bases of first molars 002O Length of first inferior molar 0033 Depth of ramus at second molar 0050 Width of ramus below second molar 0035 This species was evidently abundant during the early Miocene period in Oregon. I have received numerous specimens from the John Day region from Messrs. Sternberg and Wortman. Meniscomys liolophus Cope. Bulletin U. S. Geol. Survey Terrs., VI, p. 366. Plate LXIII; fig. 11. This species is known from a crushed skull, which displays the second, third, and foui-th superior molars and the superior incisor in good preserva- tion. The superior molar teeth indicate that this is the largest species of the genus. Their characters place it between the extremes of form represented by the 3L hippodus and the Jf. iiitens. The crowns of the teeth are short, and the roots are long. The external V's are distinctly inflected, and are separated by a deep notch. The external dividing ridge is not prominent, and the posterior V is smaller than the anterior. The internal lobe is a simple raised border, which would be crescentic in section. It sends a ridge inwards to the anterior intermediate tubercle. The intermediate tubercles are low cones, and the posterior is connected with the apex of the posterior V by a low, simple ridge. The entire absence of crenations and plications of the crests and lobes of the superior molars distinguishes this species from the M. cavatus and M, 830 THE JOHN DAY FAUNA. nifens, but the details differ from those of 31. hippodus in quite as great a degree. Thus, the intermediate tubercles are lower and more conic, and the external enamel border is not produced so as to inclose lakes, as in that species. Other portions of the dentition are not determinable, except the superior incisor. This is moderately compressed, and has a regularly convex ante- rior face, without grooves. Measurements. M. Leogth of three large anterior molat teeth 0095 „. . m o < anteroposterior 0036 Diameters of Pm. 21 ^ „„., , ( transverse UOdss Diameters of M. 2 j '*°'«°P°«t«''°' ^^0 t transverse ..'. 0040 Width of anterior face of superior incisor 0020 Meniscomys cavatus Cope. BtJletin U. S. Geol. Surv. Terrs., VI, p. 366. Plate LXIII; figs. 12-15. A concretion contains a number of limb bones and a mutilated skull of this rodent. The latter displays the entire dentition of one side, in both jaws. Besides the characters of dentition which distinguish this species, the ear-buUse differ from those of the M. Jiippodus. They are, as in that species, very large and somewhat compressed, but they differ in being transversely divided by bony laminae of no great depth, which give a sacculate appear- ance like that of a colon, with the difference that the external surface is not grooved at the bases of the partitions. The superior surface of the skull is flat; there is no sagittal crest, and there is a well-marked postorbital angle. The interorbital surface is plane. The occipital condyle is narrow, and is separated from the otic bulla by a space as wide as itself The basi- occipital is not excavated, but has a low median keel-angle. The superior molar teeth are all posterior to the anterior border of the orbit, excepting the anterior lobe of the second premolar. The anterior V of the second premolar is the largest; while on the last molar the anterior V only is present, the place of the posterior one being occupied by a flat space. There is a short external rib separating the two external V-faces. On the grinding surface of the molars it is evi- dent that the posterior intermediate tubercle is represented by two crenate SGIUEOMOEPHA. 831 ridges, which are connected with each other and with the posterior external V by a zigzag ridge. The anterior intermediate tubercle is an enlargement of a crenate ridge which connects the internal edge with the external ante- rior V. In the inferior series the molars have those lobes on the edge of the inner side, of which the middle one is the least prominent. There are two better defined lobes on the external margin. The crowns are basin- shaped, and although the enamel is wrinkled in a complicated manner, the wrinkles are not elevated, as in the other species of the genus. Thus the inferior molars more nearly resemble those of ordinary Sciuridce than do those of the other species of Meniscomys. The inferior incisor is much compressed. The inferior border of the masseteric fossa is well marked and ter- minates forwards below the middle of the second molar. The base of the coronoid rises opposite the posterior pai*t of the third molar. A femur has a cylindrical shaft. The distal portion is not elevated, and the rotular groove is rather wide and with equal lateral ridges. The condyles are narrow anteroposteriorly, and are spread well apart. A broken tibia is quite elon- gate, and the distal part of the shaft is subcylindric. The proximal part is triangular in section. The inner side above is a little concave, the posterior side is a little more concave, while the external side is rather strongly con- vex. The crest is not prominent. Measurements. u. Width of skull just behind postorbital angles 0066 Length of otic bulla 0115 Width between otic bullse 0038 Length of superior molar series 0083 Diameters second molar J ''°*«^<'P°«t«"«' 0028 c transverse 0023 Diameters last molar 5 '»°'«r°P°«t«"'''- 0023 < transverse 0020 Length of inferior molar series 0090 Diameter third molar ^*''''"^^*'""«--. 0018 < anteroposterior 0025 Width of inferior incisor 0010 Depth of ramus at front of Pm. iv 0040 Depth of ramus at front ofM. iii 0060 Width of condyles of femur 0060 Depth of condyles of femur 0050 Depth of fragment of tibia 0320 Diameters head of tibia I '^°**"^''P°«*«^'°' "060 < transverse 0060 From the John Day River region, Oregon. 832 THE JOHN DAY FAUNA. Meniscomys nitens Marsh. Allomya nitena Marsh, Amer. Journ. 6ci. Arts, 1877, September, p. 253. Mesniscomyt multiplioatm Cope. Proceedings Amer. Philosoph. Society, 1878, p. 68. Plate LXIII; figs. 16-17. Represented in my collections by fragmentary jaws of eight individ- uals, two of which contain superior molar teeth. These indicate a species which has some range of size, and which may be nearly as large as the M. lioloplius. The characteristic peculiarity of this species is, that there are two much crenate intermediate tubercles on the posterior side of the superior molar tooth, which are connected by a ridge with the posterior V ; and that the anterior intermediate tubercle is part of a crenate ridge which connects the inner crescent with the anterior V. The external face of the crown is prominent at the notches between tlie Vs. The inferior molars are bilobate on the external side, and while the inner sides of the crowns are flat, their superior edge is trilobate. The grinding-face is much complicated by enamel ridges. Four crescentic areas are discernible on the worn surfaces of the crown, of which the posterior is reduced in size on the middle two molars. The two inclosed lakes have very plicate borders which form many small loops, and sometimes they are fnsed into a single irregular area. The last molar is extended a little poste- riorly, and all present an entrant angle between the inner columns. The coronoid process originates opposite the third molar, and the masseteric ridge ceases below the middle of the jaw below the second molar. Measurements. M. Length of Pm. iv and M. i 0060 _,. , !• n • < anteroposterior 0040 Diameters of Pm. w I *^ ,,., „ < transverse UU4U _^. , -„ T i anteroposterior 0020 Diameters of Pm. I. •; , ^ ..,_ ( transverse 0U4U Probable length of inferior molar series 0120 Length of posterior three molars 009.5 .^. ^ . , , (anteroposterior 0030 Diameter of second molar { , '^ .^. c transverse OOa."! Length of fourth molar 0040 Depth of ramus below second molar 0070 Width of ramus below second molar 0050 SCIUKOMORPHA. 833 The above measurements are taken from the largest specimens. In some of the smaller ones the length of the anterior three inferior molars is .0085, and in one instance .0080. I think that it was on a specimen of this species with the last-named measurement that Professor 0. C. Marsh estab- lished his Allomys nitens. The species was very briefly described, but may be recognized by an accompanying figure. A new generic name was pro- posed, but no characters were given, and it was even made the type of a new family, but no reasons for this course were adduced. ISCHYROMYS Leidy. Proceed. Acad. Nat. Sci. Philad., 1856, p. 89 ; Extinct Fauna Dakota and Nebraska, 335. — Colotaxis Cope, Paleontolofjical Bulletin, No. 15, p. 1. 10 5 Ohar. gen. — The essential features are, dentition, I., ; C, - ; M., - ; the molars with two crescents on the inner side above, each of which gives rise to a cross-ridge to the outer margin. In the mandibular series the crests and crescents are identical, but in a reversed relation. No cementum. To the above characters given by Dr. Leidy, I have added the absence of postfrontal processes, and the superior position of the infraorbital fora- men; also that the pterygoid fossa is large, and that its inner and outer plates are well developed, and subequal. The palate is excavated posteri- orly. The acuminate anterior part of the malar bone extends as far for- wards as the front of the orbit. There is no tuberosity on the side of the superior diastema near the premolar teeth. In the mandible the posterior extremity of the incisive alveolus is not distinct from the ascending ramus. In Hayden's Bulletin, vol. vi, I described some of the characters of the remaining portions of the skeleton. Those which I possess are the distal extremities of humeri, and a tibia, astragali, and portions of the pelvis. The condyles of the humerus are narrow anteroposteriorly. The internal flange descends at once to the fundus, leaving a long external cylindrical roller without intertrochlear ridge. Anteriorly this portion is cut into for half its length by the ligamentous fossae. There is a large internal epicon- dyle, which is constricted by a neck at the base, and presents a compressed edge inwards and upwards. The arterial canal opens above on the interior side of the humerus. There is no external epicondyle. 53 c 834 THE WHITE EIVEE FAUNA. The section of the ilium at its base and at its middle, is triangular. There is an angle along the middle of its external face which supports a moderately prominent tuberosity, a little above the acetabulum. On the anterior mai-giu a little higher up, is a short, compressed, rather prominent process, whicli j^robably represents the anterior inferior spine. From this point posteriorly the internal face of the ilium is deeply concave, producing an attenuation of the inner wall of the acetabulum. The ischium is rather narrow at the base. The distal portion of the tibia is much like that of Ardomys, Gymnop- tyckus, and other Sciuridce. The posterior median process is very large and is shallowly grooved ; the usual deep tendinous groove separates it from the internal malleolus. The trochlear grooves are deep and well separated ; the fibular surface is short. The head of the astragalus is horizontally oval, and is separated from the trochlear portion by a neck of moderate length. Ii extends obliquely inwards, so that the internal margin of the head is in- terior to the line of the inner margin of the trochlea. The sides of the latter are vertical. It is considerably wider than long ; the trochlear carinae are marginal, and the external is considerably more elevated than the inner. The separating groove is profound but open. The posterior inferior fossa is small and foramen-like. Besides the very different form and position of the infraorbital foramen, this genus differs from Gymnoptychus in the excavation of the posterior edge of the palate. Dr. Leidy remarks that this genus belongs to the family of the Sciuridce. This is indicated by the dental characters ; but in some other respects there is a greater divergence from the squirrels and marmots than is the case with the preceding genus, Gymnoptychus. Thus, the large foramen infraorhitale anteritis occupies the elevated position at the origin of the zygomatic arch seen in the porcupines and cavies. There is no superciliary ridge nor post- orbital process as in most Sciuridce, but the front is contracted between the orbits in the same manner as, but to a less degree than, in Fiber, and the Eocene Plesiarctomys, Brav. Both the last named and Ischyromys present many points of resemblance to Pomel's tribe of Protoniyidce, but differ from any of the genera he has included in it. SCIUEOMORPHA. 885 Thia family is thus defined by Pomel :* " infraorbital foramen large as in the HystricidcB, and by the position of the angular apophysis of the man- dible almost in the general plane of the horizontal ramus. The jugal bone, at least in those species where we have observed it, is very much enlarged at its anterior poi-tion, and the orbit is almost superior." These characters apply to Ischyromys, excepting as regards the malar bone, which is principally unknown in the latter. Another family, the Ischyromyidce, has been proposed by E. R. Alston for the reception of this genus, to which he thinks with mef Plesiardomys {■=zPseudofo)»us) should be referred. He thus defines the family:! "Den- tition as in Sciuridce; skull resembling Castoridce, but with the infraorbital opening large, a sagittal crest ; no postorbital processes ; palate broad ; basioccipital keeled." Doubtless Ischromys belongs to an extinct family, but which of the above names is available for it I do not yet know. I would characterize it as follows : Dentition as in Scmridce; infraorbital foramen large, superior; ptery- goid fossa large, with well-developed exterior as well as interior walls ; a sagittal crest. The superior position of the infraorbital foramen and the well-devel- oped pterygoid laminae are characters found in the Muridoe. But one species of this genus is known. Ischyromys typus Leidj^ Proceedings Academy Philada. 1856, p. 89. Extinct Fauna of Dakota and Nebraska, 1869, p. 335. Cope Annual Report U. S. Geol. Surv. Terrs. 1873 (1874), p. 477. Colotaxh criatatus Cope Paleontolog- ieal Bulletin No. 15, p. 1. Gymnoptychus ckrysodon Cope, Paleontological Bulletin No. 16, p. 5. Plate LXVII ; figs. Ul-2. The principal characters of this species have been given by Dr. Leidy «s above cited. I i-epeat the most important of these, and several which have not been previously noticed. In the molar teeth of both jaws there is no transverse crest arising from the connection between the adjacent horns of the crescents. The ' Catalogue Method, et Descr. de Vertebras Foss. de le Bass, de la Loire, 1853, p. 32. t Annual Rei)ort U. S. Geol. Survey Terrs. 1873 (1874,) p. 477. ; Proceed. Zool. Society London, 1676, p. 78. 836 THE WHITE RIVER FAUNA. transverse crest from the anterior horn of the anterior crescent is largely developed in both jaws, while that proceeding from the posterior horn of the posterior crescent is united at both ends with the adjacent one. On the last superior molar, the posterior of the two principal cross-crests is shortened, and the posterior marginal crest is cut off from the inner crescent by a notch. In the premolar of the inferior series, the two anterior cross- crests, are wanting and are replaced by two adjacent cusps, an internal and an external. The incisive foramina are short and rather wide. There is no tuber- osity on the side of the superior diastema as in most Sciuridce. There is a well-marked fossa above the first premolar, and below the foramen iufraor- hitale exterius. The anterior part of the zygomatic arch is convex above and flat below, and at right angles to the long axis of the skull. An osseous bar extends outwards and backwards from the external base of the external pterygoid ala; whether it spans an alisplienoid canal I cannot determine. The palate is excavated as far as the posterior border of the last superior molar tooth. The ascending portion of the premaxillary bone is wide. The area of insertion of the masseter muscle on the mandible, is feebly defined, extending only to the posterior border of the second molar. The pterygoid fossa of the ramus is on the other hand, deeply excavated. The ascending ramus commences opposite the third molar. The dental foramen enters some distance behind the last molar on a level with its summit, and above the angular superior l)order of the pterygoid fossa The mental foramen issues behind the middle of the length of the diastema and above the middle of the vertical diameter of the ramus at that point. The section of the superior incisor teeth is a nearly regular oval, a little flattened on the inner side near the front. The anterior face presents a very shallow median longitudinal concavity. The enamel is nearly smooth, andis wrapped on the inner side for a moderate width. The inferior incisors are more oblique on the exterior side anteriorly, and are therefore naiTower in front than the superior. The enamel is smooth, presents no- sulcus, is wrapped in a narrow band on the inner side, and on half the entire width on the outer side. There are differences in the form of the inferior premolar, some being^ SCIUROMORPHA. 837 a little wider anteriorly^than others. On a specimen presenting the narrowed form the name cristatus was proposed. In some specimens the inferior incisors are more compressed than in others. In some of the specimens the original bright-bay color of the enamel of the superior and inferior incisors is beautifully preserved. Measurements. M. Length of inferior mol.ars 0.0140 Length of penultimate molar .0033 Width of penultimate molar 0035 W'iiith of first molar 0030 Length of first molar 0035 Depth of jaw at penultimate molar 0090 Depth of incisor-tooth .0040 Width of incisor-tooth 0020 The olecranar fossa of the humerus has a small perforation. There are two small rather deep fossae on the posterior aspect of the humerus distally ; the larger is at the base of tlie epicondyle, the other is within and a little above it. The marginal crest from the external epicondylar region is arcute and rather elongate. The shaft of the humerus above it is quite slender. In a second specimen, the inner of these two fossae is wanting. At the middle of the shaft of the tibia, the anterior and external faces meet at a right angle ; the inner and posterior, faces. Jorm a nearly continuous curve. The inner crest of the posterior distal process, which bounds the sulcus tendinis flexoris longi poUicis is not so produced as in Gymnoptyclms minutus, or Ardomys monax. The humerus bears considerable resemblance to that of both these species, but differs from both in the presence of the posterior fossae. In Ardomys monax the arterial foramen is wanting. Measurements. u. Diameter distal end of humerus ^^°'«^''P"^*'^"''^ *^50 ( transverse 0190 Length of internal epicondyle 0060 Diameter distal extremity tibia ^ anteroposterior 0060 ( transverse 0080 r.. . r, r i- < exterointernal 0060 Diameter of base of uium ^ ( anteroposterior 0065 Anteroposterior diameter of aeetabnlnm 0065 Length of astragalus (axial to foot) 0100 Length of astragalus obliquely 0115 Width of trochlea of astragalus 0060 Width of head of astragalus 0045 Elevation of external arc of astragalus 0045 838 THE MIOCENE FAUNA. ' This squirrel was about as large as the existing Sciurus niger. It was common during the White River epoch, specimens having been obtained in Dakota, Nebraska, Wyoming, and most abundantly in Colorado. CASTOR Linn. Syst. Nat. I, p. 78, 1766.— Cope, Bulletiu U. S. Geol. Surv. Terrs., VI, p. 368. Steneofiber, E. Geoffr., Revue Encyclop^dique, 1833. — " Chalicomyn Meyer, Nenes .Tahrbuch, 1838, p. 404, et 11^46, p. 474." — Palceocastar Leidy, Extinct Jlamnialia Dakota JuiU Nebraska, 186y, p. 338. The family of the Castoridce differs from the Sciurklce in the absence of postorbital angles or processes, and the presence of a prolonged tube of the meatus auditorius extemus. In both of these points it agrees with the Hap- lodontiidce, a family which Mr. Alston has distinguished from the Castoridce on various grounds. I do not think any of his characters are tenable, ex- cepting that drawn from the form of the mandible, which is expressed thus in Mr. Alston's diagnosis : "Angular portion of mandible much twisted " I have described this character better as follows : Angle of mandible with a transverse edge due to inflection on the one hand, and production into an apex externally ; the inflection bounding a large internoposterior fossa. Mr. Alston enumerates four genera of Castoridce — Castor, JJiohroticus, Steneofiber, and Castoroides. J. A. Allen has shown that the last-named genus cannot be referred to this family. The characters of Diobroticus, as given by Alston, are as follows : " Skull much as in Castor. Third upper molar and lower premolar elongate, with four enamel folds, the rest with only two ; all the folds soon isolated." This diagnosis appears to separate the genus satisfactorily. The definition of Stemofiber is as follows : " Parie- tals not parallelogrammic ; interparietal subhexagonal ; basioccipital not concave ; grinding teeth as in Castor, the subsidiary folds sooner isolated." The distinction from Castor here rests exclusively on the forms of the parie- tal, interparietal, and basioccipital bones. This kind of definition is always of questionable validity, as the terms " parallelogrammic," " hexagonal," &c., are not intended to be exactly used and cannot be exactly applied. The Castor (Steneofiber) peninsulatus illustrates this fact, for there is no strik- ing difference in the forms of the two bones to which these terms are ap- plied, as compared with the Castor fiber. The basioccipital bone differs from SCIUROMORPHA. 839 that of the beaver, but not so as to conform to J. W. Alston's diagnosis ot the genus 8teneofiber. Its inferior surface is concave, but doubly so, as a keel occupies the median line. In the -S^. viciacensis according to Filhol, this region is shallowly concave, without median keel. Although important as specific characters, these variations do not appear to me to require the rec- ognition of as many genera. The possession of the epitrochlear foramen in the S. viciacensis is at first sight an important character. Mr. Filhol, how- ever, informs us that of thirty-four humeri which he has studied, sixteen possess the foramen, and in eighteen it is wanting. The Castor tortus was described by Leidy from the Loup Fork forma- tion. He coined the subgeneric name Eucastor for it without corresponding definition. In his monograph of the Castoridce, J. A. Allen referred this species^ to a genus distinct from Castor, and defined it, using for it Leidy 's name Eucastor. This genus appears to me to be valid. The three genera of Castoridce will then be defined as follows : Molars and premolars with one inner and two or three outer folds Castor. " Inferior premolar and third superior molar elongate, with four enamel folds ; the rest with only two " Diohroticus. Superior premolar enlarged, with one inner fold ; inferior molars small, with two lakes Buca.stor. Some affinity probably exists between this family and the MylagauUdce, which followed in the Loup Fork epoch. The species of Castor may be distinguished as follows. I do not know the C. nebrascensis^ from the White River, nor the occipital bone of the C. pansus^ from the Loup Fork formation. I. Basioccipital bone deeply concave below, simple ; Angle of lower jaw not deflected C. fiber. II. Basioccipital shallowly concave below: Angle of lower jaw deflected C viciacensis. III. Basioccipital concave below with a median keel; angle of lower jaw not deflected. Palate wider ; size medium C. peninsulatutr. Palate narrower ; size small C. gradatus. ' Monographs of North American Rodentia, Coues and Allen, U. S. Greol. Surv. Terrs., 1877, xi, p. 450. '^ Steneojfber nebrascensis Leidy, Proceed. Academy Phi la., 1856, 89; 1857,89; Chalicomya nebraseeiisis Leidy, 1. c, 1857, 17(); J'alaocaetor nehrascensis Leidy, Ext. Mammalia Dakota and Nebraska, 16U9, p. 338, xxvi. Figs. 7-11. Steneofiber pansus Cope, Report Capt. G. M. WTieeler, iv, pt. ii, 1877, p. 297. 840 THE JOHN DAY FAUNA. Castok peninsulatus Cope. Bulletin U. S. Geol. Survey Terrs., 1881, VI, p. 370. American Naturalist, 1883, p. 53, figs. 9, 10. Steneofiber f nebraacensis Cope, loc. cit., 1879, p. 55. Plate LXIII ; figs. 18-21. This species is about tlie size of a large prairie marmot — Cynomys ludovi- ciamts. It was abundant in Oregon during the period of the John Day Mio- cene. Leidy originally described the closely allied C. ?iebrascensis from tlie WhiteRiver beds of Nebraska, but I have never obtained it from that for- mation. Another and similar species, C. pansus Cope, is common in the Loup Fork beds of Nebraska and New Mexico. Several well-preserved skulls from Oregon display characters not visi- ble in specimens heretofore collected, and which enable me to make fuller comparisons with the European C. viciacensis, so fully described by M. Filhol.i The postorbital constriction is much greater in this species than in the C. viciacensis, and greater than in the C. nebrascensis from the White River beds. The straight anterior temporal ridges are in line with the superciliary borders, and unite into a sagittal crest at the constriction. In the S. vicia- censis they continue separate beyond this point one-fourth tlie distance to the supraoccipital crest. The zygomata are wide, and the malar ridge is very prominent anteriorly, overhanging the face, and curving rather abruptly to the base of the muzzle. The latter is rather wide, with parallel sides, and is flat above. The brain-case expands rather abruptly from the inter- orbital constriction, and is rather flat above. The infraorbital foramen is a narrow vertical oval and is situated low down in the vertical line Avith the anterior extremity of the malar angular edge. It is a little nearer the line of the first molar than the posterior border of the superior incisor. The incisive foramina are relatively larger than in the beaver, and are chiefly in ihe premaxillary bone. The palate between the anterior molars is as wide iis the transverse diameter of the first molar. There is no distinct fossa of the maxillary bone in front of the orbit as represented by Filhol in the C. ■viciacensis. The pterygoid fossa is wide, with the inner process the longer, ' £tude des Mammif ^res Fossiles de Saint-Grand-le-Puy AUier. Bibl. de l'£cole des Hautes £tudes, XIX, Art. I, p. 44, 1879. SCIUROMORPHA. 841 and reaching the otic bulla. The latter are large and obliquely placed ; the meatal borders are produced into a short tube, which is not so long as that of the C. fiber. Its superior border is quite prominent, overhanging the inferior, and projecting more than represented by Mr. Filhol in the C. vicia- censis. There is a strong ridge of the squamosal bone extending posteriorly from the base of the zygomatic process, which overhangs a fossa. This fossa is further defined posteriorly by the tympanic tube. This fossa is larger and deeper than in either C. fiber or C. viciacensis. Below its superior bounding ridge is a large subsquamosal foramen. The mastoid bone is distinctly exposed between the squamosal and occipital, and its surface is separated from that of the former by a groove which is not so well marked in the C. fiber. Its inferior angle is in contact with the bulla, and is shorter than the paroccipital process. The latter is short, not extending below the line of the condyles, and is directed downwards, not posteriorly as in C. fiber. The occiput is nearly vertical and flat, excepting laterally, where there are two fossa?, a superior and inferior, the latter the longer, and ex- tending to the inferior surface. The premaxillo-maxillary suture is just half way between the anterior molar and the superior incisor, and is vertical to opposite the middle of the incisive foramen, and then turns backwards. The frontomaxillary and frontonasal sutures are in one transverse line across the front. The malar- maxillary suture is behind the anterior border of the zygoma, thus con- fining the malar bone to the zygoma. The latter is much expanded in a vertical direction, but has no postorbital angle, resembling in this respect the C. viciacensis rather than the C. fiber. Its posterior portion extends well posteriorly and below almost all of the squamosal part of the zygoma. The parietal is of a parallelogrammic form; the anterior inner border cut obliquely by the frontal, and the posterior inner border cut out for the supraoccipital. The latter bone has an oval form, narrowed anteriorly and truncate posteriorly. I describe a mandibular ramus of a second individual. It unfortu- nately has the coronoid and the angle broken off. The base of the latter is concave on the inner side. The external face of the ramus is every- where convex. The base of the coronoid is separated from the molar line 842 THE JOHN DAY FAUNA. by a wide groove. The anterior base is opposite the second molar. The incisive alveolus is continued upwards and backwards, and ceases in a pro- tuberance which is external to the plate which connects the condyle with the coronoid process, and is separated from it by a fossa. The condyle is subglobular, and has considerably more external than internal articular surface. The series of inferior molar teeth is quite oblique, descending- posteriorly. Dentition. — The grinding surfaces of the superior molars are none of them longer than wide, and in all but the first, the transverse diameter exceeds the anteroposterior. The dimensions diminish posteriorly in all the measurements. There is one inflection of the sheathing enamel on each side of the crown in all the molars in their present state of wear. The positions of the lakes indicate that in an earlier stage there were two external inflections. At present all the molars display a fossette external to the fundus of the internal inflection. Besides this there are two others in the first molar, and one other in the fourtli. Posterior to the external inflection there is one fossette in the first and third molars, two on the fourth, and none on the second, where it is probably worn out. According to Leidy there are three in this position in all the molars in the C. nehras- censis, and two in the position first described. According to Filhol, there is but one in each position, in about the same stage of wear, in the C. vicia- censis. The inferior molars display a deep external inflection, and three trans- verse lakes on the inner side. These probably represent inflections at an earlier stage of wear; the median one is still continuous with the sheathing enamel on the first molar (Pm. IV). The sizes of the inferior molars increase anteriorly regularly, excepting that the first is relativel}' a little longer than the others. Measurements of skull. u. Length from inion to edge of nasals 067 Length from edge of nasals to interorbital constriction 034 Length of muzzle to preorhital angle of maxillary 018 Width of skull at paroccipitals 025- Width of skull at posterior edge of squamosal 034 Width at zygomata posteriorly U56 Width at interorbital constriction 006 SCIUROMORPHA- 843 u. Width between anterior parts of orbits 027& Widtb at base nf muzzle 01& Length from occipital condyle to front of otic bulla, inclusive 018 Length from bulla to last molar tooth 00& Length from first molar to base of incisor O-iS Length of superior molar series 0195 Diameters of first molar 5 '"'^"°P°^^"'°'" -' " Z^a^ ( transverse W4o Diameters of fourth molar) ''"''■^"P''«t^"'"- " ^^ ( transverse WJa Measurements of mandible. Length from condyle to incisor tooth 039O Length from incisor to Pm. iv - - 0105 Length of inferior molar series 0145 Diameters of Pm.iv^''°«»^'-''P*'«'"'°'- Z*^. < transverse uu4ir Diameters of M.i^''"^"''!'"^"^"'"' ZJL < transverse wnv Diametersof M. ii^''°t"»P''«t*^"'"^ ^^ < transverse • uuda Depth of ramus at diastema OlOO Depth of ramus at Pm. iv 0130 Depth of ramus at M. iii OlOO A few bones accompany the mandible, all having been cut from the same fragment of matrix. The head of the femur is perfectly round, and is bounded by a well-defined neck. The great trochanter incloses a large fossa. The lesser trochanter is large; the third trochanter is not prominent as it is in C. viciacensis. The shaft is generally flattened, with its long diameter transverse. The condylar extremity is flattened, and the rotular groove is wide, and the condyles well separated. The epicondylar angles are distinct, but not so prominent as in S. viciacensis (see Filhol, I. c, PI. VI, Figs. 1 3, 1 4). The general form of the femur is robust, as in that species. The distal extremity of the tibia resembles that of Sciuridce generally, especially in the large size of the external postei-ior angle. Its diameters are small, and the distal part of the shaft is slender and subcylindrical. The crest extends well down from the proximal end, being much stronger than in the true squirrels, and bounds a longitudinal fossa. The fibular facet of the tibia overhangs extensively, and bounds a rather narrow proxi- mal fossa. This continues into a narrow shallow groove on the posterior face of the shaft, which disappears near the middle of its length. The proximal half of the shaft is much compressed. The inner face is smooth 844 THE JOHN DAY FAUNA. and gently convex. The crest sinks rapidly into the head, and the femoral facets are well separated. The tibia resembles that of C. viciacensis, but is more compressed in its proximal half Measurements of hind leg. M. Length of femur .057 Width of femur at head 019 Width of femur shaft below third trochanter 009 Width of femur at epicondyles 015 Width of condyles of femur 013 Anteroposterior diameter at condyles .011 Anteroposterior diameter of head 009 Diameters of head of tibia ^'*°*''^"P"«'"''"' "l^ ( transverse 014 Diameters of distal end of tibia ^'"'t^^^P"^^'""^ '^^^ ( transverse 0085 . . .. ■ 1- i ( above middle .. 010 Anteroposterior diameter < - ( transverse 0024 Diameter of third molar ^ anteroposterior c transverse From the above measurements it is apparent that the molar series in. this species is equal in length to the anterior three molars of the S. nehras- censis and S. pansiis. The posterior fossettes of the crowns seen in those- species are wanting in the S. gradatus. From the John Day Rivev, Oregon. HELISCOMYS Cope. Synopsisof New Vertebrata from Colorado (Miss. Pub., U. S. Geol. Survey Terrs.), 1P73 (October), p.Sj. Annual Report U. S. Geol. Survey Terrs., 1873 (1874), p. 475. Inferior molars four, rooted, the crowns supporting four cusps in trans- verse pairs A broad ledge or cingulum projecting on the external side^ 846 THE WHITE EIVER FAUNA. from base of the cusps. The inferior incisor compressed, not grooved, and with the enamel without sculpture. This genus is only represented by a small number of specimens, which are mandibular rami exclusively. Its special affinities, therefore, cannot be ascertained, and even its general position remains somewhat doubtful. There is some probability, however, that it belongs to the Myomorpha, as the type of dentition is much more like that of the genera of that group than those of the Sciuromorpha. To the Hystricomorpha it does not belong. As compared with known genera of Myomotpha, it is at once separated from many of them by the presence of a premolar tooth. Among recent genera of this suborder, Sminthus possesses this tooth in both jaws, and Meriones in the upper jaw only. It is present in both jaws in the Sciuro- mopha generally. The tubercles of the teeth resemble those of the Muridm, but their disposition is unlike that of any existing North American genus. A remote approximation to it is seen in the genus SyllopJwdm of the Bridger Eocene formation, where there are four subquadrate molars with tubercles; but the latter form two transverse crests, with an additional small inter- mediate tubercle, and the wide cingulum is absent. But one species of Heliscomys is known, the H. vetus. Heliscomys vetus Cope. Synopsis of New Vertebrata Colorado, 1873 (October), p. 3. Annual Report U. S. Geol. Survey Terra., 1873(1874), p. 475. Plate, LXV: figs. 14-18. The mandibular ramus is rather robust in its proportions. Neither the alveolar sheaths of the molars nor that of the incisor project beyond the general surface. The anterior base of the ascending ramus commences opposite the anterior part of the last molar tooth. The masseteric fossa extends remarkably far anteriorly, its inferior border terminating close to the mental foramen. This border is moderately raised, and extends down- wards and backwards, not reaching the inferior border anterior to a point below the anterior base of the ascending ramus. The symphysis rises at an angle of about 45°, and the inferior border is very little convex to below SCIUEOMORPHA. 847 the last molar. The foramen mentale is situated near the superior plane of the diastema, half way between the alveolar borders of the incisor and pre- molar teeth. The grinding face of the molar series rises slightly anteriorly. The sections of the middle two molars are subquadrate and are of equal size. That of the fourth is smaller by one-third; having the same longitudinal extent, but less width, thus forming a longitudinal oval. The section of the premolar is round, and its diameter is half that of the long diameter of the other molars. The premolar has two contiguous roots, and three conic cusps, one anterior and two opposite and posterior. The cusps of the other Tuolars are separated transversely by a deep notch, and longitudinally by a iissure, which does not invade the surface of the cingulum. The latter extends a short distance round the anterior base of the crowns of the second and third molars. The crown of the fourth molar is worn or injured in my specimens, so as not to be described. The incisor is strongly compressed, -as in many Muridai, and the anterior face is slightly convex in section. The enamel is smooth, and is abruptly recurved in narrow borders of about *qual width on both the inner and outer sides. On the inner side the sur- face makes a sharp right angle; on the outer side the angle is right, but is obtusely rounded. The surface of attrition is elongate, and displays a small pulp cavity. Measurements. M. Length of incisive alveolus to end of molar series 0050 lieugtli from incisive alveolus to base of ascending ramus 0044 Xeugtli of diastema 0020 JLengtli of third molar 0008 "Width of third molar OOOd Long diameter of incisor OOOS .Short diameter of incisor 0004 Depth of ramus at diastema 0018 Depth of ramus at third molar 0021 Thickness of ramus below the same 0014 The Heliscomys vetus is the least mammal of the fauna of the White Hiver epoch. The mandibular ramus is the size of that of the Mus mus- 'Culus, and its four teeth occupy the same length as the three of the latter species. One of the specimens indicates an individual a little larger than the one above measured. 848 THE WHITE El VEE FAUNA. MYOMOKPHA. EUMYS (Leidy non>) Cope. Annual Report of the U. S. Geological Survey of the Territories, F. V. Hayden in charge, 1873 (1874)^ p. 474. — Eumys Leidy (name only), Procee Report of Lieut. G. W. Wheeler, IV, p. '.m, PI. LXIX, fig. 15 MYOMOEPHA. 849 EuMYs ELEGANS Leidy. Proceedings Academy, Philada., 1856, p. 90; loc. cit. 1857, p. 89. Extinct Mammalia of Dakota and Nebraska, p. 342, PI. XXVI; figs. 12, 13, 1869. Cope Ann. Report U. S. Geol. Snrv. Terrs., 1873 (1874), p. 474. Plate LXV; figs. 1-14. I found remains of this rat exceedingly abundant in the shallow washes of the White River rocks in Eastern Colorado. It had previously been known from a single imperfect jaw-fragment from Dakota, found by Dr. Hayden. The sutures of the cranium anterior to the brain-case are distinct, in- cluding those that separate the frontal and nasal bones on the median line. The suture separating the maxillary and premaxillary bones crosses the palate a little behind the line connecting the bases of the zygomata, passes upwards a little in front of the latter and then turns posteriorly, joining the nasal suture at its posterior extremity. The apices of the pre- maxillary and nasal bones fonn an acute angle above the middle of the orbit, and the frontals enter an acute notch between them. The palato- maxillary suture crosses the palate opposite the middle of the second molar tooth. The nasal bones are strongly convex at the extremity, and extend a. short distance beyond the base of the superior incisor teeth. They narrow posteriorly, become plane, and then concave on the median line. The carina of the frontals incloses a median groove. The superior portion of the maxillary bone presents a subround fossa at the entrance of the fora- men infraorhitale. The latter is overarched by a slender bridge, which is as wide as thick. The malar bone does not appear in the base of the zygoma, whose inferior expansion presents a shallow, wide fossa, downwards and forwards. The anterior border of the base is free, inclosing a fissure which descends from the superior portion of the foramen. The posterior margin of the base is opposite to the anterior part of the first molar tooth, a point which is nearly attained by the incisive foramina. The latter are separated by a narrow septum on the median line. The free border of the palate is slightly concave, but does not advance beyond the posterior part of the third superior molar. The palatine foramen is large, and is opposite the posterior half of the second molar. 54 c 850 THE WHITE KIVER FAUNA. The mandible is robust, and the symphysis is very steep in profile. Its sutural face descends at an angle of 45°, and then exhibits a nigose point of union below the first molar on the inferior border of the ramus. The inferior border is subparallel with the tooth line, but presents an up- ward concavity below the third molar. The coronoid process originates opposite the anterior part of the third molar, is vertical and compressed. The anterior border extends obliquely backwards. The masseteric fossa has a prominent inferior border which extends upwards and forwards to below the middle of the first molar. Its surface is gently concave below, convex above. The ptei'ygoid fossa of the ramus is deep and large. Its inferior border is a spur-like continuation of the inferior part of the ramus, from which the thin outer wall of the fossa rises. The latter is somewhat convex on the external side. The tooth basis and the incisive alveolar sheath do not project much on the inner side of the ramus. The diastema is as long as the tooth line, and the foramen mentale is below a point a little behind its middle. The foramen dentale enters a little above the base of the vertical ramus and three times the length of the last molar behind that tooth. The superior incisor teeth are convex in front, the convexity slightly oblique to the external side. The enamel is smooth and does not overlap the sides. The crescents and cones of the molar teeth are well separated from those of the same side by vertical fissures. A narrow crest connects the base of each cone with the concave side of each crescent. The adjacent horns of the two internal crescents join, and the connecting portion sends a short crest into the interval between the external cones. The anterior and posterior horns of the two crescents are produced transversely, forming the anterior and posterior borders of the crown in the middle molar, the ante- rior border of the third, and posterior border of the first molars. The an- terior or fifth lobe of the first molar is simple. The inner and outer lobes of the third molar are reduced in size, and close together. The last superior molar is only half as large as the first, and the middle molar is interme- diate in size. The molars of the inferior series do not difi'er in size so widely as those of the superior series. They are subequal, but the anterior and posterior are MYOMORPHA. 851 somewhat nan-owed at their extremities. The tubercles of the first and last difier slightly from those of the superior series. The anterior odd one of the first is smaller; while the posterior outer crescent of the third is well developed, with all the transverse crests. The posterior inner cone is, how- ever, wanting. The details of the inferior molars repeat those of the supe- rior series, but in reversed relation, the external portions of the one being the internal of the other, and vice versa. The inferior incisors are nearly as much curved as the superior ones; they are robust and subtriangular in section. The enamel is smooth, and has a convex surface presented more obliquely outwards than the superior incisors. Measurements. M. Depth of skull at middle of orbit, without molar teeth 0.0060 Width between orbits 0050 Length from middle of orbits 0150 Length from front of zygoma 0100 Length of superior diastema .... .0075 Length of nasal bones 0120 Length of superior molar series 0060 Length of first superior molar 0025 Length of third superior molar 0015 Width of first superior molar 0020 Width of third superior molar 0016 Width of nasal bones at middle 0020 Width of nasal bones distally 0030 W^idtli between bases of zygomata 0070 Width of superior incisor tooth 0015 Length of mandible of another individual to dental foramen 0160 Length to end of dental series 0115 Length to front of dental series 0055 Length from base of vortical symphysis to front of pterygoid fossa 0095 Depth at diastema 0050 Depth at middle molar 0055 Length to base of coronoid : 0090 Thickness of ramus on front border of masseteric fossa 0040 Anteroposterior diameter of inferior incisor tooth 0020 Anteroposterior diameter of last molar 0020 Width of last molar 0018 The hundred and more individuals represented by my specimens, evi- dently differed in various minor respects, as in size and robustness. Some, perhaps males, have the muzzle stouter in proportion to the length than others; some are more decurved than others. With molar teeth as large as those of the Norway rat the muzzle of the Eumys elegans is not more than two-thirds as long; so that the species was in general proportions smaller and more robust. 