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18 84. 


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indorsement of Jul}* 20th, relating to the unpublished reports of the sur- 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, 



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. 




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1 lie yet unpublished volumes will be pushed to completion at an 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. 




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. 


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 

4. The restoration of Hyracotherium, the four-toed horse of the Wasatcli 

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- 


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, 

United States Geological Survey of the Territories. 
The Hon. the Secretary of the I^TERIOR, 

Washington, D. C. 






Book I. 





1883 . 



Letter of transmission xx 

Proftice xxiii 


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 


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 




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 


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' 


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 


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- 


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 4<KV 

zniiienBia 401 

Diaco<lL-xiH 4<)2 

Diaiodcxi.s latiriincns 402 

.Mriiisi'dtbiTiiiin 4y;5 

Mcuincotlifrinin ttTiicnibra) 4<J,). 

tapiacitJH ."lOCi 

Aiiiblypoda 507 

I'antiidoiila ,'14 

.Mautcoduii 517 

Maiiti <Mlon KiibipiadratiiH 518- 

r.rtacddnn 51!) 

l^i-IaciMbiii riiiiHii* ,",20' 


Thb P0ERCO, Wasatch, and Bridger Faunae — Continued. 

Mammalia : Pag& 

Coryphodon 521 

Coryphodon cnspidat ng 525 

latipes 526 

elephantopns 53X 

simns 532 

repandus 532 

curvioristis ,533 

marginatns 535 

anax ■ 537 

Bathmodon 544 

Bathmodon radians 544 

pachypus ,549 

Metalophodon 554 

Metalopliodon annatus 555 

testis 557 

Dinocerata 559 

Eobasileus 561 

Eobasileus pressicomis 502 

furcatus 565 

Loxolophodon 569 

Loxolophodon cornntus 574 

galeatus 5^5 

Uintatherium 587 

Uinta therium robustiim 589 

lacustre 591 

sp 5!13 

Bathyopsis 596 

Bathy opsis fissidens 597 

Taligrada 600 

Pantolambda 601 

Pantolambda bathmodon 603 

Diplarthra 613 

Perissodactyla 614 

Lophiodontid^ 617 

Systemodon 618 

Systemodon tapirinus 619 

semihiaus 622 

Hyracotherinm 624 

Hyracotherinm craspedotum 631 

vassacciense 634 

Yenticolum 635 

osbornianum 647 

angustidens 648 

index 650 

Pliolophu8 650 

Pliolophus cinctus 652 

Heptodon 653 

Heptodon posticus 654 

ventorum 654 

calciculus 656 

Hyrachyus R>7 

Hyrachyus princeps 661 

sp 661 

eximius 662 



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 



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 


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 


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 


The White River and John Day Faun^— Continued. 


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 


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. 


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 


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 

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. 


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 


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 


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. 


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. 


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 





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 


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. 


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 

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 (; 


(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 Anaptomorphid<B of the Prosimiae. 
(11.) The reconstruction oi Hyracotherium; and 
(12.) OiHyrachyus. 

(13.) The discovery of numerous Marsupialia in the Lower Miocene. 
(14.) The discovery of the phylogenetic series of the Canidae; and 
(15.) The same of the ancestors of the Felidae. 


Page 167. For Diplcethra read Diplarthra. 

Page IfiB. In table of genera, correct definition of genus Polymastodon to read: Fourth Inferior pre- 
molar conical, simple ; inferior molars with two, superior molars with three, rows of tubercles. Strike 
•out genus Catopsalis and its definition, as they refer to the inferior dentition of Polymastodon. 

Page 169. In phylogenetic table of Plagiaulacidse erase Catopsalis, and place Polymastodon on a side 
branch out of the line between Thylacoleo and Ctenacodon; one which is derived from such mesozoic 
forms as Tritylodon and Stereognathus of Owen. 

Page 240. The genus Necroleinur is erroneously included iu the Anaptomorphidse and should be 
placed in the family Mixodectidte. The arrangement of the genera of these families is then as follows 
^see American Naturalist, 1884, p. 60) : 

I. Canine teeth large and latesal ; well separated. 
First superior premolar without internal lobe ; superior true molars tritubercular with cingula. . Tricenie*. 
II. Canine teeth median in position or much reduced in size. 
a. Last inferior premolar without internal tubercle. 

nferior premolars all one-rooted. Canine and incisor small Neerolemur. 

First premolar only one-rooted; canine small; incisor very large Mixodeetes. 

aci. Last inferior premolar with internal tubercle. 

A very large ? canine; first premolar only one-rooted Microsyops. 

A very large f canine; first and second premolars both one-rooted Cynodontomya. 

The new genus Tricentes includes three species, and perhaps four. It will be described in the last 
part of Volume IV of this series with the genus Indrodon of the next family. 
The genera of Auaptomorphidae diifer as follows : 
a. Incisors three. 
First superior premolar without inner lobe; posterior inner tubercle present on first and second snperioi 

true molars Indrodon. 

aa. Incisors two. 
First superior premolar with inner lobe ; no posterior inner tubercle on superior molars. ..inoptomorpAu*. 

Page 260. Line 7, the genus Diacodon should probably be removed to the section of the family where 
the fourth premolar is different in character from the first true molar. 

Page 391. In synonymy of Periptvchus rhabdodon, for Catathtcerhus read Calalhlceua. 

Page 739. Omit from the definition of the Prosimiie, in the table at the bottom of the page, the words 
" superior true molars quadritubercalar." 

Page 920. Eighth line from bottom, for "fishes" read fisher. 

Explanation of Plate XXIX d (p. 42), at bottom, correct fig. 2 by stating that the anterior two teeth 
figured belong really to the lower jaw, which is very robust, and that the second upper premolar has 
an internal lobe. Add that the Periptychua dilrigonut does not belong to Conoryctes, but to a genus of 
PeriptychidsB, which differs from all those known by the presence of a conic cusp external to the usual 
external tubercles of the superior molars. It may be called Ectoconns m. To an allied genos must be 
referred the second specimen figured and described as Conoryctea comma m. 





The principal Tertiary formations of the region between the Mississippi 
River and the Sieira Nevada are the following, as mainly determined by Dr. 
Hayden : The Puerco, the Wasatch, the Bridger, the Uinta, the White River, 
the Loup Fork, and the Equus beds. Several of these are again distinctly 
subdivided, and in a few instances such divisions have been regarded by 
authors as of equal importance with those above mentioned; as, for instance, 
the Green River portion of the Wasatch. But the evidence of vertebrate 
paleontology is not as yet clearly favorable to further primary subdivision 
than is indicated by the above names. I will briefly describe the character 
and distribution of these formations before entering on the description of 
the fossils which they contain. 

The general history of the succession of the Tertiary Lakes of the 
interior of the North American continent and their deposits has been devel- 
oped by the labors of various geologists, prominent among whom must be 
mentioned Hayden, Newberry, and King. It may be synoptically stated 
as follows : 

The Laramie-Cretaceous period witnessed a great difference in the 
topography of the opposite sides of the Rocky Mountain range. To the 
east were extensive bodies of brackish and nearly fresh water, with Umited 
ocean communication, studded with islands and bordered by forests. On 


the west side of the range was a broad continent, composed of mostly- 
marine Mesozoic rocks, whose boundaries are not yet well ascertained. 
Towards the close of the Laramie the bed of the grreat eastern sea begran to 
emerge from the watere, and the continent of the western side of the great 
range descended. The relations of the two regions were changed ; the 
east became the continent and the west became the sea. The latter, receiv- 
ing the drainage of the surrounding lands, was a body of fresh water, whose 
connection with the ocean permitted the entrance of a few marine fishes 
only. This was the great AVasatch Lake, whose deposits extend from the 
headwaters of the Yellowstone far south into New Mexico and Arizona, 
between the Eocky Mountains on the east and the Wasatch range on the 
west. Its absence from the east side of the former range indicates the con- 
tinental condition of that area at the time. The only locality where the 
Wasatch deposits ai-e extensively deposited on the Laramie, is in the region 
intermediate between the two di.stiicts in Wyoming and New Mexico. Here 
the sediments of the former are seen to have succeeded those of the latter, 
and to have been coincident with an entire cessation of brackish conditions. 
Elevations of the continent northward and southward conti'acted the area 
of the gi-eat Wasatch sea, and perhaps deepened it, for at this time were 
deposited the fine limestones and silico-calcareous shales of the Green River 
epoch. There is no evidence that these beds had a greater eastern exten- 
sion than that of the parent Wasatch Lake. King has given distinct 
names to these ancient lakes. I think it better to pursue the usual course 
of using for them the names already given to their deposits, as involving 
less strain on the memor}- ; the more as the number of these lakes will be 
probably enlarged by future discoveries. The only known region covered 
by this lake west of the Wasatch range, is represented to-day by the 
calcareous strata in Central Utah, which I have called the Manti beds. The 
exact equivalency of these is, however, not quite certain. Fiu-ther con- 
traction reduced this area to perhaps two lake basins, whose deposits now 
form two isolated tracts in Southern Wyoming, and are known as the 
Bridger formation. Continued elevation and di-ainage caused the desicca- 
tion of these basins also, leaving only, so far as present knowledge extends, 
a body of water on the south of the Uinta Mountains, in Northeastern 


Utah. The sediments of this lake form the Uinta formation, which is the 
latest member of the series now found in the region lying between the 
Rocky and Wasatch Mountains. 

About the time that the elevation of the present drainage basin of the 
Colorado River was completed, a general subsidence of level of the great 
region east of the Rocky Mountains commenced. Extensive lakes were 
formed in the depressions of the Laramie and older beds which formed the 
surface, which were probably connected over a tract extending from near 
the Missouri River to Eastern Wyoming and Colorado. At the same time 
a similar body of fresh water occupied a large part of what is now Centi-al 
Oregon and certain areas in Northwestern Nevada, according to King. 
The sediments now deposited constitute the White River formation, and the 
faunal distinctions which I have discovered to characterize the eastern and 
western basins have led me to employ for them the subdivisional names of 
White River beds for the former and Truckee (King) for the latter. It 
may have been during the early part of this period, or during the Uinta, 
that there existed two contemporary bodies of water, separated by a wide 
interval of territory. One of these extended over a considerable tract in 
Northern Nevada, and deposited a coal bed near Osino. A formation prob- 
ably the same has been found by Professor Condon in Central Oregon 
underlying the Truckee Miocene beds. The other lake left its sediments 
near Florissant, in the South Park of Colorado. This formation I have 
named the Amyzon beds,* from a characteristic genus of fishes which 
is found in it. It has been referred to the Green River formation by 
King, but without the necessary paleontological evidence, as it appears 
to me. 

The oscillations of the surface which brought the White River period 
to a close are not well understood. Suffice it to say here, that after an 
interval of time another series of lakes was formed, Avhich have left their 
deposits at intervals over a wider extent of the continent than have those 
of any other epoch. These constitute the beds of the Loup Fork period, 
which are found at many points between the SieiTa Nevada and the Rocky 
Mountains from Oregon to New Mexico, and over parts of the Great Plains 

* American Naturalist, May, 1879. 


of Colorado, Kansas, and northward, and in the valleys of the Rocky- 
Mountains. A probably continuous succession of lakes has existed from 

this period to the present time in ever-dimin- 
ishing numbers. The most important of these 
were in the Great Basin in Oregon, in Wash- 
ington, and in Nebraska, and their deposits 
enclose the remains of a fauna entirely dis- 
tinct from that of the Loup Fork period and 
of more modern character. They are known 
as the Equus beds. This fauna was proba- 
bly contemporaneous with that which roamed 
f" ^ through the forests of the eastern portion of 
B ^ the continent, whose remains are enclosed in 
the deposits of the caves excavated from the 
ancient limestones. 

A more detailed account of the forma- 
tions is now given. Faunal lists are reserved 
for the close of the volume. 

a ^■ 

o .S 
^ . 



^ '' 














3 o 
* H 

^ 2 


5 S 

^ :: 

This formation, having furnished nu- 
merous Mammalian fossils, is known to be- 
long to the Tertiary rather than the Post- 
Cretaceous series. It is regarded by Dr. 
lilndlich as a subdivision of the Wasatch, 
but the characteristics of its fauna are so 
marked as to constitute it a distinct horizon. 
The most southern locality at which it 
^. has been observed, the one from which I 
named it, and where its characters are dis- 
tinctly displayed, is west of the Jemez and 
si Nacimiento Mountains, in New Mexico, at the 
sources of the Puerco River. At this place its outcrop is about 500 feet in 


«. - 

£ t g 


'' Bta.iOi^i. 

Sm.i4 ^74. 


thickness, and has an extent of several miles on both sides of the river. 
From this point the strike is northwards, keep- 
ing at the distance of a few miles to the east- 
ward of an escarpment of Wasatch formation. 

It contracts in depth to the northward, and 3 

beyond the Gallinas Mountains I have not ob- •"* 

served it. I 


It is well developed in Southern Colorado, p 

where Dr. F. M. Endhch* and WiUiam H. Holmes,t I 

of Dr. Hayden's Survey, detected it in 1876. Its §" 

mineral character is there similar to that seen in | 


New Mexico, and its thickness is much greater. % 

On the Animas River it is 1,000 to 1,200 feet; ^ 

on the San Juan River, near the Great Hog ^ 

Back, 700 feet. The general characters of the 5 

. i 

formation are expressed in the following descrip- » 

tion, extracted from my report to Lieut. G. M. S 

Wheeler.J g 


South of the boundary of tbe Wasatch, the varied g- 

green and gray marls formed the material of the coun- "' 

try, forming bad-land tracts of considerable extent and % 

utter barrenness. They formed conical hills and flat o 

meadows, intersected by deep arroyos, whose i)eri>endic- 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. 




"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. 



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 


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. 


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. 



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* 



l Y ii i i ' i i' iyi l'i f T T 

T i ' i ,i'i i !M'i,i' i i: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- 


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). 


Ked-striped marls 1,500 

Eeddishbrown sandstone 1,000 

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 

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 


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. 


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. 


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 


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. 


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. 



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 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 



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. 












Gr.ay and grceuish-gr.iv sandstone, varying from 
a very fine compact structure to a conglomerate. 

Bijon HiUs, Medicine 
Hills, Eagle Kest Hills. 




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. 





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. 



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 



Yellow and light-yellow calcareous marl, with 
argillo-calcareous concretions and slabs of silicious 
limestone, containing well-preserved fresh-water 

On the south side of 
White River. Seen in its 
greatest thickncssatPinao's 



* Proceedings Academy Philada., 18.")", p. l-'iS. 
tReportof Geol. Survey of 40tli rarnllel, i, 410. 
JL. c, p. 423; 1. c., p. 415. 










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 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<ands. 


Light-gray calcareous grit, passing down into a 
stratum composed of an aggregate of rather coarse 
granular quartz, underlaid by an ash-colored argil- 
laceous indurated bed with a greenish tinge. Men- 
odus bed. 

Best developed at the en- 
trance of the basin from 
Bear Creek. Seen also in 
the channel of White River. 



The foUowinop diagi-am represents without much detail the section in 
Eastern Coloi-ado, along the Horse Tail Creek, from the Chalk Bluffs south- 
ward. (See fig. 6, p. 16.) 

At both localities the lower beds cany the bones of the gigantic Chali- 
cotJieriidce, Mevodus in Nebraska, and Symhorodon with Menodus in Colorado. 
But few other types occur in this bed in Colorado, the great number of 
genera and species being found in bed B, in which I did not discover' any 
fragments of ChalicotJieriidce among a large quantity of remains of Ungu- 
lata, Carnivora, Bodentia, etc. The lithology is as follows: Bed A is a 
white calcareous soft clay rock, breaking into angular fragments. Bed 
B has a similar mineral character, with frequently a red color of different 
obscure shades. Bed C is a sandstone of varying persistence. Bed D is 
a white argillaceous rock like that of bed A. Fossils are less numerous 
than in bed B, and included no Symhorodons nor other ClinlicotJieriidce. 

The eastern area of this formation is the true White River epoch of 
Hayden; the western deposits form the Truckee epoch of King. I named 



this formation the 

According to 

Oregon, but Mr. King's name is the older, and must be 

Professor Condon, the Truckee formation of Oregon, on 
the John Day River, rests unconformably on the 
laminated beds containing Toxodium and fish 
remains, which, as I have suggested on a pre- 
vious page, may be an extension of the Amyzon 
shales. These in turn rest on a formation of hard 
laminated beds, which contain an abundance of 
Calamites, which doubtless belong to the Triassic 
or Jurassic period. The Truckee beds are, like 
^ the true White River, overlaid by the Loup Fork, 
S, and this in turn by heavy beds of basalt. 

The fauna of the Tnickee presents some 
g characters which distinguish it from that of the 
o White River. These are, the absence of Hya- 
£ nodon and Ischyromys and most of the Menodon- 
J tidoe, and the presence of several genera of Canidce, 
■S FelidcE, and Bodentia. Many genera, and appar- 
ently several species, were common to the two 


This formation has now been studied in 
many widely-separated localities in the region 
west of the Mississippi River. It was discovered 
by Dr. Hayden, whose collections furnished the 
basis of Dr. Leidv's determination in 1858.+ It 
was next observed by myself in Colorado in 
18 73, J and twenty-one species wei*e determined ; 
and, in the following year, I identified the 
Santa F^ marls of New Mexico, already observed by Dr. Hayden, with the 

• Bnlletin U. 8. Geol. Sorv. Terra., v, p. 52. 

tSco Proc. Acad. Nat. 8ci. Phila., I^.V, p. 20, and Extinct Mammalia of Dakota and Nebraska. 

$ Bulletin of the U. S. Geol. Sorv. Torrg., No. 1, Jan., 1874. 


same horizon * Messrs Hayden and King have discovered it west of the 
Wasatch Range in Utah and Nevada, and Marsh has observed it in Oregon. 
Messrs. Dana and Grinnell found it occupying the valley of Deep River in 
Montana, and Professor Mudge and myself have seen it in Northern and 
Western Kansas. There is a near lithological resemblance between the 
strata at these localities, and the fauna presents a common character as dis- 
tinguished from those which preceded and followed it; but sufficient care 
has not always been exercised to distinguish its upper members from the 
Equus beds above them. The latter contain a distinct fauna.f 

According to King, about 1,500 feet of beds are included in this 
formation. Hayden found 300 to 400 feet on the Loup Fork and Niobrara 
Rivers. The following is his section, beginning at the top: 

It consists of, "1st. Drab-gray or brown sand, loose, incoherent, with 
remains of mastodon, elephant, etc. 2d. Sand and gravel, incoherent. 
3d. Yellowish-white grit, with many calcareous arenaceous concretions. 
4th Gray sand with a greenish tinge ; contains the greater part of the or- 
ganic remains. 5th. Deep yellowish-red arenaceous marl. 6th. Yellowish- 
gray grit, sometimes quite calcareous, with numerous layers of concretion- 
ary limestone from 2 to 6 inches in thickness, containing fresh-water and 
land shells, Succinea, Limnfea, Paludina, Helix, etc., closely allied and per- 
haps identical with living species ; also much wood of a coniferous charac- 
ter." The White River section appears at the upper part of the table, on 
page 14. 

The water-shed between the South Platte River and the Lodge Pole 
Creek is composed superficially of formations of the Loup Fork epoch, as 
defined by Hayden. On its southern side is an abrupt descent in the level 
of the country, which generally presents the character of a line of bluffs 
varying from 200 to 900 feet in height. This line bends to the eastward, 
and extends in a nearly east and west direction for at least sixty miles. 

The upper portion of this line of blufi's and buttes is composed of the 
Loup Fork sandstone in alternating strata of harder and softer consistency. 
It is usually of medium hardness, and such beds, where exposed, on both 

•Ann. Eep. Chief of Engineers, 1874, 11, p. 603. 

t See Bulletin U. S. Geol. Surv. Terrs, Iv, p. 389, and v, p. 47. 

2 c 


the Lodge Pole and South Platte slopes of the water-shed, appear to be 
penetrated by numerous tortuous friable silicious rods and stem-like bodies 
They resemble the roots of the vegetation of a swamp, and such they may 
have been, as the stratum is frequently filled with remains of animals which 
have been buried while it was in a soft state. No better-preserved remains 
of plants were seen. The depth of the eiitire formation is not more than 
75 feet, of which the softer beds are the lower, and vary in depth from one 
foot to twenty. The superior strata are either sandstone, conglomerate, or a 
coarse sand of varying thickness and alternating relations ; the conglom- 
erate contains white pebbles and rolled Loup Fork mammalian remains. 

This formation rests on a stratum of white friable argillaceous rock of 
the White River epoch, as represented in Fig. 6. 

The lithological characters above described are precisely those pre- 
sented b3' the same formation in New Mexico.* 

Mr. King employs the name Niobrara for this formation, but Dr. 
Hayden's namef was introduced many years previously. The new name 
has also the disadvantage of being already in use for a horizon of the Cre- 
taceous, which is well distinguished paleontologically. 

I have divided the Loup River formation into two divisions, on pale- 
ontological gi'Ounds,J under the names of the Ticholeptus bed and the 
Procamelns bed. The former occur in the valley of Deep River, Montana, on 
the White River in Northern Nebraska, and in Western Nebraska, Avhere 
it has been found by Mr. Hill. Its fauna presents in Montana a mixture of 
fossils of the Procamelus horizon ; while in Nebraska, according to Hayden, 
its typical genera are accompanied by White River mammalia. In the 
former region, IlippotUerium, Protohippus, and Blastomeryx are mingled with 
genera allied to Leptauchenia and with Merycochcerus. In Nebraska, Leptau- 
chenia is said to be accompanied by Ischyromys, Palceolagus, Hyracodon, and 
even Oreodon, genera which do not extend to the Procamelus bed. There 
is, however, a question in my mind whether this collocation is entirely cor- 
rect It is bed D of Hayden's section in Leidy's Extinct Fauna, Dakota and 
Nebra.ska, p. 20. 

