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DEPARTMENT OF THE INTERIOR.

R K P» ( ) R T

CSITED STATES GEOLOGICAL SURVEY

THE TERRITORIES.

F. V. H-AYDEN,

UNITED STATES GEOLOGIST-IN-CHAUGE.

IN FIVE VOLUMES.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.
1873.

LETTER TO THE SECRETARY.

Sir: 1 have the honor to jircsent for your approval and for publication the
tirst part of volume I of the quarto series of reports which are intended to
embody the more original and technical results of the survey under my direc-
tion. Tlie present memoir on the " Extinct vertebrata of our Western Terri-
tories" has Ijeen elaborated by Professor Joseph Leidy, the eminent compar-
ative anatomist, and will form one of the most important contributions to the
science of extinct organisms ever made in this country. This memoir will
be followed b}' a second part on the same subject by Professor E. D. Cope.

Volume II will embrace the subject of the extinct flora of our western
Territories ; and it is the purpose to make it as exhaustive as possible. Pro-
fessor J. S. Newl)erry is preparing the first part and Professor Leo Lesque-
reux the second. The well-known reputation of these gentlemen is a suffi-
cient guarantee for the value of their work.

Volume III will include all the materials collected by the survey ou the
subject of extinct invertebrata, and will be most carefully elaborated by the
eminent j)aleontologist of the survey, Mr. F. B. Meek.

Volume IV will embrace the profiles, sections, maps, and other illustrations,
with descriptive text by the geologist in charge.

Volume V will contain separate memoirs on different subjects in recent
zoology and botany, prepared by several authors. All the new and imper-
fectly described species of plants or animals collected by the survey will be
studied and fully illustrated. All these volumes are now in an advanced state
of preparation. In presenting to the world these important contributions to
science, permit me, sir, to extend to you my sincere thanks for your intelH-
gent sym]iathy and hearty co-operation in the work.
Very respectfully, your obedient servant,

F. V. HAYDEN,
United States Geoloff,ht.

Hon. C. Delano, Scrrctarji of the Ii/fcrior.

"V^OLXJME I.

FOSSIL VERTEBRATES

P^RT 1

CONTRIBUTIONS

EXTINCT VERTEBRATE EAUNA

THE WESTERN TERRITORIES.

liV

PROF. JOSEPH LEIDY.

TABLE OF CONTENTS.

Pafie.

PREFACE 14

EXTINCT VERTEBRATE FAUNA OF THE BRIDGER TERTIARY FORMATION OF WYOM-
ING TERRITORY 15

INTRODUCTION 15

MAMMALIA 27

Oider PcrissodactyJa 27

PalsBosyops - 27

paludosua 28

major 45

Junius 57

Lininoliy us 57

Hyrachy us 51(

agrarius (iO

exiaiius OG

modestus 07

nanus fi7

Lopliiotberium <i'J

sylvaticum : G9

Trogosus • 71

castorifleus 71

vetulus 75

Hyopsodas 75

paulus 75

niinuscnlus 81

Microsus HI

cnspidatus 81

Myciosy ops 82

gracilis 83

Nothaictus 86

tenebrosus 86

Hipposy us 90

formosus 90

robustior 93

Order Prohoscidea 93

Uintatberium 93

robustum 96

Order iJo(?(;H(ia 109

Paraniys 109

delicatus -. 110

delieatior 110

delicatissimus Ill

Mysops I'l

minimus Ill

fraternus 11-

Soiuravus 113

Order Carnirora Ill

Patrioft-lis 114

ulta 114

Sinopa : 11<5

ra]ias 116

eximia ■■ 1^^

;/;^

H CONTENTS.

MAMMALIA— Coutiniu'd.

Order Carinvora. Page.

Uiutaoyon 118

eclax 118

voras V.>0

Order Iiiscct'ivora • \->Q

Oiiiomys '. li>0

Carter! 120

Palaaacodon 122

veriTs 122

Wasbakius ■ 123

iusiguis 123

Elotboriiiiii 124

EEPTILIA 125

Order CrocodiUa 125

Crocodilus ' 125

aptus 126

Elliotti 12G

Order Chi-lonia .• 132

Testudo 132

Corsoni '. 132

Emys 140

•vvyomingensis 140

Bapteniys 154

wyoraingensis 157

Baena 160

arenoaa ' Kil

Cbisteruoii 169

undatam 1G9

Hybemys 174

arenariiia 174

Auosteira 174

oruata 174

Trionyx 176

guttatus 176

uintaeusis 178

Remains of Trionyx of undetermined species 180

Order LaccrllUa 180

Sani wa 181

ensidens 181

major 182

Gly ptosaurus 182

Cbameleo 184

pristinus - 184

FISHES 184

Amia (Protamia) uiutaensis 185

media 188

gracilis 188

Hypaniia 189

elegans 189

Lepidosteus 189

atrox 189

(?) 190

simplex 191

notabilis 192

Pimelodus 193

antiquus - 193

Pbareodus 193

acutus 193

CONTENTS. *J

FISHES— ContiiiMcil. Page.

REMAINS OF FISHES FROM THE SHALES OF GREEN RIVER, WYOMING m

C'lnpea 195

huiuilis 195

alta 1%

DESCRIPTION OF REMAINS OF MAMMALS FROM THE TERTIARY FORMATION OF

SWEETWATER RIVER, Vv'YOMING 198

MAMMALIA 199

Order Itumhiaiitia 199

Jleiycoehcerus 199

rusticus 199

sp. (?) 208

Order Sorulmujii!" ■■■■ 208

DESCRIPTION OF VERTEBRATE FOSSILS FEOxM THE TERTIARY FORMATION OF

JOHN DAY'S RIVER, OREGON 210

MAMMALIA 211

Order liiiminaiitia 211

Oreodon 211

Culbertsoui 211

superbus 211

Leptomeryx 21(j

E vansi 210

AgriocbcBrus 216

autiqiius 210

latifrous , 216

Order Ariiodactijla _ 210

Dicotyles 216

pristiuus 216

Elotberium 217

imperator 217

Order Solidungula „ 218

Ancbitherium 218

Bairdi 218

Condoui 218

Order Pcrissodactyla 219

Lopbiodou 219

Rhinoceros 220

besperius 220

pacificus 221

Hadrobyiis 222

supremus 222

An luidetermiued carnivore 223

CHELONIA 223

Styletiiys 223

uebrascensis 224

niobrarensis 225

oregouensis ' 226

DESCRIPTION OF REMAINS OF VERTEBRATA FROM TERTIARY FORMATIONS OF

DIFFERENT STATES AND TERRITORIES WEST OF THE MISSISSIPPI RIVER 227

MAMMALIA 227

Order Carnivora 227

Felis 227

augustus 227

imperialis 228

Canis 230

indianeusis 2:;0

Order Proboscidea 231

Mastodon 231

obscurus 231

mirificus 237

iimericanus 237

II — U

10 CONTENTS.

MAMMALIA— Coutinuoil.

Order Prohoscidca. Pa^o.

Elephas 03^

americauus o^^

Megacerops 239

coloradensis 239

Order SoUdungula 242

Equus 242

occidentalia 242

major 244

Hippariou 247

Prof ohiiipus s. Merychippus 248

Auchitherium 250

australe 250

agreste 251

(?) 252

Order Ruminantia 253

Bisou 253

latifrous _. 253

AucUenia 255

hesterna 255

Procamelus 258

virginiensis 259

Megalomerys 2()0

niobrarensis 230

CHELONIA 260

Emys 260

petrolei 260

FISHES 201

Family Ci/prinida; 262

Mylocyprinus 262

robustus 262

Family Eaice 264

Oncobatis 264

pentagouus 264

DESCRIPTION OF REMAINS OF REPTILES AND FISHES FROM THE CRETACEOUS

FORMATION OF THE INTERIOR OF THE UNITED STATES 266

REPTILES 267

Order Dinonaurla 267

PoicilopleuroQ 267

valena 267

Order Chdonia 269

Order Mosusauria 270

Tylosaurus 271

dyspelor 271

proriger 271

Lcstosaurns 276

coryphiBus 276

Mosasaurua 279

Clidastes 281

iutermedius 281

affiuis 283

Order Lacertilia 285

Tylostens 285

ornat ns 285

Order Sauroj)tcrijfjia 286

Oligosimus 286

graudajvus 286

Nothosaurus 287

occiduna 287

FISHES 288

Teleostei 288

CONTENTS. ] 1^

FISHES— Continued. Pago

Order Acanthoptai 288

Spliyrajnidao 288

Cladocyclus 288

occidentalis 288

Enchodns 289

Shuniardi 289

Phasganodus 289

dirns : 289

Older Malacopteri 291

Silurida) 991

XiiJhaotinus : 291

audax . 291

Ganoidei 292

Pycuodus 292

faba 292

Hadrodus 294

prisons 295

Elasiiobi:axciiii 295

Order Plagiostomi 295

Ptychodus Mortoui 295

occidentalis 298

Whippleyi 300

Acrodns :500

humilis 300

Galeocerdo 301

falcatns 301

Oxyrhina 302

extenta 302

Lamna s. Oxy rbiua 303

Otodus 305

divaricatus 305

Order Holocephali 306

.Edaphodon 306

mirificus 306

Eumylodus 309

laqneatns 309

NOTICE OF SOME REMAINS OF FISHES FROM THE CARBONIFEROUS FORMATION OF

KANSAS 311

Order Plagiostomi 31]

Cladodus 311

occidentalis 311

Xystracanthus 312

arcuatns 312

Pctalodus 312

alleghauiensis 312

Asteracanthus . 313

siderius 313

SYNOPSIS OF THE EXTINCT VERTEBRATA DESCRIBED OR NOTICED IN THE PRESENT

WORK : 315

Philadelphia, January 13, 1873.
Dear Sir: Herewith I transmit to you my report on vertebrate fossils from
the Western Territories and States. Many of the specimens were collected
during your geological explorations, and were submitted to me for investiga-
tion. Others have been collected by different persons living in the West,
and sent to me directly, or through the agency of the Smithsonian Institution,
for examination. Most of the fossils were obtained in Wyoming, and the
others were derived from Oregon, California, New Mexico, Idaho, Colorado,
Kansas, and Nebraska.

With respect, I remain, at your service,

JOSEPH LEIDY.
Professor F. V. Hayden,

United States Geologist.-

2 G

PREFACE.

The present work was commenced in 1870, at which time the amonnt of
materials as subjects of investigation and description was comparatively small.
A constant accession of new materials, beyond all anticipation, has greatly
extended the work. This will account for the apparent want of system in
the arrangement or proper collocation of the subjects of many of the plates.

The interest excited by the numerous discoveries of vertebrate fossils in
the Western States and Territories has led to the recent explorations of Pro-
fessors Marsh and Cope, both of whom have obtained rich collections. The
investigations and descriptions, by these gentlemen, of some of the fossils
from the same localities, have been so nearly contemporary with my own, that,
from want of the opportunity of comparison of specimens, we have no doubt
in some cases described the same things under different names, and thus pro-
duced some confusion, which can only be corrected in future.

My investigations, in many instances, may appear not so complete as would
be desirable, and my excuse for not doing the work more thoroughly is the
limited time allowed for the purpose and the little leisure I have had in the
intervals of other and necessary professional engagements.

EXTINCT VERTEBRATE FAUNA OF THE BRIDGER TERTIARY
FORMATION OF WYOMING TERRITORY.

INTRODUCTION.

The following pages contain a liescrijjtion of foysil remains of vertebrated
animals collected in the vicinity of Fort Bridger, a military post situated in
the southwest corner of Wyoming Territory.

Many of the specimens were obtained during Professor Hayden's geological
explorations of 1869 and 1870, but the greater part of them were collected
during the same years and the succeeding one by Dr. James Van A. Carter,
residing at Fort Bridger, and by Dr. Joseph K. Corson, United States Army,
the surgeon of the post. These gentlemen have diligently explored a wide
extent of country in their immediate neighborhood in the search for fossils
with the most intelligent interest. The results of their explorations they
h:ive liberally placed at the service of naturalists by voluntarily donating
all the more characteristic portions of their collections to the Academy of
Natural Sciences of Philadelphia.*

After the present work was supposed to be nearly ready for the press, and
the accompanying plates from I to XXII were complete, the last summer, the
writer received a pressing invitation from his friend Dr. Carter to visit him
at Fort Bridger. As the invitation was accompanied with liberal facilities
and offers of aid in exploration, the author availed himself of the opportunity
of visiting a region of so .much interest, and accordingly spent the summer
vacation in a trip to the locality.

Fort Bridger occupies a situation in the midst of a wide plain at the base of
the Uintah Mountains, and at an altitude of nearly seven thousand feet above
the ocean-level. The neighboring country, extending from the Uintah and
Wahsatch Mountains on the south and west to the Wind River Range on the
northeast, at the close of the Cretaceous epoch, appears to have been occupied

* In speakiug of this institutiou hereafter I shall briefly refer to It as the Academy,
or the Academy of Phihulelphia.

by a vast fresh-water lake. Abundance of evidence is found to prove that
the region was then inhabited by animals as numerous and varied as those of
any other fauna, recent or extinct, in other parts of the world. Then, too, a
rich tropical vegetation covered the country, in strange contrast to its present
almost lifeless and desert condition.

The country appears to have undergone slow and gradual elevation ; and
the great Uintah lake, as we may designate it, was emptied, apparently in suc-
cessive portions and after long intervals, initil finally it was drained to the
bottom.

The ancient lake-deposits now form the basis of the country, and appear
as extensive plains, which have been subjected to a great amount of erosion,
resulting in the production of deep valleys and wide basins, traversed by
Green River and its tributaries, which have their sources in the mountain
boundaries. From the valley of Green River the flat-topped hills rise in suc-
cession as a series of broad table-lands or terraces, extending to the flanks of
the surrounding mountains.

The snows of the Uintah, Wahsateh, and other mountain-ranges are a
never-failing source to the principal streams ; but many of the lesser
branches, dependent for their supply on the accumulated snows of winter in
ravines of the lower hills and plains, completely dry up as the snows disap-
pear with the approach and advance of summer. The country for the most
part is treeless and destitute even of large shrubs, excepting along some of
the water-courses. The principal streams are fringed with trees, consisting of
cotton-wood {Populus angustifolia) and willow, (Salix longifoUa ;) and the
valleys through which they run produce mostly rushes (Juncus baltlcus) and
sedges, with some coarse grasses, as Eli/ in us condensatus and Triticum repens.
Hollows of the liills and narrow valleys, favorable to the retention of moisture,
support foi'ests of small aspens, {Fopulus tremuloides.) The higher terraces
and foot-hills approaching the mountain-ranges are covered with dense forests
of aspens, pines, {Pinus ponderosa and P. fle.rUis,) and firs, (Abies Menziesil,
A. Engelmanni, A. grandis, SjC.,~) with a rich undergrowth of herbaceous
plants. The great mountains themselves present a broad belt of pines and
firs, from which project the rocky sunrmits as bare of vegetation as the wide
plains at their l)ase. Many of the lower hill-sides and hollows in certain
situations are sparsely covered with cedars, (Juniperus virginiana,) most of

which are very okl in appearance and remarkably distorted, twisted, and
broken.

The principal growth of the plains consists of sage-l>ushes {Arteiiiesia tri-
dentatii) curiously distorted and split, so as to I'eniind one of the cedars just
mentioned. In some places the sage-bushes are mingled witii or replaced I>y
the gi-ease-wood, {Sarcobatus vermiculatus.) Wide, bare, path-like intervals
surround the bushes, or the spaces are occupied by scanty grass, which
formerly furnished food to the buffalo, now become extinct in this region
and elsewhere west of the Rocky Mountains.*

The fossils which form the subjects of our communication for the most
part were derived from tire more superficial deposits of the great Uintah basin,
which Professor Hayden has distinguished as the Bridger group of beds.
These compose the terraces or table-lands in the neighborhood of Fort
Bridger, and consist of nearly horizontal strata of variously colored indurated
clays and sandstones. As the beds wear away, through atmospheric agencies,
on the naked declivities of the flat-topped hills, the fossils become exposed to
view and tumble down to the base of. the hills among the crumbling debris
of the beds.

The flat-topped hills or terraces of the Bridger basin, rising from Ijroad
valleys and extended plains, form the most conspicuous objects of the land-
scape. A similar condition of the country, alternating with boundless plains
and great mountain heights, forms a charactei'istic feature of a great part ol
the region west of the Mississippi.

The flat-topped hills, table-lands, bench-lands, or terraces, as they are
variously named, seen from lower levels, are usually called "buttes," especially
when they are of limited extent. The name is of French origin, and signifies
a bank of earth or rising ground. The name is likewise applied in a more
restricted sense to the prominent irregularities of the deeply eroded and
naked declivities of the more extended terraces. The buttes therefore vary
in extent from a mere mound rising slightly above the level of the plains to

* It has already become a question whether the buffalo existed west of the Eocky
Mountains at a couiparativelj' recent period. That it did so was amply proved to the
writer from his having noticed rem.ains of the animal in a number of places, from ravines
skirting the Union Paciiic liailroad to the forests high up in the foothills of the Uintali
Mountains. Judge W. A. Garter, of Fort Bridger, informs us that some of the old trap-
pers iuid hunters of the district had told him that in their early days they had seen the
buffalo in abundance in that country.

hills of varied configuration reaching to the level ol' the broarler buttes or ter-
I'aces. In the course of ages the wearing away of these has been enormous
and still continues under the usual atmospheric agencies, while the detritus
is spread out on the plains below.

From the lower plains the neighboring terraces, when of circumscribed
extent, appear like vast earth- work fortifications, and when evenly preserved on
the declivities for a considerable distance remind one of long railway embank-
ments. Frequently the terraces are so extensively eroded and traversed by
nai'row ravines that they appear as great groups of naked buttes rising from
the midst of the plain, or assembled around the horizon closely facing and
flanking the more distant and extended lands as if to protect them. Nothing
can be more desolate in appearance than some of these vast assemblages of
crumbling buttes, destitute of vegetation and traversed by ravines, in which
the water-courses in midsummer are almost all completely dried. To these
assemblages of naked buttes, often worn into castellated and fantastic forms,
and extending through miles and miles of territory, the" early Canadian
voyageurs gave the name of "Mauvaises Terras'' They occur in many local-
ities of the Tertiary formations west of the Mississippi River.

In wandering through the "Mauvaises Torres,'' or "Bad Lands,'' it requires
but little stretch of the imagination to think oneself in the streets of some
vast ruined and deserted city. No scene ever impresed the writer more
strongly than the view of one of these Bad Lands. In company with his
friends, Drs. Carter and Corson, he made an expedition in search of fossils
to Dry Creek Cation,* about forty miles to the southeast of Fort Bridger.
The canon, or valley, is bounded by high buttes, and contains a meadow of
rushes, traversed by a stream which is liable to be dried up in the latter part
of the summer, whence the name of the canon. On ascending the butte to the
east of our camp, I found before me another valley, a treeless barren jilain,
prol)ably ten miles in width. From the far side of this valley butte after
butte arose and grouped themselves along the horizon, and looked together
in the distance like the huge fortified city of a giant race. The utter desola-
tion of the scene, the dried-up water-courses, the absence of any moving

* The same uame is so frequently applied to difierent places as to lead to consider-
able coufiision. When I speak of Dry Creek Caiion, I refer to a locality forty miles
from Fort Bridger; and when Dry Creek is named, it refers to another locality ten miles
from Fort Bridger.

If)

ohjfcl, and the profound silence wliicli prevailed, produced a ieeling tluit was
positively oppressive. When I tlien thought of the buttes beneath my feet,
widi their entombed remains of multitudes of animals forever extinct, and
reflected upon the time wlieu the country teemed with life, I truly felt that
I was standing on the wreck of a former world.

The buttes are often specially designated from some supposed resemblance,
or other character, as Church Butte, Pilot Butte, Grizzly Butte,* &c.

As before intimated,, the more superficial table-lands of the Bridger basin,
as they appear in the vicinity of Fort Bridger, are composed of nearly hori-
zontal strata of various colored indurated clays and sandstones. In most
localities visited by the writer the clays predominate, and are usually greenish,
grayish ash-colored, and brownish. When unexposed they arc compact,
homogeneous, and of stony hardness. In composition they vary from nearly-
pure clay to si*ch as are highly arenaceous, and gradate into those in whicli
sand largely predominates, and they usually contain few or no pebbles. They
appear to be more or less fissnred, and break with an irregular and some-
what conchoidal fracture. Exposed to atmospheric agencies, moisture, and
frosts, they readily disintegrate, and the declivities of the buttes, generally
entirely destitute of vegetation, are usually invested with crumbling material
from a few inches to a foot or more in depth. When this loose material is
wet it forms tenacious mud, and along the course of streams in the ravines,
the deepest and most treacherous mire. Baked by the sun upon the plains,
it fixes the drift-pebbles and other stones as firmly almost as if imbedded in
mortar.

In some localities the clays of the buttes abound in fresh-water shells, as
Unio, Melania, Planorbis, &c. Less frequently in other places they con-
tain land-shells, as Helix, &c.

The sandstones are more frequently of various shades of green, but are
also yellowish and pass into shades of brown. They are compact and hard
when unexposed to the weather, and are usually fine-grained, but also occur

*This name is applied to an extensive chain of buttes about ten miles to the south-
east of Fort Bridger. Judge Carter informed me that the name originated from the
circumstance that an old trapper, Jack llobinsou, once reported that he had found a
])ctrilied grizzly bear on the Butte. From. the description of the petrifaction 1 have
no doubt it was that of the animal 1 have named in the succeeding pages, Paheosyops,
the skull of which resembles that of a bear.

of a gravelly coiLslitiilion. They arc fissured in comparatively large masses,
wliicli assume a rounded lorm as lliey are worn away, so that a ledge of
sandstone projecting from the declivity of a Ijutte will appear like a row of
cotton Itales. As they disintegrate less rapidly than the contiguous clays,
masses are olten ol)served resting upon cones and columns of the latter, con-
triljuting greatly to the picturesque and sometimes fantastic appearance of
the l)uttes.

Many of the table-lands and lesser buttes in the vicinity of the Uintah
Mountains are thickly covered with drift from the latter, consisting of gravel
and bowlders of red and gray compact sandstones or quartzites. The drift
material is usually firmly imbedded in the surface of the plains so as to
appear like a pavement. The bowlders are generally small, but assume larger
proportions approaching the Uintahs. In many cases the drift completely
covers the terraces or buttes, descending upon the declivities s© as entirely to
conceal their structure. Usually, however, it accumulates in the ravines of
the declivities, leaving bare the intervening ridges of light-colored clays and
sandstones. Many of the buttes are nearly or quite free of drift material.
Some, again, are strewn with fragments of rock, consisting of tlie harder materials
from the terraces themselves, and these likewise occur mingled with the
drift-pebbles and bowlders from the mountain-heights.

The stone-fragments from the buttes consist of harder siliceous and cal-
careous clays, impure limestones, jaspers, and less frequently agate and chalce-
dony. In some instances they consist of singularly black incrusted and
niinided sandstones, somewhat of the character of scptaria. Specimens ot
these occasionally !;)ear a resend:)lance to fossil turtles, and when found wWh
I he harder crust broken tluy look like turtle-shells filled with a sandstone
matri.x.

In the buttes in the vicinity of Carter Station, on tiie Union Pacific Rail-
road, I observed many large nodular and cylindroid masses of agate. These
have a concentric arrangement of layers resembling that of fossil wood, for
which they arc, taken. Many of the masses contain a nucleus of amber-
colored crystals of calcitc.

Nodules of chalcedony wilh dendritic markings occur in some of the
buttes. These, together with the condition of many of the fossils of the
buttes, indicate the presence of a considerable proportion of soluble silica in

the waters of tlie ancient lake. In sonic ol' tlie sandstones, the fossil shells
have had their lime completely replaced by clear chalcedony.*

Occasionally strata of limestone, mostly impure from the admixinre of elay
and sand, arc found in some of the buttes. A frequent constituent also is
tiltrous arragonitc, or satin-spar, in tliin seams. Many of the bare mounds of
clay among the buttes are thickly strewn with fragments of this arragonite.

The stones imbedded in the surface of the plains and Inittes, in some
positions favorable for the purpose, are highly polished from the conjoined
action of the wind and sand, and when seen in the slanting light of the early
morning or evening sun, appear like myriads of scattered mirrors. In many
positions, the stones, no matter what may be their composition, are all black-
ened. The phenomenon I could not explain.

In many places the stone-fragraents from the declivities of the terraces,
strewn over the lower buttes or distributed over the plains, are splintered or
flaked in a remarkable manner. The jaspers esi^ecially are often broken in
such a way that they appear as spawls from rude implements of art, or even
resemble the latter. Some of them are certainly the work of primitive man,
I)ut the vast proportion, often scattered over miles of surface, are probal)ly
accidental forms.* These I suppose to have been produced by stones striking
one another in the descent from declivities as they have been carried down,
perhaps by glacial movement. The softer rocks of the buttes, those which
are too soft for stone works of art, are also observed broken in the same way
as the hard ones. In experimenting on some large splintered slabs of jasper
from the buttes of Dry Creek Canon, I found that a quick blow of a hammer
would send off, with a ringing sound, a long sharp flake, reminding me of the
primitive knives or scra])ers of the stone age of man.

Between the well-finished implement and the accidental spawl every gra-
dation of form may be observed among the scattered stones of the plains and

* Perhaps much of this soluble silica may have been supplied by hot springs still so
frequent in Wyoming and other Western Territories. Cold springs, slightly alkaline,
may have also coutributcd to the petrifying silica. In Pioneer Hollow, flfteen miles
west of Fort Bridger, I observed a dozen springs within the distance of a mile, tiie
water of which reminded me of the congress- water of Saratoga, New York. It is cool
and clear, highly carbonated, slightly alkaline, and agreeable to the taste. The springs
are circular, from 1 to 15 feet across, and are surrounded with dome-like craters from
1 to 3 feet high. The craters are formed of a siliceous sinter, which has been slowly
deposited from the spring- water, and is probably the accuniulation of ages, The sinter
is brown from the presence of iron, though the water has no perceptibly ferruginous
appearance or taste.

Ijiittes. The accompanying- figures, from 1 to 12, represent some of the
Haked stones, most of which, and perhaps all, are rude works of art.

Many of the accidental forms, as well as those more nearly resembling
artificial implements, if they are not actually such, appear greatly to differ in
age. Some of the specimens are as sharp and fresh in appearance as if Ijut
recently shivered from the parent block, while others are so mucli worn and
so deeply altered from exposure that they look to be of ancient date. In
some of these old-looking specimens .the jasper, originally brown or black,
has become dull white and yellow tlie depth of one-fourth of an inch from
the surface.*

*Iu tbis relatiou I luay take the opportuuity to refer to one of the simplest of stoue
iiuplemeuts, still in use, and which, if it had alone been found among the flaked ma-
terials of the butte.s, would certainly have been viewed as an accidental spawl. During
uiy stay at Fort Cridger, the Shoshone Indians made a visit to the post and encamped
in its vicinity for a week. Being the first time that I had had an opportunity of seeing
a tribe of Indians, I felt much interest in observing them. While wandering through
their camp I noticed the women dressing buffalo-skins with a stone implement, the
only one of this material I found in use among them. A serrated scraper of iron was
also employed, but the stone implement was clearly a common and important one. It
was a spawl from a quartzite bowlder made by a single smart blow with another stone.
It is circular or oval, plano-convex, and with a sharp edge. The implement is repre-
sented in the accompanying figure 13, and according to Dr. Garter, who is quite
familiar with the language and habits of the Shoshoues, is called by them a " te-sho-a."
By a happj^ accident I learned that it was not a mere recent instrument incidental to
the time and place.

While on an excursion after fossils, in com])any with Dr. Carter, I noticed on the side
of a butte a few weathered human bones, to which I directed the attention of my friend.
On further examination, we found others, together with some perforated canines
of the elk and one of the identical "teshoa" above described. Dr. Carter observed
that the Shoshones sometimes buried their dead upon the top of prominent buttes,
and these remains had fallen from the grave of a squaw, which in the cour.se of time
had become exposed by the wearing away of the edge of the butte. The bones and
elk-tusks were much weathered. Their appearance and the probable circumstance
that several years had elapsed before the butte could wear away to reach 'the grave,
appear to be sufBcient evidence that the "teshoa" was an implement of common use.

To this note I may add a remark relating to the perforated canines of the elk. They
are worn as ornamental trophies by the Shoshones and other Indians. In a recent
number of the American Journal of Science and Art, for 1872, page 211, in a notice
"On fossil man of the cavern of Brousse-rousse, in Italy, by E. Riviere." I notice that,
besides a human skeleton associated with the bones of many extinct animals, there
were also found several flint knives and a number of perforated canines of the stag.
In addition to the common form of many of the stone implements, this is a significant fact
bearing on the probability of a common origin to the races of man. One of the siieci-
mens of perforated tusks of the elk from the Indian grave is represented in Fig. 11,
at the end of this introductory chapter.

As the clays ami saiulstoiies of the Bridger terraces and builds cniiiiblo
away, a variety of renuiins of terrestrial and fresh-water animals are exposed
(o view. lu some of the buttes they are comparatively aljundant; in otiiers,
they are rare. The fossils consist of the bones and teeth of vertebrates, and
the shells of molliisks. Fragments of silicified wood also occur, though
not frequently. Shells of the san.dstones are composed of chalcedony ; Ijut
those imbedded in the indurated clays usually retain their carbonate of lime

The fossil bones are completely petrified ; that is to say, their more per-
ishable constituents have been replaced mainly by siliceous matter. They
are frequently as black as ebony ; and the teeth are usually black, with the
enamel highly lustrous. Often they are brownish, with a greenish aspect,
derived from the greenish matrix in which they were imbedded. They are
also found of a yellowish clay color and duller aspect.

Many of the bones are more or less crushed and distorted, as a result of
the pressure of the superincumbent strata. The fragments are generally but
slightly dislocated, showing that the crushing occurred while they were
imbedded. The stronger bones are often well preserved, especially the rami
of lower jaws and teeth, and the smaller bones of the wrist and ankle.
Whole skulls are exceedingly rare, and when discovered are much crushed
and distorted. ' Turtle-shells are among the most frequent fossils, but are
usually more or less fractured, crushed, and distorted. In searching over
the buttes, little piles of bone-fragments are often seen diverging froni a
prominent point. These, on examination, generally prove to be the remains
of a turtle-shell which, after exposure, has fallen to pieces.

Generally the fossils are sharply preserved ; that is to say, they rarely
have a rolled or water-worn appearance, indicating that bones and shells
were soon enveloped in mud at the bottom of comjjaratively quiet water. In
the gravelly strata rolled fragments of bones are found.

Nearly all the fossils collected from the Bridger I)eds, and descriljed in
the succeeding pages, have been collected as loose specimens picked up on
the surface of the buttes. No excavations have been made into the latter in
search of fossils, except to exhume a partially exposed bone, or some parts
of a skeleton supposed to be contiguous to specimens lying in view on the
surface. Usually only a few pieces of a skeleton have been found together,
and in no instance has a complete one been discovered which has been
brought to my notice. Generally, too, there has been no certainty that bones

or iVagments tbiiiul together belonged to tlie same .skeleton, and in must
instances they have appeared to belong to several ditierent animals.

The remains of vertel)rates thus far discovered in the Bridger Tertiary
formation represent all classes except Batrachians, and these no doubt
formed members of the ancient fliuna : but their delicate bones have, as yet,
escaped detection.

The remains of mammals are especially numerous, and they belong to
many genera, most of which are extinct, and had not been previously
described or tbund elsewhere. The greater proportion of the mammals were
odd-toed pachyderms, whose nearest living allies are the tapirs. Proboscidian
and equine forms appear to have been sparsely represented. Even-toed
pachyderms were comparatively few ; and ruminants, whose remains are so
abundant and varicil in the later Tertiary formations east of the Rocky
Mountains, appear to have been absent. The other remains of mammals
belong to rodents, insectivores, and carnivores, nearly all of extinct genera,
not previously described nor found in other localities. Primates, bats, mar-
supials, and edentates are probably represented, but have not been certainly
recognized among the fossils which I have had the opportunity of examining.
The nature of the formation from which the remains are obtained is such
that we do not expect to find evidences of the remaining orders of mammals.

No remains of birds have come under my notice; but Professor Marsh,
who has explored the Bridger Tertiary beds with unusual facilities and great
diligence, has reported the discovery of specimens which he attributes to half
a dozen species of two extinct and previously unknown genera.*

Of reptiles, the remains of turtles are, perhaps, the most abundant fossils
met with in the buttes of the Bridger basin. They belong to a number of
different genera, several of which are extinct, but others belong to genera
still in existence. Most of them are aquatic forms, but one at least was a
land-tortoise. The number of species and genera is in striking contrast with
the single species, represented by a multitude of individuals in the Tertiary
deposits of White River, Dakota, and of Niobrara River, Nebraska.

The turtle remains mostly consist of the shells, often nearly complete,
and sometimes including other bones ot^ the skeleton imbedded in the interior
matrix.

The remains of crocodiles, which are entirely wanting in the White

* Am. Jour. Sc, 1872, p. 25G,

River iind Niobrara Tertiaries just mentioned, are frequeiil in the Ijiidger
beds, and represent several species.

Remains of lizards also, allied to the modern iguana and monitor, are
found as associates of the Bridger fauna. Professor Marsh has likewise
reported the discovery of remains of serpents, which he ascribes to several
species and genera.

Multitudes of well-preserved fresh-water fishes are found in the Green
River shales. They are chiefly cypi'inodonts and herrings, and, for the most
part, have been described by Professor Cope.

Black, shining, enameled scales, teeth, and vertebrae of ganoid fislies are
frequent among the fossils of the Bridger beds.

The Tertiary strata of Green River and its tributai'ies, including the
latter, as indicated l)y the character of the vertebrate fossils, are much older
than the tertiaries of the Mauvaises Terres of AVhite River, Dakota, and of
the Niobrara River, Nebraska. They overlie the cretaceous rocks, with wiiich
they are unconformable, and they are probably contemporaneous with the
Eocene formations of Europe.

Attention was first directed to the Green River Tertiary formation,
which has proved to be so rich in tlie remains of vertebrates, by the late Dr.
John E. Evans, as early as 1856. From Green River he obtained a speci-
men of shale, witli a well-preserved fish, represented in Fig. 1, Plate XVII,
of tlie present work, and briefly described by the writer, under the name of
Clupea humiUs, in the proceedings of the Academy of Natural Sciences of
Philadelphia, for October, 1856.

In 1868 Dr. J. Van A. Carter, of Fort Bridger, in correspondence with
the author, informed him of the frequent occuri-ence of the remains of turtles
and other animals in the buttes of the neighboring country. The same year
Professor Hayden, during his geological explorations, obtained remains of a
Trionyx from Church Buttes. Colonel John H. Knight, United States Army,
also procured a vertebra of an extinct crocodile from the same formation of
Bitter Creek. These remains, together with those of a small insectivorous
animal, discovered liy Dr. Carter on the Twin Butte, near Fort Bridger, were
described by the writer in the Proceedings of the Academy for April, 1869.
The little insectivore was named Omomys Carieri in honor of its discoverer,
and is also described in " The Extinct Mammalian Fauna of Dakota and
Nebraska." The specimen upon which it was characterized is represented in
4 G

Figs. 13, 14, Plate XXIX, of that work. Subsequently, during 1869 and the"
ibllowing years down to the present time, the Green River basin has been
sedulously explored by Professor O. C. Marsh with the most important and
fruitful results. In the abundance of fossils and the number of extinct genera
and species of vertebrates they represent, his collections are perhaps not
exceeded by any obtained from any one locality elsewhere in the world.
Professor Marsh has given a succinct account of the geology of the region in
the American Journal of Science for 1871, and in the succeeding volumes
brief descriptions of the many species and genera of extinct animals discov-
ered hy him.

In 1869 Professor Hayden, during his geological exploration of Wyoming,
also examined the Green River Tertiary formations, and designated the more
superficial ones under the name of the Bridger group. The fossils collected
from the latter were submitted to the examination of the writer, and are
briefly noticed in the Proceedings of the Academy for 1870, and likewise in
Professor Hayden's reports of 1870 and 1871.

During the same and the succeeding years down to the present time, Drs.
Carter and Corson explored the buttes in the vicinity of Fort Bridger and
discovered many important fossils. Their collections from time to time were
transmitted to the author, and by far the greater numl)er of the animals char-
acterized in the following paper are indicated from the specimens of these
collections. Most of them have also been briefly noticed in the later volumes
of the Proceedings of the Academy, and in Professor Hayden's reports for
1870 and 1871.

I may further remark that during the last summer Professor Cope made
an extended exploration of the Green River basin, and ol^tained large collec-
tions of fossils, to a full account of which we look forward with much interest.

Fig. 14. Perforated elk-tusk; oue of a uiimber of similar specimens fotiuil together with a "te.shoa"
and human hones which had fallen from an old Indian grave, at the edge of a butte, three miles from
Fort Bridger.

MAMMALIA.

Order Perlssodactyla.

Hoofed qiiat^rupeds, with functional toes in tlie hind feet, and often like-
wise in the fore feet, in uneven number. Arrangement of the constituent
Iol>es of the crowns of the molar teeth unsymmetrical. Feinur with a third
trochanter. Astragalus with tlie fore part divided into tvv'o very unequal
articular facets. •

PAL^OSYOPS.

Aniong the most aliundant and interesting of the mammalian remains from
the Bridger Tertiary group, wliich the writer has had the opportunity of
examining, are those of a genus of odd-toed pachyderms to which the above
name has been given. The specimens consist of fragments of jaws with teeth,
isolated teeth, small portions of other parts of the skull, articular ends of
the limb-bones, and some of the smaller bones of the feet.

The anatomical characters of the specimens indicate Palaeosyops to have
been more nearly related with the tapirs than to any other living animals.
The jaws were provided with nearly closed series of teeth in full number,
that is to say three Incisors, a canine, four premolars, and three molars to each
side of both jaws. The canines are as well developed proportionately as in
ordinary carnivores, and would lead one to suspect that perhaps Palaeosyops
used a mixed diet of meat and vegetables.

The genus was originally established in the Proceedings of the Academy
of Natural Sciences of Philadelphia for October, 1870, on specimens of teeth
discovei'ed at Church Buttes, Wyoming, during Professor Hayden's geological
exploration. It was subsequently indicated in Professor Hayden's Prelimi-
nary Report of the United States Geological Survey of Wyoming, published in
the spring of 1871, and is there arranged among the artiodactyl or even-toed
pachyderms. Much additional material, comprising many parts of the skele-
ton of the same genus, having been received from Drs. Carter and Corson,
its characters were more fully ascertained, and its true position as a perisso-
dactyl or odd-toed pachyderm determined. The later account of these is given
in Professor Hayden's Preliminary Report of the United States Geological
Survey of Montana, &c., published in the spring of 1872.

Since then Professor O. C. Marsh has published a notice in the American
Journal of Science of August, 1872, of some remains ascribed to two genera

with tlic iKuiies of PaliPosyops luul Liiiuiohyiis. From tlic iiotico it would
appear he has overlooked the description of Palaeosyops in the report last
mentioned. He intimates the reference of the genus to the Perissodactyls as
if previously nnknown, and suggests the reference of specime'ris to it in which
"the last upper molar has two inner cones," though it is distinctly stated in
the al)ove report that " the last upper molar of Palaeosyops has but a single
lobe to the inner part of the crown." Upon this character he founds the pro-
posed genus Limnohyus, which,' under the circumstances, appears untenable ;
but if a pair of lobes to the inner part of the crown of the last molar be con-
sidered a distinctive generic character, the name might be transferred to the
geiuis possessing it.

The skull of Palseosyops, and the same may be said of other parts of
the skeleton so far as they are known to us, approximates in form and
constitution those of its probably- contemporaneous ally, the Palseotherium
of the Eocene period of Euroi>e. In both genera the skull presents a
broad, triangular forehead. In Palaeosyops it is more prolonged posteriorly,
and is more abruptly curved forward to the root of the muzzle. In both the
temporal fossae are very capacious, indicating masticatory muscles approaching
in power those of the great carnivores. In Pateosyops they are separated by
a much shorter crest than in Pateotherium. In the former the muzzle is rather
abruptly prolonged forward from the l)ase of the forehead ; in the latter the con-
vexity of the forehead is continued in the muzzle to tlie end of the nose. In
both genera the muzzle is broad, but in Palaeosyops the nasals are longer and
project forward as much as the jaws. The lateral nasal notch is nearly alike in
both, but is longer in Palaeosyops. In both, the orl)its are open behind, and are
defined from the temporal fossffi by long, angular post-orbital processes. The
jaws nearly repeat one another in the two genera. The number of teeth,
their kind, relation, and general construction, are likewise the same. In
Palaeosyops they form more unbroken series in the two jaws, as tlu; hiatus
back of the canines, which is comparatively .large in Paleeotherium, is very
trilling in extent in Palaeosyops.

Pal/eosyops paludosus.

The species Valceosxjops paludosus was first indicated under this name in the
Proceedings of (he Academy of Natural Sciences of Philadelphia in 1870, and
was founded on a number of isolated teeth and fragments of others oI)tained by
Professor Ilayden at Church Buites, Wyoming. Of the specimens, a last

ujipcr pt'cmdlar is represented in Fig. 5, Plate V; a t'nignieiit of a second
upper molar in Fig. 6, Plate XXIII, and two lower premolars and a molar
ill Figs. 3 to 5, of tlic same plate. The teeth apparently all belonged to the
same individual, which had reached maturity, but had not advanced so llxr as
to have the summits of the tooth-lobes worn through so as to expose the
dentine. The enamel is longitudinally wrinkled on the sides of the true
molars and in a less degree on the premolars.

The last upper premolar (Fig. 5, Plate V) has a trilolate crown consisting
of an outer pair of acute pyramidal lobes, and an inner larger conical lobe
embraced by a basal ridge in front and l^ehind.

The fragment of an ui)per molar (Fig. 6, Plate XXIII) consists of the tore
jiart of the crown, and is composed of an outer crcscentoid pyramidal lobe
and an inner smaller conical lobe. A strong convex buttress forms tiie aiitero-
external angle of the crown, and a moderate basal ridge bounds it in front.
A conspicuous tubercle, the rudiment of an additional lobe, occu|>ies the angu-
lar interval between the principal lobes and the basal ridge.

The lower molar tooth (Fig. 5) has a fore and ait bilobed crown as in
PaliEotheriuin and Titanotherium. The lobes arc crcscentoid pyramidal, and
the anterior is the smaller.

The lower premolars have the same essential constitution as the true molar,
but are less well developed. In the fourth premolar (Fig. 4) the relative size
of the lobes is reversed, the anterior being the larger, and the postero-internal
liuttress of the crown is obsolete. In the third premolar (Fig. 3) the j^jste-
rior lobe is still more reduced in size, the anterior lobe is proportionately
enlarged, and the inner buttresses of the crown are obsolete.

The measurements of the specimens are as follows :

Lines.

Fore and aft diameter of second uppci' luolar, estimated 17

Transverse diameter of second upper molar IS

Fore and aft diameter of last upper premolar !»A

Transverse diameter of last upper premolar ■ 1'2

Fore and aft diameter of second lower molar 10

Transverse diameter of second lower molar 10

Fore and aft diameter of fourth lowei' premolar ". 9i

Trauisverse diameter of fourtli lower premolar (>i

Fore and aft diameter of third lower premolar ..... S|

Transverse diameter of third lower premolar. ; ~>

Shortly after the original description of the above specimens, several others

were received from Professor Hayden, obtained on Henry's Fork of Green
River, Wyoming, wliioli are referred to in the last paragraph of the same
article of the Proceedings above mentioned as the former ones. The addi-
tional specimens consist of several small jaw-fragments, with teeth, belonging
to an individual past maturity, as indicated by the worn condition of the
latter.

One of the specimens, a much-worn last upper premolar, is represented
in Fig. 4, Plate V. It agrees with the corresjjonding tooth above descrilied
l)()th in form and proportions. The summits of the three lobes of the crown
arc worn down so as to expose large tracts of dentine.

A second specimen consists of an upper-jaw fragment retaining a portion
of tlie first molar and the complete second one. The former was so much
worn as to have a great part of the enameled triturating surface removed.
The sccon'd mohu.-, represented in Figs. 8, 9, Plate V, has a low trapezoidal
crown composed of four lobes, of which the anterior two agree in constitu-
tion and proportions with the fragment of the corresponding tooth above
described. The outer pair of lobes are crescentoid pyramidal and bounded
externally by strong convex buttresses. The inner lobes, of which the an-
terior is much the larger, form broad cones. A strong basal ridge bounds
tlie crown in front. The enamel is worn smooth and is abraded from the
summits of the outer lobes so as to expose broad dentinal tracts. The fore
and att diameter of the crown of the second upper molar is 16^ lines; its
transverse diameter is 18 lines. The remaining specimen consists of an
upper-jaw fragment containing the last molar, represented in Figs. 6, 7,
Plate V The tooth is fractured and its parts somewhat dislocated, so as to
extend its breadth. It has the same constitution as the former tooth, except
that it has ])ut a single internal lobe, which in great part is broken away in
flic specimen.

Many more complete specimens referable to Palceosyops paludosus have
been received from Drs. Carter and Carson. One of the most important of
these consists of the facial portion of a skull containing nearly all the molars
and the canines of both sides. The specimen submitted to my examination
bj D.r. Carter, represented in Fig. 51, Plate XVIII, was discovered in a
greenish frialde sandstone of the Grizzly Buttes. The tixce is entirely broken
away at its upper part and fore extremity. The molar teeth, of which a full
scries is represented in Figs. 3, 4, Plate IV, are fijr the most part preserved

entire, but the canines, of which one is represented in Figs. 2, 3, arc broken
off at the crown. Tlie specimen pertained to an individual past maturity, as
indicated by the worn condition of the teeth. Tiie enamel is ai)radcd from
the summits of the outer lobes of the last premolar and the molars and the
summits of the inner lobes of the first molar, so as to expose tracts of den-
tine. Elsewhere the enamel is worn smooth, but remains of its original
rugose condition are yet visible in the last molar. In anatomical character
and proportions the teeth agree in all respects with those corresponding
among the specimens above described.

The molar series consists of seven teeth which successively increase in
size from first to last. The molars or true molars approach in character those
of Titanotherium, and in a less degree those of Anoplotherium and Chalico-
therium. The crown is broad and low and rather rhombic in outline. It is
composed of four principal lobes expanding in a common base. The outer
lobes are the larger and have the shape so common in many allied animals as
Palisotherium, Ancliitherium, Anoplotherium, Oreodon, Cervus, &c. They
are three-sided pyramids with crescentoid summits, the anterior extensions of
wliich form stout external buttresses to the crown. The inner lobes are
broad cones less prominent than the outer lobes. Tlic anterior is the larger,
and is situated opposite the angular recess of the outer lobes; the posterior
occupies a position opposite the postero-internal face of the contiguous outer
lobe at the inner back corner of the crown.

A strong basal ridge occupies the fore part of the crown, and elements of
the same are found at the bottom of the outer faces of the external lobes. A
tubercle exists in the angular interval of the anterior lol)es and the basal
ridge in front, which looks as if it were the rudiment of the large antero-in-
ternal lobe in Anoplotherium and its homologue in ordinary ruminants.

In the last molar the postero-internal Ipbe, as existing in the molars in ad-
vance, is absent or is substituted by a small tubercle extending outwardly as a
posterior basal ridge to the crown.

In the unworn condition of the upper molars of PalfEosyops the external
lobes of the crown have acute crescentoid summits which conjoin on the sum-
mit of the median outer buttress. As the teeth were worn away in mastica-
tion, a W-shaped tract of dentine appeared on the outer lobes, and this gradu-
ally widened with the progress of abrasion. As the summits of the inner
lobes were worn away, circular islets of dentine made their appearance,

which likewise gradually expanded as a result of mastication. A continuance
of the process would unite the inner and outer tracts, and in an advanced
condition of abrasion the distinction of the four lobes with the intervening
valleys would be obliterated, leaving a broad concave dentinal surface bordered
by the enamel at the sides of the crown.

The upper molars of Pateosyops, while presenting considerable resemblance
to those of Pateotherium, also exhibit well-marked differences. They differ
especially in the greater prominence and more robust character of the ex-
ternal Ijuttresses of the outer lol^es, in the form and more complete isolation
of the inner lobes, and in the absence of the deep pit at the termination of
the oblique valley of the crown.

In comparison with the upper molars of Anoplotherium, those of Palfeo-
syops especially differ in having proportionately stouter buttresses to the
crown externally; in possessing but a rudiment of the antero-internal lobe as
existing in the former, and in the different shape and relationship of position
of the postero-internal lobe, whicli in Anoplotherium has the form nearly of
the contiguous outer lobe and embraces it as in the deer.

In comparison with the corresponding teeth of Chalicotherium, several ini-
poi'tant differences are observable. Of the outer buttresses of the crown in
this genus, the posterior is the larger, but in Pateosyops the anterior is the
larger. The antero-internal lobe is proportionately less prominent, and the
postero-internal lube has a different shape, being nearly like that in front of
it, and it is completely isolated. In Chalicotherium it is more like that in
Anoplotherium, and it joins the fore part of the postero-external lobe. In
flic last molar of Palseosyops the postero-internal lobe is obsolete, but in
Chalicotherium is proportionately as well developed as in the other molars.

As previously intimated, it is to the upper molars of Titanotherium that
lliose of Pateosyops have most resejnblance. The abrupt and deep pit near
the centre of the crown is absent. The rudimental lobe at the fore part of
the crown between the anterior principal lobes is proportionately less de-
veloped, and yet is more isolated from the basal ridge. In the last molar the
postero-internal lobe is nearly suppressed, while in Titanotherium it is still a
conspicuous clement of the crown, though less well developed than in (he
other molars.

The premolars of PaliEos3'op.s undergo a successive reduction forward and
assume a more and more elemental condition.

Tlio (burili prciiiular lias uii (iljloiiir stjuiiro crown uilh (lie, IraaHverse
diameter exceeding that fore and aft, and witli the inner part nearly semi-
circular. The crown is composed of three lobes, corresponding with the
outer pair of the molars, and apparently the large inner one situated opposite
the recess of the former. The outer lobes are like those of the molars, with
the back one proportionately less well developed, with the outer median but-
tress of the crown suppressed, and with the outer median fold of the antero-
external loI)e more prominent. The inner lobe is a single, broad, undivided
cone less prominent but rather larger than the outer ones. It appears to be
homologous alone with the anterior of the inner cones of the molars, and at
least does not appear to be a connate pair as in the corresponding tooth of
Titanotlierium. The conspicuous pit in the center of the crown in this
genus is absent in Palseosyops. A thin basal ridge starting in front and back
of the internal lobe festoons the crown outwardly and at the bottom externally
of the outer lobes.

The third premolar is a diminished representative of the one behind, but
has its antero-external lobe proportionately a little larger, and the [)ostcro-
external lobe proportionately reduced. The teeth of the two sides are not
symmetrical in the specimen. That opposite to the one represented in the
figure has its fore part broken away, but the postero-external lobe is consider-
ably longer than in the entire tooth.

The second premolar has a trihedral crown, in which but two lobes are
conspicuous. In comparison with the premolars behind, the internal loi^e is
greatly reduced in size, and the antero-external lobe is much enlarged so as to
become the main portion of the crown, while the postero-external lobe is ob-
solete.

The first premolar is a small tooth separated from the others by a slight
interval. It has a simple short conical crown with the base slightly extended
backward, and is inserted by a pair of fangs. The other premolars and the
molars are inserted with three fangs, of which the inner one in the latter
teeth consists of a connate pair.

The canine teeth of Palasosyops were powertul and efticient weapons, and
resembled those of ordinary carnivores more than they do those of nearly
allied living animals. Though imperfect in the specimen under consideration,
the remaining portions, as represented in Figs. 2, 3, Plate IV, indicate teeth
of the form and proportions of those of living bears. They also ajipear to
have nearly the same relative i)osition with the other teeth and the same

•34

direction ;i.s in Uil^ latlcr. Tlie fang is robust and gibbous, and comes from
the alveolus in a direction downward and forward with a greater degree of
divergence than usual among carnivora. The face of Palseosyops, judging
from the imperfect specimen, a side-view of which is given in Fig. 51, Plate
XVIII, in its complete condition, would appear to resemble in shape that of
tiie Elotherinm of White River, Dakota, cxcejit that the muzzle was pro-
■ portionately shorter. Among living animals, it appears to have resembled
that of the bears niort; than in those nearly related to it. The zygomatic
arches are of rol)ust proportions and widely divergent at their anterior attach-
ment to the face. The malar portion of the zygoma is divided by an acute
ridge curving from the anterior orbital margin outward, downward, and back-
ward. The surface above this ridge curves outwardly and downward from
the floor of the orbit continuously. The surface beneath is a broad trilateral
plane looking forward, downward, and outward, and is roughened for the at-
tachment of a powerful masseter muscle. The space behind the anterior
abutment of the zygoma indicates a temporal fossa of large capacity.

The orbit appears low, and is directed obliquely forward and outward.
In advance of the prominent antorbital margin the side of the face is nearly
vertical. The infra-orbital foramen is rather large, and is situated over the
position of the last premolar. In front of the foramen begins the swell of the
large canine alveolus, and below its position is the alveolar border, marked by
the vertical ridges of the molar fangs. The hard palate is well arched, and
nearly parallel at the sides. Its surface in the specimen is obscured by the
attachment of rocky matrix. The breadth of the face at the zygomata
appears to have al^out equaled the length.

The measurements of the specimen are as follows:

Inches. Liu6s.

Breadth of face at zygomata ou liue with middle of hxat molar.s 7 8

Breadtli of face outside of last molars i C

Breadth of face outside of canine alveoli 3 G

Breadth of face at infraorbital foramina 3 2

Breadth of bard palate between last molars 1 7

Breadth of hard palate between last premolars 1 o

Distance from back of last molar to fore part of canine 0 S

For comparison, the measurements of the teeth will be given after the
description of the following series.

Some additional specimens, which I suppose to belong to Palaosyops
paludosus., notwithstanding certain dilferences hereafter to be mentioned, con-

sist of most ot" the upper teeth, with small attached jaw-fragments, obtained
l)y Dr. Carter on Henry's Fork of Green River. Of these specimens a com-
])lctc series of nearly perfect molar teeth is represented in Figs. 5, G, Plate
IV. The teeth in their abraded condition ilidicate an older animal than that
to which the facial specimen above described belonged. The summits of the
constituent lobes of the teeth are nearly all worn to such a degree as to
exhibit tracts of dentine, and the enamel is everywhere smooth, except on
the external faces of the outer lobes near the basal ridge.

The molars are almost identical in character with those above described
ill the facial specimen. Trifling differences consist in the less production of
the median fold on the outer face of the external lobes, and perhaps the less
degree of prominence of the tubercle in the interval anteriorly of the anterior
pair of lobes. The last premolar is likewise identical with those above
described, except that its crown is rather more square, or is not quite so
wide. The anterior three premolars depart considerably from their character
in the facial specimen, and their differences may probably indicate a different
species. The third premolar is a diminished representative of the one behind
it, the three lobes of the crown holding nearly the same proportionate devel-
opment; whereas in the corresponding tooth of the facial specimen the pos-
tero-external lobe is considerably reduced in its proportions. In the second
])remolar the crown still retains a postero-external lobe reduced in proportion
to the others, but in the corresponding tooth alaove described it is obsolete.
The retention of this lobe gives the crown a greater fore and aft breadth than
that contained in the facial specimen. The first premolar has the same form
as that of the latter, but it is much lai'ger.

The mutilated canine, accompanying the molars first described, is repre-
sented iu Fig. 1, Plate IV, and is but little more than half the size of those
contained in the facial specimen.

An isolated incisor, represented in Fig. 8, accompanying the molars and
canine just described, is regarded as an upper one. Tiie crown is mutilated,
l)ut when complete appears to have had a short, conical crown, bounded
behind by a strong basal ridge. The fang is laterally compressed, and is
about an inch in length.

Comparative measurements of the series of teeth of the two individuals of
Palseosyops. indicated by the facial specimen, with teeth, from Grizzly Buttes,

and the specimens of (eetli IVoiu Henry's Fork, just described, are as
follows :

Si)ace occupied by the entire molar series
Space occupied by the true molar series .
Space occupied by the premolar series . .

Liucs.

G9
41

Lines.

71
■11
32

Diameter of lirst premolar .
Diameter of secoud premolar
Diameter of third premolar
Diameter of fourth premolar

Diameter of first molar

Diameter of secoud molar . .
Diameter of last molar

Autero-
jiosterior.

Lines.

7
10
12
1(3
17

Transverse.

Lines.

8
lOi
13
17

Antero-
posterior.

Lines.

8
12
15
17

Transverse.

Lines.

9
10
12i
W
IGJ

Lines.

Length of faug of upper canines

Autero-posterior diameter of canines
Transverse diameter of canines

28
12§

The question arises whether the differences which have been indicated in
the [)remolars and canines of the two different series of teeth above described
indicate more than one species. The differences are clearly in degree of
development and size, and these may probably be of a sexual character. The
individual with the more powerful canines I suppose to have been a male, in
which, with a greater proportionate degree of development of these oi'gans
than in the female, there appears to have been a reduction in the degree of
development of the anterior premolars.

Another sjieciinen submitted to my examination by Dr. Carter, and repre-
sented in Figs. 6, 7, Plate XXIV, belonged to an older animal than the
former, as indicated by the more worn condition of the teeth. The latter
consist of the anterior three premolars and a portion of the fang of the canine,
and they have the same form and proportions as the corresponding teeth
above described. The first premolar is close to the others, or is iiot sepa-

rated l)y a coiispiouoiis interval as in (he Ibrmer s[)ccini(ni. Tlie lolx's ol' llic
second anil third premolars are worn nearly to a level with tlieir l)ase. Tin;
outer surtiice of the maxillary, as seen in Fig. G, is defined by an oijliijiir
ridge at the nasal border, within which the suture of the premaxillaiy ])ur-
sues its course over the position of the fang of the canine. Just outside of
the nasal border the surface of the maxillary is depressed.
The measurements of the specimen are as follows :

Lines.

Space occupied by tlie anterior tln-ee premolars 21

Autero-posterior diameter of first premolar G^

Transverse diameter of first premolar 3;^

Autero-posterior diameter of second premolar 7

Transverse diameter of second premolar G^

Autero-posterior diameter of third premolar 8

Transverse diameter of third premolar 9

Diameter of fang of canine 8

Fragments of half a dozen lower jaws referable to Palseosyops, collected in
various localities in the vicinity of Fort Bridger by Drs. Carter and Corson,
have been submitted to my examination.

A well-preserved specimen, consisting of the greater part of the jaw, was
discovered by Dr. Carter imbedded in a greenish gravel thirteen miles soutii-
east of Fort Bridger. The right ramus is represented in Fig. 11, Plate V, and
it contains the molars and the back two premolars, which are also repre-
senteil with a view of the triturating surfaces in Fig. 10 of the same plate.
The teeth, corresponding with those in part upon which the species Palceo-
syops paludosus was originally indicated, are identical in anatomical chaiacter
and so nearly in size that the jaw may be regarded as pertaining to the sam(>
species.

In advance of the teeth retained in the jaw there are indications of two
additional jM-emolars verging close upon the remains of the canine alveolus,
and thus the specimen shows that the number of the lower molar series of
Palseosyops is seven.

The lower molars of Palaeosyops resemble those of Palseotherium and
Anchitherium, but even more closely those of Titanotherium. The crowns
arc ])roportionately wider and lower, or appear more robust than in the formei-
genera.

The crown of the anterior two molars is quadrately oblong oval, with the
fore and aft diameter largest and the depth less than the width. It is com-
posed of two divisions or lobes, one in advance of the other. The last molar

has llie same form and coiistriictioa, with the addition of a third but smaller
lobe.

In tlie ninvorn molars the principal constituent lobes present acnte cres-
centoid summits embracing a concavity which opens to its bottom by an
angular notch on the inner side of the crown. The contiguous arms of the
crescentoid summits conjoin in a strong conical eminence situated just in
advance of the middle of the crown internally. The point of this eminence
is simple or undivided ; in Anchitherium it is deeply indented and appears to
he composed of a connate pair of eminences.

The fore part of the summit of the anterior lobe in Palgeosj'ops curves
downward and inward, and ends in a slight prominence at the anterior inner
corner of the crown. The hind part of the summit of the posterior lobe ends
in a prominence like that in advance, but smaller, and situated at the postero-
internal corner of the crown.

Externally the lobes of the crown are angularly convex, and include deep
angular recesses sloping outwardly and downward, and bounded by festooned
elements of a basal ridge. The inner surface of the crown is nearly vertical,
smooth, and without a basal ridge. The latter is especially well developed
at tlie fore and back part of the crown, except in the last molar, in which the
additional lobe takes its place. This lobe is a much reduced likeness of those
in advance, with the arms of its crescentoid summit contracted and conjoined
with the posterior conical eminence of the crown internally.

The molars undergo a rapid reduction forward, and they are inserted by
two fangs. The crown of the last premolar is a reduced representative of
that of the succeeding molar, with the posterior lobe proportionately, in
comparison with the anterior lobe, less well developed. In the crown of the
third premolar there has been a further proportionate reduction in the back
lobe, but the anterior remains nearly the same, except that it appears more
robust from its connation with the homologue of the anterior of the inner
conical eminences of the teeth behind.

In Pateotherium and Anchitherium the corresponding premolars with those
described repeat the form of those of the molars, and in this respect greatly
differ from Palseosyops. The inferior premolars of Titanotherium in a perfect
condition are not sufficiently well known to instittvte a comparison with those
of Palseosyops.

The lower molars of Palseosyops in wearing would assume the same

apjiearance as those of Palaeotheriuin and Anchitheriiiin at the same stages <>(
attrition.

Tlie space occupied 1)}' the entire molar series is estimated at al»oiit G.^
inches, of whicli the true molars occupy ratlier less tlian 4 inches.

The measurements of the molar teeth contained in the lower jaw are as
follows :

Antero-
posterior.

Transverse.

Diameter of tbird premolar .
Diameter of fourth premolar

Diameter of first molar

Diameter of second molar. . .
Diameter of last molar

Lines.
8i
9

15
19

Lines.

8
10

The premolars are inserted by a pair of fangs, except the first, whicli has
but a single fang.

The lower jaw of Palceosyops, as seen in Fig. 11, Plate V, appro.ximates in
form that of the tapir and hog, though presenting important differences.
The dentary portion of the ramus is proportionately shorter and deeper than
in either of those animals, and the alveolar border is more ascending poste-
riorly. The base is more convex fore and aft than in the hog but less than
in tiie tapii', and is more obtuse than in either. The outer surface is vertical,
with a slight outward slope at the fore part.

The back part of the jaw is of more uniform breadth than in the tapir, and
is more like that in the hog. Toward the angle the outer surface is a verti-
cal plane, with the lower border or base more directed downwardly timn in
the hog. The upper or ascending portion presents a masseteric fossa about
as deep as in the tapir but of considerably greater width.

The condyle is large and thick, and much like that in the tapir, but is less
inclined inwardly. It has about the same proportionate elevation above the
level of the base of the jaw, but less above the level of the teeth.

The border of the jaw below the condyle behind is at first slightly concave
and then convex, as in the hog, but to a less degree. The coronoid process
is about as long as that of the tapir, but the fore part curves upward and
l)ack\vard without any inclination forward. The notch behind hardly descends
below the level of the condyle.

The mental turiiincii is siiiallcr tliaii in (ho tapir, and is .situated l)el()\v the
interval of the second and third picniolars

The length of the lower jaw, fi-om its back border to the fore part of the
second premolar, is [)'\ inches, and in the complete condition it measured
about 2 inches more.

Portions of several lower jaws, apparently all referable to Palseosyops, were
ol)tained by Dr. Corson at Grizzly Buttes. The specimens exhibit some
variation in character, and may, perhaps, belong to more than one species of
the genus. One of the specimens consists of a dentary fragment containing
(he true molars and the fangs of the two premolars in advance. The retained
teeth are like those previously described, but are in a trifling degree smaller.
The series measures 3| inches. The jaw-fragment nearly agrees with the
corresponding portion of the specimen above described, but is of more uniform
depth.

Another specimen consists of a right ramus, without the chin and back
part, and broken into three pieces. It contains the fang of the canine and
most of those of the molars. The jaw is of more uniform depth below the
position of the teeth than in the more complete specimen first described, and
more robust than in cither of the former specimens. The retained portion
of the fang of the canine indicates a larger tooth than existed in the first-
described specimen — one, also, that would accord in its robust character with
those of the facial specimen referred to Palceosijops iJcdudosus. The presence
of the fang of the canine produces a strong bulge at the side of the chin,
which apj/cars to have been comparatively feeble in the first-described speci-
men. Two mental foramina are situated below the position of the second
and third premolars. The first premolar appears to have had a single fang
consisting of a connate pair. It was separated from the canine and second
premolar by conspicuous intervals, the posterior of which is the larger. A
])ortion of the chin being retained in the specimen, it would a})pear in the
entire condition to form a broad slope defined at the sides liy the convexities
of the canine alveoli. The rami were completely co-ossified at the symphysis
witiiout the suture of union being apparent.

The remaining specimen consists of a portion of the jaw containing the
limgs of the last two molars, and the portion immediately jjehind extending
toward the angle. The dentary portion of the bone is considerably deeper
(hau ill (he corresponding portion of Ihe preceding specimens. The l)ase

below Uie posilum (if llic last nioliir lootli is rafhcr more eonspiciKiusly lulicr-
ous and roughened for muscular attachment, and the concavity back of this
is more posterior and deeper than in the first-described specimen.

Comparative measurements of the lower-jaw specimens, including the one
first described, are as follows :

Space occupied by tlie entire molar series

Space occupied by the molars and last two premolars .

Space occupied by the true molars

Distance from last molar to back of jaw

Width of ramus back of condyle

Depth of ramus at middle of last molar : . .

Depth of ramus below last premolar

Thickness of base below second molar

Anteroposterior diameter of last molar

No. 1.

Lines.

C4
.40
49
44
31
23
13
19

No. 2.

Lines.

05
48
48
41
3U
23
11
20

No. 3.

Lines.

00
4.5

33
20

12
19

No. 4.

Lines.
78

02
45

33
29
13
19

A small fragment of the chin of a lower jaw, referable to Paleeo.syops,
retains part of the alveolus of a large canine, and portions of the fangs of
three incisors of the same side, thus indicating the number of the latter teeth
in the animal. The canine alveolus has been about an inch in diameter. In
the ramus of the jaw above described, retaining the fang of a canine, this
tooth has been nearly in proportionate size to that of the alveolus just men-
tioned.

Small fragments from three different skulls, attributable to Palceosyops,
consisting of portions of two sagittal crests and the supra-occipital, indicate
capacious temporal fossa?, separated by a short, thick crest and a broad
occiput.

The fragments of sagittal crests arc from the fore part, retaining the suture
and notch for the summit of the frontal. The upper surface of the crest is a
flat triangle, slightly depressed at the middle, with the notch for the frontal
in its base. In the latter position it is li inches wide; and a couple of inches
back of this position the crest is !| of an inch thick.

The occipii'il fragment on each side in front presents a widc!, sloping sur-
face, which contributes to the temporal fos.sa. The posterior surface in
general ap])earance resemljles that in the rhinoceros. Tiie upjier ])ortion
forms a broad, even concavity, undivided by any trace of a vertical ridge, and
6 G

only loiigliened at tlic siiinmit for the attachment of the nuchal ligament.
The lateral processes are angular and ilivei-gent, and the space between them
is 4^ inches in width. The lower portion of the occipital surface approaching
the occipital foramen is convex. The height of the occiput fi-om the latter is
about 4f inches.

A lumbar vertebra was found by Dr. Corson at Grrizzly Buttes. It pre-
sents the ordinary ungulate form. The body is 2 inches long, but some-
what shortened below. It is concave fore and aft, at the sides, and beneath,
where it is also slightly carinate. The anterior extremity is slightly convex,
li inches transversely, and a little less in depth to the prominence beneath.
The posterior surface is .flat, or feebly depressed. The transverse process
springs from the upper level of the l)ody. A well-developed metapophysis
])rojects from the position of the anterior zygapophysis. The diameter of the
spinal canal is about an inch.

Besides the skull-fragments and vertebra of Palasosyops, a number of
isolated carpal and tarsal bones, and many fragments of the long bones and
other portions of the skeleton have been collected by Dr. Carter, Dr. Corson,
and Professor Hayden's party. Many of the bones had been fractured, or
more or less crushed, while they lay in their bed, and many have been further
injured after exposure through the influence of the weather and other causes.
The bones nearly resemble in size and construction the corresponding ones
of the American tapir.

The distal extremity of a humerus, represented in Fig. 3, Plate XIX, was
found by Dr. Corson in the vicinity of Fort Bridger. The breadth of the
specimen between the supra-condyloid eminences is 3^ inches. A deep
sujDra-condj'loid fossa occupies the front of the humerus, opposed to the
deeper and more capacious olecranon fossa. The articular trochlea is 2.]
inches wide in front, and narrows an inch less behind.

A mutilated femur, without the head and trochanters, represented in Fig. 1,
Plate XIX, was obtained on Henry's Fork, of Green River, by Dr. Carter.
In its complete condition it has approximated lo inches in length. The
shaft is three-sided, and at the middle is IG lines in diameter from before
backward, and 19 lines transversely. The median trochanter projects from
the outer border of the prismoid shaft, and is higher up in position than in
the tapir. The distal extremity resembles the corresponding part in the
latter, but the trochlea for the patella is of less breadth.

Fig. 2, Plate XIX, i-epreseuts a inucli better preserved distal extremity ol'
the femur than tiiat of the former. It was obtained by Professor Hayden's
party at Grrizzly Buttes. At the supra-condyloid eminences it is o^ inches
in diameter. The width at the condyles is 2f inches. The trochlea for the
patella, where widest, measures 16 lines.

The detached head of a femur, in perfect condition, found by Dr. Carter
near Fort Bridger, measures about 2 inches in diameter. A deep cup-like
pit for the round ligament approaches the center of the head much more
closely than in the tapii\

A nearly entire femur of Palseosyops, received from Dr. Carter since the
above was written, is represented in Fig. 5, Plate XXIX. It nearly repeats
the form of that of the tapir, but rather i-esembles that of the Indian tapir,
or Baird's tapii% of Gruatemala, than that of the American tapir. In compari-
son with that of the Taplrus Bairdi, it is rather larger, and the upper
extremity is proportionately somewhat wider. The inner trochanter is
longer or more prominent, but the third trochanter is neither so long nor so
hook-like.

The measurements of the specimen are as follows :

Inches.

Length externally from sumuiit of great trocliauter 15.J

Width between head and great trochanter 4i

Width at third trochanter 2|

Uiaiueter of head 2i

Diameter fore and aft of shaft at middle Ih

Width at condyles 3^

Fig. 1, Plate XX, represents a nearly entire tibia, obtained by Professor
Hayden's party at Grrizzly Buttes. The upper condyles are in some degree
pressed toward each other, and the extremity of the internal malleolus is
broken off. The bone is not quite so long as that of a tapir with which it
was compared, but is somewhat stouter. The tuberosity for the ligament of
the patella is of more robust proportions, and extends lower on the shaft than
in the tapii-. The ridge descending from it is thicker than in tlie latter —
straighter, and is obtusely rounded. The length of the tibia is 9 inches ; the
breadth of its distal end over 2 inches.

Fig. 2, Plate XX, represents a calcaneum, obtained l)y Dr. Corson near
the stage-route at the crossing of Smith's Fork of Green River. It is nearly
like that of the tapir, but is stouter in proportion to its length. The tuber-
osity of the calcaneum is less comjiressed and is more obtuse in liont. The

sustentaculum is of nuicli greater extent vertically, and sustains a long ellipti-
cal facet for the astragalus. The anterior articular facet for the latter is of
much less extent than in the tapir, and is more distinctly separated from it
by the interosseous sinus. The articidation for the cuboid is of greater depth
but less width than in the tapir.

The extreme length of the calcaneum is 4^ inches. The length of the
tuberosity is nearly 3 inches. The breadth of the anterior extremity of the
bone is 2 J inches.

Of two additional calcanea obtained by Dr. Carter, one was found on
Henry's Fork of Grreen River ; the other near Millersville.

Fig. 3, Plate XX, represents an astragalus found by Dr. Carter at the
bluffs, three miles from Millersville. The trochlea for the tibia is of less ex-
tent fore and aft than in the tapir ; and the anterior extremity of the bone is
of less width but greater depth. The length of the astragalus is 2 inches ;
the breadth of the trochlea twenty lines ; the breadth of the anterior ex-
tremity is the same, and its thickness is an inch.

Another astragalus, slightly larger, was obtained by Professor Ilayden's
party at Church Buttes.

Fig. 4, Plate XX, represents three tarsal bones obtained by Professor Hay-
den's party at Church Buttes. They pertained to the same individual, and
consist of the cuboid, scaphoid, and the outer cuneiform.

The cuboid is more cubical and stouter than in the tapir. The upper
surface is more regularly square and nearly a third wider than in that animal.
The articular facet for the calcaneum has about the same depth, but is nearly
twice the width. The facet for the first metatarsal bone is also of equal
depth, but a tliird greater in width.

The scaphoid is of rather less breadth than in the tapir, nearly of equal
depth, but not quite so thick. The articular facet for the astragalus is of
about the same extent, less breadth, Init proportionately more uniform depth,
and it is less concave. The articular facet for the outer cuneiform is of about
the same depth, but of much less breadth than in the tapir. The fiicets for
tiie inner two cuneiforms have about the same extent as in the latter.

The external cuneiform is about the same depth as in the tapir, l)ut of con-
siderable less breadth and of greater thickness.

The metatarsal articular facets of the cuboid and external cuneiiljrm ap-
pear to indicate that the outer toe of Palasosyops was as large as the middle

loc, and thai this was much smaller than in the tapir. This a[)|)cars to he
confirmed by the specimen represented in Fig. 5, Plate XX, which 1 suppose
to be a middle metatarsal of Palaeosyops. It was found by L)r. Corson in
the vicinity of Fort Bridger. It resembles the correspondibng one ol" the
tapir, but is shorter and of more slender proportions. It has about the size
of the lateral metatarsals of the tapir.

Figs. 6 and 7, Plate XX, represent a tirst and second phalanx, probal)ly of
Palaeosyops. The specimen of the first was obtained by Dr. Carter on Henry's
Fork of Green River; the specimen of the second was found near Fort
Bridger.

A specimen of a metacarpal, which I suppose to l)clong to Palseosyops,
was obtained by Dr. Corson at Grizzly Buttes. It has about the same length
as the middle metatarsal attributed to Palseosyops, but is somewhat wider.
If it corresponds with the second of the series of four toes of the fore foot
of the tapir, it exhibits a corresponding reduction in relation \vith the con-
tiguous toes that the middle metatarsal does to the others of the hind loot.

Palteosyops major.

A larger species of Palseosyops is apparently indicated by some fragments
of large bones obtained by Dr. Carter at Grizzly Buttes and other localities
in the vicinity of Fort Bridger. Several of the specimens consist of ])ortions
of limb-bones, but too much mutilated either for description or representa-
tion. Even the best specimen, consisting of a fragment of the lower jaw, rep-
resented in Fig. 8, Plate XX, is barely more than sufficient to render it
[)robable that it pertained to Palaeosyops. The jaw-specimen is furthermore
in some degree abnormal in form, due to inflammation or some other affection
connected with the second molar tooth. The bone outside the position of
the latter is much swollen, and the alveolar border is hollowed out and irregu-
lar. The alveolus is also filled with the clay matrix, so that the tooth \\as
perhaps lost before the death of the animal. In its proportions, the jaw, in a
normal condition, would appear to be of more robust character than in
Palceosyops pabidosus. In its present state, the base is more convex fore and
aft than in the latter, and the alveolar border more ascending posteriorly.

The remains of the molar fangs at the entrance of the alveoli appear to
indicate teeth of the same form and construction as in Falccosyojjs paludosus^

for whicli reason (he fragiiient was rei'erred t(j the same genus. The true
molars appear to have occupied a space of 4| inches, tlioiigh this is probably
somewhat exaggerated, as the interval occupied hy the last intermediate molar
appears proportionately somewhat too large. The crown of the last molar,
which was clearly trilobate as in Pal(zosyoj>s paludosus, had an antero-posterior
diameter of 2 inches.

The former existence of a larger species than Palceosyops paludosus, and
probably the same as that indicated under the name at the head of the present
chapter, is apparently confirmed by more characteristic .materials placed at
. my disposal by Dr. Carter in my recent visit to Fort Bridger. One of the
best preserved specimens consists of the greater part of the left ramus of the
lower jaw, containing six molar teeth, as seen in Fig. 1, Plate XXIII. The
jaw is considerably more robust than in those referred to Palceosyops paludosus,
though not to the degree I supposed from a view of the diseased specimen
above described. At the side it is more rounded toward the base, and is more
convex in a curving line from the root of the coronoid process beneath the
true molars, and is more bent inward and convex from the position just indi-
cated toward the technical angle of the bone. Rugosities of the surface in
several positions indicate stronger attachment of the soft parts, in accordance
with the greater bulk of the animal, than in Paloiosyops imludosus.

The true molars have the same form and proportions as in the species just
named. Trifling differences appear to be dependent only on a difference in
the robust character of the species. The external basal ridge is slightly bet-
ter developed, as is also the case with the median I'idge, descending on the
inner slope of the external lobes of the crown. The back lobe of the la.st
molar is also rather better developed, and incloses a shallower fossa on its
imicr side.

The first premolar, situated immediately behind the canine, is inserted by
a single fang, and is separated from the second premolar by a hiatus about a
third of an inch in extent. Below the hiatus, the jaw externally presents a
small concavity.

The last premolar has the same form as that in the jaw referred to
P(d(BOsyops paltidosus^ though, from its worn condition, it looks different. In-
dependent of this, it exhibits no diflerence except that the base in advance
of llu' anterior lobe is [)n>duc-cd exlcnially in a strong ridge.

The tliirtl prcinohir also is like that of PalfEosyops pnludos/zs, c\ce[)i'\ug that
it exhibits a tendency to the prudiiclion of a ba.sal ridge nut evident in
the former.

The second premolar, not present in the jaw-specimen of Pakeosyops
puludosus, is a reduced form of the tooth behind it. A portion of the canine
alveolus retained in the specimen indicates a tooth of moderate size in com-
parison with the size of the jaw itself

* Another series of lower molar teeth, attached to small jaw-fragments, and
represented in Fig. 2, Plate XXIII, also appear to me to be referable to
Pul(Bosyops major notwithstanding certain diiferences presented b^' the pre-
molars. The teeth are considerably more worn than in the preceding speci-.
men ; most of the summits of the constituent lobes of the crown of the mo-
lars and last premolar being so worn as to exhibii islets of exposed dentine.
The second molar is most worn, and presents on the summits of the outer or
principal lobes broad, depressed, shield-shaped tracts of dentine.

The molars have the same constitution as in the preceding specimen. The
last one is smaller, but the others arc nearly of the same size, except that the
iirst one is thicker, especially at its fore part, and is therefore of more uniform
diiimeter. The basal ridge of the anterior two molars is better developed
externally than in the former specimen. In the first molar the anterior lobe,
being proportionately rather better developed than in the corresponding tooth
of the previous specimen, its anterior ridge curving inwardly, is stronger, and
it embraces a more conspicuous fossa.

Tlie last premolar differs somewhat in proportions from that of the former
specimen, but is otherwise nearly the same, except so far as it is altered in
appearance from being more worn. It is of less breadth fore and aft, and
is thicker, and it docs not present the ridge at the fore part of the base,
externally, of the anterior lobe, being in this respect more like the corre-
sponding tooth in the jaw-specimen of Pulaosijops paludosus.

The third premolar differs from that of the former specimen very much in
the -same manner as the succeeding tooth. The crown is of less l)readtli fore
and aft, and is thicker. It has exactly the same constitution, but looks differ-
ent on account of its more worn condition, its difference of proportion, and
from the absence of a basal ridge occupying the fore part of the crown, exter-
nally, in the former specimen.

Comparative measurements of the teclh and jaws of the specimens just

referred to Pulccosyops major, and tlic jaw-specimen, witli teeth, of P. palu-
dosus, are as follows :

Depth of jaw at middle of last molar

De'lith of jaw at middle of last premolar

Thickness of jaw below interval of last two molars

Thickness of jaw below third premolar

Distance from canine alveolus to back of last molar

Length of the complete molar series

Length of the molar series, excluding the first premolar

Length of the molar series, exclnding the first two premolars

Length of the premolar series

Length of the true molar series

Breadth of second premolar

Thickness of second premolar

Breadth of third premolar

Thickness of third premolar ...

Breadth of fourth premolar

Thickness of fourth premolar

Breadth of first molar ".

Thickness of first molar

Bieadth of second molar

Thickness of second molar

Breadth of third molar . -

Tbickness of third molar

PaliBosyops
major.

Lines.
37
26
IG
14
92
90
82
72
38
53

7
13i

9
ICi

24
13i

Lines.

08
51

8
G
8a

13i

ICJ

22
12

Paliposyops
paludosus.

Lines.
32
23
13
lOi
?77

64
4GJ

8.i

5i
9

6:}

12i

9i
19
10

Some additional specimens, found by Dr. Corson iu the buttes of Dry
Creek Caflon, appear to belong to tlie larger Palaeosyops. These consist of
some upper tectli, comprising a canine, a second and last premolar, and the
second and third molars.

The latter are represented in Figs 10, 11, Plate XXIII, and they agree
in character witli the corresponding smaller teetli described nnder the head "
of Pu/cBO-si/ojys paludosus. They are but slightly worn at the summits of the
lobes of the crown, and the enamel is conspicnonsly wrinkled.

The last premolar, represented in Fig. 9, of the same plate, likewise agrees
with the corresponding tooth described umler the head of PalcBOstjops palu-
dosus, except that it is of larger size. The tooth is Init slightly worn, and
e.xhil^its a much less wrinkled condition of the enamel than the true molars.

The second premolar, represented in Fig. 8, resembles in form that of the
second series of specimens of upper molar teeth, described under the head of

I'lihvosijops paludo.'iu.s. It is larger, less worn, and has, comparatively with
the true molars, smooth enamel.

An upper canine tooth, i-epresented in Fig. 7, is of less size than that in
the facial specimen of PalceosyojJS paludosus^ the reverse of the condition in
lliis respect of the molar teeth. The canine tootii resembles, in its form an<l
proportions, the corresponding weapon of the bear. The crown is of mod-
erate length, and cnrved conical. It is provided with a subacute ridge in
front and behind, defining the smaller inner face from the outer one, and has
the base slightly thickened internally. The enamel is nearly smooth, and is
somewhat worn on the anterior face. The fang is considerably longer than
the crown, less curved, and is in some degree gibbous.

A lateral incisor, represented in Fig. 5, Plate XXIV, is a strong tooth,
somewhat resembling that of the tapir. The crown is conical, with the inntu-
and outer faces defined by ridges, with the base thickened in front, and u
strong basal ridge internally. The fang is about twice the length of i\\£,
crown, and is somewhat sigmoid.

The measurements of the upper teeth of PahEosyops major, in comparison
with those of P. paludosuSy are as follows :

Autero-posterior diameter of last upper molar . .

Transverse diameter of last upper molar

Autero-posterior diameter of secoud upper molar

Transverse diameter of second upper molar

Antero-posterior diameter of last premolar

Transverse diameter of last premolar '

Autero-posterior diameter of second premolar . . .

Transverse diameter of second premolar

Leugtli of crown of cauiue

Autero-posterior diameter of base of cauiue

Transverse diameter of base of canine

Diameter of fang of cauiue

Length of crown of lateral incisor

Diameter of base of crown of incisor

Diameter of fang of incisor

Palu'osyoiis,

Pahcosyops

major.

paluilosus.

Lines.

Zincs.

IGa

lOJ

12.i

7.i

A small collection of teeth belonging to the larger Palaeosyops was obtained
by Dr. Carter in a butte ten miles distant from Dry Ci'eek Canon. Amoiiir
llic specimens there is a scries of upper premolars, froin the second to the

7 G

last, inclusive, ir[)i-cs('iitctl in Fii^. 12, Plate XXIII. The crowns of the
teeth are worn, and also somewhat eroJeil, Init not to such an extent as tu
obscure their characters.

The last npper premolar agrees \\ ith that previously described and referred
to Palceosyops major, except that it is of more uniform width.

The third premolar is a reduced representative of that behind it, i)nt is also
pro])ortionately of less width transversely.

The second premolar is like the corresjujuding tooth above described and
referred to Palaosyops major, but is considerably nari'ower fore and aft.

A much worn upper true molar, partially broken away externally, is rather
smaller than the specimen of a second upper molar above described and
referred to PalcBosyops major. It sufficiently accords with it to be the first
of the series of true molars.

Another specimen consists of a mutilated canine, intermediate in size to
the more perfect one above described, and the larger one, contained in the
facial specimen described under the head oi' Pa/ausj/ops j)aludosi/s. The fimg
toward the extremity is more curved than in either of the other specimens.

An upper lateral incisor was about the size of the one previously described,
l)ut has a stouter fang. Its crown, Ijroken toward the point, is deeply \\orn
away internally.

Another incisor, a lower one, is represented in Fig. 15, Plate XXIII. It
has a short, conical crown, with a strong basal i-idge posteriorly.

The measurements of the specimens are as follows:

Liiu's.

Antero-posterior diameter of upper true molar, estimated 10

Transverse diameter of upper true molar 18

Antero-ijosterior diameter of upper last premolar S'}

Transverse diameter of upper last premolar 1-|

Anteroposterior diameter of upper third pi-einolar 8

Transverse diameter of upper tiiird premolar. 11':^

Autero-posterior diameter of upi)er second premolar 7

Transver.se diameter of upper second premolar , 8^

Length of fang of canine -^

Diameter of fang of canine 12

Length of fang of npper incisor 2-!

Diameter of fang of u[)per incisor 7i

Length of crown of knvvr incisor 0

Antero-posterior diameter of lower incisor 0

Transverse diameter of lower incisor ■ 5

An important and instructive specimen pertaining to /'^/Zews/yo^w /«(//o/- is
reiiresenfed in Fig. Iti, Plate XXIII, and Fig. 1, Plate XXIV. It consists

of a cranium, discovered by Dr. Carter in the hutles uf Dry Creek Canon.
The specimen was broken into many pieces, but tliese have been united so
as to give us a good idea of the shape and construction of tlie cranium. This
is of remarkable form, and exhibits more resemblance to that of a bear flian
to that of its nearer relative the tapir.

The forehead, as seen in the upper view of the cranium, Fig IG, Plab^
XXIII, forms a long triangle, with the apex prolonged backward and expanded
at the summit of the occiput. Its fore part more abruptly widens as it exten<ls
outwardly upon the conspicuous postorbital processes. Its surface from the
apex forward is strongly convex, but approaching the muzzle between tlie
position of the postorbital processes it becomes in the same direction con-
cave. Transversely it is nearly straight between the boundaries of the tem-
l»oral ibss;e, but is convex between the postorbital processes. The lalter
are strong and unusually prominent, trihedral, hook-like projections. Their
upper acute border forms the anterior extension of the temporal boundary
from the forehead. Their supra-orbital margin curves from the tiice Jiack-
ward and outward to the point. Their anterior or facial surface is depressed
or concave.

The postorbital process preserved in the specimen is broken at the end,
but is there so narrow as to make it appear that it did not meet an ascending
process from the malar l)one as to Ibrm a postorbital arch. The strongly
arched supra-orbital border is directed outward with a moderate backw ard
inclination, indicating a more forward direction for the orbit than in the tapir
and rhinoceros.

The short postorbital eminence of the malar bone in tlie facial sjiecimen
referred to Falatosyops paludosus, and represented in Fig. 51, Plate XVIII,
would also indicate that the orbits were oj^en behind in Palset)syops, notwith-
standing the great length of the postorbital process of the frontal in the
specimen under consideration.

The l)ase of the muzzle, or the face, between the position of the orbits is
broad and convex.

, Tiic specimen exhibits no evident traces of the sutural conjunctions of the
parietals, frontal, the maxillaries, and the nasals.

The cranial crest separating the temporal fossa; is exceedingly short com-
pared with that of the tapir. It is formed by the approach of the temporal
l)oundaries, which appear in this position as two ot)tusc ridges squeezed

52 •

tugethcf, and leaving between thcni a narrow groove extending from the tore-
head to a transverse concavity at the summit of" the occiput.

The temporal fossas are of huge proportions, and appear even to exceed those
of the greatest living carnivores, as the lion and the Bengal tiger. The zygo-
mata are as prominent as in these, but are proportionately of greater strength,
being both deeper and thicker. Excepting in their greater extension out-
wardly from the posterior root, as in the latter animals, in^ their sigmoid direc-
tion downward and forward they are more like those in the tapir. Their
outer surface is convex, and is directed obliquely upward.

The temporal surface at the side of the cranium, and extending on the
zygomatic root, forms a deep excavation or concavity slightly overhung by the
upper part of the temporal ridge. It exhibits a comparatively feeble swelling
aljout the position of the squamous suture, but much less conspicuous than that
in the tapir. The great hollow of the temporal surface is in striking contrast
with the sweUing of the corresponding surfiice in the great living carnivores,
and \yhile it is expressive of an equal if not greater extent of powerful muscles,
it is further expressive of a proportionate decrease in the capacity of the cra-
nium and therefore of a much smaller brain.

The cranium is constricted at the sides at the lower ])art of the temporal
fossse, just in advance of their middle, and the fore part, independent of tlnj
extension of tlie zygomatic roots, appears nearly as wide as tiic back part.

The squamosals are large, and reach half way up the temporal surface. A
conspicuous group of neuro-vascular foramina occupy their upper back part,
including the contiguous part of the parietals. The occiput is wider than
high, is strongly concave above, but at the lower part slopes backward to the
margin of the occipital foramen. Its sides below are bent forwarti, as in the
tapir, and the lateral borders above, as in the latter animal, are produced in
wing-like expansions. The basal angles of the occipital triangle arc formed
by comparatively short, wide processes, composed of the conjoined paramas-
toid and post-tympanic processes. These extend iToni within the position of
the occipital condyles and reach outwardly a considerable width beyond them,
but do not project much below the root of attachment of the condyles. The
occipital condyles ;;re of greater proportionate width but less depth than in
the tapir or the bear; and they project from the occipital surface backward
more than in either of those animals. The occipital foramen is transversely
oval.

The general plane of tlu! uceipul is intermediate in ils degree of inelinatidii
to that of the tapir and our large caruivores,, and is indeed nearly vertical.
The occipital condyles project posterior to the general surface, and thus form
tlie most pi-ominent portion of the occiput, whereas in the tapir, bear, and cats
the summit of the occiput is most prominent backward.

The articular surfaces of the condyles extend forward on the basi-oceipital,
and approach quite near each other, as in the bear.

A large vencnis foramen occupies the course of the occipi to-temporal suture,
about the center of the lateral plane of tlie occiput.

The auditory archway is high and narrow compared with that of the tapir.
It is widest above and has its sides converging inwardly.

The post-glenoid tubercle, compared with that in the tapir and ijcar, is very
thick and strong. It is broad and mammillary, and is directed obliquely out-
ward and projects downward below the post-tympanic process. The base of
the cranium is very broad compared with that of the tapir, and in this resi)cct
is more like that of the great carnivores.

The basi-occipital is broad and thick. It narrows forward from the posi-
tion of the paramastoid processes. Its sides are concave from before back-
ward, slope strongly from the upper edge toward each other, and are sepa-
rated by a median carina which expands behind and ends in front in a prom-
inence. The basi-sphcnoid, completely co-ossified with the basi-occipital,
appears as a narrowed extension of this, and is transversely convex.

Large vacant spaces, occupied with the matrix of the fossil, are situated
below the position of the petrosals. The tympanies are lost.

The glenoid articular surface is broad and nearly horizontal above, and
extends obliquely downward, outward, and backward on the robust post-
glenoid tubercle.

The anterior condyloid foramen is situated about three-fourths of an intdi
in advance of the occipital condyle.

The root of the pterygoid process is pierced with an ali-sphenoid canal, and
the oval foramen occupies a position just above it.

Measurements of the cranium are as follows:

Length of crauium from tbe C0Qca,vity at the summit of the occiput to a
line between the post-orbital processes, following- the curvature of the
forehead 9 inches.

Breadth acress the face, following the convexity between the ends of the

post-orbital processes S^ inches,

Distance between the orbits across the face above 0 inches.

Thickness of tlie short ciauiul crest seiKiratiiii;- the temporal l'oss;i' poste-
riorly 3 i"*^li

Breadth of temiioral foss;e from the occipital border to the end of the i)OSt-

orbital process 9 inches.

Vertical extent in advance of zygomatic root •. 5 inches.

lireadth of cranium outside of zygomata 11 inches.

Height of occiput . . 53 inclaes.

Breadth of occiput at post-tympanic processes (ii inches.

Breadth of cranium at ends of post-glenoid processes 8 inches.

Transverse diameter of occipital foramen ; . . 23 lines.

Vertical diameter of occipital foramen, estimated ■. IG lines.

Breadth at occipital condyles together 47 lines.

Depth of occipital condyles IS linos.

Breadth of occii)ital condyles 19 Hues.

Width of basi-occipital at anterior condyloid foramiua. 18 lines.

Width of basi-occipital at conjunction with basisphenoid 15 Hues.

Distauce between glenoid articular surfaces 51 lines.

An upper-jaw fragment, from the same individual as the cranium just
described, contains the last two molars, of wliicli the pemdtimatc one is re[)-
resented in Fig. 3, Plate XXIV. This tooth closely resembles the corre-
sponding one of the same species represented in Fig. 10, Plate XXIII, and
also that of Paloiosijops paludosus as represented in Figs. 3 to 5, Plate IV, and
Fig. 9, Plate V. The last molar, as fai* as it is preserved, likewise resembles
the corresponding tooth represented in the same places. The inner part of
the crown presents a single conical lobe.

The infVa-or])ital Ijorder forms a thick, obtusely rounded ledge projecting
obliquely forward on the face. In Palaosyops faludomH the corresponding
ridge presents an acute anterior edge defining it from the facial surface beneath.
The outer ])art of the thick infra-orbital ridge rises in a short, l)lunt, conical emi-
nence or postorbital process. The orbital floor is concavely depressed within
the prominent margin, and forms a long, triangular platform terminating
beiiind in the thick posterior boundary of the maxilla.

The measurements of the specimen are as follows:

Lines.

Space occupied by the last two molars 32

Breadth of second molar • 20

Width of second molar 20

Height of anterior orbital margin from the molars 20

Fragments of both sides of the lower jaw with all the teeth broken away,

except portions of the last molars, also accompany the preceding sjiecimens.

The best preserved fragment partially restored from the corresponding ]>or-

li(ni of the opposite side is represented in Fig. 4, Plate XXIV. It agrees in

i'onn niid pi'dpoiiioiis willi the same jxirlioii ol' \\\c jaw in Palceoxi/o/is pnUi-
(losus, excei)tiiig that the masseteric fossa- is nuicli deeper. The preser-
vation of the angle of the jaw, not retained in any of thi^ previous specimens of
Palaeosyops, permits the determination of its character. It presents a nearly
serai-circular border projecting moderately below ti)e base of the bone, and in
a less degree posteriorly. Toward the base it is somewhat bent inward.

The last molar, in a restored condition, of the natural size, is re|)resente<l
in Fig. 14, I'late XXIII, but, unfortunately, the artist has made its tliickness
in front proportionately too great.

The measurements of the specimen are as t()llows:

Palaiosyops
uuijor.

Paloeosyopa
liahulosus.

Distance from last molar to back border of jaw

Lilies.
01
■72
35
10
22
13

Livcfi.
4!)

Deptli from coiidvle to bottom of angle

I)(^i)tli of iaw bt^low fore nart of last uiolar . .