852 THE JOHN DAY FAUNA. HESPEROMYS Waterhouse. This recent genus had a representative in the John Day Miocene in North America, so far as the characters of" the skull and dentition may be considered to be conclusive in evidence. It is not very probable that the indications thus obtained will be invalidated by other portions of the skeleton. The molars are |, and the crowns support alternating tubercles sepa- rated by shallow open transverse valleys. These are, one on the inner and two on the outer sides of the superior series, and one on the outer and two on the inner side of the inferior. In the recent species, {H. leucopus) there are two inflections on the inner side of the tirst molar, but in the spe- cies here described that tooth is constricted at the position of the anterior internal loop, and does not regain its width, but continues narrowed to the anterior extremity. Tlie infraorbital foramen is rather large. It is probable that there is a second species of this genus in the Loup Fork beds besides the H. loxodon Cope. Hesperomys nematodon Cope. Paleontological Bulletin No. 31, p. 1, Dec. 24, 1879. Proceedings American Philosoph. Soc, 1879-'80,. p. 370. Plate LXVI; fig. 33. . This rat is represented by a beautiful skull, discovered by Prof. Thomas Condon, of Eugene City, and by several jaws and other fragments subse- quently found by Mr. Wortman. The frontal region is not contracted as in JEumi/s clegans and Fiber zibethicus, but the superciliary ridges are well separated from each other, as in Hesperomys americanus. The frontal and posterior nasal regions are slightly concave in transverse section. The molars display tubercles on one side and crescents on the other, the former being external in the supe- rior series. The first superior molar has an additional tubercle at its anterior extremity. The incisors have a transverse anterior face, which is divided by several delicate ridges. Length of superior molar series, .0065; length of first superior molar, .0028; interorbital width, .0042 Length of inferior molar series (specimen MYOMORPHA. 853 No. 2), .0064; length of first molar, .002; width of mcisor, .001; depth of ramus at second molar, .004. The Hesperomys nematodon is about as large as the red squirrel, Sciurus hudsonius, and considerably larger tlian the II. loxodon. PACICULUS Cope. Paleontological Bulletin No. 31, p. 2, Dec. 24, 1879. Procoedings American Philosoph. Society, 1379 (1880), p. 371. Superior molars three, rooted. Enamel forming three entrant loops on the external face of the crown, and one on the internal face. While the number of the superior molars of Paciculus is as in the Murulce, the details of their structure is much as in Basyprocta and Fiber. Two species are known. In the P. lockingtonianus the cranial characters are as, follows: The infraorbital foramen is very large, with a general triangular outline. The superciliary borders and temporal ridges are well separated, and there is no sagittal crest. There are no postorbital processes. The otic bullae are large, and furnished with a ver}^ large meatus auditorius externus. The malar is a narrow bone extending to the glenoid cavity posteriorly, and rest- ing anterioi-ly on a prominent peduncle composed of a maxillary bone. It probably reaches the lachrymal. This genus is probably one of the Muridce, and a near ally of Sigmodon and Neotoma. It diflPers from these genera in having three external inflec- tions of the enamel in the superior molars, instead of two. It differs from Hesperomys as these two genera do, viz, in having deep enamel inflections instead of tubercles and valleys. It is true that the deepening and narrow- ing of the valleys of the molars of Ilesperomys would result after Avear in a pattern like that of Neotoma. The same process in Eumys would produce a pattern much the same as that of Paciculus, but that genus is further characterized by the contraction of the postorbital region and the produc- tion of a sagittal crest. Two species of this genus are known to me, P. wsoUtus, a smaller, and P. locliingtonianus, a larger one. Both are from the John Day beds of Ore- gon. They demonstrate an early origin for the American type of Neotoma, as contemporaries of the first of the Ilesperomys. 854 THE JOHN DAY FAUNA. Paciculus insolitus Cope. Locis citatis. Plate LXVI; figs. 31,32. Size small. Molars regularly and rapidly diminishing in size poste- riorly. Inner enamel loop turned forwards; the external straight and trans- verse, excepting in the first molar, where the anterior column of the tooth is extended forwards, and the anterior loop is turned backwards. No fos- settes. The first molar is longer than wide, and is contracted forwards ; the second and third are subquadrate in form, with the inner angles rounded. The palate is wide, considerably exceeding the long diameter of the first molar. Measurements. u. Length of superior molar series 0060 ( anteroposterior 0021 Diameters of first molar I j^^^^^^^g^ ^,^^3 Length of third molar 0010 Width of palate at first molar 0040 The Paciculus insolitus is about the size of the Chipmunk, Tamias striatus. Paciculus lockingtonianus Cope. Eumys lockingtonianus Cope, Bulletin U. S. Geological Survey, Terrs., VI, 1881, p. 176. Plate LXIV ; fig. 10. This rodent is represented by a nearly perfect skull, which is without jower jaw. Its specific characters separate it widely from the Eumys elegans Leidy and Hesperoniys nematodon Cope. It is considerably larger than either, and the temporal ridges are very obsolete and do not unite posterior to the orbits, as in E. elegans, resembling in this respect the H. nematodon. The parietal region is wide and flat above. The interorbital region is only mod- erately contracted. The muzzle is rather short as compared with the total length of the skull. The interorbital region is gently convex above, and the top of the muzzle is flat. The zygoma is quite slender, and the otic bullae are large and prominent. The notch of the palate extends as far forwards as the posterior part of the last superior molar. The infraorbital foramen is very large and round. MYOMORPHA. 855 The anterior face of the superior incisor is nearly plane, and it is marked by a weak groove near the inner and a strong groove near the external border In E. elegans this face is convex and without grooves. The molars are rather small for the size of the skull ; their crowns are worn by use. The third is subround in section, and its diameter is about half that of the first; the latter has the anterior odd lobe quite small. Measurements. M. Total length of skull 0380 Length (axial) to front of orbits 0140 Length (axial) to palatal notch 0190 Length (axial) to first molar Ol'^O Wiilthat otic bullae 0205 Width at middle of zygomata 0220 Width of interorbital space 00(50 Width between first molars - 0055 Length of molar series 0070 Length of first molar 0030 Width of superior incisor 0015 This species is dedicated to my friend, W. N. Lockington, the well- known natui'alist of San Francisco. ENTOPTYCHUS Cope. Paleontological Bulletin No. 30, p. 2, Dec. 3, 1878; Proceeds. Am. Phil. Soc, 1878-'79, p. 64. Family 8accomyidostparietals nor mastoid foramina. There are deep pterygoid fossae, whose inner bounding laminae unite on the middle of the palatine border, and whose external laminae are con- tinuous with the posterior extremity of the maxillary bone. The otic bullae are not separated very distinctly from the mastoid. The latter looks like a continuation of the former, as in Thomomi/s, and occupies considerable space between the exoccipital and the squamosal. The latter sends down- wards a process just posterior to the auricular meatus, which forms the handle to a hammer-shaped laminar bone. This is, no doubt, a dismem- berment of the squamosal, as a similar process is continuous with that Ijone in Thomomps, and one somewhat different is seen in Neofoma, Hesj^erowi/s, &c. Supraoccipital distinct on superior face of skull Paroccipital process small or none. Mastoid elongate, adherent to otic tube. No postfrontal process. A well-marked character which distin_guislies the skull of this genus from TJiomomys, D'qjodotnys, &c., is the separation of the meatal tube of the otic bulla from the zygomatic process of the squamosal bone by an inter- MYOMOKPHA. 857 space. There is no postsquamosal foramen in the recent genera. In Dipo- domijs tlie otic bulla is more largely developed, but it has the anterior bottle-neck prolongation seen in Entoptychus. In the mandible the coronoid process is developed, but is not large. It is well anterior to the condyle, which it somewhat exceeds in height. The incisive alveolus forms a convexity on the outer side below the coronoid process. The angle is prominent, and is at first incurved below, and then tunied outwards at the apex. The degree of obliquity of the grinding surfaces of the molar teeth vaiy with the species. Parts of several skeletons are in my collection, but I cannot attach them to any cranium. They present the general characters of the genus Thomomys so far as they go. I describe some bones which apparently belong to one individual. The sacral vertebrae carry neural spines. There was evidently a well-developed tail. The scapiila has a narrow glenoid cavity ending in a tuberosity adjacent to the coracoid hook. The spine is robust, terminating in a stout acromion. The tuberosities of the humerus are situated below the head, and are so rounded off as to be little promi- nent. One side of the greater is continued into a very prominent deltoid crest, which terminates abruptly below. The ilium has a narrow trilateral neck, and a projecting anterior inferior spine. The pubis is directed pos- teriorly at the base. The femur is not elongate. Its trochanters are well- marked, including a third. This is wanting in Thomomys hulbworiis. The neck rises obliquely to the rather large head. The condyles are short and spreading, and the rotular groove is short and rather wide, and with well- marked ridges. The tibia is much curved backwards at the proximal part. The crest is acute and is directed outwards, but does not project much at the head. Individuals of this genus were very abundant in Oregon during the middle 3Iiocene epoch. They represent several species, but how many it is difficult to determine. The most noteworthy variations are found in the development of superciliary ridges; then there are modifications in the forms of the premolar teeth, diff'erences in the length and width of the muzzle, and some range in dimensions. 858 THE JOHN DAY FAUNA. The following table represents the characters of the species so far as I can determine them at present: A. Thickened superciliary ridges wanting; front wide. Superciliary borders obtuse, not continued into temporal ridges; front flat, or little concave; premolars narrow. Length of skull .046 E. planifrons. Length of skull .038 E. minor. Superciliary borders sharp, vertical, continued into two straight temporal augles, which form a V. Premolars narrow; size of E. planifrons E. lambdoideus. AA. Thickened ridge on the suijerior side of each supercilium ; front narrower. Superciliary ridges soon discontinued ; size of E. planifrons E. cavifrons. AAA. Superciliary ridges much thickened, soon uniting, and closinf, the frontal groove behind. Front narrowest. Premolar widened at the base; size of E. planifrons E. crassiramis. Some differences in the form of the mastoid bone may be observed in species of this genus. Thus it is flat behind, and bears a well-marked "lateral occipital" angle in E. planifrons and E. lambdoideus, while in the remaining species it is convex, and with the angle little apparent. In some specimens the loss of the hammer-shaped squamosal dismemberment, which I will call the posttympanic bone, gives a deceptive extension forwards to the mastoid. Parts of more than a hundred individuals of Entophjchus are in my collection. Entoptychus planifrons Cope. Paleontological Bulletin No. 30, p. 3, December 3, 1878. Proceedings Amer. Philos. Soc, 1878 (1879), p. 65. American Naturalist, 1883, p. 170, fig. 18. Plate LXIV; fig. 1. A nearly perfect skull, with a portion of a second, are the only speci- mens that I can certainly refer to this species. They represent the largest size found in the genus. The muzzle is long, and gently decurved anteroposteriorly, and slightly convex transversely The length from the side of the orbit at its anterior border to the extremity of the nasal bones is exactly equal to the length from the same point to the inion at one side of the middle line. The front in the more perfect skull is slightly concave, but is without lateral ridges ; in the less perfect specimen it is more nearly flat. There is no trace of MYOMORPHA. 859 temporal ridges, and a delicate raised line represents the sagittal crest. The muzzle is wider above than below, and the superior and lateral faces are separated by a distinct angle, which is acute on the posterior half. In front of the superior part of the orbit is a fossa, which is directed obliquely up- wards and forwards. The fundus of the orbit is not as large as in some species, giving a greater depth to the maxillary bone, which is ah indication of length of the prisms of the superior molars. The palatal surface has two gi'ooves, each of which is continued into a pterygoid fossa. The otic bullae are rather small for the genus, and are flattened behind. Anteriorly they are continued into a neck on each side, which meets its mate of the opposite side on the middle line, resting on the basisphenoid bone. Each neck is pinched off backwards, so that the two inclose an angle between them. The tympanic or meatal tube in this species is very long, exceeding that of any other species, and equaling the long diameter of the bulla witliout the anterior neck. The mastoid adheres closely to the posterior side of the tube, extending to its extremity, and separated from it on the inferior side by a groove. The posterior side of the mastoid is triangular in form, and is nearly flat. Inferiorly there is no groove marking its point of separation from the bulla ; superiorly it carries a strong angle from the inion to its external extremity. The superior face of the brain-case is nearly flat. The occiput is vertical, slightly concave between the points of junction with the mastoid, and with a slight median keel above. The foramen magnum is large, subquadrate, and a little wider than liigh. The basioccipital supports a median keel, and is concave on each side in front of the condyles. The supraoccipital bone has a rather wide triangular exposure. The parietals diverge from the middle line anteriorly, and the suture reaches the squamosal near the posterior border of the orbit. The posterior extremity of the nasal bones reaches that of the premaxillai-ies, and both terminate in line with the deepest part of the preorbital fossa. The superior molar teeth display the typical characters of the genus. Each has an external groove for part of its length, and the anterior column of the last premolar has no anterior production, but has the form of the other teeth. The sizes are, commencing witli the largest, 2-1-3-4. The inferior edge of the angular portion of the mandible is strongly inflected, and the interior face below the molars is concave. The inferior 860 THE JOHN DAY FAUNA. boundary of the masseteric fossa is well mai'ked, and terminates below the anterior border of the first molar. The grinding face of the molars is verj' oblique anteroposteriorly, and that of the first molar is rather smaller than that of the second and third. It has no anterior expansion at the alveolus. The tuberosity of the incisive alveolus is not very prominent. Measurements. No. 1. M. Length of skull from end of uasal bones to occipital condyles, inclusive 046 Length from front of premaxillary bone to base of Pm. iv Oiil Length of molar series on base 009 Length from occipital condyles to junction of otic bullae, inclusive Oil Length of nasal bones , 020 Length of supraoccipital bone 008 Width of otic bulla at middle 006 Length uf tympanic tube 005 Width of muzzle at middle 009 Width of interorbital space C07 Width of slcull at anterior extremity of glenoid cavity 0165 Width of skull at meatus 0205 Width of occipital hone posteriorly 013 Widtli of foramen magnum OOfi Leugtii of inferior molars on alveoli 0080 Elevation of tirst molar above alveolus 0036 Width of crown of second molar .0025 Depth of ramus at third molar 0070 Width of ramus below at third molar 0050 No. 2. Width of interorbital space 007 Width of muzzle at middle 0086 Elevation of skull from second molar Ol:JO Length of inferior molar series 0072 Depth of ramus at M. 2 0072 Widtli of inferior face at M. 2 0043 Width of inferior incisor 0018 Distance between infraorbilal foramen and M. 1 0050 Besides the characters already mentioned, the somewhat greater inter- orbital width distinguishes this rodent from the E. cavifrons. Entoptychus lambdoideus Cope. Bulletin U. S. Geol. Survey Terrs., IV, 330. Plate LXIV; fig. 2. This species is represented by two parts of crania, which include the interorbital and adjacent regions, with the molar teeth. A nearly entire skull presents some of the characters of this species and some of those of MYOMOEPHA. 861 E. cavifrons, so that its validity may be thought to be as yet not entirely be- yond question. In this species, the interorbital region is concave, but there is no ridge- like thickening of the supraorbital border. It presents, on the contrary, a subacute sujjerior edge, flush with the inferior part of the same border. These edges leave the orbital border posteriorly, and converge in straight lines to an acute angle, forming two temporal ridges. The nasal bones do not extend as far posteriorly as the premaxillaries, which reach to the inner line of the anterior border of the orbit. The anterior molar tooth is like the others, and has no anterior basal extension. The size is about equal to that of E. planifrons. Measurements. If. Interorbital ^yidtll 0064 Anteroposterior length of orbit 0100 Depth of skull to alveolar edge 0140 Length of series of suiierior molars • 0070 Width between bases of Pm. iv 0030 The skull above referred to presents the temporal ridges of the typical specimens. It has also lateral occipital angle of the mastoid, as in E. plani- frons, and a meatal tube nearly as long as in that species, differing in both points from the E. cavifrons. But it has a ridge-like thickening of the supraorbital border, as in that species, and the interorbital space has the same relative width. Its size is that of E. cavifrons. Entoptychus minor Cope. Bulletin U. S. Geol. Surv. Terrs., IV, 379. Plate LXIV ; iig. 3. This was an abundant species. Eight more or less complete crania are in my collection, and many fragments present the characteristic meas- urements. It is the smallest species, and is characterized also by the per- fectl)^ flat interorbital region and the absence of temporal ridges. The muzzle of the skull is shorter than in E. planifrons, as may be seen by the measurements, and it is also narrower above, as compared with the interorbital width. The preorbital fossa is not well defined in front. The otie 862 THE JOHN DAT FAUNA. bulla is angulate along the inferior middle line, and has a narrower fonn than that of any of the other species of the genus. The bottle-neck processes send out prolongations, which meet on the middle line below. The mastoid is convex posteriorly, but carries a lateral occipital angle above. The molars of the superior series are. fissured on the external side for a distance, and the anterior is like the others in both jaws. The superior in- cisors are slightly convex anteriorly, and are pei'fectly smooth, except a delicate groove close to the inner border, a character found in most of the other species. The masseteric ridge of the mandible extends as far forward as the line of the front of the first inferior molar, and is well defined posteriorly to near the angle. Measurements. M. Lengt h of skull from front of premaxillary bone to posterior face of mastoid 038 Length from front of premaxillary to base of Pm. iv — 018 Length of molar series on base 0066 Width of otic bulla at middle 0040 Length of bulla and mastoid 0110 Width of muzzle at middle 0080 Width of interorbital space 00.i5 Depth of mandible at M. i 0060 John Day River, Oregon. Entoptychus cavifrons Cope. Paleontological Bulletin No. 30, p. 2. Proceedings American Philosophical Society, 1878 (1879), p. 64. Plate LXIV; fig. 4. I refer portions of six crania to individuals of this species, and seven othei's probably belong to it. It differs from the JE. minor in its superior size, and in the presence of superciliary ridges. These ridges are rarely as thick and prominent as in the Pleurolicus sulcifrons, and do not appi'oacli the development seen in the Entoptychus crassiramis. The postorbital part of the skull is subquadi'ate in outline and depressed in form. The interorbital region is narrowed, but the superciliary margins do not meet nor converge to form a sagittal crest. They are thickened, forming two subparallel ridges which are separated by a shallow concavity of the frontal bone. The nasal bones are very narrow, and their posterior apices just attain the line of the supero-anterior angle of the orbit. The MYOMOEPHA. 863 base of the malar bone is much elevated and very oblique. The otic bulla is flattened on the inner face, as in U. planifrons, and is not so compressed as in the described specimen of E minor. The mastoid bone is convex pos- teriorly, and supports an obtuse keel continuously with the inion. The meatal tubes are broken off, but they were evidently not so long as in E. planifrons. The postsquamosal foramen is large, and is near the posterior lateral ridge of the squamosal bone. The frontal width of this species is less than that of the E. planifrons and E. lamhdoideus, being just half of that of the muzzle at its middle. In most of the crania the nasal bones do not ex- tend so far posteriorly as the premaxillaries. In one of them the sagittal crest is quite prominent ; in others more or less distinct traces of it are visible. The molar teeth are directed obliquely backwards, the alveolus of the first issuing below the anterior part of the orbit. The first superior molar is the largest, but does not differ in form from the others; and the proportions of the others diminish regularly posteriorly. The first inferior molar is a little smaller than the second and third, and is about equal to the fourth ; jts anterior column is contracted ; while the last molar is like the second and third. The face of the inferior incisor is flat, and its enamel is smooth. The external face of the jaw is bounded below by a strong angle as far anteriorly as below the first molar. Measurements. M. Length of skull to incisive alveoli 041 Width of skull at mastoids 020 Width of skull between orbits 005 Width of skull at middle of muzzle 010 Elevation of skull from second molar Oil Length of molar series 007 Length of first molar 002 Width of first molar 002 Length of crown of last molar 0015 Width of crown of last molar 0015 Length from M. 1 to infraorbital foramen 007 Depth of mandibular ramus at M. 2 006 Width efface of inferior incisor , 0016 John Day River region of Oregon. 864 THE JOHN DAY FAUNA. Entoptychus crassiramis Cope. Paleontological Bulletin No. 30, p. 3. Proceeds. Am. Philo. Soc, 1878 (1K79), p. Go. Americ.in Nauralist, 1883, p. 169, fig. 17. Plate LXIV; fig. 5. This species was originally established on mandibular rami. I find^ in my later collections, rami of this character attached to crania, which en- able me to fix the definition of the species with greater precision than heretofore. The skull is about the size of that of E.planifrons, and has a relatively shorter muzzle. The internal orbital walls are rolled inwards at the supra- orbital region so as to meet at a point opposite the posterior border of the orbital space. Opposite the anterior part of the orbit, the ridges are more widely separated, so that the interspace is a narrow wedge-shaped fcssa, opening forwards. There are no temporal ridges, and only a weak sag- ittal crest. There is no preorbital fossa, but the preorbital ala of the maxillary bone is very prominent. Tlie orbital fossa is small and pro.- found, leaving a full depth to the maxillary alveoli. The otic bulla is ovate, and not keeled or flattened. Its size is medium, and its anterior bottle- neck is continuous with the external pterygoid lamina. The meatal tube is elongate, but not so much so as in E. planifrons. The mastoid bone is not distinguished from the bulla by a groove, and it is convex both ver- tically and transversely. It is injured in the specimen superiorly. The superior molars display an external fissure for part of their length. The premolar has the base extended anteroposteriorly more than in any species of the genus. The premaxillo-maxillary suture is exactly halfway between the bases of the incisor and first molar. It is much nearer the first molar in E. planifrons. Measurements. M. Length of craninm from premaxillary to maBtoid, inclusive of both 048 Length from front of premaxillary to Pra. iv 022 Length of molar series on base 008 Length of otic and mastoid bulhe 015 Width of otic bulla at middle 007 luterorbital width 006 AVidth at anterior border of glenoid cavity 017 D«pthof skull atM. i 015& MYOMOEPHA. 865 In the mandibular rami the inferior masseteric ridge extends to below the anterior border of the first molar, and is very prominent and acute. It results that both the exterior and inferior aspects of the ramus are concave to the anterior extremity of the crest, which slopes upwards. The incisive alveolus, though not prominent, as in Hystricomorpha, is on the inner side of the base of the ramus in front. Above the alveolar prominence the inner face of the ramus is gently concave. The anterior origin of the coronoid process is opposite the posterior border of the second molar. In the mandible the condyle projects as far backwards as the angle, and is hence quite a distance posterior to the coronoid process. The latter is small, and is a little higher than the condyle. The angle has an acuminate apex, which is turned out. The posterior extremity of the incisive alveolus forms a prominent tuberosity, bounding a fossa of the ascending ramus on its external side. The inferior outline of the mandible follows the curve of the incisor tooth anteriorly to the middle of its length, when it reaches the line of the inferior border of the masseteric fossa. Here it commences another convexity, which is most prominent directly below the incisive tuberosity, and ascends again to the angle. The triturating surface of the molars is not oblique, as in E. planifrons, but is nearly horizontal. The enamel of the incisor is smooth, and has a well-marked bounding angle at the inner edge, and another within the external edge. Measurements. H. Length of inferior molar series 0082 Width of anterior face of inferior incisor 0028 Depth of ramus at M. ii 0090 Width of ramns below at M. ii 0052 Though this species is larger than any other species excepting the JE. planifrons, its interorbital width is the least. Its peculiar frontal groove is only approached by some specimens of the Pleurolicus sulcifrons. I have only two crania which undoubtedly belong to the jB. crassiramis, while a third very probably may be referred to it. Both the former have mandibles attached. John Day River, Oregon. 65 0 866 THE JOHN DAY FAUNA. PLEUROLICUS Cope. Paleontologioal Bulletin, No. 30, p. 3, Dec, 1878. Proceed. Amer. Philo. Soc.,.1878 (1879), p. 66. Family Saccomyidce. Superior molars rooted and short-crowned. The crowns with a lateral fissure bordered with an inflection of the enamel sheath, extending- to their bases. In the superior molars this inflection is on the external side, and does not divide the crown. Superior incisors not grooved. This genus is curiously near to the existing Heteromys and Perognathus, the two genera of Saccomyidce with rooted molars. The former differs in having: the molars divided into two columns, each of which is sheathed in enamel, while Perognathus only differs, so far as I am aware, in having the superior incisors grooved. It is also very nearly related to Entoptychus, and two of the species correspond in various respects with two of those of that genus. In view of the fact that most of the specimens of the P. sulcifrons are old individuals with well-worn molars, the idea occurred to me that the rooted character of the molars might be common to the species of Entoptychus, but that it might not appear until long use had worn away most of the crown, and the protrusion had ceased. Examination of the bases of the long molars of E. planifrons did not reveal any roots. It is also opposed to this view that the maxillary bone of the Pleurolici has little depth below the orbital fossa, appropriately to the short-rooted molars, while the depth is considerable in the typical Entoptychi, though there is a complete gradation in this respect. But I have demonstrated satisfactorily that PleuroUcus is a distinct genus by observations on the P. leptophrys. Some of my individuals of this species are young, with the crowns of the molars little worn; yet the roots diverge immediately on entering the alve- olus on all the molars. In the species of PleuroUcus the lateral fissure of the crown descends to its base, and hence persists longer than in the typical Entoptychi. I am acquainted with two species of this genus. The posterior part of the skull of an individual represents a third species, which I refer pro- visionally to this genus. MYOMORPHA. 867 The chai-cacters of the species are as follows: I. Otie and mastoid bullae continuous. Temporal ridges uniting into a sagittal crest; length of skull .043; supraorbital ridges and concave front P- sulcifrons. Temporal ridges not uniting; lengtk of skull .035; interorbital region flat; no ridges -P. leptophrys. II. Otic and mastoid bullie separated by a deep groove. Temporal ridges not united; front concave; size medium; supraoccipital wide -P. diplophysus. Pleurolicus sulcifrons Cope. Paleontological Bulletin, No. 30, p. 4. Proceedings American Philosophical Society, 1878 (1879), p. 66. Plate LXIV; fig. 6. Five crania represent this species in my collection; only one of these includes the posterior portions. In two of them the molar teeth are well worn; in one (the type) they present a medium degree of wear, and in two the roots only are preserved. This species resembles those of the allied genus Entoptychus in many respects. The superciliary borders are thickened upwards, forming two ridges, which inclose a groove between them which is more pronounced than in most specimens of the Entoptychus cavifrom. The muzzle is plane above and considerably wider than the interorbital space. The base of the malar is thin and oblique, and the foramen infraor- bitale exteritis is well in advance of the molar teeth and at the anterior part of the maxillary bone. A groove passes backwards from its inferior border, terminating in a small foramen which marks a point nearly half way to the first molar. This foramen is present in all the crania. Within this another shallow groove bounds the more prominent median line. The palatal sur- face exhibits two shallow lateral grooves, which commence opposite the posterior border of the first molar. The otic bullae are oval and not keeled, and have the usual bottle- neck. The mastoids are convex behind, and carry above an obtuse angle from the inion. The grinding surfaces of the molars are transverse ovals, only inter- rupted by the exterior fissure. The first molar is slightly different in form, being larger, and its section, when not much worn, being nearly round. Its 868 THE JOHN DAY FAUNA. anterior portion extends towards the alveolus, giving an anteroposterior oval on prolonged wear. Each tooth has three roots, one interior and two exterior; in the first they may be described as two posterior and one an- terior. The last molar is the smallest, the series exhibiting a regular gra- dation in size. Measurements. No. 1. M. Interorbital width 0050 Width of muzzle at middle 008O Depth of cranium at M. it 0138 Length of molar series along base 0080 Diameter of second molar f *°t^''°P°«*^"°^ '^^'^ ( I rausverse 0020 Width of face of superior incisor 0020 No. 2. Length of cranium fiom mastoid bulla to premaxillary, inclusive 043 Width of skull at mastoid bullie 021 Length of superior molar series on base 008 Width between bases of Pm. iv 0025 John Day River region of Oregon. Pleueolicus leptophrys Cope. Bulletin U. S. Geol. Survey Terrs., IV, p. 381. American Naturalist, 1883, p. 167, fig. 16 a, b. Plate LXIV; figs. 7-8. This species is in its typical form smaller than the last, and resembles in its size and its plane interorbital region the Entoptychus minor. Four more or less complete crania represent it, two of which are of young and two of old animals, as indicated by the degree of attrition of the molar teeth. In only two of them is the parietal region so preserved as to show the separate temporal ridges The interorbital region is flat and without superciliary ridges. The- diastema is just twice as long as the series of molar teeth. The auditory bulla is oval and not compressed or keeled, and the mastoid bulla is very convex posteriorly, and carries a very obtuse angle from the inion above. In young individuals the enamel inflection of the Pm. iv extends entirely across the crown. When the internal groove has disappeared on wear, the grinding surface is subround. With age the protuberance of the anterior root is reached, and the form of a horizontal section of the base is pyriform. The width of the front is two-thirds that of the muzzle. MYOMOEPHA. 869 Measurements. M. Length of skull, including mastoid bulla 0340 Length from front of premaxillary to Pm. iv 0145 Length of otic and mastoid bullae 0100 Interorbital width... 0050 Width of muzzle at middle 0080 Width between the Pm. iv s 0028 The exposure of the supraoccipital is wide and subquadrate, resembling only that of the Pleurolicus diplophysus among the rodents of this group. The temporal ridges converge gradually in a straight line posteriorly to the supi-aoccipital bone and then diverge without coming in contact. The John Day River of Oregon. Pleurolicus diplophvsus Cope. Bulletin U. S. Geol. Survey Terrs., IV, p. 381. American Naturalist, 1883, p. 167, fig. 16 c, d. Plate LXIV; fig. 9. A fragment of a skull which includes all posterior to the interorbital region is all that represents this species. The maxillary bones and teeth are lost. The interorbital region is concave, there being on each side a low angular ridge. These ridges continue into the temporal ridges, which have the same character as in the P. leptophnjs. They are straight and converge to the anterior part of the supraoccipital bone, where they do not come in contact, but diverge to end at the inion. The supraoccipital a triangle with obtuse apex and as wide as long. The tympanic tube is quite short, the shortest found in this group. The mastoid bulla is large, a little exceed- ing the otic, and has a general convex external face, which is not divided into two planes, an external and a posterior, by a sti'aight angle, as in most -of the allied species. There is a small portion homologous with the external face which turns inwards and passes under the squamosal, leaving a consider- able fissure-like foramen, which is wanting in most of the other species. The postsquamosal foramen is large, and the hammer-shaped bone very distinct, sending its posttympanic process to the meatus. The otic bulla is cut off from the mastoid by a deep oblique fissure. One end of the fissure is marked by the posttympanic process, and the other by the paroceipital. The bulla is -compressed and flattened on both inner and external sides. A strong ril » oon- 870 THE WHITE EIVEE FAUNA. nects the occipital condyle and the paroccipital process, c^ove which is the condyloid foramen. Measurements. M. Length from middle of supraorbital border to inion 018 Width of interorbital space 0055 Width between mastoid bulliB 0190 Width of occipital bone 0100 Width of foramen magnum 0050 Length of otic bulla alone 0100 This cranium is well preserved, and has been perfectly cleaned by weathering. It shows a good many points of difference, as compared with any of the other species of this group. It is to be regretted that the teeth are wanting. LAGOMORPHA. PAL^OLAGUS Leidy. Proceedings Academy Philada., 1856, p. 89; Extinct Mamm. Dakota and Nebraska, p. 33L — Cope, Ann. Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 477. 2 0 6 3 3 Family Leporidce. Dentition : I. ; C. -^ ; M. - ; or, Pm. - , M. -. Superior incisors sulcate, inferior incisors not sulcate. First and last supe- rior molars simple, intermediate ones with an enamel inflection of the inner side, which soon wears out First inferior molar of one more or less trans- versely divided column; other inferior molars consisting of two columns in antero-posterior relation. No postfrontal process. The above characters approximate nearly those of the existing genus Lepus. The only distinction between them signalized by Dr. Leidy is the more simple first inferior molar of the extinct genus, which consists of one column more or less divided. In Lepus this tooth consists of two columns, the anterior of which is grooved again on the external side in the known species. I am able to reinforce this distinction by a strong character, viz, the absence of the postfrontal process in Palceolaffus. As compared with the extinct genus Titanomys of Meyer,^ the difference is well marked, as that genus has the molar teeth f instead of |. The last inferior molar is cylin- ' Amphilagua. Catal. M^th. et Descr. Vertfebres Fosslles de la Basin de la Loire, 1853, p. 42. LAGOMOEPHA. 871 dric, consisting of but one column. The first inferior molar consists of two cylinders broadly united, as in the corresponding tooth of Palceolagus. As compared with Panolax Cope,^ which is only known from superior molar teeth, this genus may be at once recognized by the simplicity of the last tooth. In Panolax it consists of two columns. Dr. Leidy's descriptions and figures, which are available for the defini- tion of this genus, I'elate exclusively to the dentition. Characters drawn from the skeleton generally have been derived from my material and are now given. The nasal bones are wide, and the suture which separates them both from the frontal is concave forwards. The median frontal suture is persist- ent. The ascending portion of the premaxillary, which attains the frontal, is very narrow. The superior half of the facial plate of the maxillary bone is sharply rugose with reticulate ridges, but whether perforate or not I can- not certainly determine. The foramen infraorhitale is small and round, and issues below the reticulate portion of the maxillary. The otic bulla is com- pressed globular, with very thin walls. The meatus is large and has prom- inent lips, which open upwards. The mastoid is coossified with the bulla, and extends with a dense surface from behind to above and in front of the meatus. The incisive foramina are veiy large, enter the maxillary bones deeply, and are confluent posteriorly. The palate may be said to extend to the last molar, but there is a deep though narrow median poste- rior emargination. The distal extremity of the humerus is not so extended transversely as in Iscliyromys, and exhibits a moderate epicondyle. The inner flange of the condyles is well developed, and on the posterior face it is supplemented by a flange of the external edge of the condyles, which is as prominent or even more so, forming an intertrochlear crest. The arterial canal is inclosed by a slender bridge, and opens on the inner side above, and anteriorly below. In an ulna supposed to belong to this genus the coronoid process is elevated. The radial facet forms a narrow transverse plane, nearly divided by a wide anterior emargination. The shaft is compressed vertico-obliquely. A radius 'Report Lieut. G. M. Wheeler, 4to, IV, p. 296. 872 THE WHITE EIVEK FAUNA. exhibits a transversely oval humeral face of the head somewhat angulate at a superior and an infero-Iateral extremity, which are diagonally opposed to each other. Beyond the middle the shaft becomes wider, and is flattened obliquely. The peduncle of the ilium has a triangular section, the anterior face being the narrowest, and inclined at a little more than a right angle to the interior face. It expands but little at the sacral extremity, and the crest is very short. The external angle of the peduncle is very prominent and runs into the anterior extremity of the crest, from which proceeds also the more obtuse angle which is continuous with the pectineal line. A third longitudi- nal angle is seen on the middle of the external side of the sacral extremity, which is not continued on the peduncle. There is a prominent tuberosity on the median or first-described angle on the peduncle, which may or may not be homologous with the anterior inferior spine. There is no tuberosity on the inner bounding angle of the inner face as is seen in Gymnoptychus. The pubis leaves the ilium at right angles. Acetabulum nearly round. The femur has well developed great and little trochanters, and a third trochanter, which rises from the shaft in line with the inferior border of the little trochanter. The fossa of the great trochanter is well marked. The head is not separated from the great trochanter by a deep emargina- tion, and projects well within the internal face of the shaft. Its articular surface is prolonged towards the great trochanter. Fossa Ugamenti teris isolated. The distal extremity of the femur exhibits the superiorly pro- longed patellar groove characteristic of this group of rodents. The condyles are more than elsewhere produced downwards and posteriorly, and are well separated. The spine of the tibia is rudimental, and the crest is very obtuse. The inferior continuation of the latter forms a prominent reverted keel on the proximal front of the shaft, which is deeply concave on its inner side. The posterior face is also concave, and is separated by a laminar external bone from the external side. The external border of the head is not deeply notched as in Panolax. The fibula unites with the tibia on the proximal part of the latter. The remainder of the shaft is smooth. The external malleolus is large and at right angles to the long diameter of the distal end LAGOMOEPHA. 873 of the bone, and its extremity is a facet for contact with the calcaneum. On its external face is a prominent process directed backwards. The ex- ternal trochlear groove is deeper than the internal, and is well separated from it. The internal malleolus can scarcely be said to exist. It may be represented by a small process on the inner side of the extremity of the shaft. The astragalus is elongate and flat, and the trochlear portion is oblique. The neck is elongate, and convex on the inner side ; the constriction is on the inner side immediately behind the head. The long diameter of the latter makes an angle of 45° with the horizontal plane. The external troch- lear arc is much larger than the internal. The cotylus, which fits the ex- ternal condyle of the calcaneum, possesses a peculiar impressed area on its posterior surface. The calcaneum extends nearly as far anterior to its con- dyle as posterior. The free portion is subcylindric or subquadrate to the end. The internal process for the astragalus is quite jjrominent. The cuboid facet is directed obliquely inwards, running into a short longitudinal groove. The cuboid extremity is little depressed. The skeletal characters above enumerated were taken from the bones of P. turgidus and P. liaydeni, excepting in the cases of the ulna, radius, ilium, and calcaneum, which were derived from those of P. haydeni only. A cast of the cranial chamber of a specimen of Palceolagus haydeni dis- plays the superficial characters of the brain. As in the order generally, the hemispheres are small and are contracted anteriorly. The greater part of the cast of the cerebellum is lost, but enough remains to show that it was large. The olfactory lobes are large ; they are not gradually contracted to the hemispheres, but expand abruptly in front of them, being separated by a constriction only. They are wider than long, and than the anterior ex- tremity of the hemispheres. Their cribriform surface is wide, and extends backwards on the outer sides. Traces of the three longitudinal convolu- tions can be observed on the hemispheres above the lobus hippocampi. The internal and median are continuous at both extremities, and with the exter- nal to the base of the olfactory lobes. There is no definite indication of the Sylvian fissure. The lohus hippocampi protrudes laterally a little beyond the border of the external convolution. Its form is depressed. 874 THE WHITE RIVER FATHsTA. As compared with the brain of the rabbit {Lepus cuniculus) figured by Leuret and Gratiolet/ that of the Palceolagus haydeni is distinguished by the absolutely much smaller size of the hemispheres, and by the absolutely larger olfactory lobes, the excess being in transverse dimensions and not in the longitudinal. An important difference is also the absence of the median posterior production of the hemispheres seen in the rabbit, the pro- longation in the extinct species being lateral, and extending little behind the Idbus hippocanqn. The indications of the convolutions of the superior sur- face are similar in the two. As observed by Leidy, this genus presents the same number of teeth as in the existing rabbits, viz, I. - ; C.^; M. ^ ; and the difference con- sists in the fact that the first molar possesses two columns, while in Lejms there are three. Having collected a great number of remains of this genus, I am able to show that it is only in the immature state of the first molar that it exhibits a double column, and that in the fully adult animal it con- sists of a single column with a groove on its external face. The dentition undergoes other still more important changes with progressing age, so as to present the appearance of difference of species at different periods. These will be explained under the head of the P. haydeni, the most abundantly repi-esented in the collections. It may be mentioned here that in neither P. haydeni nor P. turgidus is there any evidence that more than two anterior molars are preceded by deciduous teeth. The latter are present in many specimens. Three species of this genus are known to have lived in Colorado during the White River epoch of the Miocene. Bones of two of the species have been found also in Dakota. The P. haydeni was probably the most abun- dant mammal of the fauna of that period. Depth of ramus at penultimate molar, 9°"" ; length of molar series, 10°"" ; no third lobe to molars P. haydeni. Depth of ramus at penultimate molars, 11"" ; length of tooth series, 14°"° ; a third posterior lobe of the molars P. triplex. Depth of ramus at penultimate molar, 12-14"» ; length of tooth series, 13-16"™ ; no third lobe P- turgidus. 