• So« l;i-|><>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. 


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. 


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. 



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 

Fig. tki. — Sinid Hills Noitliwe.steru Ni braska i'rom Hayden. 

sectio:n" II. 


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. 


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 

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. 


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 


than it is at the other Hmit of its existence, viz, the period of its disappear- 

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. 


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- 


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- 

American. Kiiroiiciin. 

Camarasaurus Beds. "Wealden. 

f Iguanodon. 

f Ilypsilophodon. Hypsilophodon. 

t Cettosaurus. Cetiosaurus. 

Camarasaurus. Ornithopsis* 


fGoniopholis. GoniopJwlis. 

'CJumdrotttotaurut Owen. 


American. European. 


HypsirJiophus. Omosaurus. 

Caulodon. f Caulodon.* 


Epanterias. Streptospondylus. 


" 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. 


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 


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. 


a. Teetiaey. 





Clastes. Clastes. 



y?. Peculiar. 




Sables de Bracheux and Con- 




y. Ceetaceous. 








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 


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 

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- 


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 


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. 


The above table exhibits the present state of our knowledge ; it will 
doubtless be much extended by future discovery, but not otherwise 

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 


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. 


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. 


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. 


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. 









Necrohmur (Phosph). 


f Didelphys. 





Adapis. f Ui.Tr«iwU>j 






Hyrachyus (Phosph.). Hyrachyu-s. 

Tapirulus. Tapirulus. 

Anfhracotherium. Achcenodon. 






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, 


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 

Stampian and Aquitanian. White River. 
Didelphys. Didelphys. 

ProtomyidcB Protomyid(B.\\ 


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. 




Stampian and Aquitanian. 

Adurogale (Phosp.). 







Leptomeryx (Phosph.). 

White River. 












Hyopotamidce . 


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. 



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. 











Hippotherium (Oeningian). 


Loup Fork. 





• CanU ursinua Cope. 

t PUoMppus Marsh. 


Falunian. Loup Fork. 

Cosorijx. Cosoryx. 


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 : 


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. 



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). 
Hydrochcsnis (p). 

Lagomys (s). 
Lepus (s). 

Arctotherium (p). 
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. 


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. 


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- 

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 


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 

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. 


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. 



vey of the Ten-itories for 1872, pp. 410-417. It will be observed that there 
is a constant discrepancy between the two tables. 




Loup Fork . 


White River 


Upper 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 ... 


Lower limits not positively fixed; largely developed in Italy, t (Subapennine, E.D.C.) 

Ocningian; Mayencian; Aquitanian. 


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. 


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. 






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. 



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 49 


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. 


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 


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 



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. 


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. 



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 


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. 



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. 



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. 


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. 



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 


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. 



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, 


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. 


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. 



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. 



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<bra 038 

Length of cent mm of vertebra 009 

From the bluffs of Cottonwood Creek. 


Pappichthys plicatus Cope. 

Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 635. 
Plate III, figs. 13-19, and Plate IV, figs. 1-5. 

Established on a series of bones of the skull and vertebrae. Some of 
the cranial bones are deeply grooved and with parallel ridges between. 
The outer face of the dentary is roughly grooved on the inferior half of its 
posterior two-thirds. The inner face is marked by a strong groove near its 
middle to the symphysis, above which it is very convex; below it extends 
to a thin edge. The dental alveoli are shallow and in close contact ; there 
are six in .025 m. at its middle, where it is also .019 deep. The teeth become 
smaller at the symphysis. The maxillary bone is rod-like proximally, but 
flattens out much distally, and is there slightly rugose in parallel lines on 
the outer face. The teeth are smaller than the mandibulars, there' being at 
the middle fourteen in .025 m. The alveoli are larger proximally. The 
depth of the bone at the beginning of the suture for the supplementary 
maxillary is .020 m. The superior extremity of the hyomandibular is 
broad and flat. The inferior quadrate is thickened behind, and has a 
broadly oval condyle. The coarsely serrate suture of the pterygoid adjoins 
it closely. Number cranial ridges in .010 m., ten. The vertebrae preserved 
are from an anterior position and are quite short and have sessile diapophy- 
ses; they are broader than deep; width, m., .026; depth, .019; thickness, 
.005. The articular surfaces for the neural arches are confluent, so as to 
have a subquadrate outline. 

Another specimen is represented by numerous fragments, one of which 
is the right maxillary bone. The proximal extremity of this element rises 
beak-like upward, and shows on its inferior surface the face for contact with 
the premaxillary. A portion of this bone passed behind the tooth-bearing 
part of the maxillary for a short distance, and in front of the proximal end 
of the beak. The external face of the maxillary is nearly flat, and is 
delicately grooved distally only ; the inner face is strongly convex. The 
teeth are close together, and gradually increase in size, and become more 
cylindric at the base to the anterior extremity. The crowns are lost. 

A fragment of supposed palatine bone exhibits a series of large margi- 


nal teeth, and numerous smaller ones Nvithin them, as in Amia calva. Its 
superior face exhibits a deep, longitudinal groove, which opens out poste- 
riorh-. The prootic bone is a half disk, thickened on the straight edge and 
with concave sides with a round, flat tuberosity on one of them. On some 
of the cranial bones the ridges are interrupted. 

Six adjacent abdominal vertebra? of this individual are less transveree 
than the corresponding ones of the P. medius (Leidy) and the anterior ones 
found with the specimen of P. lilicatus above described. The diapophyses 
occupy nearly the middle of the sides of the centrum, and are rather 
elongate. The outline of the articular faces above the level of these 
processes is a regular wide arch ; below them it consists of three sides, 
two long laterals which are nearly straight, and a short median inferior one, 
which is slightly concave. The apices of the articular cavities are above 
the middle. The inferior surface is marked by two parallel angles, each of 
which bears a naiTow longitudinal imdivided fossa, which are separated by 
a concavity. The neurapophysial facets are nearly divided by a median 
constriction, and are of unequal size. 

Pappichthys corsoni Cope. 

Anuual Report U. S. Geol. Surv. Terrs., 1872, p. G3C. P. tymphtisis Cope, 1. c, 636. 

Plato IV, figs. 21-36. 

Established on a number of vertebrae of an individual which was of 
much smaller zize than any of the preceding, and about equal to the largest 
gi-owth of A. calva. The fomi of the dorsal centra is a little wider than 
deep ; the caudal deeper than wide. What distinguishes these from the 
vertebrae of the species above described is the lack of distinction between 
the articular facets of the adjacent neurapophyses. These are almost 
confluent instead of nearly or quite isolated, as in the P. Icevis and P.plicatus. 



Length of centrnra dorsal 006 

Depth iif ciMitnini dorsal 014 

Wiilth c.f (■.ntriiiii dorsal 018 

Depth of I'l'iitriiiu raudul 0115 

Width of cunt rum caudal 0105 

Length of centruiu caudal 0040 


The dorsals of the above specimen have short diapophyses, and might 
be regarded as posterior, and the anterior might be anticipated to present a 
different type of articulation with the neurapophyses, as in P. plicatus. But 
a vertebra of the same size and form but with long diapophyses, from 
another locality (Upper Green River), presents the same subquadrate 
articular faces, slightly constricted in the middle. Hence I suspect this 
character to be characteristic of the species. 

Another specimen is rather smaller than the last. A dorsal vertebra, 
with inferior diapophyses, is but little wider than deep. The articular 
surfaces for the neurapophyses are 8-shaped, the areas confluent. A 
marked peculiarity is seen in the dentary bone. It is much curved in the 
vertical plane as well as in the horizontal, and must have inclosed a wide 
mouth. The groove is median, and the inferior and superior surfaces reach 
it by a nearly equal slope. The former leaves the alveoli without horizontal 
border, though the latter themselves open on a horizontal plane. There are 
four and a fraction in .010 m. 



Depth of ramus at middlo 013 

Thickness of ramus at middle 006 

Length of posterior dorsal vertebra 006 

Depth of posterior dorsal vertebra 012 

Width of iiosterior dorsal vertebra 013 

From Upper Green River, dedicated to Dr. Joseph Corson, formerly 
at Fort Bridger, Wyoming, whose researches among the vertebrata of the 
Bridger basin were attended by rich results. 


Gill; Cope, Proceedings American Association for the Advancement of Science, 1871, p. 330. 

Parietal and supraoccipital bones confluent. Four anterior vertebrae 
coossified, and with ossicula auditus. No mesopterygium. Basis cranii and 
pterotic simple; no coronoid bone. Third superior pharyngeal bone want- 
ing, or small and resting on the fourth; second directed backwards. One 
or two pairs of basal branchihyals; two pairs of branchihyals. Suboper- 
culum wanting; premaxillary forming mouth border above. Interclavicles 


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. 


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 



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. 




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- 

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 




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. 


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. 



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 


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. 



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. 



Length of Hpinc on riin'c 052 

Dianii'tcr at liane; long 006 

Diameter at banc ; iihort 004 


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. 


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 


in the caudal fin. (Psuedobranchite and pyloric appendages). Clupeid<B. 
Tail, homocercal; pterotic, normal; basis cranii, simple; basal branchihyals 
and superior pharyngeals, each three ; (no pseudobranchige) Osteoglossida. 
To the first named family belongs the genus Diplomystus; to the last 
named, Dapedoglossiis. 


Bulletin U. S. Geol. Snrv. Terra., 1877, p. 807 (Augost 15). Phareodua (nomen nudum) Lcidy. Proceed. 
Acad. Nat. Sci. Phila., 1873, p. 99. Fiual Report U. S. Geol. Snrv. Terra., i, p. 193. 

A single row of elongate acute teeth on the premaxillary, maxillary, 
and dentary bones, vomer, tongue, and (?) basihyal bones closely studded 
with short conic grinding teeth. Mouth rather short. Pectoral fin with 
the anterior ray elongated ; dorsal fin not elongate, with the anal well 
separated from the caudal. No beards. Two vertebrae included witliin the 
caudal fin. 

This interesting genus presents the characters of the family to which I 
refer it, in its segmented scales, posterior dorsal fin, etc., and does not differ 
widely in essentials from Osteoglossum. The principal differences between 
the two genera are, the small mouth in Bapedoglossus, the absence of 
barbels, and the generally abreviated form. From Arapama, it differs in 
proportions, and in the abundance of teeth on the bones of the roof and 
floor of the mouth. 

The peculiar structure of the scales characteristic of this family is well 
displayed in this genus. The whole of the scale is composed, between the 
inferior and superior surface layers, of subhexagonal or diamond-shaped 
cells, which are arranged in spirals trending to the center. Their contents 
are more thoroughly calcified on the exposed than in the concealed portion 
of the scale. No radial grooves. Tube of the lateral line issuing by a 
round pore. 

The discovery of this genus, in the Green River shales, is one of the 
most interesting in the history of this department of paleontology which 
has been made. 

Osteoglossum is known only in a recent state, and with a range of dis- 
b'ibutlon quite unparalleled among Teleostean fishes. Thus one species — 
0. bicirrhosum, Vand., occurs in Brazil; 0. fonnosum, Schl. Miill., in Bor- 


neo, etc., and 0. leichardtii Gthr., in New Zealand, all in the southern hemis- 
phere, or near the equator. Two other genera, Vastres and Heterotis, have 
been associated with it, and these belong to the same hemisphere, or to those 
faunae which characterize it, in their extensions north of the equator. It is, 
therefore, interesting to note that the first representative of the type found 
in any of the northern faunal regions, belongs to an age evidently Eocene. 

Our first knowledge of this family and genus as it occurs in North 
America, was based on a fragment of shale from the railroad cut at Green 
River, Wyoming, which bears part of the scales of one side of the body 
of the fish. The specimen is without any portion of the head or fins. In 
consideration of the structure of the scales I was induced to refer the 
species to the genus Osteoglossum. The next addition to our knowledge of 
this form was furnished by Dr. Leidy, who gave a brief description of 
portions of the jaws supporting teeth, of a species found in the Bridget 
foi-mation. This fish he termed Pliareodus acutus. No diagnosis of the 
genus was given, nor were any grounds for creating it assigned. I have 
not, therefore, been able to use the name. Subsequently I attempted to 
•define the genus thus named by Dr. Leidy,* inadvertently writing it Phare- 
cdon. The specimens of jaws then in my possession were found by myself, 
mingled with the bones of Rhineastes, and it was from the latter that my 
diagnosis was drawn up. Phareodon Cope must then be regarded as a 
synonym of Rhineastes, and as it had its origin in error, naturalists will 
probably agree with me in sinking it altogether. 

Four species of this genus are enumerated in the following pages, but 
I am not able to give the distinguishing characters of three of them. It is 
probable that the D. acutus Leidy is distinct from the other two, which have 
been found in the Green River shales, but as only its jaws are known, 
these offer but few characters. At present the type specimen of D. encaustus 
remains considerably larger than any of those of the D. testis, which have 
been found, and comes from a locality distant from whei'e the latter is found. 

• Annual Report U. S.Geol. Surv. Terrs.,1872 (1873), p. 637. 


Dapedoglossus encaustus Cope. 

Balletin U. 8. Gcol. Surv. Terrs., 1677, p. 808. Osteoglo$»um enoauitum Cope, Annnal Report U. 8. GeoL 

8nrv. Terrs., 1870, p. 430. 

Plate VI, fig. 1. 

Eepresented by a portion of the side of a large individual, including 
the series of scales bearing the lateral lines, and three series above and 
three below it, more or less perfectly preserved. The longitudinal extent 
of the fragment includes seventeen transverse series. These scales are of 
large size, the included portions are smooth to the naked eye, but rugose 
under the microscope, and with but few and faint traces of concentric lines. 
Exposed portion with entire margin, bearing a large lenticular rugose sur- 
face. This rugosity consists of elevated portions of an enamel-like mate- 
rial, between small pits and gi-ooves. The septa between the cells are dis- 
tinctly visible on the smooth part of the scale; on the rugose surface they 
are represented by grooves. The cells are in curved series, which extend 
to the center of growth, growing smaller as they converge. The rugose part 
of the exposed surface diminishes in relative extent towards the anterior part 
of the body. The tubes of the lateral line are in this species concealed 
beneath the extenial layer of the scale. The opening is nearer the margin 
than the center of the scale, is round, and is frequently accompanied by a 
smaller one above and in front of it. 



Length of fifteen consecntive scales 23 

Depth of six longitudinal scries scales 127 

Vertical diaraeter of a scale 0^ 

Transverse diameter of a scale C25 

Diameter of a submarginal scale cell 001} 

Width of rugose nreii of scale Oil 

As compared with the species of Osteoghsswm, whose scales have been 
figured, the present oflfers clear distinction. In 0. hicirrhosum, figured in 
Agassiz and Spix Brazilian Fishes, Tab. XXV, the scales have distinct con- 
centric grooves, and the rugosity consists of a few points or projections. 
In 0. formosum, figured in Solomon Mueller's travels in Borneo, &c., the 
rugosity is uniform on the exjioscd surface, and very minute, and there are 


no concentric grooves ; the cells are smaller. In Vastres the exposed sur- 
faces are still more rugose; in large examples quite honeycombed. 

The specimens represent an individual of 3 or 4 feet in length. Dis- 
covered at the fish slate cut on the Green River, on the line of the Union 
Pacific Railroad by Lucius E. Ricksecker, C. E. 

Dapedoglossus testis Cope. 

Bulletin U. S. Geol. Snrv. Terrs., 1877, p. 807 (August 15). 
Plate VII, fig. 1 ; Plate VIII, figs. 1-2. 

Form oval, contracting subequally to the muzzle and caudal peduncle. 
The fi-ont is gently convex and the mouth is terminal. The depth is little 
less than half the length minus the caudal fin, and the length of the head 
enters the same 3.4 times. The dorsal fin is shorter than the anal, and its 
first ray stands over the sixth of the latter. The ventrals are small, and 
extend about one-half the distance from their base to the first anal ray, which 
equals the distance to the base of the pectoral. The latter is elongate, 
especially the first ray, which, although jointed, as in Osteoglossum bicir- 
rhosum, reaches nearly to the end of the ventral. Radii: D. 22-23; A. 27— 
30. The caudal fin is slightly concave. Scales five or six series above the 
vertebral column and seven below it. Their exposed surface is rather wide, 
and is minutely granulated and without grooves. The cells are invisible 
except when this sm-face is removed, and they are rather large. Vertebrse, 
18 dorsal, 24-25 caudal. 

The orbit is rather large, and is reached by the end of the maxillary 
bone. The suborbital bones are not much enlarged, as is the case in the 
recent genera. Preoperculum entire ; suboperculum very naiTow. Branchi- 
ostegals slender, rather numerous ; coracoid wide, forming a vertical keel, 
which is not produced. Length of the longest specimen, 0™.230; of the 
shortest, O^.IBS. 

The numerous specimens of this which I have seen differ in size, and 
are three-fifths and less, of the dimensions of the JD. encaustus. 

As compared with the D. acutus, I notice that the dentary bone does 
not support quite so many long teeth. I count twenty-three in the former 
and seventeen or eighteen in the I), testis. 

From the Green River shales at Twin Creek, Wyoming, 


Dapedoglossus acdtus Leidy. 

Phareodui acutui Leidy, Proceed. Acad., Phila., 1873, p. 99; Final Report U. 8. GeoL Surv. Terra., i, 

p. 193, Plate 32, figs. 47-51. 
Pkareodon acutiu Leidy, Cope, part. Annual Report U. 8. Geol. Surv. Terrs., 1872 (1873), p. 637. 
Phareodon tericeut Cope, 1. c, p. 63!^. 

Plate V, figs. 18-20. 

Represented by numerous remains. The teeth, as preserved, are black 
with white ti-anslucent slightly incui-ved apices The dentary bones are 
deep, incurved, and with an erect elevated point at the symphysis; their 
outer surface is rugose with deep longitudinal grooves and pits of irregular 
sizes. They are narrow transversely, and support a single series of twenty 
two or three closely placed slender teeth, which together form a comb. 
The bases of these teeth are nigose-striate, and the apices abruptly acumi- 



Depth of dentary at symphysis 009 

Depth of dentary at fourteenth tooth 015 

Length of eighth tooth 0056 

Diameter of eighth tooth at base 0015 

Six teeth in 0100 

The palatine bones support a mass of teeth, there being one external 
series of large ones rather abruptly pointed, and several series of small 
ones of little elevation, whose size diminishes inwards. On two teeth of 
the external series of a large individual, I proposed the species Phareodon 
sericeus, with the following description : "They differ from those of the 
P. acutus in their large size and stout conic form ; also in having the basal 
Btriation finer, parallel, and extending over half the length of the crown. 
The basal portions as preserved are black, the apex white, and with a 
slightly abrupt contraction." 


No. L 

No. 2. 

No. 3. 

Length of crown 




Damoter of crown at base ... ................ .-.-.. 

The specimens of Dapedoglossus acutus which I have seen, I obtained 
from the upper valley of Green River, from the marls of the Bridger epoch. 


Dapedoglossus iEQUiPiNNis Cope. 

Bulletin U. S. Geol. Surv. Terrs., 1878, p. 77 (February 5). 
Plate VU, fig. 2. 

Two specimens present the principal character of this species, viz, the 
equality in number of rays in the dorsal and anal fins and the near equality 
in their size. The radii are in one, D. 23 ; A. 22 : in the other, D. 22 ; 
A. 22. In B. testis, the formula is D. II — 18 ; A. 11—26. The vertebrae 
in one of the specimens of D. aquipinnis number D. 19; C. 27 : while in 
D. testis there are, D. 18 ; C. 24-25. (The number, 21 dorsal, originally 
given, must be corrected, as based on an imperfect specimen.) In D. (equi- 
pinnis, the first pectoral ray is not so largely developed as in X). testis, not 
being of unusual size The hyoid apparatus and vomer are closely studded 
with teeth, as required by the generic character. 


Length of No. 1 051 

Axial length of head of No. 1 014 

Axial length to line of anal fin 030 

Axial length to Hue of dorsal .028 

Axial length to origin of caudal 040 

Depth of head 012 

Depth at first dorsal ray 008 

Depth of caudal peduncle 004 

Length of No. 2 092 

Depth at middle of dorsal line 032 

Depth at base of dorsal fin 024 

Depth of caudal peduncle 008 

The specimens described are much smaller than those of the D. testis 
yet known, and No. 1 is probably young. This fact will not account for 
the peculiarity of the radial formula, etc. 

Green River shales at Twin Creek, Wyoming. 


BuUetin U. S. Geol. Surv. Terrs., 1877, p. 808 (August 15). 

Family Clupieida;, and nearly related to the genus Clupea. It differs 
from Clupea in the presence of a series of dorsal scuta, which extend from 
the supraoccipital region to the base of the dorsal fin, con-esponding in 
position with those of the ventral surface. Unlike these, they have no 


lateral processes. The dorsal fin originates in front of the anal. In the 
typical forms, teeth are well developed in a single series on the dentary, 
premaxillary, and maxillary bones ; but, in the small forms, they are 
invisiljle. ilouth moderate. 

There are two sections of this genus, the species of which differ in the 
fomi of the dorsal scuta. In section I, these shields are transverse, and 
their posterior borders are pectinate, a median tooth being especially prom- 
inent. In section II, the scuta are not wider than long, and have but one, 
a median tooth, which is the extremity of a median longitudinal carina. 
The species of section I are D. dentatus, D. analis, D. theta, and D. pectorosxis ; 
those of section II are D. humilis and D. altus. The species of section I 
display a longer anal fin than those of section II. 

The species of this genus were more numerous in individuals than all 
others combined, during the period of the Green River Lake. 


Bulletin U. S. Geol. Snrv. Terra., 1877, p. 809. 

Plate X, fig. 1. 