Tlii(!kiioss of i;iw bolow forp, i>a,rt of List iiiohir . . -

Tjveadtli of last molar tooth

Wkltb at fore part of last molar tooth

Width at middle part of last molar tooth

lOi

Fragments of another jaw similar to the above, and presenting the same
comparatively deep masseteric tbssa, were found by Dr. Corson at Grizzly
Buttes.

Fig. 2, Plate XXIV, represents a mutilated facial portion of a skull appar-
ently referable to PalcBosyops major. The specimen was found on one of the
buttes of the Bridger formation by a Shoshone Indian, and brought to Dr.
Carter, by whom it was presented to the writer. Though much distorted in
form, it gives us a fair idea of the shape and construction of a portion of the
skull of Palseosyops that we had not previously had the opportunity of ex-
amining. It is crushed in such a manner that the upper part of the face is
pressed downward and toward the right side, and the orbit has its roof
brought near to the floor, so that it looks as if it were closed behind l)y the
presence of a postorbital bridge.

The specimen shows that the form and construction of the face of Paloeo-
syops are very similar to what they are in Paleeotheiium. The upper part of
the face appears to have been directed in a moderately sigmoid course, nearly
horizontallv from the bottom of the convex forehead to the end of the muz-

zle. The n;i«ils are large, thick, and strong. Proportionately they exceed in
length those of the Pal«othere, the rhinoceros, and the tapir. If I mis-
take not a tiacture for a suture, their posterior extremity reaches as ftir as the
position of the fore part of the orbits, and their free extremity projects quite
as much as the jaws. They are strongly arched transversely and are mdre
abruptly rounded and thick at the lateral 'borders. They gradually narrow
tljrward and terminate in a blunt extremity, which is nearly straight but
rounded at the outer angles. Posteriorly, they include a deep and wide an-
gular notch, which receives a corresponding angular prolongation of the
fVontals.

The lateral nasal notch resembles that of the rhinoceros, Init is propor-
tinnately of greater depth, and in this respect also resembles that of the
Palseothere. Its exact extent cannot be determined on account of the mu-
tilated condition of the specimen. .

The upper jaw in its form and proportions is nearly like that of the Palaso-
there. It is of greater proportionate depth below the orbit, and exhibits a
greater swell at the border of the nasal notch, due to the greater size of the
canine teeth. The infra-orbital foramen is large, and is'situated over the
position of the last premolar. The hard palate is flat along the middle an-
teriorly. Its posterior part is destroyed in the specimen, so as to prevent
the determination of its extent.

The incisive foramina appear to be comparatively small and widely separated.
They appear also to be circular, and continuous with grooves descending for-
ward to the incisive alveoli.

The teeth form a series as unbroken nearly as in Anoplotherium. They
are all mutilated in the specimen, but the crown of the last premolar, and the
molars are sufficiently well preserved to exhibit the characteristics of Palseo-
syops as already described.

Measurements of the specimen, for the most part approximative on account

of its distorted condition, are as follows :

Length of jaw from back of last molar to front of incisive alveoli 9 inches.

Length of face from the anterior orbital margin to the end of the nose. . . 7 inches.

LcngtL of the nasals in the median line 5 J inches.

Breadth of the. nasals together at their middle 3^ inches.

Length of space occupied by the molar series Csjr inches.

Length of space occupied by the true molars 3^ inches.

r.readtli of last premolar ; 9 lines.

Width of last premolar , 12 lines.

Breadth of lirst molar .' _ . 14a liues.

Width of hrst molar 14j^, ijups.

Breadth of secoud molar Kj" ijucx.

Width of second molar k; lines.

Breadth of last molar 19j lines.

Width of last molar 18 liues.

Width Of palate betweeu canines 2S lines.

Width of canine alveoli 9 lines.

PALyEOSYOPS JUNIUS.

Dr. Carter recently sent the writer several small fragments of the rit^ht
side of a lower jaw, togetiier with a sketch of a larger fragment of the left
side, containing the last premolar and the succeeding molars. The s|)eci-
mens were obtained from the Bridger beds, and appear to indicate a small
species of Palasosyops, though it is not improbable that they pertain to a
small variety of P. paludosus.

The parts agree closely with the corresponding parts of the lower jaw and
teeth of the latter, except in size. They have been viewed as representatives
of a species with the name of Fal<eosyops Junius.

The measurements of the teeth in comparison with those of P. indudosus
are as follows :

Space occupied by the last premolar and molars

Space occupied by the molars >

Breadth of last premolar

Thickness of last premolar

Breadth of first molar

Breadth of second molar

Breadth of third molar

Thickness of third molar at middle

PiiiiEosyops

Palyosyops

JUUIUS.

paludosus.

Lilies.

Lines.

39i

■10

«i

12^

LIMNOHYUS.

This genus was originally named by Professor Marsh, in a communication
published in the American Journal of Science for August, 1872, and was
applied to Paleeosyops under the misapprehension that this genus had not
been distinguished by the possession of one or two cones to the inner part of
the crown of the last upper molar tooth. As it was as cleai-ly demonstrated
as the nature of the specimens would admit, that the last upper molars of
8 G

Palasosyops possessed l)iii a single cone to llic imier part of the crown, the
name subsequently proposed by Professor Marsli on account of this character-
istic was untenable. Under these circumstances, though I previously viewed
the difference as simply specific, I would adopt the generic nameof Limnohyus
lor those forms of Pakeosyops, as recognized by the general constitution of
the teeth, in which the last upper molars have two cones to the inner part of
the crown.

Fig. 13, Plate XXIII, represents an upper molar tooth, apparently the fii'st
of the series of true molars, resembling in form the corresponding teeth of
Palceosyops paludosus. Tlie enamel of the tooth is, however, comparatively
smooth, a condition which is clearly independent of its age, as the tooth is
but moderately worn. As a considerable degree of variation is observed in
the extent of wrinkling of the enamel of the teeth of Palceosyops imludosus,
independent of wearing, it is not improbable the specimen may pertain to
an individual variety of the same, though it prol)ably niay indicate anotiier
species.

The specimen was found by Dr. Corson in association with the large tusks
originally referred to Uintamastix atrox, described in a later chapter, and
represented in Figs. 1 to 3, Plate XXV.

Since wi-iting the description of the smooth, enameled molar tooth, Pro-
fessor Marsh, who has inspected the specimen, informs me that it pertains to
the same animal he has described under the name of Palaosyops laticeps,
(Am. Jour. Sc, Aug., 1872.) As this is stated to have four lobes to the
crown of the last upper molar, for reasons already given, it would belong to
the genus Limnohyus.

Fig. 8, Plate XXIV, represents the crown of an ujiper molar tooth, which
was found, together with some small fragments of other molars, both upper
and lower, by Dr. Corson on the buttes "of Dry Creek Cailon. The specimen
I supposed to belong to a small s])ecies of Pateosyops, and so referred it,
under the name of P. hiimUlfi, in a letter to the Academy, published in
its Proceedings for July 30, 1872. Under the impression that it was
perhaps the last tooth of the series, in view of the distinction suggested by
Professor Marsh between Palaeosyops and Limnohyus, I subsequently
ascribeil it to the latter. Professor Marsh informs me that he has a number
of specimens which lead him to regard the tooth as pertaining to the tempo-
rary series of Palaeosyops.

HYRACHYUS.

An extinct genus of odd-toed pachyderms, under the above name, was
originally inferred from specimens of fossils obtained during Professor Hay-
den's exploration in Wyoming, in 1870. One of the specimens, represented
in Fig. 11, Plate II, consists of the greater portion of a ramus of the lower
jaw, without teeth, found on Smith's Fork of Green River. The other speci-
men, represented in Fig 12, consists of a lower-jaw fragment, witli several
teetli, of a young animal, from Black's Fork of Green River.

Hyrachyus is closely related with the extinct tapiroid genus Lophiodon, the
remains of which belong to the early Tertiary formation of Europe. In a less
degree, also, it is related with the rhinoceros-like Hyracodon of the Mauvaises
Terres of White River, Dakota. Among living animals, it is most nearly
allied to the tapir, and more remotely with the rhinoceros.

The dental series of the true Lophiodon, if the L. isselense of Issel,
France, be viewed as the type of the genus, or of Tapirotherium, as it had
been previously named by De Blain.'ille, consists of three iucisors, a canine,
three premolars, and three molars. The living tapir at maturity has one pre-
molar more to the upper series.

In one species of Hyrachyus at maturity there are four premolars to the
series above and below, as in Hyracodon. Apparently, in a second species
there are four premolars in the upper series, and three in the lower, as in the
tapir.

The last lower molar of Lophiodon has a trilobate crown. In Hyrachyus,
as in the tapir, it has a bilobed crown.

The crowns of the lower molars are intermediate in character with those
of Lophiodon and Hyracodon.

The upper molars of Hyrachyus closely resemble those of Lophiodon. In
both genera the upper back two premolars have a single lobe to the inner
part of the crown representing the inner pair of lobes of the crowns of the
succeeding molars in a connate condition. In Lophiodon a ridge proceeds
from the inner lobe of the crown of the premolars mentioned to the antero-
external lobe. In Hyrachyus, in the corresponding teeth, a pair o£ ridges
proceed from the inner lobe of the crown to both the outer lobes.

The lower jaw of Hyrachyus has nearly the form and construction of that
of the tapir.

Hyrachyus agrarius.

This species, originally inJicatcd aiul named from tlie specimen repre-
sented in Fig. 11, Plate II, consisting of a ramus of the lower jaw without
teeth, we have now the opportunity of illustrating by many well-preserved
and more characteristic specimens. Most of these were collected by Dr. J.
Van A. Carter, during the last summer, on Henry's Fork of Green River,
near Lodge-Pole Trail, at Bridger Butte, and other localities in the vicinity of
Fort Bridger, Wyoming. A few others were detained by Dr. Joseph K.
Corson, from Grizzly Buttes, Wyoming.

The specimen represented in Fig. 12, Plate II, being one of those upon
whicli the genus Hyrachyus was originally proposed, was referred to another
species from the former one, with the name of Hyrachyus agrestis. This I now
regard as of the same species. The specimen, a lower-jaw fragment, belonged
to a young animal, which still retained its temporary teeth. Of these, the
fossil contains the first premolar, the fangs of the succeeding two, and the
molar tooth. Behind this the first molar of the permanent series is inclosed
within the jaw.

Professor Marsh has described remains apparently of the same animal
under the name of Lophiodon Bairdianus. The specimens, which he observes
are among the most common of the mammalian fossils of the Wyoming Ter-
tiary, were found at various localities near Fort Bridger, and also on the
White River, in Eastern Utah.

The dental series of Hijrachyus ngrar'ms, in the mature condition, consists
of three incisors, a canine, four premolars, and three molars, in both jaws.

A well-preserved series of upper molar teeth, considerably worn, is repre-
sented in Figs. 9 and 10, Plate IV, from a specimen discovered by Dr. Car-
ter near Lodge-Pole Trail, about eleven miles from Fort Bridger. Fig. 11,
of the same plate, represents an upper second molar, which was obtained by
Dr. Carter on Henry's Fork of Green River.

Of the upper molars, or true molars, the middle one is the largest, and the
others are nearly equal in size. Four principal lobes enter into the constitu-
tion of iheir crown, which is inclosed by a basal ridge, except externally, and
at the. most prominent portion of the inner lobes internally. Of the outer
lobes, which are conjoined, the posterior is the wider and is pyramidal; the
anterior is the more prominent externally and is conical. Tliis is also strength-
ened in front by a large conical buttress continuous with the comparatively

wide anterior l)asal ridge of the crown. In tlic last molar the jiosterior of
the outer lol>cs is proportionately less well developed than in the molars in
advance. The inner lobes of the crown are conical internally, and are extended
obliquely outward so as to form ridges continuous with the fore part of the
outer lobes. The oblique valley separating the inner lobes is closed exter-
nally by the conjunction of the outer lobes. A wide, angular recess occupies
the interval of the posterior lobes of the crown and the posterior basal ridge.

In the unworn or moderately worn condition of the molars, as seen in Fig. 11,
Plate IV, a narrow but conspicuous ridge or fold is observed projecting from
the antero-external lobe into the median valley of the ci-own. In the
worn condition of the molars, as seen in Fig. 10, c to g, they exhibit a
Iract of exposed dentine extending along the summits of the outer lol)es
including the abutment in front, and prolonged inw^ardly in two pouch-like
extensions upon the summits of the inner lobes.

The upper premolars not only exhibit from behind forward a successive
diminution in size, but also a reduction to greater simplicity. The latter con-
dition is induced through connation and disappearance of constituent elements
as they are observed to exist in the back teeth. Thus if we compare the
back two premolars, Fig. 10, c, d, with the molars behind, it will appear tliat
the most striking difference is due to the connation internally of the inner
lobes. From this arrangement the premolars appear to have a single loi>e to
the inner part of the crown, from which a pair of ridges proceed to join the
outer lobes. A central pit represents the median valley opening internally in
the crown of the molars. The basal ridge extends around the inner part of
the crown.

The abutment so conspicuous at the antero-external angle of Ihc crown of
the molars is successively reduced forward in the premolars and disappears in
the anterior two.

In the crown of the second premolar. Fig. 10, h, the outer lol^es are more
connate than in those behind, and the inner lobe appears more isolated from
the absence of the intervening ridges.

The crown of the first premolar, Fig. 10, a, about half the size of^that of
the tooth behind, is conoidal with an oval base. For the most part it is
homologous with the outer lobes of the other premolars in a completely con-
nate condition. A small offset internally is a ruiliment of llie inner lobe of
Ihe succeeding premolar.

A hiisal ridge exists at the outer back part of the crown of tlie seconcl pre-
molar, and, less produced, exists in the same position in the third. No ridge
occupies the inner prominence of tlie inner lobe of the second premolar.

A specimen of an upper left last premolar, found at Grizzly Buttes by Dr.
Corson, is represented in Fig. 12, Plate IV. It is larger than in the entire series
of Fig. 10 and is less worn. It exhibits a basal ridge externally interrupted
at the middle ; and internally the ridge is also interrupted or nearly obsolete
at the middle. The posterior ridge or fold between the inner and postero-
external lobes, though smaller, is more defined from the lobes than the ante-
rior I'idge. The latter appears rather as a pi'olongation of the inner lobe to
the fore jiart of the base of the antero-external lobe. The posterior ridge has
the appearance of an introduced piece defined from the lobes by consti'ictions
or grooves. The arrangement is badly represented by the artist; nor is it
obvious if it existed iii the corresponding more worn tooth of the series (jf
Fig. 10.

In a much mutilated specimen, obtained by Dr. Corson at Grizzly Buttes,
containing the remains of the last two premolars and succeeding two premo-
lars, the basal ridge is better developed at the inner part of the crown than
in any of the preceding. The last premolar exhibits the same condition of
the posterior ridge intervening to the internal and postero-external lobes of
the crown as that described in the isolated tooth. The same tooth, barely
worn, exhibits the summit of the inner lobe of the crown slightly divided into
two points, so that it presents a less degree of connation than in the preceding
specimens.

The upper molars and premolars, except the first one, are inserted by three
fangs, of which the inner one is a connate pair; the connation being most
complete in the premolars. The first premolar has two fangs. The space
occupied by the upper molar series is about 3| inches.

Fig. 13, Plate IV, represents a specimen, found by Dr. Carter, in company
with the upper molar teeth of Figs. 9 and 10, and evidently pertaining to the
same individual. The specimen consists of the anterior extremity of the
lower jaw, retaining the incisive alveoli, the canines, and on one side the four
premolars. A view of the triturating surfaces of the latter is given in Fig.
14. Figs. 15 and 16 represent a second molar, and Fig. 18 an incisor from
(he same individual.

Fig 25, Plate XX, was drawn from a specimen consisting of the greater

part, of a lower jaw, including both rami, obtained l)y Dr. Carter, at Bridgcr
Butte, seven miles west of Fort Bridger. The left ramus contains the pos-
terior three premolars and the succeeding two molars, of which a view of tiic
triturating surfaces is given in Fig. 26.

The lower molars, including the last one, in H)/rachyus agrarius have all
bi-lobed crowns. These are oblong square, and bounded by a basal ridge in
Iront, behind, and in a more or less interrupted condition externally. Tlie
constituent lobes have somewhat curved rectangular summits as in Hyracodon
and rhinoceros. The summit of the anterior lobe curves forward and inward,
and becomes continuous with the basal ridge of the fore jiart of the crown.
As the acute summits are worn, tracts of dentine become exposed
crossing the teeth. In the progress of attrition the expanding dentinal tracts
extend in an irregular L-like manner,- and finally the contiguous tracts of each
tooth become continuous, as in rhinoceros at the same stage of wear.

The crowns of the premolars present the same essential constitution as
those of the molars, with the constituent lobes, successively, from behind
forward, becoming more reduced or rudimental. The posterior lobe l>ecomes
proportionately more reduced than the anterior, and in the first premolar has
disappeared.

The crown of the last premolar resembles those of the molars, with the
])osterior lobe proportionately more reduced than the anterior one.

The crown of the third premolar, in the speciinen represented in Fig. 25,
Plate XX, has the same form as in the last premolar, and is simply reduced
in size. In the specimen represented in Fig. 13, Plate IV, the tooth looks
ditferent, from the obfique ridge or summit of the anterior lobe of the crown
as existing in the former, being contracted in this into a conical and some-
what more elevated point. This gives such a remarkable diilerence to these
teeth in the two specimens, that, had they been tbund isolated, without a
knowledge of their collocation, they would have been attributed to dilferent
genera of animals.

The anterior two premolars have an oval crown elevated into a median
conical point and presenting offsets behind and in front, in which may be
detected the rudiments of the posterior lobe and anterior extension of the
anterior lobe of the better developed crowns of the teeth behind.

All the lower premolars, as well as the molars, are inserted by a pair of
fangs. The space occupied l)y the lower molar series in several specimens
ranges from 3 inches and .'i lines io o% inches.

The inferior canine teeth are quite like those of the tapir in appearance.
They curve upward and forward, with a slight inclination outward. The
crown is laterally compressed conical, subacute in front and behind, but worn
in both these positions in the specimen under examination.

The upper canines are unknown, unless the specimen represented in Fig.
17, Plate IV, is one. This vvas found at Grizzly Buttes by Dr. Corson, in
association with some upper premolars of Hyrachyus ; all of which look as if
they had belonged to the same individual. The crown of this Sjiecimen of
an upper canine is short, and worn off to a considerable extent at its fore
part. It is compressed conical, and lias the inner and outer surfaces defined
l)y an acute ridge posteriorly. The fang is double the length of the crown,
and is laterally compressed.

The incisor tooth, represented in Fig. 18, appears to be the second of
the series of the lower jaw. It resembles the corresponding tooth of the
tapir. Its chisel-like crown is worn off at the cutting edge.

No characteristic portions of the upper jaw of Hyrachyus have come under
our notice. In one specimen tire infra-orbital foramen is observed to occupy
a position above the third premolar.

The lower jaw resembles, in its form and proportions, that of the Hyraco-
don and the tapir. The anterior extremity, in the construction of the chin,
the contraction between the position of the canines and molar series, and
other features, repeats the condition observed in the tapir. A similar wide
hiatus separates the canines from the molar teeth. The free border of the
hiatus, upward of an inch in length, is concave fore and aft, and acute.

The body of the lower jaw is less robust or thick, in relation with its
depth, than in the tapir. It is also less convex externally, and at the
base fore and aft. The outer surface, in comparison, appears quite
vertical.

The ascending portion of the ramus rises vertically at its fore border, and
is deeply impressed on the outer surface just back of the latter.

The condyle projects less externally and more posteriorly than in the tapir.
Its articular surface is more flat, and in a less degree inclined inwardly.

In the specimen represented in Fig. 13, Plate IV, five small mental
foramina are observed, in a row extending from the position of the third pre-
molar to thtit of the canine tooth. In the specimen represented in Fig. 25, Plate
XX, a large mental foramen i.s situated below the intervul of the third and

fourth premolars; and in advance of tliis several small ones exist. In llie
specimen represented in Fig. 11, Plate II, the mental foramen is situated
below the first premolar.

Measurements from several specimens of lower jaws of Hyrachyus agrarius
are as follows :

Leugth of space occupied by the molar teeth

Distance from incisive alveoli to first premolar

Length of hiatus between canine and first premolar

Depth of jaw below last molar

Depth of jaw below last i>remolar

Breadth of jaw at caniue alveoli

Breadth of jaw below hiatus

Length of symphysis

LiDes. Liues

25
13

14
12

42
24
13
IS
15
13
10.J

Liucs.

20
10

Measurements of upper molar teeth are as follows:

luchcs. Lines.

Length of the entire upper molar series 3 9

Length of series of premolars • 1 8.1-

Length of series of molars 2 1 ',

Diameter
Diameter
Diameter
Diameter
Diameter
Diameter
Diameter

of first premolar . . ,
of second premolar
of third premolar . .
of fourth premolar .

of first molar

of second molar . . .
of third molar

Comparative measurements of two upper last premolars are as follows :

Lines.

Fore and aft diameter in both 7

Transverse diameter in one 8^

III the other 9

Measurements of lower molar teeth are as follows :

Length of the entii'e lower molar series .

Length of series of premolars.
Length of series of molars . . . .

Lines.

42
19
24

Lines.

44
20

Foro aud aft.

Diameter of first premolar . .
Diameter of second premolar
Diameter of third premolar.
Diameter of fourth premolar

Diameter of first molar

Diameter of second molar . . .
Diameter of third molar. . . .

Lines.

G
Gh

Lines.

5^
8i

Transverse.

IjUK'S.

2.i

Tj'uiv

2i-

Hijrackyus agrari>(.s was al:)uut the size of the coininoii collared peccary,
Dicotyles torquatus.

HYRACHYUfcj liXIMIUS.

A .supposed larger species of Hyrachyus lluui H. dgrarius is interred IVoin
several specimens, consisting of small fragments of a lower jaw with a tooth
and portions of others. These were obtained by Dr. Carter on Henry's Fork
of Green River.

The best and most cliaraeteristic specimen is represented in Figs. 19, 20,
Plate IV, consisting of a lower-jaw fragment containing the last premolar and
portion of the first molar much worn. Both the teeth and the jaw agree in
form with the corresponding parts in Hyrachyus agrarius and differ only in
size. The specimen also agrees with the" corresponding ])art of Lophiodon
sufficiently to belong to the same genus, so that until more amjile material is
discovered it must remain uncertain whether it really i)ertains to Hyrachyus.

Comparative measurements are as follows :

H. oxiiiiius. H. ;nrrariii.s.

Lines.

Depth of jaw at last premolar

Thickness of jaw at last premolar

Diameter fore and aft of last premolar.
Diameter transversely of last premolar

Diameter trausversly of first molar

Diameter transversely of second molar.

".s.

Lii

r.s.

5.>

•

Figs. 9, 10, Plate XXVl, represent a tooth recently obtained by Dr. Cai^-
tcr on the buttes of Dry Creek. It would apjiear, from its proportions, to l)e
(lii^lcfl lower ])eiinltimate molar of //y)Y?''////WA- czimiu^. It is a nearly un-

fi7

worn and perfect specimen, and agrees in its anatomical characters with the
corresponding tooth of H. agrarlus. The crown measures an inch antero-
jiosteriorly and 7^ lines transversely.

The specimens above described indicate an animal about tlie size of the
common American tapir.

HVRACHYUS MODESTUS.

Under the impression that teeth of like form with those of Hyrachyits
agrarius, from the Bridger Tertiary formation, pertain to the same genns, I
now view the tooth represented in Fig. 13, Plate II, which I previously
referred to Lopkiodon modestus, as belonging to Hyrachyus. The specimen
was obtained during Professor Hayden's exploration of 1870, on Smith's Fork
of Green River, near Fort Bridger.

The tooth is a first or second up])er molar, and differs in size and propor-
tion from the corresponding teeth of Hyrachyus agrarius sufficiently to indi-
cate a smaller species. The only other diflerence observable, one, however,
which may prove not to be constant in additional specimens, is in the internal
surface of the antero-internal lobe of the crown, being strongly wrinkled in-
stead of being elevated in a single conspicuous fold as in H. agrarius.

The comjiarative measurements of the specimen are as follows:

H. agrarius.

Lilies.

Diameter fore and aft of second upper molar 7 9

Diameter transversely of second upper molar Of 10

Hyrachyus modestus was about a third less in size than H. agrarius.

Hyrachyus nanus.

Portions of two lower jaws I have referred to a small species of Hyrachyus
with the above name. One of the specimens was obtained at Lodge-Pole
Trail, by Dr. Carter; the other, represented in Fig. 14, Plate II, and Fig. 42,
Plate VI, was found at Grizzly Buttes, by Dr. Corson.

In both specimens, which belonged to animals at maturity but not advanced
in life, the number of teeth in the molar series is six, or one less than in
Hyrachyus, and the same number as in Lojihiodon and the tapir. The last
molar, however, has a bilobed crown as in the latter, ))ul the premolars, in

ihcir less degree of (Icvelopinent in comparison wilh the molars, are more
like those of Lophiodon.

The suppression of an anterior premolar may jierhaps he regarded as a less
important generic character than the others which have been indicated as
separating Hyrachyus from Lophiodon and Tapirus. Under the circum-
stances, notwithstanding the reduction in the number of premolars, I view
the two jaw-specimens above indicated as pertaining to Hyrachyus.

Professor Marsh has described several specimens, from Grizzly Buttes,
under the name of hopModon nanus, which I suspect to belong to the same
animal as the lower-jaw fragments above indicated. Pie observes that the
most characteristic of the specimens is a right upper jaw containing a series
of four premolars and three molars. If, then, this really, belongs to the same
animal, it would give with the lower-jaw specimens, as the formula of the
molar series, seven teeth above and six below, as in the tapir. The upper
]u-cmolars, however, jiresent a greater amount of difference from the molars
than in the latter, the difference being mainly diic to a less degree of develop-
ment of the premolars and in the connation of the inner lobes of their
crowns.

The molar teeth and the portion of the jaw containing them are almost repe-
titions of form of the corresponding parts in Hyrachyus agrarius. The men-
tal foramen is situated below the first premolar. Hyrachyus nanus was
about half the size of //. agrarius.

Measurements from two lower-jaw specimens areas follows:

Space occupied by the complete series of molar teeth 2 .inches.

Space occupied by the premolars 93 lines.

Space occupied by the molars 14 lines.

Depth of jaw below last premolar 10 lines.

Diameter of llrst premolar

Diameter of second premolar.

Diameter of last premolar

Diameter of fir.st molar

Diameter of second molar . . . .
Diameter of last molar.

Fore and

nil.

Transverse.

Lines.

-h

4.1

Fig. 11, Plate XXVI, represents the greater part of the right ramus of
the lower jaw of Hyrachyus nanus, which I found, together with a fra'^mcnt

oC tlic opposite side and several other bones ot the skeleton, near the Lodge-
Pole Trail, crossing Dr}' Creek Valley. The specimen was found in part ex-
posed and partially imbedded in the indurated clay of a bntte, in company
with quite a profusion of well-preserved shells of Helix tvi/omingensis.

The jaw resembles in its form that of Hyrachyus agrarius, and also that
of the recent tapir. It contained a series of six molars, of which it retains
the back four.. The molars are separated by a wide hiatus from a continuous
arch of alveoli, for the accommodation of the incisors and canines, which corres-
pond in number with those of the tapir.

The depth of the jaw is rather less than in the fragments prciviously
described, while the dimensions of the molar series is nearly the same. The
measurements of the specimen are as Ibllows :

Lines.

Length of space from incisive alveoli to back of last molar 42

Leugtli of space occupied by f lie molar scries 24

Length of space occupied, by the true molars 14i

Autero posterior diameter of last molar 41

Length of symphysis ... IG

Length of hiatus in advance of molars 13

Depth of jaw below uiolars 9J

An upper-jaw fragment, recently sent to me by Dr. Carter, I suppose to
pertain to Hyrachyus iianiis. It contains the fangs of the anterior three
premolars, and the entire last one, which is represented in Figs. 21, 22, Plate
XXVII, magnified two diameters. This premolar resembles the corresponding
tooth o{ H. agrarius, but the ridge in the latter, w^hich represents the postero-
internal lobe in the true molars, is reduced to the smallest rudiment.

The space occupied by the four premolars measures 11^ lines. The
' breadth of the last premolar is 3.2 lines ; the width transversely is 4 lines.

LOPHIOTHERIUM.

LOPHIOTHERIUM SYLVATICUM.

The genus Lophiotherium was proposed by Gervais, from some fragments
of several lower jaws with molar teeth, which were found in association with
remains of true Palseotheria, in a formation of France which he regards as
belonging to the upper Eocene Tertiary. The genus is viewed as a tapiroid
pachyderm closely allied to Lophiodon, though the molar teeth appear very
unlike those of the latter.

Daring Professor Ilayden's exploration of 1870, a specimen was found on

Henry's Forkof Green River, which appears to pertain to a species oi'Lophiothe-
rium. The specimen, represented in Fig. 33, Plate VI, consists of a lower-
jaw fragment containing the last premolar and the first and last true molars
— the crown of the intervening true molar having been lost. The teeth
appear closely to resemble in form and constitution those of LophiotherUan
cei-vulum, as represented in Plate II of Gervais's Zoologie et PaUontologie
franQaises. The only apparent difference, which, nevertheless, is an important
generic one, if it really exists, is the division of the summit of the antero-
internal lobe of the crown of the teeth into two points in the American fossil.

The anterior teeth, Fig. 34, of the latter have oblong quadrate crowns,
slightly narrower at the fore part and otherwise alike in form. They are
quadrilobate, tlie lol^es being tri-laterally pyramidal and connate at base.

The last molar. Fig. 35, is prolonged behind in the manner so common in allied
animals of the same order. This prolongation is mainly due to the addition of
a fifth lobe to the crown, which is narrowed posteriorly in the reverse direc-
tion to the teeth in advance.

A strong basal ridge incloses the crowns of the teeth, excepting internally.
In the last molar it is less well developed and does not exist posteriorly. The
constituent lobes of the crowns are nearly of uniform size. The antero-in-
ternal lobe, as before intimated, has its summit divided into two points. The
division extends so short a distance that it w<nild be early obliterated from
the wearing of the teeth in the trituration of the food. It is hardly percepti-
ble, even in the unworn condition in the last molar, and in the specimen is
most distinct in the first true molar. As a character, it may l)e inferred to be
most obvious in the anterior two true molars, and less so in the premolars of
like_form and in the last true molar.

The postero-internal lobe of the crowns has a simple pointed summit. The
inner lobes have the crescentoid summit declining from a central point in-
wardly, so common in the corresponding teeth of allied animals. The fore
arm of the summit of the antero-ext'ernal lobe is a thick ridge curving to the
base of the antero-internal lobe in front. The back arm is a short ridge
directed inwardly to the anterior division of the summit of the antero-internal
lobe. The fore arm of the summit of the postero-exteinal lobe reaches the
middle of the antero-internal lobe. The back arm joins the posterior basal
ridge, proiUicing an elevated point at its middle. From the inner side of the

same lul)e a tliinl but less conspicuous ridge extends directly to the loI)e
within.

In the last molar the fifth lobe has a crescentoid summit declining from a
median point. The outer arm of the summit joins the contiguous arm of tlie
lobe in advance, and the inner arm joins the base of the postero-internal lobe.

The minutely detailed description of these teeth, and the same may be
said of those of other fossils, is essential to the distinction of generic characters.

From the back molars of Lophiodon, those of Lophiotherium especially
differ in the distinction of four instead of two lobes to the crown : though the
two lobes in the teeth of Lophiodon and Tapirus represent the four of Lo-
phiotherium in a connate condition.

The jaw-fragment of the fossil referred to Lophiotherium srjlvatician pre-
sents nothing peculiar. The outer vertical surface is slightly convex, and the
base fore and aft is also moderately convex.

The measurements of the fossil are as follows .

Liucs.

Depth of lower jaw below middle of last premolar 5;|

Depth of lower jaw below middle of last true molar '- Gi

Anteroposterior diameter of last premolar - 3.^

Autero-posterior diameter of first true molar 3^

Autero-posterior diameter of second true molar 3iJ

Autero-posterior diameter of last true molar 5^

Transverse diameter of last premolar -'i

Transverse diameter of trne molars 2J

Should the duplication of the summit of the antero-internal lobe of the

crown of tiie lower back molars not be a character present in the Lopliio-

therimn cervulum of France, it would probably be a concomitant of other

characters in the upper teeth, now unknown to us, which would distinguish

the American animal as generically distinct from Lophiotherium.

. In the American Journal of Science for 1871. Professor Marsh notices

some remains, from Grizzly Buttes, which be attributes to a species about

two-lhirds the size of the fcjrmer, and names it Lojjhiotherium BuUardi.

TROGOSUS.

Trogosus castoridens.

One of the most curious of the extinct mammals of the Bridger Tertiary
fauna is an odd-toed pachyderm about the size of the larger living peccary,
which, with the usual complement of molar teeth, was apparently devoid of
canines, and was provided with a large pair of incisors like those ol' rodents.

The singular character of the aiiunal was first recognized in a fossil specimen;
consisting of a mutilated lower jaw, discovered by Dr. Carter in the vicinity
of Fort Bridger, and sent to the writer in the spring of 1871. The specimen,
represented in Figs. 1 to 3, Plate V, besides the two large incisors, contains the
remains of most of the molar teeth, but none in an entire condition. The
best preserved is the second molar of the left side, and this is so much worn
as to have the distinctive features of its triturating surfiice, as seen in Fig. 2,
completely obliterated.

The specimen was originally described in the proceedings of the Academy
of Natural Sciences in May, lb71, and from its peculiarities the animal to
which it belonged was named Trogosus castoridens, or the beaver-toothed
gnawing hog. Professor Marsh had previously described an isolated tooth,
of the same animal, from Grizzly Buttes, which he referred to a species of
Palseosyops with the name of P. minor. From the description, I supposed it
not to difler from P. j)aludosus. An examination of the specimen has satis-
fied me that it belonged to the*same animal as the jaw referred to Trogosus.

The isolated tooth belonged to a younger animal, and is not so worn as to
have the characteristic arrangement of its masticating surface destroyed. On
seeing it I was struck with its resemblance to anotlier isolated molar tooth
wliicli I had formerly described under the name Anchipjjodus riparius. This
tooth was discovered by Dr. Knieskern in a Tertiary formation, supposed to
be of Eocene age, in Monmouth County, New Jersey. It was given to Mr.
T. Conrad, by whom it was ]5resented to the Academy of Natural Sciences
of Philadelphia. The same formation has yielded the remains of a peccary,
an Elotherium, and a rhinoceros.

A comparison of the tooth of the New Jersey Anchippodus with the cor-
responding one in the jaw-specimen and with liie isolated molar, would appear
to indicate that the Wyoming fossils belong to the same genus, and indeed
the teeth are sufficiently alike in form and size to pertaiji to the same species.
Should further discovery prove this to be the case, it would, perhaps, indi-
cate the contemporaneous character of the Bridger Tertiary foi-mation of
■Wyoming and that of Monmouth County, New Jersey. The New Jersey
fossil, in its general appearance of color and condition, so closely resembles
the Wyoming fossils that it would readily pass for one of them.

It is by no means positive that Trogosus and. Anchippodus are the same,

fur we have examples enough ul' different genera having the lower molars
alike, while the upper ones and the premolars are unlike.

The jaw of Trogosus retains evidences of the existence of six molar teeth,
and there may have been another small premolar, but this cannot be ascer-
tained from the mutilated condition of the specimen. The first of the series
of six molar teeth approached so close upon the lai-ge incisor as to leave but
a small interval for the introduction of other teeth.

The best preserved tooth of the molar sei'ies, the second molar, presents a
bilobed crown, in which the anterior lobe is the longer or least worn. The
triturating surface, represented in Fig. 2, Plate V, exhibits a wide tract of
exposed dentine with a yoke-like outline of enamel. Its fore and aft meas-
urement is 9J lines. The thickness of the anterior lobe at base is 8 lines.

In the less worn specimen of the corresponding tooth described by Profes-
sor Marsh, he gives the antero-posterior diameter as 10 lines; the transverse
diameter at the summit of the lobes of the crown as 5 and 5J lines wide.

The constitution of the lower molars of Anchippodus is apparently the
same as in Trogosus, as observed in the New Jersey tooth represented in
Figs. 45, 46, Plate XXX, of " The Extinct Mammalian Fauna of Dakota," &c.
Fi-om this it will be seen the crown is composed very nearly on the same
plan as that of the corresponding teeth in Anchitherium, Palseotherium, &c.
It is composed of a fore and aft pair of lobes with crescentoid summits,
convex externally and with a recess internally. The size of the tooth is the
same as that retained in the jaw-specimen above described. The fangs of
the last molar in the lower jaw indicate a trilobed ci'own,*as in Anchitherium,
Pateothferium, &c. The premolars, so far as can be ascertained by their
remains in the jaw, are inserted by two fangs. Canines most probably do
not exist in Trogosus, their absence being fully compensated by the large
incisors.

The incisor teeth on both sides together are iour in number; but while
the lateral ones are developed to the proportions of those of rodents, the
intermediate pair were quite small. The latter are lost from the specimen,
leaving the alveoli occupied by matrix. The space they occupied was about
the fourth of an incli from side to side.

The large lateral incisors are wonderi'ully like the incisors of rodents, not
only in form, position, and structure, but they were also alike in their perpet-
IOg

uiil mode of growth. Tliey do not extend so far hack within the jaw as in
most rodents, and in this respect are more like those in the rabbits, or, as in
tlieir nearer relatives, the peccary and hog. They extend beneath the pre-
molars, but the bottom of the alveolus does not reach the position of the first
molar.

The incisors are convex in front, and not flat, as usual in rodents. The
anterior convexity is invested with thick enamel longitudinally striated, the
striiB being wrinkled. Externally the edge of the enamel appears proportion-
ately more prominent than in rodents ; that is to say, it projects more above
the level of the contiguous exposed dentine. In transverse section the incisors
are ovoid, with the narrow extremity behind. The fore and aft diameter of
the section is 10 lines ; the transverse diameter at the edges of the enamel
layer is 6 J lines. The anterior convexity covered with enamel is 4 lines ;
the posterior convexity is J an inch.

The cutting edges of the incisors are broken, but the extremities of the
teeth are sufficiently well preserved to exhibit the manner of wearing. They
were not only worn in a sloping manner backward, as in rodents, but also
externally, so that it appears the upper incisors were more divergent than the
lower ones, and held a position related to them more like the condition
observed in the peccarj'.

The rami of the jaw, as usual in pachyderms, are completely co-ossified.
The. symphysis is remarkably strong and deeji, and in the median line is
nearly 3 inches in length. The rami just back of the symphysis are nearly
an inch thick. The chin forms a long, broad slope, defined at the sides by
the pronnnences of the large incisor alveoli, curving from the base of the
jaw ])arallel with each other upward and forward. The chin resembles that
of the peccary or rhinoceros, but is more convergent, as in the beaver.
Approaching the exit of the large incisors from their alveoli the intermediate
space is deeply grooved, as represented in Fig. 3.

The body of the ramus is short, deep, and thick. Its outer surfixce is ver-
tically convex. The base is thick and convex fore and aft as well as trans-
versely.

The masseteric fossa is deep, and extends downward to about the middle
line of the bodj^ of the ramus. Two mental foramina on one side, and tliree
on the other, occupy a position in advance of that of the last premolar.

75
Measurements taken from the lower-jaw specimen are as lollows :

Inches. Lines.

Distauce from iucisive alveoli to back of last molar i 10

Space occnpied by the molar teeth, estimated . .' 4 0

Space occupied by the true molars 2 7

Fore and aft diameter of last molar 1 I

Depth of jaw at second molar 1 G

Thickness of jaw below second molar 0 10

Estimated length of lateral incisors " 3 3

Depth of symphysis following its slope li 10

Trogosus vetulus.

An apparent smaller species of Trogosus is indicated b}^ the fragment of an
incisor tooth, represented in Fig. 43, Plate VI. The specimen was discov-
ered by Dr. Carter in the vicinity of Fort Bridger, and sent to the writer last
summer. It consists of the exserted portion of the tooth, and agrees in form
and proportions with the corresponding portion of the incisors in the jaw-
specimen above described. The enamel is smoother, but invests the tooth to
the same relative extent. The antero-posterior diameter of the tooth lias
been about 8 lines ; the transverse diameter 4 lines.

HYOPSODUS.

Hyopsodus paulus.

One of the smallest of pachyderms, referred to a genus and species above
named, is established on many specimens, chiefly consisting of portions of
lower jaws with teeth, (Figs. 1 to 9. Plate VI.) It was originally indicated,
fi'om a lower-jaw fragment with teeth (Figs. 1, 2) of an old animal, discov-
ered by Professor Playden, in 1870, in the vicinity of Fort Bridger, Wyo-
ming. Since then the writer has received a number of more characteristic
specimens, obtained l)y Dr. J. Van A. Carter and Dr. Joseph K. Corson, at
Grizzly Buttes, Henry's Fork of Green River, Lodge-Pole Trail, and other
localities in the neighborhood of Fort Bridger, Wyoming.

The animal was rather less in size than the Ajjhelotherium Duvernoyi of
Gervais, the remains of which were found in the gypsum quarries of Paris,
France. It also appears to have been allied to this, as indicated by the num-
ber, relation, and constitution of the teeth. Both Aphelotherium and Hyop-
sodus possessed unbroken arches of teeth to the jaws, as in the Anoplothe-
rium, whose remains are found in association with those. of the first-named

genus.

The iminber of teetli in Hyopsodiis appears to be three incisors, a canine,
and seven molars to the series on each side of both jaws.

Neither incisors nor canines are preserved in any of the specimens we
have the opportunity of examining. Two lower-jaw specimens retaining
portions of the incisive, canine, and premolar alveoli, and the true molars,
apparently prove the numl)er of teeth to be as above indicated.

The canine tooth of Hyopsodus is comparatively of small size, though
larger thmi the incisors or the first premolar. It appears to have about the
same size in relation with the other teeth as in Aphelotherium anjd Anoplo-
therium.

The premolars successively increase in size from the first to the fourth.
The first possesses a single fang ; the others two fixngs. The anterior two
premolars are lost from all the specimens under examination.

The inferior true molars (Figs. 1 to 9, Plate VI) of Hyopsodus have
oblong quadrately oval crowns, with the fore and aft diameter exceeding the
transverse, which is about equal to the depth. They are inserted in the
usual manner in pachyderms by a pair of fangs, the posterior of which in
the last tooth is widened backwardly, as is commonly the case in congeneric
animals.

The crowns are composed of four principal lobes, connate at base ; but
the crown of the last tooth has an additional or fifth lobe at its back part as
well developed as some of the lobes in advance. A rudiment of this fifth
lobe is recognized in the other true molars as a small tubercle, occupying a
corresponding position.

The four principal lobes of the crown of the true molars are arranged in
pairs not quite transverse, but slightly oblique, so as to appear somewhat
alternating. The fifth lobe of the last molar is opposite the interval of the
pair of lobes in advance.

Of the four lobes, the outer are demi-conoidal, and the posterior one is
slightly the larger. The inner lobes are simply conical, and the anterior is
the larger. The outer lobes in the unworn condition have acute crescentoid
summits, or form V-like ridges, with the arms declining from the pointed
angle. The inner lobes in the same condition have pointed summits.

The contiguous horns of the crescentoid summits of the outer lobes join
the antero-internal lobe. Tiie anterior horn of the crescentoid summit of the
antero-external lobe curves inwardly to the base of the antero-internal lobe.

Tlic jiosterior lioni of tlic crescentoid summit of tlic postero-extenial lobe
ends in the tubercle at the back of the crown, and in tiie last molar, in the
homologous fifth lobe. The latter is joined by an acute ridge, descending to
the base of the postero-internal lobe.

A thin basal ridge exists at the fore and back parts of the crown of the
first and second molars, and the fore part in the last molar. An element
also exists at the interval, externally, of the outer principal lobes, and in some
specimens is more or less produced around the bottom of the antero-external
lobe.

As the crowns of the true molars are worn away, circular islets of dentine
appear at the summits of the inner lobes, and crescentic islets at the summits
of the outer' lobes. In the progress of attrition the dentinal surfaces expand,
and the horns of the crescentic islets become united with the circular islets.
In an advanced stage of wear the triturating surface of the molars presents two
elliptical surfaces crossing the crown, with a slight obliquity, and united by a
median isthmus, the whole bordered by a band of enamel. Such a condition
is seen in the specimen represented in Figs 1, 2, Plate VI, which is that
upon which the genus was originally proposed. By comparing this with the
others in different stages of wear, represented in Figs. 3 to 9, of the same
plate, its correspondence with these, whicli preserve more characteristic
generic marks, can be readily recognized.

The last lower premolar of Hyopsodus (Figs. 5, 8, Plate VI) is smaller
than the true molars, and like them is inserted by a pair of fangs. Its crown
is proportionately of greater depth than in the true molars, and, as in these, is
widest fore and aft. The outer fore part of the crown is composed of a demi-
conoidal lobe, which is the principal one, and it corresponds with the antero-
external lobe of the true molars. It has the same form as the latter lobe, but is
better developed. The anterior horn of its crescentoid summit forms a curved
ridge, defining the fore part of the triturating surface of the crown. The poste-
rior horn of the crescentoid summit terminates in a small conical lobe occupying
the middle of the crown internally. The back of the crown is tbrmcd By a
broad heel, skirted by a basal ridge externally, and divided by another ridge,
which descends from the summit of the principal lobe of the crown, and bor-
ders the heel posteriorly and internally. A thin basal ridge occupies the fore
part of tlie crown. In the wearing of the crown of the last premolar, the
exposed dentine assumes the Ibrni of the Greek letter t, lying on its right
side.

The penultimate lower premolar (Fig. 8) is a reduced form of the one
behind, with the internal median conical lobe obsolete.

The lower jaw has its two rami co-ossified at the symphysis. It is thick
and rounded at the base, which is convex fore and aft beneath the molar
series. The chin is rounded transversely. The masseteric fossa is well
marked and defined anteriorly by a prominent ridge descending from the
front border of the coronoid process to the lower third of the side of the jaw.

The ramus of the jaw would appear to have increased in depth and
assumed a more robust condition in the advance of age, for in those specimens
in -which the teeth are least abraded, the jaw is shallowest, and in that in which
they are most worn it is deepest. Specimens exhibiting the teeth in an
intermediate state of wear have the jaw of intermediate depth and strengtli
to the others.

All the specimens represented in Figs 1, 3, 4, 6, and 7 I attribute to the
same species, notwithstanding the difference in the proportion of length lo
depth in the different ones.

Two or three mental foramina occupy a slightly variable position beneath
the premolars.

During the summer of 1871, Dr. Carter discovered, at Grizzly Buttes and
Lodge-Pole Trail, several specimens, consisting of fragments of upper jaws
with well-preserved teeth, which are of a size and form that would adapt
them to the lower-jaw specimens of Hyopsodus. 'I'he specimens from
Grizzly Buttes were accompanied by one of the lower-jaw specimens upon
wliich the latter was founded, and this looks sufficiently like several of them
in general appearance to have belonged to the same individual.

One of the specimens represented in Fig. 18, Plate VI, contains a series
of three premolars and the succeeding molars. In advance of the series there
remains a portion of an alveolus which apparently belonged to another pre-
molar. If such is the case, the number of premolars would be the same as_
in the lower jaw of Hyopsodus.

The teeth (Figs. 18 to 22) increase in size from the first to the sixth, the
seventh being again reduced to the size of the fifth The second premolar
is inserted by a pair of fangs of which the posterior is wider than the other.
The succeeding premolars and molars are inserted with three fangs, of which
the inner one of the molars is a connate pair.

Tiie crowns of the molars (Figs. I'J to 21) are quadrate, wider transversely,

and abt)iif halt (he depth ot" the breadth. They arc composed each of six
lolies expanding and continuous at base. The outer and inner pair of lobes
are nearly equal ; the intermediate pair is smaller.

The outer lobes of the molars are conical, and united where contiguous,
but they do not form an external buttress by their union, the intei'vening
surface externally being concave. In the last molar the posterior of the outer
lobes is proportionately less well developed than in the others.

The inner lobes of the crown are likewise conical, and united where con-
tiguous. The posterior of tiiese lobes is the smaller, and in the last molar is
entirely suppressed, or appears only as a slight elevation of the basal ridge
occupying the back of the crown. The summit of the antero-internal lobe
is prolonged obliquely to join the antero-median lobe. The summit of the
postero-internal lobe is prolonged outwardly back of the postero-external
lobe, so as to appear as a basal ridge to this part of the crown.

The median lobes hold a slightly more advanced position than the includ-
ing lobes. The back one is isolated or free to its base ; the front one, by
prolongation, is associated with the antero-internal lobe and the fore part of
the base of the antero-external lobe.

A strong basal ridge occupies the fore part of the crown, and also, less well
developed, festoons the outer part.

In the wearing of the upper molars (Figs. 19 to 21) islets of dentine first
appeared at the summits of the six lobes of the crown. Those of the two
outer lobes soon became continuous ; followed by those of the antero-median
and anteror internal lobes With the widening of these two tracts, the islet
of the postero-internal lobe next became continuous with that in advance.
At this stage there would appear three dentinal tracts: one lor the outer pair
of lobes, a second for the internal and antero-median lobes, and a third as a
circular islet on the postero-median lobe.

The posterior two premolars (Figs. 19, 21) have bilobed crowns, remind-
ing one of the premolars of ruminants. The sudden reduction from the six
lobes of the crown of the molars to the single pair of the crown of the pre-
molars is a remarkable anatomical character. The lobes are pyramidal, and
so far spread apart as to give the crown a greater width transversely. The
summit of the inner lobe forms a crescentoid ridge, embracing the bottom of
the outer lobe. A strong basal ridge bounds the fore and back part of the
crown, and festoons it externally.

In the Uiird premular the inner lobe is less well developed at its fore part
than in the fotirth.

The crown of the second premolar (Figs. 19, 22) is formed of a single
conical lobe, corresponding with the external lobe of the succeeding tooth.
Postero-internally, it presents a feeble rudiment of an inner lobe. The
crowns of the premolars were worn away mostly in a slanting manner poste-
riorly. The exposed dentine in the two lobed crowns became continuous at
». the back of the crown.

The molars above described resemble, in construction and in the relative
position of the six lobes of the crown, those of Hyracotherium and Pliolophus,
two extinct genera of pachyderms, described by Professor Owen from remains
found in the London clay, an Eocene formation of the estuary of the Thames.
In both the genera named the last molar is ])roportionately better developed ;
and in all the molars the postero-internal lobe and the basal ridge are likewise
proportionately better developed. The upper pi-emolars are quite different..
In Hyracotherium the back t\yo premolars have five lobed crowns, and in
Pliolophus the last premolar has a similar constitution.

Too small a portion of the jaw (Fig. 18) containing the teeth above
described has been preserved to ascertain anything of importance as to the
shape of the face. The infra-orbital foramen is situated immediately above
the interval of the back two premolars.

Measurements from some of the upper-jaw specimens and teeth above
described are as follows :

Specimens in Plato VI.

Figs. 18,19.

i Lines.

Si)ace occupied by series of six molar teetb 9

Space occupied liy true molars 5 J

Space occupied by tbree premolars 3^

Breadtb of .second premolar 1

Widtb of second premolar 1

lireadtli of tbird premolar ' IJ

Width of tbird premolar li

Breadtb of fourth premolar i 1^

Width of fourth premolar 2

Breadth of first molar '' 1^

Width of first molar ' 2^

Breadtb of second molar i 2

Widtb of secoud molar 2J

Breadth of last molar 1^

Width of last molar 2

Fig. 20.

U
2i

Lows.

incs.

•

HyOPSODUS MINU6CULU.S.

A smaller species of Hyopsodus than the one described in tlic jireceding
pages appears to be indicated by a specimen discovered by Dr. Carter in the
buttes of Dry Creek. The specimen consists of an upper-jaw fragment con-
taining the true molars and part of the last premolar, which are represented
in Fig. 5, Plate XXVII. The teeth differ in no essential character and only
in size. Their com partitive measurement with those of H. paulus are as
follows :

Hyopsodus
mimisculiis.

Hyopsodus
paulus.

Leugtli of space occupied by the last premolar ami molars. .

Length of space occupied by the molars

Breadth of last premolar

Width of last preaiolar

Breadth of tirst molar ,

Width of first molar

Breadth of secoud molar ,

Width of second molar

Breadth of third molar -

Width of third molar

Lines.
5,4
4.4
1.05

Lines.

6.45

5.2

1.4

2 2

1.8

2.4

2.0

2.8

1.6

2.35

MICROSUS.

MiCROSUS CUSPIDATUS.

The genus Microsus is obscurely determined and is uncertain in its distinc-
tion from the previous genus. It was originally inferred from the lower-jaw
fragment with the back two molars, represented in Fig. 10, Plate VI, at the
same time that Hyopsodus paulus was characterized from the only specimen
then in our possession, represented in Fig. 1 of the same plate. The well-
marked difference in the form and proportion of the corresponding portion of
the jaw led me to view it as pertaining to a diffei'ent genus fi'ora Hyopsodus.
Subsequently I have had the opportunity of examining many and more char-
acteristic specimens referable to the latter, but none which with any certainty
could be ascribed to Microsus.

The jaw-specimen referred to the latter was obtained by Professor Hay-
den on Black's Fork of Green River. The jaw would appear to be narrower
and weaker than hi Hyopsodus. The fragment as seen in Fig. 10, in com-

11 G

parisoii with corresponding portions ofllic latter, as seen in Figs. 1,3,4, 7, is
proportionately of less depth, and at the base beneath the molars curves
much more upwardly in a back-ward direction.

The teeth, represented in Figs. 10 and 11, are unworn, and they liave the
same size and constitution as those of Hyopsodus. In the specimen the con-
stituent lobes of the crown appear more prominent and their intervals more
deeply angular than in those of Hyopsodus, but this difference is probably
due to difference in age. In all the specimens ascribed to Hyopsodus the
teeth are more or less worn, and only in that attributed to Microsus are they
unworn. Observing, also, that the proportionate depth of the lower jaw in
the different specimens of Hyopsodus holds some relationship with the age
of the animal, as indicated by the extent of wearing of the teeth, I have sup-
posed that the variations observed in the jaw-fragment of Microsus might be
due to the same cause, and that it therefore really pertains to Hyopsodm jjau-
lus. Thus by comparison of Fig. 10, representing Microsus, with that of
Fig. 6, representing a specimen of Hyopsodus, in which the teeth are least
worn, the resemblance is observed to be greater than with the other and
older specimens of Hyopsodus.

Comparative measurements of the specimen referred to Microsus with
specimens of Hyopsodus represented in Figs. 1, 3, and 6 are as follows:

Depth of lower jatv at fore part of last molar

Space occupied by last two molars

Auteroi)osterior diameter of last molar

Antei'o-posterior diameter of second molar. .

Microsus.

Lines.

"5"

Hyopsodus.

Via. 10. Fig.- 1

Lines.

Fig. 3. Fig. 6.

Lines.

MICROSYOPS.

An extinct genus of small mammals, to which the above name was given,
was originally founded, on several lower-jaw fragments containing molar teeth.
Though classed among the pachyderms, it is not positive that such is the true
position of the genus. The more complete of the specimens upon which it
was characterized indicates a series of six molar teeth following closely after
a well-developed canine. The number of incisors is unknown.

In the genus Limnothoriuni, as established by Professor Marsh, from the
typical species Z. ti/nmnus, the dental formula consists of two incisors, a
canine and seven molars.

Mycrosyops gracilis.

The more characteristic specimen upon which this species was named con-
sists of a portion of the left ramus of the lower jaw, represented in Fig. 14,
Plate VI, of the natural size. The specimen was discovered by Dr. Carter
on Grizzly Butte. Besides the fang of the canine and those of the premolars,
it contains the true molars entire. These are moderately worn at the sum-
mits of the constituent lobes of their crowns, and their triturating surfaces
are represented in Fig, 15 of the same plate, magnified four diameters. The
jaw-fragraent retains part of the rough sutural surface of the symphysis, show-
ing that its union was ligamentous with the other ramus. The basal portion
beneath the molars is broken away. Below the premolars it is of moderate
depth and thickness, and soon curves upward with the fang of the canine. The
mental foramen is situated below the second premolar. The fang of the
canine indicates a proportionately larger tooth than in Hyopsodus. It is lat-
erally compressed and curves ujjward, forward, and t)utward. The transverse
section is oval with the long diameter directed obliquely forward and out-
ward, and measuring 1.8 line, while the short diameter is 1 line.

The premolars successively increase in size. The first is separated by a
slight hiatus from the canine, and was inserted by a single fang. The others
have two fangs.

The molars have oblong quadrately-oval crowns of nearly uniform size.
They are inserted with two fangs, with the back one of the last molar widened,
as usual in most ungulates.

The crown of the molars is composed of two divisions, in addition to
which the last one has a large posterior tubercle. The anterior division of the
crown is smaller than the posterior, and appears of the same form in a more
contracted condition. Each division consists of an external crescentoid coni-
cal lobe and an internal rudimental conical lobe or tubercle, whicli is placed
opposite the back part of the former lobe.

The front arm of the anterior crescentoid. lobe ends in a thickening in ad-
vance of the antero-internal lobe. Tlie corresponding arm of the better de-
veloped posterior crescentoid lobe terminates at the base of the lobe in front
of it. The back arm of the same lobe forms a slight thickening contiguous

to thr. postero-intenjal lobe. In the last molar this thickening appears to be
developed into the large tubercle back of the second division of the crown.
Feeble traces of a basal ridge occupy (he interval of the outer lobes and the
• back of the crown.

Measurements of the lower-jaw specimen oi Microsyojjs gracilis. are as fol-
lows :

Lines.

Depth of lon-er jaw below last molar 4

Thickuess of lower jaw below last premolar 2J

Distance from canine alveolus to back of last molar 10

Space occupied by the entire molar series , 9|

Space occupied by tbe premolars 4

Space occupied by the molars » 5|

Breadth of first molar 1^

Breadth of second molar ., 2

Breadth of third molar 2

The specific name of 31. gracilis was originally given under the impression
that the remains referred by Professor Marsh to Hyopsodus gracilis pertained
to the same animal. A specimen exhibited to the writer by Professor Marsh
would indicate that M. gracilis is the same as the animal named by him
Limnothcrium elegans. As Microsyops is generically distinct from Limno-
therium, as characterized from the typical species L. tyrannus^ the specific
name of the former would be Microsyops elegans.

Another specimen, originally referred to Microsyops gracilis, is represented
in Fig. 16, Plate VI, and was found by Dr. Carter near Lodge-Pole Trail,
about tea miles from Fort Bridger. It consists of a portion of the left ramus
of the lower jaw, containing the j^enultimate molar and part of the last one.

The only remaining entire molar, a view of the triturating surface of
which is given in Fig. 17, closely resembles the corresponding tooth in the
specimen first described, except that it is a little larger. (The artist has
made it appear different by exaggerating the proportions of the tubercle be-
tween the posterior lobes, and leaving it out altogether in the corresponding
view of Fig. 15.) The remaining portion of the last molar also agrees with
the corresponding portion in the first-described specimen. The lower jaw is
comparatively deep, and is nearly straight along the base. The fore part
with the symphysis is lost, but it would appear not to have been so shallow
and thick as in the former specimen, which leads me to suspect that it
perhaps belongs to a different animal. The mental ibramen holds the same
relative position as in the other specimen. The ridge bordering the lore

jiaii (){' (lie coroiioid process terminates in a tul)ercle at the fore part ol Ihe
moderately deep masseteric fossa.

Another foramen, perhaps not constant to the species, is situated below
tlie position of the fore part of the first molar.

The measurements of the specimen are as follows:

Lines.

Depth of jaw below last molar -if

Depth of jaw below last premolar 4^^

Space occupied bj' last i)remohir and molars 7^

Space occupied by the molars 0

Breadth of penultimate molar 2J

Breadth of last molar 2^

The only specimen of an upper tooth which may, with any probability, be
supposed to belong to Microsyops, is contained in a small fragment of the
jaw, found by Dr. Carter on Dry Creek. The tooth, apparently a first or
second molar, is represented in Figs. 19, 20, Plate XXVII. The crown is
not so square and is proportionately of less breadth fore and aft than in the
corresponding tooth of Hyopsodus. It narrows inwardly more than in the
latter, the reduction taking place posteriorly, where the crown is concave.
The constitution of the tooth is nearly as in Hyopsodus, and the principal
difference is found in the condition of the postero-internal lobe. In Hyopso-
dus, this is a reduced form of the lobe in advance, being crescentoid. In the
supposed tooth of Microsyops, the postero-internal lobe appears as a conical
tubercle springing from the base postero-internally of the larger crescentoid
lobe in front. In Hyopsodus, the postero-median lolje is a simple cone, but
in the tooth in question it is pyramidal.

The antero-posterior diameter of the crown external!}' is 1.6 lines ; inter-
nally, 1.2 lines; the transverse diameter anteriorly is 2.2 lines.

Undetermined.

Fig. 12, Plate VI, represents a specimen found by Dr. Carter on Henry's
Fork of Green River. It consists of a lower-jaw fragment with the last pre-
molar and the fangs of the molars of a mature animal of undetermined
character, but, from the form of the remaining tooth, evidently allied with
Hyopsodus. The premolar. Fig. 13, is unlike the corresponding one of the
latter genus, as seen by comparing it with Figs. 5 and 8, but resembles tlie
true molars. Suspecting that it might be a last temporary molar, notwith-
standing its slightly worn condition and its association with the full series of

molars in functional ])ositiou behind, 1 examined the jaw beneath, Init fouiKl '
110 trace of a successor.

The portion of jaw is of more uniform depth, and the base less convex
than in Hyopsodus. It is also more impressed and concave below the position
of the back molars. The space occupied l\y the molars is about equal to
that in the smaller specimens of Hyopsodus.

Perhaps the sjiecimen may pertain to Microsus, or prol^ably may l)elong to
a genus difTerent from either of those just named. Its measurements are as
follows :

Lines.

Space occupied by tlie last premolar aud molars 7f

Space occupied by tbe molars ■ . . 5|

Depth of jaw at fore part of last molar '3^

Depth of jaw at last premolar Sf

Anteroposterior diameter of last molar 2i

Anteroposterior diameter of last i^remolar If

NOTHARCTUS.

NOTHAKCTUS TENEBROSUS.

A small extinct pachyderm, referred to a genus with the above name, judg-
ing from the anatomical characters of the specimen upon which it was founded,
was probably as carnivorous in habit as the raccoon and bear. The specimen
to which I allude, represented in Fig. 36, Plate VI, consists of tbe right
ramus of a lower jaw with most of tbe teeth. It was discovered during Pro-
fessor Hayden's exploration of 1870, on Black's Fork of Green River. I at
first viewed it as pertaining to a carnivorous animal, and thus referred it ; but
tbe anatomical relations of the specimen with those of remains of other ani-
mals which have been found in association with it have led me to view the
jaw as having belonged to a pachyderm. The ramus of the ja^v contained a
series of seven molar teeth, all of which are preserved except the first pre-
molar'. A well-developed canine occupies a position immediately in advance
of the molar series, and the incisors filled the interval between the canines of
the two sides. Thus the teeth of the lower" jaw of Notliarctus form an un-
broken arch. The incisors are lost from the specimen, and the condition of
the alveoli is such that the number of them cannot be ascertained.

The canine tooth of Notharctus in its relative position, form, and propor-
tions resembles that of ordinary carnivores. It curves from the opening of
the alveolus slightly backward witli an inclination outward. The crown is

considerably elevated from an increased jirolrusion (if the fang, sucli as is
observable in carnivorons animals past maturity. Tlie fang is gibbous and
feebly curved.

The molar teeth, represented in Fig. 37, magnified two diameters, are con-
siderably worn in the specimen, all of therrt exhil)iting exposed tracts of den-
tine, due to the wear of mastication.

The four premolars successively increase in size, and are inserted by a pair
of fangs, except the first, in which they appear to have been connate. The
crowns of the premolars from behind forward exhil)it a successive reduction
to a simpler form from that of the molars.

The crowns of the second and tliird premolars, and no doubt also that of
the first one, which is lost from the specimen, have the conical form of the
corresponding teeth in carnivores, though they appear less prominent, due to
their worn condition. They are slightly thickei" behind than in front, and a
basal ridge internally forms a slight offset or heel posteriorly, and a still feebler
one in the third premolar anteriorly.

The crown of the fourth premolar is intermediate in character with tliose
in advance and those of the molars behind. Its fore part consists of a conical
lol)e like the crown of tlie anterior premolars ; its back part is a broad heel
corresponding with the back lobe of the molars. The summit of the princi-
pal lobe is extended obliquely inward and backward and is continuous with
the inner basal ridge of the crown. Externally, the latter is embraced by a
basal ridge.

The crown of the second premolar is worn away along its posterior slope ;
tlie crown of the third to a greater degree in a corresponding position, and
also to a less degree along its anterior slope.

. The molars are nearly alike in form and constitution, and are inserted with
two fangs. The crown of the molars bears a certain degree of resemblance
in construction to those of the raccoon, and in a less degree to those of the
opossum, but certainly enough resemblance to both to indicate a relation
which is not merely accidental.

In the unworn condition of the lower molars of Notharctus, the crown
would appear to be composed of two divisions. The anterior division pre-
sents three prominent points continuous in an acute crescentoid ridge. The
principal point is central and external, the second is nearly as well developed
and internal, and the third point, feebly developed, occupies the fore part of

the crown The posterior division presents two elevated points, conjoined in
a crescentoid ridge. The anterior extremity of this ridge joins the front
division of the crown. Its more elevated point is extemal and posterior, and
its less developed one occupies the postcro-internal corner of the crown. A
l)asal ridge incloses the crown, except internally.

Each division of the crown of the molars incloses in the arms of its cres-
centoid ridge a depression, which is largest in the posterior division. The
crown of the last molar is more prolonged backward than the others, arising
from the greater degree of development in this direction of its posterior
division.

In the worn condition of tlie molars, as seen in Fig. 37, the crescentoid
ridges of the divisions of the crown have been so much abraded as to expose
broad crescentoid tracts of dentine continuous on the two divisions of the
crown.

The rami of the lower jaw of Northarctus appear to be co-ossified at the
symphysis, and the specimen under consideration was broken off just to the
left of the latter. The chin is narrow and convex transversely, and it forms
a nearly straight or slightly convex slope of about 45°. The body of the
bone is nearly of uniform depth; the relation of depth to length being much
greater than in the raccoon and more in proportion witli the measurements
in the hog and peccary. The outer flice of the body is nearly vertical. I'he
base is thick and slightly convex fore and aft. Near the middle, directed in-
wardly, it exhibits a'strong impression tor muscular attachment.

The angle of the jaw, the back border of the bone, and the coronoid pro-
cess ai'e lost. The outer face of the ascending portion of the ramus is
depressed into a masseteric fossa extending nearly or quite to the base, but
shallow compared with that of ordinary carnivores. The. condyle is remark-
ably slioi't, and resembles that of some of the monkeys more than that of ordinary
pachyderms. It is transversely oval, with the l^readth less than twice the
fore and aft diameter, which is directed obliquely from without inward and
backward. The articular surface is transversely convex and inclines more
outwardly than inward.

The form of the condyle clearly indicates more varied movements in the
jaw than exists in the carnivora, and would rather be favorable to the proper
reduction of the food of an omnivorous animal.

A mental foramen occupies a position about mi<lway between the third

premolar ami lliu base ol the jaw. Twu small loramiiia arc situak'd IjcIow
the position of the first premolar.

Ill the American Journal of Science for 1871, Professor Marsh has
described the lower jaw, with teeth, of a small pachyderm, under the name of
Limnotherium tyrannus, which would appear at least to belong to the same
genus as the former. The specimen was found near Dry Creek, Wyoming.
According to the description and measurements, the jaw nearly accords with
that of Notharctus tenebrosus. The teeth in an interrupted series consist of
two incisors, a canine, four premolars, and three molars. If we suppose
Notharctus to have two incisors, the numljer, character, and relative position
of the teeth agree in both. In Limnotherium the first and second premolars
are observed to have a single fang. This character alone would be insufficient
to distinguish a genus, and, perhaps, would hardly be regarded as a specific
character. The description of the molars of Limnotherium would apply to
those of Notharctus.

The measurements of the lower-jaw specimen o? Notharctus tenebrosus are
as follows :

Liucs.

Leugtli of jaw from condyle to incisive alveoli 30

Depth of jaw below last molar 5^

Depth of jaw below last premolar C

Length of symphysis '^

Breadth of condyle j

Anteroposterior diameter of condyle 2

Length of dental series - 19^

Length of space occupied by the molar series Iti

Length of space occupied by the true molars S^

Diameter of canine at base of crown 1|

Fore and aft diameter of second premolar li

Transverse diameter of second premolar f

Fore and aft diameter of third premolar If

Transverse diameter of third premolar li

Fore and aft diameter of fourth premolar 2

Transverse diameter of fourth i)remolar l-J

Fore and aft diameter of first molar 2f

Transverse diameter of first molar , 2

Fore and aft diameter of second molar ^ ~'i

Transverse diameter of second molar 2

Fore and aft diameter of third molar 3^

Transverse diameter of third molar 2

In numy respects the lower jaw of Notharctus resembles that of some of
the existing American monkeys quite as much as it docs that of any oi the
living pachyderms. Notharctus agrees witli most of tiie American monkeys
12g

ill tlie union of llie rami of tlie jaw at the sj'inpliysis, in the small size of the
condyle, in the crowded condition of the teeth, and iu the number of incisors,
canines, and true molars, wliich are also nearly alike in constitution. Notharc-
tus possesses one more premolar and the othei's have a pair of fangs. The
resemblance is so close that but little change would be necessary to evolve
from the jaw and teeth of Notharctus that of a modern monkey. The same
condition which would lead to the suppression of a first premolar, in continu-
ance would reduce the fangs of the other premolars to a single one. This
change, with a concomitant shortening and increase of depth of the jaw, would
give the characters of a living Cebus. A further reduction of a single premo-
lar would give rise to the condition of the jaw in the Old World apes and man.

IIIPPOSYUS.

HlPPOSYUS FOEMOSUS.

Several small fragments of jaws with teeth, discovered by Dr. Carter in
the vicinity of Fort Bridger, are suspected to belong to a different genus of
pachyderms from any of those indicated in the jjreceding pages. One of the
specimens consists of an upper-jaw fragment with the molars in a mutilated
condition. The first and second molars are the l)est preserved, and are rep-
resented in Fig. 41, Plate VI, magnified three diameters. The first one is
nearly entire, but in the figure is represented in a restored condition by the
addition of the antero-external angle marked l:)y the zigzag black line.

The upper molars bear a general resemblance in the construjction of their
crowns to those of Anchitherium. The outer lobes are like those in the lat-
ter, but have their outer buttress-like ridges proportionately thicker. The
antero-intei-nal lobe is larger than that behind and conjoins it. In Anchitherium
the inner lobes are nearly equal and isolated from each other. The antero-
median lobe, as existing in Anchitherium, in the present fossil is completely
connate as part of the antero-internal lobe, and the postero-median lobe of
the former is nearly obsolete, or appears as a mere rudiment in Hipposyus.
A strong basal ridge incloses the crown in front, behind, and internally, but
is absent in Anchitherium in the latter position.

The measurements of the specimen are as follows:

Lines.

Space occupied by the three molars T^i

Breadth of first molar ^i

Breadth of second molar ' oa

■"4-

Breadth of third molar , 2i

Width of first molar transversely 3i

The other specimens aeeompanyiiig the tbnner, and siisixTled lo Ixdoiig to
the same species, consist of fragments of three lower jaws, containing each
one or two molar teeth. One of the specimens contains the first and second
molars and the remains of the last one. The portion of jaw is like the corre-.
sponding portion in Notharctus, but is thicker and the teeth are stouter. The
teeth are considerably worn, as represented in the view of the triturating sur-
face of the second molai- in Fig. 38, Plate VI, magnified two diameters. The
crown is ol)long square, and consists of two divisions, each of which, in tlie
unworn condition, presented au acute crescentoid summit In the abraded
condition the divisions present two broad, semi-lunar tracts of dentine con-
tinuous with each other. The tracts embrace, internally, shallow enameled
recesses, of which the posterior is much the larger. The contiguous horns
of the tracts are continuous upon a tubercle at the inner part of .the crown
just in advance of the middle. The posterior horn of the posterior crescent
is likewise continuous, with a tubercle at the postero-internal angle of tlie
crown. Externally the latter is bounded by a basal ridge, and an element of
the same occupies the postero-internal angle of the crown.

Measurements of the specimen are as follows :

Liues.

Depth of jaw below the middle molar i'>^

Space occupied by the three molars ••

Breadth of crowu of first molar 2 J

Width of crown of first molar 2

Breadth of crown of second molar ....'. ^ 3

Width of crowu of secoud molar 2^

A second specimen consists of a nearly corresponding portion of another
jaw containing the first and second molars. The jaw-fragment is of greater
depth than in the former, but otherwise is about as robust, and the teeth are
nearly of the same size. The measurements are as follows:

Liues.

Depth of jaw below middle molar Sf

Breadth of crown of first molar 23-

Width of crown of first molar " 2^

Breadth of crown of second molar 2^

Width of crowu of second molar 2J

Two additional specimens consist of portions of both rami of the lower jaw
of a younger animal than the preceding, but only one contains a single tooth,
the first molar, which is represented in Fig. 39, Plate VI, magnified two
diameters. The rami of the jaw are of more slender proportions than indicated

hy the fragments above descril)ed, but are nearly as thick ; and the retained
tooth is of the same size and form as its fellow in the fragments of older jaws.

One of the rami contains the fangs of the complete molar series, together
with part of the canine alveolus, which is close to the former. The number
of premolars I cannot determine with certaintJ^ If tliree, the first of the
series is larger than the second, and has its fangs more widely separated. If
the number is four, the anterior two have each a single fang.

Perhaps the latter is the true condition, which accords with that attributed
to Limnotherium by Professor Marsh.

Three vasculo-neural foramina are situated at the outer part of the ramus:
one just back of the position of the canine alveolus ; a second below the
interval of the back two premolars, and the third beneath the first molar. In
the opposite ramus the latter is below the last premolar, and it occupies the
same i)osition in the former two specimens.

The first molar tooth retained in one of the rami agrees with the descrip-
lion of those in the older jaw-fragments. Fig. 38, Plate VI, represents the
right second molar much worn ; and Fig. 39 represents the first left molar
in a much less abraded condition.

Measurements from the two rami of the lower jaw just described are as
follows :

Lilies.

Space occupied by the premolar aud molar series IGJ

Space occupied by tbe molar series 9

Depth of jaw below the premolars 5

Depth of jaw below the middle molar 4|

Breadth of the first molar 3

Width of the first molar 2^

Figs. 1, 2, Plate XXVII, represent a specimen of a tooth recently discov-
ered by Dr. Carter on Grizzly Buttes. It appears to be a first upper true
molar of Hippcmjus formosus, and is scarcely worn. It was found isolated
and unaccompanied by any other pieces which could be reasonably atti-ibuted
to the same animal. From the comparative perfection of its crown, its con-
stitution is more evident. It resembles in miniature the corresponding teeth
of Anchitherium, and ditfers especially in the less proportionate development
of the median lobes of the crown, in the greater degree of production of the
basal ridge, in the more intimate union of the inner lobes and their more
sloping character externally, in the more isolated condition of the postero-
median lobe from the contiguous inner one, and in the more wrinkled condi-

tion of all the lobes approaching the base of the crown. The transverse
diameter of the latter is J of an inch; its fore and aft diameter externally ^
of an inch.

HiPPOSYUS ROBUSTIOR.

A lower-jaw fragment containing a single tooth, obtained by Professor
Hayden on Henry's Fork of Green River, apparently indicates a more robust
■species of the same genus as the former. I at first attributed the specimen
to a species of Notharctus, with the name of JV. rohustior, but a comparison
of the tooth, represented in Fig. 40, Plate VI, with those o'i Hipposyus fonno-
sus, Figs. 38, 39, will at once suggest the probability of its pertaining to a
larger species of the latter genus. Perhaps' the specimen may belong to a
more robust individual of the same species.

The jaw-fragment is too imperfect to ascertain anything in regard to its
anatomical characters other than its thickness. Below the second molar it is
J of an inch thick; in the specimens attributed to H. formosus it ranges in the
same position from 34^ to 3J lines in thickness. The second molar tooth is
3i lines broad and 2^ lines wide.

Order Prohoscidea ?

Large quadrupeds with fivettoes to the feet ; molar teeth with transverse
ridges; femur without a third trochanter; nose prolonged into a cylindrical
trunk or proboscis.

UINTATHERIUM.

While encamped in Dry Creek Cafion, forty miles to the east of Fort
Bridger, Drs. Carter and Corson spent a day in traversing a most desolate
region to some buttes about ten miles farther to the east. They returned to
camp after sundown laden with fossils, among which were the remains of the
largest animal which had yet been brought to our notice from the Bridger
Tertiary beds. '^J^hese remains consist of the cranial portion of a skull with
fragments of both jaws attached to the same matrix, a nearly complete arm-
bone, and fragments of other limb-bones. A notice of these remains, attrib-
uted to a pachyderm with the name of Uintathcrium rohustum, was com-
municated in a letter to the Academy of Natural Sciences of Philadelphia,
and was published August 1, 1872.

On the jJrevious day to the discovery of the remains of Uintatherium,
while engaged in the search for fossils along the buttes, al)ou( a mile to the

east of our camp, Dr. Corson called my attention to a large tusk which he had
found mingled with some drift-pebbles that had tldlen from the top of the
butte. In the tusk I thought I recognized the canine of a large carnivore
related to the extinct saber-toothed tiger of Brazil. On further search, we
iound a j)ortion of the opposite tusk, an isolated molar supposed to belong to
Uintatherium, another of Palseosyops, and the scale of a ganoid fish.

In tlie same letter above mentioned, the large tusks were described and
attributed to a carnivore with tiie name of Uintamastix atrox.

On our return to Fort Bridger, while examining and discussing the fossils
collected in our expedition, the question arose whether the large tusks did not
pertain to the same animal I have named Uintatherium. Our specimen of
the skull of the latter did not assist the determination of the question, as the
facial portion was wanting, excepting small fragments of the back of the jaws
containing the last molar teeth. While admitting the probability of the tusks
pertaining to Uintatherium, from their being so unlike those of any known
pachyderm, and from their near resemblance, both in form and size, to ihose
of the great extinct Machairodus of Brazil, I thought the weight of evidence
was in favor of their reference to a carnivore. The finding of a molar tooth
of Uintatherium in association with the tusks appeared to me not to outweigh
this evidence any more than the association with them of a molar of Palgeo-
syops.

Professor Marsh has published several notices in the American Journal of
Science of the remains of large mammals from the Bridger Tertiary forma-
tion, which appear to be related with Uintatherium.

In June, 1S71, he reported the discovery of bones of a large animal which
he referred with doubt to Titanotherium, with the name of T. anceps. From
some additional remains, in a foot-note of July 22, 1872, he refers them to a
proboscidean under the name of Mastodon anceps. This is corrected in an
erratum of August 19, referring the animal to a new genus with the name
of Tinoceras anceps. September 21, he j^ublishcd a notice of a new species
with the name of Tinoceras grandis, founded on portions of a skull and teeth,
&c. Of this he observes, " The skull is proportionately very small, and indi-
cates one of the most remarkable animals yet discovered. It sujiports a pair
of short horns, and has also two powerful tnsks, which, in size, shape, and
direction, resemble the canines of the walrus."

More recently, September 27, Professor ]\Iarsh has published a "notice of
son>e remarkable fossil mammals," which are referred to two species of a new

genus with the names of D'mocerus vurahiLh and I), lacusttis. OC tin; skull
ot this genus, he observes that it presents a most remarkable combination of
cliaracters. "It is wedge-shaped, elongated, and <|uite narrow, especially in
front, aiul was armed with horns and huge decurved canine tnsks. The tt)p
of the skull, moreover, is deeply concave, and has around its lateral and pos-
terior margins an enormous crest. On the frontal bones, above the orbits,
and in advance of the lateral crest, there is a pair of very large horn-cones,
just behind and above the canines. These are directed upward and outward,
and their summits are obtuse and nearly round. They are solid, except at
the base, wdiich is perforated by the upper extremity of the canine. Near
the anterior margin of the nasals there is still another pair of horn-cones,
which are near together, and have obliquely compressed summits. The nasal
opening is small. The premaxillaries are slender and without teeth. The
upper canines are greatly elongated, slightly curved, and compressed longi-
tudinally. The lower portion is thin and trenchant. Behind the canine is a
long diastema, t-bllowed by a series of six small teeth. The molars have their
crowns composed of two transverse ridges, separated externally, and meeting
at the inner extremities. The skull measures about 28i inches long and 8^
inches in width over the orbits. The canine is 9:^ inches in length below
the jaw, G4 millimeters in longitudinal diameter at base, and 25 millimeters
in transverse diameter. The last upper molar has an antero-posterior diameter
of 36 millimeters."

It appears to me that the brief description of the skull and molar teeth of
Dinoceras applies so closely to the corresponding parts of Uintatherium as
to render it probable they are of the same genus. The description of the
tusks of the former also equally well apply to those of Uintamastix, so as to
lead me to suspect that this may likewise be the same as Uintatherium. It
is probable, too, that should the latter not be the same as Dinoceras it may
prove to be the same as Tinoceras, or perhaps the Eobasileus s. Loxolophodon
of Professor Co]^)e.

The characters of Uintatherium, as expressed in the material at our com-
mand, are so peculiar and unlike those of any other known animal as to ren-
der its ordinal affinities obscure. From the form and constitution of the
molar teeth alone, I should have viewed the genus as pertaining to the odd-
toed pachyderms. If the remains noticed by Professor Marsh under the
name of Dinoceras belong to the same animal, the presence of horns in pairs
to the head would render such a reference improbable. Professor Marsh

observes of Diiioceras and the related Tinoccras, that they have the vertebral
and limb bones very similar to those of recent proboscideans, but refers them
to a new order vvitli the name of Dinocerea.

The form of tlie thigh-bone and the short tarsal bones of Uintatherinm
\\ould appear to indicate limbs and feet most nearly constructed like those of
the elephant. I have provisionally placed the animal in the order of Probos-
cidea, leaving to Professor Marsh the determination of its true position from
the more abundant materials at his command.

UlNTATHERIUM KOBUSTTIM.

The remains which are specially to be regarded as characteristic of the
animal above named, and from which it was originally indicated, consist of a
mutilated cranium, to the matrix of which there adhere'd portions of both
jaws, containing all the last molars and an isolated molar. A nearly com-
plete humerus, together with some less well preserved specimens found in
association with the former, are supposed to have pertained to the same
individual.

A small fragment of the upper jaw, containing the last molar tooth, is rep-
resented in Fig. 8, Plate XXV. The tooth, also represented in Figs. 6, 7,
of the same plate, and Fig. 30, Plate XXVII, has the crown composed
of a pair of wide pyramidal lobes projecting from a broad expanded base.
The lobes extend across the crown, conjoining internally and diverging ex-
ternally in a V-like manner. They project at their outer extremities in promi-
nent points, and also form together a prominent point at their conjunction
internally. The outer extremity of the anterior lobe is the most prominent
of the three points of the crown. The outer extremity of the posterior
Iol)e is the least prominent of the three points, while that at the conjunc-
tion of the lobes is scarcely more so. The acute summits of the lobes
between the points arc transversely concave, and are worn off on their anterior
slope so as to present narrow tracts of exposed dentine. The posterior slope
of the lobes is slightly concave ; and the valley between them is triangular,
and opens outwardly.

From the posterior slope of the inner part of the back lobe of the crown
there projects a rounded tubercle about half-way between the basal ridge and
the pointed conjunction of the lobes. A second rounded tubercle occupies
the entrance of the triangular valley between the lobes.

A stout basal ridge embraces the crown in front and behind, and in a

reduced condition continues interruptedly on the inner and outer parts. In
"outline the base of the crown is ovoidal, with the narrower extremity corre-
sponding with the outer part of the anterior lobe. The tooth is inserted by
a pair of fangs widely compressed, conical, and convergent internally. The
transverse diameter of the crown of the last upper molar is 20 lines ; its fore
and aft diameter is nearly 18 lines. Tlie description of the upper molars of
Dinoccras mirabilis, and the size of the last one, as given by Professor Marsh,
so well apply to the tooth above described as to lead me to suspect that the
animal so named is the same as Uintatherium rohustum.

The fragments of both sides of the lower jaw of the latter, represented in
Fig. 11, Plate XXV, and Figs. 32, 33, Plate XXVII, contain the last molar tooth,
also represented in Figs. 9, 10, of the former plate, and Fig. 31 of the latter.
The tooth has an oblong square crown, rounded at the corners and moderately
constricted at the middle laterally. It is inserted in the jaw by a pair of
wide, compressed conical fangs.

The crown is composed of three lobes, with oblique intervening valleys,
which receive the pair of lobes of the corresponding upper tooth when closed
upon the lower one.

The anterior lobe forms nearly half the crown, and rises internally in a
point, which is the most prominent part of the tooth. The front and back
surfaces are sloping, and the former is transversely concave, and bounded by
a short, oblique basal ridge. The inner and outer surfaces of the extremities
are convex, and extend to the bottom of the crown. The acute summit
curves downward and outwai'd from the inner point. It is worn off on the
posterior slope with a more forward direction externally, and exhibits a nar-
row tract of exposed dentine. The prominent point of the inner extremity
is notched just below the summit postero-internally.

The posterior and middle lobes of the crown are nearly of the same size
and prominence. The posterior lobe is separated from the anterior lobe
internally by a deep, angular notch, and diverges from it externally. It
forms the posterior convex surface of the crown, and has an anterior sloping
surface defined from it by a ridge curving from the inner side backward and
outward, and then becoming continuous, with a basal ridge sweeping down-
ward to the bottom of the middle lobe of the crown externally. The middle
lobe appears like an ovoidal wedge introduced from the outer side, and sepa-
rating the anterior and posterior lobes. Its summit is worn off with a slight

posterior slope, and exhibits an exposed tract of dentine.
13g

A thill, incoiispiciious basal ridge occupies the inner half of the liack part
of (lie crown ; a thicker festoon extends from the summit of the posterior
lobe externally to the bottom of the middle lobe ; and a short, prominent
ledge occupies the middle of the front of the crown.

The fore and aft diameter of the crown of the last lower molar is 1^ inches;
the transverse diameter in front is 14 lines; behind, 12^ lines.

Associated with the other specimens referred to Uiutatherium, there was
found the isolated tooth represented in Fig. 12, which I suppose to be a tirst
upper molar. It has the same constitution as the last upper molar above
described, but is smaller. In the present condition of the crown, the poste-
rior lobe is more prominent than the anterior, and it exhibits a broad horseshoe-
shaped exposed tract of dentine extending upon the summits of both lobes.
The dentinal surface is concave from side to side, and inclines forward. The
outer extremity of the anterior lobe, broken in the specimen, is considerably
thicker than that of the posterior lobe. Back of the inner conjunction of the
lobes, just below the summit, the rounded tubercle is visible, such as exists
in a corresjionding position in the last molar. It is worn so as to exhibit a
small circular islet of dentine.

The basal ridge, as in the last upper molar, is thick in front and behind,
but feeble upon the inner and outer sides.

The first molar was inserted by a pair of fangs. The antero-posterior
diameter of the crown is 16 lines ; the transverse diameter at the hinder lobe
is 15i lines.

The upper molars of Uintatherium above described, bear considerable
resemblance to the last upper molar of Lophiodon lidrisiense, as represented
in Fig. 3, Plate XVII of Gervais's Paleontologie. They differ especially in
the absence of the offset from the middle of the anterior part of the front lobe
of the crown.

The upper molar teeth, attributed by Gervais to L. parisicm^e, represented
in his Figs. 3, 4, so nearly resemble the corresponding teeth of Uintatherium
and so decidedly differ from those of Lophiodon, as characterized from the
typical species L. isselense, that it may be questioned whether it belongs to
the same genus. The characters presented by the teeth referred to L. parisi-
ense, are suthcicntly distinct and well marked to consider them as indicating
a genus differing from Lophiodon and Uintatherium, and probably more nearly
related with the latter than the former.

9!)

The cranium of Uiiilaihcruiiu, represented in Fig. 1, Plulc XXVI, is of
rcnuirkablc form and unlike tliat of any other known animal. The specimen,
though much mutilated, is yet sufficiently well preserved to give us sonic
notion of the peculiarities of the skull.

The top of the cranium presents a deep basin-like concavity separated on
each side from the temporal fossfe l)y a wide projecting crest. The entire
extent ot" tliis cannot be determined from the broken condition of its edirc in
the specimen, l)ut on one side it projects obliquely outward and upward for
three inches beyond the inner surface of the temporal fossa. Posteriorly, the
crest is continuous with a thick broken border extending across the top of
the occiput so as to make it api)ear as if the lateral projections of the
cranium were continuous behind. The depth of the supra-cranial hollow in
the specimen is upward of several inches, and was, no doubt, greater in the
complete skull.

The temporal fossa is a long deep concavity overarched by the wide lateral
crest separating it from the supra-cranial hollow. Its lower part spreads out-
wardly on a l:)road ledge extending from the lateral occipital border forward
upon the upper surface of the zygomatic root. This ledge resembles the
long extension backward of the zygomatic root in the bear, and in like man-
ner it projects over the auditory archway and the contiguous processes.

From the fractured condition of the specimen, I am unable to ascertain the
])osition of the squamous suture, and this may be said also of other sutures.
The temporal surface as formed Ijy the squamosal plate and the iieighb(jring
portion of the parietal is pierced with a number of large vascular foramina.
The occipital surface is broad, and it slopes inwardly from above to the occi-
pital foramen.

The large condyles project strongly backward and downward, and are not
in the least degree sessile, but well defined from the occipital surfiace by a
deep groove. Their articular surface is broad, being within a fourth as great
as the depth, and the flexure near its middle appears less pVonounced than
usvial. The articular surfaces are not prolonged below on the basi-occipital,
and the condyles in this position are separated by a deep notch twenty lines
from each other.

The basilar process is broad and thick, and moderately tapering. Its undcM-
surface is transversely convex, especially antericn-ly. On each side ol tlie
middle it presents a broad rough eminence for muscular attachment.

100

The relative positions of the paramastoid and mastoid processes, the audi-
tory archway, and the post-glenoid tubercle are nearly the same as in feline
animals, but here the resemblance ceases.

The paramastoid process is a comparatively slight roughened eminence,
situated just above and external to the position of the fore part of the con-
tiguous condyle. It is separated from the mastoid process by an archway
directed inward and forward to the space usually occupied by a tympanic
bone, but whicli in the specimen is filled with the matrix of the fossil.

The mastoid process, though much broader and longer than the paramastoid,
does not project so much downward as the occipital condyle. It is semicir-
cular below and roughened, and is compressed from without inwardly. Its
outer surface presents a median fossa at the base.

The auditory archway expands outwardly in a funnel, and below is
partially contracted by a short ledge, a process of the tympanic, projecting
from the mastoid process.

The root of the zygoma is of great strength, and has, projecting downward
from it, a post-glenoid tubercle of extraordinary size. The process is 2^
inches in width, and projects externally in a rounded knob. Its lower part
forms a slightly irregular flat sfirface, just above which, the tubercle is 1^
inches thick. Its inner extremity slopes upward and inward.

The glenoid articulation is transverse, and its surface straight in this direc-
tion. Upon the post glenoid tubercle the surface is vertical until it curves
for\yard and upward to the anterior edge of the zygomatic root. Its forward
extension is about equal to that downward. The glenoid articulation is evi-
dently adapted especially to a hinge-like motion, though not so restricted as
that of carnivores.

Measurements derived from the cranial specimen of Uintatherium are as
follows :

Incbcs.

Breadth of the craDium at the outer part of the post-glenoid tubercles 10

Breadth of the crauium at the mastoid processes 7^

Width of the basi-occipital in front of tbe occipital condyles 2^

Breadth of the occipital condyles together C

Breadth of each coud\ le 2^

Depth of each condyle 3

Distance between the condyles or breadth of the occipital foramen 2J

Length of the temporal fossa fore and aft ■ 7

Breadth of crauium between the temporal fosste where deepest, about . -tj

Depth of cranium from bottom of supra-cranial basin to basi-occipital, about 4J

101

The lower-jaw specimens of Uintatlierium are represented in Fijr. 11,
^late XXV, and Figs. 32, 33, Plate XXVII. Both contain the last molar, and
the better-preserved one also contains the fangs of the preceding molars and
the last premolar. The space occupied by the molars is 4 inches, which
appears small in relation with the size of the animal. The space which was
occupied by the second molar is nearly as broad as the last molar. The
crown of this measures li inches. The space which was occupied hy the
first molar is little more than three-fourths of an inch, thus showing a great
difference in the size of the first, compared with that of the succeeding
molars.

The body of the jaw is of robust proportions. Its depth beneath the fore
part of the last molar is 3^ inches ; its thickness just above the I'ounded base
is nearly 1^ inches. A strong obtuse ridge sweeps from the root of the coro-
noid process downward and forward along the base of the jaw beneath the
position of the molars.

Back of the position of the latter, the jaw bears more resemblance to the
corresponding portion in the great felines than it does to that of ordinary
pachyderms.

The coronoid process is a broad curved plate rising immediately in advance
of the condyle, as in the lion. As in the latter, likewise, it is impressed ex-
ternally with a deep masseteric fossa extending below on the body of the
bone, but becoming more abruptly shallow approaching the base.

Tlie entrance to the dental canal is nearly on a line with the alveolar bor-
der, 2^ inches above the base of the jaw.

The condyle is a transverse convexity 2^ inches in breadth, and rather
more than an inch in width at the middle. It is narrowest internally, the re-
verse of the condition in the lion.

The breadth of the jaw back of the molars is estimated to be about 5
inches ; the breadth of the coronoid process at base is about 3 inches.

The specimen of a mutilated atlas, represented in Fig. 2, Plate XXVI, and
Fig. 34, Plate XXVII, supposed to belong to Uintatherium, was found by
the writer on the buttes west of Dry Creek Canon. It accords in size with
the cranium of Uintatherium above described, and fits the occipital con-
dyles as well as the bone of one individual might be expected to adapt itself
to that of another.

The atlas is very unlike that of any ordinary familiar animal. While it is
much smaller than that of a mastodon, it includes a canal of even greater

102

capacity. Unlike tliat ot" tlie animal just named, it is quite circular, and
about 3J inches in diameter. The portion occupied by the spinal cord is
absolutely larger than in the mastodon, and it is but slightly defined, from the
portion for the pivot of the axis, by slight tubercular elevations for the trans-
verse ligament.

The atlas is proportionately longer than in the mastodon, but is of less
width. The inferior arch beneath is nearly flat, and without a hypapophysis,
and on each side presents a superficial, rough prominence ["or muscular
attachment. The neural ai'ch is comparatively long and narrow, and appears
to be devoid of a protuberance.

The articular concavities for the occipital condyles are deeper and more
strongly sloping than in the mastodon. They are separated below by a deep
notch at the fore part of the inferior arch. Above, they are removed from
each other double the distance.

The articular facets for the a.xis are ovoidal, slightly concave, and incline
at an angle of nearly 45°. They are separated below for a couple of
inches by the thick back liorder of the inferior arch of the atlas. Above,
they are separated by the long semicircular edge of the neural arch.

The inferior arch of the atlas-supports a facet for the odontoid process of
the axis, which is distinct from the articular flxcets on each side of the latter.

The transverse processes are unlike those of the elephant and mastodon,
and are more like those in ordinary ruminants, &c. The ends are broken
off, but they appear as broad, thick plates, extending fore and aft, though not
the entire length in either direction.

The canal for the vertebral artery perforates the transverse jjrocess fore
and aft from the back half of the upper to the anterior part of the lower sur-
face. As a groove, it then turns upward in advance of the root of the trans-
verse process, and is directed inward to a canal perforating the neural arch
anteriorly above the position of the articular concavities for the occipital
condyles.

Approximative measurements of the atlas are as follows:

IncbcB.