'Anatomie Compar^e du Syst^me Nervenx, PI. Ill, Figs. 1, 2. LAGOMOBPHA. , 875 PALiEOLAGUS HAYDENI Leidj. Proceedings Academy Pbilada., 1856, p. 89. Extinct Mamm. Dakota and Nebraska, p. 331. Cope, Ann. Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 478. American Naturalist, 1883, p. 172. Palceo- lague agapelillua Cope. Paleontological Bulletin No. 15, p. 1 (Aug., 1873). Annual Report IT. S. Geol. Surv. Terrs., 1873 (1874), p. 478. Plate LXVI; figs. 1-27. The dentition of this rabbit has been fully described by Professor Leidy, but the material at the disposal of this distinguished naturalist did not enable him to furnish either the cranial or skeletal characters. My numerous specimens enable me to supply this deficiency. It is, however, to be ob- served that I cannot associate the skull with a skeleton as belonging to the same individual in any instance. The characteristic marks of the Leporidce. in all the bones of two species found mingled in profusion with the jaws and teeth of the P. haydeni and P. turgidus, in corresponding numbers, render their correlation sufficiently certain. The form of the muzzle seen from above is that of an obtusely trun- cated wedge. The contraction in the width of the nasal bones forward is very slight ; at the extremity they are strongly convex, while the posterior region is flat. The canthus rostralis is sharp, consisting of the narrow rib- like maxillary prolongation of the premaxillary bone, which at its anterior third is a little more elevated than the adjacent portion of the nasal bones. Its posterior apex does not extend quite so far posteriorly as that of the nasal bone, and the frontal sends a wedge-shaped prolongation to the outer side of it, which extends as a narrow splint anteriorly between the premaxillary and maxillary. The rugose patch of the maxillary extends more than half way towards the alveolar border of the superior incisors, and is bounded in front by the maxillo-premaxillary suture. It is separated from the orbit behind by a band of dense bone. The foramen infraorhitale exterius issues entirely below the rugose patch. The maxillo-premaxillary suture crosses the palate a little behind the middle point between the incisor and first molar, and on the side above the diastema bounds a long process forward. It then returns to the inferior border of the rugose patch, inclosing a notch with the inferior border of the same. The palatine bones are flat and occupy more than half the palate between the molars. Their common suture is at least as long as that of the maxillaries, and extends as far for- §76 THE WHITE EIVER FAUNA. ward as the posterior border of the second mohir. From this point the a,nterior suture extends to the posterior border of the third molar. The palatal notch is rectangular and is not wider than the palatine bone on each side of it. The last superior molar in this species is not grooved, has a round section, and is smaller than the first molar. The first is also small, and has a deep groove on its anterior face. Of the intermediate four molars the two median are the largest. The crowns of the molars, except the first, are without enamel on the external side, and in the last there is no enamel on the posterior side also. The inner side of the four intermediate molars is deeply grooved for a short distance, which gives a fissure-like notch on attri- tion. This disappears after use, as does also a less profound crescentic fossa in the middle of the crown, whose concavity is directed outwards. A line connecting the external borders of the molars is strongly convex; that con- necting the interior borders but slightly convex. The supex-ior incisors <3escribe a short arc, their triturating surfaces being directed exactly down- wards. The groove of their anterior face divides the latter equally. The inner division is more prominent than the outer. The mandible is contracted forwards, and the inferior outline rises gradually to the short symphysis. The symphyseal articular surface is oval. The ascending ramus rises abruptly opposite the middle of the last molar. Its anterior face at the base is nearly transverse, owing to the sharp prominence of the corresponding inner boi'der of the ascending ramus. In not one of my specimens is the angular portion of the jaw preserved. The condyle is subglobular in front, with a narrow posterior prolongation, as in the Lepus sylvaticus. The masseteric muscular insertion is flat and has a regularly convex anterior border, which does not extend beyond the line of the posterior border of the penultimate molar. There are two mental fora- mina, one on the middle of the depth of the ramus, below the fissure between the second and third molars ; and the other, marking the posterior third of the diastema, near its superior border. The pterygoid fossa of the ramus is deep, and its anterior border is well defined ; its anterior border is pierced opposite the middle of the vertical diameter of the ramus for the dental artery and nerve. The alveolus of the inferior incisor is marked by a Ion- LAGOMORPHA. 877 gitudinal convexity of the inner aspect of the ramus, which extends along- its inferior border as far as the fourth molar. A shallow groove separate* its posterior half from the inferior border of the ramus. The first and last inferior molars are smaller than the others. In the intermediate ones the posterior column is smaller than the anterior one, and is in close contact with it. Both are transverse oval in section, and the anterior is a little more prolonged inwards. The inferior incisor is rounded posteriorly, and narrowed ; in front the surface is very gently convex, and slightly oblique outwards. The enamel is smooth, folds over, forming a band on the outer side, and does not fold over on the inner side. The earliest dentition of this species known to me is the presence of the two deciduous molars, the first and second in position, before the appear- ance of any of the permanent series. Each of these has two roots, and the crown is composed of three lobes. In the first, the first lobe is a simple cusp; the two following are divided into two cusps each; the second is sim- ilar, excepting that the simple cusp is at the posterior end of the tooth. The grooves separating the lobes descend into the alveolus on the outer side, but stop above it on the inner. The measurements at this stage are — Measurements. M. Length of two milk-molars , O.OO.'iO' Depth of ramus at No. 2 '. 0042 Depth of ramus at diastema 0032 In the next stage the third permanent molar is projected, and has, like the second deciduous, a posterior simple column, whose section forms an odd cusp or lobe. The fourth true molar then follows, also with an odd fifth lobe behind. This lobed form of the molars is so ditferent from that of the adult as to have led me to describe it as indicating peculiar species under the name of Tricium avunculus and T. annce. In the next stage, the fifth small molar appears in view, and the second permanent molar lifts its milk-predecessor out of the way. In a very short time, the posterior, or odd, columns entirely disappear, sinking into the shaft, and the permanent molars assume the form characteristic of the species. The last stage prior to maturity sees the first milk-molar shed, and the younger portion of the first permanent molar protruded. A speci- 878 THE WHITE EIVER FAUNA. men of this age furnished the basis of the Palceolagus agapetillus. Its meas- urements are : Measurements. i£. Length of molar series 0100 Length of penultimate molar • 0020 Depth at penultimate molar 0070 Depth at first molar 0050 Transverse thickness at first molar 0037 There is the merest trace of a posterior lobe at this time, and that speedily disappears. The anterior lobe is subconical, and is entirely surrounded with enamel. By attrition, the two lobes are speedily joined by an isthmus, and for a time the tooth presents an 8-shaped section, which was supposed to be characteristic of the genus. Further protrusion brings to the surface the bottom of the groove of the inner side of the shaft, so that its section remains in adult age something like a B. The measurements of a medium-sized adult are — Measurements. it. Length from interorbital region to end of nasal bones (Spec. No. 1) 0.0250 Length of median suture nasal bones OICO Width at interorbital region 0080 Width between anterior borders of orbits 0180 Width at front of rugose patches 0110 Width of nasal bones at middle 0080 Width of nasal bones at extremity 0060 Width of anterior incisors together 0050 Width of posterior incisors together 0035 Width of incisive foramen at M. 1 0040 Width of palate at M.l 0075 Width of palate at M. 6 0080 Length of superior diastema •- 0120 Length of superior molar series 0110 Width of first molar 0020 Width of third molar 0033 Length of inferior molar series (Spec. No. 21 .012 Length from M. 1 to end of incisor 012 Length of diastema OOS Length of crown i f M. 1 0029 Elevation of crown of M. 1 above alveolus 0035 Depth .at M. 1 00/0 Depth atM. 5 0085 Inferior diameter of ramus below M.l 0040 The shaft of the humerus is subround at the middle. The external crest from the epicondyle extends by a long curve to the posterior side of the shaft where it ceases. The external extremity of the condyles is occupied for the LAGOMORPHA. 879 anterior half by a well-defined fossa. The g'eneral form of the ilium is slender. The ilioischiatic suture traverses a concave face behind the acetabulum. The rim of the latter is pronounced. The posterior face of the femur between the little and third trochanters is nearly plane ; it is strongly convex on the anterior face. The shaft below the middle is a transverse oval drawn to an obtuse angle at one extremity, on account of the upward prolongation of the angle defining the posterior face. The latter at its inferior part is divided by an obtuse longitudinal ridge which extends to the intercondylar fissure. The condyles exhibit about equal length and width, and their articulating surfaces are not distinctly cut off from that of the patellar groove. The external fossa; are very insignificant. The iimer cotylus of the head of the tibia is only about half as wide as the external. The spine, which limits it towards the middle line of the head, is separated by a wide interval from the inner margin of the external glenoid cavity. The external notch of the head, though small, is well-defined. Just above the point of attachment of the distal extremity of the fibula the tibia is triangular in section, the longest side being the inner. Half-way between this point and the distal extremity, the section of the shaft is a transverse oval. As we approach the extremity, two angular lines appear on the posterior face, near the borders, which extend, the one to the external border of the external mal- leolus, the other to the opposite border of the inner malleolus. Each incloses a narrow groove with the margins of the tibia, which terminate on each side of the distal extremity in a small backwardly directed process. The sur- face between these lateral ridges is gently concave. On the anterior face the border of the distal exti-emity is convex forwards. Above the extremity the face is concave, and near the inner border a little further up is a short groove-like fossa separated from the border by a little ridge. Both of these concavities are diflferently developed in different individuals, and arc some- times obsolete. Me€isurem€nts. M. Width of humerus at middle of shaft 0025 Width of humerus at condyles 0062 _. . iM. J i? J- < transverse 0050 Diameter of head of radius < . , „^^„ ( vertical 0028 Diameterof shaft of radius distally 0028 Length of ilium (proximally restored) 0190 880 THE WHITE RIVER FAUNA. M. Diameter of neck Of ilium J ''°*«^°P''«*''"°' ^^^ i exterointemal U0J5 LoDg diameter of acetabulum 0045 Anteroposterior diameter of ischium below Bpine OOJO Width of femur at proximal extremity 0090 Diameter of head I a"*''^"P°«t''»°^ 2]^. ( transverse 0U4o Transverse diameter at little trochanter 0065 Transverse diameter at third trochanter 0060 Transverse diameter at middle of shaft 0040 Transverse diameter at condyles 0070 Anteroposterior diameter at patellar ridge and condyles posteriorly 0080 Diameter of head of tibia 5 ^°*«™P°^**"'''- °^^? ( transverse moo Diameter of shaft of tibia transversely 0030 Diameter distal end of tibia ^'"^*«'-''P°«**''°^ JJ^?^ c transverse 0065 Length of astragalus 0070 Length of trochlea 0035 "Width of trochlea 0035 „, ,. ^. ., ( externallv - 0632 Elevation of trochlea < , • „ , I internally 0025 _. ^ „, 1 Uong 0030 Diameter of head < , " < short 0022 Length of calcaneum 0010 Length of heel of calcanenm 0045 Width at tibial facet 0045 Width at cuboid facet (transverse) 0035 Depth at cuboid facet 00;?2 It is very probable that this species is the progenitor of the Lepus syl- vaticus, which now inhabits North America in such abundance. It will then be interesting to trace the specific characters in which modification was necessary in order to effect the transition. Only the principal ones will be noticed; the few generic characters have already been pointed out. In the recent species the muzzle is similar in size; the premaxillary bones are more produced on the extremity. The perforations of the ante- rior part of the maxillary bone are larger and cover a greater extent of surface than in the Palosologus liaydeni. The posterior emargination of the palate is wider and deeper in Lepus sylvaticus. The otic bulla is a little larger in P. haydeni, and the mastoid bone is not spongy with perforations as in L. sylvaticus. Other parts of the skull cannot now be compared. The preserved portions of the mandibular rami of P. haydeni are of the same size as those of L. sylvaticus. The symphysis is shorter through the brevity of the inferior portion of the sutural sui-face in P. haydeni. The incisive LAGOMORPHA. 881 alveolar ridge is not distinguishable from the inferior border in L. sylvaticus. In the same species there is but one, the usual mental foramen, in the posi- tion of the anterior one of the extinct species. The spongy condition of the rami near the symphysis in the L. sylvaticus is not seen in the extinct species. Excepting the first tooth, the inferior molars are of similar size and constitution in the two species. It is probable that the Lepus ennisianus, described a few pages later in the present work, is the intermediate form in the line of descent between the Palceologus haydeni and the Lepus sylvaticus, or perhaps the L. aiiduboni. This species is from the John Day Miocene of Oregon, a later deposit than the true White River. The last inferior molar is like that of the P. haydeni, while the first molar is that of the genus Lepus. The postorbital process, though present, is smaller than in any existing Noith American species. The Palceologus haydeni was excessively abundant during the White River epoch in Dakota and Colorado, as the number of its remains indicate. I find, also, quite a number of maxillary and mandibular bones with teeth, in my Oregon collections, which I cannot distinguish from the present species. I have made the identification provisionally, in anticipation of the discovery of more perfect material. Pal^olagus triplex Cope. Paleontological Bulletin No. 16, p. 4. Annual Report IT. S. Geol. Surv. Terrs., 1873 (1874), p. 479. Plate LXVI; fig. 28. This rabbit is known from a single incomplete left mandibular ramus, which supports all the molar teeth in perfect preservation. It belonged to an adult animal, but the first inferior molar is but little worn, showing that the individual had but just attained maturity. This species is larger than the Palceolagus haydeni, and is equal in size to the P. turgidus. It difi'ers materially from both species in the constitution of its molar teeth. The first molar is peculiar in having an anterior as well as an external groove, the result being a trilobate instead of a bilobate sec- tion. This character would be maintained during the life of the animal, as the groove continues well into the alveolus. The four intermediate molars are characterized by the presence of a third column posterior to the second, and of smaller diameter. It is at first isolated from the second by enamel 56 c 882 THE WHITE KIVER FAUNA. investment, but on wearing becomes connected with it. They remain dis- tinct to an advanced age of the animal, since the grooves which bound them descend far into the alveoU before disappearing. Anotlier character- istic of the specimen at least, is seen in the intervention of a wide isthmus between the two principal lobes of each molar, or, in other words, of a naiTowed portion of the second column between its transverse portion and the anterior column. The result is that the triturating surfaces of the pos- terior column of the molar has a quadrilobate outline; one lobe anterior, one posterior, and two lateral. The tuberosity of the inner side of the ramus, which incloses the incisive alveolus, extends to below the second molar. Its surface, and a portion of that above it, is roughened with small punctifoi-m impressions. The external face of the ramus is smooth and somewhat convex anteropos- teriorly and vertically. The anterior border of the masseteric fossa is not prominent, as in P. turgidus, is regularly convex, and extends to the line of the posterior border of the penultimate molar. This species i*ests on characters which I have observed to be transi- tional in the P. haydeni, and I have attended to the possibility of the indi- vidual which has furnished them being a similarly immature P. turgidus. In a considerable number of specimens of the latter no approach to the present one is exhibited ; the latter is a fully-grown animal, and its characters would remain after long attrition of the teeth. Measurements. M. Length of molar series 016 Length of median three molars 010 Width of median molar 003 Depth of ramus at median molar Oil This species is rather larger than the prairie-marmot {Cynomys ludovi- cianus). Pal^olagus turgidus Cope. Paleontological Bulletin No. 16, p. 4. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 479. Tricium jyanierise Cope, Pal. Bulletin No. 16, p. 5. Plates LXVI, fig. 28; LXVII, figs. 13-27. This is the largest species of the genus, and after the P. haydeni the most abundantly represented in collections. At the locality which furnished LAGOMOEPHA. 883 several hundred specimens of the former species I obtained twenty of this one, inchiding both dental series and their supporting bones, and various portions of the skeleton, but no cranium. The maxillary bone displays the fossa below the anterior base of the zygomatic arch much better defined than in the P. haydeni. The palatine bone extends to the same distance forwards, that is, to opposite the anterior border of the third molar. The portion of the bone at the side of the pos- terior emargination is nan-ower, and not so horizontal as in the P. haydeni. The notch has the same extent, viz, to the line of the posterior border of the fourth molar. The superior molars are similar in general to those of the P. haydeni, but in none of them do I observe the fissure of the inner side of the crown. In several of them the median crescent persists, so that if the internal fissure exist at any time it must be speedily removed by attrition. In P. haydeni it remains after the disappearance of the crescent, as in that species there is no enamel on the external side of the crown. The mandible is more robust than in P. haydeni, but has much the same form. The anterior mental foramen is behind the middle of the diastema, on its superior aspect, and the posterior is below the second molar, below the middle of the ramus. The dental foramen is above the middle line of the ramus; the last-named two foramina having relations the reverse of that seen in P. haydeni. The anterior border of the masseteric fossa is ele- vated into a prominent rough ridge in most specimens, and reaches to the penultimate molar. The tuberosity inclosing the incisive alveolus does not extend so far posteriorly as in P. haydeni, ceasing below some part of the second molar, varying a little in different individuals; its surface is covered with impressed punctse. The anterior border of the pterygoid fossa of the ramus is not well defined. There is no groove on the inner side of the first molar. The two col- umns of the three intermediate molars are closely appressed, and the second is lower, not so wide, but a little longer anteroposteriorly than the anterior colvimn. The last molar is deeply grooved on the inner side; its grinding face is only half as large as that of the first molar. The inferior incisor is not deeper than wide, and is obtuse behind. The anterior face is nearly 884 THE WHITE EIVER FAUNA. plane, and the enamel is marked by numerous approximated, faint trans- verse undulations in well preserved specimens. Measurements. No. 1. u. Length of superior molar series 016O Length of seoond molar 0025 Width of secoud molar 0043 Length of fourth molar 003O Width of fourth molar 00r>5 No. 2. Length of molars 0.016 Length of three median molars 010 Depth of ramus at central molars Oil Width of central tooth 0035 No. 3. Depth of ramus at penultimate molar 0130 The deciduous molars present much the same character as in P. haydeni, except that there is scarcely a trace of the odd j^osterior tubercle on the second. The posterior root of the latter extends to the bottom of the alveolus. The grooves of crown do not descend to the alveolus on either side. Measurements of such a specimen are — Meas^irements. M. Length of two anterior molars 0.0068 Length of tirst molar 0032 Width of first molar 0021 Depth of ramus at first molar 0085 Depth of ramus at diastema 0061 I have of this species portions of humeri, femora, tibiae, and astragalus. They resemble very much the corresponding elements of the P. haydeni, but differ strikingly in the much larger size. The distal extremity of the humerus has a greater transverse extent than that of the P. haydeni, chiefly because of the greater size of the internal epicondjde. The external trochlea of the condyles extends also a little fur- ther outwards beyond the external posterior trochlear flange. The corre- sponding internal flange is not nearly so prominent as in P. haydeni. The olecranar fossa is scarcely perforate ; the coronoid fossa is shallow. The external marginal acute edge is prolonged well upwards. The proximal portion of the femur has the characters of that of P. haydeni, but the third LAGOMOEPHA. 885 trochanter is smaller, and its apex is the end of the truncate external sur- face of the great trochanter. In P. haydeni the two are connected by a thin edge. The great trochanter projects considerably beyond the head, and the little trochanter is very prominent, and is directed posteriorly. The condyles of the femur are not produced so far backwards as in P. haydeni. In all the particulars which I have described as characterizing the distal extremity of the tibia of P. haydeni, P. turgidus agrees with it, differing only in size. The same may be said of the astragalus, excepting that the inner trochlear ridge is a little less reduced in the P. turgidus. Measurements. II. Diameter of distal end of humerus^ anteroposterior, least 004 t transverse 012 "Width of proximal end of femur 013 Diameter of head ^'*°*''""P''»t''"°'" ^ ( transverse .0065 Width of femur at little trochanter 008 Width of femur at third trochanter 007 Width of femur below third trochanter 005 Width of condyles of femur 010 Depth of same at posterior margin 010 Diameter of shaft of tibial ''"t'^^P''^*''""'^ ^^* i t ranaverse 005 Diameter of distal end of tibia ^ ' vvMt < transverse 0110 Length of astragalus 0110 Length of trochlea 0056 Width of trochlea 0060 Elevation l"f«*''"^^l"'^g« O^^^ ( of internal ridge 0040 Diameter of head P°°g "O^O ( short 0033 White River beds of Dakota, and of Northeast Colorado. LEPUS Linn. 10 ^ ^ Dental formula: I. :r ; C. - ; Pm. - ; M. -. First superior molar sim- 1 (J 2 n ,ple; first inferior molar with two external grooves; last inferior molars consisting of two cylinders. Postorbital processes present. I am acquainted with but one extinct species of this genus, and this is from the John Day or Middle Miocene period. It proves the ancient origin 886 THE JOHN DAY FAUNA. of this genus, now so widely distributed over the earth. Species of Lepus are reported by Gervais from the Miocene (Montabuzard) and PHocene (Montpelier) of France. Lepus ennisianus Cope. Bulletin U. S. Geol. Snrv. Terrs., IV, 1881, p. 385. American Naturalist, 1883, p. 174, fig. 21. Plate LXVI, page 29. This species is abundant in the Miocene beds of the John Day River, Oregon, associated with a species which I cannot distinguish from the Palaeo- lagus liaydeni. The Lefiis ennisianus exceeds the last-named species in dimen- sions, being intermediate between it and the Palaeolagus turgidus. The form of the skull and character of the postorbital processes refer this species to the neighborhood of the Lepus auduboni and L. hachmani} The former has the general outline of that of Lepus sylvaficus, with which it nearly agrees in size. The postorbital processes are free and shorter and narrower than those of the L. auduhoni. The supraorbital notch is insig- nificant, and is not bounded by either an angle of the border or a process. Behind the postorbital processes the cranium is narrower. The parietal region is convex in both directions. The interorbital and base of the nasal region are flat The middle of the superior part of the occipital projects table-like beyond the lateral portions, as in recent rabbits. The otic bulla is large and is flattened on the external side. The mastoid presents some subvertical grooves. The paroccipital process is rather short and is tumed backwards at the apex. The mandible has much the form of that of L. sylvaticus, with certain diff"erences. A slight convexity of the anterior border of the ascending ramus is the only trace of coronoid process. The posterior border of the same projects very little behind the condyle, and is but slightly concave below that point. The inferior border of the masseteric fossa' terminates below the anterior border of the base of the coronoid process, which is posterior to the corresponding position in L. sylvaticus. Here the masset- eric fossa extends as far forwards as the line of the posterior part of the fourth inferior molar. 'See Baird, Miimmalia of the V. S., Pac. R. R. Surveys, VIII, p. 574. LAGOMOEPHA. 887 The superior molras have the form usual in this genus. The crowns are grooved on both the external and internal faces. The first has less transverse extent than the others (except the sixth), and has a shallow groove on the anterior face. The sixth molar is a small and simple cylin- der. Of the inferior molars, the first has the greatest anteroposterior diameter, while the transverse is equal to that of the others. Of its external grooves the posterior is the strongest. The last molar is much the smallest, and its section is a figure 8, with the wider circle next to the fourth molar. The anterior column of the other molars wears so as to be higher than the posterior. Its inner edge carries a shallow groove, while the external edge is narrow and smooth, and their alveoli terminate in a swelling below the first molar (Pm. III). The groove of the superior incisors is nearer the internal than the external side. The inferior incisors are perfectly flat. Measurements. M. Length of skull from inion to above Pm. II 048 Length from inion to base of postorbital process (axial) 032 Width of skull at glenoid cavities 020 Width of skull behind bases of postorbital processes 009 Vertical diameter of orbit 0125 Depth of skull and mandible in place, at middle of orbit 0310 Depth of mandible at condyle 0310 Length of mandible to exit of incisor 044 Depth of mandible at last molar Oil Depth of mandible at middle of diastema 005 Length of superior molar series 012 Width of Pm. II (above) 002 Width of M. I : 003 Length of inferior molar series 013 Length of inferior Pm. Ill 003 A fragmentary skeleton is associated with jaws and teeth of this spe- cies, and they are presumably parts of the same animal. They resemble the corresponding parts of Lepus sylvaticus, but are relatively smaller. The centrum of a lumbar vertebra is much depressed. There is a prominent anterior inferior spine of the ilium. On the internal side of the distal end of the tibia the ligamentous groove is more, and its bounding process is less, distinct than in L. sylvaticus. Measurements. M. Width of centrum of lumbar vertebra 0083 Depth of centrum of himbar vertebra 0040 888 THE JOHN DAY EPOCH. Diameter of acetabulum 0060 Diameters of head of tibia} ^° ^ " „,„, ( transverse UlUb Diameter of distal end of tibia 5 ™t«roposterior 0046 ( transverse uu» Length of free part of calcaneum - 007 From the John Day River and the north fork of the John Day River, Oregon. C. H. Sternberg. This rabbit ia the oldest species which can be referred to the genus Lepus. It is dedicated to my friend Prof Jacob Ennis, of Philadelphia, the distinguished mathematician and physicist. CARNIVORA. This order embraces the clawed mammalia with transverse glenoid cavity of the squamosal bone, confluent scaphoid and lunar bones of the carpus, and well developed cerebral hemispheres. It is well distinguished from all others at present known, but such definition is likely to be invali- dated by future discovery. Some of the Insectivora possess a united sca- pholunar bone, but the reduction of the cerebral hemispheres of such forms distinguishes them. The presence of the crucial fissure of the hemispheres is present under various modifications in all Carnivora, except one or two of the Melince (Garrod), while the parieto-occipital and calcarine fissures are absent. The many types of existing Carnivora fall into natural groups, which are of the grade termed family in zoology. But the distinction of these from each other is not easily accomplished, nor is it easy to express their relations in a satisfactory manner. The primary suborders of pinnipedia and fissipedia ax-e easily defined. Various characters have been considered in ascertaining the taxonomy of the more numerous fissiped division. The characters of the teeth, especially the sectoa-ials, are important, as is also the number of the digits. Turner^ has added important characters derived from the foramina at the base of the skull, and the otic bulla, which Flower^ 'Proceedings Zoological Soc, London, 1848, p. 63. 2 Loo. cit., 1869, p. 5. CAKNIVORA. 889 has extended. Garrod^ has pointed out the significance of the number of convolutions of the middle and posterior part of the hemispheres. I have added some characters derived from the foramina of the posterior and lateral walls of the skull.- Mr. Turner also defines the families by the form and relations of the paroccipital process. In studying the extinct Carnivora of the Tertiary period it has become necessary to examine into the above definitions, in order to determine the affinities of the numerous genera which have been discovered. To take them up in order, I begin with the foramina at the base of the skull. The result of my study of these has been that their importance was not over- rated by Mr. Turner, and that the divisions of secondary rank indicated by them are well founded. Secondly, as to the form and structure of the auditory bulla. Although the degree and form of inflation are characteristic of various groups of Carnivora, they cannot be used in a systematic sense, because, like all characters of proportion merely, there is no way of express- ing them in a tangible form. For, if the forms in question pass into each other, the gradations are insensible, and not sensible, as is the case with an organ composed of distinct parts. The same objection does not apply so much to the arrangement of the septa of the bulla. The septum is absent in the Arctoidea of Flower {Ursidce of Turner), small in the Cynoidea (Flower, Canidce Turner), and generally large in the ^luroidea (Flower, FelidcB Turner). But here occurs the serious discrepancy, that in the Hysenidge, otherwise so nearly allied to the Felidse, the septum of the bulla is wanting. Nevertheless, the serial arrangement of the order indicated by Flower, viz, commencing with the Arctoidea, following with the Cynoidea, and ending with the ^Eluroidea, is generally sustained by the structure of the auditory bulla, and by the characters of the feet and dentition, as well as of the cranial foramiua. Turner's arrangement in the order Ursidse, Felidae, and Canidse is not sustained by his own charactei-s, and its only support is derived from Flower's observations on the external or sylvian convolution of the hemisphere of the brain.^ There are three simple longi- ' Proceedings Zool. Soc, London, 1878, p. 377. *Proceediug8 Amer. Philosophical Society, 1830. "Proceedings Zoological Society, London, 1869, p. 482. 890 THE MIOCENE FAUNA. tudinal convolutions in the raccoons; in the civets and cats the inferior convohition is fissured at the extremities, while in the dogs it is entirely divided, so that there are four longitudinal convolutions between the sylvian and median fissures. An important set of characters hitherto overlooked confirms Flower's order. I refer to those derived from the turbinal bones. In the ursine and canine forms generally the maxilloturbinal is largely developed, and ex- cludes the two ethmoturbinals from the anterior nareal ojDening. In the Feline group, as arranged by Turner, the inferior ethmoturbinal is devel- oped at the expense of the maxilloturbinal, and occupies a part of the anterior nareal opening. These modifications are not, so far as my expe- rience has gone, subject to the exceptions seen in the development of the otic septa and molar teeth, while they coincide with their indications. The seals possess the character of the inferior group, or Ursidas, in a high degree. The characters derived from the paroccipital process are of limited application, as the study of the extinct forms shows. In view of these facts, I have proposed the following arrangement:^ Mr. Wortman has suggested that the Arctoidea should be distinguished as a primary division, since it diff'ers from the Cynoidea in the articulation of the astragalus with the cuboid bone. I do not, however, find this character to be constant in the Arctoid series. It gradually disappears in the Mus- telidse, and is wanting in 3fustela pennaniii and Procyon nasiia. External nostril occupied by the complex maxilloturbinal bone; ethmoturbinals con- fined to the posterior part of the nasal fossa; the inferior ethmoturbinal of reduced size Hypomycteri. External nostril occupied by the inferior ethmoturbinal and the reduced maxillo- turbinal Epimycteri. While no doubt transitional forms will be discovered, the types at present known fall very distinctly into one or the other of these divisions. The characters are readily perceived on looking into the nares of well- cleaned specimens. The Hypomycteri stand next to the Pinnipedia, since the maxilloturbinal bone has the same anterior development in that group. In searching for definitions of the families, it is necessary to be precise 'Proceedings Ajnerican Philosophical Society, 1882, p. 471, where a list of the genera is given. CARNIVORA. 891 as to the definition of terms. The meaning of the word sectorial is in this connection important, since there are so many transitional forms between the sectorial and tubercular tooth. A sectorial tooth, then, of the upper jaw is one which has at least two external tubercles, which are the homologues of the median and posterior lobes of the sectorial of the cat. By the flat- tening and emargiuation of their continuous edges, the sectorial blade is formed.^ One or two interior and an anterior lobe may or may not exist. In the genera of the Procyonidce, except in Bassaris, the two external tubercles do not form a blade. The inferior sectorial tooth differs from the tubercular only in having an anterior lobe or cusp, which belongs prim- itively to the interior side. The inferior sectorial teeth with large heels, as in Vivei'ridse and Canidte, I have called tubercular sectorials. The secto- rial blade is formed by the union and emargination of the edges of the an- terior and the principal external cusp. This blade is not well developed in the genus Cynogale and still less in the Procyonidce and Ursidce. In looking for causes in explanation of the modifications of structure cited, one can easily discover that there is a close relation between the arrangement of the teeth and the mechanical laws involved in the perform- ance of their function, that of seizing an active prey and of cutting up their carcasses into pieces suitable for swallowing. It is obvious that in the lat- ter case the flesh-teeth bear the resistance, and the masseter muscle is the power, and that the nearer these parts are together the better is the function performed. As a matter of fact, the sectorial teeth in modern Carnivora are placed exactly at the angle of the mouth, which is nearly the front border of the masseter muscle. Both the muscle and the teeth have, however, moved forwards in con- nection with the shortening of the jaw behind. This has been due to the necessity of bringing the power (masseter) nearer to another point of resist- ance, viz, the canine teeth. In the early carnivores (as Hycenodontidce) the long jaws supported more numerous teeth (^) than in any modern families, and the fissure of the mouth was probably very wide. The canine teeth were evidently very ineffective weapons. The animals probably only snapped with their jaws, and did not attempt to lacerate or hold on, as do 'See "On the origin of the specialized teeth of the Carnivora," American Naturalist, 1879, p. 171. S92 THE MIOCENE FATJNA. the cats. The dogs of to-day are long-jawed, and they snap in a manner quite distinct from anything seen among the cats. The only dogs that hold on are the short -jawed bulldogs. So in the use of the canines, we have the ground of the shortening of the jaw behind and before, and the consequent change of structure, which resulted in the modern perfected Felidce. The families are then defined as follows: Htpomycteri. I. No sectorial teeth in either jaw. Toes 5-5 Cercoleptid(B. II. Sectorial teeth in both jaws. a. Toes 5-5. ;9. No alisphenoid canal. True molars f Procyonidw. True molars i Mustelidw. /S/9. Au alisphenoid canal. JVIolars quadrate, | Aeluridw. Molars longitudinal, f Ursidw. aa. Toes 5-4 or 4-4. •Sectorials well developed, an alisphenoid canal Canidw. Epimycteei. I. Molars l)aplodont. Toes 5-4; no alisphenoid canal Protelidce. II. Molars bunodont, no sectorials. Toes 5-5; an alisphenoid canal Arctictidm. III. Molars bunodont, with sectorials, a. Otic bulla with septum. [i. Alisphenoid canal and postglenoid foramen, present. y. True molars well developed. Toes 5-5 Viverridce. Toes 5-4 Cynictidce. Toes 4-4 , - Surkatidce. yy. True molars much reduced. Toes 5-5 CryjJtoproctidw. Toes 5-4 NimravidcB. /5,?. No alisphenoid canal; postglenoid foramen rudimeutal or wanting. Toes 5-4 Felidce. aa. Otic bulla without septum. No alisphenoid caual, nor postglenoid foramen. Toes 4-4 HycenidcB, CANID^. 893 Fig. 33. — Nimravtu gomphodus, two-fifths natural size. Mus. Cope. CANIDaE. Species of this family were very abundant during the Miocene period in North America as in Europe. Tliose of the Lower and Middle Miocene epochs belong to genera allied to, but distinct from, Canis ; while those of the Upper Miocene (Loup Fork) and later horizons pertain to the latter genus, with a few exceptions. The characters of the Miocene genera are as follows : I. Molar formula f |. Humerus with epitrocblear foramen AmpMcyon. II. Molar formula ^ f. a. Xo anterior lobe of sujierior sectorial. Humerus with epitrochlear fdramen. Inferior sectorial heel trenchant Temnocyon. Inferior sectorial heel basin-shaped Galecymts. Humerus witliout epitrochlear foramen. Inferior sectorial heel basin-shaped Canis. aa. An anterior lobe of superior sectorial. Heel of lower molar not trenchant ; no epitrochlear foramen JFAurodon. HI. Molar formula f r|. Heel of inferior sectorial trenchant Euhydrocyon. IV. 3Iolar formula I i. Heel of inferior sectorial basin-shaped Oligohiinis. V. Molar formula | f. First inferior molar two-rooted Hytenocyon. To the^e genera 1 refer twenty-five species of the American Miocenes. 894 THE WHITE RIVER FAUNA. AMPHICYON Lartet. Bulletin Soci6t€ G^ologique de la France, 1836, vii, 217-220; Blainville, Comptes-Rendus, 1837, v, 434; L'Institut, 1837, v, 18-19; Blainville, Osteographie, ix, Subursus, 78-96. 3 1 4 3 Dental formula: I. ^^ : G. ^-j Pm. -; M. -. The true molars of the o 1 4 o superior series all tubercular; the last two of the inferior series also tuber- cular. First inferior true molar a sectorial, with an internal tubercle and a heel with a superior groove, bounded by raised borders. Humerus with an epi trochlear arterial foramen. Much is yet to be desired in the elucidation of the characters of this genus, especially of the American forms, which are less abundant and of smaller size than those of Europe. The typical species, Amphicyon major Blv., was the largest, equaling a bear in size. It is derived from the Mio- cene of Sansan, and a smaller form of it is found, according to Pomel, at San Gerand-le-Puy. Other species are derived from the latter locality, and all are typical of the Miocene formation in Europe. In the "Mio-pliocene" of India a single species has been discovered, the A. palceindicus of Lydek- ker. Three species occur in the Lower and Middle Miocene of North America, the largest of which about equals the wolf in size. On account of the large development of the inferior tubercular teeth, I have suspected that the Canis ursinus Cope, from the Loup Fork group of New Mexico, would prove to be an Amphicyon. If so, it is the only representative of this genus in our Upper Miocene. The three American species differ as follows: The A. cuspigerus is small, not exceeding the kit-fox in dimensions. The A. hartshornianus is about the size of a coyote, and has rather smaller tubercular molars, especially of the lower series. The A. vetus is a little larger, but has the tubercular mo- lars disproportionately larger than those of the A. hartshornianus. Amphicyon vetus Leidy. Daphwnus vetm Leidy, Proceed. Academy Philada., 1853, 393. Amphicyon vetus Leidy, 1. c, 1854, 157, 1857, 90. Extinct Mammalia Nebraska, Dakota, 1869, p. Z'ipartivi. Plate I, figs. 1, 2, and 5. Dr. Leidy's descriptions last cited above, with the accompanying fig- ures, cover two species, a larger and a smaller, the latter being the A. harts- hornianus. Of the true A. vetus my collection includes a fragmentary skull CANID^. 895 with several teeth of both jaws. They indicate a canine animal of about the size of the Temnocyon wallovianns ; that is, with a skull intermediate in dimensions between those of the wolf and coyote. The superior sectorial tooth is as long as that of the Temnocyon altige- nis, but not so thick, and with narrower blade. The anterior base of the crown is concavely emarginate. The second tubercular is more like the first of Temnocyon corypJiceus than that of T. aUigenis, but may be readily distinguished by the insignificance of the two external tubercles. The crown is not excavated, and it is travei'sed across the middle by a regularly curved low ridge, which represents the V-shaped crest of most modern dogs. The internal cingulum is wide and regularly convex. The external cingu- lum is prominent forwards and outwards, as in T. coryphceus, but is obsolete at the base of the second external tubercle. The crowns of the third and fourth inferior premolars are preserved in a somewhat damaged state. The fourth has a posterior lobe of the border. The sectorial has lost its anterior cusp. It is rather small, and the internal tubercle is well developed, though not so high as in Amphicyon cuspigerus. The keel of the heel is not much elevated and is external to the middle line. There is a low inner basal cingulum, readily worn away. The first tuber- cular is a large tooth, nearly equal to that of T. altigenis, and therefore rel- atively much exceeding that of A. hartshornianus and of T coryphceus. It has two opposite tubercles in front of the luiddle, and one external to the middle posteriorly, and no external cingulum. The alveolus of the second tubercular shows that it also was a large tooth. Measurements. M. Diameter of crown of superior cauine Oil Diameters of superior sectorial } "'^ *''°P°^ ^"*" ' ( transverse m trout 009 Diameters of second superior tubercular 5 P V'" C transverse at middle 007 Length of inferior Pm. iii iv on base 022 Length of heel of sectorial 00.5 Diameters of first inferior tubercular^ anteroposterior 0006 C transverse 0066 Length of alveolus of second tubercular 004 The specimen above described agrees very nearly with the larger of those described by Leidy, and represented by his Plate I, figs. 1-2, of the 896 THE WHITE KIVER FAUNA. extinct Mammalia of Dakota and Nebraska. It differs from all the speci- mens of A. hartshornianus, in the disproportionately larger size of the tuber- cular molars both above and below, and by the tendency of the heel of the inferior sectorial to form a median keel. I found the fragments lying close together without intermixture of other species, on an exposure of the White River beds in Eastern Colorado, at the same locality which furnished the specimens of A. hartshornianus. Amphicyon hartshornianus Cope. Bulletin U. S. Geol. Survey Terrs., vi, p. 178. Cania hartshornianus Cope, Synopsis of New Vertebrata of Colorado, Misc. pub. U. S. Geol. Surv. Terrs., 1873, p. 9. Annual Report U. S. Geol. Surv Terrs., 1873 (1874), p. 505. Plate LXVIIo; fig. 4. This was the most abundant species of the genus during the White River epoch proper. It was originally established on a specimen from Eastern Colorado, and I have subsequently obtained other specimens from the same locality. On an examination of the specimens obtained by Dr. Hayden in the Bad Lands of Dakota, now in the museum of the Philadel- phia Academy, I find parts of four skulls, two of which have been figured by Dr. Leidy on his Plate I, figs. 3, 4, and 6, and referred to in the text as belonging to the A. vetus. I have also part of a skull with nearly complete superior dentition from the John Day Valley of Oregon, which I cannot distinguish from this species. The original specimen consists of a portion of the mandibular ramus with the first tubercular molar and alveolus of the second. The species was nearly as large as the Canis latrans. The anterior molar preserved has an interrupted cingulum on the outer side, which projects considerably in front, thus interrupting the parallelogrammic outline of the crown. The outer anterior tubercle is much the larger, while the inner ones are both obsolete. In Galecynus gregarius Cope the tubercles are equal, and there is no cingu- lum. Root of tubercular molar subround in section, as in G. gregarius. Measuremenis. M. Length of bases of M. ii and iii 0130 Length of base of crown of M. ii 0090 Width of base of crown ofM. ii 0060 Elevation of crown of M. ii 0050 CAi^iD^. 