Fin-radii: D.I — 13; A. I. 35. Vertebi'ee : dorsal, 18; caudal, 21. 
The greatest depth enters the length without the caudal fin two and a half 
times, and the head enters the same nearly three and one-third times. The 
eye is large, its horizontal diameter a little exceeding the length from its 
border to the inferior edge of the premaxillary bone, and is a little greater 
than one-fourth the length of the head. - The premaxillary and dentary 
bones are short and deep, the latter with a deep notch on the anterior border; 
both are directed upwards. The maxillary bone is long and narrow, and 
curved backwards at its lower end, which reaches a point below the anterior 
border of the orbit. The profile behind the premaxillary bone is nearly 
horizontal ; above the posterior part of the orbit, it rises, and a compressed 
supraoccipitivl crest carries it to the gently convex dorsal line. The abdo- 
men is convex, and is about as long as the caudal region. The last dorsal 
ray rises above a point anterior to the first anal ray. The caudal is deeply 
forked. The ventrals originate at a point barely in advance of a vertical 
line from the first dorsal ray. The pectoral fins are short. The scuta of 


the inferior median line are large and acute. The scales are rather small, 
and are delicately grooved ; twenty rows may be counted between the 
vertebral column and the dorsal fin. 


Total length 365 

Length of head 083 

Length (axial) to below first dorsal ray 145 

Length to above first anal ray . 185 

Length to base of external caudal rays 285 

Depth at orbit 055 

Depth at occiput 093 

Depth at first dorsal ray 118 

Depth at middle anal ray 050 

Depth at base of caudal fin 030 

Not rare at Twin Creek ; specimens occur of fifty centimeters length, 
or about the size of the shad. 


Bulletin U. S. Geol. Surv. Terrs., 1877, p. 809. 
Plate VII, fig. 4; Pl.ate VUI, fig. 3; Plate X, fig. 2. 

Radial formula: D. I. 11; A. I. 40. Vertebrae: dorsal, 17-18; caudal, 
23-24. This species is more elongate in proportion to its depth than either 
of the other species, the length being three times the greatest depth. The 
anal portion of the body is considerably longer than the abdomen, and the 
anal fin is long and with short rays. The ventral fin commences well in 
front of the dorsal, whose last ray is considerably in advance of the first 
anal ray. The pectoral fin reaches the ventral, and contains thirteen rays. 
The greatest depth is at the pectoral region, the outlines contracting to the 
base of the anal fin. The dorsal outline is convex. The profile descends 
gently. The muzzle is half as long as the diameter of the orbit, which 
enters the length of the head three times. The latter enters the length 
without the caudal fin three and three-fourths times There is a row of 
short, conical teeth along the middle line of the mouth, which is not on the 
vomer, but is on the parasphenoid or axial hyal bones. Similar teeth exist 
in the mouth of I), dentatus. The jaws may be furnished with minute teeth, 
or they may be wanting. The scales are thin and difficult to count ; there 
are fifteen rows between the vertebral column and the anterior anal rays. 




Total length I'JS 

Length of head 040 

Axial length to below first dorsal ray 073 

Axial length to above first anal ray 092 

Axial length to baae of external caudal rays 149 

Depth at orbit 030 

Depth at occiput 044 

Depth at first dorsal ray 047 

Dei>th 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. 


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. 




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 


This species is represented by several specimens, from Twin Creek 


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. 


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 


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. ' 



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 


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. 


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. 


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. 




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 


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. 



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 


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. 



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 


the anal is below the penultimate dorsal ray. The caudal fin is openly 




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. 


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 

But one species of this genus is yet known. 


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. ^ 


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. 


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 


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— 


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. 



Total Iciigtii of tho largest specimen 19 

Do. No. 2, smaller example (with caudal) l~ 

Length of hcail of do 014 

Depth of <ln. posteriorly alioiit 0156 

length of hasc of spinous dorsal OSCu 

Length of jjostcrior spinous ray 017 

Length of opercnliim 0125 

Length of ninxillnry bono nbont 0M5 

Depth No. 3, nt liase 1st dorsal 045 

Depth No. :t, at base annl, InI ray 0325 

Length of basis anal^bosis caudal 0162 

Iicngth of caudal fin , 034 


Tertiary strata of Green River, Wyoming; Dr. F. V. Hay den, Coll. 
Mus. Smithsonian. 

In the original specimen of this species, but nine soft anal rays were 
preserved; in a more perfect one, subsequently obtained, I find eleven or 
twelve. I characterized a supposed species under the name of A. viridensis 
on small specimens, one of which was stated to possess fourteen soft anal 
rays. A re-examination of this fish leads me to believe that the separate 
rods which represent this number are parts of but twelve rays. 

I have not seen the Asineops squamifrons from the Twin Creek locality, 
where another species takes its place. 


BnUetin U. S. Geol. Snrv. Terrs., 1877, p. 813. 
PI. XIV, fig. 1. 

This Perch is represented by a single specimen, which is larger than any 
of those of the A. squamifrons, which have yet been found, and which is of more 
robust proportions. It differs materially in the radial and vertebral formulae, 
and in the greater relative shortness of the dorsal spines. I observe at 
the base of these, a series of short subhorizontal basilar interneural bones. 

Foi-mulEe:— Radii: D.IX-12; A. II. 7. Vertebrae: D. 9; C. 13. One 
or two vertebrae may be concealed behind the epiclavicle, but these, as in 
the description of A. squamifrons, are uncounted. The depth enters the 
length 2.25 times, the caudal fin being omitted. The length of the head is 
little less than the depth. The dorsal spines are not very robust, and are 
(excepting the first) of subequal length. The longest equals only half the 
depth of the body at the middle of the second dorsal fin. The caudal is 
rounded, and the ventrals are below the pectorals. The origin of the latter 
is a little in advance of that of the first dorsal spine. Its base is attached 
to four short basilar bones, of which the inferior two are stout in proportions 
There are about ten rows of cycloid scales below the vertebral column. 
Scales extend on the top of the head as far as the orbits. The mouth is termi- 
nal. The total length of the type-specimen is ".243, of which the head 
constitutes ".075. The longest (ninth) dorsal spine measures ".027, and 
the second anal spine ".024. 

Twin Creek, Wyoming. 



BnUetin U. S. GeoL Surv. Terra., 1877, p. 813. 

Allied to Labrax and Perca Branchiostegal rays, 7 or 8 ; ventral 
rays, I. 5 ; scales ctenoid. Two dorsal fins slightly connected at base ; 
only two anal spines. Operculum rounded, without spines or emargination. 
Preoperculum without spine, and smooth on the posterior border ; inferior 
border with teeth. Premaxillary and dentary with small uniform teeth in 
a narrow series. Clavicle unarmed. Vertebrae with two lateral fossae. 
Caudal fin emarginate. 

The discovery of this genus in the Green River shales is of no small 
importance to fossil ichthyology, proving the existence, at that early period, 
of the type which is one of the highest among the true fishes. It probably 
beloi:g8 to the Percid^B, although I have not ascertained the presence of 
teeth on the vomer, and there may be eight branchiostegal rays. As 
compared with the genera, recent and extinct, which are allied to Perca, it 
differs in the unarmed operculum, and the preoperculum with teeth only on 
the lower limb, and in the presence of but two anal spines It is therefore 
a weaker form than they, and though of a higher type, less strongly 
protected by spines than the cotemporary Asineops. Mioplosus embraces 
the largest Physoclystous fishes yet known from this formation, and speci- 
mens are not rare at the locality from which they have been procured. 
They are often in a state of excellent preservation. The type of the genus 
is the M. lahracoides. 

Bulletin U. S. G«ol. Surv. Terra., 1877, p. 814. 

The M. abbreviatus is represented by but one specimen, from which 
the muzzle has been broken away. It is the stout species of the genus, and 
the others succeed it in this enumeration in the order of their greater elon- 
gation of form. The depth at the first dorsal fin enters the total length 
(including caudal fin) three and a half times ; and the depth at the first 
anal ray enters the length of the vertebral column two and eight-tenths 
times. Vertebrae visible behind clavicle: D. 9 ; C. 14. Radii: D. IX — L 


11 ; A. II — 11 ; P. 14. Ventral with a very weak spine. The last dorsal 
spines, as in all the other species, are very short, the anterior ones slender 
and moderately long ; in this species they are curved. The anal spines are 
short and slender, the fii'st a rudiment. There are six rows of scales above 
and six below the vertebral column on the caudal peduncle. 



Length of vertebral column 125 

Length of third dorsal spine 025 

Length of ninth dorsal spine 007 

Depth at middle of first dorsal fia 060 

Depth of caudal peduncle 025 

Twin Creek, Wyoming. 


Bulletin U. S. Geol. Surv. Terrs., 1877, p. 814. 
Plate XII, fig. 1. 

This Perch is represented by five specimens, mostly in good preserva- 
tion. They have much the jDroportions of the Rock-fish. The origins of 
the pectoral and ventral are in nearly the same vertical line, and that of the 
first dorsal is not far behind them. That of the first ray of the anal is 
below the second or third ray of the second dorsal. The rays of none of 
the fins are prolonged ; the dorsal spines are slender and nearly straight; 
the longest (third), when depressed, reaches but four-tenths the distance to 
the first ray of the second dorsal. The last dorsal spine is very short. The 
soft dorsal rays are rather longer than the spinous. Formulae : — Rays : D. 
IX— I. 12; C. 8-17-8; A. 11—14; V. I. 5. Vertebrae: D. 10; C. 15. 

The depth at the first dorsal fin enters the total four times ; the depth 
at the first anal ray enters the length of the vertebral column three times. 
The length of the head enters the total four times, and that of the orbit 
enters the head 4 66 times, and into the length of the muzzle one and one- 
third times. The profile of the top of the head is slightly convex, and the 
dorsal line is also slightly convex. The mouth opens somewhat obliquely 
upward. The end of the maxillary bone reaches a point below the middle 
of the orbit. The teeth of the inferior border of the preoperculum are 
strong, and are directed forward ; they number five. The angle of the 


lower jaw is not produced, but the inferior edge of the ramus is laminar and 
acute ; the symphysis is shortly truncate. The superior edge of the maxil- 
lary bears a supernumerary bone at its distal portion. There are six 
branchiostegal rays preserved, with impressions of two others : the anterior 
three are slender ; the others wide, as in allied genera. There is a low 
supraoccipital crest. The abdomen bears fourteen rows of scales below the 
vertebral column, and six rows may be counted above it ; on the caudal 

peduncle I count 5 — 5. 



Total length 280 

Axial lengih of head 070 

Axinl length to lino of first dorsal spine 085 

Axial length to lino of first ray of second dorsal 143 

Axial length to lino of first anal spine 152 

Axial length to base of caudal 232 

Depth at orbit 051 

Depth at first anal ray 055 

Depth of caudal peduncle 030 

Length of third dorsal spine 030 

Length of second anal spine 016 

Abundant at Twin Creek, Wyoming. A single specimen from Green 
River, Wyoming, from L. E. Ricksecker. 

MioPLosus LONGUS Cope. 

Bulletin U. 8. Geol. Sur v. Terra. , 1877, p. 815. 
Plate XU, fig. 3. 

I have questioned the right of the form to which the above name is 
given to be maintained as a species distinct from the M. labracoides. It is 
represented by two individuals of much smaller size than those of the lat- 
ter, and which are of a more elongate form. They have also two anal radii 

The formulae are: D. IX— 12; A. II. 12. Vertebrje: D. 10; C. 15. 
The depth at the first dorsal fin enters the total length five times, and the 
depth at the first anal ray three and one-half to three and eight-tenths 
times. The dorsal spines are straight and slender, the posterior ones very 
short. The caudal is forked. The teeth of the inferior border of the pre- 
operculum are strong and acute; there are three large and two small ones. 


Measurements. m. 

Total length 175 

Length of head 042 

Length to line of first dorsal 054 

Length to line of second dorsal 085 

Length to line of anal 091 

Length to caudal 140 

Depth at orbit 025 

Depth at first dorsal 037 

Depth at second dorsal 034 

Depth of caudal peduncle .020 

The scales are similar to those of the Jf. Idbracoides. 
Twin Creek, Wyoming. 

MioPLOsus BEANi Cope. 

BuUetin U. S. Geol. Surv. Terrs., 1877, p. 816. 
Plate XU, fig. 2. 

This, the most slender species of the genus, is represented by one speci- 
men, which is the smallest obtained which is referable to this genus. The 
depth enters the total length six times, and the depth at the fii'st anal spine 
enters the length of the vertebral column a little more than four times. 
Radii: D. IX— I. 13; A. 11—12; P. 13. Vertebra: D. 10; C. 15. The 
general characters are as in M. Idbracoides, but the scales are not preserved 
The form of the head is that of a younger fish, but its proportions as com- 
pared with the body are not those of immaturity. The length enters the 
total 4.2 times, and the orbit enters it 4.5 times. The profile of the front is 
descending. The teeth of the inferior limb of the preopercle are obtuse 
and not well defined. There are impressions of seven branchiostegals pre- 

This Perch is named in honor of my friend Dr. T. H. Bean, of the 
United States Fish Commission. 

Measurements. m. 

Totallength 131 

Length of head 031 

Length to line of first dorsal 040 

Length to line of second dorsal 064 

Length to line of anal fin 070 

Length to line of caudal fin 109 

Depth at orbit 020 

Depth at first dorsal ray 023 

Depth at first anal ray 019 

Depth of caudal peduncle Oil 

From Twin Creek, Wyoming. 



This fish is known to me by a single specimen of the average size of 
the M. lahracoides. It is distinguished from that species by its more slender 
proportions, and especially by the elongation of its muzzle, which projects 
a little beyond the lower jaw. In M. lahracoides it is the inferior jaw 
which projects. M. sauvageanus also differs from all the known species of 
the genus in the small number of its soft anal rays, and larger number of 
its vertebra. 

Radial formula; D. VI +, 14; A. I, 9. Vertebrae, D. XI, C. XVI. 
Depth at middle of first dorsal fin (the greatest) enters the length to the 
extremity of the vertebral column, 3 5-G times, that is, nearly five times in 
the total length. In M. lahracoides this dimension enters the same length 
three times or a little over. The dentary bone is quite shallow, and the chin 
and inferior crests are less prominent than in M. lahracoides. The inferior 
preopercular teeth are distinct. 

From the Green River shales of Twin Creek, Wyoming, from Mr. 
Leroy, of the Central Pacific Railroad. 

Dedicated to my friend Dr. H. E. Sauvage, of Paris, author of various 
important works on ancient and modern fishes. 


Bulletin U. S. Geol. Surv. Terrs., 1877, p. 816. 

This type might be included in the Pomacentrida;, but it differs from 
the genera now known in the possession of vomerine teeth, and apparently 
in having eight branchiostegal rays. 

In general, Priscacara may be characterized as Pharyngognathi, with 
ctenoid scales and well-developed spinous rays. The preoperculum is, in the 
typical species, sharply seiTate on both free borders. There are three anal 
spines, and the lateral line is well developed, not extending near the dorsal 
line. The caudal fin is rounded. The jaws are toothless. The pharyngeal 
bones, both superior and inferior, are closely studded with short, sessile, 
conical, teeth; a row of small ones stands on the external border of the 
inferior pharyngeal. One dorsal fin. 

The species of Priscacara are referable to two sections. In the first, 


the ventral spine is very strong^, and there are but ten or eleven soft dorsal 
radii : here belong P. serrata, P. ci/pha, P. oxyprion, and P. testudinaria. In 
the second, the first ventral spine is weak and slender, and there ai*e thir- 
teen or fourteen radii of the second dorsal fin; in this division belong P. 
Hops, P. pealei, and P. clivosa. 

A pair of superior pharyngeal bones from the Washakie basin of the 
Bridger formation strongly resemble those of this species. 

Peiscacara serrata Cope. 

Bulletin U. S. Geol. Siirv. Terrs., 1877, p. 816. 
Plate XIII, fig. 1. 

Form a regular wide oval, with a subequal contraction at both extremi- 
ties. The spinous dorsal rays become longer than the soft ones, but the 
posterior spines are shorter than the anterior soft rays, so as to produce a 
wide emargination in the superior outline. The spines are very robust, 
especially those of the pectoral and anal fins. The first anal spine is near 
two-thirds the length of the second. The pectoral fin does not extend to 
the anal, and the soft parts of the anal and dorsal, which are equal, do not 
overlap the base of the caudal. Radii : D. X— 11 ; A. Ill— 10; C.?— 17— ?. 
Vertebrae: D. 9; C. 14. The centra have a strong median lateral ridge, 
which separates two fossae. 

The greatest depth is at the base of the ventral fins, or the third dorsal 
spine; it enters the total length (with caudal fin) two and four-tenths times. 
The length of the head enters the same three and four-tenths times. The 
orbit is large, its diameter exceeding the muzzle and entering the length of 
the head a little over four times. The mouth is terminal, and the premaxil- 
lary extends obliquely downward and backward; the maxillary reaches the 
line of the anterior border of the orbit. 

The scales are longet* than deep, and the rough surface has but a small 
extent, and is finely granulated. The remainder of the scale is marked 
with strong concentric grooves. Those on the gular region are small On 
the belly, there are from twenty to twenty-five rows (about) below the ver- 
tebral column. A row of scales extends along the postero-inferior edge of 
the operculum. This part is well preserved in only one of my thi-ee speci- 
mens which represent the species. 



Total length 217 

Length of head 0G4 

Length to line of first spine of first dorsal 070 

Length to line of first spine of second dorsal 121 

Length to line of anal 122 

Length to baKC of caudal 173 

Depth at first dorsal spine 093 

Depth at tirst dorsal soft ray 070 

Depth of caudal peduncle 027 

Length of fourth dorsal spine ^ 03© 

Length of second anal spine 027 

This species is about the size of the Crappie, Pomoxys annularis. Not 
rare at Twin Creek, Wyoming. 

Priscacara ctpha Cope. 

BuUeHn U. 8. Geol. Surv. Terrs., 1877, p. 817. 
Plate Xni, fig. 2. 

This species is nearly related to the last, but presents a number of 
differences which require its separate consideration. These are: (I) The 
more arched or convex dorsal outline; (2) The relatively longer head ; (3) 
The presence of an additional dorsal spine; (4) The entire covering of the 
operculum with scales. There is also probably a smaller number of dorsal 
vertebrae, but this is not certain, as that region has been somewhat disturbed. 
Foi-mulse:— Rays: D. XI— lU— 11; A. 111—9; P. 15. Vertebrae, 6-14. 

The greatest depth enters the totiil length 2.6 times ; the length of the 
head enters the same 3.3 times. The spines are more robust, and the ser- 
rature of the preopercle more produced in the individual now described 
than in any of those of the P. serrata in my possession. The size is about 
the same as that of the latter species. 

Twin Ci-eek, Wyoming. 

Priscacara oxyprion Cope. 

Bulletin U. S. Geol. Surv. Terra., 1878, p. 74 (Febmary 5). 
Plat* XIV, fig. 5. 

Five specimens in nearly complete preservation represent this species 
in our collections. It is more nearly allied to the P. serrata than to the 
other species, as the spine of the ventral fin is large and robust. It differs 


from that and from all the other known species of the genus in the small 
number of the radii of its anal fin. It agrees with P. serrata in the small 
number of the rays of the second dorsal. It is a smaller species than the 
P. serrata, being intermediate in size between it and the P. pealei. It is 
especially marked by the long, acute serrse of the entire posterior and infe- 
rior margins of the pi-eoperculum. The operculum, suboperculum, and 
cheek are scaled ; the preoperculum is naked. 

Formula: Br. VIII; D. X— 11; V. 1—5; A. Ill— 8 ; Vert. D. 10; 
Gaud. 14. The form is an elongate oval, rather more elongate than any 
other species of the genus. The mouth is terminal and the front gently 
convex and descending. The length of the head enters the total, less the 
caudal fin, two and a half times, and the greatest depth is half of the same. 
The dorsal spines are long and strong, the longest equaling the soft rays in 
length. The anal spines are very robust, the second or longest not equaling 
the longest soft rays of the same fin. The origin of the first spine is below 
the first ray of the soft dorsal. There are three long and one short inter- 
neural bones in front of the dorsal fin. The origin of the ventral is below 
the third (or fourth) dorsal spine. The vertebrae have two fossse on each 
side, separated by a ridge. The jaws are edentulous. The scales are small 
and the specimens very well preserved. 

In the largest specimen, I count, in a vertical line drawn from the first 
dorsal soft ray to the middle of the abdominal line, fifteen longitudinal rows 
of scales above, and twenty -five below, the vertebral column. On the opercu- 
lar flap of a smaller, the typical specimen, I count nine vertical and fourteen 

transverse rows of scales. 



Length of type-specimeu 137 

Lengtli to base of caudal fin = 109 

Lengtli to apex of first interhsemal 067 

Length of head 040 

Length of third dorsal spine 024 

Length of second anal spine 018 

Length of pectoral spine — 019 

Depth at first dorsal spine 050 

Depth at first anal spine 041 

Depth of caudal peduncle 019 

The lateral line is visible in the largest specimen. It extends parallel 
to the dorsal border, marking at its greatest convexity less than one-third 


the distance from the vertebral column to the dorsal outline. It disappears 

behind the vertebral column below the seventh soft dorsal ray, and does not 


This fish came from a deposit of the Green River Shales on Twin Creek, 


Priscacara clivosa Cope. 

Bulletin U. 8. Geol. Snrv. Terra., 1878, p. 76. 
Plate XIU, fig. 3. 

In the last-named fish, there are eight dorsal and fourteen caudal ver- 
tebrae. Radii: D. X — 13; A. Ill — 11. The ventral fin appressed, nearly 
reaches the base of the anal, a point in which it difi'ers materially from the 
two allied species. Another characteristic is the form of the profile, which 
resembles that of some of the species of Geophagiis. This descends steeply 
from a point just anterior to the base of the dorsal fin, giving an obliquity 
to tliat part of the outline, and an inferior position to the mouth. The ver- 
tebral column is more arched anteriorly, appropriately to the prominence of 
the anterior dorsal region. The depth at the base of the first dorsal fin 
enters the total length (with caudal fin) 2.6 times, and the length of the 

head 3.6 times in the same. 