Breadth between the outer edges of the anterior articular concavities (>i|

Depth of the atlas posteriorly from above downward 4.J

Breadth between the outer edges of the posterior articular facets . . (>i

Fore and aft extent of the inferior arch at the middle li

Length of the atlas laterally 5

Diameter of spinal foramen from above downward 'A^

Diameter of spiual foramen transversely ' ^g

Breadth fore and aft of transverse processes , 3i

103

The hiunerus of Uinlatherium, of which the aiitorior view of a sprciinni
is given in Fig. 3, Plate XXVI, is very unlike that of" aii}' other tamiliar
animal. In its peculiarity of form it presents no very evident relationship
with that of the larger pachj-derms, odd or even t(jed, tlic proljoscideans, or
the ruminants. It is shorter, in proportion with its breadth, than in the
elephant. The shaft is narrowest and most nearly cylindroid at the union of
the upper two-thirds wilii the lower third. The upper part is prominently pro-
duced outwardly to support a long triangular deltoid tract, the point of which
reaches below the middle of the bone. The deltoid surface loolvs outwardly
and backward, and is nearly flat, except below where it is depressed. The
back of the shaft presents a broad, nearly flat surflice, dividing near the mid-
dle in two portions, of which one extends nearly straight downward, while
the other portion winds outward and forward below the deltoid tract to the
front of the distal extremity.

The surface of the shaft internally to the deltoid tract is wide and sloping
inwardly. It is slightly depressed on the deltoid expansion, but elsewdiere is
nearly flat transversely, and it narrows downward in its extension to tlie in-
ternal epicondyle.

The outer or greater tuberosity of the humerus and the contiguous portions
of the head and deltoid tract are destroyed in the specimen. The inner side
of the head of the bone presents a broad depressed tract rising on the shaft
Ijelow in a triangular protubei-ance, which answers to the ordinary internal
tuberosity of the humerus. From the apex of the angular protuberance, a
ridge descends the shaft defining the inner or anterior aspect of the bone
from the posterior.

The head is most convex from 1)efore backward, and in this direction it
looks as if, iu the complete condition, it had not been greater than the trans-
verse diameter.

The external epicondyle is thick and prominent, but is of comparatively
little vertical extent. Its summit forms a thick, rough eminence, extending
an inch externally to the capitulum and several inches in width above it. Its
outer face presents a l)road crescentoid surface directed obliquely outward
aiul downward. It is rougii and pierced with vascular foramina, and is
divided into several facets for the attachment of the extensors of the lore-
arm and the external lateral ligament.

The internal epicondyle is a comparatively low, thick, and rough pntnii-

104

nence, defined from the trochlea by a wide, pitted groove. Its upper part is
destroyed in the specimen. Its l>aclv part barely projects posterior to the
position of the trochlea.

Above the distal articulation, where the bone is expanded to form the outer
epicondyle, it is depressed into a l:)road and unusually deep concave fossa.

The olecranon fossa is broad and moderately deep, but is not much ex-
tended by the protrusion backward of the epicondyles.

The distal articulation of the humerus presents a well-rounded capitulum
on the outer condyle and a broad trochlea extending from it on the inner
condyle. The capitulum is convex and narrows behind on a ridge separating
the posterior prominence of the outer epicondyle from the trochlea. The
trochlear groove is directed obliquely from the fossa in front of the outer epi-
condyle downward and inward, then backward, upward, and outward to the
olecranon fossa.

The measurements of the bone are as follows :

Inches.

Length of the buinerus internally 20J

Width ti'ansversely of the head 4^

Width of shaft at the middle from the lower part of the deltoid tract to the pos-

tero-iiiteraal border i^

Thicl;ness of shaft at middle of same position 2^

Circumfereuce of narrowest part of shaft 9^

Diameter transversely of narrowest part of shaft 2g

Diameter autero-posteriorly of narrowest part of shaft 3

Breadth at the epicondyles , , , . - 7f

Breadth of distal articulation 5^

The mutilated upper extremity of the femur, represented in Fig. 4, Plate
XXVI, was found by Dr. Corson, on the buttes west of Dry Creek Caflon,
a dozen miles from the former specimens. It is suspected to pertain to Uin-
tatherium, though it would ajjpear to have belonged to a larger animal, and
perhaps a different species, than the one to wdiich the cranium and humerus
are referred. The specimen has about the same si^e and form as the corre-
sponding part in the elephant, but the great trochanter is destroyed. The
length of the fragment is about 11 inches. The head is 5 inches in diameter,
but its surface is too much mutilated in the specimen to determine whether
it possessed a jtit for the attachment of a round hgament, or whether it is
absent as in recent proboscideans. The outer border of the shaft below the
position of the great trochanter is 2g inches thick. From the appearance of

105

the specimen, tlie I'eimir in its entire condition luis evidently resembled that
of the elephant more than it does that of the perissodactyles.

The mutilated distal end of a femur, represented in Fig. 5, is also supposed
to belong to Uintatherium, though it did not pertain to the same individual as
the preceding specimen. It was found in the same locality, but at a distance
from the former, and was derived from a different stratum, as it has an adher-
ent friable sandstone matri.x, while the other has an adherent indurated clay
matrix. It is considerably smaller than the corresponding part of the femur
of the elephant, and is very different in anatomical character. It is propor-
tionately less thick. The shaft above the articulation, on the front and at the
sides, presents a continuous transverse convexity, without any depression
whatever above the position of the trochlea. The posterior surface in the
same direction, between the position of the low epicondyles, is concave.

The loss of part of the outer condyle prevents a comparison of Ijreadth
with the inner one, but this is more prominent posteriorly than the former.
The trochlea is shallow and but feebly prominent anteriorly in comparison
with that in the elephant. Its articular surface is continuous with that of
the inner condyle, and also that of the outer one, so far as it is preserved in
the specimen, without the slightest definition. The intercondyloid notch
commences at the bottom of the trochlea and gradually widens backward and
upward with a curve outward.

The length of the fragment of the femur is 6^ inches. The breadth be-
tween the epicondyles is about 5 J inches ; the thickness of the inner condyle
and trochlea together is 5 inches, and the depth of the trochlea along its
groove is 2J inches.

Several large tarsal bones, found together on the buttes to the west side of
Dry Creek Canon, may perhaps belong to Uintatherium. They consist of a
calcaneum, astragalus, and cuboid bone of the left foot, and fit well enough to-
gether to have belonged to the same individual. In form and 2)roportions,
though somewhat peculiar, they more nearly resemble those of tlie mastodon
and elephant than of other known animals.

The calcaneum, of which an upjjer view, half-size, is given in Fig. 6,
Plate XXVI, is remarkable for its short robust character. The tuber calcis,
in comparison with that in the ordinary proboscidians, is very short. The
breadth of the tuber exceeds its length, and the depth exceeds the breadth.
The thickened extremity narrows below and is continuous with the thick
longitudinal plantar ridge. The upper part of the tuber inclines nearly
U u

lOG

slj-aiglit I)ackwar(l I'rom tlie articulation. Its outer surtace l()rms part of an
irregular plane with the fore part of the boue.

The sustentaculum is thick and three-fourths the length of the bone. Tlie
groove beneath for the flexor-tendons is well marked. Tlie articular surface
it supports for the astragalus, is larger than that on the body of the bone.
The groove separating the articular surfaces for the astragalus nearly occu-
pies the middle of the bone Both surfaces are flat in front, but convex back-
ward behind

No articular surface exists for the fibula. At the fore part of the bone
there is a small articular facet for the cuboid. The remaining portion of the
front surface forms a deep and wide irregular plane.

The astragalus, of which upper and lower views are given half-size in
Figs. 7, 8, Plate XXVI, resembles that of the ordinary proboscideans. The
bone is irregularly square, with nearly equal horizontal diameters, and of less
thickness than these.

The ui)per articular face has nearly the shape of that in a mastodon, but
is rather more depressed posteriorly. The fibular extension holds about the
same proportion to the tibial surface as in the animal named.

The calcanean articular surfaces are the reverse in their comparative size
to what they are in the mastodon, the inner one being the larger. Both are
also more concave fore and aft than in that animal.

The navicular articular surface is proportionately deeper in comparison with
its width tlian in mastodon, and is well defined outwardly from the cuboid
articular facet.

The cuboid is triangular in outline, with rouiraed angles, and with the
thickness more than iialf the breadth or depth. Proximally it presents a
double articular facet, of which the division for the astragalus is larger than
that for the calcaneum. The former division is continuous with a narrow
fiicet on the inner side for the navicular. Distally the l)onc also presents a
doulile articular tiicet, the divisions forming an obtuse angle.

The measurements of the tarsal bones are as follows:

Calcaneum,

Lines.

Length of calcaueum 413

Breadth at fore part 39

Depth at fore part externally 31

Length of tuber c.ilcis from the outer articular facet above . l-'O

Breadth transversely of the outer articular facet for the astragalus 14A

107

Li Ilea.

Breadth fore ami aft of the outer articuhir facet for the astragahis 'S3

Breadth trausverselj^ of the iuuer articular facet for the astragalus . . , 18

Breadth fore and aft of the inner articular facet for the astragalus 2i

Breadth transversely of the articular facet for the cuboid 14

Breadth vertically of the articular facet for the cuboid 10

Astragalus.

Lines.

Greatest breadth fore and aft of the astragalus at inner side uO

Greatest breadth transversely of the astragalus 52

Greatest thickness of astragalus 32

Breadtli of tibial articular surface at niidillo transversely ' 38

Breadth of tibial articular surface at middle fore and aft 32

Breadth of articular facet for scaphoid 40

Depth of articular facet for scaphoid 28

Cudoid.

Linos.

Depth of the cuboid 25

Breadth of the cuboid interiorly 25

Length of the cuboid at center 15

The canine tooth, originally described and referred to a carnivore with the
name of Uintamastix atrox, is represented in Figs. 1 to 3, Plate XXV. T
specimen is broken into two pieces, is mutilated at the point, and has lost
apparently several inches of the base. In its perfect state the tooth approxi-
mated a foot in length, of which it now retains about three-fourths. It is saber-
like in general form — long, laterally compressed cyliudroid, and moderately
curved. It appears more curved at the base, and from this position, also, has a
somewhat outward deflexion, so that the tooth in its course curved forward and
downward with an outward divergence. Laterally from the base it gradually
tapers to the point ; fore and aft it gradually narrows to near the lower third,
when it becomes slightly expanded before tapering, so as to assume the shape
of a lance-head. This likeness is rendered more striking internally by the sur-
face being concavely impressed in front and behind the axis extending toward
the trenchant borders of the lance-head extremity. Externally, it is impressed
in like manner to a less extent posteriorly, but not anteriorly. Above the
lance-head extremity of the tooth it is obtusely rounded in front and Ijehind,
and in this position is eUiptical in transverse section, as represented by tlie
(ludine, Fiir. 5. A section near the middle of the lance-head extremitv has
llie form represented in Fig. 4.

The tooth, so far as tlie specimen extends, appears to have been invested
willi thin enamel throughout. Externally, if reaches lo the broken edge of

108

the base, and, internally, appears to liave been lost from the corresponding
position l)y erosion. Externally, it is longitudinally rugose, and the rugosity
appears to be greater toward tlie point, and, to some extent, is divergent
toward the trenchant borders. Internally, the rugosity of the enamel is less
marked, and toward the point it is worn off for several inches along the axis
and near the borders from the attrition of an opposing lower tooth. The ex-
tent of attrition would apparently indicate large lower canines.

At the broken base of the specimen the borders of the exposed pulp cavity
are nearly 4 lines thick. The fore and aft diameter of the tooth 2 inches
below the broken base is a little under 2 inches ; the thickness is 13 lines.
The breadth of the tooth just Ijefore expanding in the lance-head extremity
is 1^ inches. The widest part of the latter appears to have been a couple of
lines greater.

The tusk above described, though apparently according in form with those
of Dinoceras mirabiUs, as described by Professor Marsh, exhibits different
proportions, having less breadth and greater thickness. Thus Professor
Marsh gives as the diameters of the tusks of D. mirahilis 64 millimeters
breadth, and 25 millimeters thickness. The tusk above described has a
breadth of 50 miUimeters, and a thickness of 28 millimeters.

From the description of the skull of Dinoceras given by Professor Marsh,
as before intimated, I have been led to view the large tusks above described,
and originally referred to a carnivore with the name of Uintamastix, as really
pertaining to Uintatherium, and perhaps to the same species as that indicated
by the cranial specimen referred to TJ. rohustum.

The molar tooth of Uintatherium, represented in Figs. 13, 14, found with
the large tusk, has the same form and constitution as the upper molars first
referred to the genus, except that it is considerably smaller, and has no
tubercle behind the summit of the conjunction of the lobes of the crown.
Proportionately, also, the basal ridge is much better developed at the inner
part of the crown, where it is continuous with the stronger ridge in front and
behind. The antero-posterior diameter of this tooth is 11^ lines, and its
transverse diameter is estimated at 13J lines.

The tooth I supposed to be an upper premolar of U. rohustum; if, how-
ever, it is a true molar, its comparatively small size, and the absence of the
characteristic tubercle on the posterior slope of the conjunction of the lobes
of the crown, as existing in the species just named, would indicate that it

109

probably belonged to a diflereiit one. Found in association with the canines
referred to TJintamastix atrox, it may pertain to the same animal.

Order Rodentia.

Small qnadrupeds with clawed toes. Teeth consisting of two long curved
incisors in each jaw ; no canines, and the molars separated from the former
by a wide interval.

Paeamys.

An interesting peculiar extinct genus of gnawers of the sciurine family is
indicated by a number of specimens, consisting of fragments of lower jaws
with teeth, which were discovered by Dr. Carter, in the summer of 1871, in
the Tertiary formation in the vicinity of Fort Bridger.

As in the squirrels and marmots, the lower molars are four in number,
and are inserted each by two fangs. They are nearly of the same size, but
are proportionately narrower than in the animals just mentioned, as the fore
and aft diameter exceeds the transverse, while in most sciurine animals the
reverse condition usually exists.

The crowns are short, square, tuberculate, and enameled. The arrange-
ments and proportionate size of the tubercles at the four corners of the crown,
including a concave surface, are the same as in the squirrels.

The lower jaw is proportionately shorter and deeper than in most known
rodents, the reduction in length being mainly due to a less development of
that part of the bone in advance of the molars. To compensate for the dif-
ference in length and to make room to accommodate the incisors, these teeth
reach farther back than usual. In squirrels and marmots their posterior
extremity reaches a short distance behind and beneath the last molar. In
Paramys it reached further backward, upward, and externally to a level
with the crown of the last molar.

The jaw in advance of the molars is not only short compared with the usual
condition in most known rodents, but the acute edge of the hiatus between
the molars and incisors is almost on a level with the alveoli of the teeth,
instead of forming a deep concave notch, so conspicuous a feature in the lower
jaw of the gnawers generally.

In sciurine and most other rodents the ridge defining the masseteric fossa
extends far forward on the side of the jaw to a position beneath the second or

even the first molar tooth. In the rabl)U>; tlic defining ridge is comparatively
far back, extending only to the position of the interval of the last two molars.
In Paramys it holds an intermediate position, extending as far forward as the
position of the third molar, where it forms a conspicuous angular prominence,
as in the marmots.

The mental foramen, much higher in relative position than usual in rodents,
is situated in advance of the molars a short distance below the edge of the
hiatus separating the latter from the incisor.

Paramys delicatus.

The largest species of Paramys was, perhaps, about a fourth less in size
than the Maryland marmot, though its series of molar teeth is nearly equal
in size, measuring three-fourths of an inch in length. It is represented by
two specimens sent to me by Dr. Carter, consisting of portions of the right
and left sides of the lower jaw, containing most of the molars and portions of
the incisors. One of them is represented in Fig. 23, Plate VI, of the natural
size. The triturating surfaces of the molars of both specimens, magnified
three diameters, are represented in Figs. 24, 25.

In one of the specimens. Fig. 23, two mental foramina exist, one in the
position, previously indicated, in advance of the molars, a short distance
below the edge of the jaw ; the other is situated lower down below the posi-
tion of the first molar. In the other specimen the foramen exists in the lat-
ter position, and as the jaw is broken in advance, it cannot be determined
whether a second existed, which is, however, probable, as it is the usual and
normal position of one. A prominent tubercle is il)rmed at the angle of con-
vergence of the ridges which define the masseteric fossa.

Paramys delicatior.

A second species is indicated by a specimen consisting of the greater por-
tion of the left ramus of a lower jaw, represented in Fig. 26, Plate VI. It
retains the second molar tooth, the triturating surface of which, magnified
three diameters, is represented in Fig. 27 of the same plate. The molar
series has measured about 74 lines in length, and (he animal was about the
size of our common grav rabbit.

Since writing the above, I have x'eceived from Dr. Carter several additional
specimens which I suspect belong to the same species. One of them, an in-
termediate lower molar, is represented in Fig. 16, Plate XXVII. It suflS-

Ill

cinifly resembles the foolli oi" Fig. 27, Plato YI, origiuiilly reteried lo /'.
delicatior, to pertain tt) tlu; same species, thougli it is slightly larger.

The other specimen, apparently from the same individual, consists of a pair
of upper molars represented in Figs. 17, 1<S, Plate XXVII, magnified three
diameters. They have nearly the form and construction of those of the
Sciurides.

The fore and aft diameter of the lower molar is 1.8 lines. The fore and
aft diameter of the upper molars is 1.8 lines, and the transverse diameter is
2 lines.

Pakamys delicatissimus.

A third and still smaller species of Paramys is indicated liy a specimen
consisting of the greater portion of the right ramus of a lower jaw contain-
ing all the molars, and a second specimen consisting of a small fragment of
another lower jaw containing the second molar. The first specimen of the
natural size is represented in Fig. 28, Plate VI. A view of the triturating
surfaces of the molars, magnified three diameters, is given in Fig. 29. The
molar series measures J an inch in length, and the animal was about the size
of the common gray squirrel.

Comparative measurements are as follows :

Leugtb of louver molar series

Leiigtb of biatus iu advance of lower molar series

Deptb of jaw below tbe second molar

Fore and aft diameter of incisor

Transverse diameter of incisor

Fore and aft diameter of second molar

Transverse diameter of second molar

P. (lelica-
tus.

Lines.
9

-1
5

p. delica-
tior.

Lines.

P. delica-
tissimiLs.

Lines.
G

•1

H
n

MYSOPS.

Mysops minimus.

A small rodent, intermediate in size to the common mouse and the brown
rat, is indicated by a specimen discovered by Dr. Carter at Grizzly Buttes
and sent to the author last summer. The S])ccim('n cousists of the median
portion of the right ramus of a lower jaw containing the last two molars, the

112

fangs of the others, and part of the incisor. It is represented in Fig. 31,
Plate VI, magnified two diameters.

The jaw in its form, proportions, and construction, and the number of teeth
and their relative position, agree with the conditions in Paramys, but the form
of the molars is sufficiently different to refer the specimen to a different genus,
for which the above name has been proposed.

The molar teeth, as in Paramys, are four in number, inserted each by
a pair of fangs. The crowns are quadrate and invested with enamel.
The triturating surface, instead of being constructed like tluit of the squir-
rels, is more like that of the rats, as seen in Fig. 32, Plate VI, in which
tiic last two molars of the specimen are represented magnified eight diam-
eters. The crown of the third molar exhibits two transverse lobes, or
ridges, joined by an intermediate narrow ridge, and the inner extremities of
the lobes include a trilateral tubercle. The enamel being worn away from
the prominences of the crown leave exposed a pair of transversely eUipsoidul
dentinal surfiices joined by a narrow isthmus. Upon the summit of the inter-
nal tubercle a small islet of dentine also appears.

The last molar exhibits three transverse ridges or lobes, of which the
anterior is the thickest, the middle one the thinnest, and the .i^osterior the
shortest. The anterior lobe is worn so as to exhibit a transversely elliptical
surface of dentine bordered with enamel. The middle ridge of the crown
appears sigmoid and is unworn. The posterior lobe presents an exposed islet
of dentine on the inner half of its length.

The anterior molar of Mysops, like the last one, is more elongate fore and
aft than the tw-o succeeding molars, but it is proportionately of less size than
in the rats, and has not three fangs as in these animals.

The length of the molar series is J of an inch. The first and fourtli
molars are about | of a line fore and afl ; the intermediate ones about ^. The
incisor measures about I of a line fore and aft l)y f transversely. The depth
of the lower jaw below the second molar is 2^ lines. The length of the
hiatus in advance of the molars is 1^ lines.

Mysops fraternus.

Since writing the foregoing I have received another specimen, which may
belong to Mysops. It was found by a Shoshone Indian, and given to Dr.
Carter. It consists of a portion of the right ramus of the lower jaw, repre-

113

scntrd iu Fig. 14, Plate XXVIl. It coiit;iiiis the last three molai-s, tlic trilii-
rating surtiices of which are represented in Fig. 15, magnified eight dianieters.

I'he jaw is proportioiaately deep and short, compared with that of Ihe ra1.
The masseteric fossa is deep, and defined by a rectangle, the apex of wiiioh
reaches as far forward as the position of the third molar tooth. The l)ordei-
of the jaw at the hiatus in advance of the molars extends nearly on a level
from their alveoli to that of the incisor.

The molar teeth, though having the same general constitution as the cor-
responding ones in the jaw-fragment of Mysops mini»ms, above described,
appear sufficiently distinct to pertain to another species, and I have therefore
distinguished it as such with the name of J/, fraternus.

In the jaw-specimens of both species the molars are worn nearly to the
same extent. In comparing the corresponding teeth, it will be seen that the
third molar in M. fraternus has a greater breadth fore and aft, and the last
molar is of more uniform width transversely. In both teeth the intermediate
conical lobe, occupying the inner part of the crown, is proportionately more
robust in M. frateimus.

The depth of the jaw below the third molar is 2.6 lines; the breadth ol'
each of the three back molars fore and aft is about eight-tenths of a line; the
space occupied by the four molars is a little over 3 lines.

SCIURAVUS.

In the American Journal of Science for July, 1871, Professor ]\Iarsh has
described an extinct genus of rodents from remains found at Grizzly Buttes,
under the aboTe name, and refers them to two species with the names of
Sciuravus nitidus and 8. undans. The former, described from an upper-jaw
fragment with three molars, was about the size of the brown rat. The latter,
indicated by a lower-jaw fragment with the incisors and the anterior three
molars, was a somewhat larger animal.

While we have not the means of determinmg whether Paramys is abso-
lutely distinct from Sciuravus, we have the opportunity of examining a speci-
men belonging to a different genus from the former, and which we suspect
pertains to the latter. The specimen in question consists of a fragment of the
left side of the lower jaw, containing the third molar, the alveolus behind, and
part of that in front. It belonged to an animal but little larger than the rat.
The fossil was found at Grizzly Buttes by Dr. Carter. The only remaining
15 G

114

tooth it contains is represented in Fig. 30, Plate VI, magniticd eiglit diam-
eters.

The tootli is al)oiit a line in breadth, and, together with the alveolns back
of it, occupies a space of 2^ lines. The crown of the tooth is quadrate,
broader than wide, and is composed of tour principal conical lobes, as in the
squirrels, and as in its associate Paramys The sculpture and connection of
the lobes is difTerent, as may be conveniently observed by comparing Fig. 30
with Fig. 27, representing a tooth of the same side of Paramys. It is espe-
cially to be noticed that in the latter the back pair of lobes include, between
them and the anterior lobes, a broad hollow, and the former are connected
behind by an acute ridge, which forms the posterior border of the crown.
The broad hollow of the latter is closed externally l:)y a festoon-like ridge
connecting the outer lobes at their base.

In the supposed tooth of Sciuravus (Fig. 30) the broad hollow of the crown
so conspicuous in Paramys and Sciurus is not evident. The posterior lobes
are conjoined by a transverse ridge, and are bounded behind by a thick ridge
descending inwardly from the postero-external lobe. The transverse valley
of the crown is occupied by a pair of ridges diverging from the postero-
external lobe to those in advance.

Order Carnivora.

PATRIOFELIS.

Pateiofelis ulta.

A carnivorous animal, rather larger than our common American panther,
and about the size of the jaguar, to wliicli the above name has been given, is
indicated by remains in the Bridgcr Tertiary formation. The sijecimens
from which it was originally described in the Proceedings of the Academy
of Natural Sciences for March, 1870, were obtained near Fort Bridger,
Wyoming, during Professor Hayden's exploration of 1869. They consist of
portions of both rami of a lower jaw, unfortunately with most of the teeth
lost or mutilated. The right ramus is represented, one-half the natural size,
in Fig. 10, Plate II.

The jaw of Patriofelis contains a series of five molar teeth immediately
succeeding the canine tooth without conspicuous interval, as in some of the
viverrine and musteline animals. The molar teeth arc all inserted Ijy a pair
of fangs, and none of them appear to be of the jmrely tubercular kind. The

115

first of" the series is smallest, and the third the largest ; the i()urtli was inter-
mediate ill size to the latter and the last one, which little exceeded tlie
second.

The crown of the last molar in the specimen appears as if it had been
composed of an anterior pointed, or perhaps trenchant, lobe, and a large pos-
terior heel.

The crown of the penultimate molar appears to have been nearly of the
same character. In the crown of the antepenultimate molar the posterior
heel forms a median acute ridge from which the sides slope toward the
bottom. The outer slope, nearly twice the depth of the inner, is bounded
behind by a ridge descending from the summit of the heel. The inner slope
is bordered by a basal ridge curving downward and forward from the summit.

The canines, as indicated by portions of the alveoli, are large and powerful
teeth, as in feline animals. The alveoli are about ^ i'lch in diameter.

The jaw has nearly the same form as in the panther, but is proportionately
shorter, and beneath the molar teeth of greater depth, in this respect resem-
bling more the condition in the striped hyena. The condyle has the same
form and relative position as in ordinary carnivora, but is thicker or of greater
extent on its articular surface fore and afl than in the panther. Its compara-
tive breadth is undeterminate, from its being broken at both ends in the
specimen.

The back portion of the jaw is proportionately narrower than in the
panther; and the coronoid process, which appears to have had the same
f(jrm as in this, is likewise narrower. The masseteric fossa is not so deep as
ill ordinary carnivora. Extending from the coronoid downward, a little
below the level of the condyle, it becomes, rather abruptly shallower, and
from this position gradually lessens in depth toward the base, from which it
is not abruptly defined by a narrow ridge, as in the ordinary carnivora.

The symphysis is strong, and the rami approaching it thick, as in the
pantlier. A group of seven mental foramina occupy a position at the side
of the symphysis. The largest of them, as in the panther, is situated outside
the back part of the canine alveolus.

From the absence of the chai'acteristic portions of the teeth, the exact
relationship of Patriofelis is not clear. It is perhaps intermediate to the
feline and canine animals.

116
Measurements from the lower jaw of Patriofelis uUa are as follows :

Inches. Lines.

Estimatetl length of jaw 6 0

Distance from back of condyle to canine alveolus 5 4

Distance from back of condyle to back of last molar 2 3

Space occupied by the molar series .3 0

Breadth of coronoid at base 1 7

Depth of jaw below penultimate molar -. 1 -i

Depth of jaw below back of last molar 1 6

Measurements of the molar teeth, estimated from their fangs and alveoli,
are as follows :

Lines.

Breadth of first molar tooth 5

Breadth of second molar tooth , 7

Breadth of third molar tooth 8J

Breadth of fourth molar tooth 7

Breadtli of tifth molar tooth 8

Fig. 20, Plate VII, represents a tooth discovered by Dr. Carter near Fort
Bridger. It appears not to belong to the lower jaw of Patriofelis, but pci'-
haps belongs to the upi)er jaw. The crown is composed of a large conical
lobe with a broad heel, the sides of" which slope from a median ridge. The
breadth of the crown is 8^ lines ; its thickness 5 lines.

SINOPA.

SiNOPA EAPAX.

A lower-jaw fragment, containing two teeth and portions of two others,
represented in Fig. 44, Plate VI, appears to indicate an extinct genus related
to the canine family. The specimen was discovered by Dr. Carter in the
vicinity of Fort Bridger, and was by him presented to the writer. It belonged
to an animal about the size of the gray fox.

The specimen is insufficient to ascertain with any certainty the exact rela-
tionship of the animal to which it belonged, but the character of the teeth
leads me to view it as having held an intermediate position to the existing
genus Canis and the extinct one Hysenodon.

Tlie teeth preserved entire in the specimen appear to correspond with the
last premolar and the first or sectorial molar of the fox, and the remains of
two teeth behind would be of the second and third molars. The last pre-
molar is larger than the molars. Its crown is as wide, but is longer than that
of the tooth retained behind it. The form of the crown is more like that in

117

Hyaenodoii (iiaii in th(3 fox. It is prnportioiiafcly longer and narrower than
in the latter, and the accessory cnsp at llic back border of the principal oiie
in the tijx is nearly obsolete in the fossil. The heel of the cro.wn is l)etler
developed than in the fox. It forms a median acntc ridge, and slopes off on
each side to the rounded base of the crown.

The first molar, as liefore intimated, is smaller than the last premolar. It
is as wide as the second molar, but not so thick, and is slightly wider than
the last molar. It is proportionately better developed in its relation with the
succeeding molars than in Hyasnodon. Its crown is intermediate in form
and in the development of its parts to that in the fox on the one hand and the
raccoon and badger on the other. The fore i)art of the crown, consisting of
rather more than one-half, corresponds withthe sectorial ])orti()n of the same
tooth in the fox, but accords more in shape and the relative position and de-
velopment of its points with the homologous portion in the raccoon and bad-
ger. The heel of the crown is bordered by a horseshoe-shaped ridge inclos-
ing a cup-like concavity.

The heel of the second molar, the only portion of the crown retained in
the specimen, is stouter than in the first molar, liut has the same shape. The
width of the crown is about equal to that of the tooth in advance, but has
been slightly thicker.

The last molar is a two-fanged tooth like those in advance, but is not quite
so wide, and a small portion of the back of the crown indicates it to have
been of less thickness.

The base of the jaw-fragment is broken away in the spcchnen. The por-
tion preserved presents nothing peculiar.

Measurements of the fossil are as follows :

Lines.

Space occupied bj- the last premolar and molars 15

Space occupied by the molars 11

Breadth of crowu of last premolar 4

Length of crown of last premolar at middle 3J

Breadth of crown of first molar 4

Length of crown of first molar at principal cusp 2i|

Thickness of crown of first molar at heel 2

Breadth of crowu of second molar 4

Tliickuess of crown of second molar at heel 2^

Breadth of crown of last molar i! J

The name Sinopa, applied to the extinct genus, according to Professor
Ilayden, is aboriginal, and is applied by the Blackfeet Indians to a small fo.x

118

While the original notice of Sinopa rapax was in print, in the Proceedings
of Ihe Academy of Natural Sciences of Philadelphia, Professor Marsh pul)-
lished a description, in the American Journal of Science for 1871, of some
remains of a carnivore from the vicinity of Fort Bridger, under the name of
Vulpavus palustris. It is characterized from several upper molars which accord
in size sufficiently to pertain to the same animal as that above described.
Further researches may prove the two animals to be the same.

Sinopa eximia.

A jaw-fragment, discovered by Dr. Carter at Grizzly Buttes, and repre-
sented in Fig. 45, Plate VI, belongs to a smaller carnivore than the preced-
ing. It was probably allied to the former, and may perhaps pertain to a
smaller species of the same genus, of which I have some doul)t, though, in
the absence of more confirmatory evidence, I have considered it as such.

The specimen contains two teeth, which sufficiently resemble those re-
tained in the jaw-fragment referred to Sinopa rapax, as to render it probable
they are the corresponding ones, though the contiguity of the symphysis leads
me to suspect that they may be the last two premolars. As seen in the
figure, the back of the symphysis is just below the position in advance of
the first tooth of the specimen. The teeth in shape are nearly like those in
Sinopa rapax, but the proportions are reversed. The crowns of the two
teeth have the same length, but the hinder one is wider and thicker.

The measurements of the specimen are as follows :

Lines.

Depth of the jaw below the teeth 4|

Space occupied by the two teeth 4J

Width of the crown of the first tooth 2

Length of the crown of the first tooth 2:^

Width of the crown of the second tooth 2J

Length of the crown of the second tooth 2^

UINTACYON.

UlNTACYON EDAX.

An interesting fossil, recently received from Dr. Carter and discovered by
him in the Bridger beds, consists of the greater portion of the right ramus of
a lower jaw, represented in Fig. 6, Plate XXVII. The specimen indicates
a carnivorous animal, probably marsupial, and of a hillierto unknown genns,
for which the above name has been proposed.

119

The jaw contained a series of eight inohir teeth and a canine separaled
I'rom the former by a small hiatus. Of the molar teeth, the specimen retains
))art of the first molar and the succeeding molar, represented in Figs. 7, H,
and the intermediate three premolars represented in Figs. 9, 10.

The jaw-fragment agrees in its form and proportions with the correspond-
ing part in the existing fox. The teeth also, so far as they are preserved, are
nearly like those of the latter animal.

The canine tooth was equally well developed as in the latter, and the first
premolar is inserted by a single fang. The second premolar likewise resem-
bles the corresponding tooth of the fox.

The third premolar is peculiar, and perhaps anomalous. It resembles niore
the form of an upper pi'emolar than the nsual form of lower premolars. It
has three fangs, of which two are inserted in a line with those of the con-
tiguous teeth, while the third fimg is external. The crown is a four-sided
pyramid with projecting basal angles, of which the postero-internal one is the
most prominent.

The fourth premolar is like the last one of the fox, Ijut is proportionately
thicker. The fifth premolar is lost, and, like the preceding tooth, was inserted
Ijy a pair of fangs.

The first molar has lost the fore part of its crown, and this appears not to
have been proportionately so well developed as in the fox. The crown of
the second molar is nearly of the same form as in the latter.

The last molar is a small tooth, as in the fox, and is also inserted by a single
fang.

The measurements of the specimen are as follows :

Lines.

Depth of lower jaw at second premolar 4. 8

Depth of lower jaw at first molar 4. .S

Distance from fore part of caniue to back of last molar IS. 0

Length of the molar series 14. 8

Length of the premolar series 8. 8

Length of the true molar series (J. 0

Breadth of second premolar 1-7

Breadth of third premolar 1-5

Breadth of the fourth premolar 1- *•

Breadth of the fifth premolar ^-4

Breadth of the first molar >5. ^

Breadth of .second molar ^- "

Breadth of third molar t • "

The main peculiarity of tlie fossil is the presence of an eighth tooth to the

120

molar series. The one in excess ul' the usual nunil)er, witliuiit other considera-
tion tlian convenience, I have viewed as a premolar. From its anomalous, or at
least unusual, torni, the tburth of the series of the premolars may l»e regarded
as the additional tooth. Without it, the jaw would indicate a small canine
animal, or at least a species of a closely allied genus. The animal was al)out
half the size of the common fox.

UlNTACYON VORAX.

Perhaps a larger .species of the genus just named is indicated by the jaw-
fragment represented in Fig. 11, Plate XXVII. The specimen was obtained
on Henry's Fork of Green River, during Professor Hayden's expedition of
1870.

The jaw-fragment agrees in form with the corresponding part of the jaw-
specimen of U. edax, but from its proportions belonged to an animal twice the
size. It contains the penultimate molar, the heel of the one in advance, and
the alveolus of the last molar. The teeth agree in their proportions witli
those of U. eda.r, and the penultimate molar, represented in Figs. 12, 13,
sufficiently resembles that of the latter to belong to the same genus. The
l>ri-atllh of the penultimate molar is 2|- lines.

Order Tnsecfirora.

OMOMYS.

Omomys Caeteri.

The first mammalian fossil described from the Bridger Tertiary beds con-
sists of the fragment of a lower jaw with teeth, discovered by Dr. Carter on
Twin Butte, about one mile from Fort Bridger. The specimen is repre-
sented in Figs. 13, 14, Plate XXIX, of ''The Extinct Mammalian P'auna
of Dakota and Nebraska," published as the seventh volume of the Journal of
the Academy of Natural Sciences of Philadelphia tor 18G9, and is described
on page 408 of that work.

The jaw-specimen was accompanied with tVagments of the cranium, for the
most part too much broken to determine anything from them. They would
appear to indicate a skull about the size of that of the common weasel, but
with weaker jaws.

A fragment of the cranium retains a straight linear sagittal crest al)out 14

121

lines in lenglli to its l)il'iircatioii at \\\r lorcliead. 'riic loinpural siirfacps
appear to be full and convex, as in the weasel.

An occipital condyle resembles those of the latter, and measures about 1
lines in its longer diameter.

The ramus of the lower jaw, compared with that of the weasel, is more
slender and delicate in its proportions. In the specimen both extremities
are broken, but a portion of the sym])hysis is still retained.

The jaw below the molars is of nearly uniform depth, and measures about
2 lines. The base is slightly convex fore and aft, but makes a concave turn
toward the angle. The masseteric fossa below is well marked. A small
mental foramen occupies a position below the antepenultimate premolar.

In the earlier description of the specimen, I remarked that seven molar
teeth, in an unbroken series, appear to have occupied the side of the jaw. In
the actual condition of the fossil there are four teeth, consisting of the anterior
two molars and the two premolars in advance. In front of these there are
two empty sockets and parts of two others, and behind them there are the
imperfect alveoli for a third molar. The sockets at the front of the jaw I at
first supposed were intended for two additional two-fanged premolars. They
fill up the interval between the retained teeth and the edge of the symphysis
so closely that, from this fact and their relative size, I now suspect that they
may have been occupied by a single-fanged premolar, a small canine, and
two incisors. Assuming that such was the case, without any certainty in the
matter, the number of molar teeth in the series would be six, of which three
were premolars and three true molars. In this view the teeth retained in
the specimen consist of the second and third premolars and the first and sec-
ond molars. Their constitution would appear to indicate an insectivorous
animal which, jjerhaps, was marsupial in character.

The teeth successively decrease in i)rominence or height from the second
premolar to the second molar. They resemble in constitution the corre-
sponding teeth of the opossum.

The crown of the premolars is laterally compressed conical, thicker behind
than in front, and is embraced by a basal ridge. The crown of the second
premolar, more prominent than in any of the other teeth, is triangular, longer
than broad, and sharp-pointed. Its anterior slope is slightly convex and acute;
its posterior slope is longer, slightly concave, and wide. The basal ridge
ibrms an excavated heel behind, a more elevated ledge in front, and a jiair of
IG G

122

t'estooiiR both intcrnall}' and extemall\'. The inner side of the crown is
defined from the back border by an acute ridge.

The crown of the last; premolar has the same constructioii as that in advance,
but is sliorter and wider. The heel is slightly wider and more excavated, but
the fore part of the basal ridge is not so prominent. The ridge defining the
inner side from the posterior border is slightly more advanced and prominent,
and the surfaces it separates are more concave.

The crowns of the true molars are nearly alike in form and size, though
the first is in a trifling degree more prominent and wider. They have the
same general constitution as those of shrews, of the hedgehog, the galeopi-
thecus, and the opossum. Eacli is composed of two divisions, of which the
posterior is the larger. The anterior division consists of a small, outer demi-
conoidal lobe, with aV-like summit joining by its arms a pair of inner and smaller
pyramidal lobes. The posterior division consists of an outer lol)e like that in
advance, but larger, and joining it by one of the arms of its V-like summit,
while the other arm joins a small pyramidal lobe at the inner corner of the
crown. The outer part of the base of the crown is embraced by a basal cin-
gulnm nearly half its depth.

The space occupied 1))^ the teeth, in the view that there were two incisors,
a canine, and six molars, is 74- lines. The last two premolars and the suc-
ceeding two molars occupy a space of 4.6 lines.

PALiEACODON.

Pal^acodon veeus.

Two small fossil specimens, discovered the previous, summer by Dr. Carter
at Lodge-Pole Trail, Wyoming, indicate an insectivorous animal, or, perhaps,
a marsupial allied to the opossum. One of the specimens consists of an
nppcr-jaw fragment containing a molar, which appears to be the penultimate
one of the series; the other is an isolated tooth, perhaps the last upper pre-
molar or first molar.

The jaw-fragment is the portion which forms the anterior abutment of the
zygoma. In advance of the tooth it retains are the remains of the alveoli of
two others, and behind it the remains of another.

Tlie molar of the jaw-fragment is represented in Fig. 46, Plate VI, magni-
fied four diameters. The crown bears some resemblance with that of the
molars of tiic opossum, ])ut is less narrowed internally, and is therefore more

123

(iu;iilr;iie or le.s.s triangular in tbrin. Tlie conslitiiiiou is similar, but, Uk^ oiilnr
lobes are proportionately better developed and the median ones are mticli
lediiced in size. A basal ridge nearly embraces the crown, ])ut is nearly
obsolete internally, and is best developed posteriorly, where it forms a wide
festoon.

The isolated tooth is a diminished representative of the one in the jaw-
fragment, and probably held the position of the third in advance of it. It
may, perhaps, represent a smaller species. The specimens indicate an animal
l)ut little more than half the size of the ©possum. How it is related with
Omomys the paucity of material prevents a positive determination. The size
of the teeth indicates a larger animal than Omomys Carteri.

In the American Journal of Science for 1871, Professor Marsh has
described a tooth, from Grizzly Buttes, which he likens to the premolars of
some insectivora, and refers it to a species with the name of Triacodon fallax.

He remarks that the species was probably about two-thirds of the size of
the opossum, which dimensions would be too great for the animal we have
named Palceacoclon verus.

The sizes of the teeth referred to the latter are as follows:

Lines.

Space occupied by tlie penultimate and antepenultimate molars 4

Breadth of penultimate molar 2

Width of penultimate molar 2^

Breadth of last premolar li

Width of last premolar 1 ^

WASHAKIUS.

Washakius insignis.

A jaw-fragment of a small animal recently sent to me by Dr. Carter is rep-
resented in Fig. 3, Plate XXVII, magnified three diameters. The specimen
was found in the Bridger beds by a Shoshone Indian and given to Dr. Carter.
It is quite different in appearance from any similar fossil from the same for-
mation submitted to my inspection, and appears to indicate a different genus
from those described in the preceding pages. I am uncertain as to its ordi-
nal affinities, but suspect it to have pertained to an insectivorous animal, per-
haps one of the many which have been indicated by Professor Marsh from tbssils
of the Bridger beds.

The jaw-fragment contains the last two molars, the triturating surfiices of

124

which, considerably worn, are represented in Fig. 4, Plate XXVIT, magnitied
eight diameters.

The portion of jaw is of moderate depth and stont in proportion. The
base is thick and rounded. The masseteric depression is well marked, and is
defined at its lower part in front by a strong ridge descending from the fore
part of the coronoid process and ending in a conspicnous angular tubercle.

The {eeth resemble most nearly tliose of Microsyops. They are inserted
with a pair of flings; but in the last molar the posterior fang is a connate pair
extended backward.

The crown of the antepenultimate molar is quadrate with rounded corners,
and is composed of four lobes. The postero-external lobe is largest, and is
crescentoid conical. The postero-internal lobe is smallest and conical, and is
joined at the summit by the back arm of the postero-external lobe. The
anterior pair of lobes are connate, and are joined about their middle by the
fore arm of the postero-external lobe. A deep angular valley occupies the
inner part of the crown between the anterior and postero-internal lobes, and
bounded externally by the postero-external lobe. A basal ridge incloses the
outer part of the crown, but is interrupted in the most prominent part of the
postero-external lobe.

The crown of the last molar, at its anterior two divisions, is composed on
the same plan as that of the molar in advance, but it is prolonged backward
so as to form an additional lobe.

The measurements of the specimen are as follows:

Lines.

Dei)tli of lower jaw below tlie last molar 2.1

Space occupied by the last two molars '. 2. 4

Breadth of second molar 1.2

Breadth of last molar . . ^ 1. 4

The genus I have named in commemoration of Washakie, chief of the
Shoshone Indians, with whom I had the pleasure of meeting during my visit
to Fort Bridger. He has always been distinguished for his high characler,
and for his friendliness to the white race.

ELOTHERIUM.

In tlie American Journal of Science of 1871 Professor Marsli has described
a molar tooth, from Hejiry's Fork of Green River, which he attributes to a
suilline pacliyderm with the name of Elotherium lentus. The specimen, he

- - 125

observes, indicates a species about half tlic size of E. Morfoni, tlie reiuaius
of wiiicli are found in the Miocene Tertiary deposit of (he Mauvaises Terres
of White River, Dakota.

Among the colh^ctions of fossils from the Bridger beds I have seen no
remains which could be ascertained to belong to this genus. Figs. 28 and
29, Plate VII, represent two views of an incisor tooth which looks as if it
might pertain to E. Morto)ii. The specimen was found by Mr. Pierce, ol"
Denver, twenty miles southeast of Cheyenne City, Wyoming.

REPTILIA.

The Bridger Tertiary formation, in comparison with the earlier Tertiaries
of White Eiver, Dakota, and of the Niobrara River, Nebraska, is remarkable
for the variety as well as the number of its reptilian remains. Amid the
multitude of fossils which Rave been collected in the latter localities nearly
all belong to mammals; and though the remains of turtles are abundant, they
appear all to be referable at most to a single species for each locality. No
fragment of a crocodilian, lacertian, or serpent has yet been discovered either
in the Mauvaises Terres of White River, Dakota, nor in the sands of the
Niobrara River, Nebraska. From the Bridger beds there have been col-
lected many remains of different species of crocodiles, turtles, lacertians, and
serpents.

Order Crocodilia.

Body lizard-like in form, with four short limbs and feet, and a long,
powerful tail. With long jaws, provided with a single row of teeth inserted
in distinct sockets. Skin protected by bony plates.

CROCODILUS.

The Bridger Tertiary formation contains numerous remains of crocodiles.
Many collected by Professor Hayden's party in 1870, and olhcrs obtained by
Drs. Corson and Carter during the same and the succeeding year, have been
submitted to the inspection of the writer. The specimens were found in
various localities in the vicinity of Fort Bridger, as Little Sandy River, Big
Sandy River, Green River, Black's Fork of the same, Church Buttes, Grizzly
Buttes, &c. The specimens examined indicate several species, though from
their generally detached and imperfect condition we have not been able to
collocate them so as distinctly and clearly to establish the species. Some of

126

the specimens we have referred to two named species. Professor Marsh
subsequently named five species from remains obtained in the same locali-
ties during his exploration of 1870. Professor Cope has more recently named
four additional species. It is probable that when the fossils are more care-
fully studied, the number of sjjecies to which they have been referred will
be reduced.

Crocodilus aptus.

This species was originally named in 1869 from a fossil preserved in the
Greological Cabinet of tlie General Land-Office in Washington. The speci-
men was obtained by Colonel John H. Knight, United States Army, near
South Bitter Creek, Wyoming. Though consisting of a detached vertebra, it
especially attracted my attention from having previously seen no remains of
crocodiles in the large collections of fossils from the Tertiary formations of the
west.

The vertebra represented in Fig. 2, Plate VIII, belongs to the cervical
series, and resembles, botli in size and form, the sixth or seventh of the Mis-
sissippi alligator. The bone appears to have been of mature age, and seems
thoroughly petrified. It has lost the greater part of its neural arch and
dependent processes, but is otherwise well preserved. From portions of
adherent matrix, it has been imbedded in arsofl rock similar to that adherent
to some of the bones from other localities above mentioned.

The body of the bone in its axis is 16 lines long; its height and breadth
in front are 14 lines. The hypopophysis, directed obliquely downward and
forward, as in the alligator, is about 5 lines long. Back of the process the
Ijody is less prominently carinated than in the latter animal.

Crocodilus Elltotti.

The species thus named was originally designated from a specimen
obtained, during Professor Hay den's exploration of 1870, at the junction
of the Big Sandy and Green Rivers. It consists of an upper-jaw fragment
containing two teeth and portions of two others, and is represented in Fig. 4,
Plate VIII. It appears to be the anterior portion of the left maxillary, con-
taining the fourth and fifth maxillary teeth and the fangs of the two succeed-
ing ones. The shape of the jaw-fragment is nearly like that of the corre-
sponding portion of the upper jaw in the mugger {Crocodilus paluslris) of
India, but is more rugose on its exterior surface, and the palatine surface is

127

more vaulted. The teetli retained in the specimen have tlieir crowns only
partially protruded. Tiiey are proportionately more robust, or shorter and
less pointed, than in the mugger. Strong ridges define the inner from the
outer surfaces of the crown, which exhibits no indication of fluting, but the
enamel is finely and closely wrinkled longitudinally.

The space occupied by the teeth, from the fourth to the seventh inclusive,
is 35 lines. The entire length of the fifth or largest maxillary tooth is esti-
mated at about 2^ inches. The protruded portion measures externally ^ of
an inch in length, and its diameter at base fore and aft is 7J lines, and trans-
versely GJ lines.

Fig. 6, Plate VIII, represents a large portion of the upper part of a skull,
which has been attributed, but with no certainty, to the same species as the
foregoing. The specimen, in a number of scattered fragments without teeth,
was discovered, by Henry W. Elliott, on Little Sandy River, during Pro-
fessor Hayden's exploraticni of 1870.

The fossil indicates a form of skull very difierent from that of our alligator,
and is that of a true crocodile. It approached in form more tiiat of the mugger of
India or of the Nile crocodile than that of the American crocodile, (C ameri-
canus.)

The cranium above is remarkably flat ; from its lateral borders defined by
the squamosals and post-frontals, and from the occipital border to the face in
advance of the orbits, it forms a nearly uniform plane with no depression of
the forehead nor eversion of the orbital margins. This uniform flatness is
also extended along the middle of the face to the muzzle. This and the
alveolar borders of the face are about as convex as in the mugger.

The sides of the muzzle are deeply notched at the conjunction of the pre-
maxillaries and maxillaries, and the bottom of the notch exhibits a conspicu-
ous recess for the accommodation of the large canine-like tooth of the man-
dible. A second and less conspicuous notch, as usual in the true crocodiles,
occupies a position about the middle of the maxillaries.

The lateral boi'ders of the cranium are less angular or more rounded
approaching the orbits than in the mugger and the American crocodile.
The superior temporal orifices are subrotund and nearly as wide transversely
as fore and aft. The intervening parietal surface is broad and deeply
l)itted. The temporal surfaces of the parietal form a pair of deeply concave
recesses.

128

The anterior orl^ital Ijorder, as constituted by tlie prefrontals and lachry-
mals, is depressed or slopes inwardly toward the orbits.

The nasal process of the frontal is niucli prolonged, extending 2 inches
in advance of the position of the ant-orbital margins. The prefrontals are
proportionately long and narrow compared with those in the mugger. Their
length is about 4 inches ; tlieir breadth, where widest, is 14 lines.

The nasals are broad and flat at the back part. They are proportionately
of greater breadth than in the mugger. Their estimated length is 9i inches;
their breadth together in advance of the lachrymals is about 2J inches.

The fore part of the face, or the muzzle, has the same form as in the mugger
and other true crocodiles, but is proportionately less thick than in the one
specifically mentioned. The nasal orifice holds a more advanced position
than usual, so that the alveolar border in front is barely more than half the
extent it is in the mugger, nor is it perforated as in the latter and other true
crocodiles. The upper surface of the skull is everywhere exceedingly rugose,
with reticular ridges inclosing deep pits, and in some positions is deeply
scored by vascular gi'ooves.

Four teeth occupied the sides of the premaxillaries, forming an unbroken
row. The intermediate pair are the larger and of nearly equal size ; the
others are also nearly of equal size. The tirst tooth did not occupy the fore
part of the premaxillary as usual, in the true crocodiles, but is over an inch
from the position of the symphysis, close to the second tooth. A large recess
occupies the fore part of the palatine surface of the premaxillary, for the
accommodation of the first mandibular tooth, as usual in the crocodiles, but it
is closed or does not communicate by a perforation with the upper surface of
the premaxillary border. The recess holds a position internal to the first pre-
maxillary tooth. Smaller conical recesses occupy the intervals internally of
the succeeding three teeth.

The maxillary appears to have accommodated fourteen or fifteen teeth, of
which the fifth one was the largest, as in other crocodiles. The fourth, in
comparison with the fifth one, .was proportionately larger than in the mugger,
and the sixth was not much less in size.

The depth of the socket of the fifth maxillary tooth is full 2 inches ; its
fore and aft diameter about f inch. The depth of the fourth socket is 20
lines : its diameter 8 lines.

The premaxillary teeth, in comparison w ith those of the mugger, appear to

129

have l)cen proportionately about as large. The anterior scries of maxillary
teeth were rather larger, and the posterior series smaller.

Detached portions of both quadrates accompany the other portions of the
skull. They are somewhat peculiar in several anatomical points. The an-
terior surface is unequally divided by a conspicuous ridge, descending to
within an inch of the articular surface for the mandil:)le. The grooved or
trochlear condition of the latter surface is much more decided than in the
mugger or the American crocodile.

Measurements taken from the specimen above described are as follows :

luclics.

Length from occipital border to end of muzzle • 20

Breadth of cranium at occipital border between prominent angles of .squamosals. 7

Breadth of cranium at postorbital angles 51

Breadth of cranium between temporal orifices . . 1

Breadth of forehead between orbits I.1

Breadth of temi)oral orifices 1.^

Fore and aft diameter of the same 1^

Leugth of parietal 2;^

Length of frontal 5.1

Bi'eadth of frontal where it joins the post-frontals 2,^^

Fore and aft diameter of the orbits 2-^

Length of face in advance of the orbits i:j.i

Breadth of face outside the fifth maxillary teeth (ja

Breadth of muzzle as formed by premaxillaries 5

Breadth of muzzle at notch back of the latter 4

Leugth of i>remaxillaries G

Breadth of nasal orifice , 2A

Fore and aft diameter of the same 2.^

Thickness of premaxillaries in advance of the same ^

Estimated length of entire alveolar border 14^

Space occupied by the anterior five maxillary teeth 3f

Space occupied by the posterior five maxillary teeth 3

Breadth of articular surface of quadrate for the mandible 2^

A detached basi-occipital, obtained near Little Sandy River, may, perhaps,
belong to the same species as the preceding. The occipital condyle has
nearly as great a vertical as a transverse diameter, the former measuring 15
lines, the latter 17 lines.

The last summer Dr. Joseph K. Corson sent, as a gift to the museum of the
Academy of Natural Sciences of Philadelphia, a specimen consisting nearly
of the whole of the lower jaw of a large crocodile. He discovered the fossil
imbedded in a green sandstone in the vicinity of Fort Bridger. In removing

it from its matrix it was much broken, and most of the teeth were destroyed.
17 G

loO

The left ramus in a restored condition is represented in Fig. 8, Plate VIII,
one-half the natural size.

The lower jaw belonged to a larger animal than the cranial specimen from
Little Sandy River, and probably pertained to a different species. The form
of the jaw is nuich like that of the mugger, but is of more robust proportionss
The rami, in their dentary portions, are much thicker in proportion to their
depth, and the symphysis is of greater extent, in this respect presenting a
greater resemblance to the condition iu the American crocodile.

The dentary portions of the rami the greater part of their length are as
thick and thicker than the depth. Half way between the symphysis and the
median enlargement of the dentary portion of the ramus the thickness is over
2 inches, while the depth is ^ of an inch less. In the position of the enlarge-
ment just mentioned, the thickness is 2 inches and 2 lines, while the depth
is only 2 lines moi'c. The symphysis has measured about 44' inches fore and
aft, and liut slightly more than this transversely opposite the position of the
large canine-like teeth.

The splenial bone, as if to give greater strength to tlie ponderous jaw,
extends close up to the symphysis. The outer portion of the jaw in the posi-
tion occupied by the teeth, is more rounded than in the mugger. The back
portion of the jaw in form and constitution appears to agree with that in the
mugger. The outer surfi\ce of the jaw, strongly ll)veated back of the hu-ge
oval foramen, presents the usual vascular grooved and perforated appearance
in advance.

AI)out eighteen teetli occupied each ramus of the jaw, but all are broken
from the specimen except one. Some of the broken and detached teeth
accompany the jaw. They appear to have been comparatively robust, short,
and blunt, conical in form, and but feebly curved. The enameled crown is
rugose and longitudinally grooved, but not properly fluted; the narrow grooves
separating wider convex and rugose longitudinal ridges. They sufficiently
differ from those in the jaw-specimen referred to Crocodilus Eltlotti to per-
tain to a different species.

The end of the symphysis of the jaw ov of the chin is l)rokcn away, so that
nothing can be ascertained in regard fo the first pair of teeth of the two
i-ami. A lai'ge tooth, canine-like in its relative position and size, as usual in
the crocodiles, was nund^er t()nr in the series. Tlie sof^kct, occupied by
green-sand matrix, is about 10 lines in diameter. The expansion of the sym-

131

[ihysLs in the position of this socket indicates its caniiic-likc leelh to have
been accoaimodatcd when at rest iu a recess of the upper jaw at the junction
of the premaxillarics and inaxiikiries.

Succeeding the canine tooth alveolus, there are the remains and sockets oi"
five comparatively small teeth. Then followed several ol' the largest teeth
accommodated by the second expansion of the jaw. The socket for the
eleventh tooth is about the size of that of the canine tooth. In the left ramus
it retains the tooth, the apex of which alone had protruded. After tliis tooth
there followed a series of five others which successively decreased in size.

Measurements of the lower jaw are as follows :

Incbes. Lines.

LeDgth of rami of lower jaw 20 G

Width of lower jaw outside the glcuoid articn]ation.s 12 0

Width of lower jaw a short distaace in front of the glenoid articulatious.. 13 0

Greatest width of symphysis 4 o

Width of jaw at second enlargement, below the eleventh tooth (J 0

Depth of jaw at oval foramen 3 10

Depth of last tooth 2 8

Depth of eleventh tooth 2 4

Thickness below the eleventh tooth , 2 2

Depth of ramus near symphysis 1 !)

Thickness of ramus near symphysis 2 2

Extent of symphysis fore and aft 4. 3

Breadth of glenoid articulation 2 7

Length of hook-like process back of glenoid articulation 2 5

Space occupied by the teeth 11 0

Length of oval foramen 2 8

W^idth of oval foramen .' 0 11

Fig. 1, Plate VIII, represents the body apparently of a first Inml^ar verte-
bra; and Fig. 5 of the same plate, the proximal extremity of a left femur,
large enough to belong to the same animal as the cranium above described.

The two specimens were found together by Professor Hayden's party near
Little Sandy Eiver. They present no decided peculiarity distinguishing them
from the corresponding part in the living crocodiles. The shaft of the femur
contains a medullary cavity larger than usual in the latter, and in the specimen
it is filled with chalcedony.

The measurements of the specimens are as follows:

Line.s.

Length of body of first lumbar vertebra beneath 20

Depth of body anteriorly 18

Width of body anteriorly ' 18

Width of head of the femur 20

Diameter of shaft below the inner process 12^

132

Fig. 3, Plate VIII, represents a specimen of a first caudal vertebra of a
smaller species of crocodile than those indicated by the preceding specimens.
It was obtained by Professor Hayden's party near Little Sandy River. The
length of the body with its double ball is 21J lines. Several other vertebra?
from Black's Fork of Green River, and from near Church Buttes, Wyoming,
from their size and conformation, would appear to belong to the same species.

Order Chelonia

No other Tertiary deposit in North America has yielded such an abun-
dance of remains of different species and genera of turtles as the Bridger beds.
The fossils represent a large proportion of fresh-water and paludal forms ; the
others pertain to land tortoises. Fragments of turtle-shells are the most fre-
quent of the vertebrate fossils met with, strewed on the bare tops and sides of
the buttes or among the debris at their base. Entire shells are comparatively
rare, and if they have been complete as fossils, they soon undergo disintegra-
tion after exposure on the Inittes. Most of them have been much crushed,
while embedded, under pressure of the superincumbent strata, and now when
exposed from the softening of the matrix they readily fall to pieces.

The greater quantity of the turtle remains are referable to a species of fresh-
water terrapin of the genus Emys, the shells of which present sufficient variety
as to have at first misled me in referring them to several different species.
The next most abundant remains are those of one or two species of soft-shelled
turtles of the genus Triouyx, and after these the remains of a large land-tor-
toise. Besides the species and genera described in the succeeding pages.
Professor Cope has recently indicated a number of others from the same for-
mation.

TESTUDO.
Testudo Corsoni.

Among the many remains of turtles from the Bridger Tertiary beds are
those a^jparently of a large land-tortoise. Small and for the most part un-
characteristic fragments of the shell were obtained by Dr. Carter in 1869
and during Professor Hayden's exploration of 1870, but it was not until I
received the specimen represented in Fig. 7, Plate XV, that I recognized the
character of the species to which they pertained.

The last-mentioned specimen was discovered by Dr. Corson at Grizzly

133

BiiJtes. It consists of the anterior extremity oftlie under shield or ])Iastron,
consisting of the fore part of the episternals and the end of the entosternal.
The specimen might l)e supposed to belong to an Emys, but its resemblance
in form with the corresponding part in living species of Testudo leads me to
place it with this genus. The episternals project together rather abruptly
into a long, thick, and broad spade-like process, nearly straight at the front
border, but slightly notched at the middle. The projection behind is defined
by the outer extremities of deep grooves defining the gular and humeral scute
impressions. Its lower surface is strongly convex ; the upper surface slopes
forward to the acute border of the process.

Back of the gular surface above, the plastron is deeply concave, but is not
excavated beneath the former as in the gopher, {Testudo Carolina.)

The end of the entosternal plate is impressed l>y the contiguous ends of the
gular scutes. The episternal process is about 2 inches long ; its breadth at
base is 5^ inches. The extremity of the process is 3| inches in width. The
thickest part of the episterna measures IJ inch.

The species I have named in honor of its discoverer. Dr. Joseph K. Corson,
United States Army, who to a love of his profession adds a special interest
in the promotion of the natural sciences.

During my recent trip to Fort Bridger I was so fortunate as to obtain a
number of additional specimens referable to Testudo Corsoni. Some of them
had been previously collected I)y Drs. Corson and Carter, and others were
found during our explorations of the battes near Fort Bridger, and those of
Dry Creek ten miles from the former.

One of the best preserved specimens consists of a nearly complete ventral
shield or plastron, represented in Fig. 2, Plate XXX. This was discovered
by Dr. Corson at Grizzly Buttes, and presented by him to the Academy. In
the complete condition it has measured upward of 2 feet in length, and is
estimated to have been about IG inches in breadth to its sutural conjunction
with the upper shell.

In its form and propoi'tions it resembles that of the living Testudo radJala
of Madagascar more than it does that of the great Galapagos tortoise.
. The lobes of the plastron are of nearly equal length and breadth. The
prolonged extremity or spade-like process of the anterior lobe is lost in the
specimen. The posterior lobe terminates in a deep, wide, angular notch
included by two angular processes.

The fore part of the anterior lobe is slightly bent ujiward and nearly straight

134

transversely. The plastron Iroui the position of the pectoral scute impres-
sion l)ackwar(l becomes gradually and deeply concave. The deeper part of
.the concavity is defined on the posterior lobe of the plastron by a narrow flat
ledge laterally, which widens behind on the angular processes terminating the
plastron. The sternal bridges are moderately convex, and are wide fore and
aft.

The anatomical structure of the osseous plastron and the relative position
and number of its scutes are the same as in modern species of Testudo.

The entosternal bone is subpyriform and wider than long. Its fore extrem-
ity reaches just in advance of the ends of the gular scute impressions, and its
back border reaches the groove defining the humeral and pectoral scute
impressions.

All the grooves defining the scute impressions are well marked, being deep
and wide. The proportions of the scute impressions are nearly the same as
in recent testudines.

The pectoral scute impression is longer at both extremities than interme-
diately. The groove defining it in front, commencing externally just in
advance of the bottom of the axilla, curves backward and inward, and then
turns forward and inward to the position of the back suture of the entosternal
plate.

The measurements of the specimen are as follows :

Inches.

Estimated length iu median line to bottom of poststerual uotcli 24

Estimated leugtli on each side to ends of poststerual processes 20^

Estimated width 2o"

Estimated length of anterior lobe of plastron in median line 8

Length of posterior lobe of plastron iu median line 5

Length of posterior lobe of plastron laterally 7

Width of anterior lobe at bottom of axilla; 12

Width of posterior lobe at bottom of inguinal fossa; 13

Width at bottom of anterior prolongation of i^lastrou 5

Width at ends of poststerual angular processes 7i

Depth of ijoststernal notch 2J

Width fore and aft of sternal bridge 9^

Length of entosternal plate 4J

Width of entosternal plate 5^

Length of hyosternal plate in median line (i^

Length of hyposternal plate iu median line 5^

Length of xiphisternal plate in median line 4^

Length of pectoral scute impressions iu median line , 1^

Length of i)ectoral scute impressions where narrowest 1

Length of abdominal scute impressions iu median line 9

Length of femoral scute impressions in median line 3j

135

Inebes.

Length of caudal scuto impressions in median line 2^

Tliickuess of plastron at base of anterior prolongation liJ

Thickness of anterior lobe laterally near bottom of axilla 1

Thickness of posterior lobe near bottom of inguinal fossa 1^

Thickness of plastron near the center iJ

During a day's excursion to Dry Creek Buttes, ten miles from Fort Bridger,
Mrs. Anna Carter, the wife of Dr. Carter, who accompanied us, discovered a
large turtle jiartially imbedded in a green sandstone on the top of a butte.
The upper shield had been destroyed by recent exposure, but the nearly com-
plete plastron was obtained by removing the cast of the shell above it. The
sutural connections of the bones are somewhat obscured by the firm adhei'ence
of particles of sand. It retains the anterior spade-like process nearly entire,
and this is represented in Fig. 4, Plate XXX.

The specimen presents some differences from the former, which, however,
I have not regarded as specific, though they may be so. The spade-like pro-
longation of the plastron is more abrupt and considerably longer than in the
fragment upon which the species was originally founded. The fore part of
the anterior lobe of the plastron approaching the lateral border along the
groove defining the gular and humeral scute impressions is much more convex
than in either of the preceding specimens. From the position of the entoster-
num backward, the plastron becomes concave, as in the former specimen, but
the concavity is comparatively shallow. The poststernal notch is also of less
depth than in the previous specimen, but otherwise the plastron is sufficiently
like the latter to pertain to the same species.

The measurements of the specimen are as follows :

Inches.

Length of plastron in median line ^5

Length of plastron on each side 2Gi

Width of plastron at middle, estimated at about 20

Length of anterior lobe 9

Length of posterior lobe at middle 6

Length of posterior lobe to ends of angular processes 8i

Width of anterior lobe at base 12

Width of posterior lobe at base HJ

Length of episternal prolongation 2i

Width of episternal prolongation at base ^i

Width of episternal prolongation near end ^'i

Breadth of sternal bridges fore and aft ^

Breadth at ends of poststernal angular processes 'i

Depth of poststernal notch 1 4

Length of entosternal boue • - • ■ 4?

Bi'eadth of entosternal bou(> ^i

106

In some low Ijuttes on the road to Carter Station, about three miles from
Fort Bridger, Dr. Carter found a large turtle, which I viewed as jjertainiiig
to Tcstudo Corsoni. As it lay partially exposed it measured about 2 feet 4
inches in length, and approximated 2 feet in breadth. It was so much
broken that in the attempt to remove it, it fell into a multitude of fragments.

In Dry Creek Canon we discovered another turtle, which I viewed as T.
Corsoni. The shell was in great part decomposed, but the rock which had
occupied the interior still preserved its form. From this cast we estimated
the shell to measure 28 inches long, 20 inches broad, and 14 inches high.

Another specimen of a large turtle, discovered by Dr. Corson on the buttes
of Dry Creek, consisted of fragments of a plastron with a few marginal plates
of the carapace. The plastron, of which we have been enabled to restore
the greater part of the anterior lobe, presents peculiarity enough to pertain
to a distinct species from T. Corsoni. It was about the size and proportions
of the plastron attributed to the latter, but the episternals are neither so
aljruptly nor so much prolonged as in the former specimens, and the front
part, as represented in Fig. 3, Plate XXX, is decidedly notched. The under
surface of the extremity of the anterior lobe is flatter.

The bony construction of the plastron, so far as preservecf, is the same as
in the former specimens, and the entosternal is nearly of the same size and
hape.

The scute impressions are also the same as in the former specimens, except
that the pectoral scute impressions arc nearly twice as long.

Fragments from the back lobe of the plastron retaining the bottom of the
poststernal notch indicate this to be more acute than in the former speci-
mens.

The measurements of the specimen are as follows :

lutbes.

Length of anterior lobe of the plastrou 8

Breadth at base ]0J

Length of episternal prolongation ] ;i

Breadth of episternal prolongation at base 5i

Breadth of episternal prolongation near the extremity 4^

Length of entosternal plate 4J

Breadth of entosternal plate 5J

Length of gular scute imi^ressions 3^

Length of humeral scute impressions 4J

Length of pectoral scute impressions " 3

Length of pectoral scute impressions where least , . . li

•I 07

Portions of llic sliell ol' anolhcr specimen, apparently referable to Tesludo
Corso)//, were discovered by Dr. Corson on Dry Creek Buttes. Several of
the fragments so far recompose one side of the back lobe of the plastron as
to determine its identity with that of T. Corsoni. It is especially interesting
irom its being accompanied b}^ a number of fragments of the upper shell,
wliich being reunited compose the middle portion, as represented in Fig. 1,
Plate XXX. Tills specimen tends to confirm what I have latterly suspected,
namely, tliat the specimens formerly described anil represented in Plate XI,
under the name of Emys Carteri, really belong to Tesludo Corsoni. The
specimens originally referred to the former, though much naore complete
than the one upon which the latter was founded, completely misled me. The
spade-like process of the plastron was not simply broken off, but, while
imbedded in its matrix, was crushed or squeezed off in such a manner as to
leave but little trace of its true character. The accompanying portion of the
carapace exhibited the costal plates with strong costal capitula as in living
species of Emys. This emydoid character with others are probably suffi-
cient indications that the specimens would properly be referable to a genus
distinct from either Testudo or Emys, and is probably the same as that
recently proposed by Professor Cope, under the name of Hadrianus.

The specimens originally referred to Emijs Carteri, 1)ut now viewed as
pertaining to Testudo Corsoni, were discovered by Dr. Carter in the buttes
near Fort Bridger. They consist of the greater part of a mutilated plastron
with the ends broken off, and the anterior median portion of the carapace.

The plastron represented in Fig. 1, Plate XI, resembles, in its size, form,
and proportions, the nearly complete specimen above described and repre-
sented in Fig. 2, Plate XXX. It is not so concave posteriorly, but other-
wise presents nothing peculiar.

The portion of the carapace represented in Fig. 2, Plate XI, consists of
the nuchal and anterior three vertebral plates with fragments of the contig-
uous costal plates.

The anterior border of the fragment is slightly emarginate. The vertebral
region is flat, and slopes forward from the anterior half of the first vertebral
plate. The nuchal plate is nearly as long as wide, and its antero-lateral
borders are moderately convergent.

The first vertebral i)late is clavate in outline with the broad end behind.
The anterior narrow end dips into an emargination of the nuchal plate. Its
widest part is less than a fourili of its length in advance of its posterior
■ 18 G

138

border. The second vertebral plate presents the usual hexagonal coffin-like
outlhie, l)iit in a reversed' position, its broadest part being about one-fifth of
ils length in advance of its liack border. Tlie third vertebral plate is oblong
quadrate, with the fore and lateral borders convex, and the back one nearly
straight.

The sutures defining the first costal plate depart from the anterior narrow
end and the posterior widest part of the first vertebral plate. The scute
impressions of the carapace are well defined Ijy deep grooves.

The nuchal scute impression is flat, and widens anteriorly. Tiie first mar-
ginal scute impression is wider than long.

The first vertebral scute area is longer than broad, and is purse-like in
outline.

The second vertebral scute area is also longer than broad, and is quadrate,
with the lateral borders nearly parallel.

The fragment of the carapace from its front border to the back l>order of
the third vertebral plate measures 134 inches.

Other measurements of the carapace are as follows :

Lines.

Length of nuchal plate 50

Breadth of nuchal plate iu front 44

Breadth of uuchal plate where widest GO

Length of first vertebral plate 48

Breadth of first vertebral plate in front 9

Breadth of first vertebral plate where widest '. 30

Breadth of first vertebral j)late at back border 14

Length of second vertebral plate 27

Breadth of second vertebral plate where widest 20

Breadth of second vertebral plate at back border 10

Length of third vertebral plate 29

Breadth of third vertebral plate at middle 22

Breadth of third vertebral plate at back border .■ 17

Length of nuchal scnte impression 21

Breadth of nuchal scute impression iu front 11

Breadth of nuchal scute impression behind 0

Length of first marginal scute impression 20

Breadth of first marginal scute impression behind 38

Length of first vertebral scute impression 07

Breadth of first vertebral scute impression in front 32

Breadth of first vertebral scute impression near middle r>2

Breadth of first vertebral scute impression at back border 43

Length of second vertebral scute impression 58

Breadth of second vertebral scute impression at middle 48

The accompanying plastron measured, in its complete condition, upward

of 2 feet in length and about 1 i feet in breadth.

139

Other luoasunMnoiiis oftlio specimen are as I'ollovvs :

Linos.

Widtli of iinterior lob(^ of pliistrou at base lO.S

Width of posterior lobe of plastron at base ll'l)

Breadth of sternal bridyos fore and aft 114

Length of entosterual plate 50

Breadth of entosternal plate (i.'!

Length of hyosteruals iu median line of plastron GO

Length of hyposteruals in median line of plastron Gl

Length of humeral scute impressions 48

Length of pectoral scute impressions 2G

Length of abdominal scute impressions 82

Length of femoral scute impressions 47

The portion of a carapace represented in Fig. 1, Plate XXX, and previ-
ously referred to as tending to confirm tlie impression tiiat Emys Carterl was
the same as Testudo Corsoid, retains most of the vertebral plates with contig-
uous fragments of tlie costal plates.

The anterior three vertebral plates, corresponding with those which are
retained in the specimen originally referred to Emys Carteri, have the same
form, but are wider. The succeeding two plates have the same form as the
second vertebral plate in a reversed position. The sixth vertebral plate is
too much broken to ascertain its exact form, but it would appear to be nearly
the same as those in advance. The seventh plate is hexagonal, with the
breadth more than twice the length ; and the eighth plate has the same form,
but is not so broad.

The length of the fragment of the carapace from the anterior broken end
of the first vertebral plate to the back border of the eighth plate is 10 inches.

Other meastirements are as follows :

Lines.

Length of first vertebral plate, estimated 40

Breadth of first vertebral plate in front 14

Breadth of first vertebral plate where widest ?>1

Breadth of first vertebral plate at back border 17

Length of second vertebral plate 27

Breadth of second vertebral plate where widest 28

Breadth of second vertebral plate at back border 18

Length of third vertebral plate 28

Breadth of third vertebral plate at middle -*3

Length of fourth vertebral plate 20

]3readth of fourth vertebral plate in front 29

Length of fifth vertebral plate - 24

Breadth of fifth vertebral plate in front 27

Length of sixth vertebral plate 20

140

Linos.

Length of seventh vertebral plate 13

Breadth of seventh vertebral plate. 28

Length of eighth vertebral plate 13

Breadth of eighth vertebral plate 24

The costal capitulti of Testudo Corsoni appear in the specimens as robust
conical eminences, with a Ijroad, expanding base, and are proportionately
better developed than in living species of Testudo, and even many of the
species of Emys.

Figs. 2, 3, Plate XXIX, represent the upper extremity of a humerus, and Fig.
4 the lower extremity of a femur, which were found in association with the
fragment of a carapace last described, and may reasonably be supposed to per-
tain to the same animal. Both fragments resemble the corresponding parts
of a modern Testudo.

The head of the humerus has an inner trochlear extension, as in recent
species of Testudo. Independent of this process, the transverse diameter of
the head is nearly as great as the fore and aft diameter. In the specimen it
presents a discoidal, flat surface, but this is evidently accidental.

The measurements of the specimens are as follows :

Lines.

Breadth of humerus between tuberosities 29

Breadth between outer tuberosity and inner extension of the head 32

Breadth of the head with its inner trochlea _ 20

Fore and aft diameter of the head 17

Breadth of the distal end of the femur 2-1

EMYS.
Emys wyomingensis.

Of the many remains of turtles from the Bridgcr Tertiary deposits I have
had an opportunity of examining, most of them appeaf to me to belong to a
species of Emys, which presents so much variation in anatomical details that
the first specimens brought to my notice were viewed as pertaining to no less
than four distinct species. These were named Emys imjomingensis, E. Steven-
sonianus, E. Jeanesi, and E. Haydeni. A subsequent examination of ad-
ditional specimens, collected by Dr. J .Van A. Carter and Dr. Joseph K. Cor-
son, United States Army, and presented by them to the Academy of Natural
Sciences of Philadelphia, has led me to regard all those indicated under the
above names as really pertaining to a single species. I admit that I may be
wrong in this determination, but if such is the case, it would appear that
almost every specimen presents characters to distinguish a species.

141

Regarding all the specimens under consideration as pertaining to a single
species, this would retain the original name of Emys wyomingensis.

The composition of the shell so far as relates to the attachment of the
carapace and plastron, the number of bones or plates and the number and
relation of the corneous scutes, is the same as in living species of the genus
Emys.

In the mature condition, the shell of Emys ivyomingensis is upward of a
foot in length, with about tliree-fourths the same measurement iu breadth.

To what degree the shell varies in form, that is to say in relation of length
and breadth with the height, and in outline, cannot be determined from the
material at command, on account of the imperfection of the specimens, or
their distortion from the original condition, due to pressure or to a crushing
force applied to them while imbedded in the strata from which they were ob-
tained.

The elements of composition, especially the vertebral plates and scutes,
differ more or less in different specimens, both in form and in the relation of
length to the breadth. While the length of the vertebral scutes in general
exceeds the breadth, especially in the case of those intermediate, in some
specimens even to the extent of being a third greater, it nevertheless varies
so much that in some instances it barely exceeds the breadth. The verte-
bral plates vary in the same manner in different specimens, nor does this
variation always accord with that of the same character in the vertebral scutes,
that is to say the elongation of the scutes is not always accom|)anied in a
proportionate degree with elongation of the plates.

1. Emys tvyomingensis was originally described from an isolated episternal
bone, sent to the writer by Dr. Carter. It was the first of the remains of
turtles from the Bridger Tertiary deposits, which could be referred to the
genus. It is represented in Fig. 5, Plate IX, and exhibits the usual form of
that in living species, but further presents the appearance of being impressed
by a narrow intergular scute. The presence of the latter I suspect to be ac-
cidental or anomalous, though it may be normal, and may really indicate that
the fossil belongs to a species distinct from those which I am now disposed
to view as the same. The front of the specimen is truncated and slightly
notched at the outer part.

2, 3. Emys Stevensonianus is the name originally given to a supposed
species founded on the specimens represented in Figs. 2, 4, Plate IX. These

142

were collected l)y Dr. Carter in the vicinity ot" Fort Bridger, and t<ent to the
Smithsonian Iiistitntion, whence I obtained them for examination. The
specimens consist of portion of a carapace, Fig, 2, and portions of two plas-
trons, Figs. 3, 4. Slight difference in the corresponding portion of the latter
specimens with that attributed to E. icyomingensis, but especially the absence
of any evidence of an intergular scute, led to their being referred to another
species.

The sternal specimen, represented in Fig. 3, accompanied the portion of a
carapace, represented in Fig. 2, and from its appearance was assumed to have
belonged to the same individual.

In the sternal specimen just indicated, the entosternal plate is lozenge-shaped
in outline, l)ut constricted at the middle of its posterior part. Its length is
equal to the breadth, but the evidence from the isolated episternal, first re-
ferred to E. wi/ominge7isls, is that its entosternal was wider than long.

The divisions of the plastron and its impress by scutes, as seen in the more
perfect specimen, appear to agree pretty closely with the arrangement ob-
served in ordinary living emydes.

The second sternal specimen, represented in Fig. 4, was supposed to ])er-
tain to the same species as the former one, though exhibiting differences
whicli rather approached it nearer to that first referred to E. loyomingensis,
except that it exhibited no trace of the existence of an intergular scute. The
entosternal bone is wider than long, and without conspicuous constriction at
its posterior part. The anterior truncated border of the episternuin is con-
spicuously notched at its outer part.

In all the sternal specimens indicated, the gular and humeral scutes have
doubled over the edge and extended upon the upper surface in the same man-
ner as in living emydes.

In the carapaceal specimen, Fig. 2, the vertebral plates, consisting of the
series from the first to the eighth, inclusive, successively decrease in length
except that the third is a little longer than the second, and the llnirtli and
ilflh arc nearly ecpud. To the fourth inclusive, the length much exceeds the
breadth, but they successively diminish in this proportion. The fifth is but
slightly longer than wide, and the remaining plates are much wider than long.
The second and fifth are of the same width, and in this respect exceed the
finst and intermediate ones, which are likewise of neai'ly uniform breadth.
The sixth plate is the widest of the scries; the others successively diminish.

143

They exhibit Ihe usual ('onus, Ihc first l)ciiig oblong with the borders convex
outwardly, the others to tiie lifth being wide coffin-shaped, and the remaining
ones are more regularly hexagonal.

The second and third vertebral scute-spaces are quadrate with the lateral
defining-grooves strongly double sigmoid. The second space is Ijroader than
long, but the third is the reverse.

4. It was the nearly complete shell, represented in Plate X, which was
attributed to a different species from the former specimens, under the name
of Emys Jeanesi. This fine fossil was obtained near Fort Bridger, Wyoming,
during Professor Hayden's exploration of 1870. It is considerably distorted
from pressure, the right side being crushed inwardly so as to be nearly ver-
tical. The shell, completely petrified like all its associate fossils, is filled
with a greenish-gray sandstone. Its prominence or convexity in the original
condition was perhaps not greater than in some of the ordinary living emydes,
but it is apparently more prominent, from the lateral pressure to which the
shell has been subjected.

The carapace is oval in outline with the l>orders moderately deflected,
acute, and without conspicuous indentations, except that it is slightly notched
in the position of the nuchal plate. The plastron has the same form and
degree of development in relation with the carapace as in living species of
the genus. It is truncated in front, and notched behind.

Although the sutures of the shell are conspicuously visililc, the bones or
])lates are all closely united, and the specimen appears to have been nearly or
quite in theadult condition. No lines of successive growth are visible on the
plates, which are everywhere smooth. The position or boundaries of the
scutes are indicated by deeply marked grooves.

Ten vertebral plates appear to constitute the series, the connection of the
last two in the specimen being destroyed. In form and proportians they bear
a near likeness to those in ' emydes in general. They are rather wider pro-
portionately than those in the specimen first referred to E. Stevemonianm,
Init otherwise are sufficiently alike to pertain to the same species.

As usual, the first vertebral plate is longest; then follows the third. The
second, fourth, and tilth are nearly equal. The others, to the eighth, succes-
sively diminish. The second vertebral plate is as wide at its fore part as it
is long, but the succeeding two plates are considerably longer than wide.

144

The fiflli is as wide as it is long, and the remaining plates are considerably
wider than long.

The costal plates have about the same form as in recent species of the
genus, but the first one is of greater proportionate breadth. Besides the
nuchal plate, it articulates with four marginal plates. The remaining costal
plates are of nearly uniform width as in recent eraydes.

The second costal plate articulates with the fourth and fifth marginals ;
the third, with the fifth and the anterior angle of the sixth marginals ; the
fourth, with the sixth marginal alone ; the fifth, with the sixth and seventh
marginals ; the sixth, with the seventh and eighth marginals ; the seventh, witli
the eighth to the tenth marginals inclusive, and the eightli with nearly the
whole of the tenth and tlie angle of the eleventh marginals.

The marginal plates have nearly the same form and proportions as in recent
emydes.

The nuchal plate also has nearly the form and proportions as in the latter.
The pygal plate, likewise, has the same form, but is proportionately smaller.

The vertebral scute-tracts have nearly the same form as in living species of
Emys, but the intervening ones are longer than wide. They are proportion-
ately somewhat narrower than in the specimen first referred to E. Steven-
sonianus.

The first vertebral scute at its fore part extends outwardly nearly to the
line between the first and second marginal scutes, and in this position is
widest.

The last vertebral scute, at its posterior border, crosses the last vertebral
plate a short distance back of the middle. In recent species of Emys it
impresses the pygal plate.

The costal scutes resemble those of ordinary emydes, and as in these
impress the marginal plates at their conjunction with the corresponding scutes.

The nuchal scute is comparatively short and wide. The specimen being
imperfect at the back part prevents us from ascertaining positively whether
there existed a pair of pygal scutes as in living emydes, but an apparent curve
upon the bone renders it probable that two also belong to the extinct species.

The marginal scutes resemble those of recent emydes, but the anterior are
wider than high, and the posterior, including the pygal scutes, are higher
than wide.

The fore part of the plastron has a half-oval outline shghtly projecting, and

145

fruiicated at the extremity as in ordinary emydes. The back part likewise
has the same form as in the latter, and is also notched at the extremity.

The pedicles are less elevated than in most recent emydes, and arc rather
wider to the acute border of the carapace.

The constitution of the plastron is so nearly like that of ordinary living
emydes as hardly to need special description.

The entosternal plate is nearly lozenge-shaped, and is widest transversely.

The humeral scutes at their posterior border barely cross the posterior
extremity of the entosternal bone.

The pectoral and alxlominal scutes extend outwardly to conjoin the margi-
nal scutes upon the marginal bones. In ordinary recent species of Emys the
marginal scutes extend upon the hyosternal and hyposternal plates to join the
pectoral and abdominal scutes.

The axillary and inguinal scutes are large, and impress each a marginal
and a sternal plate.

The length of the carapace in a curved line is within half an inch of a foot
and a quarter; its breadth, in the same manner, 11 inches; in a straight line
it is little over a foot in length and about 10 inches in breadth. The plastron
is less than a foot in length, and its pedicles measure, fore and aft, 4| inches.

5. The specimen originally referred to Emys Haydeni is represented in
Fig. 6, Plate IX. It consists of a portion of the carapace attached to a mass
of indurated clay, and was obtained near Fort Bridger, Wyoming, during Pro-
fessor Hayden's exploration of 1870. Since the specimen was figured, addi-
tional portions of the shell have been found which allow the restoration of
the fore part of the carapace. It belonged to a larger individual than the
specimen first attributed to E. Jeanesi, and from the appearance of the mar-
ginal border of several of the costal plates to a less mature one.

The form of the carapace in front and its constitution in detail are very
similar to the corresponding portion in the former specimen attributed to E.
Jeanesi. The proportions of the vertebral plates is more nearly as in the lat-
ter than in the specimen attributed to E. Stevensonianus.

An apparently important difference between the fossil under examination
and the one. attributed to E. Jeanesi is the less uniformity of width of the
intermediate costal plates. These alternately become wider and narrower
toward their outer extremities, whereas in the specimen referred to E. Jeanesi
fliey are nearly uniform.
19 G

146

As peculiarities of the Ibssil, tiie fourth vertebral plate is octagonal, and
the fifth one in consequence quadrate.

The second and third vertebral scute-tracts are much longer than wide,
and proportionately much longer than in the former specimens. The anterior
division of the second vertebral scute forms three sides of a square ; and the
posterior groove defining the third scute crosses the sixth vertebral plate
instead of the fifth as in the other specimens.

The peculiarities indicated in the fossil under examination I regard as being
of an individual character and in some degree anomalous.

A fragment of the fore part of the plastron accompanying the specimen
referred to E. Haydeni, and apparently belonging to the same individual,
resembles the corresponding part in the specimens previously described, but
is not notched at its anterior truncated border.

6. Another specimen, referable to Emys wijomingensis, consists of a nearly
complete shell except the posterior third of the carapace. It was discovered
by Dr. Carter in the bluffs of the Cottonwood, seven miles from Millei'sville,
in the vicinity of Fort Bridger, Wyoming, and presented by him to the
Academy of Natural Sciences of Philadelphia. It is occupied in the interior
with a greenish-gray sandstone, including indurated clay pebbles. In form
and size it approaches closely the specimen first referred to Emys Jeanesi.
In the forni and proportions of its vertebral scute impressions it more nearly
resembles the specimen originally referred to E. Haydeni. The intermediate
ones are, however, more strongly double sigmoid at their lateral borders; the
fore part of the second vertebral scute is less square; and the anterior border
of the third is strongly bowed forwarxl instead of being nearly straight.

An accidental fracture of the specimen across the posterior third exposes
to view the lateral supports of the carapace ascending from the plastron.
These are much wider than in any of the living emydes, and approach in their
proportions those of the living fresh-water turtle Batagur, of India.

7. A seventh specimen oi E. wyomingensis consists of an intermediate ])or-
tion of a carapace and nearly the whole of the sternum. It was obtained by
Dr. Carter in the vicinity of Fort Bridger, and presented by him to the
Academy of Natural Sciences of Philadelphia.

The vertebral plates of the carapace are in general of proportionately greater
l:)readth in comparison with the length than in the former specimens, and in
this respect most nearly approach the one which was referred to E. Hay-

147

deni. The vertebral scute impressions likewise most nearly resemble those
of the latter but are proportionately broader, and the posterior ]3order of the
third vertebral scute crosses, as usual, the fifth vertebral ])late.

The interior of the carapaceal specimen being freed from matrix, exhibits
the costal plates with strong, well-developed costal capitula.

The plastron is flat ; rather more strongly notched at its posterior extremity
than in the former specimens in which it is preserved.

The thickness of the costal plates ranges from 2 to 4-i lines. The thick-
ness of the hyposternal plates internally ranges from 5^ to 8^ lines.

8. An eighth specimen, consisting of the greater part of a plastron with
fragments of the carapace, was ol)tained by Dr. Carter near Lodge-Pole Trail,
thirteen miles southeast of Fort Bridger, and presented to the Academy of
Natural Sciences.

y. A fragment of a carapace, from Grizzly Buttes, presented to the Acad-
emy of Natural Sciences l)y Dr. Joseph K. Corson, United States Army,
has the intermediate scute impressions much longer than the width, not more
so, however, proportionately, than in the nearly complete specimen numbered
as the sixth.

10. A similar fragment of an apparently young specimen, presented Ijy
Dr. Carter, has the second vertebral scute impression nearly equal in length
and breadth ; and the third one is but little longer than the breadth. Their
lateral grooved borders are strongly double-sigmoid.

11. Part of a carapace and. plastron of a still younger specimen, obtained
]>y Dr. Carter near Lodge-Pole Trail, twelve miles southeast of Fort Bridger,
nearly agrees in the form and proportions of its corresponding vertebral scute
impressions with that last described. The second is nearly of equal length
and breadth; the third and fourth are wider than the length. In its details
of structure it accords sufficiently with the older and more complete specimens
to render it probable that it pertained to the same species, except that the
carapace is obtusely cnrinated its entire length. The entosternal bone is more
rounded at its fore part than in previous specimens, and its length is alxtut
equal to the breadth.

12. A fragment of a plastron of another young individual, from the same
locality and gentleman as the preceding, nearly agrees with the corresponding
part. The entosternal is a httle longer than liroad, and is pyriform, with lat-
eral projecting angles.

148

13. A specimen, apparently of a still younger individual of the same species,
presented to the writer by Dr. Carter, was about the size of the palm of the
hand. It consists of small portions of the carapace and more than half the
plastron. The carapace is carinated as in specimen No. 11, and otherwise
agrees with this in its details. The plastron has the same form as in the
more complete and older specimens previously indicated, but the entosternal
is more pyriform, considerably longer than wide, and the posterior defining
groove of the pectoral scute crosses its middle.

If it is admitted that the specimens Nos. 11 and 13 belong to Ejuijs
wyomingensis, it would appear that the carinated condition of the carapace is
a juvenile character, disappearing with growth. It would also appear that
during growth the breadth of the entosternal plate became proportionately
greater in relation with its length

None of the specimens viewed as young ones exhibit upon the surface lines
of growth, except the sternal one, No. 12, in which they are feebly marked.
A distal fragment of several posterior costal plates of specimen No. 11, in the
immature appearance of its border, clearly proves its youthfulness.

Besides the thirteen characteristic specimens of E. loyomingemis which
have been described or mentioned, fragments of many others are contained
in the collections I have had the opportunity of examining. From their com-
parative frequency, this appears to have been the most abundant of the fresh-
water turtles of the Bridger Tertiary epoch.

14. Since writing the foregoing, I have had the opportunity of examining
another specimen of Emys wyomingensis in the possession of Dr. Ilirani
Corson, which was sent to him from Fort Bridger by his son, Dr. Joseph K.
Corson. Tlie specimen consists of a nearl}' complete shell except the posterior
fourth of the carapace. It is a little smaller than the fourth-described speci-
men, represented in Plate X, and is crushed and distorted nearly in a similar
manner.

The most striking peculiarities of this, which may be distinguished as the
fourteenth specimen, are the unusual depth and width of the scutal grooves
of the carapace and the proportionate shortness and breadth of the costal
scute areas.

The intermediate vertebral plates to the first and fifth are absolutely longer
and narrower than in the ratlier larger fourth-described specimen. The costal
plates are shorter, and (he second to (he four(h, inclusive, are broader. The

149

first and second vertebral scute aieas are wider and the third one lon<rer.
The forms of the plates and scute areas indicated are nearly the same in both
specimens.

The plastron is slightly convex in both directions, and its extremities for
half the length are more parallel at the lateral borders than in the fourth-
described specimen. The axillary and inguinal scute areas are longer and
narrower than in the latter, and somewhat modified in form. The length of
the plastron in the median line is 11 inches. Other measurements in detail
are given in the annexed table under the head of specimen 14.

Comparative measurements of the specimens referred to Emys wyomingcn-
sis are as follows :

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154

BAPTEMYS.

A peculiar iiud interesting genus of extinct emydiform turtles, apparently
intermediate in its characters to the existing American genera Dermatemys
and Staurotypus, is founded on remains in the Bridger Tertiary formation of
Wyoming.

In shape and constitution, the shell of Baptemys (Plate XII) approaches
most nearly that of Dermatemys^ more especially the carapace, while the
sternum partakes of the character of that of Staurotypus.

The carapace is oval in outline, apparently not wider behind than in front,
and with the prominence or convexity about equal to half its breadth. The
convexity is nearly uniform fore and aft, and laterally to the flexure of the
marginal plates. The anterior border is bai'ely evei'ted and is thick and
rounded. The imperfection of the fossils prevents a determination whether
the posterior border departed from the general convexity of the liack of the
shell. The surface formed hy the first and second marginal plates is feebly
depressed.

A median carina or thick rounded ridge starts upon the sixth vertebral
plate and extends backward.

Eleven vertebral plates enter into the constitution of the carapace. Those
anteriorly are proportionately much longer than in emydes. They also appear
proportionately of greater extent than in Dermatemys.

The first vertebral plate is oblong, somewhat narrowed behind, and with
the sides convex. Those to the sixth inclusive are hexagonal coffin-shaped.
From the fifth they rapidly decrease in length to the eighth inclusive, and
then increase again to the last. The seventh is niore uniformly hexagonal
than the others. The ninth is quadrate and wider than long. The tenth is
quadrate, widest behind, with the lateral borders convex and the back border
concave.

Tlie costal plates arc like those of Dermatemys, and as in this widen out-
■ wardly more than in ordinary emydes in accordance with the greater convexity
of the carapace.

Tlie nuchal plate and marginal bones, so far as preserved, appear to be
nearly as in Dermatemys.

The scute impressions of the carapace, as in the latter, are not defined by
such deep grooves as are usually observed in emydes.

156

The vertebral scute impressions have the same fonu niid general [iropor-
tions as in Dermatemys. The first is wide, urn-like in outline, and is broader
than long. The succeeding three are quadrate, with tlie length greatly ex-
ceeding the breadth, and with the usual lateral brace-like or double-sigmoid
borders. The last impression narrows for a short distance and then diverges
in the usual manner.

The costal scute impressions resemble those of emydes and extend farther
upon the marginal bones than in Dermatemys, nearly reaching the middle of
their outer face at the sides of the carapace, as far back as they are preserved
in the fossils, as well as in front.

The position of the nuchal scute is not preserved in the fossils, but the
part immediately contiguous in one of them indicates tliat it had about the
same proportions as in Dermatemys.

The marginal scute impressions about occupied the lower two-thirds of
the outer aspect of the marginal plates. The line intervening to the first
two marginal scutes is continuous with that between the first vertebral and
the succeeding costal scute. '

Considering the striking resemblance of the carapace of Baptemys to that
of Dermatemys, it is not a little surprising to observe so much ditference in
the plastron, though this also is nearly alike in the scute impressions.