897 A second specimen, which is from the same locality as the last, in Eastern Colorado, consists of the skull anterior to the orbits and the poste- rior nares, lacking the superior walls. The teeth are all pi-esent, excepting one first premolar and five incisors. The form is short and wide, the malar bones much expanded and the muzzle narrowed. The size of the teeth is about that of the Temnocyon coryphceus, but the posteriorly-expanded out- line is like that of the T. josephi. The sectorial is a little smaller than that of the A. vetus from the same locality ; but the principal diff'erence becomes apparent on comparing the tubercular molars. The second of the A. harts- Jiornianus has not more than half the surface area of that of the A. vetus. The external incisor is short and rather stout ; the canines are long, curved, and acute, and with convex inner side ; the inner cutting ridge is faint, the posterior moderately distinct. They are much more slender than in the T. coryphaeus. There is a diastema behind the canine equal to the long diameter of its alveolus. The first premolar has a long base and a short anteriorly-placed apex ; it is followed by u space equal to its long diameter. The second premolar is low and is prolonged backwards at the base ; it is followed by a short space. The second premolar is more sym- metrical, but has no distinct basal tubercles ; there is a faint trace of a posterior median tubercle. This tooth will distinguish the species from Temnocyon coryphceus if other parts are wanting The sectorial is small for the size x)f the tuberculars ; its inner anterior tubercle is well developed. The first tubercular has a well-developed external basal cingulum. The two external cusps are low; the space between them and the inner border is nearly equally divided by a low V- shaped ridge. This character will dis- tinguish this tooth from those of Temnocyon altigenis and T. wallovianns. The second tubercular is much smaller and stands much within the external border of the sectorial. Its external border is very oblique, more so than that of the first. It resembles the latter in details, the points being less pronounced ; and the external cingulum is obsolete. The third tubercular is opposite the inner half of the second, and its surface area is very small, rather less than that of the base of the first premolar. It is supported on a projection of the maxillary bone, which is separated from the base of the pterygoid process of the palatine by a deep notch. The posterior nareal 57 c 898 THE JOHN DAT FAUNA. orifice is rather narrow and its border presents a median point posteriorly, which separates two deep concavities, about as in T. coryphaeus. Measurements of palate, etc. M. Length from premasillary border to nares 072 Width of dental series, including canines 0G5 Length of canine tooth 020 Long diameter of canine at base U07 Li'iigth of premolar series >. 0:l9 Length of sectorial — 013 Width of sectorial in front 008 Elevation of sectorial in front 008 T-,. . J- j; i i 1 1 5 anteroposterior 010 Diameters of first tubercular i ' transverse 014 Diameters of second tubercular \ ^ < transverse 009 ■Width between bases of canines 017 Width between sectorials posteriorly 041 Width between third tuberculars 023 Width of nares 012 The third or Oregon specimen agrees closely with the one just de- scribed. The crowns of its superior incisors are preserved, so that it can be seen that they are obspatulate with angular extremities, and are not notched, as in Galecynus geismarianus and various living species. The best ascertained characters of this species, then, as compared with the A vetits, are (1) the much smaller tubercular molars in both jaws ; (2) the strongly double tubercular character of the heel of the inferior sectorial as compared with the tendency to a single keel seen in the A. vetiis. Dedicated to my friend Prof. Henry Hartshorne, formerly of Haverford College, Pennsylvania. Amphicyon cuspigerus Cope. Bulletin U. S. Geol. Survey Terrs., vi, p. 178. Canis cuspigerus Cope, Paleoutological Bulletin No. 30, p. 8, December 3, 1878. Proceedings American Philosoph. Society, 1878, p. 70. Amphicyon entoptychi Cope, Paleoutological Bulletin No. 31, p. 3, December 24, 1879. Proceedings Amer. Philosoph. Soc, 1879, i>. 372. Plate LXVIII; figs. 1-4. This species is considerably smaller than the A. hartshorniamis, and intermediate in size between the Galecyni geismarianus and gregarius. It is represented in my collection by two crania, one nearly perfect and with the mandible attached ; the other with its superior portions crushed and with- out incisive region or lower jaw. CANID^. 899 The cranium is elongate, and the muzzle is not shortened, but is rather compressed. There are no true postorbital processes, but merely obtuse angles, from which obsolete temporal ridges converge backwards. They do not unite early, as in the Galecynus geismariamts, Amphicyon vetus, &c., but only combine to form a low sagittal keel near the middle of the parietal bone. The brain-case is rather large, and is moderately contracted beliind the orbits, more than in Vuljjes cinereoargentatus or Canis latrans and C. can- crivorus. The occipital surface is strongly convex to fit the vermis of the cerebellum. The otic bulla is small and has no t^mipanic prolongation. This character will distinguish the species from the G. geismarianus, where the bullae are very large. The paroccipital process is short and obtuse, and is well removed from the bulla, not being even connected with it by a ridge, as in recent dogs. The posttympanic process is short and obtuse. The postglenoids are well separated from them, and have a greater transverse extent than in i-ecent dogs. They are not overlapped posteriorly by any part of the otic bullse. The basioccipital is wide and is marked by a shal- low fossa on each side opposite each paroccipital process. This is wanting in the G. geismarianus and the G. gregarius. Between the bulliB the surface is not keeled, but is flat and slightly concave. The mandibular rami are shallow, and their inferior margin is not stout. A o^entle elevation of the latter commences below the first tubercular tooth, and the alveolar border rises but little behind. The masseteric fossa is deep and well defined. Sutures. — The ascending branch of the premaxillary is very narrow and elongate, but fails by a little to reach the narrow acute anterior prolonga- tion of the frontal. The nasal bones are quite narrow, and their apices are above the anterior third of the orbit. The fronto-maxillary suture is strongly arched upwards. The parietal bones extend further forwards laterally than on the superior surface of the skull, where their anterior outline is broadly truncate. Below they are extensively in contact with the alisphenoid bone. The squamosal is low and elongate. Foramina. — The nares are rather small, and the vertical exceeds the transverse diameter. The opening of the infraorbital foramen is above the anterior part of the superior sectorial tooth. There is no postparietal 900 THE JOHN DAY FAUNA. foramen, bur a small mastoid is visible. The foramen magnum is large and is subround through its extension interiorly ; its border is notched at the supe- rior base of the condyle. The condylar foramen is small and is near the/ lacerum posterius, but entirely distinct from it. The latter is subround and rather large. There is no distinct/ carotideum visible. The/ lacerum ante- rius is much contracted. The/ ovale is rather large and transverse, and the / alisphenoidale posterius is small and distinct. Foramen postglenoidale rather large. Dentition — The third premolar tooth in both jaws differs from the cor- res^Donding one in the C. gregarius and in most recent species, in lacking the lobe of the posterior cutting edge, agreeing in this (as regards the inferior series) with the Temnocyon altigenis. It is present in the fourth inferior pre- molar, which has besides, a low heel. The inferior sectorial tooth is char- acterized by its great robustness ; the internal median tubercle is much elevated, while the principal cusp is short. The heel is wide and basin- shaped, with the inner border as much elevated as the outer. The first tubercular molar is characterized by its width as compared with its length, being nearly as wide transversely as fore and aft. It has two anterior cusps followed by a basin with elevated borders simulating two posterior cusps. There are an anterior and an exterior cingulum. The second tubercular is a miniature of the first, differing in the more robust external posterior cusp, and the absence of external basal cingulum. There are no complete cin- gula on the external bases of the other inferior teeth. The second superior tubercular is well developed, having two external tubercles. The anterior inner cusp of the superior sectorial is distinct and acute, and thei'e is a cingulum along the inner base of the crown. The exseited portion of the canines is long, slender, and with an oval section narrowed behind. Tlie enamel of all the molars is more or less rugose, a character which is only foimd elsewhere among our extinct dogs in the G. geismarianus. Measurements. ~ M. Length of cranium to iniou 10(> Lfugtli from pieinaxillary to condyles 101 Length from premaxillarv to postglcnoid 075 Length from inemaxillary to posterior border of second tubercular 041) Length to anterior border of orbit o:r. Wii'.th of occiput at superior border itf foramen maijiiitiu 02i CANID^. 901 M. Width between inner borders of postglenoitls 023 Width between maxillary bones 030 AVidth lietween orbits O'^O Widtli ofnaros 009 Leiijttli of inferior molar series 041 Linjith of bases of four jirenioiars 023 Length of base of second i)reniolar 005 Elevation ol crown of second premolar 005 Length of base of fourth premolar 0072 Elevation of crown of fourth premolar 00o5 Length of base of sectorial 010 Elevation of princi]>al cusp OOG Width of heel of sectorial '. OOli Diameter of lirst tubercular .^ '"'t''™!"'^*^""'- OO^ ( transverse 005 Anteroposterior diameter second tubercular 0037 Length of base of superior sectorial 009 Length of bases of two tubercnlars 012 Length of base of lirst tubercular 0064 The skull above described displays only two superior tubercular molars on each side, and on this account I supposed the species to belong to the genus Canis at the time I first described it. The second skull already men- tioned, exhibits the characteristic number belonging to the genus Amphicyon. A careful removal of the matrix from the extremities of the maxillary bones of the specimen first described revealed the fact that they had been broken off, since traces of the alveoli of the third superior molar were found. The following characters are presented by the second skull which is the basis of the supposed species cited in the synonymy above. The superior premolar teeth are rather short in anteroposterior diame- ter, while the tubercular molars are relatively large There are no posterior lobes on the former ; the internal and external cingula are well developed in the first and second of the latter. The third tubercular is about as wide as the second is long. The sagittal crest is only distinct on the posterior part of the parietal region. Estimated length of skull, M. .110; lengtji of superior molar series, .041 ; length of true molar series, 016; length of first tubercular, .0075 ; length of second tubercular, .055 ; width of second tubercular, .0074; length of third tubercular, .0036; width of third tuber- cular, .052 : Length of sectorial widtli between anterior external angles of first tubercnlars, .C30. ij02 THE JOHN DAY FAUNA. The teeth of this species are about half the size of those of A. vetus Leidy. The entire animal was probably about the size of the kit fox, V^dpes velox. The specimens above described were obtained by C. H. Sternberg and J. L. Wortman, in the Bad Lands of the John Day epoch, in the John Day Valley, Oregon. TEMNOCYON Cope. Paleontological Bulletin, No. 30, p. C, Dec. :!, 1878. Proceed. Amer. Phil. Soc, 1878, p. 68. Btilletiu U. S. Geol. Siirv. Terrs., vi, p. 179. Dental formula: I. =— ; C. - ; Pm. -; M. -. Two molars in each iaw %'6 14 3 ^ tubercular. Inferior sectorial with well-developed heel, which is keeled with a cutting edge above. An internal tubercle of the same. A post- glenoid, but no postparietal foramen. Humerus with an epitrochlear arterial foramen. The characters on which I rely at present for the discrimination of this genus from Canis are two. The first is the presence of a cutting edge on the superior face of the heel of the inferior sectorial, in place of a double row of tubercles surrounding a basin. When well develo^ied these char- acters present a broad contrast, but indications of transitional forms are not wanting. Thus, in some extinct Canes the internal crest of the heel is less elevated than the external, which is the homologue of the single crest of Temnocyon, and in some specimens of Temnocyon coryplioeus there is a cin- gulum on the inner side of the median keel, which represents the internal crest of Canis. Secondly, the epitrochlear foramen of the humerus, a char- acter common to all of our Lower Miocene Canidce yet known. The keel of the sectorial, which defines this genus, is simply a repeti- tion on that tooth of the heel which belongs to the posterior premolar teeth of many Carnivora. It finds resemblances in such Eocene forms as Mesonyx and PalcEOnyctis. Among recent Canidce it is apparently unknown, and is very rare in other groups. The Cynodictis crassirostris Filhol, from the French Phosphorites, stronglj^ resembles the species of Temnocyon in generic characters. CANID^. 903 Three species of the genus are known to me. They may be distin- guished as follows. A fourth species, T. josephi, is provisionally placed with these: I. First superior tubercular molar with a wide median fossa, bouuded witbiu by a tubercle. Length of suj)erior molar series from cauine, .070 ; of true molars, .0215. T. altigenis. Length of molar series from canine, .067; of true molars, .014 T. walloinanus. II. First superior tubercular molar with narrower basin, bounded within by a V-shaped crest. Length of dental series from canine, .055; of true molars, .014 T. coryphwus. Length of dental series from canine, .051; of true molars, .013; muzzle narrow, zygomaswide. T.josephi. All of the above species have been derived from the John Day Miocene beds of Oregon. I, however, anticipate the discovery of these or other species of the genus in the White River beds of Dakota and Colorado. Temnocyon altigenis Cope. Paleontological Bulletin, No. 30, p. 6 (Dec. 3, 1S78). Proceed. Amer. Phil. See, 1678, p. 63. Bulletin U. S. Geol. Suiv. Terrs., vi, p. 179. Plate LXVIII, iig. 9; LXX, fig. 11. This dog was about the size of the wolf, Canis liqms. It does not ap- pear to have been as abundant as some other species in Oregon, as I have received portions of only three individuals. Two of these are represented by mandibular rami only, one of which is the specimen on which the species was originally established. The third is that part of a skull which is anterior to the orbits, including the mandible and dentition, and it is con- siderably crushed. The first-mentioned mandibular ramus is rather deep and compressed, much more so than in the Canis latrans, with which it agrees in the length of the dental series. As compared with the existing species of Canis and Vulpes of North America, the sectorial tooth is relatively smaller and the premolars larger. In this respect it agrees with most other dogs of the. Lower Miocene, and differs from those of the Upper Miocene (Loup Fork).^ The posterior tubercle is wanting from the premolars, excepting the last, 1 See Proceedings Academy Philatlelphia, 1875, p. 22, where I have discussed the origin and hi^. tory of the sectorial tooth. 904 'I'HE JOHN DAY FAUNA. where it is large and obtuse, differing in this respect also from most recent dogs, and from the contemporary GaUaynus gregarius. In the sectorial tooth the principal cusp is much elevated above the anterior, while the inner median is small, with its apex in line with the anterior. The cutting edffe of the heel is not acute, and is a little external to the median Hne; there is a weak cingulum-like angle at its inner base. The first tubercular tooth is large, nearly equaling in anteroposterior diameter the base of the third premolar. It is parallelogrammic in transverse section, and supports two principal cusps and an anterior ledge. The cusps are pronounced, and stand exterior to the middle line; their inner side slopes to the base of the crown, where there is no cingulum. The ledge is higher on the inner than the external side. There are no basal cingula on either side of the bases of any of the teeth. The second tubercular molar is lost. The alveolar margin of the jaw rises behind the sectorial tooth, and the inferior margin begins to ascend below the middle of the same tooth more decidedly than in C. lupus, C. latrans, or A. cuspigerus. The two large mental foramina are situated, the one below the second, the other below the third premolars. Measurements. M. Lengtli of anterior six mol rs - ^'^ Length of anterior four molars "*•' Leu;;th of base of second premolar Oil Elev.itiou of crown of second premolar "H Li-ngili of base of fourtli premolar "1^ Klevat ion of crow n of fourth premolar f'1'1 Length of base of sectorial tooth 0l8o Elevation of principal cusp of sectorial tooth OIGO Elevation of anterior cusp of sectorial tooth 009 Length of heel of sectorial 007 Elevation of heel of sectorial OOS.i Length of crown of first tubercular 0115 Width of crown of first tubercular OOlio Dept h of ramus at Pm. ii 024 Depth of ramus at sectorial 02-3 Jhickness of ramus at sectorial 010 The second ramus contains the alveolus of the second tubercular -molar. The third specimen presents a mandibular dentition similar to that above described. The superior canine is large, being longer and more .acute than in the wolf. The first and second premolars are damaged; the CANID^. 905 third does not exhibit any posterior marginal lobe. The sectorial is small for the size of the other teeth, not quite equaling that of the Canis latrans. Its anterior inner tubercle is i^rominent and acute, but of small size. The tubercular teeth are relatively large, equaling those of the wolf in trans- verse diameter, but not in anteroposterior. They have a wide internal cingulum, and a single low median tubercle separated by a deep valley from the two prominent external cusps. These are bounded externally by a well-marked cingulum. Enamel wrinkled where not worn. Measurements. M. Length of siiperior dental series on base, from canine 070 Length of crown of canine 030 ^.. . .■ i • .^anteroposterior 019 Diameters 01 sectorial •; '^ . „,.,, I transverse in trout Ui.K) ^. ea i^ 1 (anteroposterior 014 Diameters of tirst trne molar { ^ ,, ( transverse -U^u ,^. ^1. 1 S anteroposterior 0075 Diameters of .seconil true molar ; ^ ,^, , I transverse "Jl* Length of series of inferior premolars 046 From the John Day Miocene of the John Day River, Oregon. Found by C H. Sternberg and J. L. Wortman. Temnocyon wallovianus Cope. Bulletin U. S. Geo!. Surv. Terrs., VI, p. 179, Feb. 11, 1881. Plate LXX : fig. 10. This species of Temnocyon is more nearly related to the T. altigenis than to any other member of the genus. Its anterior dentition is much like that of the species named, but the tubercular molars are not larger than those of the T. cori/phccus. While they differ in details of composi- tion from those of the latter species, they differ also from those of T. alti- genis. The species is only known from a cranium from which all posterior to the orbits is lost. Its molar teeth, and most of the incisors, are in good preservation. The first molar is one-rooted, and the posterior outline of its crown is quite oblique The posterior borders of the crowns of the second and third are without di.stinct lobes. The sectorial has the same size as that of T. altigenis Its blades are not very acute, nor close together. The inner 906 THE JOHN DAY FAUXA. anterior tubercle is small, and is set well inwards. The first tubercular has a very oblique external border, owing to the rapid contraction posterioily of the maxillary bone. The two external cusps have the usual direction, so that it results that the anterior external angle of the crown is very jjro- tuberant, much more so than in T. ultlgeMis. Moreover, the external basal cingulum is not defined at the base of the posterior cusp, as it is in T. aUi- genis. For the rest this tooth resembles the corresponding tooth in tl;e latter species, except as to size. The middle of the crown is occupied by a deep valley, which is bounded within on the anterior border of the crown b-S' a subtrihedral tubercle, which does not send a ridge back to the poste- rior border, as is usual in dogs. The internal cingulum is wide and flat. The second tubercular molar is relatively small, having about half the grinding surface of that of the corresponding tooth of T. altigenis. The posterior external cusp is a mere rudiment, and the cingulum is not well defined. The internal tubercle and cingulum are confounded in a uniform surface within the median concavity. The rugosity characteristic of the T. altigenis is little visible in this specimen. Measurements. M. Leugth of superior dental series on liase from canines 067 Length of bases of true molars 014 Diameters of sectorial <'''"f''^°I"'^*"'"^ ^JJ ( transverse in front Oil T^. . f i: i i 1 ^ auteronosteriiir ..; 012 Diameters ot tirst true molar < ' ( transverse at middle 015 ^,. ^ i- 1 . 1 ^anteroposterior 00.5 Diameters of second true molar ^ '^ ( transverse 010 From the John Day Bad Lands, Oregon. J. L. Wortman. Temnocyon coryph^us Cope. Proceedings Academy, Philadelphia, 1S79, p. 180. Figure 2, in Proceedings American Philosophical Society, 1880 (February). Canin harlshorniantis Bulletin U. S. Geol. Survey Terrs., V, 1879, p. 58; not Cope Anuual Report U. S. Geol. Survey Terrs., Iti72 (lb7:!), p. TiOG. Plates LXXI; LXXIn, tigs. 1-7; LXXIIa, figs. 4-7. That this dog was the most abundant species of the Oregon Miocene is indicated by the fact that the following material representing it is now in my collection: Seven crania, several of them with mandibles and more CANIDiB. 907 or less complete skeletons; seven more or less fragmentary maxillary bones with teeth, and nine more or less broken mandibles with teeth. A nearly perfect skull displays the following characters: The orbits are entirely anterior to the vertical line dividing the sktill into halves, and the muzzle is proportionately shortened. It is also narrowed anteriorly, and its median line above is shallowly grooved. The interorbital region is greatly convex to the supraorbital region, and is gi'ooved medially. The postorbital processes are mere angles, and are flattened from below. The cranium is much constricted behind the orbits, where its diameter is not greater than the width of the premaxillary incisive border. The sagittal crest is much elevated, and forms a perfectly straight and gradually rising outline to its junction with the incisor. The borders of the latter are very prominent, extending backwards considerably beyond the brain case. The zygoma is rather slender, is elongate, and but little expanded. The otic bullte are very large ; the paroccipital processes are directed backwards, at an angle of 45°, and are rather elongate and acute ; they cap the bullae posteriorly. The lateral occipital crests bound a fossa of the occipital region near the condyles. The occipital surface is directed horizontally backwards above the foramen magnum. This part of it, and its superior portion, are divided by a median keel. The basioccipital is keeled on the middle line below^ The sphenoid is not keeled, and is concave, its borders descending on the inner side of the bullae. The pterygoid fossa is rather narrow, and the hamular process is short. The posterior border of the palate does not extend anterior to the posterior edges of the last tubercular molar, and its middle portion projects backwards in a triangular process. The palatine fossa for the inferior sec- torial is shallow. The superior surface of the postorbital region is roughened. Foramina. — The foramen infraorhitale exterius is rather large, and issues above the anterior border of the sectorial tooth. The/ incisiva are short, not extending posterior to the middle of the canines. The / palatina are oppo- site the posterior border of the sectorial. The / laclirymale is altogether within the orbital border. The / opticum is rather large. This species is peculiar in having thaf.f. spheno-orhitale, rotundum, and alisphenoidale anterius united into one large external orifice. The alisphenoid canal is larger than 908 THE JOHN DAY FAUNA. in Canis latrans, and its posterior foramen small. The/ ovale is farther removed from the / alisphenoidale than in the coyote, and is exterior to and a httle behind the/ carotidemn. The nasal bones extend to above the middles of the orbits, and con- tract gradually to their apex. Their combined anterior border is a regular concave, and the lateral angles at this point are produced outwards and for- wards. The posterior apex of the premaxillary bone is separated from the anterior apex of the frontal by a short space. The maxillo-malar suture is deeply notched in front below, and it extends upwards to above the infra- orbital foramen. A very narrow surface of the lachrymal is exposed on the external surface. The pterygoid bone is distinct, and is nearly equally bounded by the sphenoid and palatine on the outer side. The inferior suture of the orbito-sphenoid runs in a groove, which is deepest anteriorly. Dentition. — The crowns of all the incisor teeth are narrow or com- pressed, and, though slightly worn, present no indication of notch. As usual, the external ones are much the largest in anteroposterior diameter. The canines have robust fangs and rapidly tapering crowns, which are but little compressed. The first superior premolar is one-rooted, and the crown is simple. The crown of the second is without posterior heel and tubercle, while the third possesses both. The sectorial is relatively short, less so than in C. latrans. The blades are low and obtuse as compared with recent species, and the notch separating them is quite open. The anterior external heel is small, and there is no anterior external tubercle. The first tubercu- lar molar is large, and the crown is narrower than that of C. latrans. It has an obtuse external cingulum, two external conical cusps, a V-shaped median ridge, and a wide internal cingulum. This crown difiers frohi the corresponding one of C. latrans in having conical instead of compressed external cusps, and a simple V-shaped crest within instead of two adjacent cusps. The second tubercular is smaller than in C. latrans, and its tuber- cles are less distinct. There are two outer tubercles, a V-shaped ridge, and an inner cingulum, all very obscure. The enamel of all these teeth is smooth. CANID^. 909 Measurements of cranium. u. Length along base of skull, including incisive border and occipital condyle 160 Length of skull to palatal notch 075 Length of skull to posterior border of pterygoid bone 102 Length to front of orbit axially 046 Width between zygomas (greatest) 094 Width between orbits (least) : 036 Width at postorbital constriction 021 W id til between bases of canines 017 Width between bases of second tnberculars 027 Width between otic bullse 009 Width between apices of paroccipitals 042 Width of foramen magnum 017 Width of occiput above , .032 The cranium above described is not accompanied by a mandible, bnt has a cervical vertebra and a scapula associated with it in the same block of matrix. The mandible of another skull exhibits the followino- characters: There is a well-developed marginal lobe of the posterior cutting edge of the third and fourth premolars as well as a low posterior heel, and a rudiment of an anterior one The heel of the sectorial is shorter than the remaining part of the tooth, and rises to a cutting edge a little external to the middle line; there is a small tubercle at its interior base. The anterior blade-cusp of the sectorial is much lower- than the median, which is conical; the two diverge, diminishing the shear-like character and action of the tooth. The internal cus]) is well developed. The first tubercular is of moderate size, and is a longitudinal oval in outline. The crown supports two low tuber- cles anterior to the middle, of which the external is the larger. The last molar has a single compressed root, and the crown is a longitudinal oval in outline. Its position is on the ascending base of the coronoid ramus, so that the crown is slightly oblique. The masseteric fossa is profound and well defined; its anterior termination is below the middle of the second tubercular tooth. The horizontal ramus is not robust, but is compressed,, and rather deep. Measuretnents of mandible. M. Length along bases of posterior five molars 049 Length of base of fourth premolar Oil EU'vatiou of crown 008 Length of base of sectorial 018 910 THE JOHN DAY FAUNA. M. Elevation of crown of sectorial 012 Leugth of base of first tubercular 0075 Width of base of first tubercular OOoO Length of base of second tubercular 0050 While the characters of this dog do not separate it widely from the genus Canis, many of them are quite different from those presented by the recent species of the genus with which I am acquainted. Thus the union of the foramina spheno-orbitale and rotunda, the anterior position of the orbits, and the postorbital constriction are not seen in the wolf, domestic dog, coyote, jackal, or the North American and European foxes. The size of the brain was evidently less than in those species, and the sectorial teeth quite inferior in the efficiency of their blades. These characters may be considered in connection with the low geological position of the beds in which the species occurs. One of the crania is accompanied by several bones of the skeleton. These are, seventh cervical and four lumbar vertebrae, commencing with the second; humerus, lacking the middle of the .shaft and cuboid bone. The seventh cervical has the centrum as large as that of the coyote, but it is more depressed, and its extremities are more oblique. The opisthocoe- lous character is not wanting, and the inferior keel is well developed. The neural canal is as large as that of the coyote, but the roof is not so wide anteroposteriorly, and the base of the neural spine extends from one edge to the other. The luml^ars are as long as those of the coyote, but the third, fourth, and fifth are narrower than in that animal. The fourth and fifth only have well developed keels. On the fifth the angle from the base of the diapophysis posterioi'ly is well marked. The anapophyses are invisible on the second lumbar, owing to injury; on the other vertebrae they are only a low ridge reaching the posterior edge of the neurapophysis. The para- pophysial tuberosities of the anterior borders of the centra below are almost nil, as in the coyote. See Plate LXXI«, figs. 2—4, where they are rep- resented two-thirds the natural size. The extremities of the centra are slightly opisthocoelous, and the articular surfaces of both extremities pos- sess a transverse, curved, shallow groove. CANID^. 911 Meas%irement8 of vertebrcc. M. i longitudinal 017 . 5 vertical (at middle) .009 i< ( ve i anterior < ^ < tri Diameters second lumbar an Diameters tiftb lumbar < transverse OUT longitudinal 0J3 terior ^ ^^^ical (at middle) 0115 ( transverse OU' longitudinal 020 , anterior < ^"t'^*^' (at middle) 012 ^ (transverse 018 The greater tuberosity of the humerus is of the usual straight form. As compared with both the wolf and coyote, both tuberosities are more produced, and the interaal terminates in an acute edge not found in the two species named. The crest of the external tuberosity is continued farther posteriorly than in the coyote or wolf, surrounding the teres insertion space, and continuing below it on the shaft. The lesser tuberosity on the other hand graduates into the head, without the shoulder seen in C. latrans and C. lupus. The condyles have a smaller diameter and much greater trans- verse extent than in either of the species of Canis cited, or in the Vulpes cinereoargentatus, thus resembling the corresponding part in the Eocene Oxi/cenidce. This resemblance is heightened by the considerable prominence of the internal epicondyle, which exceeds that seen in the recent Canidse mentioned. Measurements of humerus. M. Anteroposterior diameter of head and greater tuberosity 035 Anteroposterior diameter of head aloue 025 Anteroposterior diameter to bicipital groove 021 Transverse diameter to bicipital groove 019 transverse 021 ( tra s< i an1 Diameters of condyles.; . C external OU ' anteroposterior < i internal .. .016 Width of posterior face of condyle 014 The cuboid is a very little longer than wide. The peroneus longus groove is profound and enters at the middle of the external border. Measurements of cuboid. M. Length 012 Proximal diameter^ ^'^t^^P"^*"-'"^ 0'^' ( transverse OU A third cranium is accompanied by some bones, among which is a cal- caneum (see Plate LXXI«, fig. 7). The characters of this bone distin- guish it widely from that of the Canes lupus, latrans, and cancrivorus, and the 912 THE JOHN DAY FAUNA. Vnlpes cinereoargentatus. The sustentaculum is more expanded, and the process to which the external calcaneo-cuboid ligament is attached is con- siderably more prominent The cuboid facet is shaped much as in the gray fox, being wider than in C cancrivorus and C. latrans, and not so wide as in C. lupus. Measvrements of calcaneum. Total leugth 035 Length of lieel 021 Widtli at sustentaculum 017 Width at cuboid facet 015 Width of cuboid facet Oil Depth of cuboid facet OOTti- Depth of heel at cxtreuiity 012 This bone is but little smaller than that of an average coyote. Restoration, etc. — The proportions of this species may be derived from the second specimen described, where the skull is accompanied by bones of the skeleton. The dimensions have been about those of the Canis latrans, with some parts rather more slender. The face had a very different expression, owing to its extreme shortness, as compared with the length of the head from the orbits posteriorly. The latter dimension was the same as in the C. latrans; but. the muzzle resembled in its proportions those of a skunk or badger. The brain case is smaller than in the coyote, and the crests for muscular insertion much more elevated. As the otic bullse are absolutely larger than in the coyote, it is fair to infer a delicate sense of hearing. This was the most abundant carnivore in Oi'egon during the John Day epoch. Of the seven skulls in my possession I find but little variation in proportions. The one whose mandible is figured on Plate LXXIrt, figs. 1, Irt, is the smallest. The specimen from which the first description of this species was drawn up was obtained by Mr. J. L. Wortman Others were previously sent me- by Mr. C. H. Sternberg TtMXocYON JOSEPHi Cope. Bulletin U. S. Geol. Surv. Terrs., VI, p. 179, February 11, 1861. Plate LXX, fig. 9. The anterior portion of a cranium which supports all the teeth is all that represents this species in my collection. It is di.stinguished, first, by its- CANID^. 913 size, being intermediate between the Tennocyon corypJiceus and the Galecynus geismarianus in this respect. Secondly, it may be known by the depression of the face at the orbits and the prominence of the anterior part of the malar bone. Laid by the side of the skull of T. coryphaeus so that the posterior borders of the second tuberculars of this species and that one are in line, the canine of T. josephi originates in line with the posterior border of the first premolar of the T. coryphaeus. Of course the molars are absolutely smaller in T. josephi, but the sectorial is also relatively smaller. In T. coryphaeus the length of that tooth exceeds the space occupied by the first and second premolars; in T. josephi its length is considerably less. The third premolar of the T. josejihi lacks the posterior tubercle found in the T. coryphaeus, but a small basal heel is present. There is a narrow internal basal cingulum of the superior sectorial. The first tubercular is not so oblique as in T. waUovianus, and has an external cingulum. It has a strong V-shaped crest within the middle, which is well separated from both the external tubercles and the internal cingular border. The inferior position of the orbit is indicated by the fact that the dis- tance from its inferior border to the base of the sectorial measures one-half the distance between the anterior border of the sectorial and the posterior border of the canine. In T. coryphaeus it is three-quarters, and in T. geis- marianus it is three-fifths that distance. Measurements. M. Length of dental series from 13 062 Length of dental series from canine 051 Length of three premolars 025 Anteroposterior diameter of canine 0075 _^. . , T> ...(anteroposterior 009 Diameters of Pm. iii< ^. ' „„„ ( vertical 006 _. , /. i • ,( anteroposterior 013 Diameters of sectorial < ^ . e ^ ««» t transverse m front 007 _. ^ r nT ■< anteroposterior 008 Diameters of M. i< '^ ( transverse Oil _. . i- I, ..(anteroposterior 004 Diameters of jyi. ]i< ^ ( transverse 0075 Width of incisor series 015 The reference of this species to the genus Temnocyon is provisional, as the character of its inferior molar teeth is unknown. It is dedicated to 58 O 914 THE MIOCENE FAUNA. Joseph, the chief of the Nez Percys Indians of Oregon, a man declared by common consent to be possessed of many noble qualities, and whose political record has been altogether creditable. Found in the John Day beds of the John Day region, Oregon, by Mr. J. L. Wortman. GALECYNUS Owen. Quarterly Journal Geological Society, London, 1847, iii, 54-60. "Cpwdon Aymard, Annales Soci6t(5 du Puy, 1848, xii, p. 244. Cynodictis Bravard et Pomel, Notice sur les Ossemens Fossilea de la De- bruge, 1850, p. 5. Cyotherium Aymard, Ann. See. d'Agric. du Puy, 1850, xiv, p. 115"; Broun. Dental formula, I. -; C. -; Pm. -; M. ~. Inferior sectorial with in- 3 1 4 o ternal tubercle, and with a heel with raised or tubercular internal and external borders. First premolar in both jaws one-rooted. A postglenoid but no jjostparietal foramen. Humerus with an epiti'ochlear arterial foramen. This genus, which is abundantly represented by species and individ- uals, existed during the Upper Eocene epoch in Europe (in tlie Phospho- rites), and also during the White River or Oligocene in North America. As the structure of the feet of the numerous species from these epochs is not yet known, and, therefore, some doubt as to their correct generic reference may still exist, I only regard the genus as a certain inhabitant of North America during the Truckee or Middle Aliocene epoch. This is indi- cated by the Galecynus geisniarianus, M'here the number of the toes on the posterior foot has been ascertained. All the species of the genus from Eocene and Lower Miocene beds, as well as most of those of the Loup Fork epoch, are characterized by the relatively small size of their sectorial teeth. In this they resemble the Amphicyons, Temnocyons, and other forms of Canidce of the same period, and differ from such true Canes as C. ursinus, C. scevus, and C. haydeni, which display the enlarged sectorial teeth of the existing species of the genus. Of course there is every gradation in this respect between the two t^'pes. In the older species the internal tubercle of the inferior sectorial tooth is more largely developed than in the later ones, thus approaching some of the species of Viverridce, where it is still more largely developed. As in other characters, there are gradations in this also, so that neither in it nor in the relative size of the sectorials do I find ground for the separa- CANID^. 915 tion of the species in question from the genus Canis, as has been proposed in the case of some of the species in Europe. Through the kindness of M. Filhol, I possess jaws of a number of the species found by himself and others in the Phosphorites of Central France, including the Canis velaunus, the type of the genus Cynodon of Aymard. These agree very nearly with the species of dogs from the American Miocene beds as to generic charac- ters. Professor Owen, in the paper above cited, proposed to distinguish the genus Galecynus on account of the greater length of the pollex as com- pared with that found in the existing species of Canis. This character appears to me to be of an unsatisfactory nature, owing to the fact that gradations in the length of a digit are difficult to express with precision in other than a specific sense; and the gradations may certainly be expected to occur. I therefore formerly regarded all these species as belonging to the genus Canis. I subsequently found in the O. geismarianus a character which sepa- rates the genus from Canis, viz, the presence of the epitrochlear foramen of the humerus. In this point it agrees with AmpMcyon and Temnocyon. I arrange cotemporary and generally similar species under the same generic head,, as the most reasonable course in the absence of direct evidence. The American species of Galecynus, then, may be arranged as follows: I. Smaller species with little or uo sagittal crest. ♦Temporal ridges imiting close behind orbits; otic bullae small. Small; no exrernal ridge ou inferior sectorial O. gregarius Cope, ** Temporal ridges uniting early; otic buIlfB large. Larger; no external ridge on inferior sectorial ; teeth robust. 0. geismarianus Cope. Smaller; an external ridge on lower sectorial ; teeth more robust. (?. latidens Cope. ** Temporal ridges not uniting anteriorly; otic bullse large. Least; muzzle narrow ; superior tuberculars wide; no external ridge on inferior sectorial 0. lemur Cope. There are three species which are only known from mandibular rami, whose positions in the above analytical table I cannot fix. These are Canes vafer and temerarius of Leidy, of the Loup Fork epoch, and the C. lippincottianus Cope, of the White River. As I can add nothing to Mr. Leidy's descriptions of the first two, I only mention them here. They are probably true Canes. 916 THE WHITE RIVER FAUTSTA. Galecynus gregarius Cope. Bulletin U. S. Geol. Survey Terrs., VI, p. 181. Cania gregarius Cope. Paleontological Bulletin No. 1(5, p. 3, August iO, 1873. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 506. Bulletin U. S. Geol. Surv. Terrs., 1879, p. 58. AmpU- cyon gracilis Leuly. Proceedings Academy Philada., 1856, p. 90; 1857, p. 90. Extinct Mam- malia Dakota and Nebraska, 1869, p. 36; PI. I, fig. 7 ; PI. V, figs. 7-9. Not Amphici/on gracilis: of Pomel. Plate LXVIIa, figs. 7-11; LXVIII, figs. 5-8. In the White River beds of Colorado this species is more abundant than all the other carnivora together, and is the only one that bears due proportion to the numbers of rodentia, on which it no doubt depended for food. Slight and unimportant variations may be observed among the numerous specimens. In the Oregon John Day it is less abundant. It is a common species of the White River bad lands of Dakota and Nebraska. Mandibles from Colorado present the following characters: About half the size of the red fox {Vulpes fulvus), or equal to the V. littoralis, Baird, but with relatively deeper mandibular ramus than either. The premolars are in contact with each other, and the middle posterior lobe is well developed, except in the first, wdiicli is also one-rooted. Sectorial, with s'out inner tubercle as high as the anterior lobe; heel rather small. First tubercular with two roots relatively smaller than in the species last described, with two anterior and one posterior tubercle. The second tuber- cular is very small, and has a single subcompressed or round root. It remains in very few specimens, and in a few has evidently never existed A premaxillary with part of the maxillary bone displays parts and alveoli of two incisors, one canine, and the first premolar. There is scarcely any diastema, and the canine is compressed oval in section. The exterior in- cisor is quite large, exceeding by several times the inner one. The pre- maxillary bone has but little anterior production. Measurements. M. Length of molar series 0.036 Length of premolar series 019 Length of fourth premolar 006 Length of sectorial 009 Width of sectorial 004 Height of sectorial 006 Depth of ramus at sectorial 010 CANID^. 