Totallength 115 

Axial length of head 032 

Axial length to line of first dorsal 032 

Axial length to origin of ventral fin 041 

Axial length to origin of anal liu - 057 

Axial length to origin of second dorsal fin 056 

Axial length to origin of caudal fin 082 

Depth of caudal peduncle 016 

The preopercular border is not visible in the only specimen of this 
species known to me. The operculum is scaly. There are 11-13 rows of 
scales on a line from the vertebral column to the abdominal border. 

Twin Creek, Wyoming. 

Priscacara pea lei Cope. 

Ballotin U 8. Geol. Surv. Terrs., 1878, p. 75. 
Plate VIII, fig. 4 ; XIV, fig. 4. 

Outline elliptic, with the extremities contracting equally or symmetri- 
cally to the head and tail. Depth at ventral fins entering length (with 


caudal fin) 2.60 times. Mouth rather small ; length of head entering total 
length 3.8 times. Short conic teeth en brosse. Preorbital and preopercular 
bones finely serrated on their free margins. Vertebrae: D. 7; C. 14. Radii: 
D. X — 14; A. Ill — 11; V. I. 5 or 6. The dorsal spines are rather slender; 
the anal spines are stouter, but shorter; the ventral spine is weak and 
slender. The ventral fin when appressed against the belly fails to reach 
the anal fin by a space a little greater than the length of the ventral spine; 
its origin is beneath the third dorsal spine. The scales are difficult to 
observe on the specimens, but there are not less than fifteen to seventeen 
longitudinal rows along the abdomen in front of the anal fin. 

Measurements. m. 

Total length 130 

Axial length of head 035 

Axial length to first dorsal spioe 038 

Axial length to first dorsal soft ray 062 

Axial length to first anal spine 070 

Axial length to base of caudal fin 103 

Depth at orbit 025 

Depth at first anal spine 041 

Depth of caudal peduncle 016 

Length of fifth dorsal spine 019 

This species is similar in size and proportions to the Priscacara Hops, 
but difi"ers in having constantly but seven dorsal or abdominal vertebrae, 
while that species presents nine. I have not observed any serratures on the 
preoperculum of the P. Hops, but the typical specimens are imperfect in that 
region, although good impressions of it remain on the matrix. 

Two complete specimens present all the characters of this species, 
while in two others all the more important ones can be seen. Two addi- 
tional specimens may be referred to it with the greatest probability, and I 
have found it abundant in various collections. Some were obtained by Dr. 
A. C. Peale, in charge of one of the parties under Dr. F. V. Hayden, from 
the shales of the Green River formation of Wyoming. The species is dedi- 
cated to Dr. Peale, in recognition of his services to geological science. 

Pkiscacara liops Cope. 

Bulletin U. S. Geol. Surv. Terrs., 1877, p. 818. 
Plate XIV, figs. 2-3. 

A smaller fish than either of the preceding is referred to this genus, 
although it differs in one feature, regarded as important among the Poma- 
7 o 


centrida:, i. e., the preopercular border is entire. It conforms closely to the 
P. serrata in other resi^ects, as the form of the dorsal fin, three anal spines, 
form of caudal fin, character of scales and lateral line, edentulous jaws, 
and, indeed, in form to such an extent as to lead me to suspect that in this 
genus, as in Lepomis, etc., the seri-ation of the prcopercle is not of much 
systematic value. One character by which the P. Hops may be distinguished 
from P. serrata, in addition to the smooth preoperculum and small size, is 
the constantly larger number of rays in the second dorsal fin. 

Formula?:— Rays: D. X— 13-14 ;C. 5—19—6; A. III. 10-11. Verte- 
bra;: D. 9; C. 13. The pectorals originate below the first dorsal spine, and 
the ventrals a little behind it. The spines are moderately stout, and the 
emargination of the dorsal fin is not deep. There are twenty -five rows of 
ctenoid scales traversed by a vertical line from the middle of the spinous 
dorsal, and smaller scales cover the operculum and more or less of the pre- 



Total length 113 

Length of head 0;!"3 

Length to firat dorsal spiuc .0:54 

Length to first dorsal soft ray 0.'>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 


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. 



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 


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. 


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. 



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. 


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 




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. 


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- 

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. 



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, 

* American Journal Science and Arts, 1871, May. 



Cope, Proceedings Academy Phila. 1376, p. 350. 

Vertebral centra amphiplatyan. Processus dentatus free from axis. 
Neural arches separate from centrum during maturity. 


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- 


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. 


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 

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. 


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. 


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 

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. 



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. 


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. 


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 . 


( 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. 




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. 



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. 


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. 


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. 


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<l. I'liila., Oct., 1*76. 



Cope, Proceedings American PhiloBophical Society, 1870, p. 559. 
a Vertebral bones and scuta normal. 

One intergular scutum entirely separating the gulars Adocus Cope. 

Either two intergulars, or the gulars meeting behind intergular Amphiemys Cope. 

a a Vertebral bones wedge-shaped, widening upwards ; verte- 
bral scuta not wider than the bones. 
Elements of carapace early coossifled Eomorhophus Cope. 

„ ^ , ^ Emydid^. 

a No scutal sutures. 

Surface sculptured Apholidemys Pom. 

a a Scuta including intermarginals and two anals. 

Lobes of sternum narrow Dermatemys Gray. 

Lobes of sternum wide Agomphus Cope. 

a a a Scuta ; two anals, no intermarginals. 

Surfaces of carapace sculptured ; plastron fixed Compsemys Leidy. 

Surfaces of carapace smooth ; plastron fixed ; recent Hmydidce* and 

the genus Emys Brong. 

Posterior lobe of plastron moveable; surfaces smooth Ptycliogaster Pom. 

a a a a Scuta ; One anal, no intermarginals. 

Carapace smooth ; pectoral plates entire Stylemys Leidy. 

Carapace smooth ; pectoral plates small, widely separated from each 

other Manuria Gray. 

„ , . TESTtTDINID^. 

a Two anal scuta. 
Ten abdominal scuta Hadrianus Cope. 

a a One anal scutum. 

/9 Claws 4-4. 

Jaws with aveolar grooves Testudinella Gray. 

Lower jaw smooth ; upper with a ridge Homopus Dum. Bibr. 

/9 /9 Claws 5-4. 

Y Hinder part of carapace mobile. 
Gulars distinct Kinixys Wagl. 

;- y Hinder part of carapace fixed. 

S Plastron moveable in front. 
Gulars distinct Pyxis Bell. 

$ S Plastron fixed. 

Gular plates united Chersina Gray. 

Gular plates distinct. 

Lower jaw with two cutting edges Xerobates Agass. 

Lower jaw with one cutting edge. Testudo Linn. 

The extinct tortoises of the Cretaceous and Eocene throw considerable 
light on the probable origin of various existing genera,t and while much 

* Gray has distinguished several genera among existing species, on cranial characters. 
tSee on the Extinct Tortoises of the Cretaceous of New Jersey. Proceed. Amer. Ass. Adv. Sol., 
1871, p. 344. 


remains obscure, the following observations may be derived from the study 
of the forms in question. 

The order makes its appearance in the Triassic period, for I am assured 
by Dr. F. Endlich, of Reading, Pa., that the species obtained by Professor 
Quenstedt, in Wiirtemburg, belong undoubtedly to the Testudinata. With 
their special structure we are not yet fully acquainted. A number of genera 
appear in the Jurassic, and there is a successive increase in the number of 
species in the Cretaceous and Tertiary formations. Sphargis, which is with- 
out carapace, and has a greatly reduced plastron, may be regarded as 
nearest the primitive types of the order. One species, S. pseud ost radon, 
has been found in the European Jurassic, and the genus exists in recent 
seas. Protostcga of the Kansas Cretaceous is its nearest extinct ally known. 
Protostega is superior in the well- developed marginal bones, and prepares 
the way for consideration of the genera with incomplete shields, of the pres- 
ent period {Cheloniidce), which also possesses the natatory extremities. Two 
structural features of importance mark many of the Jurassic forms. First, 
the incomplete union and ossification of the elements of the plastron and 
carapace; second, the reduction in size of the lobes of the plastron. Genera 
retaining some or all of these peculiarities persist to the present day, but 
the ossified types with wide plastron are far more abundant, and are com- 
paratively rare in the period of the Jura. 

Trionyx appears to represent another point of departure. Its plastron 
presents a grade of development near to that of Propleura, and its eight 
costal bones ally it to other types. In its half-ossified carapace wanting 
the marginals, it is inferior to both. It leads us at once to the existing Chcly- 
dra, the closing of the sternal fontanelles being accompanied by a contrac- 
tion of its extent in respect to the bridges and lobes. In Propleura of the 
Cretaceous we have a state of things intermediate between some of the 
Jurassic Chelydridcc, as Idioclielys, and Chelone. These genera had a common 
origin near the Jurassic predecessor oi Protostega. The peculiar sculpture of 
Trionyx IS seen in the Eocene Anostira (which is much like CJielydra in form), 
and in an obsolete condition, in Adocus of the Cretaceous, which adds 
Chelydrino and Pleurodire characters in a remarkable manner. It is closely 
joined by Pladomenus, which, in turn, presents points of resemblance to 



The Jurassic genus Aplax Myr., is nearly as deficient in ossification of 
carapace and plastron as Protostega, and is allied to the Chelydrid series, 
which existed cotemporaneously and during the Cretaceous. Idiochelys 
represents a rather more advanced form, with distinct marginal bones, and 
with affinities to Chelydra of a decided character. It was probably its 
ancestor. Allied to it we have such forms as Adocus and Baiina, which, 
while furnished with fully ossified shell, still approach Chelydra in the 
contracted form of plastron, and have several points of afiinity to the 
Pleurodire series. From some common ancestor of these, sprang also the 
true Pleuroderes of the Cretaceous, as Taphrosphys, while, by the omission 
of most of the tendencies towards that series, we have Dermatemys, the 
genus of EmydidfB neai-est to Adocus. From this point we pass to true 
Emydidce, and thence, by the loss of a series of phalanges, to Testudo. From 
Taphrosphys we pursue the Pleurodire series to the similarly modified type 

The accompanying table expresses the relations indicated, supposed 
to b§ genetic, and in accordance with the theory of evolution. (Types 
beginning in the Jurassic in italics; Cretaceous to recent, small capitals); 
Eocene to recent, spaced; recent only, Roman. The apparent reversal 
of the order of time displayed by the Jurassic and Cretaceous families is 
an indication of our ignorance of the Jurassic Testudinata. 
Cistudinidae. Cmosternidse. Pelomedusidse. Chelydidae. PoDOCNEMiDn>.aE. 

udinidae. Hydraspididse. 





Cheloniid^. Pbopleukid^. 


Sphargididce. Pbotostegid^. Trionychidte. 




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 


deposits, as in woven linen The cervical vertebra is without spine; it is 
not depressed in the middle, and is without any pneumatic foramen. 


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. 


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 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 together, interrupted and vermiform .... T. ventricosux. 

II. Sulpture of the extremities of the costal boues honeycombed or 


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. 


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. 



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 


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. 

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. 



Width of (■■ara])ace at antepenultimate 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 


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. 



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. 



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 


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. 


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 


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 


■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. 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. 



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 


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 



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- 


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. 



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 



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. 


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. 


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. 



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. 



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 


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 



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. 


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. 



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 


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. 


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. 




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 


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. 


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. 



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 


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 


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 

'Report U. S. Geol. Surv. Terrs., i, 1873, p. 140. 


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. 



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^, ' " 




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. 


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 




Lonpth of third vertcliral bono -.045 

Widtb of third vert*3brul bono 0;«) 

I.iMiRlli of third 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. 

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. 



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. 


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 

In old specimens this delicate sculpture might become obsolete. 



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. 



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. 


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 


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. 



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- 



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. 


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. 


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 


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- 



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. 


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 

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 

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 

There are prominent axillary and inguinal septa, as in some Emydidce^ 


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 


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. 



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. 


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 


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. Acu<l. Phila., 1870, p. IM'J. Keport U. S. Geol. Surv. Tuits., i, p. 161, pi. xvi an<l xx, figs. 1-5 
anrl xiii. 11. affniis Leidy, ADnunl Report U. 8. Geol. Surv. Teirs., 1871, p. 367. 

Plate XVIII, figs. 1-2. 

A perfect specimen of this species is of smaller size than those of the 
preceding, and about equal to the Bseudcmys rugosa, and not dissimilar in 

The carapace is strongly convex, and all its component parts, as well 
as those of the plastron, are coossified. The sutures of the intersternal 


bones are visible. The posterior end of the carapace is arched upwards 
and smoothly excavated ; the postero-lateral borders are thin, and deeply 
notched at the ends of the scutal sutures. Similar but shallower emargina- 
tions mark the borders of the marginal scuta. The anterior margin is 
slightly concave. The lobes of the plastron are narrow, the posterior 
Avider and slightly emarginate. The bridge is wide, and not more than 
half as long as the width of the base of the posterior lobe. 

The general surface is minutely rugose or shagreened, on the plastron 
strongly so, and without other sculpture. The carapace is marked by strong 
gToo\es disposed in a regular manner. A double groove extends along the 
median line of the second, third, and fourth vertebral scuta. Other grooves 
are nearly parallel to this one, whose extremities diverge to the angles of the 
vertebral scuta. At the anterior angles of the costal scuta oblique grooves 
converge towards the vertebrals, and are continued backwards as parallel to 
the median line. They are separated by parallel tuberosities. On the fii'st 
and last vertebral scuta there are transverse grooves next the adjacent verte- 
brals, and longitudinal ones towards the margins of the carapace. 

The scuta are well marked. The marginals are all longer than wide 
except the four preceding the last, which are all wider than long. The last 
is suboval, and is very small, while the anal is altogether wanting. The 
nuchal is divided (it is single in B. hebraica), the first marginal is very 
small and projecting, the third is longer, while the fourth, fifth, and sixth 
are rather short. The vertebral scuta are all longer than wide, and the 
fourth is deepl}- emarginate to receive the last scute. The first is a broad 
triangle with anterior angle truncate, and the two basal ones cut off to a 
less degree. 

The scutal sutures of the plastron are but little sinuous. The inter- 
gulars have precisely the form of gulars of Emydes. The posterior gular 
suture crosses the median line a short distance posterior to those of the 
intergulars, and each half consists of an obtuse V directed backwards. The 
posterior humeral suture originates in front of the axilla. There are four 
intermarginal scuta on the one side and three on the other, the additional 
one being a small one behind the left axillaiy. The femoro-anal suture is 
nearly straight. 




Length of carapace (axial) 450 

Wiilth of canipaco (axial) 240 

Length of i)lasl ron 290 

Length of anterior lobe 082 

Length of posterior 085 

Width of extremity of anterior lobo 038 

Width of extremity of posterior lobe 057 

Length of nuchal sent a 030 

Length of tliinl marginal 023 

Width of thiril marginal 020 

Width of fonrih marginal 024 

Length of fonrth marginal 028 

Length of right h marginal 030 

Width of .-ighth marginal 035 

This species differs in many details from the preceding species, notably 
in the forai of the marginals The anterior are wider than in either species, 
while the median are narrow as in B. undata. The sculpture is very distinct 
from that of either. 

From the bad lands of Ham's Fork, Wyoming. 

Baena ponderosa Cope. 

Annual Report U. S. Geological Survey of the Territories, 1872 (1873), p. 624. 
Plate XVIII, figs. 3-8. 

Established on numerous fragments of a specimen of a species which 
I cannot refer to this genus with certainty, but which agrees with the species 
already known in some particulars of structure. Thus, the last marginal 
plates were separated by an excavation of the posterior border; at least this 
is the only position to which I can refer a portion of the margin of the cara- 
pace where the marginal scutes suddenly cease. The lateral ribs of the 
bridge are received into a deep pit between two costals. 

The marginal and other bones are very massive, much more so than 
in any other known water tortoise of this formation ; the margins of the 
former are thickened, especially at the last marginal scute, which is on a 
massive protuberance. The sutures are entirely regular. The lateral 
marginal scuta are about as long as broad. The surface of the shell is 
marked with irregular impressions, which are sometimes like rain-drop pits. 
A posterior vertebral bone possesses a median rib similar to that in Dernia- 
temys vijomingensis. 




Length of an anterior marginal scute 045 

Width of an anterior marginal scute 039 

Thickness of bone at anterior marginal scute 023 

Length of a free marginal bone 050 

Width of a free marginal bone 057 

Length of first marginal of bridge 060 

Thickness at simple end 023 

From the bad lands of Ham's Fork, AVyoraing. 


The fauna of the Eocene periods of the United States inckided a num- 
ber of species of Crocodilia, some of which were represented by great 
numbers of individuals. They were equally numerous in the Wasatch and 
Bridger epochs, but none have been found in the Green River fomiation 
proper. They are moderately abundant in the Wind River beds, and a 
species is known from the Manti beds of Utah. None are known from 
the Miocene formations west of the Rocky Mountains, and but one species 
from that formation to the east of them ; but they are not rare in the marine 
Miocene of the Atlantic coast. All the species belong to two genera, Diplocy- 
nodus Pomel, and Crocodilus Linn. One species of the former is found in 
the Wasatch beds, with three or four species of Crocodilus. In the Bridger 
beds I know of six species of the latter genus. 


The Eocene species of true crocodiles differ much in size and characters, 
ranging from the C heterodon, which is not larger than an Iguana, to the 
C. clavis, which rivals the existing species of the East Indies. 

The species are divided into two sections, which are distinguished by 
the form of the frontal bone. In the one it is thin, and has low lateral olfac- 
tory crests. Such species are as yet only known from the Wasatch forma- 
tion. They are the G. grypm Cope and C. wheeleri Cope. Thq. species of the 
second section have massive frontal bones with strong lateral olfactoiy 
crests. The C. chamensis and C. heterodon of the Wasatch belong here ; 
also the C. eUiottii of the Bridger and the C. clavis of the Washakie forma- 
tion. The frontal bones of C. subulatus and C. polyodon of the Bridger are 


unknown. I distinguish the species described in the succeeding pages by 
the following characters, among others : 

Teeth with coarse sulci at the base only ; crowns long C. subulatus. 

Teeth with liner deep sulci extending towards the apex of the robust 

crown C. sulci/erus. 

Teeth acute, compressed; crowns with numerous shallow sulci; muzzle 

slender ; no distinct ledge or smooth space on frontal hone G. acer. 

Teeth without sulci, crowns robust; frontal bone with a transverse ledge, 

with a smooth space in front of it ; premaxillaries conical C. affinis. 

Teeth without sulci; frontal without ledge, honeycombed; premaxillary 

teeth conical C. clavis. 

Teeth without sulci; front plane, honeycombed; premaxillary teeth com- 
pressed, trenchant ; size small C. heterodon. 

Crowns of teeth unknown ; sizes very irregular, numerous small teeth 

with a few large ones interspersed .... G. polyodon. 

The C. affinis and C. elliottii belong to the section oi* genus Thecachampsa 
Cope, which is characterized by the concentric structure of the teeth They 
are composed of layers, which fonn a cone-in-cone structure, each cone 
being distinct from the one which it incloses. I do not know the structure 
in the other species above named. 

I have formerly referred two of the species, the C. subulatus and G. 
polyodon, to Diplocynodus Pom, a genus characterized by the presence of 
two similar and adjacent canine teeth in the ramus of the mandible. C. 
subulatus has two such canines in the upper jaw, but there is no eNidence 
that there are such present in the lower, as the mandible is broken off an- 
terior to the canine which is present. 

The typical specimen of C. liolyodon is broken in the same manner, so 
that I leave it also provisionally in Crocodilus. 

Crocodilus subulatus Cope. 

CrocodUuK (Ichlhi/osuchwi) mihulatuii Cope, I'rocecMl. Anier. Pliilos. Si>o., 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 


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. 



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 


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. 



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, 


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. 


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. 



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<!nor table at < ' , , 

( squamosal angles 126 

Vertical diameter of skull ^ "^'"'"'""^"•"♦''l ''°"'ly'« •^*- 

c below occipital condyle 034 

Width of extremity of osquadratum 033 

Width of posterior nares 014 

Width of inferior orbit 031 

Length of inferior orbit 095 

This species is smaller than the C. affinis, to which it is generally allied. 
It has a slight trace of the ledge between the anterior borders of the orbits 
seen in several of the Bridger species. The forms and sculpture of the 
teeth are entirely different from those of the C. elliottii and allies. In life 
the species had about the size and form of head of the nairow-nosed caiman 
now living in South America, Jacare jnmcttdata Natt. 

My only specimen of the CrocodUus acer was obtained by Charles H. 
Sternberg, from the white limestone near Manti, in central Utah. Other 
specimens have been subsequently found. This formation belongs to the 
Eocene period, but its exact relation to those on the east side of the Wasatch 
Mountains is yet uncertain. I have called it the Manti formation. 


Crocodilus sulciferus Cope. 

Proceed. Aiuer. Philos. Soc, 1872, p. 555 (October 12). Annual Report, loe. cit., 612. 

Plate XXIV, fig. 23. 

The specimen on which this species was established included various 
portions of the skull and skeleton, which were of about the size of corre- 
sponding parts of the C. elliottii. The characteristic teeth were removed for 
purposes of description and illustration, and it has unfoi'tunately become 
impossible to identify the specimens with which they were originally asso- 
ciated. I can therefore at present only reproduce the description originally 

A medium-sized species with cranium deeply and roughly pitted. The 
chief character is at present visible in the teeth. The larger of these are of 
subcylindric and short conic crown, which is supei-ficially grooved from, 
basis to near apex; sulci coarse, open, but close together, and separated by 
strong narrow ridges. 

From the Bridger bluffs of Upper Green River. 

Crocodilus clavis Cope. 