Compared with that of Dermatemys, the plastron is remarkably small,
leaving proportionately much larger spaces in advance and behind the bridges
for the movements of the animal. As before intimated, it is intermediate in
character to that of the last-named genus and that of Staurotypus. The
pedicles are intermediate in extent to what they are in the two genera just
mentioned. The fore part of the plastron has nearly the same shape as in
Dermatemys, but is widely emarginate at the extremity, and it is thick
and rounded at the border instead of being acute as usual in emydes. The
back part of the plastron is narrower than in Dermatemys, but less so than
in Staurotypus. It terminates in a rounded extremity as seen in Fig. 2,
Plate XII. In Dermatemys, it ends in a wide notch ; in Staurotypus, in a
point.

The entosternal lione is proportionately as large as in Dermatemys, and has
nearly the same form. " The same may be said to be the case w'ith the epister-
iials, (Fig. 6, Plate XV,) except that their anterior border is more conca,ve.

156

Tlie liyostcrnals and hyposlcrnals have nearly the same extent. Their
intervening suture crosses the sternum near the middle of the pedicles.

Dr. Gra}-, who established the genus Dermatemys, represents the South
American species D. Mawii, with a pair of gular scutes. D. Berardii, of
Mexico, is represented by Dumeril as possessing a single symmetrical gular
scute, and this also is the case in two shells from Balize River, Yucatan, and
Tabasco, Mexico, described by Professor Cope as pertaining to another species
whicli he has named D. ahnormis.

In Baptemys there is no trace of separation of gular scutes from the
humeral scutes as indicated in Fig. 6, Plate XV. The grooves defining the
latter from, the pectoral scutes occupy nearly the same position as in Derma-
temys, crossing nearly through the middle of the entosternal plate.

In Emys the gular and humeral scutes fold deeply upon the upper surface
of the sternum, but in Baptemys, as is also the case in Dermatemys, the cor-
responding scutes fold only to the upper edge of the rounded border of the
sternum.

The intervening grooves of the pectoral, abdominal, femoral, and caudal
scutes nearly equally subdivide the sternum of Baptemys.

The pectoral and abdominal scutes extend upon the sternal jjedicles, and
are there separated from the marginal scutes by large intervening scutes, as
in the sea-turtles and in Dermatemys. In the same position in Dermatemys
ahnormis there are four of these scutes. In one of the specimens I have had
the opportunity of seeing there are four of these scutes on one side and three
on the other; but in this case it appears evident that the reduction is not the
usual condition in the species.

There are three scutes on the sternal bridge of Baptemys which succes-
sively increase in size. The first or axillary scute joins the fourth and fifth
marginal scutes and the pectoral scute. The middle or submarginal scute
is hexagonal, widest transversely, and it joins the fifth and sixth marginal
scutes and the pectoral and abdominal scutes. The third or inguinal scute,
nearly twice the extent of that in advance, is also hexagonal. It extends
across the hyposternal upon the hyosternal plate, and joins the sixth and
seventh marginal scutes and the abdominal scute, an outward prolongation
of which to the inguinal notch separates it from the femoral scute.

The axillary fossa reaches as far back as the posterior third of the fourth

167

marginal bone ; the inguinal fossi extends forward nearly on a line witli the
posterior border of the sixth marginal bone.

The interior of the fossils being occupied by the rocky matrix, all the
internal anatomical details are concealed from view.

Baptemys in the relatively smaller size of the plastron to the carapace, and
in the presence of submarginal scutes to the sternal bridges, is more nearly
related to the marine turtles than the genus Emys.

Baptemys appears also to have been nearly related with the equally ancient
and extinct genus Pleurosternon, of the English Tertiary formation. In
this the vertebral scute areas of the carapace are remarkable for their breadth,
which considerably exceeds the length, whereas in Baptemys the intermediate
Vertebral scute areas are much longer than liroad. The plastron in Pleuro-
sternon is intermediate in its proportions to that of Emys and Baptemys, and
has an additional pair of bones entering into its composition which do not
exist in the latter genera. In Pleurosternon a pair of integular scutes inter-
vene to the gular scutes ; in Baptemys there appears to be no distinction of
gular scutes from humeral scutes. In Pleurosternon, as in Baptemys, large
accessory or submarginal scutes intervene to the comparatively large axillary
and inojuinal scutes.

Baptemys wyomingensis.

The species thus named, as well as the genus, was first characterized from
a beautiful specimen of the turtle-shell, discovered by Mr. 0. C Smith, of
Leverett, Massachusetts, while engaged in the service of the Union Pacitic
Railroad Company, near Fort Bridger, Wyoming Territory. The specimen
was loaned to Professor Hayden, by whom it was sent to the writer for exam-
ination. It is represented in Plate XII, one-third the natural size.

The specimen consists of a shell which nearly retains its original form, but
has lost the front marginal plates on one side, all those behind, most of those
of the left, and the front part of the plastron. It is black, as is frequently
the case with the fossils from the same locality ; and it is filled in the in-
terior with a gray sandstone mingled wath coarse pebbles of indurated bluisii
clay.

In its perfect condition the shell has measured about a foot -and a half in
length, and in breadth about a foot. Following the curvature of the carapace

158

fore and aft, it has measured about 20 inches in length, and the transverse
arch from a level has been nearly as great.

The length of the plastron has been about 11^ inches; its breadth from
its sutural junction with the carapace is 9 inches.

The sides of the plastron slope inwardly to a moderate degree. The pedi-
cles are nearly on a level with the rest of the plastron, but are somewhat
prominent in front and slope backward, and are concave approaching the
inguinal fossaj. The rise of the shell appears mainly to commence in the
marginal bones from the sternal pedicles ; to what degree is uncertain, as
this part of the fossil is somewhat crushed inwardly. The rise is greater
anteriorly, and gradually appears to subside liehind.

The fore and aft extent of the pedicles is 4^ inches. The length of the
anterior extension of the plastron has been about 3J inches ; its breadth at
the bottom of the axillary fossse is 5J inches. The length of the posterior
extension of the plastron is a little more than 3^- inches, and its width at the
bottom of the inguinal fossae nearly 4^ inches.

The marginal bones appear more abruptly bent to join the sternal bridge
than in Dermatemys, but the difference is partially due to the crushing
inward of the under part of the shell in the fossil.

A second specimen of the shell of Baptemys wyomingensis was subse-
quently discovered during' Professor Hayden's exploration of 1870 at Church
Buttes, Wyoming. The shell is of a different color, and is filled with and
partially imbedded in a different matrix from the former specimen. The
bones are brown, and the matrix consists of a very hard sandstone. The
specimen, though fiir less complete than the former, fortunately retains one-
half of the anterior part of the plastron. Most of the carapace is lost or
imbedded in the hard rock. The sternum on one side from its fore extremity
to the commencement of the xiphisternal bone, together with the pedicle and
its characteristic scute impressions, is well preserved.

The measurements of this second specimen indicate an individual of the
same size as the former. Slight differences existing between corresponding
parts of the two appear to be variations only of an individual character. In
the second specimen tlie large inguinal scute passes just over the back edge
of the hyosternal plate, while in the former one it extends upon it for half
an inch.

159

Measurements derived mainly from the more complete specimen arc as

follows.

Length.

First vertebral plate . . .
Second vertebral plate.
Third vertebral plate . .
Fourth vertebral plate.
Fifth vertebral plate . . .
Sixth vertebral plate .
Seventh vertebral plate
Eighth vertebral plate .
Ninth vertebral plate .
Tenth vertebral plate. .

Lines.
27
22
23
22
32
17
10
7
9
13

Breadth.

Linen.
]3
14
14
. 14
15
IG
17
12
14
16

Leuffth.

Width
iuterually.

Width
externally.

F'irst costal plate . .
Second costal plate
Third costal plate. .
Fourth costal plate .
Fifth costal plate .
Sixth costal plate .
Seventh costal plate

Lines.

45
GO
70
73
GO
GO
47

Lines.

2G
24
24
22
20
17
15

Lines.
37
2G
27
24
30
22
20

The nuchal plate fore and aft has been about 2f inches ; its breadth about
an inch greater.

The marginal bones, so far as preserved, appear to have nearly the propor-
tions and aspects as in Dermatemys. Their vertical measurement is about
2 inches, and their width about the same.

The measurements of the scute impressions are as follows:

lireadth.

First vertebral scute impression . .
Second vertebral scute impression
Third vertebral scute impression . .
Fourth vertebral scute impression

First costal scute at middle

Second costal scute at middle

Third costal scute at middle

Lines.

52
30
33
32
5G
4G
4G

160

The episternals at their uiiier border measure 1 inch ia length ; at their
posterior extremity 10 lines.

The entosternal bone is 2J inches fore and aft, and 2f inches wide.

In the better preserved of the two specimens the plastron presents the
irregularity of having the left hyposternal and xiphisternal near half an inch
more produced forward than npon the right side, as seen in Fig. 2, Plate XII.

Measurements of the remaining sternal bones are as follows :

Lines.

Length of right hyosterual internally 30

Length of left hyosterual internally 25

BreadtJi of hyosternals at middle 58

Length of hyposternals internally 34

Breadth of hyposternals at middle 52

Length of right xiphisternal internally 34

Length of left xiphisternal internally 40

Breadth of anterior border 24

Measurements of the scutes are as follows :

Lines.

Length of gular-humeral scute internally 28

Breadth of gular-humeral scute posteriorly 26

Length of pectoral scute internally 18

Breadth of pectoral scute posteriorly 36

Length of abdominal scute internally 29

Breadth of abdominal scute posteriorly 28

Length of femoral scute internally 26

Breadth of femoral scute posteriorly 22

Length of caudal scute internally 27

Axillary scute obliquely from within outward 32

Axillary scute at posterior border 13

Middle scute of sternal bridge fore and aft 17

Middle scute of sternal bridge at middle, transversely 25

Inguinal scute fore and aft 32

Inguinal scute at anterior border 13

Inguinal scute at middle between prominent angles , 29

BAENA.

By this name I have distinguished a remarkable genus of turtles, indicated
by remains in the Bridger Tertiary beds. It partook of characters of the
snappers or chelydroids, the terrapins or emydoids, and the sea-turtles or
chelonioids. The specimens upon which the genus is founded consist of shells,
which are mostly so much crushed and distorted as to render it somewhat
uncertain as to their exact original and perfect form. They were apparently
about as prominent as in our snapper, and had nearly the same outline of shape.
Tlie middle of the carapace is not depressed as in the latter, but is somewhat

161

flattened, and forms a continuous convexity with tlic sides. The posterior
extremity presents a deep emargination as in the snapper, and on each side is
notched likewise as in the latter.

The plastron of Baena is emydoid in character, and in its degree of develop-
ment in relation with the carapace approaches that of its associate genus Bap-
temys. As in this, large spaces exist between the extremities of the plastron
and carapace, but comparatively of much less extent than in Chelydra. The
pedicles of the plastron are immovably conjoined with the carapace. They
are as wide relatively as in the emydoids, but are much longer. The two
extremities of the plastron are nearly alike in shape, being tongue-like and
feebly emarginate at the end.

The number, arrangement, and general form of the corneous scutes of the
carapace appear to have been the same as in Emys and Chelydra. The plastron
exhibits two pairs of gular scute areas, which, together with the other scute
areas, made seven pairs to the plastron. In addition to these the pedicles
exhibit a row of scute areas between the former and the marginal scute areas
of the carapace, as in the sea-turtle, the snapper, Dermatemys, and Baptemys.

A feature which may be regarded as a character of Baena is the obliteration
• of the sutures, and the shell at maturity has the bones so co-ossitied that their
original boundaries cannot be traced.

The true ribs or costal arclies, connate with the costal plates, are remark-
ably prominent in Baena, and the costal capitula are well developed. In
several specimens, in which portions of the carapace. arc broken away, the
mass of rock within exhibits deep concave grooves indicating the former
position of the rib-arches.

The sustaining columns of the carapace, springing as processes from the
hyosternal and hyposternal bones of the plastron, are of great comparative
breadth, and subdivide the interior of the shell into three compartments as in
tlie Batagur, a genus of fresh-water turtles now living in India.

Baena arenosa.

The species thus named was originally founded on a specimen consisting
of a nearly complete turtle-shell discovered at the junction of the Big Sandy
and Green Rivers, Wyoming, during Professor Hayden's exploration of 187U.
The specimen is represented in Figs. 1, 2, Plate XIII.

The shell, besides appearing to be in some degree crushed downward or
21 G

1G2

flattened, has lost the fore part and right border of the carapace. The plas-
tron, less injured, has lost its anterior extremity.

The outline of the carapace appears to have been broadly oval; and the
shell was apparently not more elevated than in our common snapper.

All the bones of the carapace and plastron are so intimately co-ossified that
the position of the former sutures cannot be detected. The grooved bound-
aries of the scutal areas are, on the other hand, vv^ell marked.

The carapace corresponding with the position of the intermediate vertebral
scutes is flattened and slightly depressed at the middle. It is most prominent
along the lateral boundaries of the vertebral scutes. In the position of the
last of the latter it is most prominent at the middle. No distinct carination
exists, but a feeble and widely interruj^ted ridge occupies the median line of
the carapace, scarcely noticeable were it not better developed in other speci-
mens. The sides of the carapace slope evenly outward to the rounded flex-
ure of the lateral marginal plates.

The posterior marginal plates are notched as in the snapper, and are slightly
recurved at the prominent ends. Between the last pair, of marginal bones a
wide concave emargination exists, as in Chelydra, but of less depth.

The intermediate vertebral scute tracts are nearly square, and are as broad •
as, or a little broader than, long. The lateral grooves have the usual brace
form. The groove between the second and third tracts is convex forward ;
the succeeding' one much less so; and that between the fourth and fifth tracts
is much produced forward with a mammiform outline.

The costal scute tracts are nearly like those of Emys and Chelydra. Their
grooves are directed nearly parallel outwardly, except the extreme back and
front ones.

The plastron appears quite flat and nearly on the same level with its pedi-
cles, but this condition is evidently in some degree the result of accidental
l^ressure from above. The posterior extremity is broad, linguiform, with the
end slightly and concavely emarginate.

The pectoral scute impressions, as in the Chelydra, are larger than any
others of the plastron. They extend outwardly on half the breadth of the
sternal bridges. Tiie anterior groove is directed outwardly on a level with
the bottom of the axillary fossae, and near its end turns abruptly and obliquely
forward to the edge of the latter.

The abdominal scute impressions, shorter than those next in front and

163

behind, extend upon the posterior half of the breadth of the sternal bridges.
Their posterior groove is directed obliquely outward and backward to the
bottom of the inguinal fossae.

The femoral are considerably lai'ger than the costal scute impressions, and
defined from them by a sigmoid groove.

The bridges of the plastron present a row of four large scutal areas inter-
vening between the pectoral and abdominal scute areas internally, and the
marginal-scute areas of the carapace externally. The first and last of these
may be regarded as homologues of the comparatively small axillary and ingui-
nal scute areas of Emydes; the intermediate ones are superadded.

The axillary scute area, partially broken away in the specimen, appears to
have had four borders, of which the anterior formed the outer boundary of
the axilla, and the internal joined the pectoral scute area.

The second submarginal scute area, the smallest of the series, is quadrate,
and internally joins the pectoral scute area. The succeeding submarginal
area, larger than those in advance, is pentagonal, with the two shorter sides
forming a projecting angle joining the pectoral and abdominal areas.

The inguinal scute area, larger than the others, has four borders, of which
the internal joins the abdominal area, and the posterior bounds the greater
part of the bottom of the inguinal space.

The surface of the carapace is somewhat irregular ; that of the plastron is
more regularly and minutely roughened or fretted in appearance.

A second nearly complete specimen of a shell of Baena was discovered by
Dr. J. Van A. Carter at Church Buttes, on Black's Fork of Green River, three
miles north of Fort Bridger, and was obligingly sent to the writer as a gift.
The shell, like the former one, is considerably crushed, so as to render an
exact determination of its original form uncertain. It approximated the other
specimen both in shape and size, and, like it, has all the bones so completely
co-ossified that their limits are obliterated.

This second specimen presents several differences from the former one,
which led to its having been considered as pertaining to another species, to
which the name of B. affinis was given. Additional specimens since obtahied
and exhibiting other variations have led to viewing all of them as belonging
to a single species.

The carapace measures 13 inches in length following the curvature. Its
anterior portion, preserved in the specimen on one side, has a rather obtuse
border, and is not recurved. In front it is prominent, as far as seen in the

164

specimeii, currespoiuliug with the position of what appears to be tlie outer
portion of the nuchal scute area. The latter apparently is of great width, at
.least an inch at its conjunction with the first vertebral scute area.

The latter and tlic last of the series are prominent in the median line, where
they form a thick, rounded ridge. A low interrupted ridge extends along the
median line of the carapace, which is barely evident in the first-described
specimen. The short divisions of the ridge are flanked by equally long fusi-
form elevations slightly divergent forward. In addition, the carapace is
rather irregularly prominent along the position of the lateral grooves of tlie
vertebral scute areas. The intermediate vertebral scute areas are proportion-
ately narrower than in the first specimen. The second and third are slightly
longer than wide; the fourth a little wider than long; and the first and last
in width considerably exceed the length.

The jilastron is preserved nearly complete, and is represented in Fig. 3,
Plate XIII. It appears as if originally it had been less flat than in the former
specimen, as, inde])endently of fractures, it turns up more at the extremities
as well as at the bridges.

The anterior extremity, which is lost in the former specimen, affords an
opportunity of completing our knowledge of the plastron. It is shorter and
narrower than the posterior extremity, but is nearly like it in shape. The free
border is obtusely rounded, and is slightly more thickened and prominent at the
divisions jJroduced by the scute impressions. These do not mark the upper sur-
face as in the Emydte. The lower surface exhibits one of the most remarkable
peculiarities of the genus, which is the possession of two pairs of gular scutes.

The first pair of gular scutes are comparatively small, and are defined poste-
riorly, in, the usual manner, by oblique grooves diverging at an angle' of 45°.

The second pair of gular scute impressions escaped my notice until I had
seen several additional specimens. As this did not occur until after the draw-
ing of Fig. 3 was made, they are not there represented. They are seen in
Fig. 1, Plate XV, which was subsequently and more accurately drawn from
the same specimen. They are rather larger than the first [)air, and are
defined posteriorly by a serpentine groove directed outwardly nearly from the
same point as the grooves in advance.

The remaining scute areas of the plastron are nearly like those of the pre-
ceding specimen, except those covering the pedicles.

Only three scutes covered the latter in the second specimen, the one cor-
responding with the first submarginal scute area of llie first specimen being

165

deficient. Ta conscqueticc of its absence, a modification of tlie outlines ol' t he
contiguous ones resulted. The posterior groove of the axillary scute, and the
anterior groove of the area corresponding with the second submarginal scute
in the first specimen, instead of being transversi; are oblique and join each
other at an angle externally. The posterior two scutal areas also dilfer from
those of the first specimen in being separated l:)y a groove directed obliquely
outward and backward instead of nearly transversely.

The surface of the plastron exhibits tlie same minutely fretted appearance
as in the tbrnier specimen.

In the perfect condition the two specimens of Baena which have been de-
scribed differed but little in size. The length of the carapace in a straight line
has approximated 13 inches, the breadth 9 or 10 inches. The length of the plas-
tron is 11 inches; its breadth to its conjunction with the carapace about 8 inches.

A third and less perfect specimen of the shell ef Bac7ia areiwsa, consisting
of the central portion of the carapace and nearly the corresponding portion
with the anterior extremity of the plastron, was found l^y Dr. Carter on
Henry's Fork of Green River, and presented by him to the Academy of
Natural Sciences.

This specimen had about the same size as the previous ones, and like them
has all the bones completely co-ossified. The median ridge of the carapace is
more distinct than in the other specimens, and its divisions appear more or
less distinctly to mark the position of the vertebral plates, while the lateral
diverging prominences also appear to mark the sides of these plates. •

The intermediate vertebral scute areas are intermediate in proportions to
those of the former specimens.

The surface of the plastron is smooth and exhibits no trace of the minutely
fretted condition observed in the former specimens. The grooves defining
the sternal scute impressions, the median groove as well the more transverse
ones, are less regular in their course than in the other specimens.

The anterior extremity of the plastron, represented in Fig. 2, Plate XV, is
flat, and exhibits the second pair of gular scute areas larger than in the former
specimen in which they exist, while their more tortuous back groove starts
from the median groove a half inch behind that in front. The rounded bor-
der is more prominent in the position of the gular scute impressions than in
the former specimen.

A small part of the sternal bridges retained in the specimen shows a por-

1(56

tioii of ilie second subinarginal scute area witli an internal projecting angle
intermediate in extent to that of the former specimens. On one side, also, a
small portion of the tirst submarginal area is retained, and this appears to
indicate that it was nearly of the size and shape of that in the first-described
specimen of Baena.

Comparative measurements of the three described specimens of Baena
arenosa are as follows :

Leugth of first vertebral scute at middle

Breadth of first vertebral scute at middle

Leugth of second vertebral scute at middle

Breadth of second vertebral scute at middle .

Leugth of third vertebral scute at middle

Breadth of third vertebral scute at middle

Length of fourth vertebral scute at middle

Breadth of fourth vertebral scute at middle

Length of fifth vertebral scute at middle

Breadth of fifth vertebral scute at middle

Width of first costal scute internally

Width of second costal scute internally

Width of third costal scute internally

Width of fourth costal scute internally

Length of anterior prolongation of the plastron

Breadth at base of anterior prolongation of the plastron . .

Length of posterior prolongation of the plastron

Breadth at base of posterior i^rolongation of the plastron .

Breadth of pedicles of plastron

Length approximately of pedicles of plastron

Leugth of gular scutes internally

Breadth of gular scutes at back border

Length of humeral scutes internally

Breadth of humeral scutes at back border

Length of pectoral scutes Internally

Breadth of pectoral scutes at middle

Breadth of pectoral scutes at back border

Length of abdominal scutes internally

Breadth of abdominal scutes at middle

Breadth of abdominal scutes at back border

Length of femoral scutes internally

Breadth of femoral scutes at back border

Length of caudal scutes internally

Fore and aft diameter of first scute of pedicle

Fore and aft diameter of second scute of pedicle

Fore and sjft diameter of third scute of pedicle

Fore and aft diameter of fourth scute of pedicle

Liues.

36
30
35
37
29
37
32
48

37
32
21

48
50
62
26

24
32
41
31
15
41
34
28
21
21

16
20

Lines.

22
36

26.

24
20

Lines.

35
32
34
32

38
30

52
56
24
10
15
21
22
22
50
33
20
44
28
24
19

1G7

A fourth specimen referable to Baeiia arenosa consists of a small portion of
the carapace with a large portion of the plastron, from Henry's Fork of Green
River, found by Dr. Carter, and presented by him to the Academy of Natural
Sciences of Philadelphia. This exhibits no peculiarity, excepting that the
scutal grooves of the plastron are more irregular in their course than in the
preceding specimens. The median groove of the plastron is especially tor-
tuous, while in the other specimens it is nearly straight. A retained portion
of one of the sternal bridges exliibits evidences that four scufes impressed
them, arranged nearly as in the first-described specimen of Baena. The sur-
face of the plastron is less smooth than in the previous specimen, but it does
not present the fretted appearance of the two former ones.

A fifth specimen, apparently referable to B. arenosa, consists of the anterior
extremity of a plastron, represented in Fig. 3, Plate XV. It was found at
Grizzly Buttes by Dr. Joseph K. Corson, and by him presented to the
Academy of Natural Sciences. It would appear from its size as if it had
belonged to a larger individual than the preceding specimens. It is nearly
flat, or in a trifling degree convex, and is smooth, or without any appearance
of fretting. It exhibits the four gular scute areas of unequal extent.

Another specimen, consisting of the anterior extremity of a plastron, appar-
ently of 'a young animal of the same species, is represented in Figs. 4, 5,
Plate XV. The specimen was found at the junction of the Big Sandy and
Green Rivers, Wyoming, during Professor Hayden's exploration of 1870.

In this specimen the sutures are visible, and the contiguous bones defined
The grooves defining the two pairs of gular scutes start all from the same
point, which is near the center of the entosternum. The entosternal bone
viewed below is pyrilbrm, but in the reverse position to that ordinarily
observed in emydcs. Viewed above, it resembles that of the snapper,
(Cheli/dra,) or that of the sea-turtle, {Ckelove.) In front it is received
between the episternals ; behind, it forms two lateral barljs projecting
obliquely outward between the episternals and the hyosternals, and a long,
median, pointed process extending between the hyosternals. The episternals
posteriorly are angular, and are there received into a notch of the hyosternals.

From the matrix of the first-described specimen of the shell of Baena I
obtained a portion of the pelvis, which presents some anatomical points of
importance.

168

Comparative measurements of the anterior extremity of the plastron, where
this is present in the specimens, are as follows :

First
specimen.

Second
specimen.

Third
specimen.

Fourth
specimen.

Sixth speci-
men, yonng.

Length of plastrou to anterior pectoral
groove . ...

Lines.

Lines.
34
30
28
18

Lines.
30
43
28
18

Lines.

■
34

Lines.

Breadth of plastron at anterior pectoral

Breadth of plastron at anterior humeral

Breadth of plastron at middle gular
groove

The pelvis is more expanded above than in Emj^s, and in this respect is
more like that of the snapper. The sacrum represented in Fig. 9, Plate
XVI, is intermediate in its proportions to that of the two genera just men-
tioned.

The length of the sacral vertebrae of Baena, independently of the wings or
transverse processes, exceeds the breadth, the proportions in this respect
according more witli the condition in the terrapin than in the snapper. Tlie
second sacral vertebra is, however, larger than the first, as in the latter turtle,
and the reverse of what it is in the former. The inferior surface of the
bodies of the sacral vertebrse is half cylindroid, depressed at the sides in the
first one, but scarcely so in the second.

The anterior articular surface of the first sacral centrum is moderately
convex ; the posterior articular surface of the second centrum is concave. In
Emys the corresponding surfaces are flat, or nearly so; in Chelydra the ante-
rior one is concave, the posterior convex, with lateral extensions nearly flat.

The proportionate length and robustness of the sacral ala3 of Baena agree
more nearly with the condition in the snapper than in the terrapin. In Emys
the posterior alse are comparatively feeble appendages, and they join the ends
of the anterior alse by means of a hgaraent. In Baena the posterior alse are
strong processes, as in the snapper, and likewise, as in this, join the ends of
the alee in advance by suture, but appear not to be prolonged to join the
ilium.

The innominatum of Baena, as represented in Fig. 8, Plate XVI, is proper-

169

tionately of more robust cliaracter than in Erays. The ilium in filunx! is
more like that of this genus than that ot the snapper, l)ut is proportionately
ol' much greater breadth, the wing being of nearly double the expanse.

The expanded extremity of the first sacral wing articulates with the ante-
rior extremity of the crest of the ilium. In Emys it articulates with the
latter midway to the two prominent extremities of the crest.

The acetabuhim and commencements of the ischiatic and pubic rami pi-e-
sent nothing peculiar from the condition observed in the snapper.

Measurements of the pelvic specimens are as follows :

Lines.

Length of sacrum beneatli the centra 9j

Length of first sacral centrum 4^

Breadth of first sacral centrum .■ 4.J

Length of second sacral centrum 4^

Breadth of second sacral centrum 4?

Breadth of sacrum at first pair of alae 30

Length of first saci'al alae , 13

Length of second sacral alaj 11

Length of innominatum 23

Breadth of crest of innominatum 18

Height of acetabulum C

Breadth of acetabulum 9J

CHISTERNON.

Chisternon undatum.

A large turtle-shell, discovered by Dr. Carter in a chain of buttcs a few
miles from Fort Bridgcr, and presented to the Academy of Natural Sciences
of Philadelphia, was originally described by me under the name of Baena
undata. A careful examination of the specimen has led me to view it as per-
taining to a different and heretofore undescribed genus.

The specimen represented in Plate XIV, one-half of the diameter of nature,
consists of the intermediate portion of a shell, with the extremities broken
away nearly in the position of the broad columns wliich spring from the plas-
tron to support the carapace. Though much fractured, it appears to have
been but little so while it lay imbedded in the deposit from which it was
derived, so that it now retains its orginal form. The upper shell is as mucli
vaulted as in some of the living land-turtles. This form, together with the
thick bone and strong, broad sternal supports, enabled it to sustain tlic grt'ut
weight of superincumbent pressure which has crushed so many of its asso-
22 G

170

ciates. The interior of the shell is occupied by a greenish-gray sandstone,
from which I obtained a pair of sacral vertebrae.

The outline of the shell in its perfect condition was ovoid as in ordinary
Emydes ; narrower and more elevated in front, wider and more depressed
behind. The fore part and sides of the carapace are uniformly convex, but
the hind part appears to have had the margin somewhat recurved. Over the
position of the vertebral scute areas the surface is flat and even and without
a carina. The plastron is flat, but its bridges turn from their commencement
upward and outward to the border of the carapace, which is elevated 2^
inches above the level. The highest part of the shell is nearly 6 inches
above the level of the plastron. The bones of the shell, especially those of
the carapace, appear co-ossified, but not so completely as in Baena arenosn,
for those of the plastron can be distinctly traced.

The intermediate vertebral scute areas have nearly the form and propor-
tions of those of Baena arenosa, and are rather longer than wide. The costal
scutes widened more outwardly than in that turtle, indicating a proportion-
ately greater degree of prominence of the shell.

The lateral marginal scute areas are much like those in Emydes, but the
groove defining them from the costal scute areas exhibits an unusually undu-
lating course, not angular but serpentine or waving.

The number and relative position of the scute areas of the plastron and its
bridges are the same as in Baena, but the median sternal groove defining
them on the two sides is remarkable for its irregular serpentine course,
repeatedly crossing the also somewhat irregular course of the median suture
of the plastron.

The sutures of the plastron being visible, they reveal to us an unexpected
peculiarity, the existence or absence of which cannot be determined in the
shells of Baena arenosa from the total obliteration of the sutures.

The peculiarity in the plastron of Chisternon, to which the genus owes its
name, is the presence of a large triangular bone, added to those which usually
exist in turtles, on each side of the shell. This intercalated or mesosternal
bone commences at the center of the plastron and gradually widens outwardly
to where it conjoins the marginal plates of the carapace at the intermediate
half of the sternal bridge. The four sutures defining the mesosternal plates
from those in front and behind cross the plastron obliquely. A similar bone

171

exists in another extinct genus, the Pleurosternon, dI' the early Tertiary for-
mation of England, but in this it has the shape of a parallelogram.

The sternal bridges of Chisteriiou present four large scutal areas nearly
resembling those of Baena arenosa. They are not quite symmetrical on the
two sides.

The axillary scute area is pentagonal, and is the smallest of the series.
The anterior border is oblique, and. bounds the axillary notch externally.
Two outer borders form an obtuse angle and join the third and fourth mar-
ginal areas. The inner border joins the pectoral area.

The second submarginal area is second in size of the series. It is longer
than l)road, and nearly quadrate, but has its outer angles cut off. The inner
border conjoins the pectoral area; the outer the fourth and fifth marginal
areas.

The third submarginal area is but little larger than the axillary area. It
joins the pectoral and abdominal areas internally, and the fifth and sixth
marginal areas externally.

The inguinal area, the largest of the submai'ginal areas, is obliquely quad-
rate, longer than broad, and with the outer angles cut off. The posterior
border bounds the inguinal notch ; the inner border joins the abdominal area,
and the outer border joins the sixth, seventh, and eighth marginal areas.

The inferior surface of the plastron is comparatively smooth. Striatious
cross the sutures, and elsewhere it presents a finely reticulo-vascular appear-
ance.

The fractured condition of the shell affords us an opportunity of seeing
the strong hyosternal and hyposternal columns which aid in sustaining the
cai'apace. These columns are broad, vertical plates reaching far into the cav-
ity of the shell and dividing it into three compartments, as in the Batagur of
India.

The hyosternal columns are 2\ inches wide from their inner concave bor-
der to the axilla. The aperture of the shell between them is a doorway 3
inches wide near the roof and 4^ inches near the floor. The hyosternal col-
umns, partially exposed in the specimen, appear to be co-extensive with the
anterior supports.

The breadth of the shell of Chisternon undatum, between the lateral
obtuse borders of the carapace, is 15 inches. The length of the shell, or of
the carapace, in a straight line is estimated to have been about a foot and a

172

half. The length of" the plastron is estimated to have been about 14 inches;
its breadth at the root of the posterior extremity is 5^ inches; and at the root
of the anterior extremity has been rather less. The sternal bridges measure
7 inches fore and aft, and their length to the outer edge of the carapace is 5
inches.

Other measurements of the shell are as follows :

Inches.

Length of second vertebral scute area, estimated at 4 J

Breadth of second vertebral scute area 3^

Length of third vertebral scute area 4J

Breadth of third vertebral scute area 3i

Length of fourth vertebral scute area Si

Breadth of fourth vertebral scute area 3i

Breadth of second costal scute area, internally 4|

Breadth of second costal scute area, externally 4J

Breadth of third costal scute area, internally 3§

Breadth of third costal scute area, externally 3^

Height of sixth and seventh marginal scute areas 2.J

Length of hyposternals internally 5

Breadth of hyposternals internally 5^

Breadth of hyosternals Sf

Breadth of plate intercalated between the hyosternals and hyposternals G

Extent of the same plate at the base externally, fore and aft 4f

Breadth of groove between pectoral and abdominal areas where it joins the pro-
jecting angle of the third sterno-costal scute areas 7J

Breadth of plastron at anterior suture of xiphisternals 4i

Breadth of pectoral scutes to sterno-costal scutes 4 and 4^

Length of abdominal scute internally 3

Length of femoral scute internally 3^

Axillary scute area, length at middle 1^

Axillary scute area, breadth at middle 2i

First submarginal scute area, length at middle . . 2i

First submarginal scute area, breadth at middle. . 2^

Second submarginal scute area, length at middle 2

Second submarginal scute area, breadth at middle - 2a

Inguinal scute area, length at middle 2f

Inguinal scute area, breadth at middle 2^

The sacral vertebrae, represented in Figs. 11, 12, Plate XIX, are of pro-
portionately greater length than in Baena. The first one is nearly as long as
it is broad ; and the second is half as long again as the former, and is equal
ill this respect to its breadth.

The anterior articulation of the first sacral centrum forms a decided cup-
like depression, and not merely a transverse concavity like that in the snap-
per. The second sacral centrum is prolonged to an unusual degree beyond

17^

the neural arch. It ends iu a flat, roughened articular surface, as if iulendrd
for tlie conjunction of another vertebra entering into the constitution of llu;
sacrum. The neural arches of the sacral vertebrie are proportionately higher
than in the snapper, and they appear to have articulated movably with each
other by zygapophyses alone.

The diapophyses are about equally developed with those in the snapper.
The neural arch is not co-ossified with the centrum ; nor are the pleurapophyses
co-ossified with either.

Measurements of the sacral vertebaa are as follows :

Liues.

Length of the sacrum inferiorly 18

Length of first sacral centrum 7

Breadth of first sacral vertebra, with diapophyses 9

Length -of second sacral centrum 11

Breadth of secoud sacral vertebra, witli diapophyses 10^

Height of first sacral vertebra to end of spinous process 13

Height of anterior articulation of first sacral centrum ■. 5

Breadth of anterior articulation of first sacral centrum 5

An isolated vertebra, from Henry's Fork of Green River, looks as if it
might be the first sacral of Chisternon undatum. The body is little more than
half the length of that of the last sacral above described, but its anterior
articular surface agrees in size, form, and roughness with the posterior sur-
face of the last sacral centrum just mentioned. .The pleurapophyses have
about the same degree of develo])ment as in the snapper.

Fig. 10, Plate XVI, represents a caudal vertebra, obtained by Dr. Carter
near Lodge-Pole Trail. In construction it resembles the caudals of the
snapper, the centrum, as in this, lieing opisthocoelian, or having a cup behind
and a ball in front. The proportions of the vertebra accord best with the
more anterior caudals of the snapper, but its transverse processes are as small
as in the terminal, caudals of the latter. Perhaps it may belong to Chister-
non, but the opinion is conjectural. If the former isolated vertebra belongs
to Chisternon, it is doubtful whether this second one does.

Fig. 7, Plate XVI, represents an isolated ilium of a turtle, found at Grizzly
Buttes by Dr. Carter. It resembles in its form that of a snapper, but is more
robust in proportion to its length. The inner surface at the up])er extremity
is flat and longitudinally striated, but is devoid of the fossa existing in the
.snapper. The length of the bone is 3^ inches; the width of its upper end
!| of an inch ; the width at the lower end is 17 liues. From the form ol'llie

174

bone I would suspect that it belonged to Chisternon, rather than to either
Emys Carteri or Baptemys wyomingensis.

HYBEMYS.

Hybemys akenarius.

Two Httle specimens, obtained by Professor Hayden, in the Tertiary for-
mation of Little Sandy Creek, Wyoming, appear to indicate a previously
undescribed turtle, to which the above name was given. They consist of

a detached marginal bone, and a fragment of a costal plate of a species
about the size of the common spotted turtle, Emys guttata. The bones are
unusually thick in proportion to their breadth, compared with those of ordi-
nary recent Emydes. Their surface is smooth and strongly marked by the
lines of separation of the scute areas. The costal ridge on the interior of the
costal plate is scarcely perceptible ; the costal capitulum is rather stouter
than in Emydes.

The marginal plate represented in Fig. 9, Plate XV, is especially remark-
able, and it is upon its peculiarity that the genus is inferred. It would appear
to correspond with the ninth of the series, and has the same form as in the
corresponding plate of ordinary Emydes. The outer portion of the upper
surface, strongly defined by the groove of the costal scute, exhibits at its fore
and back part a half-circular boss, occupying the middle of the marginal
scute areas. As we may safely infer the other marginals to have the same
construction, it follows that the margin of the carapace is ornamented with a
circle of hemispherical bosses, each of which is crossed by the sutures of the
marginal bones.

ANOSTEIRA.

Anosteira oenata.

Among the many remains of turtles from the Bridger Tertiary formation,
submitted to my examination from time to time, by Dr. Carter and Professor
Hayden, there were a few isolated plates of peculiar character which were
described and referred to a genus and species under the above name. Sub-
sequently Dr. Carter discovered many parts of a shell of the same species,
which we have endeavored to collocate as represented in Figs. 1, 2, Plate
XVI.

Anosteira is a remarkable genus, very unlike any other turtle, 'previously

175

described, recent or extinct. The carapace and plastron, while being com-
pletely ossified as in Testudines, Eniydes, &c., are ornamented in a manner
only seen to the same degree in the soft-shelled turtles. True, we see some-
thing like ornamentation of the same kind in some of the Emydes,.but in
them the condition is comparatively feeble. The osseous shell also appears
to be devoid of the usual outlines more or less sti'ongly expressed of the in-
vesting scutes. A few of the plates exhibit obscure lines, but I am uncertain
as to whether they accord with the areas of the scutes.

The outline of the carapace is broadly cordiform and somewhat resembles
that of the ordinary sea-turtles, but is not acute posteriorly as in these, being
obtuse as in the Bmydes. The prominence of the carapace is moderate as in
the less elevated forms of the latter. It is uniformly convex, except that it
is acutely carinated in the median line posteriorly.

The margin of the carapace anteriorly is rather obtuse, but laterally and
posteriorly is quite sharp. It is broadly and concavely notched in front ; the
first pair of marginal plates being the most prominent portions anteriorly.
Antero-laterally it is slightly concave, and from this position posteriorly is
uniformly convex.

The plastron with its bridges is flat, and is intermediate in its relative pro-
portions with that of the snappers and Emydes. The bridges articulate with
the carapace by gomphosis, as seen in Fig. 2. They join the marginal plates
from the fifth to the eighth inclusive. The extremities of the plastron are
botli broken away in the specimen.

The vertebral plates of the carapace are narrow coffin-shaped. Those an-
terior are nearly level ; those posterior are acutely carinated.

The costal plates within exhibit no costal elevation, but are quite level, as
represented in Fig. 3. The costal capitula are unusually broad but thin.

The inner surface of the nuchal plate at the posterior border presents a
pair of round articular processes for conjunction with the contiguous vertebra.

The upper surface of the carapace is ornate with rugosities. These are
obsolete on the vertebral plates. On the costal plates they appear as longi-
tudinal, undulating, and nearly parallel ridges crossing the plates. Internally
they are feebly developed and become more strongly marked proceeding out-
wardly.

On the marginal, including the nuchal and pygal plates, the rugosities arc
finer, closer, more interrupted, and in part even granular.

17G

Beneatli, the rugosities of the marginal plates have a decidedly radiant
appearance. The under surface of the marginals in advance of the axillary
notches, and the corresponding surface of the nuchal plate, are smooth or de-
void of the ornate rugosities.

The pygal plate and the contiguous marginals increase in thickness from
their free acute edge inwardly, so as to be wedge-shaped in section. The
base of the wedge, directed toward the cavity of the shell, is strongly grooved
in the pygal plate, and gradually less so in the contiguous marginal plates.
The groove contributes to the general cavity of the shell. Fig. 6 represents
a fore and aft section of the pygal plate, exhibiting the groove on its inner part.

The plates of the plastron exhibit their ornate ridges arranged in a radiat-
ing manner, as seen in Fig. 2, but they are less prominent than those of the
carapace.

The shell of the specimen of Anosteira, from which the above description
was taken, in its entire condition, was about 5 inches in length in the median
line and about 4^ inches in breadth.

Figs. 4, 5, represent two anterior marginal [)lates, showing that the species
reaches a much greater size.

TRIONYX.

Trionyx guttatus.

One or more species of the soft-shelled turtles ( Trionyx) are indicated by
an abundance of fragments of shells which have come under my notice in the
various collections of fossils from the Bridger beds. Anything like complete
shells appear to be rare, as the best preserved which has yet been submitted
to my examination is the portion of a carapace i-epresented in Fig. 1, Plate
IX. The specimen, attached to a mass of sandstone, was obtained at Church
Buttes, near Fort Bridger, during Professor Hayden's exploration of 1868

The osseous carapace in its entire condition is estimated to have been
about a foot and a quarter in length, and, independently of the extension of
the free ends of the riljs, has nearly reached that breadth. The bones range
from three to four lines in thickness, except along the position of the costal
ridges and near the thinner edges.

The carapace appears to iiave had the usual composition of seven vertebral
plates, and eight pairs of costal plates back of the nuchal plate. It was mod- ■
erately convex, and the posterior border in the specimen is deeply scolloped.

177

The vertebral plates in the specimen, consisting of part of the second, tliini,
and itmrtli, are reversed coffin-shaped, and nearly twice as long as wide.
Their anterior border is convex, and the posterior border concave.

The fifth vertebral plate is smaller than the preceding, and becomes eaiTier
narrowed from the sides toward the back end.

The sixth plate is lozenge-shaped, about as long as it is wide, and occupies
the space between the truncated angles of the sixth and seventh costal plates.
The latter meet in the median line for more than half their width.

The seventh vertebral plate is a very small lozenge-shaped bone, with a
crucial ridge on its surface, occupying an interval produced by the truncation
of the contiguous angles of the seventh and eighth pairs of costal plates.

The costal plates, from the fourth to the sixth inclusive, are nearly of the
same width internally, and they successively become more widened out-
wardly. The seventh costal plate is rather wider at the extremities tlian
intermediately. The last costal plates are nearly as wide fore and aft as from
within outwardly.

The surface of the carapace is sculptured tor the most part with broad,
rounded, and isolated concave pits resembling the impression of rain-drops on
a soft surface. Only near the outer border of the costal plates, where these
are preserved, do the pits become more or less confluent, usually in twos and
threes. The reticular ridges bounding the pits are broad and low, and often
as wide as the included pits.

Measurements of the specimen are as follows :

Lines.

Length of tliird vertebral plate . . 23

Width of third vei'tebral plate iu front 7

Width of third vertebral plate behind 12

Length of fourth vertebral ijlate 20J

Width of fourth vertebral plate in front 7^

Width of fourth vertebral plate behind 10;^

Length of fifth vertebral plate , I'Ji

Width of fifth vertebral plate in front 7

Width of iifth vertebral plate at middle Sft

Length of sixth vertebral plate - 10

Width of sixth vertebral plate at anterior third 10

Length of seventh vertebral plate 5|

Width of seventh vertebral plate at middle 5

Width of fourth costal plate fore and aft at inner part 23

Width of fifth costal plate fore and aft at inner part 22

Width of sixth co.stal plate fore and aft at inner part 21

Width of seventh costal plate fore and aft at inner part IDJ

23 G

178

Liucs.

Width of eighth costal plate fore and aft at inner part ... 18

Length of sixth costal plate at middle 58

Length of seventh costal plate at middle ... 41

Length of eighth costal plate at middle 22

Many fragments, l)oth of the carapace and plastron of soft-shelled turtles,
collected during Professor Hayden's expedition of 1870, and subsequently
bj' Drs. Carter and Corson at various localities in the vicinity of Fort Bridger,
appear to be referable to the same species as the above.

A specimen consisting of the right half of a nuchal plate, with an attached
piece of a first costal, derived from the same locality as the specimen above
described, belonged to an animal about the same size. The width of the
scabrous portion of the nuchal plate in its complete condition was about 6f
inches; its fore and aft extent 1^ inches. The sculpturing of the surface is
more interrupted or broken than in the specimen specially referred to Trionyx
guttatus. The reticular ridges ^.re narrower and sharper, and exhil)it a dis-
position to rise in points at their intersection.

A specimen consisting of an outer portion of an intermediate costal plate
measures 3f inches wide, and is 5 lines thick. The reticulation of its sur-
liicc is unbroken, but otherwise it reseml)les that of the nuchal plate just
described.

Teionyx uintaensis.

During my stay at Fort Bridger, in a trip to Dry Creek, Major R. S.
La Motte discovered the nearly complete carapace of a Trionyx, which he
presented to the Academy of Natural Sciences of Philadelphia. The sjieci-
men is represented in Fig. 1, Plate XXIX, one-half the natural size. On first
view I supposed it to belong to the same species as the former, but compar-
ison of the specimen with that of Fig. 1 of Plate IV leads to the belief that
it pertains to a different one.

The carapace is about 16J inches long and 16 inches broad, so that its
proportions are reversed from those in our living Trionyx muticus. It is
about as convex as in the latter, and appears to have been slightly depressed
along the position of the vertebral plates, judging from that portion of the
shell back of the fiith costal plates, as in advance of this the specimen has •
been crushed inwardly. The fore and back part of the carapace is truncated,
as in T. miiflcys. The posterior truncation, slightly sinuous, extends the
width of the last two pairs of costal plates. In T. gtittalus the corresponding

179

border occupied 1)} the latter is convex, and exliibits three deep .siiuiosilies —
the middle one and the one on each side, as seen in Fig. 1, Plate IX.

Eiglit })airs of costal plates succeed the nuchal plate. The second, fifth,
and sixth pairs expand considerably outward, more especially the last of
these. The others are of more uniform breadth.

The specimen possesses only six vertebral plates. Of these, the first is the
longest and widest. Its fore border is convex, and nearly in a line with the
suture between the nuchal and first pair of costal plates. The lateral borders
diverge to the back angles, -which are truncated to join the second pair of
costal plates.

- The' second and third vertebral plates are nearly equal in size, and are
reversed coffin-shaped. The fourth plate is smaller, and oblong (pmdrate,
with convex borders. The fifth plate is obverse coffin-shaped, shorter, but
wider than the former. "^Fhe sixth vertebral plate has not more than half its
usual development. It is pentagonal shield-like, and is included between the
angles of the fifth and sixth costal plates.

The posterior half of the sixth costal plates, and those succeeding them,
unite in the median line by a tortuous suture.

The surface of the carapace presents a nearly uniform reticular aspect
and the thickness of the bones is of the usual proportion.

The measurements of the specimen are as follows :

Space occupied by the six vertebral plates

Breadth of uucljal plate

Extent of uuclial plate in median line

Breadth together of seventh pair of costal plates
Breadth together of eighth pair of costal plates .

Inches.

Breadth.

First vertebi'al plate . . .
Secoud vertebral plate .
■ Third vertebral plate . .
Fourth vertebral plate
Fifth vertebral plate . . .
Sixth vertebral plate . . .

180

Leugtli.

Depth
iutcrnally.

Depth
externally.

First costal plate . .
Sceoiul costal i)late-
TLird costal plate . .
Foiirtli costal [)late.
Fifth costal plate . . .
Sixth costal plate . . .
Seveuth costal plate

I Itches.
G
8
8

8
8

Lines.

29
22
21
23

18
16

Lines.
32
38
26
26
33
42
21

REMAINS OF TRIONYX OF UNDETERMINED SPECIES.

Small tVagineuts of Trioiiyx shells, from the Bridger Tertiary strata, exhib-
iting a ditrereiit kind of surface-marking or sculpture from that of the specimens
referred to the preceding species, probably indicate others, or, perhaps, differ-
ent genera. .

A specimen found l>y Dr. Carter at Dry Creek, and represented in Fig. 11,
Plate XVI, is an outer fragment of a costal plate. It is not pitted as in
Tronyx guttatus, but is crossed obliquely by coarse ridges with the intervals
occupied by a lattice of narrower ridges. Probably the specimen may belong
to a species of Anosteira.

Another fragment of a costal plate, from Little Sandy Creek, is represented
in Fig. 12 of the same plate. This specimen differs from the former in being
crossed by widely separated ridges, with the intervals finely pitted.

Other specimens exhibit slight differences from the foregoing and from
those of Trionyx gutlatus, but are too imperfect to enable one to form any
idea of their relationship.

• Order Lacertilia.

The lizards have vertebrae with concavo-convex bodies, and have the teeth
co-ossified with the jaws. The skin is furnished with horny or bony scales.
True lizards, allied to the existing monitors, iguanas, and chameleons, appear
to have been abundant and of varied character in the ancient Wyoming fauna.
Few remains of these animals, described in the succeeding pages, have been
submitted to my inspection, but Professor Marsh has indicated and briefly
described twenty-one species- of five extinct genera from fossils obtained
by him from the Bridger beds.

181

SANIVA.

Saniva ensidens.

An extinct lizard, to whicli the above name has l)cen applied, is indicated
by some remains discovered during Professor Ilaydcn's exploration of 1870,
near Granger, Wyoming. The remains consist of portions of a skeleton, in a
fragmentary condition, imbedded in an indurated ash-colored marl rock. The
bones are black, and the hollows of the long Ijones, including the ribs and
phalanges, are occupied with crystalline calcite.

The remains belong to a lacertian about the size of the existing monitor
of the Nile, to which it appears to have been closely related. The bones
indicate a robust body, a long tail, and limbs with long toes.

The vertebrae resemble those of the Nilotic monitor in form and propor-
tions, and like them possess no zygosphenal articulation.

A pair of dorsal vertebrae are represented in Fig. 15, Plate XV. Tlie body
is J an inch long inferiorly, and measures f of an inch l^etween the dia-
pophyses. The ball and socket extremities are twice the breadth of the height.
The ball measures 4 lines in breadth and 2 lines in height. The neural arch
laterally at the zygapophyses is nearly 8 lines long.

An anterior caudal has the same length as the dorsals, but is narrower.
The ball is of less width, but the same height. The hypopophyses for the
chevron are quite prominent, and are situated a short distance in advance of
the ball, as in the monitor.

A small detached tooth, imbedded in the same mass, in proximity to some
small skull-fragments, presents the form and constitution of those of the moni-
tors. It is represented in Fig. 35, Plate XXVII, magnified eight diameters.
The length of the tooth is about IJ lines; its breadth, f of a line; and its
thickness, J a line. It is compressed conical, feebly curved niwardly and back-
ward, sharp-pointed, has abruptly impressed trenchant borders, and is smooth
and shining. It is hollow, and has thick walls. The transverse section of
the base is rhomboidally oval, with acute poles.

In breaking off portions of the rock containing the bones aljove described,
there was exposed what appears to be the anterior extremity of a maxillary
containing the remains of six teeth. The fragment is 4 lines long and 1^-
lines deep. The teeth are pleurodont in character, but appear different in
ibrm from tlie isolated tooth above indicated, and have more resemblance in
shape to those of the iguana. The specimen appears so small in ils propor-

182

tions with the other bones, that it leads to the suspicion that it may not belong
to the same skeleton.

No scales were ibund in association with the bones in the same mass of
rock.

The name Saniwa, according to Professor Hayden, is nsed by one of the
Indian tribes of the Upper Missonri for a rock-lizard-.

Saniva major.

Several fragments, discovered by Dr. Carter near the Lodge-Pole Trail,
crossin'g Dry Creek, would appear to indicate a larger species of Saniva. The
specimens are of a greenish hue and somewhat smooth or water-worn, and
were derived from a green sandstone stratum.

One of the fossils consists of the distal extremity of a humerus, repre-
sented in Fig. 14, Plate XV. It resembles in general aspect the correspond-
ing portion of the humerus of the monitor, but the shaft is proportionately
more robust, and not so much narrowed toward the middle. It is occupied
by a large medullary cavity with compact walls, as in the humerus of a bird.
The internal epicondyle appears less prominent than in the monitor, in con-
sequence of the less degree of contraction of the shaft. The external epicon-
dyle does not reach upward to more than half the relative extent it does in
the monitor, and it is not perforated. The ulnar eminence is prominent in
front, but projects below to a less degree than the radial capitellum.

The breadth of the bone at the epicondyles is f of an inch. The greater
diameter or breadth of the shaft at the broken end is 3| lines ; the short
diameter is 2^ lines.

Another of the fossils consists of a pair of dorsal vertebras, represented in
Figs. 36, 37, Plate XXVII. They agree in all respects with the two vertebrae
referred to the former species, except that they are considerably larger.

The bodies of the vertebrae inferiorly measure 7| lines in length and lOi
lines in width between the diapophyses. The ball measures 5 lines in In-eadth
and 3 hnes in height. The neural arch laterally at the zygapophyses is 10
lines in length

GLYPTOSAURUS.

Professor Marsh has described, in the American Journal of Science and
Arts for 1871, another genus of extinct lizards, under the above name, from
remains obtained in the liridger Tertiary. He observes that "the head was

183

covered willi large osseous shields symmetrically iirniiigcd and highly orna-
mented. Other i)ai-ts of the body, especially the ventral region, were pi-o-
tected by rectangular, ornamented shields, united to each other Ijy suture.
The teeth are pleurodont, and are round with obtuse summits. The dorsal
and caudal vertebra? have the same general form as those of Varauus, but show
traces of a zygospheue articulation.

Professor Marsh indicates eight species, maiidy liiunded on diii'erences in
the position, form, and ornamentation of the dermal osseous shields and the
form of the teeth.

Dr. Carter has submitted to my examination a number of specimens col-
lected by him at Grizzly Buttes, which in part or whole are attributable to
the same genus, and mostly to the species named Glijptosaurus ocellatus.

Several of the dermal shields from the trunk of the body are represented
in Figs. 13 to 15, Plate XVI, and several of the cranial shields in Figs. 16, 17,
of the same plate, all magnified two diameters.

The dermal shields of the trunk are oblong cpiadrate, with the longer mar-
gins thick and roughened for sutural conjunction with one another. The ex-
tremities thin out for imbrication. The anterior exti-emity, which is over-
lapped by the shield in advance, extends a third or more of the length of the
plate, and is smooth. The posterior two-thirds or less of the shields are orna-
mented on their free surface with nnnided knobs or tubercles, closely arranged
in more or less concentric rows.

The cranial shields are from foui- to six sided, and proi)ortionately of greater
thickness than the former. All their margins are roughened for sutural at-
tachment together, and their free surface is ornamented in the same manner
as the shields of the trunk.

Accompanying the specimens of dermal shields above described, there are
several detached vertebrae. One of the specimens is a dorsal vertebra re-
sembling those of Saniva, but somewhat smaller, and, like them, presents no
zygosphene articulation. It may probably belong to that genus. The other
specimen is an intermediate caudal vertebra of the same proportions of length
and breadth as in Saniva, but the ball and socket articulation is as high as it
is wide. It has no zygophene articulation, and the hypopophyses for the
chevron are immediately beneath the ball of the body. The length of the
latter interiorly is 2| lines. -

184

CHAMELEO.

Chameleo peistinus.

A small fragment of a lower jaw with teeth, discovered by Dr. Carter in
the Bridger Tertiary formation, is represented in Figs. 38, 39, Plate XXVII,
magnified three diameters. In every respect it agrees with the correspond-
ing part of tlie jaw of tlie living chameleons, but^ indicates a much larger
species. In a space of 5 lines the alveolar border is occupied by eight teeth
successively increasing in size from Ijefore backward.

The teeth are laterally compressed conical, with the borders in front and
behind somewhat extended and acute, and at the base produced into a minute
denticle. Externally the bases of the teeth are separated by perpendicular
furrows descending on the face of the jaw to the position of a finely perforate
horizontal line. Beneath the bases of the teeth internally there is a wider
and more conspicuous horizontal and perforated groove. Below this, toward
the rounded base of the jaw, the usual Meckelian groove is situated. The
outer face of the jaw exhibits two vasculo-neural foramina. The depth of
the lower jaw from the point of the last tooth of the specimen is 2 J lines.

FISHES.

The remains of fishes in the Bridger beds are not so abundant as one might
have supposed from the nature of their composition and the conditions of their
origin. Nevertheless, it is probable that fishes were abundant in genera,
species, and individuals in the great Uintah Lake and its tributaries, whose de-
posits form the Bridger beds. The same circumstances which removed the
less coherent parts of the skeleton from the interior of the many turtles, and
likewise scattered the bones of these and of the multitude of other reptiles
and of mammals, no doubt served to destroy the more delicate strncture of
the fishes and to distribute their hard parts through the mud. It is probable
that future explorations may lead to the discovery of some strata of the Bridger
beds in which well-preserved forms of fishes may exist like those found in the
shales of the deeper beds of Green River.

The remains of fishes from the Bridger beds, which, with few exceptions,
were found by Dr. Carter and submitted to my examination, consist mainly of
smoothly enameled ganoid scales, a few isolated specimens of vertebral centra,
portions of spinous raj^s, and fragments of jaws with tcetli. My means of
comparison of these specimens with the skeletons of recent fishes are ex-

185

ceediiigly meager, but they indicate forms wliich generally appear to he most
nearly related with our mud-tishes, (^Aniia,) and the gars, {Lepidosteus,)

Professor Marsh (Proceedings of the Academy of Natural Sciences of
Philadelphia, 1871, p. 105) has already noticed specimens from the same
locality, which he refers to two species of Amia about the size of A. calva,
and two species of Lepidosteus about the same .size as the modern gar-pike.

AMIA.

Amia (Peotamia) uintaensis.

A number of specimens, discovered by Dr. Carter on the l:)uttes about ten
miles from Dry Creek Canon, indicate a large fish related with the modern
Amia, but exhibiting sufficient peculiarity to pertain to a different genus, for
which the name of Protamia has been proposed.

Figs. 1, 2, Plate XXXII, represent one of the best-preserved specimens, a
vertebral centrum from the fore part of the dorsal series. Its breadth is con-
siderably gi-eater in proportion with its length than in Amia;' it is more
prominent below ; has a different transverse outline; has shorter parapophyses,
which also spring from a higher position at the sides, and the bottom of the
articular cones is situated considerably above the centre.

The centrum is nearly tour times the width and three times the height of
its length. It is slightly curved from side to side with the convexity directed
forward. It is widest at the upper third, opposite the origin of the para-
pophyses, and is shortest at the sides intermediately.

The articular cones have their bottom considerably above the center, and
are more minutely perforate for the notochord than in Amia.

The sides of the centrum are concave between the pi'ominent articular
margins, and slant in a nearly straight line to the ridges defining the narrow
inferior surface. The latter is concave, and the lateral ridges are obtuse, and
excavated in an oblong shallow fossa at their fore part.

The upper part of the centrum is transversely convex between the jtara-
pophyses. The articular fossas for the contiguous neural arches, as in Amia,
are in the form of the figure of 8, and their internal prominent borders form
the lateral limits of the bottom of the neural canal.

The parapophyses are short, stout processes projecting above the middle
of the centrum from its widest part, and on a line with the bottom ol tlic
articular cones.
24 G

186
The measurements of the specimen are as follows:

Liues.

Lcngtli of ceuti'um iiifeiioily 5. C

Height of ceutrum auteriorly 15. 5

Width of centrum iu line with the parapophyses 20. 0

Another specimen from the same locality as the preceding is represented
in Figs. 3, 4, Plate XXXII. It appears to be the centrum of an atlas, and
may probably belong to the same species as the former, though, judging from
its difterent aspect, to a ditfereut individual.

The centrum is transversely oval and slightly curved, with the convexity
of the curve directed forward Its breadth is two and a half times the height,
and over live times the length.

The anterior sui-face is nearly flat and somewhat uneven, and just above
the center is depressed into a concave pit about one-fifth the diameter of the
centrum. The posterior surface presents the usual cone with its l)ot-
tom just above the center.

The sides of the centrum are concave between the articular borders, and
bear no trace of parapophyses. The lower part is more flat, and presents a
shallow fossa on each side of a median concavity. The fossae for the neural
arch are quite prominent at their contiguous borders.

The measurements of the specimen are as follows :

Lines.

Length of centrum inferiorly 4

Height of centrum anteriorly 14

Breadth of ceutrum at middle 22

A third specimen, from the same locality, less well preserved, resembles
the first one, and belonged apparently to a somewhat smaller individual. Its
parapophyses barely project beyond the sides, and are hollowed at the end.
The ridges defining the inferior surface from the concave sides are barely
excavated.

Its measurements are as follows :

Lines.

Length of centrum inferiorly 5. 5

Height of centrum auteriorly 15. 5

Breadth of ceutrum at the upper third 18. 25

A series of three specimens, witii a portion of another, from the same
locality as the preceding, appear to correspond with the anterior vertebrae of
Araia from the second to the fifth inclusive. The fragment resembles the
lateral half of the atlas above described, but is bi-concave. The other speci-
mens resemble the first and third ones above descril)e(l in the form of the

187

centrum. In 'the third vertebra the parapopliyses arc higli up, as in the iirst-
described specimen. In the succeeding two they spring Ironi near the middle
of the sides of the centrum.

The measurements of the second cervical are as follows :

LineB-

Length of centrum inferiorly 4

Depth of centrum anteriorly i;j

Breadth of centrum at middle 20

. The measurements of the fifth vertebra are as follows :

Lines.

Length of centrum inferiorly 3. 6

Depth of centrum anteriorly . 12. 0

Breadth of centrum at middle, ou line with parapophyaes 17. 0

A series of three posterior dorsal centra, from the same locality as the
preceding specimens, perhaps belong to the same species, but, from their
appearance, most probably to another individual. They are somewhat dis-
torted from pressure, and appear in the original condition closely to have
resembled corresponding vertebrae of Amia^calva, but are nearly three times
the breadth, and scarcely twice the length.

The three specimens together, represented in Fig. 5, measure 16 lines in
length.

The anterior of the three presents the following measurements :

Lines.

Length of centrum inferiorly 5

Depth of centrum anteriorly 11

Breadth of centrum inferiorly, opposite the diapophyses 14

A specimen from Dry Creek, consisting of a mutilated basi-occipital, about
the size of that of the alHgator-gar, ditfers considerably as well as from that
of the mud-fish. It is represented in Figs. 6, 6", and may perhaps belong to
Protamia.

The articular conical cup has its acute margin scolloped, as seen in Fig. 6.
The deep median groove on the under part of the bone in Amia and Lepi-
dosteus reaches the articular margin, but in the fossil, stops the fourth of an
inch short of it. On each side of the bone at the articular margin correspontiing
with the lateral notch there is a conspicuous fossa not seen in the genera just
named. In advance of the fossa on each side of the median groove there is
a broad, slanting, flat surface, longitudinally ridged, of which there is likewise
no exact counterpart in Lepidosteus, but appears to correspond with a smooth
surface occupying the same position in Amia.

188

Amia (Peotamia) media. •

Figs. 7 to 9 represent a vertebral centrum, obtained at the junction of the
Sandy and Grreen Rivers, during Professor Hayden's expedition of 1870. In
its form and proportions it resemJiles a centrum from near the fore part of
the dorsal series of Amia calva, but pertainetl to a species double the size.
It presents several peculiarities which render it probable that it belongs to a
related genus. The sides of the centrum ai-e less contracted than in Amia,
and the pair of ridges beneath are substituted by a pair of oval pits. The
parapophyses project transversely just above the middle, and are very short.

The measurements of the specimen are as follows:

Lines.

Leugtb of ceutrum inferiorly 5. 5

Height of centrum 10. 2

Breadth of centrum 1.3. 0

Figs. 10, 11 represent a vertebral centrum, found by Dr. Carter on Dry
Creek. It resembles a centrum of Amia calva from the back of the dorsal
series, but is double the size. It presents beneath a pair of grooved ridges,
as in A. calva.

The specimen measures as follows :

Lines.

Length of centrum inferioi'ly 4. 0

Height of centrum 7. G

Breadth of centrum 8. 6

Amia (Protamia) gracilis.

Figs. 23, 24, Plate XXXII, represent a vertebral centrum found by Dr.
Cai'ter, together with a number of ganoid scales, opposite the second cross-
ing of Henry's Fork of Green River. The centrum has a different color from
the scales, and clearly did not belong to the same fish. It is from near the
middle of the dorsal series, and pertained to a smaller species than Amia
calva The two ridges beneath the centra of the latter are substituted by
^two oblong fossae.

The measurements of the specimen are as follows:

Lines.

Length of vertebral centrum inferiorly 1. 8

Height of vertebral centrum 3. -t

Breadth of vertebral centrum 3. 8

189

HYPAMIA.

Hypamia elegans.

Figs. 19 to 22, Plate XXXII, represent a vertebral centrum, found hy Dr.
Carter on Dry Creek. It is from near the middle of the dorsal series, and
evidently indicates a genus distinct from but nearly related with Amia. As
in this, the cenlrum is short in proportion with its breadth, and it presents
sutural impressions for a contiguous pair of neural arches. The articular
cups have their bottom central and minutely perforate. The sides below the
parapophyses are concave, and converge to a median prominence, which is
excavated into a pair of fossas, separated only by a linear partition. The
l)arapopliyses ai'e cylindroid and comparatively short.

The measurements of the specimen are as follows :

Lines.

Length of centrum iuferiorly 2. li

Depth of centrum anteriorly (i. 5

Breadth of centrum anteriorly 7. (5

Breadth of centrum, including parapophyses 8. 5

The specimen indicates a species about one-third larger than Amia calva.

LEPIDOSTEUS.
Lepidosteus ateox.

During Professor Hayden's expedition of 1870, James Stevenson collected
a number of remains of tishesat the junction of Big Sandy and Green Rivers,
Wyoming. The specimens consist of isolated vertebral centra, ganoid scales,
and portions of jaws with teeth, all of a black hue. Among them are several
vertebrae indicating an extinct species of gar larger than the existing alliga-
tor-gar, Lepidosteus ferox.

Figs. 14, 15, Plate XXXII, represent the centrum of a vertebra from a
position in advance of the middle of the dorsal series. The length of the
centrum is not greater than the breadth. The extremities are hexaliedral in
outline. The under surface is flat, and ornate with longitudinal and somewhat
reticular wrinkles. The sides beneath the pai-apophyses are impressed into
a deep fossa. The neurapophyses are likewise impressed at the sides with a
deep fossn, and a second deep pit occupies a position just behind and above
tlu! parapophyses. These appear rather narrower than in the alligator-gar,
atnl are less anterior in [tosition.

190
The measurements of the specimen are as follows :

Lines.

Length of centrum iuferiorly . . 8. 6

Breadth of ceutrum posteriorly 8. G

Height of ceutrum i)osteriorly — , CO

Another specunen, consisting of a caudal centrum, perhaps belongs to the
same species. It has about the same length as the preceding, and is hexa-
gonal in outline at the ends. Its sides present a strong longitudinal ridge
separating a deep fossa below from another above.

The measurements of the specimen are as follows :

Lines.

Length of centrum interiorly 8. 4

Breadth of centrum posteriorly 4. 4

Height of centrum ijosteriorly 4. 8

Lepidosteus ?

Accompanying the preceding specimens there are two vertebrae of another
species of Lepidosteus. One of them is a posterior dorsal centrum, and is
represented in Figs. IG, 17. It is about as long as the corresponding centra
of the gar-pike, Lepidosteus osseus, but is ^jroportionately broader and more
robust. Its articular ends are hexahedral, with the upper and lower borders
slightly emarginate. The lower surface of the centrum is nearly flat, nearly
level, contracted at its anterior third, and deeply grooved along the middle.
It is bounded by ridges defining it? from the deeply impressed sides.

The other specimen is the centrum of a caudal nearly as long as the former,
but narrower in proportion with its difference of position in the series.

The measurements of the specimens are as follows :

Lines.

Length of dorsal centrum iuferiorly 5. 4

Length of caudal centrum iuferiorly , 5. 0

Breadth of dorsal centrum posteriorly 5.4

Breadth of caudal centrum posteriorly 3. 0

Height of dorsal centrum posteriorly 4.2

Height of caudal centrum posteriorly 3. 2

These specimens may, perhaps, belong to one of the species indicated by
Professor Marsh.

Figs. 27 to 30 represent several ganoid scales, accompanying the preceding
specimens, which probably pertain to the smaller of the two Lepidostei.
They are covered \\itli perfectly smooth, shining ganoine without markings.

Fig. 25 represents a fragment of the fore part of the right ramus of the
lower jaw accompanying the former specimens. Its construction is similar

191

to the corresponding part in the alligator-gar, but is proportionately not so
tliick or rolnist near the sympiiysial end. The lower surface is reticulated
with round meshes, and the ridges of the net are ornate with shining trans-
lucent tubercles.

The dental groove exhibits the remains of a row of large teeth, of which
one retained exhibits the same cliaracter as those of the living gars. The
outer edge of the groove was also furnished with minute teeth, but the inner
edge exhibits no trace of these organs.

Lepidosteus simplex.

Some remains of a Lepidosteus, together with some fragments of a turtle-
shell, were collected near Washakie Station, Wyoming, by James Stevenson,
during Professor Hayden's exi^loration of 1870. The remains of the Lepidos-
teus consist of a mutilated basi-occipital and three succeeding vertebral cen-
tra, together with several small jaw-fragments and a number of large ganoid
scales.

The basi-occipital and vertebral centra, represented in Fig. 18, Plate
XXXII, resemble in form and proportions those of alligator-gar, but an;
smaller.

A tooth, represented in Fig. 26, contained in one of the jaw-fragments
agrees in character with the larger teeth of living gars. The outer edge of
the same jaw-fragment is furnished with smaller and more curved teeth of
the same kind.

Figs. 31, 32 represent two lozenge-shaped scales of less In'cadth but thicker
than those of the alligator-gar. The enamel surface is flat, smooth, and
highly polished, and exhibits no markings except one or several minute puncta
near the center.

Fig. 33 represents a similar scale, which appears to be traversed lijre and
aft by a canal communicating by a sliort cleft with the outer surface. The
cleft is directed backward, and is protected by an angular elevation of the
anterior border.

Fig. 34 represents another scale of a different form, probal)!y from I he
median line of the back.

The measurements of the basi-occipital and vcrteljral centra are as follows :

Liues.

Breadth of the articulation of the basi-occipital 10. 0

Height irom lower groove to ed^e of occipital foi'amen "). 0

Length of first vertebral ceutriiui -1. 0

192

Lines.

Breadth of first vertebral centrum 10. 0

LcDgtli of secoud vertebral ceutrum 4. 4

Breadth of secoud vertebral centrum 7. 6

Length of third vertebral centrum 5. 0

Breadth of third vertebral ceutrum 6. 8

A number of large ganoid scales, of the same character as the preceding,
were collected in a sandstone stratum on Little Sandy Creek, during Pro-
fessor Hayden's expedition of 1870. Several of these selected from the collec-
tion are represented in Figs. 35 to 38.

A number of similar scales were obtained by Dr. Carter in the vicinity
of Fort Bridger. Figs. 39 to 42 represent several of the scales selected from
the collection.

Fig. 43 represents a scale of a Lepidosteus found in association with the
large saber-like canines described in the preceding pages, and supposed to
belong to Uintatherium.

Lepidosteus notabilis.

A vertebral centrum partially imbedded in a yellowish sandstone contain-
ing casts of shells was obtained near Washakie, Wyoming, during Professor
Hayden's exploration of 1870.

The centrum is represented in Figs. 12, 13, and appears to indicate a fish
related with Lepidosteus, but probably of a ditfereilt genus. It pertains to
an anterior dorsal, and is about the size of a corresponding centrum of the
alligator-gar, but has the parapophyses much shorter. The centrum also
differs in shape from those of the alligator-gar. The lower surface is broad
and flat, and is marked with longitudinal curved and furcate ridges. The sides
are perpendicular and depressed in a deep fossa beneath the parapophyses
In tiie alligator-gar the sides slant outwardly from the lower surface.

The posterior end of the centrum of the fossil is four-sided, with the
widest border above and convex, the shortest below and straight, and the
lateral borders slanting with a slight sigmoid course.

The short parapophyses project from the upper part of the centrum nearly
from the middle.

The measurements of the specimen are as follows :

Lines

Length of centrum inferiorly 8

Height of centrum posteriorly 9

Breadth of ceutrum at upper part 10

Breadth of ceutvum at lower part- 6

Breadth of ceutrum, iuchuling parapophyses 13

193
PIMELODUS.

PiMELODUS ANTIQUUS.

Among the fossil-fish lemaiiis of Professor tiaydcn's colleotioii from Uic
junction of the Big Sandy and Green Rivers, there are a iiumher of fragments
of pectoral spines and a few jaw-fragments of a species of cat-tish.

The pectoral spines, of which two fragments are represented in Figs. 44,
45, Plate XXXII, are like those of our living cat-fisii. A fragment compris-
ing about two-thirds of the symphysial portion of a dcntary bone. Fig. 46, re-
sembles the same in the recent cat-fish, and, as in it, was covered with a l)n)a(l
card-like surface of teeth. The breadth of the dentary surfiice near the sym-
physis is 3^ lines. The pectoral spines have ranged from an inch to upward
of 2 inches in length. The size of the specie was from a foot to 18 inclies.

PHAREODUS.

PlIAEEODUS ACUTUS.

Accompanying the remains of gars and cat-fish, from i\\{- junction of lh<'
Big Sandy and Green Rivers, there are many fragments of jaw-l)oncs and
others with teeth, evidently not belonging to either of those genera of fislies.
They also present sufficient peculiarity to render it jirobable that they may
not belong in the same family with Amia, and therefore jiroljably not to thc!
closely allied genera supposed to be indicated by the vertebral specimens
described in the preceding pages. The means of comparison at my command
are too scanty to enable me to determine the affinities of the fish to which
the fossils pertain.

Figs. 49, 50, Plate XXXII represent two of the best preserved and more
characteristic of the specimens, consisting of fragments of" dentary bones.
These are proportionately deeper and stronger than in Amia. Tliey su])])oi'f
a single row of long teeth at the border, and possess no patch of smaller
teeth internally such as exist in Amia. The teeth are cylindro-conical, witii
their somewhat thickened liases close together and firmly co-ossified with the
jaw. Tlieir shaft is straight and not curved as in Amia, l)ut thc sharp coni-
cal apex is bent inwardly.

Figs. 47, 48 represent fragments of prcmaxillaries. In these the iccWi
are of the same character as in thc dentary bones, Ijul are less beni at tlic
tips.

•JF,

) c.

104

Fig. 51 represents what 1 suppose to be a fragment of a maxillary ol' the
same fish. It is provided with teeth as in Amia, Salmo, and some other
genera.

Associated with the specimens of the character above described thei-e are,
a number of others, consisting of small fragments of bones with close patches
of short conical teeth, like the vomerine and other similar patches of teeth of
Amia.

The dentary fragment of Fig. 49 contains the remains of a dozen teeth in
the space of 11 lines. The specimen of Fig. 50 contained thirteen teeth within
a space of 10 lines from the symphysis. Of the retained teeth the last is the
longest, and measures nearly 3 hnes. The others are about 2J lines in length.
The premaxillary fragment of Fig. 48 contained seven teeth in a space of as
many lines. The first tooth is the longest, and measures 2f lines. In
the other fragment of Fig. 47, ten teeth occupied a space of 8J lines.

The genus supposed to be indicated by the specimens has been named from
the light-house-like form of the teeth.

EEMAINS OF FISHES FROM THE SHALES OF GREEN RIVER, WYOMING.

In Professor Hayden's Preliminary Report on the Geology of Wyoming
for 1870, p. 142, the author remarks that soon after leaving Rock Springs
Station, on the Union Pacific Railroad, the Green River group is seen on the
bluff hills on either side of the road to the entrance of Bitter Creek into
Green River. In the valley of the latter remarkal)le sections of strata
are exposed to view. The group he calls the Green River shales, because the
strata are composed of thin layers, varying in thickness from that of a knife-blade
to several inches. The rocks all have a grayish-buff color on exposure, some-
times with bands of dark brown. These dai-ker bands are saturated with a
bituminous matter which renders them combustible.

About two miles west of Rock Springs Station there is an excavation on
the railroad which has been called the Petrified Fish Cut, on account of the
thousands of beautiful and perfect fossil-fishes which are found on the surface
of the thin shales, sometimes a dozen or more on an area of a square foot.
Remains of insects und aquatic plants are also found in the shales, and in one
instance a well-preserved portion of a feather of a bird was discovered.

A large collection of fossil-fishes from the Petrified Fish Cut, obtained I)y
Professor Ilaydcn in 1;)70, was subinilted to Professor Cope, who has described
tiie different forms in tlir i('[»orl al)ove mentioned.

195

The first of the fossil-fishes of the Green River shales was discovered by
the late Dr. John Evans as early as 185G, and was submitted to the examina-
tion of the writer. Several specimens, both of the bufi'-colored and dark
bituminous shales, containing fossil-fishes, have been presented to me by
Judge W. A. Carter and Dr. J. Van A. Carter, of Fort Bridger, Wyoming.

Professor Cope describes seven species, including one of those described
by me, from the Green River shales. Two are named Clupea himulis and
C. pusilla, and a third Osteoglossum encaustum. The others are referred to
two extinct genera with the names of Asineops squamifrons and A. viridensis,
Erismatopterus Rickseckeri and E. levatus.

CLUPEA.

Clupea humilis.

The species was originally described in the Proceedings of the Academy
of Natural Sciences of Philadelphia for 1856, page 256. It was indicated
from a specimen consisting of an impression of a nearly complete fish in a
l)iece of shale, which looks like one-half of a rounded, water-worn fragnuMit.
The fossil was found by Dr. Evans on Green River, and was stated by him
to have been derived from the Tertiary rocks of that locality. The fish is
represented in Fig. 1, Plate XVII, of the natural size. It has the ordinary
form of living species of herring, and presents the characters of the genus.

This small herring in its total length has measured about 3^ inches. The
back is slightly arched, and the dorsal fin is situated just in advance of the
middle. The ventral border is strongly arched, and is rather abruptly nar-
rowed from the anus. The ventral fins are placed beneath ihc back of the
middle of the dorsal fin. The head is pointed. The tail is deeply forked,
and its pedicle is rather narrow.

The number of vertebras appears to be about thirty-four, of which at least
twenty are dorsal, tlie remainder caudal. The notochord appears to liave
extended continuously through the perfoi'ated vertebral bodies.

The depth of the l)ody at the fore part of the dorsal fin is four and a luilf
times less than the length. The length of the head slightly exceeds the
depth of the body. The eyes are large.

The pectoral fins are destroyed, but their connection with tli(^ body was
just below the position of the operculum. Tlie ventral liiis ('(nilaiii seven
rays.

196

The dorsal' fin appears to have had thirteen rays, of which the second was
the longest, and from which the others gradually decreased. The anal fin
contains fourteen rays. The caudal fin between its two extreme outer and
longest rays, inclusive of these, appears to possess twenty rays.

The ventral carinated spines are twenty-five. Accessory ribs project from
the vertebrae and ordinary ribs in the usual manner in the herrings.

Measurements of the specimen are as follows :

Lines.

Total length of tbe fish io

Length to commeucement of the tail 34

Depth of body in front of dorsal fin 10

Deiith at anus 0

Length of the head lOi

Depth of the head 8:^

Length of the tail lo"

Depth of iiedicle of the tail 4

Distance from snout to couiinenceiuent of dorsal tin 17

Distance from snout to anus 27

Clupea alta.

A slab of shale obtained from the so-called " Petrified Fish Cut,'' and sub-
mitted to my examination, contains ten herrings, in which the bones and
scales are preserved, and stained of a dark-brown hue. The vertebrae, where
broken, exhibit the position of a continuous notochord occupied by hyaline
chalcedony that looks like the original substance of the latter itself The
most complete and largest of the fossil-fishes is represented of the natural
size in Fig. 2, Plate XVII.

These fishes appear to ])elong to a different species of herring from the
former, especially distinguished hy the greater proportionate depth of the
body and the more arched dorsal l)order. In most other essential character's
the two appear to agree. It has the same number of vertebras and of ventral
carinated spines. The fins also, so far as can be determined, appear to con-
tain the same number of rays.

The other specimens on the slab, though smaller, exhil)it the same, or
nearly the same, proportionate depth of the body.

The measurements of the specimen figured are as follows:

Liiu^s.

Total length of the fish bO

Length to commencement of tail 38

Depth of body in front of dorsal tin Hi

197

Lines.

Depth at anus 91

Length of head 12

Depth of head 10^

Length of tail 11

Depth of iiedicle of tail 5

Distance from snout to coiuinencemeut of dorsal fin 20J

Distance from snout to anus 31

DESCRIPTION OF REMAINS OF MAMMALS FROM THE TERTIARY
FORMATION OF SWEETWATER RIVER, WYOMING.

A small collection of fossils, consisting of the remains of mammals, was
obtained, during Professor Hayden's expedition of 1870, on Sweetwater
River, eighteen miles west of Devil's Gate, Wyoming.

Professor Hayden, in his Preliminary Report of the Geological Snrvey
of Wyoming, 1871, page 32, in relation to the locality whence the fossils
were obtained, makes the following remarks : " Near Cloven Peak, fifteen
miles west of Devil's Gate, there are some bluff-banks on the south side
of the Sweetwater, about one hundred feet high, which indicate the exist-
ence of quite modern Tertiary beds, like those on the Niobrara River.
They are composed of indurated sauds and marls of a light-gray or cream
color, and are in appearance precisely like those seen on the Laramie River,
and many other places, which I have usually regarded as of the Pliocene age.
Still farther to the westward are numerous exposures of these beds, which
are weathered into the usual fortification-like forms, and scattered around
their base are large numbers of remains of extinct mammals and turtles,
apjjarently identical with those found on the Niobrara. They occur in the
same beautiful state of preservation.''

Professor Hayden's view of the age of the formation is confirmed l)y the
zoological character of the fossils, which are nearly related with those from
the Pliocene Tertiary sands of the Niobrara River, and are, without doul)t,
of a much more recent date than those of the Bridger beds.

The specimens sul^mitted to my examination consist of fragments of jaws
with teeth, portions of the larger limb-bones, small bones of the feet, and a
few mutilated vertebrae. Most of them pertain to a species of Merycochoerus,
an animal nearly related to Oreodon. A few apparently belonged to a smaller
species, and several to a small equine animal. The others remain undeter-
mined for want of ready means of comparison.

The fossils are all isolated specimens, which were picked up from the sur-
fixce of the ground. Usually they are perfectly free from adherent matrix.
They are white in appearance, and resemble recent bleached bones. They

199

have losl (licir l)onc-cartilage, and arc linnl and hriUlc, Uiouii^li not (rialilc
Tliey are nut in the least degree water- worn, and present no appearance ol"
having been submitted to great pressure, as is so Irequently the case with the
ossils from the Cretaceous and Eocene formations of neighboring localities.

MAMMALIA.

Ordiir Ruminantia.
MERYCOCHCERUS.

Merycociicerus rusticus.

The genus above named was originally characterized from some remains,
discovered by Professor Hayden during Lieutenant Warren's expedition of
1857, in a bed of dull, fine-grained grit, on the head-waters of the Niobrara
River, near Fort Laramie, Nebraska.

Merycoclioerus pertains to the same family as Oreodon, a genus character-
ized from a profusion of remains from tlie Miocene Tertiary deposit of the
Mauvaises Terres of Wliite River, Dakota. The general construction and
form of the skull appear to be nearly the same, and such, also, is the case
with the number, constitution, and relative position of the teeth. There are,
however, certain peculiarities distinguishing the two genera.

The molar teeth of Oreodon have, comparatively with those of most genera
of existing ruminants, short crowns as in the deer; and, as in this, at matu-
rity they are all inserted alone by fangs. In Merycochosrus the crowns of
the molars are proportionately longer, and in the mature condition of the ani-
mal, while the anterior ones were fully protruded, the posterior ones, though
in functional position, were only partially protruded, and continued to advance
as they were worn away. The difference between the two genera, Oreodon
and Merycochoerus, in respect to tlie comparative length of the molar crowns,
is like that existing between the molars of the deer and the ox, but not to
the same degree. While the condition of the teeth of Oreodon corresponds to
that of the deer, those of Merycochoerus rather hold an intermediate condi-
tion to those of the deer and the ox.

In Oreodon, when the last of the molar series was fully protruded so as to
be inserted by the fangs alone, the anterior molars might still be in a condi-
tion to exhibit very conspicuously the anatomical characters of tlieir triturat-
ing surfaces, as displayed in Plate VII of tlie Extinct Mammalian Fauna of

200

Dakota and Nebraska. In Merycochoerus, on tlie othei- band, lieforc tlie
crown of tbe last molar was fully protruded, ab'eady tbe anatomical characters
of the triturating surfixces of those in advance were, to some extent, destroyed ;
and in the case of tbe first true molar completely obliterated, in this state pre-
senting simply a broad dentinal surface bordered with enamel. This condi-
tion is represented in the Fig. 3, of Plate X, of the same work just mentioned,
though in this case the specimen belonged to an individual past maturity, and
the last molar is fully protruded.

Another distinctive character in the teeth of Oreodon and Merycochoerus is
expressed in the less degree of transverse symmetry of the crowns of the
premolars in the latter. In Oreodon tlieir various measurements are more
uniform, and the summits of the principal constituent lobes of their crowns are
nearly or quite median, and they nearly retained this relative position as the
teeth were worn away. In Merycochoerus the length and fore and aft diame-
ter of the crown exceed the transverse diameter except in the last upper one;
and the summits of the lobes of the premolars, especially in the upper ones,
are more or less in advance of the middle of tlie crowns, and they likewise
retained this relative position as the teeth were worn.

In the original description of Merycochoerus, its distinction from Oreodon
was mainly founded, on peculiarities of the skull; the differences in the teeth
above noted, especially those in the proportionate length of the crowns of the
molars, and their relative mode of protrusion, were not recognized. This
want of appreciation of the distinctive characters of the teeth of the two gen-
era arose from the observations having been made on the jaw-specimens of
Merycochoerus advanced beyond maturity, in which all the teeth were fully
protruded, and in this condition did not strikingly differ from those of Oreodon.

A number of other fossils, discovered by Professor Hayden in the Pliocene
sands of the Niobrara Valley, and described by the writer at the same time
as those referred to Merycochoerus, from the difference in the proportionate
length of the molar teeth in comparison with those of Oreodon, were referred
to another genus with the name of Merychyus. In the same manner this
was supposed to differ from the Merycochoerus; and though subsequently, in
the preparation of the " Extinct Mammalian Fauna of Dakota and Nebraska,"
it was suspected that these two genera migiit prove to be the same, it was
not until the present moment the suspicion appeared to be confirmed. From
present observations and reflection, I am under the impression that Oreodon

201

ami Merycochoerus are two quite distinct though closely allied genera, of
which the latter is geologically the later, and, perhaps, the successor by evolu-
tion from the former. Merychyus would appear to be the same as Meryco-
chojrus, and the fossils which had been referred to it belong to the same geo-
logical horizon.

Of the specimens originally attributed to Merychyus major and M. medius,
too little of the corresponding parts were preserved in such a condition as to
enable us to make a comparison of the upjier jaw and face with the same
parts in Merycochoerus to ascertain how far they are like one another. The
position of the infra-orbital foramen, which appears to be nearly or quite con-
stant in a species, or varies but slightly in several species of a genus, in the
jaw-specimen referred to Merychyus major is placed above the last premolar.
It occupies the same position in Merychyus elegans ; and in the up[)er jaw of
a young animal, referred to Merychyus Jiiedlus, it is placed aljove the last
temporary premolar, therefore agreeing in position with that in tlie adults of
the other two species. In Merycochcej-us proprius the position of the foramen
is further back, al)ove the interval of the first and second molars, and this is,
also, its position in the upper jaw of the Sweetwater species named Meryco-
choerus rusticus.

This difference of position is probably related with adiiference in the shape
of the face, which in ]\Ierycochoerus is rather abruptly narrowed in advance
of the zygomata, as in the hog. The face of Merychyus I suspect rather to
1)0 more like that of Oreodon, nari'owing graduallj' forward from the position
of the orijits and zygomata, as in the peccary.

Admitting the three genera, Oreodon, Merycochoerus, and Merychyus, their
distinctive characters, so far as ascertained from the materials at command,
would appeal' to be as follows :

Oreodon. — Molar teeth with short crowns, as in the deer; and, as in
this, at maturity inserted by fangs. Anterior premolars straight, with the
diameters nearly equal, and with their points median or nearly so. Face
gradually convergent, conical. Infra-orbital arch narrow or of moderate
depth; gradually declining upon the side of the face. Infra-orbital foramen
small and situated al)ove the tliird premolar. Nasal orifice nearly as wide as
high, and situated immediately above the incisive alveolar border, as usual in
most animals. Premaxillaries and maxillaries remaining distinct from one
anotlier. Incisive foramina of moderate size.
•2G G

202

Merycociicerus. — Crowns of the molars proportionately longer than in
Oreodon, and protruding gradually as they were worn away ; the anterior
having their sculptured triturating surface obliterated before the posterior are
fully protruded. Anterior premolars with the length and breadth exceeding the
width, and the upper ones inclining posteriorly, and with their points in advance
of the middle. Facial cone aliruptly narrowed in advance of the orbits.
Infra-orbital arches deep and rapidly declining on the face. Orbits smaller
and more externally situated than in Oreodon. Infra-orbital foramen above
the interval of the tirst and second molars. Nasal orifice situated far above
the alveolar border, as in the tapir, and commencing below as an angular
notch of the premaxillaries, which are firmly co-ossified together and with
the maxillaries. Incisive foramen large.

Meeychyus. — Teeth as in Merycochoerus. Facial cone intermediate in
character to the latter and Oreodon (?) Infra- orbital foramen situated above
the last premolar, or in a position intermediate to that of Oreodon and
Merycoehcerus.

The more characteristic of the remains of Merycochajrus, from the Sweet-
water River, consist of fragments of jaws with teeth from perhaps a half
dozen individuals. One of the specimens consists of the greater part of an
upper jaw, represented in Figs. 1, 2, Plate III, accompanied with a portion
of the lower jaw, represented in Fig. 3 of tlie same plate.

The face of Merycochoerus, as indicated by the upper-jaw specimen just
mentioned, would appear to difter in a remarkable manner from that of the
closely allied genus Oreodon. In the species to which the name of Merij-
cochcerus rusticus has been given, and which probably is the same as Mery-
chyus medius, the face is narrowed in the same abrupt manner in advance of
the orbits as in Merycochcems proprius. It is, however, more convergent than
in the latter, or is proportionately less widened at the extremity.

The relation of the orbits and zygomata to the fore part of the face in
Oreodon is more like the condition in the peccary; in Merycochoerus more
like that in the hog.

The side of the face in If. rusticus between the position of the
orbit and the prominence produced by the canine, and above the alveolar
ridge, is deeply concave, even more so proportionately than in the hog. In
M. propr'ms, it is not depressed in this manner, so that the side of
the face in the corresponding position is nearly vertical, and the large infra-

203

orl)ital foramen opens forward on this vertical surface. In M. rusticiis^ I lie
infra-orbital foramen is also large, and occupies a corresponding position, \n\i
is situated in the concavity of the side of the face, so that the surface of the
alveolar border curves outwardly and downward from it.

The front of the snout or fore part of the upper jaw resembles in its con-
struction the same part in the tapir more than that of Oi-eodon, but, as in the
latter, it barely projects beyond the position of the canine alveoli. The pre-
maxillaries are completely co-ossified with each other and with the maxillaries.

Viewed at the side, the fore part of the upper jaw is convex forward and
downward, as in the tapir. Viewed in front, (Fig. 2, Plate III,) it presents a
long slope, narrow above, widening below, depressed toward tiie median line,
and bounded laterally by the convex curved prominences of the canine
alveoli. About 1 J inches above the alveolar margin the nasal orifice com-
mences in an angular notch as in the tapir, but proportionately less narrow.

Behind the position of this nasal notch, bordered by thickened ridges
ascending in a convergent manner from the canine alveoli, are the lateral con-
cavities of the face before mentioned.

The upper part of the face being broken away, we can form no just idea
of its character. If constructed as in Oreodon, by the conjunction of the
maxillaries along the course of the nasals, it would appear to be exceedingly
narrow, even less than half the width at the alveolar border. It would appear
as if the construction might be somewhat similar to that in tlic tapir, so that
the maxillaries bounded a large nasal aperture overhung by the nasals.

The infra-orbital arch is nearly twice the depth it is in Oreodon, and resem-
bles in its proportions that of the hog. Its outer surface is nearly vertical or
slopes slightly outward, and is nearly plane or slightly depressed. The ante-
rior zygomatic root is an unusually prominent process of tlie maxillary. Its
sutui'e of conjunction with the malar descends nearly on a line with the an-
terior border of the orbit. The latter is smaller, and is situated more exter-
nally than in Oreodon.

Tiie roof of the mouth is moderately concave, and the incisive foramen,
apparently, is proj^ortionately as large as in the tapir.

The lower jaw of Merycochcerus is like that of Oreodon, and, as in this and
all living ruminants, has the rami united by suture.

The mental foramen, like the infra-orbital foramen, is proportionately larger
than in Oreodon. Perhai)s this difference in the size of the ii)ranii:)a, tog<;ther

204

with the other peculiarities of the face, may indicate that Merycochoerus was
provided with large prehensile lips, or probably a short proboscis.

As in Oreodon, the dental series of the upper jaw consists of 3 incisors, 1
canine, 4 premolars, and 3 molars ; of the lower jaw, 4 incisors, 1 canine, 3
premolars, and 3 molars.

In both jaws of Merycochoerus, as in Oreodon, the teeth form nearly closed
rows. The largest interval is between the canine and first premolar of the
upjier jaw, to accommodate the lower canine, which in all the Oreodont family
occupies a position behind the upper one.

A last upper incisor, retained in the upper-jaw specimen of Merycochoerus
rusticus, resembles in its form and relative size to the others the correspond-
ing tooth in Merychyus elegans.

In a fragment of a lower jaw represented in Fig. 5, Plate VII, and retain-
ing most of the incisors, the lateral one is observed to be much larger in re-
lation with the others than in Oreodon. Its crown, viewed in front, is nearly
ovoid in outline. Its borders are acute and meet in a rounded point. The
outer surface is convex. The inner surface, considerably shorter, is bounded
by a basal ridge. The intervening incisors, about half the size of the outer
one, successively but slightly decrease. Their crown is more truncate at the
summit, and the internal basal ridge is stronger. The large lateral incisor is
to be viewed as a modified canine in its relation with this tooth as present in
animals usually.

The canines of Merycochognis in all respects are like those of Oreodon.
As in this genus, the lower ones are to be viewed as modified first premolars,
assuming the form and function of canine teeth, but still holding in relation to
the other teeth the ordinary position of the former.

The crowns of the premolars of M. rusticus in their earlier state are con-
siderably longer proportionately than those of Oreodon, and by the time they
became wholly protruded they were so much worn as to have the peculiar
construction of their triturating surface obliterated.