917 A nearly entire skull from the John Day region of Oregon is figured on Plate LXVIII, figs. 5, 8, of the natural size. Its form partakes of the anterior abbreviation common to the Canidce of the Miocene, in which that region is shorter than in recent species of Canis and Vulpes. The nearest approach to such proportions is made by the Vulpes cinereoargentatus, where the length anterior to the orbits enters the length of the skull two and a half times. In the G. gregarius the proportions of tliese lengths are as one to three. The muzzle descends regularly from the parietal region, without convexity or concavity of profile. The premaxillary border is not very prominent. The interorbital region is moderately transversel}' convex, and has a median longitudinal groove which continues to the saggital crest. The postorbital processes are not very prominent, but appear as angles, chiefly on account of the rather abrupt constriction of the cranium behind them. This constriction is not so great as in Temnocijon oryphaeus, and is more anterior in position, but is greater than in Vulpes Julvus and cinereoargentatus, or Canis latrans or cancrivonis. The brain- case is quite as large relatively as that of C. latrans. The temporal ridges extend obliquely backwards and unite to form a sagittal crest above the coronoid process of the mandible. This crest is a low ridge until it ap- proaches the repressed inion, when it becomes more apparent. The occiput IS low and broadly rounded, and its bounding crests not very prominent, resembling a good deal in this respect the gray fox. The lateral crest is -continuous and quite prominent over the meatus auditorius externus. On the occiput the protuberance for the vermis cerehelli is well marked and short and wide; it is much more prominent than in the red and gray foxes. The paroccipital process is small and obtuse, and is directed backwards. It is separated from the otic bulla by a considerable space. The posttympanic process is a rounded tuberosity which does not descend on the bulla, but is in contact with the inferior temporal crest, which is not so distinctly angulate at that point as in most recent species of Canis. The postglenoid crest is well marked, and is rather more extended transversely than in recent Canes. There is no indication of preglenoid crest The bulla is expanded, but not so much as in the other and cotemporary extinct species •of the genus. In this respect the Galecymis gregarius nearly resembles the 918 THE WHITE RIVER FAUNA. Amphicyon cuspigerus. It has no reverted lip at the meatus as in most recent dogs. The basioccipital is wide and rather flat There is a faint median ridge posterior to the middle of the bullae, which has behind, on each side, a shallow concavity, which is much less marked than in the Amphicyon cuspigerus, but which is not represented in Galecynus geismarianus. The fossa between the occipital condyle and the paramastoid process is deep. The zygomata are broken off, but enough remains to show that they are compressed, and have a lateral masseter surface, which occupies half the width of the malar process. Sutures. — The ascending process of the premaxillary is long and slender, but does not reach the acuminate anterior process of the frontal. The nasal bones are narrow, and their posterior suture forms an acute angle above the very anterior part of the orbit. Foramina. — The nareal oritice is oblique and about as wide as deep. The infraorbital foramen is large, and is over the anterior root of the supe- rior sectorial. The meatus aucUtorius externus is large, and has a narrow extension downwards and forwards. The condyloid foramen is, as in recent Canis, anterior to the transvei'se ridge extending to the paroccipital process, and is small, and quite near the foramen lacerum posterins. The bulla is closely appressed to the sphenoid, so that the/ I. anterius is of very small size. The other foramina are still concealed by matrix. The posterior or nareal border of the palate forms two shallow concavities. Dentition. — The superior incisors have simple crowns, and the median ones are very small. The crowns of the canines are slender, acute, and with an oval section. The second and third superior premolars have a posterior cutting lobe, though that of the anterior is very small. The sec- torial is small and robust. It has a basal cingulum both internally and externally. The tuberculars are moderate, the anterior narrower internally than externally, the second of equal width at both ends. Their tubercles, external cingulum, median V-shaped ridge, and internal cingulum are well developed. The three posterior inferior premolars have a well-marked posterior marginal lobe. The sectorial has no external tubercle at the pos- terior base of the principal cusp. No external cingula on the inferior molars. CANIDiB. 919 Measurements. Length of sknll to inion — - *'°' Length from preniaxillary border to edge of palate "'*" Length from premaxillary border to postglenoid process ^^ Length from premaxillary border to paroccipital process 077 Long diameter of otic bulla .0135 Elevation of occiput above foramen 0'" _. , -- (transverse 012 Diameter of foramen magnum ; , „„„ C vertical w» Width between postty mpanics 032 Width between bullae 008 Width between pterygoids 0065 Width of zygomata opposite postorbital angle 043 Width of palate at posterior angles of superior sectorials 021 Width of palate between canines 008 Width between orbits above 019 Length of muzzle to orbit (axial') 028 Length of superior molar series 031 Length of superior true molars 009 _. , . . . . ,< anteroposterior 008 Diameter of superior sectorial ■; '■ . „ ..,, ( transverse in front 0045 Diameters first tubercular < "^ '^ n„^, c transverse "Juo _. . , ^ ., 1 (anteroposterior 0035 Diameters second tuberculars •; '^ .„„„ ( transverse uubb Length of mandible to condyle 059 Depth of ramus at Pm. i 006 Depth of ramus at sectorial - 010 Besides the skull above described, fragments of three other individuals of the Qalecynus gregarius were obtained from Oregon by Messrs. Sternberg and Wortman. None of them include any portions of the skeleton. Galecynus lippincottianus Cope. Canis lippincotlianus Cope, Synopsis of Vertebrata Collected in Colorado in 1873. Miscell. Pub. U. S. Geol. Survey Terrs., 1H73, p. 9. Annual Report U. S. Geol. Survey Terrs., 1873 (1874), p. 506. Plate LXVIIo; figs. 5-6. Among the numerous remains of dogs associated with those of rodents and insectivora in the White River beds of Colorado, I have observed sev- eral portions of mandibular rami with teeth which indicate a species inter- mediate in size between the Ampicyon hartshornianus and the C. gregarius. Selecting one specimen as type, which contains the teeth which correspond to those which represent the species last described, I find the following peculiarities : .The root of the last molar is much compressed. Tliere is only a trace of cingulum on the penultimate, and the tubercles of the inner V 920 THE JOHN DAY FAUNA. side of the crown are well developed. Dimensions half as large again as in C. gregarius, as indicated by many specimens of the latter. In it the ante- rior lateral tubercles are subeqnal. A second specimen from the same locality is a mandibular ramus, with the alveoli of the entire molar series and the last premolar and sectorial perfectly preserved. As compared with a larger number of specimens of C. gregarius, the jaw is larger, but is chiefly distinguished by the relatively stouter and broader teeth. The first premolar is one-rooted. Measurements. M. Length ofbaseaofcrowns of M. II and III (No. 1) 0.0095 Length of base of crown ofM. II 0060 Width of base of crown of M. II 0035 Elevation of crown ofM. II — ...... .0030 Length of bases of five anterior molars (No. 2) 0320 Length of bases of four premolars — --• .0220 Width of sectorial at middle 0045 Elevation of sectorial at middle 0070 Depth of ramus at sectorial 0130 Thickness of ramus at sectorial 0055 A fragment of a mandible containing the last three molars found in the John Day basin of Oregon agrees in proportions with the above specimens. Unfortunately there is not enough material in my hands to render it clear whether the specimens represent a distinct species, or a large variety of the C. gregarius. For the present I retain it as distinct. Galecynus geismarianus Cope. Canis geimtariami^ Cope, Paleontological Bulletin No. 30, p. 9, Dec. 3, 1879. Proceedings American Philosophical Society, 1879 (1880), p. 71. Plates LXX, figs. 2-3 ; LXXa. This species was about the size of the fish^ Mustela pennantii, and was larger than the G. gregarius. It is represented in my collection by the greater part of a skeleton accompanied by a skull with lower jaw complete; by a second skull, from which the end of the muzzle and the teeth have been broken ; and by a fragment of a mandible which supports a sectorial tooth. On the last specimen the species was originally founded. The characters of the cranium which demonstrate the distinctness of the species, are (1) the low and long sagittal crest ; (2) the large size of the CANID^. 921 otic bailee ; (3) the long paroccipital process directed backwards and in contact with the bulla at its base ; (4) the absence of lateral fossae of the basioccipital bone. The skull is rather elongate, the elongation being behind the anterior border of the orbits. In profile the front is convex, and the top of the muzzle subhorizontal. The premaxillary border is only moderately promi- nent, and the sides of the muzzle are convex. The interorbital region is convex transversely, and the postorbital processes are small, but rather pinched, so as to be rather acute. Above the cephalic contraction behind these, the temporal ridges rapidly converge to a low sagittal ridge, which only rises into a crest when it extends backwards to join the inion. The lateral occipital crests are quite prominent and project a good deal posteriorly, giving the occiput a narrower outline than that seen in G. gregarius. It is not interrupted in its course into the suprameatal crest, as is the case in the coyote. The protuberance for the vermis is distinct. The posttympanic process is inconsiderable and is truncate below, inclosing a fossa between it and the bulla. The basioccipital presents a median longitudinal angle, which disappears between the middles of the bullae. Basisphenoid nearly plane. Postglenoid processes large, the posterior border very oblique downwards and forwards. The zygomata do not exhibit much lateral con- vexity, and the postorbital angle is distinct. The rami of the lower jaw have been under vertical pressure, so that their inferior edges are a little flattened. The symphysis extends as far back as the middle of the second premolar. The inferior border of the jaw begins to rise gradually opposite the posterior cusps of the first inferior tubercular molar, and continues with less obliquity into the long and rather narrow angle, which is not incurved, and which extends as far posteriorly as a vertical line from the condyle. The coronoid process is rather broad, and is considerably more elevated above the condyle tha;i the latter is above the angle. The masseteric fossa is well defined all round below the coronoid process, better at the anterior inferior angle than the wolf, coyote, or red fox. Sutures and foramina. — The surface of the cranium is nmch fractured, although it preserves its general form. Hence the sutures are not easily observed. The frontomaxillary has the usual upward ai'ch, and incloses a 922 THE JOHN DAY FAUNA. long strip of frontal bone with nasomaxillary sutures. The nasal bones terminate in a gradual acumination above the anterior border of the orbit. The frontal -parietal crosses the sagittal crest two-fifths the distance to the inion from the postorbital processes. The infraorbital foramen opens above the posterior border of the thii'd superior premolar. The postglenoid is at the bottom of a groove of the postglenoid process The condyloid foramen is near the / lacerum posterius, and just anterior to the anterior border of the large precondylar fossa. The foramen magnum is a little wider than deep, and has its superior border regularly arched, and without notches or angles. Dentition. — The superior incisors differ from those of Galecynus gregarius and some other species, in having their cutting edges interrupted by two notches, excepting in the external teeth, where there is but one notch, and that on the inner side. The notches are wanting or indistinct on the inferior incisors. The canines are slender like those of the red fox, but are more curved. The enamel of the inferior canine is longitudinally wrinkled, as in the fisher ; the wrinkling is less distinct on the superior tooth. The superior premolars are separated from each other and from the sectorial by short spaces. Only the third has a posterior marginal lobe. The sectorial is relatively shorter than in the G. gregarius; its length is less than that of the inferior sectorial by the length of the anterior lobe of the latter. Its inner lobe is smaller than usual. Both tubercular molars have well-developed external cusps, a valley, and in place of the V-shaped crest, two rather prominent juxtaposed subacute tubercles, much as in the first tubercular of the coyote. Within these is a well-defined valley bounded by a prominent internal ledge. There is a complete external cingulum on the first tubercular; it is incomplete behind on the second tubercular. There is no external cingulum on the sectorial or the other premolars. The inferior premolars are not so widely spaced as the superior ; the third and fourth have well-defined posterior marginal lobes, and small an- terior basal tubercles. The inferior sectorials only display thin external faces in the specimen. They have a good deal the form of those of the Amphicgon cuspigerus, and probably have wide heels. The first tuberculars are quite robust. The enamel on all the molars has a tendency to wrinkling ; and this is most distinct on the inferior sectorial and tuberculars. No exter- nal cingula on inferior molars. CANID^. ... 923 Measurements of skull. M. Length of cranium to inion ll" Length from premaxillary border to condyles 110 Length from premaxillary border to posttym panic 096 Length from premaxillary border to postglenoid 079 Length from premaxillary border to posterior border of second tubercular tooth 053 Length to anterior border of orbit (axial) 037 Elevation of occiput above foramen 023 Width of occiput at foramen 128 Width between posttympanics (outside) 040 Width between otic bullie 090 Width of zygomata opposite postorbitul angle 048 Width of palate at posterior angles of sectorials 033 Width between canines 015 Width between orbits above 023 Long diameter of otic bulla 019 Length of superior dental series, including canine 046 Length of superior premolar series 028 Length of superior true molars 013 Length of base of third premolar ^ 0065 Length of base of sectorial 0095 Width of base of sectorial in front 005 .^. . „„ , . , 1 (anteroposterior 008 Diameters of tirst tubercular ^ ^ t transverse 0094 Diameters of second tubercular J ^ ' ( transverse 00/5 Length of crown of superior canine 012 Length of crown of inferior canine 0095 Length of inferior premolar series 023 Length of inferior true molar series 022 Length of base of inferior fourth premolar 0075 Length of base of inferior sectorial 0115 Length of base of inferior first tubercular 0064 Length of base of inferior second tubercular 0035 Length of ramus maudibuli to angle 077 Depth of mandible at coronoid 038 Depth of mandible at sectorial (partly restored) 012 Depth of mandible second premolar 010 Of vertehrce there are preserved five cervicals, two represented by parts only; ten dorsals, four lumbars, three or four sacrals, and five caudals. The cervicals have the characters of those of typical Canidce and ViverridcB. The centra are moderately elongate, and their articular surfaces moderately obliquely opisthoccelous. They are strongly keeled inferiorly, the keel run- ning out into a hypapophysial tuberosity on the posterior border of the centrum, where it terminates abruptly. There are opisthapophyses, or small but distinct tuberosities on the borders of the neural arches of the third and fourth cervicals. The seventh is strongly keeled below, the carina widening into a flat triangle posteriorly, and not produced downwards. The inferior 924 THE JOHN DAY FAUNA. side of the centrum is sharply defined laterally by an acute border extend- ing posteriorly from the base of the diapoi^hysis. The anterior articular face of the centrum is a transverse oval, looking a little downwards. The capitular rib-facets of the dorsal vertebrae are quite small, making very slight emarginations of the borders,, and those of the last thi'ee verte- brae are entirely on the anterior portion of each centrum The first dorsal is not keeled below, and the second has a slight downward projection of the anterior border. All the other centra are rounded below, and their articular extremities are halves of circular disks, except those of the last, which are more depressed. The centra increase matei'ially in lengtli pos- teriorly, and the elontjate ones show traces of the keel, which is well marked on the lumbars. On the antepenultimate centrum an angle of the circumference of the posterior ai-ticular face appears just below the line of the neural canal. On successive centra it becomes more prominent, and descends to the inferior plane. It is so prominent as to be a process on each side on the first lumbar. The succeeding lumbai-s increase in length so as to be twice as long as the anterior dorsals; indeed, nearly three times as long as the first dorsal. They have a low inferior keel, a lateral angle extending from the diapophysis, and a low keel -like neural spine ex- tending the length of the neural arch. The diapophyses have short and narrow bases at the anterior extremity of the centrum. They commence, as usual, as lateral ridges on the dorsals. The first ridge is visible on the penultimate dorsal, extending obliquely backwards and upwards from the superior border of the capitular facet. The anapophyses are very large on the last three dorsals and the first lumbar. They are small on the antepe- nultimate lumbar, and absent from the last two. The metapophyses are first developed on the penultimate dorsal. On the first lumbar they are large, and have enlarged rounded summits. They are absent from the last three lumbars. The last lumbar is short, as in most carnivora, and has a rather low neural spine, which extends along tlie entire length of the neural arch. There are three sacral vertebrae, which have a keel for neural spine, which is most elevated on the last. Four caudal vertebrae are in place, succeeding the sacrum. They all have well-developed diapophyses, which are directed backwards and are of depressed section. The neural arch is com- CANID^. - 925 plete on all, and not much shortened on the fourth. A more distal caudal has no neural arch, but a median ridge on the posterior half and an ele- vated lateral process in front. Nearly the entire length is occupied by a thin diapophysis on each side. As compared with other Cariiivora, the cervical vertebrae most resemble those of' Canidce niul Viverridce, as already observed. The dorsals differ from all of the former in their greater elongation, especially posteriorly. The lumbars differ from those of dogs, and from those members of the Mustelidoi and Viverridce wliich are within my reacli, in their greater elonga- tion. They resemble those of Canidce in the anterior position and short bases ef the diapophyses. They differ from tliem in the long, low neural spines, and resemble those of Putorius erminca. The lumbars also resemble those of that species, and of the Mangusta ajnculata, in the size and posterior persistence of the anapophyses. In the large development of the processes and arches of the caudal vertebrae the Galecynus geismariarms resembles the Viverridce. The vertebrae above described were found as follows: Two cervicals and parts of two others were taken from one block; one cervical and three dorsals from another ; two dorsals from another. Five dorsals and one lumbar were adherent to the side of the skull. Four lumbars were attached to the block containing the sacral and four caudal vertebrae, pelvis, humerus, and fore foot. Measurements of vertehrce. M. anttroposterior 016 Diameters fourth cervical .^ . (vertical - 005 C an 'erior <, „„.^ transverse Wii _. , 1 , r • .(transverse 007 Diameters neural canal of cervical < . , „„„ ( vertical 006 ( longitudinal 013 Di'ameters seventh cervicaK . (vertical . ... 006 i anterior I '" "■ ( transverse 0077 Length centrum of second dorsal 010 ( anteroposterior 0117 < . . < V( iiosrenor i ansverse Oil Diameters fourth dorsal from last/ . (vertical 0057 [<■ . ( v( ( posterior I . ite: t posterior^ i anteroposterior 0145 Diameters last dorsal'^ ^ . < vertical 006 transverse Oil Diameters neural canal last dorsal} < transverse OOljo. 926 THE JOHN DAY FAUNA. H. Elevation of neural spine of laat dorsal 020 Elevation of metapophyses first lumbar 018 anteroposterior 024 Diameter antepenultimate lumbar < . (vertical 0067 / posteriory .,„ '^ (transverse 012 Length of last lumbar vertebra 014 Length of sacrum 025 Length of four anterior caudals 042 Expanse of diapopbyses fourth caudal 018 Vertical diameter centrum fourth caudal .' 0045 Length of centrum longer caudal 018 Vertical diameter of longer caudal 006 The scapula is in a damaged condition, the coracoid process being lost. The spine is high, most so at the acromion. The glenoid cavity is lost above the line of the spine; the remaining part has the transverse greater than the vertical diameter, and is very little concave. The tuberosities of the head of the humerus are prominent, especially the great one. The latter does not extend as far posteriorly as in Temnocyon corpphceus, and is obliquely truncated by the teres facet. The proximal border of the great tuberosity is a ridge, but neither tuberosity develops a ridge of the shaft. The anterior face of the latter is rounded. I find this part of the humerus a good deal more like that of Canis than those of Mangusta, Putorius, or Mustela, where the tuberosities continue immediately downwards into an- gular ridges. The shaft of the humerus is lost. The distal portion is pre- served. It resembles that of Mangusta rather than that of Canis or the Mustelidce. It has greater transverse extent both as to the condyle and the epicondyles than in Canis sp., but rather less than in Temnocyon coryphceus. The internal flange of the condyle is well developed, but the radial con- vexity is weak. The olecranar trochlea is narrow, and the fossa is deep, rather narrow and transverse and not double as in some Mustelidce. The proximal parts of the ulna and radius are preserved. The inferior edge of the ulna is turned inwards. The bicipital tuberosity of the radius is well marked, and bounds a fossa which is between it and the head. The latter presents a wide oval to the humerus. The anterior foot of the right side remains attached to the block which contains the pelvis, and from which the right humerus was cut. It includes the proximal halves of the metacarpals except the first, and the magnum, unciforme, and cuneiforme of the carpus. CANID^. 927 The latter do not differ much from those of Canis, with one important excep- tion. The cuneiforme and pisiforme are coossified. Whether this is an individual peculiarity, or a character of the species or of the genus, future observations only can decide. The character does not exist in my speci- mens of Mangusta apiculata, Putorius erminea, Mustela pennanti, nor in any of the Canes in my collection. The second metacarpal has the proximal lateral facet for contact with the first metacarpal, and the small tuberosity below it for ligamentous connection. The shafts of the metacarpals are subequal in diameters and of subround section near their middles. The pelvis is preserved in position nearly entire. Its general form is more elongate and compressed than in Canidce and Mustelidce generally, and more compressed than in Mangusta. The postacetabular portion is more like that of the Felida; in its narrowness and compression, but the ischiopubic symphysis is more compressed and keeled than in the latter family. The crests of the ilium are broken oif, but fi-agments show that they reached as far forwards as the anterior margin of the last lumbar ver- tebra. They are moderately wide and flat, and the external face is gently concave. There is a weak anterior inferior spinous tuberosity. The spine of the ischium is a convexity of the narrow superior edge of the ischium, which descends a little to the flatter part of the border representing the lesser sacroischiatic notch. The portion of the ischium which descends to the symphysis is compressed and subvertical ; the notch the opposite sides define, is V-shaped, and deeper than in the species of Canidce or other Car- nivora above mentioned. The obturator foramina are large and are longi- tudinally oval. Measurements. M. Elevation of spine of scapula 010 Transverse diameter of glenoid cavity of scapula 0075 ■ior 020 016 Diameter of head of humenis to bicipital notch 015 Diameters of shaft of humerus f'"'t«™''°«t*'"'"- 0105 ( transverse 0065 Diameter distal end of humerus (greatest) \ anteroposterior 012 ( transverse 018 „. . , , , „. ( anteroposterior, median 006 Diameters of condyles of humerus ^ '^ . ' """ ( transverse in front 012 Diameter of shaft of radius at middle 0055 Width of palm without pollex Ol.T Diameters of head of humerus (greatest) \ e p s eno < transverse 928 THE JOHN DAY FAUNA. M. Probable length of pelvis l'^2 Length of ilium (inferential) 037 Anteroposterior width of ilium at base 013 Anteroposterior diameter of acetabulum 013 Depth of pelvis at ischiapubic symphysis 018 Width of obturator foramen Oil The fragment of lower jaw above mentioned was the specimen from which the existence of this species was originally inferred. Its characters are as follows : The mandibular ramus is robust and shallow, and quite distinct from the deep jaw of A. hartshornianus. The sectorial has perhaps twice the bulk of those of the G. lippincottianus and A. cuspigerus. From that of the latter it differs further in the small inner tubercle and contracted heel. The sectorial part of the tooth is relatively small, not exceeding the heel in length, and its cusps are low. The heel is notable for the elevation of the tubercle of the inner side, which exceeds that of the outer ; the latter also is contracted, standing within the external base, which is represented by a short cingulum. A weak cingulum below the sectorial blades. Sur- face of the enamel rugose where not exposed to friction. Measurements. M. f vertical, anterior cusp 006 I vertical, heel 0038 Diameters of sectorial jj^j^^gj.j,p„gjgri„^ 0115 1 transverse, middle 006 Depth of ramus at sectorial 012 Thickness of ramus at sectorial 007 The third specimen, a cranium, already mentioned, displays the base of the skull more distinctly than any other. The condyloid foramina are seen to be close to the / /. postica, and the / caroticus is not externally distinguished from the latter. The / alisphenoidale posticum is small, and is wiell in advance of the large / ovale. The / a. anticum is within ihe / rotun- dum. The latter is large and distinct from the / sphenoorbltale. The post- glenoid is rather large. The meatus auditorius externus is a sub vertical oval; has no slit-like enlargement, nor a recurved lip. The palatine foramina are opposite the inner border of the first tubercular molar. A shallow groove extends anteriorly from each for a considerable distance. The maxillo- palatine suture crosses the middle line of the palate opj^osite the anterior border of the sectorial. The frontal sends a long process anteriorly on each CANID^. 929 side of the nasals, which does not meet the ascending process of the pre- maxillary. It also descends along the extei'nal border of the orbit to the lachrymal. The latter presents a very narrow surface external to the orbit, and supports a narrow tuberosity on the prominent border of the latter. The malar ascends to near this tuberosity in a narrow process, which is more acuminate in form than in Canis latrans or Vulpes fidvus and V. cinereo- argentatus. The lachrymal bone is much larger than in an}' of the above species or the C. familiaris or C. cancrivorus, and is especially expanded at its superior portion. The orbitosphenoid bone extends as far anteriorly as in those species, but carries no diagonal ridge, as in the latter. The orbito- nasal foramen is much more posterior than in them. The squamosal bone is long and low. There is a slight concavity on the superior surface at the base of the postorbital process of the frontal bone, as in the recent red fox. The palatonareal border is a regular concavity. The otic bullae are large and somewhat compressed. They are longer than deep, and as deep as wide. Restoration. — Although the skull and pelvis of this species have about the size of those of the fisher, the ■'•ertebrse and humerus are more slender, and the anterior foot is decidedly smaller. It is probable that the Galecynus geismarianus resembled a large Herpe&tes in general proportions rather than a Canis. It stood lower on the legs than a fox, and had as slender a body as the most " vermiform " of the weasels, the elongation being most marked in the region posterior to the thorax. The tail was evidently as long as in the Ichneumons. Its carnivorous propensities were as well developed as in any of the species mentioned, although, like all other Canidce of the lower Miocene period, the carnassial teeth are relatively smaller than in the recent types. History. — The specimen above described, which includes the greatest number of bones, was obtained by my assistant, Mr. Jacob L. Wortman, from the Haystack Valley, Central Oregon, from beds of the John Day Miocene age. The skull last described was found by C. H. Sternberg in the "cove" of the John Day Valley of Oregon. The species is named in honor of Jacob Geismar, an accomplished and skillful naturalist of Phila- delphia. 59 c 930 THE JOHN DAY FAUNA. Galecynus latidens Cope. Bulletiu U. S. Geol. Survey Terrs., VI, p. 181, Feb. 11, 1881. Plate LXX; figs. 4,5. The specimens which represent this species are the following: (1) A skull distorted by pressure and lacking the j^ortion in front of the sectorial teeth, accompanied by a mandibular ramus anterior to the base of the coro- noid process; (2) a mandibular ramus similar to that of No. 1; Nos. 3, 4, and 6, fragments of mandibles supporting sectorial teeth. The specimens show that the Galecynus latidens was intermediate in size between the G. gregarius and the G. geismarianus, and diflfered from both in various respects. The crushed condition of the cranium renders the description of the form of the brain-case difficult. The lateral occipital crests are more produced posteriorly than in the allied species. The paroccipital process is much as in G. geismarianus, but is more closely appressed at the base to the otic bulla than in it. The apical portion is free from the bulla, and is directed principally downwards. The bullae are quite large, and are oblique ovals, as wide as deep. The masseteric face of the proximal part of the malar bone is lateral, and extends above the middle of the same. The lachrymal bone is wider above than in most Canidce, but is not so wide as in G. geismarianus. The sectorial molar is short, and its internal tubercle is well developed. The tuberculars are distinguished for their anteroposterior width, both being as wide near their inner as at their external borders. Their external cin- gula are well developed ; their external crests are rather low. They have a median V-shaped ridge, and a wide internal cingulum. There is a short posterior cingulum on the second tubercular. The mandibular ramus is compressed and rather deep. The teeth are not spaced, and the fourth premolar is obliquely placed, so as to overlap externally the anterior lobe of the sectorial. Both the third and fourth premolars have a well-developed posterior marginal lobe; the second pre- molar is lost from all the specimens. The third premolar is moderately compressed, but the fourth is more robust in its proportions than in any other species of the genus. Both premolars have an anterior and a poste- rior heel, the former minute. The sectorial is distinguished by the relative CANID^. 931 length and width of its heel, in which it exceeds any other of our species; and by the possession of a narrow tubercle at the external base of the princij^al cusp. This is a little higher than the heel, but not so high as the internal tubercle. This character is seen in the Vulpes cinereoargentatus among recent dogs. It is present in the four well-preserved sectorials of my collection. The first tubercular is relatively large. It has four cusps, all marginal, two anterior and two posterior, and an anterior basal ledge; no other basal cingala. The second tubercular is missing from all the specimens. There are two mental foramina, a larger below the posterior part of the first premolar, and a smaller below the third premolar. One of the mandibular rami of this species I described along with the skull of Galecynus lemur, under the impression that it belonged to an individual of that species. This error is now corrected. Measurements. H. Length of skull, exclusive of muzzle, anterior toPm. iii 070 Length of skull from anterior border of orbit posteriorly 060 Length of skull from postgleuoid process 032 Length of otic bulla 020 Width of otic bulla '. 010 Diametera of sectorial ^*°*'"'°P°«*«"<"' "07 c transverse iu front 0055 Diameters of first tubercular | '»'it«'™P''«t«'"'"- 007 ( transverse 008 Diameters of second tubercular I '^°t'''-°P°«t«"°'^ 0045 ( transverse 005 Length of inferior dental series 048 Length of sectorial 008 Length of heel of sectorial 0035 Length of inferior tubercular 055 Depth of ramus at sectorial 0105 The typical specimen above described was obtained by Mr. J. L. Wortman in the cove of the John Day Valley, Oregon, in the John Day Miocene foi'mation. One of the mandibles was found by Mr. C. H. Sternberg. Galecynus lemur Cope. Bulletin U. S. Geol. Survey Terrs., VI, p. 181. Cania lemur Copo. Paleontological Bulletin No. 31, p. 2, December, 1879. Proceedings American Philosophical Society, 1879 (1880), p. 371, exclusive lower jaw. Plate LXX; figs. 6-8. This animal is represented iu my collection by the following speci- mens: (1) A cranium with premaxillary region preserved, without lower 932 - THE JOHN DAY FAUNA. jaw and with the parietal region injured; (2) a cranium without muzzle or lower jaw; (3) a cranium lacking- all posterior to the frontoparietal suture; (4) a cranium mutilated like the last, and without muzzle or lower jaw; (5) a left mandibular ramus, broken off behind first tubercular; (6, 7, and 8) fragments of three mandibular rami. This species is the smallest of the genus yet discovered in the Miocene formation of Oregon. It is characterized by the contracted proportions of the muzzle, the width of the front, and the large size of the orbits. The postorbital process is only a short angle. The superior border of the tem- poral fossa is traceable from the postorbital process. Those of opposite sides embrace a smooth sagittal area of an elongate urceolate form, and vmite posteriorly in a very short crest. The species is further characterized by the large size of the first superior tubercular molar and the swollen otic bullae, which exceed relatively those of any other species of the genus. While the muzzle is shorter in the species of Galecynus described in the- present work than in existing species of Canidoe, the G. lemur still further diminishes the size of this region by lateral contraction. The profile de- scends gradually and regularl}-, and the ^^remaxillary bone is quite oblique and prominent below. The interorbital region is wide and is quite flat. The orbit is large, and the postorbital angle of the zygoma well posterior. The occiput is much contracted; its lateral angles are well defined but not very prominent, and become obsolete on the mastoid regions. The tube- rosity for the vermis is distinct. The precondylar fossa is narrow, and is, as in other species, bounded by a transverse ridge, which extends from the paroccipital process to the basioccipital median line. The paroccipital process does not descend below'the level of the occipital condyles; it is appressed to the otic bulla to near its extremity, which is free and directed downwards. Its external surface, as far as the occipitosquamosal ridge and posttympanic process, is flat. The latter process is a mere tuberosity, and does not descend on the bulla. The postglenoid is nan-ow and small, as in recent Canidce, and its external border extends obliquely downwards and inwards. The bullee are very large, and of a moderately compressed oval form. They do not present a prominent lip at the meatus. The zygomata are more widely expanded than in any other species of Lower Miocene CANID^. 933 Canidce of which this part is preserved, excepting Leidy's Atnpliicyon vetus (PI. I, fig. 1, Extinct Manimaha Dakota and Nebraska). The nareal trough IS, by comparison, nai-row. The posterior palatal or nareal border is regu- larly concave. The palate is gently concave. Sutures. — The preniaxillaries do not reach the frontal bones. The lachrymal is wide at its inferior part and narrows upwards as in the foxes. The orbitosphenoid extends to the vertical line from the postorbital process of the frontal. The contact of the alisphenoid and parietal is extensive. Foramina. — The infraorbital foramen opens above the posterior root of the third premolar. The / magnum is wider than deep, and has its superior margin regularly arched. The / conchjloideiun is near to the / lacerum jposteriiis, but is distinct. There is a foramen in the position of the / <;arotideum of the Viverridce on one side; it is wanting on the other, and cf&es not occur in the second skull. I suppose, therefore, that it is abnormal. It is interesting as possibly indicating a tendency to variation in the direc- tion of the civets. The meatus auditorius externus is not enlarged down- wards, and is an oval directed downwards and forwards. The / ])ostgle- noideum, is rather large, and is cut off from the meatus by the anterior rim of the latter. The / ovale is large, and is very near the / lacerum anterius and well posterior to the alisphenoid canal The// rotundum and spheno- orbitale are large, and are only separated by a thin partition. The / orhi- tonasale has the posterior position seen in other species of the genus. The / / palatina are opposite the anterior part of the internal borders of the first tubercular teeth. Bentitioit. — Three premolars, two true molars, andiin incisor remain in this specimen. The crown of the incisor is worn; the alveolus of the canine indicates usual size for the tooth. Crown of first premolar simple. Third premolar compressed, with a well-developed posterior cutting lobe. Sectorial robust, rather wide in front, but with the inner lobe small. The tuberculars are large, and wide anteroposteriorly, but not so wide as in G. latidens. The external cingulum is entire on the first, and disappears posteriorly on the second. The cusps are not elevated, and there are a median V-shaped ridge and internal cingulum, on both teeth. 934 THE JOHN DAY FAUNA. Measurements (2fo. 1). Length of skull to inion 080 Length of muzzle to orbit 027 Length to postglenoid process 056 Length of skull to paroccipital process 071 Width at middle of zygomata 040 Width at posttympanics 030 Width between canine teeth 007 Width between sectorials behind 020 Width between otic bullae 007 Width of foramen magnum 009 Width of occiput at foramen 019 Width between orbits 0115 Elevation of occiput from foramen 014 Length of dental series from I. 1 038 Length of molar series 027 Length of true molars 009 Length of sectorial 007 Diameters of first tubercular 5 ^° ^ P _._-, < transverse Witi 0038 0052 _. . , . , , S anteroposterior . Diameters second tubercular < ( transverse The second skull already mentioned has its superior walls entire pos- terior to the interorbital region. The temporal ridges are, as in various species of foxes, first convergent, then divergent, and then convergent again to a very short sagittal crest close to the inion. The measurements of this specimen are as follows: Leugth of cranium to front border of orbit, M. .0525; elevation of occiput, .058; length of superior sectorial, .007; length of first tubercular, .0058; width of first tu- bercular, .0078; width of second tubercular, .005; length of second tubercular, .0035, The most perfect mandibular ramus was found separately (No. 5). It agrees in all necessary respects with the crania. It is, like the muzzle of the latter, attenuated anteriorly, and the molars have corresponding propor- tions. The fourth premolar is compressed, and has an acute posterior cutting lobe, besides acute anterior and posterior basal tubercles. The inner tubercle of the sectorial is very prominent; there is no trace of tubercle at the external base of the principal one as is seen in G. latidens. The heel is quite concave ; like the first tubercular, it is narrower than the corresponding tooth of G. latidens. The latter tooth has a wide anterior ledge, two elevated tubercles, and a heel with raised semicircular border. CANID^. 935 Measurements of lower jaic. Length to end of first tubercular 033 Length of premolar series 017 Length of sectorial 008 Width of sectorial posteriorly 0036 Length of first tubercular 0047 Width of first tubercular 0030 Depth of ramus at sectorial 0080 Depth of ramus at first premolar 0050 The enamel of the inferior molars is strongly wrinkled. The man- dibular ramus I originally ascribed to this species belongs to the G. latidens, as proven by another jaw which was found with the skull of that species. The specimens Nos. 1, 2, and 5, described as typical of this species, was discovered in the John Day River Beds of Oregon, by J. L. Wortman; specimen No. 3 was found by Mr. Sternberg, at the same locality. ENHYDROCYON Cope. Bulletin U. S. Geological Survey, V, 1879, p. 56; American Naturalist, 1879, 131, 1883, p. 245. 1 3 2 Dental formula : I. ? ; C. - ; Pm. - ; M. -^. The superior premolars 1 Of consist of two ordinary and one sectorial; the first and second are both compressed, two-rooted, and in the typical species with median lobe of pos- terior cutting edge. The two true molars are transverse and tubercular. The three inferior premolars are all two-rooted, and with posterior lobe, in the known species. The heel of the sectorial Is cutting, as in Temnoci/on, and the internal tubercle is present. There is at least one inferior tubercular tooth ; specimens are injured so as not to display a second. The dentition of this genus refers it to the Canidce, but the form of the skull resembles that of Putorius and Lutra. Unfortunately no other part of the skeleton of this genus is known. Enhydrocyon stenocephalus Cope. Bulletin loc. sup. cit., 1879 (Feb. 28), p. 56. Plate LXLX; figs. 3-5. In a nearly complete cranium belonging to this species we observe the shortness of the facial part of the skull as compared with the length of the cerebral, and also the constriction of the skull behind the orbits. The 936 THE JOHN DAT FAUNA. zygomatic arches are robust and expaoded, and the sagittal crest is high. The auditory bullae are inflated and thin-walled. The orbits look some- what forwards and very little upwards. The superciliary region is slightly prominent, and there is a prelachrymal concavity. The infraorbital foramen is moderate, and is situated mostly above the posterior part of the fourth premolar. The muzzle is flat above, and the nasal bones are wide, and are not emarginate above the osseous nares, as in many recent Carnivora. Pos- teriorly, the superior border of the brain-case descends, but the parietal bones maintain a gently convex outline in their high sagittal crest. The supraoccipital region is elevated, and projects posteriorly. The lateral occipital crests are prominent to the base of the paroccipital process. The latter projects strongly posteriorly, and is connected with the bulla by an osseous mass which is continuous with the inner border of the process. It is connected with the posttympanic b}' a longitudinal crest, which includes a deep groove between it and the otic bulla. The posttympanic is a tuber- osity which extends downwards below the middle of the meatus auditorius, and is not in contact with the bulla. The postglenoid process has greater transverse extent than in the recent species of Canis. There is no trace of preglenoid crest. The basioccipital bone is elevated on the middle line, so as to include a deep fossa on each side between it and the otic bullae. There is no trans- verse ridge connecting this ridge with the paroccipital process, as in Canis, Galecynus, and Temnocyon, but the fossa above mentioned is continuous with the precondylar fossa. The basisphenoid is not keeled, and its lateral borders rise on the otic bullae in a thin lamina on each side. The pterygoid fossa is narrow for the size of the skull, but is appropriate to the attenua- tion of the postorbital region. The posterior nareal border does not advance in fi-ont of the posterior line of the last molar tooth, and is a double con- cavity, the dividing angle being little prominent. The maxillary is not notched on each side of the palatine on its posterior border, as in the Am- phicyon hartsJiornianus. The palate is medially flat, but its sides descend to the alveolar borders, rendering the whole convex upwards. The face is concave behind the canine alveoli. The orbits are small, and the postor- bital processes are obtuse angles. The postorbital process of the zygoma CANIDiE. 937 is not prominent. An obtuse bridge extends upwards to the postfrontal process along the superior border of the orbitosphenoid bone, as in recent dogs. Sutures and foramina.— As the skull is that of an old animal the sutures are obliterated. The anterior nares are small and but little oblique, though not so vertical as those of the Lutra valetoni, fide Filhol. They are about as wide as deep. The infraorbital foramen is rather small, and is widely oval in form. The palatine foramina are opposite the posterior part of the sectorial, more anterior than in Galecynus lemur. There are, however, two other foramina of smaller size, one opposite the anterior part of the first tubercular, the other behind the posterior margin of the second tuber- cular, near the posterior nostril. Lachrymal foramen rather large ; orbito- nasal medium. Optic moderate ; / / sphemorhitale and rotundum separated by a lamina only, the latter receiving the / alisplienoidale anticum. F. a. posticum small and in a fossa common to the rather small / ovale. F. lacerum anterius small, divided into two, and bounded inwardly by an obtuse ridge of the sphenoid directed forwards from the anterior region of the bulla. No distinct carotid foramen. F. lacerum posticum small and linear. F. condyloideum rather large, situated between the anterior and posterior por- tions of the large precondylar fossa. Foramen magnum rather small, wider than deep. Mastoid very small ; postparietal large ; no postsquamosal. Meatus auditorius nearly round, without reverted lip separating the post- glenoid from it. Dentition. — The teeth of this skull are worn with age and use. The sectorial is short and is widened anteriorly. The first tubercular is large, and has considerable transverse extent ; it is a little wider externally than internally, and has much the form of the corresponding tooth in Canis. The second tubercular is transverse and small, not being much more than half the length of the first, and is situated in contact with it. Measurements. M. Total length of cranium 0.170 "VViiltli across zygomatic arches •- 0.114 Least width behind orbits 0.024 Depth of cranium with crest at otic bulla 0.070 Vertical diameter of orbit 0.025 Length from orbit to end of muzzle (axial) •. 