Proceed. Amer. Philos. Soc, 1872, p. 48."i. Paleontological Bulletin No. 6, p. 3 (August 20). 
Plate XXI, fig.s. 4-9; Plate XXII. 

This large species is represented primarily by a portion of a cranium 
with vertebrae, of a specimen which I found in the Maumioth Buttes of the 
Washakie basin, near South Bitter Creek, Wyoming. A portion of this 
specimen has been, through the vicissitudes of a moving, mislaid; but enough 
remains to furnish determinative characters. Some time subsequently I 
obtained from the same region a nearly complete skull, accompanied by 
various parts of the skeleton, which I refer to the same species. I now 
give the original description of the type The muzzle of this species is of 
narrowed proportions, and sufficient depth to give it a broad, oval section. 
The nasal bones appear to have reached the nareal orifice. The anterior 
superior teeth are very large, especially the canine. The inferior tooth 
corresponding is large, and occupies an emargination which approaches 
near to the nasal suture. The pitting of the muzzle is fine, and the swollen 


interspaces much wider. The teeth have stout conic crowns, with well 
developed cutting edges and coarse striate sculpture. The mandible is 
acuminate to the narrow extremity, and has a long symphysis which extends 
to opposite the third tooth behind the notch. The cervical vertebrae preserved 
have round cups; they have a simple elongate hypapophysis, with a pit 
behind it ; .•shoulder very prominent. 



Length of ritiiiiis with teeth 

Lengt h of Bjiuphysis 135 

Width of ramus at end of symphysis 083 

Width of ramus at cud of mandible 020 

Width of maxillary at third tooth above 0"20 

Width of maxillary at notch above 020 

Portions of a few vertebree are preserved. An anterior cervical has a 
massive hypapophysis whicli connects the two parapophyses. Its quadrate 
base is thickened posteriorly ; as the apex is broken off it is impossible to 
ascertain its length. Immediately behind it on the middle line is a deep 
fossa like a foramen. On the middle of the posterior shoulder below, is a 
low, acute tuberosity ; the shoulder is very prominent, and its sides are 
slightly i-ugose. The cup is subround. A posterior dorsal has a capitular 
costal surface extending vertically. The cup is a little wider than deep, 
and the base indicates a strong hypapophysis. The face of the posterior 
shoulder of another dorsal is much roughened by closely placed ridges and 
small tubercles. 

Mcamtrements of vertebrw. 


Li-ngth of cervical (28 lines) 061 

vertical 032 

transverse 032 

vertical 035 

transverse 040 

Width of femoral condyles 064 

e ve 

Diameters of cup of cervical I 

} tri 

Diameters of cuj> 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 


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 


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. 


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 


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:. 

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- 


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 

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 

One readily observes that the frontal and j)arietul regions of the skulls 


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 

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. 


Meagurementu of skuU. 


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. 


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 


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 

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 


The vertebral centra found with other specimens are round. The 
coossified neural arches indicate the adult age of the animal. 


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 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 


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. 


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,'>. 


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 

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 

Astragalus articulating with both cuboid and navicular Biplaethra. 


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. 


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 

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. 


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). 

/ ^ 





^ / 




/ 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 


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. 


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 


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 

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. 


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. 



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. 


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. 


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 


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) 

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. 



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 



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* 


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. 


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. 


wanting:. The positions coiresponding to their 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 


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 


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 


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 : 



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- 


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. 


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 



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. 


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. 



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 



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. 



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 


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. 



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. 



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 th at some o f the 
types whichXtave referred here may turnj)ut to be Marswpialia^ hut jhe^ 
number of such cases is pro bably s piall. . The following is the definition of 

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. 


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 Prosimi<je. This ancestry is rendered 
almost certain by the discovery, by Drs. A. Milne Edwards and Grau- 
didier, of the affinity existing between the Prosimio' and the Carnivora. 

Before the discovery of the species and genera which form the subjects 
of this report, I wrote as follows: "I trust that I have made it sufficiently 
obvious that the primitive genera of this division of Mammals must have 


been Bunodonts with pentadactyle plantigrade feet. We may anticipate the 
discovery of such a genus, and believe that it will not be widely removed 
from the Eocene Hyoj^sodus, or perhaps Achcenodon. But it will be more 
than this: it cannot be far removed from the primitive Carnivora and the 
primitive Quadrumana. The Carnivora are all modified Bunodonts, and the 
lower forms (Ursus, Procyon, etc.) are pentadactyle and plantigrade; as 
to the Quadrumana, man himself is a pentadactyle plantigrade Bunodont* 

Such a hypothetical type might be expressed by the name Bunotheriidce, 
with the expectation that it will present subordinate variations in premolar, 
canine, and incisor teeth. The premolars might be expected to differ in the 
degree of development of the internal lobes, the canine in its proportions, 
and the incisors in their number." 

The history of discovery of the Eocene forms of this order is briefly 
told. Professors Leidy, Marsh, and myself had described Creodonta as 
Carnivora, until I pointed out, in some remarks before the Philadelphia 
Academy (published December 22, 1875) their true relations. The first 
species of Tillodonta was described by Leidy from an inferior molar from 
New Jersey, in 1868. Dr. Leidy next described the dentition of the mandi- 
ble of the same genus from Wyoming. Subsequently, Marsh described the 
superior molars of an allied genus, from Wyoming. In 1874, the writer 
described the dentition of the Tceniodonta from specimens collected by Lieu- 
tenant Wheeler's Survey in New Mexico. In March, 1875, Marsh proposed 
the Tillodonta as an order of Mammals, giving its dental characters, and 
stating the brain was small. In December, 1875, in his remarks on Creo- 
donta, I referred this group to the Insectivora as a suborder. In March, 
1876, Professor Marsh gave a full description of the cranial characters of 
the genus Tillotherium, describing the characters of the brain from a cast of 
the cranial cavity. In the same month of 1876 the writer characterized the 
suborder Tceniodonta, referring to it the genera JEctoganus and Calamodon. 


The Tceniodonta agree with the Tillodonta in the possession of a pair of 
inferior incisors of rodent character, but it adds several remarkable pecu- 

*0n the Homologies and Origin of the Types of Molar Teeth of Mammalia Educabilia, Journal 
Academy Philadelphia, 1S74, p. 20. 


liaritieR. Chief amonfr these is the character of tlie inferior canines. Tn the 
TiUoihnta tliey are either wanting, as in Erinacetts, according to the Cu\'i- 
erian diagnosis, or they are insignificant. In Cahniodon they are of lai-ge 
size, and tliough not as long-rooted as the second incisors, grow from jier- 
sistent pulps. They have two enamel faces, the anterior and posterior, the 
former like the corresponding face of the rodent incisors. The function of 
the ailult crown is that of a grinding tooth. This character distinguislies 
Cahutiodon as a form as different from Tillotherium as the latter is from 
Esthonyx. There are, however, other characters. The external incisors, 
wanting in Tillolhcriiim, are here largely developed, and though not growing 
from persistent pulps, have but one, an external band-like enamel face. 
TIrIt function is also that of grinders The fact that the rodent teeth in the 
lower jaw are the second incisors, renders it probable that those of the Tillo- 
donta hold the same position in the jaw. This is to be anticipated from the 
arrangement in Enthoni/x, where the second inferior incisors are much larger 
than the first and third. The superior dentition of the Taniodonta is unknown. 

Two families represented this suborder in the Eocene period of North 
America. The first or Ectoganid<z, with two species, possess molar teeth 
with several roots. In the Calamodontidcp, with five species, each lower molar 
has a simple conic fang. The great reduction in the extent of the enamel 
investment is an interesting approximation to the Edentata, where this sub- 
stance is altogether wanting. The reduction is greatest on the adjacent sides 
of the molars; it has a little greater extent on the inner side, while it extends as 
a band on the exterior side, so that in worn teeth this surface alone remains. 
In addition, there are a heavy cementum investiture and undivided roots in 
the genus Calamodon, features essentially characteristic of the Edentata. 

Thus we have in the Tceniodonta the first hint as to the relations of the 
Edentata in early Tertiary time. 


Eeiiort Vert. F088. New Mexico, U. S. Geog. Surv«. W. of 100th M., 1874, p. 5; Id.. Ann. Report U. S. 
Geol. SiirvB. W. of UKltli M., Iii74, p. 117; System. Cat. Vert. Koiene N.-w M<-xico, U. S. Geog. 
SurvB. W. of 100th M., le7o, ji. 24 ; Keport U. S. Cicog. Survs. W. of lOotli M., vol. iv, pt. ii, 1S77, 
p. 162. 

Fornnila of inferior dentition, I. 8; C. 1, M. 5; without distinction into 
premolars and molars. First incisors small, with conic roots; second inci- 


sors rodent-like, ver}' large; third incisors large, with conic roots, faced with 
enamel in front only. Canines placed obliquely to the long axis of the 
ramus, their long horizontal axis extending inwards and backwards. Enamel 
confined to their narrow anterior and posterior faces. Molars subcylindric 
and with conic roots, one or more of them within the base of the coronoid 
jjrocess. Form of the jaws deep and robust. 

A characteristic feature of the dentition in this genus is the thick coat- 
ing of cementum, which invests those portions of the molars and inferior 
canines which are not protected by enamel. In these teeth it is thicker 
than the enamel, and forms thickened raised borders surrounding the latter, 
producing a characteristic appearance not known in the other genera." It 
is not observable in the large inferior incisors. 

A part of the skeleton of one of the species is preserved. It shows 
that the humerus was robust, and was pierced distallj^ by a large arterial 
foramen The condyles are not very convex, nor the internal epicondyle, 
so prominent as in some of the Creodonta. The head of the radius is flat 
and incapable of rotation, and the shaft is rather slender, while the ulna is 
deep and thin. An ungual phalange is stout and compressed, and but little 
curved, and without the basal sheath seen in some Carnivora and Edentata. 

The exact homologies of the seven mandibular teeth are obscure, and 
it is uncertain to how many the expression molar should apply, since the 
wear of all in my specimens is nearly equal 

The synq)hysis is solid and long; it projects wedge-like between the 
large incisors, whose anterior borders are closely approximated. Tliere is 
a largo mental foramen. 

Two species, the C. arcamcenus and C. simplex, were found by myself in 

New ]\Iexico. A third one, discovered by Mr. J. L. Wortman in the Wind 

River beds, has been described by myself under the name of C. cijlindrifer; 

it is not sufficiently well preserved to settle finally the question of its generic 


Calamodon simplex Cope. 

Report Vert. Foss. New Mexico, U. S. Geog. Surv. W. of lOOtb Meridian, C.apt. G. M. Wlieeler, 1874, p. 
5. Repi rt U. S. Geog. Siirvs. W. of lOOtb Mcridi.iu, Capt. G. M. Wheeler, 1874, iv, ii, p. 166. 
PI. xlii, figs. (V-S; xliii; xliv, figs. 2-5. Pal. BiiUetiu No. 34, p. 147, 1882. 

Plate XXIV c. Fig. I. 

The nearly complete mandible of this species was obtained by J. L. 


Woitman in the Wasatch Bed-lands of the Big Horn Basin of Northern 
Wyoming. It has furnished the information necessary to complete our 
knowledge of the inferior dentition of the genus. It indicates an animal 
of the size of a tapir, and with a very peculiar physiognomy. This is due 
to the shortness and depth of face, as indicated by the lower jaws. 

If the anterior border of the coronoid be held vertically, the masticat- 
ins: surface of the molars is horizontal. The inferior border of the ramus 
descends steeply to below the second molar, and then rises to the level of 
the grinding surfaces in a curve which is the arc of a circle. This curve 
follows the external border of the second incisor, which terminates at the 
fundus of its alveolus, below the third molar. The ascending inferior bor- 
der is gently concave below the coronoid process, and passes into the widely 
convex angle, whose middle is about in the line cff the alveolar edge of the 
jaw. The condyle is pretty well elevated. Its articular face descends 
gently inwards, and its convexity looks upwards and a little backwards. 
The basis of the coronoid is extended anteroposteriorly. The distance from 
its anterior edge to the posterior border of the ranms is equal to the length 
from the former point to the anterior edge of the third incisor. The ante- 
rior edge is thickened inferiorly and extends downwards to below the alve- 
olar border, and externally to it, and graduates into the surrounding surface. 
The summit of the coronoid is obtuse. Its posterior border descends to 
near the condyle, and its superior half is bevelled from an angle of its inner 
face. The alveolar ridge extends within the base of the coronoid to a point 
below its apex, and then sinks. Below it the inner face of the ramus is 
concave continuously with the internal pterygoid fossa. The edge of the 
angular curve is bevelled on the external side. The angle separating the 
external face from the bevel is continuous with the posterior margin below 
the condyle, while the bevelled portion projects beyond it in an angle, half 
way between the condyle and the inferior border. The latter is not in tiie 
least incurved. 

The crowns of the first incisors in their present condition display no 
enamel, and the grinding surface of each is a rather wide oval with the long 
axis anteroposterior. The second incisor has the usual shoulder or ledge 
behind the scalpriform portion, as though it could he used for grinding as 


well as for cutting purposes. From this ledge the anteroposterior diameter 

is equal throughout. The exposed dentinal pcti-tion is more concave on 

one side than the other, though both are slightly concave. The enamel is 

strongly convex all round, excepting a shallow longitudinal groove on the 

more concave side. Its surface is marked with obsolete parallel ridges. The 

third incisor is a large prismatic tooth of triangular section. The inner 

face, which is applied to the second incisor, is flat, and is the widest. The 

anterior is convex, and is the next in width. The posterior external is a 

little narrower, and is flat. Its enamel has some obsolete longitudinal ridges, 

and several transverse undulations or obsolete ribs. The external face of 

the canine is narrower than that of the third incisor, and is wider than the 

posterior face. Anteriorly there is a faint longitudinal groove and several 

transverse undulations. The posterior face has transverse wrinkles. 

The grinding surfaces of the molars are subquadrate in outline, with 

rounded angles. The posterior three are rather narrower posteriorly than 

anteriorly. They are of about equal size, the first only being a little 

smaller than the others. The roots are conic in this adult specimen. The 

enamel extends well down on the external faces, although concealed in the 

alveolus. This looks as though the tooth enjoyed a considerable period of 

growth before the dentigerous pulp disappeared and the apex of the root 

closed. This is probably true in a more marked degree of the C. cylindri- 

fer. In wearing, the anterior external border of the crown is a little more 

elevated than the i-emainder. 



Length of ramus from coudyle to I. ii iucliisive 206 

Length of ramus from condyle to front of base of coronoid process 100 

Length of dental line l:!0 

Length of molar series 080 

„. , .. ,, ..< anteroposterior 0145 

Diameters ot M. ii < *^ 

( transverse 0145 

Diameters of canine ^ ° 

( shorter Oil 

„. . ,. T ..< anteroposterior 021 

Diameters ot 1. iii < ' 

( tr.insverse 010 

T^. . , I c T ••• (transverse 017 

Diameters external face 1. iii < 

( vertical from alveolus 020 



„. . T •• / 4. -i \ ( anteroposterior 
Diameters I. u (extremity) ^ ' 

. ( anteriorly 016 

transverse ■; ■' 

I posteruuly 010 

Depth of ramus at condyle 0d3 

Depth of ramus at apex of coronoid 115 


A young specimen apparently of this species is represented by the 
crowns of four mohxr teefli and by a canine. All are unworn and display 
the character of the unmodified grinding surfaces. The external and in- 
ternal enamelled faces of the canine approach each other at the apex, as in 
Edoganns, and are separated by a well-marked notch. The crowns of the 
molars are a good deal like those of Psittacotherium. They support two 
transverse crests which are separated by a deep open valley. The posterior 
crest is the shorter, and in most of the molars is divided into three tuber- 
cles, of which the median is the smallest. The anterior crest is divided by 
a deep fissure into two tubercles, each of which has a subacute transverse 
edge. Enamel smooth. From the Big Horn. J. L. Wortman. 

Calamodon cylindeifek Cope. 

Bulletin U. S. Geol. Surv. Terr.s. F. V. Hayden, 1881, p. 184. 
Pl.ite XXIV a ; ligs. IjVK!. 

The only individual of this species discovered by Mr. Wortman is 
represented by fragments of the jaws, with several teeth, both loose and 
imbedded in matrix. The former show that the molars have but one root. 
The latter include the large rodent-like incisors in a fragmentary condition, 
and a nearly complete tooth . intermediate in character between the flat 
banded teeth and the molar teeth of the known species of Calamodon. It may 
occupy an intermediate position in the jaw, but I do not know of any appro- 
priate place for it in the mandible of Calamodon arcamcenus. I think there is 
little doubt the individual belongs to a species with narrower teeth than 
any of those of the two species already named. 

The chiiracteristic tooth in question is nearly cylindric, and the part 
preserved is quite long and slender. Its grinding surface is worn con- 
cavely, as in the flat teeth of the known species of Calamodon. The enamel 
is in two bands, one wider than the otlier, nnd each of equal width through- 
out. The space of cementum separating them on one side is nearly twice 
as wide as that on the other. The cementum layer is not so thick as in the 
species of the genus hitherto described. The shaft of the tooth is sliglitly 
curvied, and tlie wider band of cementum is on tlic inner side of the curve. 




Width of enamel of large incisor 018 

Length of shaft of cylindric tooth 041 

Diameters of grinding surface of cylindric tooth \ anteroposterior Oil 

(transverse 010 


American Naturalist, July (June), 1882. 

Established on a tooth whose position is on the arc of the alveolar 
line which connects the molar and middle incisor regions. It is probably 
either the third incisor of the superior or inferior series, or canine of the 
inferior series. In either case it differs from the corresponding tooth of any 
of the known genera of Tillodonta or Tceniodonta. The long diameter of 
the root being placed anteroposteriorly, that of the crown makes with it an 
angle of 30°. 

Section of crown oval; the grinding surface scalpriform in the manner 
of a rodent incisor; but bevelled on one side of the long diameter instead 
of on the end, as in that order. Enamel consisting of a wide band on the 
external side of the tooth, which embraces more of the circumference near 
the apex than elsewhere. Apex grooved behind. 

If this be an inferior canine tooth it differs from that of the Tillodonta 
in its large size and incisor-like form. It most resembles the external or 
third inferior incisor of Calamodon. From this it differs in the scalpriform 
wear, and the oval instead of triangular section, and in the absence of 
cementum layer. 


American Naturalist, 1882, July (June). 

Plate XXIII d ; tig. 7. 

The enamel band does not cover the entire width of the external face, 

but leaves a part of the dentinal surface anterior and posterior to it, except 

at the apex. At the latter point there are seven coarse shallow grooves of 

the enamel surface; and the posterior of these split up below, and become 

narrower, while the anterior run out at the more oblique anterior edge of 

the enamel band. The posterior apical groove has a flat bottom. At the 

front of the apex the enamel is involute to the inner side for a short dis- 


tance. The inner face of the tooth disphxys five facet-like bands of the 
dentinal surface which soon disappear inferiorly. 



LfDKtli of tooth (root restored) 05t; 

Lt-ngtli (if eiiauiel baml .031 

Width of eaninel band at middle 0095 

DUmeters of middle of tooth ^''"'*^'"°P°«t«"°'" "130 

c transverse 009 

Long diameter of appx of tooth 008 

This tooth indicates a new and interesting type, perhaps, of Calamodon- 
tidce, and one of which moi'e information will be awaited with interest. 
Judging from the size of the tooth its possessor was as large as a sheep. 
From the Puerco Eocene of New Mexico; from D. Baldwin. 


There are three allied groups represented by the genera EstJionyx, Til- 
lotherinm, and Calamodon of the American Eocenes, which are equally unlike 
each other. Esthonyx, as I long since showed, is related to the existing 
Erinaceus; very nearly, indeed, if the dentition alone be considered. Its 
anterior incisor teeth are usually developed and have, as in Erinaceus, long 
roots. One pair at least in the lower jaw has enamel on the external face 
only, and enjoys a considerable period of growth. The genus Tillothermm 
is (tide Marsh) quite near to Esthonyx. Its molars and premolars are iden- 
tical in character with those of that genus, the only important difference 
being found in the incisors. Here, one pair above and one pair below are 
faced with enamel in front only, and grow from persistent pulps as in the 
Rodentia. This character has been included by Marsh in those he ascribes 
to his "order" of Tillodontia, but as he includes Esthonyx in that order,* which 
does not possess the charactei-, it is not very clear on what the supposed 
order reposes. The rodent character of the incisors is the only one I know 
of which distinguishes Tillotherium from the Insectivora. I have on this 
account retained the Tillodonta as a suborder, and referred Esthonyx to the 

There are three genera of this suborder: Psittacotherinm Cope, Anchij)- 
podus Leidy, and Tillotherium Marsh. The last one I only know from the 

* Report of U. 8. Geol. Stirv. 40t.h parallel, by Clarence King, vol. i, page 377. 


descriptions and figures of its describer. There are three species as- 
cribed to Tillotherium, while the other genera have two each. The genera 
are defined as follows: 

' First iuferior incisors present; six inferior molars with cross-crests . . Psittacotherium. 
First inferior incisors present; ?six inferior molars; trne molars with 

V's Anchippodus. 

First inferior incisors wanting; seven inferior molars; true molars 

with V's Tillotherium. 

The first-named genus approaches most nearly to Calamodon in the 
structure of the crowns of the molar teeth, and in the shortness of its den- 
tal series. It is only known from the Puerco formation. The two remain- 
ing genera have been found in the beds of the Bridger epoch. Tillotherium 
is nearest to Esthonyx, while Anchippodus is between the former and Psitta- 


American Naturalist, 1882, Feb., p. 156 (Jan. 25). 