The crowns of the upper premolars, except the last one, have a backward
inclination, successively increasing from the third to the first. The points
of these teeth occupy the anterior third of the crown in the earUer stage,
and at a late period become so advanced as to appear to form the anterior
corner of the crown. In Oreodon the corresponding teeth are nearly or quite
straight, and the summit of the crown is median, and continues so as the

205

teeth are worn away. The difTerences mentioned — that is to sa}', (he back-
ward inclination of the crowns of the premolars and the more advanced
position of their points in Merycochoerus — wouhl appear to be due to a com-
parative shortening of tlie face and a less consequent space ti)r the dev(dop-
ment of the teeth.

Tlie same ditierences which have been mentioned as existing between tlie
premolars of Merycochceriis rusticus and Oreodon are also obvious in Mery-
chyus elegans. The same may be said also of the third upper premolar in
the fossil referred to MerycJiyus major, except that in this the crown of tlie
tooth is proportionately not so long as in Merycochoirus. rusticus, and was less
worn when fully protruded.

In Merycochcerus rusticus the outer face of the upper premolars is convex
longitudinally, but concave transversely; the lateral borders having a consider-
able degree of pi'ominence. In M. proprius and Merychyus major they are like-
wise concave and bordered l)y a strong basal ridge which is absent in Mery-
cochoirus rusticus. In Merychyus elegans the outer lace of the upper pre-
molars is convex transversely as well as longitudinally, and, as in the latter, is
devoid of a basal ridge.

In a small fragment of an upper jaw of M. rusticus, containing the second
and third premolars, represented in Figs. 3, 4, Plate VII, the crowns are com-
paratively but little worn and retain the characters of the triturating surface.
These teeth are of less breadth in proportion to their thickness than in M.
proprius, and in this respect are more like the corresponding teeth of Oreodon.
Their outer part forms a strong curve from the ends of the fangs to the point
of the crown, of which about one-fourth externally remains unprotruded,
while it is fully protruded internally. The point of the crown is at the
anterior third, and externally it appears to be continuous as part ol" the an-
terior projecting border of tlie crown. The inner portion of the crown ex-
hil)its three deep recesses inclosed l)y prominent loop-like folds. The pos-
terior larger recess is separated fi-om the anterior smaller pair by a ridge
dividing the inner part of the outer or principal lobe of the crown. A basal
ridge festoons the posterior internal loop of the third premolar, but docs not
exist in the second. The teeth are worn olTin a slope on the postero-internal
lace of the principal lobe of the crown.

206

These teetli are sufficiently like the corresponding tooth in the jaw-speci-
men of Merychyus major to render it proljable that this animal may belong to
the same genus as the former.

The last upper premolar of McrycoclicBrus rusticus is like that of M. pro-
jjyius.

The superior molars, the inferior premolars and molars, are so closely like
those of Merychyus elegans, that they may be considered as their magnified
representatives.

Fig. 1, Plate VII, represents a series of upper molars in a specimen in
which the last one has not more than two-thirds protruded. A view of the
outer part of this last molar is introduced in the representation of the upper
jaw in Fig. 1, Plate III, so as to complete the series of upper molar teeth.
In the first molar the anterior crescentic enamel pit is observed to be com-
pletely obliterated, and the posterior one nearly so. In the back two molars
the inuer faces of the internal lobes are decidedly concave longitudinally.

In Fig. 6, Plate VII, we have a presentation of the first and second
upper molars of Merycochoerus proprius introduced for comparison. Tlie
specimen is from the head-waters of the Niobrara River, in the vicinity of
Fort Laramie.

Fig. 2, of the same plate, represents the last premolar and the molar of
the temporary series of M. rusticus. The molar is like those of the perma-
nent set ; the premolar resembles the former modified by having the anterior
lobes, especially the inner one, proportionately less well developed.

In a small fragment of an upper jaw of another young animal, in which the
temporary molars were retained and the first permanent moJar had protruded,
the maxillary presents a different appearance from that in the adult. The
surfaces above and below the position of the ridge produced by the malar
process are almost at a right angle to each other. The upper surface slopes
forward and outward from the position occupied by the orbit, and upon it
opens the infra-orbital foramen about half an inch within the ridge separat-
ing this sui'face from the lower one. In the progress of development from
youth to age the angularity of the outer part of the maxillary became rounded,
so that the surface assumed a convex instead of a nearly rectangular char-
acter.

207

Measuremeuts of the iaws and teeth of M. rustlcus are as follows

Distance from upper inei.sors to back of last molar

Length of space occupied by upper series of molar teeth . . .

Length of space occupied by upper premolarvS

Length of space occupied by ui)per molars

Breadth of upper jaw outside of canines

Breadth of upper jaw outside of second premolars

Breadth of upper jaw outside of second molars

Breadth of upper jaw at inner side of infra-orbital foramina

Breadth of face at lower margin of the orbits

Distance from lower incisors to back of last molar

Length of space occupied by lower series of molar teeth . . .

Length of space occnpied by lower premolars

Length of space occupied by lower molars

Depth of lower jaw at symphysis

Depth of lower jaw below last premolar -

Depth of lower jaw below secoiul molar

Width of condyle of lower jaw

Liues.

53
2'1
31
22
24
30
20
55
62
48
17
31
29
19
22
19

Diameter of upper canine

Diameter of lower canine

Diameter of second upper premolar
Diameter of third upper premolar , .
Diameter of fourth upper premolar

Diameter of first upper molar

Diameter of second upper molar . .

Diameter of third upj)er molar

Diameter of first lower premolar . . .
Diameter of second lower premolar
Diameter of third lower premolar. .

Diameter of first lower molar

Diameter of second lower molar . . .
Diameter of third lower molar

Antero-
posterior.

Lines.

G
5

SJ
-12"
14

7
10
15.^

Transverse.

Lines.
4a

4
5

10-10.}

10^

Of other bones referable to Merycochoerus rmticus, the collection contains
the following:

Portions of several scapulER. The glenoid cavity is oval, and mcasiurs 11
Hnes in its short diameter, and 15 lines in its long dianjolcr, including (he
coracoid process.

208

A numlier of fragments, mostly distal extremities of tibiae, of which one is
represented in Fig. 9, Plate XX. The general construction is the same as
in ordinary even-toed nngulates. The shaft approaching the articulation is
three-sided, with the outer border subacute. This terminates in a triangular
surface for junction with a filjula. The internal malleolus is comparatively
long and pointed, and projects below the position of the anterior process of
the tibia. The articular concavities are nearly of the same extent fore and
aft, but the outer one is much the wider. The width of the end of the tibia
in different specimens ranges from 13 to 14 lines, and the fore and aft diam-
eter is 8J lines.

Of a number of specimens of the astragalus, one is represented in Fig. 10,
Plate XX. It is about the size of that of the peccary, but is proportionately
wider. The outer division of the trochlea is considerably larger than the
inner one. The" posterior articular surface for the calcaneum extends but
little more than half the width of the bone. The length of the astragalus
externally is 16 lines; its width at the lower tarsal articulation is 10^ lines.

Of a number of specimens of the calcaneum, one is represented in Fig. 11.
It is about the size of those of tlie peccary, but is more robust in its propor-
tions. The tuber is a little shorter, but considerably thicker. A peculiarity
of the bone is the absence of a sustentaculum tali, the usual articular surface
of the latter being supported on a moderate expansion of tlie base of the
tuber. The articular eminence for the fibula is but slightly prominent.

The length of the calcaneum is 2i inches; its width at the articulation
below the tuber is 8 lines.

Another specimen of a calcaneum, interesting on account of its diseased
condition, is represented in Fig. 15, Plate II.

Merycochcerus sp *?

Fig. 12, Plate XX, represents the distal end of the tibia, probably of a
smaller species of Merycochcerus. The specimen was found with those
above described. The transverse diameter of the articular end is 11 lines.

An astragalus resembling that above described probably belongs to the
same animal as the latter. It is lOJ lines long, and 5J lines wide.

Order Solidungula.

Associated with the remains of Merycochcerus, from the Sweetwater
River, there arc several bones of a small equine animal, probably a. species

209

ul' llip2)anon. Cue of Uie specimens is an external cnneil'orm bone, of wliicli
an upper view is given in Fig. 13, Plate XX. Another specimen of the same
bone has the navicular bone co-ossified with it. A third specimen consists
of a first ungual phalanx 17 lines long at the side, and 14^ lines wide at the
upper extremity.
27 G

DESCRIPTION OF VERTEBRATE FOSSILS FROM THE TERTIARY
FORMATION OF JOHN DAY'S RIVER, OREGON.

Through the Smithsonian Institution, at tlie suggestion of Professor S. F.
Baird, a collection of fossils was submitted to the examination of Ihc writer
by Rev. Thomas Condon, of Dalles City, Oregon.

The fossils were discovered by Mr. Condon mainly in the valley of Bridge
Creek, a tributary of John Day's River, one of the branches of the Columbia
River. Some additional fossils from tlie same locality were also placed in my
hands by Professor H. S. Osborn, of La Fayette College, Easton, Pennsyl-
vania.

With the exception of a single turtle-bone, the fossils consist of remains of
mammals. In general appearance and condition of preservation they resemble
those of the Mauvaises Terres of White River, Dakota. They are nearly all
specimens which have been found lying loose on the surface of the country,
and are, therefore, more or less weathered, or much injured by exposure. A
few of the fossils are imbedded in, and the cavities of others are filled with,
a liard, compact, homogeneous rock of a bluish-gray hue. The rock ajjpears
to be an indurated marl, and contains abundance of lime. It bears a near
resemblance to the matrix of the fossils of the Mauvaises Terres of Dakota,
except that it is more compact and harder.

The zoological character of the fossils is sucli as to render it probal)le that
the formation to which they belong is of contemporaneous age with the Te.r-
tiary deposit of the locality just named.

The greater number pertain to a species of Oreodon larger than any of
those from White River, Dakota, and about the size of Merycocha'rus proprius
of the Niobrara River, Nebraska.

A number of the fossils appear to belong to some of the same species as
those of the Mauvaises Terres, as Oreodon Culbertsoni, Agrioclimrus antiquus,
and A. latifrons, Jucptomeryx Evansi, Anchltherium Bairdi, and Rhinoceros
occidentalis.

The collections further contain remains of a second species of Rhinoceros,
two species of Elotherium, &c., generally too scanty or imperfect to ascertain
positively whether they pertain to species previously characterized

211

A descrij)live list of tlio fossils is given l)clow :

MAMMALIA.

Order Ruminantia.

OREODON.

Okeodon Culbeetsoni.

This species, established on a multitude of remains from the Mauvaises
Terres of White River, Dakota, is apparently indicated by some small frag-
ments of upper and lower jaws with teeth, which are labeled " Big Bottom
of John Day's River." One of the best-preserved and most characteristic
specimens consists of a jaw-fragment containing the upper last premolar
and the molars, the latter being represented in Fig. 12, Plate VII. In all
respects it is like the corresponding part in Oreodon Culbertsoni, from White
River. Other specimens show a slight variation in the size of the teeth.

Oreodon supeebus.

Nearly twenty-five years have elapsed since the first fossil remains of
mammals from the Tertiary foi-mations of the West were submitted to my
examination. To the present time they have been coming to me in constant
succession, so that I have had the op])ortunity of examining thousands of
specimens, the collective weight of which would amount to several tons.
From some of the first specimens brought from the Mauvaises Terres of
White River, Dakota, after a few errors, I thought I had fixed upon well-
marked characters distinguishing the extinct genus of hog-like ruminants, for
which I proposed the name of Oreodon. Two species were described under
the names of O. Culbertsoni and O. ii;nicills, mainly from a marked difference
in size.

Several detached crania, diifering from that of either of the species of Oreo-
don in the possession of large inflated ear-capsules, at first attributed to a
■peculiar genus with the name of Eucrotaphus, were subsequently referred to
Agriochoerus, which had originally been described from jaws and teeth. Later
this determination appeared to be confirmed by an almost complete skull in
which the cranium agreed with the detached specimens.

Some small fragments, and finally a complete skull, appeared to indicati; a
third and larger species of Oreodon, to which the name of O. majur was given.

212

It is especially remarkal:)le for the great size of the eai--capsules compared
with those of the other species, being proportionately quite as large as those
in Agriochoerus.

Of the multitude of fragments of jaws with teeth, portions of skulls, and
more or less complete skulls of Oreodon, which I have had the opportunity of
examining, by far the greater number are referable to the species O. Culbertsoni,
about a twentieth to O. gracilis, and one per centum to O. major. Specimens
exhil)it more or less variation, generally of a comparatively trifling character,
but in some instances to such a degree as nearly to be distinctive enough for
other species, and in some cases as nearly to remove the distinctions between
the two species O. Culbertsoni and O. gracilis. Two specimens, presenting a
greater extent of variation than usual, have been suspected to represent hybrids
in the one case between O. Culbertsoni and O. gracilis, in the otiier case between
the former and O. major. With the view that they may be specifically dis-
tinct, they have been named O. affinis and O. hijfy-idus.

After a number of years, aaid after having seen many hundred specimens
referable to O. Culbertsoni, to my utter astonishment one of the last ones
received, consisting of the greater part of a skull, while agreeing in every
other respect with the ordinary form of O. Culbertsoni, possesses ear-capsules
as large as those of Agriochoerus. Looking upon this specimen as represent-
ing a species or an importaiit variety, the name of O. bullatus was applied to
it in allusion to its large inflated ear-capsules.

As the cranial portion of the skull of O. bullatus does not differ in size from
the specimens originally referred to Eucrotaphus, we are now uncertain
whether they pertained to O. bullatus or Agriochoerus. They correlate in
size, construction, and form equally well with either.

Some remains from the Niobrara River, Nebraska, while clearly indicating
members of the same family as Oreodon, appeared to me to belong to two
different genera, to which the names of Merycochoerus and Merychyus were
given. The recent discovery of additional remains of anotlier species of
Merycochoerus, on the Sweetwater River, Wyoming, while rendering the ,
characters of the genus more obvious, rather tend to make the genus Mery-
chyus doubtful.

The skull of Merycochoerus has the same general form and construction as
that of Oreodon, and the teeth agree in number, relative position, and consti-
tution. The crowns of the molar teeth in Oreodon are short and inserted by

213

fangs, as in the deer. In Merycochoerus they are longer, and protrude more
gradually as they are worn away. The face is more abruptly prolonged in
front of the orbits ; the infra-orbital arches are proportionately of much greater
depth; and the infra-orbital foramina situated much further back. While the
fore part of the upper jaw of Oreodon is constructed in the more ordinary
manner of many animals — suilline pachyderms, carnivora, &c. — that of Mery-
cochoerus is more like that of the tapir.

Merychyus, so fixr as known, is intermediate in character witli Oreodon and
Merycochoerus. Its molar teeth are like those of the latter ; its face appears
not to be so abruptly narrowed; and the infra-orbital foramina hold an inter-
mediate position.

Another member of the oreodont family, from a formation probably of
equivalent age to that which has yielded the remains of the Oreodons, has been
named Leptauchenia. Its molar teeth agree in character with those of Mery-
cochoerus and Merychyus, but are more strongly folded internally in the case
of the lower ones, externally in the case of the upper ones. The face is more
like that of Oreodon ; has the infra-orbital foramina in the same relative posi-
tion, but has large unossificd spaces at the upper part of the face.

Oreodon superhus, the name which appears at the head of this chapter, was
applied to a species, indicated more recently than any of the preceding, from
specimens belonging to Mr. Condon's collection of Oregon fossils. The species
exhibits characters which make it somewhat peculiar, and place it in a position
intermediate to the White River Oreodons and the genus Merycochoerus. It
is exemplified by a number of specimens, among which is the mutilated skull,
represented, one-half the natural size, in Fig. 1, Plate I. Other specimens,
consisting of detached mutilated crania, portions of others, and fragments of
jaws and teeth, pertain to half a dozen or more individuals.

The skull of Oreodon superhus is about the size of that of Merycocharus
proprius. In form, proportions, and constitution, and in the number, relative
position, and construction of the teeth, it nearly resembles the other known
species of the genus from the Mauvaises Terres of White River, Dakota.

The cranium proper is a magnified likeness of that of Oreodon Culbertsoni
or O. ?n(iJor, and more especially agrees with the latter in the possession of
large inflated ear-capsules. It presents the same kind of variation in different
specimens observed in O. Culbertsoni. In most of the specimens the tempo-
ral surfaces slope from the sagittal crest with a slight sigmoid curve. In one

214

specimen the parietal surface is deeply depressed on each side of the sagittal
crest. In another specimen a pair of well-marked grooves follow the course of
the fore part of the squamous suture, one in front, tlie other behind it. In all
the specimens the front groove is more or less distinct; in some of them the
back groove is bai'ely perceptible.

The auditory capsules are ovoidal, with the greater diameter fore and aft,
and the length exceeding the widtli. They extend from the paramastoid
process forward to the middle line of the glenoid articular surface, and project
below the level of this for half their length.

The face of Orcodon superhus differs from that of the other species of the
genus more than it does among these. It especially differs in the position of
the infra-orbital foramen, and in the great proportionate depth of the infra-
orbital arch. In the other known species of Oreodon the infra-orbital fora-
men occupies a position above the third premolar. In O. superbus it is placed
above the last premolar, as in Merychyus. In Merycochoerus it is placed fur-
ther back over the interval of the first- and second true molars. The infra-
orbital arch is proportionately as deep as in Merycochoerus, and like it presents
a broad, nearly flat surface, extending forward below the position of the lach-
rymal fossa. The latter is relatively shallow. The forehead is more flat than
is usual in Oreodon Culbertsoni. The anterior nasal orifice is like that in other
species of the genus.

The teeth of Oreodon superhus, so far as we have had the opportunity of
examining them, appear to agree in all respects witli those of the other known
species.

Fig. 16, Plate II, represents a fragment of the lower jaw, natural size, con-
taining the premolars and the fii'st molar. A view of the triturating surfaces
of the premolars is given in Fig. 9, Plate VII.

Figs. 7, 8, Plate VII, represent a first molar, part of the second, and the
last molar from a lower-jaw specimen.

Fig. 10, of the same plate, represents a facial specimen, with a view of the
forehead, one-half the natural size.

Measurements obtained from several specimens of portions of skulls of
Oreodon superbus arc as follows :

Estimated length of skull, approximating 14 incbes.

215

Breadth of forehead between orbits on line with supra-orbital

ioramiua

Length of face from orbit to lateral nasal notch ,

Height of face on line with the second true molar

Depth of orbital entrance

Transverse diameter of the same

Depth of infra-orbital arch

Length of upi^er molar series, estimated at

Antero-posterior diameter of last upper molar

Transverse diameter of last upper molar

Breadth of nasals together

Liucs.

50
54
48
21
19
18
70

Lilies.

L'l

174
15i

Lines.

Measurements obtained from lower-jaw fragments detached and not per-
taining to tlie preceding :

Liues.

Lines.

Sjmce occupied by the lower molar series

Space occupied by tire lower premolars

Space occupied bj- the lower molars

Depth of jaw below back of last molar

Depth of jaw below fore part of last molar

Depth of jaw below middle of first molar

Depth of jaw below middle of second premolar
Antero-posterior diameter of first premolar . . .

Transverse diameter of .first premolar

Antero-posterior diameter of second premolar.

Transverse diameter of second premolar

Antero-posterior diameter of third premolar . ,

Transverse diameter of third premolar

Antero-posterior diameter of first molar

Transverse diameter of first molar ,

Antero-j)osterior diameter of second molar

Transverse diameter of second molar

Antero-posterior diameter of third molar

Transverse diameter of third molar

Transverse diameter crown of lower cauine

GO
25
40

41
33
26

7
114

8.J
19J

30J

9
10

^
11

274

31
31

216

LEPTOMERYX.

Leptomeryx Evansi.

A small ruminant, related to the musks, was originally described under the
above name, from remains discovered by Dr. John Evans and Professor Hay-
den in the Mauvaises Terres of White River, Dakota.

Two small fragments of jaws, the one containing a well-preserved upper
molar and the other a lower molar, from John Day's River, agree in all re-
spects with the corresponding parts of Leptomeryx Evansi.

AGRIOCHCERUS.
Agriochcerus antiquus. Agriociicerus latifeons.

The above genus and species were originally characterized from remains
found in the Mauvaises Terres of Dakota. The genus is related with Oreodon,
but exhibits peculiarities enough to regard it as pertaining to another family
of extinct ruminating hog-like animals.

A small fragment of an upper jaw with portion of a molar, and a few frag-
ments of detached molars from John Day's River, appear to indicate the
presence of both the above-mentioned species.

Artiodactyla.

DICOTYLES.

DiCOTYLES PRISTINUS.

An extinct animal about the size of and nearly allied to the living collared
peccary, Dicotyles torquatus, is represented in the Condon collection by
several detached lower molar teeth. These have nearly the size and consti-
tution of those of the collared peccary, though considerably worn and there-
fore smoother than when in a younger condition. Independently of this
smoothness, due to age, the constituent lobes of their crowns do not present
the wrinkled condition observed in the living peccaries.

The last lower molar, i-epresented in Fig. 14, Phite VII, has a five-lobed

.crown with a basal ridge in frout and externally, and also postero-internally.

Tlie lobes of the crown are comparatively simple, or but slightly complicated

by oifsets or folds. The penultimate molar, represented in Fig. 13, Plate VII,

has four principal lobes to the crown, arranged as in the recent peccary.

An upper molar, from a younger animal, perha])s, belonged to the same

217

species. It is more square tlian in the recent peccary, and has llie (pur con-
stituent lobes of the crown comparatively smooth and devoid of wrinkles.

Measurements of the specimens referred to Dicotyles pristinus are as fol-
lows :

Lines.

Auteroposterior diameter of last lower molar 9

Trausverse diameter of last lower molar 5

Auteroposterior diameter of penultimate lower molar 7

Trausverse diameter of peuultimato lower molar ^\

Autero-posterior diameter of lirst or secoud upper moJar 0

Transverse diameter of first or secoud upper molar 5.J

Professor O. C. Marsh has also described some remains of peccaries from
the same locality, which he attributes to two species under the names of
Dicotyles hesperius and Platygonus Condoni. The former is estimated as about
half the bulk of the collared peccary, the latter as being about the size of
the li0£

■'&•

ELOTHERIUM.

Elotherium imperatoe.

Mr. Condon's collection of Oregon fossils contains portions of several teeth
of large size, which are supposed to belong to a huge species of Elotherium,
for which the above name is proposed.

One of the specimens, represented in Fig. 3, Plate II, is a portion of a
large canine tooth, from Bridge Creek. In the perfect condition the tooth
would appear to have measured upward of 7 inches in length. The crown
has measured about 3^ inches long, with the diameter at base antero-posteriorly
about 22 lines, and transversely about 20 lines. The enamel is moderately
rugose, except near the back border of the crown, where it exhibits a more
folded or ridged appearance. The gibbous fang has been over 4 inches in
leneth, with the fore and aft diameter about 2 inches and the transverse
diameter 20 lines.

Another mutilated specimen, from Bridge Creek, supposed to be an upper
incisor, is represented in Fig. 27, Plate VII. When complete, the tooth has
measured over 4 inches in length. The fang is long, conical, and nearly
straight. The crown forms with its fang an obtuse bend or angle. It is
conical, compressed from without inwardly, and has the lateral borders sub-
acute and somewhat expanded toward the base.
28 G

218

A tliii;d specimen, from John Day's River, represented in Fig. 4, Plate II,
consists of tlie greater portion of the crown of an anterior premolar. It is
blunted at the apex as the result of wear. When perfect and unworn it has
measured about 1^ inches in length, about 16 lines antero-posteriorly, and
about 9J lines in thickness.

It is not improbable that part or the whole of the specimens pertain to the
species named Elotherium superbum, from an isolated incisor tooth found in
Calaveras County, California, in the same formation in which was discovered
the specimen of a lower jaw referred to Rhinoceros hesperius.

Solidungula.

ANCHITHERIUM.
Anchitherium Baiedi.

The extinct genus of solidungulate animals, Anchitherium, was originally
described from remains found in the middle Tertiary formation of France.
Abundant remains of a species have also been found in the Mauvaises Terres
of White River, Dakota, which have been described under the name of
Anchitherium Balrdi. The Condon collection contains several specimens,
consisting of detached molars and fragments of others, apparently of the
same species. One of the best preserved of these, the crown of an upper
molar, is represented in Fig. 15, Plate VII. In every respect it agrees with
the upper molars of the Anchitherium Bairdi of White River.

Anchitherium Condoni.

A specimen in the Oregon collection of fossils, consisting of a small jaw-
fragment with a mutilated molar, represented in Fig. 5, Plate II, I have
referred to a species of Anchitherium, though several points lead me to sus-
pect that it may belong to a different though closely allied genus. The gen-
eral form and construction of the teeth are the same as in A. aurelianense and
A. Bairdi. The intermediate lobes of the crown are proportionately larger,
more distinct from the others, and more prominent than in the species just
mentioned. A tubercle springing from the basal ridge between the antero-
interual and antero-median lobes is obsolete in the true Anchitherium.

The diameter of the crown in both directions is about three-fourths of an
inch. The species was named in compliment to the Rev. Thomas Condon,

219

lliruiigli whose iulerch;! ia natural history most of the Oregon fossils have been
brought to the notice of the world.

Perissodactyla.

LOPHIODON?

Among the fossils from Bridge Creek, in the Condon collection, there is a
small fragment of an upper jaw containing two molar teeth, represented in
Fig. 1, Plate II, which proljably indicates a tapiroid animal, allied if not
actually pertaining to the extinct genus Lophiodon. The teeth, which appear
to be the upper back premolars, are much worn, and the last one is mutilated.
They belonged to an animal about the size of the common American tapir,
( Tapirus terrestris.)

The teeth neai'ly resemble the corresponding ones, as we might suppose
them to 1)6 in the same state of wear, of Lophiodon isselense, of the Eocene
formation of France, as represented in Gervais's Plate XVIII, of the Zoologie
et Paleontologie francaises ; or they would appear to bear a nearer resem-
blance to those (A PalcRosyops paludosus of the Bridger Tertiary formation of
Wyoming.

The teeth are inserted with three fangs, two externally and a broader one
internally. The crowns are widest transversely, square without, semicircular
within. They are composed of a pair of pyramidal lobes externally and an
internal median conical lobe embraced by a thick basal ridge. The antero-
external lobe extends in a ridge to the fore part of the base of the inner lobe,
and the postero-external lobe appears to have been continuous by a ridge
with the base of the inner lobe. A thin basal ridge festoons the outer part
of the crown.

In the worn condition of the teeth they present a wide tract of dentine
continuously on the outer lobes. In the penultimate premolar the tract ex-
tends inwardly from the postero-external lobe on the inner lobe, and from
the antero-external lobe to the base of the latter in front. In the last pre-
molar the dentinal surface of the outer lobes extends continuously on the
inner lobe.

The penultimate premolar measures 8J lines antero-posteriorly, and \\\
lines transversely; the last premolar measured about 10 hues antero-poste-
riorly, 11 lines traoisversely.

The size of the specimen, and its apparent rclatiiniship with Lophiodon,

220

led me to suspect that it might pertain to the same animal as an isolated
molar tooth, from the Mauvaises Torres of White River, Dakota, described
under the name of Lopliiodon occidentaUs.

RHINOCEROS.

A number of fossils in the Oregon collection appear to indicate two differ-
ent species of Rhinoceros, or perhaps the hornless form Aceratherium. One
of them was about the size of the Rhinoceros occidentaUs of the Tertiary of
the Mauvaises Terres of White River, Dakota, and was first supposed to
belong to that species. A more attentive examination of its remains has led
to the detection of several peculiarities which render it probable it may be a
distinct species. As the specimens co-ordinate in size with the lower jaw
from the California Tertiary, on which was founded the R. hesperius, they
may perhaps pertain to this species ; and in this view I will so consider them.
Of course, more ample material may confirm or refute our position, and may
determine the fossils to indicate an animal different from 7^. occidentaUs and
R. hesperius.

The second species, a larger animal, intermediate in size to the latter ones,
and the R. crassus of the Niobrara Pliocene Tertiary, has been distinguished
with the name of R. pcmficus.

Rhinoceros hesperius?

The fossils of the Condon collection, attributed with some probability to
this species, consist of a mutilated portion of an upper jaw an isolated upper
molar, and a lower-jaw fragment containing one entire molar.

The upper-jaw specimen contains portions of the fangs of the molars, of
which there were seven, occupying a space of about 7^ inches, or about
equal to that in Rhinoceros occidentaUs.

The anterior extremity of the space included by the zygoma extends to a
line with the interval of the second and third molars; in R. occidentaUs it
extends only to a line with the back part of the last molar.

The infra-orbital foramen is large, and occupies a position alcove the second
premolar; in R. occidentaU's it is over the third premolar.

Tlie upper molar, the last of the series, represented in Fig. 8, Plate II, has
nearly the size and form of that of R. occidentaUs. As in tliis, the crown
consists of a pair of lobes diverging inward from the antero-cxternal corner.

221

A strong bulge iirqjecls from the middle of the anterior lol:)c into the valley
of the crown, which is not so well developed in It. occidentalis, and a second
bulge at the bottom of the valley is absent in the latter. The basal ridge is
stronger in front, and internally at the entrance of the valley of the crown it
forms two conspicuous, rounded tubercles not seen in a corresponding posi-
tion in R. occidentalis. The presence of these tubercles, however, is, perhaps,
merely an individual peculiarity. The tooth measures 15 lines antero-poste-
riorly and internally, and is estimated to have been 19 lines transversely.

The lower-jaw fragment, containing a molar, represented in Fig. 9, Plate
II, exhibits nothing peculiar distinguishing it from the corresponding part
either of R. occidentalis or R. hesperius.

Rhinoceros pacifictis.

The fossil specimens indicative of the second species of rhinoceros from
the Oregon Tertiary consist of a mutilated right side of the upper jaw with
portions of fangs of the molars, except of the first premolar, and several iso-
lated molar teeth.

The specimens indicate a species larger than the preceding, but not reach-
ing Rhinoceros crassus of the Niobrara Tertiary, which was about the size of
the existing India rhinoceros.

The upper-jaw specimen retains portions of the fangs of six molar teeth,
counting from behind. The space occupied by the back two premolars and
the molars is estimated at nearly 7^ inches ; that occupied by the true molars
at rather more than 5 inches.

The fore part of the zygomatic space is on a line with the fore part of the
last molar tooth.

Fig. 6, Plate II, represents an upper molar which is supposed to belong to
this species. The specimen is broken at its back part, and is labeled "Alkali
Flat." The crown at the fore part measures 21 lines in diameter, and is esti-
mated to have measured IJ inches antero-posteriorly. The bottom of the
crown is embraced with a strong basal ridge, which is strongest anteriorly
and internally. The inner lobes expand inwardly, but do not bulge in the
abrupt manner posteriorly to the same degree that they do in R. occidentalis.
The bottom of the oblique valley of the crown is expanded, and is compli-
cated by the projection into it of four folds.

Another tooth, represented in Fig. 7, Plate II, likewise labeled "Alkali

222

Flat," has the appearance in condition of i)reservation, color, and wear, as if
it might have pertained to the same individual as the former specimen. If
so, it is related to it apparent!}' as the last premolar to the first molar. The
antero-posterior diameter of the crown is nearly 16 lines; the transverse
diameter is 19 lines. The basal ridge and inner lobes are as in the former
tooth. Traces at the bottom of the oblique valley appear to indicate a dispo-
sition to the formation of two folds like those existing in the same position in
the larger tooth.

It is not unlikely that this second molar tooth may be a true molar of the
preceding species.

The crown of a lower molar tooth, represented in Figs. 24, 25, Plate VII,
from Bridge Creek, is supposed to belong to R. imcificus. It measures 20
lines fore and aft, and 1 inch transversely, at base.

HADROHYUS.

Hadrohyus supremus.

Among the Condon collection of Oregon fossils there are several, apparently
of a large pachyderm, differing from those previously indicated, and likewise
different in character from such as have been heretofore described.

Fig. 26, Plate XVII, represents a fragment of a tooth which I have sup-
posed to be a last upper premolar. The crown of the tooth would appear in
its entire condition to have nearly the form and construction of the corre-
sponding tooth of the Oreodonts, but differs especially in the proportionately
less degree of development of the inner lobe and the greater degree of pro-
duction of the inner basal ridge. The remains of the inner lobe have the
appearance of being composed of a nearly connate pair, which no doubt
would be found better developed and more distinct in the succeeding teeth.
In the specimen the inner lobe appears notched, and the dentine is exposed
on the outer lobe and the anterior division of the inner lobe.

The transverse diameter of the specimen is 1^ inches. The tooth is
labeled "Alkali Flats," and may be regarded as representing the animal to
which the above name is given.

Another specimen pertaining to an animal as large as that to which the
tooth just described belonged, and perhaps actually belonging to the same,
consists of a brain-cast, or rather the cast of the interior of a cranium. The
cast has nearly the size and shape of the brain of a horse. The cerebral

223

hemispheres arc nearly as much convohitcd as in the latter, and measure
about Ah inches in length and breadth.

A third specimen, which may likewise be suspected as belonging to Had-
rohyus, is a large atlas, which measures 5 inches in width between the outer
acute borders of the articular cups for the occipital condyles, and about 4i
inches from the neural tubercle to the hypapophysis. The vertebra differs in
several important points from the atlas of the rhinoceros, horse, ox, &c., but
the want of the requisite means of comparison prevents me from determin-
ing its nearer relationship.

AN UNDETERMINED CARNIVORE.

A supposed carnivorous animal of large size is indicated l)y the portion of
a large canine tooth, represented in Fig. 26, Plate VII. The specimen per-
tains to the Condon collection of Oregon fossils.

CHELONIA.

TestudinidiB.

STYLEMYS.

The extinct genus of turtles above named, and originally described from
remains found in the Miocene Tertiary formation of the Mauvaises Terres of
White River, Dakota, was most nearly related with the existing land-tortoises.
The shell is of the simplest form, and is about as prominent as in the less
vaulted forms of the living species of Testudo, or the more vaulted ones of
the terrapenes. The proportions nearly accord with those of our southern
gopher, but the carapace is more uniformly convex.

The carapace is most prominent just back of the middle, and is abruptly
rounded posteriorly as usual in the tortoises. The margin is entire, feebly
emarginate in front, somewhat expanded and everted over the axillary spaces,
and in a less degree everted over the inguinal spaces.

The plastron holds the ordinary proportions to the carapace as in Testudo
and Emys. It is for the most part flat, and only moderately turned up in
front. The extremities are nearly equal and rounded. The anterior is
slightly narrowed ; the posterior is moderately notched.

The number, shape, and relations of the bones of the shell are nearly the
same as in Testudo and Emys. The number of the vertebral plates is ten,
occasionally eleven, from subdivision of the usual eighth plate.

224

The ninth plate appears like a correspoiuling pair of costal plates connate
in the median line. The tenth plate is lozenge-shaped, and occupies a
similar shaped interval of the ninth vex'tebral and the pygal plates.

The eight pairs of costal plates in their alternate narrowing and widening
toward the extremities resemble those of the living tortoises, though the
variation is not so great as usual in these.

The interior of the vertebral plates of Styleuiys exhibits a deep, narrow,
keel-like ridge, as represented in Fig. 6, Plate III, and Fig. 9, Plate XIX, in-
tended for union with the neural arches of the vertebrae. A similar con-
dition exists in the Gallipagos and other living tortoises.

The costal capituli, as seen in Fig. 6, Plate III, and Fig. 9, Plate XIX,
are feebly developed as in most species of Testudo, but are not reduced to
the rudimental condition observed in our gopher.

The first pair are as well developed as usual. The sixth and seventh pairs
unite with processes of the corresponding vertebral plates. The eighth and
ninth pairs, better developed than those in advance, unite in the root of the
process of the eighth costal plate for the attachment of the pelvis.

The scutes of both the carapace and plastron of Stylemys correspond with
those of Testudo. The pygal scute is single as in all living tortoises, except
Manouria. The pectoral scutes are very narrow, as usual in Testudo.

The thickness and strength of the shell of Stylemys is greater than ordi-
narily in the latter, liut proportionately not more so than in several living
species.

The bones of the limbs, so far as we are acquainted with them, approach
in character those of the tortoises. The concavity above the articular surface
of the distal extremity of the humerus, but especially of the femur, is deeper
than in the living forms.

The remains of Stylemys are apparently referable to three species, all
geographically and perhaps geologically separated.

Stylemys nebrascensis.

The remains of this species form one of the most abundant fossils of the
Miocene Tertiary deposit of the Mauvaises Terres of White River, Dakota.
A multitude of specimens of nearly entire shells have been collected by all
explorers of the locality in which they are found. Tliey present a great

variety of age, size, aiid coiulilioii ol' prcsicrvalion. Many exhihil in tlicii-
clistortioii evidences of considerable pressure, while others are so well pre-
served as to appear entirely iitibroken. Their varied conditions, added to
slight anatomical variation, led me at first to attribute them to five different
species, which I now view as one.

Mature speciinims are comparatively rare, at least in an entire condition
One, broken into two pieces, is represented in Plate XXIII of "The Ancient.
Fauna of Nebraska."' A second, more complete, was obtained by Professor
Hayden for the Academy of Natural Sciences of Philadelphia.

Very few other bones of Stylemys nebrascensis, other than those of the
shell, have come under my notice. Among hundreds of shells and fragments
of others, I never met with any portions of the skull or jaws.

Fig. 10, Plate XIX, represents a fragment of tlic scapula with part of its
precoraco'id. It agrees with the corresponding portion of the Ijone in Testudo.

Fig. 7, of the same plate, represents the distal extremity of a humerus of
a youtig individual. The hollow above the articular surface is rather deeper
than in Testudo.

Stylemys niobrarensis.

Numerous fragments of shells and a few portions of other bones of a
second species -of Stylemys were discovered by Professor Hayden in the
Pliocene sands of the Niobrara River in the year 1857. • All the anatomical
characters of the specimens indicate the same genus as the former, but
several of them point to a different species. It was about the same size as
the S. nebrascensis.

Fig. 4, Plate III, represents the anterior portion of a plastron of the
natural size, and therefore supposed to have belonged to a young animal. The
episternals are more prouiinent forward than in S. nebrascensis, and they are
deeply excavated beneath the broad scute-covered margin, which is not the
case in the species just named.

Fig. 5 represents the last vertebral and the pygal plates ol" . an
older animal. It shows that the investing scute is single, as in Testudo. The
lower margin of the pygal bone is slightly but decidedly everted, which is
not the case in S. nebrascensis.

Fig. 6 represents an inner view of a portion of a carapace one-halt the
natural size. It belonged to a mature animal, aiul is the most (Complete por-
20 a

226

tion of the shell of the species whicli has been submitted to me. It com-
prises the vertebral plates from the sixth to the ninth inclusive, and portions
of the corresponding costal plates on each side. The narrow character of the
costal capitida is observable in the sixth and seventh pairs ; and the two suc-
ceeding pairs are observable as they spring from the strong process for the
attachment of the pelvis.

Fig. 8, Plate XIX, represents the distal extremity of a right humerus, and
Fig. 6 the same part of a left femur, both half the natural size. The femur
would appear to have belonged to a larger animal than the humerus. The
concavity above the articular surface is much deeper tlian in other known
turtles. The l)readth of the femur, at the condyloid eminences, is 32 lines ;
that of the humerus, in a corresponding position, has been nearly the same.

Stylemys oeegonensis.

An isolated vetebral plate, in the Condon collection of Oregon fossils, is
supposed to indicate a third species of Stylemys. The specimen was found
on Crooked River, and is represented, one-half the natural size, in Fig. 10,
Plate XV. It exhibits a transverse groove defining two vertebral scute areas,
and on the interior a narrow crest for union with the corresponding neural
arch. The plate appears to be the third of the series, and is tliicker in pro-
portion with its length and breadth than would appear to be the case in the
preceding species of Stylemys. The specimen is 2 inches wide, IJ inches
long, and 7 lines thick.

DESCRIPTIONS OF REMAINS OF VERTEBRATA FROM TERTIARY
FORMATIONS OF DIFFERENT STATES AND TERRITORIES
WEST OF THE MISSISSIPPI RIVER.

The fossil remains described in the succeeding pages consist mainl\' of
isolated specimens obtained from Tertiary formations in various parts of the
country west of the Mississippi River. They are nearly all remains of mam-
mals. Included in the series there are descriptions of a few other Tertiary
mammalian fossils, from the country east pf the Mississippi, described on
account of their relation with the former, and for the most part for the first
time.

MAMMALIA.

Order Carnivora.
FELIS.

FeLIS AUC4USTUS.

Several teeth in fragments of jaws, and portions of other teeth, indicate a
sjjecies of tiger apparently diiferent from any previously described. The
specimens were discovered by Professor Hayden, during Warren's expedition
of 1857, on the Loup Fork of the Niobrara Eiver, iSTebraska. They belong
to the Pliocene Tertiary formation, and were found in association with remains
of Mastodon mirificus, Merychyus elegans, Frocamelus occidcHtalis, &^'c.

The most characteristic of the specimens, represented in Fig. 19, Plate VII,
is an upper sectorial molar contained in a small jaw-fragment. The tooth is
about the size of that of the Bengal tiger, and is therefore too large to have
belonged either to the panther or the jaguar. It is as much too small to
have belonged to the extinct American lion, or Felis atrox, as its l)Veadth is
but little greater than the sectorial molar contained in tlie lower jaw from
which the latter was described. The form of the tooth is the same as in the
American panther and Bengal tiger. The breadth of the crown is slightly
less, and its thickness proportionately greater than in the corresponding teeth
of a skull of the latter with which the fossil was compared.

228

If the upper sectorial molar of Fells atrox had the same proportionate size
to the lower one as in the Bengal tiger and other feline animals, it measured
nearly an inch and three-fourths in breadth. That of the Loup Fork fossil
is a little over an inch and a quarter in breadth. From the difference iu size
thus indicated between the sectorial molar of the Loup Fork fossil and that of
the previously described largest American cats, recent and extinct, we -may
fairly regard the specimen as characteristic of another species, for which the
'name heading this chapter has been proposed.

Comparative measurements of the upper sectorial molar are as follows —
those from Fells atrox being estimated, and that from the jaguar being taken
from Plate XIV of De Biainville's Osteographie:

Upper sectorial molar.

F. concolor.

F. onfa.

F. augustus.

F. tigiis.

F. atrox.

Breadth of crown

Tliif'lcnp.ss in front

Lilies.
11
5J

Lines.
12

Lines.

15J

Lines.

Lines.
20
10

Another Specimen, represented in Fig. 18, Plate VII, consisting of a frag-
ment of a premaxillary retaining the second incisor, the first alveolus, and part
of the last one, agrees in size and other characters with the corresponding
part in the Bengal tiger.

The remaining specimens are fragments of an upper last premolar and of a
canine from the same individual.

A specimen, represented in Fig. 24, Plate XX, found by Professor Hayden
on the Niobrara River, but not in proximity with the preceding, consists of
the distal extremity of a humerus, probably of the same animal. It has
about the same size, proportions, and form as in the corresponding part of
the arm-bone of the Bengal tiger. Its diameter at the supracondyles is 3|
inches ; the breadth of the articular surface in front is 2| inches. The hole
for the brachial blood-vessels and accompanying nerve is quite evident, though
the bony bridge defining it is broken.

Felis imperialis.

Among a collection of fossils belonging to the cabinet of Wabash College,
Crawfordsville, Indiana, purchased from Dr. Lorenzo Y. Yates, of Centreville,
Alameda County, California, there are several which were kindly loaned to

229

mc for investigation. The specimens consist of jaw-fragments of a large
wolf and tiger.

Professor E. O. Hovey writes me that they are part of a collection of fossil-
bones which were obtained from a wash in the side of a hill about twenty-
five miles inland from San Leandro, California.

The fossils are not petrified, and indeed have undergone almost no altera-
tion, and are probably quaternary.

The fossil pertaining to a tiger consists of an upper-jaw fragment, repre-
sented in Fig. 3, Plate XXXI, one half size. It contains the second pre-
molar, and retains the alveolus of the one in advance and that of the canine.

The specimen indicates a species as large as the largest living Bengal tiger,
and, indeed, is slightly larger than the corresponding part of the largest spec-
imen of a skull among many in the Academy Museum of Philadelphia.

The proportions of the specimen indicate a larger animal than the extinct
Fells augustus^ as represented by the fossil-fragments from the Niobrara
River of Nebraska. They also indicate an animal as much smaller than the
extinct F atrox, as represented by the ramus of a lower jarw found in associ-
ation with remains of the Mastodon americnnus and Megalonyx Jeffersoni,
near Natchez, Mississippi, as the Bengal tiger is compared with the latter.

Taking into consideration the extent of variation in size of the same
species, there can be no question that the California fossil might pertain to
either the Felis augustns or the jP. atrox. Its associations might aid in the
determination whether it was either of these, or whether it is distinct. If
found in association with remains of Alastodon americanus, it might reason-
ably be supposed to pertain to a smaller individual of Felis alrox ; if with
any of the peculiar species of the Niobrara fauna, it might be supposed to be
a larger individual of F. augustus.

Comparative measuremeuts of the fossil with the corresponding portion of
the skull of a large Bengal tiger from Hindostan are as follows :

Fossil.

Bengal
tiger.

Space occupied by the upper premolars and canine

Lines.
34.0
21.8
1-J. 2
14.0

Lines.
33. .5

From back of lust premolar to canine alveolus

19.0

Antero-posterior diameter of second premolar

12.0

Diameter of canine alveolus . . . . '.

13.5

•

230

CANIS.

Can IS INDIANENSIS.

The fossil specimen pertaining to a wolf consists of the right ramus of a
lower jaw, represented in Fig. 2, Plate XXXI. The specimen indicates an
animal larger than any individuals of tiie recent wolves of North America
and Europe, as represented by skulls I have had the opportunity of examin-
ing in our Museum of the Academy. It, however, indicates a less robust
animal than that formerly described by me under the name of Canis primcevus,
and subsequently as C. indianensis, from an ujjper-jaw fragment, found in
association with reiliains of Megalonyx, &c., on the banks of the Ohio River,
Indiana.

The specimen likewise indicates a less robust species than the C Haydeni,
of the Pliocene formation of the Niobrara River, but a larger one than C.
scevus, of the same formation.

I am disposed to view the specimen as pertaining to the C indianensis,
and perhaps it was not different from the existing C. occidentalis.

Measurements of the fossil, in comjiarison with those of the skull of a large
wolf from the Columbia River, Oregon, and of another from Germany, are as
follows :

Fossil
jaw.

Oregon
wolf.

European
wolf.

Length of jaw from condyle to fore part of canine

Beptli of jawat condyle

Depth of jaw at corouoid process

Depth of jaw at sectorial molar

Depth of jaw at second i^remolar

Length of molar series with caniue . . „

Length of molar series

Anteroposterior diameter sectorial molar

Anteroposterior diameter caniue

Lines.
96.0
21.2-
40.0
18.0
16. G
66.»0
54.0
16.4
8.4

Lines.

90.0
20.5
36.4
17.0
14.0
61. 0
50.0
14.6
6.8

Lilies.

86.0
20.5
37. 5
15.0
12.5
55.4
45.0
14.3
6.2

LUTRA ?

A specimen of a tibia, submitted to my inspection l)y the Smithsonian
Institution, is represented in Fig. 4, Plate XXXI. It was presented by
Clarence King, and was obtained by him on Sinker Creek, Idaho, in associ-
ation with remains of Equus excehus and Mastodon mirificus.

231

The tibia pertains to a carnivore, and resembles Ihat of an otter more than
that of any other animal witii which I have an opportunity of comparing it.
Its differences, excepting size, are trifling. The tubercle for insertion of the
quadriceps extensor is less prominent, so as to give the head of the bone pro-
portionately less thickness in relation with its breadth. The ridge for the
•attachment of the interosseous membrane at the lower part of the bone is
more prominent and sharper. The distal end in front just above the- articu-
lation is flatter, and the groove for the flexor tendons behind is deeper.

Liues.

Length of the bone internally 50

Width of the head 1.5

Thickness at the inner condyle lOA

Width of the distal end between the most prominent points , 11

Thickness at the inner malleole 8

Order Proboscidea.
MASTODON.

Mastodon obscurus.

Besides the well-known American mastodon, M. americaniis, of the post-
Tertiary period, there appear to have been at least three others which in-
habited this continent. Characteristic remains of a species, to which the
name of M. mirijicvfi was given, were discovered by Professor Hayden, in
association with an abundance of remains of many other extinct animals in
the Pliocene formation of the Lonp Fork of Platte River, Nebraska. Re-
mains also, apparently of the same species as the South American M. andium,
have been foOnd in Central America. For an account of the remains of the
two species last named, the reader is referred to the "Extinct Mammalian
Fauna of Dakota and Nebraska."

In the Mnseum of the Academy of Natural Sciences of Philadelphia,
there is a cast in plaster of a mastodon tooth, the original of which is nsputed
to have been found in the Miocene formation of Maryland. The original
specimen having been lost, the cast is represented in Fig. 13, Plate XXVII.
of t-he work just named. This, together with the fragment of a similar
tooth, represented in Fig. 1 6, of the same plate, has been taken in evidence
of the existence of a fourth species, to which the name of M. ohsatrus has
been given.

Dr. Lorenzo G. Yates, of Centreville, Alameda County, California, has
communicated to the writer a list of localities in which he has discovered re-

232 ■ .

iiiaiufi of mastodons in that Stale. Specimens collected by him were sent to
Professor C U. Shrpurd, of Ainlierst, Massachusetts, who has submitted
them to the examination of the author.

One of the specimens, a last inferior molar tooth, represented in Figs. 1, 2,
Plate XXI, was found together with the mutilated lower jaw and upper molars,
at Oak Springs, in Contra Costa County. The remains were obtained from
the rock at the' base of one of the rounded hills, of Tertiary age, mentioned
in Professor Whitney's Geological Survey of California, p. 32, stretching
along near the edge of the San Joaquin plain. According to Mr. William M.
Gabb, the formation belongs to the PHocene Tertiary period.

A small photograph, sent to me by Dr. Yates, exhibits the lower jaw with-
out the ascending portions- behind, and with straight tusks projecting with an
upwar-d direction. The tusks appear to be as long as the jaw was in its com-
plete condition.

The molar tootli has the same general form and constitution as the corre-
sponding one of the American mastodon, but is smaller than is usual in this
species. It resembles the plaster-cast above mentioned sufficiently to render
it pi'obable that it belonged to the same animal.

The crown of the tooth is composed of four transverse pyramidal ridges,
each consisting of a pair of lobes, and conjoined in a common, broad, low
base, without a conspicuous offset- or heel. As in the cast of the Maryland
tooth, the inner lol^es are more mammillary or less angular than in M. ameri-
canus. In this respect they approach the condition, even more marked, how-
ever, in the M. angustidens of Eui'ope, and they are well separated to their
base as in M. americamis. The outer lobes of the crown have the same form
as in the latter, but are provided with distinct offsets projecting from their
inner part fore and aft. The contiguous- offsets come into contact, and thus
obstruct the transverse valleys of the crown. This arrangement accords
with that of the cast of the Maryland tootli. In M. ^wmcrtwws similar offsets
from the outer lobes are usually but feebly developed, and scarcely obstruct
the bottoms of the ti^ansverse valleys.

The enamel worn from the summits of the anterior of the inner lobes
leaves a transverse ellipsoidal cup of exposed dentine, as usual in the same
position in the American mastodon. A greater degree of wearing on the
corresponding outer lobes has produced quadrilobate excavations of dentine,
in which the specimen agrees with the plaster-cast. In the same stage of
wear in M. ainericaniis, the excavations have a more lozenge-like outline.

233

Tlic anterior three divisions of tlie crown arc nearly alike in size and con-
struction. The fourth division is less well developed, and consists of a pair
of conical lobes, but the inner is much smaller than the other, and is connate,,
with a supplemental lube in advance. Back of these there is a small conical
tubercle, corresponding with the heel or rudimental fifth division of the crown
in M. americanus.

In the plaster-cast of the Maryland tooth, the fourth division of the crown
consists of a pair of nearly equal conical lobes, embracing a smaller pair
at their fore part. Behind these there is a pair of conical tubercles corre-
^nding \yith the single one in the California tooth. The ditlerences indi-
cated between the posterior extremity of the crown of the latter and the
cast of the Maryland tooth are not greater than those observed between the
same teeth of diflferent individuals of M. americanus, and are therefore unim-
portant as distinctive characters.

Well-developed elements of a basal ridge, in the California tooth, occupy
the outer fore part of the crown and the intervals of the outer lobes. Between
the posterior three divisions of the crown they are better marked than in the
cast of the Maryland tooth, or even than is usually the condition in the
American mastodon. The ridge is also distinctly produced around the outer
part of the third and fourth external lobes and the back of the crown, which
is not the case in the cast, nor usually in M. americanus.

The jaw-fragment containing the tooth is too much mutilated to ascertain
anything of importance in regard to it, other than that it measured about 6.^
inches in depth at the fore part.

. Comparative measurements of the California tooth, the cast of the Mary-
land tooth, and two teeth of M. americanus are as follows :

California.

MaryhuKl.

M. americauns.

Female.

Male."

Fore and aft diameter of crowu

Breadth at anterior tliree ridges

Breadth at fourth ridge

Height of third inner lobe, unworn

Lines.
75
33
25
25
10
■ 24

Lines.
75
33
28
26
20
22

LAncs.
75
38-42
33
28
20
22

Lines.

41-45

Height of fourth inner lobe

Height of fourth outer lobe

' The 8i>ecimeu of the tooth of a male has iive transverse divisions to the crown in addition to a small

heel.

30 G

. 234

The second specimen received from Professor Sliepard consists of the
fragment of a tusk, from Dry Creek, Stanislaus County, California. It was
discovered by Dr. Yates imbedded in the bluff of a hill, about ten feet above
the bed of the creek. The hill, upward of a hundred feet in height, is one
of those mentioned in Professor Whitney's Geological Sux-vey as being
scattered over the San Joaquin plain, at the base of the foot-hills of the
Sierra Nevada.

The specimen is represented in Figs. 3, 4, Plate XXI, and is remarkable
from its exhibiting characters which indicate the species to have been nearly
related with the Mastodon augustidens of Europe. The molar tooth frdit
Contra Costa County, likewise presents a form which approximates it to the
same animal, so that it is probable both specimens may belong to the same
species.

The fragment is six inches long, sliglitly curved in two directions, and in
transverse section (Fig. 3) is ovate, with the anterior pole acute. The pulp-
cavity, opening half the diameter of the tusk at its larger broken end, extends
half the length of the specimen. On one side of the tusk, as in Mastodon
augustidens, there is a broad layer of enamel, which extends from the acute
border two-thirds the width of the specimen. The enamel is somewhat
rugose, and is two-thirds of a line thick. In one position, near the smaller end
of tlie fragment, it has been worn through irregularly for the extent of about 1 J
inches. The convex or thicker border of the tusk has also been worn off to
an extent of two-fifths of the surface. The broken ends of the fragment exjiibit
the usual decussating lines of structure of the dentine so characteristic of
the ivory of the great proboscidians.

The entire length of the tusk appears to have approximated two feet. The
other dimensions are as follows :

Linos.

Long diameter of the larger extremity 28

Short diaTueter of the larger extremity 19

Long diameter of the .smaller extremity 22

Short diameter of the smaller extremity IG

Breadth of enamel layer at larger extremity 22

Breadth of enamel layer at smaller extremity 19

In the form of the tusk and the possession of an enamel band it resembles
the same organ in the Mastodon augustidens. The specimen when first de-
scribed was viewed as probably representing a species distinct from that to
which the Contra Costa specimens pertained, and was therefore referred to an

235

animal with the name of Mastodon Shcjmrdi, in honor ot" Professor C. U.
Siicpard.

Since writing the above, I have received another specimen from Professor
Shepard, consisting of a last inferior molar tooth, obtained hy Dr. Yates in
Contra Costa County, California. It is almost identical in form and size with
the one previously described from the same locality, but appears to have l)e-
longed to an older individual, as indicated by the more worn condition.

From the Smithsonian Institution I have recently I'eceived for examination
some remains of a mastodon and an elephant, which were found near Santa
Fe, New Mexico, and were presented to the institution by the Hon. W. F.
M. Arny. The mastodon remains consist of three fragments of a lower jaw,
a vertebral body, and a rib-fragment. They are white, and from adherent jior-
tions of matrix appear to have been imbedded in an indurated clay. The
cancellated structure of the bones is filled with the same matter together
with crystalline calcite.

The lower-jaw fragments appear all to have pertained to the same specimen.
One of them, repi'esented in Fig. 1, Plate XXII, consists of a portion of the
right ramus containing the last molar tooth nearly of the size of the corre-
sponding part in the American mastodon. The molar tooth, represented in
Fig. 4 of the same plate, has lost the portion back of the third ridge of the
crown. The portion preserved sufficiently resembles in its construction the
corresponding portion of the California tooth above described to behmg to
the same species, which I suspect actually to he the case. It also resembles
more nearly the corresponding portion of the same tooth of M. augustidens
of Europe than it does that of the M. americanus.

The other jaw-fragments, represented in Figs. 2, 3, form together the
anterior, extremity of an enormously prolonged symphysis, like that of J/.
augvstidens. The specimen is rather more than a foot in length, and contains
jiortions of tusks extending through the pieces and broken ofl" on a level with
the extremities of the .symphysis. This has been somewhat crushed laterally,
so as to disarrange the proper relative position of the two tusks. It is ot
nearly uniform width, but widens at the posterior extremity. Below, it is
slightly convex or nearly straight longitudinally, and is depressed along the
median line. The sides are convex, and extend upward in ridges which form
the boundaries of a deep groove at the upper part of the symphysis. The
groove is narrower behind, and becomes shallow in front. The tusks are

23()

slightly compressed cylindrical, and curved in their course. They are oval in
transverse section, with the long diameter directed from within upward and
outward. They are unprovided with enamel, and at the broken ends exhibit
the decussating curved lines of structure of the ivory enveloped in a thick
layer of dense cementum. At the posterior extremity the broken ends ex-
hibit the pulp-cavity occupied with matrix and surrounded with a margin of
about a line in thickness, so that the symphysis is broken off near the bottom
of the incisive alveoli.

Frooi the thinning of the anterior alveolar borders of the symphysis it
would appear as if the latter was nearly complete, so that if we Siippose the
lower tusks projected about 6 inches from the jaw, it would give them an
entire length of about 20 inches.

The breadth of the fore part of the symphysis, in its complete condition,
is rather more than 5 inches. At the back part, corresponding with ttie posi-
tion of the bottom of the incisive alveoli, it has been about an inch wider.

The long diameter of the tusks, at their anterior broken ends, is about 20
lines; the short diameter 17 lines. These diameters are nearly uniform
throughout as existing in the specimen.

The fore and aft diameter of the last molar tooth, when complete, is esti-
mated to have been full (ij inches. The width of the crown at the base of
the second and third ridges is 35 lines. The measurements indicate the pro-
portioBS of the tooth to be slightly greater than in the corresponding Califor-
nia tooth or the cast of the Maryland toyth.

The depth of the lower jaw below the second ridge of the last molar is 6^
inches ; and the thickness is 5 inches.

I think it probable, without being positive in the matter, that the Masto-
don remains above described, which have been referred to species under the
names of Mastodon ob.scurus and M. Shepardi, including those from New Mex-
ico, belong to one and the same species. This, from the form of the molar
teeth, the constitution of the upper tusks, and the prolonged symphysis of
the lower jaw, was clearly a near relation of the Mastodon augustidens of
Europe.

In a note, on page 74, of volume II, of the Palaeontological Memoirs of the
late Dr. Falconer, it is stated that at Genoa he had seen a cast of a lower jaw
of a mastod'on from Mexico, with an enormous iec abruptly deflected down-
ward, and containing one very large incisor. The beak is much thicker than in

237

M. augusUdens and larger than in M. loitgirostris. • ".The outline of the jaw re-
sembles very uuich the figiira in D'Orliigny's voyage, descriljed by Laurillard
as M. andium. The Genoese paleontologists had named it lihynchotherium,
from the enormous development of the beak, approaching Dinotherium.''

Perhaps this Mexican specimen of a lower jaw may pertain to the same
species as the specimens above described, though tlie beak of the New Mex-
ican specimen is unlike that of the figure above alluded to in tiie work of
D'Orbigny.

The vertebral body and rib-fragment accompanying the jaw-fragments from
New Mexico present nothing remarkable. The former is of a lumbar verte-
bra, and would indicate an animal about as large as the living Asiatic elephant.
Its length is 34 lines; its breadth is about-5 inches at the posterior border;
and its height is 3^ inches.

Mastodon mirificus.

Some small fragments of jaws and teeth, apparently referable to this species,
in the museum of the Smithsonian Institution, were obtained by Mr. Clarence.
King, from Sinker Creek, Idaho.

Mastodon amkricanus.

Among a collection of remains of the American mastodon, from Benton
County, Missouri, deposited in the museum of the Academy of Natural Sciences
of Philadelphia by the American Philosophical Society, there is a singular'
tooth, which I suppose to be of abnormal character and to pertain to the
Mastodon americanus. The specimen is in the same state of preservation as
the associated remains, and is repre.sented in Figs. 5 and 6, Plate XXII. It
consists of the complete crown of a molar tooth without the fangs. Its shape
is so peculiar that I can form no clear idea as to the relative position it occu-
pied in the jaws, or as to its homologous character in comparison with normal
teeth.

The crown in transverse outline is irregularly oblong oval, more bulging
on one side than the other, and somewhat prolonged at the extremities. From
a thick expanded base there project four conical lobes, of which the interme-
diate two are nearly equal and nearly twice the size of the others, also nearly
equal in size. The basal ridge on the more prominent side of the crown is
mammillated, and twice the depth that it is upon the other side, in which
l)Osition it is comparatively smooth.

238

The long diameter of the crown is 55 lines ; the short diameter, 29 lines.

A small collection of fossil teeth, from near Pittstown, on the Susquehanna
River, in Luzerne County, Pennsylvania, now jjreservecl in the Museum of the
Academy of Natural Sciences, is of interest on account of the association.
The specimens consist of two molai's of Equus major^ hereafter described, a
molar of Bison kU/frons,.£dso to be described, and three first premolars, ap-
parently from as many different individuals of Mastodon americaiius. Of these
one is represented, of the natural size, in Fig. 9, Plate XXVIII.

ELEPHAS.
Elephas americanus.

In the preceding account of the remains of mastodon from near Santa
Fe, New Mexico, those of an elephant are referred to which were found
in association with them. There is but one specimen, consisting of the back
part of a molar tooth, apparently the last upper one. It is composed of eight
unworn lobes, decreasing successively in length. They present the ordinary
thin, elongated, palmate appearance, with the digitate extremities curving for-
ward and ending in manimillary points. The eight plates occupy a space
of 4| inches. The second of 'the .plates is 3f inches broad near the middle,-
and when entire was upward of 7 inches in length.

The specimen is insufficient to determine whether it pertained to a species
different from the ordinary Eleplias amei-icanus, and it presents nothing pecu-
liar. The thickness of the lobes, or double plates, indicates the coarse-plated
variety of teetli of the American elephant, named by Dr. Falconer Elephas
columhi.

Since the above was written I have received; from the Smithsonian Insti-
tution, for examination some remains of an elephant from Chihuahua. Pro-
fessor Baird rej)orts that the remains came from an ancient lagoon-bed at
Potos Spring, seventy-five miles south of El Paso, Texas, and were presented
to the institution by General Carleton, United States Army.

The specimens consist of fragments of molar teeth with adherent gravel,
and with the exterior cementum much worn away by water action. Tliey
indicate the coarse-plated variety of teeth of the American elephant. One
of the better preserved specimens consists of the fore part of a last lower
molar about one-third worn down. It comprises about eight lobes, or double
plates, included in a space of 5| inches. The width of the sixth lobe is 3*f

239

inches. The first lobe is nearly obliterated, and its back plate conjoins tlie
contiguous one of the second lobe.

Another specimen consists of the ])ack part of a molar with six lobes,
occupying a space of nearly 4^ inches. The lobes exhibit the same narrow,
elongated, palniated form, with curved digitate extremities, as in the molar
fragment from New Mexico. The first of the six lol)es is worn off at the
summits of the digitate ends. The others are unworn, and the second plate
is 3| inches wide near its middle.

MEGACEROPS.

Megaceeops coloradensis. ■

An imperfectly known extinct animal, which was supposed to be related
with the great ruminant, the Sivatherium of the Tertiary formation of the
Sewalik Hills of India, is indicated by a singular looking fossil discovered in
Colorado. The specimen belonged to Dr. Gehrung, of Colorado City, by
whom it was presented to Professor Hayden. It is represented one-half the
natural size in Figs. 2, 3, Plate I, and Fig. 2, Plate II, and was originally
described in the Proceedings of the Academy of Natural Sciences of Phila-
delphia for January, 1870, under the name heading this article.

The fossil is singularly puzzling in its character, and possesses so little in
common with the homologous portion in ordinary animals that its relation-
ship would have remained unknown, or entirely conjectural, had we not been
previously acquainted with the Sivatherium. The specimen appears to cor-
respond with that portion of the face of the latter which comprises the upper
part of the nose, together with the forehead and the anterior horn-cores. As
is described to be the condition in the corresponding portion of the skull of
Sivatherium, all the bones entering into the constitution of the fossil are
completely co-ossified, so as to leave no traces of the original course of the
sutures. The nasal and contiguous bones arc of great thickness, and as solid
as those generally in the living Sirenians.

The horn-cores of the Colorado fossil resemble the anterior ones of Siva-
therium both in form and relative position. They are large, dense, conical
knobs, somewhat trilateral, and with a rounded, dome-like smnmit, which is
more porous on the surface than any other part of the fossil. They are
nearly straight, and divergent from each other, and their summits project
more over their base externally than in Sivatheriinn.

240

The space between the horn-cores extending across the forehead forms a
deep concavity divergent outwardly. The surface of the forehead from the
broken border of the specimen behind to the end of tlie nasals forms a mod-
erate uninterrupted convexity. In Sivatherium, the rhinoceros, and the tapir,
the corresponding surface is interrupted by a concavity at the root of the nose.

The face, as formed by the nasals and tlicir apparent conjunction with the •
maxillaries in advance of the position of the horn-cores, is exceedingly short
in comparison with the corresponding part in Sivatherium and the rliinoceros,
and is more like that in the tapir.

The nasals together form a strong, thick, tongue-like process, projecting
free from their conjunction with the frontals in advance of the horn-cores.
The overhanging process of the nose is proportionately wider, thicker, and
longer than that of Sivatherium. Its upper surface is not vaulted as in the
latter and the rhinoceros, but simply continues the convexity of the forehead.
The lateral margins are sqmewhat expanded, (not sufficiently expressed in
Fig. 2, Plate I,) and are thinner than elsewhere. Tlie end is thicker than at
the sides, is more obtuse than in Sivatlierium or the tapir, and is roughened
and porous, probably to have given firmer attachment to a proboscis. A
notch occupies the extremity of the obliterated internasal suture.

One of the most remarkable characters of the Colorado fossil is the great
comparative extent of the lateral nasal notch. It not only exceeds that of
Sivatherium, but also that of the rhinoceros and tapir. In the former its
bottom is far in advance of the position of the lK)rn-cores, and in the rhi-
noceros it holds nearly the same relative position. In the tapir the notch
extends back over the position of the orbits. In the Colorado fossil it
extends far back beneath the position of the horn-cores, wdiere the nasals
apparently conjoin the maxillaries. The relative position of the orbits cannot
be ascertained in our fossil, as all the contiguous parts are broken away.
They appear as if they had been situated farther posteriorly in relation with
the position of the horn-cores than in Sivatherium. The horn-cores, project-
ing forward and outward, overhang a large recess, which would appear to
have been just in advance of the orbit, and is situated externally above and
behind the lateral nasal notch.

The broad and stout projecting nasals were probably intended as a point
of attachment for a movable snout or proboscis, intermediate in degree of
development to that of the tapir and elephant or mastodon. The similar

241

constitution of the nose ot SivHtlieriiuu led ils (li.scoverei- and descriher, Dr.
Falconer, to attribute a like prehensile organ to tiiat animal. The strength
and co-ossitication of the nasals, together and with the frontals and niaxilla-
ries, are also no doubt related with the unusual position of the horn-cores, just
as a similar condition of things in the rhinoceros is related with the support
of a Iiorn on the nose.

^[(gacerops coloradcnsis is estimated to have approximated two-thirds the
size ot the Sivatherium g'lganteum.

Measurements from the fossil referred to Mpgacerops coloradenus are as
follows :

luches. Liues.

Distauce from the summit ot oue horucore to tbe otlicr ' 10 0

Length of curve between the same two poiuts I'j 10

Length of Literal nasal notch from end of nasals 1 0

Distauce from end of nasals to center of space between liorncores 0 0

Breadth of nasals 2^ inches behind the end 4 o

Thickness of nasals where co-ossifiod ... « 1 3

Diameter of born-cores 2i inches from summit fore and aft 2 10

Diameter of horn-cores 2^ inches from saiiuuit transversely 2 5

Breadth of face below born-cores 8 8

Breadth at bottom of lateral nasal notches 5 6

Since writing the above, I have recalled to mind a specimen of a horn-core
which was obtained by Dr. John Evans from the Mauvaises Terres of AVhite
River, Dakota, and which is noticed in the account of Titanotherium, on page
216 of the " Extinct Mammalian Fauna of Dakota and Neliraska," The ref-
erence of the specimen to any particular animal was considered very uncer-
tain, though it was suspected that it might pertain to Titanotherium. It is
now represented in Fig. 3, Plate XXVIII, and is seen by comparison to bear
a near resemblance to the horn-cores of Megacerops. It is rather larger and
slightly more tapering and curved than in the latter. The specimen may,
perhaps, belong to another species of Megacerops.

Since the foregoing was written. Professors Marsh and Coi)c have repoiied
the discovery of i-emains of several huge nuimmals in the Bridger Tertiary
beds, which they have described under the names of Tinoceras, Dinoceras,
Eobasileus and Loxolophodon. The ordinal relations of these is a matter of
dispute, and it is a question especially whether they are proboscideans, or are
representatives of a previously unknown order. One of their most remarkable
pecuharities is the possession of several pairs of bony jirotuberances to the
skull, which are viewed as horn-cores.
31 G

242

In a recent paper cntilled '-00 the Gigantic Fossil Mammals of the Order
Diiiocerata,'' by Professor Marsh, published in the American Journal of Sci-
ence for February, 1873, there is a representation of an almost complete skull,
described under the name of Dinoceras mirahilis. This skull, which appears
to agree with the corresponding parts, including the teeth, described in the
preceding pages under the name of Uintatherium rohustum^ is represented
with three pairs of bony protuberances, or horn-cores. In comparing the
Colorado fossil, it would appear that the lun-n-cores accord with the second
pair of the Wyoming fossil, in which they are seen to spring from the upper
part of the maxillaries, where these join the nasals.

The resemblance between the si^ecimen belonging to Megacerops and the
skull described by Professor Marsh renders it probable that the former
belongs to the same order, instead of to the ruminants, as previously sup-
posed.

Order Solidungula.

EQUUS.

Equus occidentalis.

I The remains of equine animals which of late years have been discovered
both in North and South America indicate a number of species and genera
really wonderful, when we take into consideration that neither continent pos-
sesses a single living indigenous species. The reiliains from many parts of
North America, mainly consisting of isolated molar teeth, which have come
under my observation, exhibit so much difference in size and variation of the.
enamel- folding, as displayed on the worn triturating surface, that in many
cases I have fliiled to refer them to species with any degree of certainty.

In the Proceedings of the Academy of Natural Sciences of Philadelphia
for 18(J5, page 94, I have given a notice of two specimens of upper molars
from California, submitted to my examination by Professor J. D. Whitney,
which were referred to a species uith the name of Equus occidentalis. One
of these specimens is represented in Fig. 2, Plate XXXIII, and was obtained
from auriferous clay, at a depth of thirty feet from the surface, in Tuolumne
County, Cahfornia.

Subsequently, in the same Proceedings for 1868, page 26, and in the
"Extinct Mammalian Fauna of Dakota," &c., I described a number of re-
mains obtained by Professor Hayden on Pawnee Loup Fork of the Platte

243

River, and on the Niobrara River, Nebraska, which I referred to a species
with the name of E. excehus. A characteristic specimen referred to the latter
consists of a portion of the upper jaw containing the back four molars, repre-
sented in Fig: 31, Plate XXI, of the work last named. The teeth in this
specimen are so nearly identical in character with those from California,
referred to E. occidentalism as may .be seen by comparing the figure with
Figs. 1, 2, Plate XXXIII, of the present work, that there can be little doul)t
of the two named species being the same.

Since the original description of the two specimens referred to E. occiden-
talism I have seen others of half a dozen ditferent individuals from California.
All these present sufficient correspondence in peculiarity of character as to
render them fairly representative of an extinct species, for which the name
of E. occidentalis is appropriate. Fig. 1, Plate XXXIII, represents a series
of the anterior four upper molars contained in a jaw-fragment. Tlie speci-
men, together with another similar one fiom a second individual, and contain-
ing all the molars except the last one, were obtained by Dr. George H. Horn
from an asphaltum deposit near Buena Vista Lake, California, and presented
to the Academy. Similar specimens have also been submitted to my exam-
ination, obtained at the same locality by Professor Whitney.

The upper molar teeth of E. occidentalis are about the size of those of the
larger varieties of the domestic horse. From them they arc in general
readily recognizable l)y the greater simplicity in the course of tlie enamel
lines, as displayed on the worn triturating surface, and in the absence of the
small enamel-fold, directed inwardly, at the bottom of the oblique valley
between the inner principal folds of the crown, in wliich point these teeth
accord w'ith those of the existing ass.

The measurements of the specimens referred to E. occidentalis and repre-
sented in the figures are as follows :

Specimen of Fig. 1.

Diameter of first molar . .
Diameter of second molar
Diameter of third molar . ,
Diameter of fourth molar.

Autero-
liosterior.

Transverse.

iiwes.

Lines.

14^

14J

144

14.i

12i

134

244

Speciincii ot Fig. "2, representing a second ur third molar :

Lines.

LcTigtb externally 127

Autero-posterior diameter of triturating surface 15j

Transverse diameter 13i

A tooth in the collection of" the Smithsonian Institntion, apparently refer--
al)le to the same species, was discovered by Mr. Clarence King on Sinker
Creek, Idaho.

Equus major.

Figs. 3 to 1 7, Plate XXXIII, represent specimens, from different localities
of the United States, which are viewed as pertaining to an extinct horse,
originally referred by the author to a species under the name of Equus com-
plicatus, and which is suspected to be the same as that which was first desig-
nated by Dr. Dekay under the name of Equus major.

Figs. 3, 4, 7 to 10, 12, 13, represent specimens of teeth submitted to my
examination by Messrs. D. C Elliot and George N. Lawrence, of New York.
They were obtained from an asphaltum-deposit and from a stratum of clay
beneath, in Hardin County, Texas, and were found in association with remains
of mastodon and other extinct animals.

Figs. 3, 4 represent a first upper molar of the right side. It differs in no
important degree from the corresponding tooth of the domestic horse, l)ut is
somewhat larger than usual, and is less simple in the course of the enamel
lines on its triturating surface.

Figs 5, 6 represent a similar tooth, from Illinois Bluffs, Missouri, six miles
west of Saint Louis. According to the late Dr. B. F. Shumard, it was derived
from the quaternary formation of Missouri.

Figs. 7, 8 represent a last superior molar of the right side, accompanying
the first molar, from Hardin County, Texas. It is remarkable for its great
extent of curvature compared with the corresponding tooth in the recent
horse. The arrangement of the enamel is similar to that in the latter, and is
but little more complex than usual.

Fig. 9 represents a last lower molar, and Fig. 10 a fifth lower molar. These
present nothing peculiar distinguishing them from the corresponding teeth of
the recent horse.

Fig. 11 represents a second or third upper molar of the right side. The
specimen was found liy Dr. Thomas H. Streets, in a gully of Galveston Bay,

Texas, and prosoiited hy him to llic Academy of Philadelphia. In the eom-
plexity of lijlding oi" the enamel, as seen on the triturating surl'aee, this looih
is quite characteristic of Eguus comjdicatus.

Fig. 12 represents a first lower temporary molar, one of tlie specimens from
the asphaltum-bed of Hardin County, Texas.

Fig. 13 represents an. upper last temporary molar, another of the specimens
from the locality just indicated.

Fig. 14 represents an upper molar of Equus complicatus from the " phos-
phate-beds" of Ashley River, South Carolina.

Fig. 15 represents an inferior molar from the same locality. The upper
molar, in the complex condition of its enamel-folding, i§ characteristic of the
species. The lower molar presents nothing distinctive from those of the
recent horse.

Teeth of horses are frequently found in the Ashley phosphate-beds, mingled
with abundance of fossil shai'k-teetli, remains of mastodon, elephant, &c.
Many of them are undistinguishable from those of the recent horse, but others
in size and complexity of the enamel-folding in the superior molars are suffi-
ciently characteristic of Equus compUcatus.

Figs.' 16 and 17 re|)resent an upper and a lower molar, which were found
associated with remains of mastodon at Pittstown, on the banks of the Sus-
quehanna River, Luzerne County, Pennsylvania. . The teeth are more than
half worn away. Their size, and a rather greater degree of complexity than
usual in the enamel lines of the triturating surfece of the upper molar, would
probably indicate that they belong to Equus conqdicatus.

Measurements of the specimens, represented in-Figs. 3 to 17, and referred
to E. compllcatits, are as follows :

First upper molar, Figs. 3, -1.— Leugtli of crown externally, 35 lines ; antero-posterior
diameter. 21 Hues; transverse diameter, 15 lines.

First upper molar, Figs. 5, C— Length of crown, 33 lines; antero-posterior diameter,
21 Hues; transverse diameter, 15J lines. .

Lust upper molar, Figs. 1, 8.— Leugtli at antero-extermil border from end of fang, 3G
lines; length posteriorly ,,19 lines; breadth of triturating surface, 10 lines; width, 21
lines.

Last lower molar. Fig. 0.— Breadth, 10.^ lines; width, 7 lines.

Fourth or fifth lower molar, Fig. 10.— Length of crown, 34 lines; breadXh, 13i lines;
width, 73 lines.

U2)per second or third molar, Fig. 11.— Length of crown, 32 lines; breadth, 11 lines;
width, 15 lines.

First lower temporary molar, Fig. 12.— Breadth, 174 lines; width, 8 lines.

24G

Last vpper iemporunj molar, Fig. lo. — Bicadtli, 17 linos; width, ]0 lines.

Ujyper second or third molar, Fig. 1-1. — Length of erown, U.j lines; breadth, 14 liues;
width, 13 lines.

An intermediate lower molar, Fiij. 15. — Length of crown, 134 liues ; breadth, 13^ lines;
width, 9J liues.

TIpi)cr molar, Fig. IG. — Length of crown, 22 lines; breadth, 13i lines; width, 14J liues.

Loiver molar, Fig. 17. — Length of crown 22J lines ; breadth, 14| liues ; width, 11 J
liues.

Among a small collection of fossils from Texas, snbmitted to my examina-
tion by Professor S. B. Buckley, there is a specimen of an npper molar tooth
of a horse of peculiar character, represented in Fig. 18, Plate XXXIII.
The exact locality from whence the specimen was obtained is unknown.
The tooth is apparently a fourth or fifth of the series, and is only sufticiently
worn to exhibit the course of the enamel layers on the triturating surface.
The tooth is longer than in the domestic horse, and is rather narrower than
usual in relation with its fore and aft diameter. The folding of the enamel
defining the median lakes of the triturating surface is as complex as in Equus
complicatus, but in a ditferent position. In the latter the folding is greatest
on the contiguous sides of the lakes, as seen in Figs. 11 and 14, but in the
tooth under consideration the contiguous sides of the lakes are less .folded
than usual even in the domestic horse, while the enamel border at the inner
sides of the lakes is folded in an unusual degree. Further, the broad inner
peninsular fold of the triturating surface, which in the domestic horse and
other known species has a simple oval, elliptical, or reniform outline, in this
specimen is of extreme width, narrow, and folded at the extremities. The
width of this inner fold or column is uniform throughout the length of the
crown.

The length of the crown of this tooth, without the fangs, in the entire con-
dition has been upward of 4 inches. Its fore and aft diameter at the trit-
urating surface is 16 lines; its transverse diameter at the middle of the same
is 1 inch.

Fig. 19, Plate XXXIII, represents a fragment of an ii|)per molar sub-
mitted to my examination by Professor J. S. Newberry. It was obtained
from the lignite-beds of Shoalwater Bay, Washington Territory. It presents
nothing which distinguishes it from the corresponding part of the molars
of the domestic horse.

The length of the crown externally is 2f inches, and the fore and aft
diameter of the trituratin"; surface is 14 lines.

247

HIPPARION.

A small collection of fossils, submitted to my examination l)y Professor S.
B Buckley, mainly consist of equine remains, of wliich the determination is
uncertain and the near relations obscure. Most of them were obtained in
Washington County, Texas, a few in the contiguous county of Bastrop, and
several others in Navarro County. They were usually Ibund in digging wells,
at the depth of from 25 to 30 feet, imbedded in a rocky stratum. Most of
the specimens are free troui matrix, but several have attached portions of a
hard arenaceous limestone. From the character of the fossils, I suppose the
formation to be of contemporaneous age with that which has been called Plio-
cene Tertiary of the Niobrara River, Nebraska, Little White River, Dakota,
and that noticed in the preceding pages of the Sweetwater River, Wyoming.

Fig. 14, Plate XX, represents a specimen labeled as having been obtained
from an ossiferous rock at a depth of 25 feet, in Washington County, Texas.
It is a last upper molar of a small equine animal, and is moderately worn'
away at the triturating surface. It is strongly curved, and is nearly twice the
length antero-externally that it is postero-internally. In the isolation of the
antero-internai column from the antero-median column, as seen on the triturat-
ing surface, it accords with the character of Hipparion. It sufficiently re-
sembles in its relative proportions, and the complexity of arrangement of its
enamel-folds, the fragment of a tooth, represented in Fig. 17, Plate XVIII,
of the Extinct Mammalian Fauna of Dakota, &c., to belong to the same species.
The latter specimen was also obtained in AVashington County, Texas, and has
been referred to Hipparion speciosum, a species originally proposed from
specimens discovered at Bijou Hill, Dakota, and represented in Figs. 1(1, LS
and 19 of the work just indicated.

The measurements of the specimen are as follows:

Lines.

Length of crown anfero-externally H^

Length of crowu postero-internally ^h.

Breadth of crown antei'o-posteriorly ^k

Breadth of crown transversely - ^4

Another specimen, consisting of the middle portion of an upper molar, from
its proportions and the folding of the enamel lakes of the triturating surfece,
is supposed to belong to the same species. It was obtained in Navarro
County, Texas.

•248

Fig. 15 represents a specimen found in associaliuii witii that oC Uic jire-
vitins figure of" the same plate. It appears to be a tiiird or fourth up|)er
molar, ami, IVom the size and arrangement of enamel on the triturating sur-
liice, might be supposed to belong to the same animal as the former speci-
mens. In the proportions of the tooth it resembles those of Merychippus
more than it does those of Hipparion. The crown is quite short, and exhibits
a considerable degree of curvature. It is al^out 2 lines long on the inner side,
iind three times that length on the outer side. On the triturating surface the
antero-internal column appears as an elliptical ring, as in Hipparion, Ijut it
exhibits a pointed process indicative of continuity at a later period with the
antero-median column, as in Protohippus and Merychippus. The tortuous
enamel-line on the inner part of the triturating surface presents no median
fold directed toward the elliptical ring, as is the case also in the fourtii molar
of Protohij^ius, as seen in Fig. 2, Plate XVII, of the Extinct Mammaruiu
Fauna of Dakota, &c.

The antero-pqsterior diameter of the tooth is Tjj Hues, and its transverse
diameter 8.^ lines.

Another specimen, consisting of a mutilated, unworn molar, from its pio-
p(jrtions, is supposed to Ijelong to the same species as the former. It was
obtained at a depth of 30 feet from the surface in Washington County, Texas.
The crown internally is 5.J lines long, and has measured externally about 10
lines. Its breadth is 9 lines, and its transverse diameter has been but little
less.

PR(JTOIIIPPUS (?) s. MERYCHIPPUS?

Among the Texan collection of fossils there are several which are suspected
to belong to one or other of the equine genera above named.

Fig. IG, Plate XX, represents a specimen obtained from a well, at a dciith
of 32 feet, at Independence, Washington County, Texas. It is an upper
molar, apparently the second or third of the series of the usual complement
of six large teeth in equine animals. In its proportions it would appear to
belong to the genus Merychippus rather than Protohippus. The crown is
from 3J to 4 lines in length on the inner side, and from 7 to 8 lines on the
outer side. The median enamel lakes of the triturating surface are of simple
character, and widely gaping, apparently indicating but comparatively little
wear, notwitiistanding the shortness of the crown. In the appearance of the
triturating surface it resembles more the teeth of Piotoliippus 'peiditus, as

249

represented in Fig. 2, Plate XVII, of llie Extinct Mammalian Fauna of
Dakota, &c., than it does those of Merychippus, represented in Figs. 5 and 9 of
the same plate. On the other hand, it bears a near resemblance to the teeth
from Little White River, Dakota, represented in Fig. 1, Plate XXVII, of the
work just quoted, which were supposed to pertain to Merychippus mirahUis.

Another specimen, from Bastrop County, Texas, consists of an upper molar
with the portion internal to the median enamel lakes broken away. It is
rather smaller than the preceding, and would ai)pear to hold the relation with
it in the series of a fourth or fifth molar.

A third specimen, accompanied l)y a label in the handwriting of Dr. Shu-
mard, is marked ("Eocene,) Trinity River, Navarro County, Texas." It is a
lower molar, represented in Fig. 20, Plate XX, and may perhaps lielong to
the same species as the preceding.

The measurements of the specimens are as follows:

Lines.

Bi-eadth of the second upper molar 9|

Width of the secoud upper mokxr IQi

Breadth of the fourth upper molar ' S

Breadth of the lower molar 9

Width of the lower molar 53

Fig. 17 represents a specimen found in association with those of Figs. 14,
15, at a depth of 25 feet, in Washington County, Texas. It is an upper
molar of the right side, probably the fourth of the series. It is but moder-
ately worn, and is imperfect at the back inner corner. In its proportions and
degree of curvature it agrees with the teeth of Protohippus. In size and
arrangement of the enamel it approaches in character some of those referred
to Protohijypus placidus, represented in Figs. 39 to 48, Plate XVIII, of the
Extinct Mammalian Fauna of Dakota, &c.

The measurements of the specimen are as follows :

Lines.

Length on inner side 8

Length at antero-external corner lli

Breadth of triturating surface 7i

Transverse diameter of surface 7

Fig. 18 of the same plate represents a specimen from '"Little's Well,'" 30
feet in depth from the surface, in Bastrop County, Texas. It is a iirst upper
molar, and is sufKciently like the former to belong to the .same species. It
32 G

250

also resembles the corresponding toolli of Fii^f. 6, Plate XXVII, of the Ex-
tinct Mammalian Fauna of Dakota, &c., sufficiently to pertain to the same
species. This specimen was obtained on Little White River, Dakota, and
was referred to Protohiiipus placidus. The proportions of the former are the
same, but, being more worn, it is shorter, and appears larger at the triturating
surface. At the same stage of abrasion they would even bear a greater
resemblance to each other, as the open fold on the posterior part of the Little
White River specimen, in a more worn condition, would then form an islet on
the triturating surface, as in the Texas specimen.

The measurements of the specimen, in comparison witii those of the Little
White River specimen, are as follows:

Texas
specimen.

Dakota
specimen.

Length of crown at tbe antero-internal column..
Length of crown at the postero-external cohiinn .

Breadth of crown at the triturating surface

Width of crown at the triturating surface

Lines.

6
10

Lines.
S

The Museum of the Smithsonian Institution contains several specimens of
teeth apparently of ProtoMppus perdilus and Meryckippus mirabUis, obtained
by Mr. Clarence King in Utah.

AXCHITHERIUM.

AnCHITHERIUM (?) AUSTRALE.

Among the Texan collection of fossils there is a specimen of peculiar
character rejn-esented in Fig. 19, Plate XX. It was tbund in association with
that of Fig. 16, of the same plate, in Washington County, Texas. It is the
first of the series of six large upper molars as existing in equine animals, but
exhibits in front the impress of a premolar larger than usual in members of
the order. The specimen is broken at its outer part, but the remainder
is nearly as characteristic as if the whole were complete. The crown is so
worn away that the dentine is continuous upon all the constituent lobes. An
olilique valley extends from the inner side and ends in a foot-like expansion
near the center of the triturating surface, and l)ack of the center there re-
mains a crescentic enamel lake.

2.51

The tootli i.s devoid of" eoinentuni, and resembles in its constitution the cor-
responding one of Anchitherium nearer than it does that of other known
equine animals. The inner and intermediate lol)es appear somewhat fuller
than in Anchitherium, and the intermediate spaces narrower and less con-
vergent at bottom.

It maj' perhaps belong to Anchippus, founded on an imperfect tooth from
the same locality, and represented in Fig. 13, Plate XXI, of the Extinct
Mammalian Fauna of Dakota, &c. It presents important peculiarities, l)ut
these may depend on the difierence of position of the tooth in the series.
There is, however, one feature in the tooth of Anchippus which is absent in
the specimen under consideration, rendering it probable that the teeth per-
tain to different genera: The feature to which I allude consists of a con-
spicuous fold or offset from the postero-median lobe projecting into the oljlique
valley of the crown toward the antero-median fold. In Parahippus the same
fold exists in a more complex condition.

The tooth in question likewise resembles that represented in Fig. 11, Plate
XXI, of the work above quoted, as characteristic of the genus Hypohippus,
nearly as much as it does those of Anchitherium, and may, perhaps, belong
to a smaller species of the former.

In the uncertainty as to the nearer generic relationship of the specimen it
may be regarded as indicative of a species of Anchitherium with the name
given at the head of the chapter. Tiie species was about as large as the
Anchitherium aurelianense of the Eocene Tertiary deposits of France.

The estimated size of the tooth is 11 lines in diameter antero-posteriorly
and nearly the same measurement transversely.

Anchitherium agreste.

During Professor Hayden's exploration in Montana, he discovered several
fossil jaw-fragments of a species of Anchitherium. They were found in asso-
ciation with a Helix, partially imbedded in an indurated, gray, arenaceous
marl, and were derived from a lacustrine Tertiary deposit on Red Rock
Creek, one of the head Ijranches of the Jefferson Fork of the Missouri
River.

The jaw-specimens belonged to a species considerably larger than the
Anchitherium Bairdi of the Miocene Tertiary of White River, Dakota, and
approached in size (lu,^ A. aurelianense of the Pliocene Tertiary of France.

252

The teetli in the specimens, as represented in Figs. IG, 17, Plate VII, are
considerably worn, but retain their anatomical characters snfHciently to show
that they are identical in form with those of the two species just named.
They nearly accord in size \\'ith the mutilated upper molar, represented in
Fig 5, Plate II, from Oregon,' referred to Anchitherium Condom. In the doubt
whether the latter is really a true species of the genus in which it has been
placed, the lower-jaw fragments in cpiestion are regarded as representino- a
species with the name heading the chajiter.

Measurements from the specimens are as follows:

Lilies.

Space occupied bj' tbe back four molars 34

Space occupied by the back three molars 27

Fore and aft diameter of last premolar .... , S

Transverse diameter of last premolar G4

Fore aud aft diameter of first molar 73

Transverse diameter of first molar 7

Fore and aft diameter of last molar 11

Ti'ausverse diameter of last molar 5a

Anchitherium (?) .

In digging a well at Antelope, Nebraska, in the summer of 1868, at the
depth of 60 feet a stratum was found which was stated to be remarkable
for the number of fossil-bones it contained. The relative age of the stratum
has not yet been ascertained, but from the character of the fossils it is sus-
pected to be contemporary with the Mauvaises Terres formation of White
River, Dakota, or perhaps with the later formation of the Niobrara River,
Nebraska. From among the specimens collected at the time, my friend Dr.
John L. Le Conte obtained a coronary bone of a small equine animal, which he
sent to me- for examination .

The specimen was exhibited to the Academy of Natural Sciences, and is
noticed in its Proceedings for August, 1868. Subsequently, some remains,
apparently of tlie same animal, from the same locality were described by
Professor Marsh in the American Journal of Sciences for October, 1868, and
referred by him to a diminutive horse with the name of Equus parmilus.

The specimen of the coronary bone is represented in Fig. 23, Plate XX.
It is only a little over half the length and is considerably less than half the
breadth of the corresponding bone of the horse, so that it indicates an animal
of little more than half its height and of more slender proportions. Its
size would about accord with Anchitherhan Bairdi of the White River
Tertiary formation of Dakota.

253
The nieasurciiiLUits of the specimen nre as follows:

Lill(^S.

Lcngtli ill the axis 9

Breadth at tTie upper extremity !)

Thiclvuess at the upper extremity (>

Breadth at the lower extremity 8

Order Ruminantia.

BISON.

Bison latifeons.

Remains of large oxen which were contemporaneous witli the American
mastodon have been discovered in several parts of North America. They
have been referred to several extinct species, but the materials have been too
incomplete to determine the question with any degree of satisfaction whether
they pertain to more than one. The fossils indicate individuals very greatly
diflfering in size, but the difference is perhaps sexual rather than sjjecific:
The more robust specimens probably belonged to males, and the smaller
ones to females.

The most complete specimen which the author has had the opportunity of
examining is the cranium, retaining the horn-cores, represented in Figs. 4, 5,
Plate XXVIII, one-fifth the natural size. It was discovered by Mr. Calvin
Brown and his son Wilfred, of San Francisco, California, while engaged as
engineers in the construction of the Spring Valley water-works of that city,
and by these gentlemen was presented to the Academy ot Natural Sciences of
Philadelphia. Mr. Calvin Brown informs me that tiie cranium was found
in a bed of blue clay, 21 feet below the surface, in Pilarcitos Valley.

The specimen resembles the corresponding part of the skull of the living
buffalo {Bison mnericanus) so closely that it will be unnecessary to describe' it
in detail. Besides being larger, the horn-cores are especially dispropor-
tionately larger, and are more transverse in their direction, or are less inclined
backward. The occiput appears proportionately wider and lower from the
less degree of prominence of its summit. The latter is, however, ^\•ider,
and is more distinctly defined from the posterior occipital surface by the
rougher and more prominent protuberance of attachment for tlie nuchal
ligament. The occipital foramen is no larger than in the l)uffalo., and the
notch below, between the condyles, is more contracted. The Ibrelicad, near
its middle, is rather more protuberant than in the bnlfalo.

254

Comparative measurements of the fossil with the correspoudiug part of
the skull of a large buffalo are as follows :

Bison
latifrons.

Distance between tips of horn-cores

Distance between bases of born-cores

Circumference at bases of born-cores

Lengtb of born-core along lower curvature

Breadth of forehead where narrowest

Breadth of forehead at back of orbits

Length of forehead from occiput to fronto-nasal suture

Breadth of occiput

Depth of occiput

Breadth of condyles together

Transverse diameter of occipital foramen

Vertical diameter of occipital foramen

Distance between ends of paramastoid processes

Length of temporal fossa - -

Indies.
.36
15J
14
Uh
13^
16
13J
12A

Bison
americanus.

Inches.
26
12
11
12
11

10
10

5
2

The California collection of fossils, belonging to the cabinet of Wabash
College, Indiana, contains several specimens of teeth which I suppose to
belong to Bison latifrons. They were loaned to me for examination through
the kindness of Professor E. O. Hovey, and are represented in Figs. 6, 7, Plate
XXVIII. They consist of the second and third upper molars, and agree in
constitution with the corresponding teeth of the recent buffiilo, and in size
correlate with the skull above described and referred to B. latifrons.

The measurements of the specimens, in comparison with those of the
buffalo, are as follows :

Bison
latifrons.

Bison

americanus.

