&'f> <:m:WiK;:'.y.i:it '^^^^«^^^^,^, -^^A^A-A,^ 1, '■■'■' n,ri'\A^i : •■ - I 1 f ' < i| 1 1 ,1 y .; n ■' t 1,^.1 j_ ,1 ■.,- . ■- ''^'^AAA. -M^^f IK ' ' ' ' I '' f) ™,\%/^.n^fl. Wm:^^:. ' :--mm^ym - ."■■■■■■•"-. r^sA, WA^ ■■''"mm ,%^ft^flfl5 JJ«TJ«UM.TT ' bitt^ii^ii^w«iy.u-y - 1 if ' MiMJj^JM fmmm tmm'^A.iJ':;i 5>»«^: ■UT UWf.T TT-T ,^^,^n^«i^«,«a,?^ iu.ucmrm ^^^AAA .*1^ iwiiiiwi. I.I I I ■: I r rhW.'^l W-LL(JT.fTJJ »««««, 9aM^^^ ^•'^'^OMr^Af^mr i::>*-*^. iM"*'' V'^/^/^AOAaA, 'if TTUJifififif/iMiiubCIS mf^^U:f\^^^^' ■'mV't'/^Km Llj^U vis^^yiK^^^C^ -'^ V-^'W/ia^^/^A, ^A^/^A^n/in^^^r %^^^M- i^^?^i^^L^'.a^.®^: 'mm^ ■Mfm^^&^m^ ^^^^MJrSr^. Wmi^^^A ,[^0^/^ .,„MPWP? '^'^^^f 'J[JjA]tllJJJdMMinJaIuIi!MJmuJlMm6hHm -:j.H^'''^:';';''.^,^; *«A^<^*/» llHAWfikWJr Mi^^^^^hf\^i^ '''^^^/•^^^'v^'-'Aft^^ ■ r/^^ /^ ' , 'a^AA'^.A/i^ ;AA^^^;^^?^' jf^y^'^/^^' Ai^A^AAAA /f?^ 1^'^ 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. ^f "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 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. 16 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 17 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. 18 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. 20 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 21 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. 22 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. 23 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 24 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, 25 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 26 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. 27 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 28 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 29 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 30 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 31 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, 32 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- 35 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, 36 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 28 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. 5 G 7 10 12 1(3 17 Transverse. Lines. 3 7 8 lOi 13 17 m Antero- posterior. Lines. 7 8 8 8 12 15 17 Transverse. Lines. 4 7 9 10 12i W IGJ Lines. Lines. Length of faug of upper canines Autero-posterior diameter of canines Transverse diameter of canines 28 12§ m 18 7 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- 37 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 38 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 39 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. 40 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 41 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 42 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. 43 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 u 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 44 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 45 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^ 46 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. 47 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 48 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 9 5 8^ 7 13i 9 ICi m 24 13i Lines. 08 51 8 G 8a 13i ICJ wl 22 12 Paliposyops paludosus. Lines. 32 23 13 lOi ?77 64 4GJ 8.i 5i 9 6:} 12i s" 15 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 40 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 anor- li(ni of the opposite side is represented in Fig. 4, Plate XXIV. It agrees in T DO 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|)resentea,rt of List iiiohir . . - 14 Tjveadtli of last molar tooth 10 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- 56 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. 57 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 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. 48 55 39i ■10 8 9 54 «i 10 12^ 12 15 17 19 7 9i 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 58 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. 59 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. 60 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 61 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. 62 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 63 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. 64 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 65 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 28 42 24 13 IS 15 13 10.J Liucs. 44 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. 20 Lines. 42 19 24 Lines. 44 20 2U 9g 66 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. u- 5^ 8i Transverse. IjUK'S. 2.i u Tj'uiv 2i- 3i 4 5 5 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. IS ^^ 9 7 7 53 5.> 4 Gi • 5 7 51 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 68 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. Lines. 2i 3i -h n "4 4 3 4.1 H H H 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 G9 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 70 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^ 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 92 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- 93 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 94 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 95 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 96 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 97 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 98 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 e 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 no 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, 15. ^ 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. rp 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 s •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 torders 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. 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Hci o CO tr o- <^> :r O) -t t- -; CO -f t^ o CJ '^ n -3 (M C- '-' ot ^ (» O CO oc GC ^ OJ i^ '^ -H ,- 00 ^5 O OJ O O o .