This genus differs widely from the two genera hitherto known, Anchip- 
podus and Tillotherium. Owing to the absence of the superior dental series it 
is not possible to be sure which tooth is the canine. The inferior dental for- 
mula may be therefore written: I. 2; C. 1; Pm. 3; M. 3; or I. 3; CO; 
Pm. 3; M. 3; or I. 3 ; C. 1; Pm. 2; M. 3. The first and second incisors 
iire large and rodent-like, growing from persistent pulps; the second are the 
larger. The third, or canines, are small and probably not gliriform. There 
is no diastema. The first premolar (or canine) has a compressed crown 
with two cusps placed transverely to the jaw axis, and has a comjilete 
enamel sheath, and probably two roots. The succeeding tooth is also trans- 
verse, and is two-rooted, judging from the alveolus. The first and second 
true molars are rooted, and the crown consists of two transverse separated 
crests, each partially divided into two tubercles. On wearing, the grinding 
surface of each assumes the form of a letter B with the convexities ante- 
rior The last iuferior molar is injured. The rami are short, and the sym- 
physis deep and recurved. 

Two species are known, a larger and a smaller. In both the incisor teeth 
are very powerful, and the symphysis of the lower jaw is very deep, for 
their accommodation. They may have been adapted for breaking nuts and 
.seeds, as well as cutting roots. 



American Naturalist. 1862, p. 157 (Feb.)- 
Plate XXIV c, fig. 2. 

This animal is represented by an almost entire mandible, whicli indi- 
CJites an animal of about the size of the capybara {Hydrochoerus captjhara). 
The specimen has been subjected to pressure which has pi'essed the sym- 
physis backwards, and given it an angle with the ramus rather steeper than 
the normal one. 

The base of the coronoid process is opposite the junction of the second 
and tliird true molars. The ramus is deep and moderately stout. The 
enamel of the first incisor does not extend below the alveolar border, at the 
internal and external faces, and does not reach it at the sides. It has a few 
wrinkles on the anterior face. The anterior enan:>el 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. 


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^ 


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. 


No. 1. 


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. 


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 


of Didy'mictis, and throu<rli them to tlie tubercular ^^ectorials of the Oxycc- 
nidce, with which they agree in essential composition. 

On the other hand, resemblances between the dentition of Esthont/x, 
and the supposed Lemurine genus Pehjcodus are not wanting, and the 
rodent-like anterior teeth of the Lemuroid Chiromys suggest still further 
affinities between the Eocene members of that group and the Tilloclonta. 

There are two genera of this group known to me from the American 

Eocenes, whicli differ as follows: 

Anterior lobe of fourth inferior premolar a cone ; two inferior incisors Conorijctes. 

Anterior lobe of fourth inferior jjremolar with a concave edge; three infe- 
rior incisors Esthomjx. 

As the scaphoid and the lunar bones are separate in Esthonyx, that 

genus cannot be placed in the Erinaceidce. 


Paleoutological Bulletin No. 33, p. 486, Sept. 30, 1881; Proceedings Amer. Philos. See. 1881, p. 466. 

Dental formula, I.-; C. ; I'-ui. ' ''; M. '. Incisors small; canines 
1 \ 4 o 

large, with conic crowns. First two superior and inferior premolars with 

conic crowns; first inferior one-rooted, the second two-rooted, the fourth 

with an anterior conic cusp and a posterior grinding heel. Superior true 

molars transverse, with two external cusps. The inferior consist of two 

lobes, of subcylindric section, separated by deep vertical grooves. Enamel 

developed on internal and external faces of crowns 


Loc. Slip. cit. 
Plate XXIII (1, fiKS. 1-.^; XXV c, tigs. .3-4. 

Founded on a laandiljular ramus which lacks the last molar, and has 
the crowns of the others worn. The external faces of the molars are much 
more exposed than the internal, and are somewhat contracted upwards. In 
the unworn crown there is a distinct anterior inner cusp, which is soon con- 
founded on attrition. The heel of the last premolar has a crescentic section, 
the internal horn the narrower. The anterior lobe is a robust cone. The 
base of the second and tliiiil pirmujar is oblique to the axis of the ramus 


outwards and forwards. First premolar small, filling the short space 
between the second and the canine No cingula; enamel obscurely 
plicate, ramus robust. Length of inferior molars minus the last .0-465; 
length of base of first true molar, .010; width of do. .009; elevation 
of crown do. .0055; length of base of fourth premolar .011; width of do. 
.008 ; elevation of crown of do. .0065. Anteroposterior diameter of base of 
crown of canine .010. Depth of ramus at first true molar .023; width of 
do. at do. .013. This genus differs from EstJionyx in the form of the fourth 
premolar. In the latter the anterior lobe is compressed and trenchant. The 
species is larger than any of that genus, and nearly equal to the Edoganus 

Since the preceding was written, I have received Yrom the same region 
a much more complete specimen. It includes the greater part of the den- 
tition of both jaws, with mandibles, parts of cranium, limbs, etc. 

The mandible shows that the first true molar is the largest tooth, and 
that the crowns diminish in size in both directions. The third premolar has 
a nearly regular conic crown, with an oblique anteroposterior diameter a 
little the longer. Each of the preceding premolars has a single root. The 
inferior canines are very robust, and their crowns are strongly recurved. 
The external incisor is of good proportions, while the interior incisors are 
only half as large. The ramus is robust, and the symphysis is coossified. 
The inferior border of the ramus is slightly convex, and then rises, to the 
angle, commencing below the last molar. The angle is I'ounded, and is 
quite prominent, the posterior border being strongly incurved below the 
condyle. The latter is situated in the plane of the grinding surfaces of the 
molars. Its articular surface presents equally superiorl}^ and posteriorly. 
The edge of the angle is incurved, and rises as a support to the internal 
extremity of the condyle. The corouoid process rises immediately in ad- 
vance of the condyle, and its base has a wide anteroposterior extent; apex 
lost. The masseteric fossa is deeply impressed, but has no distinct inferior 
boundary. The anterior border is prominent, forming a flattened front of 
the process, which is oblique, projecting forwards as well as outwards. The 
ridge extends to below the anterior lobe of the last molar. On the inner 
side of the angular region there are four ridges for the insertion of the 


internal pterygoid muscle, etc. The two inferior are sublongitudinal and 

The crown of the superior third premolar is a slightly trihedral cone, 
with a low cingulum on the inner side. The crowns of the last four molars 
are transverse, narrowing to the internal rounded border. The fourth pre- 
molar has two external conic tubercles, of which the posterior is the smaller, 
and no cingula. The true molars have a low, interrupted, external cingu- 
lum, and two external cusps. Of these the anterior is large, and behind it 
is a small cingular cusp. The surfaces of the crowns are too much worn 
to display the detailed structure. As in the mandibular series, the first true 
molar is the largest tooth, from which the proportions diminish in both 
directions. The crotvn of the tliird molav is not larger than that of the 
third premolar. The molar bone is robust at the base, but becomes rapidly 
attenuated and compressed. It has no postorbital angle. 

Measurements of jaws. 


Length of last five superior luolara 040 

Length of true molars O-ii 

T^• . „„ T> 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 <H)S.> 

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 


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. 


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. 


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. 


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 


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. 


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. 

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. 


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. 


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 

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^ 


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. 



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 


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, 


/ 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-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. 

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^ 



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. 




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. 


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 


_..,,, , < anlero-poHtcrinr 0097 

Diameters of Jaat buperior iiioliir ? _ _ q.o- 


No. 2. 


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. 


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, 


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 

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. 


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. 


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. 


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.. Pantofes<es. 

• Proceed. Acad. Phila. , 1876, p. 88. Report U. S. Geol. Surv. West of 100th Mer., iv, p. 80, 1877. 
t Annual Report U. S. Geol. Surv. Terrs, for 1872, 1873, pp. 546, 607. 


Last premolar with inner cusp; all the molars with basin- 
shaped heel behind ; second premolar one-rooted Tomitherium. 

Like Tvmitherium, but second i)rcniolar two-rooted Pelycodus. 

Last i)reniolars with inner cusp; all the molars with elevated 

cusps behind ; second premolar two-rooted Sarcolemttr. 

AA. The anterior inner cusp undivided on all the molars. 

Last molar with heel; last premolar with inner cusp; four pre- 
molars Hyopsodus. 

Last molar without heel. 

Premolars four, last large ; sectorial, without inner cusp Aphelucns. 

Three or two premolars ; last without inner cusp Anaptomorphua. 

U. Last molar with a lonfritudinal series of alternating cusps, including a heel. 

Tubercles of molars 1-2, alternating Adapis. 

Tubercles of molars 1-2, opposite Opistlwtomus. 


Proceed. Acad. Phila. 1872, p. 20 (charncterized). Report U. S. Geol. Surv. Terrs, i, p. 82, 1873. Cope, 
Eeport Expl. and Sun-. W. of lOOtli Mer., G. M. Wheeler, iv, pt. ii, p. 134, 1877. 

This genus is easily distinguished from its alhes by the absence of the 
fii'st inferior premolar, and probably of the superior first premolar also. 
The canine tooth of the lower jaw of the M. scoitianus and M. gracilis is 
very large, so that I suspect that when the dentition is fully known there 
will be found to be a deficiency in the number of the inferior incisors. The 
dentition is otherwise as in Sarcohmur, i. e., the last premolar with internal 
cusps, and two anterior internal cusps of the true molars. 

The three species are distinguished as follows : 

I. Heel of last inferior molar very short. 

Length of true molar series '".0077 M. npierianm. 

Length of true molar series "'.0172 Jf. gracilin. 

II. Heel of last inferior molar long. 

Length of true molar series ™.0135 M. scotiianus. 


Americau Naturalist, 1879, p. 908. 

Platr xxvn.iig. 8. 

Established on a portion of a nuuidibular ramus which contains the 
three true mola is in perfect preservation. As the number of premolar teeth 
is unknown, its reference to this genus is provisional only. The last true 
molar has the form of that of the M. gracilis. It is distinguished by its 
small size, since it is considerably less than the Hyopsodus vicarius {HJ 


minusculus), and by the equality in size of the molars. The heel of the third 
molar is very small, and the two cones of the inner side of the crowns of 
all the molars are acute. The external crescents are very well defined, the 
anterior sending a horn round the anterior extremity of the crown. The 
posterior is connected with the corresponding internal tubercle by a median 
conic posterior tubercle. Length of true molar series, .008 ; length of 
second molar, .0026 ; width of second molar. .0022 ; length of last true 
molar, .0025; width of last true molar, .0016; depth of ramus at second 
molar, .0043. Dedicated to my friend Mr. Francis Spier, of Princeton, N. 
J., who, in connection with Messrs. Scott and Osborne, has made impor- 
tant additions to our knowledge of the Eocene Vertebrata. 

Valley of the Big Horn River, Wyoming. J. L. Wortman. 


Limuotherium elegans Mr.rsb, Amer. Jouru. Sci. aud Arts, 1871, ii, p. 43, fide Leidy. 
Miero8)jops gracilifi Leidy, Proceed. Acad. Phila. l6~-2, p. HO. 

This, the largest species of the genus, left abundant remains in the beds 
of the Wind River, Wyoming. The specimens in my possession agree 
closely with the descriptions and figures given by Leidy. The cusps of 
the molars are well developed, and the angles bounding the heels are dis- 
tinct. The fifth lobe or heel of the last true molar is quite small, and is on 
the inner side of the median line. 



Length of five last molars on liases 0206 

Length of last two premolars on bases 0070 

_. ^ „ , <• ^ i, 1 (anteroposterior 0030 

Diameter of base of fourth premolar < ^ „,„„ 

( transverse 0030 

anteroposterior 0040 

Diameters of second true molar < ^ „,,.,- 

I transverse 00J5 

T,. ^ i. , i ^ , C anteroposterior 0050 

Diameters of last true molar < ^ „„„. 

( transverse 003o 

Depth of ramus at third premolar 0090 

Depth of ramus at third true molar 0100 


Bulletin U. S. Geological Survey Terrs., 1881, p. 188. 

Plate xxiv a, fig. 21!. 

A nearly entire left mandibular ramus is all that I have seen of this 
species. The crowns of the fourth and sixth molars furnish the only dental 
characters available, but the number and forms of the bases of the others 
are readily ascertainable. 


Tlie ramus of the jaw is more slender than in M. gracilis, and tlie last 
true molar has quite a ditierent form. Instead of being- shorter than in 
allied species, this tooth is rather longer, evidently in consequence of a 
well-developed heel. The fourth premolar has a strong inner tubercle, and 
no anterior cusp or cinguluni. Its heel has an elevated posterior border, 
inclosing a fossa with tlie principal cusps. No external or internal cingula. 
Third premolar with two roots. Alveolus of the second, large and appar- 
ently simple ; it is filled with matrix. Canine large, directed forwards, and 
occupying all the space between a short diastema and the symphysis. The 
latter extends posteriorly to below the anterior part of the third jiremolar. 
The ramus is compressed and maintains an equal depth to the end of the 
molar series. Its inferior border descends below the coronoid process, and 
is not incurved, but the external face is convex. The anterior masseteric 
ridge is well marked, descending to below the middle of the ramus. Mas- 
seteric fossa flat. Mental foramen below the third premolar. 



Length of the fragment of raniim 04.'55 

Length of dental series witlioiit incisors 0280 

antero-jioHterior 0040 

Diameters of canine < ^ „^„ 

{ transverse 00"^ 

Length of premolar series 0100 

Length of fonrtli premolar 0040 

Width of fourth premolar l>ehind 0(W 

Length of true molar series 0136 

Length of last true 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. 


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 


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 

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. 


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. 


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 


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. 



Length of entire dental scries (straight) 044 

Lcnglli of Hj-mphysis mandibali 020 

Depth of ramus at svcood molar 010 



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 

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, 


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. 


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. 


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- 

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- 

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 


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 


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. 



-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. 


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 


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. 


No. 1. 


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. 


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. 


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 


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: 



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 


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. 


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. 


Length of base of M. i ami M. iii 0070 

I anteroposterior 0040 

Diameters M. ni, transverse 0045 

( vertical 0020 




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 

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. 


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 


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. 



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. 


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. 


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. 


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- 


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. 

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. 


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 


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 


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. 



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. 



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. 


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. 


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. 


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. 


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. 


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. 


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 


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. 



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 


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. 


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. 



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. 

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 


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 



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. 

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 


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 


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 Simiid<B should be read in place of Lemuridcr. 


those of the present genus. Dr. Filhol's l)eautiful collection, made in the 
Phosphorite beds of Southeastern France, was, through his liberality, 
thrown open to me, and I used the opportunity to study the extinct lemurs. 
There is much resemblance between the inferior jaw, with its dentition, of 
the genus Necrolemur* and that of Anaptomorphus, but the two inferior 
premolars of his Necrolemur antiquus have but one root. This chai-acter 
constitutes a basis for its generic sepai'ation from the A. aemulus. 


Paleontological Bulletiu, No. 8, p. 1, Oct. 12, 1872. Proceed. Amer. Philos. Soc, 1872, p. 554. Annual 
Report U. S. Ofol. Surv. Terrs., 1872 (1873), p. 549. 

Plate XXV, tig. 10. 

This species was about the size of a marmoset, or of a red-squirrel. 
The teeth are all closely packed. Tlie alveolus supposed to be that of 
the canine, is round and a little larger than that of the external incisor. 
The anterior premolar has two roots; the anterior one much smaller than 
the posterior. Tlie second root of the last true molar is inserted in the 
lower part of the ascending ramus, so that the tooth was obliquely placed. 
The anterior cusps of the true molars preserved are a little higher than the 
posterior. There are no cingula, and the enamel is entirely smooth. There 
is a small mental foramen, which is below the anterior alveolus of the ante- 
rior premolar. 



T.injj'th of dental line '0140 

l.engtli of last molar 0030 

l.eni^tli of antepenult 0030 

Width of .inteponult 0020 

I.eiijjilli of tliree niiilar» preserved 0070 

From the Bridger beds of the upper valley of Green River. 
The mandibular ramus of the Necrolemur antiquus is longer and rela- 
tively less robust than that of the American animal, according to Filhol. 

•Recherches s. les Phosphorites du Quercy, 1877, p. 275, flg. 216. Annalesdes Sciences Natnrelles, 


Anaptomorphus homunculus Cope. 

Paleontological Bulletin, No. 34, p. 152, 1862. Proceed. Amer. Philos. Soc, 1881, p. 154 (1882). 

Plate XXIVe, fig. 1. 

Thi.s species wns founded on a cranium without lowei' jaw. It is dis- 
torted by pressure, but its form is normally nearly rovmd, when viewed 
from above or below. The extremity of the muzzle is broken away, but 
the alveolus of the external incisor indicates that it is short and not pro- 
longed as in Tarsius spectrum. The mandibular ramus, already described, 
proves the same thing. The orbits are large, but not so much so as in 
Tarsius spectrum; their long diameter equals the width of the jaws at the 
last superior molar teeth inclusive. The supra-orbital borders project a 
little above the level of the frontal bone, which is concave between their 
median and anterior parts. The cranium is wide at the postorbital region, 
in great contrast to its form in the Adapidce, resembling the Necrolemiir 
antiqmis Filh. in this respect. The postfrontal processes are wide at the 
basal portion, and flat. From their posterior border the temporal ridges 
take their origin. These converge posteriorly and probably unite near the 
lambdoidal suture, but this part of the skull is injured. The anterior lobes 
of the cerebral hemispheres are indicated externally by a low boss on each 
frontal bone. 

The paroccipital process is short and wide at the base, and it is directed 
downwards and forwards. The alisphenoid descends so as to form a strong 
wall on the anterior external side of the otic bulla. This is also the case 
in Tarsius spectrum., but in the extinct species the descending ala is more and has a thickened margin. On the latter the external pterygoid 
ala rests by smooth contact of its thickened superior edge. The ala is twice 
as prominent as the internal pterygoid ala. The posterior nareal opening 
is not Avide, and its antei'ior border is parallel with the posterior border of 
the last superior molar teeth. The palate is wide, and its dental borders 
form a regular arcade as in man, being quite different from the form usual 
in monkeys and lemurs, including Tarsius. Perhaps the form is most like 
that of Microrluinchus laniger. The proximal parts of the malar bone are 
prominent, and overhang the maxillary border, as in Tarsius. 


The foramina ovale and hichrymale are rather largo. There are two in- 
fraorbital canals, lying beside each other, and issuing by two foramina ex- 
terna. The external appearance justified this conclusion, but the lact was 
demonstrated when I accidently broke away the anterior border of one of 
the orbits. This displayed the two canals filled with matrix their entire 
length. The anterior foramen externum is anterior to and above the pos- 
terior, and both are above the first (third) premolar tooth. The lachrvmal 
foramen is above the space between that tooth and the canine. 

The crown of the canine tooth is a cone with a very oblique base, and 
a convex anterior face. The base rises behind, and the posterior face has 
on the median line a low angular edge. The internal cone of the third 
(first) premolar is not so prominent as that of the second, though large. 
The external cusps of both premolars rise directly from the external base. 
They are flattened cones, with anterior and posterior cutting edges. The 
crowns are a little contracted at the middle, so as to be narrower than the 
inner lobe of the tooth, which is narrower than the external portion. Both 
premolars have delicate anterior, posterior, and external cingula. The ex- 
ternal cusps of the true molars rise directly from the external base, and, 
like those of the premolars, have a regularly lenticular section. At the 
internal base of each one is a small intermediate tubercle, which is con- 
nected by an angular ridge with the single internal cusps. There are deli- 
cate anterior, posterior, and external cingula, but no internal. The poste- 
rior cingulum shows a trace of enlargement at its inner part, which is well 
marked on the second molar, but it is not as prominent as in many Creo- 
dont genera. The posterior external cusp of the last true molar is reduced 
in size. Taking the molars together, the first true molar is the largest, and 
they diminish in size both anteriorly and posteriorly. The third true molar 
is a little smaller than the first (third) premolar. Enamel smooth. 



Length of rraiiiiiiii to occipital prominence above paroccipital process, and minns premazillarr 

boiio f^2S0 

Total width at posterior border of orbit, below (i240 

LfMi;;tli of piiliitu from front of canine tooth , 0116 

Width of palate jind ]ir>niiltiniato molars 012.'> 

Length of suixTior molar wrics 001)5 

Length of superior true niolars 0060 


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 


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 


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. 


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 

II Transactions of the Zoological Society of London, vi, pi. -2, On (Poiamogale) Mythomys velox. 


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, 


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. 


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. &. 



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 


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. 



ti(l<r, and which differ, so far as known, from Oxyrpna in the absence of the 
preglenoid crest. I suspect tliat these forms. constitute a family by them- 
selve.s, and for the present, until our knowledge of them is fuller, I define 
it by this character. 

Fig. 10. 

Fig. 10.— Maudible of Oriiwna forcipala Cope. one-Iial f uatural size ; a from above, b from left siile. From 
Kupoit Expl. burv. W. 100th Mer., G. M. Wheeler, vol. iv, pt. ii. 

Shortly after the publication of my arrangement of the Credonta in 
1880,* I obtained a good deal of additional material, which cMiabled me to 
improve it in several respects. A number of genera have been added, and 
the characters which distinguish the Miachhc and Oxi/iruifhr have been more 
fullv brouofht out. The il//rtc«/fP. differ from all other families in having the 
foui'th superior premolar sectorial as in the true Carnirora, while the true 
molars are tubercular. In O.ijidud, the fourtli superior ])remolar di.splays 
no indication of .sectorial structure, the true molar assuming that char- 
acter. In Sti/p(il()j)hu.s and allies, the second superior true molar is more or 
less .sectorial, and the first true molar and even the fourth premolar iii some 
of the genera, develop something of the same character. But there is every 

* rroceeUiiigH AmiT. I'hilon. Soiifi.v, p. Tti. 


gradation between the triangular Didelphi/s-Mke and the sub-sectoi'ial Ptero- 
don-\\ke forms of the superior molars in this group of genera. 

The definitions of the families will then be as follows : 

I. Ankle-joint plane transversely, or nearly so. 

True molars above and below, tubercular; last superior not transverse .. Arctoei/owid«p. 