Secontl upper molar :

A iitorn-i^nsit'pririr diMTTiPtpr of t,rif,nrnt'iill<T' SUvfMfiP,

Lines.

18
13i

Lines.
15

Transverse diameter of triturating surface -

T'i'missv'prQfi flininptpr of orown iionr l"»nsp ■ - ^

lOa
123

Third upper molar :
Aiifpro-no<*tprior (liniiifteT of tritnratitisr surface

Transverse diameter of tritui^ating surftice

Transverse diameter of crown near base

255

An isolated iippcr secuiul molar of Biison laufrons^ found in association
with remains of Mastodon ainericanus and Equus major at Pittstown, on the
Susquehanna River, Luzerne County, Pennsylvania, is represented in Fig. S,
Plate XXVIII. It is considerably worn, the usual median internal fold of
the tooth, in a less worn condition, being seen in the specimen as an
oval islet.

The fore and aft diameter of the specimen is 16.j lines, and its transverse
diameter at the triturating surface I'/ lines.

A specimen of a last inferior molar of a Bison, represented in Fig. 4,
Plate XXXVII, and a metacarpal bone of the Megulonyx Jeffersoni,
presented to the Academy l)y Dr. Edward D. Kittoe, of Galena, were
obtained, together with some additional bones, from a crevice of the
lead-bearing rocks, at a depth of 130 feet from the surface, near
Elizabeth, Jo Daviess County, Illinois. The tooth is about the size of
that of the recent bulfalo, and may pertain to that species, though it is not
improbable it may have belonged to a small individual of Bison latifroiis.

The specimen is but little worn. The length of the crown at its fore part
is '2| inches ; its breadth 23 lines ; its thickness at the base anteriorly 10
lines ; and near the triturating surface 7 lines.

AUCHENIA.

AUCIIENIA HESTERNA.

In the Proceedings of the Academy of Natural Sciences for 1870, page
125, the writer described some fossil remains from California, submitted to
his inspection by Professor J. D. AVhitney. Among the fossils were several
which were attributed to a large extinct llama, with the name of Auchenia
californka. The specimens upon which the species was founded consisted
of a metacarpal l)one, the fragment.of another, the proximal end of a femur,
an acetabulum, and portions of a tiliia. The species indicated was much
larger than the camel, as the head of tlie femur is 3 inrlios in diameter, and
the metacarpal is 19 inches long, whereas the latter in the camel is but 13
inches long.

In the Philosophical Transactions of London for 1870, Professor Owen
has described some remains of a large extinct llama from Mexico, under the
name of Palauchcnia magna. This animal approximated in size the camel,
whereas the remains attributed to Auchenia californica much exceeded it.

Of the remains referred by Professor Owen to Palauchenia, there is a

256

series of" molar teeth described and figured from casts and photographs. The
teeth are considered as pertaining to the lower jaw, but from a view of the
figures I cannot avoid the suspicion that they really belong to the upper jaw.
In the form and proportions of the molars, but especially in the form, consti-
tution, and number of the premolars, the series appears to me to resemble
more the upper one of the camel and llama than it does the lower one. In
one respect one of the molars, the last of the series, approaches in character
the last lower molar of the camel and llama. • This is in the possession of a
fifth lobe, which is, however, much less well developed than in the latter
animals. If the view I have taken is not erroneous, Palauchenia, so far as
we know it from its remains, would not present sufficient distinctive char-
acter to be regarded as of a different genus from Auchenia.

Among the collection of fossils from California, belonging to the cabinet
of Wabash College, Indiana, tliere is a well-preserved series of lower molar
teeth, represented in Figs. 1, 2, Plate XXXVII. These, from their size and
constitution, would appear to belong to a species of llama exceeding in size
not only the existing llama, but also the camel and the Palauchenia.

The question at once arises whether these teeth belong to Auchenia cali-
fornica, Palauchenia magna, or to a third species.

The proportions of the bones upon which the former was founded indicate
an animal one-third larger than the camel, but the teeth above noticed might;
belong to an animal but little exceeding a large camel or the P. magna. If
the characters assigned to the latter as a genus are correct, it is clear that
the series- of teeth from California do not belong to the same animal, and tliey
then could only pertain to a small individual of Auchenia callfornica, or to
another species rather larger than the existing camel. Under the circum-
stances, until further light is thrown on the subject by the discovery of addi-
tional material, we may suppose that two large species of llama, perhaps"
exclusive of Palauchenia magna, were once inhabitants of the western por-
tion of the North American continent, contemporaneously with the Mastodon
americanus. One of these species, a third larger than tlie existing camel, is
the Auchenia californica ; the second, intermediate in size to the two latter,
may be named A. hesterna. .

The teeth in question indicate an animal which had arrived at .maturity.
While the first molar, which earliest acquired its functional position, is much
worn, the last molar has its fifth lobe unabraded, and the pi-emolar has but
partially lost its summit.

257

The molars sliow no cliaracteristic differences t'roni tliose of the llama and
eamel. The narro\\' told seen projecting outwardly in advance of the antero-
external lobe of the last molar, and in a less degree in the second molar, in
the llama, is nearly obsolete in the fossil.

The premolar presents some difference from the corresponding tooth *in
the llama. The crown is thickest, and is romided behind, and it narrows
lbr\\ard to the anterior subacute border, which is convex longitudinally, and
is thickened toward the bottom. The outer side is not impressed at the back
part, as in the llama, and is feebly impressed at the fore and upper part. The
inner side also is but moderately impressed along the middle, compared with
its condition in the llama. A deep enameled pit occupies the inner back part
of the crown, penetrating from the triturating surface, as in the latter. The
pit opens backward for a considerable portion of its depth, and is closed in
this position by apposition with the succeeding tooth.

The measurements of the teeth, in comparison with those of the camel
and llama, are as follows :

Fourtfi premolar:

* Breadth of crovcu where greatest

* Width of crown where greatest. .
Length of crown to origin of fangs.

■ First molar :
Breadth of triturating surface.
Width of triturating surface . .
Length of crown

Second molar:
Breadth of triturating surface. .
Width of triturating surface . . .
Width of crown where greatest.
Length of crown

Third molar :
Breadth of crown where greatest.
Width of crown where greatest . . .
Length of crown

Aucheuia
hesterna.

Lilies.

lOi

20"

20
10

Aucbonia
lauia.

Camel.

Lines.

•J.-i

Lilies.

5 .

h.L

* For brevity I bave iised breadtb for tbo antero-posterior diameter, and width for tlio trausverso

diameter.

33 cf

258

The length of the sei'ies of lower inoLais and premolars together, in the
clitFerent species, is as follows :

Lines.

LcTigtU of tbe series iu the llama 32

Length of the series in the camel C(i

Length of the series iu the Auchenia hesterna 84

Accompanying the inferior molar specimens from California there is a
specimen of an upper molar represented in Fig. 3, Plate XXXVII, which,
from its constitution and size, is supposed to belong to the same species, if
not the same individual.

It is a first or second true molar of the left side, and closely resembles tlie
corresponding teeth of the llama.

Its comparative measurements are as follows :

Second upper molar.

Llama.

Camel.

Auchenia
besterua.

Palauchenia
magna.*

Breadth of the triturating surface

Lines.

Lines.
20
11
13
10

Lines.
23J
12

Lilies.
21

Width of the triturating surface

Width of crown near base

11^

Length of crowu

lOJ

"Professor Owen's measurements giveu as those of the secoml lower molar.

PROCAMELUS.

The genus Procamelus, or Protocamelus, was originally named from remains
discovered by Professor Hayden, in the Tertiary sands of the Niobrara Eiver,
Nebraska. Three species were indicated from tlie locality under the names
of Procamelus rohustus, P. occidentalism and P. gracilis. The specimens show
that Procamelus possessed a series of four premolars and three molars to the
lower jaw, from which we may infer an equal number to the ujiper jaw. The
molars and last premolar have the same form as those of the camel.

Among the Texan collection of fossils, loaned by Professor Buckley, there
is a specimen of a tooth supposed to belong to Procamelus. It is repre-
sented in Fig. 21, Plate XX, and was found in association with the equine
teeth before described, and represented in Figs. 14, 15, and 17 of the same
plate. It is a first or second upper molar, and sufficiently resembles the
corresjiftnding tooth of P. occidentalism as we may suppose it would appear in

259

the same stage of wear, as to render it probable tliat it may Ijelong to. the
same species.

The tooth is much worn, leaving two narrow crcscentic enamel pits in the
middle of the triturating suriace. No trace of an internal column or tubercle
e.xists in the interval internally of the inner lobes of the crown.

The specimen measures 11 lines antero-posteriorly, and nearly the same
extent transversely.

Fig. 22 represents an astragalus found in association with the molar tooth
just described, and probably belonging to the same animal. It has nearly
tlie size and form of those of the common deer, but is proportionately a little
longer and narrower.

Another specimen in the same collection consists of a cubo-navicular bone
of a ruminant a fourth smaller than the common deer. It was found in asso-
ciation with the equine tooth above described, and represented in Fig. 16,
Plate XX.

An additional specimen consists of a last lumbar vertelri'a, a])parently of a
ruminant. It was obtained in Washington County, at a de[)th of 30 feet,
from a hard arenaceous limestone. It is white in color, crushed downward,
and has a portion of the matrix adherent. The vertebra has nearly the size
and form of the corresponding bone of the camel, and tnay have pertained to
the largest species of Procamelus, named P. rohustus.

Procamelus virginiensis.

I may here indicate the recent discovery of some remains, apparently of a
species of Procamelus, in the Miocenj3 Tertiary formation of Virginia, the
first which have yet been noticed of the family in any locality east of the
Mississippi River.

Mr. C. M. Smith, of Richmond, Virginia, while engaged in excavating a
tunnel beneath the city, discovered a number of bones and teeth, which he
has loaned to me for investigation. They were found imbedded in blue clay
containing numerous infusorial remains, among which the beautiful frustules
of a Coscinodiscus are especially conspicuous. The fossil-bones mainly
consist of those of cetaceans and fishes, but among them are a few of
land-animals, and also a portion of a humerus of a Inrd. The forma-
tion from which the fossils were derived is proliably an estuary deposit of
Miocene age. Among the fossils there are several tcetli, which arc sup-

260

l)ose<l to belong to a species of Procainelus. The spcciiiieiis, consisting of a
last premolar, aud the first and last molars of the lower jaw, are represented
in Figs. 26 to 29, Plate XXVII. The teeth have the same form and consti-
tution as those of the western species of Procamelus above named, and they
appear to indicate an additional species, which was about the size of the ex-
isting llania, and intermediate in size to P. occldcntaHs and P. graciUs
The measurements of the teeth are as follows :

LiiR's.

Autero-posterior diameter of last premolar 7

Transverse diameter of last jiremolar 4

Anteroposterior diameter of first molar 7;^-

Transverse diameter of first molar (]

Anteroposterior diameter of last molar ll'i

Transverse diameter of last molar 0

MEGxVLOMERYX.
Megalomeryx niobrarensis (?)

The genus to which the above name was applied has not been determined
by ])()sitive characters, and may prove not to be distinct from Procamelus.
It was i)roposed on two specimens of teeth of a large ruminant, apparently
of the camel family, discovered by Professor Hayden in the Pliocene Tertiary
sands of the Niobrara River, Nebraska. The teeth, both lower molars, are
described in the " E.\tinct Mammalia of Dakota and Nebraska,'' page 161, and
are represented in Figs. 12-14, Plate XIV, of tliat work.

•A similar tooth was submitted to my examination, by Professor J. D. Whit-
ney, fi-om the Pliocene Tertiary of Tuolumne County, California.

Figs. 24, 25, Plate XXVII, represent a mutilated lower molar, apparently
(d'the same species. This was found in L'Eau qui Court County, in Northern
Nebraska, and was presented to Swarthmore College by George S. Truman.

0 H E L 0 N I A .

EMYS.

Emys petrolei.

An extinct species thus named is indicated l)y a number of fragments of
several turtle-shells, which were found in association with remains of Masto-
don, Megalonyx, Equus, Tnicifrlis fafalis, &c., in Hardin County, Texas.
They were ol^tained I'roin a stratum of clay beneath a bed of bitumen, and.

261

lik(! must of IIr' otliLT i'ostiiLs aecoinpauyiiig them, are tliuroiighl}- saliiratcd
with bitumen.

Tiie most characteristic specimens consist of two isolated cpisterna, repre-
sented in Fig. 7, Plate IX. They indicate an animal al)()ut tin? size of the
recent Emys scabra of the Southern States, but the hones are proportionately
more robust tlian in that species. They abruptly project in advance of the
lateral grooves defining the gular scutes, antl are squarely Iruneate'd. Tiie
upper gular surface is nearly square, and slopes forward to an acute edij:e.
In one specimen it is wider fore and aft than transversely; in the other rather
less. Behind the gular surface, the bone is deeply hollowed into a concavity.

The measurenients of the specimens are as follows :

Wkltli of episternal at the front bonlor ... I 10

Length of internal border 11

Leugtli of po.stero-lateral border 12

Greatest thickness of tlie bone j 5J

A hyposternal bone about the middle is 28 lines fore and aft, 26 lines wide
behind the inguinal notch, and half an inch where thickest internally.

The fore part of a nuchal plate of the carapace resembles the corres|)on(l-
ing portion in Emys scabra, but is more deeply indented. Its width in IVont
is an inch; the length of its median ridge is 10^ lines; and its thickness where
greatest is half an inch.

FISHES.

The following species of extinct fishes were first described by the writer
in the Proceedings of the Academy of Natural Sciences of Philadelpliia iiir
June, 1870. Tiie specimens were borrowed for my examination from a
gentleman ot New York, by my friend Mr. George N. Lawrence, of the
same city. The locality of the specimens was not ascertained other than
that they came from the Rocky Mountains. They were accompanied with
some shells, evidently of the later Tertiary period, and also with a coronary
bone, apparently of Equus exceisiis. The fish-rcmains consisted of eight
detached i)haryngeal bones of a cyprinoid. and a single dermal bone of a ray.

Subsequently, while a notice of these fossils was in press, the writer
received from Professor Hayden a pharyngeal bone of the same species and
ap[>earauce as the Ibrmer, which was labeled "Castle Creek, Idaho."

2(32

More recently, Prulbssor J. S. Newberry sent to me a small collection of
fossils, among which were seven additional specimens of pharyngeal Itones,
identical in appearance with the former, which were stated to have been
fonnd at Castle Creek, Idaho.

Later, Professor Cope described, in the Proceedings of the American
Philosophical Society, a number of species and genera of extinct cyprinoid
fishes from Catharine's Creek, Idaho. Among these he indicates the same
species as that to which the above-mentioned pharyngeals have been
attril)nted, and which have been referred to a previously undescribed genus,
as follows :

Family Cyprinidce.
MYLOCYPRINUS.

MvLOCYPfilNUS EOBUSrUS.

The specimens, consisting of detached pharyngeal bones with teeth, from
which the genus and species were oi'iginally described, were all imperfect.
Having attempted the description without a previous comparison with the
corresponding bones of a recent cyprinoid, I find I have been so careless as
to have described them in an inverted position. The specimens later received
are better preserved, and among them are five complete ones. All the
specimens together exhibit such a variety in size and detail as to lead one to
suspect they may- represent sevei'al different species, though I view them as
belonging to a single one, the diiferences being, as I suppose, mainly due to
a difference of age. Six specimens, from Professor Newberry's collection,
are represented, of the natural size, in Figs. 11 to 17, Plate XVII, all of them,
excepting Fig. 16, being views beneath with the back part directed upward.
Fig. IG represents an inner view, exhibiting the masticatory surfaces of the
teeth.

The principal i-ow of teeth consisted of five, as may be seen by the organs
themselves and their remains in Figs. 11 to 14, inclusive. They are all of
the true masticatory type, and are directed inwardly, opposed to those of th(;
other side. Tiic first and last of the series are the smallest, and the inter-
mediate ones are comparatively large.

In the smallest specimens, and the youngest, as I suppose them to be, the
second tooth is the largest, and from this they .successively decrease in size

263

to the last, as seen in Fig. 13. In tlie largest and oldest specimens, tiie in-
termediate three teeth are nearly equal in size, as seen in Figs. 16, 17. In
the specimens of intermediate size and age we notice some irregularity, hut
generally a disposition to increasing uniformity of size in the corresponding
teeth.

The first tooth is directed backward toward those behind; the otliers are
parallel in their direction inwardly.

The crown of the terminal teeth is more mammillary than in the interme-
diate ones, in which it is oval with the longer diameter directed from above
downward, and the short diameter fore and aft. The masticating surface of the
teeth is broad, oval, moderately convex, sometimes nearly flat, and usually
slightly depressed at the middle or at the center. The crowns resemble
strikingly those of worn human premolars, and are covered by tliick, smooth
^nameloid substance.

The teeth are supported on strong bony columns as long as the crowns
They project from the lower ramus of the pharyngeal below tlie position of
the upper or postei'ior ramus. The last of the series projects backward and
inward from the conjunction of the two branches, as usual in cyprinoids.

In the older specimens, it would appear that the first tooth of the series
was after a certain time not replaced.

Most of the specimens present evidences of the existence of two minute
teeth forming a secontl row above the principal one.

The pharyngeal bones, in accordance with the strong crushing teeth they
sustain, are stronger than usual in the ordinary living carp-like fishes.

The pharyngeal bone is widest opposite the larger teeth. The oblique
surface directed forward and outward exhibits the usual deep hollows extend-
ing to the bases of the teeth, or through the bone in some cases when the
latter are absent or shed. The posterior and inferior surfaces are flat, and
transversely striated, or, in the older ones, more or less strongly ridged. The
anterior border is vertically concave. The external border, acute below and
obtuse behind, is unusually thick. The inner border, extending backward
beyond the conjunction of the two branches of the bone, is that wliich sus-
tains the teeth.

The upper or posterior ranuis is- comparatively short, bent forward and
inward, and ends in a p(jint by which it was suspended from tlie occiput.
The extremity of (he louiT or anterior ramus, extending in advance of the

264

teeth, ends in a triangular process vvitli a lozeuge-like articular surface Ibr
symphysial attachment with the bone of the opposite side.
Measurements derived from seven specimens are as follows:

. Measurements.

Spec. 1.

Spec. 2.

Spec. 3.

Spec. 4.

Spec. 5.

Spec. 6.

Spec. 7.

Leiigtli of .series of five teeth , . . .

Lines.

Littcs.

Lines.

11
2i

^
2

Lines.

2i
2
2
1*

Lines.

Leugtli of series of four teetbj exclud-

15*

12
10

Length of series of intermediate three
teeth

Leugth of series of anterior three teeth.

Lone" diameter of crown of first tooth . .

Long diameterof crown of second tooth.
Short diameter of crown of second tooth.
Long diameter of crown of third tooth .
Short diameter of crown of third tooth .
Long diameter of crown of fourth tooth.

5
3J

3
3

20*

12.J

22
4

2.r

3"
0

IS
li
•14

Short diameterof crown of fourth tooth.

Long diameter of crown of tifth tooth .

Short diameter of crown of fifth tooth .

Length of lower branch from back of
iiharvniieal.

24*

17*
14

lU
10

11
9

14
10

lOJ

Depth of upijer branch to bottom of
pliaryngeal

Widtli of pharj'ngeal iuferiorly

Estim.ated.

Family Raice.

ONCOBATIS.

Oncobatis pentagonus.

An extinct ray, before alluded to, is indicated by a single dermal Ijone, of
which two views are given, of the natural size, in Figs. 18, 19, Plate XVII.
The bone has a pentagonal outline with curved margins, with the under or
inner surface strongly convex and smooth. The upper or free surface presents
five sloping planes more or less well defined by prominent borders. Less
lliaii half the extent of the external surface at the center is occupied by an
areola of thin enameloid substance which is smooth and shining nnd marked
with concentric lines. The summit of the lione, in the center of the areola,
l)rojects as a point of harder and more translucent osseous substance.

The measurements of the specimen are as follows:

Lines.

Greater diameter of the dermal bone , IG

Shorter diameter of the dermal bone 15

Thickness from summit 8

The many more fossil-remains of fishes from the Tertiary formation of
Idaho, described by Professor Cope, he attributes to two additional species
of Mylocyprinus, seven species of four other genera of Cyprinidse, and a
species of Salmonidse. Fossil-shells described by Mr. Meek from the same
formation, as well as the cyprinoid fishes, indicate a fresh-water deposit. The
presence of a ray may probably indicate an easy communication with salt
water.

34 G

DESCRIPTION OF REMAINS OF REPTILES AND FISHES FROM
THE CRETACEOUS FORMATIONS OF THE INTERIOR OF THE
UNITED STATES.

The Cretaceous formation in the interior of the United States covers an
area reaching southerly into Texas, and extending over a large portion of tiie
eastern slope of the Rocky Mountains, northerly along the region of the
Upper Missouri River to its sources. Exposed to viisw over a great extent
of this area, a still larger portion underlies the vast Tertiary deposits of the
country, Its thickness ranges from 800 to 2,500 feet, and it consists of
various colored strata of indurated clays and sandstones, and indurated marls
and limestones. So far as known, most of them are of marine origin, and
contain an abundance of characteristic fossils. Some of the strata con-
tain remains of terrestrial plants, proving that the country in the vicinity of
the great Cretaceous seas was clothed with forests resembling, in the generic
characters of the trees, the forests of our own time. Species of sweet-gum,
poplar, willow, biroh, beech, oak, sassafras, tulip-tree, magnolia, maple, and
others have been described from the fossils. With such a vegetation we
would expect the contemporaneous existence of some forms of mammalian
life, but as yet, in these as well as in other Cretaceous deposits of the world,
no remains of mammals have beeu discovered. We are, however, still on
the lookout for some lacustrine or river deposit of the Cretaceous era which
perhaps will reveal early forms of mammals — forms which may more nearly
relate the mammal with the reptile than any now known to us.

Remains of birds have been found in the Cretaceous formation of Kansas,
and have been described by Professor Marsh. Two genera indicated by him
under the names of Ichthyornis and Apatornis are the most I'emarkable of
their kind, and may be viewed as tbe most interesting and important paleoii-
tological discovery yet made in the West. They have biconcave vertebivne,
and the j^ws are furnished with teeth. Like the Archeeopteryx of the Solen-
hofen limestone, they make the relationship of birds to reptiles much nearer
than appears among existing forms.

267

111 remains of reptiles and fishes the western Cretaceous formation abounds.
Many of these have been described by Professor Cope and Professor Marsh.
Araoiiir the reptiles are some of the largest and most wonderful of their kind,
represented by great turtles allied to Atlantoclielys ; numerous species of
Mosasaurus and closely related genera ; the Polycotylus and the long-necked
Discosaurus allied to Plesiosaurus ; and Pterodactyls, with an enormous
expanse of wings.

The following pages contain descriptions of remains of reptiles and fislies
which have come under tlie observation of the author mainly from the west-
ern Cretaceous deposits. A few of the remains are doubtful as to the forma-
tion from which they have been derived, but are believed to be Cretaceous
fossils. As intimately related with the western Cretaceous fossils, descrip-
tions of a few others are included from eastern localities.

Most of the fossils were submitted to the examination of tlie author by the
Smithsonian Institution, and form part of a collection from the Smoky Hill
River, Kansas, and from the Indian Territory, presented to the Army Medical
Museum of Washington by Di-. George M. Sternberg, United States Army.
Others from the Smithsonian Institution were collected in the vicinity of
Fort McRae, New Mexico, and were presented to the Army Medical Museum
by Dr. W. B. Lyon, United States Army. Many of the fossils were collected
during the explorations of Professor Hayden. The remainder form part of
the Museum of the Acadeiny of Natural Sciences and Swarthmore College,
or have been contributed by Dr. William Spillman, Dr. John L. Leconte,
Professor George H. Cooke, William M. Gabb, George II. Truman, and
others.

REPTILES.

Order Dinosauria.
POICILOPLEURON.

POICILOPLEUKON VALENS.

During Professor Hayden's expedition of 1869, a fossil was given to him
as a " petrified horse-hoof" The specimen was found in Middle Park, Col-
orado, and according to Professor Hayden was probably derived from a forma-
tion of Cretaceous age. Similar specimens were reported not to be uncommon,
and were known as above designated. Indeed the writer has seen a second
specimen, which was also called a fossil horse-hoof, but unfortunately liis
notes in relation to it have been mii-laid.

2G8

The fossil in question consists of one-half of a vertebral body as repre-
sented in Figs. IG to 18, Plate XV. When resting upon the articular face,
it is not surprising that it should have been taken tor a '' petrified horse-
"hoof" by those not conversant with anatomy.

The vertebral body in its entire condition would resemble in form those of
Megalosaurus, and in shape and other characters resembles those of Poicilo-
pleuron Bucklandi. This is an extinct reptile, from the Oolitic formation of
Caen, Normandy, described by M. Deslonchamps ; and remains apparently
of the same animal, from the Wealden formation of Tilgate, England, have
been noticed by Professor Owen. It has been viewed as a crocodilian, and
is estimated to have been about 25 feet in length.

The Colorado fossil would indicate an animal approximating 40 feet in
length.

One of the most remarkable characters of Poicilopleuron is the presence
of a large medullaiy cavity within the bodies of the vertebrae, as well as in
the long bones of the limbs. Among living animals I know of a similar con-
dition in the vertebrae of none except in the caudals of the ox. This curious
"feature is a striking one in the Colorado fossil, as represented in Fig. 18.
The lower two-thirds of the body appear occupied hy a large cavity, crossed
by a few osseous trabeculse. The cavity is bomided by a thick lateral and
inferior wall of compact substance, resembling that of the shaft of the long
bones of most mammals. The wall is about 2 lines thick, and thins away
at the upper part of the body where this is occupied by the ordinary spongy
substance. The latter extends into the abutments of the neural arch, and is
here more dense in character. The cavernons structure of the fossil is filled
with crystalline calcite.

The estimated length of the vertebral body is about G inches. At the sides
and beneath it is much constricted or narrowed toward the middle. The
transverse section approaching the latter position is vertically ovoid, with the
lower and narrower end forming an acute angle.

The articular end of the specimen, Fig. 16, is moderately depressed its
greater extent, most so above and becoming more superficial below. Its
upper border overhangs the deepest portion of the surface ; the lateral bor-
ders are obtusely rounded, and widen below in a strongly convex ledge, prob-
ably for the accommodation of a chevron bone. The bi'eadth of the articular
surface is nearly 4 inches ; Its vertical extent a little over that measurement.

270

The abuliuents of the iieurul arch are tirraly co-ositied wilh the body, but
tlieir SLitiiral connection is plainly visible. Just l)elow the suture, the side of
the body presents a concavity. The beginning of a groove or narrow con-
cavity is also seen extending forward beneath the body. The lateral surfaces
of tlie specimen are smooth, excepting near the everted articular border of
(he body, where they are roughened for the firmer attachment ot ligaments.

Poicilopleuron was probably a semi-aquatic Dinosaurian, an animal equally
capalile of living on land or in water, and perhaps spending most of its time
on shores or in marshes. Whether the cavernous structure- of its skeleton
was related to pneumatic functions, as in birds, flying reptiles, and some
others, or whether it was only occupied with ordinary marrow, is a question
that appears uncei'tain while our knowledge of the skeleton itself is so
incomplete.

Order Clielonia.

Among Dr. Sternberg's collection of fossils from the Smoky Hill River,
Kansas, there are several which appear to be the limb-bones of a turtle.
Similar bones from the Cretaceous formal ion of New Jersey and Mississippi'
I formerly attributed to species of Mosasaurus, but the recent discoveries of
characteristic portions of the skeleton of this and allied animals, retaining
the limbs, have proved that view to be erroneous.

A huge turtle, represented" by the proximal extremity of a humerus ibund
in the green sand of New Jersey, was named by Professor Agassiz Atlan-
tochelys Mortoni. Professor Cope has described some remains of a species
nearly as large as the former, from Kansas, under the name of Protosfega
gig'is; and an arm-bone of a smaller turtle, from the Cretaceous formation
of Mississippi, he has referred to a species with the name of P. tuberosa.
Remains of a turtle, about the size of the Mississippi snapper, from Kansas,
he has attributed to another genus with the name of Cynocerciis incisus. The
specimens of limb-bones above mentioned, and represented in Figs. 17 to 21,
Plate XXXVI, are not large enough to pertain to the smallest of the three
species of Atlantochelys indicated, but would sufficiently relate in size with
the remains of Cynocercus incisus to belong to that animal.

The bones appear unusually flat, but this condition, in part at least, is due
to compression.

Fig. 17, Plate XXXVL represents the upper extremity of a luuncrus

270

extencling to the commencement of the distal expansion of the shaft. It
resembles nearly the corresponding })ortion of the humerus of the snapper
completely flattened, or a miniature of that of Atlantochelys in the same con-
dition. The greater tuberosity appears to spring from above the top of the
head externally, so that its upper anterior border looks like an extension of
the articular surfiice of the latter. A strong muscular impression is situated
upon the inner fore part of the shaft. The lesser tuberosity projects poste-
riorly, and ends in a thick, roughened, convex surface.

The breadth of the specimen between the two tuberosities obliquely meas-
ures 33 lines ; the breadth of the shaft, where narrowest, is 10 lines.

Fig. 18, represents a complete femur, apparently from the same individual
as the former. As in the snapper and Trionyx, it is of proportionately less
breadth than the humerus. It is apparently much flattened by pressure, so
as to differ considerably from its exact original form. The trochanters appear
I'elatively to have been as well developed as in the snapper, and the distal
articulation may be supposed to have had nearly the same form.

The length of the femur is 64 inches. The breadth of the upper ex-
tremity is 20 lines, of the lower extremity 16 lines, and of the middle of
the shaft 7 lines.

Several additional bones accompanying the former appear to belong to the
shoulder of the same animal.

Fig. 19, represents what appears to be a portion of the left scapula with its
upper end and the prge-coracoid prolongation broken away. The specimen
appears distorted and flattened from its normal condition as the result of
pressure.

Fig. 20, represents what appears to be a portion of the coracoid bone of
the same side, also somewhat distorted by pressure.

Fig. 21, represents another bone-fragment, apparently from the same indi-
vidual, which I cannot determine to my own satisfaction. Like the other
specimens, it appears flattened from its normal condition.

Order Mosasauiia.

Large, extinct, marine saurians, most nearly ccHistructed as in Lacertilians,
but having limbs constructed as paddles for swimming. The relations of these
reptiles with the serpents, as suggested by Professor Cope, in his Synopsis of
the Extinct Batrachia, Reptilia, &c., have been much reduced by the subse-

271

quent discoveries of Professor Marsli ; and tlicy appear hardly sufficient to
justify the name of Pytlionomorplia.

Tlie remains of mosasauroid reptiles are comparatively aljundant in the
Cretaceous formation of the United States. The specimens collected have
formed the basis of a multitude of species and genera, the number of which
will probably be somewhat reduced on more careful study and comparison of
the materials.

In the description of the few mosasauroid remains which have been sub-
mitted to my examination, I have referred them to species for the most part
as recently named by Professor Marsh, who, with the rich materials in his
jjossession, has the best opportunity of determining their generic and specific
characters.

TYLOSAURUS.
Tylosaurus dyspelor.

Among the fossils submitted to my examination by the Smithsonian Insti-
tution, there are some bones of a large mosasauroid animal, collected by Dr.
W. B. Lyon, United States Army, in the vicinity of Fort McRae, New Mexico.
They consist of vertebra?, mostly more or less crushed and otherwise muti-
lated, and a few limb-bones, and were ol)tained from a stratum of soft, yel-
lowish chalk. Specimens from the same collection and skeleton were de-
scribed by Professor Cope, and referred to a species with the name of Liodon
dyspelor. This was subsequently referred to a genus, by Professor Marsh,
with the name of Rhinosaurus, which, being pre-occupied. Professor Cope
proposed that of Rhamphosaurus, and, as this also was previously approjiri-
ated, Professor Marsh has now proposed the name of Tylosaurus.

Of the specimens selected by me for examination half a dozen consist of
centra and parts of others of posterior dorsal vertebras, most of which are
remarkable for tha extent of compression they have undergone with little
appearance of fractures. They look as if they had been in a plastic condi-
tion, and in this state had been flattened from above downward.

In three of the specimens, consisting of posterior halves of dorsal centra,
the articular ball presents a iialf oval outline below, with slanting sides above,
and an emarginate summit. The measurements of the ball, indicating a suc-
cessive increase in the degree of flattening in the three specimens, arc as
follows :

272

Liucs.

Depth of specimen represented in Fig. 1, Plate XXXV , 44. 2

Breadth of specimen - CO. 0

Depth of second specimen 42. 0

Breadth of second specimen 01. (J

Depth of specimen represented in Fig. 2 39. 8

Breadth of specimen 63. 0

In the other three sijecimens, consisting of nearly complete dorsal centra,
and measuring about 4J inches in Jength, the compression is still greater.
In one of the specimens the distal articulation, represented in Fig. 3, is so
flattened as to appear transversely lenticular in outline and emarginate above.
It measures 30 lines in depth and 62J lines in breadth.

Seven selected specimens consist of caudals which have mostly undergone
little or no compression. They all pi'esent beneath a pair of strong processes
projecting obliquely backward from nearer the posterior part, and excavated
ill a conical pit directed backward and downward for articulation with chev-
rons. Three have been provided with strong diapopliyses projecting in
advance of the middle and nearly half way up the sides. A fourth specimen
has a small, narrow diapophysis projecting in advance of the middle and
about two-thirds up the sides. The remaining two vertebrae have no dia-
popliyses.

The caudals with diapopliyses have the articular ends of the body trans-
versely oval, witli a slightlj' hexahedral outline, emarginate above, and in a
less degree below. Tliose without diapopliyses have the articular ends of
proportionately less width, of less hexahedral outline, and not emarginate
below, so that they appear more cordiform than oval.

The largest caudal with diapophyses has measured as follows :

Lines.

Estimated length of centrum beneath 37.5

Estimated breadth of articular ends 48. 0

Depth of articular ends 42. 0

A smaller caudal with diapophyses, less mutilated, and represented in Figs.
4, 5, measures as follows :

Linos.

Length of centrum beneath 28. 5

Breadth of articular ends 44. 0

Depth of articular ends , , 40. 0

The caudal with small diapophyses, represented in Figs. 6, 7, measures as
follows :

273

Liues.

Length of centrum bcueatli .'><>. 0

Breadth of articuhir emls tO. 5

Depth of articular ends 30. 0

The better preserved of the caiidals without diapophyses, represented in
Fig. 8, measures as follows :

Lines.

Length of centrum beneath 24

Breadth of articular eud.s 38

Depth of articular ends 3G

The researches of Professor Marsh have proved the mosasauroid reptiles
to have had four limbs constructed as paddles and adapted to swimming.
Previous to his discoveries it was supposed that posterior limbs were absent.

Specimens of limb-bones, found in association with the vertebral specimens
above described, are supposed to belong to the posterior limbs, from the latter
pertaining to the back part of the column.

The femur represented in Fig. 9, Plate XXXV, is a broad bone strikingly
diiFerent from the humerus of Clidastes. The specimen is probably more^
flat than in the normal condition, as its many fractures are evidences of its
having been crushed.

The distal extremity is much the wider, and the upper extremity is but
little wider than the shaft. The head appears as a wide, lenticular, convex,
and very rugged surface. The lower extremity ends in a long, narrow, ellip-
tical, rusared surface for articulation with the bones of the fore-arm. From
the posterior part of the shaft there projects a thick, convex ridge, which
terminates above in an oval, flat, rugged surface, sloping from that of the
head of the bone.

The rugged, articular surfaces of the femur would appear to indicate a
cartilaginous continuity with the contiguous bones more intimate than in
Clidastes.

The measurements of the specimen are as follows :

Liues.

Length of femur ^"

Breadth of head ^^i

Breadth of distal extremity ^^

Breadth at narrowest part of shaft ^^

Thickness of head and trochanter 28

Greatest thickness of lower extremity '■ ^'^

The remaining two bones I take to be those of the leg, though I am
uncertain in regard to their relative position with cacli otlier mid llic icmm:
35 G

274

The specimen represented in Fig. 10 I suppose lu be a filnila, though it may
he an uhia. It is a broad bone, almost as wide as the femur, but not so long.
Its flatness has been somewhat increased by pressure. The upper extremity
presents a wide, lenticular, uneven, convex, and roughened surface for carti-
laginous union witli the femur. The lower extremity presents a similar sur-
face, Init wider and of less depth or thickness.

The measurements of the specimen are as follows:

Liues.

Length of fibula ". 66

Width of upper extremity 54:

Thickuess of upper extremity 21

Width of lower extremity, partly estimated 65

Thickuess of lower extremity 17

Width of shaft near middle 38

Thickness of shaft 13

The supposed tibia, represented in Fig. 11, is a mucii smaller bone than
the fibula. It is clavate, witli the lower extremity the more expanded and
thinner. The upper part of the shaft is compressed cylindroid, and becomes
wider and more compressed below. The upper extremity presents a trian-
gularly oval, slightly convex, articular surface, rugged as in the other bones.
The lower articular surface is transversely convex and widely lenticular.

The measurements of the specimen are as follows :

Lines.

Length of the tibia 45

Width of upper extremity 21

Thickness of upper extremity 14

Width of lower extremity 34

Thickness of lower extremity 11

Width of narrowest part of shaft 12

Thickness of narrowest part of shaft 10

Tylosaurus prorigee.

Dr. Sternberg's collection of Kansas Cretaceous fossils, ])reserved in tiie
Museum of the Smithsonian Institution, contains specimens pertaining to
several individuals of a large Mosasaurus-like reptile, approximating in size
the Maestricht Monitor of Europe, and tlie Mosasaurus MitcheUi of New
Jersey. The specimens appear to pertain to the same animal as that de-
scribed by Professor C-ope under the names of Macrosai/rus and Liodon pro-
riger, and afterward, as in the case of the former species, referred to another
genus by Professor Marsh, under the name of Rhinosaurus, then by Professor

275

Cope to Rliampliosauniy, and finally by Professor Harsh in Tylosaurus. A
series of specimens belonging to one individnal, from the yellow chalk ol
Kansas, consists of several' small fragments of jaws with bases of toetii, a
basi'OCcipital bone, and five vertebrsa.

The basiroccipital is obliquely distorted, from pressure. It has attached
the diverging processes of the basi-sphenoid. The condyle has approximated
3 inches in transverse diameter, and is about 2 inches in depth. The diverg-
ing processes of the basi-sphenoid, at their conjunction with the basi-occipital,
are about 3f inches wide. The vertebras are all more or less crushed ar/d
distorted. One of the specimens, a posterior cervical, has the body below 3
inches in length, and the truncated hypapophysis about 1^ inches in diam-
eter. The articular ball and socket approximate 2^ inches in diameter.

In three of the vertebral specimens, of about the same length as the pre-
ceding, the hypapophysis is rudimental. The remaining specimen is a more
posterior dorsal, and is of nearly the same size as the other vertebras.

A second series of specimens, belonging to another individual, consists of
several much-mutilated cervical centra, small fragments of jaws with bases
of teeth, a coronoid bone, a fragment of a quadrate bone, and the end of the
premaxillary.

The latter specimen, represented in Fig. 12, Plate XXXV, exhibits tlie
peculiar character of the extremity of the muzzle in Mosasaurus and its allies.
It forms a solid, conical, osseous prominence, with the end obtusely rounded
and projecting beyond the anterior teeth. The sides of the premaxillary
toward the end are perforated with large" vasculo-neural foramina. The pro-
jecting end of the bone extends about IJ inches in advance of the bases of
the first pair of teeth. Immediately in front of the latter there is a small
conical process.

Several specimens of a third individual consist of a caudal verteljra and
two teeth, which, from the adherent matrix, have been obtained from white
or creatn-colored chalk.

The vertebra is comparatively well preserved, not being crushed nor hav-
ing its body distorted, as is so frequently the case in the specimens which
have come under my observation. It is from the caudal series wifhout
diapophyses or transverse processes, and is represented in Figs. 1, 2, Plate
XXXVI. The posterior ball, defined from the body by a narrow ledge, and
the anterior cup are nearly circular, with a slight hexahedral disposition

276

The neural arch exliibits rudiments of zygapophyses. The bottom of the
body is provided with a pair of deep, conical pits for the attachment of a
chevron-bone. The pits are defined with a prominent margin most project-
ing anteriorly.

The measurements of the specimen are as follows :

Lines.

Leugth of the body inferiorly 20

Diameter of the body at the extremities 30

Of the two specimens of teeth, one is crushed nearly flat; the other, well
preserved, is represented in Fig. 3. It presents the usual form more or less
characteristic of Mosasaurus. It is curved conical, with the inner and outer
surfaces defined by acute ridges. The surfaces ai-e subdivided by longitudinal
ridges, becoming obsolete toward the point of the tooth. The intervals of
the ridges are feebly concave and faintly rugose. Internally near the base
they are delicately striate.

The length of the crown externally is 20 lines ; the diameter at base is 10
lines.

Several additional specimens, apparently belonging to another individual,
consist of small fragments of jaws and palatine bones with bases of teetli.
Among the" specimens is a portion of a splenial bone, with" its posterior artic-
ular surface nearly entire, as represented in Fig. 13, Plate XXXV. The
articular surface is a pyriform excavation, with a ridge descending from the
upper part internally to near its center.

LESTOSAURUS.
Lestosaurus coryph^us.

Dr. Sternberg's collection of fossils from the Smoky Hill River, of Kansas,
belonging to the Smithsonian Institution, contains numerous specimens of
dorsal vertebrae of a mosasauroid, which have the appearance as if they had
pertained to a single individual. There are about fifty of these vertebras,
but all have been more or less compressed from pressure of the superincum-
bent beds to that in which they lay, so that not a single specimen preserves
the exact original lorni. They ditfer but little in size, the more anterior
being somewhat shorter than the others.

The specimens appear to belong to the animal described by Professor
Cope under the name of Holcodus corypliceus, which Professor Marsh has
referred to another orcnus with the name of Lestosaurus.

277

•

Fig. 5, Plate XXXVI, represents one of the best preserved of the speci-
mens from the back of the series. In its present condition the centrum
beneath is 27 Unes long, and the ball and socket ends are about 16 lines in
depth and 2 inches in width. The neural atch between the ends of the fore
and aft zygapophyses measures 34 lines.

Another similar specimen, represented in Fig. 4, exhibits distinct rudiineuts
of a zygosphenal articulation. The length of its centrum beneatli is 33 lines.

The shortest of the series of the dorsals measures beneatli about 2 inches
in length ; the longest from the back of tlie series measures about 3f inches
in length.

The same collection contains six specimens of cervical vertebrae, which
may perhaps belong to the same species, if not the same individual, as the
dorsals above noticed. The specimens are all distorted from pressure. One
of them is an axis without the odontoid process and the suturally connected
pieces of the atlas. The articular ball of the centrum is transversely hexa-
gonally oval, 1.2 inches wide, and scarcely 1 inch deep.

Another cervical centrum, in some degree compressed from above down-
ward, is represented in Fig. 6, Plate XXXVI. It measures 1.9 inches in
length below and is 3 inches wide between the ends of the transverse
processes.

Another specimen, represented in Fig. 7, probably a second cervical, is
nearly complete, but considerably distorted. Its measurements are as
follows : * •

luelies.

Length of centrum inferiorly 2. 00

Length between fore and back zygapophyses 2. 80

Height from hypapophysis to end of spinous process 3. 20

De])th of posterior ball of centrum 1. 55

Width of posterior ball of centrum 1. 05

Dr. Sternberg's collection further contains a number of specimens of
caudal vertebra, probably belonging to the same species as the former, anil
apparently pertaining to two different individuals. There are twenty-six
.specimens, all provided wdth diapophyses or transverse processes, and with
hypapophyses for chevron articulation.

Figs. 8, 9, 10, Plate XXXVI, represent the first and last of a consecutive
series of four anterior caudals. The body of these has tiie length nearly as
great as the breadth and about equal to the depth. The neural arches are
without zygapophyses, or exhibit mere rudiments of tiiein. Tin- articular

278.

•

ball anil socket are wider tiiau high, and arc widest below the middle. The
outline of the articular surfaces is emarginatc and sloping at the sides above,
and seniicircular below. The neural canal is triangular. The transverse pro-
cesses project obliquely from th"fe lower part of the body, and they become
successively narrower. The hypapophyses are excavated into deep conical
pits, directed obliquely backward, for movable ai-ticulation with chevrons.
The pits are small in the first of the series of specimens and become succes-
sively larger.

Measurements of the two vertebrae represented are as follows :

Inches. 1 Inches.

Li^iigth of ceutrum, including edge of ball

Width of ball

Depth of ball

1. G5 1. 45

1.75 I 1.65
1. 50 1 1. 45

In a consecutive series of four posterior caudals with small diapophyses,
the bodies have nearly the same form as in the preceding, but the articular
extremities are of more uniform diameter and of a more hexahedral outline.
The transverse processes are small and project just below the center of the
sides. The chevron-pits are well developed, and resemble those of the pre-
ceding caudal specimens. Two of the caudals are represented in Figs. 11, 12,
Plate XXXVI.

The four caodals together measure f).3 inches in length. The diameters
of the cup of the first of the series is 1.4 inches ; the diameters of the ball
of the last of the series is 1.3 inches.

A mutilated posterior caudal centrum, apparently of the same animal as
the preceding, is without diajjophyses, but has well-produced chevron-pits.
The length of the centrum is less than the depth, and this is greater than the
width. The articular ends are hexahedral in outline. The ceutrum
measures 9 inch in length; 1.2 inches wide, and 1.3 inches deep.

The same collection contains the greater part of a palate-bone, with teeth,
represented in Fig. 12, Plate XXXIV, which may perhaps belong to the
same species as the specimens above described. The specimen contains the
remains of seven teeth, which probably is within two or three of the
complete series. The teeth are compressed conical, strongly curved back-
ward or hooked, obtuse in Cront, acute-edged behind, are perfectly smooth,
and present no facets or sul)divisioual planes of the surface.

279

Two limb-bones, represented in Figs 13, 14, Plate XXXVI, pertaining
to the same collection, are supposed also to belong to the same animal as the
above. I feel unable to determine their character. The broader one I sup-
pose to be an ulna or a fibnla. It resembles in its shape and construction
the corresponding bone of the New Mexico mosasauroid, represented in Fig.
10, Plate XXXy, but is much smaller.

Its measurements are as follows:

Indies. Lines.

Leugth at the upper extremity - 4 3

Breadth of upper extremity 2 9

Thickness of upper extremity 10

Breadth of lower extremity 3 4

Thickness of lower extremity 7

Width of shaft at middle 2 0

Thickness of shaft at middle 0 11

The smaller bone of Fig. 14 is probably a radius or a til)ia.
Its measurements are as follows :

■Inches. Lines.

Length 3 7

Breadth of upper extremity •. ■ - 1 4.}

Thickness of upper extremity 0 9

Breadth of lower extremity * 1 10

Thickness of lower extremity 0 9

Width of shaft at middle 0 . 9

Thickness of shaft at middle 0 7

MOSASAURUS (?)

The cabinet of Swarthmore College, in the vicinity of Philadelphia, con-
tains a number of fossils from the Cretaceous formation of Nebraska, pre-
sented by Mr. George S. Truman. They were collected by him from the
hills on the Missouri River, near the Santee Agency, in L'Eau qui Court
County. They consist of bones and teeth of fishes and reptiles, among
v^^hich are a number pertaining to the Polycotylus latiinnnls of Professor
Cope, originally described from remains found in Kansas.

An anterior caudal vertebra of a Mosasaurus, in Mr. Truman's collection,
is represented in Fig. 15, Plate XXXVI. The vertebra has the Ibrm usually
assigned to the genus. It retains the neural arch, but has lost its spine.
From the lower part of the body project the roots of strong transverse pro-
cesses. Beneath the body there is a strong pair of eminences projecting just

280

back of the middle and terminating in nearly flat articular fliccts fur a chevron.
The surface between these eminences forms a moderately deep concavity.
The measurements of the specimen are as follows:

Lines.

Lengtli of the body beneath 31

Depth anteriorly 35

Breadth anteriorly 42

Mr. Truman's collection contains several t;eeth which may probably belong
to the same animal as tlie vertebra just described.

The largest of the teeth is represented in Fig. 18, Plate XXXIV. It pre-
sents the usual mosasauroid form, being curved conical, with the inner and
outer surfaces unequal in extent and degree of convexity and separated by
acute ridges becoming more prominent near the apex of the crown. The
enamel is longitudinally striate, especially toward the base of the crown,
where more marked ridges show a tendency to divide the surfaces into narrow
planes.

The specimen is a shed tooth, and measures a little more than 2 inches in
length ; and the diameter at base is about 14 lines.

A second tooth, represented in Fig. 21, has nearly the same characters
as the former. It is smalle*, more compressed, so that its section is
more elliptical, and its inner and outer surfaces are more equal. It is also
a shed specimen, and measures IJ inches in length. Its base, an outline of
which is seen in Fig. 22, measures 10 lines fore and aft, and 8 lines trans-
versely.

The third specimen, represented in Fig. 19, has nearly the same form as
the preceding, but has its surfaces distinctly subdivided into narrow, slightly
depressed, smooth planes, of which there are six externally and seven intei--
nally. Transverse outlines of the base and of the crown a short distance
above are given in Fig. 20. The length of the tooth, also, like the other, a
shed sjiecimen, has been about 20 lines. The diameter of the base fore and
aft is lOf lines; transversely 8|- lines.

Fig. 16 represents a small tooth, accompanying the former specimens,
which I suppose to be from the back pari of the series of the same spe-
cies as the teeth of Figs. 18 and 21. It is more curved in proportion
with its length than in these, but has nearly the same outline in trans-
verse section, and has the enamel striated in the same manner. Its length
when complete has been about an inch. Its diameter at base fore and aft
is 64 lines; transversely .6 lines.

281

CLIDASTES.

The extinct reptiliiin genus' CUdastes, characterized by Professor Cope,
is especially distinguished from Mosasaurus and its nearer allies by the
possession of an additional mode of articulation to the ordinary one in
the vertebrae, such as is found in the living iguanas. The vertebrae are
otherwise nearly like those of Mosasaurus. The general form and construc-
tion of the skull and the character of the dentition are the same in both
genera.

Half a dozen species of CUdastes have been indicated by Professors Cope
and Marsh, from remains found in the Cretaceous formations of New Jersey,
Alabama, and Kansas.

Clidastes intekmedius.

A species different from those described by the authors just named is
indicated by a small collection of remains, presented to the writer by Dr. J.
C. Nott, formerly of Mobile. The specimens, consisting of several jaw-frag-
ments and vertebrae, were taken from an excavation 40 feet beneath tlie
surface, imbedded in the rotten limestone, . of Cretaceous age, in Pickens
County, Alabama.

The remains indicate a species of more robust proportions than Clidastes
propi/tlwn, described by Professor Cope, from the great part of a skeleton
discovered in the same formation near Uniontown, Alabama. It was a third
less in size than the typical species C. iguanavus, described by the same
author, from an isolated dorsal vertebra obtained from the Cretaceous green
sand of New Jersey.

Fig. 1, Plate XXXIV, represents the anterior extremity of a dentary bone,
probably more than one-half of the whole. It would appear to have been
proportionately of greater depth and thickness in relation with its length thim
in C. propython. It is also of more uniform depth at its fore part and less
pointed at the end.

The fragment contains the remains of a series of nine teeth, occupying a
space of 5^ inches. The teeth surmount robust osseous pedestals, of which
about Iwo-thirds of the length are included within about an equal extent of
the depth of the jaw.

The crown of a second tooth, (Fig. 5,) inclosed within a cavity of the
pedestal of its predecessor, is 5 lines in Icngtli and about 2i- lines in l)rca(lth
36 G

282

at base. It is curved conical, feebly compressed from without inwardly, and
has its inner and outer surfaces well defined b.y acute borders. The exposed
inner surface of the crown exhibits no divisional planes, and lias its enamel
minutely wrinkled.

The crown of a tooth (Fig. 4) occupying a corresponding cavity of the
ninth pedestal, probably not fully produced in its length, in its present condi-
tion has a breadth exceeding the latter. The crown is a broad cone about
the length of the tooth first described, ])ut with double the width at base.
The exposed inner surface is defined in the usual manner from the outer, and
exhibits no divisional planes. The enamel is minutely wrinkled.

The depth of the jaw-fragment below the visible base externally of the
first dental pedestal is. three-fourths of an inch ; the depth below the seventh
pedestal is 14^ lines.

The s[)lenial bone -advanced as far as the back part of the sixth tooth.
Beyond it the Meckelian groove is deep and wide compared with that in C.
yropython, and extends to near the end of the jaw.

Fig. 2 represents a posterior fragment of the opposite dentary bone, con-
taining the remains of a series of six teeth. The mutilated crowns of the
anterior two teeth retained in the specimen exhibit a swollen base, which
may also be seen to be the case in the crowns of the sixth and seventh teeth
of the anterior dentary fragment.

From the two fragments of opposite dentary bones I am unable to ascer-
tain the number of teeth which belonged to the complete series, but it seems
to me that the seventh tooth of the anterior fragment about corresponds with
the first retained tooth of the posterior fragment, which would indicate a
series of twelve teeth.

Fig. 10 represents an axis from the same individual as the preceding speci-
mens. It has the same form as that of C. i^yopijihon. The odontoid process,
and the elements of the atlas, all of which articulate suturally with the axis,
are detached from the specimen and do not accompany it.

I'lie measurements of the axis are as follows :

Lines.

Length of body tbrough center, devoid of odoutoid process 18

Breadth of axis between posterior ends of diapophyses , 28

Widtli of posterior ball -. lOJ

Height of posterior ball r ■ - • - r - 10

Width of hypopopliysis 8

Two mutilated dorsal vertebrae exhibit the zygosphenes and zygantra as

283-

well developed ])roporlionately as in Clidastes propi/tlion. Measurenieiils of
the better preserved of the specimens arc as follows :

Liues.

Leugtli of the boil.v iiiferiorly : IS

Width of the ball and socket 12

Height of the ball and socket 10

Clidastes affinis.

Some remains submitted to my examination by the Smithsonian Institution
-may perhaps indicate a species of .Clidastes distinct from the former. The
specimens were discovered by Dr. George M. Sternberg, "United States Army,
in the Cretaceous formation on the Smoky-Hill River, Kansas.

Fig. 6, Plate XXXIV, represents a nearly complete dentary bone, which
is accompanied by that of the opposite side. It contains the remains of a
series of twelve teeth, while there is one less in the other bone.

The anterior extremity of the jaw is of rather less depth and slightly
greater thickness than in the corresponding part of Clidastes intermcdius.
The splenial bone appears to have I'eached as far forward as the position of
the fourth tooth.

The anterior teeth appear to have been larger, and the intermediate ones
smaller, than in C. intermedius, though this may have been a variable char-
acter in the same species. Portions of the bases of the crowns of several of
the back teeth exhibit the enamel strongly striated, and the surfaces of the
teeth also present evidences of subdivision into narrow planes.
. A fragment from the back part of a maxillary from the same individual
contains the bases of four teeth. The last of the series retains part of the
crown, which is strongly- striated internally, and distinctly subdivided, into
narrow planes externally. In the remains of the teeth of the specimens
referred to C. intermedius there is no trace of subdivisional planes to the
crowns, but this may have been a variable character in the species.

Fig. 7 represents the back part of the right ramus of the mandible of the
same individual, seen on its inner side. It exhibits the same construction as
the corresponding part in C. propython. The articulation is nearly equally
divided between the angular and articular bones.

Measurements of the jaw-specimens are as follows :

Lines.

Length of dentary bone 12G

Length of serie.s of twelve teeth Ill

Depth of jaw below first tooth 10

•284

Lines.

Depth of jaw below fourth tooth 11

Depth of jaw at the outer side of the glenoid articulation 24

Length of projection back of the glenoid articulation 20

Transverse diameter of glenoid articulation 18

Vertical diameter of glenoid articulation 16

An axis and a dorsal vertebra accompanying the former specimens probably
pertained to the same individual. They are both considerably distorted from
pressure at the sides.

The axiS'is rather longer than that of C. interniedius, while its liypopophysis
is considerably smaller at the extremity, and the ball of the centrum is more
uniform in diameter, or is less emarginate above. The lower element of the
atlas remains in firm sutural connection with the body of the axis, but the
odontoid element of the latter and the lateral elements of the atlas are absent.

The dorsal specimen retains the neural arch with its characteristic zygail-
tral articulation.

Measurements of the vertebrae are as follows :

Length of axis through center of the body

Lines.
>>>>

Width of ball of body of axis 10^

Height of ball of body of axis 104-

Length of body of dorsal vertebra iuferiorly 22

Accompanying the former specimens there are several othei's which, if
they did not pertain to the same individual, probably belonged to the same

species.

Two fragments of the upper part of the cranium represented in Fig. 8
resemble the corresponding portions in Clidastes propijtlion^ as described and
figured by Professor Cope, and differ only in the greater size. Fig. 9 repre-
sents an isolated basi-sphenoid bone, probal)ly from the same skull.

These skull-fragments indicate an animal about one-third larger than C.
propython^ as described by Professor Cope.

It is a question of some importance how far. difference in size among the
mosasauroids may be a test of difference in species. Among the numerous
remains of these animals which have been discovered I have never yet
observed any which presented any evidence relating to age. In no case
have I seen a vertebra in which the neural arch was not continuous with the
centrum, so that I have been led to suspect that the former grew out of the
latter, as in most fishes, and was never united with it by articulation, as in
the crocodiles, &c. In this view of the case, some of the many described

285

species of mosasauruids may have been foundccl on differeiit ages of the
same.

Fig. 11 represents a humerus accompanying the former specimens, and
probably belonging to the same species, if not the same individual. In its
form and construction it closely resembles the corresponding bone of C. 2^>'o-
python.

The specimen is somewhat crushed, which perhaps to some extent makes
it appear proportionately flatter than the humerus of C. propython, described
and figured by Professor Cope.

The length of the bone does not exceed the breadth of its distal extremity,
which is the wider one.

The measurements of the specimen are as follows :

Lines.

Length of humerus at middle 35

Breadth of iiroximal extremity 28

Breadth of distal extremity 35

Breadth at constricted middle of shaft 20

Thickness of head 8i

Thickness of distal end 9^

Order Lacertilia. (J)

TYLOSTEUS.

Tylosteus oenatus.

The above name has been proposed for a supposed genus of lacertian
reptiles, founded on a singular fossil represented in Fig. 14, Plate XIX.
The specimen was obtained by Professor Hayden in the "Black Foot"
country, at the head of the Missouri River, and was probably derived from
the Cretaceous formation. It looks as if it might be an element of the
osseous dermal armor of some animal, whether reptile or mammal is by no
means certain, though, as before intimated, I suspect the former.

The specimen is imperfect or broken at the borders. Its inner surface is
concave !• the outer convex, and ornamented with large mammillary bosses.
The latter are about fifteen in number and of different sizes. They are
porous and of a less dense character than their shield-like basis. The
diameter of the fossil is about 2 inches ; its thickness an inch.

Accompanying the specimen just described there is an isolated phalanx,
represented in Fig. 13. Though suspected to pertain to the same animal,
the reference is uncertain. It is a ierminul phalanx nearly 2 inches long.

286

and with the expanded extremity nearly circular at the border and 16 lines
wide. The upper part of the bone presents a nearly straight slope in its
length, and is convex transversely. The under part is likewise straight along
the middle, transversely convex posteriorly, and nearly flat at the expanded
end. The lower surface of the latter presents near the middle a pair of
vascular foramina, and several similar foramina are found near the border.
The articular end is transversely -elliptical and barely depressed. Its trans-
verse diameter is 15 lines; its vertical diameter 10^ lines.

Order Sauro])te7-ijgia.
OLIGOSIMUS.

OlIGOSIMUS GRANDiEVUS.

A fossil ol)tained on Henry's Fork of Grreen River, Wyoming, during
Professor Hayden's exploration of 1870, would appear to indicate an extinct
reptile allied to Plesiosaurus and Discosaurus. In general aspect, the
specimen is different from those in company with it, and I think it doubtful
whether it was an associate of the other fossils, which belong to the Bridger
Tertiary formation. It was found as a detached specimen, and has no
adherent matrix. It probably is of Cretaceous age.

The fossil, represented of natural size in Figs. 18, 19, Plate XVI, consists
of the body of a caudal vertebra, apparently from the root of the tail. It
was evidently from a mature animal, as the neural arch was firmly co-ossified,
leaving no trace of the original separation.

In shape and construction the body resembles the corresponding portion
of the vertebrae in Plesiosaurus and Discosaurus, but the proportion of length
to the other dimensions is much less, and the depth also is not so great.

The body is biconcave, the concavities being of moderate and nearly equal
depth. Deepest at the central half of the area, the peripheral half of the
articular surfaces becomes more aljruptly shallower, and with the deflexed
edges somewhat convex. Near the border, the articular surfaces are defined
by -a narrow circular groove.

The posterior articular surface of the body at the sides below is deflected
in a pair of widely separated facets for a chevron-l>one. The facets are
sustained on processes extending forward more than a third of tlie length of
the body. Similar facets and processes are absent on the front of the bone.

2&7

Tlie sides of" ilie IxkIv are coinparativcly fcel)ly coiistriclcd, much leys lliau
in Plesiosaurus, and beneath, the constriction is triHing in degree.

Transverse processes or diapophyses project from the sides of tlie l)ody,
just above its middle and below tlic conjunction of the neural arch. Their
bases ate broadly conical; wider than high, and appear originally to have had
a sutural connection. The ends are broken off in the specimen.

The nsual nutritive foramina are visible at the floor of the verteljral canal
and beneath the body.

The peculiarities of the fossil appear to justify its reference to a previously
undescribed genus and species, and we have therefore attributed it to an
animal with the name at the head of this chapter.

The measurements of the specimen are as follows:

Lines.

Lengtli of body beneatb 12

Depth of body in front 19

Width of body iu front 23

Widtli of body at chevron-facets . 18

Width of vertebral canal 6

Leugtb of axis of tlie body 8

NOTHOSxiURUS.

NOTHOSAURUS OCCIDUUS.

The above name was appropriated to a saurian indicated by a detached
vertebral body or centrum, represented in Figs. 11 to 13, Plate XV. The
specimen was obtained by Professor Hayden on the Moreau River, a tribu-.
tary of the Upper Missouri, and is probably a Cretaceous fossil. In form and
construction it resembles the vertebral centra of Nothosaurus, an extinct
reptile of the Triassic formation of Europe, and probably it belongs to an
animal of the same order if not the same genus. The specimen appears to
pertain to a dorsal vertebra, to which the neural arcli was attached by broad
suture, as usual in the sauropterygians.

The body is nearly cylindric, longer than wide or liigh, and is moderately
narrowed a short distance from the ends. Inferiorly it jirescnts a central
roughness, probably for ligamentous attachment. The articular ends are
nearly round, but flattened above, and are neai'ly as wide as high. They are
slightly concave and exhibit a slight central protuberance, apparently the
ossified notochord.

The sutures for the neural arch extend nearly three-fourths the length

288

of the centrum from its posterior end, and they reach downward to the
middle of the sides. The bottom of the spinal canal is narrowest at the
middle, grooved on each side, and widens toward the ends of the centrum.

The measurements of the specimen are as follows : Length of centrum,
1 inch; depth in front, 10^- lines; width, 10 hnes.

FISHE8.

TELEOSTEI.

Order Acantlwpteri.

Sphyr^nid^.

CLADOCYCLUS.
Cladocyclus occidentalis.

The genus of fishes above named was proposed by Agassiz on some remains
consisting of large scales and portions of a vertebral column found in the chalk
of Lewes, England. The name was applied on account of the branching of
the tube in the scales of the lateral line ; and the fish was referred to the
sphyreenoids. (Poissons Fossiles, V, 103 ; Atlas V, Tab. 25 a, Figs. 5, 6.)

Some large scales, found by Dr. John E. Evans, and subsequently by Pro-
fessor Hayden and Mr. Meek, in ash-colored shales of the Cretaceous series
of Nebraska, I have supposed to belong to the same or a nearly allied genus.
The scales vary in form and size, and may probably belong to several species.
Mostly they are oval, with the length but little more than half the depth,
while others are circular, and these may really pertain to a different species,
if not genus, from the former.

A broad oval scale, somewhat distorted and broken at the edges, is repre-
sented in Fig. 5, Plate XXX. The inner portion exhibits numerous radi-
ating ridges, while the outer portion, separated from the former by a narrow
smooth tract, presents a minutely tubercular or granular aspect. The depth
of this scale is estimated to have been nearly 2^ inches, and its length nearly
1^ inches.

Another similar but less perfect specimen appears to have measured about
If inches wide by \\ inches long.

A third specimen^ represented in Fig. 21, Plate XVII, has measured rather
more than 1 inch wide and f inch in length.

Another scale, represented in Fig. 22, has (he same structure as the pre-

289

ceding, but is circular in tbrai. Its difimeter is about 14 lines. This prob-
ably belongs to a ilillerent species, and perhaps genus, from the ibrnier.

x\nother specimen is a nearly smooth oval scale, which has been about 13
lines wide and 9 lines long. It exhibits obscure radiant lines on the inner
portion, but no granulations are evident on the outer portion. This may
belong to another fish than that of the preceding specimens.

ENCHODUS.

Enciiodus Shumakdi.

The extinct genus above named was inferred by Agassiz from some remains,
consisting of jaws and teeth, found in the chalk of Europe, and was by him
attributed to the sphyreenoid family. Several species have been since de-
scribed from similar remains found in the deposits of Cretaceous age in the
United States. . One of these, under the above specific name, was indicated
Iiy a dentary bone with teeth, found by Dr. Benjamin F. Shumard in the same
formation in which were discovered the large scales referred to Cladocyclus.

The specimen is rudely represented in a reversed position in Fig. 20, Plate
XVII. The dentary margin of the bone is 11 lines long, and contains six long
narrow teeth, and in the back intervals a number of minute ones.

The first of the larger teeth is the longest, and is situated a short distance
from the end of the bone. Including its thickened base it is 2 lines long by
about one-fifth of a line wide. It is a long, narrow, straight cone, laterally com-
pressed, trenchant at the borders, and ends in a point with a slight posterior
projection or half barb. The posterior five larger teeth are situated at irreg-
ular distances apart, and measure from one to one and one-fiflli lines in
length by about one-sixth of a line in breadth at base. They are nearly like
the largest tooth, but are slightly more curved, and have no projection to the
back of the point. The minute teeth in the back intervals of the larger ones
and back of these arc not over the one-fifth of a line long.

PHASGANODUS.

PlIASGANOEUS DIRUS.

An extinct genus of fishes sujiposed to belong to the sphyrajnoid family,
and nearly related with Enchodus, has been described under the above name.
It was inferred from a specimen of a mutilated dentary bone with teeth,
37 G

290

imbedded in a piece of brown sandstone, obtained by Professor Hayden from
a Cretaceous deposit he has indicated as No. 5, on Cannon Ball River.

The specimen with the remains of five large teeth, reduced one-third, is
represented in Fig. 24, Plate XVII. The third tooth of the series, preserved
entire and separated from the former, is represented in Fig. 23.

The dentary bone exhibits nothing peculiar in the present condition of the
fossil, and appears not to liave differed in any important point from that of
Enchodus.

The teeth differ from those of the latter. They are proportionately shorter,
saber-like, and situated on broad bases, with an oblique direction to the edge
of the jaw. The thick back border is directed inwardly ; the trenchant
border forward and outward. The point is cut off in a slanting manner pos-
teriorly. The back part of the crown toward tiie base and extending on the
sides is fluted, but toward the point and trenchant border is smooth. In sec-
tion the crown is ovate, with the long diameter 2| lines. The length of the
tooth, including its thickened base, is 10 lines; without the base, the crown
measures 7 lines.

Order Malacoyteri.
SlLURID^E. (I)

XIPHACTINUS.

XiPHACTINUS AUDAX.

Under the above name, I described an ichthyodorulite belonging to the
collection of the Smithsonian Institution. The specimen was obtained from
the Cretacous formation of Kansas, by Dr. George M. Sternberg, United States
Army. I supposed it to l)e the pectoral spine of a large siluroid fish, but
according to Professor Cope, who has had the opportunity of examining many
remains of fishes from the Cretaceous formation of Kansas, it belongs to a
fish of a peculiar family. This he names Saurodontidee, represented by Sau-
rocephalus and some other genera. At first the spine was referred to the
last-named genus, but latterly he appears to be in doubt whether it belongs
to this or some other nearly allied genus. The specimen is represented in
Figs. 9, 10, Plate XVII, one-third the diameter of nature.

The spine is unsymmetrical, thus rendering it probable that it belonged to
one of the lateral pairs of fins rather than to any of the vertical fins. It is
a broad saber-shaped wenpon, in its present condition about 16 inches in

291

length, which is nearly its entire extent, judging from the tliinning and round-
ing of the broken end. Its breadth the greater part of the length is nearly
uniform, and at tlic middle is nearly 2 inches. Toward the distal end it
becomes slightly less wide and thinner; toward the proximal end it undei'goes
a greater reduction in width, and becomes much thicker.

The upper surface of the spine, represented in Fig. 10, for the most [)arl
is nearly Hat except toward the rounded borders. It is invested with a
tliiu layer of ossific substance of a nnn-e dense character than the compact
bone beneath. The surface is striated or ornamented with raised lines, which
are longitudinal and parallel, but on portions of the surftice are somewhat
irregular. Some of the lines branch, and the slightly divergent branches
include other commencing lines. At the distal end of the spine, near the
anterior border, the lines break up into finer branches which curve outwardly
to the edge.

The under surface of the spine (Fig. 9) is uneven. A prominent ridge,
commencing at its proximal extremity and occupying more than two-thirds
its width, extends outwardly and gradually declines to a point near the center
of the inferior surface. A shallow groove commences in front of the ridge,
widens outwardly, and extends beyond the former upon the anterior half of
the inferior surface of the spine. Back of the commencement of the ridge
there is a concave hollow, which narrows outwardly into a deep groove, and
this, pursuing the same course, widens and opens downward upon the posterior
half of the inferior surface of the spine to its distal end.

The posterior groove for nearly half its length proximally exhibits a row
of irregular pits at the bottom. The upper boundary of the groove in advance
of the pits is transversely striate, and beyond the position of the pits exter-
nally the corresponding surface presents the striae curling outward to the
back edge of the spine. The bottom of the groove, external to the position
of the pits, continues as a shallow channel running along the middle of the
spine inferiorly to its distal end.

The anterior border of the spine is convex in the length, obtuse internally,
and acute externally. The posterior border is concave longitudinally, obtuse
internally, and less acute externally than the anterior border.

The inner extremity of the spine appears bent upward into a hook-like
eminence with a pyramidal base extending above the general level of the
spine. The end of the hook-like process is broken off. Its inner surface

292

forms an ellipsoidal longitudinal convexity, with the lower half more
prominent and appearing to be an articular eminence. The outer extremity
of the spine is broken, but it appears to have been rounded transversely,
though it may have been pointed.

The measurements of the spine are as follows:

Inches.

Lengtli of the spiue iu its present couclitiou IG

Lines.

Breadth of the spiue beyond the articular hook 17

Breadth at the iuuer third 21

Breadth at tlie middle 23

Breadth uear the distal eud 20

Thickness of the spine beyond the articular hook 14

Thickness at- the inner third 9J

Thickness at the middle - 6

Thickness near the distal end 3

The transverse section of the spine near the middle forms an irregular

ellipse, as represented in the accompanying
figure. The left-hand side beneath represents
the posterior groove opening downward.

Since writing the above,* I have had the op-
portunity of examining the proximal half of a similar spine, from L'Eau
qui Court County, Nebraska. It was found in association with remains of
Mosasaiirus, &c., by George S. Truman, and presented by him to Swarth-
more College, Pennsylvania.

aANOIDEI.
PYCNODUS.

This genus, typical of an extinct family of fishes, was originally indicated
by Agassiz in the Poissons Fossiles. Many species have been described,
mainly from teeth and fragments of jaws with teeth, which are comparatively
large and stout, and were adapted to crushing hard food, such as mollusks
with their shells, crustaceans, &c. The remains have been found in the Tri-
assic, Jurassic, Cretaceous, and early Tertiary formations of Europe.

Pycnodus faba.

A specimen, represented in Fig. 16, Plate XIX, indicates a species to
which the above name has been given. It was submitted to my examination
by Dr. William Spillman, who obtained it from the Cretaceous formation near
Columbus, Mississippi. ' .

293

The specimen consists of a fragment of the ramus of a U)\ver jaw con-
taining a numl)er of teeth. Four principal teeth and part of the attachment
of another are retaineil in the fragment. These teetli are ranged oblicpiely
parallel with one another from within backward and outward. In outline
they are elongated-bean shaped, being slightly concave in front and convex
behind, and slightly wider externally than internally. The first of the series
is 7i lines wide by 2| lines fore and aft, and they successively increase in
breadth to the last, which measures 8| lines wide by 2j|- lines fore and aft.

At the bottom of the slope, to the inner side of the large teeth, there is a
row of three smaller teeth and the traces of attachment of a fourth one.
The three teeth, like the others, successively increase in size from before
backward. They are ovoid, and situated obliquely nearly opposite the inter-
vals of the large teeth. The first of the series is 2J lines in diameter fore
and aft and IJ lines transversely; the last one is 3 J fines by 2 fines.

The jaw-bone internal to the teeth just described rises in a ri<lge toward
the symphysis. The slope at the fore part of the ridge exhibits the attach-
ments of two minute teeth, indicating a second row internal to the largest
teeth.

To the outer side of the latter the specimen retains evidences of two rows
of smaUer teeth. Of these, the first row shows remains of seven teeth in
the length of space occupied by the five principal teeth, and, like these, they
successively increased in size. Only the fourth tooth of tln^ row is preserved,
and this is transversely ovoid, with tlie long diameter 2 lines wide and the
short diameter If lines.

Fig. 15, of the same plate, represents a specimen apparently from the same
species, belonging to tlie Museum of the Academy of Natural Sciences of
Philadelphia. It was presented by Dr. J. H. Slack, who obtained it from the
green sand marl of Crosswicks, Burlington County, New Jersey. It consists
of a small jaw-fragment containing three broad teeth simihir to the largest
ones above described.

An isolated tooth from New Jersey, submitted to my inspection by
Professor G. H. Cook, is noticed in the Proceedings of the Academy of
Natural Sciences of Philadelphia for 1857, p. 1G8, under the name of
Pycnodus rohustus. The specimen represented in Figs. 18, 19, Plate
XXXVII, has the same shape as in the largest teeth of those referred to
P. faba, but is mucli larger. Its long diameter is 14^ lines, and its short
diameter nearly 4 lines.

294

A similar tooth, nearly the same size but slightly more sigmoid, is repre-
sented in Fig. 96, page 244, of Professor Emmons's Report of the North
Carolina Geological Survey, published in 1858. Tiie specimen is attributed
to the Miocene Tertiary, and is referred to a species with the name of
Pycnodus caroHnensis.

HADRODUS.
Hadrodus priscus.

The genus above named is obscure in its relations, and was originally
described in 1857, in the Proceedings of the Academy of Natural Sciences
of Philadelj)hia. It was founded on a specimen consisting of a bone with
two singular-looking teeth, discovered by Dr. William Spilhnan, in the Cre-
taceous formation in the vicinity of Columbus, Mississippi.

The specimen represented in Figs. 17 to 20, Plate XIX, I have supposed
to be a jiremaxillary bone of an animal allied to the extinct genus Placodus,
■formerly considered to be a pycnodont tish, but now determined to be a
sanropterygian reptile,

The bone is nnsymmetrical, and sujiports two strongly co-ossified teeth.
Whether the specimen is complete in itself or whether it is part of a larger
bone, I have not been able to ascertain.

The bone is quadrate in outline; thicker and longer on one side, and
oblique at the upper border. The anterior surface is convex and compara-
tively smooth. On each side and extending posteriorly, the bone is deeply
excavated into large reserve cavities for successional teeth. The back surface
between the cavities inclines from each side, forming a median angular groove
descending to the interval of the teeth. The bone is more porous and striated
posteriorly than anteriorly.

The teeth remind one of the premolars of some pachyderm, rather thau
the teeth of a fish or reptile. They are not exactly alike, and are co-ossitied
with the bone by a firm osseous base or root, striated in front. They are
quadrate in outline, with the breadth and height nearly the same, and the
thickness about half. The crown is convex in front and at \he sides, and is
bilobed at the triturating border, which slopes off posteriorly. An acute
ridge and the conical blunted summits of the lobes define the outer from the
inner surface. Smooth enameloid substance invests the crown, extending"
twice the depth on the outer surface that it does on the inner suritice. In
transverse section the teeth are ovoid.

295
The measuremenfs of llic fossil are as follows:

Lines.

Depth of bone 18-20

Breadth of the bone 17

Length of the larger tooth 8

Width of same 8

Thickness of same 5^

Depth of enamel Cf

Length of smaller tooth 7f

Width of same 7J

Thickness of same 4+

Depth of enamel 0;^

I have arranged Hadrodiis with the Pycnodonts, though, like Placodus, the
discovery of additional material may prove it to be a sauropterygian reptile.
Of Placodus, Professor Owen remarks that the "teeth are implanted by
short simple bases in distinct hollow sockets," (Palaeontology, 218;) and IMeyer
says, "In wircklichen Alveolen stecken eigentlichen nur die Schneidezixhne
mit gut ausgebildeten Wurzeln, der Wurzeltheil der iibrigen Zahne ist mehr
rait dem Knochen, dem die Zahne angehoren, verbunden.'' Hadrodus in
the relation of the teeth would appear to be different, as they are firmly
co-ossified by short bases with the border of the jaw. They exhibit no
trace of implantation by sockets, though the successional teeth before being
established in a fixed manner in functional position must appear at least to
spring from sockets.

BLASMOBRANCHII.

Order Plagiostomi.

PTYCHODUS.

Ptychodus Mortoni.

The extinct genus of cestraciont fishes above named was inferred by
Agassiz, from isolated teeth, the only parts yet found which can l)c A\itii any
certainty referred to the same animal. A number of species have been indi-
cated, mostly by the same authority, from specimens ibund in the Cretaceous
formations of Europe and America.

Teeth of Ptychodus Mortoni have been discovered in the Cretaceous de-
posits of Alabama, Mississippi, and Kansas, but I have seen none fi'rim the
corresponding formation of New Jersey or elsewhere.

The Smithsonian Institution has submitted to my examination a collection

■296

of fouiteeii specimens of toctli obtained by Dr. George M. Sternberg, United
States Army, from the banks of Chalk Bluff Creek, a branch of Smoky Hill
River, about sixty miles east of Fort Wallace, Kansas. The specimens were
found in two parcels, each together, as if pertaiuiug to two individuals.

The two largest teeth, of which one is represented in Figs. 1, 2, Plate
XVIII, are probably from a median position in the mouth or jaws. They
are symmetrical in form, and in outline arc transversely quadrate oblong with
rounded angles.

The ci"ovvn is prominently convex, with the front and lateral borders nearly
straight, the back border slightly concave, and the angles rounded. Poste-
riorly it is impressed with a moderately concave crescentoid sinus. The
summit is crossed l)y a short transverse ridge, from which numerous ridges
radiate. Descending on the sides of the crown the ridges branch, and about
half way down terminate in a fine reticulation which extends to the borders
of the tooth. The root is a quadrate plate with the same outline of form as
the border of the crown.

Three other specimens of the same parcel as the preceding appear to
have been lateral teeth in relation to them in position in the mouth. They
are nearly alike in shape and size ; one of them -being represented in Figs.
3, 4. They are not symmetrical as in the larger teeth, and their onthne
is more reniform. They are proportionately narrower at one side, and wider
and more extended on a base beyond the conical elevation of the crown at
the other side. The sinus is of less height, and the ridges of the crown
are more convergent at the apex of the cone. The root appears to recede
from the narrower side and reaches nearly to the edge of the crown on the
opposite side. The remaining two teeth of the same parcel have the same
character as those just described, but are considerably smaller.

Measurements of some of the specimens are as follows :

Breadth transversely

Breadth antero-posteriorly .
Height from bottom of root

rig8.1,2.

Figs. 3, 4.

Lines.

XijiM.

Lines,

V2i

12J

Lines.

1.3

Of the two largest teeth, of the second parcel, which are nearly alike, one
is represented in Figs. 5 and G. They are intermediate in character to those

297 •

previously described, being less symmetrical than the large teeth and more
so than the smaller ones, and their crown is proportionately more prominent
than in any of them. Of three teeth smaller than the former and succes-
sively diminishing, that of intermediate size is represented in Figs. 7 and 8.
They have the same form as the unsymmetrical ones of the first parcel, but
have their crown proportionately much more prominent.

The remaining two teeth are different in shape from the former. The
larger one has tlie crown proportionately less prominent, with the central
conical elevation less strongly radTate. The iimer side of the base forms an
obtuse angle, and is strongly impressed toward the back border. The front
border of the base of the crown is short, nearly straight, and forms with the
oblique outer border an obtuse angle.

The smaller tooth is represented in Figs. 9 and 10, and has nearly the same
shape as the former, but the crown appears comparatively flat with a central
nipple-like eminence, and the anterior and outer borders are more continuous.

The measui'ements of the teeth are as follows : .

Figs.
5,6.

Figs.

7,8.

Figs.
9,10.

Breadth of crown transversely

Breadth of crown antero-posteriorly . .
Height of crown from bottom of root. .

Lines.

5
G

Lines.

7
4
4

Linos.

10
G
5J

Lines.
7

U
3i

Several specimens of teeth of Plychodus Moitoni have been submitted to
my inspection by Dr. William Spillinan, who obtained them from the Creta-
ceous formation near Columbus, Mississippi. One of the teeth, of large size,
and considerably worn at the summit of the crown, is represented in Figs.
11 and 12. It is symmetrical in shape, but has a more reniforni ontline than
the large teeth from Kansas. The anterior and lateral borders of the crown
nearly form a semicircle, and the posterior border is deeply emarginate.
The sinus is deeper than in the Kansas specimens, but the arrangement of
the striations of the crown appear to be the same.

Two other specimens, about half the size of the preceding, have nearly the
same shape, but have their crown proportionately more convex at the fore
part of the base.
38 G

298

The measurements of the Mississippi specimens are as

follows .

Figs. 11, 1-2.

Lines.
20
10
9J*

lAnes.
12
6|

Lines.

103

Brofidth of cro VTTi foro mid aft

* To wora summit.

The Museum of the Academy of Natural* Sciences of Philadelphia contains
nine specimens of teeth of Ptychodus Mortoni from the Cretaceous formation
of Alabama. These in general resemble the symmetrical and unsymmetrical
teeth above described. One of the specimens from Green County, Alabama,
is represented in Figs. 13, 14. Its sinus is more sharply triangular than in
the previous specimens.

Another tooth, approaching in size the largest Kansas specimens, has a
more distinct conical ridge on the summit of the crown from which the other
I'idges radiate. A third tooth nearly resembles the Kansas specimen repre-
sented in Figs. 3, 4, and has the summit of the crown worn away, as in the
large Mississippi specimen, represented in Figs. 11, 12.

Measurements of .Alabama specimens of teeth areas follows:

Figs. 1.3, 14.

Breadtli of crowu transversely

Breadth of crown fore ami aft

Height of crown from bottom of root. .

Lines.
16
lOi
10^

Lines.

14*
9

Lines.

Lines.
13

Lines.
9

Ptychodus occidentalis.

A peculiar species, to which the above name has been given, is indicated
by specimens of teeth discovered by Dr. John L. Leconte in an ash-colored
chalk of the Cretaceous formation a few miles east of Fort Hays, Kansas.

The most characteristic, and at the same time the largest specimen, is
represented in Figs. 7, 8, Plate XVII, of the natural size.

The shape of the tooth and the arrangement of the ridges of the crown
are quite different from what they are in the preceding species. The tooth
is symmetrical, as in the largest teeth o? Ptychodus Mortoni., but it is propor-
tionately of less brt'adtli transversely, and also higher.

299

The crown Ibniis a promiueiit cone with evenly sloping sides, and with a
t rails versel_y oblong square base narrowing a little posteriorly. The posterior
sinus t)t the crown comports in its height and breadth with the proportions
of the Ibrmer. The principal ridges of the surface of the crown cross the
summit and posterior slope transversely. Descending, they branch in a
divergent manner and anastomose, so as to form a comparatively coarse retic-
ulation, extending to the borders of the crown. The reticulation covers the
anterior slope of the crown and the sinus posteriorly. The direction and
arrangement of the ridges resemble those in the European Ptychodus decur-
rens, but in this the principal ridges are much coarser and more widely
separated. The root is mutilated in the specimen. The transverse diam-
eter of the crown is 14 lines ; its fore and aft diameter and its height about
1 inch.

Figs. 15, 16, Plate XVIII, represent two views of a small tooth, wh.ich
may probably belong to the same species. It is unsymmetrical, and is worn
away at the summit of the crown. The latter is proportionately less promi-
nent than in the large tooth, but has its ridges arranged in the same general
manner. The root is very thick in comparison with the size of the tooth.
The transverse diameter of the crown is 7i lines ; the fore and aft diameter
J inch.

Of five remaining specimens, one is a smaller and unworn tooth nearly
like that last described. Its crown is 5 lines wide and 4 lines from before
backward.

The specimen represented in Fig. 17 is more symmetrical, and nearly
resembles in shape the smaller symmetrical teeth of Ptychodus Mortoni, as
represented in Figs. 13, 14. The apex of the crown is not so pointed, but is
prolonged fore and aft in an acute ridge, and the rugae of the surface are not
convergent, but cross the summit in the usual transverse manner of the otiier
teeth. The breadth of the crown in this specimen is 4| fines ; the antero-
posterior diameter 3f lines.

The remaining teeth, of which the largest is represented in Fig. 18, have
a transversely ovoidal crown slightly elevated to one side of the center. The
surface is crossed by rugae in the same manner as in tlie large tepth.

300

The ineasiirciiioiils ol'tln^ three spi'oimeus aro

a^ i"

)ll()ws :

■

Liues.

Transverse diameter of the crown . .

Antero-posterior diameter of the crowu

Ptychodus Whippleyi.

Marcon, in his Geology of North America, describes and figures a tooth
from the Cretaceous formation near Galisteo, New Mexico, and refers it to a
peculiar species under the above name.

A similar tooth submitted to my inspection by Dr. Benjamin F. Slnimard,
from the Cretaceous rocks of Texas, is represented in Figs. 19, 20, Plate
XVIII. It is remarkable for the abrupt nipple-like prolongation of the
crown.

The tooth is unsymmetrical, and probably held a lateral position in the
series. The base of the crown is quadrate, witli the fore and outer borders
forming a single curve, while the other borders form a nearly right angle.
The nipple-like eminence of the crown inclines, as I suppose, outwardly.
The posterior sinus is shallow. The rugae of the surface of the crown cross
the summit transversely and diverge and branch descending upon the sides of
the cone. They are comparatively feeble, but this condition may be partially
due to friction. The surface of the base of the crown appears rather nodu-
lated than reticulated.

The breadth of the tooth at the base of the crown is 7 lines transversely
and fore and aft ; its height from the bottom of the root 8 lines.

The tooth resembles that of Ptychodus altior of Agassiz, from the chalk of
Sussex, England, as represented in Fig. 10, Plate XXX, of Dixon's Geology
of Sussex.

ACRODUS.

This extinct genus of cestraciont sharks, first described by Agassiz, was
represented in Europe l)y many species whose remains occur in the various
formations from the Permian to the Cretaceous inclusive.

ACEODUS HUMILIS.

A specicss to which this name has l)een given is indicated by an isolated

301

tuoth represented in. Fig. 5, Plate XXXVII, magnifieil 1^- diameters. The
specimen was obtained from the yellow limestone of the Cretaceous series,
near Vincentown, Burlington County, New Jersey, and it belongs to the
Museum of the Academy. The erown of the tooth is 7^ lines by 2J lines.
The extremities arc angular; the sides nearly straight or in the feeblest
degree sigmoid. The upper surface is convex; and its median ridge is almost
obsolete. The secondary ridges, proceeding transversely from the former,
become branched and finely reticulated at the boundaries of the crown.
The groove on the inner side of the latter, for co-adaptaticni to the contig-
uous tooth, is about three-fourths of a line in width. The fang or con-
tracted base of the tooth is about half the breadth of the crown.

Professor Emmons has represented the tooth of an Acrodus in Fig. 97 of
his Report of the North Carohna Geological Survey for 1858, which he attrib-
utes to the Miocene Tertiary. If it really pertains to this formation, it indi-
cates the latest known species of the genus. The species has been named
Acrodus Emmonsi

GALEOCERDO.

Galeoceedo falcatus.

The teeth of Galeocerdo are nearly as broad as they arc long, and the root
is but moderately notched. The anterior border of the crown is strongly
arched and oblique ; the posterior border is shglitly curved and nearly verti-
cal, but is abruptly prolonged backward at its base. The border's of the
crown are serrated ; the point is somewhat acuminate.

Teeth frgm the chalk formations of Europe figured in the " Poissons Fos-
siles," and ascribed by its illustrious author to half a dozen different species,
are, with reason, by Reuss referred to a single one with the name of Corax
heterodon. As Agassiz, according to Gibbes, does not now consider Corax
different from Galeocerdo, I have used this name, together with the earlier
specific one of falcatus, to represent the Corax heterodon of Reuss.

Many specimens of well-preserved teeth, submitted to my examination,
from various locaUties of the American Cretaceous formation, appear to belong
to Galeocerdo falcatus. The variations in the form and size of different teeth
I think are sufficiently accounted for from the difference of position the teeth
occupied in the jaws and upon difference in age.

Figs. 29 to 31, Plate XVIII, represent three of these teeth, obtained with

302

others by Dr. George M. Sternberg, United States Army, from the vicinity
of Camp Supply, on the North Canadian River, Indian Territory, probably
from a formation of Cretaceous age.

Their apparent specific identity with the teeth of Galeocerdo falcatus of
Europe is seen by comparing the figures with Fig. 43, taken from a tooth
imbedded in a block of chalk from Sussex, England.

Figs. 32 to 36 represent a series of similar teeth obtained, with many others
of the same character, by Dr. William Spillman, from near Columbus, Mis-
sissippi.

Figs. 37 to 40 represent smaller teeth, which I suspect to belong to the
same species, found by Dr. John L. Leconte, about three miles east of Fort
Hays, Kansas. Similar specimens were also obtained by Dr. Hayden, in
bed No. 2 of the Cretaceous rocks, near the mouth of Vermilion River,
Kansas.

Figs. 41, 42 represent small teeth, likewise of the same species, obtained
by Dr. Shumard from the Cretaceous Ibrmation of Texas.

OXYRHINA.

The teeth of Oxyrhina have a simple, compressed demiconical crown, with
sharp borders, and without lateral denticles.

OXYEHINA EXTENTA.

Figs. 21 to 23, Plate XVIII, represent specimens of teeth of an Oxyrhina
discovered by Dr. George M. Sternberg, United States Army, in the vicinity
of Camp Supply, on the North Canadian River, Indian Territory. Figs. 24,
25 represent similar teeth found by Dr. William Spillman in the Cretaceous
formation near Columbus, Mississippi. These teeth differ especially, from
those of other species previously described and figured, in the greater pro-
portionate extension laterally of the base of the ci-own. They most nearly
resemble the teeth of the Oxyrhina Mantelli of the chalk of Europe.

In the Museum of the Academy of Natural Sciences of Philadelphia there
is a specimen of an Oxyrhina tooth in a block of chalk from Sussex County,
England, resembling those just described in the unusual extension laterally
of the crown. If this specimen pertained to O. ManteMi, it is probable that
the specimens from Mississippi and the Indian Territory do likewise. It
was not until after I had described the latter under the above name that I

303

noticed the specimen from the English chalk. My comparisons had been
made with the figures of Agassiz, Dixon, and Reuss, and in none of" these do
the teeth exhibit so conspicuous a lateral extension of the base of the crown
as in the American specimens and the English chalk specimen of our Museum.
An exception to this statement may be made in reference to Fig. 26, Plate
XXX, in Dixon's Geology of Sussex, representing a tooth, which is rcferi-ed
to Lamna acuminata.

Measurements of the specimens referred to Oxyrhina extenta are as follows:

Specimens represented in Pljite XVIII.

Vis.. 21.

FiK. 2-i.

Fiff. 23.

Fig. 24.

Fiff. 25.

Lines.

Length from notch of root .
Length of crown at middle
Breadth of crown at base .

Breadth of root

Thickness of root

IJncs.
12

8-
15
17

4.^

Lines.

12
13
4i

Lines.

14
12

Lines.
10

13
14

LAMNA s. OXYRHINA.

The teeth of Lamna are in general . characterized by the long, narrow
crown, with a single denticle on each side of the base, and a strong root with
narrow branches separated by a deep notch Those of Oxyrhina usually
have a broader crown without lateral denticles, and also have a broader root
with a shallower notch. In both genera, however, the proportion of breadth
to length, and most other characters, except the presence or absence of the
lateral denticles, vary in different parts of the jaws. In both, the side teeth
are wider than those in advance, the disproportion usually being greater in
Oxyrhina than in Lamna. Some of the teeth in the two genera so nearly
assume the form of one another, that when isolated fossil teeth of either are
•found without the base it is sometimes difficult to know to which to refer
them.

A number of times I have seen specimens of teeth, reputed to have been
derived from the Cretaceous formation, which so closely resemble those of
certain Tertiary species of Lamna, except in the possession of lateral denti-
cles, that I have suspiciously regarded-them as pertaining to the same. The
absence of denticles I tlionght might be accidental or abnormal. The report
that the teeth had been found in a Cretaceous formation I suspected might

304

be a mistake ; or, if they had, that they were, perhaps, accidental in their
occurrence in that formation, and had probably been derived from some con-
tiguous Eocene deposit. The frequent repetition of the same thing has led
me to view the specimens as having really pertained to Cretaceous fishes.
The absence of the lateral denticles would refer the teeth to the genus Oxy-
rhina, and the general form and other characters rather to the genus Lamua.
May the teeth not be regarded as having belonged to Oxyrhina ancestors of
some of the later Lamnse 1
,.Fig. 44, Plate XVIII, represents a tooth which lies iml^edded in a portion
of gray rock, obtained by Dr. John L. Leconte from the Cretaceous forma-
tion three miles east of Fort Hays, Kansas. The specimen is perfect and
unabraded. In all respects it is like the teeth of Lamna cuspidata of the
early Tertiary deposits, except that it is devoid of lateral denticles, and pre-
sents no trace of ever having possessed them.

Fig. 45 represents a tooth, which lies in a block of chalk, from Sussex,
England. The siiecimen is preserved in the Museum of the Academy of
Natural Sciences of Philadelphia. Like the former, it closely resembles the
teeth of L. cuspidata, but exhibits no trace of lateral denticles.

Figs. 46, 47 represent two teeth which the writer found with the skeleton
of Hadrosaunis Foulkii and shells of Exogyra costata, Ammonites placenta,
&c., in clay near Haddonfield, Camden County, New Jersey. These speci-
mens, unworn and perfect, except in positions having no relation with the
point in question, are identical in character with the teeth of Lamna elegans
of the early Tertiary deposits, except that they exhibit no trace whatever of
the existence of lateral denticles.

Figs. 48, 49 represent two teeth selected from eight specimens obtained
by Dr. AVilliam Spillman from the Cretaceous formation near Columbus, Mis-
sissippi. Most of the specimens are complete and well preserved, and in no
instance exhibit traces of lateral denticles, while in all other respects they are
like the teeth of L. elegans.

Seven specimens of teeth from the Cretaceous formation of Green County,
Alabama, presented to the Academy of Natural Sciences of Philadelphia by
Dr. Joseph Jones, also agree with those of L. elegans, except that they have
no lateral denticles.

In a collection of similar teeth, presented to the Academy by "William M.
Gabb, in all the specimens retaining the root, twenty in number, the lateral

305

denticles are absent. Most of the teeth appear slightly water-worn, but the
best of them exhibit no trace of the lateral denticles. These specimens were
obtained by Mr. Gabb from the Cretaceous green sand of Mullica Hill, Glou-
cester County, New Jersey.