0.040 938 THE JOHN DAT FAUNA. M. Interorbital width 0.043 Width of muzzle above second premolar 0.018 Length of superior molar series - - 0.051 Length of fourth premolar 0.012 Length of sectorial 0.016 Length of first tubercular 0.008 Width of first tubercular 0.015 Width of second tubercular 0.0085 The dentition is better displayed by a second specimen. This consists of the middle portion of a mandibular ramus and anterior part of the max- illary of a young animal. The teeth are not fully protruded and their crowns are beautifully perfect on exposure. The principal cusps of the inferior premolars present cutting edges, as does the median posterior lobe. In both third and fourth there is a small conic heel posteriorly, but an ante- rior basal tubercle on the fourth only. The sectorial is large and robust, and the heel is short, with an absolutely median cutting edge. The first tubercular is longer than wide, and presents a nearly median cusp in front, which is joined to a low one on the internal border of the crown. The superior canine has an obtuse cutting edge on the anterior and posterior borders of the inner side. The first (third) superior premolar is near to it, and is rather large, displaying a median cutting lobe and low pos- terior heel. The fourtli is similar but larger. Measurements of No. 2. M. Anteroposterior diameter of second superior premolar 0.010 Anteroposterior diameter of third inferior premolar 0.013 Width of base of third inferior premolar 0.0065 Elevation of crown of third inferior premolar 0.010 Diameter of inferior sectorial \ ~ „„, ( anteroposterior v.u4i Width of first tubercular C'006 Remarks. — The Enhjdrocyon stenocephalus is an aberrant member of the family Canidce. Besides the generic characters already pointed out, it presents numerous specific peculiarities. Especially to be noticed is the arrangement of the parts between the postglenoid process and the occipital cond3'le. These do not present striking affinities to any form outside the Canidce, so far as I can ascertain. Restoration, etc. — Without limb-bones the general form of this species CAXID^. 939 cannot be inferred. It was as large as the coyote in all probability, and its facial physiognomy must have been that of a large mink or otter. Its canine teeth are formidable from their size, and the high sagittal crest and wide zygomata indicate great power in the action of the lowerjaw. If anything may be derived from similarity of cranial form to the otter, its habits were aquatic. Its large otic bullae indicate a well developed and sensitive sense of hearing. In the development of these parts it is only exceeded among the Canidce here described ])y the Galecynus lemur. OLIGOBUNIS Cope. American Natura'ist, 1881, June (May 19), p. 497; 1883, p. 246. The dental formula is, I- ., ; C. - ; Pm. - ; M. -. The single superior tubercular molar is similar in general to that of other Canidce. The inferior sectorial has an internal cusp and posterior heel, the latter with a basin and low cutting edge on one side. Inferior tubercular well developed. The only known species of this genus I formerly referred to Iciicyon of Lund, which it nearly approaches. It seems, however, that in that genus there are two tubercular superior molars, and the heel of the inferior secto- rial is trenchant as in Temnocyon. Fig. 34. — Olifjobunis crassiridtus Cope, one-half natural size, a, right maxillary lioue witli teeth from below ; b, right mandibular ramus from above. From the John Day river of Oregon. •940 THE JOHN DAY FAUNA. Oligobunis crassivultus Cope. American Naturalist, 1881, p. 497, and 1882, p. 246, fig. 14. Icticijon crassivultus Cope. Proceedings Academy Philadelphia, 1879, p. 190. Plate LXIX ; fig. 1, 2. The specimen representing- this species is a skull with both mandibular rami in place, and without the parietal and occipital regions. These parts belonged to an animal of about the size of the American badger (Taxitlea americana). The snout is short and robust, and the profile from the parietal region is straight and descending. The premaxillary border projects but little "beyond the line of the extremity of the nasal bones. The muzzle is slightly contracted in front of the orbit and above the fundus of the canine alveoli. The latter cause a swelling on the side. The interorbital region is some- what cracked, but appears to have been nearly flat medially; laterally it descends steeply to the supraorbital border. The orbit is not large, and the zygomatic fossa is short. The nasal bones are narrowed posteriorly, a little contracted medially, and expanded anteriorly, their lateral portions being produced along the premaxillaries. Their combined nareal border is con- cave, and is without the notches of some forms. The foramen infraorbitale exterius is of medium size, and issues above the interval between the sec- torial tooth and the one in advance of it. The mandibular ramus is quite robust, and its inferior border is gently convex. The masseteric fossa is bounded by elevated borders especially inferiorly, and the angular hook is prominent and robust. The cond3'le is situated on the horizontal line of the tubercular molar, or a little above the others, and has a wide transverse extent, chiefly inwards. The coronoid process is high and wide, and is turned backwards so as to vertically overhang the condyle. Its anterior border is wide below, and becomes horizontal above. The teeth partake of the robust character of the skull, with the excep- tion of the incisors. Of these, the crowns of the external are long and narrow, and the median small in the premaxillaries, while those of the lower jaw are all small, and in a regular series. -The canines in both jaws are quite robust, and those of the lower jaw are rather abruptly recurved. The first premolar is small, and has a simple crown and single root. The OANID^. 941 crowns of the other premolars are wide at the base and form each a simple cone, with a short posterior basal heel. The sectorial is relatively not long, but is robust, and with thick blades. The internal heel is well developed as in Canis, while a cingulum represents an anterior lobe. The tubercular molar is narrower in fore and aft diameter than in Temnocyon coryphceus, or Canis Jafrans, although it presents the same details. These are a wide obtuse external cingulum, two external tubercles, a median, an obtuse in- ternal tubercle, and a wide internal cingulum. The premolars of the lower jaw are similar to those of the maxillary bone. The inferior sectorial is quite robust, and the internal cusp is well developed. The heel is shorter than the blades of the crown, and is wide and without tubercles in its some- what worn condition. Its external border rises to an edofe. The tubercular is wider than the corresponding tooth in the cotemporary species of Camdce, although not so wide as long. Its crown rises in two low tubercles which stand transversely near the middle. Measurements. M. Length of skull to orbit (axial) 049 Depth of skull to orbit (axial) 042 luterorbital width 040 Width of uarcs 017 Length of superior molar series 03S Length of bases of three premolars 019 Length of base of sectorial 013 Width of sectorial in front 009 AVidth of first tubercular anteroposteriorly 006 AVidth of first tubercular transversely 014 Length of mandible to angle 093 Elevation at coronoid 051 Elevation at sectorial 0^0 Length of inferior molar series 045 Length of inferior sectorial 014 Length of heel of inferior sectorial 003 Length of inferior tubercular 006 Width of inferior tubercular 005 Van der Hoeven has given^ descriptions and figures of the skull and dentition of the Icticyon venaticiis of Lund, of Brazil. From these it appears that the present species differs from the latter in the greater development of the inner part of the tubercular molar of the superior series ; in I. venaticiis this pai-t is much reduced. The tubercular molar of the lower jaw is also 'Overhet Gestlackt Icticyon; wis. cu natucirk. vert, der Koninkl. Akademie Amsterdam, Deel IIL 912 THE JOHN DAY FAUNA. much smaller in the living species, the angular and coronoid processes less developed, and the condyle less extended transversely. The cranium of the I. crassivuUus is much more robust, but not much longer than that of /. venaticus. Discovered by Mr. J. L. Wortman in the John Day beds of the John Day River region of Oregon. HYAENOCYON Cope. Palseoutological Bulletin No. 31, 1879, p. 3 (Dec. 24) {dejinitione falsd) ; Proceedings American Philo- sophical Society, 1879, p. 372 (definitione fahd. American Naturalist June (May 19), 1881, p. 497 {dejinitione emendatd). This genus rests on the characters furnished by two species, which are represented by but few remains. Its family position is doubtful, and my reference of it to the Canidce is only provisional. It may, so far as the evi- dence goes, be a member of the 3fustelidce or even of the Felidce. Dental formula : I. §; C j; Pm. |; M. ^. Last superior molar robust, transverse, like that of the Canidce generally. Inferior premolars all two- rooted, and with well-developed posterior cutting lobe. Inferior sectorial large, with heel. Probably no inferior tubercular tooth. The characters above given agree with those of Oligobunis in the su- perior true molars, but differ in the absence of the Pm. I. and the M. II. in both jaws. The typical species is tlie Hycenoct/on sedorius {Enhydrocyon hasilatus partim Cope olim.), from the John Day beds of Oregon. Hyaenocyon basilatus Cope. Bulletin U. S. Geol. Surv. Terrs., vi. 181, Feb., 1881. Enhydrocijon basilatus Cope, Bulletin U. S. Geol. Survey Territories, v. 1879, p. 57. American Naturalist, 1882, p. 246, fig. 13 e. Plate LXXV; fig. 3. This rare species is certainly represented in my collection by parts of only one individual which is known from the greater part of both rami of a mandible, from which only the sectorial, one canine, and some incisors of one side have been lost. These portions indicate an animal of the same general character as the Enhydrocyon stenocephalus, but of larger and more robust proportions, and characterized by many dental peculiarities. These will be at once pointed CAiTiD^. 943 out. The canine is directed upwards and a little outwards, and posseg§es two obtuse ridges bounding the interior face. The third incisor is com- pressed and truncate superiorly and distally. The first (second) premolar is two-rooted, compressed, and trilobate. It consists of a principal cutting edge little elevated, and a small accessory lobe at each extremity of the crown ; its base is expanded posteriorly. The principal cusp of the third premolar is more elevated, and, besides the anterior and posterior tubercles, there is a basal posterior heel, which is continued as an expansion of the inner base of the crown. In the fourth premolar, the base of the crown is expanded, especially posteriorly ; the principal cusp has a nearly circular section at the base, and the posterior median lobe is a subconic tubercle standing on the middle of the heel. The sectorial is large and relatively rather narro'w, but the details of its form are not ascertainable. Measurements. M. Length of dental series, including canine and sectorial 0.076 Length of the base of the sectorial 0.024 Length of the premolar series 0.037 Length of the fourth premolar 0.016 Width of the fourth premolar 0.009 Length of the third premolar 0.013 Width of the third premolar 0.008 Length of the second premolar 0.009 Width between centres of crowns of fourth premolars 0.034 Length of symphysis 0.035 This species was probably of the dimensions of the Gray Wolf Found by Mr. Sternberg in the same region as the U. stenocephalus. Hy^nocyon sECTOEiiJS Cope. American Naturalist, 1882, p. 246, fig. 13 d. Hycenocyon hasilatus pars Cope locis alteris citatis. Plate LXX ; fig. 1. This species is represented by a right maxillary bone in which the last three molars remain, with the alveolus of the first molar and the canine. I formerly supposed this piece to belong to the H. hasilatus, and it furnished the characters of the genus Hyoenocyon in the peculiar dental formula it pre- sents, li belonged to too small an animal to be referable to that species. The alveolus of the canine tooth shows that the latter is of large size, and that the root and base of the crown have a round section. The first premolar (second) follows without interspace, and all the teeth succeed each 944 THE JOHN DAY FAUNA. other without interruption. The second premolar is two-rooted, but the roots are close together, and the anterior is the smaller. The long axis of the tooth is oblique to that of the jaw, and the posterior root is within as well as behind the anterior. The axis of the third premolar is very little oblique. It is a robust tooth, and the crown is a little wider anteriorly than posteriorly. The apex is subconical, and there is a posterior intermediate tubercle whose section is wider than long. The heel is narrowed and not recurved. There is no anterior tubercle or cingulum. The sectorial tooth is relatively of lai-ge size, its proportions being those of the FeUdce and Hijoenidce. Its crown is broken in front, and where not broken, is worn by use. It displays the peculiarity of a remarkably short blade posterior to the lateral external notch ; and the base of the mid- dle cusp of the crown is wide for a sectorial tooth, and was apf)arently sub- conical when complete. It is also situated remarkably posteriorly, showing either that the anterior sloping edge is long as in Arclicdurus dehilis, or that there is an anterior basal lobe, as in the species of JElurodon (figs. 35, 36). The internal lobe is altogether anterior, and, though worn off in the speci- men, was probably small. The long axis of this tooth is that of the jaw. The tubercular or first and only true molar is as large a tooth as in Canidce generally, but its external border is more oblique to the line of the other alveoli. The posterior external cusp is well developed, though smaller than the anterior; and the anterior external angle of the crown is so promi- nent as to become worn by use like the true cusps. The latter are placed well within the external base of the crown, which is prominent, but rounded, not forming a distinct cingulum. The internal half of the crown is broken away. The internal root comes so near the posterior edge of the maxillary bone as to prove the non-existence of a second tubercular molar. The enamel is smooth in all these teeth, and there ai'e no cingula. Measurements. M. Length of dental series from posterior edge of canine alveolus 058 Length of base of Pm. ii 008 Leugth of base of Pm. iii 013 Width of base of Pm. iii _ 008 Diameters of sectorial ^ '^"t«™P''«*«"''5 .- -O'^" ( transverse m front 013 External width of m. 1 (obliqne) 013 Transverse width m. i, including internal root 021 ca:jjid^. 945 This species, as already remarked, has some resemblance to the FeUdcc in its very short face, and large sectorial tooth. It clearly does not closely approach any of the species of the Nimravidoi of contemporary age. A principal peculiarity is the large size of the tubercular molar. Such also is the robust form of the second and third premolars. These resemble somewhat those of Enhjdrocijon stenocephalus^ but are not so much compressed. They resem- ble those of the species of JElurodon more than those of any other carnivore. Fig. 35.— Jaws of JEhtrodons, tluee- Finally, the eigUtbs natural size. Figs, a, h—Ji. . 1 • 1 n ^ whielermntts Cope, from Nebraska. t;ylindriC base of the cannie tooth is that OI the pjg. c—Ji. hi/anoictes Cope, from Ne- braska. (^The secoml true molar lost.) Both from Loup Fork beds. Canidce rather than the Nimravidce. Fig. 36. JEIiirodoii savits Leidy, from tbe Loup Fork beds of Nebraska, three-eighths natural size. Copied from Plate CXVIII of this work. 60 C 946 THE WHITE EIVEE FAUNA. BUN^LURUS Cope. Synopsis of the New Vertebrata of Colorado, 1873, p. 8. Annual Report United Statea Geological Survey Territories, F. V. Hayden, 1873 (1874\ p. 508. The specimens from which this genus is known exhibit a part of the inferior dentition only, so that the number of premolars is unknown. It is probable that there are four premolars however, and there are two true molars, the first of which is sectorial. The sectorial tooth is like that of Putorius. It has no internal cusp, and has a well developed blade. It has also a well developed heel, which has a trenchant median keel. Tubercular molar one, with a median cutting- edge. Tliis genus probably belongs to the Mustelidoe, and is allied to Putorius, and perhaps to Gulo. It is not probable that it has the reduced number of premolars of the former genus, but is more apt to agree with the latter genus, and with Plesiogale Pom. in its formula. I have even referred to it under the name of Gulo,^ from which Plesiogale ^ has never been really dis- tinguished. The form of the tubercular tooth is, however, very peculiar, and is different from what is seen in any of the species of the genera last named. Structurally the term tubercular does not apply to it, as it is a cutting tooth, without cusps or tubercles. An apjjroach to this form is found in Putorius, but in Galictis the tubercular molar is of the ordinary ty|De. I know but one species of Bimcslurus. Bun.s;lueus lagophagus Cope. Synopsis New Vertebrata Colorado, 1.S73, p. 8. Annual Report U. S. Geol. Survey Terrs., 1873 (1S74), J). 50H. Plesiogale Cope, on plate of the jiresent volume. Plate LXVIIa; figs. 13,14. This species is represented by parts of the lower jaws of two indi- viduals, one adult, the other immature. The latter is the more instructive, as it presents the third and fourth premolars emerging from the jaw, and the first and second true molars fully protruded. The crown of the fourth premolar is between the roots of the deciduous sectorial, which still remains attached to the jaw. ' Bulletin U. S. Geol. Surv. Terrs., VI, p. 45. The best description of the dentition of this genus is given by Cones. — The Fur Bearing Animals of America, pp. 39,40, 1877. - See Filhol Mammiferes Fossiles de Saint Gerand le Pny, 1879, pp. 177-190, Plato 25, who refers the species to Muatela. CAENIVORA. 947 The crowns of the premolars are simple, and narrow anteroposteriorly, and without posterior lobe. They expand at the base both fore and aft, but do not present basal tubercles. In the sectorial, tlie median cusp is much more elevated than the anterior. Its posterior face is flattened- convex, while its anterior cutting edge is acute. The cutting edge of the anterior cutting ridge is horizontal, and is separated from that of the larger cusp, by a deep closed notch. No trace of internal cusp. The heel is shorter than the anterior lobe, and is about as wide as long. The inner side of the median keel is concave, and is bounded below by a cingulum, while the external side is convex, and has no cingulum. The second true molar has two roots, and is longer than wide. It narrows posteriorly. Its median cutting edge curves a little inwards anteriorly, and the external base forms a small angle of the opposite side. No cingula. The deciduous sectorial differs from the permanent, in having a con- cave heel (perhaps jjartly worn), and a slight angular trace of the internal cusp. Measurements. M. Length of four last molars on bases - 0140 Length of permanent sectorial fore and aft 0050 Length of heel of do 0010 Elevation of anterior cnsp do 00;!0 Elevation of median ctisp do 0045 Diameters tubercular molar ^ '^"*^^°P°*'''"°^ ^'^- ( transverse 0013 Diameters sectorial of No. 2 ^ ' ^ ( vertical of median cusp 0040 Depth of ramus mandibuli, No. 2, at sectorial 0070 Fi'om the White River beds of Northeastern Colorado, found by myself with bones of Perathermm, Eiimys, Palceolagus, etc. It is quite possible that the animal from the same locality which I named Canis osomm (see Plate LXVII a), is the same, or a second species of the genus. The typical specimen is not in a good state of preservation. NIMRAVID^. The dental characters of the Nimravidce are in general those of the Felidce, the higher genera having the same dental formula. Descending the scale, the number of molar teeth increases at both ends of tlie series in the lower jaw, and anteriorly only in the upper, but the number of the true 948 THE MIOCENE FAUNA. molars never exceeds ^. The following table gives the definitions of the genera. I unfortunately do not know the foramina in Pseudcelurus. I in- troduce Procelurus for comparison, although as I have pointed out/ it is a member of the Cryptoproctidce. I do this the more readily as it is quite possible that when the number of the digits of some of the species now in- cluded under the Nimravidce comes to be known that they may prove to have them five on both feet, and hence to be members of the Cryptoprodidoe. I. Lateral and anterior faces of mandible continuous ; no inferior flange. fl. Inferior sectorial with a heel ; canines smooth. Molars ji ; inferior sectorial with interior tubercle Prowlurus^ Molars f^ ; inferior sectorial without interior tubercle Psetidcelurus. II. Lateral and anterior faces of mandible separated by a vertical angle ; no inferior flange; incisors obspatulate. a. No anterior basal lobe of superior sectorial ; inferior sectorial with a heel (and no internal tubercle) ; incisors truncate. Molars ^i; canine smooth Archcehirus, Molars |^; canine denticulate JEhirogale. Molars fi; canine denticulate Nimravus. III. Lateral and anterior faces of mandible separated by a vertical angle ; an inferior flange ; incisors conic ; canines denticulate.^ «. No anterior basal lobe of superior sectorial;' inferior sectorial with a heel; no posterior lobes of the crowns of the premolars. Molars |i Dinictis. Molars fx PiHionodon. Molars ?^ ^ - • HopJophoncus.^ Molars ^^ ... EusmUus. It is readily perceived that the genera above enumerated form an unusually simple series, representing stages in the following modifications of parts : (1) In the reduced number of molar teeth ; (2) in the enlarged size of the superior canine teeth ; (.H) in the diminished size of the inferior canine teeth ; (4) in the conic form of the crowns of the incisors ; (5) in the addi- tion of a cutting lobe to the anterior base of the superior sectorial tooth ; (6) in the obliteration of the inner tubercle of the lower sectorial, and (7) in the extinction of the heel of the same ; (8) in the development of an inferior 'American Naturalist 1881, p. 339. rroalurus b.as also beeu shown by M. Filhol to be one of the Cryptoproctidm. It is also iinccrtaiu whether Pseiidaliinis lielongs to the Ximravida-. " Gervais' figures of the cauines of Eusmilus bidcntalits represent no deuticulations, but the figure la- not clear. 'Rudimental in Hoplophoneus. NIMEAVID^. 949 flange and latero-anterior angle of the front of the ramus of the lower jaw; (9) in the development of cutting lobes on the posterior borders of the larger premolar teeth. (1) The reduction in the luunber of molar teeth. The dental formula of Proceluriis is that of some Viverridce and Canidce, and the reduction from this point to the end of the series is obvious. In Eusmilus, as in Smilodon, the number of molai-s is less by one in the inferior series than in Lijnx and Neofells, where the formula is the smallest known among Felidce proper, viz: f^. (2) The enlarged size of the superior canine teeth. In Procelu- 7-HS and Pseudcelurus tlie canines of both jaws are developed as in recent Felidce. In Archcelurus the superior is the larger, but does not, relatively to the molars, exceed that of Felis. It is rather compressed in form and has a sharp cutting edge posteriorly. In Nimravus the superior canine begins to have the enlarged size of the saber-tooths, but its form is peculiar in the N. (jomphodus, being spike-shaped rather than saber-shaped. We find the true saber shape first in the Dinidis, where it is compressed, and with a denticulate cutting edge on both front and rear. In Pogonodon it has reached a very large size, and it does not display much increase in this respect until we reach the last genus of the series, Eusmilus, where its proportions are enormous, almost as large as in the feline genus Smilodon, where they appear to have been an inconvenience to the animal. (3) The diminished size of the inferior canines becomes evident in the lower genera of the third division (supi-a) of the Nimravidce, but is most decided in the highest genera, Hoploplioneus and Eusmilus. (4) The incisor teeth have the usual obspatulate or obovate outline in the genera of the first and second divisions of the family, including Nimravus. They are conic in the true saber-tooths with flared lower jaw, beginning with Dinictis and ending with Eusmilus. (5, 6, and 7) The structure of the sectorials. The presence of a heel and an inner tubercle of the lower sectorial are well-known charac- ters of a majority ot the Carnivora. In only the most highly organized genera are they wanting, and among them are included all those of the Felidce that still exist. In the Nimravidce the inferior genera have both in a reduced degree, and they soon disappear as we ascend the scale. Thus, the inner tubercle is only present in the species of Procehrus, Dinidis, and 950 THE MIOCENE FAUNA. Hoploplioneiis. The heel, on the other hand, remains throughout the entire family. The anterior basal lobe of the superior sectorial has the same his- tory, its absence being characteristic of the inferior Carnivora, and of all the genera of Nimravidce except Hoplophonevs, where it is rudimental. It is well developed in Drepanodon as in recent Felidce, and is sometimes double in Smilodoii. (8) The development of the inferior flange and latero-ante- rior angle of the mandibular ramus. There is a successive advance in the development of these characters, beginning with the second group, for in the first they are wanting. The latero-anterior angle is developed in Ar- chcclurus and allied genera, and is merely continued on the inferior border of the ramus. In the third group it is much more acute, and is deflected downwards, forming the well-known flange of the saber-tooths. It is long- est in the EusmUus bidentatus Filh. (9) The highest genera of Nimravidce, e. g. Hoplophoneiis, difi'er from true Felida' in the absence of the cutting lobes on the posterior edges of the crowns of tlie larger premolar teeth. But, according to Filhol, these lobes are present in the generalized genera Procelurus and Psendoelurus, which are thus brought into a relation with the Felidce not possessed by the Nimravidce. A characteristic perfection of the Felidce is seen in the genus SmUodoti; that is, the vertical direction of the ungual phalanges, by which the claws become retractile. This is well displayed by the two splendid specimens of Smilodoii necator from Buenos Ayres, which have been preserved.^ Un- fortunately, these phalanges have not yet been described in any species of the Nimravidce, and it is not yet certain what their structure really was. Among the true Felidce the genus Cyncelurus displays a less degree of devel- opment in this respect than the other genera, the ungual phalanges lacking the proxunal process below the articular facet. Such a condition is to be looked for among the less perfect genera of Nimravidce. The succession of genera above pointed out coincides with the order of geologic time very nearly. Those belonging to groups first and second belong to the Lower and Middle Miocene, except ^lurogale, which is per- haps Upper Eocene, and Pseudcelurus, which is Middle Miocene. The genera of the third division have the same Lower Miocene age, except Eiismi- ' See American Naturalist, December, 1880, fig. 12. NIMRAVID^. 951 h(S, which has been found in the same formation (Phosphorites) as the ^Jiirogale. Among Felidce, Drepanodon is Upper Miocene, and Smilodon is Pliocene. The relations of these genera are very close, as they differ in many cases by the addition or subtraction of a single tooth from each dental series. These characters are not even always constant in the same species, so that the evidence of descent, so far as the genera are concerned, is con- clusive. No fuller ffenealoorical series exists than that which I have discov- ered among the extinct cats. As to the phylogeny of this family, there are flesh-eaters of the Eocene period which may well have been the ancestors of both the Niinravidce and Felidce." I have suggested that this position is most appropriately held by the Oxycenidce, a family of several genera, which included the most formid- able, rapacious mammals of that early period in both continents. The inter- val between them and the Nimravidce is, however, great; for in the Oxycenidce, when there is a superior sectorial tooth, the first true molar in the upper jaw is utilized instead of the last pi-emolar, and the second true molar below is a sectorial as well as the first. Several intervening forms must yet be found to complete the connection, if it have ever existed. It is, however, very likely that the true Felidce were derived from the genus Procelurus, through Pseudcehtnis, if indeed these two genera be not the primitive members of that family, for, as above remarked, the evidence of their possession of the characters of the Nimravidce has not yet been obtained. There can be no reasonable doubt that the genera Drepanodon and Smilodon in the Felidce are the descendants of Hoplophoneus and allied genera. In fact, the Nimravidce and Felidce are "homologous groups," having con-esponding terms in the manner I foreshadowed as a general principle in 1 868 (Origin of Genera). ' JI. Filhol lias sUowu the range of variation in the JElurogale intermedia to he considerable. While the normal dental formula is as given above, molars § J, he believes that it may I'ange to ^ | iu one direction, and i yi or | }, in the other direction. It never attains the formula J i of Arcliwlurus^ while the occurrence of two premolars in the lower jaw is rare. Originally M. Filhol was inclined to. believe that there were three species, and this view is confirmed by the range in size. The largest specimens measure .0t:5 M. ou the alveolar line behind the canine, and the smallest .030, or less than half as long. The discovery of various intermediate sizes led M. Filhol to combine the three species into one. I incline to think M. Filhol's belief in three species to have better foundation thau his belief in hut one. Were the animals living, it is prob.able that their characters would be much more readily defined than is possible with the jaws only. Meraoircs sur quelques MammifSres Fossiles des Phosphorites du Quercy, Toulouse, 18*2. = See On the Genera of the Creodoiita, liy E. D. Cope, Proceed. Amer. Philos.. Soc. July, 1880. 952 THE MIOCENE FAUNA. The following list shows the number and distribution of the species of the Nimravidce. The position of a cross on a line indicates an intermediate geological position. Upper Eocene. Lower Miocene. Upper Miocene. Pliocene. i 2 1 'C 5 i £ •s < Asia, Eu- rojie. =1 o + 1 -1- j^ilurojjale iiiterraeilia Filli ^•Ehirogale minor Filh + + + Xioiraviia ""oimiliofliis C'oi'K' -U 4- + u Diuictis Sfiii.ilidena Coiie + L U Hoplophoneus oreodontis Cope + + Hoiiloiilioncus priiiKf'vus Leidv i ' U Hoploplioneus strifideus Cope . . -1- + 1 i 0. AS. Fig. 37. — JrchaJnnai iliJiilis, om'-hall' iiat. sizp; inferior .nspft-t. Foramina: AS, alisplicuoiil; O, ovale; PG, postgleiiold; C. carotid: Co, coiulylar. ARCH^ELURUS Cope. American Naturalist, 1870, p. 798a. Procecil. Amcr. Pbilos. Soc, 1879, p. 37Q (Jan. 18S0). Paleouto- logical Bulletin, Ko. 31, p. 3, Dec. 24, 1879. .3 1 4 1 Dental formula I., ^ ; C, ; P-m., . ; M., - Mandiljular ramus .> 1 o 2 without flaring inferior border anteriorly. Superior canines without cut- NIMEAVID.E. 953 ting edge anteriorly; posterior edge not sen-ate. Incisors with short, slightly spatulate crowns. Postglenoid and postparietal foramina jjresent. Superior sectorial tooth without anterior lobe. Inferior sectorial with heel, and without internal tubercle. No intermediate posterior lobes of the pre- molars. This genus is of interest as completing the connection between the saber-tooth and primitive unspecialized groups of the cats, a transition also clearly indicated by the genus Nimravus. In dentition it adds a tooth to the number belonging to that genus in both jaws, and has a smooth-edged canine; it is otherwise identical with that genus, unless, indeed, the exos- tosis supporting the inferior sectorial tooth in the A. dehilis be introduced into this category; a position I am not prepared to assume. The molar dentition only differs from that of Dinictis in the addition of a single tooth to the superior series, but that genus has the compressed superior canine and flared mandibular ramus of the saber-tooth. Archcelurus also eases the passage from these genera to the Procelurus of Dr. Filhol, a highly in- teresting genus obtained by that gentleman from the ])liosphatic deposits of Central France. Procelurus has one more molar in the inferior series, and its inferior sectorial exhibits an internal tubercle similar to that seen in Dinictis. Like Archceluriis, it is not a saber-tooth. But one species of Archceluriis is known thus far, and this one has been found in the John Day Miocene of Central Oregon. Arch^lurus debilis Cope. American Naturalist, December, 1879, p. 798 a (published Dec. 4). Palaeontological Bnlletiu, No. 31, p. 3, Dec. 24, 1879. Proceed. Aiiier. Philos. Soc., 1879, p. 372. Plate LXXIn, tigs. 8-16; plate LXXII. This species, which is about the size of the panther (Uncia concolor), is represented in my collection by parts of the skeletons of three individ- uals. First, a cranium with mandible complete, and the atlas; second, a cranium without mandible, but otherwise complete; third, a cranium ante- rior to the zygomatic fossa, without dentition or mandible, but accomj^anied by a lumbar vertebra; proximal part of scapula; both extremities of hu- merus; proximal part of ulna; tilth metacarpus; both extremities of tibia; 954 THE JOHN DAT FAUNA. the astragalus and first metacarpal. As the cranium first mentioned fur- nishes the greatest number of cliaracters, I select it for description. The profile of the skull is convex, much as in the panther, but it appears to be somewhat less so, owing to the greater prominence of the premaxillary border. The front is rather wide at the postorbital region, and it is convex on each side of a wide shallow median lonffitudinnl con- cavity. Tlie nasal bones are rather stout, and carry their width backwards before contracting to an apex, which is above a ])oint 2:)Osterior to the lach- rymal foramen. The external portion of their anterior extremity is con- tinued as a process of moderate length along the premaxillary bone, about as far as the width of the superior border of each nostril. The superior process of the premaxillary does not reach the frontal bone by .17'". The superior face of the frontal region is prolonged backwards so as to be partly diamond-shaped, owing to the gradual approximation of the anterior borders of the temporal fossae. This form differs from that seen in the panther and leopard, and is more like the shape found in the jaguar and tiger. The extinct species differs from all of these in the very small de- velopment of the postorbital process. This is simply a slight prominence of the superciliary border; in only one of the three specimens deserving so much as the name of an angle. The brain-case is not more contracted behind the orbits than in the Uncia concolor. Anterior to the orbit the face is shallowly concave above the region external to the canine alveolus, which is convex. The sagittal crest is low, and the lateral crests of the inion are not very prominent. The latter do not overhang the foramen inagnum so far as in the panther. The zygomatic arch is characterized by its slenderness, and the rudimental character of the postorbital process, so well developed in the existing Felidce. It is less expanded posteriorly; that is, it is more nearly parallel with the axis of the skull than in the large recent cats. The occiput is not elevated. Its posterior face is divided by a short keel Avhich descends from the inion one-third the distance to the foramen magnnm. The latter is wider than deep, and its superior border is not furnished with the tuberosities so well marked in the panther, and less so in the leopard and tiger. The foramen magnum is much as in the Lynx rufns. The paroccipital process is moderately long, is acute, and is directed NIMRAVID^. 955 obliquely backwards. The front tympanic process is an obtuse tuberosity whose anteroposterior diameter exceeds its longitudinal. The occipital condyles are well separated below. The basioccipital is first flat below, and is then divided by a delicate median keel. The latter soon terminates, sending off a curved line to the anterior inner border of, each otic bulla. The area on each side of the keel is divided into three shallow fossse and an anterior plane. Anterior to the keel the base is plane, except a shallow fossa on each side. The posterior margin of the palate is gently concave to the line of the principal cusp of the superior sectorial. It is not so deeply concave as in the panther. The otic buUje are large, as in existing cats. The rami of the mandible are quite slender, in correspondence with the character of the zygomata. The inferior border of the masseteric fossa, though prominent, accompanies the inferior edge of the ramus for a short distance only, and gives it little width. The symphyseal portion rises abruptly from the rami ; it is narrower below than above, and is concave in transverse section near the middle The angle which sejiarates the lat- eral from the anterior face of the ramus is rounded, and is continuous with the inferior border. This form is not seen in the species oi Fells, Uncia, and Cyncelurus, and is a trace of the characteristic angle and flange of the saber- tooths. The posterior angular process is straight, compressed, and acute, and the condyle is quite narrow. The osseous tuberosity beneath the inferior true molar teeth is a most peculiar feature. It looks as though the external alveolar border had been greatly extended, and then folded down and attached to the side of the ramus. Its free borders are a vertical and a horizontal, which are connected by a rounded angle. The ascending border passes into the base of the coronoid process by a roughened ridge. The inferior border and external face are also slightly roughened. Foramina. — The incisive foramina are large. The / infraorhitale exterius is especially large, and opens forwards. Its external border is thin, and is convex in profile ; it is above the posterior edge of the last superior pre- molar, when the skull is resting on a plane surface. The / opticum is rather large, and occupies the position usual in existing cats. The / splie- noorbitale is quite large, and is round. The / rotundum is smaller than the 956 ' THE JOHN DAY FAUNA. optic foramen' and issues in the posterior side of the / sphenoorhitale, and not separately as in the species Uncia at my disposal, the Cyncchiriis jubatus, and in several species of Fells. An alisphenoid foramen. The / ovale is ransverse in direction and is well separated from the / lacerum anterius. The latter is contracted. The / postglenoiduni is nearly as large as the / ovale, and is near the anterior border of the meatus of the ear. The latter is small, and is bounded below by a distinct ossification, probably a tym- panic bone, which is thickened so as to resemble somewhat a sesamoid. 1 find it in the two specimens Avhere the region is preserved. There is no foramen lacerum med'ms, and the / carotideum is well defined from the / /. posterius, which it about equals in size. The / condi/loideum is quite distinct from the latter, of about the same size, and does not enter it from behind so as to have a common opening, as in the species of Felis, Uncia, Cyncelurtts Crocuta and Hycena. Supraglenoid, postquamosal, subsquamosal, and mas- toid foramina wanting. The postparietal is rather small, and is situated in the anterior inferior part of the posterior third of the parietal bone. There ai-e two lateral and two anterior mental foramina on each side. Of the former, the posterior is below the posterior part of the second premolar, and the anterior below the first premolar. Dentition. — There cannot be said to be any diastema in the superior dental series excepting that between the canine and the first incisor. The inferior diastema occupies the usual position, but has diminished length. The first and second superior incisors are quite small ; their crowns are about as wide as their roots, and, meeting the inferior incisors squarely, are trun- cated by wear. The external superior incisor is several times as large as the others, and its crown is expanded outwards at the base. It presents an external worn face several times as long as its apical face. The superior canine is relatively about as long as in the panther. It is a good deal more compressed than in that species, and has a sharp posterior cutting edge which extends from near the alveolus to near the apex. This edge is not crenated. There is no corresponding anterior edge, though the wearing of the inner side of the crown by the inferior canine produces an artificial one near the apex. The front of the canine is rounded, but is not as wide as in existing cats. NIMRAVIDuE. 957 The first supeinor premolar is one-rooted, and is of moderate size. The second is two-rooted and is small. The third is abruptly larger. The ante- rior face of its principal cusp is wide, and has no basal lobe ; it is not trench- ant posteriorly. The heel is long and rather obtuse. The fourth premolar or sectorial is relatively large. There is no anterior basal lobe, and the internal lobe is small. The cusp is robust, and not very acute posteriorly. The heel is long. The true molar is of medium size, and its external face reaches the line of the external faces of the premolars. Its grinding face is oblique upwards and backwards. The inferior incisors are much like the superior, excepting the external one, which is only about twice as large as the others, and of the same form. The section of the inferior canine is nearly the quarter of a circle, the angle looking backwards from the inner side. It is much larger than the superior external incisor. The first inferior premolar is one-rooted, and its alveolus is as large as that of the first superior premolar, and is situated close to that of the second. The second (third) is quite large ; it has an anterior basal angle, and a short posterior heel, but no posterior lobe of the prin- cipal cusp. The last premolar is larger. With the inferior sectorial it is concealed in part by the superior teeth, as the lower jaw has not been removed from its position. The posterior part of the sectorial shows a dis- tinct, rather acute heel, like that of the Nimravus hrachyops. The tuber- cular or second true molar is small and obtuse, and is directed more ante- riorly than superiorly, owing to its situation on the base of the coronoid process. In all the teeth the enamel is smooth, and there are no cingula. Measure/nints of skull. M. Axial length from occipital condyles to premaxillary bonier 180 Axial length from iuion to premaxillary border 191 Axial length from premaxillary border to canine tooth 008 Axial feugth from premaxillary border to anterior border of superior sectorial 0.'58 Axial length from premaxillary border to palatal border 075 .Vxial length from premaxillary border to end of maxillary bone. 080 Axial length from premaxill.ary border to postglenoid process 135 Length of nasal bone from notch 050 Length of sagittal crest from iniou 064 Width of premaxillary bones at canines 034 W'idth of anterior nares 027 Width of n.asal bones at middle 020 Least width between orbits 028 Width at postorbital processes 060 Width behind postorbital processes 034 958 THE JOHN DAY FAUNA. M. Width of zygomata at anterior border of orbits 080 Width at meatus auditorius 130 Width between paroccipital processes 053 Width of occiput at middle 032 Elevation of occiput above foramen 03"2 Width of foramen magnum 02'2 Depth of foramen maguum 014 Width between etic bull» 016 Width of posterior nares 013 Width of chin at base 020 Width of chin at summit 027 Length of superior canine 026 Anteroposterior diameter at base 013 Anteroposterior diameter at middle 010 Transverse diameter at middle 0065 Length of superior molar series 057 Length of bases of Pm. i and ii 0105 Length of base Pm. iii 018 Elevation of crown of Pm. iii 010 Length of base of Pm. iv 024 Width of base in front 010 Elevation of base in front 012 AVidth of M. i (transverse) Oil Length of base of inferior Pm. iii 014 Length of base of inferior Pm. iv 015 Elevation of base of inferior Pni. iii Oil • The atlas attached to the cranium above described is not entirely cleaned from the matrix. It displays a vertebrarterial foramen piercing- the base of the transverse process posteriorly, as in various species of Felis and Uncia, and as distinguished from the lion. The base of the transverse process has a smaller anteroposterior width than in any of the species of Felidce or Hj-aenas accessible to me. The neural arch has a similar char- acter; a low tuberosit}' represents its neural spine. The second specimen mentioned resembles the one already described so nearl}' as to render extended notice unnecessary. The crowns of the small first premolars have been broken off, but traces of their roots remain. The third specimen displays the root of the first premolar with the others. The palatal surface exhibits a fossa opjjosite the heel of the superior sectorial to receive the apex of the inferior flesh-tooth. A last or seventh lumbar vertebra, belonging to this specimen, is represented on Plate LXXla, fig. 8. It is a little smaller than that of Uncia concolor, and is quite similar in general proportions, especially in the form of the centrum. It differs in the following points: (1) The expanse of the postzygapophyses NIMRAVID^. 959 is a little less than the width of the centrum; in TJ. concolor it is a little greater. (2) The posterior edge of the neural spine is narrow and simple; in U. concolor it is wide and grooved. (3) There is no reverted process near the base of the diapophysis, as in U. concolor. (4) The metapophyses are more compressed, and rise higher than in U. concolor. As in the puma, there are no anapophyses. Measurevients of seventh lumbar vertebra. m. c vertical .