Superior true molars, tubercular ; last superior premolar sectorial ; first inferior " tuber- 
cular sectorial" MiacidcB. 

Superior molars triangular, last one transverse; inferior molars tubercular-sectorial, 
or with reduced anterior cusp ; no preglenoid crest Leptictidce. 

Last superior molar trenchant, transverse ; first superior true molar sectorial ; inferior 
true molars tubercular-sectorial ; a preglenoid crest Oxycenidce. 

Last superior molar longitudinal; inferior true molars without developed sectorial 
blade Amhlyctonidce. 

II. Ankle-joint tongued and grooved, or trochlear. 

Molar teeth in both jaws consisting of conic tubercles and heels; none sectorial; a 
preglenoid crest . Mesonychidce. 

I novp give the characters of the genera. All these are derived from 

examination of typical specimens. The opportunity of doing this I owe to 

the kindness of Messrs. Leidy, Gervais, Gaudry, Filhol, and Lemoine. 


a. Superior molars with two internal tubercles. 
Premolars, f ; the first inferior one-rooted; the last inferior well developed. 

Arctocyon Blv. 
Premolars |; first two below one-rooted; superior molars with two internal cusps. 

Achcenodon Cope. 
aa. Superior molars unknown. 
Premolars below, 4; the first two-rooted, the last true molar much reduced (fide Le- 
moine) - Hyodectes* Cope. 

Premolars below, 3; first two-rooted ; true molars normal Heteroboriis\ Cope. 

aaa. Superior molars with one internal tubercle. 
Premolars below, 4, without internal tubercles; first one-rooted ; superior molars with 
an internal V, and intermediate tubercles Mioclmmis Cope. 


I. Fourth inferior true molar like the true molars, or with three anterior cusps. 

/?. Third superior premolar with internal cusp; anterior cusp of inferior molars 
small, median. 

Third premolar with one external and one internal cusps Mesodecfes Cope. 

Third premolar with two external and one internal cusps Ictops Leidy. 

* Type Arctocyon gervaimi Lemoine, Oss. Fobs, des Envir. de Reims, 1878, p. 8. 
tType Arctocyon duelii Lemoine, loc. cit., p. 9. 

tThe genera referred here resemble considertibly tlie family Didelphidce. The species of LepUclU 
and Mesodectea have thus far only been found in the White River beds; see Part Second of this volume. 


/3/3. Third superior premolar without internal cusps; anterior cusps of inferior 
molars present. 

Cusps of superior molars marginal ; two siijjerior incisors . . . Lepticliis Leidy. 

Cusi)s of sufierior molars median in position; anterior cusps of inferior molars well 

developed ; anjrle of mandible not inflected Peratherium Aym. 

ftfifi. Anterior cusi)s of inferior molars wanting. 

Fourth inferior i>remolar 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. 

Inferior tubercular molars two, premolars four Miacis Cope. 

Inferior tubercular molars one, premolars lour Bidymictis Cope. 


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. 

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. 


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. 



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 









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 





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. 


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 



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 : 










Meson vchidae. 


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 <in 
this sul)ject, published in the London Geological Magazine for May and 
June, 1880, unites Didymictia with Palceonyctis. Having examined the tyjjcs 
of both genera, my conclusion, as expressed in the preceding pages, is a dif- 
ferent one. On the other hand, I have good reason for believing the species 
to which the name Synoplotherium was given, S. lanius, is really a sec(»nd 
species of Mesonyx, of larger size than the M. ohtmidevs, and otherwise 

* ProceediDgs Acad. Phila., 1875, |i. 21. t Folidie and Canidie, loo. cit., 1879, ji. 169-170. On 

the Extinct Cats of Amecica, American Naturaliitt, December, 18d0. 


different. It is likely that some of the species of the Bridger formation, to 
which Marsh has applied generic names, belong to the Creodonta, and may 
belong to some of the genera described by myself The fact that no generic 
definitions accompanied the publication of those names, renders their use 

ICTOPS Leidy. 

Extinct Mammalia of Dakota aud Nebraska, 1869, p. 352. Proceedings Philadelphia Academy, 1868, p. 


Dental formula (derived from I. bicuspis where unknown in I. dakoten- 

3 14 3. 

sis) I. -; C. -; Pm. -; M. -. Third superior premolar tooth with two ex- 
2 1 4 3 

ternal and an internal cusp ; fourth premolar like the true molar, with two 

external tubercles, an internal tubercle, and a posterior cingulum. Fourth 

inferior premolar with an internal and a well developed anterior tubercle ; 

the anterior tubercle of the true molars median in position, and much 

smaller than the internal tubercle. Heels of molars with elevated cusps. 

Orbit not closed posteriorly. Cronoid process of the mandible well 

developed. Inferior margin of mandible not inflected. 

The genus Ictops was determined by Leidy from a species, the /. dako- 

tensis Leidv, from the White River formation. The animals now mentioned 

are identical with it in generic characters, so far as they are ascertained. 

The I. dakotensis is established on a specimen which does not contain all 

the teeth, but the parts preserved indicate that those which are wanting are 

like the corresponding parts of Leptictis Leidy and Mesodectes Cope, with 

which the present species also agree. It is unexpected to identify a genus 

found in the White River horizon with one from the Wasatch Ictops 

agrees very closely with I)idelp)liys. Tlie fourth superior premolar has an 

internal cusp, which is wanting in Didelphi/s, and the infei-ior border of the 

mandible is not inflected. There are also but three superior incisors on 

each side. Under these circumstances I prefer to refer this genus to the 

Bunotheria rather than to the Marsupkdia, but whether its proper place is 

in the Creodont or Insectivorous subdivisions I cannot yet determine. 


IcTOPS Bicuspis Cope. 

Bulletin U. S. Geol. Snrr. Terrs., vi, 1881, p. 192. Stypolophug bicuspis Cope, American Naturalist, 1880, 

p. 746, October. 

Plate xxix a, figs^ 2-3. 

This species is represented by a skull with mandible, from which the 
occiput is broken away. From it I have developed the entire dentition of 
one side, and nearly all of that of the other. The skull is about the size 
of that of a mink, and has the form of that of a civet. 

The premaxillary bone is remarkably extended anteroposteriorly, 
opposite the nares. The muzzle is moderately elongate, and is contracted 
laterally. The orbits are not defined posteriorly. The anterior temporal 
ridges are very obscure, and early unite into a low sagittal crest. The 
zygoma is proportionately very slender. The glenoid cavity is quite wide, 
and the postglenoid process is well extended transversely. The infraor- 
bital foramen issues above the anterior border of the first true molar. 
There are short diastemata behind the posterior incisor, and behind the first 
and second premolars. The first premolar is situated close to the canine. 

The crowns of the canines are compressed and rather short, with the 
anterior edge subvertical, and the posterior oblique. The latter is also 
acute. Crowns of second and third superior premolars compressed, with a 
prominent cusp behind the principal one. First and second true molars 
with two distinct external cusps and a strong external basal cingulum. 
The posterior basal cingulum is strong, almost developing a posterior inter- 
nal cusp in the first and second. There are no external cingula on the 
third and fourth premolars, excepting a short one opposite the posterior 
cusp of the fourth Inferior first premolar one-rooted, third with a posterior 
heel, and fourth with strong anterior and especially posterior heels. Heels 
of true molars well developed, cuspidate, the external lobe having a cres- 
centic section, and separated from the internal by a small median tubercle. 
The latter is strongest on the last molar, giving the heel greater length. 
The anterior internal cusp of the crown is much larger on the fourth 
inferior premolar than on the true molars, where it is absolutely median in 

The mandibular ramus is slender, and the inferior border is gently 


convex, descending again to the angle. The condyle is not very wide, 
presents upwards, and is on a line one-third way above the molars in the 
line to the summit of the coronoid process. The coronoid process is both 
high and wide at the base, there being no emargination between it and the 
condyle. The masseteric fossa has a distinct border anteriorly, which rises 
nearly to the summit of the coronoid process, and turns posteriorly to its 
posterior margin. Below, it fades out to the general surface. The inferior 
border at the angle is not inflected. An inferior pterygoid fossa of the 
inner surface has a marked superior boundary extending horizontally a 
little below the tooth line. A lower ridge extends downwards and back- 
wards parallel with the inferiorly decurved border of the jaw. 



Length of skull to posttyrapanio region 054 

Length of skull to orbit 031 

Length of skull to end of molar series 032 

Length from I. 1 to canine 0065 

Length from canine to end of molars 0220 

Length of premolar series : 0148 

Elevation of crown of canine 0040 

Length of base of Pm. iii 0045 

_. ^ . ,^. i , (anteroposterior 0040 

Diameters ot penultimate molar < , „.,_ 

{ transverse UU4o 

Length of mandibular ramus from Pm. 1 to condyle 0425 

Elevation of coronoid process from inferior border 0200 

Width of coronoid process at condyle 01 10 

Length of inferior molars 0235 

Length of inferior true molars 0095 

Depth of ramus at second true molar 0070 

Depth of ramus at canine 0035 

This species is smaller than any of the known Stypolophi, and is about 
equal to the Ictops dakotensis. Besides the characters already mentioned, 
the two-lobed external wall of the superior fourth premolar will readily 
distinguish it from any of the species of the former genus. 



Bulletin U. S. Gcol. Snrv. Terrs., vi.p. I9i, Febniary 26, 1881. 
Plate XXV a, fig. 9. 

Established on a left niaiKlihular raniu.s, which supjjorts the last three 
inolar.s. This demonstrates the t'oi-mer existence of a species of larger size 
than any of the LeptktidcE hitherto known. The general form of the infe- 
rior true molars is a good deal like that of Stypolophus, but they may be 
distinguished by three characters in whic h they at the same time agree with 
the htops biatspis: First, the elevated border of the heel, with a strong 
external cusp and weaker posterior and internal elevations ; second, the 
small development of the anterior cusp ; third, the posterior production of 
the heel of the third true molar, giving an indication of the fifth lobe. The 
external anterior cusp of tlie third molar is elevated ; on the first molar it is 
less so, and the anterior cusp is small. The enamel is smooth, and there 
are no internal nor external cingula. The mandibular ramus is compressed 
and deep. 



liength of bases of three true molars 01C5 

anteroposterior 0055 


Diameters of first tTue molar/ . , , ■ V 

( transverse belinul 

anteroposterior 0060 

transverse 0050 

Depth of ramus at anterior root of last true molar 0095 

T^- .^ ^. . 1 , ( anter 

Diameters ol last tnio molar? , 

( transverse 0050 

The jaw fragment described indicates a skull about the size of that of 
the common opossum. 

PERATII KlilUiM Aymard. 

Berpctotherium Copt, Paleontological Bulletin No. 16, ji. 1, August, 1873. Annual Report U. 8. Geol- 
Surv. Terrs., F. V. Hayden, 1873 (1874), p. 465. 

9 1 '-i 1 

Dental formula: I. - ; C. ; Pm. ^ ; M. . Fourth su])cri(tr iPiviiiolar 

like the true molars, with two external cusjjs and an internal one; third pre- 
molar compressed, with one lobe. Inferior molars with heel supporting 
cusps at the angles, and the three cusps anteriorh-, of which the e.xterior is 
most elevated and the two inferior subcqual. fourth premolar with the 
anterior internal cusp WL'll developed; the other inferior premolars simple. 


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. 


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. 



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. 


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- 

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). 


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. 


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. 


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 

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. 



. , (of cusps 0070|^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 


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. 



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 in its vertical measurements. 


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. 


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 



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 


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. 



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. 


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 


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. 


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. 


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 


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 


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- 



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 


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. 


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- 

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 


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. 



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. 


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- 


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. 


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 


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. 



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, 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- 


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 


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. 


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 


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 


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 


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: 


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 


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. 


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 


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. 



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. 


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 


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. 



( 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. 


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 


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 


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 

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. 



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 



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 


kindness of Professor Gnyot of Princeton College, who placed at my 
disposal a specimen acqxiired by him for the beautiful museum under his 

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. 


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 


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. 


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 


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 


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 

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. 



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- 

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. 



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. 

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, and the basis of the canine tooth is 


unusually large. Mental foramina are below the anterior parts of the sec- 
ond and fourth premolars, respectively. Last inferior molar small. 



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. 


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. 


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, 


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. 


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. 

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. 




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. 


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. 


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. 


No. 1. 


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 


No. 2. 


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. 


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. 


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. 



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. 


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. 



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- 


cies of Gahcynns and Temuocyon, aiul has tlie anterior basal tubercle which 
is wanting' to that genus but present in Aclnrodon. 


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) 


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. 



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. 


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. 


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- 


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 


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 


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 

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- 


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 



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. 


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 .. 





















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. 


The specimen above noted as No. 2 presents a good many parts of the 
skeleton, from which I derive the following characters: 


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 


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 


Measurements of posterior limb. 


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 



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. 


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 


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 


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. 



• 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 



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<re with two intermediate tubercles and two external 
tubercles. Inferior molars tubercular, the third with a tifth lobe or heel. 

More or less of the dentition of nine species of this genus is known. 
The only one of which any part of the skeleton is known is the M. fi.rox. 
The typical species is the M. turgvlus. 

The bones of the Mioclcenus ferox enable me to refer the genus approxi- 
mately to its proper position in the systen). Although we do not possess 
the corresponding parts of the MioclcenKs tun/iilus, the type of the genus, 
it is probable, if not certain, tliat they agree in generic characters. The 
agreement in dentition extends to all the principal technical points, though 
the specific diflFerences are marked. 

The skeleton is that of a creodont. The peculiar involution of ths 
zygapophyses of the posterior vertebrae, is seen in Mesonyx and in some 
Artiodactyles. The unequal phlanges are comj^-essed claws, and the meta- 
podial bones have protuberant condyles. The astragalus has a simple head 
with convex surface, and the trochlea is a shallow open groove. 

The tubercular dentition refers this genus to the Arctocyonidce* With 
this famil}'- it is accordingly placed provisionally. It differs from the known 
fossil genera in the single tubercle of the internal part of the crown of the 
superior molars. 

The species M. hrachystomus and M. etsagicus of the Wasatch epoch 
have been removed from this genus. I have shown that the former is an 
Artiodactyle. Now, in technical points, the dentition of those species is 
identical with that of Pantolcsten Cope, as well as with Miodceniis. Although 
the skeleton of the type of Fantolestcs. P. lonykaudus of the Bridger Beds, 
is yet unknown, it is safe to suppose that it does not differ from that of the 

"For the dentition of this-faniily sceJLeiDuiiii', Auuales, Sci. Nat., 1878, July. 


M hrachjstomus. I therefore refer the two species first mentioned to Panfo- 
lesfes and place that genus in the Artiodactyle sub-order. 

The species of 3Iioclcenus can be only as yet compared in their dentition. 
The characters thus derived are the following: 

I. Second inferior true molar without auy cusp on the heel, but a low ridge. 
Last true molars much smaller than the others; length of inferior true mohirs, 

.018 M. turgidus. 

Last true molars not reduced ; second superior, .015 by .013 ; largest . . M.ferox. 

Last true molars not reduced ; length of true molars, .012, least M. minimus. 

II. Second inferior true molar with internal posterior cusp. 

Last inferior molar reduced; inferior premolars robust; length of true molars, 
.016 M. baUhcini. 

Last inferior molar not reduced; inferior true molars, .020; inferior premolars com- 
pressed conic; superior true molars, .026 M. snhtrigonits. 

III. Second inferior true molar unknown. 

Larger ; second superior molar, .012 by .010 M. corrugatus. 

Large; lower true molars, .023, last little reduced ; second superior, .Oil by .008. 

Small ; superior true molars about .018 ; second larger than first, which is much larger 

than fourth premolar M. biicculentus. 

Large; cusps of inferior molars obtuse; inferior pm. iii, .008, its heel short and 

small M. mandibularis. 


American Natnralist, 1^81, p. H30, Sept. 22; Paleontol. Bull. No. 3^, p. 489, Sept. 30, 1881 ; Proceed. Amer. 

Pbilos. Soc, 1881, p. 489. 
Pl.ate XXV e, figs. 19-20 ; LVII f, fi^s. 3-4. 

The remains of this species have been more frequently obtained than 
those of others of the g-enus, eight individuals being represented in my col- 
lection. The characters displayed by the typical specimen are as follows: 
There are no cingula on the second, third, or fourth premolars. The last 
two are wider than long, and the external face is a little flattened. The 
tubercles in the third and fourth are conic; the external has a small one at 
the anterior base and a rudiment at the posterior base, and there is a low 
one on the posterior side at the middle. The second true molar is wider 
than the first. The tubercles are all round in section. Besides those 
already mentioned, there is a rudiment of a posterior inner on the first, 
which is represented b}- a cingulum on the second. The latter has basal 
cingula all around except on the inner side ; the same are visible on the first 
true molar in a rudimental condition. Enamel nearly smooth. 

32(3 Tin: puerco fauna. 

The interior molars are ol robust proportions. Their sizes are, coni- 
mencin<j with the largest: Pni. iv; M. ii : ^l. i: ^f. iii. The last molar is only 
half as large as the j^enultimate. It has two anterior and an external lat- 
eral tubercle and a heel. On the penultimate molar there are two anterior 
tubercles with a trace of anterior inner; also a broad flat heel, with a low 
tubercle on the external side. The constitution of the first true molar is 
identical. The fourth premolar has a rudi mental heel, consisting of a low 
tubercle only. The principal cusp is conic, and is over the middle of the 
transverse diameter, and a little behind the middle of the anteroposterior 
diameter. No cingula. Enamel nearly smooth. 


Masillarv bone. 


Length of base of P-m. iv, M. i,au<l M. ii 0175 

Diameters l.aso P-m. iv 5 ii'it^oposterior 005o 

< transverse 0065 

Diameters l.ase >,. i ^■'""^'"I"'^""""'' ^"^ 

I transverse 0070 

Diameters base M. jj U"««oposterior 0000 

( transverse 0(195 


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- 


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. 


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 

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 ) . 

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. 



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. 



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. 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 


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. 


^, . . , „ 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 


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 

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 


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 


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- 


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 


-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. 


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 

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" tliat of the latter animal. It is a short, flat cone, with 
two faces presenting on the same side; the one, part of the concavity men- 
tioned, the other, flat and presenting away from it. This piece has a slight 
resemblance to the very peculiar head of the fibula in. the opossum, but is 
not like that oi Sarcopliilus ursinus. I, however, think it much more prob- 
ably the proximal extremity of a marsupial bone. 

A sujjposed cuneiform is subtransverse in position, and resembles in 
general those of Oxycena and Esthonyx. It has the two large transverse 
proximal facets, the anterior one-quarter wider than the posterior. The 
distal facet (trapeziotrapezoidal) is simple. The navicular is much like tliat 
of Oxycena forcipata, but is more robust. Its external tuberosity is flattened 
aiiteroposteriorly, and is produced proximally. The three distal facets are 
well marked, the median a little wider than the external, while the internal 
is subround, convex, and sublateral in position. The entocuneifonn is a flat 
bone, with cup-shaped facet for the navicular and narrow facet for the first 
inetatiirsus. This facet is transverse transversely and concave anteroposte- 
riorly. It shows (1) tliat tliere is a pollex; (2) that it is probably small; 
and (."')) that it was not opposable to the other digits, as is the case in the 
opossum ; (4) it does not show whether the pollex has an imguis or not. 

Measurements No. 2. 


Traiisverso width condyle of maiKlildc (^230 

.■\iitoroiiost<i-ior width i-oiidyh' of ni»iidihh> (.it middle) "103 

niilUHtrr, hr.idofo.mam./mJ"""""'""'^ """!" 

f antcropcxiterior (KKV* 

Diaimt.-n. cuneiform J '■'•'•"''"' '^^^ 

< anttTopoHterior 01 1* 


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 

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 



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 



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 


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. 


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<j 

Diameters of M. iii ^^"t*^°P''«t''"°'^ ^°!? 

< transverse uUi» 

Rather larger than the pine weasel, Mustela americana. 


American Naturalist, 1881, p. 831, Sept. 22, 1881. Paleontological Bulletin, No. 33, p. — . 

Plate LVIIf; fig. 7. 

The typical specimen of this species is represented by two fr-agments 
of the left mandibular ramus which were apparently found together, but 
which do not fit, owing to the loss of an intermediate fragment, and accu- 
mulation of hard ferruginous stone. That they belong to the same ramus 


is probable but not certain. I liave therefore not referred it to its position 
in the genus as determined by the second inferior molar tooth, although 
that tooth is preserved 

The second or third inferior premolar is a rather large tooth formed 
somewhat after the pattern of the corresponding one of the species of Hap- 
locotius. It is compressed, has an elevated confluent anterior lobe, a large 
median lobe, and a low, short heel. The posterior face of the median lobe 
is truncate, and is bounded by two edges, of which the internal is continuous 
with the inner edge of the heel. The latter has a weak median keel wiiich 
rises to a jjoint of the posterior margin. Surface smooth, no cingula. The 
second inferior true molar has a large, wide heel, whose external side sup- 
ports a large tubercle. The posterior border is raised, and the size continues 
round the inner side, supporting two small lobes, one posterior, the other 
internal. The anterior cusps are large and closely approximated, and there 
is a small anterior inner cusp. This is a little inside of the middle line and 
is connected with the external anterior cusp by a ledge. No cingula. 



Ltngtli of Pm. iii 0080 

Width Pm. iii .at middle of base 0038 

5 anteroposterior OOliO 

Diameter M. >>• 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. 


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. 



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. 

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. 


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. 


Diameters M. i < ' 

< trausverso... 


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. 


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. 


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 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. 


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. 


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 


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 



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. 


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. 



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. 


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. 




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. 


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. 


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. 



\ 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 



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<l Carnivora of tbo Eoccueof Wyoiuing, .\])ril 19, 1873, p. 1. t Synoplo- 
therium Cope. Pal. Bull. No. fi, p. 1, Aug. 20, lb7->. 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 

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, 


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 


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 


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, 


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 


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 


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 


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 

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, 


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 

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 


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 


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 


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. 