— 1 1— 1 1- & (M '■3 CO "3 tM c^ r-H OT ,-( 1—1 o ^ 00 ^ T-H IC o ^-5 (?J ,-H ?? ■O Oi CO C" c CO O" O C" 00 r- ^ a 2 GO 0. t- t^ 0, _£3 U ' ^ c c p. O c >, 13 .a o ,3 > c '3 ;^ "=3 s S s i? c 1'£ > ■i c '5 o tn o CO <^ O a a gular scutes at inner gular scutes in front humeral scutes iuteri CS o: a ": c cfi .a i S = 1 ^1= g ^ 11 1 ° .9 -« i| 1 2 o o a a "3 a, S c ^^ § z CO a: c en CO 'Pi 1 i GO r- .2 a 1.3 •3 ° =5 o "s ■= o o o '^ Z ^ S 3 - -3 -: _ J .a 5 -S -f r= - ^ :3 -a :3 c; «■! «i 0) s to ^5 t 0 S M s to ;5 tc S to :i a o a i a g a g a g a V a o a § « ^. (D Q ;.! 0^ t- O [-. O fcH « ^ hj n t^ H I-) « h^ n .»-5 pq 1-3 M h-3 M Hi ;^ ^ "*<» ^ o o feq li -a • ^^ w t^ OJ Li^ i^ !-i M U O t/J OJ n3 05 CO -t= s? n ^1 8 2 « C^ f-* ^ 01 s ^< .j-i t*^ fli o r^ H n) kK •f<> . 5^ tq o 3 c-i lO .^ o lC t^; :zi 05 ^ ^ ^ 05 fcq r/J o n) -* ^ 20 G 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. o^ 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 46 48 50 62 26 24 32 41 31 15 41 34 28 21 21 16 20 99 Lines. 22 36 35 30 35 31 28 30 26 40 34 36 30 17 35 41 48 52 58 24 10 14 26 19 24 45 31 22 38 29 26. 22 22 18 24 20 Lines. 35 32 34 32 33 38 30 37 44 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. 37 44 ■ 34 20 Lines. Breadth of plastron at anterior pectoral 44 Breadth of plastron at anterior humeral 20 Breadth of plastron at middle gular groove 13 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 m 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. m 34 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 7 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. G2 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. 11 Lines. 5 G 5 SJ -12" 14 5 0 Gi 7 10 15.^ Transverse. Lines. 4a 4 5 ^ 10-10.} 10^ 23 4i 5 G 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. 50 IG Measurements obtained from lower-jaw fragments detached and not per- taining to tlie preceding : Liues. Lines. Lines. 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 27 41 33 26 24 10 7 114 8.J 19J 9 30J 9 10 ^ 11 64 274 31 31 11 216 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 8 Lines. 16 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. 90 41-45 39 34 Height of fourth inner lobe 30 Height of fourth outer lobe 30 ' 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. 18 13 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 H 7 Lines. S 9 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 7 6 2 53 Bison americanus. Inches. 26 12 11 12 11 10 10 5 2 43 4f 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'iillearauce 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. Lines. Lines. Littcs. Lines. 73 G 54 11 2i 2 ^ 2 Lines. 7 G 1 2i 2 2 1* Lines. Leugtli of series of four teetbj exclud- 15* 12 12 10 8 9 7 5 Length of series of intermediate three teeth 4 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. 4| 3| 5 3J H H 3 3 20* 12.J 2J H 22 4 2i 3 2.r H 2i 3" 0 2i IS li •14 1 Short diameterof crown of fourth tooth. Long diameter of crown of tifth tooth . 1 Short diameter of crown of fifth tooth . a Length of lower branch from back of iiharvniieal. 24* 17* 14 17 lU 10 IG 11 9 14 10 11 8 lOJ Depth of upijer branch to bottom of pliaryngeal Widtli of pharj'ngeal iuferiorly 7 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 ni 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 riosteriorly 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 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 B. 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 D. DeliJbiuidte Dicotyles hesperins liristinns. Dinoceras bxcnstris .. bicaris miraliilis .. Dinosanria 337 216,319 217 216,319 232 95 334 .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 F. Felida; 315 Felis aiigustus 227, 315 imperialis 228,315 Fisbes 184,261,288,346 G. Galeocei'do falcatus 301, 351 Gauoidei 292,348 Glyptosaurus 182, 345 ocellatiis 183 Grapbiodon viucariiis 337 H. 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 I. Icbtbyodorulitcs 353 Icbtbyoruis 266 lusectivora ■ 120 336 L. 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 O. 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 P. 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, S. 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, 328 328 328 221, 328 271 343 344 349 237, 330 109, 335 953,317 Suidse 181, 344 181,344 181, 345 286, 345 113, 335 113 113 335 353 290, 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 U. 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 W. Wasbakius iusignis ._ 123, 336 X. Xiphactiiius audax 290,348 Xystracautbus arcuatns 312, 353 Z. 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 1 *fci»^ "; ,'Sa»= u m \-\ 13 p^# ^*^^^«-4,.^4^ ;^. X /^ 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. CO CO D H o 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. o 03 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. s m o CO Ph < 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," V" -gSsj^feii-j -;..'■ "®^'%^' <,»a5'Sf'^.| i^-*ij «W « jSjisw^-.'^a »- ■^'^Set^i^^JiT^*- ^ji»^7%"* *cV^ *--i^^ T ^ "* •<'~ j( t ^«^^ n"~^-'^. ,-#!*- *..' 3 cr Uc 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,.^ / \\ >^-—'-:~-~ U M ■>>- \ ■ -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^ 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/EOSYy 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 m "3" ^1 * w m .-! ^/, .' n .*- T*>V .J^^' 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;XY. UINTATHERIUM Tho«.Sl,..l.„ri>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^,. ^^;'' V-~i..rr.r-. fW ''■'■<^m m Ai 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'^ ' ^ ^' { V , ^ A .9 \f Til*' SincUir fcSsn.PhTi 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 - <1-hi , «11M;1 ii%Mii mi' '/ 'TF 56 r-'0^ 59 y J> ill'.* jinclsdr ISon. PHl^. 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. I 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 Xi" SincUJr «:Son.Phii.\ *■ '''^^^^^^^^h^^^nf^fif^ mffT^^f^^^^^^^^ ^^^^^^^r\m^N '"1®.t«J?^J*«««,,»Sl, iS^iliiViMiiiii&mk '>'^^,/*>^'<. ^hhmA^f\f\K^2k!^ '^^N^ .^^0,^n/^A^^^O/?. -'^"''';:;:'';?s?^^n^^. 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