- *^1^ Auterior lUameters of centrum { " ' .,. c transverse - "*' Length centrum on side - "30 Posterior diameters of centrum \ ' „ . ( transverse "">w Expanse of prezygapophyses at middle 0~5 The differences between this vertebra and the corresponding one of Uncia concolor are nearly those which distinguish it from the lion, leopard, and cheetah, with the following exceptions: In the lion the neural spine is thin behind, and the metapophyses thin and elevated, as in A. debilis. In the leopard the angle of the transverse process is not produced, and is more distal. The diapophysis in the cheetah is quite as in A. debilis, slender and without posterior angle. Portions of the scapula and of the fore and hind limbs of this specimen are represented on Plate LXXIw, figs. 9-1 G, The glenoid cavity of the former narrows forwards to a subacute apex, which is not truncate, as in the panther. The coracoid hook, if it were present (the specimen is injured), originated farther above this ape.x than in the panther, leopard, or common cat. The characters may be compared with those of the recent cats, as follows: TJncialeo. Coracoid nulimental; anterior tuberosity acute; posterior border of neck truncate; adjacent angle-ridge not continued. Arcludurus debilis. Anterior tuberosity acute; posterior bolder truncate and rugose for insertions; no adjacent angle-ridge. Uncia concolor. Coracoid distinct; anterior tuberosity truncate; posterior border of necli truncate and rugose for insertions. Unda pardus. Coracoid distinct; anterior tuberosity acute; posterior edge not trun- cate; no adjacent angle-ridge. Cyncehtrus jitbatus. Coracoid distinct; anterior tuberosity acute; posterior edge not truncate; adjacent angle-ridge not defined. ^elis domestica. Coracoid present, not separated by notch, and continuous with anterior tuberosity; posterior edge openly grooved on account of adjacent posterior angle-ridge. 960 THE JOHN DAY FAUNA. The head of the humerus presents some characters which distinguish it from those of the sjjecies of cats above mentioned, although it resembles them strongly in general features. While rather smaller than those of the panther and leopard, the greater tuberosity is more prominent, and the bicipital groove wider and deeper. The proximal surface of the lesser tuberosity is more distinct from the head, and is less decurved posteriorly. Viewed from the inner side its proximal surface is nearly straight and makes a right angle with the prominent posterior bicipital crest instead of being continuous with it, as in the panther and domestic cat, more nearly resembling the leopard and the lion. The tricipital fossa is larger than in any of those species, being well defined b}^ a strong ridge posteriorly. The fossa musculi teris is quite small, less than in the Uncia concolor and U. ho and Felis domesfica. The distal extremity of the humerus displays characters intermediate between those of the existing Felidce and the fiesh- eaters of the Eocene period. This is shown in its rather greater transverse extent; or, to particularize, in the greater length of the radial part of the trochlea and greater production of the internal epicondyle. The former has its proximal anterior border notched, and its face has a corresponding slight contraction not seen in any of the recent Felidce, but not quite as strong as that of the Crocuta brunnea and the Canidce. The distal extremity of the internal epicondyle is a truncate half-circle. Its production interior to this is withdrawn to a more proximal position. The olecranar fossa i& well marked, and has a slight perforation. The radial fossa is w^anting. The Jifth metacarpal is, relatively, smaller than in Uncke ho, pardus, and concolor, Cyncelurus jubatus and Fells domestka. It displays all the special characters of these species, including the keel-like interlocking process con- necting it with the fourth metacarpal, so characteristic of the FeUdce. The proximal extremity resembles that of the lion rather than that of the pan- ther in the plane surfoce of insertion of the external articular ligament. Measurements of fore limb, ji. Diameters of glenoid cavity of scapula I anteroposterior 0-J9 ( transverse at middle (_m {transverse, extreme 049 transverse to groove U33 through lesser tuberosity 036. NIMRAVID^. 96 1 M. ("transverse, extreme 044 _. ^ ,■,.,■, , „, 1 transverse of condyles 033 Diameters of distal end of humerus'; . . . . ji /«.« I anteroposterior, at flange 020 • (_ anteroposterior at middle of condyle 014 Length of fifth metacarpal 039 Transverse diameters I P'-°^i°'*^y 0"^ ( distally (epicondyles) Oil From the above measurements it may be seen that the fifth metacarpal bone is relatively only three-fifths as long as that of the recent Felidce above mentioned. The head of the tibia is about the size of that of a rather small adult Uncia concolor from Texas in my collection, and does not differ from it materially in characters. The anterior external tuberosity is not prominent, resembling that of Felis domestica rather than that of the larger cats. The external cnemial, and the popliteal fossae are more deeply excavated than in any of the five FelidcB above mentioned, and the external posterior angle is acute. The distal extremity strongly resembles the corresponding part in the recent species of Felidce, the external astragaline fossa being a little more expanded outwards. There is but one groove for the tendon of the peronaeus muscle instead of the two which are more or less distinct in all the species named ; and its anterior bounding crest extends to the distal border of the malleolus, as in Uncia concolor, and does not cease above it, as in the other Felidce above mentioned, and as in Canis lupus. The per- oneal ridge is well marked. The astragalus differs from that of all the Carnivora mentioned in this article in the shortness of its neck and the extension of the internal trochlear crest to the border of the navicular surface, from which only a narrow groove separates it. The trochlear face is a little narrower than in the species of Felidce and Hycenidce cited, and the inner side is more oblique outwards and downwards than in any of the species cited, excepting the Uncia concolor. On this side there is a well-marked tuberosity on the inferior margin poste- rior to the middle. Above and anterior to it the astragalus is concave. The navicular bone must have an extensive proximal external production, judging from the extent of the recurved external part of its facet on the astragalus. The trochlear groove of the astragalus is distinct, but is less profound than in the recent Felidce and Hycenidce. The first metatarsus is 61 c 962 THE JOHN DAY FAUNA. much shorter and more slender than that of Uncia concolor, U. pardus, Cyncelurus jubatus, or Crocuta maculata. What its length relatively to the other digits is, cannot be readily ascertained at present. Its proximal ex- tremity is formed much as in the recent Felicke and Eycenidce, except that there is scarcely any external angle, from which it results that the bone is narrower when seen from the front. The shaft is subcylindric, is distally somewhat flattened, and is gently bowed forwards. The epicondyles and extremital keel are well developed, and much as in the recent species. Measurements of posterior limb. M. {transverse 045 anteroposterior at middle I g^«"^t*«* "^"^ (least 020 Diameters of shaft at distal fourth ^ ^ '". .,„ ( anteroposterior 01b Diameters of distal end of tibia? "■ „,„ ( anteroposterior Oia _. , » i 1 < transverse at middle 024 Diameters of astragalus •; „„„ ( anteroposterior Vis Length of trochlea on external crest 029 Width of head 018 Length of first metacarpal 067 Anteroposterior diameter metacarpal V ^ % < distal 013 Width of shaft at middle 009 Width at epicondyles 013 Restoration. — It is probable from what has preceded, that the Archce- lurus debilis was an animal presenting much the appearance of the existing cats, and of about the size of the American panther. Omitting more tech- nical characters, it differed from this and other species of the Felidce in the greater slenderness of its feet. Its head was characterized by less breadth through the posterior part of the cheeks, and by a greater convexity of the forehead between the eyes, and a greater prolongation backwards of the same region. Its structure plainly indicates that this species was of less sanguinary habits than the exising Felidce, since its prehensile organs, both of the feet and dentition, are less robust. The slender zygomata and rami of the lower jaw show also that the impact of its bite was less powerful, although the large size and narrow form of the sectorial teeth furnish an effective cutting apparatus, which in some degree supplements the deficiency of strength. The weakness of the rami is further provided against by the curious exos- NIMRAVID^. 963 tosis at the base of the inferior sectorial ah-eady mentioned. This growth is symmetrical on the two sides of the skull, and is evidently normal; traces of it are seen in the species of Nimravus. History. — The first description of this species was given by myself under the head of the Nimravus hrachyops {Machcerodus brachyops. Pale- ontol. Bulletin 30, p. 10, Dec, 1878), from a skull found by Mr. Sternberg, under the impression that it might belong to a female of that species. Sub- sequently a nearly perfect cranium, obtained by Mr. Wortman, demonstrated the distinctness of the animal, both as to species and genus. I published a wood-cut of this skull in the American Naturalist for December, 1 880. Horizon and locality. — The remains of the Archcelurus dehilis have so far been only found in the Middle Miocene formation of the John Day River, Central Oregon. Judging from the remains, it was, after the Nimravm gomphodus, the most abundant feline of that region. NIMRAVUS Cope. Proceedings of the Philadelpliia Academy, 1879, p. 1G9. 3 1 3 1 Dental formula: I. -; C. -; Pm. -; M. -. Superior canines elon- gate, denticulate. Mandibular rami not flared downwards in front. Incisors with short subspatulate crowns. Superior sectorial without basal anterior lobe ; inferior sectorial with well developed heel, and no internal tubercle. No intermediate posterior lobes of the premolars. Postglenoid and post- parietal foramina present. This genus has the dental formula and characters of Hoploplioneus, with the addition of a tubercular inferior molar tooth. It is, moreover, not a true saber-tooth, as is that genus, since it does not display the inferior anterior flange of the mandible. This is represented by an obtuse angular border, quite as in the species of Archcelurus, in which genus Nimravus finds its nearest ally. The constant absence of the anterior premolars in both jaws distinguishes it sufficiently from that genus. On this account, and in view of the larger development and denticulated edge of the superior canine teeth, Nimravus may be considered as occupying a position between the two genera above named. Two species are known to me, a larger and a smaller, both from the Middle Miocene formation. 964 THE JOHN DAY FAUNA. NiMRAVUS GOMPHODUS Oope. American Naturalist, 18S0, p. 844. Bulletin U. S. Geolog. Surv. Terrs., 1881, p. 167. Nimravua brachyopa Cope. Proceeds. Phila. Acad., 1879, 170; uot Machcerodua hrachyopa. Proceeds, Amer. Philos. Sec, 1878, p. 72. Plates LXXIII; LXXIV, fifjs. 1-2. This feline is represented in my collection by parts of three individuals. The first includes a skull with one side and part of the other completely preserved, with the cervical and some dorsal vertebrge; the second is known from the posterior part of a mandibular ramus supporting three molar teeth; the third specimen embraces an entire mandibular ramus with all the teeth, and a femur, both having been found lying close together in the rock. The skull of the first specimen has the mandible attached, with the mouth partly open, as represented on Plate LXXIII. It is as large as the large forms of the panther, and exceeds slightly the skull of the Archodurus dehilis. It has very much the general proportions of that of the panther in the regular convexity of the profile of the frontal and nasal regions, the length anterior to the orbit, and in the degree of production of the inion. The length anterior to the glenoid cavity is relatively greater than in the panther, so that the mandible is longer. The front is moderately convex in transverse section, and is prolonged farther posteriorly than in the pan- ther, through the more gradual convergence of the borders of the tem- poral fossa, resembling in this the tiger rather than the other species of Uncia. The obtuse postorbital angle is more prominent than in the Archodurus dehilis, but does not deserve the name of a process, as it is- in the large recent cats. The side of the face in front of the orbit is gently concave ;^ in front of the foramen infraorhitale exterius it is nearly plane. The con- traction behind the orbits is about as in the panther. The zygomatic arch is quite as prominent anteriorly as in the recent cats, but at the middle of its course it is less convex or flatter, as in the Archodurus dehilis. The inion pro- jects beyond the vertical line of the occiput, but not so far as in the tiger or the Pogonodon platycopis. The occiput is not higher than wide above, and it is divided by a keel which fades out on the inferior third. The lateral crest is low above the paroccipital process, where it divides into two low ridges. One of these goes to the paroccipital process and the other to the base of NIMRAVIDJS. 965 the posttympanic, where it turns forwards and becomes the acute supra- meatal crest. The two tuberosities on the superior border of the foramen magnum are rudimeiital. The paroccipital process is directed posteriorly. It is acute and rather long, is convex behind and flat in front. The post- tympanic is short, and its extremity forms an obtusely rounded tuberosity. There is an osseous tuberosity below the meatus of the ear which is doubt- less the same as the piece in the Archceliiriis debilis which I identified with the tympanic bone. The basioccipital is divided by a median keel, while the basisphenoid is smooth. The palatal surface is injured in this specimen. The ramus of the mandible is longer, deeper, and more compressed than in the recent species of Uncia and the Pogonodon platycopis. It is more robust than in the Archcelurus debilis, and the exostosis below the last two molars is wanting. It is represented by a thickening of the external alve- olar border, which is larger in some specimens than in others. The inferior border is gently convex below the teeth, and rises slightly below the anterior part of the masseteric fossa. It is continued into the hooked angular pro- cess, which is as wide as deep,. and is not incurved. Anteriorly the inferior border is continued as an obtuse angle slightly everted but not in the least decurved below the diastema, and it then rises, running obliquely forwards and forming the obtusely angular border of the flattened symphyseal region. The inferior border of the symphysis descends below the level of the inferior border of the ranuis. The condyle measures half the distance between the angle and the summit of the coronoid process. The latter is wide and is obtusely rounded above, where it does not extend posterior to the vertical line from the condyle The masseteric fossa is deep and wide ; its narrow anterior border is reverted, while the inferior region is excavated abruptly below the general plane. There is a secondary fossa in its posterior part whose superior boundary marks half the distance between the last molar tooth and the summit of the coronoid process. Sutures. — The premaxillary bone rises in its narrow portion to the hori- zontal line of the superciliary border. The maxillo-frontal suture is regu- larly convex upwards, and its anterior extremity falls short of the premaxillo- maxillary suture by .008 m. The nasomaxillary extends farther posteriorly, i. e., to above the anterior third of the orbit, the palate and basioccipital 966 THE JOHN DAY FAUNA. being the horizontal base. The fronto-parietal suture is coarsely zigzag squamosal, and although it is entirely within the temporal fossa, it extends further forwards than in the recent cats. This extension is represented in the panther^ by some curious produced laminae, one on each side, reaching the frontal angle. The parietal and alisphenoid bones have an extensive contact. I do not find the large supraoccipital wormian bone of the recent large cats. ^ Foramina. — The foramen wfraorhitale anterius is rather large, is a vertical oval in form, and is presented forwards. Its external border is above the posterior lobe of the second superior premolar. The optic foramen is large, and is separated from the much larger / sphenoorhitale by a short interval. The/ rotundum is near the latter, but is entirely distinct from it; it is a little smaller than the/ oj)ticum, and larger than the/ ovale. The/ ovale is well anterior to the/ lacerum anterius. An alisphenoid foramen. The / post- glenoideum and/ caroficum are well defined; the latter is separated from the jugular, and this in turn from the condyloid foramen. The / postparietale is in the upper part of the inferior half of the parietal bone. There are no mastoid foramina. There are two lateral mentals, one below the anterior (third) premolar, and one below the diastema. The foramen magnum is large, and is wider than deep, as in Archcelurus debilis. Dentition. — The crowns of the superior incisors are flattened in front, where they have vertically oval outlines. The face of the external inci- sor is about twice as large as those of the others, and is bounded exter- nally by a considerable face of contact for the inferior canine. The superior canine is of peculiar form, and does not exactly resemble that of any known species of the family Felidce. The anterior border of the crown is a straight line from a point near the base to near the apex. The posterior outline is also nearlj^ straight, having a slight concavity near the base and a slight convexity near the apex. As the anteroposterior diameter at the base is not large, and as the length of the crown is considerable, the result- ing form is peculiarly slender and pike-shaped. The external face is strongly convex anteriorly, turning into a transverse anterior face, which is separated from the inner face by a right-angled ridge. Next to this ridge on the basal 1 1 find it in skulls whict I have examined. NIMEAVID^. 967 half of the crown, excepting near the base, the anterior face is thrown into a shallow groove. The ridge is not denticulate, while the acute posterior edge of the tooth is distinctly so from the base to the apex. The (first) second superior premolar is very small, and is two-rooted; it is a little nearer the base of the third premolar than that of the canine, leaving two diaste- mata. The third premolar is of large size, and consists of a triangular cusp and a short lobe-shaped acute heel. The superior sectorial is rather large. The apex of its anterior cusp is directed well backwards, and its posterior border is acute. The heel is long, and its cutting edge rises to half the height of the cusp. The external extremity of the crown of the tubercular molar is narrower than the internal; it just reaches the vertical plane of the alveolar border of the maxillary bone. Its size is moderate. The inferior incisors are smaller than the superior, and of similar form. The external is only a little larger than the othei's. The inferior canine is much larger, and is nearly half the length of the superior canine. Its crown is directed somewhat outwards, and its inner face is moderately beveled above the apex of the external incisor. A section of the crown is an oval whose long axis is anteroposterior at the base, and more inwards posteriorly to an angle higher up. This angle is the posterior cutting ridge, which extends from the inner side of the base to near the apex, and is strongly denticulate. The diastema following the inferior canine is remarkably long in this species, relatively longer than in any of the large existing cats. The third inferior pi'emolar (first present) is also remarkable for its large size, differing in tliis respect from true cats and saber-tooths alike. Its cusp is elevated, and the posterior basal heel is very short. There is no anterior basal tubercle. The fourth premolar has a greater longitudinal extent, and its apex is not quite so elevated as that of the third. Its anterior and pos- terior basal lobes are trenchant, and of equal anteroposterior extent. The inferior sectorial is large, and its principal lobes are large, and with acute cutting edges. Tlie anterior lobe is longer than high, and the posterior higher than long, and its posterior edge is acute. The heel is small and acute. There is no trace of internal tubercle. The tubercular molar is small, and its diameters are subequal, and similar to that of the heel of the sectorial. In one of the three mandibles in my collection, represented on Plate LXXIV, fig. 1, this tooth is wanting. 968 THE JOHN DAY FAUNA. The enamel is smooth, excepting on the superior canine and the an- terior part of the anterior inferior premolar. Here it is roughened by minute impressed punctae. No cingula. Measurements of skull. a. Axial length from occipital condyles to iiremaxillary border 206 Axial lengtli from inion to premaxillary border 220 Axial length from premaxillary border to canine tooth - 017 Axial length from premaxillary border to anterior border of superior sectorial 066 Axial length from premaxillary border to posterior extremity of maxillary bone 097 Axial length from premaxillary border to postglenoid process 162 Length of nasal bone from nasal notch - 065 Length of sagittal crest from inion 082 Width of premaxillary bone (greatest) 019 Width of each nasal bone at middle 008 Width of each frontal bone at middle of orbit 028 Width of each frontal bone at postfrontal angles 035 Width of skull at anterior part of zygoma 098 Width of zygomata at temporal fossa Ill Width of skull at meatus auditorius 074 Width of skull between apices of paroccipital processes 054 Width of occiput at middle 044 Width of foramen magnum 024 Elevation of occiput above fsramen 036 Widthofchiuat base 022 Width of chin at summit 028 Depth of chin 040 Depth of ramus at diastema 027 Depth of ramus below last premolar 031 Length of ramus 157 Elevation of condyle • 033 Elevation of coronoid process • 071 Length of superior canine 045 Diameters of base of superior canine J ^ < transverse W)a Anteroposterior diameter at middle 010 Distance from canine to third premolar 016 Length of molars, including third premolar 045 Length of base of third premolar 018 Elevation of cusp of third premolar 013 Length of base of sectorial 025 Elevation of cusp of sectorial - 015 Width of tubercular '. 009 Elevation of inferior canine - 024 Anteroposterior diameter of inferior canine at base — 012 Length of inferior diastema 022 Length of inferior molar series - -- 063 Length of third premolar 0175 Elevation of third premolar 0175 Length of fourth premolar 020 Elevation of fourth premolar 015 Length of sectorial 025 Elevation of median cusp of sectorial 016 NIMEAVID^. 969 The cervical vertebrce have about the size and i^roportions of those of the leopard and the panther, differing only in minor respects. The centra are moderately depressed, and have oblique articular extremities, but the obliquity is rather less marked than in Uncice ho, concolor or pardus, or Felis clomestica. All are perforated by the vertebrarterial canal, excepting the sixth, as usual. The transverse processes of tlie atlas are about as wide as in the species named, but are more contracted at the base. The latter is pierced posteriorly, and in the middle inferiorly, by the vertebrarterial canal. The neural arch of the axis is more elevated in front than in the recent large cats, so that the interspinous foramen is larger. The axis also differs from the recent species in having the posterior borders of the arch above the zyga- pophyses regularly concave, and not filled ( U. leo, F. domestica) or interrupted (U. concolor, U. imrdus) by the opisthapophysis. The neural arch has the median posterior prolongation usual in Felidce. The transverse process is acuminate, and extends as far posteriorly as the vertical line of the post- zygapophyses. The hypapophysial keel of the axis is weak, but a little stronger than in the lion. The other cervicals can scarcely be said to be keeled, though traces are present on some of the centra, which on the third, fourth, and fifth, spread out posteriorly into triangular areas. Opisthapo- physes are only present on the third and fourth cervicals. In the recent species I find them present, as follows: Nimravus gomphodus, 3-4 ; Unda leo, 2-3-4-5-6-7 ; Uncia concolor, 2-3-4-5 ; Uncia pardus, 2-3-4-5-6-7 ; Cyncelurus jubatus, 2-3-4 ; Felis domestica, 2-3-4-5-6-7. All the cervicals behind the third have well-developed neural spines, that of the seventh covering the entire length of the neural arch by its base. The transverse processes present some peculiarities. The principal feature is the greater prolongation downwards of the diapophysial element, and hence less separation from the parapophysial than in the species above mentioned, especially in the fourth and succeeding vertebrae. The para- pophyses have considerable expanse both transversely and fore-and-aft. The first and second dorsal vertebrse differ from those of all the Felidce 970 THE JOHN DAY FAUNA. above mentioned, in having the superior half of the posterior face of the neural spine grooved. The inferior half has a keel, which becomes very prominent to a point opposite the commencement of the zygapophyses and then suddenly subsides, as in U. concolor. The postzygapophyses are recurved outwards on the first dorsal ; on the second they are plane, and slope downwards outwards. The center of both are as long as those of the last cervicals, are depressed, and have two weak angles on the inferior face. Measurements of vertebrae. M. Length of cervical vertebrae 200 Transverse extent of atlas 090 Transverse extent of transverse process of atlas 025 Length of centrum of axis on side 022 Elevation of centrum and neural canal of axis anteriorly 029 C anteroposterior 025 Diameters of centrum of fourth cervical < vertical in front 012 ( transverse in front 020 Transverse extent with processes 054 ( anteroposterior 024 Diameters sixth cervical < (vertical .013 i posterior^ ^ I transverse 026 Diameter with transverse processes .050 Expanse of prezygapophyses 035 c anteroposterior 022 Diameters centrum first dorsal < , J vertical 013 ( ( transverse (without rib facets) 017 E'evation of neural canal in front Oil Elevation of neural arch and spine 055 Expanse of postzygapophyses : . . .025 Expanse of postzygapophyses second dorsal 022 Expanse of diapophyses second dorsal 050 Anteroposterior diameter neural spine at base 017 These vertebrae are represented in PI. LXXIIa, fig. 3. The second specimen of the Nimravus gompliodus consists of the pos- terior part of a mandibular ramus supporting teeth. Its dimensions are a little smaller than those of the type. The third specimen includes a complete mandibular ramus with all the teeth, some dorsal vertebrae, and a femur. These pieces wei'e found in juxtaposition in the same block of stone, and agree iu proportions. The specimen was as large as No. 1. The left femur is perfectly preserved, and is represented in Plate LXXIV, fig. 2. It is rather long and slender, hav- ing nearly the size and proportions found in the leopard and panther. Its little trochanter is more prominent than in either of those species, and the NIMEAVID^. 971 trochanteric fossa descends lower down. The fossa ligamenti teris communi- cates with the neck by a groove, a character not seen in any of the five recent species at my disposal. The external linea asper forms a prominent ridge on the proximal half of the shaft, while the internal linea asper is short and only prominent proximally. Distally, the external rotular crest extends farther posteriorly than the internal. The rotular surface is a little narrower than in TJncice leo, concolor, or pardus, and while as naiTow as in Felis domes- tica and Cyncelurus juhatus, is prolonged farther posteriorly. The lower portion of the shaft is oval in section. The intercondylar fossa is divided into three areas, viz, an anterior and posterior subtriangular separated by a deep oblique fossa. The former are the points of insertion of the intei'nal and external crucial ligaments. The fossa between them is characteris- tically much deeper than in any of the recent feline animals above men- tioned. Measurements of femur. M. Total length 260 / at proximal extremity 052 Transverse width < at distal extremity 046 ( at middle of shaft 023 {of head 024 of great trochanter 027 of shaft 018 of condyles 045 Width of rotular face at middle 020 Mestoration.— The Nimravus gomphodus is as large as the full-grown panther of the large varieties. It probably stood as high above the ground, but whether the body had the elongate proportions of that animal, or the more robust form of the leopard and jaguar cannot be ascertained in the absence of necessary material. Unless the animal had pendulous upper lips, a thing unknown among cats, the superior canine teeth must have been distinctly displayed on each side of the chin, their points de- scending entirely below the lower margin of the lower jaw when the mouth is closed. As these points are less compressed than in the true saber-tooths, they were less liable to fracture from lateral blows, but were more apt to be broken by fore-and-aft strains, owing to their slenderness. The long canines of this species testify to bloodthirsty habits, for as weapons for penetrating wounds they are withovit rival among carnivorous 972 THE JOHN DAY FAUNA. animals. They resemble considerably the teeth of some of the Dinosauria; for instance, those of the Triassic Clepsysaurus. The sectorial apparatus is especiall}^ effective, and no tissue could long resist the combined action of the opposing blades of the two jaws. Nevertheless, this species did not, probably, attack the large Merycochoeri of the Oregon herbivores, for their superior size and powerful tusks would generally enable them to resist an enemy of the size of this species. They were left for the two species of Pogonodon, who doubtless held the field in Oi-egon against all rivals. The compressed mandibular rami of the Nimravus gompJiodus, though less slender than those of the Archcelurus debilis, are not so well calculated to resist lat- eral strains as the more robust jaws of the majority of the existing Felidoe. History. — The first notice of this species was based on a mandible. As it is exceptionally without tubercular tooth, I referred it to the genus Hop- lophoneus; and since its proportions are very similar to those of the Pogonodon brachyops, of which no mandible had been found up to that time, I identi- fied it with that species. The reception of other specimens enabled me to distinguish the genus Nimravus, but it was not until some time later that I became satisfied that it was distinct from the species to which I originally referred it. The reasons for this conclusion are given under the head of Pogonodon hrachyops. Nimravus confertus Cope. Bulletin U. S. Geol. Survey Terrs., VI, p. 172, Feb., 1861. American Naturalist, 1880, p. 849, fig. 10. Plate LXXI a; lig. 17. This species is as yet represented by a mandibular ramus only. It is one-third smaller than that of N. gompliodus. The inferior border of the ramus is broken off, excepting for a space belowthe diastema. The general form is narrow, as in N. gompliodus, and there is a projecting ledge along the inner base of the sectorial similar to that seen in the latter species. The angle separating the side from the front of the ramus is rather stronger than in N. gompliodus, but there is no indi- cation of an inferior flare. The diastema is shorter than in the ty]Dical species, its length equaling that of the base of the third (first) premolar; in N. gompliodus it is half as long again. The symphysis is correspondingly, shorter, ceasing a little in advance of, and at the posterior border of, the NIMEAVIDiE, 973 inferior canine tooth, while in N. gomphodus it continues for one diameter of the canine behind its posterior border. The crown of the inferior canine tooth is directed backwards, and its serrate cutting edge is presented almost entirely inwards. The interno- anterior face of the crown is flat, and has a low shoulder at the base. The molars have the proportions of those of N. gomphodus, differing only in their smaller size, which is very apparent, as can be seen by the measure- ments. The first (third) premolar is a little longer on the base than high, has no anterior tubercle, and has a short cutting basal heel. The fourth premolar has subequal anterior and posterior basal cutting lobes, and the base is longer than the elevation of the median cusp. The sectorial tooth has a short cutting heel, but no trace of inner tubercle. The anterior lobe is as long as the median, but not so high. It overlaps the fourth premolar as far as the base of the median cusp. No incisor teeth are preserved in the specimen. Tubercular small. Meas^irements of ukull. M. Depth of ramus at diastema 020 Depth of chin 027 Elevation of inferior canine 016 Diameter of inferior canine at hase 010 Length of inferior diastema 014 Length of inferior molar series 053 Length of third premolar 014 Elevation of third premolar 010 Length of fourth premolar 016 Elevation of fourth premolar 013 Length of sectorial 022 Elevation of median cusp of sectorial 015 Although a left mandibular ramus is all that I have been able to obtain of this cat, the evidence is sufficient that it is specifically different from the others enumerated in this chapter. It is inferior in size, and peculiar in the reduced symphysial and incisive parts of the mandible. It was found by Mr. Wortman in the bad-lands of the John Day Valley, Oregon. DINICTIS Leidy. Proceed. Philada. Academy, 1654, p. 127. Extinct Mammalia of Dakota and Nebraska, 1869, p. 64. With this genus we enter tlie group of the primitive saber-tooths, com- mencing with the most generalized form. The skeleton is yet unknown, 974 THE JOHN DAY FAUNA. but the skull and dentition are those of a true saber-tooth, and there seems, to be no ground for believing the Musteline affinities suggested by Leidy.^ It occupies the lowest position on the line of the saber-tooths, on account of its numerous and simply constructed molar teeth, and stands in immedi- ate connection with the false saber-tooth group, having exactly the dental formula of ^lurogale Filh. On this account I formerly united the two genera, but now believe that the absence of the inferior flange of the man- dible in ^lurogale is sufficient ground for maintaining them as distinct. The latter genus, in this respect, exactly resembles Archcelurus and Nimravus. Remains of this genus are quite abundant in the White River forma- tion in Nebraska and Colorado. They principally belong to the longest known and typical species, D. felina Leidy. Specimens are much less numerous in the John Day beds of Oregon. Two species have been obtained from the former horizon, the D. felina and D. squalidens, and one from the latter, the D. cyclops. The characters are as follows: 3 1 3 ] Dental formula: I. -; C. -; Pm. -; M. -. The superior canine is long and compressed, and reposes against an inferior marginal flange of the mandible, whose surface is separated from that of the symphysis by a strong angle. Unworn incisors with wedge-shaped crowns. Superior sec- torial without anterior basal lobe. Inferior sectorial with posterior cutting heel, and an inner tubercle of small size. Postglenoid and postparietal foramina present. No intermediate posterior lobes of the premolars. The three species may be distinguished by the following characters: First inferior molar two-rooted; first superior very small; cranium shorter behind. D. cyclops. First inferior and superior molars two-rooted, the latter larger; cranium longer behind D. felina. First inferior molar one-rooted; mandibular flange short, rounded D. squalidens. DiNicTis CYCLOPS Cope. Proceedings Academy Philadelphia, lt-79, 176 (read July 8). American Naturalist, 1880, p. 846, fig. 8. Plate LXXV ; fig. 1. The profile of the skull is very convex, the planes of the nasal bones and sagittal crest meeting at an angle of 135°. The place of the angle is 'Extinct Mammalia, Dak., Nebr., p. 64. NIMRAVID^, 975 occupied by the regularly rounded posterior frontal region. The postorbital angle is exactly half way between the inion and the anterior edge of the premaxillary bone. In the D. felina, according to Leidy's figure, which I find to agree with the specimen which it i-epresents, the last-named distance is equal to the space between the postorbital angle and the postparietal foramen. Thus the region covered by the temporal fossa is shorter in the jD. Cyclops. The front is also convex transversely, excepting where it is inter- rupted by a median longitudinal shallow open groove. The postorbital angles are quite prominent, are subacute, and have a triangular section. They mai-k lateral angles equidistant between the apices of a diamond- shaped space, the posterior angle being the junction of the temporal ridges, and the anterior being theoretically situated between the anterior extremities of the frontomaxillary sutures. The nasal bones are shortened in front; their lateral angles are but little produced, and their anterior borders are concave. The premaxillaries rise high on each side of the nasals, but do not reach the frontals. The face is flat in front of the orbit, and the sur- face is roughened for a space just in front of its border. The zygomatic arches are strongly convex, but somewhat flattened medially, and a little more expanded posteriorly than anteriorly. They are less slender than in Archcelurus deh'dis and Nimravus gomphodus, but their postorbital angle is not larger, being a mere angle. The brain-case is rather large, and is sep- arated from the frontal region by a moderate constriction. The inion does not project so far posteriorly as in some of the cats, and the occiput is higher than wide, and is divided in its superior third by a weak median keel. The paroccipital process is small and acuminate; it is directed poste- riorly opposite the superior part of the occipital condyle. An obtuse ridge proceeds downwards and forwards from its base, and terminates in the posterior angle of the posttympanic process. The lateral occipital crest is continued as a delicate ridge into the external angle of the posttympanic process. The latter is well below the paroccipital; it is directed down- wards, ceasing opposite the middle of the posterior face of the zygoma. Its extremity is truncate and triangular, the apex of the triangle being ex- ternal. The suprameatal border is prominent and thin, and the inferior border of the meatus is the deeply set border of the bulla. 976 THE JOHN DAY FAUNA. There are two areas of insertion on the basioccipital bone, separated by a low median keel, and extending anteriorly as far as the front of the otic bulla. Each is interrupted in front of the middle by a rugosity. Basi- sphenoid flat. The otic bullae fit the adjacent bones closely, so as to close everything but the foramina. The pterygoid alae are well produced down- wards. The palate of Dinictis Cyclops is flat ; and is, at the widest part, as wide as long. The posterior border of the palate forms two concavities, uniting medially in a slight angle. Thus the form is that of the lynx and the leopard, and different from the panther, tiger, and jaguar. The forms of the palates of these animals are as follows : I. Two deep excavations separated by a point: Moplophoneus oreodontis ; and if. cerebralis. II. Two shallow excavations, separated by an angle: Felis domestica; Unciapardus; Lynxrufus; Moplophoneus oreodontis ; Dinictis cy clops ; Procelurus julieni. III. A regular shallow concavity: Archcelurus debilis ; Uncia tigris. IV. A deeply excavated concavity : Uncia concolor. V. A triple concavity ; two lateral, separated by a deep median notch : Uncia onea. The mandible is compressed, but is rather low at the front of the masseteric fossa. It is more robust than in the known species of Archcelurus and Nimravus. The inferior anterior flange is well marked and compressed. It is short, but not so broadly rounded as in D. squalidens. The anterior symphysial face is flat and deep, and the incisive border elevated. Sutures. — The frontomaxillary suture rises from the anterior border of the orbit, and then extends, with some irregularity, horizontally to the frontonasal suture, as described by Leidy in the D. felina, and not descend- ing, as in Nimravus hracliyops. The lateral nasal sutures are very little convex outwards posteriorly, and form a segment of a circle posteriorly. The frontoparietal suture is obliterated, but the superior squamosal suture does not reach it. The premaxillo-maxillary suture of the palate incloses a triangular space. Foramina. — The foramen infraorhitale exterius is very large, is subtrian- gular, and is directed forwards. Its posterior border is above the anterior border of the superior sectorial tooth. The incisive foramina extend to a point a little behind the middles of the superior canines. The / / palatina are opposite the cusp of the third premolar. There is no alisphenoid fora- NEVrRAVID^. • 977 men. The oval / lachrymah is of medium size. The / opticum is far pos- terior and close to the / sphenodrbitale, which has twice its vertical diameter. On account of the early connection between the temporal and pterygoid parts of the sphenoid, the / sphenodrbitale and rotundum are thrown together and forwards. They are, however, completely divided. A narrow alisphe- noid canal enters the / rotundum from behind, connecting it with the / ovale. The / ovale is large and transverse. The / lacerum anterius is sub- round and rather large. The / postglenoideum is rather small, and is in the anterior wall of the meatus auditorius externus. On the posterior border of the bulla otica are two foramina; an external lai-ger, and an internal smaller. The latter occupies the usual position of the jugular foramen, but is proba- bly the / cnrotideuni. The other may have carried a branch of the jugular vein, although it is in the position of the stylomastoid foramen. The ante- rior condylar foramen is small, and is situated far posterior to the two foramina '«just mentioned. A small foramen just above the paroccipital process I suspect to be the mastoid. The postparietal foramen is large, and is situated below the middle of the parietal bone. The / magnum is wider than deep, and has a i-egularly arched superior border, without tuberosities. Dentition. — The superior canine is quite long, and has a regularly lentic- ular section, without facets. Its anterior and posterior edges are denticu- late. The external incisors are much larger than the internal, and have subconic crowns. The crowns of the others are subcuneiform. The first superior premolar is very small, much less developed than in D. felina. I originally described it as having one root, but there are indications of a second in an obsolete alveolus, filled partly by bone and partly by remains of the root. The tooth is lost from both sides of the specimen. The second premolar has a distinct anterior tubercle on the inner side, a character not seen in D. felina; the anterior angle of the sup,erior sectorial is more pro- duced than in that species. The crown of the supjerior tubercular looks partly inwards, is rather long, and has three roots. The inferior canines are considerably larger than the incisors. The latter are regular, and do not overlap each other. The second and third inferior premolars have well- developed basal lobes anteriorly and posteriorly. The heel of the sectorial is well developed. The tubercular is very small, and has a semiglobular m c 978 * THE WHITE EIVEE FAUNA. crown. It is present on both sides of the specimen. The enamel of all the teeth is smooth. No cingula. Measurements. M. Length of skull on base 140 Width of skull, measured below Ill Length of palate 060 Width of palate between posterior angles of sectorials 062 Width of iialate between canines 026 Length of skull to front of orbits (axial) 050 Vertical diameter of orbit 031 Interorbital width (least; 045 Elevation of inion from foramen magnum 032 Length of inferior molar series 050 Length of inferior sectorial 018 Length of base of inferior first premolar 055 Depth of ramus at sectorial 016 Depth of ramus at first premolar 021 Depth of ramus at flange 026 From the Miocene beds of John Day River, Oregon. Found by J. L. Wortman. This species was as large as the fully grown Canada lynx. Although of an inferior position in the system of Carnivora, its powers of destruction must have excelled those of the catamount. While the skull is generally less robust, its sectorial teeth are not smaller nor less effective than those of that animal, and the canines far excel those of the li^ang sjjecies as instru- ments for cutting their prey. DiNiCTis FELiNA Leidy. Proceedings Academy Philadelphia, 1854, 197; 1S56, 91; 1857, 90. Extinct Mammalia Dakota and Nebraska, 1869, p. 64 : Plate V, figs. 1-4. This species, whose dental and cranial characters have been described by Leidy, is known from a number of crania and jaws. The former differ in their ^proportions from those of the D. cyclops, having a relatively longer cerebral and shorter facial part of the skull. The anterior premolar teeth, especially in the upper jaw, were stronger than those of D. cyclops. I introduce the D. felina here for the purjwse of mentioning its geo- graphical range. Since the original specimens were brought from Northern Nebraska by Dr. Hayden, I have obtained a mandible from Northeastern Oolorado, and the Princeton Scientific Exploring Expedition procured part NIMEAVID^. 