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 



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 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 of both dog's and liears. 
The very prominent ])ostglenoid ridge, and the narrow tympanic chamber 


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. 


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 


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 

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 


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 


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 


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- 


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 

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. 


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 



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. 


Length from summit of great trochanter 315- 

Width of head 077 

Anteroposterior diameter of head .... O'iZ 

Width at third trochanter.. 048 

24 C 


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 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 


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 

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 


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 


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. 


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. 



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. 



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. 


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. 



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. 




* * 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//)Ao<fo«, one which he Stated that thi' l)ones "form in- 

thiril natural size. Original, fmni Ktrport of ■, ^ . • v tt i a. ^ 

Capt. <;. M. wintier, E.X1.1. w.ui lodM.r., terlockmg scnes. He however states 
vol. iv. 1-T7. I^l^.^f ii^yj^j niagnum is supported by the lu- 

nar and not at all by the scaphoid," a state of things which does not belong 

' Oatcutogy of the Mammalia, |i. '-206 : fig. 'M. 

'Systematic Calnlnguu of the vertebrata of the Kocono of New Mexico, p. 24 (I'. S. Oeol. Survey 
W. of liX»th Mer.;. 'Anier. Soi. Arl». xi. p. U>7 ; pi. vi, fig. 2. 



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. 



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 


Fig. 10.— Left pos- Order III 

articulating i)roximally with calcaneuni only. 

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. 


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 Toxo<lon, Prncep<liiif;H Amer. Pbilosoph. Society, 1881, p. 402. 
'The cousidenible reneniblancc lii'twecii the drntition of Tozodon and ffj/rax mnit not be over- 



II. Proboscidea. 
There may be two sub-orders of this order, the Proboscidea and the 

Toxodontia. I do not know the carpus of 
Toxodon, but if it does not differ more from 
that of the elephants than the tarsus does, it 
is not entitled to subordinal distinction from 
the Proboscidea. The sub-order of Probos- 
cidea is defined as follows : 

A fibular articulation of the calcaneum ; uo post- 
glenoid process; no third trochanter of femur 


III. Amblypoda. 

The sub-orders of this order, as I pointed 
out in 1873, are two, defined as follows: 

Superior incisor teeth; no ali-sphenoid canal; a 

Fig. 18.-Po8terior foot of Coryphodon ^j^j^.^, t.oehanter of femur ranU,(lonia. 

(original). From Capt. G. M. Wheelers ._ ... ,.,.-, 

Report Snrv.w. of 100 Mer.,iv. Cue-third ^o Superior incisors, nor ah-sphenoid canal, nor 

natural size. third trochanter of femur Dinocerata. 

The difference between the Proboscidea and the Amblypoda consists 
chiefly in that the navicular of the latter is short- 
ened externally so as to permit the cuboid to artic- 
ulate with the astragalus. The cuboid has the same 
form in botli. The peculiar character of the navicu- 
lar gives the astragalus a different form. 


This order is called bv some authors the Un- 
gulata, but that name is also used in the larger sense 
in which it is here employed. This appears to be 
its legitimate application, as the name should, if pos- 
sible, be used for hoofed Mammalia in general, as its 
meaning implies. The two well-known sub-orders Fig. i9.^— Left pes of Eie- 

,1 /. n . »Aas indiciiS one-tenth natural 

are the following : fi^^ . ^^^^^ ^^^^^^ 

Astragalus truncate distally ; number of toes odd, the median the largest . Pemso</rtc<y/fl. 
Astragalus with a distal giuglymus ; number of toes even, the two median largest. 




Phijlof/oiif. — The serial arrangement of tlie bones of the carpus and 
tarsus seen in the Tajeojmfa, is probably tlie primitive one, and we may 
expect numerous accessions to the order on further exploration of the early 
Eocene epochs. The modification seen in the more modern orders of Ppm- 
;•"■•; sodactyla and ArtiodadyJn, may Iju regarded as a rotation to the 

inner side, of the Imnes of the second carpal low, on those of 
tliL' first. This rotation is probably nt-arly coincident with the 
loss of the i)ollex, as it throws the weight one digit outwards, 
that is on the third and fourth digits, rendering the first func- 
tionally useless to a foot constructed solely for sustaining a 
weight in motion. The alternation of the two rows of car- 
pals clearly gives greater strength to the foot than their serial 
arrangement, and this may probably account for the survival 
of the tyi>e 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><um labia- Toxcopodd RXid Aiiihli/poda ou the one hand, and the Diplarthra 
Ai'io'ut onf-'t"b'ir!i <^>'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 


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. 


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- 

These relations may be rendered clearer by the following diagram: 

Condylarthra, Platyarthra.* 

Hyracoidea. \ 

Pboboscidea. Amblypoda. 

Hyodonta.* Pantodonta. 
I Dinocerata. 


/ \ 

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. 


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. 


'Journal of the Acatlemy of Natural Sciences, Philadelphia. 


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 

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). 


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. ». 


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 : 

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 


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. 

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. 

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«. 


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. 



The geological distribution of the nine genera of these families is as 
follows : 

Anisonchus .. 

Protogonia . . 
Anacodon . . 
Diacodexis . . 

Men iscotherium 









American Naturalist, 1881, p. 337 (March); Catathlmus, Cope, American Naturalist, 1881, 829, Sept. 22. 
Proceeds. American Philosoph. Soc, 1881, p. 487. 

Dental formula: I. 



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. 


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 

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. 


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 


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 


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 


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 


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 : 


No. 1. 


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 



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 


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. 


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 


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. 


No. 1. 


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. 


Measurements of humerus. 

No. 1. 


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. 


Measuremenis of ulna and radius. 

No. 1. . 


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. 


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 


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. 


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 


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. 

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 



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 


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. 


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 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 


Periptychus carinidens Cope. 

American Naturalist, 1881, March, p. 337. Paleontologlcal BuUetiu No. 33, p. 484, Sept. 1881. 
Plate XXV n, fig. 16; XXIII <i, figs. 14-15; XXIV j, fig. 5. 

This species is, with my present knowledge, only distinguished from 
the P. rJiahdodon by its inferior size and its longer and narrower last infe- 
rerior molar. This difference is seen in both adults and young of corre- 
sponding ages, and chiefly in the true molar teeth. While the length of 
those of the lower jaw varies in the P. rhabdodon from 33 to 35 millimeters, 
in the P. carinidens it only reaches 29 millimeters, or with the posterior two 
premolars .'iO millimeters. The details of the adult dentition do not differ 
from those of the P. rhabdodon, except that the last inferior molar is nar- 
rowed and produced posteriorly. 

The permanent dentition of this species is represented on Plate XXIII (Z, 
figs. 14-15; and the milk dentition on Plate XXV a, fig. 16. As the species 
was established on the latter specimen, I give a description of it. 

The second and third milk molars support a principal median cusp, a 
broad heel, and a prominent anterior cingulum. The heel is more or less 
divided into tubercles; the anterior cingulum is on the inner side, and rep- 
resents the anterior cusp of a sectorial tooth. On the inner side of the 
principal cusp a cingulum rises, forming a flat internal tubercle. The heel 
of the second supports three tubercles, of which the external is the largest. 
The anterior cingulum supports a small cusp and then rises to the internal 
tubercle, which is compressed. The sides of all the cusps are marked with 
distinct, well-separated vertical ridges. Each extremity of the internal cusp 
is connected with the principal cusp by a ridge. The first true molar has 
few cusps. Those of the heel are scarcely distinct, and form a border 
which rises prominently into the flat internal tubercle, which forms a nar- 
row longitu-dinal blade. The anterior cingulum has no cusp, and does not 
rise into the inner tubercle. The principal cusp has a strong entering 
groove next the inner tubercle. 

In these deciduous teeth the compressed semisectorial character seen 
in the first inferior true molar of Haploconus is carried back to the second 
true molar. The sectorial character is increased by the heel-like cliaracter 
of the posterior front of both first and second true molars, which lacks the 


cusps characteristic of Pheiiacodcnitidoe and ungulate mammals. These teeth 
therefore resemble premolars rather than true molars. Before I was ac- 
quainted with Hajjloconus, I provi.sionally referred this genus to the Creodonta; 
the resemblance to Haploconus is, however, unmistakable. The ridging of 
the enamel is also present in the milk dentition. 

Measurements of milk dentition. 


Length of crown of first molar 0113 

Width of crown of tirst raolar 006 

Elevation of crown of first molar (XHi 

Length of secouil molar Oil 

AViilth if second molar 00" 

Elevation of second molar 0065 

Depth of ramus at second molar 020 

The species was obtained by Mr. D. Baldwin from "below all the 
Wasatch Sandstones," in the Puerco. 

Peeiptychus diteigonus Cope. 

Plate XXIII </; fig. 12. 

This rare species is known from a right mandibular ramus which exhibits 
part of the symphyseal suture, with the alveoli of the molar teeth except 
the first. The only well-preserved crown is that of the second ti-ue molar. 

The second true molar presents very peculiar characters, and the 
mandibular ramus is shallower and thicker than in the two other species of 
Peripfi/chus. The former has a wide external cingulum which is not present 
in the other species, and there are only six cusps instead of seven. These 
are peculiarly arranged. The anterior three are much as in P. rhabdodon, 
the anterior inner being not quite so far internal as the posterior inner, close 
to it and as large as the anterior external. The posterior three are a pos- 
terior inner and posterior median as in P. rhabdodon, and a peculiarly placed 
posterior external. This is not opposite the posterior inner, but is anterior 
to such a position, and intermediate between the latter point and the one 
occupied by the median tubercle in P. rhabdodon. It is as large as the an- 
terior external tubercle. All these tubercles are conical and not connected 
by angles or ridges. The position of the posterior external cusp leaves the 
cingulum wide posteriorly, and near its edge develops some small tubercles. 
There are also some small tubercles at other points on the edge of the crown, 
but no other cingula. The enamel is not regularly ridged as in P. rahbdodon, 
but has a rather coarse obsolete wrinkling-. 



Length from Pm. ii to M. ii inclusive- 052 

Diameters of M.ii 5 '*°t''''''P°«*'="°'' ^^ 

■< transverse 010 

Depth of ramus at M. ii 022 

Width of ramus at M. ii 016 

Depth of ramus at Pm. ii 019 

From the Puerco formation of New Mexico; D. Baldwin, discoverer. 

American Naturalist, 188-2, p. 832. (Sept. 28.) 

? 1 4 3 

Known from dentition only. Dental formula: I.^; C. -; P-m.-; M.- 

•^ V 1 4 3. 

Superior true molars with two external cusps and an internal V. No inter- 
mediate tubercles, nor internal tubercles or cusps, other than the apex of 
the V. Third and fourth premolars with one external and one internal cusp. 
Inferior true molars with two anterior and two posterior cusps, with some 
supplementary tubercles. First inferior premolar one-rooted ; second with 
two roots and a simple crown. Crowns of second and third unknown. 

This genus has the premolar teeth of the species of Anisonchus with 
the inner lobe conical. Its principal peculiai'ity consists in the absence of 
the posterior internal cusp, which is such a prominent feature in Anisonchus 
and Haploconus. 

Two species are known, both from the Puerco formation. 


American Naturalist, 1882, p. 832. (September 28.) 
Plate XXV /; figs. 6-7. 

This animal is represented in my collection by parts of the crania of 
two individuals. One of these includes a right maxillary bone with bases 
of six molars, and crowns of four, the last being absent; and a left mandi- 
bular ramus with bases of six molars, and crowns of four, the Nos. i, ii, v, 
and vi. The second specimen includes a right maxillary with the posterior 
four molars preserved, and the right ramus with the true molars i and ii 

In size this species yields to the Anisonchus coniferus and the Haplo- 
conus entoconus, but is larger than the A. sectorius. The third and fourth 


superior premolars are of about equal size, and larger than the true molars, 
but of much more simple construction. They have anterior and posterior 
cingula (weak on the third), but none on the external or internal bases. 
The bases of the superior true molars are wider than long, but are not so 
much extended inwards as in the Anisomhus coniferns. Their external 
cones have short acute apices with circular section. They are partly con- 
fluent at the base. The ridges which form the limbs of the V originate, 
one at the internal base of each, and unite at a more acute angle than in 
Auisonchiis sectorius or Haploconiis lineatus. There is an external ciugulura, 
weak on the last superior molar, and an anterior and a posterior one, but 
no internal one. The anterior and posterior cingula are equally developed, 
and they rise with a curve to the edge of the V, reaching it a little exterior 
to the apex. The last superior true molar is smaller than the others, but 
has similar proportions. 

The crown of the first inferior premolar is much smaller than that of 
the second, and has a lenticular section. That of the second is large and 
robust, and has a stout lenticular section. The first and second true molars 
have a small but distinct anterior median tubercle, and a rather larger me- 
dian posterior tubercle. The sections of the lateral posterior tubercles are 
lenticular. The anterior pair soon become confluent on wearing, as their 
bases are closer together than those of the posterior pair. No cingula. 

The enamel is smooth in all the specimens. 

In the second individual the malar bone is deep and flat on its external 
face, and a slight convexity of its superior border indicates the posterior 
edge of the orbit. The posterior edge of the last superior molar is opposite 
the middle of this enlargement, while the notch between the posterior border 
of the maxillaiy bone and the malar enters a little in advance of this point. 


No. 1. 


Lentil of iiiaxill.-iry Ixme posterior to canine, to M. iii exclusive . 033 

Lt'Djfth of liiiHe.s of nioKim ii, iii, iv, and v 020 

Dinmotow of Pm. iii ^ '"'•-'•"P"'"^"!"' ^2. 

( transvcrw 007 

Din.n..U-™ of Pm. i,. ^ '""•■'■"I"-Ht.Tior 005 

< traiisvfreo 007 

Luogeh of biiHcg of unterior six inferior molars 027 



Length of four premolars 017 

Length of base of crown of Pm. ii 0045 

Diameters of inferior M.ii^'"'*''^"?''***'"''' 0046 

c transverse 004 

No. 2. 

Length of superior true molars 013 

Diameters M. „ ^ anteroposterior 0045 

( transverse 007 

Diameters M. iu ^anteroposterior 004 

( transverse 006 

Diameters Pm. 1^5 anteroposterior 005 

( transverse 007 

This species was found by Mr. D. Baldwin in the lowest beds of the 

Puerco formation in Northwestern New Mexico. I dedicate it to Dr. 

Waldemar Kowalevsky of Moscow, one of the most able of the European 


Hemithl^eus opisthacus Cope. 

Proced. Amer. Philos. See. 1882, p. 467. Mioclaeiim opisthacus Cope, American Naturalist 1882, p. 833 

(September 20). 

Plate XXV f; figs. 8-9. 

This species is known from fragments of four mandibles, and a broken 
last superior molar tooth, found together by Mr. Baldwin. The mandibles 
belong to one species, and there is nothing to cast doubt on the reference 
of the superior tooth to the same. This tooth refers the species to the 
genus HemithlcBus. 

This species resembles its congener in the abrupt diminution in size of 
the premolars anterior to the third. The contrast between the second and 
third is greater than in the H. kowalevsJcianus. The anteroposterior extent of 
the former is little more than half that of the latter. The third and fourth 
premolars are large and oval in horizontal section, and quite similar in size 
and form. The heel of each is small, and has a median elevation, and that 
of the fourth is a little the larger. The fourth premolar is not larger than 
the first true molar. The true molars become narrower posteriorly, and the 
first is as large as or larger than the second. The anterior two cusps of thd 
molars are more elevated than the posterior; they soon unite on attrition. 
There is no interior median cusp, but a narrow ledge in front of the ante- 
rior cusps, on the second and third molars; the first is worn on all the 


specimens. The posterior two cusps are well developed, and soon connect 

on attrition, and the external sends a long point forwards and outwards. 

The third molar has an elongate heel, and internal and external median 

cusps, of wliich the latter is crescentic in section. The ramus is compressed, 

and becomes shallow anteriorly. 

The superior molar has the characters of those of H. kowalevskianuSy 

the external wall being lost. 


Lenpth of posterior six inferior molars (No. 1) 036 

Length of base of Pm. ii (No. 2) 003& 

T%- .. „ -D-, ■■■< anteroposterior (No. 1) 007 

Diameters Pm. iii ^ ' ,v \x nni 

< transverse (No. 1) w-i 

Diameters Pm. iv 5 anteroposterior (No. 3) 0008 

( transverse (No. 3) 0045 

Diameters M.ii^''°'«^°P°«»«':j°^(f°-^) °^ 

I transverse (No. 1) OOo 

T^. . ■., .-•< anteroposterior (No. 1) 00C6 

Di.imeters M. Ill ^ ' .»t ,n nm 

t transverse (No. 1) 0U4 

Depth of ramus at Pm. iii (No. 1) 008 

Depth of ramus at M. ii (No. 1) OU 

Besides the difference in the relations of the inferior premolars above 
cited, this species differs from the H. Jiowakvskianus in its superior size. 

The jaws described were found by Mr. D. Baldwin in the Puerco bed& 
on the Rio San Juan, New Mexico. 


Paleontological Bulletin, No. 33, p. 488, Sept. 30, 1881. Proceedings American Philosophical Society, 

1881, p. 488. 

This genus is only known from dental characters, and only the molar 

teeth have been preserved. These are Pm. -r-; M. -. The first superior 
'^ 4 3 

premolar is unknown. The third and fourth consist of an external conic 
cusp, and an internal elevated crest or lobe, as in Periptychus. Molars sup- 
porting two external tubercles, an internal V, and a posterior internal cusp 
cut off from the internal V. The limbs of the V represent the intermediate 
tubercles of Periptychus and other genera, and the apex of the V represents 
the internal median tubercle of that genus The posterior internal cusp 
is separated from it by a vertical groove on the inner face of the crown,, 
and is continuous with a posterior cingulum of the crown. 


The inferior premolars have no internal cusp or crest, but the P-m. iii and 
iv have a heel. The true molars have anterior and posterior intermediate 
tubercles. The last true molar has a heel. The premolars in both jaws are 

The difference between this genus and Periptyclms is well marked in 
the superior true molars ; the two genera are otherwise much alike. The 
inferior premolars of Anisonchus differ in the absence of the internal cusp. 

There are three ^ell-marked species of this genus, which differ as 

Internal lobes of superior premolars conical; width of base of second true molar, .010; 

large -I- coniferus. 

Internal lobes of third superior premolar conic; of fourth, flattened and concentric; 

width of M. ii, .007; length, .004; small A. gillianus. 

Internal lobes of the superior premolars flattened and continuous with ciugula; width 

of M. ii, .006; length, .0046; medium A. sectorius. 

The type, and first discovered species, is the A. sectorius, which is also 
the most abundantly represented in my collection. 

Anisonchus coniferus Cope. 

American Natural iat, 1882, p. — (Sept. 28). 
Plate XXIV 3; fig. 6. 

This is the largest species of the genus, and the largest of the Perip- 
tychickB after the species of Periptychus. My knowledge of it is based on 
fragments of two skulls which exhibit the superior molars following the 
P-m. i, and the crowns of the inferior P-m. ii, and M. ii and iii. A calca- 
neum of appropriate size accompanies the jaw-fragments. 

The second superior premolar is a robust tooth with a subtriangular 
base, and simple conical external cusp, and a small internal basal cusp. A 
trace of anterior, but no other cingulum. The third premolar is more 
robust, and probably has a larger internal cusp, but this is worn off by 
mastication. There are faint anterior and posterior ciugula not connected 
with this cusp; none externally or internally. The fourth superior pre- 
molar has a much greater transverse extent. Its external cusp is simple, 
and without accessories, while the internal is large and is connected by its 
edge with a well-marked anterior cingulum. A weak posterior cingulum; 
none external. Crown worn. The true molars are distinguished by their 


transverse extent. The accessory cusp, posterior in A. sectorius and in 
Haphconus Hneatus, is nearly median on the second and third true molars, 
though continuous witli the posterior cingulum. Median V shortened; 
external cusps conic. True molars with an external, as well as anterior 
and posterior, cingula. No internal cingulum. Enamel smooth. 

Fragments of the mandibles show tliat the masseteric foramen is not 
impressed anteriorly, but the anterior ascending coronoid ridge is strong. 
The first inferior premolar had a single robust root. The second is two- 
rooted. Its crown is robust; and lias a small transverse rudiment of a 
heel. The second true molar is rather abbreviated. It has two elevated 
cusps anteriorly, which are confluent at the base, and are supplemented by 
a small tubercle in the middle of their anterior base, between them. The 
posterior part of the crown supports three cusps, of which the internal and 
posterior are small, and the external is an angle from which a ridge extends 
anteriorly and inwards. The posterior inferior molar is longer, having a 
heel. The anterior cusps are confluent at the base, and there is a small 
Ijasal tubercle in front of the inner lobe. There is a narrow cingulum at 
the internal base of the internal anterior cusp, but at no other part of the 

The infraorbital foramen is above the middle of the second superior pre- 
molar. There is a mental foramen below the fii'st inferior premolai'. 


No. 1. 


LeugtU of bases from superior Pm. iii to M. ii, iuclusivo 023 

Diameters p,n. jji $ anteroposterior 0065 

c traiisverwi 0075 

Diameters p„,. iv^-'"ie'-"P"«t''"or ^>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 


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 

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 


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 

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 


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. 

No. 1. 


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 


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 



Lcngtb of three superior molars 0160 



Diameters superior M.i J ""tcroposterior 0052 

( transverse 0060 

Length of inferior molar series 0010 

Length of inferior true inohir series 0160 

terior 0060 


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 


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. 


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 


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 



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. 

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 


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, 


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. 

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 


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. 



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- 


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 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. 


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. 


No. 1 {superior molars). 


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$). 


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). 


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. 



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, 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 


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. 



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. 


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. 


No. 1. M. 

Length of base:) of three superior molars 025 

_. ^ , . _ . (