Fig. 50 represents a tooth which lies partially imbedded in a fragment of
gray sandstone, obtained by Professor Hayden from the Cretaceous deposit,
indicated by him as No. 2, near the mouth of Vermilion River, Kansas. In
the attempt to dislodge the tooth from its matrix the ends of the root were
bi'oken off, but it is otherwise complete. It also appears not to have pos-
sessed lateral denticles, but otherwise is like the teeth of X. elegans.

Roemer describes and figures a tooth, (Kreidebikkmgen v. Texas, page 29,
Plate I, Fig. 7,) mider the name of L. Texana, from the Cretaceous forma-
tion of Texas. The figure represents wkat appears to be a perfect tooth
without lateral denticles, and otherwise resembles those of L. elegans.

Dr. B. F. Shuraard also submitted to my inspection several teeth from the
Cretaceous formation of Texas resembling those of L. elegans, but in these
the root was broken off, excepting on one side of one specimen, and in this
no lateral denticle existed.

Notwithstanding all that has been stated above, I must add that I have
noticed among collections of teeth of L. elegans from Tertiary formations
specimens in which the latei-al denticles were feebly developed, and others in
which they were entirely absent. In some of the latter, traces of their acci-
dental detachment were perceptible, but in others I could see none.

It would appear, however, from the facts thus given, that during the Cre-
taceous period there existed two species of sharks in which the teeth resem-
bled those of L. ciisjndata and L. elegans of the Tertiary period, except that
the teeth possessed no lateral denticles. The two Cretaceous sharks were
probably the ancestors from which the species just named were evolved.

OTODUS.

Otodus divaricatus.

Among a small collection of fossils submitted to me for examination by Dr.
William Spillman, of Columbus, Mississippi, there is a specimen of a shark-
tooth of rather peculiar character, which is represented in Figs. 26 to 28, of
Plate XVIII. The specimen is labeled "lime formation," Texas, and noth-
39 G

306

ing is further known in relation to its locality, but I suspect it to be of Cre-
taceous age. Of known species, it bears most resemblance to the teeth of
Otodus semiplicatus, Ag., of the chalk of Europe. It also has some likeness
with a tooth from the chalk of France, represented in Fig. 11, Plate LXXVI,
of Grervais's Paleontologie Franqaise.

The crown forms a narrow demicone, with an expanded base supporting a
pair of inwardly-diverging denticles. The surface of the principal cone near
the base is plicated. The root is thick and deeply notched, and extends pos-
teriorly more than half the length of the tooth. The anterior surface of the
crown in the median line is as long as the base is wide, and is about one-fifth
greater than the posterior surface.

The measurements of the specimen are as follows :

Lines.

Length of tooth at raiddle 16

Length from ends of the root 21

Breadth at ends of the root 15J

Length of crown iu front 13

Length of crown behind 10

Breadth of crown at base 12g

Holocephaii.

EDAPHODON.

In the extinct chimseroid fish Edaphodon the inferior maxiliarics are pro-
duced anteriorly in a long beak, and the superior maxillaries are provided
with three large dental areas. In the allied genus Ischyodus the inferior
maxillaries are not prolonged in a beak, and the upper ones are provided with
four large dental areas.

Edaphodon mikificus.

A species under the above name was indicated by the author in the Pro-
ceedings of the Academy for 1856, page 221. It was founded on eight speci-
mens of maxillaries obtained from the Cretaceous green sand of Burlington
County, New Jersey, by Professor (jeorge H. Cook, during the State geo-
logical survey.

The inferior maxillaries, represented in Figs. 6 to 9, Plate XXXVII, are
about twice the length of the depth. The two rami converge in a curve, and
end together in a long, bird-like beak, (Fig. 6.)

The outer surface (Fig. 7) of each ramus is lozenge-like in outline, defined

307

by a concave upper border, a convex anterior border, a short, oblique, poste-
rior border, and a convex lower border. The surface is concave longitu-
dinally, and is convex transversely in front and behind, and concave in the
middle.

The inner surface (Fig. 8) is flat transversely, slightly convex longitudin-
ally, and with the fore and back borders prominent. It is moderately stri-
ated in the length, and at its upper part presents a symphysial bevel, extend-
ing the length of the beaked portion of the bone.

The oral surface (Fig. 6) on the beak is concave fore and aft, and at the
back half of the bone forms a lozenge-like plane sloping inwardly, and having
the outer border elevated. The sloping plane exhibits at its fore part inter-
nally a large cordiforni dental area, with the notch at the base of the beak.
Externally to this area, near the fore part of the crest defining the outer part
of the sloping plane, there is a second much smaller elliptical dental area.
These two areas are separated by a groove, widening forward upon the oral
surface of the beak, where it presents a third dental area. This is the third
in size, is oval in form, and is situated just in advance of the outer part of .the
largest dental area.

A fourth area, smaller than the others, occupies the back extremity of the
symphysial bevel to the inner side of the anterior part of the largest dental
area. The dental column which forms this fourth area produces the prom-
inent ridge defining the inner surface of the ramus mandibuli posteriorly.

Beside these dental areas, two or three others are observed at the end of
the beak. One of them curves from the symphysis outward and backward on
the outer edge of the point of the beak. Another smaller oval one is situated
at the edge of the symphysis behind the commencement of the former. In
one specimen a still smaller oval area is situated just behind the outer end of
the curved area, but in the other specimens it appears not to be distinct from
the latter.

The dental areas in the fossils appear as depressed and decomposed,
friable, white, chalky tracts, with harder calcigerous tubules of the vaso-
dentiue projecting from the surfaces. The tubercular eminences originally
occupying the position of the areas and terminating the dental columns
have disappeared, leaving depressed surfaces. The vaso-dentiual columns
corresponding with the areas on the triturating surface are visible at the
posterior-inferior extremity of the mandibles, as seen in Fig. 9.

308

The upper maxillaries, represented in Figs. 10 to 12, bear a near resem-
blance to those of Edaphodon BucJdandi and E. Icptognathus, as represented
in Tab. 40 d, of the third volume of the Atlas of Agassiz's Poissons Fossiles.

The outer surface (Fig. 11) of each maxilla is a broad, sloping plane, the
inner surface a vertical plane. The upper surface is also flat, but is occupied
at its inner back pai't by a wide, deep gutter, ending forward in a pit.

The palatine surface (Fig. 10) of the two bones conjoined at its back part
forms a wide, transverse concavity, nearly flat in the middle, but curving
downward at the outer part. The palatine surface inclines forward to the
anterior subacute termination of the bones. The lateral border of each max-
•illa at the palatine surface is strongly sigmoid.

Three large dental tubercles occupied the palatine surface of each max-
illa, indicated in the fossils, as seen in Fig. 10, by tliree depressed areas of
white, decomposing vaso-dentiue. The largest area is posterior and internal.
It is broken at its back part in the fossils, but, in the entire condition, appears
to have been reniform in outline. Immediately in advance of this area is
another with an oblong cordiform outline ; and external to the largest one is
the third area, about as long as this, but not more than half the breadth, and
having a clavate outline.

The dental columns corresponding with the three dental areas are seen
at the back of the maxillae, the largest one below the position of the two
smaller ones, as represented in Fig. 12.

The measurements of the specimens are as follows :

Inferior maxillary.

Lines.

Extreme length of bone C4

Leugth of beak along the symphysis 40

Length of anterior border of ramus 44

Leugth of posterior or upper border bcack of the beak 26

Width of inner surface 26

Width of upper surface back of the beak .* 24

Width of the large posterointernal deutal area 13*

Estimated breadth fore and aft 10

Width of external dental area ~ 7

Estimated breadth fore and aft , 3

Diameter of anterior deutal area fore and aft ., 4

Diameter of same transversely - 3

* The size of tlie deutal areas is iu some measure uncertain, as iu some cases they appear to havo
been more or less estomled in the fore and aft diameter by fracture over the position of the dental
columus.

309

Superior maxillary.

Lines.

Extreme length of bone 5S

Length 6T bone internally 43

Bi'eadth i>osteriorly 23

Diameter fore and aft of large postero-internal dental area 18

Diameter of same transversely , 12

Diameter fore and aft of anterior dental area 11

Diameter of same posteriorly and transversely 5

Diameter fore and aft of external dental area 16

Diameter transversely of the same where widest 5

EUMYLODUS.

EuMYLODUS LAQUEATUS.

Among some fossils from the Cretaceous sandstone near Columbus, Missis-
sippi, submitted to my examination by Dr. William Spillman, there is a spec-
imen of the maxillo-dentary apparatus of a chimaeroid fish, related with
Ischyodus, but apparently distinct from that genus. The specimen is repre-
sented in Figs. 21, 22, Plate XIX, and Figs. 13, 14, Plate XXXVII. It
most resembles, in its general form, the mandible of Ischyodus, as repre-
sented in Fig. 20, Tab. 40, of /. Townsendi, and Fig. 16, Tab. 40 c, of I.
Agassizi, of the third volume of the Atlas of the Poissons Fossiles.

The bone is of denser character than the corresponding one of Edaphodon,
and in this respect and several others is more like that of Leptomylus, de-
scribed by Professor Cope.

The outer surface (Fig. 14, Plate XXXVII) is nearly Hat, but slightly
depressed below, and bent outwardly behind from the triturating surface.
The inner surface (Fig. 21, Plate XIX) is fluted ; the anterior third presents
a succession of three curved ridges separated by two grooves ; the median
third forms a wide, concave groove ; and the posterior third forms a nearly
square plane, sloping from the triturating surface backward and inward, and
defined by a subacute border from the outer surface of the bone.

The anterior border of the mandible appear-s as curved cylindroid termina-
tion of the bone. No appearance of a distinct symphysial surface exists.

The oral surface (Fig. 22, Plate XIX) is uneven, and conforms in its out-
line with "the inner and outer faces of the bone. The anterior most promi-
nent portion is convex, and exhibits some scratches and polisli, due to its
masticating function. Its posterior two-thirds incline from a median dentary
ridge, moderately without and behind, but steeply within.

310

The dcntary ridge is near the median line of the oral surface, extending
about half its length, but nearer its posterior than anterior extremity. As
seen in Fig. 13, Plate XXXVII, it appears to be composed of the prominent
tubercular extremities of three connate columns, of which the back two
appear oval, and the anterior one rather clavate in outline.

The measurements of the specimen are as follows :

Lines.

Length or depth of the anterior border 32

Length or depth of the posterior border . '. 11

Thickness of the anterior column or border 6

Thickness at the second ridge of the inner surface 6^

Thickness at the third ridge of the inner surface SJ

Thickness at the middle concavity of the inner surface 7^

Thickness at the commencing ridge of the posterior slope of the inner surface. . . 10

F5re and aft extent of triturating surface 36

Length of dental tract 19

NOTICE OF SOME REMAINS OF FISHES FROM THE CARBONIF-
EROUS FORMATIONS OF KANSAS.

The remains described below were obtained by Dr. F. V. Haydeu and
Mr. F. B. Meek in the summer of 1858, and were originally noticed by the
writer in the Proceedings of the Academy of Natural Sciences of Philadel-
phia in January, 1859.

Plagiostomi.

CLADODUS.

Cladodus occidentalis.

The extinct genus of cartilaginous fishes, Cladodus, was first characterized
by Agassiz from isolated teeth from the Coal-formation of Europe. A
species of the same genus is indicated by a fragment of a tooth discovered
by Messrs. Hayden and Meek in the upper Coal-measures of Manhattan
Kansas.

The specimen has lost one-half its base, a large portion of its principal
cusp, and the points of the lateral cusps, but sufficient remains to give us a
correct idea of the form of the perfect tooth, as represented in Figs. 4 to 6,
Plate XVII.

The base of the tooth is oblong in outline, with the inner border some-
what angular and the outer one concave. Its upper inner surface slopes from
the cusps, and near its margin, a short distance from the extremities, supports
a pair of oval tubei'cles. Similar protuberances occupy a position beneath
the base externally.

The median or principal cusp of the tooth is elongated demiconical, with
acute lateral edges. The inner convex surface of the cusp at its base exhibits
sharp, oblique folds or striae, as represented in Fig. 4. The outer less convex
or nearly flat surface is smooth, except a few vertical wrinkles at its base.

The lateral denticles on each side of the principal cusp are two, of which
the outer is the larger.

312

In its perfect condition the tooth has approximated I4 inches in length,
and about 1 inch in breadth at l)ase.

A simihar tooth from the coal-measures of Illinois has been described
under the name of Cladodus mortifer by Professor Newberry, in the second
volume of Worthen's Geological Survey of Illinois, published in 18G6. Mr.
Orestes St. John has likewise described some teeth of the same species from
the coal measures of Nebraska, in the Proceedings of the American Philo-
sophical Society for 1870, and in Hayden's Report on the Geological Survey
of Nebraska, published this year.

XYSTRACANTHUS.

Xystracanthus arcuatus.

A second cartilaginous fish of the Coal-period is indicated by a remarkable
dorsal spine, discovered by Messrs. Meek and Hayden in the Upper Carbon-
iferous rocks of Leavenworth City, Kansas. The specimen, represented in
Fig. 25, Plate XVII, lies partially imbedded in a piece of yellowish lime-
stone, also containing a few minute crinoid segments. The point of the spine
and its root of insertion are destroyed, and the specimen is otherwise muti-
lated and appears somewhat crushed, but it is sufficiently characteristic to
distinguish it from ichthyodorulites previously described.

The spine is strongly curved, appears flattened at the sides, and is rounded
at tlie borders. Its transverse section is narro\V ovoid, with the narrower
extremity toward the convex border. The spine is longitudinally striated,
and in its present condition the bone is brown and quite friable. The sides
and concave border of the spine are furnished with white, shining, enamel-
like tubercles of various sizes. The smaller ones are half ovoid ; larger
ones are conical or half conical ; and the largest, which occupy the upper and
lower part of the concave border, are crescentoid, and embrace the latter. In
shape and attachment the larger tubercles remind one of minute polypori
projecting from the stem of a tree. They are convex above, and flat, or
slightly concave, below.

PETALODUS.
Petalodtjs alleghaniensis.

Petalodus is another extinct genus of cartilaginous fishes, allied to our
living sharks, which was originally characterized by Owen, and was also
established on isolated teeth from the Carboniferous formations of Europe.

313

A species of the same genus, under the above uame, was described by the
author in the Journal of the Academy of Natural Sciences for 1856, from a
specimen found in the Coal-measures of Blair County, Pennsylvania. A sim-
ilar tooth was also described and referred to the same species in the Pro-
ceedings of the Academy for 1859, which was obtained by Messrs. Meek and
Haydeu from the Upper Carboniferous formation of Fort Riley, Kansas. The
specimen is represented in Fig. 3, Plate XVII.

The crown is broad, and somewhat lozenge-shaped in outline. The base
is bordered by a thick annulated ridge, arching downward toward the middle
and moderately deflected at the extremities. The free border is sharp and
somewhat arcuate, and the apex is slightly acuminate. The anterior sur-
face of the crown slopes outwardly. The posterior deeper surface is concave
at its lower median portion. The fang is about as long as the crown is exter-
nally, but is not so wide. Its extremity is angular and everted.

The measurements of the tooth are as follows :

Lines.

Length of tooth iu the entire condition about 19

Breadth of crown at base 20

Length of crown externally 9.^

Length of crown internally 12

Length of fang externally 9^

Breadth of fang 14

Similar teeth from the Coal-measures of Illinois have been described by
Professor Newberry, under the name of Petalodus destructor, in the work
above mentioned. Others have also been described or indicated, from the
Coal-measures of Indiana, Iowa, and Nebraska, by Mr. St. John, likewise in
the works above named.

ASTERACANTHUS.

ASTERACANTHUS SIDEEIUS.

Incidentally, I take the opportunity of describing a fossil submitted to my
examination by Professor J. M. Satford through Professor Hayden. It was
obtained near Glasgow, Tennessee, and is reputed to be of Sub-carboniferous
age. The specimen consists of a fragment of an ichthyodorulite, or fossil-
iish spine, and is represented in Fig. 59, Plate XXXII. It appears to indi-
cate a species of the extinct genus Asteracanthus, the remains of which had
previously only been found in formations of later age than that above men-
tioned.

40 G

314

The fragment is from an intermediate position at the junction of the root
and shaft, and is a little over 3 inches in length. It looks as if when in a
complete condition it had been upwards of a foot in length, approximating
that of the dorsal spine of A. ornatissinms. Broken off at both extremities,
and also posteriorly, so as to leave no portion of the usual groove, it appears
as a solid, porous bone-fragment, triangular in transverse section toward the
apex, and oblong toward the root.

The sides of the shaft are closely studded with mammillary tubercles,
arranged in rows directed upward and forward. The tubercles incline in the
same direction, and have their sides longitudinally striated. Their summits
are worn away, the extent of abrasion increasing, approaching the anterior
border of the spine.

SYNOPSIS OF THE EXTINCT VERTEBRATA DESCRIBED OR
NOTICED IN THE PRESENT WORK.

MAMMALIA.

Carnivora.

FELIS;

FeLIS AUGUSTUS. *

Leidy : Pr. Ac. Nat. Sc. 1872, 39.

Described page 227 of the present work, and represented by Figs. 18, 19,
Plate VII, and Fig. 24, Plate XX. From the Pliocene of the Niobrara
River, Nebraska.

Felis imperialis.

Founded on an upper-jaw fragment, containing the second premolar tooth,
from the Quaternary of California. Described page 228, and represented
by Fig. 3, Plate XXXI.

Canid^.

CANIS.
Cants indianensis.

Leidy : Ext. Mam; of N. America 1SG9, 368.

Canis primccvus. Leidy : Pr. Ac. "Nat. Sc. 1854, 200 ; Jour. Ac. Nat. Sc. 185G,
III, 1G7, Plate XVII, Figs. 11, 12.

Founded on an upper maxillary with teeth from the banks of the Ohio,
near Evansville, Indiana. Also indicated by the ramus of a lower jaw
from California. Quaternary.

See page 230 for description of the latter specimen, represented by Fig. 2,
Plate XXXI.

Canis vafer.

Leidy : Pr. Ac. Nat. Sc. 1858, 21 ; 1870, 109 ; Ext. Mam. of N. America 18G9, 3G8.

Founded on jaw-fragments with teeth from the Pliocene of the Niobrara
River, Nebraska, and Sweetwater River, Wyoming.

316

FAMILIES UNDETERMINED.

PATRIOFELIS.
Patriofelis ulta.

Leidy : Pr. Ac. Nat. Sc. 1870, 10 ; Haydeu's Eep. Geol. Sur. Wyoming 1871, 344;
Hayden's Eep. Geol. Sur. Montana 1872, 355.

Founded on the mutilated rami of a lower jaw from the Bridger Eocene
Tertiary, "Wyoming. Described page 114, and represented by Fig. 10,
Plate II.

UINTACYON.

Probably the same as Miacis, described by Professor Cope in the Proc.
Am. Phil. Soc. 1872, 470.

UlNTACYON EDAX.

Leidy : Pr. Ac. Nat. Sc. 1872, 277.

Founded on the ramus of a lower jaw from the Bridger Eocene Tertiary
of Wyoming. Described page 118, and represented by Figs. 6 to 10,
Plate XXVII.

UlNTACyON VORAX.

Leidy : Pr. Ac. Nat. Sc. 1872, 277.

Founded on a lower-jaw fragment from the Bridger Eocene Tertiary of
Wyoming. Described, page 120, and represented by Figs. 11 to 13,
Plate XXVII.

SINOPA.

SiNOPA RAPAX.

Leidy: Pr. Ac. Nat. Sc. 1871, 115; Hayden's Eep. Geol. Sur. Montana 1872, 355.

Founded on a lower-jaw fragment with teeth from the Bridger Eocene
Tertiary of Wyoming. Described page 116, and represented in Fig. 44,
Plate VI.

SiNOPA EXIMIA.

Indicated Ijy a lower-jaw fragment, described page 118, and represented
in Fig. 45, Plate VI. From the Bridger Eocene Tertiary of Wyoming.

MuSTELIDiE.

LUTRA I

LUTRA PISCINARIA.

Indicated by a tibia, described page 230, and represented in Fig. 4, Plate
XXXI. From (he Pliocene Tertiary of Idaho.

317

ARTIODACTYLA.

Ruminantia.

Camelid^.

AUCHENIA.

AUCHENIA HESTERNA.

Founded on specimens of teeth described page 255, and represented in
Figs. 1 to 3, Plate XXXVII. From the Quaternary of California.

PROCAMELUS. s. Protocamelus.

Procamelus occidentalis ?

Leidy : Pr, Ac. Nat. Sc. 1858, 23, 89 ; Ext. Mam. K America 1869, 382.

See page 258 of the present work, and represented by Figs. 21, 22, Plate
XX. Pliocene of Nebraska and Texas?

Pkocamelus robustus ?

Leidy: Pr. Ac. Nat. Sc. 1858, 89; Ext. Mam. N. America 1SG9, 381.

See page 259 of the present work. Pliocene of Nebraska and Texas.

Procamelus virginiensis.

Leidy : Pr. Ac. Nat. Sc. 1873, 15.

Page 259, and represented by Figs. 26 to 29, Plate XXVII. Founded on
teeth from the Miocene of Virginia.

Procamelus ? niobrarensis.

Megalomeryx niobrarensis ? Leidy : Pr. Ac. Nat. Sc. 1858, 24 ,• Ext. Mam. Da-
kota and Nebraska 1869, 161, Plate XIV, Figs. 12 to 14.

See page 260, under the name of Megalomeryx niobrarensis ? and repre-
sented in Figs. 24, 25, Plate XXVII. Founded on teeth from the Plio-
cene of the Niobrara River, and from L'Eau qui Court County, Ne-
braska.

CERVIDiS.

LEPTOMERYX.

Leptomeryx Evansl

Leidy : Pr. Ac. Nat. Sc. 1853, 394 ; 1870, 112 ; Ext. Mam. N. America 1869, 383.

Noticed from the Miocene of Oregon, page 216. Originally described
from the Miocene of Dakota,

318

MERYCODUS
Merycodus necatus.

Leidy : Pr. Ac. Nat. Sc. 1854, 90, 157 ; 1857, 89 ; 1858, 23 ; 1870, 109; Ext. Mam.
N. America 18G9, 382.

Noticed from the Pliocene of Sweetwater River, Wyoming. Originally
described from Bijou Hill and from Little White River, or the South
Fork of White Earth River, Dakota.

BoviDiE.

BISON.

Bison latifrons.

Leidy: Pr. Ac. Nat. Sc. 1852, 117 ; Mem. Ext. Sp. American Ox in Smiths. Con-
trib. 1852, 8; Ext. Mam. N. America 18G9, 371.

Noticed from the Quaternary of California and Pennsylvania, page 253, and
represented in Figs. 4 to 8, Plate XXVIII.

Found in the Quaternary of Pennsylvania, Georgia, South Carolina, Ken-
tucky, Mississippi, Texas, and California.

Oreodontid^.

OREODON.

Leidy : Pr. Ac. Nat. Sc. 1851, 238.
Merycoido(lo7i. Leidy : Pr, Ac. Nat. Sc. 1848, 47.

Oreodon Culbertsoni.

Leidy: Owens's Eep. Geol. Sur. 1852,548; Ext, Mara. N.America 1869,379;
Pr. Ac. Nat. Sc. 1870, 67, 112.

Noticed from John Day's River, Oregon, page 211, and I'epresented in
Fig. 12, Plate VII.

Professor Marsh has recently described some remains from the Miocene of
Oregon, under the name of Oreodon occidentalis. (Am. Jour. Sc. May,
1873.) He observes that it resembles O. Culbertsoni in most of its
cranial characters, but differs materially in the large auditory bulltfi.
From this, I suspect the remains, together with those I have described
from Oregon under the last-mentioned name, belong to the species I
have elsewhere named O. hullatus.

Professor Marsh observes that, "in comparing the various species of Oreo-
don, some new points in the structure of the genus were observed." He
then gives in the formula of dentition the number. of incisors as f , canines
T, premolars 4, molars f , and adds : " The caniniform tooth of the lower

319

jaw is clearly tlic first premolar, as Dr. Gill has stated.'' As may be
seen by referring to pages 84 and 85 of the Extinct Mammalia of Dakota
and Nebraska, although giving the formula of dentition of Oreodon as —
incisors f, canines t, premolars I, molars t, I observe that the inferior
canine is a transformed premolar, and that the inferior lateral incisor, as
in other ruminants, is to be regarded as an incisiform canine.

Okeodon superbus.

Leidy : Pr. Ac. Nat. Sc. 1S70, 111.

Described, page 211, and represented by Fig. 1, Plate I; Fig. 16, Plate II;
and Figs. 7 to 1 1, Plate VII. From the Miocene of Oregon.

MERYCOCHCERUS.
Leidy : Pr. Ac. Nat. Sc. 1858, 24 ; Ext. Mam. N. America 18G9, 380.

Merycochcerus rusticus.

Leidy : Pr. Ac. Nat. Sc. 1870, 109.

Described page 199, and represented by Figs. 1 to 3, Plate III ; Figs. 1
to 5, Plate YII; and Figs. 9 to 11, Plate XX. From the Pliocene of
Sweetwater River, Wyoming.

AGRIOCHCERUS.

Agriochcerus antiquus.

Leidy : Pr. Ac. Nat. Sc. 1850, 121 ; Ext. Mam. N. America 1809, 381 ; Pr. Ac.
Nat. Sc. 1870, 112.

Noticed from the Miocene of Oregon, page 216.

Agriochcerus latifrons.

Leidy : Pr. Ac. Nat. Sc. 18G7, 32 ; 1870, G7 ; Ext. Mam. N. America 18G9, 381.

Noticed from the Miocene of Oregon, page 216.

Omnivora.

SuiD^.

DICOTYLES.

DiCOTYLES PRISTINUS.

Peccary. . Leidy : Pr. Ac. Nat. Sc. 1870, 112.

Described page 216, and represented by Figs. 13, 14, Plale VII. From

the Miocene of Oregon.

320

ANTHRACOTHERIDiE.

ELOTHERIUM.

Pomel : Bibl. Uuiv. Geneve, Archives, 1847, 307.

Entelodon. Aymard : Mem. Soc. Agric., &c., dii Pay 1848, 240.

Archa'otherium. Leidy : Pr. Ac. Nat. Sc. 1850, 90.

Elotherium Morton 1 1

Leidy : Pr. Ac. Nat. Sc. 1857, 175 ; Ext. Mam. N. America 1809, 388,
Noticed from Wyoming, page 125, and represented by Figs. 28, 29, Plate
VII.

Elotherium imperator.

Inferred from several mutilated teeth from the Miocene of Oregon, de-
scribed page 217, and represented in Figs. 3, 4, Plate II, and Fig. 27,
Plate VII. • Supposed to be the same as E. superhuin in Pr. Ac. Nat.
Sc. 1870, 112.

Elotherium ingens.

Leidy : Ext. Mam. N. America 1SC9, 388 ; Pr. Ac. Nat. Sc. 1870, 112.

Noticed from the Miocene of Oregon. Orighially from the Miocene of
White River, Dakota.

FAMILIES UNDETERMINED.

HYOPSODUS.

Hyopsodus paulus.

Leidy : Pr. Ac. Nat. Sc. 1870, 110 ; 1872, 20 ; Hayden's Eep. Geol. Sur. Wyo-
ming 1871, 354 ; Hayden's Eep. Geol. Sur. Montana 1872, 363.

To this species, described page 75, I refer Figs. I to 9, 18 to 22, Plate VI.
From the Bridger Eocene of Wyoming.

Hyopsodus minusculus.

This species, described page 81, is represented by Fig. 5, Plate XXVII.
From the Bridger Eocene of Wyoming.

MICROSYOPS.

Leidy : Pr. Ac. Nat. Sc. 1872, 20 ; Hayden's Prelim. Eep. Geol. Sur. Montana

1873, 3G3.
Limnotlierium. In part of Marsh : Am. Jour. Sc. 1871, II, 42.

MiCROSYOPS elegans.

Limnothcrmm cicgans. Mar.sli : Am. Jour. Sc. 1871, 11, 43.
Microsijops gracilis. Leidy : Pr. Ac. Nat. Sc. 1872, 20 ; Hayden's Prelim. Eep.
Geol. Sur. Montana 1872, 363.

321

111 ]\Iicrosyops, six molar teeth imineiliatcly succeed the canine in tlie lower
jaw. In the typical Limnotherium clegans seven molars occupy the same
position. Described page 82, and represented by Figs. 14, 17, Plate VI.
From the Bridger Eocene formation of Wyoming.

MICROS US.

MiCKOSUS CUSPIDATUS. ■

Leitly : Pr. Ac. Nat. Sc. 1870, 113.

Sec page 81 ; not positively determined as a distinct species and genus.
Represented by Figs. 10, 11, Plate VI. From the Bridger Eocene
formation of Wyoming.

HIPPOSYUS.

HlPPOSYUS FORMOSUS.

Leidy : Pr. Ac. Nat. Sc. 1872, 37.

Described from a few isolated teeth, page 90, and represented in Fig. 41,
Plate VI, and Figs. 1, 2, Plate XXVII. From the Bridger Eocene of
Wyoming.

HlPPOSYUS EOBUSTIOE.

Notharctiis rohustior, Leidy : Hayden's Eep. Geol. Sur. Montana 1872, 304.

Described page 93, and represented by Fig. 40, Plate VI. Fnnii the
Bridger Eocene of Wyoming.

HADROHYUS.

HADROnVtlS SUPREMUS.

Leidy : Pr. Ac. Nat. Sc. 1871, 248.

Indicated by a mutilated tooth from the Miocene of Oregon. Described
pa'ge 222, and represented by Fig. 26, Plate XVII.

PERISSODACTYLA,

Sulidungula.

Equid^e.

EQUUS.
Equus major.

Dekay: Nat. Hist. New York, Zool. 1842, 108. Leidy: Ext. Mam. N, America

1869, .399.
Eqmis complicatus. Leidy : Pr. Ac. Nat. Sc. 1858, 11 ; Ext. iMaiii. N. America
1809, 399.

41 G

322

Remains describud iiage 244, and represented by Fii^s. 3 to 18, Plate
XXXIII. From the Quaternary of the United States.

Equus occidentalis.

Leidy : Pr. Ac. Nat. Sc. 1865, 94.
f Equus. Von Me\-er: Palitoutographica 1867, 70.

Equus cxcclsus. Leidy : Pr. Ac. Nat. Sc. 1868, 26 ; Ext. Mam. Dakota and Ne-
braska 1869, 266, 400, Plate XIX, Fig. 39 ; XXI, Fig. 31.
Equus imcifims- Leidy : Pr. Ac. Nat. Sc. 1868, 195 ; Ext. Mam. N. America
1869, 400.

Described page 242, and represented by Figs.. 1, 2, Plate XXXIII. From
the Quaternary I of Nebraska, Idaho, California, and Mexico.

HIPPARION.

HiPPARION SPECIOSUM ?

Leidy: Pr. Ac. Nat. Sc. 1858, 27 ; Ext. Mam. N. America 1869, 401.

See pages 247, 248, and Figs. 14, Ih, Plate XX. From the Tertiary of
Texas.

PROTOHIPPUS, s. MERYCHIPPUS.

Peotohippus perditus (?) s. Merychippus mirabilis ?

Protohippits perditus. Leidy: Pr. Ac. Nat. Sc. 1858, 20; Ext. Mam. N. America

1809, 401.
MerycM]>piis mirabilis. Leidy : Pr. Ac. Nat. Sc. 1858, 27.

See pages 248, 249, 250, and Figs. 16, 20, Plate XX. From the Tertiary
of Texas and Utah.

PrOTOHIPPUS PLACIDUS.

Leidy: Ext. :Mam. N. America 1869, 401.

See pages 249, 250, and Figs. 17, 18, Plate XX. From the Tertiary of
Texas.

Anchitherid^.
ANCHITHERIUM.

Meyer : Jalirlnicli Miueralogie 1844, 298.

Anchitherium Bairdi.

Leidy: Owen's liep. Geol. Sur. Wisconsin, &c., 1852, 572; Ext. Mam. N. Amer-
ica 18G9, 402 ; Pr. Ac. Nat. Sc. 1870, 112.

323

A full account of the remains of tlio species from the Mauvaises Terres of
White River, Dakota, is given in the Extinct Mammalia of Dakota anil
Nebraska, page 303. A notice of remains from Oregon is given page
218 of the present work, and a tooth representing the species is given
in Fig. 15, Plate VII. Miocene.

Anchitheeium Condoni.

Leidy : Pr. Ac. Nat. Sc. 1870, 112.

Described page 218, and represented by Fig. 5, Phitc J I. From the
Miocene of Oregon. .

ANCHITIlERIUiM AGRESTE.

Anchitherium. Leidy: Vr. Ac. Nat. Se. 1871, 101).

Described page 251, and represented by Figs. IG, 17, Plate VII. From

the Miocene ? of Montana.

Anchitherium ? austeale.

Described page 250, and represented l)y Fig. IJ), Plate XX. Fnnn the
Tertiary of Texas.

1 Anchitheehtm.

Uquvs. Leidy : Pr. Ac. Nat. Sc. 18G8, 195.
Uqmis parvulus. Marsh: Am. Jour. Sc. 1808.

Noticed page 252, and represented by Fig. 23, Plate XX. From the
Tertiary of Nebraska.

PAL^OSYOPS.

Leidy: Pr. Ac. Nat. Sc. 1870, 11.3 ; 1871, 111, 118, 197, 229; 1872, 168,211.
" Haydeu's Prelim. Eep. Geol. Sar. Wyoming 1871, 355. Hayden's Prelim. Kep.

Geol. Sur. Moutaiia 1872, 358, published April, 1772.
Telmatherium. Marsh : Am. Jour. Sc. 1872, IV, 123, published iu ad\ance July

22, 1872.
Limnohyns. Mar.sh : Am. Jour. Sc. 1872, IV, 121, published iu advaucc July 22,

1872. Cope: Pr. Am. Phil. See. 1873.

Remains referable to the genus Palteosyops are the most common of Ihosi!
of the larger extinct mammals occurring in the Bridger Eocene formation
of Wyoming. The genus was originally indicated by characteristic spec-
imens of teeth represented in Figs. 4, 5, Plate V, and Figs. 3 to G, Plate
XXIII. Subsequently a numlscr of specimens were received from time
to time and indicated in tiie Proceedings of the Academy from 1870 to
1872, and in Professor Hayden's Preliminary Report of the Geological 8ur-

324

veys of Wyoming and Montana. In the report on Montana, published in
April, 1872, the characters of the genus arc succinctly stated. Pateo-
syops is described "as an odd-toed pachyderm, with the skeleton con-
structed nearly as in the tapir. The thigh-bone possesses a tliird tro-
chanter. The hind feet nearly repeat the construction of those of the
tapir. The skull, with its large temporal fossae, high and thick sagittal
crest, concave occiput, broad, convex face, resembled that of the related
Palaeotherium. The teeth also agree in number and nearly in constitu-
tion with those of that animal. The number of teeth altogether appear
to .have been 44, consisting of 3 incisors, 1 canine, 4 premolars, and 3
molars to the series on each side, above and below. The teeth in each
jaw form a nearly unbroken arch, intervals existing only sufficient to
accommodate the passing of the points of the large and bear-like canines.

"The true molars have a resemblance to those of Palaeotherium. In the
crowns of the upper true molars the inner constituent lobes are
more completely isolated from the outer ones than in that genus, and the
bottoms of the transverse valleys are proportionately of less depth. T//e
last vpper molar of Palceosyops. has hut a single lobe to the inner part of
the a'oio7i. ,

"In Palasotherium, the large premolars have the same form as the true
molars, but are quite different in this respect in Palasosyops. In tlie
iormer the crown of the upper premolars, except the first, is composed
of four lobes, as in the succeeding molars. In Palasosyops the first pre-
molar has a conical crown, the second a bilobed crown, "and the third
and fourth have trilobed crowns.

" The canines of Palaeosyops arc proportionately as large and of the same
form as in the bears "

In an article in the American Journal of Science, 1872, V, published iu
advance July 22, 1872, Professor Marsh, after remarking that the type
of the genus Palaeosyops is too imperfectly known to determine its more
important characters, adds that, "in some ' specimens which agree best
with the original description of paludosus, the last upper molar has tiro
inner cones^ and to this group tlie name Palaeosyops may in future be
restricted. Tlie other specimens have but a single infernal cone on tie
last upper molar, and for the genus thus represented the name Limno-
hyus is proposed."

325

In I his view Professor Cope has recently descrilted some remains of I'aln'-
os3()[is under the name oi' Liiii/whi/us Iceoideiis.

Teeth such as I have attributed to Palaeosyops arc comparatively abundant,
but I have not yet had the opportunity of inspecting a specimen of a
last upper molar, such as Professor Marsh ascribes to Palaeosyops, in
which the inner side of the crown possesses two internal cones. That
such exist there can be no question, as proved by Professor Marsh's
description of Palaeosyops laticeps.

Professor Marsh has described some remains which he refers to a genus
wilh the name of Tehnatherium. Of this, he observes: "The dcniition
of til's genus, so far as is known, appears to be similar to that of PalaBo-
syops. The upper molar teeth have the inner cones more elevf^ted and
more pointed than in Paheosyops, and the Ijasal ridge is well developed
The last upper molar has l)ut a single internal cone." He also remarks
that " the two may be i-eadily distinguished i)y the anterior portion of the
skull, which in Telmatherium has the premaxillaries compressed, with an
elongated median suture. The zygomatic arch is also much less strongly
developed, and the squamosal portion of it is comparatively slender.'' Such
differences are more likely to be of a sexual or individual character than of
either specific or generic value.

Since writing the preceding chapters we have attempted to give a restora-
tion of the skull of Palseosyops in' Fig. 1, Plate XXXI, built up from a
number of specimens. The cranium and face were mainly reconstructed
from the specimens of Fig. 51, Plate XVIII, and Figs. 1, 2, Plate XXIV;
the lower jaw from the specimen of Fig. 52, of the latter plate, and Fig.
4, of the former plate.

1. Pal^osyops paludosus.

Leitly: Pr. Ac. Nat. Sc. 1870, 113 ; 1871,114,197,229; 1S72, 1G8; Hayilcii's

Hep. U. S. Geol. Sur. Wyoiuiug 1S71, 355; llaydeii's itup. U. S. Geo). Sur.

Moutaua 1872, 359.
Pulmosijops. Leidy: Pr. Ac. Nat. So. 1871, 118.
Ijbnnohijus hvvidens. Cope: Pr. Am. Pljil. Soc. 1873, article published in advance

.January 31, 1873.

The description of the species is given on page 28 of the present work.
The specimens represented in Figs. 1 to 8, Plate IV; Figs. 4 to 11,
Plate V ; Figs. 1 to 4, Plate XIX ; Figs. I to 7, Plate XX ; Figs. 3 tp

32(1

G, Plate XXIII; F'ijr.s. C, 7. Plate XXIV; and Fig. 5, Plate XXIX, are

considered as pertaining ti) Palceosj/ops j'aludosus.
A fine specimen, C(nisisti.iig of the greater part of" a skull, exhibited by
Professor Cope to the Academy, and described I)y him under the name
of Limnokyus Icevide.ns, appeared to me to be the same as Palceosyops
paludosus. From the Bridger Eocene formation of Wyoming.

2. Pal.eosyops major.

Leidy: Haydeu's Prelim. Eep. Geol. Sur. Montana, April, 1872,359; Pr. Ac. '
Nat. Sc. 1872, 1G8, L'41. ' •

■ Lymnohyus robustus. Marsh: Ain. Jour. Sc. 1872, IV, 121, published iu advance
July 22, 1872.

I am not convinced that this is a really distinct species from Palceosyops
paludosus. A large number of specimens referable to the genus would
indicate a considerable variation in the size of individnals, of which the
more robust forms may have been males. The species is described on
page 45. The specimens regarded as pertaining to it are represented
in Fig. 8, Plate XX; Figs. 1,2, 7 to 12, 14 to 16, Plate XXIII; and
Figs. 1 to 5, Plate XXIV. From the Bridger Eocene formation of
Wyoming.

3. PaLJEOSYOPS IIUMILIS.

Leidy : Pr. Ac. Nat. Sc. 1872, IGS, 277.

Probably a small species indicated ])y an upper molar, represented in Fig.
8, Plate XXIV, and noticed page 58. From the . Bridger Eocene of
Wyoming.

4. PaL.EOSYOPS JUNIUS.

Paltvosyops junior. Leidy : Pr. Ac. Nat. Sc. li?72, 277.

Descril)e(l page 57. From tlie Bridger Eocene of Wyoming.

LIMNOHYUS.

LiMNOHYUS LATICEPS.

Palmosyops laticeps. Marsh : Aui. Jour. Sc. 1872, 122.

■Indicated page 58, and represented by Fig. 13, Plate XXIII. From the
Bridger Eocene of Wyoming.

327 ■ ■

HYRACHYUS.

Hyuachvus agrarius.

Lekly: naydon'.s rrclim. Rep. Geol. Siir. Wyoming 1871, ;557 ; Pr. Ac. Nat. Sc.

1871, 229 ; 1872, 19, 108; Hayden's Eep. Geol. Siir. Montana 1872, 301.
Hymchyus luiresfis. Leidy : Ilayden's Hep. Geol. Snr. Wyoming 1871, 357.
Lophiodon liairdiimus. Marsh: Am. Jour. Sc. 1S71, II, .">.

Tiie species is (leseribcd page GO of tlie present work, and specimens
attributed to it are represented in Figs. 11, 12, Plate II; Figs. 9 to 18,
Plate IV ; and Figs. 2.5, 2G, Plate XX. From the Bridgcr Eocene of
Wyoniiug.

Hyrachyus eximius.

Leidy: Pr. Ac. Nat. Sc. 1871, 229; 1872,168; Haydcn's Rep. Geol. Sur. Mon-
tana 1872, 301.

Descrilied page- 66, and represented liy Figs. 19, 20, Plate IV ; Fig. 5,
Plate XIX; and Figs. 9, 10, Plate XXVI. From the Bridger Eocene
of Wyoming.

Hyrachyus modestus.

Leidy: Pr. Ac. Nat. Sc. 1872, 20; Hayden's Rep. Geol. Snr. Montana 1872, 301.
LopModon modestus. Leidy : Pr. Ac. Nat. Sc. 1870, 109.

Described page 67, and represented hy Fig. 13, Plate II. From the
Bridger Eocene of Wyoming.

Hyrachyus nanus.

Leidy : Pr. Ac. Nat. Sc. 1872, 20 ; Hayden's Rep. Geol. Sur. Montana 1872, 361.
°? LopModon nanus. Marsh: Am. Jour. Sc. 1871, II, 37.

Described page 67, and represented by Fig. 14, Plate II ; Fig. 42, Plate
VI; Fig. 11, Plate XXVI; and Figs. 21, 22, Plate XXVII. From
the Bridger Eocene of Wyoming.

LOPHIODON ?

LOPIIIODON OCCIDENTALIS.

Leidy : Pr. Ac. Nat. Sc. 1808, 232 ; Ext. Mam. N. America 1809, 391.

Noticed as probably found in the Miocene of Oregon, page 218, and repre-
sented in Fig. 1, Plate II.

LOPHIOTHERIUM.

LOPHIOTHERIIIM SYLVATICUM.

Leidv : Pr, Ac. Nat. Se. 1870, 120.

328

Described pngc 69, and represented by Figs. 33 to 35, Plate VI. From
the Bridger Eocene of Wyoming.

RHINOCEROTIDyE.

RHINOCEROS.
Rhinoceros pacificus.

Leidy: Pr. Ac. Nat. Sc. 1871, 248.

Rhinoceros occidentalis. Leidy : Pr. Ac. Nat. Sc. 1870, 112.

Described from teeth on page 221, and represented by Figs. 6, 7, Plate
II, and Figs. 24, 25, Plate VII. From the Miocene of Oregon.

Rhinoceros hesperiusI *

Leidy : Pr. Ac. Nat. Sc. 1865, 17« ; 1870, 112; Ext. Mam. N. America, 1869, 390.

Originally described from the ramus of a lower jaw from the Miocene 1 of
California. Also supposed to be indicated by teeth described page 220,
and represented by Figs. 8, 9, Plate II, from the Miocene of Oregon.
In the May number of the American Journal of Science for 1873, Professor
Marsh has noticed remains of rhinoceros, which he refers to two addi-
tional species. One named Ji. annectens is founded on remains from the
same formation as those of the preceding species. The other, named
R. oregonensis, is reputed to have pertained to the Pliocene deposits of
Oregon.

families undetermined.

AKCHIPPODUS.

Anciiippodus riparius

Leidy : Pr. Ac. Nat. Sc. 1868, 2.32 ; Ext. Mam. N. America, iu Jour. Ac. Nat. Sc.

1869, VII, 403, Figs. 45, 46, Plate XXX.
Palwosyops minor. Marsli : Am. Jour. Sc. 1871, II, 3C.
TrogosHs castoridens. Leidy: Pr. Ac. Nat. Sc. 1871, 113; Ilay den's Eep. Geol.

Sur. Moutiuia 1872, 360.

Described page 71, under the name of Trogosus castoridcna, and also repre-
sented as such in Figs. 1 to 3, Plate V.

The genus Anchippodus was originally named from an isolated tooth from
a Tertiary formation of Monmouth County, New Jersey. The speci-
men is represented in Figs. 45, 46, Plate XXX, of the seventh volume
of the Journal of the Academy for 1869, and is described on page 403
of that work. It was not nntil after the description of the lower jaw

329

referred to Trogosus caslorldens, ov, page 71 oi' Uie present work, and
represented under the same name in Figs. 1 to 3, Plate V, that I noticed
the identity in character of the corresponding tooth. Previous (o the
descrijition of the jaw referred to Trogosus, Professor Marsh had puh-
Hshed a notice of a simiUir tooth under tlie name of Falcnosyops minor.

It is not improbable, after all, that Trogosus may be distinct from Anchip-
podus, for there are several genera which, while they have the inferior
true molars alike, have the premolars and upper true molars quite differ-
ent. While regarding Trogosus the same as Anchippodus, for the same
reason I have considered Trogosus castoriclens the same' as Anch'qjpoclus
riparlus, for the specimen upon which the latter was originally made known
is identical in form and size with the corresponding tooth in the jaw of
the former. Nor is it improbable that they are the same, for they were
probably of contemporaneous age, and perhaps extended throughout the
continent, as the American mastodon did at a later period. Specimen
from the Bridger Eocene of Wyoming

Anchippodus vetulus.

Trogosus vetulus. Leidy : Pr. Ac. Nat. Sc. 1871, 229; Ilaydeii's Kep. Gcol. Snr.
Moutaua 1872, 3G0.

Noticed on page 75, under the name of Trogosus vetulus, and represented,
with the name of Anchqrpodus vetulus, in Fig. 43, Plate VI. From the
Bridger Eocene af Wyoming.

NGTHARCTUS.

NoTHARCTUS TENEBROSUS.

Leidy: Pr. Ac. Nat. Sc. 1870, 114.

Described page 86, and represented by Figs. 3(i, 37, Plate VI. From tlie
Bridger Eocene of Wyoming.

Proboscidea.

ELEPHAS.

Elepiias americanus.

Dekay : Nat. Hist. New Tork, Zoo]., 1842, 1, 101, Leidy : Ext. Jlaiii. N. America

1869, 398.
Elvphas Golumbi. Falconer: Quart. Jour. Geol. Soc. 1857, .'!19, &{•,.
Elcphas Texiauus. Owen : liep. Brit. Asso. 1858, 84, &c.
Elcphas imperator. Leidy : Pr. Ac. Nat. Sc. 1858, 10.

42 G '

330

• Eucleplias Jaclsoni. Briggs and Foster : Caiiail. Nat. and Geol. 1SG3, 135, 147.
Eitclejjhas Columhi. Falconer: Pahi'ont. Mom. ISGS, II, 211 to 231.
Elcphas. Von Meyer : PaU-coutograpliica, 18G7, 70, Plate VII, Figs. 7, S.

See page 238. Remains noticed from New Mexico and Texas.

MASTODON.

Mastodon americanus.

Leidy: Pr. Ac. Nat. Sc. 1868, 175. For synonymy, see Extinct Mammalia of
North America 1809, 392.

Some remains described or noticed page 237, and represented in Figs. 5,

6, Plate XXII, and Fig. 9, Plate XXVIII.
Remains of the common American mastodon are found \i\ the Quaternary

formation throughout the United States.

Mastodon mirificus.

Leidy: Pr. Ac. Nat. Sc. 1858, 10; 1870, 67; Ext. Mam. Fanna of Dakota and

NebraskalSCO, 249, 390.
Mastodon (Tetralophodon) mirificus. Leidy: Pr. Ac. Nat. Sc. 1858, 10.

Remains originally described from the Pliocene of the Loup Fork of Platte
River. Also reported to occur on the Niobrara River, Nebraska. No-
ticed page 237. From the Pliocene of Sinker Creek, Idaho.

Mastodon obscurus.

Leidy : Ext. Mam. N. America 1809, 390. For earlier synonymy, see the same

work. Pr. Ac. Nat. Sc. 1870, 99; 1871, 199; 1S72, 142.
Mastodon Shepardi. Leidy: Pr. Ac. Nat. Sc. 1870, 98; 1871, 199.
Rhi/nchotheriuln ? See Falconer : Palteontological Memoirs, ISOS, II, 74.

Originally named from remains found in Maryland, North Carolina, and

Georgia. See Extinct Mamnialian Fauna of Dakota and Nebraska,

1869, 244, 396. Remains from California and New Mexico described

page 231 and represented in Figs. 1 to 4, Plate XXI and Figs. 1 to 4,

Plate XXII, of the pres(?nt work, are supposed in whole or part to

belong to the same species. If they do not, they would represent

another species, which might retain the name of 31. Shepardi.

In the. Palaeontographica for 1867, page 64, Von Meyer has given a

description of the right ramus of the lower jaw of a Mastodon, from

Mechoacan, Mexico. The specimen is represented in Plate VI of the

same work, and it contains the last molar and llie one in advance,

both entire. The portion of the last molar tooth in the jaw-fragment

331

iVoni New Jlexico, doscrilx'd page 235, and i('[)ix\seiitcd in Figs. 1, 4,
Plate XXII, bears a veiy near resemblance vvitli the corresponding
part of the same tooth in the Mechoacan specimen. Notwithstanding
this likeness, it woidd appear that the fore part of the jaw differs so
much that tlie two may l)e supposed not to pertain to the same species.
As stated in the account of the New Mexico Mastodon, the anterior
extremity of the jaw is enormously prolonged and provided with a pair
of incisor's. Von Meyer observes of the Mechoacan specimen, "Too
little of the symphysis is preserved to speak with any certainty of its
constitution ; but it appears not to have contained incisors and rather
ended in front in a short beak, as in the elephant." The jaw he I'efers
with doubt to the Mastodon Humholdti.

- I have said that -the New Mexican and Mechoacan specimens may be
supposed not to pertain to the same species. However, when we con-
sider the difference in the fore part of the lower jaw of the sexes in
the Mastodon americanus, it is not improbable that the male of the
Mastodon Shepardi may have had the lower jaw provided with a long
beak and incisors which might have been absent in the female.

'&"

UINTATHERIUM.

Titanotlierium. Marsli : Am. Jour. Sc. 1S71, II, 35 ; the article published in
advance Juue 21, 1871 ; ibid. 1872, IV, 123, ijublished iu advance July 22,
1872.

Mastodon. Marsh: Am. Joui-. Sc. 1872, note to p. 123, published iu advance
July 22, 1872.

UlNTATHERIUM.

Leidy: Pr. Ac. Nat. Sc. 1872, 1G9 ; in a letter addressed to the Academy and
published in advance of the proceedings August 1, 1872. Reprinted in Am.
Jour. Sc. September, 1872, 239. Pr. Ac. Nat. Sc. 1872, 241. Marsh: Pr. Am.
Phil. Soc. 1872, 578; Am. Jour. Sc. 1873, V, 118; American Naturalist
1873, 147. Cope: Pr. Ac. Nat. Sc. 1873, 10, 102; Pr. Am. Phil. Soc. Feb.,
1873. Nature : March 13, 1873, 3GG.

Uititamastix. Leidy : Pr. Ac. Nat. Sc. 1872, 169.

Tinoceras. Marsh: Am. Jour. Sc. 1872, IV, in errata of Sept. No.; do., p. 504,
published in advance August 19, 1872; ibid. 1872, IV, 322, published in
advance August 24, 1872 ; ibid. 1872, IV, 323. published iu advance Sep-
tember 21, 1872; ibid. 1872, IV, 343, published in advance September 27,
1872; ibid. 1873, V, 117, published in advance January 28, 1873; ibid. 1873,
V, 293, published iu advance March' 18, 1873; American Naturalist Jan.,
1873, 52.

Eohttsileus. Oojn' :* Pr. Am. riiil. Soc. 1872, 4.S5, pxiblisbed in advance August
L'O, 1872; ibid. 1872, 512; ihiil. 1873, published as a separate pamphlet, "On
the Short-Footed Ungulata of the Eocene of Wyoming," March 11, 1873 ; Pr.
Ac. Nat. So. 1873, 10, 102 ; American Naturalist, March 1873, 180.

LoxoJophodon. Cope : Pr. Am. Phil. Soc. 1872, 487, 488, published in advance
August 22, 1872. Here regarded as the same genus tirst named in the Pro-
ceedings of February 16, 1872, 420, and founded on the tooth of an animal
about the size of the American tapir, referred to Bathmodon semicinctus and
then to Loxolophodon. Pr. Am. Phil. Soc. 1872, 580 ; Pr. Ac. Nat. Sc. 1873,
102.

LcfalopUodon. Typograpliical error? Cope: Pr. Am. Phil. Soc. 1872, 515.

IHnoccras. Marsh : Am. Jour. Sc. 1872, IV, 344, published in advance September

27, 1872; iUd. 1873, V, 117-122, Plates I, II, published in advance January

28, 1873 ; ibid. April, 1873, published in advance March 18, 1873 ; American
Naturalist, March 1873, 146. Nature, March 13, 1873, 3GG.

Loxolophodon. Cope: " Ou the Short-Footed Ungulata of the Eocene of
Wyomiug," read before the Am. Phil. Soc, Feb. 21, 1873, and published in
advance of the Proceedings, March 14, 1873. The name is here used as that
of a genus recognized as distinct from the one originally described wuler tlie
same name, which the author now regards as a synonym of Bathmodon.

All the above names I suspect to have been applied to members of the
same genus, and in this view have regarded them as synonyms to the
first characteristic generic name employed. Of this, however, I am by
no means positive, as I have had no opportunity of examining the
difterent fossils upon which the genera were founded, except those
described by myself under the name of Ulntatherium robustum, and the
skull described by Professor Cope under the name of Loxolophodon cornutus.

In addition, we have the description and figures of the skull described by
Professor Marsh under the name of Dinoceras inirabilis.

As far as I am al)lc to estimate the differences which have been indicated
by the authors just named and those observed by myself, they appear to be
rather of specific value, and perhaps in part of sexual character, than of
generic importance. We hope, however, that all obscurity in relation to the
matter will be cleared away when Professor Marsh and Professor Cope
present to ns full descriptions with characteristic figures of the fossils in
their possession. I may add it is not improbable that the names of
Uintatherium, Tinoceras, Eobasileus, Dinoceras, and Loxolophodon, may be

* The dates given as those of Professor Cope's publications in advance of the dif-
ferent periodicals named are taken from the jiublications themselves; but they are,
in some instances, contested by Professor Marsh. See an article read before the
Philadelphia Academy of Sciences April 8, 1873, and published by Professor Marsh'
under the title " On the Dates of Professor Cope's Recent Publications."

c.x|}ressivu of more llian one genus, in the light that Ciiriacus, Capreohis,
Blastocerus, Axis, Elaphus, &c., are distinct from Cervus. Future compari-
sons and discoveries will perhaps reduce the nine s|)ecies of the five genera
wliich have been indicated to the number of two or three species of one or
two genera.

Professor Marsh has referred the remarkable animals above indicated to a
new order with the name Dinocerata. In the uncertainty as to the true
ordinal position of Uiutatherium, I have allowed it to remain, according to
my tirst impression, with the Proboscidea.

UlNTATHEEIUM ROBUSTUM.

Leidy : Pr. Ac. Nat. Sc. 1872, 1G9, iu a letter addressed to the Academy and
published in advance of the proceedings, August 1, 1872. Keprint ot the
letter in Am. Jour. Sc. September, 1872, 239. Pr. Ac. Nat. Sc. 1872, 241.
Cope: Pr. Ac. Nat. Sc. 1873, 102; Pr. Am. Phil. Soc. 1873. Marsh: Am.
Jour. Sc. 1873, V, 290 ; American Naturalist, January, 1873'.

Uintamastiv atrox. Leidy : Pr. Ac. Nat. Sc. 1872, 169 ; Am. Jour. Sc. 1872, 239.

Binocems mirabUls. Marsh : Am. Jonr. Sc. 1872, IV, 344, published iu advance
September 27, 1872; ibid. 1873, V, 117-123, Plates I, II, published in advance
January 28, 1873; Ibid. April, 1873, published iu advance March IS, 1873.
American Naturalist, March, 1873, 140. Nature, March 13, 1873, 300.

Uintathcrium mirahile. Cope : Pr. Ac. Nat. Sc. 1873, 102 ; Pr. Am. Phil. Soc.
1873, published iu advance " On the Short-Footed Ungulata of the Eocene of
Wyoming, March 14, 1873, 28."

The Figs. 6 to 12, Plate XXV, Figs. 1 to 3, Plate XXVI, and Figs. 30 to 34.
Plate XXVII, of the present work, represent the chief type-specimens upon
which the genus Uintatherium was founded and the species U. robustum
named. Descriptions of these occur on pages 93 and 96.

The large canine tooth represented in Figs. 1 to 5, Plate XXV, was, on
discovery, supposed to belong to a Drepanodon-like carnivore. The dis-
covery of the nearly complete skulls described by Professor Marsh under the
name of Dlnoceras ?nirabilis, and Professor Cope under the name of Loxolo-
yhodon cornutus, leaves no doubt that the remarkable tooth l)elongs to the
same kind of an animal, which, from the proportions of the specimen, I sup-
pose to be Uintatherium robustum.

The tine skull discovered and described by Professor Cope under the name
of Lo.rolophodon cornutus, I had the opportunity of seeing on the occasion
when it was exhibited at a meeting of the Academy of Natural Sciences.
So fiir as I could judge from the cursory examination, and from the more

334

recent description and figures of the skull, it appears to me to be a larger
s2)eciesof Uintatherium than the U. rohustum, l)ut not of a distinct genus.

The remains, which were first noticed by Professor Marsh and referred to
Titanotherium (?) anceps, subsequently to Mastodon anceps, and finally to
Tinoceras anceps, I have not seen. I have suspected that perhaps they
might pertain to the same animal as that I have described as Uintatlierium
rohustum. Should this prove to be the case, as the specific name of anceps
is of earliest date, the latter woukl be correctly designated as Uintatherium
anceps.

Professor Marsh regards the Eohasileus s Loxolophodon cornutus, Cope, as
pertaining to Tinoceras, probably T. grandis, Marsh, (Am. Jour. Sc. April,
1873.) On the other hand Professor Cope refers Dinoceras to Uintatherium,
and also includes as synonyms Titanotherium (?) anceps, and therefore Tinoceras,
Marsh, (Pr. Am. Phil. Soc. 1873.) Thus the conjoint views of these authors
rather favor the idea that all are probably of the same genus.

Since the article on Uintatherium rohustuin, page 96, was printed, I have
attempted a restoration of the skull in Fig. 1, Plate XXVIII, on an enlarged
outline taken from Professor Marsh's Fig 1, Plate II, of Dinoceras mirahilis,
published in the American Journal of Science for February, J 873. The
ci'anial fragment and that of the upper jaw with the last molar tooth are
taken from the same skull as the specimens of Fig. 8, Plate XXV, and
Fig. 1, Plate XXVl. The canine is from the same specimen as Fig. 1, Plate
XXV.

In the May number of the American Journal of Science for 1873, Pro-
fessor Marsh has indicated what he considers to be a new species of Dinoceras
with the name of Z>. lucaris. In the account he observes, " From Uintatherium,
so far as that genus is at present known, Dinoceras differs in the jJosition of
the occipital condyles, in the more anterior position of the posterior horns,
and. in the last molar, which lacks the external cone between the two trans-
verse ridges, and has a second small tubercle behind the posterior ridge."
These characters may, perhaps, together with others more important, point
to a different species, but appear hardly sufficient to distinguish a genus.
The differences are also more apparent than real ; for instance, the so-called
"external cone between the two transverse ridges" of the last molar, as seen
in Fig. 7, Plate XXV, is nothing more than a tubercle produced from the
basal ridge, might be absent iu another individual, and is actually so in the
molar in advance, as seen in Fig. 12 of the same Plate.

335

MEGACE^OPS* s. Megacemtops.
Megacerops qoloradensis.

Leidy : Pt. Ac. Nat. Sc. 1870, 1 ; Haydeu's Reii. Geol. Sur. Wyomiug, 1871, 352.
Megaceratops color adoensis. Cope: Pr. Ac. Nat. Sc. 1873, 102; Pr. Am. Phil.
Soe. 1873.

Described page 239, and represented by Figs. 2, 3, Plate I, and Fig. 2,
Plate II.

Before the discovery of the more characteristic specimens of the skulls of
species of Uiiitatheriuni, from the nearer resemblance of the fossil described
under the name of Megacerops to the corresponding part of Sivatherium,
the animal to vvliicli it belonged was supposed to be a ruminant. It now
appears probable that Megacerops forms a member of the same order, what-
ever that may l)e, with Uintatherium.

Rodentia.

SciURIDyE.

PARAJHYS.
Paramys delicatus.

Leidy: Pr. Ac. Nat. Sc. 1871, 231; Ilaydeii's Kep. Geol. Sur. Montana, 1872,
357.

Described page 110, and represented hy Figs. 23 to 25, Plato VI. From

the Bridger Eocene of Wyoming.

Paramys delicatior.

Leidy : Pr. Ac. Nat. Sc. 1871, 231 ; Haydeu's Rep. Geol. Sur. Montana, 1872, 357.
Described page 110, and represented by Figs. 26, 27, Plate VI, and Figs.
16 to 18, Plate XXVII. From the Bridger Eocene of Wyoming.

Paramys delicatissimus.

Leidy: Pr. Ac. Nat. Sc. 1871, 231 ; Hayden'sEep. Geol. Sur. Montana, 1872,357.
Described page 111, and represented by Figs. 28, 29, Plate VI. From
the Bridger Eocene of Wyoming.

SCIUPtAVUS !

Marsli : Am. Jour. Sc. 1871, 122.
A tooth supposed to pertain to this genus is described on page 113, and
represented in Fig. 30, Plate VI. From the Bridger Eocene of Wyo-

* For the sake of l)oth brevity and euphony, I have preferred to use Jlegaccrops
instead of Megaeeratoiis, ju.st as Megatherium is preferred toMegalolheriiun, &c.

336

MuEIDiE. (?)

MYSOPS.

Mysops minimus.

Leidy: Pr. Ac. Nat. Sc. 1871, 232; Hayden's Eep. Gcol. Sur. Moutaua, 1872,
357.
Described page 111, and represented bj Figs. 31, 32, Plate VI. From the
Bridger Eocene of AVyoming.
Mysops fkaternus.

Described page 112, and represented by Figs. 14, 15, Plate XXVII.
From the Bridger Eocene of Wyoming.

Insectivora.

FAMILIES UNDETEKMINED.
OMOMYS.

Omomys carteri.

Leidy: Pr. Ac. Nat. Sc. 18G9, G3.
Originally described in the Extinct Mammalia of Nortli America, 1S69,
408, and represented in Figs. 13, 14, Plate XXIX of the same work.
Redescribed in the present work, 120. From the Bridger Eocene of
Wyoming.

PAL^ACODON.

PALiEACODON VERUS.

Leidy : Pr. .Ac Nat. Sc. 1872, 21 ; Hayden's Eep. Geol. Sur. Montana, 1872, 356.
Described from specimens of teeth page 122, and represented by Fig. 46,
Plate VI. From the Bridger Eocene of Wyoming.

WASHAKIUS.

Washakius insignis.

Described page 123 from a small jaw-fragment containing the last two
molars, and represented in Figs. 3, 4, Plate XXVII. From the Bridger
Eocene of Wyoming.

Sirenia.
MANATUS.

Makatlis inoknatus.

Figs. 16, 17, Plate XXXVII, represent the crown of a tooth from the
" phosphate l>eds'' of the Ashley River, South Carolina. It most nearly

337

resembles the corresponding part of the lower teetli of the living Manatee of
the Florida coast, and it indicates an animal of about the same size. Tlie
constituent lobes of the crown are less contracted approaching the summits,
and the intervening valleys are wider than in the teeth of the living Manatee.
The summits of the lobes being less contracted, are also sliarper and not so
wrinkled. The summit of the anterior lobe presents a wider and deeper
oval pit, and the posterior heel is less mammillary, not wrinkled at the sum-
mit, and is broadly sloping at its fore part. The crown measures half an inch
four and aft and 4J lines where widest.

Zeuglodontia.

PONTOBASILEUS.

PONTOBASILEUS TUBERCULATUS.

Fig. 15, Plate XXXVII, represents a fragment of a remarkable tooth,
apparently belonging to an animal of the same order as the Basilosaurus.
The specimen pertains to the Museum of the Academy of Natural Sciences
of Philadelphia. It is without label, and was associated with some Basilosaurus
remains from Alabama. I suppose it to have been derived from some Eocene
or Miocene formation of the Atlantic States. Upon the fang there are the
remains of two white disks, apparently the basal attachment of barnacles.

The fragment consists of the back portion of the crown and the corre-
sponding fang of a double-fanged tooth. The crown has been very unlike
that of any known animal of the order. The conical summit occupied a
position over the separation of the fangs, including at most the anterior one.
The back part of the crown forms a wide, thick heel, extending over more
than half the width of the corresponding faug. The enamel is exceedingly
tuberculate, and near the most prominent portion of the heel outwardly it is
worn off over a small oval space from attrition of an opposed tooth. The
fang is widely divergent, and is depressed along the middle externally and
internally, and also more deeply on the surface opposed to the absent fang.

Cetncea.
Delphinid^.

GRAPHIODON.
Graphiodon vinearius.

Leidy : Pr. Ac. Nat. So. 1870, 122.
An extinct genus and species ol' cetacean animals, apparently dilFerent
43 o

338

from any previously described, is indicated by a fossil submitted to my
examination l^y the Smithsonian Institution. The specimen was found by
Mr. Pearce in the Miocene formation of Gay Head, Martha's Vineyard. It
consists of a tooth represented in Fig. 7, Plate XXII, of the natural size.

The form of the tooth, with its huge gibbous fang, led me at first to mis-
take it for that of a mosasauroid reptile, nor did I observe my error until it
was suggested by Professor Marsh

The crown of the tooth is curved, conical, and without subdivisional planes
upon the surface. The inner and outer surfaces are barely defined i^ostero-
internally by a feeble and interrupted ridge. The enamel is singularly
wi-iukled, the wrinkles being short, vermicular, somewhat branched and
crowded, and they remind one of Arabic letters. At the base of the crown
the enamel is nearly smooth. The transverse section of the crown is cir-
cular, and measures 8 lines in diameter. The length of the crown when
complete appears to have been about twice the latter.

The fang of the tooth, broken at the extremity, exposes to view a large
interior pulp cavity. It is longer than the crown and very gibbous. In its
relation of size and form, it is wonderfully like the corresponding part in the
teeth of Mosasaurus. It is ovoidal in tbrm and is curved in the dii'ection of
the crown. It is abruptly thickened at the base of the latter, and on one
side, near-the extremity, exhibits a deep groove. The texture of the fang, as
seen at its broken part, appears as dense as ordinary dentine. In the entire
condition, the fang has approximated 2 inches in length ; its diameter is
about half the length.

REP T ILIA.

Dinosauria.

POICILOPLEURON.

Deslongchamps : Mem. Soc. Liu. de Normandie VI, 1838, 37.

POICILOPLEURON VALENS.

Leidy : Pr. Ac. Nat. Sc. 1870, 3.
Antrodemus. Leidy : Ibidem, 4.

Founded on several fragments of vertebree described page 267, and rep-
resented by Figs. 16 to 18, Plate XV, under the name of Antrodemus.
From Colorado, and supposed to have been derived from the Cretaceous
formation.

339
Chelonia.

TESTUDINIDiE.

TESTUDO.

Testudo Coesoni.

Leidy: Pr. Ac. Nat. Sc. 1871,154; 1872,268; Hayden's Eep. Geol. Siir. Mon-
tana, 1872, 3GG.

Emys Carteri. Leidy: Pr. Ac. Nat. Sc. 1871, 228; Hayden's Eep. Geol. Sur.
Montana, 1872, 3G7.

Described page 132, and represented in Figs. 1, 2, Plate XT, under the
name of Emys Carteri ; in Fig. 7, Plate XV ; Figs. 2 to 4. Plate XXIX,
and Figs. 1 to 4, Plate XXX. From the Bridger Eocene of Wyoming.

Testudo nebrascensis.

Leidy : Pr. Ac. Nat. Sc. 1852, 59 ; Owen's Eep. Geol. Sur. Wisconsin, &c. 1852,

567 ; Ancient Fauna of Nebraska, 1853, 103, Plate XIX ; Ext. Mam. Fauna

of Dakota and Nebraska, 1869, 20.
Stylemys nebrascensis. Leidy : Pr. Ac. Nat. Sc. 1851, 172 ; Ancient Fauna of

Nebraska, 1853, 103 ; Ext. Mara. Fauna of Dakota and Nebraska, 1869, 26.

See page 223. Cope: Ext. Batracbia, &c. 1870, 121.
Emys s. Testudo hemisjiherica, Owciti, Ciilbertsoni, et lata. Leidy: Pr. Ac. Nat. Sc.

1851, 173, 327 ; 1852, 34, 59. Owen's Eep. Geol. Sur. Wisconsin, &c. 1852,

568 to 572; Ancient Fauna of Nebraska, 1853, 105 to 110, Plates XX to

XXIV.
Stylemys Gulbertsonii. Cope : Ext. Batracbia, &c. 1870, 124.

Noticed page 224 under the name of SUjlemys nebrascensis, ;iud further
represented by Figs. 7, 9, 10, Plate XIX.

All the turtle i-emains from the Mauvaises Terres of White River, Dakota,
which have come under my inspection, and which have been described under
the various names above indicated, I regard as having pertained to a single
species. This agrees so closely in the usual characters of living species of the
land tortoises, that I have placed it in the same genus, though it is subgeneri-
cally distinct. A mature and nearly perfect specimen of the shell in the
Museum of the Academy of Natural Sciences, obtained by Professor Hayden
in 1866, has the following dimensions :

laches.

Length of carapace in the curve : 27

Breadth of carai)ace in the curve 26

Length of plastron 20

Breadth of plastrou 15

Height of shell above the level 8

340

Testudo niobraeensis.

Testiulo (Stylcmys) niohrarensis. Leidy : Pr. Ac. Nat. Sc. 185S, 29 ; Ext. Main.

Fauua Dakota and Nebraska, 1SG9, 20. See page 224.
Stylemys niohrarensis. Cope : Ext. Batracliia, &e. 1870, 124.

Described page 225, under the name of Slylemys niohrarensis, and repre-
sented by Figs. 4 to (5, Plate III, and Figs, fi, 8, Plate XIX. * From the
Pliocene of the Niobrara River.

Testudo okegonensis.

Stylemys oregonensis. Leidy : Pr. Ac. Nat. Sc. 1871, 248. See page 225.
Noticed page 226, under the name of Stylemys oregonensis, and repre-
sented by Fig. 10, Plate XV. From the Mioceiie of Oregon. I suspect
I have been too hasty in regarding this as a species distinct from Testudo
nebrascensis.

Emydidte.

EMYS.

Emys wyomingensis.

Leidy : Pr. Ac. Nat. Sc. 18G9, G6 ; Haydeii's Kep. Geol. Sur. Montana, 1872, 367.
Emys Sfcvensonkmus. Leidy : Pr. Ac. Nat. Sc. 1870, 5 ; Hayden's Eep. Geol.
Sur. Wyoming, 1871 , 3GG.

Umys Jeanesi. Leidy : Pr. Ac. Nat. Sc. 1870, 123 ; Haydeu's Eep. Geol. Sur.

Wyoming, 1871, 3GC.
Umys Haydeni. Leidy : Pr. Ac. Nat. Sc. 1870, 123 ; Hayden's Eep. Geol. Sur.

Wyoming, 1871, 3GG.

The species described page 140, and represented by Figs. 2 to 6, Plate
IX, Figs. 1, 2, Plate X. From the Bridger Eocene of Wyoming.

Emys peteolei.

Leidy : Pr. Ac. Nat. Sc. 18GS, 17G. Cope : Ext. Batraebia, &c. 1870, 128.
Species described page 260, and represented by Fig. 7, Plate IX. From
the Quaternary of Texas.

IIYBEMYS.

IIyijemys aeenakius.

Leidy: Pr. Ac. Nat. Sc. 1871, 103.
Noticed page 174, and represented by Fig. 9, Plate XV. From the
Bridger P^ocene of Wyoming.

341

FAMILIES UNDETERMINED, APPARENTLY INTERMEDIATE TO THE PLEURODIRIDiE

AND THE CHELYDRID/E,

BAPTEMYS.

Baptemys wyomingensis

Leicly : Pr. Ac. Nat. Sc. 1870, 4 ; Haydeu's Ecp. Geol. Siir. Wyomiilg, 1S71, 367 ;

Haydeu's Rep. Geol. Sur. Montaua, 1872, 307.
Adocus injoiniDffeniih. Cope: Pr. Am. Piiil. Soc. 1870, 297; Ext. Batracliia,

Eeptilia N. Am. in Trau.s. Am. Phil. Soc. 1870, 233.

Described page 157, and represented by Figs. 1, 2, Plate XII, and Fig. 6,
Plate XV. From the Bridger Eocene of Wyoming.

CHISTERNON s. Chisternu?n.

Leidy : Pr. Ac. Nat. Sc. 1872, 102.

ChISTERNON UNDATL'M.

Baena undata. Leidy : Pr. Ac. Nat. Sc. 1871, 228 ; Haydeu's Rep. Geol. Sur.
Montana, 1871, 3G9.

Described page 169, and represented by Figs. 1, 2, Plate XIV, under tlie

name of Baena undata. From the Bridger Eocene of- Wyoming.

Chisternon undatum, in the presence of an additional pair of plates to the

plastron, resembles the existing SternotliEerns.

BAENA.
Baena arenosa.

Leidy : Pr. Ac. Nat. Sc. 1870, 123 ; 1871, 228 ; Hayden'.s Rep. Geol. Snr. Wyo-
ming, 1871, 307 ; Haydeu's Rep. Geol. Sur. Montana, 1872, 308.
Baena affinis. Leidy : Haydeu's Rep. Geol. Sur. Wyoming, 1871, 307.

Species described page 161, and i-epresented by Figs. 1 to 3, Plate XIII,

under the names of Baena arenosa and Baena affinis, Figs. 1 to 5, Plate

. XV, and Figs. 8, 9, Plate XVI.

ANOSTEIRA.

Anosteira ornata.

Leidy : Pr. Ac. Nat. Sc. 1871, 102, 114 ; Haydeu's Rep. Geol. Sur. Wyoming, 1872,
370.

Described page 174, and represented by Figs. 1 to 6, Plate XVI. From

the Bridger Eocene of AVyoniing.

Trionychid^.

TRIONYX.

Trionyx guttatus.

Leidy : Pr. Ac. Nat. Sc. 18G9, 00 ; 1870, 5 ; 1871, 228 ; Haydeu's Rep. Geol. Sur.
Wyoming, 1871, 367; Haydeu's Rep. Geol. Sar. Montana, 1872, 370. Cope:
Ext. Batracliia, &c., 1870, 152.

'342

Desci-ibed page 176, and represented by Fig. 1, Plate IX. From the
Bridger Eocene of Wyoming.

Trionyx uintaensis.

Leidy : Pr. Ac. Nat. Sc. 1872, 267.
Described page 178, and represented by Fig. 1, Plate XXIX. From the
Bridger Eocene of Wyoming.

Teionyx ?

Fragments descriljed page 180, and represented in Figs. 11, 12, Plate
XVI. From the Bridger Eocene of Wyoming.

SPHAEGIDIDiE 1

ATLANTOCHELYS,

Atlantochelys mortoni.*

Agassiz : Pr. Ac. Nat. Sc. 1849, 169.

Momsaurus Mitchelli. Leidy: Cret. Eept. in Siuitli. Coiitrib. 1865, 43, 116. De-

termiuation admitted by Cope: Pr. Bost. Soc. Nat. Hist. 1869, 253.
Protostega neptunia. Cope ; Pr. Am. Phil. Soc. 1872, 433.

Fonnded on the fragment of a large humerus described in the " Cretaceous
Reptiles of the United States," 1865, 43, and represented in Figs. 3, 4,
5, Plate VIII of that work. From the Cretaceous green sand of New
Jersey. See page 270.

Atlantochelys tuberosus.

Holcodus acutidess. lu part of Leidy : Cret. Eept. iu Smiths. Contrib. 18C5, 42,

118. Determination admitted by Cope : Pr. Bost. Soc. Nat. Hist. 1869, 253.

Platecarpus tympaniticus. In part of Cope : Pr. Bost. Nat. Hist. Soc. 1869, 265 ;

Syuop. Est. Batrachia, Reptilia, &c. 1870, 199.
Protostega. Cope: Pr. Am. Phil. Soc. 1872, 433.
Platecarpus tuberosus. Cope: Pr. Am. Phil. 1872, 433.
Protostega. tuberosa. Cope : Hayden's Eep. Geol. Sur. Montana, 1872, 330, 334.

Founded on a humerus described in the "Cretaceous Reptiles of the
United States," 1865, 42, and represented in Figs. 1, 2, Plate VIII of
that work. From the Cretaceous formation near Columbus, Mississippi.
See page 270.

It was the association of this specimen with several cervical vertebras, and

* Professor Cope observes that "this name was unaccompanied with the necessary
description, and is hence useless to science." (Pr. Am. Phil. Soc. 1872, 433.) As the
specimen on which it was founded was described and figures in my paper on the Cre-
taceous Eeptiles, so as to be recognized by every student, I have preferred to employ
the original name instead of the proposed substitute.

343

a palatine bone with teeth of an nndoubted niosasaiiroid, that led me'^into the
error of snpposing it belonged to the same animal. This suggested the idea
that the specimen originally referred to Atlantochelys Mortoni likewise be-
longed to a Mosasauriis. The error was easy at a time when the limb-bones
of none of the mosasanroids were known, ;uul when it was even doubted
whether these rejjtiles possessed hinder lind)s. My determination was con-
curred in, not only by Professor Cope, but also Ijy Prcdessor Agassiz, after I
had exhibited to him the different specimens and their associates.* It was
only after I had had the opportunity of seeing the nearly complete fore-limbs
in the skeleton of Clidastes pro]iijthon, described by Professor Cope, that
I suspected my reference of the specimens of humeri above indicated was
incorrect.

CYNOCERCUS?

Cynocercus incisus. ■?

Cope : Pr. Am. Phil. Soc. 1872, 309.

Remains probably belonging to this species described page 2G9, and
represented by Figs. 17 to 21, Plate XXXVI. From the Cretaceous
of Kansas.

Mosasauria.
MOSASAURUS ?

MOSASAURUS %

See page 279. Represented by Fig. 15, Plate XXXVI. From the Cre-
taceous of Nebraska.

TYLOSAURUS.

Tylosaurus dyspelor.

Marsh : Am. Jour. So. 1872, 147.

Liodon dyspelor. Cope : Pr. Am. Phil. Soc. 1870, 572, 574 ; 1871, 109, 280 ; Hay-
den's Eep. Geol. Sur. Wyoming, 1871, 410 ; Haydeii's Rep. Gcol. Snr. Montana,
1872, 333.

Rhinosaurus dyspelor. Mar.sh : Am. Jour. So. 1872.

BUampliosaurus. Cope : Pr. Ac. iSTat. Sc. 1872, 141.

See page 271. Represented by Figs. 1 to 11, Plate XXXV. From the
Cretaceous of New Mexico and Kansas.

* I do not introduce the names of these naturalists as an apology for my error, but
rather to show that able authorities are liable to the same mistaices under tlie same
circumstances.

344

Tylosaurus peoriger.

Marsh : Am. Jour. Sc. 1872, 147.

Macrosaurus j)roriger. Cope: Pr. Ac. Nat. Sc. 1869, 123.

Liodon proriger. Cope: Trans. Am. Phil. Soc. 1870, 202; 1871, 279; Haydeu's

Eep. Geol. Sur. Wyoming, 1871, 401 ; Hayden's Eep. Geol. Sur. Montana, 1872,

333.
Ehinosaitriis jiroriger. Marsh: Am. Jour. Sc. 1872.
Ehampliosaurus. Cope : Pr. Ac. Nat. Sc. 1872, 141.

See page 274. Represented l)y Figs. 12, 13, Plate XXXV, and Figs. 1 to

m the Cretaceous oi

LESTOSAURUS.

3, Plate XXXVI. From the Cretaceous of Kansas.

Lestosaurus coryph^us.

Maish : Am. Jour. Sc. 1872.

Holcodus corypliicus. Cope : Pr. Am. Phil. Soc. 1871, 269 ; Hayden's Rep. Geol.

Sur. Montana, 1872, 331 .
f Platecarpns. Cope: Pr. Ac. Nat. Sc. 1872, 141.

See page 276. Represented by Figs. 12 to 14, Plate XXXIV, and Figs.
4 to 14, Plate XXXVI. From the Cretaceous of Kansas.

CLIDASTES.

Cope : Pr. Ac. Nat. Sc. 1868, 2.33.

Clidastes intermedius.

Leidy : Pr. Ac. Nat. Sc. 1870, 4. Cope : Syu. Ext. Batrachia, Reptilia, &c.
1870, 221 ; Hayden's Rep. Geol. Sur. Wyoming, 1871, 412.

Described page 281, and represented by Figs. 1 to 5, Plate XXXIV. From
the Upper Cretaceous of Alabama.

Clidastes affinis.

G. intermedius. lu part, Leidy : Pr. Ac. Nat. Sc. 1870, 4.

Described page 283, and represented by Figs. 6 to 11, Plate XXXIV.
From the Cretaceous of Smoky Hill River, Kansas.

Lacertilia.-

SANIWA s. Saniva.

Saniwa ensidens.

Leidy : Pr. Ac. Nat. Sc. 1870, 124 ; Hayden's Rep. Geol. Sur. Wyoming, 1871,
368 ; Haydeu's Rep. Geol. Sur. Montana, 1872, 370.

Described page 181, and represented by Fig. 15, Plate XV, and Fig_ 3.5,
Plate XXVII. From the Bridger Eocene of Wyoming.

Saniwa major.

Described page 182, and represented by Fig. 14, Plate XV, Figs. 36, 37,
Plate XXVII. From the Bridger Eocene of Wyoming.

CHAMELEO.

ClIAMELEO PRISTINUS,

Leidy : Pr. Ac. Nat. Sc. 1872, 277.

Described page 184, and represented by Figs. 38, 39, Plate XXVII.
From the Bridger Eocene of Wyoming

G-LYPTOSAURUS.

Marsh : Am. Jour. Sc. 1871 ; Pr. Ac. Nat. Sc. 1871, 105.

Glyptosaurus 1

Noticed page 182, and represented by Fig. 13 to 17, Plate XVI. From
the Bridger Eocene of Wyoming.

TYLOSTEUS.

Tylosteus ornatus.

Leidy: Pr. Ac. Nat. Sc. 1872, 40.

Noticed page 285, and represented by Figs. 14, Plate XIX. From the
Upper Missouri ; probably Cretaceous.

Sauropteri/gia.
NOTHOSAURUS.

NOTHOSAURUS OCCIDUUS.

Nothosaurops occiduus. LeiOy : Pr. Ac. Nat. Sc. 1870, 74.

Noticed page 287, and represented by Figs. 1 1 to 13, Plate XV. From
the Cretaceous 1 of Moreau River, Dakota.

OLIGOSIMUS.

■OlIGOSIMUS GRANDiEVUS.

Leidy : Pr. Ac. Nat. Sc. 1872, 39.

Described page 286, and represented hy Figs. 18, 19, Plate XVI. From
the Cretaceous (?) of Wyoming.
44 G

FISHES.

Teleostei.

Labrid^.

PROTAUTOGA.
Protautoga conidens.

Tautoga (Protautoga) conidens. Leidy : Pr. Ac. Nat. Sc. 187.3, 15 ; Am. Jour. Sc.
1873, 312.

A short time since, Mr. C M. Smith, engineer, of Richmond, Virginia,
submitted to the writer, for examination, a small collection of fossil bones,
which had been discovered by him during the construction of a tunnel
beneath the city. Mr. Smith informs me that the material penetrated by
the tunnel, in which the bones were found, consists of a stiff blue clay con-
taining remains of infusoria. Oh examining a portion of the substance with
the microscope, I observed an abundance of well-preserved frustules of
Coscinodiscus, besides many other less conspicuous diatomes.

The fossil bones consist mainly of vertebrae and teeth of Cetaceans, the
teeth of Procamelus virginietisis, previously described, a portion of a humerus
of a bird, and a number of remains of fishes.

Among the latter there are two specimens which consist of portions of
the premaxillaries, with teeth, represented in Figs. 56, 57, Plate XXXII, of
a species of Tautoga larger than the living black-fish, Tautoga americana.

The better-preserved specimen exhibits the base of attachment of the
first large tooth, and succeeding it a row of seven teeth. These are separated
by wider intervals than the fewer teeth of the same kind of the recent black-
fish. The points of the teeth are more regularly conical tlian in the latter.
Within the position of the larger teeth there is a row of small teeth.

The second specimen contains the first large tooth alone. This tooth is
not longer than in the recent bl^ck-fish, but is more robust, and its enameloid-
covered extremity is more perfectly conical or is less flattened from without
inwardly.

The premaxillary bone is flatter externally than in the black-fish, and looks
as if it had not turned down in a hook-like end as in the latter. The speci-

347

mens I have supposed to indicate a genus closely related with Tautoga, and
have named it Protautoga.

The more complete specimen contained a row of eight teeth in a space of
an inch and a quarter from the symphysis. The first large tooth is 5J lines
long: the crown-like portion is 3J lines long, witli the breadth at base 2i
lines. The second tooth is 4.4 lines long; the crown-like portion is 2 lines
long and 1.6 lines in diameter at base. The other teeth range from 2 lines
to a line in length.

SPHYEiENID^.

ENCHODUS.

Enchodus Shumarui.

Leidy : Pr. Ac. ^^at. Sc. 1856, 257.
Described page 289, and represented by Fig. 20, Plate XVII. From the
Cretaceous of Sage Creek, Dakota.

PHASGANODUS.

Phasganodus oirus.

Leidy : Pr. Ac. Nat. Sc. 1857, 107.
Described, page 289, and represented by Figs. 23, 24, Plate XVII. From
the Cretaceous of Cannon Ball River, Dakota.

CLADOCYCLUS. ?

ClaDOCYCLUS 1 OCCIDENTALIS.

Leidy : Pr. Ac. Nat. Sc. 1856, 256.
Noticed page 288, and represented by Figs. 21, 22, Plate XVII, and Fig.
5, Plate XXX. From the Cretaceous of Sage Creek, Dakota.

Clupeid^.

CLUPEA.

ClUPEA HUMILIS.

Leidy : Pr. Ac. Nat. Sc. 1856, 256.
Page 195, and represented by Fig. 1, Plate XVII. From the Eocene
shales of Green River, Wyoming.

Clupea alta.

Described page 196, and represented by Fig. 2, Plate XVII. From the
Eocene shales of Green River, Wyoming.

348

CyPRINIDyE.

MYLOCYPRINUS.

Mylocyprinus robustus.

Leidy : Pr. Ac. Nat. Sc. 1870, 70.
Described page 262, and represented by Figs. 11 to 17, Plate XVII.
From the Pliocene of Idaho.

SlLURID^.

PIMELODUS.

PiMELODUS ANTIQUUS.

Leidy : Pr. Ac. Xat. Sc. 1873, 99.
Page 193, and represented by Figs. 44 to 46, Plate XXXII. From the
Tertiary of Big Sandy and Green Rivers, Wyoming.

FAMILY UNDETERMINED.

XiPIIACTINUS.
XiPHACTINUS AUDAX.

■ Leidy: Pr. Ac. Nat. Sc. 1870, 12.
Described page 290, and represented by Figs. 9, 10, Plate XVII. From
the Cretaceous of Smoky Hill River, Kansas, and L'eau qui Court
County, Nebraska.

GANOIDEI.

Cydoganoidei.

AMIA.

Amia uintaensis.

Amia fProtamiaJ uintaensis. Leidy : Pr. Ac. Nat. Sc. 1873, 98,
Page 185, and represented by Figs. 1 to 6, Plate XXXII. From the
Bridger Eocene of Wyoming.
Amia media.

Amia fProtamiaJ media. Leidy : Pr. Ac. Nat. Sc. 1873, 98.
Page 188, and represented by Figs. 7 to 11, Plate XXXII. From the
Bridger Eocene of Wyoming.

Amia gracilis.

Amia fProtamiaJ gracilis. Leidy : Pr. Ac. Nat. Sc. 1873, 98.
Page 188, and represented by Figs. 23, 24, Plate XXXII. From the
Bridger Eocene of Wyoming.

349

HYPAMIA.

Hypamia elegans.

Leidy : Pr. Ac. Nat. Sc. 1873, 98.
Page 189, aud represented by Figs. 19 to 22, Plate XXXII. From the
Bridger Eocene of Wyoming.

FAMILY UNDETERMINED.

PIIAREODUS.
Phaeeodus acutus.

Leidy : Pr. Ac. Nat. Sc. 1873, 99.
Page 193, and represented by Figs. 47 to 51, Plate 193. From the
Bridger Eocene of Wyoming.

Rliomhoganoidei.

LEPipOSTEUS.
Lepidosteus atrox.

Leidy': Pr. Ac. Nat. Sc. 1873, 97.
Page 189, and represented by Figs. 14, 15, Plate XXXII. From tlie
Bridger Eocene of Wyoming.

Lepidosteus ?

Leidy : Pr. Ac. Nat. Sc. 1873, 98.
Page 190, and represented by Figs. 16, 17, 25, 27 to 30, Plate XXXII.
From the Bridger Eocene of Wyoming.

Lepidosteus simplex.

Leidy : Pr. Ac. Nat. Sc. 1873, 98.
Page 191, and represented by Figs. 18, 26, 31 to 43, Plate XXXIL
From the Bridger Eocene of Wyoming.

Lepidosteus notabilis.

Leidy : Pr. Ac. Nat. Sc. 1873, 98.
Page 192, and represented by Figs. 12, 13, Plate XXXII. From the
Bridger Eocene of Wyoming.

PYCNODUS.

Pyc'nodus faba.

Leidy : Pr. Ac. Nat. Sc. 1872, 163.
Described page 292, and represented by Figs. 15, 16 Plate XIX. From
the Cretaceous of Mississip|)i and New Jersey.

350

Pycnodus robustus.

Leitly : Pr. Ac. Nat. Sc. 1857, 168.
Noticed page 293, and represented by Figs. 18, 19, Plate XXXVII. From
the Cretaceous of New Jersey.
Pycnodus cauolinensis.

Emmous: North Oaroliua Geol. Sur. 1858, 211, Fig. 96.
Noticed page 294. From the Miocene of North Carolina.

HADRODl^S.

Hadijodus priscus.

Leitly : Tr. Ac. Nat. Sc. 1857, 167.
Described page 294, and I'epresented by Figs. 17 to 20, Plate XIX. From
the Cretaceous of Mississippi. Specimen discovered by Dr. William
Spillman.
Since the determination of the reptilian character of the genus Placodus,
I have suspected that this one may also belong to the same order.

Placoganoidei.

ACIPENSER.

AciPENSER ORNATUS.

Leid y : Pr. Ac. Nat. Sc. 1873, 15 ; Am. Jour. Sc. 1873, 312.
Among the fossils in Mr. C. M. Smith's collection from the Miocene forma-
tion of Virginia, previously mentioned, there is a dermal plate of a stur-
geon, especially interesting on account of tlic rarity of the remains of
fishes of the same family.
The specimen is represented of the natural size in Fig. 58, Plate XXXII,
and is nearly entire. It appears to have been one of the lateral plates, and
indicates a species about the size of our common sturgeon of the Delaware
River. Though exhibiting no positive distinctive character, it most probably
pertained to a species now extinct.

ELASMOBRANCHI.

Holocepliali.

EDAPHODONTIDiE.

EDAPHODON.

Edaphodon mirificus.

Leidy : Pr. Ac. Nat. Sc. 1856, 221.
Described page 306, and represented by Figs. 6 to 12, Plate XXXVII.
From the Cretaceous of New Jersey.

351
EUMYLODUS.

EUMYLODUS LAQUEATUS.

Described page 309, and represented by Figs. 21, 22, Plate XIX, and Figs.
13, 14, Plate XXXVII. From the Cretaceous of Mississippi.

Plagiostomi.

Squalid^.

LAMNA.
Lamna ?

Described page 304, and represented by Figs. 44, 45, Plate XVIII. From
the Cretaceous of" Kansas and the Chalk of England.

Lamna \

Described page 304, and represented by Figs. 46 to 50, Plate XVIII.
From the Cretaceous of New Jersey, Mississippi, and Kansas.

OTODUS.
Otodus divaricatus.

Leidy : Pr. Ac. Nat. Sc. 1872, 1G2.

Described page 305, and represented l)y Figs. 26 to 28, Plate XVIII.
From the Cretaceous of Mississippi.

OXYRHINA.

OXYEHINA EXTENTA. - -

Leidy : Pr. Ac. Nat. Sc. 1872, 1G2.

Described page 302, and i-epresented by Figs. 21 to 25, Plate XVIII.
From the Cretaceous of Kansas and Mississippi.

GALEOCERDO.

Galeocerdo falcatus.

Described page 301, and represented by Figs. 29 to 43, Plate XVIII.
From the Cretaceous of Kansas, Mississippi, Texas, and England.

Hybodontid^.

CLADODUS.

Cladodus occidentalis.

Leidy : Pr. Ac. Nat. Sc. 1859, 3.

Cladodus mortifer. Newberry aud Wortben : Geo]. Sur. Illinois, vol. ii, Pake-

outology 22, Plate I, Fig. 5. St. Jobu: Haydeu's Rep. Geol. Sur. Nebraska,

1872, 239, Plate IH, Fig. 6; Plate VI, Fig. 13.

Described paifc 311, and represented .l)y Figs. 4 to 6, Plate XVII. From
the Carboniferous formation of Kansas, Nebraska, and Illinois.

CESTRACIONTIDiE.

ACRODUS.

ACKODUS HUMILIS.

Leidy : Pr. Ac. Nat. Sc. 1S72, 103.
Described page 300, and re|irescntc(l by Fig. 5, Plate XXXVII. From
the Cretaceous limestone of New Jersey.

AcEODUS Emmonsi.

Leidy : Pr. xVc. Nat. Sc. 1S72, 103.

Acroclus. Emmous: North Carolina Geol. Sur. 18.58, 211, Fig. 97.

Attributed by Professor Emmons to the Miocene of North Carolina.

PTYCHODUS.
Ptyohodus Mortoni.

Agas.siz: PoIssods Fossiles III, 1833-'43, 158, Tab. 25, Figs. 1 to 3; copied in
Figs. 773, 773rt, of Dana's Manual of Geology. Leidy : Pr. Ac. Nat. Sc. 1808,
205.

Palate-boiie of a fish ? Morton : Syn. Org. Rem. Cret. Group, 1831, Plate XVIII,
Figs. 1, 2.

Described page 295, and represented by Figs. 1 to 14, Plate XVIII
From the Cretaceous of Kansas, Mississippi, and Alabama.

Ptychodus occidentalis.