979 of a skull from the same region. The examination necessary for this deter- mination was kindly permitted me by Professor Guyot. The Colorado mandible differs from that of the D. squalidens from the same locality in having a shallow symphysis; that is, it descends but a shoi't distance below the inferior anterior mental foramen. The roots of the first inferior premolar are well separated. The third (fourth) has a well- developed anterior basal tubercle. DiNICTIS SQUALIDENS Cope. Proceedings Academy Philadelpliia, 1879, p. 176. Daptopkilus squalidma Cope, No. 16, p. 2 (August 20, 1873). Annual Report U. S. Geol. Survey Terrs., 1873 (1874), p. 508. Plate LXVIIa; figs. 15-16. Two mandibular rami belonging to two individuals represent this species. The one on which the species was proposed is immature, with the sectorial tooth partly protruded (fig. 15), and the tubercular invisible. Having failed to find any trace of the latter in the jaw, I proposed to regard the species as typical of a genus distinct from Dinidis, remarking at the time that should such a tooth be ultimately found, the genus would have to be abandoned. Evidence of the existence of this tooth was after- wards obtained. Still later, another saber-tooth was found with precisely the formula supposed to characterize this discarded genus {Daptophilvs). Under the circumstances I thought best to give the former a new name, Pogonodon. In this species the first lower molar tooth has but one root, while in the others there are two. The canine tooth of the typical specimen has also a very peculiar form. The crown is short and wide, like that of a Carcharodon shark, or somewhat like that of the saber-tooth Drepayiodon latidens Owen. As the first true molar tooth of this specimen was not fully protruded, it is possible that this canine belongs to the deciduous series. The jaw of the adult specimen contains parts of the alveoli of but two inferior incisors; the existence of a third is very doubtful. The canine is larsre and is directed outwards. Its crown is lost. The diastema descends, and is short, not exceeding in length the length of the base of the anterior lobe of the sectorial. The alveolus of the root of the first (second) pre- 980 THE WHITE KIVER FAUNA. molar is elongate anteroposteriorly, and has a very slight median constric- tion, indicating traces of opposite grooves on the root. The alveolar border is lost at the base of the third premolar, but from the remains of its alveoli it was not much smaller than the fourth. The fourth premolar has lost its cusp; it has a well-developed trenchant basal anterior lobe, not so large as in the known species of Archcelurus and Nimravus. The base of the secto- rial is absolutely and relatively shorter than in the specimens of D. felina figured by Leidy. The portion anterior to the heel is equal in anteropos- terior extent to the fourth premolar; it is longer in the specimens above mentioned. The alveolus for the tubercular molar indicates a larger tooth than that of the D. cyclops. The flange of the ramus is prominent, but short and rounded, extend- ing but little below the symphysis, which itself is continued considerably below the inferior anterior mental foramen. The superior anterior mental foramen is below the middle of the symphysis. The anterior external mental foramen is below the" anterior part of the alveolus of the first pre- molar. The ramus is quite robust, and is convex on both faces below the sectorial. The masseteric fossa is deep, but with sloping borders in front and below. A gradual rise towards the coronoid process begins on the inner side, at the posterior base of the sectorial. Measurements. 11. Length of entire dental series 064 Lengtli of molar deutal series 043 Length of diastema 008 Length of base of Pm. ii 005 Length of base of Pm. iv .'013 Length of base of .sectorial 017 Height of anterior lobe of sectorial. T 010 Long diameter of base of crown of inferior canine 009 Depth of symphysis , 025 Depth at flange 025 Depth at front of sectorial 017 Width of front of sectorial 007 Width of front of symphysis 012 The immature specimen is instructive in displaying the last two de- ciduous molars, with more of the crown of the sectorial than is seen in the other specimen. The latter shows the short trenchant heel, and the internal tubercle, which is on the posterior edge of the middle lobe of the crown,. NIMEAVID^. 981 about half way above the base, and a very Httle inside of the line of the edge of the heel. Its base is a little longer than that of the other specimen. The penultimate deciduous molar has equal anterior and posterior basal cutting lobes The median cusp is higher than the length of its own base. The last deciduous tooth is a sectorial; its anterior lobe alone remains. The entire crown of the superior canine was found with this lower jaw (see fig. 15 a 6). Its crown is quite short and compressed, and both edges are denticulate. It is probable that it is the temporary canine. It is much shorter than the permanent canine of any North American species. 3Ieasiirements. M. LeQgtli of base of deciduous penultimate molar 010 Elevation of cusp C07 Elevation of anterior cusp of last deciduous molar 007 Length of permanent sectorial 018 Length of base of crown of superior canine OH Elevation of crown of superior canine 025 The adult jaw above described differs from that oiD.felina in the con- siderably shorter tooth-line, as well as in the single-rooted first premolar. As compared with Leidy's figures, it is shorter than one of them by the length of the tubercular tooth ; and shorter than the other by the length of that tooth plus the heel of the sectorial. Both specimens were found by myself in the beds of the White River formation at a single locality in Northeastern Colorado. With them wei'e associated a multitude of jaws and bones of Marsupialia, Carnivora, Bo- dentia, Ungulata, Reptilia, etc. POGOXODON Cope. American Naturalist, 1S."?0, p. 143, (publishod January 31). 3 1 3 1 Dental formula: I.-; C. -; Pm. -; M. -. Inferior border of mandib- o 1 3 1 ular ramus flared downwards in front; lateral and anterior faces of ramus separated by a pronounced angle. Superior canine compressed, with ante- rior and posterior cutting edges. Superior sectorial without anterior basal lobe; inferior sectorial with a heel. No tubercular molar. No lobes on the edges of the crowns of the premolars. Incisors with conic crowns. Postglenoid and postparietal foramina present. 982 THE JOHN DAY FAUNA. This genus i-epresents a station on the line connecting Binictis with the higher saber-tooths, being intermediate between the foi-mer genus and Hop- loplioneus. It lacks the tubercular inferior molar of Dinictis, and possesses the second inferior premolar characteristic of that genus, which is wanting in Hoplophoneus. One species is certainly known, and a second is provis- ionally referred here. The two are the largest of the saber-tooths of North America, the type, P. plaUjcopis, equaling in dimensions the largest species of Drepanodon, being only exceeded among the tnie saber-tooths by the species of Smilodon. Unfortunately, only the skull of the typical species is known. Several bones of the P. hraclujops have been discovered. Fig. 38. — Poyonodon platycopis, less than two-tit'ths natural size. Mus. Copo. POGONODON PLATYCOPIS CopC. American Naturalist, 1880, ji. 143. Iloplophoneus j'lali/copis, American Naturalist, 1879, p. 798a, Decem- ber. Proceed. Amer. Philo. Soc, 1879, p. 373 (December 24). Plate LXXIV a. Tlie skull on which this species was established remains a vmique. It is in good preservation, not wanting any important part. The median por- tions of both zygomata are wanting, and the frontal region is crushed and parts of it weathered away. The cranium is characterized by the relative elongation anterior to the sagittal crest, the latter being a little more than one-third the length of the skull from its posterior apex to the premaxillary border, and equal the dis- tance from tlie junction of the temporal ridges to the anterior rim of the orbit. NIMEAVID.E. 983 The sagittal and frontal planes make an angle with each other much as in the recent cats of large size. The brain-case is relatively smaller than in any of the Felidremolar is larger, and has an anterior basal cutting tubercle, which is shorter than the cutting heel. The sectorial is small for the size of the skull, and its cusps are robust. The heel is short and thick, and has the peculiarity, entirely unique in the family, of a flat grinding surface. Measurements of skull. ■^ M. Length from iuiou to iiremaxillary border 280 Length from inion to chin WO Length from premaxillary border to superior canine 019 Leugtli from premaxillary border to line of orbit 090 Length from premaxillary bone axially to end of maxillary bone 096 Length from inion to occipital condyle (horizontal) 048 Length from inion to postglenoid process 113 Length from inion to furcation of temporal ridges ll.'j Width of zygomata (estimated) 192 Width of occiput at middle 037 Width of occiput at condyles 056 Width of foramen magnum 025 Width between posttympanic processes 074 Width of chin at base of symphysis 040 Length of mandibular ramus 177 Height of chin medially 050 Height of chin at flange 048 Height of ramus at Pm. iii 035 Height of ramus at M. i 030 Height of ramus and coronoid process 075 Length of superior dental series including canine 090 Long diameter of base of canine 026 Restoration and liabits. — As the greater part of the skeleton of the Pogo- nodon platycopis is unknown, little can be said as to its general proportions. The skull is one-sixth shorter than that of the usual size of the tiger (Uncia tigris), and is equal to the largest Brazilian variety of the jaguar, and is considerably larger than the Texan form of that species. The development of the dentition is concentrated in the canine teeth, and the powers of destniction of the animal would seem to be dispropor- tioned to its ability to appropriate its prey as food. The molar teeth are rather small, as is the case with the earliest representatives of the canine family. The inferior sectorial is primitive and peculiar in its robust heel. We can suppose this species to have been a great destroyer of contemporary NIMEAVIDJE. 987 mammalian life, and that the largest ungulates of the John Day fauna were its victims. History. — Science has hitherto had httle knowledge of this species, and owes what is here recorded to a fortunate chance. The exploring party which I had sent into the John Day River valley under the direction of Mr. Jacob L. Wortman, in 1879, examined the bad lands in the locality known as The Cove. In passing the bluffs on one occasion, a member of the party saw on the summit of a pinnacle of the crag what appeared to be a skull. The large .shining objects supposed to be teeth attracted his atten- tion, and he resolved to obtain the specimen. He, however, was unable to climb the cliff, and returning to camp narrated the circumstance. The other men of the party successively attempted to reach the object, but wei'e compelled to descend without it, and in one case, at least, the return was made at considerable peril. A later attempt, made by Leander S. Davis, of the party, an experienced collector, was more successful. By cutting notches with a pick, in the face of the rock, he scaled the pinnacle and brought down the skull, but at considerable risk to limb and life. POGONODON BRACHYOPS Cope. American Naturalist, 1880, p. 849, fig. 11 Machccrodus brachi/ojys Cope (partim). Paleontologioal Bul- letin Xo. 30, p. 10, 1878 (December 3). Proceedings American Pbilosopbical Socifity, 1878, 72. Plates LXXIV b ; LXSIV ; figs. 3-10. ..V This species is the second in size of the cats of the Truckee Miocene epoch. It is represented in my collection by a fragmentary skull of one individual, and by the maxillary bone and several bones of the skeleton of a second. The skull first mentioned includes the left side of the face, a part of the front, and the posterior regions, lacking one temporal bone. The maxillary bone is broken off at the infraorbital foramen, and the teeth are broken off. The following characters are noteworthy. The fronto- maxillary suture is transverse from the orbital border, and then tiii'ns slightly upwards rather than downwards as is usual. It most resembles the form in Dinictis cydops. The face is slightly concave in front of the orbit, and is marked by an impressed fossa immediately anterior to the orbit, of about the size and form of half of the end of the human thumb. In front 988 THE JOHN DAY FAUNA. of the infraorbital foramen the face is gently and regularly convex to the premaxillary border. The premaxillary ascending ramus is long, but does not appear to reach the froutomaxillary suture. The fragment of the front shows that the temporal ridges converge gradually, and that the middle line is concave. The posterior part of the skull shows a high sagittal crest and inion, and a brain case of the absolute size of that of the P. platycopis, and therefore relatively larger. The inferior part of the lateral occipital crest is obsolete, continuing into a low rounded ridge which is continued as the prominent superior border of the meatus auditorius externus. A posterior ridge goes to the external superior base of the paroccipital process; another ridge extends from the internal superior base, and the space between is divided by a median ridge. The paroccipital itself is short and is directed backwards. A perpendicular ridge descends from its external base to the posterior angle of the posttympanic process. The latter has a truncate downlooking extremity of a triangular form; the longest side being ante- rior, and the internal and external angles of about equal length. The occipital condyles are rather small. Foramina. — The / infraorhitale is large. So is the / postparietale, which is situated immediately at the base of the sagittal crest, or higher up than in any of the species here described. The mcahis auditorius externus is con- tracted, owing to the more than usual appi-oximatiou of the posttympanic and postglenoid processes. Dentition. — The bases of the crowns of the superior incisors are so robugt and the external so cylindric, as to render it very probable that their form is conic, as in the P. plati/copis The superior canine is large, and has a lentic- ular section at the base of nearly equal acumination of front and rear. The posterior edge is denticulate. (See specimen No. 2.) The second (first) premolar is quite small, and is situated two-thirds way from the canine to the third premolar. Its root is grooved on the inner side, but I cannot say whether it is double. The third premolar is large, and is separated from the canine by a space five-sixths the diameter of the latter. There are no other teeth in the specimen. Measurements of Ro. 1. m. Elevation from diastema to frontomaslUary suture 0G9 Width from orbit to premaxillary nareal border 036 Length of bases of three incisors 010 NIMEAVIDiE. 989 M. Diameters Of base Of canine l*"*""?"***"*"" *|lf ( transverse Oil Length from canine to third premolar 016 Oblique elevation of sagittal cusp above meatus of ear (partly estimated) 066 The maxillary bone of the second specimen contains all the molars, the third and fourth somewhat mutilated. The second is plainly two-rooted, and is half way between the canine and the third, which teeth are separated by a space equal to the length of the base of the anterior lobe of the latter. This tooth has no anterior basal lobe, but the posterior heel is rather elevated, though short. The sectorial is large ; its cusps are lost. The tubercular molar is small, and is esjjecially remarkable for its small transverse extent, which is about equal to that of the Nimravus gomphodus, and less than half that of the Pogonodon platycopis. It has nevertheless three roots, the median of which is posterior. The external end of the crown is visible from the side, behind the sectorial. Parts of both canines are preserved. A fragment from the front of the crown shows that the anterior cuttinof ed^e becomes lateral, and is denticulate. The anterior face has a shallow groove next the cutting edge. Enamel slightly roughened. The foramen infraorhitale is higher than wide in this species, and its ex- ternal border is above the anterior border of the antei'ior root of the sectorial, the supenor border of tlie molar being horizontal. The masseteric surface of the molar is vertical, not horizontal. The remaining parts of this specimen are two dorsal and three lumbar vertebrae, portions of both femora ; a patella ; proximal end of tibia ; both calcanea ; the cuboid and navicular bones, and first metatarsal. The verte- brae are well preserved ; see Plate LXXIV, figs. H-5. To compare with these I have at hand the corresponding parts of Uncia leo, U. concolor and U. pardus^ Cynonluriis jubatus and Fells domestica. The dorsal vertebrae are shorter and a little wider than those of U. concolor and U. pardus; also flat- ter below, and more distinctly medially keeled. Their proportions are more asjn the lion, where they are, however, regularly convex and not keeled. The anterior three lumbars are, on the other hand, of the pro- portions seen in U. concolor ^ U. pardus, and G. juhatus ; that is, relatively longfer than in the lion and shorter than in the common cat. Their centra are medially keeled below, but not so strongly as in the three species 990 THE JOHIJf DAT FAUNA. first named ; while the lateral tuberosities are more pronounced than in any of the species excepting U. X)ardiis and F. domestica, where they are stronger. In U. concoJor an U. leo they are weak, and in C. juhatus wanting. As iu these cats, they are below the line of the base of the diapophysis. The anapophyses are large on the last two dorsals and the first lumbar; on the second and third lumbar they are small, apparently shorter than in the Felidce above mentioned excepting Cyn. jubatus, where they are smaller still. The posterior borders of the neural spines of the lumbars are nearly straight from their origin behind and above the postzygapophyses, and their sum- mits are not much expanded. There is no trough-like excavation between the postzygapophyses above, as is seen in the panther, and in a less degree in the leopard and lion. The centra are not so much depressed as in the panther, leopard, and cat, or even as the lion, where they are the least depressed. The femora are a good deal injured, and the heads and trochanters are gone. It is evident, however, that they were of the same general propor- tions as those of the Nimravus goni])Jiodus^ and not very different from those of the panther. The external linea asper is acute, and the rotular groove high and rather narrow. The fossa between the insertions of the crucial ligaments between the condyles is deeper than in recent cats. The head of the tibia is also injured. (See fig. 6.) The internal posterior surface for the attachment of the cruciform ligament is large. The patella is a little nar- rower and more convex within than that of the panther. The bones of the foot preserved show clearly that, as in the case of the Arcliadurus dehilis, the extremities are relatively smaller than in recent Felidce of similar gen- eral size. While the portions of the skull of the Pogonodon hracliyops indi- cate an animal of rather larger size than the Uncia concolor, the bones of the hind foot are considerably smaller. The calcaneum is about three- fourths as long; the navicular is narrower though nearly as deep antero- posteriorly; the diameters of the cuboid are all less excepting the inferior facet anteroposteriorly ; the first metatarsal is more slender, and its proximal facet is little over half as wide. One character of the calcaneum which I do not find in any of my skeletons of Felidce or Hycenidce, is the presence of a longitudinal fossa for the insertion of the external lateral ligament, NIMEAVID^. 991 just below the external astragaline facet. The external border at the cuboid extremity of the calcaneum is even more prominent and recurved than in the existing cats, and the groove for the internal calcaneocuboid ligament is profound. The groove of the cuboid for the tendon of the peroneiis longiis muscle is deep, and commences at the anterior face of the bone, that is, anterior to its position in Uncia concolor and pardus and Cyncelurus juhatus, but its bounding ridge is not carried so far distally as in the panther. The small calcaneal face of the navicular is distinct from the astragaline surface. The character of the internal (free) surface of the head of the second (first) metatarsal shows that there was no hallux (first metatarsal). Measurements of Ifo. 2. M. Length of superior dental series from canine tootli 064 Length from canine to Pin. iii 015 Length of b.ise of Pm. iii .019 Elevation of crown of Pm. iii 013 Length of base of sectorial 024 Width of base of tubercular 008 Long diameter of base of canine 017 anteroposterior 028 vertical 017 transverse .026 ( anteroposterior 039 Diameters of centrum of third lumbar? ^^^gj-ioi. S vertical 020 ' < transverse 026 Elevation of last dorsal with spine 055 Elev.ition of third lumbar with spine 064 f anteroposterior 019 Diameters of middle of shaft of temur i ^^jjjngygi.ge .0-^5 Transverse diameter of head of tibia 047 Length of calcaneum 066 Width calcaneum at sustentaculum 027 I longitudinal 010 Diameters of navicular bone ^ . .(transverse 016 ^ ( fore-and-aft 005 ( longitudinal .017 Diameters cuboid 2 .(transverse 019 . J proximaK ^ ( fore-aud-aft 012 Although I do not possess a mandible of this species, I am satisfied that it is more nearly allied to Dinictis and the present genus than to Nim- ravus. It differs from the species of that genus and Archcelnriis in the fol- lowing points : (1) the truncate triangular posttympanic proxiess ; (2) the transverse frontomaxillary suture; (3) the preorbital impressed depression; (4) the superior position of the postparietal foramen. I anteropost Diameters of centrum of penultimate dorsaU anterior J 992 THE JOHN DAY FAUNA. Restoration. — This was a most formidable animal, and its dental char- acters indicate a high degree of efficiency of both the lacerative and of the biting fnnctions. While the P. platycopis has a larger development of the canine teeth, it is inferior in the relative size of the sectorials. In the latter respect the P. hrachyops resembles the species of Nimravus and ArchceluruSf but these are furnished with smaller or more slender canines. It, however^ resembled the latter in having the feet relativelj'" smaller than in the recent cats, a character which indicates inferior prehensile power. Unfortunately^ no ungual phalanges have been preserved, so that we cannot learn whether they confirm this indication by resembling those of the Cynceluriis jv.batus or the still less specialized forms of other families. History. — This species was the first of the Oregon felines of which bones were obtained. It was first sent here by Mr. C. H. Sternberg, from the Miocene bad lands of the John Day Valley, Oregon. HOPLOPHONEUS Cope. Annual Report U. S. Geol. Survey Territories, F. V. Haydeu, 1873 (1874), p. 509. Proceedings Acad- emy Philadolphia, 1879, p. 170. q 1 5 *> 1 Dental formula : I.-; C. -; Pm. — -; M. -. Inferior border of man- 3 1 2 1 dible flared downwards in front for the protection of the large double-edged superior canine tooth. Lateral and anterior faces of ramus sharply distin- guished. Incisors Avith wedge-shaped or conic crowns. Superior sec- toi'ial without anterior basal lobe ; inferior sectorial with a heel. No infe- rio)' tubercular molar. The original diagnosis of this genus includes the ascription of a tuber- cular molar to the inferior dental series, which is an error due to the refer- ence of a specimen to the H. oreodontis which does not belong to it. In this genus we reach the dental formula of Drepanodon and the true cats, while at the same time the primitive form of the sectorials of the lower jaw remains. I have not been able to examine the skull of a Drepanodon (Machcerodus), but from the silence of European authors it may be pre- sumed that the foramina which characterize the Nimravidce are absent, as- in the true cats. The fact that the species have been derived from the NIMEAVID^. 993 Pliocene and Upper Miocene formations increases the probability of the correctness of this supposition. I have ascertained that the American Plio- cene saber-tooths of the genus Smilodon possess the characters of the Felidce rather than those of the Nimravidce. Four or five species only of Roplophoneus are known as yet, all from North America. We may expect, however, to find the genus in various parts of the world, wherever the beds occur which represent the time im- mediately preceding the epoch of the true saber-tooths. The longest known species is the HoplopJioneus primceviis Leidy, from the White River bad lands of Dakota and Nebraska. It is about as large as the Canada lynx, and has long and slender superior canines. A larger species, the E. occidentalis Leidy, from the same horizon and locality, is known from two jaw frag- ments as large as the corresponding parts of the Nimravus gomphodus. Al- though the oldest members of the Nimravidce yet known from North Amer- ica, the Brepanodon characters of the mandible and of the superior canine tooth are well developed, much more so than in the false saber-tooth group of the later John Day epoch. In Europe, however, it must be remembered that the latter division commences still earlier; i. e., in the Upper Eocene, in the genus ^lurogale Filhol. As I have not obtained any parts of the H. primcevus and H. occidentalis not already described by Leidy, I confine myself at present to a descrip- tion of the H. oreodontis and H. cerebralis. HOPLOPHONEUS OREODONTIS CopC. Annual Keport F. V. Haydeu, U. S. Geol. Survey Terrs., 1872 (1873), p. 509. Machcerodxis oreodontis, Synopsis of New Vertebrata Colorado, Misc. Pub. U. S. G. S. Terrs., 1873, p. 9. Plate LXVII a, fig. 17 ; LXXV o, figs. 1, 2. •This saber-tooth was described from the fragment of a mandibular ramus supporting the temporary dentition. Subsequently I obtained at the same locality a large part of the skull, with portions of some of the limb bones of a fully grown specimen. The permanent dentition is in place, and is but little worn, while the epiphyses are not yet attached to the long bones. This specimen enables me to give a much fuller account of the species than heretofore. 63 C 994 THE WHITE EIVEE FAUNA. The profile is convex. The face is flat in front of the orbit, but is strongly convex for the alveolus of the superior canine in front of the infra- orbital foramen. The premaxillary border is moderately produced, and the palate is generally flat. The anterior border of the posterior nares is concave on each side of the median suture, which terminates at the apex of a projecting angle. The sagittal crest is not much elevated anteriorly, but rises steeply to the inion. The lateral occipital crests are prominent and nearly parallel. The occiput is not narrowed, and it is divided by a keel on the median line. There are no lateral keels or fossae. The suprameatal crest is thin, and the postglenoid process is not much extended transversely. The mandibular ramus is shallow, and of nearly equal depth below the molar teeth. The inferior flare is quite prominent, and the alveolar margin rises to the inferior canine. The symphysis is very deep, and the front of the chin is strongly convex at its superior part, and less so below, having a form quite different from that seen in the species of FelidcB already described, where it is flat and transverse. The symphyseal suture is longer above than below, and' the two parts are separated by a deep sinus without con- tact, which almost reaches the external surface. The angle of the ramus is not as much produced as in the species above described, and it is widened horizontally inwards. The masseteric fossa is profound, and its inferior and supero- anterior borders are prominent. There is a peculiar rough, flat tuberosity on the inner side of the superior border of the ramus, opposite the posterior part of the sectorial, which I do not find in the existing cats nor in the species of Nimravus, and of which a trace is seen in the Dinictis Cyclops. Sutures. — The frontomaxillary is almost vertical from the orbit, and turns downwards to join the lateral nasal suture for a very short distance oilly. It is there widely separated from the premaxillo-maxillary. The lachrymal bone is pear-shaped, with the narrow end directed downwards and back- wards, and joining the orbital plate of the palatine by a short suture. Its bounding sutures are not dentate. The anterior part of the orbitosphenoid is separated from the lachrymal by about the length of the inferior border of the latter bone. The palatal plate of the palatine bone extends as far forwards as the anterior border of the superior sectorials, and is broadly NIMEAVID^. 995 truncate anteriorly. The frontoparietal suture crosses the apex of the frontal space. Foramina. — The infraorbital foramen is large and subtriangular. Its posterior border is directly above the middle of the anterior root of the superior sectorial. The lachrymal is small. There are two nasoorbitals perforating the orbital plate of the palatine, of which the superior is the larger. The incisive foramina are large, and the palatals are small and opposite the anterior border of the (first) third premolar. The postparietal is well below the sagittal crest. The postglenoid is small. The dental foramen is large, and its center is below the middle line of the ramus, and below the anterior border of the base of the coronoid process. There are three external mental foramina on both rami; one below the front of the fourth premolar, one anterior to the front of the third premolar, and a larger one below the middle of the surface to which the superior canine tooth is applied. There are two anterior mental foramina which mark about the thirds of the depth of the chin. Dentition. — The width of the premaxillary region gives space for a full development of the incisors, which have robust bases. The canines, like the incisors, are broken off. Their bases show them to have been of large size, and of more compressed form than those of any of the species already described; Their long diameter considerably exceeds the length of the diastema which separates them from the third (first) premolar. There is no indication of the existence of a second premolar. As the outlines of the maxillary bones diverge strongly, the base of the third premolar is oblique. Its crown is broken off, but it was evidently not as large a tooth as in the species of Nifnravidce above described. Its base is one-half the length of that of the sectorial. The sectorial has its pi'incipal cusp prominent and acute, while its heel is low, but compressed and sharp. There is a rudiment of an anterior basal lobe, as is figured by Leidy in the H. primoevus. This tooth is characterized also by the very small size of its internal heel, which is continued downwards as a perfectly straight ridge, without interruption, to near the apex of the principal cusp. The edges of the tooth are little worn, and they show at several ^^oints anterior and posterior to the principal cusp a beautiful denticulate structure. The tubercular molar is large, but not 996 THE WHITE EIVER FAUNA. equal to that of Pogonodon platycopis or JDinidis cyclops. It has but two roots, and its crown is partly concealed from the side view by the posterior extremity of the sectorial. The mandibular incisors are well developed, and the canine is not much larger than the external incisor. Of the molars, the first is very small, though two-rooted, and has anterior and posterior basal lobes, although the former is minute. The fourth preraojar is intermediate in size between the third and the sectorial, and has anterior and posterior basal lobes, the posterior being the longer. The main cusp is not high, and its acute edges are crenulate. The sectorial has its principal cusp elevated ; the heel is short, and the internal tubercle stands on the posterior edge of the main cusp two-fifths the distance from the base of the crown. The enamel of the external sides of the last two molars is slightly wrinkled. Measurements. M. Axial Ifugth from premaxillary edge to orbit 041 Axial length from premaxillary edge to extremity of maxillary bone 061 Axial length to middle of posterior border of palate 060 Width of palate behind sectorials 054 Length from premaxillary border to frontoparietal suture on profile 095 Width of occiput at superior part 030 Length of base of third premolar 009 Length of base of sectorial 020 Width of base of tubercular molar Oil Length of mandible to augle 101 Length of dental series from I. i 067 Length of canine and incisor series (oblique) -^IS Length of diastema 019 Length of base of Pm. iii 006 Length of base of Pm. iv 012 Length of base of sectorial - 018 Depth of chin at symphysis 031 Depth of chin at flauge - 032 Depth of ramus at M. i 017 The mandibular ramus of the young animal already mentioned sup- ports the temporary sectorial, and displays two of the permanent incisors inclosed in the jaw in an unworn condition (Plate LXVIIa, fig. 17). The latter have slightly recurved conic crowns, with denticulate cutting edges. The sectorial has the character of that of most Felidce; there is a short acute heel, and an elevated compressed internal tubercle, which is as high as the anterior lobe of the crown. Its position is behind and a little within the median cusp of the tooth. NIMEAVIDiE. 997 Bemarks. — This species is nearly allied to the Hoplophoneus lorimcevus, •of which it may be only a regional variety. It is distinguished by its shorter and wider face and palate, a character especially seen in the short- ness of the diastema, which is considerably less than in the Nebraska spe- cies. With this animal it compares much as th^ bull-dog does with the ordinary varieties of the genus Cams. The two specimens I have described were found by myself on a denuded portion of the White River formation in Northeastern Colorado. At the same locality were multitudes of bones, mostly jaws, of fifty species of various orders of Mammalia and Reptilia, on many of wliich it doubtless preyed. HOPLOPHONEUS CEREBRALIS Cope. American Naturalist, 1880, Dec, p. 850. Machwrodus cerebralis Cope, American Naturalist, 1880, p. 143 (January 31). Plate LXXVa; figs. 3, 4, 5. Probably the smallest species of the genus, and one that presents peculiar characters. This peculiar species, the smallest of the genus, approaches nearest in dentition to the true saber-tooths {Drepanodoii), and is represented by a skull, from wliich the basioccipital region, a good deal of the right side, and the lower jaw, are absent. It differs in many respects from all the members of this family of cats heretofore discovered in North America. In almost every point in the osteol- ogy of the skull it is peculiar. There is not as much space for the temporal muscle as in most of the extinct species described, or as in the large recent Uncice, but the points of origin of the muscle indicate that it was rela- tively stronger than in the domestic cat and the lynxes. Its single pre- molar is very small, so that tlie dentition for practical use is reduced, in the upper jaw, to the canine and sectorial. Both have been most effective instruments in the performance of their respective functions. The sectorial has a distinct anterior basal lobe. The space for the accommodation of the brain is relatively more ample than in any other feline of the formation, -and the inner wall indicates that the convolutions of the hemispheres were well developed. This species, if the cranium were of usual proportions, "was about the size of the red lynx {Lynx ritfus). 998 THE JOHN DAY TAUKA. The facies is quite different from that of the species heretofore de- scribed, the profile more nearly resembling that of some of the smaller species which belong to the genus Felts. It is much less convex than usual, for though the nasal bones descend, the sagittal crest is horizontal and the occiput vertical, when the sphenoid bone is held in a horizontal position. The side of the face is slightly concave in front of the orbit, and plane in front of the infraorbital foramen as far as the gentle curva- ture to the nareal border. There is a low protuberance on each frontal bone, near the maxillary suture, a little nearer the median suture than the super- ciliary border. From it the surface descends rapidly to the superciliary border. The postorbital process is longer and more recurved than in any of the species of the White River period, resembling more nearly that of the recent Felidce. The orbit has less vertical and more lateral presentation than in many of the species, owing to the less prominence of the anterior part of the zygoma It is of a vertically oval form, owing largely to the shortness of its superciliary border. The parts of the zygoma remaining are slender, and the malar portion turns inwards below. The sagittal crest is long, but is quite narrow and low. The brain-case is relatively large, and the parietal surface of the temporal fossa is regularly convex. The occiput is quite wide, and does not project backwai'ds as in the larger and many of the smaller cats The lateral crests are not prominent, and are quite obsolete above the mastoid region. The posterior face is impressed by a number of small fossfe and foramina. Though the occiput is some- what imperfect, there is evidence that there was no paroccipital process; even less than the rudiment found in most of the recent Felidce. Above its position, forming the external expansion of the exoccipital bone, is a low tuberosity. The posttympanic process is quite long, and is subcylindric and truncate. It does not touch the postglenoid. The lateral occipital crest is continued as a delicate ridge which divides it lengthwise externally. It does not give off the suprameatal crest, which is low, but expands into the thin posterior superior edge of the squamosal part of the zygoma. The latter is more expanded posteriorly than anteriorly. The anterior part of the basioccipital has a median groove, which is continued on the basi- sphenoid. The pterygoid processes of the palatine bone have rounded infe- NIMEAVLDiEJ. 999 rior edges. The nareal border of the palatines consists of two pronounced concavities separated by a prominent point. The border of each concavity supports two contiguous obtuse tubercles well separated from each other. The external one of these is separated from the acute deflected posterior border of the maxillary bone by a concavity of the horizontal surface. The posterior front of the palate is slightly concave on each side of the median line, and presents a deep excavation on the inner side of the sectorial, to receive the crown of a large inferior sectorial. This fossa has a straight inner border. The palate is concave between the canines; behind them on each side, a shallow groove enters the palatine foramen. The characters of the palate described are quite peculiar among cats. Sutures. — The premaxillomaxillary suture joins the nasal suture well above the nareal border of the nasal bones, but does not probably meet the frontomaxillary. The latter is arched upwards to a point above the anterior third of the orbit. Its nasal terminus is lost from both sides. The fronto- parietal suture crosses the sagittal crest well behind the junction of the temporal ridges. The parietosphenoid suture is quite long. The squamo- sal bone is not much longer than it is deep to the meatus auditorius. The maxillo-palatine suture extends along the inner border of the fossa for the inferior sectorial. Foramina. — The external nares are rather small, partly curving to the prolongation of the nasal bones. The infraorbital foramen is round and small for a cat; owing to the lack of prominence of the malar bone it has a partially external opening. The lachrymal is normal and well inside the orbit. The optic is close to the sphenoorbital and is of usual size. The sphenoorbital and round foramina are united into a single large anteriorly directed opening; whether the internal perforations are united or not, the state of the specimen does not allow me to see. There is an alisphenoid canal, which connects the external opening with a common foramen with the / ovale. Its diameter is small. The / ovale is large, and is not widely separated from the meatus auditorius internus. The / postglenoideum is mod- erate, and terminates in a groove in the anterior wall of the meatus audito- rius. The basioccipital bone being absent, the relations of various foramina cannot be ascertained. There are two postparietals, both penetrating the 1000 THE JOHN DAY FAUNA. inferior part of the bone, the posterior near the lateral occipital crest. The palatine foramen is rather large. It is much nearer the alveolar border than to the median sutm-e, and is opposite the anterior border of the third premolar tooth. Dentition. — The bases of two incisors, and both canines, are preserved with the crowns of the molars of one side. The base of the external inci- sor is not so much larger than that of the second, as in the cats already described. It is separated from the canine by a diastema half as long as that posterior to the canine. The latter is two-thirds as long as the long diameter of the canine. The base of the canine is of a compressed oval form, with a slight concavity on the inner side. It is much like that of the Hoplophonem oreodontis, but is relatively larger. In fact, it is relatively larger than in any other American saber-tooth, excepting the Pogonodon platycopis. There are but three molars. The first or third premolar is quite small, but has, as usual, two roots. The crown has a low compressed anterior basal tubercle, and a small median cusp. The heel is rather long, equaling the long diameter of the base of the cusp, and is compressed. The sectorial is relatively large. It is somewhat worn by use, but its form is character- istic. Its cutting heel is very long, while the base of the principal cusp is small. There is a distinct anterior basal cutting lobe, as in the true Drepan- odontes. The external face of the crown is concave before and behind the median cusp. The tubercular or true molar has been lost; there are alveoli for two roots, rather close together. The position of the external alveolus shows that the crown extended externally to the plane of the jaw. Measurements. H. Length from iiremaxillary border to iuion 117 Probable width of zygomata posteriorly 082 Axial length from premaxillary border to orbit 040 Axial length from premaxillary border to nares 057 Axial length from i)remasillary border to postglenoid process 0i!5 Width between superior canines , 020 Width between sectorials behind 043 Width of posterior nares 012 Width of occiput above middle 037 Width between orbits (horizontally) 047 Length of sagittal crest 038 Length of postglenoid from roof of meatus 018 Length of posttympanic (total) Oil NIMRAVID^. 1001 M. Length of glenoid cavity (transversely) - 017 Vertical diameter of orbit 025 Length of base of canine 016 Width of base of canine 017 Length of diastema Oil Lengthof molar teeth on base 025 Length of Pni. iii 006 Length of sectorial 017 The unique specimen of this species was found by Mr. J. L. Wortman in the bad lands of Camp Creek, one of the head tributaries of the Crooked River, in Central Oregon. • HOPLOPHONEUS STRIGIDENS Cope. American Naturalist, 1880, December, p. 851. Machwrodus strigidens Cope, Paleontological Bulletin, No. 30, p. 9 (Dec. 3, 1878). Proceed. Amer. Philos. Soc, 1878, p. 71. Plate LXXVo; fig. 6. This obviously distinct species is only represented by the crown of a superior canine tooth, from which the apex has been broken. Its charac- ters are so peculiar that I have recorded it under the above name, not knowing whether I shall have better specimens. The tooth is long and very much compressed, much more so than in any species of the genus known to me. Its anterior and posterior edges are finely and very perfectly denticulate, without lateral flexure near the base. The center of each side of the tooth is occupied by a wide open gutter, so that the greatest transverse diameter of the crown is not at its middle. These gutters become planes towards the apex, giving an elon- gated hexagonal section. The size indicates an animal of the proportions of the H. cerebralis. As compared with the superior canine of the Dinidis squalidens, which the present specimen resembles in its compression and fine denticulation, it differs in its greater relative length and in the presence of the lateral open sulci. ^leasurements. M. anteroposterior 0120 ' — S s:S""::-.::::::::::::::::::::::::::::::::::::::::::::;: :S Diameters at base Length of a denticle on base 000143 1002 THE JOHX DAY FAUNA. Bemarhs. — This tooth belonged to an animal of about the size of the H. cerebralis, and perhaps to that species. If so, it indicates foi' it a longer canine than usual, as its extremely compressed form points to a position at a considerable distance beyond the base of the crown. The probabilities are against reference to the D. cerebralis. The tooth is the most elegant in form and perfect in its details yet found. As a cutting instrument it is superior to anything of human manu- facture which I have seen. Found by C. H. Sternberg, on the John Day River, Oregon, in the Truckee beds. (The White River and John l)ay Faunae are continued in Vol. IV.) IIS^DEX. Page. Aceratherinin ••«• •• •• 34, 38, 691 Achffinodon 36,259,343 insolens 343 Aciprion 776 formosnm 776 .ailarogale 38 Adapia 36,216 Adapidfe 240 Addenda to Part First 727 Adocidfe HI Adocas 1^3 iElnridse 89" Agomphas - •• '■^3 Amblyctonidae 259 Amblyctonus 260 Amblypoda 167,379,507 Amia 745 dictyocephala 745 scntata 745 Amphitragnlns 38 Amphiccelias 26 Amphicyon 38, 39, 894 cnspigems 898 hartshomianns 896 Tetns 894 Amphiemys 113 Amphimery x — 36 Amphiplaga 83 brachyptera 84 Araynodon •• 33 Amyzon 748 commnno . — 749 fusiforme 751 mentale 749 pandatum 750 AnacodoQ - 386, 427 nrsidens '♦27 Anaptomorphidae 240 Anaptomorphns 36,216,240,245 Eemnlus 248 homnocnllia 249 Anchilopbns 713 Anchippus 713 Ancbippodus ^^5 Anchitherinm 34,38,714 Ancylotberium 34,39 Anisonchas 386, 408 conifems - ^^^ gilliaciu *11 sectoriua ^13 AnoplotheriidsB ■ 34 Anoplotherinm 36 Page. Anoatira 112, 127 omata 128 radnlina 128 Anthracotberium 34,36 Apbeliscus 216 Aphelopa 39,691 Aphelophia 781 talpivoms 782 Apbododirids 80 Apbolidemya 113 AquitaniaD 34 ArcbsElurus 38, 952 debilia 953 Arctocyonidffl 259 Arctocyon 29,259 Arctictidaj 892 Aitiodactyla 379,716 Asineopa 84 panciradiatns 87 sqaamifroDS 85 Atelodns 692 Anblysodon 30 Avea 754 Aseataa 112,116 byasmos 116 Baena 112,144 arenosa 148 bebraVca 146 ponderosa 150 nndata 147 Baenid* 33,111 Bathmodon 517,544 pachypaa 549 radians 544 Bathyopsis 561,596 fissidens 697 Batrachia 100 Blastomeryx 39 BunEelums 946 lagophogua 946 osomm 947 Bndger 33,36 Bimotheria 167,185,800 Csenobasilena 39 Cgenopua 691 Caenofberium 34,39 Calamagias 764 mnrirorns 784 Calamodon 188 1003 1004 INDEX. Page. Cnlamodon cyliodrifer 192 simplex 189 Camarasaoms 26 beds 26