Leidy : Pr. Ac. Nat. Sc. 1868, 207.
Described page 298, and represented by Figs. 7, 8, Plate XVII, and Figs.
15 to 18, Plate XVIII. From the Cretaceous of Kansas.

Ptychodus Whippleyi.

Marcou : Geology North America, 1858, 33, Plate I, Fig. 4.
Described page 300, and represented by Figs. 19, 20, Plate XVIII.
From tlie Cretaceous of Texas.

Ptychodus polygykus.

Agassiz : Poissous Fossiles III, 1833-'43, 150. Dixon : Geol. Sussex, 1850, 363.
Gibbes: Jour. Ac. Nat. Sc. 1810, 290, Plate XLII, Figs. 5, 0. Leidy: Pr. Ac.

Nat. Sc. 1808, 208.

From the Cretaceous of Alabama.

PF/rALODUS.

PeTALODUS ALr.EGHANIENSlS.

Leidy: Jour. Ac. Nat. Sc. ISoG, 101, riato XVI, Figs. 4 to G; Pr. Ac. Nat. Sc.

1859, 3.
tVcariun cxtinvtus. Leidy: Pr. Ac. Nat. Sc. 1855, 411.
Petalodus destructor. Newberry and Wortbeii : tied. Stir, llliuois, vol. ii, I'al-

iBontology 35, Plate II, Figs. 1 to .'!. St. John : Haydeu's Eei). Geol. Sur.

Nebraska, 1872, 241, Plate III, Fig. 5.

Described page 312, and represented by Fig. 3, Plate, XVII. From the
Carboniferous formation of Kansas, Nebraska, Iowa, Illinois, and In-
diana.

Ichthyodorulites.

XYSTRACANTHUS.

Xystracanhus arcuatus.

Leidy : Pr. Ac. Nat. Sc. 1859, S.-
Page 312, and represented by Fig. 25, Plate XVII. From the Carbonif-
erous formation of Kansas.

'asteracanthus.

Asteracanthus siderius.

Leidy : Pr. Ac. Nat. Sc. 1870, 13.

Described page 313, and represented by Fig. 59, Plate XXXII. From
the sub-Carboniferous formation of Tennessee.

Rai.^:.

ONCOBATIS.

Oncobatis pentagonus.

Leidy : Pr. Ac. Nat. Sc. 1870, 70.
Page 264, and represented by Figs. 18, 19, Plate XVII. From the Plio-
cene of Sinker Creek, Idaho.

TRYGON.

Trygon .

Indicated Ijy the Ijasal portion of a caudal spine, represented in Figs. 54,

55, Plate XXXII. It resembles the corresponding ])ortion of the caudal

spines of our common whip-sting ray, Pastinaca hastata, and would appear

to have pertained to a species of about the same size. Tlie anterior, shining,

45 G

354

eiiaiueloid surface is strongly wrinkled longitudinally, and the lateral denticles
are directed downward.

From the Miocene formation of Virginia. Specimen discovered by Mr. C.
M. Smith in the blue clay beneath the city of Richmond.

MYLIOBATES.

Myliobates .

Indicated by the basal portion of a caudal spine, represented in Figs. 52,
53, Plate XXXII. In its relation of breadth to length, in comparison with
flic spines of ordinary rays, it would appear in the couiplete condition to
have been upward of 8 inches in length. The specimen, however, becomes
rather more abruptly narrowed at its upper broken extremity than appears in
ordinary spines, so that it may have been proportionately shorter than usual.

The transverse section has almost the Greek e form. In front the spine
is concave along the middle and convex at the sides ; behind it has the
reverse arrangement. The lateral denticles are directed downward and
backward. The anterior enameloid surface is strongly wrinkled along the
middle groove, but not so much at the sides, except at the 'base of the spine.
The posterior surface is moderately ridged.

Specimen fonnd with the preceding in the blue clay of the Miocene forma-
tion of Virijinia. From Mr. C. M. Smith.

INDEX.

[Synonyms aro in italic.']

Page.

Acanthopteri 288

Acipenser ornatus i 350

Acrodus 300,352

Emmonsi 301,352

Immilis 300, 352

Adociis I'liomingensis 341

AgriochoBrus antiquus 216, 319

latifrons 216,319

Amia 185,348

gracilis 188,348

media 188,348

uintaeusis 185,348

Anchippodus 328

riparius 72, 328

vetulns 329

Anchitlieridse 322

Aucliitlierinm 218, 250, 322, 323

agreste ...^,. 251,323

australe 250,323

Bairdi 218,252,322

Condoui 218

Anosteira oruata 174, 341

AutbracotlieridsB 320

Antrodanus 338

Apatoruis 266

Arclia'otlieyiiim 320

Artiodactyla 216,317

Asineops squamifrons 195

vii'idensis 195

Asteracauthus siderius 313,353

Atlantocbelys Mortoni 269, 342

tnberosus 342

Aucbenia 255, 317

californica 255

hesterna : 255,317

Ba€na 160,341

affinis 163,341

areuosa 161,341

uiidata 1()9, 341

Baptemys 154,341

wyomingensis 157, 341

Bison latifrons 253, 318

Buvidie 318

C. ,
C'anida; 315

C'anis indianensis 230,315

Pago.

Canis primwrus „ 315

vafer 315

CamelidiB 317

Carnivora 114,227,315

Cervidse 317

Cestraciontidfo 352

Cetacea 337

Cbameleo pristinus 184,345

Cbclouia 132,223,260,269,339

Cbisternon undatnm 169, 341

Chisternum .-.. 341

Cladocyclus occideutalis 288, 347

Cladodus occidentalis 311, 351

mortifir 312, 351

Clidastes 281,344

affinis 283,344

intermedins 281, 344

Clupea 195,347

alta .- 196,347

bnmilis 195,347

pusilla 195

Clnpeidse 347

Corax Iwterodon 301

Crocodilia 125

Crocodilns 125

aptns 126

Elliotti 123

Cycloganoidei 348

Cynocercus 343

incisus 269,343

Cypriuidai 262,348

DeliJbiuidte

Dicotyles

hesperins
liristinns.

Dinoceras

bxcnstris ..

bicaris

miraliilis ..

Dinosanria

337

216,319

217

216,319

232

334

.95,108,332,333
267,338

Edaiibodon mirilions.

Edapbodoutidiu

Elasmobraucbi

Elepbas

americanu.s. .

Cohimhi

306, 350
350
295, 350
238, 329
238, 329
238, 329

356

Page.

Klepbas imporator 329

Texanus 329

KlotbtTinm 124,217,320

iraperator 217,320

ingens 320

leutis 124

Mortoui 125, 320

supeibum 218

Emys 140,260

Carterl ' 137,339

Haydeni 140, 14&,310

Jeansi 140,143,340

petrolei 260,340

Stevensoniaiiiis 140,141,340

wyomiugeusis 140, 141, 340

Enchodus Shniiiardi 289, 347

Entdodon 320

Eobasileus 332,334

Equiila; 321

Equiis " 242,321

conqilicatiis 244, 321

excelsiis 243,322

major 244,321

occidentalis 242,322

pacificiis 322

parvuliis 252, 323

Ei'ismatopterus levatiis 195

Eickseckeri 195

Eitcrotaph us 212

Euelephas Cohmibi 330

Jacksoiii , 330

Eumjlodus laqueatiis 309, 351

Felida; 315

Felis aiigustus 227, 315

imperialis 228,315

Fisbes 184,261,288,346

Galeocei'do falcatus 301, 351

Gauoidei 292,348

Glyptosaurus 182, 345

ocellatiis 183

Grapbiodon viucariiis 337

Hadrodiis priscus 294, 350

Hadrobyus supremos 222, 321

Hippariou speciosum 247, 322

Hipposyus formosus 91, 321

robustior 93, 32 1

Uolcodus acutiiJens 342

corjipluviis 276, 34 4

Holocepbali 306, 350

Hybeniys arenariiis 174,340

Hybodoutidic 351

Hyopsiidiis 75, 320

niiunscuhis 81, 320

pauUis 75, 320

Page.

Hypaiuia elegaus J89, 349

Hyraebyus 59,327

agrarius (jO, 327

«grcstis 00, 327

eximius g6, 327

modestus 67,327

nanus 67,327

Icbtbyodorulitcs 353

Icbtbyoruis 266

lusectivora ■ 120 336

Labrid.T

Lacenilia 180,

Laniu a

cuspidata

elegans

Texana

Lefalofodon

Lepido.stens 189,

atrox

notabilis

simplex

Leptomcryx Evausi

Lestosanrus corypbajus

lAmnoliyus

Icevidens

latieeps

rohustus

Limnolhmum elegans

Limnotlierium tyraimus

lAodon dyspelor

proriger

Lophiodon

Bairdiaiius

modcstus

nanus

occidentalis

parisiense

Lopbiotherium . . ;

Ballardl

sylvaticnni

Loxoloplwdon

Lutra .

l>iscinaria .

346
, 285, 344
303, 351
305
305
305
332
, 190, 349
189, 349
192, 349
191,349
216,317
276, 344
57, 323
323, 325
326
326
84, 320
83,89
271,343
344
219, 327
60, 327
67, 327
68, 327
220, 327
98
69, 327
71
.09,327
332, 333
230, 316
316

JI.

Macrosaurus proriger 340

Jlabicopteri 294

Mammalia :... 27, 199,211,227, 315

Manatus iuornatus 336

Mastodon 231,330

amcricaniis 237, 330

anccps 94, 334

mirificii.s 237, 330

(ib.scunis 231,330

Shcpardi 2.35, 330

3.07

Pago

Megacerops 2a9, 335

coloradensis 239, 335

Mcgaceratops coloradoeiisis 335

Megalomenyx 2G0

niobrarensts 260, 317

Mery cbippus 248, 322

mirabilis 250, 322

Muiycbyus 202

elegaus 201

major 201

medius 201

Merycodus uecatiis 318

Meryeochttius 199, 202, 208, 319

proprius 201

rusticns 199, 319

Miacis 310

Microsus cuspidatiis 81, 322

Mierosyops 82, 320

elegaus 8-1, 320

gracilis 83, 320

Mosasauria 270, 343

Mosasaurus 279, 343

Mitchein 342

Murida?. , 336

Mustelid* 310

Myliobates 353

My locyprinus robiistus 262, 348

Mysops Ill, 336

frateruus 112, 336

minimus Ill, 330

N. .

Notluirclus rohusliof 93, 321

Notbarctus teuebrosus 86, 329

Kolhijsaiin)2>s occidmis 287,345

Notbosaiirus occiduus 287, 345

Omni vora 319

Omomys Carter! 120, 336

Oucobatis pentagouus 264, 353

Oligosimus graudaivns.. 286,345

Oreodontidse . , 318

Oreodon 201,211,318

affinis 212

bullatus 212,318

Cnlbertsoiii 211,318

gracilis 211

bybridiis 212

major 211

occidentalis 3] 8

snperbu/* 211,319

Osteoglossum encaustum 195

Otodus divaricatns 305, 351

Oxyrbiua 302, 303, 351

extenta 302, 351

Palajacodoii 122, 336

venis 122, 336

raso.

Pal;cosyops 27,323

biimilis 58,326

Junius 57, 326

jiiiiioy 326

laliapf! 325,326

major 45,326

minor 72, 328

paludosus 28, 325

Palaucbeuia magna 255

Paramys 109, 335

delicatior 110,335

delicatissimus Ill, 335

delicatus 110, 335

Patriofelis ulta 114, 316

Perissodactyla 27,219,321

Petalodus allegbanieusis 312, 353

destructor 313, 353

Pbareodus acutus 193, 349

Pbasgauodus dirus 289, 347

Pimelodus antiquus i 193, 348

Placoganoidei 350

Plagiostomi 295,311,351

Platecarjms 342, 344

tuherosiis 342, 344

tympaniticus 342

Platygonus Coudoni 217

Poicilopleuron Buclilaudi 268

valeus 267,338

Polycotylus latipinnis 279

Pontobasileus tuberculatus 337

Proboscidea 93, 231, 329

Procamelus occidentalis 258, 317

niobrarensis 317

robustus 258, 317

yirginiensis 259,317

Protamia 185,348

Protautoga conidens 346

Protocamehis ..'. 317

Protobippus 248,322

perditus 249,250,322

idaeidus 248,322

Protostega gigas 269

inptiiiiia 342

tiilnro!ia 269, 342

Ptycbodus Morton i 295,352

occidentalis 298,352

polygyrus 352

Wliipployi 300,352

Pycnodus 292,349

carolincnsis 294,350

faba 292,349

robustus 293,350

It.

Eal:r 264,353

Reptilia 125,338

Kcptilcs 267

lihaniphosauriis 271,343,344

Rbinoceros 220,328

anncctaus 328

358

Ehiuoceros hesi>eii us

occidciitalis

oregoueuiiis

jjaciflcus

Uhinosaurns

d!/8j)elor

proriger

Ehomboganoidei

Ebyucbothei'inm

Rodenti.a

Enminantia - 199, 2U,

Saniva

Saniwa ensideus

major

Sauropterygia ■

Sciuravus

nitidus

undans

Scinridie

Sicarius exiinctus

SiluridoB -

Sinopa

eximia

rapas

Sirenia

Soliduugiila 208,218;

SpliargididjB

Sphy rsBuidio

SqualidiB

Styleniys

Culbertso7ii

otrgonensis

nchrascensis

niohrarfiisis

Page.

2ii0, 328

328

221, 328

271

343

344

349

237, 330

109, 335

953,317

Suidse

181, 344

181,344

181, 345

286, 345

113, 335

113

335

353

290, 348

11(3,316

118,316

116,316

336

242, 321

342

288, 347

351

223

339

226, 340

224. 339

225. 340
319

Page.

Testudo Culberlsoiii 339

hemisjjherica 339

lala 339

nebrasceusis 339

niobrareusis 340

oregouensis 340

Tetralophodon mirifictis 330

Tylosaunis dyspelor 271, 343

jiroriger 274, 344

Tylosteiis ornatus 285, 345

Tinociras 331

aneeps 94, 334

grandis 94,334

Titaiiolhei'inm aneeps 94, 334

Triacodou falax 123

Triouyebidaj 341

Trioujx 176, 180, 341

guttatus 176, 341

iiintacusis 178,342

Trogosus castoridens 71, 32S

vclulus 75, 329

Tiygon 353

Uintacyou edax 118, 310

vorax 120,316

Uintamastix 331

atrox 94, 107, 333

Uintatherium 93,331

aucep.s 334

nuruhile . 333

robustiim 93,96,333

Tautoga 346

Teleostel 288,346

Tdmatheiium 323

Testudinida* 339

Testudo Corsoni 132, 339

Vnlpavus palustris

118

Wasbakius iusignis ._ 123, 336

Xiphactiiius audax 290,348

Xystracautbus arcuatns 312, 353

Zeuglodontia . 337

EXPLANATION OF PLATE I.

Fig. 1. Oreodon supeebus:

A side view of a skull, witli the base of tbe cranium iuvested in tlie matrix. Specimen ob-
tained by Rev. Thomas Condon on John Day's River, Oregon. One-half the natural size.

Figs. 2,3. MEGACfiROPS COI.ORADENSIS :

Fig. 2. Upper view of the nasal extremity of the face with a pair of horn-cores. Oue-half

the natural size.
Fig. 3. Front view of the same specimen

U. S. Geological SuTvay of the Temtoneo.

Plate I

T SINCLAIR ft SON. PHILADELPHIA.

OR,EODON SUPERBUS. %

2 % MEGACEROPS COLOR/ DENSI3 '^

EXPLANATION OF PLATE II.

Fig. 1. LOPHIODON OREGOXENSIS :

Two upper molar teeth, much worn and seen on theii- triturating surfaces. Specimen from
Bridge Creek, Oregon. Natural size.

Fig. 2. Megacekops coloradensis :

Side view of the same specimen as that of figures 2, 3, of Plato I. One-half the natural size.

Figs. 3, 4. Elotherium superhuji :

Fig. 3. Portion of a lower canine tooth, natural size. From Bridge Creek, Oregon.
Fig . 4. Crown of an anterior premolar, natural size. From John Day's River, Oregon.

Fig. 5. A^■c•HrrIIERIUM Condoni :

A mutilated upper molar tooth, natural size. From Oregon.

Figs. 6,7. Rhinoceros pacificus:

Fig. 6. An upper molar seen on the triturating surface, natural size. From Alkali Flats,

Oregon.
Fig. 7. An upper last premolar, seen on the triturating surface, natural size. From Alkali

Flats, Oregon.

Figs. 8,9. Rhinoceros hesperius(?) :

Fig. 8. An upper last molar, seen on the triturating surface, natural size. From the Condon

collection of Oregon.
Fig. 9. An inferior molar, seen on the triturating surface.

Fig. 10. Patriofelis ulta:

Portion of the right ramus of the lower jaw, half the natural size. It contains the remains
of five teeth behind the position of the canine. From near Fort BriJger, Wyoming. See
page 114.

Figs. 11, 12. Hyrachyus agrarius :

Fig. 11. Left ramus of the lower jaw, one-half the natural size. Specimen obtained by
Professor Hayden on Smith's Fork of Green River, Wyoming.

Fig. 12. Portion of the left ramus of the lower jaw of a young animal, natur.il size. It con-
tains the temporary series of teeth behind which the first of the true molars is inclosed
within the jaw. From Black's Fork of Green River. Hayden's collection.

Fig. 13. Hyrachyus modestus :

A first or second upper molar of the left side, slightly larger than natural. From Smith's
Fork of Green River. Hayden's collection.

Fig. 14. Hyraohy'US nanus :

Portion of left ramus of the lower jaw, with two premolars and the three molars, natural
size. Obtained by Dr. Joseph K. Corson from Grizzly Buttes.

Fig. 15. Diseased calcaneura (hyperostosis) of Merycochcerus uusticus. From Sweetwater River.
Hayden's collection of 1H70.

Fig. IG. Oreodon superbus :

Portion of right ramus of lower jaw, with the three premolars and first molar; natural size.
Condon collection of Oregon fossils.

D b G.eological Survey of the TerntorieB

Plate ri

*fci»^ "; ,'Sa»=

\-\

p^#

^*^^^«-4,.^4^

;^.

T- StNCW/'H A SON ^■■^lLA^:>ELPMIA

1 LOPHIODCN.

2 MEGACEROPo. -^

S. 4 ELOTHERIUM. 1 6-9 RtllNOCEROS
S ANCHr)'Hl;;RirMj 10. PATRIOFELLi
16 OREODON.

il-hi HfRACHY'ie

i& iVlERYCOCaCERaS

EXPLANATION OF PLATE III.

Figs. 1-3. Merycochcerus rusticus. Figures of the natural size. Specimeus from Sweetwater River,
Wyoming. Hayden's collection of 1870.

Fig. 1. Upper jaw, with a nearly complete series of teeth, the last molar introduced from
another specimen.

Fig. 2. Front view of the same specimen, exhibiting the high alveolar border and the nar-
row nasal orifice.

Fig. 3. Lower jaw, witli a full series of molar teeth.

Fig. 4-6. Testudo or Stylbmvs niobrarensis. Figures of the natural size, except Figure 6, which is
one-half the size of nature. From the Niobrara River. Ilaydeu's collection of 1857.
Fig. 4. Internal view of the fore-part of the plastron.
Fig. .5. The last vertebral and the pygal plates.

Fig. 6. Internal view of a posterior portion of the carapace, exhibiting the costal capitula,
and the processes for conjunction with the pelvic girdle.

U. S. Geological Sur-vey oC the Terntonec

Plato III.

. SINOLAIB * BON. PMlUAOtCPHIA

]-S MERYCOCHOERUS RUSTICU3. | 4-6. STYL£.M^S NIOBRARENSIS.

EXPLANATION OF PLATE IV.

Figures all of the natural size. Specimens all from the Bridger tertiary formatiou of
Wyoming.

Figs. 1-8. Pal/EOsyops paludosus:

Fig. 1. A mutilated upper canine of the supposed female, from the same individual as the

specimens of figures 5-8.
Fig. 2. Mutilated canine of the supposed male, from the specimen of the following.
Fig. 3. A complete series of molar teeth aud the mutilated canine of the left side of a fine

specimen discovered at Grizzly Buttes by Dr. J. Van A. Carter. View of the triturating

surfaces, partially worn, of the molar teeth ; from a supposed male.
Fig. 4. Outer view of the crowns of the same molar series.
Fig. 5. A complete series of molar teeth, discovered by Dr. Carter ou Henry's Fork of Green

Kiver. View of the triturating surfaces; more worn than in the preceding specimen.

From a supposed female. .

Fig. G. Quter view of the anterior two premolars of the same specimen.
Fig. 7. A third upper premolar, left side. Specimen from Henry's Fork. Hayden's coUec-

tiou of 1870.
Fig. 8. Lateral view of an upper incisor. Specimen probably from the same individual as

that of Fig. 5.

Figs. 0-18. Hyrachyus agrarius :

Fig. 9. Outer view of the crowns of an upper series of molar teeth.

Fig. 10. View of the triturating surfaces of the same teeth. From a specimen discovered by

Dr. Carter near the Lodge-pole trail, eleven miles from Fort Bridger. All the teeth con-

.siderably worn.
Fig. 11. An upper second true molar, left side. Found by Dr. Carter on Henry's Fork of

Green River.
Fig. 12. An upper last premolar, left side, but little worn. Specimen found by Dr. Joseph

K. Corson at Grizzly Buttes.
Fig. 13. A iJortion of the lower jaw; from the same individual as Figs. 9, 10. It contains

part of the lateral incisor, the canine, and the premolars.
Fig. 14. View of the triturating surfaces of the premolars, from the same specimen.
Fig. 15. Outer view of a second lower molar, from the same individual.
Fig. 16. Triturating surface of the same specimen.
Fig. 17. An upper canine, found at Grizzly Buttes by Dr. Corson.
Fig. 18. A lower iucisoi, from the same individual as Fig. 13.

Figs. 19, 20. Hyeaciiyus exijiius. Specimen found by Dr. Carter on Henry's Fork of Green River.

Fig. 19. Fragment of the left side of the lower jaw, containing the last premolar and tho

greater part of the tirst molar.
Fig. 20. View of tho triturating surfaces, much worn, of the same teeth.

U. S, Geological Survey of the Terntoriee.

T^ SINCLAIR * SON, PHILAOCLPMIA

1-8 PALAEOSYOPS PALLTDOSUS | 9-18. HYRACHYUS AGRARIUS.

ly au. HYRACHYUS EXilvUaS.

EXPLANATION OF PLATE V.

All the figures of the natural size except Fig. 11, -which is one-half the size.

rigs. 1-3 Trogosu.s castoridens. A lower jaw, discovered iu the vicinity of Fort Bridger by Dr.

Carter.
Fig. 1. View of the left ramus of the jaw.
Fig. 2. Triturating surface of the second true molar, much worn. The other molars are too

much injured to ho characteristic.
Fig. 3. Front view of the jaw, exhibiting the large rodent-like incisors.

Figs. 4-11. Pal^osyops paludosus :

Fig. 4. An upper last premolar, the triturating surface much worn. From Henry's Fork.
Hayden's collection.

Fig. 5. An upper last premolar, nearly unworn. This is one of the original specimens upon
■which the genus and species were established. From Church Buttes. Hayden's collec-
tion of 1870.

Fig. 6. Outer view of a last upxier molar, left side. Henry's Fork. Hayden's collection
of 1870.

Fig. 7. Triturating surface of the same specimen ; the outer fore-part much fissured, with
the i)ortions displaced and the single inner lobe partially broken away.

Fig. 8. Outer view of a second njiper molar, from the opj)Osite side of the same individual.

Fig. 9. The triturating surface, with the outer lobqs much worn. Figs. 6-9 are from
specimens, which were attributed to the same species at the time of the original uotice of
it in the Proceedings of the Academy of National Sciences, Philadelphia, 1870, p. 113.

Fig. 10. View of the triturating surfaces of the last two premolars and the molars from the
specimen represented in the next figure.

Fig. 11. Left ramus of a lower jaw, containing the teeth just indicated. This fine specimen
was discovered by Dr. Carter thirteen miles southeast of Fort Bridger.

U. H Geological Survey of the Territoriee.

Plate V.

T. SINCLAIR d> SON, PHILADELPHIA

1-S TROGOSUS GASTORIDENS,

4-11. PALAEOSYOPS PALUDOSUS.

EXPLANATION OF PLATE VI.

Figs. 1-9. Hyopsodus paulus. All of the natural size except Figs. 2, 5, 8, 9, which are niagnified four

diamoters.
Fig. 1. Right side of lower jaw, with the three molars. From au individual past maturity.

Specimen from which the genus and species were firsfeuoticod.
Fig. 2. Triturating surfaces of the molars of the same specimen.
Fig. 3. Left side of lower jaw, with last premolar and the three molars. Specimen obtained

by Dr. Corson at Grizzly Buttes.
Fig. 4. Eight side of lower jaw, with last premolar and the molars, but slightly worn.

Specimen obtained by Dr. Carter.
Fig. 5. Triturating surfaces of the teeth from the same.

Figs. 6, 7. Left side of two lower jaws containing the molars. From mature but compara-
tively young individuals. Dr. Carter.
Fig. 8. Series of the back two premolars and the molars of the right side. From a specinleu

loaned by Dr. Carter.
Fig. 9. First and second lower molars of the right side. From another specimen loaned by

Dr. Carter.

Figs. 10, 11. MicROsns cuspidatus :

Fig. 10. Portion of left side of lower jaw, with back two molars, natural size. Specimen

from Black's Fork of Green -River.
Fig. 11. Triturating surfaces of the two molars, magnified four diameters.
Fig. 12. Portion of right side of lowcfi- jaw, probably pertainiug to the last-named animal.

It coutaius the roots of the molars and the last premolar, the triturating surface of which

is represented in Fig. 13, magnified four diameters. Specimen obtained by Dr. Carter near

Fort Bridger.

Figs. 14-17. MiCRO.SYOPS gracilis:

Fig. 14. Left side of lower jaw with the molars, natural size. Fig. 15. Triturating surfaces

of the molars, magnified four diameters. Specimen obtained at Grizzly Buttes by Dr.

Carter.
Fig. 16. Left side of lower jaw, with the second molar and portions of the others, natural

size. Fig. 17. The triturating surface of the second molar magnified four diameters.

Specimeu obtained by Dr. Carter at Grizzly Buttes.

Figs. 18-22. Hyopsodus padlus:

Fi"-. 18. Right upper jaw, with three premolars and the molars, magnified 'two diameters.

Fig. 19. Tritiu-atiug surfaces of the teeth magnified four diameters. Specimen obtained
by Dr. Carter at Grizzly Buttes, aud apparently pertaining to the same individual as that
of Fig. 14.

Fig. 20. Triturating surfaces of the right upper molars, magnified four diameters, from a
second specimen. Dr. Carter.

Fig. 21. Triturating surfaces of back two premolars and first molar of the left side, magni-
fied four diameters. Obtained by Dr. Carter at Lodge-polo trail.

Fi"'. Hi. Triturating surfaces of upper secoud and third premolars of right side, magnified
four diamoters. Dr. Carter.

Figs. 23-25. PARAMY.S del!Catu.s :

Fig. 23. Right side of lower jaw, with all the molars, natural size. Fig. 24. Triturating
surfaces of the molars except the last, which is broken away csccptiug the outer portion,
magnified three diameters. Grizzly Buttes. Dr. Carter.
Fi". 2.'>. Triturating surfaces of the molar series, except the last, of the lower right side,
magnified three diameters. From another specimen loaned by Dr. Carter.

PLATE VI.

Figs. 26, 27. Paramys uelicatiok :

Fig. 26. Left side lower jaw, with the second molar, natural size. Grizzly Buttes. Dr.
Carter. Fig. 27. Triturating surface of the second molar, magnified three diameters.

Figs. 28, 29. Paramys delicatissimus :

Fig. 28. Eight side of lower jaw, with all the molars, natural size. Grizzly Buttes Dr.
Carter. Fig. 29. Triturating surfaces of the molar series, magnified three diameters.

Fig. 30. ScitjRAVUS(?) Triturating surface of a lower left third molar, magnified eight diameters. From
a portion of the lower jaw obtained at Grizzly Buttes hy Dr. Carter.

Figs. 31,32. My'.sops minimus:

Fig. 31. Right side of lower jaw, with third and fourth molars, magnified two diameters.
Fig. 32. Triturating surfaces of the teeth, magnified eight diameters. Dr. Carter.

Figs. 33-35. LOPHIOTHERIUM SY'LVATICUM :

Fig. 33. Portion of left side of lower jaw, with last premolar and first and last molars,
natural size. Fig. 34. Triturating surfaces of the last premolar and first molar. Fig. 35.
Triturating surface of the last molar. Specimen from Henry's Fork of Green River.

Figs. 36, 37. NOTHARCTUS TENEBROSUS :

Fig. 36. Eight side of lower jaw, with canine and all the molar series except the first pre-
molar, natural size. Fig. 37. The triturating surfaces of the molars, magnified two
• diameters. Specimen from Black's Fork of Green Elver.

Figs. 38, 39. HipposTus roMosus (?)

Fig. 38. Triturating surface of a lower right second molar, magnified two diameters. From

a jaw-fragment from near Fort Bridger. Dr. Carter.
Fig. 39. Trituratiug surface of a left lower first molar, magnified two diameters. From a
jaw-fragment obtained by Dr. Carter near Fort Bridger.

Fig. 40. HiPPOSYUS ROBUSTIOR :

Triturating surface of a left lower second molar, magnified two diameters. From Henry's
Fork of Green Elver. Professor Haydeo.

Fig. 41. HiPPOSYUS FORMOsus :

Triturating surfaces of the upper left first and second molars, magnified three diameters
Specimen firom near Fort Bridger. Dr. Carter.

Fig. 48. Hyrachyus nanus.:

Triturating surfaces of the back two premolars, and the molars, magnified one and a half
diameters. Taken from the left side of the lower jaw of the same sjiecimeu represented
in Fig. 14, of Plate II. Specimen obtained by Dr. Corson at Grizzly Buttes.

Fig. 43. Trogosus vetulus, probably Anchippodus :

Eight lower incisor, natural size. From near Fort Bridger. Dr. Carter.

Fig. 44. SiNOP.t^ RAPAX:

Portion of left side of lower jaw, with last premolar and first molar, natural size. From
Grizzly Buttes. Dr. Carter.

Fig. 45. SiNOPA ExiMiA :

Portion of left side of the lower jaw, supposed to belong to a smaller species of the former
natural size. From Grizzly Buttes. Dr. Carter.

Fig. 46. Pal^acodon verus :

Penultimate molar of the upper left side, maguitied four diameters. From Lodge-polo trail.
Dr. Carter.

ij S. Geological Kurvey oi' the Territories.

Plate VI

pec%iii\

J' tv

1-9. HYOPSODUS PAULUS.
10, 11. MICROSUS CUSPIDATUS
12, 13.

14-17. MICROSYOPS GRACILIS
18-22.

23-26. PARAMTS DELICATDS.
26, 27 P DELICATIOR.

28, 29 P DELICATISSIMUS.

30.

31, 32. MTSOPS MINIMUS.

33-36. LOPHIOTHERItJM STLVATICUM.

36, 37. NOTHARCTUS TENEBROSUS.

38, 39,

40,

T SINCLAIR a SON LITH PHILAD*

41.

42. HYRACHYUS NANUS.

43 ANCHIPPODUS VETULUR

44, SINOPA RAPAX.

48. ,

46. PALvEACODON VERIS

EXI^LANATION OF PLATE VII.

All tbo figiu'cs are of tbo natural size, except Fig. 10, wliicb is retluced to oue-balf the diaui-
eter of the original.

Figs. 1-5. Merycocbcerus rusticus. From specimens obtained on Sweetwater River, Wyoming, by
Professor Haydeu's party in 1870.

Fig. 1. Series of upper molars of tbc right side, viewed on their tritnrating surfaces. The
last tooth bad not entirely protruded, and m the lirst ono the median enamel-pits are
nearly obliterated.

Fig. 2. Upper last premolar and molar of the left side, of the temporary series.

Fig. 3. Upper second and third premolars of the left side, of the permanent scries. The trit-
urating surfaces but slightly -worn.

Pig. 4. Outer view of the same teeth, in a small jaw-fragraeut.

Fig. 5. Symphysis of the lower jaw, with the four incisors on each .side.

Fig. fi. Mekycochceiuis pkoprics. First and second upper molars of the right side. From a specimen
obtained on the Niobrara River, by Professor Hayden, in 1857.

Figs. 7-11. Oreodon supercus. From specimei^s discovered in Oregon by the Rev. Thomas Condon.
Fig. 7. Last lower molar of the right side, viewed on the triturating surfixco.
Fig. 8. First and part of the second molars, from the same jaw-fragment as the preceding

figure.
Fig. 9. The three lower jjremolars of the right side, viewed ou their triturating surfaces.

From the same specimen as Fig. 16, Plato II.
Fig. 10. Upper view of the intermediate portion of the face, one-half the natural size.
Fig. 11. View of the inner surface of a lower canine, from the left side of a specimen of a

jaw, which lies with its outer face imbedded in a hard mass of rock.

Fig. 12. Oreodon Culbertsoni. A series of upper true molars of the left side. Specimen discovered

by Mr. Condon on John Day's River, Oregon.
Figs. 13, 14. DicoTYi-ES PRI.STIN0S. Specimens in the Condon collection of Oregon fossils.

Fig. 13. Triturating surface of a lower penultimate molar.

Fig. 14. Outer view and view of the triturating surface of a lower last molar. _
Fig. 15. Anchithekium Bairdi. An upper right molar. From the Condon collection.

Figs. 16, 17. ANcniTHERiUM agreste. From a specimen found ou Red Rock Creek, one of the head
streams of the Jefferson Fork of the Missouri. Obtained by Professor Hayden in 1871.

Fig. 16. Lower last premolar and first molar of the left side. Triturating surface much
worn.

Fig. 17. Last molar, from the same specimen of the jaw as the former.

Figs. 18, 19. Felis ACGUSTU.S. Specimens discovered by Professor Hayden on the Loup Fork of the
Niobrara River, Nebraska.
Fig. 18. Portion of the right premaxillary, containing the second incisor, viewed in front.
Fig. 19. Upper sectorial molar of the left side, viewed externally.

Fig. 20. Patriofells ulta (?) A premolar, probably of the up^ier jaw. Specimen found by Dr. Carter in
the vicinity of Fort Bridger, Wyoming.

Figs. 21-23. Teeth of a carnivore, undetermiued. Obtained by Professor Haydeu's party on Henry's
Fork of Green River, Wyoming.
I<'')g. 21. Outer view of the crown of an anterior premolar. Fig. 22. tljiper view of the same.
Fig. 23. Outer view of the crown of a eauiue tootli.

PLATE VII.

Figs. 24, 25. Rhinoceros pacikicus. A left iuferior molar tooth, from Bridger Creek, Oregon, belonging
to the Coiulou collection.

Fig. 24. View of the outer part of the crown. Fig. 25. Triturating surface of the same speci-
men.

Fig. 26. A canine tooth of au undetermined animal, probably of a large carnivore, but it may
be of an Elotherium-like pachyderm. The specimen belongs to the Condon collection of
Oregon fossils, and is labeled '■ Alkali Flats."

Fig. 27. Elotherium ihperatok. a supposed incisor tooth, inner view. Specimen labeled " Bridge
Creek," and belonging to the Condon collection of Cregor fossils.

Figs. 28, 29. Elotherium Mortoni? An incisor tooth, obtained by Mr. Peiroe, of Denver, twenty miles
southeast from Cheyenne City, Wyoming.
Fig. 2H. Inner view of the tooth. Fig. 29. Outer view of the same.

Fig. 30. Canine of an undetermined carnivore. It resembles the iuferior canines of a bear^
but is more comi^ressed. Specimen discovered by Professor Haydeu on White River, Da-
kota, in 1866. The crown is compressed conical, with the inner surface defiued in the
usual manner by acute borders. The faug exhibits a gibbous character. Length of crown
11 lines ; breaflth at base, 8 lines ; thickness, H lines.

a. S. Geological Survey of the Tarntoriea.

Plate VII.

iSmClMtiSOHUTH PHtU

EXPLANATION OF PLATE VIII.

Figures all oue-half the diameter of uature.

Fig. 1. A lumbar vertebra of a crocodile. From Little Sandy River. Haydeu's collection of
1870. (Crocodilus Elliotti.)

Fig. 2. Crocodilus .vptus :

A cervical vertebra, found on South Bitter Creek, Wyoming.

Fig. 3. A first caudal vertebra of a crocodile. From Little Sandy River. Hayden's collec-
tion of 1870.

Figs. 4-6. Crocodilus Elliotti. Hayden's collection of 1870.

Fig. 4. Portion of tbo left maxillary, containing tUe fourth and fifth teeth of that bone

From the junction of Big Sandy and Green Rivers.
Fig. 5. Upper extremity of a left femur. From near Little Sandy River.
Figs. 6, 7. Upper view of a large portion of the skull. Found by H. W. Elliott, ou Little
Sandy River.
. Fig. 8. Left ramus of the lower jaw of a larger individual, or jierhaps of a larger species.
Discovered in the vicinity of Fort Bridger by Dr. Josei)h K. Corson, and presented by him
to the Academy of Natural Sciences of Philadelphia.

U. S. Gfoloc^icai Sui-v'»T .;i in-r T^rnioT.e

Plate VIII

"^-c^

^ - V

■ f^ ±d'' »«.' vW

I. SINCLAIB a SON. PulLAOELFm*

CROCODILES. H SIZE

EXPLANATION OF PLATE IX.

All the figures lialf the natural size.

Fig. I. Trionyx guttatus :

Portion of a carapace, consisting of the third to the sixth vertebral iilates, inclusively,
together with parts of the contignous costal plates. Specimen obtained at Church Buttes
during Professor Hayden's exploration of 1868.

Figs. 2-6. Emys wyomingensis :

Fig. 2. Portion of a carapace comprising the vertebral jjlates from the first to the eighth
inclusively, together with small portions of some of the contiguous costal jilates.
Specimen, originally referred to Emijs Sterensoniamis, obtained l)y Dr. Carter in the
vicinit.'^of Fort Bridger, and presented by him to the. Smithsonian Institution.

Fig. 3. Portion of a plastron, ivhich accompanied the jireceding specimen and was origi-
nally referred to E. Slcrcnsoiiianus.

Fig. 4. Anterior fragment of another plastron, accompanying the former two specimens, and
likewise referred to E. Steveiisoriiaiuis.

Fig. 5. An episternal, upon which the species Emys wijomiiif/ensiii was first noticed. Specimen
found by Dr. Carter near Fort Bridger.

Fig. 6. Central portion of a carapace, originally attributed to Emys Saydeiii. Specimen
obtained near Fort Bridger. Haj'den's collection.

Fig. 7 Emys petrolei:

Two episternals from different individuals. Specimens from Hardin County, Texas.

D
H

EXPLANATION OF PLATE X.

Represents the nearly complete shell of Eai YS wyomingensis, one-lialf the natural size. It was originally
referred to a species with the name of Emys Jeaneni. Specimen obtained from the vicinity
of Fort Bridger, dnring Professor Hayden's exploration of 1870.

Fig. 1. View of the plastron.

Fig. 2. View of the carapace.

EXPLANATION OF PLATE XI.

Testudo Oorsoni :

Both specimens iieitainetl to the same shell, aurt were originaUy described uuder the name

of Eiiii/^ Carteri. They were discovered near Fort Bvldger by Dr. Carter, and presented to

the Academy of Philadelphia.
Fig. 1. The greater part of the iilastron, its anterior extremity to the right, one-third the

natural size.
Fig. 2. The anterior intermediate portion of the carapace, its front to the left, one-half the

natural size.

U. S, Geological Survey o? the Terntonea

Plate XI,

T, SINCLAIR l> SOM. OMiLAOELPHIA,

EXPLANATION OF PLATE XII.

Baptemys wyomxngensis :

Figures one-third the natural size. Specimen discovered at Church Buttes, Wyoming, by
Mr. O. C. Smith, of Leverett, Massachusetts, while engaged in service of the Union Pacific
Eailroad. It now belongs to the museum of the Academy of Natural Sciences of Phila-
delphia.

Fig. 1. View of the carapace.

Fig. 2. View of the sternum.

m
o

EXPLANATION OF PLATE XIII.

BaSna akenosa :

Figures one-half the natural size.

Figs. 1, 2. Specimen on which the genus and species were originally estahlished. Dis-
covered at the junction of the Big Sandy and Greeu Rivers, Wyomiug, during Profe.ssor
Hayden's exploration of 1870.

Fig. 1. View of the carapace.

Fig. 2. View of the plastron, its anterior extremity lost.

Fig. 3. View of the plastrou of another specimen, originally referred to a species with the
name of Baina affinis. It was discovered by Dr. Carter at Chnrch Buttes, and was pre-
sented by him to the Academy of Natural Sciences of Philadeljihia.

^- *F?r^r5>'

. ^«if^

tfff^^p^

.-■■^'t

.r^-^iSJ,"

-gSsj^feii-j -;..'■ "®^'%^'

<,»a5'Sf'^.|

i^-*ij

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jSjisw^-.'^a »- ■^'^Set^i^^JiT^*-

^ji»^7%"* *cV^ *--i^^ T ^ "* •<'~ j( t ^«^^

n"~^-'^.

,-#!*-

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EXPLANATION OF PLATE XIV.

Chisternon dndatum, originally referred to Bai^ita niiilata. Figures oue-balf the natural size. Speci-
men discovered in the vicinity of Fort Bridger by Dr. Carter, and presented by him to the
Academy of Natural Sciences.

Fig. 1. View of the carapace ; the sutures scarcely visible.

Fig. 2. View of the greater portion of the plastron, with the left border of the carapace.
The crucial suture of the plastron is visible, from which the genus received its name.

'?'

i^'ls'f-SSi,.^

>^-—'-:~-~

■>>-

\ ■
-1'

:igi^y*^'

EXPLANA'J'ION OF PLATE XV.

Figs. 1-5. Ba^ na arenosa :

Fig. 1. Anterior extremity of the i)lastron,'eshil)itiiig the two pairs of gular scute areas.

From the same specimen as Fig. 3, of Plate XIII. One-half the natural size.
Fig. 2. Anterior extremity of the plastron, from another specimen found by Dr. Carter on

Henry's Fork of Green River. Tlie gular scute areas are larger, and the surface of the

plates is conipurafively smooth. One-half the natural size.
Fi"'. 3. From a specimen fonud by Dr. Corson at Grizzly Buttes. It is of greater proportiou-

ate breadth than the former, and presents x want of symmetry in the gular scute areas.

One-half the natural size.
Figs. 4, 5. Of the natural size. From a young specimen obtained by Professor Haydeu's

party "at the junction of Big Sandy ^nd Green Rivers. It retains the sutures, which are

obliterated in the preceding mature specimens.
Fig. 4. Inferior view.
Fig. 5. Superior view, exhibiting the trident form of th3 eutosternal bone.

Fi"-. 6. Baptemvs wyomingensis. One-half the natural size. A portion of the anterior extremity of
the plastron, from a specimen obtained by Professor Haydeu's party at Church Buttes. It
presents no distinction between gular and humeral scute areas.

Fig. 7. Tbstudo CoRSONi. Anteriorextremityof a plastron, one-half the natural size. From a specimen
discovered by Dr. Corson at Grizzly Buttes.

Fio-, 8. Supposed turtle egg, natural size. A frequent fossil of the indurated clays of the Bridgcr bf'ds.
They are usually about the size of the specimen represented, though quite small ones are
also fonud, like that represented in Fig. 01, Plate XXXII. They have an outer calcareous
crust, and are iilled with the same material as the imhe<ldiug matrix. Usually one end is
truncated and rough, as if the shell had been originally broken. Sometiuies the truncated
end apitears covered with a low conical disk, resembling an operculum, as represented in
Figs. 60, 61, Plate XXXII.

Fi'^ 9. Hybemys arenakius. A marginal plate, exhibiting the bosses ou its outer extension. From
a specimen found by Prt)fes8or Haydeu's party on Little Sandy Creek. Natural size.

Fig. 10. Stylemys OREGONEN.SI8. A vertebral plate, one-half the natural size. From Crooked River,
Oregon.

Figs. 11-13. NoTHOSAUKOPS OCCLDUUS. Three views of a vertebra, natural size, from .i specimen ob-
tained by Professor Haydeu on Moreau River.
Fig. II. Side view of the centrum, exhibiting the sutural surface of the neural arch.
Fig. 12. Upper view of the same.
Fig. 13. View of the anterior end.

Figs. 14, 15. Saniwa. Natural size.

• Fig. 14. Saniwa major. Distal extremity of a humerus, from a specimen found by Dr.
Carter at the Lodge-pole trail, ou Dry Creek, Wyoming.
Fig. 15. Saniwa ensiden.s. Two dorsal vertebrai as they lie iu the matrix, inferior view,
from a specimen obtained near Granger, Wyoming, during Professor Haydeu's exploration.

Figs. lB-18. Antrodemus. In the text, page 267, under the name of Poicilopleuron valens. Figures
one-balf the natural size. Three views of one-half of a vertebra, from Middle Park,
Colorado.

Fjo-. 16. End view, exhibiting the articular surface of the centrum.

Fig. 17. Side view.

Fig. 18. View of the Ijroken surface of the vertebra, exhibiting the large areola^ of the
interior of the centrum, inclosed by thick walls of compact substance.

U. S. G.oological Survey of the Territories

Plate X.V"

„^_

N njk

T. SINCLAIR & SON, PHILADELPHIA

1-5 BAENA ARENOSA, >^
6. BAPTEMYS. >:^.
7 TESTUDO CORSON] ;^
9. HYBEMYS.

10 STYLEMYS yi

11- IS. NOTHOSAUROPS.

14 15. SANIVA

16-18 ANTRODEMtrS. }4

EXPLANATION OF PLATE XVI.

All tbe figures of tlio natural size, except Figs. 13-17.

Figs. 1-6. Ano.steira ohnata :

Fig. 1. Portions of tlio carapace.

Fig. 2. Portion of the same specimen, with portions of tlie plastron. Siiecimens collected

by Dr. Carter in the vicinity of Fort Bridger.
Fig. 3. Inner view of tbrfee oostals, from a portion of the same specimen as Fig. 1, exhibiting

the costal capitula.
Fig. 4. A third marginal plate from a larger individual. Dr. Carter.
Fig. 5. A fourth marginal plate of the left-side of another individual. From Washakia ;

collected by James Stevenson.
Fig. 6. Section of a i^ygal plate. From a specimen found bj' Professor Haydeu at Church

Buttes.
Fig. 7. Ilium of a turtle. Obtained at Grizzly Buttes by Dr. Carter.

Figs. 8, 9. BjuSna arenosa :

Fig. 8. Ilium of the right side, outer view. Fig. 9. Sacrum, inferior view. Sjiecimens ob-
tained from portions of the matrix, pertaining to the specimen of the shell represented in
Figs. 1, 2, Plate XIII.

Fig. 10. Opisthocoelian caudal vertebra of a turtle. From near Lodge-ijolo trail. Dr.
Carter.

Fig. 11. Fragment of a costal plate of a trionyx. From near Fort Bridger. Dr. Carter.

Fig. 12. Fragment of a costal j)lat6 of a trionyx. From Little .Sandy Creek. Professor
Hayden.

Figs. 13-17. Glyptosaxjrus. All magnified two diameters.

Figs. 13-15. Osseous dermal plates of the body. Figs. 16, 17. Plates of the head. From
Grizzly Buttes. Dr. Carter.

Figs. 18, 10. Oligosimus grand.evus :

Fig. 18. Posterior view of a caudal vertebra. Fig. 19. Lateral view. Specimen obtained
by Professor Hayden's party on Henry's Fork of Green Kiver.

JJ. 8. GeologiGal Survey of the Territories

Plate SVI

T SINCHID 1 S.IV IITH PUII HO'

1-6. ANOSTEIRA ORNATA

7. ILnJM OF TURTLE

8, 9 BAENA AREN03A

10 ■'/t:rti _ :• •; . htle
11, 12. ccstals of tfjontx

lS-17 aLYPTOSAURUS.

13, 19 OLIG-OSIMUS GRANDE VUS.

EXPLANATION OF PLATE XVII.

All tbo tigiires of tUo natural size, except Figs. 9, 10.

Fig. 1. Clupea IIU5IILIS. From the original specimen obtained by Dr. John E. Evans, on Green River,
in 1806.

Fig. 2. Clupea alta. From the "Petrified Fish Cut," on the Union Pacific Railroad, near Green River.

Fig. 3. Petalodus allegh-vniensis. Tooth, front view, from a specimen obtained by Messrs. Meek and
Hayden, in the ni^iier carboniferous formation of Fort Riley, Kansas.

Figs. 4-6. Cladodus occidentalis. Tooth found by Messrs. Meek and Hayden, in the upper coal
measures of Manhattan, Kansas.
Fig. 4. Back view. Fig. 5. Section of the crown. Fig. 6. Bottom of the root. .

Figs. 7, 8. PTYcnoDUS occidentalis. Tooth discovered by Dr. John L. Le Coute, in the Cretaceous
formation east of Fort Haj's, Kansas.
Fig. 7. Upjier view. Fig. 8. Lateral view.

Figs. 9, 10. XiPHACTiNUS AUDAX. A pectoral .spine, one-half the natural size.
Fig. 9. Inferior view. Fig. 10. Superior view.

Figs. 11-17. Myi.ocypeinds robustus. Pharyngeal bones, from Idaho, contained iu the collection of

Professor J. S. Newberry.
Fig. 11. Interior view of a left pharyngeal, containing the three intermediate teeth.
Fig. 12. Inferior view of a right pharyngeal, containing the anterior three teeth.
Fig. 13. Same view of a smaller left pharyngeal, with the posterior four teeth.
Fig. 14. Similar view of another specimen, with the anterior three teeth and the bases of

the posterior two teeth.
Fig. 15. Posterior view of a right pharyngeal of an old auimal, with the second aud fourth

teeth.
Fig. 16. Inner view of a right pharyngeal, with the posterior four teeth.
Fig. 17. Posterior view of the same siiecimen.

Figs. 18, 19. Oncobatis pentagonus. Dermal plate, from the Pliocene of Sinker Creek, Idaho.
Fig. 18. Upper view. Fig. 19. Lateral view.

Fig. 20. Enchodus Shujiaedi. Dentary bone, natural size, but reversed iu position. From the Cre-
taceous of Dakota.

Figs. 21, 22. Cladocyclus occident^vlis. Two scales, natural size. Found with the preceding.

Figs. 23, 24. Phasganodus dirus. From Cannonball River, Dakota.
Fig. 23. A tooth of the natural size.
Fig. 24. Dentary bone, reduced one-third.

Fig. 25. Xystracantiius arcuatus. A dorsal spine, from Leavenworth, Kansas.

Fig. 26. Hadrohy^u.s .suprbjius:

The mutilated crown of an upper premolar tooth, natural size, seen on the triturating sur-
face. From the Miocene Tertiary of Oregon.

U S G-eoJo^Teal Survey ol" the Territ':>riefl

flate XVll

r s/»a A/ir * suff iiTH ph'l •

EXPLANATION OF PLATE XVIII.

All the figures are of the natural size except Figs. 51, 5'2.

Figs. 1-14. Ptychodus MoitxoNl:

Figs. 1, 2. Upper and posterior views of a large tootli from Kansas, obtained by Dr. George

M. Sternberg.
Figs. 3, 4. Upper and posterior views of auotber tootb, apparently from the same individual.
Figs. 5, C. Upper and posterior views of another tooth from the same locality.
Figs. 7, 8. Upper and posterior views of another tooth from the same locality.
Figs. 9, 10. Upper and posterior views of another tooth from the same locality.
Figs. 11, 12. Upper and anterior views of a large tooth from near Columbus, Mississippi,

found by Dr. William Sinllman.
Figs. 13, 14. Upper and posterior views of a tooth from Green County, Alabama, obtained

by Professor Joseph Jones.

Figs. 1.5-18. PTYCHonus occiDHNTA'Lis. Specimen obtained near Fort Hays, Kansas, by Dr. John L.
Le Conte.
Figs. 15, 16. Upper and posterior views of a worn tooth.
Figs. 17, 18. Upper views of two small teeth.

Figs. 19, 20. Ptychodus Whippleyi. The specimen obtained in the Cretaceous formation of Texas, by
Dr. Benjamin F. Shiimard.
Fig. 19. Upper view of a tooth.
Fig. 20. Posterior view of the same tooth.

Figs. 21-25. OXYRHINA EXTE.VTA :

Figs. 21-23. Views, external or anterior, of three teeth from the Cretaceous formation of

Kansas, obtained by Dr. George M. Sternberg.
Figs. 24, 25. External v.iews of two teeth, from the Cretaceous formation near Columbus,

Mississippi, obtained by Dr. William Spillman.

Figs. 26-28. Otodus divaricatus. The specimen from Texas, probably from a Cretaceous formation.
Loaned for examination by Dr. William Spillman.
Fig. 2fi. External or anterior view of the tooth.
Fig. 27. Lateral view reversed.
Fig. 28. Internal or posterior view.

Figs. 29-40. Galeocerdo falcatus. External views of teeth.

Figs. 29-31. Specimens from the Cretaceous of Kansas, collected by Dr. George M. Sternberg.
Figs. 32-36. Specimens from the Cretaceous, near Columbus, Mississippi, collected by Dr.

William Spillman.
Figs. 37-40. Specimens from the Cretaceous, near Fort Hays, Kansas, collected by Dr. John

L. Lo Conte.
Figs. 41, 42. Specimens from the Cretaceous of Texas, collected by Dr. Benjamin F. Shumard.
Fig. 43. Specimen from the chalk of Sussex, England.

Figs. 44, 45. Lamna :

Fig. 44. External view of a tooth, from the Cretaceons, near Fort Hays, Kansas, found by Dr.

John L. Le Conte.
Fig. 45. External view of a similar but smaller tooth, from the chalk of Sussex, England.

Figs. 4G-49. Lamna :

Figs. 46, 47. Specimens from the Cretaceous of New Jersey. Fig. 46. Lateral view of a tooth.
Fig. 47. E::terual view of another specimen.

Figs. 48, 49. Specimens from the Cretaceous of Missisnppi, collected by Dr. William .Spill-
man. Fig. id. Lateral view of a tooth. Fig. 4). External view of another tootli.

Fig. .50. Outer view of a tooth. Specimen from the Cretaceous of Kansas, collected by Pro-
fessor Hayden.

Figs. 51, 52. Pal/EOSY<ops paludosos. Oue-half the natural si7,e. -

Fig. 51. Side view of the face; from the same specimen as the teeth of Fig. 3, Plate IV.
Fig. 52. Lower jaw; repeated from the same specimen as Fig. 11, Plate V.

U. S, geological Survey of the Territories

Plate XSnil.

''■■■''^^'i'0^.

ThoK. SmcLuric Soa,.lJftx.Flula.

EXPLANATION OF PLATE XIX.

Figs. 1-4. PaLvEOSYOPS rAi.uDosu.s. All half size except Fig. 4.
Fig. 1. Front view of the left femur.
Fig. 2. Lower extremity of the right femur.
Fig. 3. Distal extremity of the right humerus.
Fig. 4. The right patella, luuer view, natural size. Lodge-pole tr.ail. Dr. Carter.

Fig. 5. Hyrachyus. Au astragalus. Natural size.

Fig. 6. Distal extremity of left femur of Testudo niol/rarensis, one-half the natural size.

Fig. 7. Distal extremity of right humerus of Testudo nebmscensis, from a young animal, half the natural
size.

Fig. 8. Distal extremity of the right humerus of Testudo nioirarensis, half the natural size.

Fig. 9. Portion of a carapace of Tesludo nehrascensis, internal surface exhibitiug the ridge of attachment
of the neural sijines and the narrow costal cajjitula, natural size.

Fig. 10. Portion of right scapula of Testudo neJirascciisis, hack view, one-half the natural size.

Fig. 11. Sacral vertebrae of Clustcrnoit undatum, inferior view, natural size.

Fig. 12. Lateral view of the same.

Fig. 13. Ungual phalanx of an undetermined reptile, one-half the natural size. See page 285.

Fig. 14. Dermal plate of Ti/losteus ornatus, one-half the natural size.

Figs. 15, 16. Pycnodus faba. Natural size.

Fig. 15. Portion of a left ramus of the lower jaw, with teeth. The specimen from the Creta-
ceous formation of Mississijipi,
Fig. 16. Fragment of the left ramus of the lower jaw, with three teeth, from the greensand
of Crosswicks, Burlington County, New Jersey.

Figs. 17-20. Hadrodus priscus, natural size. Specimen belonging to Dr. William Spillman, of Colum-
bus, Mississippi, and found by him in the cretaceous formation of that State.

Fig. 17. Front view of a supposed premaxillary bono, with two teeth.

Fig. 18. Posterior view of the same, exhibiting at the sides the two reserve cavities for suc-
cessioual teeth.

Fig. ID. Lateral view.

Fig. 20. Inferior view.

Figs. 21, 22. EuMY'LODUS LAQUEATUS. Mandible two-thirds natural size. From the Cretaceous forma-
tion of Mississippi, discovered by Dr. William Spillman.
Fig. 21. Inner view ; specimen reversed.
Fig. 22. View of the upper or triturating surface, with the inner surface in xjcrspective.

XJ. S. G.eological Su^'vey of the Territories

Plate X:XX.

rhoB, Sinclair ieSoa. lith.Phila.

EXPLANATION OF PLATE XX.

Fig. 1-7. Paljeosyops paludosus. Figures one-lialf size.

Fig. 1. Tibia of tbe right side, front view. From Grizzly Bnttos. Haydon's collection

of 1870.
Fig. 2. Calcanonm, upper view. Fount! by Dr. Corson on Smitb's Fork of Greeu River.
Fig. 3. Astr.^galus, upper view. Found by Dr. Carter near Miller.sville.
Fig. 4. Cuboid, scaphoid, and osternal cuueiform. From Chnrch Buttes. Haytlcn's collection.
Fig. 5. Metatarsal. Found by Dr. Corsou near Fort Bridger.
Fig. 6. First phalanx. Found by Dr. Carter ou Henry's Fork of Green River.
Fig. 7. Second phalanx. Found by Dr. Carter near Fort Bridger.

Fig. 8. PAL.E0SYOPS MAJOR :

Portion of the right ramus of a lower jaw, one-half size. The specimen is somewhat swollen
and altered in character from disease, and is one of those ui^on which the sjiecies was first
indicated. Discovered by Dr. Carter at Grizzly Buttes.

Figs. 9-11. MERYCOCHOiRUS RU.STICUS. Natural size. From Hayden's collection of the Sweetwater
River.

Fig. 9. Lower extremity of the right tibia, front view.
Fig. 10. Astragalus of the right side, upper view.
Fig. 11. Calcaueum of the right side, upper view.

Fig. 12. Merycochcerus(?) Natural size.

Lower end of the right tibia of a smaller species than the preceding, with the specimens of
which it was found. •

Fig. 13. Hipparion(?) Natural size.

Eight cuneiform bone, ujiper view,*of a small equine animal. Specimen found with the

remains of Merycochaerus just indicated.
Figs. 14-22. Remains from Texas, submitted to examination l>y Professor S. B. Buckley.

All of the natural size.

Fig. 14. HlPPARipN SPECIOSUM (?)

Last upper molar of the right side ; view of the triturating surface. From Washington
County.

Fig. 15. HipPARiON (f)

A third or fourth upper molar of the left side. Found witli the preceding specimen.

Fig. 16. Protoiiippu.s perditus (?)

A second or third upper molar of the right side. From Independence, Washington County.

Figs. 17, 18. PRbTOHIPPUS PLACIDUS(?)

Fig. 17. A third or fourth upper molar of the right side. Found in association with the

specimens of Figs. 14, 15.
Fig. 18. A first upper molar of the right side, probably of the same species as the former.

From Bastrop County.

Fig. 19. ANCiiiTriERiUM('?) australe:

First upper molar of the right side. Found in association with the specimen of Fig. Ifi.

FFg. 20. Protohippos :

A lower molar of the riglit side. From Navarro County.

PLATE XX.

Fig. 21. Procamelus (?)

A first or second upper molar of tho left side, view of thi; triturating surface. Specimen
found iu associatiou with those of Fig. 14, 1.5, aud 17, in Washiugtou Couuty.

Fig. 22. Astragalus of tho left side, upper view, probably of the same species as the last, and found
with it.

Fig. 23. HlPPAI!ION(?) I'AUVIILUS

A coronary boue, or second phalanx, of the natural size. Fonnd at Antelope, Nebraska.

Fig. 24. FeLIS AUGUSTUS ?

Distal extremity of the right humerus, front view, one-half size. Specimen found on tho
Niobrara River, by Professor Hayden. ,

Figs. 25, £6. Hyraciivus aguarius. From a specimen obtained by Dr. Carter at Grizzly Buttes.
Natural size.

Fig. 25. Left ramus of tho lower jaw, containing the back two premolars and the two suc-
ceeding molars.

Fig. 26. View of the triturating surface of the same teeth, with the addition of part of the
second premolar.

n. S. Geci.igical Surtey of the I'trritones

"Plab- XX

Tho «. S incloir & Son , Uth . Phila .

EXPLANATION OF PLATE XXI.

Figs. 1-4. M.\STODON OBSCURDS:

Last lower molar of the left side, natural size. Specimen discovered by Dr. Lorenzo G-
Yates, in Contra Costa County, California, and now in the museum of Amherst College.

Fig. 1. View of the triturating surface.

Fig. 2. Outer view*f the same sjiecimen.

Fig. 3. Fragment of a tusk, two-thirds the natural size, exhibiting the broad band of enamel
indicated by the darljer shade. Specimen found by Dr. Yates in Stanislaus County, Cal-
ifornia, and belonging to Amherst CoUege museum.

Fig. 4. Outline of the transverse section from, the smaller end of the same specimen, of the
natural size.

U. S (;»>oloyioal Survey of thp I'erriLotiuo.

PlateXXI

:,p.

-^■-■■.^^'■'^^■?-^«a>«^"'-.'-' -!;r^i

SIMCLAiH * SO

1 t. MASTODON, CONTRA COSTA COijN"^Y, CAl. | ,3,4 MASTODON, STANISLAUS COUNTY, CAL,

EXPLANATION OF PLATE XXII.

Fig. 1-4. Mastodon obscurus:

Fragments of a lower jaw, from near Santa F6, New Mexico, presented to the Smithsonian
Institution by W. F. M. Arny.

Fig. 1. Portion of the jaw containing the greater part of the last molar tooth. Fig. 2. Por-
tion of the symphysis. The two fragments placed in their relative position, and reduced
to one-sixth the natural size.

Fij;. 3. Inferior view of the symphysial fragment, exhibiting exposed portions of the incis-
ors. One-fourth the natural size.

Fig 4. The last inferior molar, uatur.il size, seen on the triturating surface. The back i)or-
tion, consisting of another division and the heel, are broken away.

Figs. 5, 6. Mastodon AMEin.CANUS. Au anomalous molar tooth, natural size.
Fig. 5. View of the triturating surface.
Fig. G. Side view.

Fig. 7. GitAPHiODON viNKAitius. A tooth of the natural size. Specimen from the Miocene of Slartha's
Vineyard, belonging to the museum of the Smithsonian Institution.

T7. S. GeoloHK^al Survey oT the Temt«ne«

Plate ZXII.

r\y

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.' n

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T*>V

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ThoK. .SinddirJb >bil. JitlL.Ftula..

EXPLANATION OF PLATE XXIII.

All the figures of the iiatui'al size except Fii;. 16, which is one-half size.

Figs. 1, 2. PALiEOSYOPS MAJOR :

Fig. 1. The complete series of molar teeth of the left side of the lower jaw, except the drst

premolar. The second and tliird premolars are reversed from those of the opposite side.

Specimen discovered hy Dr. Carter in Dry Creek Canon, forty miles from Fort Bridger.
Fig. 2. A series consisting of the molars and last two premolars contained in detached

fragments of a lower jaw. Specimens obtained by Dr. Carter ou Dry Creek. Tlie molars

are larger and more worn than in the preceding specimen.

Figs. 3-6. Pai-.s;osyops paludosus. ' Specimens ui>on which the species was originally established.
Hayden's collection of 1870.
Fig. 3. A third lower premolar of the left side.
Fig. 4. A last lower premolar of the right side.
Fig. .5. A first lower molar of the left side.
Fig. 6. Anterior part of a second upper molar of the left side.

Figs. 7-11. Pal^eosyops ma.iok. Specimens found by Dr. Corson in Dry Creek Cauon.
Fig. 7. The left upper canine tooth.
Fig. 8. The second upper premolar of the left side.
Fig. 9. The last upper premolar of the same side.
Fig. 10. The second npjier molar of the same side.
Fig. 11. The last upper molar of the same side.

Fig. 12. Pal^osyops major :

Series of premolars from the second to the last, inclusive, of the right side. From Dry
Creek. Dr. Carter.

Fig. 13. Pai..«:osyops (Limnohyus) i.aticeps(?)

A second upper molar of the right side. A comparatively smooth tooth. Specimen discov-
ered by Dr. Corson, in association with the large canine tooth of Figs. 1-3, Plate XXV.

Figs. 14-10. Pal^osyoes majok:

Fig. 14. A last lower molar of the right side. Contained in a jaw fragment obtained by

Dr. Carter at Dry Creek Canon.
Fig. 15. An inferior incisor, lateral view, belonging to the same individual as the specimens

of Figs. 7-11.
Fig. 16. Upper view of a cranium, one-half the natural size. The specimen discovered by

Dr. Carter at Dry Creek Canon.

U. S. G.eDlogical Surrey of the Tern ton

Plate XXai,

PALAEOSYOPS.

IhoK SiiirldtrJc San. lith.Pliila.

EXPLANATION OF PLATE XXIV.

Figs. 1-5. Pal^osyops major :

Fig. 1. View of a left side of a ccauium, oue-lialf the natural size. Specimen discovered by
Dr. Carter on the bnttes of Dry Creek Canon.

Fig. 2. View of the left side of a crushed facial specimen, one-half the natural size. Speci-
men found by a Shoshone Indian, and brought to Dr. Carter.

Fig. 3. View of the triturating surfixce of a penultimate upper molar of the riglit side,
natural size. From the same skull as Fig. 1.

Fig. 4. Portion of the right ramus of the lower jaw of the same animal, one-half the natural
size.

Fig. .5. Au upper lateral incisor, natural size. Specimen found by Dr. Corson in the buttes
of Dry Creek Canon.

Figs. 6, 7. Pal^osyops paludosus (?) Natural size.

Fig. 0. Fore part of the upper jaw, containing the first three premolars and part of the fang

of the caniuft.
Fig. 7. Triturating surfaces of the premolars.

Fig. 8. Paljeo-Syops humilis :

A last upper molar of the left side, natural size. Found by Dr. Corson on the buttes of Dry
Creek Canon.

;. a G;eoJogieal Survey ol' lLo IViritories

Plate XXTV.

ThV SiHcUjr * SoB.PinJa.

PAL AEO STOPS.

EXPLANATION OF PLATE XXV.

UiNTATiiEniCM ROBUSTUM. All the Specimens discovered by Drs. Corson and Carter at Dry
Creek Canon. Natural size, excei)t Figs. 8 and 11, which are one-half size.

Figs. 1-5. A supposed upper canine tooth. Discovered by Dr. Corson in comj)any with a fragment of the
same tooth of the other side, the specimen reprcsente<l in Figs. 13, 14, and the molar of
Palajosyops represented in Fig. 13, Plate XXIII. Originally referred to a supposed car-
nivore, with the name of Uiniamastix atrox.

Fig. 1. Outer view of the right canine. The restored outline of the lance-head-like point
is, perhaps, a little exaggerated.

Fig. 2. Inner view of the point of the same specimen.

Fig. 3. Front view.

Fig. 4. Outline of a transverse section of the lance-head-'like point.

Fig. 5. Outline of a section near tho base of the specimen.

Figs. 6-12. Specimens found together, with portions of the skull and other boues of the skeletou, ten
miles distant from the former. Discovered by Drs. Carter and Corson.
Fig. 6. Inner view of tho last upper molar of the right side.
Fig. 7. View of the triturating surface of the same tooth.

Fig. 8. Outer view of the same tooth inserted in a jaw-fragment, half the natural size.
Fig. 9. Inner view of the last lower molar of the right side.
Fig. 10. View of the triturating surface of the same tooth.
Fig. 11. Outer view of the lower-jaw fragment, containing tho same tooth, one-half tho

natural size.
Fig. 12. Triturating surface, much worn, of the first upper molar, of tho right side.

Figs. 13, 14. A supposed upper jiremolar of the same animal. Discovered by Dr. Corson in company with
the large canine tooth of Figs. 1-5.
Fig. 13. Inner view of the tooth.
Fig. 14. Triturating surface.

V S ^eol'JbT-cal burveT' uT t}it; Ten;'

Plate >;XY.

UINTATHERIUM

Tho«.Sl,..l.„ri<S..n-l.lk.Pli>>a.

EXPLANATION OF PLATE XXVI.

Figs. 1-8. UlNTATHERIDJI ItOBUSXUM :

Fig. 1. "View of the right side of a mutilated cranium, one-half the diameter of nature. Spec-
imen upon which the genus was characterized. Discovered by Dr. Carter about fifty miles
from Fort Bridger.

Fig. 2. An atlas, of the same species. Inferior view, one-fourth the diameter.

Fig. 3. A right humerus. Found by Dr. Carter in the same locality as the specimen of Fig. 1.
Anterior view, one-fourth the diameter.

Fig. 4. Proximal extremity of a femur, probably pertaining to a larger species of the same
genus, or perhaps to a larger variety. One-fourth the diameter.

Fig. 5. Distal extremity of another femur, probably of U. robustmn. One-fourth the diameter.

Fig. 6. Calcaneum of the left side. Upjier view, one-half size.

Figs. 7, 8. Astragalus, one-half size.

Fig. 7. Upper view. Fig. 8. Inferior view.

Figs. 9, 10. Hyrachyus EXinnus :

Left lower iienultimate molar tooth, natural size.

Fig. 9. Outer view. Fig. 10. Upper view.

Fig. 11. Hyrachyus nano.s :

Right ramus of the lower jaw, retaining the back four molar teeth. Natural size.

tf. 'S. Geological Survey of the Territories

Plate XXVT

■ni" sir.cUirftSon.Piiila.

1-8 UINTATHERIUM. 9-11 HYRACHYUS .

EXPLANATION OF PLATE XXVII.

Figs. 1, 2. HiPPOSYUS FOIiMOSUS :

Au upper luolar tootb, probably tbo seoouil true molar of tbo loft sido, maguified tbroe

diameters.
Fig. 1. Outer view of the crown.
Fig. 2. View of the triturating surface.

Figs. 3, 4. Wash.\kius insignis :

Fig. 3. Portion of tbo rigbt ramus of tbo lower jaw, containing tbo last two molars, magni-
fied three diameters.
Fig. 4. View of tbo triturating surfaces of the teeth, magnified eight diameters.

Fig. 5. HYOP.SODUS MINUSCULOS :

View of tbo triturating surfaces of the last premolar and the molars of the left side, m.agni-
fied four diameters.

Figs. G-10. UixTACyoN edax :

Fig. C. Right side of the lower jaw, containing the intermediate three premolars, part of the
first molar, and the second molar, natural size.

Figs. 7-10. The teeth, magnified three diameters.

Fig. 7. Triturating surface of tbo second molar.
Fig. 8. Outer view of the same tooth.
Fig. 9. Upper view of the premolars.
Fig. 10. Outer view of the same.

Figs. 1 1-13. UlNTACYON VORAX :

Fig. 11. Fragment of the left side of the lower jaw, containing part of the first molar and

the second molar, natural size.
Fig. 12. lTi>per view of the secoud molar.
Fig. 13. Oater view of the second molar.

Figs. 14, 15. Mysops featernus :

Fig. 14. Eight side of lower jaw, with tbo last three molars, maguified two diameters.
Fig. 15. View of the triturating surfaces of tbo molars, magnified eight diameters.

Figs. 16-18. Paramys delicatior :

Fig. 16. Lower molar of the rigbt side, the second or third of tbo series, seen on tbo tritu-
rating surface, magnified three diameters.

Fig. 17. U[)per molars of the same animal, ajipareutly the intorraediatc pair. Outer view,
magnified three diameters.

Fig. 18. View of the triturating surfaces of the same teeth, maguified three diametens.

Figs. 19, 20. MiCROSY'OPS (?)

An upper molar tooth, magnified four times.

Fig. 19. Outer view.

Fig. 20. View of the triturating surface.

Figs. 21, 22. Hyraciiyus nanus (?)

A last upper premolar, magnified two diameters.

Fig. 21. Outer view.

Fig. 22. View of the triturating surface.

PLATE XXVII.

Fig. 23. Fragment of tbo left side of the lower jaw, coutainiug two premolars, apparently the third and
fourth, of au undetermined carnivore, natural size. From the Bridger Eocene of Wyo-
ming.

Figs. 24, 25. Megalomeryx niobrarensisC?) A lower molar tooth, natural size. From the Tertiary of
L'Eau qui Court County, Nebraska. Sjiecimeu in the museuin of Swarthmore College.

Fig. 24. Triturating surface.
Fig. 25. Outer view.

Figs. 26-29. PROCA.MELUS viRGiNiENSis. Natural size. Specimens from the Miocene of Virginia, and
belonging to Mr. C. M. Smith, of Richmond, Virginia.
Fig. 26. Outer view of the last lower molar of the right side.
Fig. 27. Triturating surface of the same.

Fig. 28. The last premolar and first molar of the right side, outer view.
Fig. 29. Triturating surfaces of the same.

Figs. 30-34. Uesitatherium robostcm :

Fig. 30. Last upper molar of the right side, (juter view, natural size.

Fig. 31. Last lower molar of the right side, outer view, natural size.

Fig. 32. Portiou of the left ramus of the lower jaw, one-half the natural size. . Fig. 33. Mu-
tilated corouoid and condyle of the same specimen as the former.

Fig. 34. Upper view of the atlas, from the same specimen as Fig. 2, Plate XXVI, one-fourth
the diameter of nature.

Fig. 35. Saniwa ensidens. Tooth magnified eight diameters.

Figs. 36,37. Saniwa major:

Two dorsal vertebra?, natural size.
Fig. 36. Inferior view.
Fig. 37. View of right side.

Figs. 38, 39. Chameleo pristin0S. Fragment of the lower jaw, magnified three diameters.

Fig. 36. Outer view.

Fig. 39. Inner view.

Fig. 40. Undetermined tooth of a reptile, magnified two diameters. From the Bridger
Eocene formation of Wyoming. It may be the tooth of a crocodile or a lacertian. It is
an isolated specimen, partially imbedded in a greenish sandstone, with fresh-water shells.
The crown is compressed mammillary, and strongly striate, from an acute-bordered summit.

n. S. Geological Survey of the Territories

Plate XXVU.

d^^

liiV Sinclair tSon,Eltfla

EXPLANATION OF PLATE XXVIII.

Figs. 1, 2. UlNTATHEUIUM KOBUSTOM :

Fig. 1. Outline talieu from Professor Marsh's Fig. 1, Plate II, of Dinoceras mirahilis, iu the
Am. Jour. Science, 1873, enlarged so as to accord with one-sixth of the size of the frag-
ments introduced iu the figure, which corresi^ond with those of Figs. 1 and 8, Plate XXV,
and Fig. 1, Plate XXVI.

Kg. 2. View of the base of the cranial specimen also represented in Fig. 1, Plate XXVI.
One-sixth the diameter of nature.

Fig. 3. Large osseous i>rotuberance, one-half the size of nature, resembling the similar
osseous protuberances of the specimen of Megaccrops, represented in Figs. 2, 3, Plate 1.
The specimen is from the Mauvaises Terres of White River, Dakota, and was originally
suspected to belong to Titanotherium.

Figs. 4-8. Bison latifrons:

Figs. 4, 5. Cranium from Pilarcitos Valley, California, discovered by Messrs. Calvin and
Wilfred Brown, and presented to the Academy of Natural Sciences of Philadeli^hia. One-
fifth the natur.al size.

Fig. 4. Upper view. Fig. 5. Posterior view.

Figs. 6, 7. The second and last npper molars seen on their triturating surfaces. Natural size.
Specimens from California, belonging to Wabash College, Indiana.

Fig. 8. An upper second molar of the left side, considerably worn, and seen on its triturat-
ing surface. Natural size. From Luzerue County, Pennsylvania.

Fig. 9. Mastodon americanxjs:

A first lower premolar of the right side, natural size. Found with the iirecediug.

rr S. Geological Survey of the Temtones.

Plate XXVm

g^,.

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V-~i..rr.r-.

''■'■<^m

Wt'-.!-

Ih? SmcUul it Soi\ iith . flu la .

EXPLANATION OF PLATE XXIX.

All the figures one-balf the natural size.

Fig. 1. TkIOXYX UlNTitENSIS :

The nearly entire carapace or upper shield, partially represented. Specimen discovered by
Major Kobert S. La Motte, in the buttes of Dry Creek, ten miles from Fort Bridger, and
presented by him to the Academy of Natural Sciences of Philadelphia.

Figs. 2-4. Testudo Uoksoni:

Specimens discovered by Dr. Joseph K. Corson, in association with portions of the plastron,

and the specimen of the carapace represented in Fig. 1, Plate XXX.
Fig. 2. Anterior view of the proximal extremity of the right humerus.
Fig. 3. Outer view of the same specimen.
Fig. 4. Distal extremity of the right femur, front view.

Fig. 5. Paljeosyops paludosus:

Femur of the left side, anterior view. Specimen obtained by Dr. Carter on Grizzly Buttes.

U.S. CeologicalSurveTof il'.^ Terntori.e.'!

Plate XXK.

fetiiii^ l'^ ' ^ ^'

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A .9

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iTRlONYXUlNTAENSrS. 2^4TESTUD0 CORSONI . 5.PAIJ\K0SYOHS PALUDOSUS-

EXPLANATION OF PLATE XXX.

Figs. 1-4. Testudo Coksoni :

Fig. 1. Intermeilinte portion of tbo carapace, one-half the natural size, exhibit-inn; the series
of vertebral jilates, from the first to the eighth and part of the ninth, and contiguous por-
tions of the costal plates. Specimen cliscovered by Dr. Joseph K. Corson on the buttes of
Dry Creek, and jux'sented hy him to the Academy of Philadelphia.

Fig. 2. Plastron, or lower shield, one-third the natural size. Specimen discovered by Dr.
Corson ou Grizzly Buttes, and presented to the Academy.

Fig. 3. Anterior i)rocess of another plastron, one-half the natural size. From a specimen
discovered by Dr. Corson in the same locality as the last.

Fig. 4. Anterior process of a nearly complete plastron, one-half the natural size. From a
specimen discovered by Mrs. Dr. Carter on the buttes of Dry Creek, and presented by her
to the Academy of Philadelphia.

I'ig. 5. CLADOCYCLUS OCCIDENT^iXlS :

Large scale, imbedded in a lead-colored calcareous shale, natural size. Specimen obtained
by Professor Hayden from the Cretaceous formation of Sage Creek, Dakota.

U S Geological S uivey of the Terrilories

Plate XXX.

IV; Sircliui 4 Soo.PlDJa.

1-4 TESTUDO CORSONI.

5. CLADOCYCLUS.

EXPLANATION OF PLATE XXXL

Fig. 1. Eestorecl skull of PaJocosyops. The cranium ami face arc introduced from the specimens of
Figs. 1, 2, Plate XXIV, and Fig. 51, Plate XVIII; and the lower jaw from the specimen of
Fig. 52 of the latter plate, and Fig. 4, Plate XXIV. About half the natural size of the
skull of P. paludosus.

Fig. 2. Canis indlvnensis :

Right ramus of the lower jaw, one-half the natural size. Specimen from San Leaudro, Cali-
fornia. Discovered by Dr. Lorenzo G. Yates, and now in the museum of Wabash College,
Crawfordsville, Indiana.

Fig. 3. FeLIS IMPBRIALIS :

Fore part of the upper jaw, with the second premolar, one-half the natural size. Accom-
panying the preceding specimen.

Fig. 4. LuTRA pisciNjVRia:

Tibia of the right side, two-thirds the natural size. From Sinker Creek, Idaho, and belong-
ing to the Smithsonian Institution.

'Z . S- G.eoJogical SurvsY of the Terntonee

Plate XXXI .

Th'» aiidaii & Son. liUi . Phila

EXPLANATION OF PLATE XXXII.

All tbc figures of the natural size.

Figs. 1-G. Ajiia (Pcotamia) uintaensis:

Fig. 1. Centrum of .1 dorsal vertebra, auterior view. Fig. 2. View of the same beneath.

From Dry Creek Canon.
Fig. 3. Centrnra of an atlas, auterior view. Fig. 4. Inferior view of the same. From Dry

Creek Cauou.
Fig. 5. A series of three posterior dorsal centra, inferior view. From Dry Creek Canon.
Fig. 6. Basi occipital, posterior view. Fig. fia. Inferior view of the same. From Dry Creek.

Figs. 7-11. Amia (Pkotamia) media :

Fig. 7. Centrum of a dorsal vertebra, upper view. Fig. 8. Posterior view. Fig. 9. fcferior

view. Junction of Sandy and Green Elvers.
Fig. 10. Centrum of a posterior dorsal vertebra, back view. Fig. 11. Inferior view. Dry

Creek.

Figs. 18, 13. Lepidosteus notabilis:

Fig. 12. Centrum of a dorsal vertebra, inferior view. Fig. 13. Posterior view. From near
Washakie, Wj-oming.

Figs. 14, 15. Lepidosteus atkox :

Fig. 14. Centrum of an auterior dorsal vertebra, inferior view. Fig. 15. Posterior view.
From the junction of Big Sandy and Green Rivers.

Figs. 16, 17. Lepidosteus (?) See page 190.

Fig. 16. Centrum of a posterior dorsal vertebra, seen beneath.
Fig. 17. Posterior view of the same.'

Fig. 18. Lepidosteus simplex:

The basi.occipital and three vertebral centra, scon beneath. From near Washakie Station,
Wyoming.

Figs. 19-22. Hypamia elegans. A vertebral centrum. From Dry Creek.

Fig. 19. Upper view. Fig. 20. Lateral view. Fig. 21. Posterior view. Fig. 22. Inferior

view.

Figs. 23,24. Amia (Protamia) cnAClLis. A centrum from near tho middle of the dorSl scries. Henry's
Fork of Green Elver, Wyoming.
Fig. 23. Posterior view. Fig. 24. Inferior view.

Fig. 25. Lepidosteus (?)

Fragment of the right dentary bone. See jiage 190.

Fig. 26. Lepidosteus simplex. A tooth. See page 191.

Figs. 27-30. Lepidosteus (?) Scales from Big Sandy and Green Eivor.

Figs. 31-34. Lepidosteus simplex. Scales. From near Washakie Station. See page 191.

Figs. 35-38. Lepidosteus. Scales. Little Sandy Creek. See page 192.

Figs. 39-42. Lepidosteus. Scales. Near Fort Bridger.

Fig. 43. Lepidosteus. Scah^. Sco page 192.

PLATE XXXII.

Figs. 44-4G. PlMELODU.S ANTIQUUS:

Figs. 44, 45. Fragments of iieotoral spines.

Fig. 4G. Portion of a dentary bone, seen from bouoath.

Figs. 47-51. Phaeeodus acutus. Jaw fragments, from the junction of Big Sandy and Green Rivers,
Wyoming.
Fig. 47. Portion of tlie right xiremaxillary.
Fig. 48. Portion of left jiremaxillary.
Fig. 49. Portion of right dentary.
• Fig. 50. Portion of left dentary.

Fig. 51. Portion of a maxillary.

.Figs. 52, 53. Trygon (?). Caudal spine of a Eay, From the Miocene of Virginia. Fig. 52. Anterior view
of basal portion of the spine. Fig. 53. Section of the same. Belonging to Mr. C. M. Smith.

Figs. 54, 55. Myliobates (?). Caudal spine. Found with the preceding.
Fig. 54. Anterior face of basal portion.
Fig. 55. Section of the same.

Figs. 56, 57. Pkotautoga conidens :

Portions of premaxillaries, with tooth, from tbc Miocene of Virginia. Belonging to C. M.

Smith.
Fig. 56. Fragment of the left prcmaxillary, eoutaiuiug the lirst tooth.
Fig. 57. Right premaxillary, inner view, exhibiting, besides the outer row of large teeth, an

inner row of small ones.

Fig. 58. ACIPfiNSER ORNATUS:

A dermal plate. From the Miocene of Virginia. Belonging to Mr. C. M. Smith.

Fig. 59. AsTERjiCjUStTIIUS SIDERIUS:

Basal portion of an ichthyodorulite, lateral view.

TJ. S Geological Survey of the Territories.

Plate XXXE -

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EXPLANATION OF PLATE XXXIII.

All the figures of tho uatiiial size.

Figs. 1, 2. Equus occidentalis :

Fig. 1. The anterior four upper molars of the left side, seen on their triturating surfaces.

The teeth are contained in a jaw-fragment, obtained by Dr. George H. Horn from an

asphaltum deposit near Bueua Vista Lake, California.. Specimen in the museum of the

Academy of Philadelphia.
Fig. 2. A second upper left molar, seen on the triturating surface. From Tuolumne County

California.

Figs. 3-18. Equus major:

Figs. 3, 4. A first upper molar tooth of the right side. Fig. 3. Outer view. Fig. 4. Tritu-
rating surface. Specimen from Hardin County, Texas.

Figs. 5, 6. A first upper molar of the right side. Fig. 5. Outer view. Fig. 6. Triturating
surface. From Illinois Blufl's, Missouri.

Figs. 7, 8. A last upper molar of the right side. Fig. 7. Outer view. Fig. 8. Triturating
surface. From Hardin County, Texas.

Fig. 9. A last lower molar of the left side, view of the triturating surface. Found with the
last.

Fig. 10. A fifth lower molar of the left side, triturating surface. Found with the last.

Fig. 11. A second or third upper molar of the right side, triturating surface. From Galves-
ton Bay, Texas. Presented to the Academy by Dr. Tbomas H. Streets.

Fig. 12. A first lower temporary molar, triturating surface. From Hardin County, Texas.

Fig. 13. An upper last temporary molar of the left side. Found with the last.

Fig. 14. An upper second or third molar of the left side. From the "phospbate beds" of
Ashley Eiver, South Carolina.

Fig. 15. A second or third lower molar of the right side. From the same locality as the last.

Fig. 16. An upper second or third molar of tho right side. From Luzerne County, Pennsyl-
vania.

Fig. 17. A second lower moUir of the left side. Found with the last.

Fig. 18. An upper fourth or fifth molar of tlie left side. From Texas.

Fig. 19. Equus. Portion of an upper molar of the left side of an undetermined species. From the lignite
beds of Shoalwater Bay, Washington Territory. ,

Figs. 20, 21. Two phalanges of undetermined animals, both fuund, in association with the equine and
other remains, in an asphaltum deposit in Hardin County, Texas. They are both satu-
rated with bitumen. Fig. 20. Lateral view of the specimen. Fig. 21. Inferior view of
the second specimen.

U. S. ^trolo^.oal Siirvpy cf the TerritoTiei*

Plate xxxnr.

Th" Sindaii i Son, lith . Phila

EXPLANATION OF PLATE XXXIV.

All the figures two-thirds the size of nature except Figs. 12-22, wliicli are of the uatural
size.

Figs. 1 to .5 and 10. Clid.vstes iNTERMEDins. From the Cretaceous of Alabama. Museum of the Acad-
emy of Natural Sciences.

Fig. 1. Outer view of the fore part of the left mandible.

Fig. 2. Back part of the right inaudible, outer view reversed.

Fig. 4. Reserve tooth, concealed in the excavated base of the last of the series in the speci-
men of Fig. 1, seen from within.

Fig. 5. Reserve tooth, concealed in the excavated base of the second of the series of the same
specimen, seen from within.

Figs. G to 9 and 11. Clidastes affinis. From the Smoky HiU Eiver, of Kansas. Belonging to the mu-
seum of the Smithsonian Institution.
Fig. 6. Outer view of the left mandible.

Fig. 7. Inner view of back part of the right mandible, exhibiting the glenoid articulation.
Fig. 8. Upper view of two fragments of the cranium.
Fig. 9. The basi-spheugid bone.

Fig. 10. C. Intekmedids. The axis seen below and with the fore part downward.

Fig. 11. C. AFFINIS. The left humerus, posterior view.

Fig. 12. Lestosaurus coryph^us:

Greater portion of a palate-bone, with teeth, natural size. From the Smoky Hill Eiver,
Kansas.

Fig. 13. CuDASTES AFFINIS. Tooth contained withiii a jaw-fragiueut. From Smoky Hill Eiver, Kansas.

Fig. 14. Crown of a similar tooth. From L'Eau qui Court Countj', Nebraska. It is compressed, conical,
curved, with acute borders and smooth surfaces. Fig. 15. Section of the same tooth.

Figs. lG-22. Teeth of mosasauroids, natural size, together with the iireceding specimen from L'Eau qui
Court County, Nebraska. Presented to Swarthmore College by George S. Truman.

Fig. 16. Crown of a shed tooth, with striated enamel. Fig. 17. Triinsverse section of the
same, at the base.

Fig. 18. Shed crown of a largo tooth, with'striatcd enamel, anterior view.

Fig. 19. Shed crown of a tooth, with distinct subdivisioual jilaues. Fig. 20. Outlhics of sec-
tions of the same at the base and above the base.

Fig. 21. Crown of another shed tooth, intermediate in character with the two jjreoeding.
Fig. 22. Outline of a section of the same at the base..

U- S. G;eolosical Survey of the Terntonea

Plate XKXIV.

ThI'ShickuiS.San hth.ri:i

EXPLANATION OF PLATE XXXV.

All tho figures oue-lialf the uatural size except Fig. 14, which is of the natural size.

Figs. 1-11. Tylosaurus dyspblor. • Specimens from the Cretaceous of New Mexico, and helonging to
the Smithsonian Institution.

Fig. 1. Ai'ticular ball of a posterior dorsal centrum.

Fig. 2, 3. Tho same of two other specimens, exhibiting a successive increase of compression

from above downward.
Fig. 4. Articular ball of a caudal centrum.
Fig. 5. Left lateral view of the same.

Fig. 6. Articular ball of a more posterior caudal centrum. *

Fig. 7. Left lateral view of the same specimen, exhibiting the reduction iu the size of the

diapophysls. >

Fig. 8. Left lateral view of a more posterior caudal vertebra, devoid of diapophyses.
Fig. 9. Supijosed femur, posterior view.
Fig. 10. Supposed fibula.
Fig. 11. Supposed tibia.

Figs. 12, 13. Tylosaukus proriger. Specimens from the Cretaceous of Kansas, belonging to the
Smithsonian Institution.
Fig. 12. Extremity of the snout, or of the premaxillary.

.Fig. 13. Posterior articular surface of the left spleuial bone of the lower jaw.
Fig. 14. Tooth of a mosasauroid, uatural size, from tho Cretaceous of L'Eau qui Court
County, Nebraska. The crown is compressed, conical, with acute borders and smooth sur-
faces. The base is compressed oval, and it exhibits on its inner side a small concavity for
the accommodation of a successor.

^ K C'eoloni' al Harvey of the T

erntones.

rlateXXXY

Ih" Sindau&Sonhth.nnla

EXPLANATION OF PLATE XXXVI.

Figs. 1-3. Tylosaurcs proriger:

Figs. 1,2. A caudal vertebra, one-half the natural size. From the Cretaceous of Kansas.

Smithsonian lustitution.
Fig. 1. Left lateral view. Fig. 2. Posterior view.
Fig. 3. A tooth which accompanied the former specimen, lateral view, natural size.

Figs. 4-14. Lestosaurus corypii^us. All the figures one-half the natural size. From the Cretaceous

of Kansas. Museum of the Smithsonian Institution.
Fig. 4. Inferior view of a dorsal vertebra. Within the position of the right zygapophysis a

rudimental zygosphene is observed.
Fig. 5. Inferior view of a second specimen.
Fig. 6. Inferior view of the body of a cervical vertebra.
Fig. 7. Right lateral view of another cervical vertebra.
Fig. 8. Left lateral view of an anterior caudal vertebra.
Fig. 9. Same view of a more posterior specimen.
Fig. 10. Posterior view of the same.

Fig. 11. Left lateral view of the bodies of two posterior vertebraj.
Fig. 12. Posterior view of the second of the latter.
Fig. 13. Limb-bone, jirobably an ulna or a fibula.
Fig. 14. Probably a radius or a tibia.

Fig. 15. MosASAURUs:

A caudal vertebra, from L'Eau qui Court County, Nebraska. Museum of Swarthmore Col-
lege. Presented by George S. Truman. Inferior view one-half the natural size.

Fig. 16. Tylosaurus dyspelor. Inferior view of the same caudal centrum as that of Fig. 4, of the

preceding i)late. Half the natural size.
Figs. 17-21. Limb-bones of a turtle, from the Cretaceous of Smoky Hill Eiver, Kansas.

Smithsonian Institution. Three-fourths the natural size.
Fig. 17. Upper extremity of the right humerus, anterior view.
Fig. IS. The right femur, anterior view.
Fig. 19. Portion of a left scapnla, inverted in position. The broken process to the loft is

the precoracoid. Posterior view.
Fig. 20. Portion of the coracoid. The articular surface at the upper end is for the scapula.
Fig. 21. Portion of an undetermined limb-bone. •

S ■.-;■ ~'lt)6^f^3-l 'Survey of tbe Terntonfts

Plate XXXyi

'VW^ Smclait & Son, litli . iTi-ui

EXPLANATION OF PLATE XXXVIl".

Figs. 1-3. AociiEXiA iie.sterna:

Spceimeus from the Quaternary of California, and belonging to the cabinet of Wabasli

College, Crawfordsville, Indiana.
Fig. 1. Outer view of tlie series of lower molar teeth of the left side, one-half the natural

size.
Fig. 2. Triturating surfaces of the same series, natural size.
Fig. 3. A second upper molar of the left side, view of the triturating surface, natural size.

Fig. 4. Bison:

Last lower molar of the left side, triturating surface, natural size. Specimen fonud with
remains of Mcgalonijx Jeffersoiii, in Illinois.

Fig. 5. AciiODU.s iiuMius. Magnifier; one and a half times. A'iew of the tritnrating surface of a tooth.
From the Cretaceous of New Jersey.

Figs. G-12. I'.D.U'iioDox MiKiFicu.s. One-half the natural size. Specimens from the Cretaceous of New
Jersey, and belonging to the cabinet of Rutgers College, New Brnnswiek, New Jersey.
Fig. fi. Tlie mandibles seen on tlieir oralsurt^iee.
Fig. 7. Outer view of the left niandiljle.
Fig. 8. Inni'r vicT of the left mandible.

Fig. 9. Posterior outline of the same, -witli outlines of the dental columns. .

Fig. 10. The maxillaj seen on their palatine or oral surface.
Fig. 11. Outer view of the left nuixilla.
Fig. 12. Posterior outline of the same, with outlines of the dental eohunns.

1 igs. V^, II. Ef.MVLODUS L.iQUKATL'.S :

Left lower maxilla, one-half the natural size.
Fig. 13. Oral surface, exhibiting the dental tubercle.

Fig. 14. Outer view. Specimen from the Cretaceous of Missi.ssippi, and discovered by Dr.
William Spilhnan.

Fig. 10. PoXTOBASiLEU.s TUHEi;crLATU.s. Fragment of a tjoth, with restored outline, natural size.

Figs. If), IT. M.VNATCS INOKN.VTITS. A lower right molar, natural size. From the phosphate beds of
Ashley Eiver, South Carolina.
Fig. 16. Upper view.
Fig. 17. Outer view.

Figs. 18, 19. Pycxodus uobustus. Tooth of the natural size.
Fig. 18. Triturating surface.
Fig. 111. Posterior view. Specimen from the Cretaccons of Neu- .Jersey.

D S. G;eolo6ica.l Survey ol' the Territories

Plate JGCXYII

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